| Standard label: | Financial Guarantee Insurance Contracts, Premiums Receivable, Increase (Decrease), Change in Period of Contract |
| Name: | us-gaap:FinancialGuaranteeInsuranceContractsPremiumsReceivableAdjustmentChangeInPeriodOfContract |
| Documentation: | Amount of increase (decrease) in the premium receivable on financial guarantee insurance contracts from changes in the period of the contract. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | For Period (duration) |
| Balance type: | Debit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:FinancialGuaranteeInsuranceContractsPremiumsReceivableAdjustmentChangeInPeriodOfContract |
| Label | Role | Language |
| Financial Guarantee Insurance Contracts, Premiums Receivable, Increase (Decrease), Change in Period of Contract | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 944 310 50 3 (c)(4)(i) | http://fasb.org/us-gaap/role/ref/legacyRef | 944 |