Condensed Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Investments
Fixed maturities, at fair value (amortized cost: 2013—$8,502; 2012—$8,222)	$ 9,038	$ 9,093
Equity securities, at fair value (cost: 2013—$2,471; 2012—$2,369)	3,984	3,373
Other invested assets	68	68
Total investments	13,090	12,534
Cash and cash equivalents	511	487
Investment income receivable	115	115
Finance receivable	79	75
Premiums receivable	1,393	1,214
Reinsurance recoverable	584	615
Prepaid reinsurance premiums	26	26
Deferred policy acquisition costs	576	470
Land, building and equipment, net, for company use (accumulated depreciation: 2013—$412; 2012—$397)	211	217
Other assets	54	61
Separate accounts	700	734
Total assets	17,339	16,548
Insurance reserves
Loss and loss expense reserves	4,307	4,230
Life policy and investment contract reserves	2,373	2,295
Unearned premiums	2,026	1,792
Other liabilities	639	660
Deferred income tax	542	453
Note payable	104	104
Long-term debt and capital lease obligations	832	827
Separate accounts	700	734
Total liabilities	11,523	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	1,177	1,134
Retained earnings	4,214	4,021
Accumulated other comprehensive income	1,267	1,129
Treasury stock at cost (2013 and 2012—34 million shares)	(1,238)	(1,225)
Total shareholders' equity	5,816	5,453
Total liabilities and shareholders' equity	$ 17,339	$ 16,548