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Financial Guaranty Variable Interest Entities and Consolidated Investment Vehicles - New Recovery Bonds (Details) - USD ($) $ in Millions | Sep. 30, 2023 | Aug. 31, 2023 | Dec. 31, 2022
--- | --- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |  |
Amortized Cost | $ 6,971 |  | $ 7,707
Gross Unrealized Gains | 30 |  | 65
Gross unrealized loss | (648) |  | (588)
Estimated Fair Value | 6,267 |  | 7,119
Variable Interest Entity, Primary Beneficiary | Financial Guaranty Variable Interest Entities | Puerto Rico Trusts |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Amortized Cost | 136 |  | 204
Gross Unrealized Gains | 10 |  | 4
Gross unrealized loss | 0 |  | (4)
Estimated Fair Value | $ 146 | $ 73 | $ 204

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