cm:Concept: us-gaap:SecuritiesLoanedGrossIncludingNotSubjectToMasterNettingArrangement
| Securities Loaned, Gross Including Not Subject to Master Netting Arrangement |
| us-gaap:SecuritiesLoanedGrossIncludingNotSubjectToMasterNettingArrangement |
| Amount, before effects of master netting arrangements, of securities loaned to entities in exchange for collateral. Includes liabilities not subject to a master netting arrangement and elected not to be offset. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:SecuritiesLoanedGrossIncludingNotSubjectToMasterNettingArrangement |