Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2011

Fair Value, by Balance Sheet Grouping [Table Text Block]

September 30, 2011 (U.S. dollars in thousands) (Unaudited)	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Collateral and Counterparty Netting			Balance at September 30, 2011
Assets
U.S. Government and Government-Related/Supported	$	—	$	2,108,841	$	—	$	—		$	2,108,841
Corporate (1)		—		10,753,121		4,787		—			10,757,908
Residential mortgage-backed securities – Agency		—		5,579,956		15,183		—			5,595,139
Residential mortgage-backed securities – Non-Agency		—		680,182		2,799		—			682,981
Commercial mortgage-backed securities		—		1,012,492		4,394		—			1,016,886
Collateralized debt obligations		—		7,733		665,842		—			673,575
Other asset-backed securities		—		1,059,713		17,112		—			1,076,825
U.S. States and political subdivisions of the States		—		1,723,554		—		—			1,723,554
Non-U.S. Sovereign Government, Supranational and Government-Related		—		3,369,641		—		—			3,369,641
Total fixed maturities, at fair value	$	—	$	26,295,233	$	710,117	$	—		$	27,005,350
Equity securities, at fair value (2)		229,631		179,532		—		—			409,163
Short-term investments, at fair value (1)(3)		—		366,679		—		—			366,679
Total investments available for sale	$	229,631	$	26,841,444	$	710,117	$			$	27,781,192
Cash equivalents (4)		1,534,055		739,057		—		—			2,273,112
Other investments (5)		—		562,490		114,362		—			676,852
Other assets (6)(7)		—		201,470		104		(56,079	)		145,495
Total assets accounted for at fair value	$	1,763,686	$	28,344,461	$	824,583	$	(56,079	)	$	30,876,651
Liabilities
Financial instruments sold, but not yet purchased (8)	$	—	$	26,363	$	—	$	—		$	26,363
Other liabilities (6)(7)		—		19,558		52,093		(2,050	)		69,601
Total liabilities accounted for at fair value	$	—	$	45,921	$	52,093	$	(2,050	)	$	95,964

December 31, 2010 (U.S. dollars in thousands)	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Collateral and Counterparty Netting			Balance at December 31, 2010
Assets
U.S. Government and Government-Related/Supported	$	—	$	2,565,444	$	—	$	—		$	2,565,444
Corporate (1)		—		10,932,105		36,866		—			10,968,971
Residential mortgage-backed securities – Agency		—		5,173,456		30,255		—			5,203,711
Residential mortgage-backed securities – Non-Agency		—		1,016,859		4,964		—			1,021,823
Commercial mortgage-backed securities		—		1,170,884		1,623		—			1,172,507
Collateralized debt obligations		—		12,566		721,572		—			734,138
Other asset-backed securities		—		935,882		24,650		—			960,532
U.S. States and political subdivisions of the States		—		1,360,456		—		—			1,360,456
Non-U.S. Sovereign Government, Supranational and Government-Related		—		3,150,856		3,667		—			3,154,523
Total fixed maturities, at fair value	$	—	$	26,318,508	$	823,597	$	—		$	27,142,105
Equity securities, at fair value (2)		71,284		13,483		—		—			84,767
Short-term investments, at fair value (1)(3)		—		450,681		—		—			450,681
Total investments available for sale	$	71,284	$	26,782,672	$	823,597	$	—		$	27,677,553
Cash equivalents (4)		1,358,619		540,646		—		—			1,899,265
Other investments (5)		—		490,320		133,717		—			624,037
Other assets (6)(7)		—		108,056		7,882		(22,995	)		92,943
Total assets accounted for at fair value	$	1,429,903	$	27,921,694	$	965,196	$	(22,995	)	$	30,293,798
Liabilities
Financial instruments sold, but not yet purchased (8)	$	256	$	21,270	$	—	$	—		$	21,526
Other liabilities (6)(7)		—		13,591		47,077		—			60,668
Total liabilities accounted for at fair value	$	256	$	34,861	$	47,077	$	—		$	82,194

Fair Value, Assets And Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Text Block]

	Level 3 Assets and Liabilities Three Months Ended September 30, 2011
(U.S. dollars in thousands) (Unaudited)	Corporate			Residential mortgage-backed securities – Agency			Residential mortgage-backed securities – Non Agency			Commercial mortgage-backed securities			Collateralized debt obligations
Balance, beginning of period	$	4,786		$	15,385		$	3,194		$	4,563		$	727,239
Realized gains (losses)		23			(81	)		(328	)		(501	)		(2,662	)
Movement in unrealized gains (losses)		(22	)		52			76			564			(46,520	)
Purchases and issuances		—			33			—			—			—
Sales and settlements		—			(206	)		(143	)		(232	)		(12,215	)
Transfers into Level 3		—			—			—			—			—
Transfers out of Level 3		—			—			—			—			—
Fixed maturities to short-term investments classification change		—			—			—			—			—
Balance, end of period	$	4,787		$	15,183		$	2,799		$	4,394		$	665,842
Movement in total gains (losses) above relating to instruments still held at the reporting date	$	1		$	(29	)	$	(252	)	$	63		$	(49,432	)

