Investments - Schedule of Gross Unrealized Losses and Fair Value of Corporate Securities Based on Industries (Details) $ in Millions	Dec. 31, 2025 USD ($) security	Dec. 31, 2024 USD ($) security
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 2,786	$ 8,576
Less than 12 months, Gross unrealized losses	$ (82)	$ (289)
Less than 12 months, number of securities in a continuous loss position | security	610	1,523
12 months or more, Fair value	$ 23,303	$ 24,438
12 months or more, Gross unrealized losses	$ (3,145)	$ (3,964)
12 months or more, Number of securities in a continuous loss position | security	3,069	3,460
Fair value	$ 26,089	$ 33,014
Gross unrealized losses	$ (3,227)	$ (4,253)
Number of securities | security	3,679	4,983
U.S. corporate
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 1,664	$ 5,001
Less than 12 months, Gross unrealized losses	$ (57)	$ (173)
Less than 12 months, number of securities in a continuous loss position | security	399	894
12 months or more, Fair value	$ 14,057	$ 14,626
12 months or more, Gross unrealized losses	$ (1,811)	$ (2,302)
12 months or more, Number of securities in a continuous loss position | security	1,814	1,997
Fair value	$ 15,721	$ 19,627
Gross unrealized losses	$ (1,868)	$ (2,475)
Number of securities | security	2,213	2,891
U.S. corporate | Utilities
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 319	$ 1,005
Less than 12 months, Gross unrealized losses	$ (8)	$ (26)
Less than 12 months, number of securities in a continuous loss position | security	66	151
12 months or more, Fair value	$ 2,109	$ 1,968
12 months or more, Gross unrealized losses	$ (367)	$ (424)
12 months or more, Number of securities in a continuous loss position | security	320	303
Fair value	$ 2,428	$ 2,973
Gross unrealized losses	$ (375)	$ (450)
Number of securities | security	386	454
U.S. corporate | Energy
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 147	$ 491
Less than 12 months, Gross unrealized losses	$ (5)	$ (25)
Less than 12 months, number of securities in a continuous loss position | security	30	107
12 months or more, Fair value	$ 1,009	$ 1,051
12 months or more, Gross unrealized losses	$ (118)	$ (145)
12 months or more, Number of securities in a continuous loss position | security	134	137
Fair value	$ 1,156	$ 1,542
Gross unrealized losses	$ (123)	$ (170)
Number of securities | security	164	244
U.S. corporate | Finance and insurance
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 329	$ 917
Less than 12 months, Gross unrealized losses	$ (5)	$ (26)
Less than 12 months, number of securities in a continuous loss position | security	95	172
12 months or more, Fair value	$ 4,198	$ 4,472
12 months or more, Gross unrealized losses	$ (482)	$ (643)
12 months or more, Number of securities in a continuous loss position | security	514	584
Fair value	$ 4,527	$ 5,389
Gross unrealized losses	$ (487)	$ (669)
Number of securities | security	609	756
U.S. corporate | Consumer—non-cyclical
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 239	$ 917
Less than 12 months, Gross unrealized losses	$ (3)	$ (34)
Less than 12 months, number of securities in a continuous loss position | security	60	160
12 months or more, Fair value	$ 2,368	$ 2,267
12 months or more, Gross unrealized losses	$ (276)	$ (358)
12 months or more, Number of securities in a continuous loss position | security	261	289
Fair value	$ 2,607	$ 3,184
Gross unrealized losses	$ (279)	$ (392)
Number of securities | security	321	449
U.S. corporate | Technology and communications
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 259	$ 454
Less than 12 months, Gross unrealized losses	$ (16)	$ (16)
Less than 12 months, number of securities in a continuous loss position | security	63	86
12 months or more, Fair value	$ 1,573	$ 1,772
12 months or more, Gross unrealized losses	$ (240)	$ (295)
12 months or more, Number of securities in a continuous loss position | security	195	235
Fair value	$ 1,832	$ 2,226
Gross unrealized losses	$ (256)	$ (311)
Number of securities | security	258	321
U.S. corporate | Industrial
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 56	$ 220
Less than 12 months, Gross unrealized losses	$ (1)	$ (8)
Less than 12 months, number of securities in a continuous loss position | security	18	34
12 months or more, Fair value	$ 575	$ 565
12 months or more, Gross unrealized losses	$ (82)	$ (97)
