Itau Unibanco Holding S.A. (SEC Filing Page | XBRL Cloud Viewer | XBRL Instance)

Line	Label	Object Class	Period Type	Balance	Report ElementName
1	1001 - Document - Document and Entity Information	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DocumentandEntityInformation
2	Implied Table	Table	*	*	implied:Table
3	Document - Document and Entity Information [Abstract]	Abstract			itub:DocumentandEntityInformationAbstract
4	Document Type	Concept (Submission Type)	For Period		dei:DocumentType
5	Amendment Flag	Concept (Yes/No)	For Period		dei:AmendmentFlag
6	Document Period End Date	Concept (Date)	For Period		dei:DocumentPeriodEndDate
7	Document Fiscal Year Focus	Concept (Year)	For Period		dei:DocumentFiscalYearFocus
8	Document Fiscal Period Focus	Concept (Fiscal Period)	For Period		dei:DocumentFiscalPeriodFocus
9	Trading Symbol	Concept (Text/String)	For Period		dei:TradingSymbol
10	Entity Registrant Name	Concept (Text/String)	For Period		dei:EntityRegistrantName
11	Entity Central Index Key	Concept (CIK Number)	For Period		dei:EntityCentralIndexKey
12	Current Fiscal Year End Date	Concept (Month/Day)	For Period		dei:CurrentFiscalYearEndDate
13	Entity Well-known Seasoned Issuer	Concept (Yes/No)	For Period		dei:EntityWellKnownSeasonedIssuer
14	Entity Current Reporting Status	Concept (Yes/No)	For Period		dei:EntityCurrentReportingStatus
15	Entity Filer Category	Concept (Filer Category)	For Period		dei:EntityFilerCategory
16	Entity Common Stock, Shares Outstanding	Concept (Shares)	As Of		dei:EntityCommonStockSharesOutstanding
17	1003 - Statement - Consolidated Balance Sheet	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/StatementOfFinancialPositionCurrentNonCurrent-210000
18	Implied Table	Table	*	*	implied:Table
19	Statement of financial position [abstract]	Abstract			ifrs-full:StatementOfFinancialPositionAbstract
20	Assets	Abstract			ifrs-full:AssetsAbstract
21	Cash and deposits on demand	Concept (Monetary)	As Of	Debit	itub:CashAndDepositsOnDemand
22	Central Bank compulsory deposits	Concept (Monetary)	As Of	Debit	itub:CentralBankCompulsoryDeposits
23	Interbank deposits	Concept (Monetary)	As Of	Debit	ifrs-full:ShorttermDepositsClassifiedAsCashEquivalents
24	Securities purchased under agreements to resell	Concept (Monetary)	As Of	Debit	ifrs-full:ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed
25	Financial assets held for trading	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
26	Pledged as collateral	Concept (Monetary)	As Of	Debit	itub:FinancialAssetsPledgedAsCollateralClassifiedAsHeldForTrading
27	Other	Concept (Monetary)	As Of	Debit	itub:FinancialAssetsOtherClassifiedAsHeldForTrading
28	Financial assets designated at fair value through profit or loss	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLoss
29	Derivatives	Concept (Monetary)	As Of	Debit	ifrs-full:DerivativeFinancialAssets
30	Available-for-sale financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAvailableforsale
31	Pledged as collateral	Concept (Monetary)	As Of	Debit	itub:FinancialAssetsAvailableforsaleFinancialAssetsPledgedAsCollateral
32	Other	Concept (Monetary)	As Of	Debit	itub:FinancialAssetsAvailableforsaleOther
33	Held-to-maturity financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:HeldtomaturityInvestments
34	Pledged as collateral	Concept (Monetary)	As Of	Debit	itub:HeldtomaturityInvestmentsPledgedAsCollateral
35	Other	Concept (Monetary)	As Of	Debit	itub:HeldtomaturityInvestmentsOther
36	Loan operations and lease operations portfolio, net	Concept (Monetary)	As Of	Debit	itub:LoanOperationsAndLeaseOperationsPortfolio
37	Loan operations and lease operations portfolio	Concept (Monetary)	As Of	Debit	itub:LoanOperationsAndLeaseOperationsPortfolioGross
38	Allowance for loan and lease losses	Concept (Monetary)	As Of	Credit	ifrs-full:AllowanceAccountForCreditLossesOfFinancialAssets
39	Other financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:OtherFinancialAssets
40	Investments in associates and joint ventures	Concept (Monetary)	As Of	Debit	itub:InvestmentsInJointVenturesAndAssociates
41	Goodwill	Concept (Monetary)	As Of	Debit	ifrs-full:Goodwill
42	Fixed assets, net	Concept (Monetary)	As Of	Debit	ifrs-full:PropertyPlantAndEquipment
43	Intangible assets, net	Concept (Monetary)	As Of	Debit	ifrs-full:IntangibleAssetsOtherThanGoodwill
44	Tax assets	Concept (Monetary)	As Of	Debit	itub:TaxAssets
45	Income tax and social contribution-current	Concept (Monetary)	As Of	Debit	itub:IncomeTaxAndSocialContributionCurrentAssets
46	Income tax and social contribution-deferred	Concept (Monetary)	As Of	Debit	itub:IncomeTaxAndSocialContributionDeferredAssets
47	Other	Concept (Monetary)	As Of	Debit	itub:IncomeTaxAndSocialContributionOtherAssets
48	Assets held for sale	Concept (Monetary)	As Of	Debit	ifrs-full:NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleOrAsHeldForDistributionToOwners
49	Other assets	Concept (Monetary)	As Of	Debit	ifrs-full:OtherAssets
50	Total assets	Concept (Monetary)	As Of	Debit	ifrs-full:Assets
51	Liabilities and stockholders' equity	Abstract			ifrs-full:EquityAndLiabilitiesAbstract
52	Deposits	Concept (Monetary)	As Of	Credit	ifrs-full:DepositsFromCustomers
53	Securities sold under repurchase agreements	Concept (Monetary)	As Of	Credit	ifrs-full:RepurchaseAgreementsAndCashCollateralOnSecuritiesLent
54	Financial liabilities held for trading	Concept (Monetary)	As Of	Credit	ifrs-full:FinancialLiabilitiesAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
55	Derivatives	Concept (Monetary)	As Of	Credit	ifrs-full:DerivativeFinancialLiabilities
56	Interbank market debt	Concept (Monetary)	As Of	Credit	itub:InterbankMarketDebt
57	Institutional market debt	Concept (Monetary)	As Of	Credit	ifrs-full:DebtSecurities
58	Other financial liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:OtherFinancialLiabilities
59	Reserves for insurance and private pension	Concept (Monetary)	As Of	Credit	ifrs-full:LiabilitiesArisingFromInsuranceContracts
60	Liabilities for capitalization plans	Concept (Monetary)	As Of	Credit	itub:LiabilitiesForCapitalizationPlans
61	Provisions	Concept (Monetary)	As Of	Credit	ifrs-full:Provisions
62	Tax liabilities	Concept (Monetary)	As Of	Credit	itub:TaxLiabilities
63	Income tax and social contribution-current	Concept (Monetary)	As Of	Debit	itub:IncomeTaxAndSocialContributionCurrentLiabilities
64	Income tax and social contribution-deferred	Concept (Monetary)	As Of	Credit	itub:IncomeTaxAndSocialContributionDeferredLiabilities
65	Other	Concept (Monetary)	As Of	Credit	itub:OtherTaxLiabilities
66	Other liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:OtherLiabilities
67	Total liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:Liabilities
68	Capital	Concept (Monetary)	As Of	Credit	ifrs-full:IssuedCapital
69	Treasury shares	Concept (Monetary)	As Of	Debit	ifrs-full:TreasuryShares
70	Additional paid-in capital	Concept (Monetary)	As Of	Credit	ifrs-full:AdditionalPaidinCapital
71	Appropriated reserves	Concept (Monetary)	As Of	Credit	itub:AppropriatedReserves
72	Unappropriated reserves	Concept (Monetary)	As Of	Credit	itub:UnappropriatedReserves
73	Cumulative other comprehensive income	Concept (Monetary)	As Of	Credit	ifrs-full:AccumulatedOtherComprehensiveIncome
74	Total stockholders' equity attributed to the owners of the parent company	Concept (Monetary)	As Of	Credit	ifrs-full:EquityAttributableToOwnersOfParent
75	Non-controlling interests	Concept (Monetary)	As Of	Credit	ifrs-full:NoncontrollingInterests
76	Total stockholders' equity	Concept (Monetary)	As Of	Credit	ifrs-full:Equity
77	Total liabilities and stockholders' equity	Concept (Monetary)	As Of	Credit	ifrs-full:EquityAndLiabilities
78	1004 - Statement - Consolidated Statement of Income	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/StatementOfComprehensiveIncomeProfitOrLossByFunctionOfExpense-310000
79	Statement [Table]	Table	*	*	us-gaap:StatementTable
80	Classes of share capital [axis]	Axis			ifrs-full:ClassesOfShareCapitalAxis
81	Share capital [member]	Member			ifrs-full:ClassesOfShareCapitalMember
82	Ordinary shares [member]	Member			ifrs-full:OrdinarySharesMember
83	Preference shares [member]	Member			ifrs-full:PreferenceSharesMember
84	Statement [Line Items]	LineItems			us-gaap:StatementLineItems
85	Banking product	Concept (Monetary)	For Period	Credit	itub:IncomeFromBankingProduct
86	Interest and similar income	Concept (Monetary)	For Period	Credit	itub:InterestAndSimilarIncome
87	Interest and similar expense	Concept (Monetary)	For Period	Debit	itub:InterestAndSimilarExpense
88	Dividend income	Concept (Monetary)	For Period	Credit	ifrs-full:RevenueFromDividends
89	Net gain (loss) on investment securities and derivatives	Concept (Monetary)	For Period	Credit	itub:GainLossOnInvestmentSecuritiesAndDerivatives
90	Foreign exchange results and exchange variations on transactions	Concept (Monetary)	For Period	Credit	ifrs-full:GainsLossesOnExchangeDifferencesOnTranslationBeforeTax
91	Banking service fees	Concept (Monetary)	For Period	Credit	itub:BankingServiceFees
92	Income related to insurance, private pension and capitalization operations before claim and selling expenses	Concept (Monetary)	For Period	Credit	itub:IncomeRelatedToInsurancePrivatePensionAndCapitalizationOperationsBeforeClaimAndSellingExpenses
93	Income related to insurance and private pension	Concept (Monetary)	For Period	Credit	itub:IncomeRelatedToInsuranceAndPrivatePension
94	Reinsurance Premiums	Concept (Monetary)	For Period	Credit	itub:ReinsurancePremium
95	Change in reserves for insurance and private pension	Concept (Monetary)	For Period	Debit	itub:ChangeInReservesForInsuranceAndPrivatePension
96	Revenue from capitalization plans	Concept (Monetary)	For Period	Credit	itub:RevenueFromCapitalizationPlans
97	Other income	Concept (Monetary)	For Period	Credit	ifrs-full:OtherIncome
98	Losses on loans and claims	Concept (Monetary)	For Period	Debit	ifrs-full:IncreaseDecreaseInInsuranceLiabilitiesNetOfReinsurance
99	Expenses for allowance for loan and lease losses	Concept (Monetary)	For Period	Debit	ifrs-full:ClaimsAndBenefitsPaidNetOfReinsuranceRecoveries
100	Recovery of loans written-off as loss	Concept (Monetary)	For Period	Credit	ifrs-full:PremiumsWrittenNetOfReinsurance
101	Expenses for claims	Concept (Monetary)	For Period	Debit	itub:ExpensesForClaims
102	Recovery of claims under reinsurance	Concept (Monetary)	For Period	Credit	itub:RecoveryOfClaimsUnderReinsurance
103	Banking product net of losses on loans and claims	Concept (Monetary)	For Period	Credit	itub:BankingProductNetOfLossesOnLoansAndClaims
104	Other operating income (expenses)	Concept (Monetary)	For Period	Credit	itub:MiscellaneousOtherOperatingIncomeExpense
105	General and administrative expenses	Concept (Monetary)	For Period	Debit	itub:GeneralAndAdministrativeExpense2
106	Tax expenses	Concept (Monetary)	For Period	Debit	ifrs-full:TaxExpenseOtherThanIncomeTaxExpense
107	Share of profit or (loss) in associates and joint ventures	Concept (Monetary)	For Period	Credit	ifrs-full:ShareOfProfitLossOfAssociatesAndJointVenturesAccountedForUsingEquityMethod
108	Income before income tax and social contribution	Concept (Monetary)	For Period	Credit	itub:ProfitLossBeforeTaxAndSocialContribution
109	Current income tax and social contribution	Concept (Monetary)	For Period	Debit	itub:CurrentIncomeTaxAndSocialContribution
110	Deferred income tax and social contribution	Concept (Monetary)	For Period	Debit	itub:DeferredIncomeTaxAndSocialContribution
111	Net income	Concept (Monetary)	For Period	Credit	ifrs-full:ProfitLoss
112	Net income attributable to owners of the parent company	Concept (Monetary)	For Period	Credit	ifrs-full:ProfitLossAttributableToOwnersOfParent
113	Net income (loss) attributable to non-controlling interests	Concept (Monetary)	For Period	Credit	ifrs-full:ProfitLossAttributableToNoncontrollingInterests
114	Earnings per share - basic	Concept (Share)	For Period		ifrs-full:BasicEarningsLossPerShare
115	Earnings per share - diluted	Concept (Share)	For Period		ifrs-full:DilutedEarningsLossPerShare
116	Weighted average number of shares outstanding - basic	Concept (Shares)	For Period		ifrs-full:WeightedAverageShares
117	Weighted average number of shares outstanding - diluted	Concept (Shares)	For Period		ifrs-full:AdjustedWeightedAverageShares
118	1005 - Statement - Consolidated Statement of Comprehensive Income	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/StatementOfComprehensiveIncomeOCIComponentsPresentedNetOfTax-410000
119	Implied Table	Table	*	*	implied:Table
120	Statement of comprehensive income [abstract]	Abstract			ifrs-full:StatementOfComprehensiveIncomeAbstract
121	Net income	Concept (Monetary)	For Period	Credit	ifrs-full:ProfitLoss
122	Available-for-sale financial assets	Concept (Monetary)	For Period	Credit	ifrs-full:GainsLossesOnRemeasuringAvailableforsaleFinancialAssetsNetOfTax
123	Change in fair value	Concept (Monetary)	For Period	Credit	ifrs-full:OtherComprehensiveIncomeBeforeTaxAvailableforsaleFinancialAssets
124	Income tax effect	Concept (Monetary)	For Period	Debit	ifrs-full:IncomeTaxRelatingToAvailableforsaleFinancialAssetsOfOtherComprehensiveIncome
125	(Gains) / losses transferred to income statement	Concept (Monetary)	For Period	Credit	ifrs-full:GainsLossesOnRemeasuringAvailableforsaleFinancialAssetsBeforeTax
126	Income tax effect	Concept (Monetary)	For Period	Debit	ifrs-full:IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLoss
127	Hedge	Concept (Monetary)	For Period	Credit	ifrs-full:GainLossOnHedgeIneffectivenessRecognisedInOtherComprehensiveIncome
128	Cash flow hedge	Concept (Monetary)	For Period	Credit	ifrs-full:GainsLossesOnCashFlowHedgesNetOfTax
129	Change in fair value	Concept (Monetary)	For Period	Credit	ifrs-full:GainsLossesOnCashFlowHedgesBeforeTax
130	Income tax effect	Concept (Monetary)	For Period	Debit	ifrs-full:IncomeTaxRelatingToCashFlowHedgesOfOtherComprehensiveIncome
131	Hedge of net investment in foreign operation	Concept (Monetary)	For Period	Credit	ifrs-full:GainsLossesOnHedgesOfNetInvestmentsInForeignOperationsNetOfTax
132	Change in fair value	Concept (Monetary)	For Period	Credit	ifrs-full:GainsLossesOnHedgesOfNetInvestmentsInForeignOperationsBeforeTax
133	Income tax effect	Concept (Monetary)	For Period	Debit	ifrs-full:IncomeTaxRelatingToHedgesOfNetInvestmentsInForeignOperationsOfOtherComprehensiveIncome
134	Remeasurements of liabilities for post-employment benefits	Concept (Monetary)	For Period	Credit	ifrs-full:OtherComprehensiveIncomeNetOfTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans
135	Remeasurements	Concept (Monetary)	For Period	Credit	ifrs-full:OtherComprehensiveIncomeBeforeTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans
136	Income tax effect	Concept (Monetary)	For Period	Debit	ifrs-full:IncomeTaxRelatingToRemeasurementsOfDefinedBenefitPlansOfOtherComprehensiveIncome
137	Foreign exchange differences on foreign investments	Concept (Monetary)	For Period	Credit	ifrs-full:GainsLossesOnExchangeDifferencesOnTranslationNetOfTax
138	Total comprehensive income	Concept (Monetary)	For Period	Credit	ifrs-full:ComprehensiveIncome
139	Comprehensive income attributable to non-controlling interests	Concept (Monetary)	For Period	Credit	ifrs-full:ComprehensiveIncomeAttributableToNoncontrollingInterests
140	Comprehensive income attributable to the owners of the parent company	Concept (Monetary)	For Period	Credit	ifrs-full:ComprehensiveIncomeAttributableToOwnersOfParent
141	1006 - Statement - Consolidated Statement of Changes in Stockholders' Equity	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/StatementOfChangesInEquity-610000
142	Statement of changes in equity [table]	Table	*	*	ifrs-full:StatementOfChangesInEquityTable
143	Components of equity [axis]	Axis			ifrs-full:ComponentsOfEquityAxis
144	Equity [member]	Member			ifrs-full:EquityMember
145	Capital [member]	Member			ifrs-full:IssuedCapitalMember
146	Treasury shares [member]	Member			ifrs-full:TreasurySharesMember
147	Additional paid-in capital [member]	Member			ifrs-full:AdditionalPaidinCapitalMember
148	Appropriated reserves [Member]	Member			itub:AppropriatedEarningsMember
149	Unappropriated reserves [member]	Member			itub:UnappropriatedEarningsMember
150	Retained earnings [member]	Member			ifrs-full:RetainedEarningsMember
151	Available-for-sale [member]	Member			ifrs-full:ReserveOfGainsAndLossesOnRemeasuringAvailableforsaleFinancialAssetsMember
152	Remeasurements of liabilities of post-employment benefits [member]	Member			ifrs-full:ReserveOfRemeasurementsOfDefinedBenefitPlansMember
153	Cumulative translation adjustments abroad [member]	Member			ifrs-full:ReserveOfExchangeDifferencesOnTranslationMember
154	Gains and losses - hedge [member]	Member			ifrs-full:ReserveOfCashFlowHedgesMember
155	Equity attributable to owners of parent [member]	Member			ifrs-full:EquityAttributableToOwnersOfParentMember
156	Total stockholders equity non- controlling interests [member]	Member			ifrs-full:NoncontrollingInterestsMember
157	Statement of changes in equity [line items]	LineItems			ifrs-full:StatementOfChangesInEquityLineItems
158	Beginning Balance	Concept (Monetary)	As Of	Credit	ifrs-full:Equity
159	Transactions with owners	Concept (Monetary)	For Period	Credit	ifrs-full:IncreaseDecreaseThroughTransactionsWithOwners
160	Capital increase-Statutory Reserve	Concept (Monetary)	For Period	Credit	ifrs-full:IssueOfEquity
161	Treasury shares-granting of stock options-exercised options	Concept (Monetary)	For Period	Credit	itub:IncreaseDecreaseThroughGrantingOfStockOptionsTreasurySharesEquity
162	Granting of stock options - exercised options	Concept (Monetary)	For Period	Credit	ifrs-full:IncreaseDecreaseThroughExerciseOfOptions
163	Acquisition of treasury shares (Note 21a)	Concept (Monetary)	For Period	Debit	ifrs-full:PurchaseOfTreasuryShares
164	Cancellation of shares	Concept (Monetary)	For Period	Credit	ifrs-full:CancellationOfTreasuryShares
165	Granted options recognized	Concept (Monetary)	For Period	Credit	itub:IncreaseDecreaseThroughGrantedOptionsRecognizedEquity
166	Share-based payment - variable compensation	Concept (Monetary)	For Period	Credit	ifrs-full:IncreaseDecreaseThroughSharebasedPaymentTransactions
167	(Increase) / Reduction of interest of controlling stockholders (Note 2.4a I and 3)	Concept (Monetary)	For Period	Credit	ifrs-full:IncreaseDecreaseThroughChangesInOwnershipInterestsInSubsidiariesThatDoNotResultInLossOfControl
168	Dividends / interest on capital - Special profit reserve (Note 21b)	Concept (Monetary)	For Period	Debit	itub:DividendsOrInterestOnCapitalRecognisedAsDistributionsToOwnersOfParentRelatingToPriorYears
169	Dividends / Interest on capital paid - Special profit reserve	Concept (Monetary)	For Period	Debit	itub:DividendsOrInterestOnCapitalRecognisedAsDistributionsToOwnersOfParentRelatingToCurrentYear
170	Corporate reorganizations (Note 2.4 a III)	Concept (Monetary)	For Period	Credit	itub:IncreaseDecreaseThroughCorporateReorganizationsEquity
171	Other	Concept (Monetary)	For Period	Credit	ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity
172	Total comprehensive income	Concept (Monetary)	For Period	Credit	ifrs-full:ComprehensiveIncome
173	Net income	Concept (Monetary)	For Period	Credit	ifrs-full:ProfitLoss
174	Other comprehensive income for the period	Concept (Monetary)	For Period	Credit	ifrs-full:OtherComprehensiveIncome
175	Appropriations:	Abstract			itub:AppropriationsOfReserveAbstract
176	Legal reserve	Concept (Monetary)	For Period	Credit	itub:IncreaseDecreaseThroughTransferToLegalReserveEquity
177	Statutory reserve	Concept (Monetary)	For Period	Credit	ifrs-full:IncreaseDecreaseThroughTransferToStatutoryReserve
178	Ending Balance	Concept (Monetary)	As Of	Credit	ifrs-full:Equity
179	Change in the period	Concept (Monetary)	For Period	Credit	ifrs-full:ChangesInEquity
180	1007 - Statement - Consolidated Statement of Cash Flows	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/StatementOfCashFlowsIndirectMethod-520000
181	Statement [Table]	Table	*	*	us-gaap:StatementTable
182	Categories of related parties [axis]	Axis			ifrs-full:CategoriesOfRelatedPartiesAxis
183	Entity's total for related parties [member]	Member			ifrs-full:EntitysTotalForRelatedPartiesMember
184	Citibank [Member]	Member			itub:CitibankMember
185	Corp Banca [Member]	Member			itub:CorpBancaMember
186	Recovery acquisition [Member]	Member			itub:RecoveryAcquisitionMember
187	Statement [Line Items]	LineItems			us-gaap:StatementLineItems
188	Adjusted net income	Concept (Monetary)	For Period	Debit	itub:AdjustmentsProfitLoss
189	Net income	Concept (Monetary)	For Period	Credit	ifrs-full:ProfitLoss
190	Adjustments to net income:	Concept (Monetary)	For Period	Debit	ifrs-full:AdjustmentsForReconcileProfitLoss
191	Granted options recognized and share-based payment - variable compensation	Concept (Monetary)	For Period	Debit	ifrs-full:AdjustmentsForSharebasedPayments
192	Effects of changes in exchange rates on cash and cash equivalents	Concept (Monetary)	For Period	Debit	ifrs-full:AdjustmentsForUnrealisedForeignExchangeLossesGains
193	Expenses for allowance for loan and lease losses	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForExpensesForAllowanceForLoanAndLeaseLosses
194	Interest and foreign exchange expense from operations with subordinated debt	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForInterestAndForeignExchangeExpenseFromOperationsWithSubordinatedDebt
195	Change in reserves for insurance and private pension	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForChangeInReservesForInsuranceAndPrivatePension
196	Revenue from capitalization plans	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForRevenueFromCapitalizationPlans
197	Depreciation and amortization	Concept (Monetary)	For Period	Debit	ifrs-full:AdjustmentsForDepreciationAndAmortisationExpense
198	Interest expense from provision for contingent and legal liabilities	Concept (Monetary)	For Period	Debit	ifrs-full:AdjustmentsForFinanceCosts
199	Provision for contingent and legal liabilities	Concept (Monetary)	For Period	Debit	ifrs-full:AdjustmentsForProvisions
200	Interest income related to escrow deposits	Concept (Monetary)	For Period	Credit	ifrs-full:AdjustmentsForInterestIncome
201	Deferred taxes (excluding hedge tax effects)	Concept (Monetary)	For Period	Debit	ifrs-full:AdjustmentsForDeferredTaxExpense
202	Share of profit or (loss) in associates and joint ventures	Concept (Monetary)	For Period	Credit	ifrs-full:AdjustmentsForUndistributedProfitsOfAssociates
203	(Gain) loss on available-for-sale securities	Concept (Monetary)	For Period	Credit	itub:AdjustmentsForGainLossOnAvailableforsaleSecurities
204	Interest and foreign exchange income related to available-for-sale financial assets	Concept (Monetary)	For Period	Credit	itub:AdjustmentsForInterestAndForeignExchangeIncomeRelatedToAvailableforsaleFinancialAssets
205	Interest and foreign exchange income related to held-to-maturity financial assets	Concept (Monetary)	For Period	Credit	itub:AdjustmentsForInterestAndForeignExchangeIncomeRelatedToHeldtomaturityFinancialAssets
206	(Gain) loss on sale of assets held for sale	Concept (Monetary)	For Period	Credit	itub:AdjustmentsForGainLossOnSaleOfAssetsHeldForSale
207	(Gain) loss on sale of investments	Concept (Monetary)	For Period	Credit	itub:AdjustmentsForGainLossOnSaleOfInvestmentSecurities
208	(Gain) loss on sale of fixed assets	Concept (Monetary)	For Period	Credit	ifrs-full:AdjustmentsForGainLossOnDisposalsPropertyPlantAndEquipment
209	Other	Concept (Monetary)	For Period	Debit	ifrs-full:OtherAdjustmentsToReconcileProfitLoss
210	Change in assets and liabilities	Concept (Monetary)	For Period	Credit	ifrs-full:IncreaseDecreaseInWorkingCapital
211	(Increase) decrease in assets	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForDecreaseIncreaseInAssets
212	Interbank deposits	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForIncreaseDecreaseInInterbankDeposits
213	Securities purchased under agreements to resell	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForSecuritiesPurchasedUnderAgreementsToResell
214	Compulsory deposits with the Central Bank of Brazil	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForCompulsoryDepositsWithTheCentralBank
215	Financial assets held for trading	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForFinancialAssetsHeldForTrading
216	Derivatives (assets / liabilities)	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForIncreaseDecreaseInDerivativeAssetsLiabilities
217	Financial assets designated at fair value through profit or loss	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForFinancialAssetsDesignatedAtFairValueThroughProfitOrLoss
218	Loan operations	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForLoanOperations
219	Other financial assets	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForOtherFinancialAssets
220	Other tax assets	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForOtherTaxAssets
221	Other assets	Concept (Monetary)	For Period	Debit	ifrs-full:AdjustmentsForDecreaseIncreaseInOtherAssets
222	(Decrease) increase in liabilities	Concept (Monetary)	For Period	Credit	itub:AdjustmentsForIncreaseDecreaseInLiabilities
223	Deposits	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForIncreaseDecreaseInDeposits
224	Deposits received under securities repurchase agreements	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForIncreaseDecreaseInDepositsReceivedUnderSecuritiesRepurchaseAgreements
225	Financial liabilities held for trading	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForFinancialLiabilitiesHeldForTrading
226	Funds from interbank markets	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForIncreaseDecreaseInFundsFromInterbankMarkets
227	Other financial liabilities	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForIncreaseDecreaseInOtherFinancialLiabilities
228	Technical reserve for insurance and private pension	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForIncreaseDecreaseInTechnicalReserveForInsuranceAndPrivatePension
229	Liabilities for capitalization plans	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForIncreaseDecreaseInLiabilitiesForCapitalizationPlans
230	Provisions	Concept (Monetary)	For Period	Credit	itub:AdjustmentsForIncreaseDecreaseInProvision
231	Tax liabilities	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForIncreaseDecreaseInTaxLiabilities
232	Other liabilities	Concept (Monetary)	For Period	Debit	ifrs-full:AdjustmentsForIncreaseDecreaseInOtherLiabilities
233	Payment of income tax and social contribution	Concept (Monetary)	For Period	Debit	itub:AdjustmentsIncomeTaxAndSocialContributionPaidClassifiedAsOperatingActivities
234	Net cash from (used in) operating activities	Concept (Monetary)	For Period		ifrs-full:CashFlowsFromUsedInOperatingActivities
235	Interest on capital / dividends received from investments in associates and joint ventures	Concept (Monetary)	For Period	Debit	itub:InterestAndDividendsReceivedClassifiedAsInvestingActivities
236	Cash received on sale of available-for-sale financial assets	Concept (Monetary)	For Period	Debit	ifrs-full:ProceedsFromDisposalOrMaturityOfAvailableforsaleFinancialAssets
237	Cash received from redemption of held-to-maturity financial assets	Concept (Monetary)	For Period	Debit	ifrs-full:ProceedsFromSalesOrMaturityOfFinancialInstrumentsClassifiedAsInvestingActivities
238	Cash upon sale of assets held for sale	Concept (Monetary)	For Period	Debit	ifrs-full:ProceedsFromSalesOfInvestmentsOtherThanInvestmentsAccountedForUsingEquityMethod
239	Cash upon sale of investments in associates and joint ventures	Concept (Monetary)	For Period	Debit	ifrs-full:CashFlowsFromLosingControlOfSubsidiariesOrOtherBusinessesClassifiedAsInvestingActivities
240	Cash and cash equivalents, net assets and liabilities from acquisition	Concept (Monetary)	For Period	Credit	ifrs-full:OtherCashPaymentsToAcquireEquityOrDebtInstrumentsOfOtherEntitiesClassifiedAsInvestingActivities
241	Cash upon sale of fixed assets	Concept (Monetary)	For Period	Debit	ifrs-full:ProceedsFromSalesOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities
242	Cash upon sale of intangible assets	Concept (Monetary)	For Period	Debit	ifrs-full:ProceedsFromSalesOfIntangibleAssetsClassifiedAsInvestingActivities
243	Purchase of available-for-sale financial assets	Concept (Monetary)	For Period	Credit	ifrs-full:PurchaseOfAvailableforsaleFinancialAssets
244	Purchase of held-to-maturity financial assets	Concept (Monetary)	For Period	Credit	ifrs-full:PurchaseOfFinancialInstrumentsClassifiedAsInvestingActivities
245	Purchase of investments in associates and joint ventures	Concept (Monetary)	For Period	Credit	ifrs-full:CashFlowsUsedInObtainingControlOfSubsidiariesOrOtherBusinessesClassifiedAsInvestingActivities
246	Purchase of fixed assets	Concept (Monetary)	For Period	Credit	ifrs-full:PurchaseOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities
247	(Cash upon sale) Purchase of intangible assets	Concept (Monetary)	For Period	Credit	ifrs-full:PurchaseOfIntangibleAssetsClassifiedAsInvestingActivities
248	Net cash from (used in) investing activities	Concept (Monetary)	For Period	Debit	ifrs-full:CashFlowsFromUsedInInvestingActivities
249	Funding from institutional markets	Concept (Monetary)	For Period	Debit	ifrs-full:CashFlowsFromUsedInIncreaseDecreaseInCurrentBorrowings
250	Redemptions in institutional markets	Concept (Monetary)	For Period	Credit	ifrs-full:RepaymentsOfNoncurrentBorrowings
251	(Acquisition) / Disposal of interest of non-controlling stockholders	Concept (Monetary)	For Period	Debit	ifrs-full:ProceedsFromContributionsOfNoncontrollingInterests
252	Granting of stock options - exercised options	Concept (Monetary)	For Period	Debit	ifrs-full:ProceedsFromExerciseOfOptions
253	Purchase of treasury shares	Concept (Monetary)	For Period	Debit	ifrs-full:ProceedsFromSaleOrIssueOfTreasuryShares
254	Dividends and interest on capital paid to non-controlling interests	Concept (Monetary)	For Period	Credit	itub:DividendsAndInterestPaidToNoncontrollingInterestsClassifiedAsFinancingActivities
255	Dividends and interest on capital paid	Concept (Monetary)	For Period	Credit	itub:DividendsAndInterestPaidToEquityHoldersOfParentClassifiedAsFinancingActivities
256	Net cash from (used in) financing activities	Concept (Monetary)	For Period	Debit	ifrs-full:CashFlowsFromUsedInFinancingActivities
257	Net increase (decrease) in cash and cash equivalents	Concept (Monetary)	For Period	Debit	ifrs-full:IncreaseDecreaseInCashAndCashEquivalents
258	Cash and cash equivalents at the beginning of the period	Concept (Monetary)	As Of	Debit	ifrs-full:CashAndCashEquivalents
259	Effects of changes in exchange rates on cash and cash equivalents	Concept (Monetary)	For Period	Debit	ifrs-full:EffectOfExchangeRateChangesOnCashAndCashEquivalents
260	Cash and cash equivalents at the end of the period	Concept (Monetary)	As Of	Debit	ifrs-full:CashAndCashEquivalents
261	Additional information on cash flow	Abstract			itub:AdditionalInformationOnCashFlowsAbstract
262	Interest received	Concept (Monetary)	For Period	Debit	ifrs-full:InterestReceivedClassifiedAsOperatingActivities
263	Interest paid	Concept (Monetary)	For Period	Credit	ifrs-full:InterestPaidClassifiedAsOperatingActivities
264	Non-cashtransactions	Abstract			itub:NonCashTransactionsAbstract
265	Loans transferred to assets held for sale	Concept (Monetary)	For Period	Credit	itub:LoansTransferredToAssetsHeldForSale
266	Dividends and interest on capital declared and not yet paid	Concept (Monetary)	For Period	Debit	itub:DividendsAndInterestOnCapitalDeclaredAndNotYetPaid
267	1008 - Disclosure - Overview	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfCompanyOverviewExplanatory
268	Implied Table	Table	*	*	implied:Table
269	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
270	Overview	Concept (Text Block (HTML))	For Period		itub:DisclosureOfCompanyOverviewExplanatory
271	1009 - Disclosure - Significant accounting policies	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfSummaryOfSignificantAccountingPoliciesExplanatory
272	Implied Table	Table	*	*	implied:Table
273	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
274	Significant accounting policies	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfSummaryOfSignificantAccountingPoliciesExplanatory
275	1010 - Disclosure - Business development	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfBusinessCombinationsExplanatory
276	Implied Table	Table	*	*	implied:Table
277	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
278	Business development	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfBusinessCombinationsExplanatory
279	1011 - Disclosure - Cash and cash equivalents	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfCashAndCashEquivalentsExplanatory
280	Implied Table	Table	*	*	implied:Table
281	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
282	Cash and cash equivalents	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfCashAndCashEquivalentsExplanatory
283	1012 - Disclosure - Central Bank compulsory deposits	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfDepositsFromBanksExplanatory
284	Implied Table	Table	*	*	implied:Table
285	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
286	Central Bank compulsory deposits	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfDepositsFromBanksExplanatory
287	1013 - Disclosure - Interbank deposits and securities purchased under agreements to resell	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfInterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResellExplanatory
288	Implied Table	Table	*	*	implied:Table
289	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
290	Interbank deposits and securities purchased under agreements to resell	Concept (Text Block (HTML))	For Period		itub:DisclosureOfInterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResellExplanatory
291	1014 - Disclosure - Financial assets held for trading and designated at fair value through profit or loss	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfFinancialAssetsHeldForTradingAndDesignatedAtFairValueThroughProfitOrLossExplanatory
292	Implied Table	Table	*	*	implied:Table
293	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
294	Financial assets held for trading and designated at fair value through profit or loss	Concept (Text Block (HTML))	For Period		itub:DisclosureOfFinancialAssetsHeldForTradingAndDesignatedAtFairValueThroughProfitOrLossExplanatory
295	1015 - Disclosure - Derivatives	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfDerivativeFinancialInstrumentsExplanatory
296	Implied Table	Table	*	*	implied:Table
297	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
298	Derivatives	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfDerivativeFinancialInstrumentsExplanatory
299	1016 - Disclosure - Hedge accounting	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfGeneralHedgeAccountingExplanatory
300	Implied Table	Table	*	*	implied:Table
301	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
302	Hedge accounting	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfGeneralHedgeAccountingExplanatory
303	1017 - Disclosure - Available-for-sale financial assets	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfAvailableforsaleAssetsExplanatory
304	Implied Table	Table	*	*	implied:Table
305	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
306	Available-for-sale financial assets	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfAvailableforsaleAssetsExplanatory
307	1018 - Disclosure - Held-to-maturity financial assets	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfHeldToMaturityFinancialAssetsExplanatory
308	Implied Table	Table	*	*	implied:Table
309	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
310	Held-to-maturity financial assets	Concept (Text Block (HTML))	For Period		itub:DisclosureOfHeldToMaturityFinancialAssetsExplanatory
311	1019 - Disclosure - Loan operations and lease operations portfolio	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfLoansAndLeaseOperationsPortfolioExplanatory
312	Implied Table	Table	*	*	implied:Table
313	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
314	Loan operations and lease operations portfolio	Concept (Text Block (HTML))	For Period		itub:DisclosureOfLoansAndLeaseOperationsPortfolioExplanatory
315	1020 - Disclosure - Investments in associates and joint ventures	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfInvestmentsAccountedForUsingEquityMethodExplanatory
316	Implied Table	Table	*	*	implied:Table
317	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
318	Investments in associates and joint ventures	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfInvestmentsAccountedForUsingEquityMethodExplanatory
319	1021 - Disclosure - Lease commitments as lessee	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfLeasesExplanatory
320	Implied Table	Table	*	*	implied:Table
321	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
322	Lease commitments as lessee	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfLeasesExplanatory
323	1022 - Disclosure - Fixed assets	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfPropertyPlantAndEquipmentExplanatory
324	Implied Table	Table	*	*	implied:Table
325	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
326	Fixed assets	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfPropertyPlantAndEquipmentExplanatory
327	1023 - Disclosure - Intangible assets	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfIntangibleAssetsExplanatory
328	Implied Table	Table	*	*	implied:Table
329	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
330	Intangible assets	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfIntangibleAssetsExplanatory
331	1024 - Disclosure - Deposits	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfDepositsFromCustomersExplanatory
332	Implied Table	Table	*	*	implied:Table
333	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
334	Deposits	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfDepositsFromCustomersExplanatory
335	1025 - Disclosure - Financial liabilities held for trading	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfFinancialLiabilitiesHeldForTradingExplanatory
336	Implied Table	Table	*	*	implied:Table
337	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
338	Financial liabilities held for trading	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfFinancialLiabilitiesHeldForTradingExplanatory
339	1026 - Disclosure - Securities sold under repurchase agreements and interbank and institutional market debts	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfRepurchaseAndReverseRepurchaseAgreementsExplanatory
340	Implied Table	Table	*	*	implied:Table
341	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
342	Securities sold under repurchase agreements and interbank and institutional market debts	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfRepurchaseAndReverseRepurchaseAgreementsExplanatory
343	1027 - Disclosure - Other assets and liabilities	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfOtherAssetsAndLiabilitiesExplanatory
344	Implied Table	Table	*	*	implied:Table
345	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
346	Other assets and liabilities	Concept (Text Block (HTML))	For Period		itub:DisclosureOfOtherAssetsAndLiabilitiesExplanatory
347	1028 - Disclosure - Stockholders' equity	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfShareCapitalReservesAndOtherEquityInterestExplanatory
348	Implied Table	Table	*	*	implied:Table
349	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
350	Stockholders' equity	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfShareCapitalReservesAndOtherEquityInterestExplanatory
351	1029 - Disclosure - Share-based payment	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfSharebasedPaymentArrangementsExplanatory
352	Implied Table	Table	*	*	implied:Table
353	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
354	Share-based payment	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfSharebasedPaymentArrangementsExplanatory
355	1030 - Disclosure - Interest and similar income and expense and net gain (loss) on investment securities and derivatives	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureInterestAndSimilarIncomeAndExpenseAndNetGainLossOnInvestmentSecuritiesAndDerivativesExplanatory
356	Implied Table	Table	*	*	implied:Table
357	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
358	Interest and similar income and expense and net gain (loss) on investment securities and derivatives	Concept (Text Block (HTML))	For Period		itub:DisclosureInterestAndSimilarIncomeAndExpenseAndNetGainLossOnInvestmentSecuritiesAndDerivativesExplanatory
359	1031 - Disclosure - Banking service fees	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfBankingServiceFeesExplanatory
360	Implied Table	Table	*	*	implied:Table
361	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
362	Banking service fees	Concept (Text Block (HTML))	For Period		itub:DisclosureOfBankingServiceFeesExplanatory
363	1032 - Disclosure - Other income	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfOtherOperatingIncomeExplanatory
364	Implied Table	Table	*	*	implied:Table
365	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
366	Other income	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfOtherOperatingIncomeExplanatory
367	1033 - Disclosure - General and administrative expenses	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfGeneralAndAdministrativeExpenseExplanatory
368	Implied Table	Table	*	*	implied:Table
369	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
370	General and administrative expenses	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfGeneralAndAdministrativeExpenseExplanatory
371	1034 - Disclosure - Income tax and social contribution	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfIncomeTaxExplanatory
372	Implied Table	Table	*	*	implied:Table
373	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
374	Income tax and social contribution	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfIncomeTaxExplanatory
375	1035 - Disclosure - Earnings per share	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfEarningsPerShareExplanatory
376	Implied Table	Table	*	*	implied:Table
377	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
378	Earnings per share	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfEarningsPerShareExplanatory
379	1036 - Disclosure - Post-employment benefits	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfEmployeeBenefitsExplanatory
380	Implied Table	Table	*	*	implied:Table
381	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
382	Post-employment benefits	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfEmployeeBenefitsExplanatory
383	1037 - Disclosure - Insurance contracts	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfInsuranceContractsExplanatory
384	Implied Table	Table	*	*	implied:Table
385	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
386	Insurance contracts	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfInsuranceContractsExplanatory
387	1038 - Disclosure - Fair value of financial instruments	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfFairValueMeasurementExplanatory
388	Implied Table	Table	*	*	implied:Table
389	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
390	Fair value of financial instruments	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfFairValueMeasurementExplanatory
391	1039 - Disclosure - Provisions, contingencies and other commitments	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfOtherProvisionsContingentLiabilitiesAndContingentAssetsExplanatory
392	Implied Table	Table	*	*	implied:Table
393	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
394	Provisions, contingencies and other commitments	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfOtherProvisionsContingentLiabilitiesAndContingentAssetsExplanatory
395	1040 - Disclosure - Regulatory capital	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfRegulatoryCapitalExplanatory
396	Implied Table	Table	*	*	implied:Table
397	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
398	Regulatory capital	Concept (Text Block (HTML))	For Period		itub:DisclosureOfRegulatoryCapitalExplanatory
