cm:Concept: us-gaap:FinancialGuaranteeInsuranceContractsRiskManagementActivitiesDescriptionOfCategories
| Financial Guarantee Insurance Contracts, Risk Management Activities, Description of Categories |
| us-gaap:FinancialGuaranteeInsuranceContractsRiskManagementActivitiesDescriptionOfCategories |
| This element represents a description of each grouping or category used by the entity's management to track and monitor deteriorating insured financial obligations related to financial guarantee insurance contracts. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:FinancialGuaranteeInsuranceContractsRiskManagementActivitiesDescriptionOfCategories |