Consolidated Statement of Earnings - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Property and casualty insurance net earned premiums	$ 5,185	$ 4,865	$ 4,579
Life, accident and health net earned premiums	22	24	22
Net investment income	2,303	2,094	1,831
Realized gains (losses) on:
Securities	287	(266)	5
Income (loss) of managed investment entities:
Investment income	269	255	210
Gain (loss) on change in fair value of assets/liabilities	(30)	(21)	12
Other income	201	199	206
Total revenues	8,237	7,150	6,865
Costs and Expenses:
Property and casualty insurance: Losses and loss adjustment expenses	3,271	3,003	2,955
Property and casualty insurance: Commissions and other underwriting expenses	1,725	1,583	1,407
Annuity benefits	1,151	998	892
Life, accident and health benefits	36	40	26
Annuity and supplemental insurance acquisition expenses	253	261	173
Interest charges on borrowed money	68	62	85
Expenses of managed investment entities	220	211	181
Other expenses	405	353	422
Total costs and expenses	7,129	6,511	6,141
Earnings before income taxes	1,108	639	724
Provision for income taxes	239	122	247
Net earnings, including noncontrolling interests	869	517	477
Less: Net earnings (losses) attributable to noncontrolling interests	(28)	(13)	2
Net Earnings Attributable to Shareholders	$ 897	$ 530	$ 475
Earnings Attributable to Shareholders per Common Share:
Basic (USD per share)	$ 9.98	$ 5.95	$ 5.40
Diluted (USD per share)	$ 9.85	$ 5.85	$ 5.28
Average number of Common Shares:
Basic (shares)	89.9	89.0	87.8
Diluted (shares)	91.0	90.6	89.8
Supplemental disclosure of Realized gains (losses) on securities:
Realized gains (losses) before impairments	$ 306	$ (247)	$ 78
Losses on securities with impairment	(19)	(19)	(74)
Non-credit portion recognized in other comprehensive income (loss)	0	0	1
Impairment charges recognized in earnings	(19)	(19)	(73)
Total realized gains (losses) on securities	$ 287	$ (266)	$ 5