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, 2022	Dec. 31, 2021
Variable Interest Entities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 2,005
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	73	$ 141
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	43	16
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Loans Unpaid Principal Balance	2,257	2,363
Long Term Debt Unpaid Principal Balance	3,439	3,579
Variable Interest Entity, Primary Beneficiary [Member] | Municipal Bonds [Member]
Variable Interest Entities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	103	106
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	$ 17	$ 29