Fair Value of Financial Instruments - Components of the Transfers In and Out of Level 3 (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	$ 174	$ 18	$ 270	$ 72
Transfers Out of Level 3	(67)	(177)	(77)	(300)
Total	107	(159)	193	(228)
Corporate bonds
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	90	0	112	22
Transfers Out of Level 3	(1)	(92)	(1)	(136)
Total	89	(92)	111	(114)
RMBS
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	0	0	0	0
Transfers Out of Level 3	(7)	0	(7)	0
Total	(7)	0	(7)	0
CMBS
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	0	0	0	0
Transfers Out of Level 3	(7)	0	(7)	0
Total	(7)	0	(7)	0
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	13	18	70	50
Transfers Out of Level 3	(52)	(85)	(52)	(108)
Total	(39)	(67)	18	(58)
Hybrid and redeemable preferred securities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	10	0	10	0
Transfers Out of Level 3	0	0	(10)	0
Total	10	0	0	0
Trading securities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	7	0	24	0
Transfers Out of Level 3	0	0	0	0
Total	7	0	24	0
Equity securities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	54	0	54	0
Transfers Out of Level 3	0	0	0	0
Total	$ 54	$ 0	54	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)