| Standard label: | Fair Value, Option, Loans Held as Assets, 90 Days or More Past Due, Aggregate Difference |
| Name: | us-gaap:FairValueOptionLoansHeldAsAssets90DaysOrMorePastDueAggregateDifference |
| Documentation: | For loans held as assets for which the fair value option has been elected, this item represents the difference between the aggregate fair value and the aggregate unpaid principal balance of those loans that are 90 days or more past due. |
| 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:FairValueOptionLoansHeldAsAssets90DaysOrMorePastDueAggregateDifference |
| Label | Role | Language |
| Fair Value, Option, Loans Held as Assets, 90 Days or More Past Due, Aggregate Difference | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 825 10 50 28 (e)(3) | http://fasb.org/us-gaap/role/ref/legacyRef | 825 |
| Part Of Roll Up: |
| us-gaap:FairValueOptionLoansHeldAsAssetsAggregateDifference |