Investments - Available-for-sale Securities in Gross Unrealized Loss Position (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Gross Unrealized Losses [Abstract]
Total, Estimated Fair Value	$ 29,612	$ 29,511
Total, Gross Unrealized Losses	3,786	4,056
Fixed maturity securities
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	11,350	25,234
Less than 12 Months, Gross Unrealized Losses	506	2,946
12 Months or Longer, Estimated Fair Value	18,262	4,277
12 Months or Longer, Gross Unrealized Losses	3,280	1,110
Total, Estimated Fair Value	29,612	29,511
Total, Gross Unrealized Losses	3,786	4,056
Corporate bonds and other
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	7,681	15,946
Less than 12 Months, Gross Unrealized Losses	350	1,585
12 Months or Longer, Estimated Fair Value	10,087	1,634
12 Months or Longer, Gross Unrealized Losses	1,559	424
Total, Estimated Fair Value	17,768	17,580
Total, Gross Unrealized Losses	1,909	2,009
States, municipalities and political subdivisions
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	1,486	4,079
Less than 12 Months, Gross Unrealized Losses	64	769
12 Months or Longer, Estimated Fair Value	2,783	456
12 Months or Longer, Gross Unrealized Losses	729	170
Total, Estimated Fair Value	4,269	4,535
Total, Gross Unrealized Losses	793	939
Residential mortgage-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	822	1,406
Less than 12 Months, Gross Unrealized Losses	35	144
12 Months or Longer, Estimated Fair Value	1,810	1,143
12 Months or Longer, Gross Unrealized Losses	409	303
Total, Estimated Fair Value	2,632	2,549
Total, Gross Unrealized Losses	444	447
Commercial mortgage-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	325	1,167
Less than 12 Months, Gross Unrealized Losses	15	159
12 Months or Longer, Estimated Fair Value	1,171	408
12 Months or Longer, Gross Unrealized Losses	242	96
Total, Estimated Fair Value	1,496	1,575
Total, Gross Unrealized Losses	257	255
Other asset-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	739	2,087
Less than 12 Months, Gross Unrealized Losses	32	262
12 Months or Longer, Estimated Fair Value	1,982	542
12 Months or Longer, Gross Unrealized Losses	298	99
Total, Estimated Fair Value	2,721	2,629
Total, Gross Unrealized Losses	330	361
Total asset-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	1,886	4,660
Less than 12 Months, Gross Unrealized Losses	82	565
12 Months or Longer, Estimated Fair Value	4,963	2,093
12 Months or Longer, Gross Unrealized Losses	949	498
Total, Estimated Fair Value	6,849	6,753
Total, Gross Unrealized Losses	1,031	1,063
U.S. Treasury and obligations of government-sponsored enterprises
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	84	76
Less than 12 Months, Gross Unrealized Losses	2	1
12 Months or Longer, Estimated Fair Value	34	16
12 Months or Longer, Gross Unrealized Losses	1	1
Total, Estimated Fair Value	118	92
Total, Gross Unrealized Losses	3	2
Foreign government
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	213	473
Less than 12 Months, Gross Unrealized Losses	8	26
12 Months or Longer, Estimated Fair Value	395	78
12 Months or Longer, Gross Unrealized Losses	42	17
Total, Estimated Fair Value	608	551
Total, Gross Unrealized Losses	$ 50	$ 43