cm:Concept: us-gaap:TransferOfFinancialAssetsAccountedForAsSalesCashProceedsReceivedForAssetsDerecognizedAmount
| Transfer of Financial Assets Accounted for as Sales, Cash Proceeds Received for Assets Derecognized, Amount |
| us-gaap:TransferOfFinancialAssetsAccountedForAsSalesCashProceedsReceivedForAssetsDerecognizedAmount |
| Amount, before counterparty netting, of cash proceeds received in transfers of derecognized financial assets from transactions which comprise an initial transfer and an agreement entered into in contemplation of the initial transfer resulting in retention of substantially all of the exposure to the economic return throughout the term of the transaction. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:TransferOfFinancialAssetsAccountedForAsSalesCashProceedsReceivedForAssetsDerecognizedAmount |