cm:Axis: us-gaap:AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis
| Industry of Counterparty, Type [Axis] |
| us-gaap:AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis |
| Information by industry of counterparty. A counterparty is the other party that participates in a financial transaction. |
| cm:Axis |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis |