Investments - Fair Value of Trading Securities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	$ 2,359	$ 3,498
Corporate bonds
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	1,653	2,248
State and municipal bonds
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	21	21
Foreign government bonds
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	46	49
RMBS
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	62	99
CMBS
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	104	137
ABS
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	455	919
Hybrid and redeemable preferred securities
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	$ 18	$ 25