cm:Concept: us-gaap:SecuritiesLoanedOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection
| Securities Loaned, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election |
| us-gaap:SecuritiesLoanedOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection |
| Amount, after effects of master netting arrangements, deduction of liabilities not subject to a master netting arrangement and elected not to be offset, of securities loaned to entities in exchange for collateral, offset against a right to receive collateral. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:SecuritiesLoanedOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection |