| Standard label: | AOCI, Debt Securities, Available-for-sale with Allowance for Credit Loss, Cumulative Gain (Loss), after Tax |
| Name: | us-gaap:AociDebtSecuritiesAvailableForSaleWithAllowanceForCreditLossCumulativeGainLossAfterTax |
| Documentation: | Amount, after tax, of accumulated unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) with allowance for credit loss. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | As Of (instant) |
| Balance type: | Credit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:AociDebtSecuritiesAvailableForSaleWithAllowanceForCreditLossCumulativeGainLossAfterTax |
| Label | Role | Language |
| AOCI, Debt Securities, Available-for-sale with Allowance for Credit Loss, Cumulative Gain (Loss), after Tax | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 326 30 45 2 | http://www.xbrl.org/2003/role/disclosureRef | 326 |