12 months or more, Number of securities in a continuous loss position | security	81	90
Fair value	$ 631	$ 785
Gross unrealized losses	$ (83)	$ (105)
Number of securities | security	99	124
U.S. corporate | Capital goods
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 146	$ 464
Less than 12 months, Gross unrealized losses	$ (3)	$ (21)
Less than 12 months, number of securities in a continuous loss position | security	37	81
12 months or more, Fair value	$ 983	$ 1,009
12 months or more, Gross unrealized losses	$ (102)	$ (133)
12 months or more, Number of securities in a continuous loss position | security	128	144
Fair value	$ 1,129	$ 1,473
Gross unrealized losses	$ (105)	$ (154)
Number of securities | security	165	225
U.S. corporate | Consumer—cyclical
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 0	$ 277
Less than 12 months, Gross unrealized losses	$ 0	$ (10)
Less than 12 months, number of securities in a continuous loss position | security	0	58
12 months or more, Fair value	$ 715	$ 883
12 months or more, Gross unrealized losses	$ (69)	$ (108)
12 months or more, Number of securities in a continuous loss position | security	103	126
Fair value	$ 715	$ 1,160
Gross unrealized losses	$ (69)	$ (118)
Number of securities | security	103	184
U.S. corporate | Transportation
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 130	$ 187
Less than 12 months, Gross unrealized losses	$ (10)	$ (6)
Less than 12 months, number of securities in a continuous loss position | security	24	37
12 months or more, Fair value	$ 449	$ 529
12 months or more, Gross unrealized losses	$ (67)	$ (85)
12 months or more, Number of securities in a continuous loss position | security	67	73
Fair value	$ 579	$ 716
Gross unrealized losses	$ (77)	$ (91)
Number of securities | security	91	110
U.S. corporate | Other
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 39	$ 69
Less than 12 months, Gross unrealized losses	$ (6)	$ (1)
Less than 12 months, number of securities in a continuous loss position | security	6	8
12 months or more, Fair value	$ 78	$ 110
12 months or more, Gross unrealized losses	$ (8)	$ (14)
12 months or more, Number of securities in a continuous loss position | security	11	16
Fair value	$ 117	$ 179
Gross unrealized losses	$ (14)	$ (15)
Number of securities | security	17	24
Non-U.S. corporate
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 244	$ 1,359
Less than 12 months, Gross unrealized losses	$ (11)	$ (34)
Less than 12 months, number of securities in a continuous loss position | security	57	238
12 months or more, Fair value	$ 3,495	$ 4,126
12 months or more, Gross unrealized losses	$ (366)	$ (538)
12 months or more, Number of securities in a continuous loss position | security	438	553
Fair value	$ 3,739	$ 5,485
Gross unrealized losses	$ (377)	$ (572)
Number of securities | security	495	791
Non-U.S. corporate | Utilities
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 0	$ 152
Less than 12 months, Gross unrealized losses	$ 0	$ (3)
Less than 12 months, number of securities in a continuous loss position | security	0	23
12 months or more, Fair value	$ 386	$ 455
12 months or more, Gross unrealized losses	$ (36)	$ (51)
12 months or more, Number of securities in a continuous loss position | security	43	51
Fair value	$ 386	$ 607
Gross unrealized losses	$ (36)	$ (54)
Number of securities | security	43	74
Non-U.S. corporate | Energy
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 78	$ 223
Less than 12 months, Gross unrealized losses	$ (6)	$ (7)
Less than 12 months, number of securities in a continuous loss position | security	16	33
12 months or more, Fair value	$ 358	$ 435
12 months or more, Gross unrealized losses	$ (30)	$ (49)
12 months or more, Number of securities in a continuous loss position | security	49	48
Fair value	$ 436	$ 658
Gross unrealized losses	$ (36)	$ (56)
Number of securities | security	65	81
Non-U.S. corporate | Finance and insurance
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 85	$ 270
Less than 12 months, Gross unrealized losses	$ (1)	$ (4)
Less than 12 months, number of securities in a continuous loss position | security	14	58
12 months or more, Fair value	$ 800	$ 1,116
12 months or more, Gross unrealized losses	$ (74)	$ (119)
12 months or more, Number of securities in a continuous loss position | security	109	157
Fair value	$ 885	$ 1,386
