Investments (Summary of fixed maturity and equity securities) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fixed maturity securities available-for-sale:
Gross Unrealized Gains	$ 4,558	$ 5,795
Gross Unrealized Losses	112	77
Allowance for Credit Losses	18	40	$ 0
Estimated Fair Value	44,373	44,604
Total fixed maturity securities trading
Debt securities, amortized cost	39,952	38,953
Total fixed maturity securities	44,380	44,631
Corporate and other bonds
Fixed maturity securities available-for-sale:
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
Total fixed maturity securities trading
Total fixed maturity securities	24,852	25,234
States, municipalities and political subdivisions
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	10,358	9,729
Gross Unrealized Gains	1,599	1,863
Gross Unrealized Losses	14	0
Allowance for Credit Losses	0	0
Estimated Fair Value	11,943	11,592
Total fixed maturity securities trading
Total fixed maturity securities	11,943	11,592
Residential mortgage-backed
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	2,893	3,442
Gross Unrealized Gains	71	146
Gross Unrealized Losses	8	1
Allowance for Credit Losses	0	0
Estimated Fair Value	2,956	3,587
Commercial mortgage-backed
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	1,987	1,933
Gross Unrealized Gains	63	93
Gross Unrealized Losses	19	42
Allowance for Credit Losses	0	17
Estimated Fair Value	2,031	1,967
Other asset-backed
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	2,561	2,179
Gross Unrealized Gains	54	81
Gross Unrealized Losses	10	9
Allowance for Credit Losses	7	0
Estimated Fair Value	2,598	2,251
Asset-backed
Fixed maturity securities available-for-sale:
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
Total fixed maturity securities trading
Total fixed maturity securities	7,585	7,805
U.S. Treasury and obligations of government-sponsored enterprises
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	132	339
Gross Unrealized Gains	1	2
Gross Unrealized Losses	3	3
Allowance for Credit Losses	0	0
Estimated Fair Value	130	338
Foreign government
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	570	512
Gross Unrealized Gains	15	32
Gross Unrealized Losses	2	0
Allowance for Credit Losses	0	0
Estimated Fair Value	583	544
Fixed maturity securities
Fixed maturity securities available-for-sale:
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
Total fixed maturity securities trading
Total fixed maturity securities trading
Cost or amortized cost, trading securities	7	27
Estimated fair value, trading securities	$ 7	$ 27

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