Investments in Affiliates (Tables)

12 Months Ended

Dec. 31, 2012

Schedule of Equity Method Investments [Line Items]

Investments in affiliates

(U.S. dollars in thousands)	2012		2011
Investment fund affiliates	$	845,197	$	768,851
Operating affiliates		281,678		283,878
Total investment affiliates	$	1,126,875	$	1,052,729

Investment fund affiliates

Schedule of Equity Method Investments [Line Items]

Investments in affiliates

		XL Group Investment						Combined
				Equity in		Weighted		Funds
				Net Income		Average XL		Total Net
Year Ended December 31, 2012		Carrying		(Loss) for		Percentage		Assets
(U.S. dollars in thousands, except percentages)		Value		the Year		Ownership		(Estimated) (2)
Alternative Funds (1):
	Arbitrage	$	131,037	$	7,149		3.7%	$	3,517,404
	Directional		297,535		14,791		5.9%		5,057,381
	Event Driven (3)		198,282		13,125		2.4%		8,272,227
	Multi-Style		326		(99)		13.5%		2,410
	Total alternative funds	$	627,180	$	34,966		3.7%	$	16,849,422
Private Investment Funds (1):			218,017		23,538		17.1%		1,275,543
	Total Investment Fund Affiliates	$	845,197	$	58,504		4.7%	$	18,124,965
Year Ended December 31, 2011
Alternative Funds (1):
	Arbitrage	$	123,969	$	1,291		3.4%	$	3,678,904
	Directional		217,779		9,154		6.0%		3,619,272
	Event Driven		229,956		(60)		3.1%		7,472,680
	Multi-Style		425		(9)		17.6%		2,410
	Total alternative funds	$	572,129	$	10,376		3.9%	$	14,773,266
Private Investment Funds (1):			196,722		15,877		5.1%		3,820,497
	Total Investment Fund Affiliates	$	768,851	$	26,253		4.1%	$	18,593,763

_______________

(1)The Company generally records its alternative fund affiliates on a one-month lag and its private investment fund affiliates on a three-month lag.

(2)Total estimated net assets are generally as at November 30 and September 30, respectively.

(3)The Company accounts for its investment in certain funds where the ownership percentage is less than three percent using the equity method, where the Company has significant influence over the related investment management company.

Operating affiliates

Schedule of Equity Method Investments [Line Items]

Investments in affiliates

					Combined Investee
	XL Group Investment				Summarized Financial Data (Estimated) (1)
			Equity in
			Net Income						Total		Net
Year ended December 31, 2012	Carrying		(Loss) for		Total		Total		Revenue		Income
(U.S. dollars in thousands)	Value		the Year		Assets		Liabilities		(Loss)		(Loss)
Financial operating affiliates	$	732	$	-	$	12,711,762	$	12,678,810	$	20,467	$	6,183
Other strategic operating affiliates		192,792		27,033		2,094,539		1,512,551		698,665		51,702
Investment manager affiliates		88,154		28,777		610,940		37,699		364,551		274,312
Total operating affiliates	$	281,678	$	55,810	$	15,417,241	$	14,229,060	$	1,083,683	$	332,197
Year ended December 31, 2011
Financial operating affiliates	$	732	$	(1,018)	$	11,957,534	$	11,931,662	$	12,564	$	1,115
Other strategic operating affiliates		153,955		20,891		1,295,921		967,264		348,831		48,641
Investment manager affiliates (2)		129,191		56,913		601,511		38,349		319,984		222,260
Total operating affiliates	$	283,878	$	76,786	$	13,854,966	$	12,937,275	$	681,379	$	272,016

_______________

(1)The Company generally records its operating affiliates on a three month lag. Estimated assets and liabilities are generally at September 30, 2012 and 2011, respectively.

(2)During the year ended December 31, 2012 and 2011 the Company received distributions from its Investment Manager Affiliates of approximately $58.3 million and $23.2 million respectively.  During 2011 the Company sold its interests in Finisterre for total proceeds of $35.0 million as explained below at “Investment Manager Affiliates.”