Consolidated Statement of Earnings - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenues:
Property and casualty insurance net earned premiums	$ 6,085	$ 5,404	$ 5,099
Net investment income	717	730	461
Realized gains (losses) on:
Securities	(116)	110	(75)
Realized gains on subsidiaries	0	4	23
Income of managed investment entities:
Investment income	268	181	201
Gain (loss) on change in fair value of assets/liabilities	(31)	10	(20)
Other income	117	113	80
Total revenues	7,040	6,552	5,769
Costs and Expenses:
Losses and loss adjustment expenses	3,629	3,157	3,271
Commissions and other underwriting expenses	1,718	1,547	1,625
Interest charges on borrowed money	85	94	88
Expenses of managed investment entities	230	155	167
Other expenses	255	264	279
Total costs and expenses	5,917	5,217	5,430
Earnings from continuing operations before income taxes	1,123	1,335	339
Provision for income taxes	225	254	25
Net earnings from continuing operations, including noncontrolling interests	898	1,081	314
Net earnings from discontinued operations	0	914	407
Net earnings, including noncontrolling interests	898	1,995	721
Less: Net earnings (loss) from continuing operations attributable to noncontrolling interests	0	0	(11)
Net Earnings Attributable to Shareholders	$ 898	$ 1,995	$ 732
Earnings Attributable to Shareholders per Basic Common Share from:
Basic (USD per share) from continuing operations	$ 10.55	$ 12.70	$ 3.66
Basic (USD per share) from discontinued operations	0	10.74	4.59
Basic (USD per share)	10.55	23.44	8.25
Earnings Attributable to Shareholders per Diluted Common Share:
Diluted (USD per share) from continuing operations	10.53	12.62	3.63
Diluted (USD per share) from discontinued operations	0	10.68	4.57
Diluted (USD per share)	$ 10.53	$ 23.30	$ 8.20
Average number of Common Shares:
Basic (shares)	85.1	85.1	88.7
Diluted (shares)	85.3	85.6	89.2