Investments - Unrealized Capital Losses (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 33
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,982	$ 861
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	2,015	2,628
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value		15,388
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value	15,327	18,531
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	863
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	$ 14,464	3,143
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss		1,767
Minimum
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Fixed Maturities Average Duration	6 years 6 months
Maximum
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Fixed Maturities Average Duration	7 years
U.S. Treasuries
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	23	1
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	25	31
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value		223
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value	165	225
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	60
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	105	2
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss		30
State, municipalities and political subdivisions
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	70	7
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	70	92
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value		545
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value	544	560
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	16
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	528	15
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss		85
U.S. corporate public securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	13
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	746	419
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	759	1,032
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value		4,290
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value	4,448	5,288
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	215
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	4,233	998
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss		613
U.S. corporate private securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	251	64
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	256	328
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value		2,819
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value	2,781	3,150
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	128
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	2,653	331
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss		264
Foreign corporate public securities and foreign governments
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	215	116
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	216	317
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value		1,509
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value	1,455	1,807
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	70
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1,385	298
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss		201
Foreign corporate private securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	101	11
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	105	184
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value		2,203
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value	1,895	2,255
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	151
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1,744	52
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss		173
Residential mortgage-backed securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	122	75
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	124	153
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value		1,065
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value	877	1,393
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	74
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	803	328
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss		78
Commercial mortgage-backed securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	412	127
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	415	379
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value		1,792
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value	2,304	2,551
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	52
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	2,252	759
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss		252
Other asset-backed securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	40	41
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	43	109
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value		912
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value	841	1,272
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	97
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	744	360
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss		68
U.S. Government agencies and authorities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	3
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value		30
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value		$ 30
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	0
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss	3
US Government Corporations and Agencies Securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	2
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value	17
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	$ 17