399	1041 - Disclosure - Segment Information	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfEntitysReportableSegmentsExplanatory
400	Implied Table	Table	*	*	implied:Table
401	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
402	Segment Information	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfEntitysReportableSegmentsExplanatory
403	1042 - Disclosure - Related parties	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfRelatedPartyExplanatory
404	Implied Table	Table	*	*	implied:Table
405	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
406	Related parties	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfRelatedPartyExplanatory
407	1043 - Disclosure - Management risks	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfManagementRiskExplanatory
408	Implied Table	Table	*	*	implied:Table
409	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
410	Management risks	Concept (Text Block (HTML))	For Period		itub:DisclosureOfManagementRiskExplanatory
411	1044 - Disclosure - Supplementary information	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfSupplementaryInformationExplanatory
412	Implied Table	Table	*	*	implied:Table
413	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
414	Supplementary information	Concept (Text Block (HTML))	For Period		itub:DisclosureOfSupplementaryInformationExplanatory
415	1045 - Disclosure - Significant accounting policies (Policies)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfSummaryOfSignificantAccountingPoliciesExplanatoryPolicies
416	Implied Table	Table	*	*	implied:Table
417	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
418	Basis of preparation	Concept (Text Block (HTML))	For Period		itub:DescriptionOfAccountingPolicyForBasisOfPreparationExplanatory
419	New accounting standards and new accounting standards changes and interpretations	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfExpectedImpactOfInitialApplicationOfNewStandardsOrInterpretations
420	Critical accounting estimates and judgments	Concept (Text Block (HTML))	For Period		itub:DescriptionOfAccountingPolicyForCriticalAccountingEstimatesAndJudgmentsExplanatory
421	Consolidation	Concept (Text Block (HTML))	For Period		itub:DescriptionOfAccountingPolicyForConsolidationExplanatory
422	Foreign currency translation	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForForeignCurrencyTranslationExplanatory
423	Cash and cash equivalents	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyToDetermineComponentsOfCashAndCashEquivalents
424	Financial Assets and Liabilities	Concept (Text Block (HTML))	For Period		itub:DescriptionOfAccountingPolicyForFinancialAssetsAndLiabilitiesExplanatory
425	Investments in associates and joint ventures	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForInvestmentInAssociatesAndJointVenturesExplanatory
426	Lease commitments (as lessee)	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForLeasesExplanatory
427	Fixed assets	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForPropertyPlantAndEquipmentExplanatory
428	Goodwill	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForGoodwillExplanatory
429	Intangible assets	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForIntangibleAssetsOtherThanGoodwillExplanatory
430	Assets held for sale	Concept (Text Block (HTML))	For Period		itub:DescriptionOfAccountingPolicyForAssetsHeldForSaleExplanatory
431	Income tax and social contribution	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForIncomeTaxExplanatory
432	Insurance contracts and private pension	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForInsuranceContracts
433	Capitalization plans	Concept (Text Block (HTML))	For Period		itub:DescriptionOfAccountingPolicyForCapitalizationPlansExplanatory
434	Post-employments benefits	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForEmployeeBenefitsExplanatory
435	Share-based payment	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForSharebasedPaymentTransactionsExplanatory
436	Financial guarantees	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForFinancialGuaranteesExplanatory
437	Provisions, contingent assets and contingent liabilities	Concept (Text Block (HTML))	For Period		itub:DescriptionOfAccountingPolicyForProvisionsContingentAssetsAndContingentLiabilitiesExplanatory
438	Capital	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForIssuedCapitalExplanatory
439	Treasury shares	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForTreasurySharesExplanatory
440	Dividends and interest on capital	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForDividendsExplanatory
441	Earnings per share	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForEarningsPerShareExplanatory
442	Revenue from services	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForRecognitionOfRevenue
443	Segment information	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfAccountingPolicyForSegmentReportingExplanatory
444	1046 - Disclosure - Significant accounting policies (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfSummaryOfSignificantAccountingPoliciesExplanatoryTables
445	Implied Table	Table	*	*	implied:Table
446	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
447	Summary of Consolidated Companies	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfSignificantInvestmentsInSubsidiariesExplanatory
448	Summary of Income Tax Rate	Concept (Text Block (HTML))	For Period		itub:DisclosureOfIncomeTaxAndSocialContributionRatesExplanatory
449	1047 - Disclosure - Business development (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfBusinessCombinationsExplanatoryTables
450	Statement [Table]	Table	*	*	us-gaap:StatementTable
451	Business combinations [axis]	Axis			ifrs-full:BusinessCombinationsAxis
452	Entity's total for business combinations [member]	Member			ifrs-full:EntitysTotalForBusinessCombinationsMember
453	Recovery Do Brasil Consultoria [member]	Member			itub:RecoveryDoBrasilConsultoriaMember
454	Maxi Pago Servicos De Internet Sa [Member]	Member			itub:MaxiPagoServicosDeInternetSaMember
455	Statement [Line Items]	LineItems			us-gaap:StatementLineItems
456	Summary of Reconciliation of Changes in Goodwill	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfReconciliationOfChangesInGoodwillExplanatory
457	Summary of Corporate Restructure	Concept (Text Block (HTML))	For Period		itub:DisclosureOfCorporateStructureResultingFromBusinessCombinationsExplanatory
458	Summary of Main Assets Acquired and Liabilities Assumed	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfDetailedInformationAboutBusinessCombinationsExplanatory
459	1048 - Disclosure - Cash and cash equivalents (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfCashAndCashEquivalentsExplanatoryTables
460	Implied Table	Table	*	*	implied:Table
461	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
462	Summary of Cash and Cash Equivalents	Concept (Text Block (HTML))	For Period		itub:DisclosureOfDetailedInformationAboutCashAndCashEquivalentsExplanatory
463	1049 - Disclosure - Central Bank compulsory deposits (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfDepositsFromBanksExplanatoryTables
464	Implied Table	Table	*	*	implied:Table
465	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
466	Summary of Central Bank Compulsory Deposits	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfCashAndBankBalancesAtCentralBanksExplanatory
467	1050 - Disclosure - Interbank deposits and securities purchased under agreements to resell (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfInterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResellExplanatoryTables
468	Implied Table	Table	*	*	implied:Table
469	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
470	Summary of Interbank Deposits and Securities Purchased Under Agreements to Resell	Concept (Text Block (HTML))	For Period		itub:DisclosureOfDetailedInformationAboutInterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResellExplanatory
471	1051 - Disclosure - Financial assets held for trading and designated at fair value through profit or loss (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfFinancialAssetsHeldForTradingAndDesignatedAtFairValueThroughProfitOrLossExplanatoryTables
472	Implied Table	Table	*	*	implied:Table
473	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
474	Summary of Financial Assets Held for Trading Recognized at Fair Value	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfFinancialAssetsHeldForTradingExplanatory
475	Summary of Cost and Fair Value of Financial Assets Held for Trading by Maturity	Concept (Text Block (HTML))	For Period		itub:DisclosureOfMaturityAnalysisForFinancialAssetsHeldForTradingExplanatory
476	Summary of Financial Assets Designated at Fair Value Through Profit or Loss	Concept (Text Block (HTML))	For Period		itub:DisclosureOfFinancialAssetsDesignatedAtFairValueThroughProfitOrLossExplanatory
477	Summary of Cost and Fair Value by Maturity of Financial Assets Designated as Fair Value Through Profit or Loss	Concept (Text Block (HTML))	For Period		itub:DisclosureOfMaturityAnalysisForFinancialAssetsDesignatedAtFairValueThroughProfitOrLossExplanatory
478	1052 - Disclosure - Derivatives (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfDerivativeFinancialInstrumentsExplanatoryTables
479	Implied Table	Table	*	*	implied:Table
480	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
481	Summary of the Composition of Derivatives by Index	Concept (Text Block (HTML))	For Period		itub:DisclosureOfCompositionOfDerivativesByIndexExplanatory
482	Summary of Derivative Contracts Maturity	Concept (Text Block (HTML))	For Period		ifrs-full:MaturityAnalysisForDerivativeFinancialLiabilities
483	Schedule of Composition of Derivative Financial Instruments Portfolio	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfDetailedInformationAboutFinancialInstrumentsExplanatory
484	Disclosure of Portfolio of Credit Derivatives	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfCreditRiskExplanatory
485	Schedule of Notional Amount of Purchased Credit Derivatives	Concept (Text Block (HTML))	For Period		itub:DisclosureOfInformationAboutNotionalAmountsOfCreditDerivativePortfoliosExplanatory
486	Schedule of Financial Assets subject to Offsetting, Enforceable Master Netting Arrangements and Similar Agreements	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfOffsettingOfFinancialAssetsExplanatory
487	Schedule of Financial Liabilities subject to Offsetting, Enforceable Master Netting Arrangements and Similar Agreements	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfOffsettingOfFinancialLiabilitiesExplanatory
488	1053 - Disclosure - Hedge accounting (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfGeneralHedgeAccountingExplanatoryTables
489	Statement [Table]	Table	*	*	us-gaap:StatementTable
490	Types of hedges [axis]	Axis			ifrs-full:TypesOfHedgesAxis
491	Hedges [member]	Member			ifrs-full:TypesOfHedgesMember
492	Cash flow hedges [member]	Member			ifrs-full:CashFlowHedgesMember
493	Hedges of net investment in foreign operations [member]	Member			ifrs-full:HedgesOfNetInvestmentInForeignOperationsMember
494	Fair value hedges [member]	Member			ifrs-full:FairValueHedgesMember
495	Statement [Line Items]	LineItems			us-gaap:StatementLineItems
496	Schedule of Gains (or Losses) of Effective and Ineffective of Strategies of Hedge	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfHedgeAccountingExplanatory
497	Schedule of Each Strategy of Notional Amount and Fair Value Adjustments of Hedge Instruments and Carrying Amount of Hedged Item	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfDetailedInformationAboutHedgedItemsExplanatory
498	Breakdown by Maturity of Hedging Strategies	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfRiskManagementStrategyRelatedToHedgeAccountingExplanatory
499	1054 - Disclosure - Available-for-sale financial assets (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfAvailableforsaleAssetsExplanatoryTables
500	Implied Table	Table	*	*	implied:Table
501	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
502	Summary of Fair Value and Corresponding Cost of Available-for-sale Financial Assets	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfFinancialAssetsExplanatory
503	Summary of Cost and Fair Value of Available-for-sale Financial Assets by Maturity	Concept (Text Block (HTML))	For Period		itub:DisclosureOfMaturityAnalysisOfAvailableforsaleFinancialAssetsExplanatory
504	1055 - Disclosure - Held-to-maturity financial assets (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfHeldToMaturityFinancialAssetsExplanatoryTables
505	Implied Table	Table	*	*	implied:Table
506	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
507	Summary of Amortized Cost of Held-to-maturity Financial Assets	Concept (Text Block (HTML))	For Period		itub:DisclosureOfDetailedInformationAboutHeldtomaturityFinancialAssetsExplanatory
508	Summary of Amortized Cost of Held-to-maturity Financial Assets by Maturity	Concept (Text Block (HTML))	For Period		itub:DisclosureOfMaturityAnalysisOfHeldtomaturityFinancialAssetsExplanatory
509	1056 - Disclosure - Loan operations and lease operations portfolio (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfLoansAndLeaseOperationsPortfolioExplanatoryTables
510	Implied Table	Table	*	*	implied:Table
511	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
512	Summary of Composition of Carrying Amount of Loan Operations and Lease Operations by Type, Sector of Debtor, Maturity and Concentration	Concept (Text Block (HTML))	For Period		itub:DisclosureOfDetailedInformationAboutLoanAndLeaseOperationPortfoliosExplanatory
513	Summary of Changes in the Allowance for Loan and Lease Losses	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfAllowanceForCreditLossesExplanatory
514	Summary of Composition of the Allowance for Loan and Lease Losses by Type of Assessment for Objective Evidence of Impairment	Concept (Text Block (HTML))	For Period		itub:DisclosureOfLoansImpairedLoansAndAllowanceForCreditLossesExplanatory
515	Summary of Analysis of Present Value of Minimum Future Payments Receivable From Finance Leases by Maturity Basically Composed of Individual Operations - Vehicles	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfFinanceLeaseAndOperatingLeaseByLessorExplanatory
516	Summary Sale or Transfer of Financial Assets	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfTransfersOfFinancialAssetsExplanatory
517	1057 - Disclosure - Investments in associates and joint ventures (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfInvestmentsAccountedForUsingEquityMethodExplanatoryTables
518	Implied Table	Table	*	*	implied:Table
519	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
520	Summary of Main Investments	Concept (Text Block (HTML))	For Period		itub:DisclosureOfSignificantInvestmentsInAssociatesAndJointVenturesExplanatory
521	Summary of Aggregate Financial Information of Investees Under Equity Method of Accounting	Concept (Text Block (HTML))	For Period		itub:DisclosureOfFinancialInformationOfEquityMethodInvesteesExplanatory
522	1058 - Disclosure - Lease commitments as lessee (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfLeasesExplanatoryTables
523	Implied Table	Table	*	*	implied:Table
524	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
525	Schedule of Future Minimum Payments	Concept (Text Block (HTML))	For Period		itub:DisclosureOfFinanceLeaseByLesseeExplanatory
526	Schedule of Minimum Payments of Initiated and Remaining Lease Agreements With Non-cancelable Clauses	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfMaturityAnalysisOfOperatingLeasePaymentsExplanatory
527	1059 - Disclosure - Fixed assets (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfPropertyPlantAndEquipmentExplanatoryTables
528	Implied Table	Table	*	*	implied:Table
529	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
530	Summary of Fixed Assets	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfDetailedInformationAboutPropertyPlantAndEquipmentExplanatory
531	1060 - Disclosure - Intangible assets (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfIntangibleAssetsExplanatoryTables
532	Implied Table	Table	*	*	implied:Table
533	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
534	Summary of Intangible Assets	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfDetailedInformationAboutIntangibleAssetsExplanatory
535	1061 - Disclosure - Deposits (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfDepositsFromCustomersExplanatoryTables
536	Implied Table	Table	*	*	implied:Table
537	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
538	Summary of Breakdown of Deposits	Concept (Text Block (HTML))	For Period		itub:DisclosureOfDetailedInformationAboutDepositsFromCustomersExplanatory
539	1062 - Disclosure - Financial liabilities held for trading (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfFinancialLiabilitiesHeldForTradingExplanatoryTables
540	Implied Table	Table	*	*	implied:Table
541	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
542	Summary of Financial Liabilities Held for Trading	Concept (Text Block (HTML))	For Period		itub:DisclosureOfDetailedInformationAboutFinancialLiabilitiesHeldForTradingExplanatory
543	Summary of Fair Value of Financial Liabilities Held for Trading by Maturity	Concept (Text Block (HTML))	For Period		itub:DisclosureOfMaturityAnalysisOfHeldtomaturityFinancialLiabilitiesExplanatory
544	1063 - Disclosure - Securities sold under repurchase agreements and interbank and institutional market debts (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfRepurchaseAndReverseRepurchaseAgreementsExplanatoryTables
545	Implied Table	Table	*	*	implied:Table
546	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
547	Summary of Securities Sold Under Repurchase Agreements and Interbank Market Debt	Concept (Text Block (HTML))	For Period		itub:DisclosureOfDetailedInformationAboutBreakdownOfSecuritiesSoldUnderRepurchaseAgreementAndInterbankMarketDebtExplanatory
548	Summary of Breakdown of Funds Obtained in Institutional Markets	Concept (Text Block (HTML))	For Period		itub:DisclosureOfDetailedInformationAboutBreakdownOfFundsObtainedInInstitutionalMarketsExplanatory
549	Summary of Interest Rate for Each Operations	Concept (Text Block (HTML))	For Period		itub:DisclosureOfDetailedInformationInstitutionalMarketDebtInterestRateExplanatory
550	1064 - Disclosure - Other assets and liabilities (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfOtherAssetsAndLiabilitiesExplanatoryTables
551	Implied Table	Table	*	*	implied:Table
552	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
553	Summary of Other Assets	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfOtherAssetsExplanatory
554	Summary of Other Liabilities	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfOtherLiabilitiesExplanatory
555	1065 - Disclosure - Stockholders' equity (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfShareCapitalReservesAndOtherEquityInterestExplanatoryTables
556	Implied Table	Table	*	*	implied:Table
557	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
558	Summary of Change in Shares of Paid-in Capital and Reconciliation of Balances	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfClassesOfShareCapitalExplanatory
559	Summary of Cost of Shares Purchased and Average Cost of Treasury Shares and Market Price	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfTreasurySharesExplanatory
560	Summary of Calculation of Dividends and Interest on Capital	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfDividendsExplanatory
561	Schedule of Stockholders' Compensation	Concept (Text Block (HTML))	For Period		itub:DisclosureOfShareholdersCompensationExplanatory
562	Summary of Appropriated Reserves	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfReservesAndOtherEquityInterestExplanatory
563	Summary of Non-controlling Interests	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfNoncontrollingInterestsExplanatory
564	1066 - Disclosure - Share-based payment (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfSharebasedPaymentArrangementsExplanatoryTables
565	Statement [Table]	Table	*	*	us-gaap:StatementTable
566	Types of share-based payment arrangements [axis]	Axis			ifrs-full:TypesOfSharebasedPaymentArrangementsAxis
567	Share-based payment arrangements [member]	Member			ifrs-full:SharebasedPaymentArrangementsMember
568	Partner plan [Member]	Member			itub:PartnerPlanMember
569	Variable compensation [Member]	Member			itub:VariableCompensationMember
570	Statement [Line Items]	LineItems			us-gaap:StatementLineItems
571	Summary of Changes in Share-based Compensation Plan	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfNumberAndWeightedAverageExercisePricesOfShareOptionsExplanatory
572	Summary of Changes in Share-based Compensation Plan	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfNumberAndWeightedAverageExercisePricesOfOtherEquityInstrumentsExplanatory
573	1067 - Disclosure - Interest and similar income and expense and net gain (loss) on investment securities and derivatives (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureInterestAndSimilarIncomeAndExpenseAndNetGainLossOnInvestmentSecuritiesAndDerivativesExplanatoryTables
574	Implied Table	Table	*	*	implied:Table
575	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
576	Summary of Interest and Similar Income	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfInterestIncomeExplanatory
577	Summary of Interest and Similar Expense	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfInterestExpenseExplanatory
578	Summary of Net Gain (Loss) on Investment Securities and Derivatives	Concept (Text Block (HTML))	For Period		itub:DisclosureOfGainLossOnInvestmentSecuritiesAndDerivativesExplanatory
579	1068 - Disclosure - Banking service fees (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfBankingServiceFeesExplanatoryTables
580	Implied Table	Table	*	*	implied:Table
581	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
582	Schedule of Banking Service Fees	Concept (Text Block (HTML))	For Period		itub:DisclosureOfDetailedInformationOfBankingServiceFeesExplanatory
583	1069 - Disclosure - Other income (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfOtherOperatingIncomeExplanatoryTables
584	Implied Table	Table	*	*	implied:Table
585	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
586	Summary of Other Income	Concept (Text Block (HTML))	For Period		itub:DisclosureOfDetailedInformationAboutOtherOperatingIncomeExplanatory
587	1070 - Disclosure - General and administrative expenses (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfGeneralAndAdministrativeExpenseExplanatoryTables
588	Implied Table	Table	*	*	implied:Table
589	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
590	Summary of General and Administrative Expenses	Concept (Text Block (HTML))	For Period		itub:DisclosureOfDetailedInformationAboutGeneralAndAdministrativeExpenseExplanatory
591	1071 - Disclosure - Income tax and social contribution (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfIncomeTaxExplanatoryTables
592	Implied Table	Table	*	*	implied:Table
593	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
594	Demonstration of Income Tax and Social Contribution Expense	Concept (Text Block (HTML))	For Period		itub:DisclosureOfDetailedInformationOfIncomeTaxAndSocialContributionExplanatory
595	Summary of Deferred Tax Asset Balance and Respective Changes	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfDeferredTaxesExplanatory
596	Summary of Realization and Present Value of Tax Credits and From Provision for Deferred Income Tax and Social Contribution	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsExplanatory
597	1072 - Disclosure - Earnings per share (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfEarningsPerShareExplanatoryTables
598	Implied Table	Table	*	*	implied:Table
599	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
600	Summary of Earnings Per Share	Concept (Text Block (HTML))	For Period		ifrs-full:EarningsPerShareExplanatory
601	1073 - Disclosure - Post-employment benefits (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfEmployeeBenefitsExplanatoryTables
602	Statement [Table]	Table	*	*	us-gaap:StatementTable
603	Defined benefit plans [axis]	Axis			ifrs-full:DefinedBenefitPlansAxis
604	Defined benefit plans [member]	Member			ifrs-full:DefinedBenefitPlansMember
605	Defined contribution plans [Member]	Member			itub:DefinedContributionPlansMember
606	Other post-employment benefit [Member]	Member			itub:OtherPostEmploymentBenefitMember
607	Defined benefit retirement plans [Member]	Member			itub:DefinedBenefitRetirementPlansMember
608	Statement [Line Items]	LineItems			us-gaap:StatementLineItems
609	Summary of Amounts Recognized in Income for Period	Concept (Text Block (HTML))	For Period		itub:DisclosureOfAmountsRecognizedInIncomeForPeriodExplanatory
610	Summary of Amounts Recognized in Stockholders' Equity - Other Comprehensive Income	Concept (Text Block (HTML))	For Period		itub:DisclosureOfAmountsRecognizedInStockholdersEquityOtherComprehensiveIncomeExplanatory
611	Summary of Main Assumptions Used in Actuarial Valuation of Retirement Plans	Concept (Text Block (HTML))	For Period		itub:DisclosureOfActuarialAssumptionsOnPostEmploymentPlansExplanatory
612	Summary of Allocation of Plan Assets and Allocation Target by Type of Asset	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfDefinedBenefitPlansExplanatory
613	Summary of Calculation of Net Amount Recognized in Balance Sheet, Corresponding to Defined Benefit Plan	Concept (Text Block (HTML))	For Period		itub:DisclosureOfCalculationOfNetAmountRecognizedInBalanceSheetCorrespondingToDefinedBenefitPlanExplanatory
614	Summary of Change in Net Amount Recognized in Balance Sheet	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfNetDefinedBenefitLiabilityAssetExplanatory
615	Summary of Assumptions About Medical Care Cost	Concept (Text Block (HTML))	For Period		itub:DisclosureOfEstimatedPaymentForEmploymentBenefitsExplanatory
616	Summary of Sensitivity of Defined Benefit Obligation	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfSensitivityAnalysisForActuarialAssumptionsExplanatory
617	1074 - Disclosure - Insurance contracts (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfInsuranceContractsExplanatoryTables
618	Implied Table	Table	*	*	implied:Table
619	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
620	Summary of Main Insurance lines	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfTypesOfInsuranceContractsExplanatory
621	Summary of Revenue from Main Insurance and Private Pension	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfAmountsArisingFromInsuranceContractsExplanatory
622	Summary of Changes in Technical Provisions	Concept (Text Block (HTML))	For Period		itub:DisclosureOfChangesInProvisionsExplanatory
623	Summary of Gross Reinsurance Assets	Concept (Text Block (HTML))	For Period		itub:DisclosureOfGrossOfReinsuranceExplanatory
624	Summary of Gross of Reinsurance	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfReinsuranceExplanatory
625	Summary of Sensitivity Analysis Impact in Results and Stockholder's Equity	Concept (Text Block (HTML))	For Period		itub:DisclosureOfReinsuranceContractsExplanatory
626	Summary of Risks of Insurance and Private Pension	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfInsuranceRiskExplanatory
627	Summary of Sensitivity Analysis Presented in Relation to Insurance Operations Demonstrate Impact on Cash Flows Market Value	Concept (Text Block (HTML))	For Period		ifrs-full:SensitivityAnalysisForEachTypeOfMarketRisk
628	Summary of Liquidity Risk	Concept (Text Block (HTML))	For Period		ifrs-full:DisclosureOfLiquidityRiskExplanatory
629	Summary of Risk Level of Financial Assets	Concept (Text Block (HTML))	For Period		itub:DisclosureOfRiskLevelOfFinancialAssetsExplanatory
630	Summary of Changes in Balances of Transactions With Reinsurance Companies	Concept (Text Block (HTML))	For Period		itub:DisclosureOfChangesInBalancesOfTransactionsWithReinsuranceExplanatory
631	Summary of Technical Reserves with Reinsurance Assets	Concept (Text Block (HTML))	For Period		itub:DisclosureOfTechnicalReservesWithReinsuranceAssetsExplanatory
632	Summary of Changes in Balances of Technical Reserves for Reinsurance Claims	Concept (Text Block (HTML))	For Period		itub:DisclosureOfChangesInBalancesOfTechnicalReservesForReinsuranceClaimsExplanatory
633	Summary of Changes in Balances of Technical Reserves for Reinsurance Premiums	Concept (Text Block (HTML))	For Period		itub:DisclosureOfChangesInBalancesOfTechnicalReservesForReinsurancePremiumsExplanatory
634	Summary of Changes in Balances of Technical Reserves for Reinsurance Commission	Concept (Text Block (HTML))	For Period		itub:DisclosureOfChangesInBalancesOfTechnicalReservesForReinsuranceCommissionExplanatory
635	1075 - Disclosure - Fair value of financial instruments (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfFairValueMeasurementExplanatoryTables
636	Implied Table	Table	*	*	implied:Table
637	Text block1 [abstract]	Abstract			itub:TextBlock1Abstract
638	Summary of Carrying and Estimated Fair Values for Financial Instruments	Concept (Text Block (HTML))	For Period		itub:DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesExplanatory
639	Summary of Breakdown of Risk Levels for Financial Assets Held for Trading and Available-For-Sale Financial Assets	Concept (Text Block (HTML))	For Period		itub:FinancialAssetsHeldForTradingAndAvailableforsaleFinancialAssetsExplanatory
640	Summary of Breakdown of Risk Levels for Derivative Assets and Liabilities	Concept (Text Block (HTML))	For Period		itub:DisclosureOfDerivativeFinancialInstrumentExplanatory
641	Summary of Changes in Balance Sheet for Financial Instruments Classified by Level 3 Fair Value Hierarchy	Concept (Text Block (HTML))	For Period		itub:DisclosureOfReconciliationOfChangesInFinancialInstrumentExplanatory
642	Summary of Sensitivity Analyses Operations of Level 3	Concept (Text Block (HTML))	For Period		itub:DisclosureOfFairValueFinancialSensitivityAnalysisExplanatory
643	1076 - Disclosure - Provisions, contingencies and other commitments (Tables)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfOtherProvisionsContingentLiabilitiesAndContingentAssetsExplanatoryTables
644	Statement [Table]	Table	*	*	us-gaap:StatementTable
645	Classes of other provisions [axis]	Axis			ifrs-full:ClassesOfProvisionsAxis
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681	Summary of Breakdown of Indicators of Credit Quality	Concept (Text Block (HTML))	For Period		itub:DisclosureOfCreditQualityPortfolioExplanatory
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692	Summary of Liquidity Indicators	Concept (Text Block (HTML))	For Period		ifrs-full:DescriptionOfManagingLiquidityRisk
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694	Summary of Off Balance Sheet	Concept (Text Block (HTML))	For Period		itub:DisclosureOfContractualMaturitiesOfAssetsAndLiabilitiesAndOffBalanceSheetCommitmentsExplanatory
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730	Hipercard Banco Multiplo S.A. [Member]	Member			itub:HipercardBancoMultiploSAMember
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733	Itau Seguros S.A. [Member]	Member			itub:ItauSegurosSAMember
734	Itau Unibanco SA [Member]	Member			itub:ItauUnibancoSaMember
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737	Redecard S.A. [Member]	Member			itub:RedecardSAMember
738	Itau Corpbanca Colombia S.A. [Member]	Member			itub:ItauCorpbancaColombiaSAMember
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740	Banco Itau Argentina S.A. [Member]	Member			itub:BancoItauArgentinaSAMember
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742	Banco Itau Uruguay S.A. [Member]	Member			itub:BancoItauUruguaySAMember
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746	Itau BBA USA Securities Inc. [Member]	Member			itub:ItauBBAUSASecuritiesIncMember
747	Itau CorpBanca [Member]	Member			itub:ItauCorpbancaMember
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765	Disclosure of business development [Table]	Table	*	*	itub:DisclosureOfBusinessDevelopmentTable
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768	Gestora De Inteligencia De Credito [Member]	Member			itub:GestoraDeInteligenciaDeCreditoMember
769	BancoItau B M G ConsignadoS.A.[Member]	Member			itub:BancoitauBMGConsignadoSAMember
770	Brazil [Member]	Member			country:BR
771	Chile [Member]	Member			country:CL
772	Business combinations [axis]	Axis			ifrs-full:BusinessCombinationsAxis
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775	Conectcar Solucoes de Mobilidade Eletronica S.A. [Member]	Member			itub:ConectCarSolucoesDeMobilidadeEletronicaSAMember
776	Ultrapar Participacoes S. A [Member]	Member			itub:UltraparParticipacoesSAMember
777	Recovery Do Brasil Consultoria [member]	Member			itub:RecoveryDoBrasilConsultoriaMember
778	International Finance Corporation [Member]	Member			itub:InternationalFinanceCorporationMember
779	Itau CorpBanca [Member]	Member			itub:ItauCorpbancaMember
780	Maxi Pago Servicos De Internet Ltda [member]	Member			itub:MaxiPagoServicosDeInternetLtdaMember
781	Categories of related parties [axis]	Axis			ifrs-full:CategoriesOfRelatedPartiesAxis
782	Entity's total for related parties [member]	Member			ifrs-full:EntitysTotalForRelatedPartiesMember
783	Corp Banca [Member]	Member			itub:CorpBancaMember
784	Citibank [Member]	Member			itub:CitibankMember
785	Associates [axis]	Axis			ifrs-full:SignificantInvestmentsInAssociatesAxis
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810	Subscription and payment of shares	Concept (Shares)	For Period		itub:SubscriptionAndPaymentOfShares
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812	Acquisition of shares	Concept (Shares)	For Period		itub:BusinessAcquisitionNumberOfSharesAcquired
813	Percentage of acquired shares	Concept (Percent)	For Period		itub:PercentageOfAcquiredShares
814	Acquisition of common shares	Concept (Shares)	For Period		itub:AcquisitionOfCommonShares
815	Percentage of increased capital	Concept (Percent)	For Period		itub:PercentageOfIncreasedCapital
816	1087 - Disclosure - Business Development - Summary of Reconciliation of Changes in Goodwill (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureBusinessDevelopmentSummaryOfReconciliationOfChangesInGoodwill
817	Disclosure of reconciliation of changes in goodwill [table]	Table	*	*	ifrs-full:DisclosureOfReconciliationOfChangesInGoodwillTable
818	Business combinations [axis]	Axis			ifrs-full:BusinessCombinationsAxis
819	Entity's total for business combinations [member]	Member			ifrs-full:EntitysTotalForBusinessCombinationsMember
820	Banco BTG Pactual SA [Member]	Member			itub:BancoBtgPactualSAMember
821	Maxi Pago Servicos De Internet Ltda [member]	Member			itub:MaxiPagoServicosDeInternetLtdaMember
822	Disclosure of reconciliation of changes in goodwill [line items]	LineItems			ifrs-full:DisclosureOfReconciliationOfChangesInGoodwillLineItems
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824	Fair value of assets and liabilities identified	Concept (Monetary)	As Of	Debit	itub:FairValueOfAssetsAndLiabilities
825	Intangible assets to be amortized	Concept (Monetary)	As Of	Debit	itub:IntangibleAssetAmortization
826	Goodwill	Concept (Monetary)	As Of	Debit	ifrs-full:Goodwill
827	1088 - Disclosure - Business Development - Summary of Corporate Structure (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureBusinessDevelopmentSummaryOfCorporateStructure
828	Disclosure of business development [Table]	Table	*	*	itub:DisclosureOfBusinessDevelopmentTable
829	Categories of related parties [axis]	Axis			ifrs-full:CategoriesOfRelatedPartiesAxis
830	Entity's total for related parties [member]	Member			ifrs-full:EntitysTotalForRelatedPartiesMember
831	Corp Banca [Member]	Member			itub:CorpBancaMember
832	Disclosure of business development [Line Items]	LineItems			itub:DisclosureOfBusinessDevelopmentLineItems
833	Ownership interest	Concept (Percent)	As Of		ifrs-full:PercentageOfVotingEquityInterestsAcquired
834	Other non-controlling stockholders	Concept (Percent)	For Period		ifrs-full:ProportionOfOwnershipInterestsHeldByNoncontrollingInterests
835	1089 - Disclosure - Business Development - Summary of Assets acquired and Liabilities Assumed (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureBusinessDevelopmentSummaryOfAssetsAcquiredAndLiabilitiesAssumed
836	Amounts Recognised As Of Acquisition Date For Each Major Class Of Assets Acquired And Liabilities Assumed [Table]	Table	*	*	itub:AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedTable
837	Business combinations [axis]	Axis			ifrs-full:BusinessCombinationsAxis
838	Entity's total for business combinations [member]	Member			ifrs-full:EntitysTotalForBusinessCombinationsMember
839	Itau CorpBanca [Member]	Member			itub:ItauCorpbancaMember
840	Amounts Recognised As Of Acquisition Date For Each Major Class Of Assets Acquired And Liabilities Assumed [Line Items]	LineItems			itub:AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedLineItems
841	Cash and deposits on demand	Concept (Monetary)	As Of	Debit	itub:CashAndDepositsOnDemand
842	Interbank deposits	Concept (Monetary)	As Of	Debit	itub:InterbankDeposits
843	Securities purchased under agreements to resell	Concept (Monetary)	As Of	Debit	ifrs-full:ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed
844	Financial assets held for trading	Concept (Monetary)	As Of	Debit	itub:FinancialAssetsHeldForTrading
845	Derivatives	Concept (Monetary)	As Of	Debit	ifrs-full:DerivativeFinancialAssets
846	Available-for-sale financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAvailableforsale
847	Held-to-maturity financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:HeldtomaturityInvestments
848	Loan operations and lease operations portfolio, net	Concept (Monetary)	As Of	Debit	itub:LoanOperationsAndLeaseOperationsPortfolio
849	Other financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:OtherFinancialAssets
850	Goodwill	Concept (Monetary)	As Of	Debit	ifrs-full:Goodwill
851	Fixed assets, net	Concept (Monetary)	As Of	Debit	ifrs-full:PropertyPlantAndEquipment
852	Intangible assets, net	Concept (Monetary)	As Of	Debit	ifrs-full:IntangibleAssetsOtherThanGoodwill
853	Tax assets	Concept (Monetary)	As Of	Debit	ifrs-full:DeferredTaxAssets
854	Assets held for sale	Concept (Monetary)	As Of	Debit	ifrs-full:NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSale
855	Other assets	Concept (Monetary)	As Of	Debit	ifrs-full:OtherAssets
856	Total assets	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsRecognisedAsOfAcquisitionDate
857	Deposits	Concept (Monetary)	As Of	Credit	ifrs-full:DepositsFromBanks
858	Securities sold under repurchase agreements	Concept (Monetary)	As Of	Credit	ifrs-full:RepurchaseAgreementsAndCashCollateralOnSecuritiesLent
859	Derivatives	Concept (Monetary)	As Of	Credit	ifrs-full:DerivativeFinancialLiabilities
860	Interbank market debt	Concept (Monetary)	As Of	Credit	itub:InterbankMarketDebt
861	Institucional market debt	Concept (Monetary)	As Of	Credit	itub:InstitutionalMarketDebt
862	Other financial liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:OtherFinancialLiabilities
863	Provisions	Concept (Monetary)	As Of	Credit	ifrs-full:Provisions
864	Tax liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:DeferredTaxLiabilities
865	Other liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:OtherLiabilities
866	Total liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:FinancialLiabilitiesRecognisedAsOfAcquisitionDate
867	Plan net assets	Concept (Monetary)	As Of	Debit	ifrs-full:NetAssetsLiabilities
868	Non-controlling interests	Concept (Monetary)	As Of	Credit	ifrs-full:NoncontrollingInterests
869	Net assets assumed	Concept (Monetary)	As Of	Debit	ifrs-full:IdentifiableAssetsAcquiredLiabilitiesAssumed
870	Adjustment to fair value of net assets assumed	Concept (Monetary)	As Of	Credit	itub:AdjustmentToFairValueOfNetAssetsAssumed
871	Net assets assumed at fair value	Concept (Monetary)	As Of	Debit	itub:FairValueOfIdentifiableAssetsAcquiredAndLiabilitiesAssumed
872	1090 - Disclosure - Cash and Cash Equivalents - Summary of Cash and Cash Equivalents (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureCashAndCashEquivalentsSummaryOfCashAndCashEquivalents
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875	Cash and deposits on demand	Concept (Monetary)	As Of	Debit	itub:CashAndDepositsOnDemand
876	Interbank deposits	Concept (Monetary)	As Of	Debit	itub:InterbankDepositsCurrent
877	Securities purchased under agreements to resell	Concept (Monetary)	As Of	Debit	itub:SecuritiesPurchasedUnderAgreementsToResell2
878	Total	Concept (Monetary)	As Of	Debit	ifrs-full:CashAndCashEquivalents
879	1091 - Disclosure - Cash and Cash Equivalents - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureCashAndCashEquivalentsAdditionalInformation
880	Cash And Cash Equivalents [Table]	Table	*	*	itub:CashAndCashEquivalentsTable
881	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
882	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
883	Interbank deposits [Member]	Member			itub:InterbankDepositsMember
884	Securities purchased under agreements to resell [Member]	Member			itub:SecuritiesPurchasedUnderAgreementsToResellMember
885	Cash and cash equivalents1 [Line Items]	LineItems			itub:CashAndCashEquivalents1LineItems
886	Amounts related to interbank deposits and securities purchased under agreements to resell not included in cash equivalents	Concept (Monetary)	As Of	Debit	itub:InterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResellExcludedFromCashEquivalents
887	1092 - Disclosure - Central Bank Compulsory Deposits - Summary of Central Bank Compulsory Deposits (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureCentralBankCompulsoryDepositsSummaryOfCentralBankCompulsoryDeposits
888	Disclosure Of Deposits From Banks [table]	Table	*	*	itub:DisclosureOfDepositsFromBanksTable
889	Categories of financial liabilities [axis]	Axis			ifrs-full:CategoriesOfFinancialLiabilitiesAxis
890	Financial liabilities, category [member]	Member			ifrs-full:FinancialLiabilitiesCategoryMember
891	Non-interest bearing deposits [Member]	Member			itub:NonInterestBearingDepositsMember
892	Interest-bearing deposits [Member]	Member			itub:InterestBearingDeposits1Member
893	Disclosure of deposits from banks [Line Items]	LineItems			itub:DisclosureOfDepositsFromBanksLineItems
894	Central Bank compulsory deposits	Concept (Monetary)	As Of	Debit	ifrs-full:MandatoryReserveDepositsAtCentralBanks
895	1093 - Disclosure - Interbank Deposits and Securities Purchased Under Agreements to Resell - Summary of Interbank Deposits and Securities Purchased Under Agreements to Resell (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResellSummaryOfInterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResell
896	Disclosure of interbank deposits and securities purchased under agreements to resell [Table]	Table	*	*	itub:DisclosureOfInterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResellTable
897	Past due status [axis]	Axis			ifrs-full:PastDueStatusAxis
898	Past due status [member]	Member			ifrs-full:PastDueStatusMember
899	Current [member]	Member			ifrs-full:CurrentMember
900	Non-current [Member]	Member			itub:NonCurrentMember
901	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
902	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
903	Interbank certificate of deposit [Member]	Member			itub:InterbankCertificateOfDepositMember
904	Disclosure of interbank deposits and securities purchased under agreements to resell [Line Items]	LineItems			itub:DisclosureOfInterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResellLineItems
905	Interbank deposits	Concept (Monetary)	As Of	Debit	itub:InterbankDeposits
906	Securities purchased under agreements to resell	Concept (Monetary)	As Of	Debit	itub:SecuritiesPurchasedUnderAgreementsToResell2
907	Total	Concept (Monetary)	As Of	Debit	itub:InterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResell
908	1094 - Disclosure - Interbank Deposits and Securities Purchased Under Agreements to Resell - Summary of Interbank Deposits and Securities Purchased Under Agreements to Resell (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResellSummaryOfInterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResellParenthetical
909	Disclosure of interbank deposits and securities purchased under agreements to resell [Table]	Table	*	*	itub:DisclosureOfInterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResellTable
910	Borrowings by name [axis]	Axis			ifrs-full:BorrowingsByNameAxis
911	Borrowings by name [member]	Member			ifrs-full:BorrowingsByNameMember
912	B3 S.A. - Brasil, Bolsa, Balco [Member]	Member			itub:BThreeBrasilBolsaBalcoMember
913	Central Bank [Member]	Member			itub:CentralBankMember
914	Geographical areas [axis]	Axis			ifrs-full:GeographicalAreasAxis
915	Geographical areas [member]	Member			ifrs-full:GeographicalAreasMember
916	Other [Member]	Member			itub:OtherCountriesMember
917	Disclosure of interbank deposits and securities purchased under agreements to resell [Line Items]	LineItems			itub:DisclosureOfInterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResellLineItems
918	Amounts pledged in guarantee of operations	Concept (Monetary)	As Of	Debit	itub:PledgedInGuaranteeOfOperations
919	Amounts pledged in guarantee of repurchase agreement transactions	Concept (Monetary)	As Of	Debit	itub:PledgedInGuaranteeOfRepurchaseAgreements
920	Central Bank compulsory deposits	Concept (Monetary)	As Of	Debit	ifrs-full:MandatoryReserveDepositsAtCentralBanks
921	1095 - Disclosure - Financial Assets Held for Trading and Designated at Fair Value Through Profit or Loss - Summary of Financial Assets Held for Trading Recognized at Fair Value (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFinancialAssetsHeldForTradingAndDesignatedAtFairValueThroughProfitOrLossSummaryOfFinancialAssetsHeldForTradingRecognizedAtFairValue
922	Disclosure Of Financial Assets Held For Trading [Table]	Table	*	*	itub:DisclosureOfFinancialAssetsHeldForTradingTable
923	Categories of financial assets [axis]	Axis			ifrs-full:CategoriesOfFinancialAssetsAxis
924	Financial assets, category [member]	Member			ifrs-full:FinancialAssetsCategoryMember
925	Held-for-trading financial assets [Member]	Member			ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTradingCategoryMember
926	Classes of financial instruments [axis]	Axis			ifrs-full:ClassesOfFinancialInstrumentsAxis
927	Financial instruments, class [member]	Member			ifrs-full:ClassesOfFinancialInstrumentsMember
928	Shares [Member]	Member			itub:SharesMember
929	Bank deposit certificates [Member]	Member			itub:BankDepositCertificatesMember
930	Securitized real estate loans [Member]	Member			itub:SecuritizedRealEstateLoansMember
931	Debentures [Member]	Member			itub:DebenturesMember
932	Eurobonds and others [Member]	Member			itub:EurobondsAndOthersMember
933	Financial bills [Member]	Member			itub:FinancialBillsMember
934	Promissory notes [Member]	Member			itub:PromissoryNotesMember
935	Other [Member]	Member			itub:OtherMember
936	Country Name [Axis]	Axis			itub:CountryNameAxis
937	Country Name [Domain]	Member			itub:CountryNameDomain
938	Argentina [Member]	Member			country:AR
939	Chile [Member]	Member			country:CL
940	Colombia [Member]	Member			country:CO
941	United States [Member]	Member			country:US
942	Mexico [Member]	Member			country:MX
943	Paraguay [Member]	Member			country:PY
944	Uruguay [Member]	Member			country:UY
945	Other [Member]	Member			itub:OtherCountriesMember
946	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
947	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
948	Brazilian government securities [Member]	Member			itub:BrazilianGovernmentSecuritiesMember
949	Brazilian external debt bonds [Member]	Member			itub:BrazilianExternalDebtBondsMember
950	Government securities - other countries [Member]	Member			itub:GovernmentSecuritiesMember
951	Corporate securities [Member]	Member			itub:CorporateSecuritiesMember
952	Unconsolidated structured entities [axis]	Axis			ifrs-full:UnconsolidatedStructuredEntitiesAxis
953	Entity's total for unconsolidated structured entities [member]	Member			ifrs-full:EntitysTotalForUnconsolidatedStructuredEntitiesMember
954	Investment funds [member]	Member			ifrs-full:InvestmentFundsMember
955	Disclosure of financial assets held for trading [Line Items]	LineItems			itub:DisclosureOfFinancialAssetsHeldForTradingLineItems
956	Cost	Concept (Monetary)	As Of	Debit	itub:FinancialAssetsAtCostThroughProfitOrLossClassifiedAsHeldForTrading
957	Accumulated gain / (loss) reflected in income	Concept (Monetary)	For Period	Credit	ifrs-full:GainsLossesOnFinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
958	Fair value	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
959	1096 - Disclosure - Financial Assets Held for Trading and Designated at Fair Value Through Profit or Loss - Summary of Financial Assets Held for Trading Recognized at Fair Value (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFinancialAssetsHeldForTradingAndDesignatedAtFairValueThroughProfitOrLossSummaryOfFinancialAssetsHeldForTradingRecognizedAtFairValueParenthetical
960	Disclosure Of Financial Assets Held For Trading [Table]	Table	*	*	itub:DisclosureOfFinancialAssetsHeldForTradingTable
961	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
962	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
963	Brazilian government securities [Member]	Member			itub:BrazilianGovernmentSecuritiesMember
964	Brazilian external debt bonds [Member]	Member			itub:BrazilianExternalDebtBondsMember
965	Government securities - other countries [Member]	Member			itub:GovernmentSecuritiesMember
966	Corporate securities [Member]	Member			itub:CorporateSecuritiesMember
967	Categories of financial assets [axis]	Axis			ifrs-full:CategoriesOfFinancialAssetsAxis
968	Financial assets, category [member]	Member			ifrs-full:FinancialAssetsCategoryMember
969	Held-for-trading financial assets [Member]	Member			ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTradingCategoryMember
970	Disclosure of financial assets held for trading [Line Items]	LineItems			itub:DisclosureOfFinancialAssetsHeldForTradingLineItems
971	Assets held for trading pledged as collateral of funding transactions of financial institutions and clients	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsPledgedAsCollateralForLiabilitiesOrContingentLiabilities
972	Reclassification of held for trading financial assets to other categories of financial assets	Concept (Monetary)	For Period	Debit	ifrs-full:ReclassificationIntoFinancialAssetsAtFairValueThroughProfitOrLoss
973	1097 - Disclosure - Financial Assets Held for Trading and Designated at Fair Value Through Profit or Loss - Summary of Cost and Fair Value of Financial Assets Held for Trading by Maturity (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFinancialAssetsHeldForTradingAndDesignatedAtFairValueThroughProfitOrLossSummaryOfCostAndFairValueOfFinancialAssetsHeldForTradingByMaturity
974	Disclosure of maturity analysis for derivative financial assets [Table]	Table	*	*	itub:DisclosureOfMaturityAnalysisForDerivativeFinancialAssetsTable
975	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
976	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
977	Cost [Member]	Member			itub:FinancialAssetsAtCarryingValueMember
978	Fair value [Member]	Member			ifrs-full:FinancialAssetsAtFairValueMember
979	Maturity [axis]	Axis			ifrs-full:MaturityAxis
980	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
981	Non-stated maturity [Member]	Member			itub:NonstatedMaturityMember
982	Current [Member]	Member			ifrs-full:NotLaterThanOneYearMember
983	1-5 years [Member]	Member			ifrs-full:LaterThanOneYearAndNotLaterThanFiveYearsMember
984	From five to ten years [Member]	Member			ifrs-full:LaterThanFiveYearsAndNotLaterThanTenYearsMember
985	After ten years [Member]	Member			ifrs-full:LaterThanTenYearsMember
986	Disclosure of maturity analysis for derivative financial assets [Line Items]	LineItems			itub:DisclosureOfMaturityAnalysisForDerivativeFinancialAssetsLineItems
987	Cost and fair value of financial assets held for trading by maturity, current	Concept (Monetary)	As Of	Debit	ifrs-full:CurrentFinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
988	Cost and fair value of financial assets held for trading by maturity, non-current	Concept (Monetary)	As Of	Debit	ifrs-full:NoncurrentFinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
989	Total	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
990	1098 - Disclosure - Financial Assets Held for Trading and Designated at Fair Value Through Profit or Loss - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFinancialAssetsHeldForTradingAndDesignatedAtFairValueThroughProfitOrLossAdditionalInformation
991	Disclosure Of Financial Assets Held For Trading [Table]	Table	*	*	itub:DisclosureOfFinancialAssetsHeldForTradingTable
992	Subsidiaries [axis]	Axis			ifrs-full:SignificantInvestmentsInSubsidiariesAxis
993	Entity's total for subsidiaries [member]	Member			ifrs-full:EntitysTotalForSubsidiariesMember
994	Itau Vida e Previdencia S.A. [Member]	Member			itub:ItauVidaePrevidenciaSAMember
995	Disclosure of financial assets held for trading [Line Items]	LineItems			itub:DisclosureOfFinancialAssetsHeldForTradingLineItems
996	Fair value of financial assets held for trading	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLoss
997	1099 - Disclosure - Financial Assets Held for Trading and Designated at Fair Value Through Profit or Loss - Summary of Financial Assets Designated at Fair Value Through Profit or Loss (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFinancialAssetsHeldForTradingAndDesignatedAtFairValueThroughProfitOrLossSummaryOfFinancialAssetsDesignatedAtFairValueThroughProfitOrLoss
998	Disclosure of financial assets designated as measured at fair value through profit or loss [Table]	Table	*	*	itub:DisclosureOfFinancialAssetsDesignatedAsMeasuredAtFairValueThroughProfitOrLossTable
999	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
1000	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
1001	Brazilian external debt bonds [Member]	Member			itub:BrazilianExternalDebtBondsMember
1002	Disclosure of financial assets designated as measured at fair value through profit or loss [Line Items]	LineItems			itub:DisclosureOfFinancialAssetsDesignatedAsMeasuredAtFairValueThroughProfitOrLossLineItems
1003	Cost	Concept (Monetary)	For Period	Debit	itub:FinancialAssetsAtCostThroughProfitOrLoss
1004	Accumulated gain / (loss) reflected in income	Concept (Monetary)	For Period	Credit	ifrs-full:GainsLossesOnFinancialAssetsAtFairValueThroughProfitOrLoss
1005	Fair value	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLoss
1006	1100 - Disclosure - Financial Assets Held for Trading and Designated at Fair Value Through Profit or Loss - Summary of Cost and Fair Value by Maturity of Financial Assets Designated as Fair Value Through Profit or Loss (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFinancialAssetsHeldForTradingAndDesignatedAtFairValueThroughProfitOrLossSummaryOfCostAndFairValueByMaturityOfFinancialAssetsDesignatedAsFairValueThroughProfitOrLoss
1007	Disclosure of maturity analysis for derivative financial assets designated at fair value through profit or loss [Table]	Table	*	*	itub:DisclosureOfMaturityAnalysisForDerivativeFinancialAssetsDesignatedAtFairValueThroughProfitOrLossTable
1008	Maturity [axis]	Axis			ifrs-full:MaturityAxis
1009	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
1010	Current [Member]	Member			ifrs-full:NotLaterThanOneYearMember
1011	1-5 years [Member]	Member			ifrs-full:LaterThanOneYearAndNotLaterThanFiveYearsMember
1012	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
1013	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
1014	Cost [Member]	Member			itub:FinancialAssetsAtCarryingValueMember
1015	Fair value [Member]	Member			ifrs-full:FinancialAssetsAtFairValueMember
1016	Disclosure of maturity analysis for derivative financial assets designated at fair value through profit or loss [Line Items]	LineItems			itub:DisclosureOfMaturityAnalysisForDerivativeFinancialAssetsDesignatedAtFairValueThroughProfitOrLossLineItems
1017	Current	Concept (Monetary)	As Of	Debit	ifrs-full:CurrentFinancialAssetsAtFairValueThroughProfitOrLoss
1018	Non-current	Concept (Monetary)	As Of	Debit	ifrs-full:NoncurrentFinancialAssetsAtFairValueThroughProfitOrLoss
1019	Total	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLoss
1020	1101 - Disclosure - Derivatives - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureDerivativesAdditionalInformation
1021	Disclosure of Financial Assets [Table]	Table	*	*	ifrs-full:DisclosureOfFinancialAssetsTable
1022	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
1023	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
1024	Government securities - other countries [Member]	Member			itub:GovernmentSecuritiesMember
1025	Disclosure of Financial Assets [Line Items]	LineItems			ifrs-full:DisclosureOfFinancialAssetsLineItems
1026	Total value of margins pledged in guarantee	Concept (Monetary)	As Of	Debit	itub:DerivativesPledgesAsCollateral
1027	1102 - Disclosure - Derivatives - Summary of the Composition of Derivatives by Index (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureDerivativesSummaryOfTheCompositionOfDerivativesByIndex
1028	Disclosure of Financial Assets [Table]	Table	*	*	ifrs-full:DisclosureOfFinancialAssetsTable
1029	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
1030	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
1031	Futures [Member]	Member			ifrs-full:FuturesContractMember
1032	Swap [Member]	Member			ifrs-full:SwapContractMember
1033	Option contract [member]	Member			ifrs-full:OptionContractMember
1034	Forward contract [member]	Member			ifrs-full:ForwardContractMember
1035	Credit derivatives [Member]	Member			itub:CreditDerivativesMember
1036	Non Deliverable Forward [Member]	Member			itub:NonDeliverableForwardMember
1037	Check of swap [Member]	Member			itub:CheckOfSwapMember
1038	Other derivative financial instruments [Member]	Member			itub:OtherDerivativeFinancialInstrumentsMember
1039	Maturity [axis]	Axis			ifrs-full:MaturityAxis
1040	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
1041	Non-current [Member]	Member			ifrs-full:LaterThanOneYearMember
1042	Current [Member]	Member			ifrs-full:NotLaterThanOneYearMember
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1045	Purchase commitments [Member]	Member			itub:PurchaseCommitmentsMember
1046	Commodities [Member]	Member			itub:PurchaseCommitmentsCommoditiesMember
1047	Indices [Member]	Member			itub:PurchaseCommitmentsIndicesMember
1048	Interbank market [Member]	Member			itub:PurchaseCommitmentsInterBankMarketMember
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1051	Commitments to sell [Member]	Member			itub:CommitmentsToSellMember
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1057	Securities [Member]	Member			itub:CommitmentsToSellSecuritiesMember
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1132	Classes of liabilities [axis]	Axis			ifrs-full:ClassesOfLiabilitiesAxis
1133	Liabilities [member]	Member			ifrs-full:LiabilitiesMember
1134	Liability position [Member]	Member			itub:CreditDerivativesLiabilityPositionMember
1135	Liability position [Member]	Member			itub:NonDeliverableForwardLiabilityPositionMember
1136	Liability position [Member]	Member			itub:OtherDerivativeFinancialInstrumentsLiabilityPositionMember
1137	Liability position [Member]	Member			itub:LiabilityPositionMember
1138	Disclosure of Financial Assets [Line Items]	LineItems			ifrs-full:DisclosureOfFinancialAssetsLineItems
1139	Off-balance sheet notional amount	Concept (Monetary)	As Of		invest:DerivativeNotionalAmount
1140	Balance sheet account receivable / (received) (payable) paid	Concept (Monetary)	For Period	Debit	itub:BalanceSheetAmountReceivableAndPayable
1141	Adjustment to market value (in results / stockholders' equity)	Concept (Monetary)	For Period	Debit	itub:AdjustmentToMarketValueInResultsStockholdersEquity
1142	Fair value	Concept (Monetary)	As Of	Debit	itub:FairValueOfDerivativeFinancialAssetsLiability
1143	1103 - Disclosure - Derivatives - Summary of Derivative Contracts Maturity (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureDerivativesSummaryOfDerivativeContractsMaturity
1144	Disclosure of maturity analysis for derivative financial liabilities [table]	Table	*	*	ifrs-full:DisclosureOfMaturityAnalysisForDerivativeFinancialLiabilitiesTable
1145	Maturity [axis]	Axis			ifrs-full:MaturityAxis
1146	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
1147	0-30 days [Member]	Member			ifrs-full:NotLaterThanOneMonthMember
1148	31-180 days [Member]	Member			ifrs-full:LaterThanOneMonthAndNotLaterThanSixMonthsMember
1149	181-365 days [Member]	Member			ifrs-full:LaterThanSixMonthsAndNotLaterThanOneYearMember
1150	Non-current [Member]	Member			ifrs-full:LaterThanOneYearMember
1151	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
1152	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
1153	Futures [Member]	Member			ifrs-full:FuturesContractMember
1154	Swap [Member]	Member			ifrs-full:SwapContractMember
1155	Option contract [member]	Member			ifrs-full:OptionContractMember
1156	Forward contract [member]	Member			ifrs-full:ForwardContractMember
1157	Credit derivatives [Member]	Member			itub:CreditDerivativesMember
1158	NDF - Non Deliverable Forward [Member]	Member			itub:NDFNonDeliverableForwardMember
1159	Check of swap [Member]	Member			itub:CheckOfSwapMember
1160	Other derivative financial instruments [Member]	Member			itub:OtherDerivativeFinancialInstrumentsMember
1161	Disclosure of maturity analysis for derivative financial liabilities [line items]	LineItems			ifrs-full:DisclosureOfMaturityAnalysisForDerivativeFinancialLiabilitiesLineItems
1162	Off-balance sheet - notional amount	Concept (Monetary)	As Of		invest:DerivativeNotionalAmount
1163	1104 - Disclosure - Derivatives - Schedule of Composition of Derivative Financial Instruments Portfolio (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureDerivativesScheduleOfCompositionOfDerivativeFinancialInstrumentsPortfolio
1164	Disclosure of detailed information about financial instruments [table]	Table	*	*	ifrs-full:DisclosureOfFinancialInstrumentsTable
1165	Classes of assets [axis]	Axis			ifrs-full:ClassesOfAssetsAxis
1166	Assets [member]	Member			ifrs-full:ClassesOfAssetsMember
1167	Derivative assets [Member]	Member			itub:DerivativeAssetsMember
1168	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
1169	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
1170	Futures [Member]	Member			ifrs-full:FuturesContractMember
1171	Swap [Member]	Member			ifrs-full:SwapContractMember
1172	Optimum Premiums [Member]	Member			itub:OptimumPremiumsMember
1173	Forward contract [member]	Member			ifrs-full:ForwardContractMember
1174	Credit Derivatives Financial Institutions [Member]	Member			itub:CreditDerivativesFinancialInstitutionsMember
1175	Non Deliverable Forward [Member]	Member			itub:NonDeliverableForwardMember
1176	Swaps [Member]	Member			itub:SwapsMember
1177	Classes of financial liabilities [axis]	Axis			ifrs-full:ClassesOfFinancialLiabilitiesAxis
1178	Financial liabilities, class [member]	Member			ifrs-full:FinancialLiabilitiesMember
1179	Swaps [Member]	Member			itub:SwapsMember
1180	Optimum Premiums [Member]	Member			itub:OptimumPremiumsMember
1181	Forwards [member]	Member			itub:ForwardsMember
1182	Non Deliverable Forward [Member]	Member			itub:NonDeliverableForwardMember
1183	Maturity [axis]	Axis			ifrs-full:MaturityAxis
1184	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
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1186	Later than one month and not later than three months [member]	Member			ifrs-full:LaterThanOneMonthAndNotLaterThanThreeMonthsMember
1187	Later than three months and not later than six months [member]	Member			ifrs-full:LaterThanThreeMonthsAndNotLaterThanSixMonthsMember
1188	181-365 days [Member]	Member			ifrs-full:LaterThanSixMonthsAndNotLaterThanOneYearMember
1189	Later than one year and not later than two years [member]	Member			ifrs-full:LaterThanOneYearAndNotLaterThanTwoYearsMember
1190	Later than Two Years [member]	Member			itub:LaterThanTwoYearsMember
1191	Types of financial liabilities [axis]	Axis			ifrs-full:TypesOfFinancialLiabilitiesAxis
1192	Financial liabilities, type [member]	Member			ifrs-full:FinancialLiabilitiesTypeMember
1193	Swaps B3 [Member]	Member			itub:SwapsB3Member
1194	Swaps Companies [Member]	Member			itub:SwapsCompaniesMember
1195	Swaps Financial Institutions [Member]	Member			itub:SwapsFinancialInstitutionsMember
1196	Swaps Individuals [Member]	Member			itub:SwapsIndividualsMember
1197	Credit Derivatives Financial Institutions [Member]	Member			itub:CreditDerivativesFinancialInstitutionsMember
1198	Check Of Swap Companies [Member]	Member			itub:CheckOfSwapCompaniesMember
1199	Swaps Other Companies [Member]	Member			itub:SwapsOtherCompaniesMember
1200	Classes of liabilities [axis]	Axis			ifrs-full:ClassesOfLiabilitiesAxis
1201	Liabilities [member]	Member			ifrs-full:LiabilitiesMember
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1206	Swaps Companies [Member]	Member			itub:SwapsCompaniesMember
1207	Swaps Financial Institutions [Member]	Member			itub:SwapsFinancialInstitutionsMember
1208	Swaps Individuals [Member]	Member			itub:SwapsIndividualsMember
1209	Non Deliverable Forward [Member]	Member			itub:NonDeliverableForwardMember
1210	Check Of Swap Companies [Member]	Member			itub:CheckOfSwapCompaniesMember
1211	Swaps [Member]	Member			itub:SwapsMember
1212	Swap [Member]	Member			ifrs-full:SwapContractMember
1213	Credit Derivatives Financial Institutions [Member]	Member			itub:CreditDerivativesFinancialInstitutionsMember
1214	Disclosure of detailed information about financial instruments [line items]	LineItems			ifrs-full:DisclosureOfFinancialInstrumentsLineItems
1215	Financial assets at fair value	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValue
1216	Financial liabilities at fair value	Concept (Monetary)	As Of	Credit	ifrs-full:FinancialLiabilitiesAtFairValue
1217	% per maturity term	Concept (Percent)	As Of		ifrs-full:AverageRateOfHedgingInstrument
1218	1105 - Disclosure - Derivatives - Schedule of Composition of Derivative Financial Instruments Portfolio (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureDerivativesScheduleOfCompositionOfDerivativeFinancialInstrumentsPortfolioParenthetical
1219	Implied Table	Table	*	*	implied:Table
1220	Disclosure of detailed information about financial instruments [abstract]	Abstract			ifrs-full:DisclosureOfFinancialInstrumentsAbstract
1221	Derivative financial assets, current	Concept (Monetary)	As Of	Debit	ifrs-full:CurrentDerivativeFinancialAssets
1222	Derivative financial assets, non current	Concept (Monetary)	As Of	Debit	ifrs-full:NoncurrentDerivativeFinancialAssets
1223	Derivative financial liabilities, current	Concept (Monetary)	As Of	Credit	ifrs-full:CurrentDerivativeFinancialLiabilities
1224	Derivative financial liabilities, non current	Concept (Monetary)	As Of	Credit	ifrs-full:NoncurrentDerivativeFinancialLiabilities
1225	1106 - Disclosure - Derivatives - Disclosure of Portfolio of Credit Derivatives (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureDerivativesDisclosureOfPortfolioOfCreditDerivatives
1226	Disclosure of credit risk exposure [table]	Table	*	*	ifrs-full:DisclosureOfCreditRiskExposureTable
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1228	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
1229	Current [Member]	Member			ifrs-full:NotLaterThanOneYearMember
1230	Later than one year and not later than three years [member]	Member			ifrs-full:LaterThanOneYearAndNotLaterThanThreeYearsMember
1231	Later than three years and not later than five years [member]	Member			ifrs-full:LaterThanThreeYearsAndNotLaterThanFiveYearsMember
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1233	Classes of financial instruments [axis]	Axis			ifrs-full:ClassesOfFinancialInstrumentsAxis
1234	Financial instruments, class [member]	Member			ifrs-full:ClassesOfFinancialInstrumentsMember
1235	Credit default swaps [member]	Member			itub:CreditDefaultSwapsMember
1236	Types of risks [axis]	Axis			ifrs-full:TypesOfRisksAxis
1237	Risks [member]	Member			ifrs-full:TypesOfRisksMember
1238	Investment grade [Member]	Member			itub:InvestmentGradeMember
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1240	Classes of entity's own equity instruments [axis]	Axis			ifrs-full:ClassesOfEntitysOwnEquityInstrumentsAxis
1241	Entity's own equity instruments [member]	Member			ifrs-full:EntitysOwnEquityInstrumentsMember
1242	Brazilian Government [Member]	Member			itub:BrazilianGovernmentMember
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1244	Private Entities [Member]	Member			itub:PrivateEntitiesMember
1245	Disclosure of credit risk exposure [line items]	LineItems			ifrs-full:DisclosureOfCreditRiskExposureLineItems
1246	Maximum potential amount of future payments	Concept (Monetary)	As Of	Credit	itub:MaximumPotentialAmountOfFuturePayments
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1248	Disclosure Of Information About Notional Amounts Of Credit Derivative Portfolios [Table]	Table	*	*	itub:DisclosureOfInformationAboutNotionalAmountsOfCreditDerivativePortfoliosTable
1249	Classes of financial instruments [axis]	Axis			ifrs-full:ClassesOfFinancialInstrumentsAxis
1250	Financial instruments, class [member]	Member			ifrs-full:ClassesOfFinancialInstrumentsMember
1251	Credit default swaps [member]	Member			itub:CreditDefaultSwapsMember
1252	Disclosure Of Information About Notional Amounts Of Credit Derivative Portfolios [Line Items]	LineItems			itub:DisclosureOfInformationAboutNotionalAmountsOfCreditDerivativePortfoliosLineItems
1253	Notional amount of credit protection sold	Concept (Monetary)	For Period	Credit	itub:NotionalAmountofCreditProtectionSold
1254	Notional amount of credit protection purchased with identical underlying amount	Concept (Monetary)	For Period	Debit	itub:NotionalAmountofCreditProtectionPurchasedwithIdenticalUnderlyingAmount
1255	Net position	Concept (Monetary)	For Period	Credit	itub:NetPosition
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1257	Disclosure of offsetting of financial assets [table]	Table	*	*	ifrs-full:DisclosureOfOffsettingOfFinancialAssetsTable
1258	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
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1260	Securities purchased under agreements to resell [Member]	Member			itub:SecuritiesPurchasedUnderAgreementsToResellMember
1261	Derivatives [member]	Member			ifrs-full:DerivativesMember
1262	Disclosure of offsetting of financial assets [line items]	LineItems			ifrs-full:DisclosureOfOffsettingOfFinancialAssetsLineItems
1263	Gross amount of recognized financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:GrossFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements
1264	Gross amount offset in the statement of financial position	Concept (Monetary)	As Of	Credit	ifrs-full:GrossFinancialLiabilitiesSetOffAgainstFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements
1265	Net amount of financial assets presented in the statement of financial position	Concept (Monetary)	As Of	Debit	ifrs-full:NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition
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1268	Net amount	Concept (Monetary)	As Of	Debit	ifrs-full:NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements
1269	Gross amount of recognized financial liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:GrossFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements
1270	Gross amount offset in the statement of financial position	Concept (Monetary)	As Of	Debit	ifrs-full:GrossFinancialAssetsSetOffAgainstFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements
1271	Net amount of financial assets presented in the statement of financial position	Concept (Monetary)	As Of	Credit	ifrs-full:NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition
1272	Related amounts not offset in the statement of Financial position, financial instruments	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialInstrumentsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilities
1273	Related amounts not offset in the statement of Financial position, cash collateral received	Concept (Monetary)	As Of	Debit	ifrs-full:CashCollateralPledgedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilities
1274	Net amount	Concept (Monetary)	As Of	Credit	ifrs-full:NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements
1275	1109 - Disclosure - Hedge Accounting - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureHedgeAccountingAdditionalInformation
1276	Implied Table	Table	*	*	implied:Table
1277	Disclosure of detailed information about hedges [abstract]	Abstract			ifrs-full:DisclosureOfHedgeAccountingAbstract
1278	Description of type of hedge	Concept (Text/String)	For Period		ifrs-full:DescriptionOfTypeOfHedge
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1280	Disclosure of Detailed Information about Hedges [Table]	Table	*	*	ifrs-full:DisclosureOfHedgeAccountingTable
1281	Types of hedges [axis]	Axis			ifrs-full:TypesOfHedgesAxis
1282	Hedges [member]	Member			ifrs-full:TypesOfHedgesMember
1283	Cash flow hedges [member]	Member			ifrs-full:CashFlowHedgesMember
1284	Hedges of net investment in foreign operations [member]	Member			ifrs-full:HedgesOfNetInvestmentInForeignOperationsMember
1285	Fair value hedges [member]	Member			ifrs-full:FairValueHedgesMember
1286	Hedging instruments [axis]	Axis			ifrs-full:HedgingInstrumentsAxis
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1288	Interest rate futures [member]	Member			itub:InterestRateFuturesMember
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1292	Non deliverable forward contract [Member]	Member			itub:NonDeliverableForwardContractMember
1293	Financial assets held for hedging[Member]	Member			itub:FinancialAssetsHeldForHedgingMember
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1296	Forward contract [member]	Member			ifrs-full:ForwardContractMember
1297	Disclosure of Detailed Information about Hedges [Line Items]	LineItems			ifrs-full:DisclosureOfHedgeAccountingLineItems
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1300	Accumulated effective portion	Concept (Monetary)	As Of	Credit	itub:AccumulatedEffectivePortionGainsLossesOfHedgesOfNetInvestmentsInForeignOperationsRecognisedInProfitOrLoss
1301	Ineffective portion	Concept (Monetary)	For Period	Credit	ifrs-full:GainsLossesOnIneffectivenessOfHedgesOfNetInvestmentsInForeignOperations
1302	Accumulated effective portion	Concept (Monetary)	As Of	Credit	itub:AccumulatedEffectivePortionGainLossOnChangeInFairValueOfHedgingInstrumentUsedAsBasisForRecognisedInProfitOrLoss
1303	Ineffective portion	Concept (Monetary)	For Period	Credit	ifrs-full:GainLossOnChangeInFairValueOfHedgingInstrumentUsedAsBasisForRecognisingHedgeIneffectiveness
1304	1111 - Disclosure - Hedge Accounting - Schedule of Each Strategy of Notional Amount and Fair Value Adjustments of Hedge Instruments and Carrying Amount of Hedged Item (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureHedgeAccountingScheduleOfEachStrategyOfNotionalAmountAndFairValueAdjustmentsOfHedgeInstrumentsAndCarryingAmountOfHedgedItem
1305	Disclosure of detailed information about hedged items [table]	Table	*	*	ifrs-full:DisclosureOfDetailedInformationAboutHedgedItemsTable
1306	Types of hedges [axis]	Axis			ifrs-full:TypesOfHedgesAxis
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1308	Hedges of net investment in foreign operations [member]	Member			ifrs-full:HedgesOfNetInvestmentInForeignOperationsMember
1309	Cash flow hedges [member]	Member			ifrs-full:CashFlowHedgesMember
1310	Types of risks [axis]	Axis			ifrs-full:TypesOfRisksAxis
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1316	Hedge Of Syndicated Loan [Member]	Member			itub:HedgeOfSyndicatedLoanMember
1317	Hedge Of Highly Probable Forecast Transactions [Member]	Member			itub:HedgeOfHighlyProbableForecastTransactionsMember
1318	Hedge Of Loan Operations [Member]	Member			itub:HedgeOfLoanOperationsMember
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1320	Hedge Of Asset Backed Securities Under Repurchase Agreements [Member]	Member			itub:HedgeOfAssetBackedSecuritiesUnderRepurchaseAgreementsMember
1321	Hedge Of Assets Denominated In U F [Member]	Member			itub:HedgeOfAssetsDenominatedInUFMember
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1326	Disclosure of detailed information about hedged items [line items]	LineItems			ifrs-full:DisclosureOfDetailedInformationAboutHedgedItemsLineItems
1327	Hedge instruments, notional amount	Concept (Monetary)	As Of		ifrs-full:NotionalAmount
1328	Hedge instruments, fair value adjustments	Concept (Monetary)	As Of		ifrs-full:FinancialInstrumentsDesignatedAsHedgingInstrumentsAtFairValue
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1330	1112 - Disclosure - Hedge Accounting - Schedule of Each Strategy of Notional Amount and Fair Value Adjustments of Hedge Instruments and Carrying Amount of Hedged Item (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureHedgeAccountingScheduleOfEachStrategyOfNotionalAmountAndFairValueAdjustmentsOfHedgeInstrumentsAndCarryingAmountOfHedgedItemParenthetical
1331	Disclosure of detailed information about hedged items [table]	Table	*	*	ifrs-full:DisclosureOfDetailedInformationAboutHedgedItemsTable
1332	Types of hedges [axis]	Axis			ifrs-full:TypesOfHedgesAxis
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1334	Hedges of net investment in foreign operations [member]	Member			ifrs-full:HedgesOfNetInvestmentInForeignOperationsMember
1335	Disclosure of detailed information about hedged items [line items]	LineItems			ifrs-full:DisclosureOfDetailedInformationAboutHedgedItemsLineItems
1336	Hedge instruments over hedge rate related to taxes	Concept (Percent)	For Period		itub:HedgeInstrumentsOverhedgeRateRelatedToTaxes
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1338	Disclosure of risk management strategy related to hedge accounting [table]	Table	*	*	ifrs-full:DisclosureOfRiskManagementStrategyRelatedToHedgeAccountingTable
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1359	Hedge Of Loan Operations [Member]	Member			itub:HedgeOfLoanOperationsMember
1360	Hedge Of Syndicated Loan [Member]	Member			itub:HedgeOfSyndicatedLoanMember
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1362	Hedge Of Asset Backed Securities Under Repurchase Agreements [Member]	Member			itub:HedgeOfAssetBackedSecuritiesUnderRepurchaseAgreementsMember
1363	Hedge Of Assets Denominated In U F [Member]	Member			itub:HedgeOfAssetsDenominatedInUFMember
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1371	Disclosure of Financial Assets [Table]	Table	*	*	ifrs-full:DisclosureOfFinancialAssetsTable
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1465	Disclosure of held to maturity financial assets [Line Items]	LineItems			itub:DisclosureOfHeldToMaturityFinancialAssetsLineItems
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1618	Classes of assets [axis]	Axis			ifrs-full:ClassesOfAssetsAxis
1619	Assets [member]	Member			ifrs-full:ClassesOfAssetsMember
1620	Vehicles [member]	Member			ifrs-full:VehiclesMember
1621	Disclosure of loans and lease operations [Line Items]	LineItems			itub:DisclosureOfLoansAndLeaseOperationsLineItems
1622	Assets	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssets
1623	Liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:FinancialLiabilities
1624	1130 - Disclosure - Investments in Associates and Joint Ventures - Summary of Main Investments (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInvestmentsInAssociatesAndJointVenturesSummaryOfMainInvestments
1625	Disclosure of investments in associates and joint ventures [Table]	Table	*	*	itub:DisclosureOfInvestmentsInAssociatesAndJointVenturesTable
1626	Investment Holding [Axis]	Axis			invest:InvestmentHoldingAxis
1627	Investment Holding [Domain]	Member			invest:InvestmentHoldingDomain
1628	Porto Seguro Itau Unibanco Participacoes S.A. [Member]	Member			itub:PortoSeguroItauUnibancoParticipacoesSAMember
1629	BSF Holding S.A. [Member]	Member			itub:BSFHoldingSAMember
1630	IRB-Brasil Resseguros S.A. [Member]	Member			itub:IRBBrasilRessegurosSAMember
1631	Other [Member]	Member			itub:OtherAssociatesMember
1632	Joint Ventures - Other [Member]	Member			itub:OtherJointVenturesMember
1633	Disclosure of investments in associates and joint ventures [Line Items]	LineItems			itub:DisclosureOfInvestmentsInAssociatesAndJointVenturesLineItems
1634	Total interest	Concept (Percent)	For Period		itub:InvestmentOwnershipPercentageInAssociatesAndJointVentures
1635	Voting interest	Concept (Percent)	For Period		itub:InvestmentVotingPercentageInAssociatesAndJointVentures
1636	Stockholders' equity	Concept (Monetary)	As Of	Credit	ifrs-full:Equity
1637	Other Comprehensive Income	Concept (Monetary)	For Period	Credit	ifrs-full:OtherComprehensiveIncome
1638	Net income	Concept (Monetary)	For Period	Credit	itub:NetInvestmentIncomeLoss
1639	Investment	Concept (Monetary)	As Of	Debit	itub:InvestmentCarryingValue
1640	Equity in earnings	Concept (Monetary)	For Period	Credit	itub:EquityInEarningsOfAssociatesAndJointVentures
1641	Market value	Concept (Monetary)	As Of	Debit	itub:InvestmentMarketValue
1642	Equity in earnings	Concept (Monetary)	For Period	Credit	itub:EquityInEarningsOfUnconsolidatedInvesteesNet
1643	1131 - Disclosure - Investments in Associates and Joint Ventures - Summary of Main Investments (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInvestmentsInAssociatesAndJointVenturesSummaryOfMainInvestmentsParenthetical
1644	Disclosure of investments in associates and joint ventures [Table]	Table	*	*	itub:DisclosureOfInvestmentsInAssociatesAndJointVenturesTable
1645	Investment Holding [Axis]	Axis			invest:InvestmentHoldingAxis
1646	Investment Holding [Domain]	Member			invest:InvestmentHoldingDomain
1647	Porto Seguro Itau Unibanco Participacoes S.A. [Member]	Member			itub:PortoSeguroItauUnibancoParticipacoesSAMember
1648	Business combinations [axis]	Axis			ifrs-full:BusinessCombinationsAxis
1649	Entity's total for business combinations [member]	Member			ifrs-full:EntitysTotalForBusinessCombinationsMember
1650	BSF Holding S.A. [Member]	Member			itub:BSFHoldingSAMember
1651	Joint ventures [axis]	Axis			ifrs-full:JointVenturesAxis
1652	Entity's total for joint ventures [member]	Member			ifrs-full:EntitysTotalForJointVenturesMember
1653	Gestora De Inteligencia De Credito S A [Member]	Member			itub:GestoraDeInteligenciaDeCreditoSAMember
1654	Compania Uruguaya De Medios De Procesamiento S A [Member]	Member			itub:CompaniaUruguayaDeMediosDeProcesamientoSAMember
1655	Rias Redbanc S A [Member]	Member			itub:RiasRedbancSAMember
1656	Kinea Private Equity Investimentos S A [Member]	Member			itub:KineaPrivateEquityInvestimentosSAMember
1657	Tecnologia Bancaria S A [Member]	Member			itub:TecnologiaBancariaSAMember
1658	Olimpia Promocao e Servicos S.A. [Member]	Member			itub:OlimpiaPromocaoEServicosSAMember
1659	Conectcar Solucoes de Mobilidade Eletronica S.A. [Member]	Member			itub:ConectCarSolucoesDeMobilidadeEletronicaSAMember
1660	IRB-Brasil Resseguros S.A. [Member]	Member			itub:IRBBrasilRessegurosSAMember
1661	BSF Holding S.A. [Member]	Member			itub:BSFHoldingSAMember
1662	Porto Seguro Itau Unibanco Participacoes S.A. [Member]	Member			itub:PortoSeguroItauUnibancoParticipacoesSAMember
1663	Disclosure of investments in associates and joint ventures [Line Items]	LineItems			itub:DisclosureOfInvestmentsInAssociatesAndJointVenturesLineItems
1664	Amount of difference between interest in net asset at fair value and book value	Concept (Monetary)	As Of	Debit	itub:AmountOfDifferenceBetweenInterestInNetAssetAtFairValueAndBookValue
1665	Business combination, Number of shares acquired	Concept (Shares)	For Period		itub:BusinessAcquisitionNumberOfSharesAcquired
1666	Total consideration acquired	Concept (Monetary)	As Of	Credit	ifrs-full:AcquisitiondateFairValueOfTotalConsiderationTransferred
1667	Percentage of voting interest acquired	Concept (Percent)	As Of		ifrs-full:PercentageOfVotingEquityInterestsAcquired
1668	Amount of goodwill acquired	Concept (Monetary)	For Period	Debit	itub:GoodwillAcquiredThroughBusinessCombination
1669	Percentage interest in total capital	Concept (Percent)	For Period		itub:InvestmentOwnershipPercentageInAssociates
1670	Percentage interest in voting capital	Concept (Percent)	For Period		itub:InvestmentVotingPercentageInAssociates
1671	Percentage interest in total capital	Concept (Percent)	For Period		itub:InvestmentOwnershipPercentageJointVentures
1672	Percentage interest in voting capital	Concept (Percent)	For Period		itub:InvestmentVotingPercentageInJointVentures
1673	Recognizes dividends and interest on capital	Concept (Monetary)	For Period	Debit	itub:DividendAndInterestOnCapital
1674	1132 - Disclosure - Investments in Associates and Joint Ventures - Summary of Aggregate Financial Information of Investees Under Equity Method of Accounting (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInvestmentsInAssociatesAndJointVenturesSummaryOfAggregateFinancialInformationOfInvesteesUnderEquityMethodOfAccounting
1675	Disclosure of investments in associates and joint ventures [Table]	Table	*	*	itub:DisclosureOfInvestmentsInAssociatesAndJointVenturesTable
1676	Classes of assets [axis]	Axis			ifrs-full:ClassesOfAssetsAxis
1677	Assets [member]	Member			ifrs-full:ClassesOfAssetsMember
1678	Investments accounted for using equity method [member]	Member			ifrs-full:InvestmentsAccountedForUsingEquityMethodMember
1679	Disclosure of investments in associates and joint ventures [Line Items]	LineItems			itub:DisclosureOfInvestmentsInAssociatesAndJointVenturesLineItems
1680	Total assets	Concept (Monetary)	As Of	Debit	ifrs-full:Assets
1681	Total liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:Liabilities
1682	Total Income	Concept (Monetary)	For Period	Credit	ifrs-full:Revenue
1683	Total Expenses	Concept (Monetary)	For Period	Debit	ifrs-full:ExpenseByNature
1684	1133 - Disclosure - Investments in Associates and Joint Ventures - Summary of Aggregate Financial Information of Investees Under Equity Method of Accounting (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInvestmentsInAssociatesAndJointVenturesSummaryOfAggregateFinancialInformationOfInvesteesUnderEquityMethodOfAccountingParenthetical
1685	Disclosure of investments in associates and joint ventures [Table]	Table	*	*	itub:DisclosureOfInvestmentsInAssociatesAndJointVenturesTable
1686	Investment Holding [Axis]	Axis			invest:InvestmentHoldingAxis
1687	Investment Holding [Domain]	Member			invest:InvestmentHoldingDomain
1688	IRB-Brasil Resseguros S.A. [Member]	Member			itub:IRBBrasilRessegurosSAMember
1689	Classes of assets [axis]	Axis			ifrs-full:ClassesOfAssetsAxis
1690	Assets [member]	Member			ifrs-full:ClassesOfAssetsMember
1691	Investments accounted for using equity method [member]	Member			ifrs-full:InvestmentsAccountedForUsingEquityMethodMember
1692	Disclosure of investments in associates and joint ventures [Line Items]	LineItems			itub:DisclosureOfInvestmentsInAssociatesAndJointVenturesLineItems
1693	Assets	Concept (Monetary)	As Of	Debit	ifrs-full:Assets
1694	Liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:Liabilities
1695	Income	Concept (Monetary)	For Period	Credit	ifrs-full:Revenue
1696	Expense	Concept (Monetary)	For Period	Debit	ifrs-full:ExpenseByNature
1697	1134 - Disclosure - Lease Commitments as Lessee - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureLeaseCommitmentsAsLesseeAdditionalInformation
1698	Disclosure of finance lease and operating lease by lessee [table]	Table	*	*	ifrs-full:DisclosureOfFinanceLeaseAndOperatingLeaseByLesseeTable
1699	Statement of comprehensive income, profit or loss location [axis]	Axis			itub:StatementOfComprehensiveIncomeProfitOrLossLocationAxis
1700	Income Statement Location [Domain]	Member			us-gaap:IncomeStatementLocationDomain
1701	General and Administrative Expense [Member]	Member			us-gaap:GeneralAndAdministrativeExpenseMember
1702	Disclosure of finance lease and operating lease by lessee [line items]	LineItems			ifrs-full:DisclosureOfFinanceLeaseAndOperatingLeaseByLesseeLineItems
