Fair Value of Financial Instruments - Components of the Transfers In and Out of Level 3 (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	$ 96	$ 53
Transfers Out of Level 3	(10)	(123)
Total	86	(70)
Corporate bonds
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	22	22
Transfers Out of Level 3	0	(44)
Total	22	(22)
State and municipal bonds
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	0	0
Transfers Out of Level 3	0	(5)
Total	0	(5)
ABS
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	57	31
Transfers Out of Level 3	0	(23)
Total	57	8
Hybrid and redeemable preferred securities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	0	0
Transfers Out of Level 3	(10)	0
Total	(10)	0
Trading securities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	17	0
Transfers Out of Level 3	0	0
Total	17	0
Derivative investments
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	0	0
Transfers Out of Level 3	0	(51)
Total	$ 0	$ (51)