| Standard label: | Trading Activity, by Type [Domain] |
| Name: | us-gaap:TradingActivityByTypeDomain |
| Documentation: | Gains and losses on trading activities (including both derivative and nonderivative instruments) recognized in the statement of financial performance, separately by major types of items (such as fixed income/interest rates, foreign exchange, equity, commodity, and credit). |
| Object type: | cm:Member |
| Data type: | [Member] (nonnum:domainItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | true |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:TradingActivityByTypeDomain |
| Label | Role | Language |
| Trading Activity, by Type [Domain] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 815 10 50 4F (a) | http://fasb.org/us-gaap/role/ref/legacyRef | 815 |