cm:Concept: us-gaap:PledgedAssetsSeparatelyReportedNonsecuritizedInvestmentsPledgedAsCollateralAtFairValue
| Pledged Assets Separately Reported, Nonsecuritized Investments Pledged as Collateral, at Fair Value |
| us-gaap:PledgedAssetsSeparatelyReportedNonsecuritizedInvestmentsPledgedAsCollateralAtFairValue |
| The fair value, as of the date of each statement of financial position presented, of investments which are not evidenced by ownership of securities, such as interests in partnerships or other forms of unincorporated entities, which are owned but transferred to serve as collateral for the payment of the related debt obligation, and that is reclassified and separately reported in the statement of financial position because the transferee has the right by contract or custom to sell or re-pledge such ownership interests. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:PledgedAssetsSeparatelyReportedNonsecuritizedInvestmentsPledgedAsCollateralAtFairValue |