1703	Net carrying amount of finance lease assets	Concept (Monetary)	As Of	Debit	ifrs-full:RecognisedFinanceLeaseAsAssets
1704	Operating lease expenses	Concept (Monetary)	For Period	Debit	ifrs-full:MinimumOperatingLeasePayments
1705	1135 - Disclosure - Lease Commitments as Lessee - Schedule of Future Minimum Payments (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureLeaseCommitmentsAsLesseeScheduleOfFutureMinimumPayments
1706	Disclosure of finance lease and operating lease by lessee [table]	Table	*	*	ifrs-full:DisclosureOfFinanceLeaseAndOperatingLeaseByLesseeTable
1707	Past due status [axis]	Axis			ifrs-full:PastDueStatusAxis
1708	Past due status [member]	Member			ifrs-full:PastDueStatusMember
1709	Current [member]	Member			ifrs-full:CurrentMember
1710	Maturity [axis]	Axis			ifrs-full:MaturityAxis
1711	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
1712	Current [Member]	Member			ifrs-full:NotLaterThanOneYearMember
1713	Disclosure of finance lease and operating lease by lessee [line items]	LineItems			ifrs-full:DisclosureOfFinanceLeaseAndOperatingLeaseByLesseeLineItems
1714	Future minimum payments, finance lease	Concept (Monetary)	As Of	Credit	ifrs-full:MinimumFinanceLeasePaymentsPayable
1715	(-) Future interest	Concept (Monetary)	As Of	Credit	ifrs-full:FutureFinanceChargeOnFinanceLease
1716	Future minimum payments, finance lease	Concept (Monetary)	As Of	Credit	ifrs-full:MinimumFinanceLeasePaymentsPayableAtPresentValue
1717	1136 - Disclosure - Lease Commitments as Lessee - Schedule of Minimum Payments of Initiated and Remaining Lease Agreements With Non-cancelable Clauses (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureLeaseCommitmentsAsLesseeScheduleOfMinimumPaymentsOfInitiatedAndRemainingLeaseAgreementsWithNoncancelableClauses
1718	Disclosure of finance lease and operating lease by lessee [table]	Table	*	*	ifrs-full:DisclosureOfFinanceLeaseAndOperatingLeaseByLesseeTable
1719	Past due status [axis]	Axis			ifrs-full:PastDueStatusAxis
1720	Past due status [member]	Member			ifrs-full:PastDueStatusMember
1721	Current [member]	Member			ifrs-full:CurrentMember
1722	Non-current [Member]	Member			itub:NonCurrentMember
1723	Maturity [axis]	Axis			ifrs-full:MaturityAxis
1724	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
1725	Current [Member]	Member			ifrs-full:NotLaterThanOneYearMember
1726	1-5 years [Member]	Member			ifrs-full:LaterThanOneYearAndNotLaterThanFiveYearsMember
1727	Over 5 years [Member]	Member			ifrs-full:LaterThanFiveYearsMember
1728	Disclosure of finance lease and operating lease by lessee [line items]	LineItems			ifrs-full:DisclosureOfFinanceLeaseAndOperatingLeaseByLesseeLineItems
1729	Future minimum payments, with non-cancelable clauses	Concept (Monetary)	As Of	Debit	ifrs-full:ExpectedFutureMinimumSubleasePaymentsReceivableUnderNoncancellableSubleasesClassifiedAsOperatingLease
1730	1137 - Disclosure - Fixed Assets - Summary of Fixed Assets (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFixedAssetsSummaryOfFixedAssets
1731	Disclosure of detailed information about property, plant and equipment [table]	Table	*	*	ifrs-full:DisclosureOfPropertyPlantAndEquipmentTable
1732	Classes of assets [axis]	Axis			ifrs-full:ClassesOfAssetsAxis
1733	Assets [member]	Member			ifrs-full:ClassesOfAssetsMember
1734	Real estate in use [Member]	Member			itub:RealEstateInUseMember
1735	Other fixed assets [Member]	Member			itub:OtherFixedAssetsMember
1736	Range [axis]	Axis			ifrs-full:RangeAxis
1737	Ranges [member]	Member			ifrs-full:RangesMember
1738	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
1739	Top of range [member]	Member			ifrs-full:TopOfRangeMember
1740	Classes of property, plant and equipment [axis]	Axis			ifrs-full:ClassesOfPropertyPlantAndEquipmentAxis
1741	Property, plant and equipment [member]	Member			ifrs-full:PropertyPlantAndEquipmentMember
1742	Fixed assets under construction [Member]	Member			ifrs-full:ConstructionInProgressMember
1743	Land [member]	Member			ifrs-full:LandMember
1744	Buildings [member]	Member			ifrs-full:BuildingsMember
1745	Improvements [Member]	Member			ifrs-full:LeaseholdImprovementsMember
1746	Installations [Member]	Member			itub:InstallationsMember
1747	Furniture and Equipment [Member]	Member			itub:FurnitureAndEquipmentMember
1748	EDP systems [Member]	Member			ifrs-full:ComputerEquipmentMember
1749	Other (communication,security and transportation) [Member]	Member			ifrs-full:OtherPropertyPlantAndEquipmentMember
1750	Carrying amount, accumulated depreciation, amortisation and impairment and gross carrying amount [axis]	Axis			ifrs-full:CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis
1751	Carrying amount [member]	Member			ifrs-full:CarryingAmountMember
1752	Cost [Member]	Member			ifrs-full:GrossCarryingAmountMember
1753	Depreciation and Amortization [Member]	Member			ifrs-full:AccumulatedDepreciationAndAmortisationMember
1754	Impairment [Member]	Member			ifrs-full:AccumulatedImpairmentMember
1755	Disclosure of detailed information about property, plant and equipment [line items]	LineItems			ifrs-full:DisclosureOfPropertyPlantAndEquipmentLineItems
1756	Beginning balance	Concept (Monetary)	As Of	Debit	ifrs-full:PropertyPlantAndEquipment
1757	Annual depreciation rates	Concept (Text/String)	For Period		ifrs-full:UsefulLivesOrDepreciationRatesPropertyPlantAndEquipment
1758	Acquisitions	Concept (Monetary)	For Period	Debit	ifrs-full:AcquisitionsThroughBusinessCombinationsPropertyPlantAndEquipment
1759	Accumulated depreciation	Concept (Monetary)	For Period		ifrs-full:DepreciationPropertyPlantAndEquipment
1760	Additions/ assumptions	Concept (Monetary)	For Period	Debit	ifrs-full:AdditionsOtherThanThroughBusinessCombinationsPropertyPlantAndEquipment
1761	Book value	Concept (Monetary)	As Of	Debit	ifrs-full:PropertyPlantAndEquipment
1762	Reversals	Concept (Monetary)	For Period		ifrs-full:ReversalOfImpairmentLossRecognisedInOtherComprehensiveIncomePropertyPlantAndEquipment
1763	Disposal	Concept (Monetary)	For Period	Credit	ifrs-full:DisposalsPropertyPlantAndEquipment
1764	Exchange variation	Concept (Monetary)	For Period	Debit	ifrs-full:IncreaseDecreaseThroughNetExchangeDifferencesPropertyPlantAndEquipment
1765	Transfers	Concept (Monetary)	For Period	Debit	ifrs-full:IncreaseDecreaseThroughTransfersFromConstructionInProgressPropertyPlantAndEquipment
1766	Other	Concept (Monetary)	For Period	Debit	ifrs-full:IncreaseDecreaseThroughOtherChangesPropertyPlantAndEquipment
1767	Ending balance	Concept (Monetary)	As Of	Debit	ifrs-full:PropertyPlantAndEquipment
1768	1138 - Disclosure - Fixed Assets - Summary of Fixed Assets (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFixedAssetsSummaryOfFixedAssetsParenthetical
1769	Implied Table	Table	*	*	implied:Table
1770	Disclosure of detailed information about property, plant and equipment [abstract]	Abstract			ifrs-full:DisclosureOfPropertyPlantAndEquipmentAbstract
1771	Contractual commitments for purchase of fixed assets	Concept (Monetary)	As Of	Credit	ifrs-full:ContractualCommitmentsForAcquisitionOfPropertyPlantAndEquipment
1772	EDP systems related to attached real estate	Concept (Monetary)	As Of	Debit	ifrs-full:PropertyPlantAndEquipmentPledgedAsSecurity
1773	1139 - Disclosure - Intangible Assets - Summary of Intangible Assets (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureIntangibleAssetsSummaryOfIntangibleAssets
1774	Disclosure of detailed information about intangible assets [table]	Table	*	*	ifrs-full:DisclosureOfIntangibleAssetsTable
1775	Business combinations [axis]	Axis			ifrs-full:BusinessCombinationsAxis
1776	Entity's total for business combinations [member]	Member			ifrs-full:EntitysTotalForBusinessCombinationsMember
1777	Acquisition of right to credit payroll [Member]	Member			itub:CreditPayrollRightsAcquisitionMember
1778	Acquisition of software [Member]	Member			itub:SoftwareAcquisitionMember
1779	Range [axis]	Axis			ifrs-full:RangeAxis
1780	Ranges [member]	Member			ifrs-full:RangesMember
1781	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
1782	Top of range [member]	Member			ifrs-full:TopOfRangeMember
1783	Classes of intangible assets other than goodwill [axis]	Axis			ifrs-full:ClassesOfIntangibleAssetsOtherThanGoodwillAxis
1784	Intangible assets other than goodwill [member]	Member			ifrs-full:IntangibleAssetsOtherThanGoodwillMember
1785	Association for the promotion and offer of financial products and service [Member]	Member			itub:PromotionAndOfferOfFinancialProductsAndServiceMember
1786	Development of software [Member]	Member			ifrs-full:IntangibleAssetsUnderDevelopmentMember
1787	Other intangible assets [member]	Member			ifrs-full:OtherIntangibleAssetsMember
1788	Carrying amount, accumulated depreciation, amortisation and impairment and gross carrying amount [axis]	Axis			ifrs-full:CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis
1789	Carrying amount [member]	Member			ifrs-full:CarryingAmountMember
1790	Cost [Member]	Member			ifrs-full:GrossCarryingAmountMember
1791	Depreciation and Amortization [Member]	Member			ifrs-full:AccumulatedDepreciationAndAmortisationMember
1792	Impairment [Member]	Member			ifrs-full:AccumulatedImpairmentMember
1793	Disclosure of detailed information about intangible assets [line items]	LineItems			ifrs-full:DisclosureOfIntangibleAssetsLineItems
1794	Book value	Concept (Monetary)	As Of	Debit	ifrs-full:IntangibleAssetsOtherThanGoodwill
1795	Amortization rates p.a.	Concept (Percent)	For Period		itub:FiniteLivedIntangibleAssetsAmortizationRate
1796	Beginning balance	Concept (Monetary)	As Of	Debit	ifrs-full:IntangibleAssetsOtherThanGoodwill
1797	Acquisitions	Concept (Monetary)	For Period	Debit	ifrs-full:AcquisitionsThroughBusinessCombinationsIntangibleAssetsOtherThanGoodwill
1798	Amortization expense	Concept (Monetary)	For Period		ifrs-full:AmortisationIntangibleAssetsOtherThanGoodwill
1799	Additions / assumptions	Concept (Monetary)	For Period	Debit	ifrs-full:AdditionsOtherThanThroughBusinessCombinationsIntangibleAssetsOtherThanGoodwill
1800	Reversals	Concept (Monetary)	For Period		ifrs-full:ReversalOfImpairmentLossRecognisedInProfitOrLossIntangibleAssetsOtherThanGoodwill
1801	Terminated agreements / write off	Concept (Monetary)	For Period	Credit	ifrs-full:DisposalsAndRetirementsIntangibleAssetsOtherThanGoodwill
1802	Exchange variation	Concept (Monetary)	For Period	Debit	ifrs-full:IncreaseDecreaseThroughNetExchangeDifferencesIntangibleAssetsOtherThanGoodwill
1803	Other	Concept (Monetary)	For Period	Debit	ifrs-full:ChangesInIntangibleAssetsOtherThanGoodwill
1804	Ending balance	Concept (Monetary)	As Of	Debit	ifrs-full:IntangibleAssetsOtherThanGoodwill
1805	1140 - Disclosure - Intangible Assets - Summary of Intangible Assets (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureIntangibleAssetsSummaryOfIntangibleAssetsParenthetical
1806	Implied Table	Table	*	*	implied:Table
1807	Disclosure of detailed information about intangible assets [abstract]	Abstract			ifrs-full:DisclosureOfIntangibleAssetsAbstract
1808	Contractual commitments for purchase of new intangible assets	Concept (Monetary)	As Of	Credit	ifrs-full:ContractualCommitmentsForAcquisitionOfIntangibleAssets
1809	1141 - Disclosure - Deposits - Summary of Breakdown of Deposits (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureDepositsSummaryOfBreakdownOfDeposits
1810	Disclosure Of Deposits [Table]	Table	*	*	itub:DisclosureOfDepositsTable
1811	Categories of financial liabilities [axis]	Axis			ifrs-full:CategoriesOfFinancialLiabilitiesAxis
1812	Financial liabilities, category [member]	Member			ifrs-full:FinancialLiabilitiesCategoryMember
1813	Interest-bearing deposits [Member]	Member			itub:InterestBearingDeposits1Member
1814	Time deposits [Member]	Member			itub:TimeDepositsMember
1815	Interbank deposits [Member]	Member			itub:InterbankDepositsMember
1816	Savings deposits [Member]	Member			itub:SavingDepositsMember
1817	Non-interest bearing deposits [Member]	Member			itub:NonInterestBearingDepositsMember
1818	Demand deposits [Member]	Member			itub:DemandDeposits1Member
1819	Other [Member]	Member			itub:OtherDepositsMember
1820	Disclosure of deposits [Line Items]	LineItems			itub:DisclosureOfDepositsLineItems
1821	Current	Concept (Monetary)	As Of	Credit	ifrs-full:CurrentDepositsFromCustomers
1822	Non-current	Concept (Monetary)	As Of	Credit	ifrs-full:NoncurrentDepositsFromCustomers
1823	Total	Concept (Monetary)	As Of	Credit	ifrs-full:DepositsFromCustomers
1824	1142 - Disclosure - Financial Liabilities Held for Trading - Summary of Financial Liabilities Held for Trading (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFinancialLiabilitiesHeldForTradingSummaryOfFinancialLiabilitiesHeldForTrading
1825	Disclosure of financial liabilities held for trading [Table]	Table	*	*	itub:DisclosureOfFinancialLiabilitiesHeldForTradingTable
1826	Types of financial liabilities [axis]	Axis			ifrs-full:TypesOfFinancialLiabilitiesAxis
1827	Financial liabilities, type [member]	Member			ifrs-full:FinancialLiabilitiesTypeMember
1828	Shares held for trading [member]	Member			itub:SharesHeldForTradingMember
1829	Debt Securities Held For Trading [Member]	Member			itub:DebtSecuritiesHeldForTradingMember
1830	Disclosure of financial liabilities held for trading [Line Items]	LineItems			itub:DisclosureOfFinancialLiabilitiesHeldForTradingLineItems
1831	Structured notes	Abstract			itub:StructuredNotesAbstract
1832	Financial liabilities held for trading	Concept (Monetary)	As Of	Credit	ifrs-full:FinancialLiabilitiesAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
1833	1143 - Disclosure - Financial Liabilities Held for Trading - Summary of Fair Value of Financial Liabilities Held for Trading by Maturity (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFinancialLiabilitiesHeldForTradingSummaryOfFairValueOfFinancialLiabilitiesHeldForTradingByMaturity
1834	Disclosure of maturity analysis for non-derivative financial liabilities [table]	Table	*	*	ifrs-full:DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesTable
1835	Maturity [axis]	Axis			ifrs-full:MaturityAxis
1836	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
1837	Current [Member]	Member			ifrs-full:NotLaterThanOneYearMember
1838	1-5 years [Member]	Member			ifrs-full:LaterThanOneYearAndNotLaterThanFiveYearsMember
1839	From five to ten years [Member]	Member			ifrs-full:LaterThanFiveYearsAndNotLaterThanTenYearsMember
1840	After ten years [Member]	Member			ifrs-full:LaterThanTenYearsMember
1841	Disclosure of maturity analysis for non-derivative financial liabilities [line items]	LineItems			ifrs-full:DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems
1842	Current	Concept (Monetary)	As Of	Credit	ifrs-full:CurrentFinancialLiabilitiesAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
1843	Non-current	Concept (Monetary)	As Of	Credit	ifrs-full:NoncurrentFinancialLiabilitiesAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
1844	Total	Concept (Monetary)	As Of	Credit	ifrs-full:FinancialLiabilitiesAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
1845	1144 - Disclosure - Securities Sold Under Repurchase Agreements and Interbank and Institutional Market Debts - Summary of Securities Sold Under Repurchase Agreements and Interbank Market Debt (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureSecuritiesSoldUnderRepurchaseAgreementsAndInterbankAndInstitutionalMarketDebtsSummaryOfSecuritiesSoldUnderRepurchaseAgreementsAndInterbankMarketDebt
1846	Disclosure Of Repurchase Agreements [Table]	Table	*	*	itub:DisclosureOfRepurchaseAgreementsTable
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1849	Current [member]	Member			ifrs-full:CurrentMember
1850	Non-current [Member]	Member			itub:NonCurrentMember
1851	Classes of financial liabilities [axis]	Axis			ifrs-full:ClassesOfFinancialLiabilitiesAxis
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1855	Real estate credit bills [Member]	Member			itub:RealEstateCreditBillsMember
1856	Agribusiness credit bills [Member]	Member			itub:AgribusinessCreditBillsMember
1857	Financial credit bills [Member]	Member			itub:FinancialCreditBillsMember
1858	Import and export financing [Member]	Member			itub:CreditFacilitiesAvailableForFinancingOfImportsAndExportsMember
1859	On-lending - domestic [Member]	Member			itub:OnlendingDomesticMember
1860	Liabilities from transactions related to credit assignments [Member]	Member			itub:LiabilitiesFromTransactionsRelatedToCreditAssignmentsMember
1861	Disclosure Of Repurchase Agreements [Line Items]	LineItems			itub:DisclosureOfRepurchaseAgreementsLineItems
1862	Securities sold under repurchase agreements	Concept (Monetary)	As Of	Credit	ifrs-full:RepurchaseAgreementsAndCashCollateralOnSecuritiesLent
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1864	1145 - Disclosure - Securities Sold Under Repurchase Agreements and Interbank and Institutional Market Debts - Summary of Securities Sold Under Repurchase Agreements and Interbank Market Debt (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureSecuritiesSoldUnderRepurchaseAgreementsAndInterbankAndInstitutionalMarketDebtsSummaryOfSecuritiesSoldUnderRepurchaseAgreementsAndInterbankMarketDebtParenthetical
1865	Implied Table	Table	*	*	implied:Table
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1869	Disclosure Of Repurchase Agreements [Table]	Table	*	*	itub:DisclosureOfRepurchaseAgreementsTable
1870	Geographical areas [axis]	Axis			ifrs-full:GeographicalAreasAxis
1871	Geographical areas [member]	Member			ifrs-full:GeographicalAreasMember
1872	Brazil [Member]	Member			country:BR
1873	Foreign [Member]	Member			ifrs-full:ForeignCountriesMember
1874	Range [axis]	Axis			ifrs-full:RangeAxis
1875	Ranges [member]	Member			ifrs-full:RangesMember
1876	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
1877	Top of range [member]	Member			ifrs-full:TopOfRangeMember
1878	Classes of financial liabilities [axis]	Axis			ifrs-full:ClassesOfFinancialLiabilitiesAxis
1879	Financial liabilities, class [member]	Member			ifrs-full:FinancialLiabilitiesMember
1880	Real estate credit bills [Member]	Member			itub:RealEstateCreditBillsMember
1881	Financial credit bills [Member]	Member			itub:FinancialCreditBillsMember
1882	Agribusiness credit bills [Member]	Member			itub:AgribusinessCreditBillsMember
1883	Import and export financing [Member]	Member			itub:CreditFacilitiesAvailableForFinancingOfImportsAndExportsMember
1884	On-lending - domestic [Member]	Member			itub:OnlendingDomesticMember
1885	Liabilities from transactions related to credit assignments [Member]	Member			itub:LiabilitiesFromTransactionsRelatedToCreditAssignmentsMember
1886	Disclosure Of Repurchase Agreements [Line Items]	LineItems			itub:DisclosureOfRepurchaseAgreementsLineItems
1887	Securities sold under repurchase agreements	Concept (Percent)	For Period		itub:SecuritiesSoldUnderAgreementsToRepurchaseInterestRate
1888	Percentage of interest on interbank market debt	Concept (Percent)	For Period		itub:PercentageOfInterestOnInterbankMarketDebt
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1890	Disclosure Of Repurchase Agreements [Table]	Table	*	*	itub:DisclosureOfRepurchaseAgreementsTable
1891	Past due status [axis]	Axis			ifrs-full:PastDueStatusAxis
1892	Past due status [member]	Member			ifrs-full:PastDueStatusMember
1893	Current [member]	Member			ifrs-full:CurrentMember
1894	Non-current [Member]	Member			itub:NonCurrentMember
1895	Classes of financial liabilities [axis]	Axis			ifrs-full:ClassesOfFinancialLiabilitiesAxis
1896	Financial liabilities, class [member]	Member			ifrs-full:FinancialLiabilitiesMember
1897	Subordinated debt [Member]	Member			us-gaap:SubordinatedDebtMember
1898	Foreign borrowing through securities [Member]	Member			itub:ForeignBorrowingThroughSecuritiesMember
1899	Structured Operations Certificates [Member]	Member			itub:StructuredOperationsCertificatesMember
1900	Disclosure Of Repurchase Agreements [Line Items]	LineItems			itub:DisclosureOfRepurchaseAgreementsLineItems
1901	Institutional market debt	Concept (Monetary)	As Of	Credit	ifrs-full:DebtSecurities
1902	1148 - Disclosure - Securities Sold Under Repurchase Agreements and Interbank and Institutional Market Debts - Summary of Breakdown of Funds Obtained in Institutional Markets (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureSecuritiesSoldUnderRepurchaseAgreementsAndInterbankAndInstitutionalMarketDebtsSummaryOfBreakdownOfFundsObtainedInInstitutionalMarketsParenthetical
1903	Disclosure Of Repurchase Agreements [Table]	Table	*	*	itub:DisclosureOfRepurchaseAgreementsTable
1904	Classes of financial liabilities [axis]	Axis			ifrs-full:ClassesOfFinancialLiabilitiesAxis
1905	Financial liabilities, class [member]	Member			ifrs-full:FinancialLiabilitiesMember
1906	Structured Operations Certificates [Member]	Member			itub:StructuredOperationsCertificatesMember
1907	Reference Equity [Member]	Member			itub:ReferenceEquityMember
1908	Disclosure Of Repurchase Agreements [Line Items]	LineItems			itub:DisclosureOfRepurchaseAgreementsLineItems
1909	Institutional market debt	Concept (Monetary)	As Of	Credit	ifrs-full:DebtSecurities
1910	Market value of fund	Concept (Monetary)	As Of	Credit	itub:FairValueDebtSecurities
1911	1149 - Disclosure - Securities Sold Under Repurchase Agreements and Interbank and Institutional Market Debts - Summary of Interest Rate for Each Operations (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureSecuritiesSoldUnderRepurchaseAgreementsAndInterbankAndInstitutionalMarketDebtsSummaryOfInterestRateForEachOperations
1912	Disclosure Of Repurchase Agreements [Table]	Table	*	*	itub:DisclosureOfRepurchaseAgreementsTable
1913	Geographical areas [axis]	Axis			ifrs-full:GeographicalAreasAxis
1914	Geographical areas [member]	Member			ifrs-full:GeographicalAreasMember
1915	Brazil [Member]	Member			country:BR
1916	Foreign [Member]	Member			ifrs-full:ForeignCountriesMember
1917	Classes of financial liabilities [axis]	Axis			ifrs-full:ClassesOfFinancialLiabilitiesAxis
1918	Financial liabilities, class [member]	Member			ifrs-full:FinancialLiabilitiesMember
1919	Subordinated debt [Member]	Member			us-gaap:SubordinatedDebtMember
1920	Foreign borrowing through securities [Member]	Member			itub:ForeignBorrowingThroughSecuritiesMember
1921	Structured Operations Certificates [Member]	Member			itub:StructuredOperationsCertificatesMember
1922	Range [axis]	Axis			ifrs-full:RangeAxis
1923	Ranges [member]	Member			ifrs-full:RangesMember
1924	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
1925	Top of range [member]	Member			ifrs-full:TopOfRangeMember
1926	Disclosure Of Repurchase Agreements [Line Items]	LineItems			itub:DisclosureOfRepurchaseAgreementsLineItems
1927	Interest rate for each operations	Concept (Percent)	As Of		ifrs-full:BorrowingsInterestRate
1928	1150 - Disclosure - Other assets and liabilities - Summary of Other Assets (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureOtherAssetsAndLiabilitiesSummaryOfOtherAssets
1929	Disclosure of Financial Assets [Table]	Table	*	*	ifrs-full:DisclosureOfFinancialAssetsTable
1930	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
1931	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
1932	Receivables from credit card issuers [Member]	Member			itub:ReceivablesFromCreditCardIssuersMember
1933	Insurance and reinsurance operations [Member]	Member			itub:InsuranceAndReinsuranceOperationsMember
1934	Deposits in guarantee for contingent liabilities [Member]	Member			itub:DepositsInGuaranteeForContingentLiabilitiesMember
1935	Deposits in guarantee for foreign borrowing program [Member]	Member			itub:DepositsInGuaranteeForForeignBorrowingProgramMember
1936	Negotiation and intermediation of securities [Member]	Member			itub:NegotiationAndIntermediationOfSecuritiesMember
1937	Receivables from reimbursement of contingent liabilities [Member]	Member			itub:ReceivablesFromReimbursementOfContingentLiabilitiesMember
1938	Receivables from services provided [Member]	Member			itub:ReceivablesFromServicesProvidedMember
1939	Amounts receivable from FCVS salary variations compensation fund [Member]	Member			itub:AmountsReceivableFromFcvsSalaryVariationsCompensationFundMember
1940	Operations without credit granting characteristics [Member]	Member			itub:OperationsWithoutCreditGrantingCharacteristicsMember
1941	Prepaid expenses [Member]	Member			itub:PrepaidExpensesMember
1942	Retirement plan assets [Member]	Member			itub:RetirementPlanAssetsMember
1943	Sundry domestic [Member]	Member			itub:SundryDomesticMember
1944	Premiums from loan operations [Member]	Member			itub:PremiumsFromLoanOperationsMember
1945	Sundry Foreign [Member]	Member			itub:SundryForeignMember
1946	Other non financial assets [Member]	Member			itub:OtherNonFinancialAssetsMember
1947	Classes of assets [axis]	Axis			ifrs-full:ClassesOfAssetsAxis
1948	Assets [member]	Member			ifrs-full:ClassesOfAssetsMember
1949	Other financial asset [Member]	Member			itub:OtherFinancialAssetMember
1950	Disclosure of Financial Assets [Line Items]	LineItems			ifrs-full:DisclosureOfFinancialAssetsLineItems
1951	Other non-financial assets, Current	Concept (Monetary)	As Of	Debit	ifrs-full:OtherCurrentNonfinancialAssets
1952	Other non-financial assets, Non-current	Concept (Monetary)	As Of	Debit	ifrs-full:OtherNoncurrentNonfinancialAssets
1953	Other non-financial assets, Total	Concept (Monetary)	As Of	Debit	ifrs-full:OtherNonfinancialAssets
1954	Other financial assets, Current	Concept (Monetary)	As Of	Debit	ifrs-full:OtherCurrentFinancialAssets
1955	Other financial assets, Non-current	Concept (Monetary)	As Of	Debit	ifrs-full:OtherNoncurrentFinancialAssets
1956	Other financial assets, Total	Concept (Monetary)	As Of	Debit	ifrs-full:OtherFinancialAssets
1957	Impairment expense	Concept (Monetary)	For Period	Debit	ifrs-full:ImpairmentLossOnFinancialAssets
1958	1151 - Disclosure - Other assets and liabilities - Summary of Other Liabilities (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureOtherAssetsAndLiabilitiesSummaryOfOtherLiabilities
1959	Disclosure of financial liabilities [table]	Table	*	*	ifrs-full:DisclosureOfFinancialLiabilitiesTable
1960	Classes of financial liabilities [axis]	Axis			ifrs-full:ClassesOfFinancialLiabilitiesAxis
1961	Financial liabilities, class [member]	Member			ifrs-full:FinancialLiabilitiesMember
1962	Credit card operations [Member]	Member			itub:CreditCardOperationsMember
1963	Foreign exchange portfolio [Member]	Member			itub:ForeignExchangePortfolioMember
1964	Negotiation and intermediation of securities [Member]	Member			itub:NegotiationAndIntermediationOfSecuritiesMember
1965	Finance lease liabilities [Member]	Member			itub:FinanceLeaseLiabilitiesMember
1966	Funds from consortia participants [Member]	Member			itub:FundsFromConsortiaParticipantsMember
1967	Other financials liabilities [Member]	Member			itub:OtherFinancialsLiabilitiesMember
1968	Collection and payment of taxes and contributions [Member]	Member			itub:CollectionAndPaymentOfTaxesAndContributionsMember
1969	Domestic sundry creditors [Member]	Member			itub:DomesticSundryCreditorsMember
1970	Funds in transit [Member]	Member			itub:FundsInTransitMember
1971	Provision for sundry payments [Member]	Member			itub:ProvisionForSundryPaymentsMember
1972	Social and statutory [Member]	Member			itub:SocialAndStatutoryMember
1973	Related to insurance operations [Member]	Member			itub:RelatedToInsuranceOperationsMember
1974	Liabilities for official agreements and rendering of payment services [Member]	Member			itub:LiabilitiesForOfficialAgreementsAndRenderingOfPaymentServicesMember
1975	Provision for retirement plan benefits [Member]	Member			itub:ProvisionForRetirementPlanBenefitsMember
1976	Personnel provision [Member]	Member			itub:PersonnelProvisionMember
1977	Provision for health insurance [Member]	Member			itub:ProvisionForHealthInsuranceMember
1978	Provision for Citibank integration expenditures [member]	Member			itub:ProvisionForCitibankIntegrationExpendituresMember
1979	Deferred income [Member]	Member			itub:DeferredIncomeMember
1980	Other non-financial liabilities [Member]	Member			itub:OtherNonfinancialLiabilitiesMember
1981	Disclosure of financial liabilities [line items]	LineItems			ifrs-full:DisclosureOfFinancialLiabilitiesLineItems
1982	Other non-financial liabilities, Current	Concept (Monetary)	As Of	Credit	ifrs-full:OtherCurrentNonfinancialLiabilities
1983	Other non-financial liabilities, Non-current	Concept (Monetary)	As Of	Credit	ifrs-full:OtherNoncurrentNonfinancialLiabilities
1984	Other non-financial liabilities, Total	Concept (Monetary)	As Of	Credit	ifrs-full:OtherNonfinancialLiabilities
1985	Other financial liabilities, Current	Concept (Monetary)	As Of	Credit	ifrs-full:OtherCurrentFinancialLiabilities
1986	Other financial liabilities, Non-current	Concept (Monetary)	As Of	Credit	ifrs-full:OtherNoncurrentFinancialLiabilities
1987	Other financial liabilities, Total	Concept (Monetary)	As Of	Credit	ifrs-full:OtherFinancialLiabilities
1988	1152 - Disclosure - Stockholders' equity - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureStockholdersEquityAdditionalInformation
1989	Disclosure of classes of share capital [table]	Table	*	*	ifrs-full:DisclosureOfClassesOfShareCapitalTable
1990	Classes of share capital [axis]	Axis			ifrs-full:ClassesOfShareCapitalAxis
1991	Share capital [member]	Member			ifrs-full:ClassesOfShareCapitalMember
1992	Preference shares [member]	Member			ifrs-full:PreferenceSharesMember
1993	Ordinary shares [member]	Member			ifrs-full:OrdinarySharesMember
1994	Range [axis]	Axis			ifrs-full:RangeAxis
1995	Ranges [member]	Member			ifrs-full:RangesMember
1996	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
1997	Geographical areas [axis]	Axis			ifrs-full:GeographicalAreasAxis
1998	Geographical areas [member]	Member			ifrs-full:GeographicalAreasMember
1999	Country of domicile [member]	Member			ifrs-full:CountryOfDomicileMember
2000	Foreign [Member]	Member			ifrs-full:ForeignCountriesMember
2001	Disclosure of classes of share capital [line items]	LineItems			ifrs-full:DisclosureOfClassesOfShareCapitalLineItems
2002	Increase of subscribed and paid-up capital	Concept (Monetary)	For Period	Credit	itub:IncreaseInAdditionalPaidInCapitalAgainstEquityReserves
2003	Bonus shares reserve	Concept (Percent)	For Period		itub:BonusSharesReservePercentage
2004	Number of capital stock increased	Concept (Shares)	For Period		itub:IncreaseInCapitalThroughIssuanceOfStock
2005	Cancellation of Shares	Concept (Shares)	For Period		itub:CancellationOfTreasuryStockShares
2006	Total share capital	Concept (Shares)	As Of		ifrs-full:NumberOfSharesIssued
2007	Par value	Concept (Share)	As Of		ifrs-full:ParValuePerShare
2008	Number of common stock	Concept (Shares)	For Period		itub:NumberOfCommonSharesIssued
2009	Number of preferred stock	Concept (Shares)	For Period		itub:NumberOfPreferredSharesIssued
2010	Capital stock	Concept (Monetary)	As Of	Credit	ifrs-full:IssuedCapital
2011	Annual mandatory dividend rate	Concept (Percent)	For Period		itub:DividendRatePercentage
2012	Annual minimum priority dividend	Concept (Share)	For Period		itub:PaymentOfAnnualDividendPerShare
2013	1153 - Disclosure - Stockholders' equity - Summary of Change in Shares of Paid-in Capital and Reconciliation of Balances (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureStockholdersEquitySummaryOfChangeInSharesOfPaidinCapitalAndReconciliationOfBalances
2014	Disclosure of classes of share capital [table]	Table	*	*	ifrs-full:DisclosureOfClassesOfShareCapitalTable
2015	Classes of share capital [axis]	Axis			ifrs-full:ClassesOfShareCapitalAxis
2016	Share capital [member]	Member			ifrs-full:ClassesOfShareCapitalMember
2017	Ordinary shares [member]	Member			ifrs-full:OrdinarySharesMember
2018	Preference shares [member]	Member			ifrs-full:PreferenceSharesMember
2019	Components of equity [axis]	Axis			ifrs-full:ComponentsOfEquityAxis
2020	Equity [member]	Member			ifrs-full:EquityMember
2021	Treasury shares [member]	Member			ifrs-full:TreasurySharesMember
2022	Geographical areas [axis]	Axis			ifrs-full:GeographicalAreasAxis
2023	Geographical areas [member]	Member			ifrs-full:GeographicalAreasMember
2024	Brazil [Member]	Member			country:BR
2025	Foreign [Member]	Member			ifrs-full:ForeignCountriesMember
2026	Disclosure of classes of share capital [line items]	LineItems			ifrs-full:DisclosureOfClassesOfShareCapitalLineItems
2027	Outstanding shares	Concept (Shares)	As Of		ifrs-full:NumberOfSharesOutstanding
2028	Treasury shares, value	Concept (Monetary)	As Of	Debit	ifrs-full:TreasuryShares
2029	Purchase of shares	Concept (Monetary)	For Period	Debit	ifrs-full:PurchaseOfTreasuryShares
2030	Exercised options - granting of stock options	Concept (Monetary)	For Period	Credit	itub:TreasurySharesExercisedOptionGranted
2031	Disposals - stock option plan	Concept (Monetary)	For Period	Credit	ifrs-full:SaleOrIssueOfTreasuryShares
2032	Cancellation of Shares - Meeting of the Board of Directors December 15, 2017	Concept (Monetary)	For Period	Credit	ifrs-full:CancellationOfTreasuryShares
2033	Treasury shares, value	Concept (Monetary)	As Of	Debit	ifrs-full:TreasuryShares
2034	Shares of capital stock, beginning balance	Concept (Shares)	As Of		ifrs-full:NumberOfSharesIssued
2035	Cancellation of Shares	Concept (Shares)	For Period		itub:CancellationOfTreasuryStockShares
2036	Bonus Shares-ESM of 09/14/2016-Carried out at 09/23/2016	Concept (Shares)	For Period		itub:NumberOfBonusIssueOfOrdinaryShares
2037	Shares of capital stock, ending balance	Concept (Shares)	As Of		ifrs-full:NumberOfSharesIssued
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2042	Cancellation of Shares	Concept (Shares)	For Period		itub:CancellationOfTreasuryStockShares
2043	Bonus Shares-ESM of 09/14/2016-Carried out at 09/23/2016	Concept (Shares)	For Period		itub:NumberOfBonusIssueOfTreasuryShares
2044	Treasury shares, ending balance	Concept (Shares)	As Of		itub:NumberOfTreasuryShares
2045	1154 - Disclosure - Stockholders' equity - Summary of Cost of Shares Purchased and Average Cost of Treasury Shares and Market Price (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureStockholdersEquitySummaryOfCostOfSharesPurchasedAndAverageCostOfTreasurySharesAndMarketPrice
2046	Disclosure of classes of share capital [table]	Table	*	*	ifrs-full:DisclosureOfClassesOfShareCapitalTable
2047	Classes of share capital [axis]	Axis			ifrs-full:ClassesOfShareCapitalAxis
2048	Share capital [member]	Member			ifrs-full:ClassesOfShareCapitalMember
2049	Ordinary shares [member]	Member			ifrs-full:OrdinarySharesMember
2050	Preference shares [member]	Member			ifrs-full:PreferenceSharesMember
2051	Range [axis]	Axis			ifrs-full:RangeAxis
2052	Ranges [member]	Member			ifrs-full:RangesMember
2053	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
2054	Weighted average [member]	Member			ifrs-full:WeightedAverageMember
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2056	Disclosure of classes of share capital [line items]	LineItems			ifrs-full:DisclosureOfClassesOfShareCapitalLineItems
2057	Cost per share	Concept (Share)	For Period		itub:SharePricePerShare
2058	Average cost	Concept (Share)	For Period		itub:AverageSharePrice
2059	Market price per share	Concept (Share)	As Of		itub:MarketValuePricePerShare
2060	1155 - Disclosure - Shareholders' equity - Summary of Calculation of Dividends and Interest on Capital (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureShareholdersEquitySummaryOfCalculationOfDividendsAndInterestOnCapital
2061	Implied Table	Table	*	*	implied:Table
2062	Disclosure of Dividends [abstract]	Abstract			itub:DisclosureOfDividendsAbstract
2063	Statutory net income	Concept (Monetary)	As Of	Credit	ifrs-full:StatutoryReserve
2064	Legal reserve	Concept (Monetary)	As Of	Credit	itub:LegalReserve
2065	Dividend calculation basis	Concept (Monetary)	As Of	Credit	itub:DividendCalculationBasis
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2067	Dividends and Interest on Capital Paid / Provided for / Identified	Concept (Monetary)	As Of	Credit	ifrs-full:DividendPayables
2068	1156 - Disclosure - Stockholders' Equity - Schedule of Stockholders' Compensation (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureStockholdersEquityScheduleOfStockholdersCompensation
2069	Disclosure of classes of share capital [table]	Table	*	*	ifrs-full:DisclosureOfClassesOfShareCapitalTable
2070	Classes of liabilities [axis]	Axis			ifrs-full:ClassesOfLiabilitiesAxis
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2073	Interest on Capital Two [Member]	Member			itub:InterestOnCapitalTwoMember
2074	Disclosure of classes of share capital [line items]	LineItems			ifrs-full:DisclosureOfClassesOfShareCapitalLineItems
2075	Paid / prepaid, Gross	Concept (Monetary)	For Period	Debit	itub:DividendsPaidAndPrepaidGross
2076	Dividends - 11 monthly installments, Gross	Concept (Monetary)	For Period	Debit	itub:DividendsPaidGross
2077	Interest on capital, Gross	Concept (Monetary)	For Period	Debit	itub:InterestOnCapitalPaidAndPrepaidGross
2078	Provided for (Recorded in Other Liabilities), Gross	Concept (Monetary)	For Period	Credit	itub:ProvidedForRecordedInOtherLiabilitiesGross
2079	Dividends - 1 monthly installment, Gross	Concept (Monetary)	For Period	Credit	itub:DividendsProvidedForRecordedInOtherLiabilitiesGross
2080	Dividends provision-R$ 0.1304, Gross	Concept (Monetary)	For Period	Credit	itub:DividendsProvisionProvidedForRecordedInOtherLiabilitiesGross
2081	Interest on capital	Concept (Monetary)	For Period	Credit	itub:InterestOnCapitalProvidedForRecordedInOtherLiabilitiesGross
2082	Identified in Revenue Reserve ,Gross	Concept (Monetary)	For Period	Debit	itub:IdentifiedInRevenueReserveInStockholdersEquityGross
2083	Total	Concept (Monetary)	For Period	Debit	itub:DividendsOrInterestOnCapitalRecognisedAsDistributionsToOwnersOfParentRelatingToPriorYearsGross
2084	Paid / prepaid, WHT	Concept (Monetary)	For Period	Debit	itub:DividendsPaidAndPrepaidWithholdingTax
2085	Dividends - 11 monthly installments, WHT	Concept (Monetary)	For Period	Debit	itub:DividendsPaidWithholdingTax
2086	Interest on capital, WHT	Concept (Monetary)	For Period	Debit	itub:InterestOnCapitalPaidAndPrepaidWithholdingTax
2087	Provided for (Recorded in Other Liabilities), WHT	Concept (Monetary)	For Period	Credit	itub:ProvidedForRecordedInOtherLiabilitiesWithholdingTax
2088	Dividends - 1 monthly installment, WHT	Concept (Monetary)	For Period	Credit	itub:DividendsProvidedForRecordedInOtherLiabilitiesWithholdingTax
2089	Dividends provision - R$ 0.01304, WHT	Concept (Monetary)	For Period	Credit	itub:DividendsProvisionProvidedForRecordedInOtherLiabilitiesWithholdingTax
2090	Interest on capital, WHT	Concept (Monetary)	For Period	Credit	itub:InterestOnCapitalProvidedForRecordedInOtherLiabilitiesWithholdingTax
2091	Identified in Revenue Reserve In Stockholders' Equity, WHT	Concept (Monetary)	For Period	Debit	itub:IdentifiedInRevenueReserveInStockholdersEquityWithholdingTax
2092	Total ,WHT	Concept (Monetary)	For Period	Debit	itub:DividendsOrInterestOnCapitalRecognisedAsDistributionsToOwnersOfParentRelatingToPriorYearsWithholdingTax
2093	Paid / prepaid	Concept (Monetary)	For Period	Debit	itub:DividendsPaidAndPrepaid
2094	Dividends-11 monthly installments	Concept (Monetary)	For Period	Debit	ifrs-full:DividendsPaid
2095	Interest on capital	Concept (Monetary)	For Period	Debit	itub:InterestOnCapitalPaidAndPrepaid
2096	Provided for (Recorded in Other Liabilities)	Concept (Monetary)	For Period	Credit	itub:ProvidedForRecordedInOtherLiabilities
2097	Dividends-1 monthly installment	Concept (Monetary)	For Period	Credit	itub:DividendsProvidedForRecordedInOtherLiabilities
2098	Dividends provision-R$ 0.1304	Concept (Monetary)	For Period	Credit	itub:DividendsProvisionProvidedForRecordedInOtherLiabilities
2099	Interest on capital	Concept (Monetary)	For Period	Credit	itub:InterestOnCapitalProvidedForRecordedInOtherLiabilities
2100	Identified in Revenue Reserve In Stockholders' Equity	Concept (Monetary)	For Period	Debit	itub:IdentifiedInRevenueReserveInStockholdersEquity
2101	Total	Concept (Monetary)	As Of	Credit	itub:DividendsAndInterestOnShareholderEquityPayable
2102	1157 - Disclosure - Stockholders' Equity - Schedule of Stockholders' Compensation (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureStockholdersEquityScheduleOfStockholdersCompensationParenthetical
2103	Disclosure of classes of share capital [table]	Table	*	*	ifrs-full:DisclosureOfClassesOfShareCapitalTable
2104	Non-adjusting events after reporting period [axis]	Axis			ifrs-full:NonadjustingEventsAfterReportingPeriodAxis
2105	Non-adjusting events after reporting period [member]	Member			ifrs-full:NonadjustingEventsMember
2106	Subsequent Event 1 [member]	Member			itub:SubsequentEvent1Member
2107	Disclosure of classes of share capital [line items]	LineItems			ifrs-full:DisclosureOfClassesOfShareCapitalLineItems
2108	Number of installments	Concept (Integer)	For Period		itub:NumberOfInstalments
2109	Dividend paid per share	Concept (Share)	For Period		ifrs-full:DividendsPaidOrdinarySharesPerShare
2110	Interest on capital paid per share	Concept (Share)	For Period		itub:InterestOnCapitalPaidPerShare
2111	Number of installments	Concept (Integer)	For Period		itub:NumberOfInstalments
2112	Dividend paid per share	Concept (Share)	For Period		ifrs-full:DividendsPaidOrdinarySharesPerShare
2113	Dividends provision per share	Concept (Share)	For Period		itub:DividendsProvisionPerShare
2114	Interest on capital paid per share	Concept (Share)	For Period		itub:InterestOnCapitalPaidPerShare
2115	1158 - Disclosure - Stockholders' Equity - Summary of Appropriated Reserves (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureStockholdersEquitySummaryOfAppropriatedReserves
2116	Disclosure of reserves within equity [table]	Table	*	*	ifrs-full:DisclosureOfReservesWithinEquityTable
2117	Reserves within equity [axis]	Axis			ifrs-full:ReservesWithinEquityAxis
2118	Other reserves [member]	Member			ifrs-full:OtherReservesMember
2119	Premium on subscription of shares [Member]	Member			itub:PremiumOnSubscriptionOfSharesMember
2120	Reserves from tax incentives, restatement of equity securities and other [Member]	Member			itub:ReservesFromTaxIncentivesRestatementOfEquitySecuritiesAndOtherMember
2121	Legal [Member]	Member			us-gaap:LegalReserveMember
2122	Statutory [Member]	Member			ifrs-full:StatutoryReserveMember
2123	Dividends equalization [Member]	Member			itub:DividendsEqualizationMember
2124	Working capital increase [Member]	Member			itub:WorkingCapitalIncreaseMember
2125	Increase in capital of investees [Member]	Member			itub:IncreaseInCapitalOfInvesteesMember
2126	Corporate reorganizations [Member]	Member			itub:CorporateReorganizationsMember
2127	Unrealized profits [Member]	Member			itub:UnrealizedProfitsMember
2128	Disclosure of reserves within equity [line items]	LineItems			ifrs-full:DisclosureOfReservesWithinEquityLineItems
2129	Capital reserves	Concept (Monetary)	As Of	Credit	ifrs-full:CapitalReserve
2130	Revenue reserves	Concept (Monetary)	As Of	Credit	itub:RevenueReserves
2131	Other reserves	Concept (Monetary)	As Of	Credit	ifrs-full:OtherReserves
2132	Total reserves at parent company	Concept (Monetary)	As Of	Credit	itub:AppropriatedReserves
2133	1159 - Disclosure - Stockholders' Equity - Summary of Non-controlling Interests (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureStockholdersEquitySummaryOfNoncontrollingInterests
2134	Disclosure of Non-controlling Interests [Table]	Table	*	*	itub:DisclosureOfNoncontrollingInterestsTable
2135	Subsidiaries [axis]	Axis			ifrs-full:SignificantInvestmentsInSubsidiariesAxis
2136	Entity's total for subsidiaries [member]	Member			ifrs-full:EntitysTotalForSubsidiariesMember
2137	Itau CorpBanca [Member]	Member			itub:ItauCorpbancaMember
2138	Itau Corpbanca Colombia S.A. [Member]	Member			itub:ItauCorpbancaColombiaSAMember
2139	Financeira Itau CBD S.A. Credito, Financiamento e Investimento [Member]	Member			itub:FinanceiraItauCBDSACreditoFinanciamentoeInvestimentoMember
2140	Banco Itau Consignado S.A. [Member]	Member			itub:BancoItauConsignadoSAMember
2141	Luizacred S.A. Sociedade de Credito, Financiamento e Investimento [Member]	Member			itub:LuizacredSASociedadedeCreditoFinanciamentoeInvestimentoMember
2142	Others [Member]	Member			itub:OtherSubsidiariesMember
2143	Disclosure of noncontrolling interests [Line Items]	LineItems			itub:DisclosureOfNoncontrollingInterestsLineItems
