cm:Concept: us-gaap:LiabilityNetForClaimsAndClaimsAdjustmentExpenseFinancialGuaranteeInsuranceContracts
| Liability for Claims and Claims Adjustment Expense, Financial Guarantee Insurance Contracts |
| us-gaap:LiabilityNetForClaimsAndClaimsAdjustmentExpenseFinancialGuaranteeInsuranceContracts |
| The amount needed to reflect the estimated ultimate cost of settling claims relating to financial default insured events that have occurred on or before a particular date (ordinarily, the balance sheet date) and the amount needed to provide for the estimated ultimate cost required to investigate and settle claims relating to insured events that have occurred on or before a particular date (ordinarily, the balance sheet date), whether or not reported to the insurer at that date. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:LiabilityNetForClaimsAndClaimsAdjustmentExpenseFinancialGuaranteeInsuranceContracts |