	Level 3 Assets and Liabilities Three Months Ended September 30, 2011 (Continued)
(U.S. dollars in thousands) (Unaudited)	Other asset backed securities			Non-U.S. Sovereign Government and Supranationals and Government- Related		Short-term Investments		Other investments			Derivative Contracts - Net
Balance, beginning of period	$	17,048		$	—	$	—	$	114,540		$	(49,645	)
Realized gains (losses)		(238	)		—		—		(244	)		—
Movement in unrealized gains (losses)		302			—		—		2,642			(2,344	)
Purchases and issuances		—			—		—		1,667			—
Sales and settlements		—			—		—		(4,243	)		—
Transfers into Level 3		—			—		—		—			—
Transfers out of Level 3		—			—		—		—			—
Fixed maturities to short-term investments classification change		—			—		—		—			—
Balance, end of period	$	17,112		$	—	$	—	$	114,362		$	(51,989	)
Movement in total gains (losses) above relating to instruments still held at the reporting date	$	64		$	—	$	—	$	2,398		$	(2,344	)

	Level 3 Assets and Liabilities Nine Months Ended September 30, 2011
(U.S. dollars in thousands) (Unaudited)	Corporate			Residential mortgage-backed securities – Agency			Residential mortgage-backed securities – Non Agency			Commercial mortgage-backed securities			Collateralized debt obligations
Balance, beginning of period	$	36,866		$	30,255		$	4,964		$	1,623		$	721,572
Realized gains (losses)		(257	)		(81	)		(329	)		(1,179	)		(3,733	)
Movement in unrealized gains (losses)		173			2			61			1,078			(10,104	)
Purchases and issuances		6,878			33			—			3,155			2,379
Sales and settlements		(10,049	)		(492	)		(517	)		(283	)		(46,158	)
Transfers into Level 3		—			—			—			—			1,886
Transfers out of Level 3		(28,824	)		(14,534	)		(1,380	)		—			—
Fixed maturities to short-term investments classification change		—			—			—			—			—
Balance, end of period	$	4,787		$	15,183		$	2,799		$	4,394		$	665,842
Movement in total gains (losses) above relating to instruments still held at the reporting date	$	(52	)	$	(79	)	$	(268	)	$	(855	)	$	(15,656	)

	Level 3 Assets and Liabilities Nine Months Ended September 30, 2011 (Continued)
(U.S. dollars in thousands) (Unaudited)	Other asset backed securities			Non-U.S. Sovereign Government and Supranationals and Government- Related			Short-term Investments		Other investments			Derivative Contracts - Net
Balance, beginning of period	$	24,650		$	3,667		$	—	$	133,717		$	(39,195	)
Realized gains (losses)		(555	)		—			—		11,911			—
Movement in unrealized gains (losses)		7,162			—			—		10,134			(12,620	)
Purchases and issuances		—			—			—		9,782			—
Sales and settlements		(9,114	)		—			—		(51,182	)		(174	)
Transfers into Level 3		—			—			—		—			—
Transfers out of Level 3		(5,031	)		(3,667	)		—		—			—
Fixed maturities to short-term investments classification change		—			—			—		—			—
Balance, end of period	$	17,112		$	—		$	—	$	114,362		$	(51,989	)
Movement in total gains (losses) above relating to instruments still held at the reporting date	$	6,287		$	—		$	—	$	19,735		$	(12,620	)

	Level 3 Assets and Liabilities Three Months Ended September 30, 2010
(U.S. dollars in thousands) (Unaudited)	Corporate			Residential mortgage-backed securities – Agency			Residential mortgage-backed securities – Non Agency			Commercial mortgage-backed securities		Collateralized debt obligations
Balance, beginning of period	$	40,618		$	1,226		$	10,008		$	427	$	690,906
Realized gains (losses)		(3	)		(6	)		(385	)		—		(5,520	)
Movement in unrealized gains (losses)		338			39			(41	)		3		46,999
Purchases and issuances		2,400			6,740			—			—		—
Sales and settlements		(1,282	)		—			(6	)		—		(11,825	)
Transfers into Level 3		—			—			—			—		—
Transfers out of Level 3		(30,762	)		—			(4,518	)		—		(28,651	)
Fixed maturities to short-term investments classification change		—			—			—			—		—
Balance, end of period	$	11,309		$	7,999		$	5,058		$	430	$	691,909
Movement in total gains (losses) above relating to instruments still held at the reporting date	$	338		$	40		$	(37	)	$	3	$	46,685

