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Municipal Bond Guarantee Insurance - Schedule of Municipal Bond Guarantee Insured Obligations (Details) - BAM $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2023 USD ($) Contract | Dec. 31, 2022 USD ($) Contract
Guarantor Obligations [Line Items] |  |
Contracts outstanding | Contract | 13,607 | 13,382
Remaining weighted average contract period (in years) | 10 years 9 months 18 days | 10 years 9 months 18 days
Principal | $ 101,785.7 | $ 99,996.9
Interest | 49,801.9 | 48,880.6
Total debt service outstanding | 151,587.6 | 148,877.5
Total gross unearned insurance premiums | $ 299.8 | $ 298.3

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