Investments - Assets Pledged as Collateral (Details) - Asset Pledged as Collateral - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	$ 4,883	$ 5,432
Fixed maturity AFS securities
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	2,297	1,736
Trading securities
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	24	23
Equity securities
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	3	12
Mortgage loans on real estate
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	2,486	3,530
Other investments – short-term investments
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	20	21
Cash and invested cash
Financial Instruments Owned and Pledged as Collateral [Line Items]
Total assets pledged as collateral	$ 53	$ 110