Fair Value (Assets and liabilities measured at fair value on a recurring basis) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Fixed maturity securities:
Fixed maturity securities	$ 41,945	$ 44,380
Equity securities:
Equity securities	981	1,035
Short term and other	1,173	1,872
Total assets	44,099	47,287
Other liabilities	(16)	12
Total liabilities	(16)	12
Corporate and other bonds
Fixed maturity securities:
Fixed maturity securities	23,475	24,852
States, municipalities and political subdivisions
Fixed maturity securities:
Fixed maturity securities	11,059	11,943
Asset-backed
Fixed maturity securities:
Fixed maturity securities	7,411	7,585
Common Stock
Equity securities:
Equity securities	220	233
Non-redeemable preferred stock
Equity securities:
Equity securities	761	802
Level 1
Fixed maturity securities:
Fixed maturity securities	129	140
Equity securities:
Equity securities	254	285
Short term and other	1,146	1,798
Total assets	1,529	2,223
Other liabilities	0	0
Total liabilities	0	0
Level 1 | Corporate and other bonds
Fixed maturity securities:
Fixed maturity securities	129	140
Level 1 | States, municipalities and political subdivisions
Fixed maturity securities:
Fixed maturity securities	0	0
Level 1 | Asset-backed
Fixed maturity securities:
Fixed maturity securities	0	0
Level 1 | Common Stock
Equity securities:
Equity securities	191	220
Level 1 | Non-redeemable preferred stock
Equity securities:
Equity securities	63	65
Level 2
Fixed maturity securities:
Fixed maturity securities	40,246	42,691
Equity securities:
Equity securities	683	721
Short term and other	27	74
Total assets	40,956	43,486
Other liabilities	(16)	12
Total liabilities	(16)	12
Level 2 | Corporate and other bonds
Fixed maturity securities:
Fixed maturity securities	22,431	23,775
Level 2 | States, municipalities and political subdivisions
Fixed maturity securities:
Fixed maturity securities	11,008	11,887
Level 2 | Asset-backed
Fixed maturity securities:
Fixed maturity securities	6,807	7,029
Level 2 | Common Stock
Equity securities:
Equity securities	0	0
Level 2 | Non-redeemable preferred stock
Equity securities:
Equity securities	683	721
Level 3
Fixed maturity securities:
Fixed maturity securities	1,570	1,549
Equity securities:
Equity securities	44	29
Short term and other	0	0
Total assets	1,614	1,578
Other liabilities	0	0
Total liabilities	0	0
Level 3 | Corporate and other bonds
Fixed maturity securities:
Fixed maturity securities	915	937
Level 3 | States, municipalities and political subdivisions
Fixed maturity securities:
Fixed maturity securities	51	56
Level 3 | Asset-backed
Fixed maturity securities:
Fixed maturity securities	604	556
Level 3 | Common Stock
Equity securities:
Equity securities	29	13
Level 3 | Non-redeemable preferred stock
Equity securities:
Equity securities	$ 15	$ 16