Fair Value of Financial Instruments - Changes in Unrealized Gains (Losses) Included in OCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring Basis Level 3 Activity [Line Items]
Unrealized gains (losses) included in OCI, net	$ (9)	$ 24
Corporate bonds
Fair Value Assets And Liabilities Measured On Recurring Basis Level 3 Activity [Line Items]
Unrealized gains (losses) included in OCI, net	(11)	13
State and municipal bonds
Fair Value Assets And Liabilities Measured On Recurring Basis Level 3 Activity [Line Items]
Unrealized gains (losses) included in OCI, net	0	1
ABS
Fair Value Assets And Liabilities Measured On Recurring Basis Level 3 Activity [Line Items]
Unrealized gains (losses) included in OCI, net	(1)	8
Hybrid and redeemable preferred securities
Fair Value Assets And Liabilities Measured On Recurring Basis Level 3 Activity [Line Items]
Unrealized gains (losses) included in OCI, net	2	0
Mortgage loans on real estate
Fair Value Assets And Liabilities Measured On Recurring Basis Level 3 Activity [Line Items]
Unrealized gains (losses) included in OCI, net	$ 1	$ 2