Fair Value (Assets and liabilities measured at fair value on a recurring basis) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Fixed maturity securities:
Fixed maturity securities	$ 39,107	$ 37,627	[1]
Equity securities:
Equity securities	682	674	[1]
Short term and other	1,002	1,679
Total assets	40,791	39,980
Other liabilities	1	1
Total liabilities	1	1
Corporate and other bonds
Fixed maturity securities:
Fixed maturity securities	23,651	22,117
States, municipalities and political subdivisions
Fixed maturity securities:
Fixed maturity securities	8,001	8,317
Asset-backed
Fixed maturity securities:
Fixed maturity securities	7,455	7,193
Common Stock
Equity securities:
Equity securities	206	185
Non-redeemable preferred stock
Equity securities:
Equity securities	476	489
Level 1
Fixed maturity securities:
Fixed maturity securities	135	120
Equity securities:
Equity securities	232	204
Short term and other	975	1,608
Total assets	1,342	1,932
Other liabilities	0	0
Total liabilities	0	0
Level 1 | Corporate and other bonds
Fixed maturity securities:
Fixed maturity securities	135	120
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	177	150
Level 1 | Non-redeemable preferred stock
Equity securities:
Equity securities	55	54
Level 2
Fixed maturity securities:
Fixed maturity securities	37,157	35,866
Equity securities:
Equity securities	421	435
Short term and other	27	71
Total assets	37,605	36,372
Other liabilities	1	1
Total liabilities	1	1
Level 2 | Corporate and other bonds
Fixed maturity securities:
Fixed maturity securities	22,604	21,187
Level 2 | States, municipalities and political subdivisions
Fixed maturity securities:
Fixed maturity securities	7,957	8,274
Level 2 | Asset-backed
Fixed maturity securities:
Fixed maturity securities	6,596	6,405
Level 2 | Common Stock
Equity securities:
Equity securities	0	0
Level 2 | Non-redeemable preferred stock
Equity securities:
Equity securities	421	435
Level 3
Fixed maturity securities:
Fixed maturity securities	1,815	1,641
Equity securities:
Equity securities	29	35
Short term and other	0	0
Total assets	1,844	1,676
Other liabilities	0	0
Total liabilities	0	0
Level 3 | Corporate and other bonds
Fixed maturity securities:
Fixed maturity securities	912	810
Level 3 | States, municipalities and political subdivisions
Fixed maturity securities:
Fixed maturity securities	44	43
Level 3 | Asset-backed
Fixed maturity securities:
Fixed maturity securities	859	788
Level 3 | Common Stock
Equity securities:
Equity securities	29	35
Level 3 | Non-redeemable preferred stock
Equity securities:
Equity securities	$ 0	$ 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.