	Level 3 Assets and Liabilities Three Months Ended September 30, 2010 (Continued)
(U.S. dollars in thousands) (Unaudited)	Other asset backed securities			Non-U.S. Sovereign Government and Supranationals and Government- Related		Short-term Investments		Other investments			Derivative Contracts - Net
Balance, beginning of period	$	22,521		$	3,182	$	—	$	92,857		$	162,911
Realized gains (losses)		(7,515	)		—		—		1,294			—
Movement in unrealized gains (losses)		5,643			307		—		234			32,567
Purchases and issuances		10,714			—		—		664			—
Sales and settlements		—			—		—		(12,489	)		(1,516	)
Transfers into Level 3		—			—		—		—			—
Transfers out of Level 3		(1	)		—		—		—			—
Fixed maturities to short-term investments classification change		—			—		—		—			—
Balance, end of period	$	31,362		$	3,489	$	—	$	82,560		$	193,962
Movement in total gains (losses) above relating to instruments still held at the reporting date	$	(2,006	)	$	307	$	—	$	234		$	32,567

	Level 3 Assets and Liabilities Nine Months Ended September 30, 2010
(U.S. dollars in thousands) (Unaudited)	Corporate			Residential mortgage-backed securities – Agency			Residential mortgage-backed securities – Non Agency			Commercial mortgage-backed securities			Collateralized debt obligations
Balance, beginning of period	$	10,311		$	7,894		$	42,190		$	2,755		$	197,149
Realized gains (losses)		(4,315	)		—			(46	)		(209	)		(17,498	)
Movement in unrealized gains (losses)		393			39			104			29			76,655
Purchases and issuances		1,265			7,949			—			—			—
Sales and settlements		(519	)		—			(2,294	)		(707	)		(16,614	)
Transfers into Level 3		8,115			—			4,044			—			475,548
Transfers out of Level 3		(3,941	)		(7,883	)		(38,940	)		(1,438	)		(23,331	)
Fixed maturities to short-term investments classification change		—			—			—			—			—
Balance, end of period	$	11,309		$	7,999		$	5,058		$	430		$	691,909
Movement in total gains (losses) above relating to instruments still held at the reporting date	$	576		$	39		$	(56	)	$	(136	)	$	72,239

	Level 3 Assets and Liabilities Nine Months Ended September 30, 2010 (Continued)
(U.S. dollars in thousands) (Unaudited)	Other asset backed securities			Non-U.S. Sovereign Government and Supranationals and Government- Related		Short-term Investments		Other investments			Derivative Contracts - Net
Balance, beginning of period	$	38,179		$	3,217	$	—	$	75,584		$	100,515
Realized gains (losses)		(19,018	)		—		—		3,860			—
Movement in unrealized gains (losses)		14,757			32		—		5,785			84,202
Purchases and issuances		12,978			—		—		11,575			10,985
Sales and settlements		(1,504	)		—		—		(14,244	)		(1,740	)
Transfers into Level 3		204			240		—		—			—
Transfers out of Level 3		(14,234	)		—		—		—			—
Fixed maturities to short-term investments classification change		—			—		—		—			—
Balance, end of period	$	31,362		$	3,489	$	—	$	82,560		$	193,962
Movement in total gains (losses) above relating to instruments still held at the reporting date	$	7,642		$	32	$	—	$	5,785		$	84,202

Schedule Of Financial Instruments Not Carried at Fair Value [Text Block]

	(Unaudited) September 30, 2011				December 31, 2010
(U.S. dollars in thousands)	Carrying Value		Fair Value		Carrying Value		Fair Value
Fixed maturities, held to maturity	$	2,725,623	$	2,901,434	$	2,728,335	$	2,742,626
Other investments – structured transactions	$	324,723	$	316,781	$	327,686	$	317,524
Financial Assets	$	3,050,346	$	3,218,215	$	3,056,021	$	3,060,150
Deposit liabilities	$	1,636,602	$	1,760,445	$	1,684,606	$	1,737,107
Notes payable and debt		2,281,335		2,305,867		2,464,410		2,627,897
Financial Liabilities	$	3,917,937	$	4,066,312	$	4,149,016	$	4,365,004
Non-controlling interest - Redeemable Series C preference ordinary shares	$	—	$	—	$	71,900	$	61,115