Guarantor Financial Information Income Statement (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2016		Sep. 30, 2015	Sep. 30, 2016		Sep. 30, 2015
Revenues:
Net premiums earned		$ 2,434,037		$ 2,423,552	$ 7,320,859		$ 5,839,605
Net investment income		209,771		225,146	631,045		656,863
Total net realized gains (losses) on investments		143,676		51,407	341,043		154,265
Net realized and unrealized gains (losses) on derivative instruments		5,490		(7,903)	2,774		57,127
Income (loss) from investment fund affiliates		12,156		(3,715)	20,756		62,991
Fee income and other		8,600		7,355	27,724		23,095
Total revenues		2,588,120		2,569,702	7,652,769		6,677,613
Expenses:
Net losses and loss expenses incurred		1,491,803		1,464,285	4,506,674		3,385,307
Claims and policy benefits		5,875		22,579	16,294		64,047
Acquisition costs	[1]	403,888		409,173	1,227,675		904,486
Operating expenses		508,458		570,142	1,546,360		1,403,152
Exchange (gains) losses		(1,695)		11,661	(54,614)		49,425
Loss (gain) on sale of subsidiary		(3,670)		0	(3,670)		0
Interest expense		49,445		51,929	157,486		153,034
Total expenses		2,454,104		2,529,769	7,396,205		5,959,451
Income (loss) before income tax and income (loss) from operating affiliates		134,016		39,933	256,564		718,162
Income (loss) from operating affiliates		12,410		8,196	46,478		40,326
Gain on sale of operating affiliate		0		0	0		340,407
Equity in net earnings (losses) of subsidiaries		0		0	0		0
Provision (benefit) for income tax		17,749		(37,042)	42,511		20,135
Net income (loss)		128,677		85,171	260,531		1,078,760
Non-controlling interests		58,076		57,889	124,263		100,158
Net income (loss) attributable to ordinary shareholders		70,601		27,282	136,268		978,602
Comprehensive income (loss)		181,819		(93,810)	969,457		449,226
Life Funds Withheld Assets
Revenues:
Net investment income		38,937		46,586	119,643		143,869
Net realized and unrealized gains (losses) on derivative instruments		(225,610)		(126,140)	(691,432)		(116,333)
Consolidating Adjustments and Eliminations
Revenues:
Net premiums earned		0		0	0		0
Net investment income		910		598	1,896		2,711
Total net realized gains (losses) on investments		49		(9,999)	1,949		(8,735)
Net realized and unrealized gains (losses) on derivative instruments		0		0	0		0
Income (loss) from investment fund affiliates		0		0	0		0
Fee income and other		0		0	0		0
Total revenues		959		(9,401)	3,845		(6,024)
Expenses:
Net losses and loss expenses incurred		0		0	0		0
Claims and policy benefits		0		0	0		0
Acquisition costs		0		0	0		0
Operating expenses		0		0	0		0
Exchange (gains) losses		0		0	0		0
Loss (gain) on sale of subsidiary		0			0
Interest expense		0		0	0		0
Total expenses		0		0	0		0
Income (loss) before income tax and income (loss) from operating affiliates		959		(9,401)	3,845		(6,024)
Income (loss) from operating affiliates		0		0	0		0
Gain on sale of operating affiliate		0		0	0		0
Equity in net earnings (losses) of subsidiaries		(254,725)		(184,362)	(494,796)		(2,191,969)
Provision (benefit) for income tax		0		0	0		0
Net income (loss)		(253,766)		(193,763)	(490,951)		(2,197,993)
Non-controlling interests		(75)		(20)	(251)		(154)
Net income (loss) attributable to ordinary shareholders		(253,691)		(193,743)	(490,700)		(2,197,839)
Comprehensive income (loss)		(476,127)		48,441	(2,157,078)		(1,139,087)
Consolidating Adjustments and Eliminations | Life Funds Withheld Assets
Revenues:
Net realized and unrealized gains (losses) on derivative instruments		0		0	0		0
XL- Bermuda/Ireland
Revenues:
Net premiums earned		0	[2]	0	0	[2]	0
Net investment income		75	[2]	20	251	[2]	154
Total net realized gains (losses) on investments		0	[2]	0	0	[2]	0
Net realized and unrealized gains (losses) on derivative instruments		0	[2]	0	0	[2]	0
Income (loss) from investment fund affiliates		0	[2]	0	0	[2]	0
Fee income and other		0	[2]	0	0	[2]	0
Total revenues		75	[2]	20	251	[2]	154
Expenses:
Net losses and loss expenses incurred		0	[2]	0	0	[2]	0
Claims and policy benefits		0	[2]	0	0	[2]	0
Acquisition costs		0	[2]	0	0	[2]	0
Operating expenses		19,979	[2]	34,514	22,753	[2]	40,230
Exchange (gains) losses		(180)	[2]	(16)	(633)	[2]	(287)
Loss (gain) on sale of subsidiary	[2]	0			0
Interest expense		10	[2]	9	(5)	[2]	11
Total expenses		19,809	[2]	34,507	22,115	[2]	39,954
Income (loss) before income tax and income (loss) from operating affiliates		(19,734)	[2]	(34,487)	(21,864)	[2]	(39,800)
Income (loss) from operating affiliates		0	[2]	0	0	[2]	0
