Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Investments:
Fixed maturity securities	$ 11,554,209	$ 11,312,037
Equity securities available for sale	489,220	443,439
Arbitrage trading account	344,892	397,312
Investment funds	679,689	680,638
Loans receivable	357,121	263,187
Real estate	355,254	342,905
Total investments	13,780,385	13,439,518
Cash and cash equivalents	1,082,407	911,742
Premiums and fees receivable	1,307,237	1,206,204
Due from reinsurers	1,242,270	1,215,679
Accrued investment income	132,745	133,776
Prepaid reinsurance premiums	274,706	258,271
Deferred policy acquisition costs	377,600	364,937
Real estate, furniture and equipment	268,229	262,275
Goodwill	90,172	90,172
Trading account receivables from brokers and clearing organizations	382,479	318,240
Current federal and foreign income taxes	0	9,670
Other assets	195,402	193,389
Total assets	19,133,632	18,403,873
Liabilities:
Reserves for losses and loss expenses	9,394,152	9,337,134
Unearned premiums	2,311,187	2,189,575
Due to reinsurers	268,288	241,204
Trading account securities sold but not yet purchased	71,386	62,514
Current federal and foreign income taxes	53,046	0
Deferred federal and foreign income taxes	1,701	2,835
Other liabilities	801,855	866,229
Junior subordinated debentures	243,050	242,997
Senior notes and other debt	1,853,512	1,500,503
Total liabilities	14,998,177	14,442,991
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, 138,274,272 and 137,520,019 shares	47,024	47,024
Additional paid-in capital	938,417	941,109
Retained earnings	4,615,439	4,491,162
Accumulated other comprehensive income	393,259	354,851
Treasury stock, at cost, 96,843,646 and 97,597,899 shares	(1,867,223)	(1,880,790)
Total stockholders' equity	4,126,916	3,953,356
Noncontrolling interests	8,539	7,526
Total equity	4,135,455	3,960,882
Total liabilities and equity	$ 19,133,632	$ 18,403,873