| Standard label: | Available-for-sale Securities, Transfers to Trading, Gains (Losses) |
| Name: | us-gaap:AvailableForSaleSecuritiesTransfersToTradingGainsLossesNet |
| Documentation: | This item represents the difference between the gross amount of gains (losses) included in earnings for transfers of securities from the available-for-sale category into the trading category. Such net gain (loss) included in earnings represents the net unrealized gain (loss) which had been included in other comprehensive income and is associated with the securities transferred from the available-for-sale category to the trading category. |
| 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:AvailableForSaleSecuritiesTransfersToTradingGainsLossesNet |
| Label | Role | Language |
| Available-for-sale Securities, Transfers to Trading, Gains (Losses) | http://www.xbrl.org/2003/role/label | en-US |
| Available-for-sale Securities, Transfers to Trading, Gains (Losses), Total | http://www.xbrl.org/2003/role/totalLabel | en-US |
| Reference | Role | Topic |