cm:Concept: us-gaap:SecuritiesBorrowedNotSubjectToMasterNettingArrangementDeduction
| Securities Borrowed, Not Subject to Master Netting Arrangement Deduction |
| us-gaap:SecuritiesBorrowedNotSubjectToMasterNettingArrangementDeduction |
| Amount of securities borrowed from entities in exchange for collateral, not subject to a master netting arrangement, deducted from securities borrowed. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:SecuritiesBorrowedNotSubjectToMasterNettingArrangementDeduction |