| Standard label: | Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held |
| Name: | us-gaap:OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCreditLossesOnDebtSecuritiesHeld |
| Documentation: | The cumulative amount of credit losses recognized in earnings related to debt securities held for which a portion of an other than temporary impairment (OTTI) was recognized in other comprehensive income (a component of shareholders' equity). |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | As Of (instant) |
| Balance type: | Debit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCreditLossesOnDebtSecuritiesHeld |
| Label | Role | Language |
| Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held | http://www.xbrl.org/2003/role/label | en-US |
| Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held, Ending Balance | http://www.xbrl.org/2003/role/periodEndLabel | en-US |
| Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held, Beginning Balance | http://www.xbrl.org/2003/role/periodStartLabel | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 320 10 50 8B (a) | http://fasb.org/us-gaap/role/ref/legacyRef | 320 |
| FASB Accounting Standards Codification 320 10 50 8B (g) | http://fasb.org/us-gaap/role/ref/legacyRef | 320 |