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