Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues
Property and casualty insurance premiums (net of reinsurance ceded of $971, $987 and $1,006)	$ 32,300	$ 31,307	$ 30,309
Life premiums and contract charges (net of reinsurance ceded of $303, $309 and $332)	2,378	2,275	2,158
Net investment income	3,401	3,042	3,156
Realized capital gains and losses:
Total other-than-temporary impairment (“OTTI”) losses	(146)	(313)	(452)
OTTI losses reclassified to other comprehensive income	(4)	10	36
Net OTTI losses recognized in earnings	(150)	(303)	(416)
Sales and other realized capital gains and losses	595	213	446
Total realized capital gains and losses	445	(90)	30
Total revenues	38,524	36,534	35,653
Costs and expenses
Property and casualty insurance claims and claims expense (net of reinsurance ceded of $1,807, $1,116 and $602)	21,929	22,221	21,034
Life contract benefits (net of reinsurance ceded of $179, $208 and $219)	1,923	1,857	1,803
Interest credited to contractholder funds (net of reinsurance ceded of $25, $26 and $25)	690	726	761
Amortization of deferred policy acquisition costs	4,784	4,550	4,364
Operating costs and expenses	4,658	4,106	4,081
Restructuring and related charges	109	30	39
Goodwill impairment	125	0	0
Interest expense	335	295	292
Total costs and expenses	34,553	33,785	32,374
Gain on disposition of operations	20	5	3
Income from operations before income tax expense	3,991	2,754	3,282
Income tax expense	802	877	1,111
Net income	3,189	1,877	2,171
Preferred stock dividends	116	116	116
Net income applicable to common shareholders	$ 3,073	$ 1,761	$ 2,055
Earnings per common share:
Net income applicable to common shareholders earnings per common share - Basic (in dollars per share)	$ 8.49	$ 4.72	$ 5.12
Weighted average common shares - Basic (in shares)	362.0	372.8	401.1
Net income applicable to common shareholders earnings per common share - Diluted (in dollars per share)	$ 8.36	$ 4.67	$ 5.05
Weighted average common shares - Diluted (in shares)	367.8	377.3	406.8
Cash dividends declared per common share (in dollars per share)	$ 1.48	$ 1.32	$ 1.20