cm:Concept: us-gaap:SecuritizationFinancialAssetForWhichTransferIsAccountedAsSaleGainLossOnSale
| Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale, Gain (Loss) on Sale |
| us-gaap:SecuritizationFinancialAssetForWhichTransferIsAccountedAsSaleGainLossOnSale |
| Reflects, by transferred financial asset type, the amount of sales proceeds in excess of or deficient from the sum of the carrying amounts of transferred financial assets plus transaction costs, including those transactions in which the seller/transferor has continuing involvement with the financial assets that have been transferred. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:SecuritizationFinancialAssetForWhichTransferIsAccountedAsSaleGainLossOnSale |