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Financial Guaranty Variable Interest Entities and Consolidated Investment Vehicles - Contractual Maturity (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Estimated Fair Value
Estimated Fair Value	$ 6,869	$ 7,119
Variable Interest Entity, Primary Beneficiary | Financial Guaranty Variable Interest Entities | Puerto Rico Trusts
Amortized Cost
Due within one year	1
Due after one year through five years	6
Due after five years through 10 years	42
Due after 10 years	155
Total	204
Estimated Fair Value
Due within one year	1
Due after one year through five years	6
Due after five years through 10 years	43
Due after 10 years	161
Estimated Fair Value	$ 211	$ 204

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