UNAUDITED CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Revenues:
Net premiums earned	$ 1,529,691	$ 1,436,418
Net investment income	246,469	265,242
Realized investment gains (losses):
Net realized gains (losses) on investments sold	41,147	41,768
Other-than-temporary impairments on investments	(3,727)	(18,565)
Other-than-temporary impairments on investments transferred to (from) other comprehensive income	(910)	(2,400)
Net realized gains (losses) on investments	36,510	20,803
Net realized and unrealized gains (losses) on derivative instruments	7,885	702
Income (loss) from investment fund affiliates	32,221	19,408
Fee income and other	9,632	9,859
Total revenues	1,862,408	1,752,432
Expenses:
Net losses and loss expenses incurred	843,084	854,065
Claims and policy benefits	110,954	121,307
Acquisition costs	220,259	224,151
Operating expenses	283,833	282,411
Exchange (gains) losses	(33,435)	12,718
Interest expense	38,700	39,298
Total expenses	1,463,395	1,533,950
Income (loss) before income tax and income (loss) from operating affiliates	399,013	218,482
Income (loss) from operating affiliates	30,998	16,253
Provision (benefit) for income tax	43,479	21,550
Net income (loss)	386,532	213,185
Non-controlling interests	(35,742)	(36,557)
Net income (loss) attributable to XL Group plc and ordinary shareholders	$ 350,790	$ 176,628
Weighted average ordinary shares and ordinary share equivalents outstanding - basic (in shares)	295,000	315,120
Weighted average ordinary shares and ordinary share equivalents outstanding - diluted (in shares)	299,469	317,639
Earnings (loss) per ordinary share and ordinary share equivalent - basic (in dollars per share)	$ 1.19	$ 0.56
Earnings (loss) per ordinary share and ordinary share equivalent - diluted (in dollars per share)	$ 1.17	$ 0.56