Reinsurance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
SEC Schedule, 12-17, Insurance Companies, Reinsurance
Gross amounts, life insurance in force	$ 120,147	$ 116,697	$ 111,756
Gross amounts	7,050	6,370	5,985
Ceded amounts to other companies, life insurance in force	39,665	39,204	38,281
Ceded premiums earned	392	331	290
Assumed amounts from other companies, life insurance in force	0	0	0
Assumed amounts from other companies	561	443	285
Net amounts, life insurance in force	80,482	77,493	73,475
Premiums Earned, Net	$ 7,219	$ 6,482	$ 5,980
Percentage of amounts assumed to net, life insurance in force	0.00%	0.00%	0.00%
Percentage of amounts assumed to net	7.80%	6.80%	4.80%
Commercial Insurance
SEC Schedule, 12-17, Insurance Companies, Reinsurance
Gross amounts	$ 4,150	$ 3,777	$ 3,578
Ceded premiums earned	137	115	109
Assumed amounts from other companies	11	12	7
Premiums Earned, Net	$ 4,024	$ 3,674	$ 3,476
Percentage of amounts assumed to net	0.30%	0.30%	0.20%
Personal Insurance
SEC Schedule, 12-17, Insurance Companies, Reinsurance
Gross amounts	$ 1,755	$ 1,586	$ 1,503
Ceded premiums earned	67	45	41
Assumed amounts from other companies	1	1	1
Premiums Earned, Net	$ 1,689	$ 1,542	$ 1,463
Percentage of amounts assumed to net	0.10%	0.10%	0.10%
Excess and Surplus Lines Insurance
SEC Schedule, 12-17, Insurance Companies, Reinsurance
Gross amounts	$ 510	$ 417	$ 341
Ceded premiums earned	25	19	16
Assumed amounts from other companies	0	0	0
Premiums Earned, Net	$ 485	$ 398	$ 325
Percentage of amounts assumed to net	0.00%	0.00%	0.00%
Reinsurance assumed and other non segment
SEC Schedule, 12-17, Insurance Companies, Reinsurance
Gross amounts	$ 262	$ 216	$ 201
Ceded premiums earned	85	76	51
Assumed amounts from other companies	549	430	277
Premiums Earned, Net	$ 726	$ 570	$ 427
Percentage of amounts assumed to net	75.60%	75.40%	64.90%
Property, Liability and Casualty Insurance
SEC Schedule, 12-17, Insurance Companies, Reinsurance
Gross amounts	$ 6,677	$ 5,996	$ 5,623
Ceded premiums earned	314	255	217
Assumed amounts from other companies	561	443	285
Premiums Earned, Net	$ 6,924	$ 6,184	$ 5,691
Percentage of amounts assumed to net	8.10%	7.20%	5.00%
Life Insurance Segment
SEC Schedule, 12-17, Insurance Companies, Reinsurance
Gross amounts	$ 373	$ 374	$ 362
Ceded premiums earned	78	76	73
Assumed amounts from other companies	0	0	0
Premiums Earned, Net	$ 295	$ 298	$ 289
Percentage of amounts assumed to net	0.00%	0.00%	0.00%