| Standard label: | Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Other, Third Party Guarantees, Amount |
| Name: | us-gaap:AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureOtherThirdPartyGuaranteesAmount |
| Documentation: | Amount of third party guarantees against loss of value in the underlying assets related to available-for-sale security in an unrealized loss position and for which other-than-temporary impairments (OTTI) have not been recognized. |
| 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:AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureOtherThirdPartyGuaranteesAmount |
| Label | Role | Language |
| Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Other, Third Party Guarantees, Amount | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 320 10 50 6 | http://fasb.org/us-gaap/role/ref/legacyRef | 320 |