Fair Value (Assets and liabilities measured at fair value on a recurring basis) (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Fixed maturity securities:
Fixed maturity securities	$ 38,728	$ 37,627	[1]
Equity securities:
Equity securities	683	674	[1]
Short term and other	1,753	1,679
Total assets	41,164	39,980
Other liabilities	1	1
Total liabilities	1	1
Corporate and other bonds
Fixed maturity securities:
Fixed maturity securities	23,394	22,117
States, municipalities and political subdivisions
Fixed maturity securities:
Fixed maturity securities	7,810	8,317
Asset-backed
Fixed maturity securities:
Fixed maturity securities	7,524	7,193
Common Stock
Equity securities:
Equity securities	205	185
Non-redeemable preferred stock
Equity securities:
Equity securities	478	489
Level 1
Fixed maturity securities:
Fixed maturity securities	137	120
Equity securities:
Equity securities	235	204
Short term and other	1,711	1,608
Total assets	2,083	1,932
Other liabilities	0	0
Total liabilities	0	0
Level 1 | Corporate and other bonds
Fixed maturity securities:
Fixed maturity securities	137	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	179	150
Level 1 | Non-redeemable preferred stock
Equity securities:
Equity securities	56	54
Level 2
Fixed maturity securities:
Fixed maturity securities	36,694	35,866
Equity securities:
Equity securities	422	435
Short term and other	42	71
Total assets	37,158	36,372
Other liabilities	1	1
Total liabilities	1	1
Level 2 | Corporate and other bonds
Fixed maturity securities:
Fixed maturity securities	22,286	21,187
Level 2 | States, municipalities and political subdivisions
Fixed maturity securities:
Fixed maturity securities	7,767	8,274
Level 2 | Asset-backed
Fixed maturity securities:
Fixed maturity securities	6,641	6,405
Level 2 | Common Stock
Equity securities:
Equity securities	0	0
Level 2 | Non-redeemable preferred stock
Equity securities:
Equity securities	422	435
Level 3
Fixed maturity securities:
Fixed maturity securities	1,897	1,641
Equity securities:
Equity securities	26	35
Short term and other	0	0
Total assets	1,923	1,676
Other liabilities	0	0
Total liabilities	0	0
Level 3 | Corporate and other bonds
Fixed maturity securities:
Fixed maturity securities	971	810
Level 3 | States, municipalities and political subdivisions
Fixed maturity securities:
Fixed maturity securities	43	43
Level 3 | Asset-backed
Fixed maturity securities:
Fixed maturity securities	883	788
Level 3 | Common Stock
Equity securities:
Equity securities	26	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.