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	$ 5,649	$ 4,901
Fixed maturity AFS securities
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	3,639	3,577
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 – short-term investments
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	5	20
Cash and invested cash
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	$ 321	$ 63