Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Investments:
Fixed maturity securities	$ 11,312,037	$ 11,209,154
Equity securities available for sale	443,439	561,053
Arbitrage trading account	397,312	359,192
Investment funds	680,638	512,411
Loans receivable	263,187	353,583
Real estate	342,905	0
Total investments	13,439,518	12,995,393
Cash and cash equivalents	911,742	642,952
Premiums and fees receivable	1,206,204	1,087,208
Due from reinsurers	1,215,679	1,070,256
Accrued investment income	133,776	138,384
Prepaid reinsurance premiums	258,271	215,816
Deferred policy acquisition costs	448,795	405,942
Property, furniture and equipment	262,275	254,720
Deferred federal and foreign income taxes	0	65,492
Goodwill	90,832	90,581
Trading account receivable from brokers and clearing organizations	318,240	339,235
Current federal and foreign income taxes	9,670	23,605
Other assets	192,729	198,963
Total assets	18,487,731	17,528,547
Liabilities:
Reserves for losses and loss expenses	9,337,134	9,016,549
Unearned premiums	2,189,575	1,953,721
Due to reinsurers	241,204	215,723
Trading account securities sold but not yet purchased	62,514	53,494
Deferred federal and foreign income taxes	31,623	0
Other liabilities	866,229	836,001
Junior subordinated debentures	242,997	242,784
Senior notes and other debt	1,500,503	1,500,419
Total liabilities	14,471,779	13,818,691
Equity:
Preferred stock, par value $.10 per share: Authorized 5,000,000 shares; issued and outstanding - none	0	0
Common stock, par value $.20 per share: Authorized 500,000,000 shares, issued and outstanding, net of treasury shares, 137,520,019 and 141,009,834 shares	47,024	47,024
Additional paid-in capital	941,109	935,099
Retained earnings	4,546,232	4,194,684
Accumulated other comprehensive income	354,851	276,563
Treasury stock, at cost, 97,597,899 and 94,108,084 shares	(1,880,790)	(1,750,494)
Total common stockholders' equity	4,008,426	3,702,876
Noncontrolling interests	7,526	6,980
Total equity	4,015,952	3,709,856
Total liabilities and equity	$ 18,487,731	$ 17,528,547