2144	Non-controlling interests	Concept (Monetary)	As Of	Credit	ifrs-full:NoncontrollingInterests
2145	Net Income	Concept (Monetary)	For Period	Credit	ifrs-full:ProfitLossAttributableToNoncontrollingInterests
2146	1160 - Disclosure - Share-based payment - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureSharebasedPaymentAdditionalInformation
2147	Disclosure of terms and conditions of share-based payment arrangement [table]	Table	*	*	ifrs-full:DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable
2148	Range [axis]	Axis			ifrs-full:RangeAxis
2149	Ranges [member]	Member			ifrs-full:RangesMember
2150	Top of range [member]	Member			ifrs-full:TopOfRangeMember
2151	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
2152	Types of share-based payment arrangements [axis]	Axis			ifrs-full:TypesOfSharebasedPaymentArrangementsAxis
2153	Share-based payment arrangements [member]	Member			ifrs-full:SharebasedPaymentArrangementsMember
2154	Partner plan [Member]	Member			itub:PartnerPlanMember
2155	Variable compensation [Member]	Member			itub:VariableCompensationMember
2156	Disclosure of terms and conditions of share-based payment arrangement [line items]	LineItems			ifrs-full:DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems
2157	Percentage of shares held by controlling and minority stockholders	Concept (Percent)	For Period		itub:PercentageOfSharesHeld
2158	Accounting effect of share-based payment in income	Concept (Monetary)	As Of	Credit	itub:ShareBasedPaymentArrangementValuationEffectOnNetIncome
2159	Options vesting period	Concept (xbrli:durationItemType)	For Period		itub:OptionVestingPeriod
2160	Weighted average fair value of shares	Concept (Monetary)	For Period		ifrs-full:WeightedAverageSharePrice
2161	Percentage of variable compensation paid in cash	Concept (Percent)	For Period		itub:ProportionOfVariableCompensationPaidInCash
2162	Percentage of variable compensation paid in shares	Concept (Percent)	For Period		itub:ProportionOfVariableCompensationPaidInShares
2163	Period of variable compensation paid in shares	Concept (Text/String)	For Period		itub:PeriodOfVariableCompensationPaidInShares
2164	1161 - Disclosure - Share-based payment - Summary of Changes in Share-based Compensation Plan (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureSharebasedPaymentSummaryOfChangesInSharebasedCompensationPlan
2165	Disclosure Of Share Based Compensation Plans [Table]	Table	*	*	itub:DisclosureOfShareBasedCompensationPlansTable
2166	Ranges of exercise prices for outstanding share options [axis]	Axis			ifrs-full:RangesOfExercisePricesForOutstandingShareOptionsAxis
2167	Ranges of exercise prices for outstanding share options [member]	Member			ifrs-full:RangesOfExercisePricesForOutstandingShareOptionsMember
2168	Range of exercise prices granting two thousand ten to two thousand eleven [Member]	Member			itub:RangeOfExercisePricesGrantingTwoThousandTenToTwoThousandElevenMember
2169	Range of exercise prices granting two thousand twelve [Member]	Member			itub:RangeOfExercisePricesGrantingTwoThousandTwelveMember
2170	Range of exercise prices granting two thousand nine to two thousand ten [Member]	Member			itub:RangeOfExercisePricesGrantingTwoThousandNineToTwoThousandTenMember
2171	Range of exercise prices granting two thousand eleven to two thousand twelve [Member]	Member			itub:RangeOfExercisePricesGrantingTwoThousandElevenToTwoThousandTwelveMember
2172	Types of share-based payment arrangements [axis]	Axis			ifrs-full:TypesOfSharebasedPaymentArrangementsAxis
2173	Share-based payment arrangements [member]	Member			ifrs-full:SharebasedPaymentArrangementsMember
2174	Partner plan [Member]	Member			itub:PartnerPlanMember
2175	Variable compensation [Member]	Member			itub:VariableCompensationMember
2176	Range [axis]	Axis			ifrs-full:RangeAxis
2177	Ranges [member]	Member			ifrs-full:RangesMember
2178	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
2179	Top of range [member]	Member			ifrs-full:TopOfRangeMember
2180	Disclosure Of Share Based Compensation Plans [Line Items]	LineItems			itub:DisclosureOfShareBasedCompensationPlansLineItems
2181	Exercised	Concept (Monetary)	For Period		ifrs-full:WeightedAverageSharePrice
2182	Simple options Weighted average exercise price	Concept (Monetary)	As Of		ifrs-full:WeightedAverageExercisePriceOfShareOptionsOutstandingInSharebasedPaymentArrangement
2183	Options exercisable at the end of the period	Concept (Monetary)	As Of		ifrs-full:WeightedAverageExercisePriceOfShareOptionsExercisableInSharebasedPaymentArrangement
2184	Options outstanding but not exercisable	Concept (Monetary)	As Of		itub:WeightedAverageExercisePriceOfShareOptionsNotExercisableInSharebasedPaymentArrangement
2185	Granted	Concept (Monetary)	For Period		ifrs-full:WeightedAverageExercisePriceOfShareOptionsGrantedInSharebasedPaymentArrangement
2186	Canceled / Forfeited	Concept (Monetary)	For Period		ifrs-full:WeightedAverageExercisePriceOfShareOptionsForfeitedInSharebasedPaymentArrangement
2187	Exercised	Concept (Monetary)	For Period		ifrs-full:WeightedAverageExercisePriceOfShareOptionsExercisedInSharebasedPaymentArrangement
2188	Simple options Weighted average exercise price	Concept (Monetary)	As Of		ifrs-full:WeightedAverageExercisePriceOfShareOptionsOutstandingInSharebasedPaymentArrangement
2189	Options exercisable at the end of the period	Concept (Monetary)	As Of		ifrs-full:WeightedAverageExercisePriceOfShareOptionsExercisableInSharebasedPaymentArrangement
2190	Options outstanding but not exercisable	Concept (Monetary)	As Of		itub:WeightedAverageExercisePriceOfShareOptionsNotExercisableInSharebasedPaymentArrangement
2191	Granting	Concept (Monetary)	For Period		ifrs-full:WeightedAverageExercisePriceOfShareOptionsInSharebasedPaymentArrangementExercisedDuringPeriodAtDateOfExercise
2192	Beginning balance	Concept (Decimal)	As Of		ifrs-full:NumberOfOutstandingShareOptions
2193	Options exercisable at the end of the period	Concept (Decimal)	As Of		ifrs-full:NumberOfShareOptionsExercisableInSharebasedPaymentArrangement
2194	Options outstanding but not exercisable	Concept (Decimal)	As Of		itub:NumberOfShareOptionsNotExercisableInShareBasedPaymentArrangement
2195	Granted	Concept (Decimal)	For Period		ifrs-full:NumberOfShareOptionsGrantedInSharebasedPaymentArrangement
2196	Canceled / Forfeited	Concept (Decimal)	For Period		ifrs-full:NumberOfShareOptionsForfeitedInSharebasedPaymentArrangement
2197	Delivered	Concept (Decimal)	For Period		itub:NumberOfShareOptionsDeliveredInShareBasedPaymentArrangement
2198	Cancelled	Concept (Decimal)	For Period		itub:NumberOfShareOptionsCancelledInShareBasedPaymentArrangement
2199	Exercised	Concept (Decimal)	For Period		ifrs-full:NumberOfShareOptionsExercisedInSharebasedPaymentArrangement
2200	Ending balance	Concept (Decimal)	As Of		ifrs-full:NumberOfOutstandingShareOptions
2201	Options exercisable at the end of the period	Concept (Decimal)	As Of		ifrs-full:NumberOfShareOptionsExercisableInSharebasedPaymentArrangement
2202	Options outstanding but not exercisable	Concept (Decimal)	As Of		itub:NumberOfShareOptionsNotExercisableInShareBasedPaymentArrangement
2203	Weighted average of remaining contractual life (years)	Concept (Decimal)	As Of		ifrs-full:WeightedAverageRemainingContractualLifeOfOutstandingShareOptions
2204	1162 - Disclosure - Interest and similar income and expense and net gain (loss) on investment securities and derivatives - Summary of Interest and Similar Income (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInterestAndSimilarIncomeAndExpenseAndNetGainlossOnInvestmentSecuritiesAndDerivativesSummaryOfInterestAndSimilarIncome
2205	Disclosure of Interest Income [table]	Table	*	*	itub:DisclosureOfInterestIncomeTable
2206	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
2207	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
2208	Central Bank compulsory deposits [Member]	Member			itub:CentralBankCompulsoryDepositsMemberMember
2209	Interbank deposits [Member]	Member			itub:InterbankDepositsMember
2210	Securities purchased under agreements to resell [Member]	Member			itub:SecuritiesPurchasedUnderAgreementsToResellMember
2211	Held-for-trading financial assets [Member]	Member			ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTradingCategoryMember
2212	Available-for-sale financial assets [Member]	Member			ifrs-full:FinancialAssetsAvailableforsaleCategoryMember
2213	Loan and lease operations [Member]	Member			itub:LoanAndLeaseOperationsMember
2214	Other financial asset [Member]	Member			itub:OtherFinancialAssetMember
2215	Categories of financial assets [axis]	Axis			ifrs-full:CategoriesOfFinancialAssetsAxis
2216	Financial assets, category [member]	Member			ifrs-full:FinancialAssetsCategoryMember
2217	Held-to-maturity financial assets [Member]	Member			ifrs-full:HeldtomaturityInvestmentsCategoryMember
2218	Disclosure Of Interest Income [Line Items]	LineItems			itub:DisclosureOfInterestIncomeLineItems
2219	Interest and similar income	Concept (Monetary)	For Period	Credit	itub:InterestAndSimilarIncome
2220	1163 - Disclosure - Interest and similar income and expense and net gain (loss) on investment securities and derivatives - Summary of Interest and Similar Expense (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInterestAndSimilarIncomeAndExpenseAndNetGainlossOnInvestmentSecuritiesAndDerivativesSummaryOfInterestAndSimilarExpense
2221	Disclosure Of Interest Expense [Table]	Table	*	*	itub:DisclosureOfInterestExpenseTable
2222	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
2223	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
2224	Bank Deposits [Member]	Member			itub:BankDepositsMember
2225	Securities sold under repurchase agreements [Member]	Member			itub:SecuritiesSoldUnderRepurchaseAgreementsMember
2226	Inter bank market debt [Member]	Member			itub:InterBankMarketDebtMember
2227	Institutional market debt [Member]	Member			itub:InstitutionalMarketDebtMember
2228	Finance Expense [Member]	Member			itub:FinanceExpenseMember
2229	Other interest and similar expense [Member]	Member			itub:OtherInterestAndSimilarExpenseMember
2230	Disclosure Of Interest Expense [Line items]	LineItems			itub:DisclosureOfInterestExpenseLineItems
2231	Financial expense from technical reserves for insurance and private pension plans	Concept (Monetary)	For Period	Debit	itub:InterestAndSimilarExpense
2232	1164 - Disclosure - Interest and similar income and expense and net gain (loss) on investment securities and derivatives - Summary of Net Gain (Loss) on Investment Securities and Derivatives (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInterestAndSimilarIncomeAndExpenseAndNetGainlossOnInvestmentSecuritiesAndDerivativesSummaryOfNetGainLossOnInvestmentSecuritiesAndDerivatives
2233	Disclosure Gain (loss) on investment securities and derivatives [Table]	Table	*	*	itub:DisclosureGainLossOnInvestmentSecuritiesAndDerivativesTable
2234	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
2235	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
2236	Held-for-trading financial assets [Member]	Member			ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTradingCategoryMember
2237	Derivatives [member]	Member			ifrs-full:DerivativesMember
2238	Financial Assets Designated At Fair Value Through Profit Or Loss Equity Securities [Member]	Member			itub:FinancialAssetsDesignatedAtFairValueThroughProfitOrLossEquitySecuritiesMember
2239	Available-for-sale financial assets [Member]	Member			ifrs-full:FinancialAssetsAvailableforsaleCategoryMember
2240	Financial liabilities held for trading [Member]	Member			itub:FinancialLiabilitiesHeldForTradingMember
2241	Categories of financial assets [axis]	Axis			ifrs-full:CategoriesOfFinancialAssetsAxis
2242	Financial assets, category [member]	Member			ifrs-full:FinancialAssetsCategoryMember
2243	Held-to-maturity financial assets [Member]	Member			ifrs-full:HeldtomaturityInvestmentsCategoryMember
2244	Disclosure Of Other Income Expenses From Investments [Line Items]	LineItems			itub:DisclosureOfOtherIncomeExpensesFromInvestmentsLineItems
2245	Gain loss on investment securities and derivatives	Concept (Monetary)	For Period	Credit	itub:GainLossOnInvestmentSecuritiesAndDerivatives
2246	1165 - Disclosure - Interest and similar income and expense and net gain (loss) on investment securities and derivatives - Summary of Net Gain (Loss) on Investment Securities and Derivatives (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInterestAndSimilarIncomeAndExpenseAndNetGainlossOnInvestmentSecuritiesAndDerivativesSummaryOfNetGainLossOnInvestmentSecuritiesAndDerivativesParenthetical
2247	Disclosure Gain (loss) on investment securities and derivatives [Table]	Table	*	*	itub:DisclosureGainLossOnInvestmentSecuritiesAndDerivativesTable
2248	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
2249	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
2250	Derivatives [member]	Member			ifrs-full:DerivativesMember
2251	Disclosure Of Other Income Expenses From Investments [Line Items]	LineItems			itub:DisclosureOfOtherIncomeExpensesFromInvestmentsLineItems
2252	Impairment expense	Concept (Monetary)	For Period	Debit	ifrs-full:ImpairmentLossOnFinancialAssets
2253	Available-for-sale securities	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAvailableforsale
2254	Held-to-maturity financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:HeldtomaturityInvestments
2255	Total loss, net of reversals	Concept (Monetary)	For Period	Credit	itub:GainLossOnReversalOfDerivatives
2256	1166 - Disclosure - Banking service fees - Schedule of Banking Service Fees (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureBankingServiceFeesScheduleOfBankingServiceFees
2257	Implied Table	Table	*	*	implied:Table
2258	Banking Service Fees [Abstract]	Abstract			itub:BankingServiceFeesAbstract
2259	Current account services	Concept (Monetary)	For Period	Debit	itub:CurrentAccountServices
2260	Asset management fees	Concept (Monetary)	For Period	Credit	itub:AssetManagementFeesIncome
2261	Collection commissions	Concept (Monetary)	For Period	Debit	itub:CollectionCommissions
2262	Fees from credit card services	Concept (Monetary)	For Period	Debit	itub:FeesFromCreditCardServices
2263	Fees for guarantees issued and credit lines	Concept (Monetary)	For Period	Debit	itub:FeesForGuaranteesIssuedAndCreditLines
2264	Brokerage commission	Concept (Monetary)	For Period	Debit	itub:BrokerageCommission
2265	Other	Concept (Monetary)	For Period	Debit	itub:OtherBankingServices
2266	Total	Concept (Monetary)	For Period	Credit	itub:BankingServiceFees
2267	1167 - Disclosure - Other Income - Summary of Other Income (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureOtherIncomeSummaryOfOtherIncome
2268	Implied Table	Table	*	*	implied:Table
2269	Disclosure of other operating income expense [abstract]	Abstract			itub:DisclosureOfOtherOperatingIncomeExpenseAbstract
2270	Gains on sale of assets held for sale, fixed assets and investments in associates and joint ventures	Concept (Monetary)	For Period	Credit	ifrs-full:GainsOnDisposalsOfNoncurrentAssets
2271	Recovery of expenses	Concept (Monetary)	For Period	Credit	itub:RecoveryOfExpenses
2272	Reversal of provisions	Concept (Monetary)	For Period	Credit	itub:RecoveryOfProvisions
2273	Program for Cash or Installment Payment of Federal Taxes	Concept (Monetary)	For Period	Credit	itub:ProgramForCashOrInstallmentPaymentOfFederalTaxes
2274	Other	Concept (Monetary)	For Period	Credit	ifrs-full:MiscellaneousOtherOperatingIncome
2275	Total	Concept (Monetary)	For Period	Credit	ifrs-full:OtherIncome
2276	1168 - Disclosure - General and Administrative Expenses - Summary of General and Administrative Expenses (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureGeneralAndAdministrativeExpensesSummaryOfGeneralAndAdministrativeExpenses
2277	Disclosure Of Details About General And Administrative Expense [Table]	Table	*	*	itub:DisclosureOfDetailsAboutGeneralAndAdministrativeExpenseTable
2278	Continuing and discontinued operations [axis]	Axis			ifrs-full:ContinuingAndDiscontinuedOperationsAxis
2279	Aggregate continuing and discontinued operations [member]	Member			ifrs-full:AggregateContinuingAndDiscontinuedOperationsMember
2280	General and Administrative Expense [Member]	Member			us-gaap:GeneralAndAdministrativeExpenseMember
2281	Disclosure Of Details About General And Administrative Expense [Line Items]	LineItems			itub:DisclosureOfDetailsAboutGeneralAndAdministrativeExpenseLineItems
2282	Personnel expenses	Concept (Monetary)	For Period	Debit	ifrs-full:EmployeeBenefitsExpense
2283	Compensation	Concept (Monetary)	For Period	Debit	ifrs-full:KeyManagementPersonnelCompensation
2284	Payroll taxes	Concept (Monetary)	For Period	Debit	itub:PayrollTaxes
2285	Welfare benefits	Concept (Monetary)	For Period	Debit	ifrs-full:BenefitsPaidOrPayable
2286	Retirement plans and post-employment benefits (Note 29)	Concept (Monetary)	For Period	Debit	ifrs-full:KeyManagementPersonnelCompensationPostemploymentBenefits
2287	Defined benefit	Concept (Monetary)	For Period	Debit	ifrs-full:PostemploymentBenefitExpenseDefinedBenefitPlans
2288	Defined contribution	Concept (Monetary)	For Period	Debit	ifrs-full:PostemploymentBenefitExpenseDefinedContributionPlans
2289	Stock option plan (Note 22d)	Concept (Monetary)	For Period	Debit	ifrs-full:ExpenseFromSharebasedPaymentTransactionsWithEmployees
2290	Training	Concept (Monetary)	For Period	Debit	itub:TrainingExpense
2291	Employee profit sharing	Concept (Monetary)	For Period	Debit	itub:EmployeeProfitSharing
2292	Dismissals	Concept (Monetary)	For Period	Debit	ifrs-full:TerminationBenefitsExpense
2293	Provision for labor claims (Note 32)	Concept (Monetary)	For Period	Debit	itub:ProvisionForLaborClaims
2294	Administrative expenses	Concept (Monetary)	For Period	Debit	ifrs-full:AdministrativeExpense
2295	Data processing and telecommunications	Concept (Monetary)	For Period	Debit	ifrs-full:CommunicationExpense
2296	Third party services	Concept (Monetary)	For Period	Debit	ifrs-full:ServicesReceivedRelatedPartyTransactions
2297	Installations	Concept (Monetary)	For Period	Debit	itub:InstallationFee
2298	Advertising, promotions and publications	Concept (Monetary)	For Period	Debit	ifrs-full:SalesAndMarketingExpense
2299	Rent	Concept (Monetary)	For Period	Debit	ifrs-full:RentalExpense
2300	Transportation	Concept (Monetary)	For Period	Debit	ifrs-full:TransportationExpense
2301	Materials	Concept (Monetary)	For Period	Debit	ifrs-full:RawMaterialsAndConsumablesUsed
2302	Financial services	Concept (Monetary)	For Period	Debit	ifrs-full:ProfessionalFeesExpense
2303	Security	Concept (Monetary)	For Period	Debit	itub:SecurityServices
2304	Utilities	Concept (Monetary)	For Period	Debit	ifrs-full:UtilitiesExpense
2305	Travel	Concept (Monetary)	For Period	Debit	ifrs-full:TravelExpense
2306	Other	Concept (Monetary)	For Period	Debit	itub:OtherAdministrativeExpenses
2307	Depreciation	Concept (Monetary)	For Period	Debit	ifrs-full:DepreciationExpense
2308	Amortization	Concept (Monetary)	For Period	Debit	ifrs-full:AmortisationExpense
2309	Insurance acquisition expenses	Concept (Monetary)	For Period	Debit	ifrs-full:InsuranceExpense
2310	Other expenses	Concept (Monetary)	For Period	Debit	ifrs-full:OtherExpenseByFunction
2311	Expenses related to credit cards	Concept (Monetary)	For Period	Debit	itub:CreditCardsCost
2312	Losses with third party frauds	Concept (Monetary)	For Period	Debit	itub:LossesWithThirdPartyFrauds
2313	Loss on sale of assets held for sale, fixed assets and investments in associates and joint ventures	Concept (Monetary)	For Period	Debit	itub:LossOnSaleOfAssetsHeldForSaleFixedAssetsAndInvestmentsInAssociatesAndJointVentures
2314	Provision for civil lawsuits (Note 32)	Concept (Monetary)	For Period	Debit	itub:ProvisionForCivilLawsuits
2315	Provision for tax and social security lawsuits	Concept (Monetary)	For Period	Debit	itub:ProvisionForTaxAndSocialSecurityLawsuits
2316	Refund of interbank costs	Concept (Monetary)	For Period	Debit	itub:RefundOfInterbankCosts
2317	Provision for Citibank integration expenditures	Concept (Monetary)	For Period	Debit	itub:ProvisionForAcquisitionIntegrationExpenses
2318	Other	Concept (Monetary)	For Period	Debit	ifrs-full:MiscellaneousOtherOperatingExpense
2319	Total	Concept (Monetary)	For Period	Debit	ifrs-full:SellingGeneralAndAdministrativeExpense
2320	1169 - Disclosure - Income Tax and Social Contribution - Demonstration of Income Tax and Social Contribution Expense (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureIncomeTaxAndSocialContributionDemonstrationOfIncomeTaxAndSocialContributionExpense
2321	Implied Table	Table	*	*	implied:Table
2322	Major components of tax expense (income) [abstract]	Abstract			ifrs-full:MajorComponentsOfTaxExpenseIncomeAbstract
2323	Income before income tax and social contribution	Concept (Monetary)	For Period	Credit	itub:ProfitLossBeforeTaxAndSocialContribution
2324	Charges (income tax and social contribution) at the rates in effect (Note 2.4 k)	Concept (Monetary)	For Period	Debit	itub:ChargesInIncomeTaxAndSocialContributionAtRatesInEffect
2325	Increase / decrease in income tax and social contribution charges arising from:	Abstract			itub:IncreaseDecreaseInIncomeTaxAndSocialContributionChargesAbstract
2326	Share of profit or (loss) of associates and joint ventures net	Concept (Monetary)	For Period	Credit	itub:ShareOfProfitLossFromContinuingOperationsOfAssociatesAndJointVenturesAccountedForUsingEquityMethod
2327	Foreign exchange variation on investments abroad	Concept (Monetary)	For Period	Credit	ifrs-full:GainsLossesOnExchangeDifferencesOnTranslationRecognisedInProfitOrLoss
2328	Interest on capital	Concept (Monetary)	For Period	Debit	itub:InterestOnCapital
2329	Corporate reorganizations (Note 2.4 a III)	Concept (Monetary)	For Period	Credit	itub:CorporateReorganizations
2330	Dividends and interest on external debt bonds	Concept (Monetary)	For Period	Credit	itub:DividendsAndInterestOnExternalDebtBonds
2331	Other nondeductible expenses net of non taxable income	Concept (Monetary)	For Period	Credit	itub:OtherNondeductibleExpensesNetOfNonTaxableIncome
2332	Income tax and social contribution expenses	Concept (Monetary)	For Period	Debit	itub:CurrentIncomeTaxAndSocialContributionExpenseBenefit
2333	Related to temporary differences	Abstract			itub:RelatedToTemporaryDifferencesAbstract
2334	Increase (reversal) for the period	Concept (Monetary)	For Period	Debit	ifrs-full:AdjustmentsForCurrentTaxOfPriorPeriod
2335	Increase (reversal) of prior periods	Concept (Monetary)	For Period	Debit	ifrs-full:CurrentTaxExpenseIncomeAndAdjustmentsForCurrentTaxOfPriorPeriods
2336	Increase in the social contribution tax rate (Note 27b III)	Concept (Monetary)	For Period	Debit	itub:IncreaseDecreaseInSocialContributionTaxRate
2337	(Expenses)/Income related to deferred taxes	Concept (Monetary)	For Period	Debit	itub:DeferredIncomeTaxAndSocialContributionExpenseBenefit
2338	Total income tax and social contribution expenses	Concept (Monetary)	For Period	Debit	itub:IncomeTaxAndSocialContributionExpenses
2339	1170 - Disclosure - Income Tax and Social Contribution - Summary of Deferred Tax Asset Balance and Respective Changes (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureIncomeTaxAndSocialContributionSummaryOfDeferredTaxAssetBalanceAndRespectiveChanges
2340	Deferred Tax Assets [Table]	Table	*	*	itub:DeferredTaxAssetsTable
2341	Temporary difference, unused tax losses and unused tax credits [axis]	Axis			ifrs-full:TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis
2342	Temporary difference, unused tax losses and unused tax credits [member]	Member			ifrs-full:TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsMember
2343	Reflected in income [Member]	Member			itub:ReflectedInIncomeMember
2344	Allowance for Loan and Lease Losses [Member]	Member			us-gaap:AllowanceForLoanAndLeaseLossesMember
2345	Related to income tax and social contribution tax carryforwards [Member]	Member			itub:RelatedToIncomeTaxAndSocialContributionTaxCarryforwardsMember
2346	Provision for contingent liabilities [Member]	Member			itub:ProvisionForContingentLiabilitiesMember
2347	Civil lawsuits [Member]	Member			itub:CivilLawsuitsMember
2348	Labor claims [Member]	Member			itub:LaborClaimsMember
2349	Tax and social security [Member]	Member			itub:TaxAndSocialSecurityMember
2350	Other [Member]	Member			itub:OtherMember
2351	Goodwill on purchase of investments [Member]	Member			itub:GoodwillOnPurchaseOfInvestmentsMember
2352	Legal liabilities - tax and social security [Member]	Member			itub:LegalLiabilitiesTaxAndSocialSecurityMember
2353	Adjustments of operations carried out on futures settlement market [Member]	Member			itub:AdjustmentsOfOperationsCarriedOutOnFuturesSettlementMarketMember
2354	Adjustment to market value of financial assets held for trading and derivatives [Member]	Member			itub:AdjustmentToMarketValueOfFinancialAssetsHeldForTradingAndDerivativesMember
2355	Provision related to health insurance operations [Member]	Member			itub:ProvisionRelatedToHealthInsuranceOperationsMember
2356	Other Items Reflected In Income [Member]	Member			itub:OtherItemsReflectedInIncomeMember
2357	Reflected In Stockholder Equity [Member]	Member			itub:ReflectedInStockholderEquityMember
2358	Corporate reorganizations [Member]	Member			itub:CorporateReorganizationsMember
2359	Adjustment to market value of available-for-sale securities [Member]	Member			itub:AdjustmentToMarketValueOfAvailableforsaleSecuritiesMember
2360	Other [Member]	Member			itub:OtherItemsReflectedInIncomeStockholderEquityMember
2361	Depreciation in excess - finance lease[Member]	Member			itub:DepreciationInExcessFinanceLeaseMember
2362	Adjustment of escrow deposits and contingent liabilities [Member]	Member			itub:AdjustmentOfEscrowDepositsAndContingentLiabilitiesMember
2363	Pension Plans [member]	Member			itub:PensionPlansMember
2364	Taxation of results abroad - capital gains [Member]	Member			itub:TaxationOfResultsAbroadCapitalGainsMember
2365	Provision for pension plan benefits [Member]	Member			itub:ProvisionForPensionPlanBenefitsMember
2366	Types of hedges [axis]	Axis			ifrs-full:TypesOfHedgesAxis
2367	Hedges [member]	Member			ifrs-full:TypesOfHedgesMember
2368	Cash flow hedges [member]	Member			ifrs-full:CashFlowHedgesMember
2369	Deferred Tax Assets [Line Items]	LineItems			itub:DeferredTaxAssetsLineItems
2370	Beginning balance	Concept (Monetary)	As Of	Debit	ifrs-full:DeferredTaxAssets
2371	Realization / reversal	Concept (Monetary)	For Period	Debit	itub:RealizationReversalInDeferredTaxAssets
2372	Increase	Concept (Monetary)	For Period	Debit	itub:IncreaseDecreaseInDeferredTaxAssets
2373	Ending balance	Concept (Monetary)	As Of	Debit	ifrs-full:DeferredTaxAssets
2374	Beginning balance	Concept (Monetary)	As Of	Credit	itub:ProvisionForDeferredTaxAndContributions
2375	Realization / reversal	Concept (Monetary)	For Period	Debit	itub:RealizationReversalProvisionForDeferredTaxAndContributions
2376	Increase	Concept (Monetary)	For Period	Credit	itub:IncreaseInProvisionForDeferredTaxAndContributions
2377	Ending balance	Concept (Monetary)	As Of	Credit	itub:ProvisionForDeferredTaxAndContributions
2378	1171 - Disclosure - Income Tax and Social Contribution - Summary of Deferred Tax Asset Balance and Respective Changes (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureIncomeTaxAndSocialContributionSummaryOfDeferredTaxAssetBalanceAndRespectiveChangesParenthetical
2379	Implied Table	Table	*	*	implied:Table
2380	Deferred tax assets [abstract]	Abstract			itub:DeferredTaxAssetsAbstract
2381	Deferred income tax and social contribution assets	Concept (Monetary)	As Of	Debit	itub:IncomeTaxAndSocialContributionDeferredAssets
2382	Deferred income tax and social contribution liabilities	Concept (Monetary)	As Of	Credit	itub:IncomeTaxAndSocialContributionDeferredLiabilities
2383	Deferred income tax and social contribution assets	Concept (Monetary)	As Of	Debit	itub:IncomeTaxAndSocialContributionDeferredAssets
2384	Deferred income tax and social contribution liabilities	Concept (Monetary)	As Of	Credit	itub:IncomeTaxAndSocialContributionDeferredLiabilities
2385	1172 - Disclosure - Income Tax and Social Contribution - Summary of Realization and Present Value of Tax Credits and From Provision for Deferred Income Tax and Social Contribution (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureIncomeTaxAndSocialContributionSummaryOfRealizationAndPresentValueOfTaxCreditsAndFromProvisionForDeferredIncomeTaxAndSocialContribution
2386	Disclosure of estimate of realization and present value of net deferred taxes [table]	Table	*	*	itub:DisclosureOfEstimateOfRealizationAndPresentValueOfNetDeferredTaxesTable
2387	Maturity [axis]	Axis			ifrs-full:MaturityAxis
2388	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
2389	Current [Member]	Member			ifrs-full:NotLaterThanOneYearMember
2390	Later than one year and not later than two years [member]	Member			ifrs-full:LaterThanOneYearAndNotLaterThanTwoYearsMember
2391	Later than one year and not later than three years [member]	Member			ifrs-full:LaterThanOneYearAndNotLaterThanThreeYearsMember
2392	Later than three years and not later than four years [member]	Member			ifrs-full:LaterThanThreeYearsAndNotLaterThanFourYearsMember
2393	Later than four years and not later than five years [member]	Member			ifrs-full:LaterThanFourYearsAndNotLaterThanFiveYearsMember
2394	Over 5 years [Member]	Member			ifrs-full:LaterThanFiveYearsMember
2395	Disclosure of estimate of realization and present value of net deferred taxes [line items]	LineItems			itub:DisclosureOfEstimateOfRealizationAndPresentValueOfNetDeferredTaxesLineItems
2396	Temporary differences	Concept (Monetary)	As Of	Debit	itub:DeferredTaxAssetsTemporaryDifferences
2397	Temporary differences, percentage	Concept (Percent)	As Of		itub:DeferredTaxAssetsTemporaryDifferencesPercentage
2398	Deferred tax assets Tax loss /social contribution loss Carryforwards	Concept (Monetary)	As Of	Debit	itub:DeferredTaxAssetsTaxLossCarryForwards
2399	Deferred tax assets Tax loss /social contribution loss Carryforwards, percentage	Concept (Percent)	As Of		itub:DeferredTaxAssetsTaxLossCarryForwardsPercentage
2400	Deferred tax assets	Concept (Monetary)	As Of	Debit	ifrs-full:DeferredTaxAssets
2401	Deferred tax assets, percentage	Concept (Percent)	As Of		itub:DeferredTaxAssetsPercentage
2402	Deferred tax liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:DeferredTaxLiabilities
2403	Deferred tax liabilities, percentage	Concept (Percent)	As Of		itub:DeferredTaxLiabilitiesPercentage
2404	Net deferred taxes	Concept (Monetary)	As Of	Debit	ifrs-full:NetDeferredTaxAssets
2405	Net deferred taxes,percentage	Concept (Percent)	As Of		itub:NetDeferredTaxAssetsPercentage
2406	Present value of temporary differences	Concept (Monetary)	As Of	Debit	itub:PresentValueOfDeferredTaxAssetsTemporaryDifferences
2407	Present value of tax loss /social contribution loss carryforwards	Concept (Monetary)	As Of	Debit	itub:PresentValueOfDeferredTaxAssetsTaxLossCarryForwards
2408	Present value of deferred tax assets	Concept (Monetary)	As Of	Debit	itub:PresentValueOfDeferredTaxAssets
2409	Present value of deferred tax liabilities	Concept (Monetary)	As Of	Credit	itub:PresentValueOfDeferredTaxLiabilities
2410	Present value of net deferred taxes	Concept (Monetary)	As Of	Debit	itub:PresentValueOfNetDeferredTaxAssets
2411	1173 - Disclosure - Income Tax and Social Contribution - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureIncomeTaxAndSocialContributionAdditionalInformation
2412	Implied Table	Table	*	*	implied:Table
2413	Disclosure of estimate of realization and present value of net deferred taxes [abstract]	Abstract			itub:DisclosureOfEstimateOfRealizationAndPresentValueOfNetDeferredTaxesAbstract
2414	Social contribution tax rate	Concept (Percent)	For Period		itub:SocialContributionTaxRate
2415	Unrecorded deferred tax assets	Concept (Monetary)	As Of	Debit	itub:UnrecognizedDeferredTaxAssets
2416	1174 - Disclosure - Earnings Per Share - Summary of Earnings Per Share (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureEarningsPerShareSummaryOfEarningsPerShare
2417	Earnings per share [table]	Table	*	*	ifrs-full:EarningsPerShareTable
2418	Classes of share capital [axis]	Axis			ifrs-full:ClassesOfShareCapitalAxis
2419	Share capital [member]	Member			ifrs-full:ClassesOfShareCapitalMember
2420	Ordinary shares [member]	Member			ifrs-full:OrdinarySharesMember
2421	Preference shares [member]	Member			ifrs-full:PreferenceSharesMember
2422	Earnings per share [line items]	LineItems			ifrs-full:EarningsPerShareLineItems
2423	Net income	Concept (Monetary)	For Period	Credit	ifrs-full:ProfitLossAttributableToOwnersOfParent
2424	Minimum non-cumulativedividend on preferred shares in accordance with our by laws	Concept (Monetary)	For Period	Debit	itub:MinimumNonCumulativeDividendOnPreferredShares
2425	Weighted average number of shares outstanding	Concept (Shares)	For Period		ifrs-full:WeightedAverageShares
2426	Subtotal	Concept (Monetary)	For Period	Credit	itub:ProfitLossAttributableToOwnersOfParentAfterNonCumulativeDividendOnPreferredShares
2427	Total net income available to ordinary equity owners	Concept (Monetary)	For Period	Credit	ifrs-full:ProfitLossAttributableToOwnersOfParent
2428	Retained earnings to be distributed to common equity owners in an amount per share equal to the minimum dividend payable to preferred equity owners	Concept (Monetary)	For Period	Debit	itub:RetainedEarningsToBeDistributedToCommonShares
2429	Dividend on preferred shares after dilution effects	Concept (Monetary)	For Period	Debit	itub:DividendOnPreferredSharesAfterDilutionEffects
2430	Subtotal	Concept (Monetary)	For Period	Credit	itub:ProfitLossAttributableToOwnersOfParentAfterDistributionToPreferredAndCommonShares
2431	Net income available to ordinary equity owners considering preferred shares after the dilution effect	Concept (Monetary)	For Period	Credit	ifrs-full:ProfitLossAttributableToOrdinaryEquityHoldersOfParentEntityIncludingDilutiveEffects
2432	Retained earnings to be distributed to common and preferred equity owners on a pro-rata basis	Abstract			itub:RetainedEarningsAbstract
2433	Retained earnings	Concept (Monetary)	For Period	Debit	itub:RetainedEarningsToBeDistributedToOwnersOfParentOnProRataBasis
2434	Common shares	Concept (Shares)	For Period		ifrs-full:AdjustedWeightedAverageShares
2435	Earnings per share - basic vv	Abstract			ifrs-full:BasicEarningsPerShareAbstract
2436	Basic earnings per share	Concept (Share)	For Period		ifrs-full:BasicEarningsLossPerShare
2437	Preferred shares	Concept (Shares)	For Period		ifrs-full:WeightedAverageShares
2438	Common shares	Concept (Share)	For Period		ifrs-full:DilutedEarningsLossPerShare
2439	Incremental shares from stock options granted under our share-based payment	Concept (Shares)	For Period		ifrs-full:DilutiveEffectOfShareOptionsOnNumberOfOrdinaryShares
2440	1175 - Disclosure - Earnings Per Share - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureEarningsPerShareAdditionalInformation
2441	Implied Table	Table	*	*	implied:Table
2442	Earnings per share [abstract]	Abstract			ifrs-full:EarningsPerShareAbstract
2443	Potential anti-dilutive preferred shares excluded from calculation of diluted earnings	Concept (Shares)	For Period		itub:PotentialAntidilutivePreferredSharesExcludedFromCalculationOfDilutedEarnings
2444	1176 - Disclosure - Post-employment Benefits - Summary of Amounts Recognized in Income for Period (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosurePostemploymentBenefitsSummaryOfAmountsRecognizedInIncomeForPeriod
2445	Disclosure of defined benefit plans [table]	Table	*	*	ifrs-full:DisclosureOfDefinedBenefitPlansTable
2446	Defined benefit plans [axis]	Axis			ifrs-full:DefinedBenefitPlansAxis
2447	Defined benefit plans [member]	Member			ifrs-full:DefinedBenefitPlansMember
2448	Defined Benefit [member]	Member			itub:DefinedBenefitMember
2449	Defined Contribution [Member]	Member			itub:DefinedContributionMember
2450	Other Benefits [Member]	Member			itub:OtherBenefitsMember
2451	Disclosure of defined benefit plans [line items]	LineItems			ifrs-full:DisclosureOfDefinedBenefitPlansLineItems
2452	Cost of current service	Concept (Monetary)	For Period	Credit	ifrs-full:CurrentServiceCostNetDefinedBenefitLiabilityAsset
2453	Net interest	Concept (Monetary)	For Period	Credit	ifrs-full:InterestExpenseIncomeNetDefinedBenefitLiabilityAsset
2454	Contribution	Concept (Monetary)	For Period	Debit	ifrs-full:ContributionsToPlanNetDefinedBenefitLiabilityAsset
2455	Benefits paid	Concept (Monetary)	For Period	Debit	ifrs-full:BenefitsPaidOrPayable
2456	Total Amounts Recognized	Concept (Monetary)	For Period	Debit	ifrs-full:PostemploymentBenefitExpenseDefinedBenefitPlans
2457	1177 - Disclosure - Post-employment Benefits - Summary of Amounts Recognized in Income for Period (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosurePostemploymentBenefitsSummaryOfAmountsRecognizedInIncomeForPeriodParenthetical
2458	Disclosure of defined benefit plans [table]	Table	*	*	ifrs-full:DisclosureOfDefinedBenefitPlansTable
2459	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
2460	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
2461	Social security funds [Member]	Member			itub:SocialSecurityFundsMember
2462	Disclosure of defined benefit plans [line items]	LineItems			ifrs-full:DisclosureOfDefinedBenefitPlansLineItems
2463	Contributions to defined contributions plan, including PGBL	Concept (Monetary)	For Period	Debit	itub:IncreaseDecreaseThroughContributionsByEmployerPlanAssetsAtFairValue
2464	1178 - Disclosure - Post-employment Benefits - Summary of Amounts Recognized in Stockholders' Equity - Other Comprehensive Income (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosurePostemploymentBenefitsSummaryOfAmountsRecognizedInStockholdersEquityOtherComprehensiveIncome
2465	Disclosure of defined benefit plans [table]	Table	*	*	ifrs-full:DisclosureOfDefinedBenefitPlansTable
2466	Reserves within equity [axis]	Axis			ifrs-full:ReservesWithinEquityAxis
2467	Other reserves [member]	Member			ifrs-full:OtherReservesMember
2468	Remeasurements of liabilities of post-employment benefits [member]	Member			ifrs-full:ReserveOfRemeasurementsOfDefinedBenefitPlansMember
2469	Defined benefit plans [axis]	Axis			ifrs-full:DefinedBenefitPlansAxis
2470	Defined benefit plans [member]	Member			ifrs-full:DefinedBenefitPlansMember
2471	Defined Benefit [member]	Member			itub:DefinedBenefitMember
2472	Defined Contribution [Member]	Member			itub:DefinedContributionMember
2473	Other Benefits [Member]	Member			itub:OtherBenefitsMember
2474	Disclosure of defined benefit plans [line items]	LineItems			ifrs-full:DisclosureOfDefinedBenefitPlansLineItems
2475	At the beginning of the period	Concept (Monetary)	As Of	Credit	itub:AmountsRecognizedInStockholdersEquityOtherComprehensiveIncome
2476	Effects on asset ceiling	Concept (Monetary)	For Period	Debit	ifrs-full:GainLossOnChangesInEffectOfLimitingReimbursementRightsToAssetCeiling
2477	Remeasurements	Concept (Monetary)	For Period	Credit	ifrs-full:OtherComprehensiveIncomeNetOfTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans
2478	Acquisition Citibank portfolio	Concept (Monetary)	For Period	Credit	ifrs-full:IncreaseDecreaseThroughBusinessCombinationsAndDisposalsNetDefinedBenefitLiabilityAsset
2479	Total Amounts Recognized	Concept (Monetary)	As Of	Credit	itub:AmountsRecognizedInStockholdersEquityOtherComprehensiveIncome
2480	1179 - Disclosure - Post-employment Benefits - Summary of Main Assumptions Used in Actuarial Valuation of Retirement Plans (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosurePostemploymentBenefitsSummaryOfMainAssumptionsUsedInActuarialValuationOfRetirementPlans
2481	Disclosure of defined benefit plans [table]	Table	*	*	ifrs-full:DisclosureOfDefinedBenefitPlansTable
2482	Range [axis]	Axis			ifrs-full:RangeAxis
2483	Ranges [member]	Member			ifrs-full:RangesMember
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2485	Top of range [member]	Member			ifrs-full:TopOfRangeMember
2486	Disclosure of defined benefit plans [line items]	LineItems			ifrs-full:DisclosureOfDefinedBenefitPlansLineItems
2487	Discount rate	Concept (Percent)	As Of		ifrs-full:ActuarialAssumptionOfDiscountRates
2488	Mortality table	Concept (Text/String)	For Period		itub:DescriptionOfMortality
2489	Turnover	Concept (Text/String)	For Period		itub:Turnover
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2491	Growth of the pension fund and social security benefits	Concept (Percent)	As Of		ifrs-full:ActuarialAssumptionOfExpectedRatesOfPensionIncreases
2492	Inflation	Concept (Percent)	As Of		ifrs-full:ActuarialAssumptionOfExpectedRatesOfInflation
2493	Actuarial method	Concept (Text/String)	For Period		ifrs-full:DescriptionOfMethodsAndAssumptionsUsedInPreparingSensitivityAnalysisForActuarialAssumptions
2494	1180 - Disclosure - Post-employment Benefits - Summary of Main Assumptions Used in Actuarial Valuation of Retirement Plans (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosurePostemploymentBenefitsSummaryOfMainAssumptionsUsedInActuarialValuationOfRetirementPlansParenthetical
2495	Disclosure of defined benefit plans [table]	Table	*	*	ifrs-full:DisclosureOfDefinedBenefitPlansTable
2496	Categories of related parties [axis]	Axis			ifrs-full:CategoriesOfRelatedPartiesAxis
2497	Entity's total for related parties [member]	Member			ifrs-full:EntitysTotalForRelatedPartiesMember
2498	ITAU UNIBANCO HOLDING [Member]	Member			itub:ItauUnibancoHoldingMember
2499	Counterparties [axis]	Axis			ifrs-full:CounterpartiesAxis
2500	Counterparties [member]	Member			ifrs-full:CounterpartiesMember
2501	Men [Member]	Member			itub:MenMember
2502	Women [Member]	Member			itub:WomenMember
2503	Disclosure of defined benefit plans [line items]	LineItems			ifrs-full:DisclosureOfDefinedBenefitPlansLineItems
2504	Increase in probabilities of survival	Concept (Percent)	For Period		itub:PercentageOfIncreaseInProbabilitiesOfSurvival
2505	Life expectancy in years	Concept (Decimal)	For Period		itub:LifeExpectancyInYearsForParticipantsAgedFiftyFiveYears
2506	Turnover	Concept (Text/String)	For Period		itub:Turnover
2507	1181 - Disclosure - Post-employment Benefits - Summary of Allocation of Plan Assets and Allocation Target by Type of Asset (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosurePostemploymentBenefitsSummaryOfAllocationOfPlanAssetsAndAllocationTargetByTypeOfAsset
2508	Disclosure of defined benefit plans [table]	Table	*	*	ifrs-full:DisclosureOfDefinedBenefitPlansTable
2509	Non-adjusting events after reporting period [axis]	Axis			ifrs-full:NonadjustingEventsAfterReportingPeriodAxis
2510	Non-adjusting events after reporting period [member]	Member			ifrs-full:NonadjustingEventsMember
2511	Subsequent Event 1 [member]	Member			itub:SubsequentEvent1Member
2512	Defined benefit plans [axis]	Axis			ifrs-full:DefinedBenefitPlansAxis
2513	Defined benefit plans [member]	Member			ifrs-full:DefinedBenefitPlansMember
2514	Fixed income securities [Member]	Member			itub:FixedIncomeSecurities1Member
2515	Variable income securities [Member]	Member			itub:VariableIncomeSecuritiesMember
2516	Structured investments [Member]	Member			itub:StructuredInvestmentsMember
2517	Real estate [Member]	Member			itub:RealEstate1Member
2518	Loans to participants [Member]	Member			itub:LoansToParticipantsMember
2519	Range [axis]	Axis			ifrs-full:RangeAxis
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2521	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
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2523	Disclosure of defined benefit plans [line items]	LineItems			ifrs-full:DisclosureOfDefinedBenefitPlansLineItems
2524	Fair Value	Concept (Monetary)	As Of	Debit	ifrs-full:PlanAssetsAtFairValue
2525	Percentage of allocation	Concept (Percent)	For Period		itub:PercentageOfAllocationOfPlanAssets
2526	1182 - Disclosure - Post-Employment Benefits - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosurePostEmploymentBenefitsAdditionalInformation
2527	Disclosure of defined benefit plans [table]	Table	*	*	ifrs-full:DisclosureOfDefinedBenefitPlansTable
2528	Categories of related parties [axis]	Axis			ifrs-full:CategoriesOfRelatedPartiesAxis
2529	Entity's total for related parties [member]	Member			ifrs-full:EntitysTotalForRelatedPartiesMember
