Investments - Fair Value of Trading Securities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	$ 2,005	$ 2,321
Corporate bonds
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	1,390	1,615
State and municipal bonds
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	13	21
Foreign government bonds
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	41	46
RMBS
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	63	62
CMBS
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	108	104
ABS
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	371	455
Hybrid and redeemable preferred securities
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	$ 19	$ 18