Investments, Amortized Cost and Fair Values of Fixed Maturity Securities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	$ 39,952	$ 38,963
Gross Unrealized Gains	4,558	5,800
Gross Unrealized Losses	112	77
Allowance for Credit Losses	18	40	$ 0
Estimated Fair Value	44,380	44,646
Corporate bonds and other
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	21,444	20,792
Gross Unrealized Gains	2,755	3,578
Gross Unrealized Losses	56	22
Allowance for Credit Losses	11	23	0
Estimated Fair Value	24,132	24,325
States, municipalities and political subdivisions
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	10,358	9,729
Gross Unrealized Gains	1,599	1,863
Gross Unrealized Losses	14
Allowance for Credit Losses
Estimated Fair Value	11,943	11,592
Asset-backed
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	7,441	7,554
Gross Unrealized Gains	188	320
Gross Unrealized Losses	37	52
Allowance for Credit Losses	7	17	$ 0
Estimated Fair Value	7,585	7,805
Other asset-backed
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	2,561	2,179
Gross Unrealized Gains	54	81
Gross Unrealized Losses	10	9
Allowance for Credit Losses	7
Estimated Fair Value	2,598	2,251
Commercial mortgage-backed
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	1,987	1,933
Gross Unrealized Gains	63	93
Gross Unrealized Losses	19	42
Allowance for Credit Losses		17
Estimated Fair Value	2,031	1,967
Residential mortgage-backed
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	2,893	3,442
Gross Unrealized Gains	71	146
Gross Unrealized Losses	8	1
Allowance for Credit Losses
Estimated Fair Value	2,956	3,587
U.S. Treasury and obligations of government-sponsored enterprises
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	132	339
Gross Unrealized Gains	1	2
Gross Unrealized Losses	3	3
Allowance for Credit Losses
Estimated Fair Value	130	338
Foreign government
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	570	512
Gross Unrealized Gains	15	32
Gross Unrealized Losses	2
Allowance for Credit Losses
Estimated Fair Value	583	544
Fixed maturities available-for-sale
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	39,945	38,926
Gross Unrealized Gains	4,558	5,795
Gross Unrealized Losses	112	77
Allowance for Credit Losses	18	40
Estimated Fair Value	44,373	44,604
Fixed maturities trading
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	7	37
Gross Unrealized Gains		5
Gross Unrealized Losses
Allowance for Credit Losses
Estimated Fair Value	$ 7	$ 42

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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