| Standard label: | Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Portion in Other Comprehensive Loss, before Tax, Including Portion Attributable to Noncontrolling Interest |
| Name: | us-gaap:OtherThanTemporaryImpairmentLossesInvestmentsPortionInOtherComprehensiveIncomeLossBeforeTaxIncludingPortionAttributableToNoncontrollingInterestAvailableforsaleSecurities |
| Documentation: | Amount, before tax, of other-than-temporary impairment (OTTI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), recognized in other comprehensive income (OCI). |
| 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:OtherThanTemporaryImpairmentLossesInvestmentsPortionInOtherComprehensiveIncomeLossBeforeTaxIncludingPortionAttributableToNoncontrollingInterestAvailableforsaleSecurities |
| Label | Role | Language |
| Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Portion in Other Comprehensive Loss, before Tax, Including Portion Attributable to Noncontrolling Interest | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 220 10 45 10A (g) | http://fasb.org/us-gaap/role/ref/legacyRef | 220 |
| FASB Accounting Standards Codification 320 10 45 8A | http://www.xbrl.org/2003/role/disclosureRef | 320 |