Investments - Available-for-sale Securities in Gross Unrealized Loss Position (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Gross Unrealized Losses [Abstract]
Total, Estimated Fair Value	$ 28,266	$ 29,511
Total, Gross Unrealized Losses	3,418	4,056
Fixed maturity securities
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	15,037	25,234
Less than 12 Months, Gross Unrealized Losses	790	2,946
12 Months or Longer, Estimated Fair Value	13,229	4,277
12 Months or Longer, Gross Unrealized Losses	2,628	1,110
Total, Estimated Fair Value	28,266	29,511
Total, Gross Unrealized Losses	3,418	4,056
Corporate bonds and other
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	10,753	15,946
Less than 12 Months, Gross Unrealized Losses	545	1,585
12 Months or Longer, Estimated Fair Value	6,184	1,634
12 Months or Longer, Gross Unrealized Losses	1,130	424
Total, Estimated Fair Value	16,937	17,580
Total, Gross Unrealized Losses	1,675	2,009
States, municipalities and political subdivisions
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	1,708	4,079
Less than 12 Months, Gross Unrealized Losses	87	769
12 Months or Longer, Estimated Fair Value	2,347	456
12 Months or Longer, Gross Unrealized Losses	654	170
Total, Estimated Fair Value	4,055	4,535
Total, Gross Unrealized Losses	741	939
Residential mortgage-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	741	1,406
Less than 12 Months, Gross Unrealized Losses	28	144
12 Months or Longer, Estimated Fair Value	1,784	1,143
12 Months or Longer, Gross Unrealized Losses	385	303
Total, Estimated Fair Value	2,525	2,549
Total, Gross Unrealized Losses	413	447
Commercial mortgage-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	474	1,167
Less than 12 Months, Gross Unrealized Losses	36	159
12 Months or Longer, Estimated Fair Value	1,072	408
12 Months or Longer, Gross Unrealized Losses	206	96
Total, Estimated Fair Value	1,546	1,575
Total, Gross Unrealized Losses	242	255
Other asset-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	1,073	2,087
Less than 12 Months, Gross Unrealized Losses	86	262
12 Months or Longer, Estimated Fair Value	1,474	542
12 Months or Longer, Gross Unrealized Losses	220	99
Total, Estimated Fair Value	2,547	2,629
Total, Gross Unrealized Losses	306	361
Total asset-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	2,288	4,660
Less than 12 Months, Gross Unrealized Losses	150	565
12 Months or Longer, Estimated Fair Value	4,330	2,093
12 Months or Longer, Gross Unrealized Losses	811	498
Total, Estimated Fair Value	6,618	6,753
Total, Gross Unrealized Losses	961	1,063
U.S. Treasury and obligations of government-sponsored enterprises
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	57	76
Less than 12 Months, Gross Unrealized Losses	1	1
12 Months or Longer, Estimated Fair Value	41	16
12 Months or Longer, Gross Unrealized Losses	1	1
Total, Estimated Fair Value	98	92
Total, Gross Unrealized Losses	2	2
Foreign government
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	231	473
Less than 12 Months, Gross Unrealized Losses	7	26
12 Months or Longer, Estimated Fair Value	327	78
12 Months or Longer, Gross Unrealized Losses	32	17
Total, Estimated Fair Value	558	551
Total, Gross Unrealized Losses	$ 39	$ 43