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	Jun. 30, 2024	Dec. 31, 2023
Variable Interest Entities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 2,078	$ 2,197
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	45	40
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	78	71
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Loans Unpaid Principal Balance	1,692	1,787
Long Term Debt Unpaid Principal Balance	2,854	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	6	7
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 0	$ 0