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Special Purpose Entities, Including Variable Interest Entities - Summary of Fair Value of Fixed Income Securities, by Asset-Type, Held by Consolidated Variable Interest Entities (Details) - USD ($) $ in Millions | Mar. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Variable Interest Entities [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | $ 2,135 | $ 2,197
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 37 | 40
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | 75 | 71
Variable Interest Entity, Primary Beneficiary [Member] |  |
Variable Interest Entities [Line Items] |  |
Loans Unpaid Principal Balance | 1,730 | 1,787
Long Term Debt Unpaid Principal Balance | 2,889 | 2,952
Variable Interest Entity, Primary Beneficiary [Member] | Municipal Bonds [Member] |  |
Variable Interest Entities [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 85 | 88
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 7 | 7
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | $ 0 | $ 0

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