| Standard label: | Other-than-temporary Impairment Loss, Debt Securities, Held-to-maturity, Accretion of Noncredit Portion, before Tax |
| Name: | us-gaap:OtherThanTemporaryImpairmentLossesInvestmentsAccretionOfNoncreditPortionHeldtomaturitySecuritiesBeforeTax |
| Documentation: | Amount, before tax, of accretion of other-than-temporary impairment (OTTI) related to factors other than credit loss on investment in debt security measured at amortized cost (held-to-maturity). |
| 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:OtherThanTemporaryImpairmentLossesInvestmentsAccretionOfNoncreditPortionHeldtomaturitySecuritiesBeforeTax |
| Label | Role | Language |
| Other-than-temporary Impairment Loss, Debt Securities, Held-to-maturity, Accretion of Noncredit Portion, before Tax | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 320 10 35 35A | http://fasb.org/us-gaap/role/ref/legacyRef | 320 |