| Standard label: | Other Comprehensive Loss, Held-to-maturity Security, Adjustment from AOCI for Accretion of Noncredit Portion of OTTI, Tax |
| Name: | us-gaap:OtherComprehensiveLossHeldToMaturitySecurityAdjustmentFromAociForAccretionOfNoncreditPortionOfOttiTax |
| Documentation: | Amount of tax (expense) benefit of adjustment from accumulated other comprehensive loss for accretion of other than temporary impairment (OTTI) on investment in held-to-maturity security. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | For Period (duration) |
| Balance type: | Debit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:OtherComprehensiveLossHeldToMaturitySecurityAdjustmentFromAociForAccretionOfNoncreditPortionOfOttiTax |
| Label | Role | Language |
| Other Comprehensive Loss, Held-to-maturity Security, Adjustment from AOCI for Accretion of Noncredit Portion of OTTI, Tax | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 220 10 45 12 | http://fasb.org/us-gaap/role/ref/legacyRef | 220 |
| FASB Accounting Standards Codification 320 10 35 35A | http://fasb.org/us-gaap/role/ref/legacyRef | 320 |