| Standard label: | Net Realized and Unrealized Gain (Loss) on Trading Securities |
| Name: | us-gaap:NetRealizedOrUnrealizedGainLossOnTradingSecurities |
| Documentation: | The sum of the realized and unrealized net gain (loss) on trading securities during the period. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | For Period (duration) |
| Balance type: | Credit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:NetRealizedOrUnrealizedGainLossOnTradingSecurities |
| Label | Role | Language |
| Net Realized and Unrealized Gain (Loss) on Trading Securities | http://www.xbrl.org/2003/role/label | en-US |
| Net Realized and Unrealized Gain (Loss) on Trading Securities, Total | http://www.xbrl.org/2003/role/totalLabel | en-US |
| Reference | Role | Topic |