2530	ITAU UNIBANCO HOLDING [Member]	Member			itub:ItauUnibancoHoldingMember
2531	Actuarial assumptions [axis]	Axis			ifrs-full:ActuarialAssumptionsAxis
2532	Actuarial assumptions [member]	Member			ifrs-full:ActuarialAssumptionsMember
2533	Medical care cost [Member]	Member			ifrs-full:ActuarialAssumptionOfMedicalCostTrendRatesMember
2534	Defined benefit plans [axis]	Axis			ifrs-full:DefinedBenefitPlansAxis
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2536	Real Estate [Member]	Member			itub:RealEstate2Member
2537	Disclosure of defined benefit plans [line items]	LineItems			ifrs-full:DisclosureOfDefinedBenefitPlansLineItems
2538	Defined benefit plan assets	Concept (Monetary)	As Of	Debit	ifrs-full:PlanAssetsAtFairValue
2539	Contributions made	Concept (Monetary)	For Period	Debit	itub:ContributionsPaidNetDefinedBenefitLiabilityAsset
2540	Contribution to the retirement plans	Concept (Monetary)	For Period	Debit	ifrs-full:ContributionsToPlanByEmployerNetDefinedBenefitLiabilityAsset
2541	Percentage of increase in defined benefit plans cost assumption	Concept (Percent)	As Of		ifrs-full:PercentageOfReasonablyPossibleIncreaseInActuarialAssumption
2542	1183 - Disclosure - Post-Employment Benefits - Summary of Calculation of Net Amount Recognized in Balance Sheet, Corresponding to Defined Benefit Plan (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosurePostEmploymentBenefitsSummaryOfCalculationOfNetAmountRecognizedInBalanceSheetCorrespondingToDefinedBenefitPlan
2543	Disclosure of defined benefit plans [table]	Table	*	*	ifrs-full:DisclosureOfDefinedBenefitPlansTable
2544	Net defined benefit liability (asset) [axis]	Axis			ifrs-full:NetDefinedBenefitLiabilityAssetAxis
2545	Net defined benefit liability (asset) [member]	Member			ifrs-full:NetDefinedBenefitLiabilityAssetMember
2546	Present value of defined benefit obligation [member]	Member			ifrs-full:PresentValueOfDefinedBenefitObligationMember
2547	Effect of asset ceiling [member]	Member			ifrs-full:EffectOfAssetCeilingMember
2548	Disclosure of defined benefit plans [line items]	LineItems			ifrs-full:DisclosureOfDefinedBenefitPlansLineItems
2549	1- Net assets of the plans	Concept (Monetary)	As Of	Debit	ifrs-full:PlanAssetsAtFairValue
2550	2- Actuarial liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:DefinedBenefitObligationAtPresentValue
2551	3- Surplus (1-2)	Concept (Monetary)	As Of	Debit	ifrs-full:SurplusDeficitInPlan
2552	5- Net amount recognized in the balance sheet (3-4)	Concept (Monetary)	As Of	Credit	ifrs-full:AssetsLiabilitiesOfBenefitPlan
2553	Amount recognized in assets (Note 20a)	Concept (Monetary)	As Of	Debit	ifrs-full:AssetsOfBenefitPlan
2554	Amount recognized in liabilities (Note 20b)	Concept (Monetary)	As Of	Credit	ifrs-full:RecognisedLiabilitiesDefinedBenefitPlan
2555	1184 - Disclosure - Post-Employment Benefits - Summary of Changes in Net Amount Recognized in Balance Sheet (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosurePostEmploymentBenefitsSummaryOfChangesInNetAmountRecognizedInBalanceSheet
2556	Disclosure of defined benefit plans [table]	Table	*	*	ifrs-full:DisclosureOfDefinedBenefitPlansTable
2557	Net defined benefit liability (asset) [axis]	Axis			ifrs-full:NetDefinedBenefitLiabilityAssetAxis
2558	Net defined benefit liability (asset) [member]	Member			ifrs-full:NetDefinedBenefitLiabilityAssetMember
2559	Plan assets [member]	Member			ifrs-full:PlanAssetsMember
2560	Present value of defined benefit obligation [member]	Member			ifrs-full:PresentValueOfDefinedBenefitObligationMember
2561	Surplus [member]	Member			itub:SurplusMember
2562	Effect of asset ceiling [member]	Member			ifrs-full:EffectOfAssetCeilingMember
2563	Recognized Amount [member]	Member			itub:RecognizedAmountMember
2564	Disclosure of defined benefit plans [line items]	LineItems			ifrs-full:DisclosureOfDefinedBenefitPlansLineItems
2565	At the beginning of the period	Concept (Monetary)	As Of	Credit	ifrs-full:LiabilityAssetOfDefinedBenefitPlans
2566	Cost of current service	Concept (Monetary)	For Period	Credit	ifrs-full:CurrentServiceCostNetDefinedBenefitLiabilityAsset
2567	Net interest	Concept (Monetary)	For Period	Credit	ifrs-full:InterestExpenseIncomeNetDefinedBenefitLiabilityAsset
2568	Benefits paid	Concept (Monetary)	For Period	Debit	ifrs-full:BenefitsPaidOrPayable
2569	Contributions of sponsors	Concept (Monetary)	For Period	Debit	ifrs-full:ContributionsToPlanByEmployerNetDefinedBenefitLiabilityAsset
2570	Contributions of participants	Concept (Monetary)	For Period	Debit	ifrs-full:ContributionsToPlanByPlanParticipantsNetDefinedBenefitLiabilityAsset
2571	Effects on asset ceiling	Concept (Monetary)	For Period	Debit	ifrs-full:GainLossOnChangesInEffectOfLimitingNetDefinedBenefitAssetToAssetCeiling
2572	Balance arising from the Corpbanca acquisition	Concept (Monetary)	For Period	Debit	itub:BalanceArisingFromAcquisition
2573	Exchange Variation	Concept (Monetary)	For Period	Credit	itub:ExchangeVariation
2574	Remeasurements	Concept (Monetary)	For Period	Debit	ifrs-full:GainLossOnRemeasurementOfNetDefinedBenefitLiabilityAsset
2575	At the end of the period	Concept (Monetary)	As Of	Credit	ifrs-full:LiabilityAssetOfDefinedBenefitPlans
2576	Actual return on assets	Concept (Monetary)	For Period	Debit	ifrs-full:ReturnOnPlanAssetsNetDefinedBenefitLiabilityAsset
2577	1185 - Disclosure - Post-Employment Benefits - Summary of Changes in Net Amount Recognized in Balance Sheet (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosurePostEmploymentBenefitsSummaryOfChangesInNetAmountRecognizedInBalanceSheetParenthetical
2578	Implied Table	Table	*	*	implied:Table
2579	Disclosure of defined benefit plans [abstract]	Abstract			ifrs-full:DisclosureOfDefinedBenefitPlansAbstract
2580	Discount rate	Concept (Percent)	As Of		ifrs-full:ActuarialAssumptionOfDiscountRates
2581	1186 - Disclosure - Post-Employment Benefits - Summary of Estimate for Payment of Benefits (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosurePostEmploymentBenefitsSummaryOfEstimateForPaymentOfBenefits
2582	Disclosure of defined benefit plans [table]	Table	*	*	ifrs-full:DisclosureOfDefinedBenefitPlansTable
2583	Defined benefit plans [axis]	Axis			ifrs-full:DefinedBenefitPlansAxis
2584	Defined benefit plans [member]	Member			ifrs-full:DefinedBenefitPlansMember
2585	Other post-employment benefit [Member]	Member			itub:OtherPostEmploymentBenefitMember
2586	Disclosure of defined benefit plans [line items]	LineItems			ifrs-full:DisclosureOfDefinedBenefitPlansLineItems
2587	2018	Concept (Monetary)	For Period	Debit	itub:EstimatedPaymentsForEmploymentBenefitsRemainderOfFiscalYear
2588	2019	Concept (Monetary)	For Period	Debit	itub:EstimatedPaymentsForEmploymentBenefitsDueInYearTwo
2589	2020	Concept (Monetary)	For Period	Debit	itub:EstimatedPaymentsForEmploymentBenefitsDueInYearThree
2590	2021	Concept (Monetary)	For Period	Debit	itub:EstimatedPaymentsForEmploymentBenefitsDueInYearFour
2591	2022	Concept (Monetary)	For Period	Debit	itub:EstimatedPaymentsForEmploymentBenefitsDueInYearFive
2592	2023 to 2027	Concept (Monetary)	For Period	Debit	itub:EstimatedPaymentsForBenefitsDueInYearsSixToTen
2593	1187 - Disclosure - Post-Employment Benefits - Summary of Sensitivity of Defined Benefit Obligation (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosurePostEmploymentBenefitsSummaryOfSensitivityOfDefinedBenefitObligation
2594	Implied Table	Table	*	*	implied:Table
2595	Disclosure of sensitivity analysis for actuarial assumptions [abstract]	Abstract			ifrs-full:DisclosureOfSensitivityAnalysisForActuarialAssumptionsAbstract
2596	Effects on actuarial liabilities of the plan, decrease	Concept (Monetary)	As Of	Credit	ifrs-full:IncreaseDecreaseInDefinedBenefitObligationDueToReasonablyPossibleDecreaseInActuarialAssumption
2597	Effects on actuarial liabilities of the plan, increase	Concept (Monetary)	As Of	Credit	ifrs-full:IncreaseDecreaseInDefinedBenefitObligationDueToReasonablyPossibleIncreaseInActuarialAssumption
2598	Percentage of actuarial liabilities, decrease	Concept (Percent)	As Of		ifrs-full:PercentageOfReasonablyPossibleDecreaseInActuarialAssumption
2599	Percentage of actuarial liabilities, increase	Concept (Percent)	As Of		ifrs-full:PercentageOfReasonablyPossibleIncreaseInActuarialAssumption
2600	Effect recognized in stockholder's equity, decrease	Concept (Monetary)	As Of	Credit	itub:DecreaseInDefinedBenefitObligationRecognizedInStockholdersEquity
2601	Effect recognized in stockholder's equity, increase	Concept (Monetary)	As Of	Credit	itub:IncreaseInDefinedBenefitObligationRecognizedInStockholdersEquity
2602	1188 - Disclosure - Post-Employment Benefits - Summary of Change in Net Amount Recognized in Balance Sheet (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosurePostEmploymentBenefitsSummaryOfChangeInNetAmountRecognizedInBalanceSheet
2603	Disclosure of net defined benefit liability (asset) [table]	Table	*	*	ifrs-full:DisclosureOfNetDefinedBenefitLiabilityAssetTable
2604	Net defined benefit liability (asset) [axis]	Axis			ifrs-full:NetDefinedBenefitLiabilityAssetAxis
2605	Net defined benefit liability (asset) [member]	Member			ifrs-full:NetDefinedBenefitLiabilityAssetMember
2606	Plan assets [member]	Member			ifrs-full:PlanAssetsMember
2607	Effect of asset ceiling [member]	Member			ifrs-full:EffectOfAssetCeilingMember
2608	Defined benefit plans [axis]	Axis			ifrs-full:DefinedBenefitPlansAxis
2609	Defined benefit plans [member]	Member			ifrs-full:DefinedBenefitPlansMember
2610	Defined contribution plans [Member]	Member			itub:DefinedContributionPlansMember
2611	Other post-employment benefit [Member]	Member			itub:OtherPostEmploymentBenefitMember
2612	Disclosure of net defined benefit liability (asset) [line items]	LineItems			ifrs-full:DisclosureOfNetDefinedBenefitLiabilityAssetLineItems
2613	At the beginning of the period	Concept (Monetary)	As Of	Credit	ifrs-full:LiabilityAssetOfDefinedBenefitPlans
2614	Interest cost	Concept (Monetary)	For Period	Credit	ifrs-full:InterestExpenseIncomeNetDefinedBenefitLiabilityAsset
2615	Contribution	Concept (Monetary)	For Period	Debit	ifrs-full:ContributionsToPlanNetDefinedBenefitLiabilityAsset
2616	Benefits paid	Concept (Monetary)	For Period	Debit	ifrs-full:BenefitsPaidOrPayable
2617	Receivables - allocation of funds	Concept (Monetary)	For Period	Debit	ifrs-full:PaymentsFromPlanNetDefinedBenefitLiabilityAsset
2618	Effects on asset ceiling	Concept (Monetary)	For Period	Debit	ifrs-full:GainLossOnChangesInEffectOfLimitingNetDefinedBenefitAssetToAssetCeiling
2619	Remeasurements	Concept (Monetary)	For Period	Debit	ifrs-full:GainLossOnRemeasurementOfNetDefinedBenefitLiabilityAsset
2620	At the end of the period	Concept (Monetary)	As Of	Credit	ifrs-full:LiabilityAssetOfDefinedBenefitPlans
2621	1189 - Disclosure - Post-Employment Benefits - Summary of Assumptions About Medical Care Cost (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosurePostEmploymentBenefitsSummaryOfAssumptionsAboutMedicalCareCost
2622	Disclosure of defined benefit plans [table]	Table	*	*	ifrs-full:DisclosureOfDefinedBenefitPlansTable
2623	Actuarial assumptions [axis]	Axis			ifrs-full:ActuarialAssumptionsAxis
2624	Actuarial assumptions [member]	Member			ifrs-full:ActuarialAssumptionsMember
2625	Medical care cost [Member]	Member			ifrs-full:ActuarialAssumptionOfMedicalCostTrendRatesMember
2626	Net defined benefit liability (asset) [axis]	Axis			ifrs-full:NetDefinedBenefitLiabilityAssetAxis
2627	Net defined benefit liability (asset) [member]	Member			ifrs-full:NetDefinedBenefitLiabilityAssetMember
2628	Service Cost And Interest Cost [Member]	Member			itub:ServiceCostAndInterestCostMember
2629	Present value of defined benefit obligation [member]	Member			ifrs-full:PresentValueOfDefinedBenefitObligationMember
2630	Disclosure of defined benefit plans [line items]	LineItems			ifrs-full:DisclosureOfDefinedBenefitPlansLineItems
2631	1% increase	Concept (Percent)	As Of		ifrs-full:PercentageOfReasonablyPossibleIncreaseInActuarialAssumption
2632	1% decrease	Concept (Percent)	As Of		ifrs-full:PercentageOfReasonablyPossibleDecreaseInActuarialAssumption
2633	1190 - Disclosure - Insurance contracts - Summary of Main Insurance lines (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInsuranceContractsSummaryOfMainInsuranceLines
2634	Disclosure of Types of Insurance Contracts [Table]	Table	*	*	ifrs-full:DisclosureOfTypesOfInsuranceContractsTable
2635	Types of insurance contracts [axis]	Axis			ifrs-full:TypesOfInsuranceContractsAxis
2636	Types of insurance contracts [member]	Member			ifrs-full:InsuranceContractsMember
2637	Group accident insurance [Member]	Member			itub:GroupAccidentInsuranceMember
2638	Individual accident [Member]	Member			itub:IndividualAccidentMember
2639	Commercial Multiple Peril [Member]	Member			itub:CommercialMultiplePerilMember
2640	Internal Credit [Member]	Member			itub:InternalCreditMember
2641	Mandatory personal injury caused by motor vehicle [Member]	Member			itub:MandatoryInsuranceForPersonalInjuryCausedByMotorVehiclesMember
2642	Serious or Terminal Diseases [Member]	Member			itub:SeriousOrTerminalDiseasesMember
2643	Extended Warranty Assets [Member]	Member			itub:ExtendedWarrantyAssetsMember
2644	Credit Life [Member]	Member			itub:CreditLifeMember
2645	Multiple Risks [Member]	Member			itub:MultipleRisksMember
2646	Home Insurance in Market Policies Credit Life [Member]	Member			itub:HomeInsuranceInMarketPoliciesCreditLifeMember
2647	Group life [Member]	Member			itub:GroupLifeMember
2648	Disclosure of Types of Insurance Contracts [Line Items]	LineItems			ifrs-full:DisclosureOfTypesOfInsuranceContractsLineItems
2649	Loss ratio	Concept (Percent)	For Period		itub:InsuranceLossRatio
2650	Sales ratio	Concept (Percent)	For Period		itub:InsuranceSalesRatio
2651	1191 - Disclosure - Insurance contracts - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInsuranceContractsAdditionalInformation
2652	Disclosure of Types of Insurance Contracts [Table]	Table	*	*	ifrs-full:DisclosureOfTypesOfInsuranceContractsTable
2653	Range [axis]	Axis			ifrs-full:RangeAxis
2654	Ranges [member]	Member			ifrs-full:RangesMember
2655	Top of range [member]	Member			ifrs-full:TopOfRangeMember
2656	Associates [axis]	Axis			ifrs-full:SignificantInvestmentsInAssociatesAxis
2657	Entity's total for associates [member]	Member			ifrs-full:EntitysTotalForAssociatesMember
2658	Munich Re do Brasil [Member]	Member			itub:MunichReDoBrasilMember
2659	General Reinsurance AG [Member]	Member			itub:GeneralReinsuranceAgMember
2660	IRB-Brasil Resseguros S.A. [Member]	Member			itub:IRBBrasilRessegurosSAMember
2661	Types of risks [axis]	Axis			ifrs-full:TypesOfRisksAxis
2662	Risks [member]	Member			ifrs-full:TypesOfRisksMember
2663	Credit risk [member]	Member			ifrs-full:CreditRiskMember
2664	Disclosure of Types of Insurance Contracts [Line Items]	LineItems			ifrs-full:DisclosureOfTypesOfInsuranceContractsLineItems
2665	Number of private pension products	Concept (Integer)	For Period		itub:NumberOfPensionPlans
2666	Percentage of income tax deduction	Concept (Percent)	As Of		itub:PercentageOfIncomeTaxDeduction
2667	Percentage of reinsurance premiums operations	Concept (Percent)	For Period		itub:PercentageOfReinsurancePremiumsOperations
2668	Percentage of social security operations related to reinsurance premiums	Concept (Percent)	For Period		itub:PercentageOfSocialSecurityOperationsRelatedToReinsurancePremiums
2669	Revaluation term of reinsurance assets	Concept (xbrli:durationItemType)	For Period		itub:RevaluationTermOfReinsuranceAssets
2670	1192 - Disclosure - Insurance contracts - Summary of Revenue from Main Insurance and Private Pension (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInsuranceContractsSummaryOfRevenueFromMainInsuranceAndPrivatePension
2671	Disclosure of Types of Insurance Contracts [Table]	Table	*	*	ifrs-full:DisclosureOfTypesOfInsuranceContractsTable
2672	Types of insurance contracts [axis]	Axis			ifrs-full:TypesOfInsuranceContractsAxis
2673	Types of insurance contracts [member]	Member			ifrs-full:InsuranceContractsMember
2674	Group accident insurance [Member]	Member			itub:GroupAccidentInsuranceMember
2675	Individual accident [Member]	Member			itub:IndividualAccidentMember
2676	Commercial Multiple Peril [Member]	Member			itub:CommercialMultiplePerilMember
2677	Internal Credit [Member]	Member			itub:InternalCreditMember
2678	Mandatory personal injury caused by motor vehicle [Member]	Member			itub:MandatoryInsuranceForPersonalInjuryCausedByMotorVehiclesMember
2679	Serious or Terminal Diseases [Member]	Member			itub:SeriousOrTerminalDiseasesMember
2680	Extended Warranty Assets [Member]	Member			itub:ExtendedWarrantyAssetsMember
2681	Disability Savings Pension [Member]	Member			itub:DisabilitySavingsPensionMember
2682	Plan Generator of Benefits [Member]	Member			itub:PlanGeneratorOfBenefitsMember
2683	Credit Life [Member]	Member			itub:CreditLifeMember
2684	Multiple Risks [Member]	Member			itub:MultipleRisksMember
2685	Home Insurance in Market Policies Credit Life [Member]	Member			itub:HomeInsuranceInMarketPoliciesCreditLifeMember
2686	Traditional Insurance [Member]	Member			itub:TraditionalInsuranceMember
2687	VGBL [Member]	Member			itub:VgblMember
2688	Group life [Member]	Member			itub:GroupLifeMember
2689	Other Lines [Member]	Member			itub:OtherLinesMember
2690	Disclosure of Types of Insurance Contracts [Line Items]	LineItems			ifrs-full:DisclosureOfTypesOfInsuranceContractsLineItems
2691	Premiums and contributions issued	Concept (Monetary)	For Period	Debit	itub:InsurancePremiumsAndContributionsIssued
2692	Reinsurance	Concept (Monetary)	For Period	Credit	itub:ReinsurancePremium
2693	Retained premiums and contributions	Concept (Monetary)	For Period	Debit	itub:InsurancePremiumsAndContributionsRetained
2694	1193 - Disclosure - Insurance contracts - Summary of Changes in Technical Provisions (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInsuranceContractsSummaryOfChangesInTechnicalProvisions
2695	Disclosure of other provisions [table]	Table	*	*	ifrs-full:DisclosureOfOtherProvisionsTable
2696	Types of insurance contracts [axis]	Axis			ifrs-full:TypesOfInsuranceContractsAxis
2697	Types of insurance contracts [member]	Member			ifrs-full:InsuranceContractsMember
2698	Insurance [member]	Member			itub:InsuranceMember
2699	Private Pension [Member]	Member			itub:PrivatePensionMember
2700	Property Individuals And Life Insurance [Member]	Member			itub:PropertyIndividualsAndLifeInsuranceMember
2701	Life With Survivor Benefits [Member]	Member			itub:LifeWithSurvivorBenefitsMember
2702	Disclosure of other provisions [line items]	LineItems			ifrs-full:DisclosureOfOtherProvisionsLineItems
2703	Opening balance	Concept (Monetary)	As Of	Credit	itub:GrossLiabilitiesArisingFromInsuranceContracts
2704	Additions arising from premiums / contribution	Concept (Monetary)	For Period	Credit	ifrs-full:AcquisitionsThroughBusinessCombinationsLiabilitiesUnderInsuranceContractsAndReinsuranceContractsIssued
2705	Deferral of risk	Concept (Monetary)	For Period	Debit	itub:DecreaseInDeferralOfRisk
2706	Payment of claims / benefits	Concept (Monetary)	For Period	Credit	itub:PaymentOfClaimsAndBenefitsOutOfInsuranceContracts
2707	Reported claims	Concept (Monetary)	For Period	Credit	itub:InsuranceClaimsReportedByPolicyholders
2708	Redemptions	Concept (Monetary)	For Period	Credit	itub:DisposalsAndRedemptions
2709	Net portability	Concept (Monetary)	For Period	Credit	itub:IncreaseDecreesInNetPortability
2710	Adjustment of reserves and financial surplus	Concept (Monetary)	For Period	Credit	itub:AdjustmentOfReservesAndFinancialSurplus
2711	Corporate Reorganization	Concept (Monetary)	For Period	Debit	itub:ReorganizationExpensesReversals
2712	Other (recognition / reversal)	Concept (Monetary)	For Period	Credit	itub:OtherLiabilitiesUnderInsuranceContracts
2713	Reserves for insurance and private pension	Concept (Monetary)	As Of	Credit	itub:GrossLiabilitiesArisingFromInsuranceContracts
2714	Unearned premiums	Concept (Monetary)	As Of	Credit	ifrs-full:UnearnedPremiums
2715	Mathematical reserve for benefits to be granted and benefits granted	Concept (Monetary)	For Period	Credit	itub:MathematicalReserveForBenefitsToBegrantedAndBenefitsGranted
2716	Redemptions and Other Unsettled Amounts	Concept (Monetary)	For Period	Debit	itub:RedemptionsAndOtherUnsettledAmounts
2717	Financial surplus	Concept (Monetary)	For Period	Credit	itub:AdjustmentOfFinancialSurplus
2718	Unsettled claims	Concept (Monetary)	As Of	Credit	itub:NetReinsuranceReserveForUnsettledClaims
2719	IBNR	Concept (Monetary)	As Of	Credit	ifrs-full:ClaimsIncurredButNotReported
2720	Administrative and Related Expenses	Concept (Monetary)	For Period	Debit	itub:AdministrativeAndRelatedExpenses
2721	Other	Concept (Monetary)	As Of	Credit	ifrs-full:OtherProvisions
2722	Total	Concept (Monetary)	As Of	Credit	ifrs-full:LiabilitiesArisingFromInsuranceContracts
2723	1194 - Disclosure - Insurance contracts - Summary of Gross Reinsurance Assets (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInsuranceContractsSummaryOfGrossReinsuranceAssets
2724	Disclosure of reinsurance assets [Table]	Table	*	*	itub:DisclosureOfReinsuranceAssetsTable
2725	Types of insurance contracts [axis]	Axis			ifrs-full:TypesOfInsuranceContractsAxis
2726	Types of insurance contracts [member]	Member			ifrs-full:InsuranceContractsMember
2727	Gross Of Reinsurance [Member]	Member			itub:GrossOfReinsuranceMember
2728	Maturity [axis]	Axis			ifrs-full:MaturityAxis
2729	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
2730	Current [Member]	Member			ifrs-full:NotLaterThanOneYearMember
2731	Non-current [Member]	Member			ifrs-full:LaterThanOneYearMember
2732	Disclosure of reinsurance assets [Line Items]	LineItems			itub:DisclosureOfReinsuranceAssetsLineItems
2733	Balance to be amortized	Concept (Monetary)	As Of	Debit	ifrs-full:ReinsuranceAssets
2734	Beginning balance	Concept (Monetary)	As Of	Debit	ifrs-full:ReinsuranceAssets
2735	Increase	Concept (Monetary)	For Period	Debit	ifrs-full:IncreaseDecreaseInReinsuranceAssets
2736	Amortization	Concept (Monetary)	For Period	Debit	ifrs-full:AmortisationOfGainsAndLossesArisingOnBuyingReinsurance
2737	Balance at 12/31/2017	Concept (Monetary)	As Of	Debit	ifrs-full:ReinsuranceAssets
2738	1195 - Disclosure - Insurance Contracts - Summary of Gross of Reinsurance (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInsuranceContractsSummaryOfGrossOfReinsurance
2739	Disclosure of Reinsurance Transactions [Table]	Table	*	*	itub:DisclosureOfReinsuranceTransactionsTable
2740	Amounts arising from insurance contracts [axis]	Axis			ifrs-full:AmountsArisingFromInsuranceContractsAxis
2741	Net amount arising from insurance contracts [member]	Member			ifrs-full:NetAmountArisingFromInsuranceContractsMember
2742	Administratives claims [member]	Member			itub:AdministrativesClaimsMember
2743	Judicial claims [member]	Member			itub:JudicialClaimsMember
2744	Types of insurance contracts [axis]	Axis			ifrs-full:TypesOfInsuranceContractsAxis
2745	Types of insurance contracts [member]	Member			ifrs-full:InsuranceContractsMember
2746	Gross Of Reinsurance [Member]	Member			itub:GrossOfReinsuranceMember
2747	Net Reinsurance [Member]	Member			itub:NetReinsuranceMember
2748	Maturity [axis]	Axis			ifrs-full:MaturityAxis
2749	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
2750	Current [Member]	Member			ifrs-full:NotLaterThanOneYearMember
2751	Later than one year and not later than two years [member]	Member			ifrs-full:LaterThanOneYearAndNotLaterThanTwoYearsMember
2752	Later than two years and not later than three years [member]	Member			ifrs-full:LaterThanTwoYearsAndNotLaterThanThreeYearsMember
2753	Later than three years and not later than four years [member]	Member			ifrs-full:LaterThanThreeYearsAndNotLaterThanFourYearsMember
2754	Later than four years and not later than five years [member]	Member			ifrs-full:LaterThanFourYearsAndNotLaterThanFiveYearsMember
2755	Disclosure of Reinsurance Transactions [Line Items]	LineItems			itub:DisclosureOfReinsuranceTransactionsLineItems
2756	At the end of reporting period	Concept (Monetary)	As Of	Credit	itub:GrossReinsuranceReportingPeriod
2757	Reserve for unsettled claims	Concept (Monetary)	As Of	Credit	itub:NetReinsuranceReserveForUnsettledClaims
2758	At the end of reporting period	Concept (Monetary)	As Of	Credit	itub:NetReinsuranceReportingPeriod
2759	Reserve for unsettled claims	Concept (Monetary)	As Of	Credit	itub:GrossReinsuranceReserveForUnsettledClaims
2760	Current estimate	Concept (Monetary)	As Of	Credit	itub:GrossReinsuranceCurrentEstimate
2761	Current estimate	Concept (Monetary)	As Of	Credit	itub:NetReinsuranceCurrentEstimate
2762	DPVAT operations	Concept (Monetary)	As Of	Credit	ifrs-full:ClaimsReportedByPolicyholders
2763	IBNER	Concept (Monetary)	As Of	Credit	ifrs-full:ClaimsIncurredButNotReported
2764	Accumulated payments through base date	Concept (Monetary)	As Of	Credit	itub:GrossReinsuranceAccumulatedPaymentsThroughBaseDate
2765	Reinsurance	Concept (Monetary)	As Of	Debit	itub:ReinsuranceClaims
2766	Accumulated payments through base date to current date	Concept (Monetary)	As Of	Credit	itub:GrossReinsuranceAccumulatedPaymentsFromBaseDatetoCurrentDate
2767	Retrocession and other estimates	Concept (Monetary)	As Of	Credit	itub:NetReinsuranceRetrocessionAndOtherEstimates
2768	Liabilities recognized in the balance sheet	Concept (Monetary)	As Of	Credit	itub:GrossReinsuranceLiabilitiesRecognizedInBalanceSheet
2769	Accumulated liabilities recognized in the balance sheet	Concept (Monetary)	As Of	Credit	itub:AccumulatedReinsuranceLiabilitiesRecognizedInBalanceSheet
2770	Liabilities in relation to prior years	Concept (Monetary)	As Of	Credit	itub:GrossReinsuranceLiabilitiesRelationToPriorYears
2771	Liabilities in relation to prior years	Concept (Monetary)	As Of	Credit	itub:NetReinsuranceLiabilitiesRelationToPriorYears
2772	Liability claims presented in the development table	Concept (Monetary)	As Of	Credit	itub:NetReinsuranceLiabilityClaimsPresentedInTheDevelopment
2773	Liability claims presented in the development table	Concept (Monetary)	As Of	Credit	itub:GrossReinsuranceLiabilityClaimsPresentedInTheDevelopment
2774	1196 - Disclosure - Insurance Contracts - Summary of Risks of Insurance and Private Pension (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInsuranceContractsSummaryOfRisksOfInsuranceAndPrivatePension
2775	Disclosure Of Insurance Risk [Table]	Table	*	*	itub:DisclosureOfInsuranceRiskTable
2776	Categories of related parties [axis]	Axis			ifrs-full:CategoriesOfRelatedPartiesAxis
2777	Entity's total for related parties [member]	Member			ifrs-full:EntitysTotalForRelatedPartiesMember
2778	ITAU UNIBANCO HOLDING [Member]	Member			itub:ItauUnibancoHoldingMember
2779	Types of insurance contracts [axis]	Axis			ifrs-full:TypesOfInsuranceContractsAxis
2780	Types of insurance contracts [member]	Member			ifrs-full:InsuranceContractsMember
2781	Mandatory personal injury caused by motor vehicle [Member]	Member			itub:MandatoryInsuranceForPersonalInjuryCausedByMotorVehiclesMember
2782	Extended warranty [Member]	Member			itub:ExtendedWarrantyMember
2783	Group accident insurance [Member]	Member			itub:GroupAccidentInsuranceMember
2784	Individual accident [Member]	Member			itub:IndividualAccidentMember
2785	Group life [Member]	Member			itub:GroupLifeMember
2786	Disclosure of insurance risk [Line Items]	LineItems			itub:DisclosureOfInsuranceRiskLineItems
2787	Insurance premiums	Concept (Monetary)	For Period	Credit	itub:ReinsurancePremium
2788	Retained premium	Concept (Monetary)	For Period	Debit	itub:RetainedPremiums
2789	Retention	Concept (Percent)	For Period		itub:RetentionPercentage
2790	1197 - Disclosure - Insurance Contracts -Summary of Sensitivity Analysis Presented in Relation to Insurance Operations Demonstrate Impact on Cash Flows Market Value (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInsuranceContractsSummaryOfSensitivityAnalysisPresentedInRelationToInsuranceOperationsDemonstrateImpactOnCashFlowsMarketValue
2791	Disclosure of sensitivity analysis market risk [Table]	Table	*	*	itub:DisclosureOfSensitivityAnalysisMarketRiskTable
2792	Types of risks [axis]	Axis			ifrs-full:TypesOfRisksAxis
2793	Risks [member]	Member			ifrs-full:TypesOfRisksMember
2794	Currency, commodities, and ratios [Member]	Member			ifrs-full:MarketRiskMember
2795	Classes of financial instruments [axis]	Axis			ifrs-full:ClassesOfFinancialInstrumentsAxis
2796	Financial instruments, class [member]	Member			ifrs-full:ClassesOfFinancialInstrumentsMember
2797	NTN-C [Member]	Member			itub:NTNCGovernmentSecuritiesMember
2798	NTN-B [Member]	Member			itub:NTNBGovernmentSecuritiesMember
2799	LTN [Member]	Member			itub:LTNGovernmentSecuritiesMember
2800	Indexed to IPCA [Member]	Member			itub:PrivateSecuritiesIndexedToIPCAMember
2801	Indexed to PRE [Member]	Member			itub:PrivateSecuritiesIndexedToPREMember
2802	Shares [Member]	Member			itub:SharesMember
2803	Floating assets [Member]	Member			itub:FloatingAssetsMember
2804	Under agreements to resell [Member]	Member			itub:UnderAgreementsToResellMember
2805	Disclosure of sensitivity analysis market risk [Line Items]	LineItems			itub:DisclosureOfSensitivityAnalysisMarketRiskLineItems
2806	Account balance	Concept (Monetary)	As Of		ifrs-full:RiskExposureAssociatedWithInstrumentsSharingCharacteristic
2807	DV01	Concept (Pure)	For Period		itub:DeltaVariationRate
2808	1198 - Disclosure - Insurance Contracts -Summary of Liquidity Risk (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInsuranceContractsSummaryOfLiquidityRisk
2809	Disclosure of liquidity risk [Table]	Table	*	*	itub:DisclosureOfLiquidityRiskTable
2810	Types of share-based payment arrangements [axis]	Axis			ifrs-full:TypesOfSharebasedPaymentArrangementsAxis
2811	Share-based payment arrangements [member]	Member			ifrs-full:SharebasedPaymentArrangementsMember
2812	LFT, repurchase agreements, NTN-B, CDB, LF and debentures [Member]	Member			itub:LFTRepurchaseAgreementsNTNBCDBLFAndDebenturesMember
2813	LFT, repurchase agreements, NTN-B, CDB and debentures [Member]	Member			itub:LFTRepurchaseAgreementsNTNBCDBAndDebenturesMember
2814	LFT, repurchase agreements, LTN, NTN-B, NTN-C, NTN-F, CDB, LF and debentures [Member]	Member			itub:LFTRepurchaseAgreementsLTNNTNBNTNCNTNFCDBLFAndDebenturesMember
2815	LFT, repurchase agreements, NTN-B, NTN-C, Debentures [Member]	Member			itub:LFTRepurchaseAgreementsNTNBNTNCDebenturesMember
2816	LFT, repurchase agreements, NTN-B, NTN-C, CDB, LF and debentures [Member]	Member			itub:LFTRepurchaseAgreementsNTNBNTNCCDBLFAndDebenturesMember
2817	Classes of assets [axis]	Axis			ifrs-full:ClassesOfAssetsAxis
2818	Assets [member]	Member			ifrs-full:ClassesOfAssetsMember
2819	Backing asset [Member]	Member			itub:BackingAssetMember
2820	Types of insurance contracts [axis]	Axis			ifrs-full:TypesOfInsuranceContractsAxis
2821	Types of insurance contracts [member]	Member			ifrs-full:InsuranceContractsMember
2822	Insurance Operations [Member]	Member			itub:InsuranceOperationsMember
2823	Pension plan, VGBL and individual life operations [Member]	Member			itub:PensionPlanVGBLAndIndividualLifeOperationsMember
2824	Classes of liabilities [axis]	Axis			ifrs-full:ClassesOfLiabilitiesAxis
2825	Liabilities [member]	Member			ifrs-full:LiabilitiesMember
2826	Unearned Premiums [Member]	Member			itub:UnearnedPremiumsMember
2827	IBNR, PDR e PSL [Member]	Member			itub:IBNRPDRePSLMember
2828	Other Provision [member]	Member			itub:OtherProvisionMember
2829	Related expenses [Member]	Member			itub:RelatedExpensesMember
2830	Unsettled Claims [Member]	Member			itub:UnsettledClaimsMember
2831	IBNR [Member]	Member			itub:IBNRMember
2832	Redemptions And Other Unsettled Amounts [Member]	Member			itub:RedemptionsAndOtherUnsettledAmountsMember
2833	Mathematical Reserve For Benefits Granted [Member]	Member			itub:MathematicalReserveForBenefitsGrantedMember
2834	Mathematical reserve for benefits to be granted - PGBL/ VGBL [Member]	Member			itub:MathematicalReserveForBenefitsToBeGrantedPGBLOrVGBLMember
2835	Mathematical reserve for benefits to be granted - traditional [Member]	Member			itub:MathematicalReserveForBenefitsToBeGrantedTraditionalMember
2836	Financial surplus [Member]	Member			itub:FinancialSurplusMember
2837	Disclosure Of Liquidity Risk [Line Items]	LineItems			itub:DisclosureOfLiquidityRiskLineItems
2838	Liabilities (Amount)	Concept (Monetary)	As Of	Credit	ifrs-full:LiabilitiesArisingFromInsuranceContracts
2839	Liabilities(Duration in months)	Concept (Text/String)	For Period		itub:PeriodOfInsuranceLiabilities
2840	Assets(Duration in months)	Concept (Text/String)	For Period		itub:PeriodOfInsuranceAssets
2841	1199 - Disclosure - Insurance Contracts - Summary of Risk Level of Financial Assets (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInsuranceContractsSummaryOfRiskLevelOfFinancialAssets
2842	Disclosure of risk level of financial assets [Table]	Table	*	*	itub:DisclosureOfRiskLevelOfFinancialAssetsTable
2843	Types of financial assets [axis]	Axis			ifrs-full:TypesOfFinancialAssetsAxis
2844	Financial assets, type [member]	Member			ifrs-full:FinancialAssetsTypeMember
2845	Insurance financial assets [member]	Member			itub:InsuranceFinancialAssetsMember
2846	Types of risks [axis]	Axis			ifrs-full:TypesOfRisksAxis
2847	Risks [member]	Member			ifrs-full:TypesOfRisksMember
2848	Lower risk [Member]	Member			itub:LowerRiskMember
2849	Satisfactory [Member]	Member			itub:SatisfactoryRiskMember
2850	Higher Risk [Member]	Member			itub:HigherRiskMember
2851	Disclosure of risk level of financial assets [Line Items]	LineItems			itub:DisclosureOfRiskLevelOfFinancialAssetsLineItems
2852	Interbank deposits and securities purchased under agreements to resell, percentage	Concept (Percent)	As Of		itub:PercentageOfInterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResell
2853	Held-for-trading-financial assets, percentage	Concept (Percent)	As Of		itub:PercentageOfHeldForTradingFinancialAssets
2854	Derivatives assets, percentage	Concept (Percent)	As Of		itub:PercentageOfDerivativeFinancialAssets
2855	Available-for-sale financial assets, percentage	Concept (Percent)	As Of		itub:PercentageOfFinancialAssetsAvailableForSale
2856	Held-to-maturity financial assets, percentage	Concept (Percent)	As Of		itub:PercentageOfHeldToMaturityFinancialAssets
2857	Total, percentage	Concept (Percent)	As Of		itub:PercentageOfFinancialAssets
2858	Interbank deposits and securities purchased under agreements to resell	Concept (Monetary)	As Of	Debit	itub:InterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResell
2859	Held-for-trading-financial assets	Concept (Monetary)	As Of	Debit	itub:FinancialAssetsHeldForTrading
2860	Derivatives assets	Concept (Monetary)	As Of	Debit	ifrs-full:DerivativeFinancialAssets
2861	Available-for-sale financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAvailableforsale
2862	Held-to-maturity financial assets	Concept (Monetary)	As Of	Debit	itub:HeldToMaturityFinancialAssets
2863	Total	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssets
2864	1200 - Disclosure - Insurance Contracts - Summary of Changes in Balances of Transactions With Reinsurance Companies (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInsuranceContractsSummaryOfChangesInBalancesOfTransactionsWithReinsuranceCompanies
2865	Implied Table	Table	*	*	implied:Table
2866	Disclosure of changes in balances of transactions with reinsurance [Abstract]	Abstract			itub:DisclosureOfChangesInBalancesOfTransactionsWithReinsuranceAbstract
2867	Opening balance, credits	Concept (Monetary)	As Of	Credit	itub:ReinsuranceLiabilities
2868	Issued contracts, credits	Concept (Monetary)	For Period	Credit	itub:ReinsuranceLiabilitiesContractsIssued
2869	Recoverable claims, credits	Concept (Monetary)	For Period	Credit	itub:ReinsuranceLiabilitiesRecoverableClaims
2870	Prepayments / payments to reinsurer, credits	Concept (Monetary)	For Period	Credit	itub:ReinsuranceLiabilitiesRecoverableClaimsPrepaymentOrPaymentsToReinsurer
2871	Other increase / reversal, credits	Concept (Monetary)	For Period	Credit	itub:IncreaseDecreaseThroughOtherChangesReinsuranceLiabilities
2872	Closing balance, credits	Concept (Monetary)	As Of	Credit	itub:ReinsuranceLiabilities
2873	Beginning balance	Concept (Monetary)	As Of	Debit	ifrs-full:ReinsuranceAssets
2874	Issued contracts, debits	Concept (Monetary)	For Period	Debit	itub:ReinsuranceAssetsContractsIssued
2875	Recoverable claims, debits	Concept (Monetary)	For Period	Debit	itub:ReinsuranceAssetsRecoverableClaims
2876	Prepayments / payments to reinsurer, debits	Concept (Monetary)	For Period	Debit	itub:ReinsuranceAssetsRecoverableClaimsPrepaymentOrPaymentsToReinsurer
2877	Other increase / reversal, debits	Concept (Monetary)	For Period	Debit	ifrs-full:IncreaseDecreaseThroughOtherChangesReinsuranceAssets
2878	Balance at 12/31/2017	Concept (Monetary)	As Of	Debit	ifrs-full:ReinsuranceAssets
2879	1201 - Disclosure - Insurance Contracts - Summary of Technical Reserves with Reinsurance Assets (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInsuranceContractsSummaryOfTechnicalReservesWithReinsuranceAssets
2880	Implied Table	Table	*	*	implied:Table
2881	Disclosure of technical reserves with reinsurance assets [Abstract]	Abstract			itub:DisclosureOfTechnicalReservesWithReinsuranceAssetsAbstract
2882	Reinsurance claims	Concept (Monetary)	As Of	Debit	itub:ReinsuranceClaims
2883	Reinsurance premiums	Concept (Monetary)	As Of	Debit	itub:ReinsurancePremiums
2884	Closing balance	Concept (Monetary)	As Of	Debit	itub:ReinsuranceAssetsAndTechnicalReserves
2885	1202 - Disclosure - Insurance Contracts - Summary of Changes in Balances of Technical Reserves for Reinsurance Claims (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInsuranceContractsSummaryOfChangesInBalancesOfTechnicalReservesForReinsuranceClaims
2886	Implied Table	Table	*	*	implied:Table
2887	Disclosure of changes in balances of technical reserves for reinsurance claims [Abstract]	Abstract			itub:DisclosureOfChangesInBalancesOfTechnicalReservesForReinsuranceClaimsAbstract
2888	Opening balance	Concept (Monetary)	As Of	Debit	itub:ReinsuranceClaims
2889	Reported claims	Concept (Monetary)	For Period	Debit	itub:ReinsuranceReportedClaims
2890	Paid claims	Concept (Monetary)	For Period	Credit	itub:ReinsurancePaidClaims
2891	Other increase / reversal	Concept (Monetary)	For Period	Debit	itub:ReinsuranceClaimsOtherIncreaseOrReversal
2892	Monetary adjustment and interest of claims	Concept (Monetary)	For Period	Debit	itub:MonetaryAdjustmentAndInterestOfReinsuranceClaims
2893	Closing balance	Concept (Monetary)	As Of	Debit	itub:ReinsuranceClaims
2894	1203 - Disclosure - Insurance Contracts - Summary of Changes in Balances of Technical Reserves for Reinsurance Premiums (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInsuranceContractsSummaryOfChangesInBalancesOfTechnicalReservesForReinsurancePremiums
2895	Implied Table	Table	*	*	implied:Table
2896	Disclosure of changes in balances of technical reserves for reinsurance premiums [Abstract]	Abstract			itub:DisclosureOfChangesInBalancesOfTechnicalReservesForReinsurancePremiumsAbstract
2897	Opening balance	Concept (Monetary)	As Of	Debit	itub:ReinsurancePremiums
2898	Receipts	Concept (Monetary)	For Period	Debit	itub:ReinsurancePremiumsReceipts
2899	Payments	Concept (Monetary)	For Period	Credit	itub:ReinsurancePremiumsPayments
2900	Other increase / reversal	Concept (Monetary)	For Period	Debit	itub:ReinsurancePremiumsOtherIncreaseOrReversal
2901	Closing balance	Concept (Monetary)	As Of	Debit	itub:ReinsurancePremiums
2902	1204 - Disclosure - Insurance Contracts - Summary of Changes in Balances of Technical Reserves for Reinsurance Commission (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureInsuranceContractsSummaryOfChangesInBalancesOfTechnicalReservesForReinsuranceCommission
2903	Implied Table	Table	*	*	implied:Table
2904	Disclosure of changes in balances of technical reserves for reinsurance commission [Abstract]	Abstract			itub:DisclosureOfChangesInBalancesOfTechnicalReservesForReinsuranceCommissionAbstract
2905	Opening balance	Concept (Monetary)	As Of	Debit	itub:ReinsuranceCommission
2906	Receipts	Concept (Monetary)	For Period	Debit	itub:ReinsuranceCommissionReceipts
2907	Payments	Concept (Monetary)	For Period	Credit	itub:ReinsuranceCommissionPayments
2908	Other increase / reversal	Concept (Monetary)	For Period	Debit	itub:ReinsuranceCommissionOtherIncreaseOrReversal
2909	Closing balance	Concept (Monetary)	As Of	Debit	itub:ReinsuranceCommission
2910	1205 - Disclosure - Fair Value of Financial Instruments - Summary of Carrying and Estimated Fair Values for Financial Instruments (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsSummaryOfCarryingAndEstimatedFairValuesForFinancialInstruments
2911	Disclosure of Fair Value Measurement of Assets and Liabilities [Table]	Table	*	*	itub:DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable
2912	Measurement [axis]	Axis			ifrs-full:MeasurementAxis
2913	Aggregated measurement [member]	Member			ifrs-full:AggregatedMeasurementMember
2914	Carrying value [Member]	Member			ifrs-full:NotMeasuredAtFairValueInStatementOfFinancialPositionButForWhichFairValueIsDisclosedMember
2915	Estimated fair value [Member]	Member			ifrs-full:AtFairValueMember
2916	Disclosure of fair value measurement of assets and liabilities [Line Items]	LineItems			itub:DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems
2917	Cash and deposits on demand and Central Bank compulsory deposits	Concept (Monetary)	As Of	Debit	itub:CashAndDepositsOnDemandAndCentralBankCompulsoryDeposits
2918	Interbank deposits	Concept (Monetary)	As Of	Debit	ifrs-full:ShorttermDepositsClassifiedAsCashEquivalents
2919	Securities purchased under agreements to resell	Concept (Monetary)	As Of	Debit	ifrs-full:ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed
2920	Financial assets held for trading	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
2921	Financial assets designated at fair value through profit or loss	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLoss
2922	Derivatives	Concept (Monetary)	As Of	Debit	ifrs-full:DerivativeFinancialAssets
2923	Available-for-sale financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAvailableforsale
2924	Held-to-maturity financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:HeldtomaturityInvestments
2925	Loan operations and lease operations	Concept (Monetary)	As Of	Debit	itub:LoanOperationsAndLeaseOperationsPortfolio
2926	Other financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:OtherFinancialAssets
2927	Deposits	Concept (Monetary)	As Of	Credit	ifrs-full:DepositsFromCustomers
2928	Securities sold under repurchase agreements	Concept (Monetary)	As Of	Credit	ifrs-full:RepurchaseAgreementsAndCashCollateralOnSecuritiesLent
2929	Financial liabilities held for trading	Concept (Monetary)	As Of	Credit	ifrs-full:FinancialLiabilitiesAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
2930	Derivatives	Concept (Monetary)	As Of	Credit	ifrs-full:DerivativeFinancialLiabilities
2931	Interbank market debt	Concept (Monetary)	As Of	Credit	itub:InterbankMarketDebt
2932	Institutional market debt	Concept (Monetary)	As Of	Credit	itub:InstitutionalMarketDebt
2933	Liabilities for capitalization plans	Concept (Monetary)	As Of	Credit	itub:LiabilitiesForCapitalizationPlans
2934	Other financial liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:OtherFinancialLiabilities
2935	1206 - Disclosure - Fair Value of Financial Instruments - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsAdditionalInformation
2936	Disclosure of Fair Value Measurement of Assets and Liabilities [Table]	Table	*	*	itub:DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesTable
2937	Measurement [axis]	Axis			ifrs-full:MeasurementAxis
2938	Aggregated measurement [member]	Member			ifrs-full:AggregatedMeasurementMember
2939	Estimated fair value [Member]	Member			ifrs-full:AtFairValueMember
2940	Range [axis]	Axis			ifrs-full:RangeAxis
2941	Ranges [member]	Member			ifrs-full:RangesMember
2942	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
2943	Top of range [member]	Member			ifrs-full:TopOfRangeMember
2944	Financial instruments measured at fair value through profit or loss because credit derivative is used to manage credit risk [axis]	Axis			ifrs-full:FinancialInstrumentsMeasuredAtFairValueThroughProfitOrLossBecauseCreditDerivativeIsUsedToManageCreditRiskAxis
