Fair Value - Reconciliation of the Beginning and Ending Balances of Assets Measured at Fair Value on a Recurring Basis Using Level III Inputs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 872	$ 665	$ 581
Recognized in net income	(6)	(5)	(14)
Recognized in accumulated other comprehensive income	$ 29	$ 12	$ 9
Fair Value, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement Of Other Comprehensive Income, Extensible List, Not Disclosed Flag	false	false	false
Purchases	$ 613	$ 171	$ 244
Sales	(70)	(34)	(126)
Settlements	(60)	(5)	(21)
Transfers into Level III	6	92	14
Transfers out of Level III	(36)	(24)	(22)
Ending balance	1,348	872	665
Change in unrealized losses included in net income related to assets still held	(10)	(5)	(6)
Corporate securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	43	46	137
Recognized in net income	3	1	(10)
Recognized in accumulated other comprehensive income	12	0	6
Purchases	384	26	38
Sales	0	(5)	(88)
Settlements	(7)	(4)	(21)
Transfers into Level III	1	0	6
Transfers out of Level III	(26)	(21)	(22)
Ending balance	410	43	46
Change in unrealized losses included in net income related to assets still held	0	0	0
Residential mortgage-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	10	2	0
Recognized in net income	0	0	0
Recognized in accumulated other comprehensive income	0	0	0
Purchases	13	10	0
Sales	0	(2)	0
Settlements	0	0	0
Transfers into Level III	4	0	2
Transfers out of Level III	(10)	0	0
Ending balance	17	10	2
Change in unrealized losses included in net income related to assets still held	0	0	0
Other asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	747	539	356
Recognized in net income	0	0	0
Recognized in accumulated other comprehensive income	17	12	3
Purchases	162	118	191
Sales	(8)	(10)	(17)
Settlements	(53)	(1)	0
Transfers into Level III	1	92	6
Transfers out of Level III	0	(3)	0
Ending balance	866	747	539
Change in unrealized losses included in net income related to assets still held	0	0	0
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	72	78	88
Recognized in net income	(9)	(6)	(4)
Recognized in accumulated other comprehensive income	0	0	0
Purchases	54	17	15
Sales	(62)	(17)	(21)
Settlements	0	0	0
Transfers into Level III	0	0	0
Transfers out of Level III	0	0	0
Ending balance	55	72	78
Change in unrealized losses included in net income related to assets still held	$ (10)	$ (5)	$ (6)