Condensed Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Investments
Fixed maturities, at fair value (amortized cost: 2013—$8,428; 2012—$8,222)	$ 8,992	$ 9,093
Equity securities, at fair value (cost: 2013—$2,452; 2012—$2,369)	3,875	3,373
Other invested assets	66	68
Total investments	12,933	12,534
Cash and cash equivalents	382	487
Investment income receivable	116	115
Finance receivable	79	75
Premiums receivable	1,350	1,214
Reinsurance recoverable	582	615
Prepaid reinsurance premiums	26	26
Deferred policy acquisition costs	546	470
Land, building and equipment, net, for company use (accumulated depreciation: 2013—$405; 2012—$397)	213	217
Other assets	94	61
Separate accounts	713	734
Total assets	17,034	16,548
Insurance reserves
Loss and loss expense reserves	4,284	4,230
Life policy and investment contract reserves	2,345	2,295
Unearned premiums	1,947	1,792
Other liabilities	597	660
Deferred income tax	512	453
Note payable	104	104
Long-term debt and capital lease obligations	833	827
Separate accounts	713	734
Total liabilities	11,335	11,095
Commitments and contingent liabilities (Note 12)	0	0
SHAREHOLDERS' EQUITY
Common stock, par value—$2 per share; (authorized: 2013 and 2012—500 million shares; issued and outstanding: 2013—198 million shares and 2012—197 million shares)	396	394
Paid-in capital	1,162	1,134
Retained earnings	4,152	4,021
Accumulated other comprehensive income	1,221	1,129
Treasury stock at cost (2013 and 2012—34 million shares)	(1,232)	(1,225)
Total shareholders' equity	5,699	5,453
Total liabilities and shareholders' equity	$ 17,034	$ 16,548