2945	Financial instruments measured at fair value through profit or loss because credit derivative is used to manage credit risk [member]	Member			ifrs-full:FinancialInstrumentsMeasuredAtFairValueThroughProfitOrLossBecauseCreditDerivativeIsUsedToManageCreditRiskMember
2946	Scenarios I [Member]	Member			itub:ScenarioOneMember
2947	Scenarios II [Member]	Member			itub:ScenarioTwoMember
2948	Scenarios III [Member]	Member			itub:ScenarioThreeMember
2949	Types of risks [axis]	Axis			ifrs-full:TypesOfRisksAxis
2950	Risks [member]	Member			ifrs-full:TypesOfRisksMember
2951	Interest rates [Member]	Member			ifrs-full:InterestRateRiskMember
2952	Currency, commodities, and ratios [Member]	Member			ifrs-full:MarketRiskMember
2953	Nonlinear [Member]	Member			itub:NonlinearRiskMember
2954	Levels of fair value hierarchy [axis]	Axis			ifrs-full:LevelsOfFairValueHierarchyAxis
2955	All levels of fair value hierarchy [member]	Member			ifrs-full:AllLevelsOfFairValueHierarchyMember
2956	Level 2 [Member]	Member			ifrs-full:Level2OfFairValueHierarchyMember
2957	Disclosure of fair value measurement of assets and liabilities [Line Items]	LineItems			itub:DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems
2958	Standby letters of credit and financial guarantees	Concept (Monetary)	As Of	Credit	itub:StandbyLetterOfCreditAndLetterOfGuarantee
2959	Short-term assumption period	Concept (xbrli:durationItemType)	For Period		itub:ShorttermAssumptionPeriod
2960	Transfers out of Level 1 into Level 2 of fair value hierarchy, assets held at end of reporting period	Concept (Monetary)	For Period		ifrs-full:TransfersOutOfLevel1IntoLevel2OfFairValueHierarchyAssets
2961	Transfers out of Level 1 into Level 2 of fair value hierarchy, liabilities held at end of reporting period	Concept (Monetary)	For Period		ifrs-full:TransfersOutOfLevel1IntoLevel2OfFairValueHierarchyLiabilities
2962	Transfers out of Level 2 into Level 1 of fair value hierarchy, assets held at end of reporting period	Concept (Monetary)	For Period		ifrs-full:TransfersOutOfLevel2IntoLevel1OfFairValueHierarchyAssets
2963	Transfers out of Level 2 into Level 1 of fair value hierarchy, liabilities held at end of reporting period	Concept (Monetary)	For Period		ifrs-full:TransfersOutOfLevel2IntoLevel1OfFairValueHierarchyLiabilities
2964	Transfers into Level 3 of fair value hierarchy, assets	Concept (Monetary)	For Period	Debit	ifrs-full:TransfersIntoLevel3OfFairValueHierarchyAssets
2965	Transfers into Level 3 of fair value hierarchy, liabilities	Concept (Monetary)	For Period	Credit	ifrs-full:TransfersIntoLevel3OfFairValueHierarchyLiabilities
2966	Transfers out of Level 3 of fair value hierarchy, assets	Concept (Monetary)	For Period	Credit	ifrs-full:TransfersOutOfLevel3OfFairValueHierarchyAssets
2967	Transfers out of Level 3 of fair value hierarchy, liabilities	Concept (Monetary)	For Period	Debit	ifrs-full:TransfersOutOfLevel3OfFairValueHierarchyLiabilities
2968	Financial instruments classified as Level 2	Concept (Monetary)	As Of	Debit	itub:FinancialInstruments
2969	Fair vale of securities used to evaluate pricing service or brokers	Concept (Monetary)	As Of	Debit	itub:FairValueFinancialInstruments
2970	Purchase price of securities, percentage	Concept (Percent)	For Period		itub:PercentageOfPurchasePriceOfSecurities
2971	Shocks basis point	Concept (Percent)	For Period		itub:EstimatedSensitivityOnRiskFactorGroupsBasispointVariance
2972	1207 - Disclosure - Fair Value of Financial Instruments - Summary of Breakdown of Risk Levels for Financial Assets Held for Trading and Available-For-Sale Financial Assets (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsSummaryOfBreakdownOfRiskLevelsForFinancialAssetsHeldForTradingAndAvailableForSaleFinancialAssets
2973	Financial assets held for trading and available for sale financial assets [Table]	Table	*	*	itub:FinancialAssetsHeldForTradingAndAvailableForSaleFinancialAssetsTable
2974	Levels of fair value hierarchy [axis]	Axis			ifrs-full:LevelsOfFairValueHierarchyAxis
2975	All levels of fair value hierarchy [member]	Member			ifrs-full:AllLevelsOfFairValueHierarchyMember
2976	Level 1 [Member]	Member			ifrs-full:Level1OfFairValueHierarchyMember
2977	Level 2 [Member]	Member			ifrs-full:Level2OfFairValueHierarchyMember
2978	Level 3 [Member]	Member			ifrs-full:Level3OfFairValueHierarchyMember
2979	Unconsolidated structured entities [axis]	Axis			ifrs-full:UnconsolidatedStructuredEntitiesAxis
2980	Entity's total for unconsolidated structured entities [member]	Member			ifrs-full:EntitysTotalForUnconsolidatedStructuredEntitiesMember
2981	Investment funds [member]	Member			ifrs-full:InvestmentFundsMember
2982	Categories of financial assets [axis]	Axis			ifrs-full:CategoriesOfFinancialAssetsAxis
2983	Financial assets, category [member]	Member			ifrs-full:FinancialAssetsCategoryMember
2984	Brazilian government securities [Member]	Member			itub:BrazilianGovernmentSecuritiesMember
2985	Brazilian external debt bonds [Member]	Member			itub:BrazilianExternalDebtBondsMember
2986	Government securities - other countries [Member]	Member			itub:GovernmentSecuritiesMember
2987	Corporate securities [Member]	Member			itub:CorporateSecuritiesMember
2988	Geographical areas [axis]	Axis			ifrs-full:GeographicalAreasAxis
2989	Geographical areas [member]	Member			ifrs-full:GeographicalAreasMember
2990	Argentina [Member]	Member			country:AR
2991	Chile [Member]	Member			country:CL
2992	Colombia [Member]	Member			country:CO
2993	United States [Member]	Member			country:US
2994	Mexico [Member]	Member			country:MX
2995	Paraguay [Member]	Member			country:PY
2996	Uruguay [Member]	Member			country:UY
2997	Other [Member]	Member			itub:AllOtherCountriesMember
2998	Korea [Member]	Member			country:KR
2999	Denmark [Member]	Member			country:DK
3000	Spain [Member]	Member			country:ES
3001	FRANCE	Member			country:FR
3002	Netherlands [Member]	Member			country:NL
3003	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
3004	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
3005	Shares [Member]	Member			ifrs-full:EquityInvestmentsMember
3006	Bank deposit certificates [Member]	Member			itub:BankDepositCertificatesMember
3007	Securitized real estate loans [Member]	Member			itub:SecuritizedRealEstateLoansMember
3008	Debentures [Member]	Member			itub:DebenturesMember
3009	Eurobonds and others [Member]	Member			itub:EurobondsAndOthersMember
3010	Financial credit bills [Member]	Member			itub:FinancialCreditBillsMember
3011	Promissory notes [Member]	Member			itub:PromissoryNotesMember
3012	Other [Member]	Member			itub:OtherSecuritiesMember
3013	Rural Product Note [Member]	Member			itub:RuralProductNoteMember
3014	Categories of financial liabilities [axis]	Axis			ifrs-full:CategoriesOfFinancialLiabilitiesAxis
3015	Financial liabilities, category [member]	Member			ifrs-full:FinancialLiabilitiesCategoryMember
3016	Structured notes [Member]	Member			itub:StructuredNotesMember
3017	Financial assets held for trading and available for sale financial assets [Line Items]	LineItems			itub:FinancialAssetsHeldForTradingAndAvailableForSaleFinancialAssetsLineItems
3018	Financial assets held for trading	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
3019	Available-for-sale financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAvailableforsale
3020	Brazilian government securities	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLoss
3021	Financial liabilities held for trading	Concept (Monetary)	As Of	Credit	ifrs-full:FinancialLiabilitiesAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
3022	1208 - Disclosure - Fair Value of Financial Instruments - Summary of Breakdown of Risk Levels for Derivative Assets and Liabilities (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsSummaryOfBreakdownOfRiskLevelsForDerivativeAssetsAndLiabilities
3023	Disclosure Of Derivative Financial Instruments [Table]	Table	*	*	itub:DisclosureOfDerivativeFinancialInstrumentsTable
3024	Levels of fair value hierarchy [axis]	Axis			ifrs-full:LevelsOfFairValueHierarchyAxis
3025	All levels of fair value hierarchy [member]	Member			ifrs-full:AllLevelsOfFairValueHierarchyMember
3026	Level 1 [Member]	Member			ifrs-full:Level1OfFairValueHierarchyMember
3027	Level 2 [Member]	Member			ifrs-full:Level2OfFairValueHierarchyMember
3028	Level 3 [Member]	Member			ifrs-full:Level3OfFairValueHierarchyMember
3029	Classes of financial instruments [axis]	Axis			ifrs-full:ClassesOfFinancialInstrumentsAxis
3030	Financial instruments, class [member]	Member			ifrs-full:ClassesOfFinancialInstrumentsMember
3031	Futures [Member]	Member			ifrs-full:FuturesContractMember
3032	Swap [Member]	Member			ifrs-full:SwapContractMember
3033	Options [Member]	Member			itub:CurrencyOptionsContractMember
3034	Forwards (onshore) [Member]	Member			itub:ForwardsOnshoreContractMember
3035	Credit derivatives [Member]	Member			itub:CreditDerivativesMember
3036	Forwards (offshore) Contract [Member]	Member			itub:ForwardsOffshoreContractMember
3037	Check of swap [Member]	Member			itub:CheckOfSwapMember
3038	Other derivatives [Member]	Member			itub:OtherDerivativesMember
3039	Disclosure Of Derivative Financial Instruments [Line Items]	LineItems			itub:DisclosureOfDerivativeFinancialInstrumentsLineItems
3040	Derivatives - assets	Concept (Monetary)	As Of	Debit	ifrs-full:DerivativeFinancialAssets
3041	Derivatives - liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:DerivativeFinancialLiabilities
3042	1209 - Disclosure - Fair Value of Financial Instruments - Summary of Changes in Balance Sheet for Financial Instruments Classified by Level 3 Fair Value Hierarchy (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsSummaryOfChangesInBalanceSheetForFinancialInstrumentsClassifiedByLevel3FairValueHierarchy
3043	Disclosure of Fair Value Gains and Losses of Derivative Financial Instruments [Table]	Table	*	*	itub:DisclosureOfFairValueGainsAndLossesOfDerivativeFinancialInstrumentsTable
3044	Levels of fair value hierarchy [axis]	Axis			ifrs-full:LevelsOfFairValueHierarchyAxis
3045	All levels of fair value hierarchy [member]	Member			ifrs-full:AllLevelsOfFairValueHierarchyMember
3046	Level 3 [Member]	Member			ifrs-full:Level3OfFairValueHierarchyMember
3047	Categories of financial assets [axis]	Axis			ifrs-full:CategoriesOfFinancialAssetsAxis
3048	Financial assets, category [member]	Member			ifrs-full:FinancialAssetsCategoryMember
3049	Brazilian government securities [Member]	Member			itub:BrazilianGovernmentSecuritiesMember
3050	Corporate securities [Member]	Member			itub:CorporateSecuritiesMember
3051	Government securities - other countries [Member]	Member			itub:GovernmentSecuritiesMember
3052	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
3053	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
3054	Shares [Member]	Member			ifrs-full:EquityInvestmentsMember
3055	Securitized real estate loans [Member]	Member			itub:SecuritizedRealEstateLoansMember
3056	Debentures [Member]	Member			itub:DebenturesMember
3057	Eurobonds and others [Member]	Member			itub:EurobondsAndOthersMember
3058	Financial credit bills [Member]	Member			itub:FinancialCreditBillsMember
3059	Other [Member]	Member			itub:OtherSecuritiesMember
3060	Rural Product Note [Member]	Member			itub:RuralProductNoteMember
3061	Bank deposit certificates [Member]	Member			itub:BankDepositCertificatesMember
3062	Swap [Member]	Member			ifrs-full:SwapContractMember
3063	Options [Member]	Member			itub:CurrencyOptionsContractMember
3064	Credit derivatives [Member]	Member			itub:CreditDerivativesMember
3065	Other derivatives [Member]	Member			itub:OtherDerivativesMember
3066	Promissory notes [Member]	Member			itub:PromissoryNotesMember
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3068	Geographical areas [member]	Member			ifrs-full:GeographicalAreasMember
3069	Chile [Member]	Member			country:CL
3070	Unconsolidated structured entities [axis]	Axis			ifrs-full:UnconsolidatedStructuredEntitiesAxis
3071	Entity's total for unconsolidated structured entities [member]	Member			ifrs-full:EntitysTotalForUnconsolidatedStructuredEntitiesMember
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3073	Disclosure Of Fair Value Gains And Losses Of Derivative Financial Instruments [Line Items]	LineItems			itub:DisclosureOfFairValueGainsAndLossesOfDerivativeFinancialInstrumentsLineItems
3074	Fair value, Beginning balance	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
3075	Total gains or losses (realized / unrealized)	Concept (Monetary)	For Period	Credit	itub:RealizedOrUnrealizedGainsLossesOnFinancialAssetsHeldForTrading
3076	Purchases	Concept (Monetary)	For Period	Credit	itub:PurchaseOfHeldToMaturityFinancialAssets
3077	Settlements	Concept (Monetary)	For Period	Credit	itub:SettlementsFairValueMeasurementAssetsHeldForTrading
3078	Transfers in and / or out of Level 3	Concept (Monetary)	For Period	Debit	itub:TransfersIntoLevelOfFairValueHierarchyAssetsHeldForTrading
3079	Fair value, Ending balance	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
3080	Total gains (losses) related to assets and liabilities	Concept (Monetary)	For Period	Credit	ifrs-full:GainsLossesOnFinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
3081	Fair value, Beginning balance	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAvailableforsale
3082	Total gains or losses (realized / unrealized)	Concept (Monetary)	For Period	Credit	itub:RealizedOrUnrealizedGainsLossesOnFinancialAssetsAvailableForSale
3083	Purchases	Concept (Monetary)	For Period	Credit	ifrs-full:PurchaseOfAvailableforsaleFinancialAssets
3084	Settlements	Concept (Monetary)	For Period	Credit	ifrs-full:SettlementsFairValueMeasurementAssets
3085	Transfers in and / or out of Level 3	Concept (Monetary)	For Period	Debit	ifrs-full:TransfersIntoLevel3OfFairValueHierarchyAssets
3086	Fair value, Ending balance	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAvailableforsale
3087	Total gains (losses) related to assets and liabilities	Concept (Monetary)	For Period	Credit	ifrs-full:GainsLossesOnAvailableforsaleFinancialAssets
3088	Fair value, Beginning balance	Concept (Monetary)	As Of	Debit	ifrs-full:DerivativeFinancialAssets
3089	Total gains or losses (realized / unrealized)	Concept (Monetary)	For Period	Debit	itub:RealizedOrUnrealizedGainsLossesOnDerivativeAssets
3090	Purchases	Concept (Monetary)	For Period	Credit	itub:PurchaseOfDerivativeAssets
3091	Settlements	Concept (Monetary)	For Period	Credit	itub:SettlementsOfDerivativeAssets
3092	Transfers in and / or out of Level 3	Concept (Monetary)	For Period	Debit	itub:TransfersIntoLevelOfFairValueHierarchyDerivativeAssets
3093	Fair value, Ending balance	Concept (Monetary)	As Of	Debit	ifrs-full:DerivativeFinancialAssets
3094	Total gains (losses) related to assets and liabilities	Concept (Monetary)	For Period	Credit	itub:GainsLossesOnDerivativeAssets
3095	Fair value, Beginning balance	Concept (Monetary)	As Of	Credit	ifrs-full:DerivativeFinancialLiabilities
3096	Total gains or losses (realized / unrealized)	Concept (Monetary)	For Period	Debit	itub:RealizedOrUnrealizedGainsLossesOnDerivativeLiabilities
3097	Purchases	Concept (Monetary)	For Period	Credit	itub:PurchaseOfDerivativeLiabilities
3098	Settlements	Concept (Monetary)	For Period	Credit	itub:SettlementsOfDerivativeLiabilities
3099	Transfers in and / or out of Level 3	Concept (Monetary)	For Period	Debit	itub:TransfersIntoLevelOfFairValueHierarchyDerivativeLiabilities
3100	Fair value, Ending balance	Concept (Monetary)	As Of	Credit	ifrs-full:DerivativeFinancialLiabilities
3101	Total gains (losses) related to assets and liabilities	Concept (Monetary)	For Period	Credit	itub:GainsLossesOnDerivativeLiabilities
3102	1210 - Disclosure - Fair Value of Financial Instruments - Summary of Sensitivity Analyses Operations of Level 3 (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsSummaryOfSensitivityAnalysesOperationsOfLevel3
3103	Disclosure of Fair Value Financial Sensitivity Analysis [Table]	Table	*	*	itub:DisclosureOfFairValueFinancialSensitivityAnalysisTable
3104	Types of risks [axis]	Axis			ifrs-full:TypesOfRisksAxis
3105	Risks [member]	Member			ifrs-full:TypesOfRisksMember
3106	Interest rates [Member]	Member			ifrs-full:InterestRateRiskMember
3107	Currency, commodities, and ratios [Member]	Member			ifrs-full:MarketRiskMember
3108	Nonlinear [Member]	Member			itub:NonlinearRiskMember
3109	Financial instruments measured at fair value through profit or loss because credit derivative is used to manage credit risk [axis]	Axis			ifrs-full:FinancialInstrumentsMeasuredAtFairValueThroughProfitOrLossBecauseCreditDerivativeIsUsedToManageCreditRiskAxis
3110	Financial instruments measured at fair value through profit or loss because credit derivative is used to manage credit risk [member]	Member			ifrs-full:FinancialInstrumentsMeasuredAtFairValueThroughProfitOrLossBecauseCreditDerivativeIsUsedToManageCreditRiskMember
3111	Scenarios I [Member]	Member			itub:ScenarioOneMember
3112	Scenarios II [Member]	Member			itub:ScenarioTwoMember
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3114	Disclosure of Fair Value Financial Sensitivity Analysis [Line Items]	LineItems			itub:DisclosureOfFairValueFinancialSensitivityAnalysisLineItems
3115	Impact, Result	Concept (Monetary)	As Of	Debit	itub:SensitivityAnalysisImpactOnAssetFairValue
3116	Impact, Stockholders' equity	Concept (Monetary)	As Of	Credit	itub:SensitivityAnalysisImpactOnStockholderEquity
3117	1211 - Disclosure - Provisions, Contingencies and Other Commitments - Summary of Provision (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureProvisionsContingenciesAndOtherCommitmentsSummaryOfProvision
3118	Disclosure of Provisions [Table]	Table	*	*	itub:DisclosureOfProvisionsTable
3119	Classes of other provisions [axis]	Axis			ifrs-full:ClassesOfProvisionsAxis
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3121	Legal proceedings provision [member]	Member			ifrs-full:LegalProceedingsProvisionMember
3122	Labor [Member]	Member			itub:LaborProvisionMember
3123	Provision for taxes other than income tax [member]	Member			ifrs-full:ProvisionForTaxesOtherThanIncomeTaxMember
3124	Other [Member]	Member			ifrs-full:MiscellaneousOtherProvisionsMember
3125	Disclosure of Provisions [Line Items]	LineItems			itub:DisclosureOfProvisionsLineItems
3126	Provision	Concept (Monetary)	As Of	Credit	ifrs-full:Provisions
3127	Current	Concept (Monetary)	As Of	Credit	ifrs-full:CurrentProvisions
3128	Non-current	Concept (Monetary)	As Of	Credit	ifrs-full:NoncurrentProvisions
3129	1212 - Disclosure - Provisions, Contingencies and Other Commitments - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureProvisionsContingenciesAndOtherCommitmentsAdditionalInformation
3130	Disclosure of Provisions [Table]	Table	*	*	itub:DisclosureOfProvisionsTable
3131	Classes of other provisions [axis]	Axis			ifrs-full:ClassesOfProvisionsAxis
3132	Other provisions [member]	Member			ifrs-full:OtherProvisionsMember
3133	Labor claims [Member]	Member			itub:LaborClaimsMember
3134	Civil lawsuits [Member]	Member			itub:CivilLawsuitsMember
3135	Categories of related parties [axis]	Axis			ifrs-full:CategoriesOfRelatedPartiesAxis
3136	Entity's total for related parties [member]	Member			ifrs-full:EntitysTotalForRelatedPartiesMember
3137	ISS [Member]	Member			itub:ISSMember
3138	CSLL [Member]	Member			itub:CSLLMember
3139	PIS and COFINS [Member]	Member			itub:PisAndCofinsMember
3140	INSS [Member]	Member			itub:INSSMember
3141	IRPJ and CSLL [Member]	Member			itub:IrpjandcsllMember
3142	IRPJ [Member]	Member			itub:IRPJMember
3143	Range [axis]	Axis			ifrs-full:RangeAxis
3144	Ranges [member]	Member			ifrs-full:RangesMember
3145	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
3146	Top of range [member]	Member			ifrs-full:TopOfRangeMember
3147	Disclosure of Provisions [Line Items]	LineItems			itub:DisclosureOfProvisionsLineItems
3148	Provisions	Concept (Monetary)	As Of	Credit	ifrs-full:Provisions
3149	Total estimated risk	Concept (Monetary)	As Of	Debit	itub:LossContingencyValue1
3150	Provisions recognized for tax and social securities lawsuits	Concept (Monetary)	For Period	Debit	itub:ProvisionForTaxAndSocialSecurityLawsuits
3151	CSLL rate for financial and insurance companies	Concept (Percent)	For Period		itub:CSLLRatePercentage
3152	Deposit balance	Concept (Monetary)	As Of	Debit	itub:EscrowDeposit1
3153	Estimated amounts at risk in main tax and social security lawsuits	Concept (Monetary)	As Of	Credit	itub:EstimatedAmountsAtRiskInMainTaxAndSocialSecurityLawsuits
3154	Non-compensatory amounts	Concept (Monetary)	For Period	Debit	itub:NoncompensatoryAmounts
3155	Goodwill - Deduction	Concept (Monetary)	For Period	Debit	ifrs-full:ChangesInGoodwill
3156	Reversal of revenues from depreciation in excess	Concept (Monetary)	For Period	Debit	itub:ReversalOfRevenuesFromDepreciationInExcess
3157	Goodwill amount guaranteed in purchase agreements	Concept (Monetary)	For Period	Debit	ifrs-full:AdditionalRecognitionGoodwill
3158	Interest on capital	Concept (Monetary)	For Period	Debit	itub:InterestOnCapital
3159	Amounts related to banking operation	Concept (Monetary)	For Period	Credit	ifrs-full:RevenueFromRenderingOfServices
3160	Deductibility of losses in credit operations	Concept (Monetary)	As Of	Credit	ifrs-full:AllowanceAccountForCreditLossesOfFinancialAssets
3161	Receivables balance arising from reimbursements of contingencies	Concept (Monetary)	For Period	Credit	itub:IncomeFromReimbursementsUnderContingencies
3162	1213 - Disclosure - Provisions, Contingencies and Other Commitments - Summary of Changes in the Balances of Provisions for Civil, Labor and Other Provision and Escrow Deposit Balances (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureProvisionsContingenciesAndOtherCommitmentsSummaryOfChangesInTheBalancesOfProvisionsForCivilLaborAndOtherProvisionAndEscrowDepositBalances
3163	Disclosure of other provisions [table]	Table	*	*	ifrs-full:DisclosureOfOtherProvisionsTable
3164	Classes of other provisions [axis]	Axis			ifrs-full:ClassesOfProvisionsAxis
3165	Other provisions [member]	Member			ifrs-full:OtherProvisionsMember
3166	Legal proceedings provision [member]	Member			ifrs-full:LegalProceedingsProvisionMember
3167	Labor [Member]	Member			itub:LaborProvisionMember
3168	Other [Member]	Member			ifrs-full:MiscellaneousOtherProvisionsMember
3169	Civil labor and other provisions [member]	Member			itub:CivilLaborAndOtherProvisionsMember
3170	Business combinations [axis]	Axis			ifrs-full:BusinessCombinationsAxis
3171	Entity's total for business combinations [member]	Member			ifrs-full:EntitysTotalForBusinessCombinationsMember
3172	Corp Banca [Member]	Member			itub:CorpBancaMember
3173	Citibank [Member]	Member			itub:CitibankMember
3174	Disclosure of other provisions [line items]	LineItems			ifrs-full:DisclosureOfOtherProvisionsLineItems
3175	Opening balance	Concept (Monetary)	As Of	Credit	ifrs-full:Provisions
3176	Balance arising from Corpbanca acquisition	Concept (Monetary)	For Period	Credit	ifrs-full:AcquisitionsThroughBusinessCombinationsOtherProvisions
3177	(-) Contingencies guaranteed by indemnity clause	Concept (Monetary)	For Period	Credit	itub:DecreaseInContingenciesGuaranteedByIndemnityClause
3178	Subtotal	Concept (Monetary)	For Period	Credit	itub:ProvisionsDuringThePeriod
3179	Interest	Concept (Monetary)	For Period	Credit	itub:InterestOnProvisions
3180	Changes in the period reflected in results	Concept (Monetary)	For Period	Credit	ifrs-full:AdditionalProvisionsOtherProvisions
3181	Increase	Concept (Monetary)	For Period	Credit	ifrs-full:NewProvisionsOtherProvisions
3182	Reversal	Concept (Monetary)	For Period	Credit	ifrs-full:IncreaseDecreaseInExistingProvisionsOtherProvisions
3183	Payment	Concept (Monetary)	For Period	Debit	ifrs-full:ProvisionUsedOtherProvisions
3184	Subtotal	Concept (Monetary)	For Period	Credit	ifrs-full:ChangesInOtherProvisions
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3186	Closing balance	Concept (Monetary)	As Of	Credit	ifrs-full:Provisions
3187	Escrow deposits	Concept (Monetary)	As Of	Debit	itub:EscrowDeposit1
3188	1214 - Disclosure - Provisions, Contingencies and Other Commitments - Summary of Changes in the Balances of Provisions for Civil, Labor and Other Provision and Escrow Deposit Balances (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureProvisionsContingenciesAndOtherCommitmentsSummaryOfChangesInTheBalancesOfProvisionsForCivilLaborAndOtherProvisionAndEscrowDepositBalancesParenthetical
3189	Disclosure of other provisions [table]	Table	*	*	ifrs-full:DisclosureOfOtherProvisionsTable
3190	Classes of other provisions [axis]	Axis			ifrs-full:ClassesOfProvisionsAxis
3191	Other provisions [member]	Member			ifrs-full:OtherProvisionsMember
3192	Economic Plans [member]	Member			itub:EconomicPlansMember
3193	Disclosure of other provisions [line items]	LineItems			ifrs-full:DisclosureOfOtherProvisionsLineItems
3194	Increase in provision	Concept (Monetary)	For Period	Credit	ifrs-full:NewProvisionsOtherProvisions
3195	1215 - Disclosure - Provisions, Contingencies and Other Commitments - Summary of Changes in Balances of Provisions and Respective Balance of Escrow Deposits for Tax and Social Security Lawsuits (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureProvisionsContingenciesAndOtherCommitmentsSummaryOfChangesInBalancesOfProvisionsAndRespectiveBalanceOfEscrowDepositsForTaxAndSocialSecurityLawsuits
3196	Disclosure of other provisions [table]	Table	*	*	ifrs-full:DisclosureOfOtherProvisionsTable
3197	Classes of other provisions [axis]	Axis			ifrs-full:ClassesOfProvisionsAxis
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3199	Provision for taxes other than income tax [member]	Member			ifrs-full:ProvisionForTaxesOtherThanIncomeTaxMember
3200	Disclosure of other provisions [line items]	LineItems			ifrs-full:DisclosureOfOtherProvisionsLineItems
3201	Opening balance	Concept (Monetary)	As Of	Credit	ifrs-full:Provisions
3202	(-) Contingencies guaranteed by indemnity clause	Concept (Monetary)	For Period	Credit	itub:DecreaseInContingenciesGuaranteedByIndemnityClause
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3206	Increase	Concept (Monetary)	For Period	Credit	ifrs-full:NewProvisionsOtherProvisions
3207	Reversal	Concept (Monetary)	For Period	Credit	ifrs-full:IncreaseDecreaseInExistingProvisionsOtherProvisions
3208	Payment	Concept (Monetary)	For Period	Debit	ifrs-full:ProvisionUsedOtherProvisions
3209	Subtotal	Concept (Monetary)	For Period	Credit	ifrs-full:ChangesInOtherProvisions
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3211	Closing balance	Concept (Monetary)	As Of	Credit	ifrs-full:Provisions
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3217	Deposits released	Concept (Monetary)	For Period	Credit	itub:DepositsReleased
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3221	1216 - Disclosure - Provisions, Contingencies and Other Commitments - Summary of Assets Pledged as Collateral for Lawsuits Involving Contingent Liabilities are Restricted or Deposited (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureProvisionsContingenciesAndOtherCommitmentsSummaryOfAssetsPledgedAsCollateralForLawsuitsInvolvingContingentLiabilitiesAreRestrictedOrDeposited
3222	Disclosure of contingent liabilities [table]	Table	*	*	ifrs-full:DisclosureOfContingentLiabilitiesTable
3223	Items of contingent liabilities [axis]	Axis			ifrs-full:ItemsOfContingentLiabilitiesAxis
3224	Items of contingent liabilities [member]	Member			ifrs-full:ItemsOfContingentLiabilitiesMember
3225	Assets Pledged As Collateral For Liabilities Or Contingent Liabilities [Member]	Member			itub:AssetsPledgedAsCollateralForLiabilitiesOrContingentLiabilitiesMember
3226	Disclosure of contingent liabilities [line items]	LineItems			ifrs-full:DisclosureOfContingentLiabilitiesLineItems
3227	Financial assets held for trading and Available-for-sale financial assets (basically financial treasury bills)	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAvailableforsale
3228	Escrow deposits	Concept (Monetary)	As Of	Debit	itub:EscrowDeposit1
3229	1217 - Disclosure - Regulatory Capital - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureRegulatoryCapitalAdditionalInformation
3230	Disclosure of regulatory capital [Table]	Table	*	*	itub:DisclosureOfRegulatoryCapitalTable
3231	Non-adjusting events after reporting period [axis]	Axis			ifrs-full:NonadjustingEventsAfterReportingPeriodAxis
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3233	Events After Reporting Period [Member]	Member			itub:EventsAfterReportingPeriodMember
3234	Range [axis]	Axis			ifrs-full:RangeAxis
3235	Ranges [member]	Member			ifrs-full:RangesMember
3236	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
3237	Borrowings by name [axis]	Axis			ifrs-full:BorrowingsByNameAxis
3238	Borrowings by name [member]	Member			ifrs-full:BorrowingsByNameMember
3239	Six point one two five percentage perpetual subordinated notes [member]	Member			itub:SixPointOneTwoFivePercentagePerpetualSubordinatedNotesMember
3240	Types of risks [axis]	Axis			ifrs-full:TypesOfRisksAxis
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3242	RWAMINT [Member]	Member			itub:RWAMINTMember
3243	RWAMPAD [Member]	Member			itub:RWAMPADMember
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3257	1218 - Disclosure - Regulatory Capital - Summary of Implementation of Basel III Rules (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureRegulatoryCapitalSummaryOfImplementationOfBaselIIIRules
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3273	1219 - Disclosure - Regulatory Capital - Summary of Composition of the Referential Equity (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureRegulatoryCapitalSummaryOfCompositionOfTheReferentialEquity
3274	Disclosure of regulatory capital [Table]	Table	*	*	itub:DisclosureOfRegulatoryCapitalTable
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3305	1221 - Disclosure - Regulatory Capital - Summary of Funds Obtained Through the Issuance of Subordinated Debt Securities (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureRegulatoryCapitalSummaryOfFundsObtainedThroughTheIssuanceOfSubordinatedDebtSecurities
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3341	1222 - Disclosure - Regulatory Capital - Summary of Funds Obtained Through the Issuance of Subordinated Debt Securities (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureRegulatoryCapitalSummaryOfFundsObtainedThroughTheIssuanceOfSubordinatedDebtSecuritiesParenthetical
3342	Disclosure of regulatory capital [Table]	Table	*	*	itub:DisclosureOfRegulatoryCapitalTable
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3373	Disclosure of credit risk exposure [table]	Table	*	*	ifrs-full:DisclosureOfCreditRiskExposureTable
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3406	Disclosure of credit risk exposure [table]	Table	*	*	ifrs-full:DisclosureOfCreditRiskExposureTable
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3419	Disclosure of credit risk exposure [line items]	LineItems			ifrs-full:DisclosureOfCreditRiskExposureLineItems
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3421	1225 - Disclosure - Regulatory Capital - Summary of Risk-Weighted Assets of Market Risk (RWAMINT) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureRegulatoryCapitalSummaryOfRiskWeightedAssetsOfMarketRiskRWAMINT
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3437	Fixed rate denominated in Real	Concept (Monetary)	As Of	Debit	itub:OperationsSubjectToInterestRateVariations
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3460	1228 - Disclosure - Regulatory Capital - Disclosure of Capital Adequacy (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureRegulatoryCapitalDisclosureOfCapitalAdequacy
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3473	1229 - Disclosure - Regulatory Capital - Disclosure of Basel and Fixed Asset Ratios (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureRegulatoryCapitalDisclosureOfBaselAndFixedAssetRatios
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3483	1230 - Disclosure - Segment Information - Summary of Operating Segments (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureSegmentInformationSummaryOfOperatingSegments
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3486	Segments [member]	Member			ifrs-full:SegmentsMember
3487	Retail Banking [Member]	Member			itub:RetailBankingMember
3488	Wholesale Banking [member]	Member			itub:WholesaleBankingMember
3489	Market And Corporation [Member]	Member			itub:MarketAndCorporationMember
3490	Ita Unibanco SA [Member]	Member			itub:ItaUnibancoSaMember
3491	Adjustments [Member]	Member			itub:AdjustmentsMember
3492	Disclosure of operating segments [line items]	LineItems			ifrs-full:DisclosureOfOperatingSegmentsLineItems
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3494	Total liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:Liabilities
3495	Investments in associates and joint ventures	Concept (Monetary)	As Of	Debit	itub:InvestmentsInJointVenturesAndAssociates
3496	Goodwill	Concept (Monetary)	As Of	Debit	ifrs-full:Goodwill
3497	Fixed assets, net	Concept (Monetary)	As Of	Debit	ifrs-full:PropertyPlantAndEquipment
3498	Intangible assets, net	Concept (Monetary)	As Of	Debit	ifrs-full:IntangibleAssetsOtherThanGoodwill
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3500	Interest margin (	Concept (Monetary)	For Period	Credit	itub:NetInterestIncome
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3502	Income related to insurance, private pension, and capitalization operations before claim and selling expenses	Concept (Monetary)	For Period	Credit	itub:IncomeRelatedToInsurancePrivatePensionAndCapitalizationOperationsBeforeClaimAndSellingExpenses
3503	Other income	Concept (Monetary)	For Period	Credit	ifrs-full:OtherIncome
3504	Losses on loans and claims	Concept (Monetary)	For Period	Debit	ifrs-full:IncreaseDecreaseInInsuranceLiabilitiesNetOfReinsurance
3505	Expenses for allowance for loan and lease losses	Concept (Monetary)	For Period	Debit	ifrs-full:ClaimsAndBenefitsPaidNetOfReinsuranceRecoveries
3506	Impairment	Concept (Monetary)	For Period	Debit	ifrs-full:ImpairmentLoss
3507	Discounts granted	Concept (Monetary)	For Period	Debit	itub:DiscountsGranted
3508	Recovery of loans written off as loss	Concept (Monetary)	For Period	Credit	ifrs-full:PremiumsWrittenNetOfReinsurance
3509	Expenses for claims / recovery of claims under reinsurance	Concept (Monetary)	For Period	Debit	itub:ExpensesRecoveryForClaimsUnderReinsurance
3510	Operating margin	Concept (Monetary)	For Period	Credit	itub:BankingProductNetOfLossesOnLoansAndClaims
3511	Other operating income (expenses)	Concept (Monetary)	For Period	Credit	itub:MiscellaneousOtherOperatingIncomeExpense
3512	Non-interest expenses	Concept (Monetary)	For Period	Debit	itub:NonInterestExpense1
3513	Tax expenses for ISS, PIS and COFINS and Other	Concept (Monetary)	For Period	Debit	ifrs-full:TaxExpenseOtherThanIncomeTaxExpense
3514	Share of profit or (loss) in associates and joint ventures	Concept (Monetary)	For Period	Credit	ifrs-full:ShareOfProfitLossOfAssociatesAndJointVenturesAccountedForUsingEquityMethod
3515	Income before income tax and social contribution	Concept (Monetary)	For Period	Credit	itub:ProfitLossBeforeTaxAndSocialContribution
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3517	Non-controlling interest in subsidiaries	Concept (Monetary)	For Period	Credit	ifrs-full:ProfitLossAttributableToNoncontrollingInterests
3518	Result of Citibank's operations	Concept (Monetary)	For Period	Credit	ifrs-full:ProfitLossOfAcquiree
3519	Net income	Concept (Monetary)	For Period	Credit	ifrs-full:ProfitLossAttributableToOwnersOfParent
3520	1231 - Disclosure - Segment Information - Summary of Operating Segments (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureSegmentInformationSummaryOfOperatingSegmentsParenthetical
3521	Implied Table	Table	*	*	implied:Table
3522	Disclosure of operating segments [abstract]	Abstract			ifrs-full:DisclosureOfOperatingSegmentsAbstract
3523	Interest and similar income and expenses	Concept (Monetary)	For Period	Credit	itub:InterestAndSimilarIncomeExpense
3524	Dividend income	Concept (Monetary)	For Period	Credit	ifrs-full:AdjustmentsForDividendIncome
3525	Net gains (loss) on investment securities and derivatives	Concept (Monetary)	For Period	Credit	itub:NetGainLossOnInvestmentSecuritiesAndDerivatives
3526	Results from foreign exchange operation	Concept (Monetary)	For Period	Credit	itub:AdjustmentsForForeignExchangeGainsLosses
3527	Depreciation expense	Concept (Monetary)	For Period	Debit	ifrs-full:DepreciationExpense
3528	Amortisation expense	Concept (Monetary)	For Period	Debit	ifrs-full:AmortisationExpense
3529	Insurance acquisition expenses	Concept (Monetary)	For Period	Debit	itub:InsuranceAcquisitionExpense
3530	Insurance acquisition expenses	Concept (Monetary)	For Period	Debit	ifrs-full:InsuranceExpense
3531	1232 - Disclosure - Segment Information - Summary of Information on Result of Main Services and Products and Noncurrent Assets by Geographic Area (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureSegmentInformationSummaryOfInformationOnResultOfMainServicesAndProductsAndNoncurrentAssetsByGeographicArea
3532	Disclosure of geographical areas [table]	Table	*	*	ifrs-full:DisclosureOfGeographicalAreasTable
3533	Geographical areas [axis]	Axis			ifrs-full:GeographicalAreasAxis
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3535	Brazil [Member]	Member			country:BR
3536	Abroad [Member]	Member			itub:AbroadMember
3537	Disclosure of geographical areas [line items]	LineItems			ifrs-full:DisclosureOfGeographicalAreasLineItems
3538	Income related to financial operations	Concept (Monetary)	For Period	Debit	itub:IncomeFromFinancialOperations
3539	Income related to insurance, private pension and capitalization operations before claim and selling expenses	Concept (Monetary)	For Period	Credit	itub:IncomeRelatedToInsurancePrivatePensionAndCapitalizationOperationsBeforeClaimAndSellingExpenses
3540	Banking service fees	Concept (Monetary)	For Period	Credit	itub:BankingServiceFees
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3542	1233 - Disclosure - Segment Information - Summary of Information on Result of Main Services and Products and Noncurrent Assets by Geographic Area (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureSegmentInformationSummaryOfInformationOnResultOfMainServicesAndProductsAndNoncurrentAssetsByGeographicAreaParenthetical
3543	Implied Table	Table	*	*	implied:Table
3544	Disclosure of geographical areas [abstract]	Abstract			ifrs-full:DisclosureOfGeographicalAreasAbstract
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3546	1234 - Disclosure - Related Parties - Summary of Transactions Between Related Parties (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureRelatedPartiesSummaryOfTransactionsBetweenRelatedParties
3547	Disclosure of transactions between related parties [table]	Table	*	*	ifrs-full:DisclosureOfTransactionsBetweenRelatedPartiesTable
3548	Assets and liabilities [axis]	Axis			ifrs-full:AssetsAndLiabilitiesAxis
3549	Assets and liabilities [member]	Member			ifrs-full:AssetsAndLiabilitiesMember
3550	Loan Operations [Member]	Member			itub:LoanOperationsMember
3551	Securities sold under repurchase agreements [Member]	Member			itub:SecuritiesSoldUnderRepurchaseAgreementsMember
3552	Amounts Receivable from payable to related companies banking service fees expenses [Member]	Member			itub:AmountsReceivableFromPayableToRelatedCompaniesBankingServiceFeesExpensesMember
3553	Rental revenues expenses [Member]	Member			itub:RentalRevenuesExpensesMember
3554	Donation expenses [Member]	Member			itub:DonationExpensesMember
3555	Categories of related parties [axis]	Axis			ifrs-full:CategoriesOfRelatedPartiesAxis
3556	Entity's total for related parties [member]	Member			ifrs-full:EntitysTotalForRelatedPartiesMember
3557	Alpargatas SA [Member]	Member			itub:AlpargatasSAMember
3558	Duratex S.A. [Member]	Member			itub:DuratexSAMember
3559	Elekeiroz S.A. [Member]	Member			itub:ElekeirozSAMember
3560	ItautecS A Member	Member			itub:ItautecSAMember
3561	Itausa Empreendimentos S.A. [Member]	Member			itub:ItausaEmpreendimentosSAMember
3562	Olimpia Promocao e Servicos S.A. [Member]	Member			itub:OlimpiaPromocaoEServicosSAMember
3563	Conectcar Solucoes de Mobilidade Eletronica S.A. [Member]	Member			itub:ConectCarSolucoesDeMobilidadeEletronicaSAMember
3564	Other [Member]	Member			itub:OtherMember
3565	Itausa Investimentos Itau S.A. [Member]	Member			itub:ItausaInvestimentosItauSAMember
3566	Fundacao Itau Unibanco Previdencia Complementar [Member]	Member			itub:FundacaoItauUnibancoPrevidenciaComplementarMember
3567	Funbep Fundo De Pensao Multipatrocinado [Member]	Member			itub:FunbepFundoDePensaoMultipatrocinadoMember
3568	Instituto Itau Cultural [Member]	Member			itub:InstitutoItauCulturalMember
3569	Associacao Cubo Coworking Itau [Member]	Member			itub:AssociacaoCuboCoworkingItauMember
3570	Associacao Itau Viver Mais [Member]	Member			itub:AssociacaoItauViverMaisMember
3571	Disclosure of transactions between related parties [line items]	LineItems			ifrs-full:DisclosureOfTransactionsBetweenRelatedPartiesLineItems
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3575	1235 - Disclosure - Related Parties - Summary of Transactions Between Related Parties (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureRelatedPartiesSummaryOfTransactionsBetweenRelatedPartiesParenthetical
3576	Disclosure of transactions between related parties [table]	Table	*	*	ifrs-full:DisclosureOfTransactionsBetweenRelatedPartiesTable
3577	Range [axis]	Axis			ifrs-full:RangeAxis
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3579	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
3580	Disclosure of transactions between related parties [line items]	LineItems			ifrs-full:DisclosureOfTransactionsBetweenRelatedPartiesLineItems
3581	Percentage of capital stock holds by bank directly or indirectly	Concept (Percent)	For Period		itub:PercentageOfCapitalStockHoldsByBankDirectlyOrIndirectly
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3583	Disclosure of transactions between related parties [table]	Table	*	*	ifrs-full:DisclosureOfTransactionsBetweenRelatedPartiesTable
3584	Types of share-based payment arrangements [axis]	Axis			ifrs-full:TypesOfSharebasedPaymentArrangementsAxis
3585	Share-based payment arrangements [member]	Member			ifrs-full:SharebasedPaymentArrangementsMember
3586	Compensation [Member]	Member			itub:CompensationMember
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3588	Contribution To Pension Plans [Member]	Member			itub:ContributionToPensionPlansMember
3589	Stock Option Plan [member]	Member			itub:StockOptionPlanMember
3590	Separate management entities [axis]	Axis			ifrs-full:SeparateManagementEntitiesAxis
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3593	Executives [Member]	Member			itub:ExecutivesMember
3594	Disclosure of transactions between related parties [line items]	LineItems			ifrs-full:DisclosureOfTransactionsBetweenRelatedPartiesLineItems
3595	Compensation of key management personnel	Concept (Monetary)	For Period	Debit	ifrs-full:KeyManagementPersonnelCompensation
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3597	Disclosure of credit risk measurement [Table]	Table	*	*	itub:DisclosureOfCreditRiskMeasurementTable
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3599	Credit Rating Source [Domain]	Member			invest:CreditRatingSourceDomain
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3601	Standard & Poor's [Member]	Member			itub:StandardAndPoorsMember
3602	Fitch [Member]	Member			itub:FitchMember
3603	Internal credit grades [axis]	Axis			ifrs-full:InternalCreditGradesAxis
3604	Entity's total for internal credit grades [member]	Member			ifrs-full:EntitysTotalForInternalCreditGradesMember
3605	Lower risk [Member]	Member			itub:LowerRiskMember
3606	Satisfactory [Member]	Member			itub:SatisfactoryRiskMember
3607	Higher Risk [Member]	Member			itub:HigherRiskMember
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3609	Disclosure of Credit risk measurement [Line Items]	LineItems			itub:DisclosureOfCreditRiskMeasurementLineItems
3610	PD	Concept (Text/String)	For Period		ifrs-full:InformationAboutEntitysDefinitionsOfDefault
