Investments - Schedule of Amortized Cost, Gross Unrealized Gains (Losses), Allowance for Credit Losses and Fair Value of Our Fixed Maturity Securities Classified as Available-For-Sale (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Schedule of Investments [Line Items]
Amortized cost	$ 48,150	$ 48,720
Gross unrealized gains	871	452
Gross unrealized losses	(3,236)	(4,260)
Allowance for credit losses	(23)	(10)	$ (7)	$ 0
Fixed maturity securities, fair value	45,762	44,902
U.S. government, agencies and government-sponsored enterprises
Schedule of Investments [Line Items]
Amortized cost	3,999	3,847
Gross unrealized gains	66	24
Gross unrealized losses	(364)	(378)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	3,701	3,493
State and political subdivisions
Schedule of Investments [Line Items]
Amortized cost	2,356	2,452
Gross unrealized gains	13	8
Gross unrealized losses	(255)	(311)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	2,114	2,149
Non-U.S. government
Schedule of Investments [Line Items]
Amortized cost	1,257	1,021
Gross unrealized gains	36	5
Gross unrealized losses	(76)	(117)
Allowance for credit losses	(2)	0
Fixed maturity securities, fair value	1,215	909
U.S. corporate
Schedule of Investments [Line Items]
Amortized cost	28,356	28,928
Gross unrealized gains	572	328
Gross unrealized losses	(1,874)	(2,481)
Allowance for credit losses	(8)	(4)	0	0
Fixed maturity securities, fair value	27,046	26,771
U.S. corporate | Utilities
Schedule of Investments [Line Items]
Amortized cost	4,798	4,685
Gross unrealized gains	95	47
Gross unrealized losses	(375)	(450)
Allowance for credit losses	(3)	0
Fixed maturity securities, fair value	4,515	4,282
U.S. corporate | Energy
Schedule of Investments [Line Items]
Amortized cost	2,506	2,444
Gross unrealized gains	69	38
Gross unrealized losses	(123)	(170)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	2,452	2,312
U.S. corporate | Finance and insurance
Schedule of Investments [Line Items]
Amortized cost	7,435	7,533
Gross unrealized gains	109	57
Gross unrealized losses	(487)	(675)
Allowance for credit losses	0	(4)
Fixed maturity securities, fair value	7,057	6,911
U.S. corporate | Consumer—non-cyclical
Schedule of Investments [Line Items]
Amortized cost	4,591	4,728
Gross unrealized gains	98	51
Gross unrealized losses	(279)	(392)
Allowance for credit losses	(4)	0
Fixed maturity securities, fair value	4,406	4,387
U.S. corporate | Technology and communications
Schedule of Investments [Line Items]
Amortized cost	2,947	2,992
Gross unrealized gains	58	42
Gross unrealized losses	(256)	(311)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	2,749	2,723
U.S. corporate | Industrial
Schedule of Investments [Line Items]
Amortized cost	1,030	1,166
Gross unrealized gains	14	11
Gross unrealized losses	(89)	(105)
Allowance for credit losses	(1)	0
Fixed maturity securities, fair value	954	1,072
U.S. corporate | Capital goods
Schedule of Investments [Line Items]
Amortized cost	2,359	2,360
Gross unrealized gains	65	37
Gross unrealized losses	(105)	(154)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	2,319	2,243
U.S. corporate | Consumer—cyclical
Schedule of Investments [Line Items]
Amortized cost	1,295	1,602
Gross unrealized gains	23	13
Gross unrealized losses	(69)	(118)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	1,249	1,497
U.S. corporate | Transportation
Schedule of Investments [Line Items]
Amortized cost	1,115	1,135
Gross unrealized gains	37	30
Gross unrealized losses	(77)	(91)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	1,075	1,074
U.S. corporate | Other
Schedule of Investments [Line Items]
Amortized cost	280	283
Gross unrealized gains	4	2
Gross unrealized losses	(14)	(15)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	270	270
Non-U.S. corporate
Schedule of Investments [Line Items]
Amortized cost	7,430	7,830
Gross unrealized gains	149	73
Gross unrealized losses	(379)	(573)
Allowance for credit losses	(9)	(3)	0
Fixed maturity securities, fair value	7,191	7,327
Non-U.S. corporate | Utilities
Schedule of Investments [Line Items]
Amortized cost	672	750
Gross unrealized gains	4	1
Gross unrealized losses	(36)	(55)
Allowance for credit losses	(3)	(3)
Fixed maturity securities, fair value	637	693
Non-U.S. corporate | Energy
Schedule of Investments [Line Items]
Amortized cost	957	1,046
Gross unrealized gains	27	16
Gross unrealized losses	(36)	(56)
Allowance for credit losses	(4)	0
Fixed maturity securities, fair value	944	1,006
Non-U.S. corporate | Finance and insurance
Schedule of Investments [Line Items]
Amortized cost	1,751	1,877
Gross unrealized gains	43	20
Gross unrealized losses	(75)	(123)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	1,719	1,774
Non-U.S. corporate | Consumer—non-cyclical
Schedule of Investments [Line Items]
Amortized cost	615	632
Gross unrealized gains	6	3
Gross unrealized losses	(64)	(79)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	557	556
Non-U.S. corporate | Technology and communications
Schedule of Investments [Line Items]
Amortized cost	743	801
Gross unrealized gains	9	5
Gross unrealized losses	(63)	(80)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	689	726
Non-U.S. corporate | Industrial
Schedule of Investments [Line Items]
Amortized cost	769	805
Gross unrealized gains	19	7
Gross unrealized losses	(27)	(46)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	761	766
Non-U.S. corporate | Capital goods
Schedule of Investments [Line Items]
Amortized cost	710	633
Gross unrealized gains	11	4
Gross unrealized losses	(29)	(46)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	692	591
Non-U.S. corporate | Consumer—cyclical
Schedule of Investments [Line Items]
Amortized cost	255	245
Gross unrealized gains	3	1
Gross unrealized losses	(8)	(16)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	250	230
Non-U.S. corporate | Transportation
Schedule of Investments [Line Items]
Amortized cost	491	454
Gross unrealized gains	15	11
Gross unrealized losses	(21)	(29)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	485	436
Non-U.S. corporate | Other
Schedule of Investments [Line Items]
Amortized cost	467	587
Gross unrealized gains	12	5
Gross unrealized losses	(20)	(43)
Allowance for credit losses	(2)	0
Fixed maturity securities, fair value	457	549
Residential mortgage-backed
Schedule of Investments [Line Items]
Amortized cost	1,115	862
Gross unrealized gains	19	4
Gross unrealized losses	(34)	(55)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	1,100	811
Commercial mortgage-backed
Schedule of Investments [Line Items]
Amortized cost	1,536	1,591
Gross unrealized gains	3	1
Gross unrealized losses	(226)	(288)
Allowance for credit losses	(4)	(3)	$ (7)	$ 0
Fixed maturity securities, fair value	1,309	1,301
Other asset-backed
Schedule of Investments [Line Items]
Amortized cost	2,101	2,189
Gross unrealized gains	13	9
Gross unrealized losses	(28)	(57)
Allowance for credit losses	0	0
Fixed maturity securities, fair value	$ 2,086	$ 2,141