Investments (Summary of fixed maturity and equity securities) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022		Mar. 31, 2022	Dec. 31, 2021
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	$ 41,646	$ 41,032
Gross Unrealized Gains	867	652
Gross Unrealized Losses	3,418	4,056
Allowance for Credit Losses	2	1		$ 17	$ 18
Estimated Fair Value	39,093	37,627
Total fixed maturity securities trading
Debt securities, amortized cost	41,660	41,032
Total fixed maturity securities	39,107	37,627	[1]
Corporate and other bonds
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	24,140	23,137
Gross Unrealized Gains	437	301
Gross Unrealized Losses	1,675	2,009
Allowance for Credit Losses	1	0		12	11
Estimated Fair Value	22,901	21,429
Total fixed maturity securities trading
Total fixed maturity securities	23,651	22,117
States, municipalities and political subdivisions
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	8,332	8,918
Gross Unrealized Gains	410	338
Gross Unrealized Losses	741	939
Allowance for Credit Losses	0	0
Estimated Fair Value	8,001	8,317
Total fixed maturity securities trading
Total fixed maturity securities	8,001	8,317
Asset-backed
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	8,398	8,246
Gross Unrealized Gains	19	11
Gross Unrealized Losses	961	1,063
Allowance for Credit Losses	1	1		$ 5	$ 7
Estimated Fair Value	7,455	7,193
Total fixed maturity securities trading
Total fixed maturity securities	7,455	7,193
Residential mortgage-backed
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	3,066	3,073
Gross Unrealized Gains	6	5
Gross Unrealized Losses	413	447
Allowance for Credit Losses	0	0
Estimated Fair Value	2,659	2,631
Commercial mortgage-backed
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	1,868	1,886
Gross Unrealized Gains	5	4
Gross Unrealized Losses	242	255
Allowance for Credit Losses	0	0
Estimated Fair Value	1,631	1,635
Other asset-backed
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	3,464	3,287
Gross Unrealized Gains	8	2
Gross Unrealized Losses	306	361
Allowance for Credit Losses	1	1
Estimated Fair Value	3,165	2,927
U.S. Treasury and obligations of government-sponsored enterprises
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	126	111
Gross Unrealized Gains	0	1
Gross Unrealized Losses	2	2
Allowance for Credit Losses	0	0
Estimated Fair Value	124	110
Foreign government
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	647	617
Gross Unrealized Gains	1	1
Gross Unrealized Losses	39	43
Allowance for Credit Losses	0	0
Estimated Fair Value	609	575
Redeemable preferred stock
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	3	3
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Allowance for Credit Losses	0	0
Estimated Fair Value	3	3
Total fixed maturity securities trading
Total fixed maturity securities trading
Cost or Amortized Cost	14	0
Estimated Fair Value	$ 14	$ 0

[1] As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Condensed Consolidated Financial Statements for additional information.