Long-term Debt- Schedule of Fair Value and Carrying Value (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Total Carrying Value
Debt Instrument [Line Items]
Long-term debt	$ 19,813	$ 18,281
Fair Value
Debt Instrument [Line Items]
Long-term debt	19,457	16,969
Unsecured Notes | Total Carrying Value
Debt Instrument [Line Items]
Long-term debt	19,641	18,109
Unsecured Notes | Fair Value
Debt Instrument [Line Items]
Long-term debt	19,273	16,782
Junior Subordinated Debt | Total Carrying Value
Debt Instrument [Line Items]
Long-term debt	172	172
Junior Subordinated Debt | Fair Value
Debt Instrument [Line Items]
Long-term debt	$ 184	$ 187