Investments - Available-for-sale Securities in Gross Unrealized Loss Position (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Gross Unrealized Losses [Abstract]
Total, Estimated Fair Value	$ 27,288	$ 25,731
Total, Gross Unrealized Losses	3,039	2,995
Total fixed maturities
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	8,969	3,483
Less than 12 Months, Gross Unrealized Losses	266	74
12 Months or Longer, Estimated Fair Value	18,319	22,248
12 Months or Longer, Gross Unrealized Losses	2,773	2,921
Total, Estimated Fair Value	27,288	25,731
Total, Gross Unrealized Losses	3,039	2,995
Corporate bonds and other
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	5,846	1,943
Less than 12 Months, Gross Unrealized Losses	165	37
12 Months or Longer, Estimated Fair Value	10,388	13,406
12 Months or Longer, Gross Unrealized Losses	1,140	1,308
Total, Estimated Fair Value	16,234	15,349
Total, Gross Unrealized Losses	1,305	1,345
States, municipalities and political subdivisions
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	1,247	598
Less than 12 Months, Gross Unrealized Losses	52	18
12 Months or Longer, Estimated Fair Value	2,967	3,104
12 Months or Longer, Gross Unrealized Losses	783	685
Total, Estimated Fair Value	4,214	3,702
Total, Gross Unrealized Losses	835	703
Residential mortgage-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	849	233
Less than 12 Months, Gross Unrealized Losses	22	4
12 Months or Longer, Estimated Fair Value	2,010	2,212
12 Months or Longer, Gross Unrealized Losses	466	421
Total, Estimated Fair Value	2,859	2,445
Total, Gross Unrealized Losses	488	425
Commercial mortgage-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	180	200
Less than 12 Months, Gross Unrealized Losses	2	5
12 Months or Longer, Estimated Fair Value	988	1,184
12 Months or Longer, Gross Unrealized Losses	139	225
Total, Estimated Fair Value	1,168	1,384
Total, Gross Unrealized Losses	141	230
Other asset-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	680	392
Less than 12 Months, Gross Unrealized Losses	21	8
12 Months or Longer, Estimated Fair Value	1,557	1,869
12 Months or Longer, Gross Unrealized Losses	218	248
Total, Estimated Fair Value	2,237	2,261
Total, Gross Unrealized Losses	239	256
Total asset-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	1,709	825
Less than 12 Months, Gross Unrealized Losses	45	17
12 Months or Longer, Estimated Fair Value	4,555	5,265
12 Months or Longer, Gross Unrealized Losses	823	894
Total, Estimated Fair Value	6,264	6,090
Total, Gross Unrealized Losses	868	911
U.S. Treasury and obligations of government-sponsored enterprises
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	49	65
Less than 12 Months, Gross Unrealized Losses	1	1
12 Months or Longer, Estimated Fair Value	41	23
12 Months or Longer, Gross Unrealized Losses		1
Total, Estimated Fair Value	90	88
Total, Gross Unrealized Losses	1	2
Foreign government
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	118	52
Less than 12 Months, Gross Unrealized Losses	3	1
12 Months or Longer, Estimated Fair Value	368	450
12 Months or Longer, Gross Unrealized Losses	27	33
Total, Estimated Fair Value	486	502
Total, Gross Unrealized Losses	$ 30	$ 34