Investments - Investments - VIEs (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Schedule of Investments [Line Items]
Variable Interest Entity, Primary Beneficiary, Maximum Loss Exposure, Amount	$ 0		$ 0
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	3,000		3,000
Amortization Method Qualified Affordable Housing Project Investments, Amortization	1	$ 1
Affordable Housing Tax Credits and Other Tax Benefits, Amount	2	$ 1
Other Assets	1,953		1,754
Qualified Affordable Housing Project Investments, Commitment	177		180
Variable Interest Entity, Not Primary Beneficiary [Member]
Schedule of Investments [Line Items]
Other Assets	22		20
Variable Interest Entity, Not Primary Beneficiary [Member]
Schedule of Investments [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Commitments	$ 1,700		$ 1,700