Gain on sale of operating affiliate		0	[2]	0	0	[2]	0
Equity in net earnings (losses) of subsidiaries		90,335	[2]	61,769	157,512	[2]	1,018,186
Provision (benefit) for income tax		0	[2]	0	(620)	[2]	(216)
Net income (loss)		70,601	[2]	27,282	136,268	[2]	978,602
Non-controlling interests		0	[2]	0	0	[2]	0
Net income (loss) attributable to ordinary shareholders		70,601	[2]	27,282	136,268	[2]	978,602
Comprehensive income (loss)		181,819	[2]	(93,810)	969,457	[2]	449,226
XL- Bermuda/Ireland | Life Funds Withheld Assets
Revenues:
Net realized and unrealized gains (losses) on derivative instruments		0	[2]	0	0	[2]	0
XL-Cayman
Revenues:
Net premiums earned		0		0	0		0
Net investment income		2,463		2,522	7,344		8,222
Total net realized gains (losses) on investments		370		10,291	1,623		14,092
Net realized and unrealized gains (losses) on derivative instruments		0		0	0		12,365
Income (loss) from investment fund affiliates		0		0	0		0
Fee income and other		0		0	0		0
Total revenues		2,833		12,813	8,967		34,679
Expenses:
Net losses and loss expenses incurred		0		0	0		0
Claims and policy benefits		0		0	0		0
Acquisition costs		0		0	0		0
Operating expenses		5,625		2,289	8,191		7,731
Exchange (gains) losses		32		135	(140)		117
Loss (gain) on sale of subsidiary		0			0
Interest expense		35,320		35,623	105,666		108,097
Total expenses		40,977		38,047	113,717		115,945
Income (loss) before income tax and income (loss) from operating affiliates		(38,144)		(25,234)	(104,750)		(81,266)
Income (loss) from operating affiliates		0		0	0		0
Gain on sale of operating affiliate		0		0	0		0
Equity in net earnings (losses) of subsidiaries		164,390		122,593	337,284		1,173,783
Provision (benefit) for income tax		0		0	0		245
Net income (loss)		126,246		97,359	232,534		1,092,272
Non-controlling interests		35,911		35,590	75,022		74,086
Net income (loss) attributable to ordinary shareholders		90,335		61,769	157,512		1,018,186
Comprehensive income (loss)		201,553		(59,323)	990,701		488,810
XL-Cayman | Life Funds Withheld Assets
Revenues:
Net realized and unrealized gains (losses) on derivative instruments		0		0	0		0
Other XL Subsidiaries
Revenues:
Net premiums earned		2,434,037		2,423,552	7,320,859		5,839,605
Net investment income		206,323		222,006	621,554		645,776
Total net realized gains (losses) on investments		143,257		51,115	337,471		148,908
Net realized and unrealized gains (losses) on derivative instruments		5,490		(7,903)	2,774		44,762
Income (loss) from investment fund affiliates		12,156		(3,715)	20,756		62,991
Fee income and other		8,600		7,355	27,724		23,095
Total revenues		2,584,253		2,566,270	7,639,706		6,648,804
Expenses:
Net losses and loss expenses incurred		1,491,803		1,464,285	4,506,674		3,385,307
Claims and policy benefits		5,875		22,579	16,294		64,047
Acquisition costs		403,888		409,173	1,227,675		904,486
Operating expenses		482,854		533,339	1,515,416		1,355,191
Exchange (gains) losses		(1,547)		11,542	(53,841)		49,595
Loss (gain) on sale of subsidiary		(3,670)			(3,670)
Interest expense		14,115		16,297	51,825		44,926
Total expenses		2,393,318		2,457,215	7,260,373		5,803,552
Income (loss) before income tax and income (loss) from operating affiliates		190,935		109,055	379,333		845,252
Income (loss) from operating affiliates		12,410		8,196	46,478		40,326
Gain on sale of operating affiliate		0		0	0		340,407
Equity in net earnings (losses) of subsidiaries		0		0	0		0
Provision (benefit) for income tax		17,749		(37,042)	43,131		20,106
Net income (loss)		185,596		154,293	382,680		1,205,879
Non-controlling interests		22,240		22,319	49,492		26,226
Net income (loss) attributable to ordinary shareholders		163,356		131,974	333,188		1,179,653
Comprehensive income (loss)		274,574		10,882	1,166,377		650,277
Other XL Subsidiaries | Life Funds Withheld Assets
Revenues:
Net realized and unrealized gains (losses) on derivative instruments		$ (225,610)		$ (126,140)	$ (691,432)		$ (116,333)

[1] The Company has reflected the amortization of certain fair value adjustments recorded in conjunction with the Catlin Acquisition within the respective segments.

[2] Results for the period include XL-Ireland, which prior to the Redomestication was the ultimate parent and is now in liquidation proceedings as outlined in Note 1, "Basis of Preparation and Consolidation." The Company expects the net assets of XL-Ireland to ultimately be distributed to XL-Bermuda upon completion of the liquidation.