| Standard label: | Financial Guarantee Insurance Contracts, Premium Receivable, Proceeds from Premiums Received |
| Name: | us-gaap:FinancialGuaranteeInsuranceContractsPremiumReceivableProceedsFromPremiumsReceived |
| Documentation: | Amount of cash inflow from premiums received for premium receivable on financial guarantee insurance contracts. |
| 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:FinancialGuaranteeInsuranceContractsPremiumReceivableProceedsFromPremiumsReceived |
| Label | Role | Language |
| Financial Guarantee Insurance Contracts, Premium Receivable, Proceeds from Premiums Received | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 230 10 45 17 (f) | http://www.xbrl.org/2009/role/commonPracticeRef | 230 |
| FASB Accounting Standards Codification 944 310 50 3 (c)(2) | http://www.xbrl.org/2003/role/disclosureRef | 944 |