Investments - Schedule of Carrying Value for Limited Partnership Interests (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Debt and Equity Securities, FV-NI [Line Items]
Limited partnership interests	$ 8,380	$ 8,114
EMA
Debt and Equity Securities, FV-NI [Line Items]
Limited partnership interests	7,215	6,868
Fair Value
Debt and Equity Securities, FV-NI [Line Items]
Limited partnership interests	1,165	1,246
Private equity
Debt and Equity Securities, FV-NI [Line Items]
Limited partnership interests	7,154	6,589
Private equity | EMA
Debt and Equity Securities, FV-NI [Line Items]
Limited partnership interests	6,015	5,372
Private equity | Fair Value
Debt and Equity Securities, FV-NI [Line Items]
Limited partnership interests	1,139	1,217
Real estate
Debt and Equity Securities, FV-NI [Line Items]
Limited partnership interests	1,085	1,042
Real estate | EMA
Debt and Equity Securities, FV-NI [Line Items]
Limited partnership interests	1,059	1,013
Real estate | Fair Value
Debt and Equity Securities, FV-NI [Line Items]
Limited partnership interests	26	29
Other
Debt and Equity Securities, FV-NI [Line Items]
Limited partnership interests	141	483
Other | EMA
Debt and Equity Securities, FV-NI [Line Items]
Limited partnership interests	141	483
Other | Fair Value
Debt and Equity Securities, FV-NI [Line Items]
Limited partnership interests	$ 0	$ 0