Consolidated Statement of Earnings (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues:
Property and casualty insurance net earned premiums	$ 1,250	$ 1,184	$ 2,423	$ 2,393
Net investment income	164	88	352	192
Realized gains (losses) on securities	43	108	120	(220)
Realized gain on subsidiary	4	0	4	0
Income of managed investment entities:
Investment income	44	49	90	108
Gain (loss) on change in fair value of assets/liabilities	6	(3)	8	(16)
Other income	20	19	43	43
Total revenues	1,531	1,445	3,040	2,500
Costs and Expenses:
Losses and loss adjustment expenses	714	771	1,381	1,478
Commissions and other underwriting expenses	390	409	770	829
Interest charges on borrowed money	23	23	47	40
Expenses of managed investment entities	39	42	78	95
Other expenses	77	60	141	103
Total costs and expenses	1,243	1,305	2,417	2,545
Earnings (loss) from continuing operations before income taxes	288	140	623	(45)
Provision (credit) for income taxes	48	37	116	(4)
Net earnings (loss) from continuing operations, including noncontrolling interests	240	103	507	(41)
Net earnings (loss) from discontinued operations	762	64	914	(96)
Net earnings (loss), including noncontrolling interests	1,002	167	1,421	(137)
Less: Net earnings (loss) from continuing operations attributable to noncontrolling interests	0	(10)	0	(13)
Net Earnings (Loss) Attributable to Shareholders	$ 1,002	$ 177	$ 1,421	$ (124)
Earnings (Loss) Attributable to Shareholders per Basic Common Share from:
Basic (USD per share) from continuing operations	$ 2.83	$ 1.26	$ 5.94	$ (0.31)
Basic (USD per share) from discontinued operations	8.95	0.72	10.69	(1.07)
Basic (USD per share)	11.78	1.98	16.63	(1.38)
Earnings (Loss) Attributable to Shareholders per Diluted Common Share:
Diluted (USD per share) from continuing operations)	2.81	1.26	5.90	(0.31)
Diluted (USD per share) from discontinued operations	8.89	0.71	10.61	(1.07)
Diluted (USD per share)	$ 11.70	$ 1.97	$ 16.51	$ (1.38)
Average number of Common Shares:
Basic (shares)	85.0	89.7	85.5	90.0
Diluted (shares)	85.6	90.0	86.1	90.0