cm:Table: us-gaap:SecuritizationFinancialAssetForWhichTransferIsAccountedAsSaleTable
| Schedule of Securitization or Asset-backed Financing Arrangements, Financial Asset for which Transfer is Accounted as Sale [Table] |
| us-gaap:SecuritizationFinancialAssetForWhichTransferIsAccountedAsSaleTable |
| The gains or losses by type of financial asset in a securitization, asset-backed financing arrangement, or similar transfer recognized when a transfer is accounted for as a sale. |
| cm:Table |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:SecuritizationFinancialAssetForWhichTransferIsAccountedAsSaleTable |