Consolidated Statement of Earnings - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Property and casualty insurance net earned premiums	$ 4,328	$ 4,224	$ 3,878
Life, accident and health net earned premiums	24	104	108
Net investment income	1,696	1,633	1,501
Realized gains (losses) on:
Securities	19	(19)	52
Subsidiaries	2	(161)	0
Income (loss) of managed investment entities:
Investment income	190	155	116
Gain (loss) on change in fair value of assets/liabilities	15	(34)	(44)
Other income	224	243	122
Total revenues	6,498	6,145	5,733
Costs and Expenses:
Property and casualty insurance: Losses and loss adjustment expenses	2,762	2,695	2,494
Property and casualty insurance: Commissions and other underwriting expenses	1,349	1,320	1,172
Annuity benefits	800	732	648
Life, accident and health benefits	33	131	164
Annuity and supplemental insurance acquisition expenses	186	179	193
Interest charges on borrowed money	77	75	74
Expenses of managed investment entities	151	112	82
Other expenses	353	336	280
Total costs and expenses	5,711	5,580	5,107
Earnings before income taxes	787	565	626
Provision for income taxes	119	195	220
Net earnings, including noncontrolling interests	668	370	406
Less: Net earnings (loss) attributable to noncontrolling interests	19	18	(46)
Net Earnings Attributable to Shareholders	$ 649	$ 352	$ 452
Earnings Attributable to Shareholders per Common Share:
Basic (USD per share)	$ 7.47	$ 4.02	$ 5.07
Diluted (USD per share)	$ 7.33	$ 3.94	$ 4.97
Average number of Common Shares:
Basic (shares)	86.9	87.6	89.0
Diluted (shares)	88.5	89.4	91.0
Cash dividends per Common Share (USD per share)	$ 2.1525	$ 2.03	$ 1.91
Supplemental disclosure of Realized gains (losses) on securities:
Realized gains before impairments	$ 135	$ 106	$ 88
Losses on securities with impairment	(115)	(125)	(36)
Non-credit portion recognized in other comprehensive income (loss)	(1)	0	0
Impairment charges recognized in earnings	(116)	(125)	(36)
Total realized gains (losses) on securities	$ 19	$ (19)	$ 52