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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, 2024 USD ($) contract | Dec. 31, 2023 USD ($) contract
Guarantor Obligations [Line Items] |  |
Contracts outstanding | contract | 14,725 | 14,485
Remaining weighted average contract period (in years) | 10 years 6 months | 11 years 1 month 6 days
Principal | $ 112,216.7 | $ 109,673.8
Interest | 57,545.8 | 56,012.2
Total debt service outstanding | 169,762.5 | 165,686.0
Total gross unearned insurance premiums | $ 328.5 | $ 325.8

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