Sale of Life Reinsurance Subsidiary (Details) (USD $)	3 Months Ended		6 Months Ended			0 Months Ended			3 Months Ended		6 Months Ended		3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	May 01, 2014 XL Re Life (SAC) Ltd [Member]	May 30, 2014 XL Re Life (SAC) Ltd [Member]	May 30, 2014 Life Insurance Product Line [Member] XL Re Life (SAC) Ltd [Member]	Jun. 30, 2014 Life Funds Withheld Assets	Jun. 30, 2013 Life Funds Withheld Assets	Jun. 30, 2014 Life Funds Withheld Assets	Jun. 30, 2013 Life Funds Withheld Assets	Jun. 30, 2014 Life Funds Withheld Assets XL Re Life (SAC) Ltd [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of Subsidiary Stock, Percentage						100.00%
Disposal Group, Including Discontinued Operation, Consideration						$ 570,000,000
Quota Share Reinsurance Percentage						100.00%
Future policy benefit reserves	5,273,549,000		5,273,549,000		4,803,816,000			5,200,000,000
Estimated Future Policy Benefit Reserve Retention							400,000,000
Future policy benefit reserves recoverable	4,823,680,000		4,823,680,000		0		4,800,000,000
Estimated Assets Funds Withheld							5,700,000,000
Pro Forma Effect of Sale, After Tax Net Loss						621,300,000
Underwriting Profit Loss	135,074,000	39,792,000	232,305,000	168,174,000									0
Net investment income	232,773,000	232,546,000	465,962,000	479,014,000					19,165,000	0	19,165,000	0	19,165,000
Net realized gains (losses) on investments sold									624,000	0	624,000	0	624,000
OTTI on investments									(8,771,000)	0	(8,771,000)	0	(8,771,000)
Other Income	(2,858,000)	(791,000)	(3,352,000)	(1,055,000)									(19,000)
Net realized and unrealized gains (losses) on life retrocession embedded derivative	11,599,000	(5,105,000)	13,409,000	2,780,000					(17,546,000)	0	(17,546,000)	0	(17,546,000)
Net income (loss)	(275,579,000)	275,878,000	15,897,000	662,410,000									(6,547,000)
Change in net unrealized gains (losses) on investments, net of tax										0	12,297,000	0	12,297,000
Foreign currency translation adjustments, net of tax	(9,602,000)	(23,718,000)	(13,482,000)	(27,637,000)									(5,750,000)
Other Comprehensive Income (Loss), Net of Tax	$ 260,373,000	$ (694,363,000)	$ 470,377,000	$ (809,261,000)									$ 0