cm:Table: us-gaap:ScheduleOfAssetsAndAssociatedLiabilitiesAccountedForAsSecuredBorrowingsTable
| Schedule of Assets and Associated Liabilities Accounted for as Secured Borrowings [Table] |
| us-gaap:ScheduleOfAssetsAndAssociatedLiabilitiesAccountedForAsSecuredBorrowingsTable |
| Information about the carrying amount and classification of assets and liabilities recognized in the transferor's statement of financial position at the end of each period presented. |
| cm:Table |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:ScheduleOfAssetsAndAssociatedLiabilitiesAccountedForAsSecuredBorrowingsTable |