CONSOLIDATED STATEMENTS OF CASH FLOW (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Operating Activities
Net income	$ 293,086	$ 608,476
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized gains	(100,982)	(184,423)
Net impairment losses recognized in earnings	7,103	8,091
Equity in net (income) loss of investment funds accounted for using the equity method and other income	50,324	(29,925)
Share-based compensation	25,286	25,450
Changes in:
Reserve for losses and loss adjustment expenses, net of unpaid losses and loss adjustment expense recoverable	334,620	212,024
Unearned premiums, net of prepaid reinsurance premiums	204,042	105,905
Premiums receivable	(114,044)	(73,654)
Deferred acquisition costs, net	(29,146)	(17,570)
Reinsurance balances payable	(3,381)	(22,255)
Other liabilities	12,678	8,143
Other items, net	76,885	17,299
Net Cash Provided By Operating Activities	756,471	657,561
Investing Activities
Purchases of fixed maturity investments	(10,116,781)	(14,501,938)
Purchase of equity securities	(343,062)	(139,165)
Purchases of other investments	(373,814)	(376,405)
Proceeds from the sales of fixed maturity investments	8,855,624	13,984,442
Proceeds from the sales of equity securities	311,117	55,919
Proceeds from the sales of other investments	396,514	245,889
Proceeds from redemptions and maturities of fixed maturity investments	738,081	683,826
Net purchases of short-term investments	112,465	(212,093)
Change in investment of securities lending collateral	3,325	9,705
Purchases of furniture, equipment and other assets	(15,526)	(10,111)
Net Cash Used By Investing Activities	(432,057)	(259,931)
Financing Activities
Purchases of common shares under share repurchase program	(287,558)	(503,724)
Proceeds from common shares issued, net	3,087	22,956
Proceeds from borrowings	0	264,526
Repayments of borrowings	(11,839)	(125,985)
Change in securities lending collateral	(3,325)	(9,705)
Other	3,999	8,950
Preferred dividends paid	(19,383)	(19,383)
Net Cash Used For Financing Activities	(315,019)	(362,365)
Effects of exchange rate changes on foreign currency cash	(2,240)	(3,839)
Increase (decrease) in cash	7,155	31,426
Cash beginning of year	362,740	334,571
Cash end of period	$ 369,895	$ 365,997