3611	External rating	Concept (Text/String)	For Period		ifrs-full:DescriptionOfRatingAgenciesUsed
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3613	Disclosure of credit risk measurement [Table]	Table	*	*	itub:DisclosureOfCreditRiskMeasurementTable
3614	Internal credit grades [axis]	Axis			ifrs-full:InternalCreditGradesAxis
3615	Entity's total for internal credit grades [member]	Member			ifrs-full:EntitysTotalForInternalCreditGradesMember
3616	Lower risk [Member]	Member			itub:LowerRiskMember
3617	Satisfactory [Member]	Member			itub:SatisfactoryRiskMember
3618	Higher Risk [Member]	Member			itub:HigherRiskMember
3619	Impairment [Member]	Member			itub:ImpairmentMember
3620	Range [axis]	Axis			ifrs-full:RangeAxis
3621	Ranges [member]	Member			ifrs-full:RangesMember
3622	Top of range [member]	Member			ifrs-full:TopOfRangeMember
3623	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
3624	Disclosure of Credit risk measurement [Line Items]	LineItems			itub:DisclosureOfCreditRiskMeasurementLineItems
3625	Percentage of probability default range	Concept (Percent)	As Of		itub:ProbabilityOfDefaultRangePercentage
3626	Operations Past Due Period	Concept (xbrli:durationItemType)	For Period		itub:OperationsPastDuePeriod
3627	Renegotiated Operations Past Due Period	Concept (xbrli:durationItemType)	For Period		itub:RenegotiatedOperationsPastDuePeriod
3628	1239 - Disclosure - Management Risks - Credit Risk Exposure (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksCreditRiskExposure
3629	Disclosure of credit risk exposure [table]	Table	*	*	ifrs-full:DisclosureOfCreditRiskExposureTable
3630	Geographical areas [axis]	Axis			ifrs-full:GeographicalAreasAxis
3631	Geographical areas [member]	Member			ifrs-full:GeographicalAreasMember
3632	Brazil [Member]	Member			country:BR
3633	Foreign [Member]	Member			ifrs-full:ForeignCountriesMember
3634	Categories of financial assets [axis]	Axis			ifrs-full:CategoriesOfFinancialAssetsAxis
3635	Financial assets, category [member]	Member			ifrs-full:FinancialAssetsCategoryMember
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3637	Overdraft Accounts [Member]	Member			itub:OverdraftAccountsMember
3638	Credit Cards [Member]	Member			itub:CreditCardsMember
3639	Other Pre Approved Limits [Member]	Member			itub:OtherPreApprovedLimitsMember
3640	Classes of financial instruments [axis]	Axis			ifrs-full:ClassesOfFinancialInstrumentsAxis
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3642	Financial Guarantees Provided [Member]	Member			itub:FinancialGuaranteesProvidedMember
3643	Letters Of Credit To Be Released [Member]	Member			itub:LettersOfCreditToBeReleasedMember
3644	Commitments To Be Released [Member]	Member			itub:CommitmentsToBeReleasedMember
3645	Disclosure of credit risk exposure [line items]	LineItems			ifrs-full:DisclosureOfCreditRiskExposureLineItems
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3647	Securities purchased under agreements to resell	Concept (Monetary)	As Of	Debit	ifrs-full:ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed
3648	Financial assets held for trading	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
3649	Financial assets designated at fair value through profit or loss	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLoss
3650	Derivatives	Concept (Monetary)	As Of	Debit	ifrs-full:DerivativeFinancialAssets
3651	Available-for-sale financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAvailableforsale
3652	Held-to-maturity financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:HeldtomaturityInvestments
3653	Loan operations and lease operations	Concept (Monetary)	As Of	Debit	itub:LoanOperationsAndLeaseOperationsPortfolio
3654	Other financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:OtherFinancialAssets
3655	Off balance sheet	Concept (Monetary)	As Of	Credit	itub:OffBalanceSheetExposure
3656	Credit risk exposure	Concept (Monetary)	As Of		ifrs-full:CreditExposure
3657	1240 - Disclosure - Management Risks - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksAdditionalInformation
3658	Disclosure of credit risk measurement [Table]	Table	*	*	itub:DisclosureOfCreditRiskMeasurementTable
3659	Types of risks [axis]	Axis			ifrs-full:TypesOfRisksAxis
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3661	Liquidity risk [member]	Member			ifrs-full:LiquidityRiskMember
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3663	Loans exposure represented by low probability of default [Member]	Member			itub:LoansExposureRepresentedByLowProbabilityOfDefaultMember
3664	Loans exposure represented by overdue credits not impaired [Member]	Member			itub:LoansExposureRepresentedByOverdueCreditsNotImpairedMember
3665	Range [axis]	Axis			ifrs-full:RangeAxis
3666	Ranges [member]	Member			ifrs-full:RangesMember
3667	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
3668	Average [Member]	Member			itub:AverageMember
3669	Categories of financial assets [axis]	Axis			ifrs-full:CategoriesOfFinancialAssetsAxis
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3672	Funding [Member]	Member			itub:FundingMember
3673	Total assets [Member]	Member			itub:TotalAssetsMember
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3675	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
3676	0-30 days [Member]	Member			ifrs-full:NotLaterThanOneMonthMember
3677	Disclosure of Credit risk measurement [Line Items]	LineItems			itub:DisclosureOfCreditRiskMeasurementLineItems
3678	Percentage of maximum exposure to the quality of the financial assets	Concept (Percent)	For Period		itub:MaximumPercentageOfExposureToRisk
3679	Non-collateralized loans	Concept (Monetary)	For Period	Credit	itub:NonCollateralizedLoans
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3684	Percentage of VaR of total stockholders' equity	Concept (Percent)	For Period		itub:PercentageOfValueAtRisk
3685	Assets required to standardize liquidity coverage ratio	Concept (Monetary)	As Of	Debit	itub:AssetsRequiredToStandardizeLiquidityCoverageRatio
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3689	Liquid assets	Concept (Monetary)	As Of	Debit	itub:LiquidFinancialAssets
3690	Percentage of financial assets	Concept (Percent)	As Of		itub:PercentageOfFinancialAssets
3691	1241 - Disclosure - Management Risks - Maximum Exposure of Loan Operations and Lease Operations Portfolio Segregated By Business Sector (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksMaximumExposureOfLoanOperationsAndLeaseOperationsPortfolioSegregatedByBusinessSector
3692	Disclosure of credit risk exposure [table]	Table	*	*	ifrs-full:DisclosureOfCreditRiskExposureTable
3693	Entity Sector Industry Classifications, Sector [Axis]	Axis			dei:EntitySectorIndustryClassificationsSectorAxis
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3697	Services [Member]	Member			itub:ServicesMember
3698	Natural resources [Member]	Member			itub:NaturalResourcesMember
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3701	Disclosure of credit risk exposure [line items]	LineItems			ifrs-full:DisclosureOfCreditRiskExposureLineItems
3702	Loan operations and lease operations portfolio	Concept (Monetary)	As Of	Debit	itub:LoanOperationsAndLeaseOperationsPortfolioGross
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3705	Disclosure of credit risk exposure [table]	Table	*	*	ifrs-full:DisclosureOfCreditRiskExposureTable
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3715	Disclosure of credit risk exposure [line items]	LineItems			ifrs-full:DisclosureOfCreditRiskExposureLineItems
3716	Other financial assets	Concept (Monetary)	As Of	Debit	itub:MaximumExposureOfOtherFinancialAssets
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3719	Disclosure of financial assets that are either past due or impaired [table]	Table	*	*	ifrs-full:DisclosureOfFinancialAssetsThatAreEitherPastDueOrImpairedTable
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3723	Loans overdue not impaired [Member]	Member			ifrs-full:FinancialAssetsPastDueButNotImpairedMember
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3725	Internal credit grades [axis]	Axis			ifrs-full:InternalCreditGradesAxis
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3727	Lower risk [Member]	Member			itub:LowerRiskMember
3728	Satisfactory [Member]	Member			itub:SatisfactoryRiskMember
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3730	Impairment [Member]	Member			itub:ImpairmentMember
3731	Disclosure of financial assets that are either past due or impaired [line items]	LineItems			ifrs-full:DisclosureOfFinancialAssetsThatAreEitherPastDueOrImpairedLineItems
3732	Loan operations and lease operations portfolio	Concept (Monetary)	As Of	Debit	itub:LoanOperationsAndLeaseOperationsPortfolioGross
3733	Percentage of loan operations and lease operations portfolio	Concept (Percent)	For Period		itub:PercentageOfLoanOperationsAndLeaseOperationsPortfolio
3734	1244 - Disclosure - Management Risks - Summary of Breakdown of Indicators of Credit Quality (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfBreakdownOfIndicatorsOfCreditQuality
3735	Disclosure of credit quality [Table]	Table	*	*	itub:DisclosureOfCreditQualityTable
3736	Internal credit grades [axis]	Axis			ifrs-full:InternalCreditGradesAxis
3737	Entity's total for internal credit grades [member]	Member			ifrs-full:EntitysTotalForInternalCreditGradesMember
3738	Lower risk [Member]	Member			itub:LowerRiskMember
3739	Satisfactory [Member]	Member			itub:SatisfactoryRiskMember
3740	Higher Risk [Member]	Member			itub:HigherRiskMember
3741	Impairment [Member]	Member			itub:ImpairmentMember
3742	Borrowings by name [axis]	Axis			ifrs-full:BorrowingsByNameAxis
3743	Borrowings by name [member]	Member			ifrs-full:BorrowingsByNameMember
3744	Individuals [Member]	Member			itub:IndividualsMember
3745	Classes of financial instruments [axis]	Axis			ifrs-full:ClassesOfFinancialInstrumentsAxis
3746	Financial instruments, class [member]	Member			ifrs-full:ClassesOfFinancialInstrumentsMember
3747	Credit Cards [Member]	Member			itub:CreditCardsMember
3748	Personal loan [Member]	Member			itub:PersonalLoanMember
3749	Payroll loans [Member]	Member			itub:PayrollLoansMember
3750	Mortgages [member]	Member			ifrs-full:MortgagesMember
3751	Corporate loans [member]	Member			ifrs-full:CorporateLoansMember
3752	Small and medium businesses [Member]	Member			itub:SmallAndMediumBusinessesMember
3753	Foreign loans - Latin America [Member]	Member			itub:ForeignLoansMember
3754	Geographical areas [axis]	Axis			ifrs-full:GeographicalAreasAxis
3755	Geographical areas [member]	Member			ifrs-full:GeographicalAreasMember
3756	Foreign [Member]	Member			ifrs-full:ForeignCountriesMember
3757	Classes of assets [axis]	Axis			ifrs-full:ClassesOfAssetsAxis
3758	Assets [member]	Member			ifrs-full:ClassesOfAssetsMember
3759	Vehicles [member]	Member			ifrs-full:VehiclesMember
3760	Disclosure of Credit Quality [Line Items]	LineItems			itub:DisclosureOfCreditQualityLineItems
3761	Loan operations and lease operations portfolio	Concept (Monetary)	As Of	Debit	itub:LoanOperationsAndLeaseOperationsPortfolioGross
3762	Percentage of loan operations and lease operations portfolio	Concept (Percent)	For Period		itub:PercentageOfLoanOperationsAndLeaseOperationsPortfolio
3763	1245 - Disclosure - Management Risks - Summary of Breakdown of Loans Operations and Lease Operations Portfolio Not Overdue and Not Impaired (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfBreakdownOfLoansOperationsAndLeaseOperationsPortfolioNotOverdueAndNotImpaired
3764	Credit Quality Of Neither Past Due Nor Impaired Financial Assets [Table]	Table	*	*	itub:CreditQualityOfNeitherPastDueNorImpairedFinancialAssetsTable
3765	Impairment of financial assets [axis]	Axis			ifrs-full:ImpairmentOfFinancialAssetsAxis
3766	Entity's total for impairment of financial assets [member]	Member			ifrs-full:EntitysTotalForImpairmentOfFinancialAssetsMember
3767	Loans not overdue and not impaired [Member]	Member			ifrs-full:FinancialAssetsNeitherPastDueNorImpairedMember
3768	Internal credit grades [axis]	Axis			ifrs-full:InternalCreditGradesAxis
3769	Entity's total for internal credit grades [member]	Member			ifrs-full:EntitysTotalForInternalCreditGradesMember
3770	Lower risk [Member]	Member			itub:LowerRiskMember
3771	Satisfactory [Member]	Member			itub:SatisfactoryRiskMember
3772	Higher Risk [Member]	Member			itub:HigherRiskMember
3773	Credit impairment of financial instruments [axis]	Axis			ifrs-full:CreditImpairmentOfFinancialInstrumentsAxis
3774	Credit impairment of financial instruments [member]	Member			ifrs-full:CreditImpairmentOfFinancialInstrumentsMember
3775	Individually evaluated [Member]	Member			ifrs-full:FinancialAssetsIndividuallyAssessedForCreditLossesMember
3776	Collectively evaluated [Member]	Member			ifrs-full:FinancialAssetsCollectivelyAssessedForCreditLossesMember
3777	Borrowings by name [axis]	Axis			ifrs-full:BorrowingsByNameAxis
3778	Borrowings by name [member]	Member			ifrs-full:BorrowingsByNameMember
3779	Individuals [Member]	Member			itub:IndividualsMember
3780	Classes of financial instruments [axis]	Axis			ifrs-full:ClassesOfFinancialInstrumentsAxis
3781	Financial instruments, class [member]	Member			ifrs-full:ClassesOfFinancialInstrumentsMember
3782	Large companies [Member]	Member			itub:LargeCompaniesMember
3783	Credit Card [Member]	Member			itub:CreditCardMember
3784	Personal loan [Member]	Member			itub:PersonalLoanMember
3785	Payroll loans [Member]	Member			itub:PayrollLoansMember
3786	Mortgages [member]	Member			ifrs-full:MortgagesMember
3787	Small and medium businesses [Member]	Member			itub:SmallAndMediumBusinessesMember
3788	Foreign loans - Latin America [Member]	Member			itub:ForeignLoansMember
3789	Classes of assets [axis]	Axis			ifrs-full:ClassesOfAssetsAxis
3790	Assets [member]	Member			ifrs-full:ClassesOfAssetsMember
3791	Vehicles [member]	Member			ifrs-full:VehiclesMember
3792	Geographical areas [axis]	Axis			ifrs-full:GeographicalAreasAxis
3793	Geographical areas [member]	Member			ifrs-full:GeographicalAreasMember
3794	Foreign [Member]	Member			ifrs-full:ForeignCountriesMember
3795	Credit Quality Of Neither Past Due Nor Impaired Financial Assets [Line Items]	LineItems			itub:CreditQualityOfNeitherPastDueNorImpairedFinancialAssetsLineItems
3796	Loan operations and lease operations portfolio	Concept (Monetary)	As Of	Debit	itub:LoanOperationsAndLeaseOperationsPortfolioGross
3797	1246 - Disclosure - Management Risks - Summary of Breakdown of Loans Operations and Lease Operations Portfolio Loans Overdue Not Impaired (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfBreakdownOfLoansOperationsAndLeaseOperationsPortfolioLoansOverdueNotImpaired
3798	Credit Quality Of Neither Past Due Nor Impaired Financial Assets [Table]	Table	*	*	itub:CreditQualityOfNeitherPastDueNorImpairedFinancialAssetsTable
3799	Maturity [axis]	Axis			ifrs-full:MaturityAxis
3800	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
3801	0-30 days [Member]	Member			ifrs-full:NotLaterThanOneMonthMember
3802	Impairment of financial assets [axis]	Axis			ifrs-full:ImpairmentOfFinancialAssetsAxis
3803	Entity's total for impairment of financial assets [member]	Member			ifrs-full:EntitysTotalForImpairmentOfFinancialAssetsMember
3804	Loans overdue not impaired [Member]	Member			ifrs-full:FinancialAssetsPastDueButNotImpairedMember
3805	Past due status [axis]	Axis			ifrs-full:PastDueStatusAxis
3806	Past due status [member]	Member			ifrs-full:PastDueStatusMember
3807	31-60 days [Member]	Member			ifrs-full:LaterThanOneMonthAndNotLaterThanTwoMonthsMember
3808	61-90 days [Member]	Member			ifrs-full:LaterThanTwoMonthsAndNotLaterThanThreeMonthsMember
3809	Borrowings by name [axis]	Axis			ifrs-full:BorrowingsByNameAxis
3810	Borrowings by name [member]	Member			ifrs-full:BorrowingsByNameMember
3811	Individuals [Member]	Member			itub:IndividualsMember
3812	Classes of financial instruments [axis]	Axis			ifrs-full:ClassesOfFinancialInstrumentsAxis
3813	Financial instruments, class [member]	Member			ifrs-full:ClassesOfFinancialInstrumentsMember
3814	Credit Card [Member]	Member			itub:CreditCardMember
3815	Personal loan [Member]	Member			itub:PersonalLoanMember
3816	Payroll loans [Member]	Member			itub:PayrollLoansMember
3817	Mortgages [member]	Member			ifrs-full:MortgagesMember
3818	Corporate loans [member]	Member			ifrs-full:CorporateLoansMember
3819	Small and medium businesses [Member]	Member			itub:SmallAndMediumBusinessesMember
3820	Foreign loans - Latin America [Member]	Member			itub:ForeignLoansMember
3821	Classes of assets [axis]	Axis			ifrs-full:ClassesOfAssetsAxis
3822	Assets [member]	Member			ifrs-full:ClassesOfAssetsMember
3823	Vehicles [member]	Member			ifrs-full:VehiclesMember
3824	Geographical areas [axis]	Axis			ifrs-full:GeographicalAreasAxis
3825	Geographical areas [member]	Member			ifrs-full:GeographicalAreasMember
3826	Foreign [Member]	Member			ifrs-full:ForeignCountriesMember
3827	Credit Quality Of Neither Past Due Nor Impaired Financial Assets [Line Items]	LineItems			itub:CreditQualityOfNeitherPastDueNorImpairedFinancialAssetsLineItems
3828	Loan operations and lease operations portfolio	Concept (Monetary)	As Of	Debit	itub:LoanOperationsAndLeaseOperationsPortfolioGross
3829	1247 - Disclosure - Management Risks - Summary of Financial Assets Individually Evaluated Classified by Rating (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfFinancialAssetsIndividuallyEvaluatedClassifiedByRating
3830	Disclosure of financial assets individually evaluated classified by rating[Table]	Table	*	*	itub:DisclosureOfFinancialAssetsIndividuallyEvaluatedClassifiedByRatingTable
3831	Categories of financial assets [axis]	Axis			ifrs-full:CategoriesOfFinancialAssetsAxis
3832	Financial assets, category [member]	Member			ifrs-full:FinancialAssetsCategoryMember
3833	Interbank deposits and securities purchased under agreements to resell [Member]	Member			itub:InterbankDepositsAndSecuritiesPurchasedUnderAgreementsToResellMember
3834	Held-for-trading financial assets [Member]	Member			ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTradingCategoryMember
3835	Financial assets designated at fair value through profit or loss [Member]	Member			ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossCategoryMember
3836	Derivative assets [Member]	Member			itub:DerivativeAssetsMember
3837	Available-for-sale financial assets [Member]	Member			ifrs-full:FinancialAssetsAvailableforsaleCategoryMember
3838	Held-to-maturity financial assets [Member]	Member			ifrs-full:HeldtomaturityInvestmentsCategoryMember
3839	Internal credit grades [axis]	Axis			ifrs-full:InternalCreditGradesAxis
3840	Entity's total for internal credit grades [member]	Member			ifrs-full:EntitysTotalForInternalCreditGradesMember
3841	Lower risk [Member]	Member			itub:LowerRiskMember
3842	Satisfactory [Member]	Member			itub:SatisfactoryRiskMember
3843	Higher Risk [Member]	Member			itub:HigherRiskMember
3844	Impairment [Member]	Member			itub:ImpairmentMember
3845	Disclosure of financial assets individually evaluated classified by rating [Line Items]	LineItems			itub:DisclosureOfFinancialAssetsIndividuallyEvaluatedClassifiedByRatingLineItems
3846	Other financial assets, individually evaluated, classified by rating	Concept (Monetary)	As Of	Debit	itub:MaximumExposureOfOtherFinancialAssets
3847	Other financial assets, individually evaluated, classified by rating, percentage	Concept (Percent)	For Period		itub:PercentageOfMaximumExposureOfOtherFinancialAssets
3848	1248 - Disclosure - Management Risks - Summary of Collateral Held for Loan and Lease Operations Portfolio (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfCollateralHeldForLoanAndLeaseOperationsPortfolio
3849	Disclosure of collateral held for loan and lease operations portfolio [Table]	Table	*	*	itub:DisclosureOfCollateralHeldForLoanAndLeaseOperationsPortfolioTable
3850	Borrowings by name [axis]	Axis			ifrs-full:BorrowingsByNameAxis
3851	Borrowings by name [member]	Member			ifrs-full:BorrowingsByNameMember
3852	Individuals [Member]	Member			itub:IndividualsMember
3853	Classes of financial instruments [axis]	Axis			ifrs-full:ClassesOfFinancialInstrumentsAxis
3854	Financial instruments, class [member]	Member			ifrs-full:ClassesOfFinancialInstrumentsMember
3855	Personal loan [Member]	Member			itub:PersonalLoanMember
3856	Mortgages [member]	Member			ifrs-full:MortgagesMember
3857	Small and medium businesses [Member]	Member			itub:SmallAndMediumBusinessesMember
3858	Foreign loans - Latin America [Member]	Member			itub:ForeignLoansMember
3859	Classes of assets [axis]	Axis			ifrs-full:ClassesOfAssetsAxis
3860	Assets [member]	Member			ifrs-full:ClassesOfAssetsMember
3861	Vehicles [member]	Member			ifrs-full:VehiclesMember
3862	Geographical areas [axis]	Axis			ifrs-full:GeographicalAreasAxis
3863	Geographical areas [member]	Member			ifrs-full:GeographicalAreasMember
3864	Foreign [Member]	Member			ifrs-full:ForeignCountriesMember
3865	Disclosure of collateral held for loan and lease operations portfolio [Line Items]	LineItems			itub:DisclosureOfCollateralHeldForLoanAndLeaseOperationsPortfolioLineItems
3866	Carrying value of the assets	Concept (Monetary)	For Period	Debit	itub:CollateralAssetsCarryingValueOverCollateralizedAssets
3867	Fair value of collateral	Concept (Monetary)	For Period	Debit	itub:CollateralFairValueOverCollateralizedAssets
3868	Carrying value of the assets	Concept (Monetary)	For Period	Debit	itub:CollateralAssetsCarryingValueUnderCollateralizedAssets
3869	Fair value of collateral	Concept (Monetary)	For Period	Debit	itub:CollateralFairValueUnderCollateralizedAssets
3870	1249 - Disclosure - Management Risks - Summary of Assets Repossessed (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfAssetsRepossessed
3871	Implied Table	Table	*	*	implied:Table
3872	Disclosure of assets repossessed [Abstract]	Abstract			itub:DisclosureOfAssetsRepossessedAbstract
3873	Real estate not for own use	Concept (Monetary)	For Period	Debit	itub:AssetsRepossessedInPeriodRealEstateNotForOwnUse
3874	Residential properties - mortgage loans	Concept (Monetary)	For Period	Debit	itub:AssetsRepossessedInPeriodResidentialPropertiesMortgageLoans
3875	Vehicles - linked to loan operations	Concept (Monetary)	For Period	Debit	itub:AssetsRepossessedInPeriodVehiclesLinkedToLoanOperations
3876	Other (vehicles / furniture / equipments) - dation	Concept (Monetary)	For Period	Debit	itub:AssetsRepossessedInPeriodOther
3877	Total	Concept (Monetary)	For Period	Debit	itub:AssetsRepossessedInPeriod
3878	1250 - Disclosure - Management Risks - Summary of VaR Total - Historical Simulation (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfVaRTotalHistoricalSimulation
3879	Disclosure of Value at Risk historical simulation [table]	Table	*	*	itub:DisclosureOfValueAtRiskHistoricalSimulationTable
3880	Range [axis]	Axis			ifrs-full:RangeAxis
3881	Ranges [member]	Member			ifrs-full:RangesMember
3882	Average [Member]	Member			itub:AverageMember
3883	Bottom of range [member]	Member			ifrs-full:BottomOfRangeMember
3884	Top of range [member]	Member			ifrs-full:TopOfRangeMember
3885	Types of risks [axis]	Axis			ifrs-full:TypesOfRisksAxis
3886	Risks [member]	Member			ifrs-full:TypesOfRisksMember
3887	Interest rates [Member]	Member			ifrs-full:InterestRateRiskMember
3888	Currency risk [member]	Member			ifrs-full:CurrencyRiskMember
3889	Equity price risk [member]	Member			ifrs-full:EquityPriceRiskMember
3890	Commodity price risk [member]	Member			ifrs-full:CommodityPriceRiskMember
3891	Risk diversification effect [member]	Member			ifrs-full:RiskDiversificationEffectMember
3892	Disclosure of Value at Risk historical simulation [Line Items]	LineItems			itub:DisclosureOfValueAtRiskHistoricalSimulationLineItems
3893	Risk factor group	Concept (Monetary)	As Of		ifrs-full:ValueAtRisk
3894	1251 - Disclosure - Management Risks - Summary of Position of Accounts Subject to Currency Risk (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfPositionOfAccountsSubjectToCurrencyRisk
3895	Disclosure of position of accounts subject to interest rate risk [Table]	Table	*	*	itub:DisclosureOfPositionOfAccountsSubjectToInterestRateRiskTable
3896	Maturity [axis]	Axis			ifrs-full:MaturityAxis
3897	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
3898	0-30 days [Member]	Member			ifrs-full:NotLaterThanOneMonthMember
3899	31-180 days [Member]	Member			ifrs-full:LaterThanOneMonthAndNotLaterThanSixMonthsMember
3900	181-365 days [Member]	Member			ifrs-full:LaterThanSixMonthsAndNotLaterThanOneYearMember
3901	1-5 years [Member]	Member			ifrs-full:LaterThanOneYearAndNotLaterThanFiveYearsMember
3902	Over 5 years [Member]	Member			ifrs-full:LaterThanFiveYearsMember
3903	Types of risks [axis]	Axis			ifrs-full:TypesOfRisksAxis
3904	Risks [member]	Member			ifrs-full:TypesOfRisksMember
3905	Interest rates [Member]	Member			ifrs-full:InterestRateRiskMember
3906	Disclosure of position of accounts subject to interest rate risk [Line Items]	LineItems			itub:DisclosureOfPositionOfAccountsSubjectToInterestRateRiskLineItems
3907	Interest-bearing assets	Concept (Monetary)	As Of	Debit	itub:InterestBearingAssets
3908	Interbank deposits	Concept (Monetary)	As Of	Debit	ifrs-full:LoansAndAdvancesToBanks
3909	Securities purchased under agreements to resell	Concept (Monetary)	As Of	Debit	ifrs-full:ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed
3910	Central Bank compulsory deposits	Concept (Monetary)	As Of	Debit	ifrs-full:MandatoryReserveDepositsAtCentralBanks
3911	Held-for-trading financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
3912	Financial assets held for trading and designated at fair value through profit or loss	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLoss
3913	Available-for-sale financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAvailableforsale
3914	Held-to-maturity financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:HeldtomaturityInvestments
3915	Derivatives	Concept (Monetary)	As Of	Debit	ifrs-full:DerivativeFinancialAssets
3916	Loan and lease operations portfolio	Concept (Monetary)	As Of	Debit	itub:LoanOperationsAndLeaseOperationsPortfolioGross
3917	Interest-bearing liabilities	Concept (Monetary)	As Of	Credit	itub:InterestBearingLiabilities
3918	Savings deposits	Concept (Monetary)	As Of	Credit	itub:SavingsDeposits
3919	Time deposits	Concept (Monetary)	As Of	Credit	itub:TimeDeposit
3920	Interbank deposits	Concept (Monetary)	As Of	Credit	ifrs-full:DepositsFromBanks
3921	Deposits received under repurchase agreements	Concept (Monetary)	For Period	Debit	itub:DepositsReceivedUnderRepurchaseAgreements
3922	Interbank market	Concept (Monetary)	As Of	Credit	itub:InterbankMarketDebt
3923	Institutional market	Concept (Monetary)	As Of	Credit	itub:InstitutionalMarketDebt
3924	Derivatives	Concept (Monetary)	As Of	Credit	ifrs-full:DerivativeFinancialLiabilities
3925	Financial liabilities held for trading	Concept (Monetary)	As Of	Credit	ifrs-full:FinancialLiabilitiesAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
3926	Liabilities for capitalization plans	Concept (Monetary)	As Of	Credit	itub:LiabilitiesForCapitalizationPlans
3927	Difference asset / liability	Concept (Monetary)	As Of	Debit	ifrs-full:NetAssetsLiabilities
3928	Cumulative difference	Concept (Monetary)	As Of	Debit	itub:CumulativeDifference
3929	Ratio of cumulative difference to total interest-bearing assets	Concept (Percent)	As Of		itub:RatioOfCumulativeDifferenceToInterestBearingAssets
3930	1252 - Disclosure - Management Risks - Summary of Position of Accounts Subject to Interest Rate Risk (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfPositionOfAccountsSubjectToInterestRateRisk
3931	Disclosure of position of accounts subject to currency risk [Table]	Table	*	*	itub:DisclosureOfPositionOfAccountsSubjectToCurrencyRiskTable
3932	Currency [Axis]	Axis			us-gaap:CurrencyAxis
3933	All Currencies [Domain]	Member			currency:AllCurrenciesDomain
3934	United States of America, Dollars	Member			currency:USD
3935	Chile, Pesos	Member			currency:CLP
3936	Other [Member]	Member			itub:OtherCurrenciesMember
3937	Types of risks [axis]	Axis			ifrs-full:TypesOfRisksAxis
3938	Risks [member]	Member			ifrs-full:TypesOfRisksMember
3939	Currency risk [member]	Member			ifrs-full:CurrencyRiskMember
3940	Disclosure of position of accounts subject to currency risk [Line Items]	LineItems			itub:DisclosureOfPositionOfAccountsSubjectToCurrencyRiskLineItems
3941	Assets	Abstract			ifrs-full:AssetsAbstract
3942	Cash and deposits on demand	Concept (Monetary)	As Of	Debit	itub:CashAndDepositsOnDemand
3943	Central Bank compulsory deposits	Concept (Monetary)	As Of	Debit	itub:CentralBankCompulsoryDeposits
3944	Interbank deposits	Concept (Monetary)	As Of	Debit	ifrs-full:ShorttermDepositsClassifiedAsCashEquivalents
3945	Securities purchased under agreements to resell	Concept (Monetary)	As Of	Debit	ifrs-full:ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed
3946	Financial assets held for trading	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
3947	Financial assets designated at fair value through profit or loss	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLoss
3948	Derivatives	Concept (Monetary)	As Of	Debit	ifrs-full:DerivativeFinancialAssets
3949	Available-for-sale financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssetsAvailableforsale
3950	Held-to-maturity financial assets	Concept (Monetary)	As Of	Debit	ifrs-full:HeldtomaturityInvestments
3951	Loan operations and lease operations portfolio, net	Concept (Monetary)	As Of	Debit	itub:LoanOperationsAndLeaseOperationsPortfolio
3952	Total assets	Concept (Monetary)	As Of	Debit	ifrs-full:Assets
3953	Liabilities	Abstract			ifrs-full:LiabilitiesAbstract
3954	Deposits	Concept (Monetary)	As Of	Credit	ifrs-full:DepositsFromCustomers
3955	Securities sold under repurchase agreements	Concept (Monetary)	As Of	Credit	ifrs-full:RepurchaseAgreementsAndCashCollateralOnSecuritiesLent
3956	Financial liabilities held for trading	Concept (Monetary)	As Of	Credit	ifrs-full:FinancialLiabilitiesAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading
3957	Derivatives	Concept (Monetary)	As Of	Credit	ifrs-full:DerivativeFinancialLiabilities
3958	Interbank market debt	Concept (Monetary)	As Of	Credit	itub:InterbankMarketDebt
3959	Institutional market debt	Concept (Monetary)	As Of	Credit	itub:InstitutionalMarketDebt
3960	Total liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:Liabilities
3961	Net position	Concept (Monetary)	As Of	Debit	ifrs-full:NetAssetsLiabilities
3962	1253 - Disclosure - Management Risks - Summary of Index Calculation (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfIndexCalculation
3963	Disclosure Of Index Calculation [Table]	Table	*	*	itub:DisclosureOfIndexCalculationTable
3964	Types of risks [axis]	Axis			ifrs-full:TypesOfRisksAxis
3965	Risks [member]	Member			ifrs-full:TypesOfRisksMember
3966	Liquidity risk [member]	Member			ifrs-full:LiquidityRiskMember
3967	Disclosure Of Index Calculation [LineItems]	LineItems			itub:DisclosureOfIndexCalculationLineItems
3968	Total high-quality liquid assets	Concept (Monetary)	As Of	Debit	itub:HighQualityLiquidAssetsAdjustedAmount
3969	Total potential cash outflows	Concept (Monetary)	For Period	Credit	itub:PotentialCashOutflowsAdjustedAmount
3970	Liquidity Coverage Ratio (%)	Concept (Percent)	For Period		itub:LiquidityCoverageRatio
3971	1254 - Disclosure - Management Risks - Summary of Funding from Clients (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfFundingFromClients
3972	Disclosure of Sources of Funding [Table]	Table	*	*	itub:DisclosureOfSourcesOfFundingTable
3973	Categories of financial liabilities [axis]	Axis			ifrs-full:CategoriesOfFinancialLiabilitiesAxis
3974	Financial liabilities, category [member]	Member			ifrs-full:FinancialLiabilitiesCategoryMember
3975	Demand deposits [Member]	Member			itub:DemandDeposits1Member
3976	Savings deposits [Member]	Member			itub:SavingDepositsMember
3977	Time deposits [Member]	Member			itub:TimeDepositsMember
3978	Other [Member]	Member			itub:OtherDepositsMember
3979	Security Deposits [Member]	Member			itub:SecurityDepositsMember
3980	Issued debt [Member]	Member			itub:IssuedDebtMember
3981	Subordinated debt [Member]	Member			us-gaap:SubordinatedDebtMember
3982	Maturity [axis]	Axis			ifrs-full:MaturityAxis
3983	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
3984	0-30 days [Member]	Member			ifrs-full:NotLaterThanOneMonthMember
3985	Categories of related parties [axis]	Axis			ifrs-full:CategoriesOfRelatedPartiesAxis
3986	Entity's total for related parties [member]	Member			ifrs-full:EntitysTotalForRelatedPartiesMember
3987	ITAU UNIBANCO HOLDING [Member]	Member			itub:ItauUnibancoHoldingMember
3988	Disclosure of Sources of Funding [Line Items]	LineItems			itub:DisclosureOfSourcesOfFundingLineItems
3989	Deposits	Concept (Monetary)	As Of	Credit	ifrs-full:DepositsFromCustomers
3990	Demand deposits	Concept (Monetary)	As Of	Credit	ifrs-full:BalancesOnDemandDepositsFromCustomers
3991	Savings deposits	Concept (Monetary)	As Of	Credit	itub:BalancesOnSavingsDepositsFromCustomers
3992	Time deposits	Concept (Monetary)	As Of	Credit	ifrs-full:BalancesOnTermDepositsFromCustomers
3993	Other	Concept (Monetary)	As Of	Credit	ifrs-full:BalancesOnOtherDepositsFromCustomers
3994	Funds from acceptances and issuance of securities	Concept (Monetary)	As Of	Credit	itub:FundsFromAcceptancesAndIssuanceOfSecurities
3995	Funds from own issue	Concept (Monetary)	As Of	Credit	itub:FundsFromOwnIssue
3996	Subordinated debt	Concept (Monetary)	As Of	Credit	ifrs-full:SubordinatedLiabilities
3997	Total	Concept (Monetary)	As Of	Credit	itub:FundsFromCustomers
3998	Percentage of funding from clients	Concept (Percent)	For Period		itub:PercentageOfAggregateFundsFromCustomers
3999	1255 - Disclosure - Management Risks - Summary of Liquidity Indicators (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfLiquidityIndicators
4000	Implied Table	Table	*	*	implied:Table
4001	Disclosure of liquidity risk indicators [abstract]	Abstract			itub:DisclosureOfLiquidityRiskIndicatorsAbstract
4002	Net assets / funds within 30 days	Concept (Percent)	As Of		itub:PercentageOfNetAssetsToFundsWithinThirtyDays
4003	Net assets / total funds	Concept (Percent)	As Of		itub:PercentageOfNetAssetsToTotalFunds
4004	Net assets / total assets	Concept (Percent)	As Of		itub:PercentageOfNetAssetsToTotalAssets
4005	1256 - Disclosure - Management Risks - Summary of Liquidity Indicators (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfLiquidityIndicatorsParenthetical
4006	Implied Table	Table	*	*	implied:Table
4007	Disclosure of liquidity risk indicators [abstract]	Abstract			itub:DisclosureOfLiquidityRiskIndicatorsAbstract
4008	Present value of financial assets	Concept (Monetary)	As Of	Debit	itub:PresentValueOfLiquidFinancialAssets
4009	1257 - Disclosure - Management Risks - Summary of Assets and Liabilities According to Their Remaining Contractual Maturities, Considering Their Undiscounted Flows (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfAssetsAndLiabilitiesAccordingToTheirRemainingContractualMaturitiesConsideringTheirUndiscountedFlows
4010	Disclosure of assets and liabilities according to their remaining contractual maturities [Table]	Table	*	*	itub:DisclosureOfAssetsAndLiabilitiesAccordingToTheirRemainingContractualMaturitiesTable
4011	Maturity [axis]	Axis			ifrs-full:MaturityAxis
4012	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
4013	0-30 days [Member]	Member			ifrs-full:NotLaterThanOneMonthMember
4014	31 - 365 days [Member]	Member			itub:ThirtyOneToThreeHundredAndSixtyFiveDaysDueMember
4015	366 - 720 days [Member]	Member			itub:ThreeHundredAndSixtySixToSevenHundredAndTwentyDaysDueMember
4016	Over 720 days [Member]	Member			itub:OverSevenHundredAndTwentyDaysDueMember
4017	Classes of financial assets [axis]	Axis			ifrs-full:ClassesOfFinancialAssetsAxis
4018	Financial assets, class [member]	Member			ifrs-full:FinancialAssetsMember
4019	Securities purchased under agreements to resell - Funded position [Member]	Member			itub:FundedPositionMember
4020	Securities purchased under agreements to resell - Financed position [Member]	Member			itub:FinancedPositionMember
4021	Interbank deposits [Member]	Member			itub:InterbankDepositsMember
4022	Equity securities - available-for-sale [Member]	Member			itub:EquitySecuritiesAvailableforsaleMember
4023	Securities In Reverse Repurchase Transaction [Member]	Member			itub:SecuritiesInReverseRepurchaseTransactionMember
4024	Debt securities - available-for-sale [Member]	Member			itub:DebtSecuritiesAvailableforsaleMember
4025	Securities sold under repurchase agreements [Member]	Member			itub:SecuritiesSoldUnderRepurchaseAgreementsMember
4026	Swap [Member]	Member			ifrs-full:SwapContractMember
4027	Option contract [member]	Member			ifrs-full:OptionContractMember
4028	Forward contract [member]	Member			ifrs-full:ForwardContractMember
4029	Other derivative financial instruments [Member]	Member			itub:OtherDerivativeFinancialInstrumentsMember
4030	Demand deposits [Member]	Member			itub:DemandDeposits1Member
4031	Savings deposits [Member]	Member			itub:SavingDepositsMember
4032	Time deposits [Member]	Member			itub:TimeDepositsMember
4033	Other [Member]	Member			itub:OtherDepositsMember
4034	Government securities - other countries [Member]	Member			itub:GovernmentSecuritiesMember
4035	Private Securities [Member]	Member			itub:PrivateSecuritiesMember
4036	Foreign Securities [Member]	Member			itub:ForeignSecuritiesMember
4037	Valuation techniques used in fair value measurement [axis]	Axis			ifrs-full:ValuationTechniquesUsedInFairValueMeasurementAxis
4038	Valuation techniques [member]	Member			ifrs-full:ValuationTechniquesMember
4039	Undiscounted cash flows [member]	Member			itub:UndiscountedCashFlowsMember
4040	Disclosure of assets and liabilities according to their remaining contractual maturities [Line Items]	LineItems			itub:DisclosureOfAssetsAndLiabilitiesAccordingToTheirRemainingContractualMaturitiesLineItems
4041	Cash and deposits on demand	Concept (Monetary)	As Of	Debit	itub:CashAndDepositsOnDemand
4042	Interbank investments	Concept (Monetary)	As Of	Debit	ifrs-full:ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed
4043	Securities	Concept (Monetary)	As Of	Debit	itub:SecuritiesIssued
4044	Derivative financial instruments	Concept (Monetary)	As Of	Debit	ifrs-full:DerivativeFinancialAssets
4045	Forward (onshore)	Concept (Monetary)	As Of	Debit	ifrs-full:NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition
4046	Loan and lease operations portfolio	Concept (Monetary)	As Of	Debit	itub:LoanOperationsAndLeaseOperationsPortfolio
4047	Total	Concept (Monetary)	As Of	Debit	ifrs-full:FinancialAssets
4048	Compulsory deposits with the Central Bank of Brazil	Concept (Monetary)	For Period	Debit	itub:AdjustmentsForCompulsoryDepositsWithTheCentralBank
4049	Deposits	Concept (Monetary)	As Of	Credit	ifrs-full:DepositsFromBanks
4050	Compulsory deposits	Concept (Monetary)	As Of	Debit	ifrs-full:MandatoryReserveDepositsAtCentralBanks
4051	Securities sold under repurchase agreements	Concept (Monetary)	As Of	Credit	ifrs-full:RepurchaseAgreementsAndCashCollateralOnSecuritiesLent
4052	Funds from acceptances and issuance of securities	Concept (Monetary)	As Of	Credit	itub:FundsFromAcceptancesAndIssuanceOfSecurities
4053	Borrowing and onlending	Concept (Monetary)	As Of	Credit	ifrs-full:Borrowings
4054	Subordinated debt	Concept (Monetary)	As Of	Credit	ifrs-full:SubordinatedLiabilities
4055	Derivative financial instruments	Concept (Monetary)	As Of	Credit	ifrs-full:DerivativeFinancialLiabilities
4056	Net position	Concept (Monetary)	As Of	Credit	ifrs-full:NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition
4057	Total financial liabilities	Concept (Monetary)	As Of	Credit	ifrs-full:FinancialLiabilities
4058	1258 - Disclosure - Management Risks - Summary of Assets and Liabilities According to Their Remaining Contractual Maturities, Considering Their Undiscounted Flows (Parenthetical) (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfAssetsAndLiabilitiesAccordingToTheirRemainingContractualMaturitiesConsideringTheirUndiscountedFlowsParenthetical
4059	Implied Table	Table	*	*	implied:Table
4060	Disclosure of assets and liabilities according to their remaining contractual maturities [Abstract]	Abstract			itub:DisclosureOfAssetsAndLiabilitiesAccordingToTheirRemainingContractualMaturitiesAbstract
4061	Deposits in Central Bank	Concept (Monetary)	As Of	Debit	ifrs-full:MandatoryReserveDepositsAtCentralBanks
4062	Securities under guarantee transactions	Concept (Monetary)	As Of	Debit	itub:PledgedInGuaranteeOfOperations
4063	Payment to merchants	Concept (Monetary)	For Period	Credit	ifrs-full:PaymentsToAndOnBehalfOfEmployees
4064	Amount of liabilities from transactions related to credit assignments	Concept (Monetary)	As Of	Credit	itub:AmountOfLiabilitiesFromTransactionsRelatedToCreditAssignments
4065	1259 - Disclosure - Management Risks - Summary of Off Balance Sheet (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureManagementRisksSummaryOfOffBalanceSheet
4066	Disclosure of contractual maturities of assets and liabilities and off balance sheet commitments [Table]	Table	*	*	itub:DisclosureOfContractualMaturitiesOfAssetsAndLiabilitiesAndOffBalanceSheetCommitmentsTable
4067	Maturity [axis]	Axis			ifrs-full:MaturityAxis
4068	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
4069	0-30 days [Member]	Member			ifrs-full:NotLaterThanOneMonthMember
4070	31 - 365 days [Member]	Member			itub:ThirtyOneToThreeHundredAndSixtyFiveDaysDueMember
4071	366 - 720 days [Member]	Member			itub:ThreeHundredAndSixtySixToSevenHundredAndTwentyDaysDueMember
4072	Over 720 days [Member]	Member			itub:OverSevenHundredAndTwentyDaysDueMember
4073	Disclosure of contractual maturities of assets and liabilities and off balance sheet commitments [line items]	LineItems			itub:DisclosureOfContractualMaturitiesOfAssetsAndLiabilitiesAndOffBalanceSheetCommitmentsLineItems
4074	Financial Guarantees Provided	Concept (Monetary)	As Of	Credit	itub:FinancialGuarantees
4075	Commitments to be released	Concept (Monetary)	As Of	Credit	itub:Commitments
4076	Letters of credit to be released	Concept (Monetary)	As Of	Credit	itub:LettersOfCredit
4077	Contractual commitments - Fixed assets and Intangible	Concept (Monetary)	As Of	Credit	ifrs-full:ContractualCapitalCommitments
4078	Total	Concept (Monetary)	As Of	Credit	itub:OffBalanceSheetItem
4079	1260 - Disclosure - Supplementary Information - Additional Information (Detail)	Network	*	*	http://imetrix.edgar-online.com/taxonomy/role/DisclosureSupplementaryInformationAdditionalInformation
4080	Disclosure of supplemental financial information [table]	Table	*	*	itub:DisclosureOfSupplementalFinancialInformationTable
4081	Subsidiaries [axis]	Axis			ifrs-full:SignificantInvestmentsInSubsidiariesAxis
4082	Entity's total for subsidiaries [member]	Member			ifrs-full:EntitysTotalForSubsidiariesMember
4083	Itau Seguros S.A. [Member]	Member			itub:ItauSegurosSAMember
4084	Business combinations [axis]	Axis			ifrs-full:BusinessCombinationsAxis
4085	Entity's total for business combinations [member]	Member			ifrs-full:EntitysTotalForBusinessCombinationsMember
4086	XP Holding [Member]	Member			itub:XpHoldingMember
4087	Maturity [axis]	Axis			ifrs-full:MaturityAxis
4088	Aggregated time bands [member]	Member			ifrs-full:AggregatedTimeBandsMember
4089	2020 [Member]	Member			itub:TwoThousandAndTwentyMember
4090	2022 [Member]	Member			itub:TwoThousandTwentyTwoMember
4091	Disclosure of supplemental financial information [line items]	LineItems			itub:DisclosureOfSupplementalFinancialInformationLineItems
4092	Percentage of life insurance operation sold	Concept (Percent)	For Period		itub:PercentageOfLifeInsuranceProductsHeldForSale
4093	Percentage of assets in subsidiary sold	Concept (Percent)	For Period		itub:PercentageOfAssetsInSubsidiaryHeldForSale
4094	Acquisition interest on capital	Concept (Percent)	For Period		itub:AcquisitionInterestOnCapital
4095	Percentage of common stock	Concept (Percent)	For Period		itub:PercentageOfCommonStock
4096	Capital contribution	Concept (Monetary)	For Period	Credit	itub:PaymentsOnCapitalContribution
4097	Amount of share purchase	Concept (Monetary)	For Period	Credit	itub:AmountOfSharesPurchased
4098	Additional interest on equity percentage	Concept (Percent)	As Of		itub:AdditionalInterestOnEquityPercentage