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Business and Basis of Presentation (Details) $ in Millions |  |  | 1 Months Ended | 3 Months Ended | 6 Months Ended
--- | --- | --- | --- | --- | ---
Aug. 05, 2024 USD ($) | Jul. 01, 2023 rISK | May 31, 2024 USD ($) | Jun. 30, 2024 USD ($) Company | Jun. 30, 2023 USD ($) | Jun. 30, 2023 USD ($)
Long-Lived Assets Held-for-sale [Line Items] |  |  |  |  |  |
Number of holding companies with outstanding public debt | Company |  |  |  | 2 |  |
Assured Guaranty Municipal Corp. |  |  |  |  |  |
Long-Lived Assets Held-for-sale [Line Items] |  |  |  |  |  |
Stock redeemed or during period |  |  | $ 100 |  |  |
Subsequent Event | AGC |  |  |  |  |  |
Long-Lived Assets Held-for-sale [Line Items] |  |  |  |  |  |
Stock redeemed or during period | $ 300 |  |  |  |  |
Proceeds in exchange for redemption of common stock | $ 172 |  |  |  |  |
Consolidated Investment Vehicles |  |  |  |  |  |
Long-Lived Assets Held-for-sale [Line Items] |  |  |  |  |  |
Number of remaining CIVs | rISK |  | 3 |  |  |  |
Disposal Group, Held-for-sale, Not Discontinued Operations |  |  |  |  |  |
Long-Lived Assets Held-for-sale [Line Items] |  |  |  |  |  |
Assets held for sale |  |  |  | $ 28 |  |
Liabilities held for sale |  |  |  | $ 2 |  |
Disposal Group, Held-for-sale, Not Discontinued Operations | Sound Point Agreement |  |  |  |  |  |
Long-Lived Assets Held-for-sale [Line Items] |  |  |  |  |  |
Participation percentage |  | 30.00% |  |  |  |
Term to make new investments |  |  |  | 2 years |  |
Term to reinvest all returns of capital |  | 15 years |  |  |  |
Expenses recognized |  |  |  |  | $ 24 | $ 31

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