Fair Value of Financial Instruments - Components of the Transfers In and Out of Level 3 (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	$ 20	$ 54	$ 92	$ 266
Transfers Out of Level 3	(210)	(210)	(510)	(562)
Total	(190)	(156)	(418)	(296)
Corporate bonds
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	0	36	22	195
Transfers Out of Level 3	(7)	(79)	(143)	(198)
Total	(7)	(43)	(121)	(3)
RMBS
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	0	12	0	12
Transfers Out of Level 3	(5)	(5)	(5)	(5)
Total	(5)	7	(5)	7
CMBS
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	0	0	0	4
Transfers Out of Level 3	(16)	0	(16)	0
Total	(16)	0	(16)	4
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			(5)	0
Total			(5)	0
ABS
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	0	0	50	2
Transfers Out of Level 3	(178)	(113)	(286)	(346)
Total	(178)	(113)	(236)	(344)
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	16
Transfers Out of Level 3	0	(13)	0	(13)
Total	10	(13)	10	3
Trading securities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3	0	6	0	6
Transfers Out of Level 3	0	0	0	0
Total	0	6	0	6
Equity securities
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	(4)	0	(4)	0
Total	(4)	0	(4)	0
Derivative investments
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net [Abstract]
Transfers Into Level 3			0	31
Transfers Out of Level 3			(51)	0
Total			(51)	31
Other investments
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	0	0
Total	$ 10	$ 0	$ 10	$ 0