Investments, Available-for-sale Securities in Gross Unrealized Loss Position (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Gross Unrealized Losses [Abstract]
Additional impairment losses	$ 0
Total fixed maturities
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	5,695	$ 1,666
Less than 12 Months, Gross Unrealized Losses	92	74
12 Months or Longer, Estimated Fair Value	370	64
12 Months or Longer, Gross Unrealized Losses	20	3
Total, Estimated Fair Value	6,065	1,730
Total, Gross Unrealized Losses	112	77
Corporate bonds and other
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	2,389	609
Less than 12 Months, Gross Unrealized Losses	48	21
12 Months or Longer, Estimated Fair Value	136	12
12 Months or Longer, Gross Unrealized Losses	8	1
Total, Estimated Fair Value	2,525	621
Total, Gross Unrealized Losses	56	22
States, municipalities and political subdivisions
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	730	33
Less than 12 Months, Gross Unrealized Losses	14
12 Months or Longer, Estimated Fair Value
12 Months or Longer, Gross Unrealized Losses
Total, Estimated Fair Value	730	33
Total, Gross Unrealized Losses	14
Residential mortgage-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	1,043	71
Less than 12 Months, Gross Unrealized Losses	8	1
12 Months or Longer, Estimated Fair Value		11
12 Months or Longer, Gross Unrealized Losses
Total, Estimated Fair Value	1,043	82
Total, Gross Unrealized Losses	8	1
Commercial mortgage-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	527	533
Less than 12 Months, Gross Unrealized Losses	7	40
12 Months or Longer, Estimated Fair Value	167	28
12 Months or Longer, Gross Unrealized Losses	12	2
Total, Estimated Fair Value	694	561
Total, Gross Unrealized Losses	19	42
Other asset-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	840	344
Less than 12 Months, Gross Unrealized Losses	10	9
12 Months or Longer, Estimated Fair Value	62	13
12 Months or Longer, Gross Unrealized Losses
Total, Estimated Fair Value	902	357
Total, Gross Unrealized Losses	10	9
Total asset-backed
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	2,410	948
Less than 12 Months, Gross Unrealized Losses	25	50
12 Months or Longer, Estimated Fair Value	229	52
12 Months or Longer, Gross Unrealized Losses	12	2
Total, Estimated Fair Value	2,639	1,000
Total, Gross Unrealized Losses	37	52
U.S. Treasury and obligations of government-sponsored enterprises
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	69	63
Less than 12 Months, Gross Unrealized Losses	3	3
12 Months or Longer, Estimated Fair Value	5
12 Months or Longer, Gross Unrealized Losses
Total, Estimated Fair Value	74	63
Total, Gross Unrealized Losses	3	3
Foreign government
Gross Unrealized Losses [Abstract]
Less than 12 Months, Estimated Fair Value	97	13
Less than 12 Months, Gross Unrealized Losses	2
12 Months or Longer, Estimated Fair Value
12 Months or Longer, Gross Unrealized Losses
Total, Estimated Fair Value	97	13
Total, Gross Unrealized Losses	$ 2