Reinsurance (Funds Withheld Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Reinsurance Funds Withheld Assets [Line Items]
Funds withheld at interest	$ 5,328	$ 5,436
Fixed Maturities [Member]
Reinsurance Funds Withheld Assets [Line Items]
Funds withheld at interest	2,636	2,615
Equity securities
Reinsurance Funds Withheld Assets [Line Items]
Funds withheld at interest	2	2
Mortgage Loans on Real Estate [Member]
Reinsurance Funds Withheld Assets [Line Items]
Funds withheld at interest	450	451
Funds withheld at interest
Reinsurance Funds Withheld Assets [Line Items]
Funds withheld at interest	1,444	1,466
Partnership
Reinsurance Funds Withheld Assets [Line Items]
Funds withheld at interest	53	54
Short-term Investments [Member]
Reinsurance Funds Withheld Assets [Line Items]
Funds withheld at interest	75	89
Accrued Income Receivable
Reinsurance Funds Withheld Assets [Line Items]
Funds withheld at interest	34	31
Other Assets
Reinsurance Funds Withheld Assets [Line Items]
Funds withheld at interest	1	0
Assets
Reinsurance Funds Withheld Assets [Line Items]
Funds withheld at interest	$ 4,695	$ 4,708