Gross unrealized losses	$ (75)	$ (123)
Number of securities | security	123	215
Non-U.S. corporate | Consumer—non-cyclical
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 0	$ 110
Less than 12 months, Gross unrealized losses	$ 0	$ (7)
Less than 12 months, number of securities in a continuous loss position | security	0	24
12 months or more, Fair value	$ 390	$ 365
12 months or more, Gross unrealized losses	$ (64)	$ (72)
12 months or more, Number of securities in a continuous loss position | security	43	48
Fair value	$ 390	$ 475
Gross unrealized losses	$ (64)	$ (79)
Number of securities | security	43	72
Non-U.S. corporate | Technology and communications
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 29	$ 114
Less than 12 months, Gross unrealized losses	$ (2)	$ (4)
Less than 12 months, number of securities in a continuous loss position | security	13	18
12 months or more, Fair value	$ 435	$ 489
12 months or more, Gross unrealized losses	$ (61)	$ (76)
12 months or more, Number of securities in a continuous loss position | security	48	65
Fair value	$ 464	$ 603
Gross unrealized losses	$ (63)	$ (80)
Number of securities | security	61	83
Non-U.S. corporate | Industrial
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 18	$ 152
Less than 12 months, Gross unrealized losses	$ (1)	$ (2)
Less than 12 months, number of securities in a continuous loss position | security	10	33
12 months or more, Fair value	$ 259	$ 340
12 months or more, Gross unrealized losses	$ (26)	$ (44)
12 months or more, Number of securities in a continuous loss position | security	35	51
Fair value	$ 277	$ 492
Gross unrealized losses	$ (27)	$ (46)
Number of securities | security	45	84
Non-U.S. corporate | Capital goods
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 0	$ 118
Less than 12 months, Gross unrealized losses	$ 0	$ (3)
Less than 12 months, number of securities in a continuous loss position | security	0	18
12 months or more, Fair value	$ 332	$ 313
12 months or more, Gross unrealized losses	$ (29)	$ (43)
12 months or more, Number of securities in a continuous loss position | security	42	43
Fair value	$ 332	$ 431
Gross unrealized losses	$ (29)	$ (46)
Number of securities | security	42	61
Non-U.S. corporate | Consumer—cyclical
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 0	$ 52
Less than 12 months, Gross unrealized losses	$ 0	$ (1)
Less than 12 months, number of securities in a continuous loss position | security	0	8
12 months or more, Fair value	$ 130	$ 117
12 months or more, Gross unrealized losses	$ (8)	$ (15)
12 months or more, Number of securities in a continuous loss position | security	15	20
Fair value	$ 130	$ 169
Gross unrealized losses	$ (8)	$ (16)
Number of securities | security	15	28
Non-U.S. corporate | Transportation
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 34	$ 34
Less than 12 months, Gross unrealized losses	$ (1)	$ (1)
Less than 12 months, number of securities in a continuous loss position | security	4	4
12 months or more, Fair value	$ 229	$ 247
12 months or more, Gross unrealized losses	$ (20)	$ (28)
12 months or more, Number of securities in a continuous loss position | security	29	34
Fair value	$ 263	$ 281
Gross unrealized losses	$ (21)	$ (29)
Number of securities | security	33	38
Non-U.S. corporate | Other
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 0	$ 134
Less than 12 months, Gross unrealized losses	$ 0	$ (2)
Less than 12 months, number of securities in a continuous loss position | security	0	19
12 months or more, Fair value	$ 176	$ 249
12 months or more, Gross unrealized losses	$ (18)	$ (41)
12 months or more, Number of securities in a continuous loss position | security	25	36
Fair value	$ 176	$ 383
Gross unrealized losses	$ (18)	$ (43)
Number of securities | security	25	55
Corporate Debt Securities
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months, Fair value	$ 1,908	$ 6,360
Less than 12 months, Gross unrealized losses	$ (68)	$ (207)
Less than 12 months, number of securities in a continuous loss position | security	456	1,132
12 months or more, Fair value	$ 17,552	$ 18,752
12 months or more, Gross unrealized losses	$ (2,177)	$ (2,840)
12 months or more, Number of securities in a continuous loss position | security	2,252	2,550
Fair value	$ 19,460	$ 25,112
Gross unrealized losses	$ (2,245)	$ (3,047)
Number of securities | security	2,708	3,682