Investments - Assets Pledged as Collateral (Details) - Asset Pledged as Collateral - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	$ 5,732	$ 4,955
Fixed maturity AFS securities
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	3,642	3,578
Trading securities
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	14	14
Equity securities
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	4	10
Mortgage loans on real estate
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	1,666	1,217
Other investments
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	50	71
Cash and invested cash
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	$ 356	$ 65