cm:Concept: us-gaap:FinancialInstrumentsOwnedCorporateEquitiesAtFairValue
| Financial Instruments, Owned, Corporate Equities, at Fair Value |
| us-gaap:FinancialInstrumentsOwnedCorporateEquitiesAtFairValue |
| The fair value as of the balance sheet date of firm holdings in corporate stocks (common and preferred), stock options, warrants and any other financial instrument which represents, or provides the ability to obtain, ownership rights in a corporation. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:FinancialInstrumentsOwnedCorporateEquitiesAtFairValue |