cm:Concept: us-gaap:DerivativeLiabilitySecuritiesSoldUnderAgreementsToResellSecuritiesLoanedNotSubjectToMasterNettingArrangementDeduction
| Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Not Subject to Master Netting Arrangement Deduction |
| us-gaap:DerivativeLiabilitySecuritiesSoldUnderAgreementsToResellSecuritiesLoanedNotSubjectToMasterNettingArrangementDeduction |
| Amount of derivative liabilities, securities sold under agreements to repurchase and securities loaned, not subject to a master netting arrangement, deducted from derivative liabilities, securities sold under agreements to repurchase and securities loaned. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:DerivativeLiabilitySecuritiesSoldUnderAgreementsToResellSecuritiesLoanedNotSubjectToMasterNettingArrangementDeduction |