XL (XLGLF) Inactive 10-K25 Feb 152014 FY Annual reportFinancial data

Company Profile

Document_And_Entity_Informatio

Document And Entity Information (USD $)	12 Months Ended
In Billions, except Share data, unless otherwise specified	Dec. 31, 2014	Feb. 19, 2015	Jun. 30, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	XL GROUP PLC
Entity Central Index Key	875159
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		255,239,522
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$8.80

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Investments:
Fixed maturities, at fair value (amortized cost: 2014, $27,728,771; 2013, $27,111,874)	$29,359,034	$27,500,136
Equity securities, at fair value (cost: 2014, $763,833; 2013, $903,201)	868,292	1,040,237
Short-term investments, at fair value (amortized cost: 2014, $257,221; 2013, $455,470)	256,727	456,288
Total investments available for sale	30,484,053	28,996,661
Fixed maturities, trading at fair value (amortized cost: 2014, $1,180; 2013, nil)	1,171	0
Fixed maturities, held to maturity at amortized cost (fair value: 2014, nil; 2013, $3,131,235)	0	2,858,695
Investments in affiliates	1,637,620	1,370,943
Other investments	1,248,439	1,164,630
Total investments	33,371,283	34,390,929
Cash and cash equivalents	2,521,814	1,800,832
Accrued investment income	315,964	346,809
Deferred acquisition costs	354,533	670,659
Ceded unearned premiums	952,525	788,871
Premiums receivable	2,473,736	2,612,602
Reinsurance balances receivable	131,519	118,885
Unpaid losses and loss expenses recoverable	3,429,368	3,435,230
Receivable from investments sold	92,762	144,765
Goodwill and other intangible assets	447,952	411,611
Deferred tax asset	204,491	237,884
Other assets	750,872	693,810
Total assets	45,046,819	45,652,887
Liabilities:
Unpaid losses and loss expenses	19,353,243	20,481,065
Deposit liabilities	1,245,367	1,509,243
Future policy benefit reserves	4,707,199	4,803,816
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable: 2014, $4,265,678; 2013, nil)	1,155,016	0
Unearned premiums	3,973,132	3,846,526
Notes payable and debt	1,662,580	2,263,203
Reinsurance balances payable	493,230	302,399
Payable for investments purchased	42,291	60,162
Deferred tax liability	66,246	86,330
Other liabilities	912,748	950,845
Total liabilities	33,611,052	34,303,589
Commitments and Contingencies
Shareholders' Equity:
Ordinary shares, 999,990,000 authorized, par value $0.01; issued and outstanding (2014, 255,182,955; 2013, 278,253,308)	2,552	2,783
Additional paid in capital	7,359,102	7,994,100
Accumulated other comprehensive income	1,484,458	736,657
Retained earnings	1,187,640	1,264,093
Shareholders' equity attributable to XL Group plc	10,033,752	9,997,633
Non-controlling interest in equity of consolidated subsidiaries	1,402,015	1,351,665
Total shareholders' equity	11,435,767	11,349,298
Total liabilities and shareholders' equity	$45,046,819	$45,652,887

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parentheticals) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Amortized cost of fixed maturities, available for sale	$27,728,771	$27,111,874
Cost of equity securities, available for sale	763,833	903,201
Amortized cost of short-term investments, available for sale	257,221	455,470
Amortized cost of fixed maturities, trading	1,180	0
Fair value of held to maturity securities	$0	$3,131,235
Ordinary shares, shares authorized (in shares)	999,990,000	999,990,000
Ordinary shares, par value (in dollars per share)	$0.01	$0.01
Ordinary shares, shares issued (in shares)	255,182,955	278,253,308
Ordinary shares, shares outstanding (in shares)	255,182,955	278,253,308

CONSOLIDATED_STATEMENTS_OF_INC

CONSOLIDATED STATEMENTS OF INCOME (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Net premiums earned	$5,895,070	$6,309,521	$6,090,437
Net investment income	918,625	957,716	1,012,348
Realized investment gains (losses):
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets	107,462	87,777	14,098
Net realized and unrealized gains (losses) on derivative instruments	29,886	7,798	5,221
Income (loss) from investment fund affiliates	95,816	138,391	58,504
Fee income and other	43,630	40,031	51,789
Total revenues	6,602,267	7,541,234	7,232,397
Expenses:
Net losses and loss expenses incurred	3,258,393	3,731,464	3,765,482
Claims and policy benefits	242,963	465,702	486,195
Acquisition costs	738,118	909,323	913,492
Operating expenses	1,341,315	1,213,178	1,173,955
Foreign exchange (gains) losses	-37,568	-28,243	10,545
Loss on sale of life reinsurance subsidiary	666,423	0	0
Interest expense	134,106	155,462	172,204
Total expenses	6,343,750	6,446,886	6,521,873
Income (loss) before income tax and income (loss) from operating affiliates	258,517	1,094,348	710,524
Income (loss) from operating affiliates	107,218	119,804	53,887
Provision (benefit) for income tax	96,897	77,505	34,028
Net income (loss)	268,838	1,136,647	730,383
Non-controlling interests	80,498	76,731	79,255
Net income (loss) attributable to ordinary shareholders	188,340	1,059,916	651,128
Weighted average ordinary shares and ordinary share equivalents outstanding - basic (in shares)	267,103	287,801	307,372
Weighted average ordinary shares and ordinary share equivalents outstanding - diluted (in shares)	271,527	292,069	310,282
Earnings (loss) per ordinary share and ordinary share equivalent - basic (in dollars per share)	$0.71	$3.68	$2.12
Earnings (loss) per ordinary share and ordinary share equivalent - diluted (in dollars per share)	$0.69	$3.63	$2.10
Exclude Life Funds Withheld Assets [Member]
Revenues:
Net investment income	789,050	957,716	1,012,348
Realized investment gains (losses):
Net realized gains (losses) on investments sold	158,733	104,076	94,807
Other-than-temporary impairments (OTTI) on investments	-33,508	-10,266	-54,301
OTTI on investments transferred to (from) other comprehensive income	-2,234	-6,033	-26,408
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets	122,991	87,777	14,098
Life Funds Withheld Assets [Member]
Revenues:
Net investment income	129,575	0	0
Realized investment gains (losses):
Net realized gains (losses) on investments sold	5,067	0	0
Other-than-temporary impairments (OTTI) on investments	-20,587	0	0
Net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets	-9	0	0
Net realized and unrealized gains (losses) on derivative instruments	($488,222)	$0	$0

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net income (loss) attributable to ordinary shareholders	$188,340	$1,059,916	$651,128
Unrealized gains on held to maturity investment portfolio at time of transfer to available for sale, net of tax	424,861	0	0
Cumulative adjustments recorded to value of future policy benefit reserves, amount	-400,456	-44,660	0
Change in net unrealized gains (losses) on affiliate and other investments, net of tax	35,143	26,637	46,162
Change in OTTI losses recognized in other comprehensive income, net of tax	13,143	32,181	67,280
Change in underfunded pension liability	-7,550	7,653	-3,371
Change in value of cash flow hedge	255	439	439
Foreign currency translation adjustments	-25,729	-54,858	-8,156
Comprehensive income (loss)	936,141	276,553	1,588,083
Exclude Life Funds Withheld Assets [Member]
Change in net unrealized gains (losses) on investments, net of tax	434,051	-750,755	834,601
Life Funds Withheld Assets [Member]
Change in net unrealized gains (losses) on investments, net of tax	$274,083	$0	$0

CONSOLIDATED_STATEMENTS_OF_SHA

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $)	Total	Ordinary Shares	Additional Paid in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Deficit)	Non-controlling Interest in Equity of Consolidated Subsidiaries	Exclude Life Funds Withheld Assets [Member]	Exclude Life Funds Withheld Assets [Member]	Life Funds Withheld Assets [Member]	Life Funds Withheld Assets [Member]
In Thousands	Total	Ordinary Shares	Additional Paid in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Deficit)		Exclude Life Funds Withheld Assets [Member]	Accumulated Other Comprehensive Income (Loss)	Life Funds Withheld Assets [Member]	Accumulated Other Comprehensive Income (Loss)
Balance, beginning of year at Dec. 31, 2011		$3,156	$8,938,679	$583,065	($113,244)	$1,344,472
Issuance of ordinary shares		10	1,387
Buybacks of ordinary shares		-183	-402,748		0
Exercise of stock options		4
Exercise of stock options, net of tax			5,545
Share based compensation expense			41,889
Change in net unrealized gains (losses) on investments, net of tax							834,601	834,601	0	0
Unrealized gains on held to maturity investment portfolio at time of transfer to available for sale, net of tax	0			0
Cumulative adjustments recorded to value of future policy benefit reserves, amount	0			0
Change in net unrealized gains (losses) on affiliate and other investments, net of tax	46,162			46,162
Change in OTTI losses recognized in other comprehensive income, net of tax	67,280			67,280
Change in underfunded pension liability	-3,371			-3,371
Change in value of cash flow hedge	439			439
Foreign currency translation adjustments	-8,156			-8,156
Net income (loss) attributable to ordinary shareholders	651,128				651,128
Dividends on ordinary shares					-135,565
Non-controlling interests - contributions						1,500
Non-controlling interests - distributions						0
Non-controlling interests						113
Non-controlling interest share in change in accumulated other comprehensive income (loss)						240
Non-controlling interests - deconsolidation						0
Balance, end of year at Dec. 31, 2012	11,856,403	2,987	8,584,752	1,520,020	402,319	1,346,325
Issuance of ordinary shares		13	29
Buybacks of ordinary shares		-226	-639,292		-36,098
Exercise of stock options		9
Exercise of stock options, net of tax			12,614
Share based compensation expense			35,997
Change in net unrealized gains (losses) on investments, net of tax							-750,755	-750,755	0	0
Unrealized gains on held to maturity investment portfolio at time of transfer to available for sale, net of tax	0			0
Cumulative adjustments recorded to value of future policy benefit reserves, amount	-44,660			-44,660
Change in net unrealized gains (losses) on affiliate and other investments, net of tax	26,637			26,637
Change in OTTI losses recognized in other comprehensive income, net of tax	32,181			32,181
Change in underfunded pension liability	7,653			7,653
Change in value of cash flow hedge	439			439
Foreign currency translation adjustments	-54,858			-54,858
Net income (loss) attributable to ordinary shareholders	1,059,916				1,059,916
Dividends on ordinary shares					-162,044
Non-controlling interests - contributions						7,747
Non-controlling interests - distributions						-37
Non-controlling interests						-500
Non-controlling interest share in change in accumulated other comprehensive income (loss)						-29
Non-controlling interests - deconsolidation						-1,841
Balance, end of year at Dec. 31, 2013	11,349,298	2,783	7,994,100	736,657	1,264,093	1,351,665
Issuance of ordinary shares		12	27
Buybacks of ordinary shares		-247	-708,993		-92,713
Exercise of stock options		4
Exercise of stock options, net of tax			6,363
Share based compensation expense			67,605
Change in net unrealized gains (losses) on investments, net of tax							434,051	434,051	274,083	274,083
Unrealized gains on held to maturity investment portfolio at time of transfer to available for sale, net of tax	424,861			424,861
Cumulative adjustments recorded to value of future policy benefit reserves, amount	-400,456			-400,456
Change in net unrealized gains (losses) on affiliate and other investments, net of tax	35,143			35,143
Change in OTTI losses recognized in other comprehensive income, net of tax	13,143			13,143
Change in underfunded pension liability	-7,550			-7,550
Change in value of cash flow hedge	255			255
Foreign currency translation adjustments	-25,729			-25,729
Net income (loss) attributable to ordinary shareholders	188,340				188,340
Dividends on ordinary shares					-172,080
Non-controlling interests - contributions						48,261
Non-controlling interests - distributions						-1,666
Non-controlling interests						3,755
Non-controlling interest share in change in accumulated other comprehensive income (loss)						0
Non-controlling interests - deconsolidation						0
Balance, end of year at Dec. 31, 2014	$11,435,767	$2,552	$7,359,102	$1,484,458	$1,187,640	$1,402,015

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows provided by (used in) operating activities:
Net income (loss)	$268,838	$1,136,647	$730,383
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Net realized (gains) losses on investments	-107,462	-87,777	-14,098
Net realized and unrealized (gains) losses on derivative instruments	-29,886	-7,798	-5,221
Amortization of premiums (discounts) on fixed maturities	153,849	166,621	169,353
(Income) loss from investment and operating affiliates	-129,915	-229,386	-112,391
Loss on sale of life reinsurance subsidiary	666,423	0	0
Share based compensation	81,287	46,489	47,472
Depreciation	56,118	56,229	57,280
Accretion of deposit liabilities	11,195	47,256	81,269
Changes in:
Unpaid losses and loss expenses	-427,528	-88,636	-287,972
Future policy benefit reserves	-229,204	-164,923	-187,400
Funds withheld on life retrocession agreements, net	-218,144	0	0
Unearned premiums	253,396	65,279	182,963
Premiums receivable	15,248	-27,334	-127,633
Unpaid losses and loss expenses recoverable	-44,688	-36,897	305,675
Ceded unearned premiums	-191,242	-196,674	14,923
Reinsurance balances receivable	-17,736	-60,317	162,280
Deferred acquisition costs	303,998	8,532	-649
Reinsurance balances payable	160,916	161,132	48,159
Deferred tax asset - net	-33,735	-29,230	-28,556
Derivatives	42,187	-22,324	7,252
Other assets	33,344	-26,945	20,924
Other liabilities	-147,744	60,331	50,342
Other	5,447	9,702	-58,249
Total adjustments	694,346	-356,670	325,723
Net cash provided by (used in) operating activities	963,184	779,977	1,056,106
Cash flows provided by (used in) investing activities:
Proceeds from sale of fixed maturities and short-term investments	4,896,112	4,341,429	3,604,792
Proceeds from redemption of fixed maturities and short-term investments	3,601,793	4,008,333	4,579,651
Proceeds from sale of equity securities	571,410	245,538	221,617
Purchases of fixed maturities and short term investments	-7,158,258	-9,143,973	-8,902,879
Purchases of equity securities	-445,504	-534,356	-362,021
Proceeds from sale of affiliates	240,785	190,954	133,375
Purchases of affiliates	-371,226	-353,678	-138,027
Proceeds from sale of life reinsurance subsidiary	570,000	0	0
Other, net	-193,491	47,891	-79,101
Net cash provided by (used in) investing activities	1,711,621	-1,197,862	-942,593
Cash flows provided by (used in) financing activities:
Proceeds from issuance of ordinary shares and exercise of stock options	6,367	12,623	5,413
Buybacks of ordinary shares	-801,953	-675,617	-402,930
Dividends paid on ordinary shares	-169,620	-160,155	-134,799
Distributions to non-controlling interests	-78,465	-77,670	-78,987
Contributions from non-controlling interest	48,261	7,747	1,500
Proceeds from issuance of debt	0	592,615	0
Repayment of debt	-600,000	0	-600,000
Deposit liabilities	-268,298	-94,386	-134,950
Net cash provided by (used in) financing activities	-1,863,708	-394,843	-1,344,753
Effects of exchange rate changes on foreign currency cash	-90,115	-4,818	24,493
Increase (decrease) in cash and cash equivalents	720,982	-817,546	-1,206,747
Cash and cash equivalents b beginning of period	1,800,832	2,618,378	3,825,125
Cash and cash equivalents b end of period	2,521,814	1,800,832	2,618,378
Supplemental cash flow disclosures:
Net taxes paid	20,168	96,469	34,465
Interest paid on notes payable and debt	121,285	97,125	116,689
Life Funds Withheld Assets [Member]
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Net realized (gains) losses on investments	15,529
Net realized and unrealized (gains) losses on derivative instruments	$488,222	$0	$0

General

General	12 Months Ended
General	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
General	General
	XL Group plc, through its operating subsidiaries (collectively the “Company” or “XL”), is a leading provider of insurance and reinsurance coverages to industrial, commercial and professional firms, insurance companies and other enterprises on a worldwide basis. The Company and its various subsidiaries operate globally in 25 countries, through the Company's two business segments: Insurance and Reinsurance. These segments are further discussed in Note 5, “Segment Information.”
	For periods prior to July 1, 2010, unless the context otherwise indicates, references herein to the “Company” are to, and these financial statements include the accounts of, XLIT Ltd. (formerly, XL Capital Ltd), a Cayman Islands exempted company (“XL-Cayman”), and its consolidated subsidiaries. For periods subsequent to July 1, 2010, unless the context otherwise indicates, references herein to the “Company” are to, and these financial statements include the accounts of, XL Group plc, an Irish public limited company (“XL-Ireland”), and its consolidated subsidiaries.
	On July 1, 2010, XL-Ireland and XL-Cayman completed a redomestication transaction in which all of the ordinary shares of XL-Cayman were exchanged for all of the ordinary shares of XL-Ireland (the “Redomestication”). As a result, XL-Cayman became a wholly owned subsidiary of XL-Ireland. On July 23, 2010, the Irish High Court approved XL-Ireland’s creation of distributable reserves, subject to the completion of certain formalities under Irish Company law. These formalities were completed in early August 2010.

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Significant accounting policies	Significant Accounting Policies
	(a) Basis of Preparation and Consolidation
	These consolidated financial statements include the accounts of the Company and all of its subsidiaries. These consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). To facilitate period-to-period comparisons, certain reclassifications have been made to prior year consolidated financial statement amounts to conform to the current year presentation. There was no effect on net income from this change in presentation.
	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The Company’s most significant areas of estimation include:

	▪	unpaid losses and loss expenses and unpaid losses and loss expenses recoverable;

	▪	future policy benefit reserves;

	▪	valuation and other-than-temporary impairments of investments;

	▪	income taxes;

	▪	reinsurance premium estimates; and

	▪	goodwill carrying value.
	While management believes that the amounts included in the consolidated financial statements reflect the Company’s best estimates and assumptions, actual results could differ from these estimates.
	(b) Fair Value Measurements
	Financial Instruments Subject to Fair Value Measurements
	Accounting guidance over fair value measurements requires that a fair value measurement reflect the assumptions market participants would use in pricing an asset or liability based on the best information available. Assumptions include the risks inherent in a particular valuation technique (such as a pricing model) and/or the risks inherent in the inputs to the model. The fair value of a financial instrument is the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (the “exit price”). Instruments that the Company owns (“long positions”) are marked to bid prices and instruments that the Company has sold but not yet purchased (“short positions”) are marked to offer prices. Fair value measurements are not adjusted for transaction costs.
	Basis of Fair Value Measurement
	Fair value measurements accounting guidance also establishes a fair value hierarchy that prioritizes the inputs to the respective valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). An asset or liability’s classification within the fair value hierarchy is based on the lowest level of significant input to its valuation. The three levels of the fair value hierarchy are described further below:

	▪	Level 1 - Quoted prices in active markets for identical assets or liabilities (unadjusted); no blockage factors.

	▪	Level 2 - Other observable inputs (quoted prices in markets that are not active or inputs that are observable either directly or indirectly)—include quoted prices for similar assets/liabilities (adjusted) other than quoted prices in Level 1; quoted prices in markets that are not active; or other inputs that are observable or can be derived principally from or corroborated by observable market data for substantially the full term of the assets or liabilities.

	▪	Level 3 - Unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets or liabilities. Unobservable inputs reflect the reporting entity’s own assumptions about the assumptions that market participants would use in pricing the asset or liability. Level 3 assets and liabilities include financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation.
	Details on assets and liabilities that have been included under the requirements of authoritative guidance on fair value measurements to illustrate the bases for determining the fair values of these items held by the Company are included in each respective significant accounting policy section of this note.
	Fair values of investments and derivatives are based on published market values if available, estimates of fair values of similar issues, or estimates of fair values provided by independent pricing services and brokers. Fair values of financial instruments for which quoted market prices are not available or for which the company believes current trading conditions represent distressed markets are based on estimates using present value or other valuation techniques. The fair values estimated using such techniques are significantly affected by the assumptions used, including the discount rates and the estimated amounts and timing of future cash flows. In such instances, the derived fair value estimates cannot be substantiated by comparison to independent markets and are not necessarily indicative of the amounts that would be realized in a current market exchange.
	(c) Total Investments
	Investments - Available For Sale
	Investments that are considered available for sale (comprised of fixed maturities, equity securities and short-term investments) are carried at fair value. The fair values for available for sale investments are generally sourced from third parties. The fair values of fixed income securities are based upon quoted market values where available, “evaluated bid” prices provided by third party pricing services (“pricing services”) where quoted market values are not available, or by reference to broker or underwriter bid indications where pricing services do not provide coverage for a particular security. To the extent the Company believes current trading conditions represent distressed transactions, the Company may elect to utilize internally generated models.
	It is common industry practice to utilize pricing services as a source for determining the fair values of investments where the pricing services are able to obtain sufficient market corroborating information to allow them to produce a valuation at a reporting date. In addition, in the majority of cases, although a value may be obtained from a particular pricing service for a security or class of similar securities, these values are corroborated against values provided by other pricing services. The pricing services use market approaches to valuations using primarily Level 2 inputs in the vast majority of valuations, or some form of discounted cash flow analysis, to obtain investment values for a small percentage of fixed income securities for which they provide a price. Standard inputs to the valuations provided by the pricing services listed in approximate order of priority for use when available include: reported trades, benchmark yields, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, and reference data. The pricing services may prioritize inputs differently on any given day for any security, and not all inputs listed are available for use in the evaluation process on any given day for each security evaluation; however, the pricing services also monitor market indicators, customer feedback through a price challenge process and industry and economic events. Information of this nature is a trigger to acquire further corroborating market data. When these inputs are not available, they identify “buckets” of similar securities (allocated by asset class types, sectors, sub-sectors, contractual cash flows/structure, and credit rating characteristics) and apply some form of matrix or other modeled pricing to determine an appropriate security value which represents their best estimate as to what a buyer in the marketplace would pay for a security in a current sale. Prices provided by independent pricing services and independent broker quotes can vary widely even for the same security. The use of different methodologies and assumptions may have a material effect on the estimated fair value amounts. While the Company receives values for the majority of the investment securities it holds from pricing services, it is ultimately management’s responsibility to determine whether the values received and recorded in the financial statements are representative of appropriate fair value measurements.
	Broker/dealer quotations are used to value fixed maturities where prices are unavailable from pricing services due to factors specific to the security such as limited liquidity, lack of current transactions, or trades only taking place in privately negotiated transactions. These are considered Level 3 valuations, as significant inputs utilized by brokers may be difficult to corroborate with observable market data, or sufficient information regarding the specific inputs utilized by the broker was not available to support a Level 2 classification.
	Equity securities include investments in open end mutual funds and shares of publicly traded alternative funds. The fair value of equity securities is based upon quoted market values (Level 1), or monthly net asset value statements provided by the investment managers upon which subscriptions and redemptions can be executed (Level 2).
	Short-term investments include investments due to mature within one year from the date of purchase and are valued using the same external factors and in the same manner as fixed income securities.
	Changes in the value of investments available for sale are reflected as unrealized gains or losses on investments, and are included in “accumulated other comprehensive income (loss)", on a net of tax basis.
	All investment transactions are recorded on a trade date basis. Realized gains and losses on sales of equities and fixed income investments are determined on a first-in, first-out basis.
	Investment income is recognized when earned and includes interest and dividend income together with the amortization of premium and discount on fixed maturities and short-term investments, and is recorded net of related investment expenses. Amortization of discounts on fixed maturities includes amortization to expected recovery values for investments that have previously been recorded as other than temporarily impaired. For mortgage-backed securities, and any other holdings for which there is a prepayment risk, prepayment assumptions are evaluated and revised as necessary. Prepayment fees or call premiums that are only payable to the Company when a security is called prior to its maturity are earned when received and reflected in net investment income.
	Investments - Trading
	Investments for which the company has elected the fair value option are classified as trading. Trading securities are carried at fair value with changes included in "Net realized gains (losses) on investments sold." Interest and dividend income from trading securities are included as a component of "Net investment income - Life Funds Withheld Assets" as all trading securities are held in support of the life retrocession arrangements. See Note 3, "Sale of Life Reinsurance Subsidiary," for information regarding the reinsurance arrangement.
	Investments - Held to Maturity
	Investments classified as held to maturity include securities for which the Company has the ability and intent to hold to maturity and are carried at amortized cost. For details see Note 6, “Investments.”
	Investments Related to Life Retrocession Arrangements written on a Funds Withheld Basis
	Designated investments that support the life retrocession arrangements written on a funds withheld basis ("Life Funds Withheld Assets") entered into in connection with the sale of our life reinsurance subsidiary are classified as either available for sale or trading. Investment results for these assets - including interest income, unrealized gains and losses, and gains and losses from sales - are passed directly to the reinsurer pursuant to a contractual arrangement which is accounted for as a derivative. See Note 3, "Sale of Life Reinsurance Subsidiary," for information regarding the reinsurance arrangement.
	Changes in the fair value of the embedded derivative associated with these life retrocession arrangements are recorded in “Net realized and unrealized gains (losses) on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets” on the consolidated statements of income. The fair value of the embedded derivative is included within “Funds withheld on life retrocession arrangements, net of future policy benefit reserves recoverable” on the consolidated balance sheets.
	Investments In Affiliates
	Investments in which the Company has significant influence over the operating and financial policies of the investee are classified as investments in affiliates on the Company’s balance sheets and are accounted for under the equity method of accounting. Under this method, the Company records its proportionate share of income or loss from such investments in its results for the period as well as its portion of movements in certain of the investee shareholders’ equity balances. When financial statements of the affiliate are not available on a timely basis to record the Company’s share of income or loss for the same reporting periods as the Company, the most recently available financial statements are used. This lag in reporting is applied consistently. Distributions received from affiliates representing returns on invested capital are recorded as operating cash flows, while distributions representing returns of invested capital or proceeds upon sale of all or a portion of an affiliate are recorded as investing cash flows.
	The Company generally records its alternative and private investment fund affiliates on a one-month and three-month lag, respectively, and its operating affiliates on a three-month lag. Significant influence is generally deemed to exist where the Company has an investment of 20% or more in the common stock of a corporation or an investment of 3% or more in closed end funds, limited partnerships, LLCs or similar investment vehicles. Significant influence is considered for other strategic investments on a case-by-case basis. Investments in affiliates are not subject to fair value measurement guidance as they are not considered to be fair value measured investments under GAAP. However, impairments associated with investments in affiliates that are deemed to be other-than-temporary are calculated in accordance with fair value measurement guidance and appropriate disclosures included within the financial statements during the period the losses are recorded.
	Other Investments
	Contained within this asset class are equity interests in investment funds, limited partnerships and unrated tranches of collateralized debt obligations for which the Company does not have sufficient rights or ownership interests to follow the equity method of accounting. The Company accounts for equity securities that do not have readily determinable market values at estimated fair value as it has no significant influence over these entities. Also included within other investments are structured transactions, which are carried at amortized cost.
	Fair values for other investments, principally other direct equity investments, investment funds and limited partnerships, are primarily based on the net asset value provided by the investment manager, the general partner or the respective entity, recent financial information, available market data and, in certain cases, management judgment, if required. These entities generally carry their trading positions and investments, the majority of which have underlying securities valued using Level 1 or Level 2 inputs, at fair value as determined by their respective investment managers; accordingly, these investments are generally classified as Level 2. Private equity investments are classified as Level 3. The net unrealized gain or loss on investments, net of tax, is included in “Accumulated other comprehensive income (loss).” Any unrealized loss in value considered by management to be other-than-temporary is charged to income in the period in which it is determined.
	Overseas deposits include investments in private funds related to Lloyd’s syndicates in which the underlying instruments are primarily fixed maturities. The funds themselves do not trade on an exchange and therefore are not included within available for sale securities. Also included in overseas deposits are restricted balances held by Lloyd’s syndicates for solvency purposes which are primarily invested in cash and cash equivalents. Given the restricted nature of these balances, they are included in other investments on the balance sheets. Each of these investment types is considered a Level 2 valuation.
	The Company historically participated in structured transactions that included cash loans supporting project finance transactions and providing liquidity facility financing to a structured project deal in 2009, and the Company also invested in a payment obligation with an insurance company. These transactions are carried at amortized cost. For further details see Note 4, “Fair Value Measurements,” and Note 8, “Other Investments.”
	(d) Premiums and Acquisition Costs
	Insurance premiums written are recorded in accordance with the terms of the underlying policies. Reinsurance premiums written are recorded at the inception of the policy and are estimated based upon information received from ceding companies and any subsequent differences arising on such estimates are recorded in the period they are determined. For multi-year reinsurance treaties which are payable in annual installments, generally, only the initial annual installment is included as premiums written at policy inception due to the ability of the reinsured to commute or cancel coverage during the term of the policy. The remaining annual installments are included as premiums written at each successive anniversary date within the multi-year term.
	Premiums are earned on a pro-rata basis over the period the coverage is provided. Unearned premiums represent the portion of premiums written applicable to the unexpired terms of policies in force. Net premiums earned are presented after deductions for reinsurance ceded, as applicable.
	Mandatory reinstatement premiums are recognized and earned at the time a loss event occurs.
	Life and annuity premiums from long duration contracts that transfer significant mortality or morbidity risks are recognized as revenue and earned when due from policyholders. Life and annuity premiums from long duration contracts that do not subject the Company to risks arising from policyholder mortality or morbidity are accounted for as investment contracts and presented within deposit liabilities.
	The Company has periodically written retroactive loss portfolio transfer contracts. These contracts are evaluated to determine whether they meet the established criteria for reinsurance accounting, and, if so, at inception, written premiums are fully earned and corresponding losses and loss expense recognized. The contracts can cause significant variances in gross premiums written, net premiums written, net premiums earned, and net incurred losses in the years in which they are written. Reinsurance contracts sold not meeting the established criteria for reinsurance accounting are recorded using the deposit method.
	Acquisition costs, which vary with and are directly related to the acquisition of policies, consist primarily of commissions paid to brokers and cedants, and are deferred and amortized over the period during which the premiums are earned. Acquisition costs are shown net of contractual commissions earned on reinsurance ceded. Future earned premiums, the anticipated losses and other costs (and in the case of a premium deficiency, investment income) related to those premiums, are also considered in determining the level of acquisition costs to be deferred.
	(e) Reinsurance
	In the normal course of business, the Company seeks to reduce the potential amount of loss arising from claims events by reinsuring certain levels of risk assumed in various areas of exposure with other insurers or reinsurers. Reinsurance premiums ceded are expensed (and any commissions recorded thereon are earned) on a monthly pro-rata basis over the period the reinsurance coverage is provided. Ceded unearned reinsurance premiums represent the portion of premiums ceded applicable to the unexpired term of policies in force. Mandatory reinstatement premiums ceded are recorded at the time a loss event occurs. Amounts recoverable from reinsurers are estimated in a manner consistent with the claim liability associated with the reinsured policy. Provisions are made for estimated unrecoverable reinsurance.
The Company enters into reinsurance agreements with other companies in the normal course of business. All premium and loss-related balances related to reinsurance agreements are reported on a gross basis within our consolidated balance sheets, with the exception of the life retrocession arrangements written on a funds withheld basis. The future policy benefit reserves recoverable related to these retrocession arrangements are netted against the funds withheld liability owing to the counterparty on the consolidated balance sheets due to the contractual right of offset.
During the year ended December 31, 2014, the Company recorded $20 million, net of tax, to premiums earned and associated tax accruals, related to reinstatement premiums due under assumed reinsurance contracts arising from unpaid losses and loss expenses reported in a prior period. We evaluated the quantitative and qualitative aspects of this correction and concluded that the impact of recognizing it during the third quarter of 2014 was not material to the consolidated financial statements, nor is it material to previously issued consolidated financial statements in prior periods.
(f) Fee Income and Other
Fee income and other includes fees received for insurance and product structuring services provided and is earned over the service period of the contract. Any adjustments to fees earned or the service period are reflected in income in the period when determined.
(g) Other-Than-Temporary Impairments (“OTTI”) of Available for Sale and Held to Maturity Securities
The Company’s process for identifying declines in the fair value of investments that are other-than-temporary involves consideration of several factors. These primary factors include (i) an analysis of the liquidity, business prospects and financial condition of the issuer including consideration of credit ratings, (ii) the significance of the decline, (iii) an analysis of the collateral structure and other credit support, as applicable, of the securities in question, and (iv) for debt securities, whether the Company intends to sell such securities. In addition, the authoritative guidance requires that OTTI for certain asset backed and mortgage backed securities is recognized if the fair value of the security is less than its discounted cash flow value and there has been a decrease in the present value of the expected cash flows since the last reporting period. Where the Company’s analysis of the above factors results in the Company’s conclusion that declines in fair values are other-than-temporary, the cost of the security is written down to discounted cash flow and a portion of the previously unrealized loss is therefore realized in the period such determination is made.
If the Company intends to sell an impaired debt security, or it is more likely than not that it will be required to sell the security before recovery of its amortized cost basis, the impairment is other-than-temporary and is recognized currently in earnings in an amount equal to the entire difference between fair value and amortized cost.
In instances in which the Company determines that a credit loss exists but the Company does not intend to sell the security, and it is not more likely than not that the Company will be required to sell the security before the anticipated recovery of its remaining amortized cost basis, the OTTI is separated into (1) the amount of the total impairment related to the credit loss and (2) the amount of the total impairment related to all other factors (i.e. the noncredit portion). The amount of the total OTTI related to the credit loss is recognized in earnings and the amount of the total OTTI related to all other factors is recognized in accumulated other comprehensive loss. The total OTTI is presented in the income statement with an offset for the amount of the total OTTI that is recognized in accumulated other comprehensive loss. Absent the intent or requirement to sell a security, if a credit loss does not exist, any impairment is considered to be temporary.
The noncredit portion of any OTTI losses on securities classified as available for sale is recorded as a component of other comprehensive income with an offsetting adjustment to the carrying value of the security. The fair value adjustment could increase or decrease the carrying value of the security. The noncredit portion of any OTTI losses recognized in accumulated other comprehensive loss for debt securities classified as held to maturity would be accreted over the remaining life of the debt security (in a pro rata manner based on the amount of actual cash flows received as a percentage of total estimated cash flows) as an increase in the carrying value of the security until the security is sold, the security matures, or there is an additional OTTI that is recognized in earnings.
In periods subsequent to the recognition of an OTTI loss, the other-than-temporarily impaired debt security is accounted for as if it had been purchased on the measurement date of the OTTI at an amount equal to the previous amortized cost basis less the credit-related OTTI recognized in earnings. For debt securities for which credit-related OTTI is recognized in earnings, the difference between the new cost basis and the cash flows expected to be collected is accreted into interest income over the remaining life of the security in a prospective manner based on the estimated amount and timing of future estimated cash flows.
With respect to securities where the decline in value is determined to be temporary and the security’s amortized cost is not written down, a subsequent decision may be made to sell that security and realize a loss. Subsequent decisions on security sales are made within the context of overall risk monitoring, changing information, market conditions generally and assessing value relative to other comparable securities. Day-to-day management of the Company’s investment portfolio is outsourced to third party investment manager service providers. While these investment manager service providers may, at a given point in time, believe that the preferred course of action is to hold securities with unrealized losses that are considered temporary until such losses are recovered, the dynamic nature of the portfolio management may result in a subsequent decision to sell the security and realize the loss, based upon a change in market and other factors described above. The Company believes that subsequent decisions to sell such securities are consistent with the classification of the Company’s portfolio as available for sale.
There are risks and uncertainties associated with determining whether declines in the fair value of investments are other-than-temporary. These include subsequent significant changes in general economic conditions as well as specific business conditions affecting particular issuers, the Company’s liability profile, subjective assessment of issue-specific factors (seniority of claims, collateral value, etc.), future financial market effects, stability of foreign governments and economies, future rating agency actions and significant disclosure of accounting, fraud or corporate governance issues that may adversely affect certain investments. In addition, significant assumptions and management judgment are involved in determining if the decline is other-than-temporary. If management determines that a decline in fair value is temporary, then a security’s value is not written down at that time. However, there are potential effects upon the Company’s future earnings and financial position should management later conclude that some of the current declines in the fair value of the investments are other-than-temporary declines. For further details on the factors considered in evaluation of OTTI see Note 6, “Investments.”
(h) Derivative Instruments
The Company recognizes all derivatives as either assets or liabilities in the balance sheets and measures those instruments at fair value. Except for the embedded derivative associated with the life retrocession agreement discussed above within (c) "Investments Related to Life Retrocession Arrangements written on a Funds Withheld Basis", the changes in fair value of derivatives are shown in the consolidated statements of income as “net realized and unrealized gains and losses on derivative instruments,” unless the derivatives are designated as hedging instruments. The accounting for derivatives that are designated as hedging instruments is discussed below. Changes in fair value of derivatives may create volatility in the Company’s results of operations from period to period. Amounts recognized for the right to reclaim cash collateral (a receivable) or the obligation to return cash collateral (a payable) are offset against net fair value amounts recognized in the consolidated balance sheets for derivative instruments executed with the same counterparty under the same netting arrangement to the extent that the Company intends to settle the amounts on a net basis.
Derivative contracts can be exchange-traded or over-the-counter (“OTC”). Exchange-traded derivatives (futures and options) typically fall within Level 1 of the fair value hierarchy depending on whether they are deemed to be actively traded or not. OTC derivatives are valued using market transactions and other market evidence whenever possible, including market-based inputs to models, model calibration to market clearing transactions, broker or dealer quotations or alternative pricing sources where an understanding of the inputs utilized in arriving at the valuations is obtained. Where models are used, the selection of a particular model to value an OTC derivative depends upon the contractual terms and specific risks inherent in the instrument as well as the availability of pricing information in the market. The Company generally uses similar models to value similar instruments. Valuation models require a variety of inputs, including contractual terms, market prices, yield curves, credit curves, measures of volatility, prepayment rates and correlations of such inputs. For OTC derivatives that trade in liquid markets, such as generic forwards, interest rate swaps and options, model inputs can generally be verified and model selection does not involve significant management judgment. Such instruments comprise the majority of derivatives held by the Company and are typically classified within Level 2 of the fair value hierarchy.
Certain OTC derivatives trade in less liquid markets with limited pricing information, or required model inputs which are not directly market corroborated, which causes the determination of fair value for these derivatives to be inherently more subjective. Accordingly, such derivatives are classified within Level 3 of the fair value hierarchy. The valuations of less standard or liquid OTC derivatives are typically based on Level 1 and/or Level 2 inputs that can be observed in the market, as well as unobservable Level 3 inputs. Level 1 and Level 2 inputs are regularly updated to reflect observable market changes. Level 3 inputs are only changed when corroborated by evidence such as similar market transactions, pricing services and/or broker or dealer quotations. The Company conducts its non-hedging derivatives activities in three main areas: investment related derivatives, credit derivatives and other non-investment related derivatives.
The Company uses derivative instruments, primarily interest rate swaps, to manage the interest rate exposure associated with certain assets and liabilities. These derivatives are recorded at fair value. On the date the derivative contract is entered into, the Company may designate the derivative as: a hedge of the fair value of a recognized asset or liability (“fair value” hedge); a hedge of the variability in cash flows of a forecasted transaction or of amounts to be received or paid related to a recognized asset or liability (“cash flow” hedge); or a hedge of a net investment in a foreign operation; or the Company may not designate any hedging relationship for a derivative contract.
Fair Value Hedges
Changes in the fair value of a derivative that is designated and qualifies as a fair value hedge, along with the changes in the fair value of the hedged asset or liability that is attributable to the hedged risk, are recorded in current period earnings (through “net realized and unrealized gains and losses on derivative instruments”) with any differences between the net change in fair value of the derivative and the hedged item representing the hedge ineffectiveness. Periodic derivative net coupon settlements are recorded in net investment income with the exception of hedges of Company issued debt, which are recorded in interest expense. The Company may designate fair value hedging relationships where interest rate swaps are used to hedge the changes in fair value of certain fixed rate liabilities and fixed maturity securities due to changes in the designated benchmark interest rate.
Cash Flow Hedges
Changes in the fair value of a derivative that is designated and qualifies as a cash flow hedge are recorded in accumulated other comprehensive income (“AOCI”) and are reclassified into earnings when the variability of the cash flow of the hedged item impacts earnings. Gains and losses on derivative contracts that are reclassified from AOCI to current period earnings are included in the line item in the consolidated statements of operations in which the cash flows of the hedged item are recorded. Any hedge ineffectiveness is recorded immediately in current period earnings as “net realized and unrealized gains and losses on derivative instruments.” Periodic derivative net coupon settlements are recorded in net investment income. The Company may designate cash flow hedging relationships where interest rate swaps are used to mitigate interest rate risk associated with anticipated issuances of debt or other forecasted transactions.
Hedges of the Net Investment in a Foreign Operation
Changes in fair value of a derivative used as a hedge of a net investment in a foreign operation, to the extent effective as a hedge, are recorded in the foreign currency translation adjustments account within AOCI. Cumulative changes in fair value recorded in AOCI are reclassified into earnings upon the sale or complete or substantially complete liquidation of the foreign entity. Any hedge ineffectiveness is recorded immediately in current period earnings as “net realized and unrealized gains and losses on derivative instruments.”
Hedge Documentation and Effectiveness Testing
To qualify for hedge accounting treatment, a derivative must be highly effective in mitigating the designated changes in value or cash flow of the hedged item. At hedge inception, the Company formally documents all relationships between hedging instruments and hedged items, as well as its risk-management objective and strategy for undertaking each hedge transaction. The documentation process includes linking derivatives that are designated as fair value, cash flow, or net investment hedges to specific assets or liabilities on the balance sheets or to specific forecasted transactions. The Company also formally assesses, both at the hedge’s inception and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in fair values or cash flows of hedged items. In addition, certain hedging relationships are considered highly effective if the changes in the fair value or discounted cash flows of the hedging instrument are within a ratio of 80-125% of the inverse changes in the fair value or discounted cash flows of the hedged item. Hedge ineffectiveness is measured using qualitative and quantitative methods. Qualitative methods may include comparison of critical terms of the derivative to the hedged item. Depending on the hedging strategy, quantitative methods may include the “Change in Variable Cash Flows Method,” the “Change in Fair Value Method,” the “Hypothetical Derivative Method” or the “Dollar Offset Method.”
Discontinuance of Hedge Accounting
The Company discontinues hedge accounting prospectively when it determines that the derivative is no longer highly effective in offsetting changes in the fair value or cash flows of a hedged item; the derivative is dedesignated as a hedging instrument; or the derivative expires or is sold, terminated or exercised. When hedge accounting is discontinued because it is determined that the derivative no longer qualifies as an effective fair-value hedge, the derivative continues to be carried at fair value on the balance sheets with changes in its fair value recognized in current period earnings through “net realized and unrealized gains and losses on derivative instruments.” When hedge accounting is discontinued because the Company becomes aware that it is not probable that the forecasted transaction will occur, the derivative continues to be carried on the balance sheets at its fair value, and gains and losses that were accumulated in AOCI are recognized immediately in earnings.
(i) Cash Equivalents
Cash equivalents include fixed interest deposits placed with a maturity of under 90 days when purchased. Bank deposits are not considered to be fair value measurements and as such are not subject to the authoritative guidance on fair value measurement disclosures. Money market funds are classified as Level 1 as these instruments are considered actively traded; however, certificates of deposit are classified as Level 2.
(j) Foreign Currency Translation
Assets and liabilities of foreign operations whose functional currency is not the U.S. dollar are translated at prevailing year end exchange rates. Revenue and expenses of such foreign operations are translated at average exchange rates during the year. The net effect of the translation adjustments for foreign operations, net of applicable deferred income taxes, as well as any gains or losses on intercompany balances for which settlement is not planned or anticipated in the foreseeable future, are included in “accumulated other comprehensive income (loss).”
Monetary assets and liabilities denominated in currencies other than the functional currency of the applicable entity are revalued at the exchange rate in effect at the balance sheet date and revenues and expenses are translated at the exchange rate on the date the transaction occurs with the resulting foreign exchange gains and losses on settlement or revaluation recognized in income.
(k) Goodwill, Intangibles and Other Long-Lived Assets
The Company has recorded goodwill in connection with various acquisitions in prior years. Goodwill represents the excess of the purchase price over the fair value of net assets acquired. In accordance with GAAP authoritative guidance for goodwill and other intangible assets, the Company tests goodwill for potential impairment annually as of June 30, and between annual tests if an event occurs or circumstances change that may indicate that potential exists for the fair value of a reporting unit to be reduced to a level below its carrying amount. For further details on the factors considered in the goodwill impairment evaluation see Note 9, “Goodwill and Other Intangible Assets.”
The Company’s indefinite lived intangible assets consist primarily of acquired insurance and reinsurance licenses. These assets are deemed to have indefinite useful lives and are therefore not subject to amortization. In accordance with GAAP authoritative guidance for goodwill and other intangible assets, the Company tests non-amortized intangible assets for potential impairment annually, or more frequently if events or changes in circumstances indicate that the asset might be impaired. Pursuant to the authoritative guidance, if the carrying value of a non-amortized intangible asset is in excess of its fair value, the asset must be written down to its fair value through the recognition of an impairment charge to earnings.
All of the Company’s depreciable or amortizable long-lived assets such as premises, equipment, agency relationships, and acquired or internally-developed software, are carried at net book value, and are depreciated or amortized on a straight-line basis over their estimated useful lives. The amortization periods approximate the period over which the Company expects to generate future net cash inflows from the use of these assets. All of these assets are subject to impairment testing in accordance with authoritative guidance for the impairment or disposal of long-lived assets when events or conditions indicate that the carrying value of an asset may not be fully recoverable from future cash flows.
(l) Variable Interest Entities ("VIEs")
Investments or other interests that absorb portions of an entity’s expected losses or receive portions of the entity’s expected residual returns are called variable interests. Entities in which the equity investors, as a group, do not have the characteristic of a controlling financial interest, or that do not have sufficient equity at risk to allow them to finance their own activities without additional financial support are referred to as VIEs.
A VIE must be consolidated by its primary beneficiary, which is the variable interest holder that is determined to have the controlling financial interest in the entity. Based upon the nature of the VIE, this is either the entity that has both: a) the power to direct the VIE’s activities that most significantly impact its economic performance, and b) the obligation to absorb losses or receive benefits of the VIE that could potentially be significant to it; or it is the reporting entity that will absorb a majority of the VIE's expected losses, receive a majority of the VIE's expected residual returns, or both. Refer to Note 18, "Variable Interest Entities," for further discussion of the Company’s interests in VIEs.
(m) Non-controlling Interests
Non-controlling shareholders' interests are presented separately in the Company's Consolidated Balance Sheets and Consolidated Statements of Shareholders' Equity as required under GAAP. The net loss (income) attributable to non-controlling interests is presented separately in the Company's Consolidated Statements of Comprehensive Income. Refer to Note 18, “Variable Interest Entities,” and Note 20, “Share Capital,” for further discussion of non-controlling interests in the Company.
(n) Losses and Loss Expenses
Unpaid losses and loss expenses include reserves for reported unpaid losses and loss expenses and for losses incurred but not reported. The reserve for reported unpaid losses and loss expenses for the Company’s property and casualty operations is established by management based on claims reported from insureds or amounts reported from ceding companies, and represent the estimated ultimate cost of events or conditions that have been reported to or specifically identified by the Company.
The reserve for losses incurred but not reported is estimated by management based on loss development patterns determined by reference to the Company’s underwriting practices, the policy form, type of program and historical experience. The Company’s actuaries employ a variety of generally accepted methodologies to determine estimated ultimate loss reserves, including the “Bornhuetter-Ferguson incurred loss method” and frequency and severity approaches.
Certain workers’ compensation and certain U.K. bodily injury liabilities are considered fixed and determinable and are discounted.
Management believes that the reserves for unpaid losses and loss expenses are sufficient to cover losses that fall within coverages assumed by the Company. However, there can be no assurance that losses will not exceed the Company’s total reserves. The methodology of estimating loss reserves is periodically reviewed to ensure that the assumptions made continue to be appropriate and any adjustments resulting from such reviews are reflected in income in the year in which the adjustments are made.
(o) Deposit Liabilities
Contracts entered into by the Company that are not deemed to transfer significant underwriting and/or timing risk are accounted for as deposits, whereby liabilities are initially recorded at an amount equal to the assets received. The Company uses a portfolio rate of return of equivalent duration to the liabilities in determining risk transfer. An initial accretion rate is established based on actuarial estimates whereby the deposit liability is increased to the estimated amount payable over the term of the contract.
The deposit accretion rate is the rate of return required to fund expected future payment obligations (this is equivalent to the “best estimate” of future cash flows), which are determined actuarially based upon the nature of the underlying indemnifiable losses. Accretion of the liability is recorded as interest expense.
The Company periodically reassesses the estimated ultimate liability. Any changes to this liability are reflected as adjustments to interest expense to reflect the cumulative effect of the period the contract has been in force, and by an adjustment to the future accretion rate of the liability over the remaining estimated contract term.
(p) Future Policy Benefit Reserves
The Company estimates the present value of future policy benefits related to long duration contracts using assumptions for investment yields, mortality, and expenses, including a provision for adverse deviation.
The assumptions used to determine future policy benefit reserves are best estimate assumptions that are determined at the inception of the contracts and are locked-in throughout the life of the contract unless a premium deficiency develops. As the experience on the contracts emerges, the assumptions are reviewed. If such review would produce reserves in excess of those currently held, then the locked-in assumptions will be revised and a claim and policy benefit is recognized at that time. The Company includes the cost of reinsurance in its premium deficiency considerations.
Certain life insurance and annuity contracts provide the holder with a guarantee that the benefit received upon death will be no less than a minimum prescribed amount. The contracts are accounted for in accordance with the authoritative guidance on Accounting and Reporting by Insurance Enterprises for Certain Long- Duration Contracts and for Separate Accounts, which requires that the best estimate of future experience be combined with actual experience to determine the benefit ratio used to calculate the policy benefit reserve.
(q) Income Taxes
The Company utilizes the asset and liability method of accounting for income taxes. Under this method, deferred income taxes reflect the net tax effect of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The realizability of deferred tax assets is evaluated based upon management's assessment of taxable income in prior eligible carryback years, future reversals of existing taxable temporary differences, future taxable income exclusive of reversing temporary differences and carryforwards, and tax planning strategies that would, if necessary, be implemented. A valuation allowance may have to be established for any portion of a deferred tax asset that management believes will not be realized.
The Company recognizes the tax benefit from an uncertain tax position taken only if it is more likely than not that the tax position will be sustained upon examination by the relevant tax authority, based on our interpretation of and judgment of the relevant tax law. The Company reviews its uncertain tax positions on a quarterly basis. Tax positions that meet the more likely than not threshold are measured using a probability weighted approach, whereby the largest amount of tax benefit that has a greater than 50% likelihood of being realized upon settlement is recognized. The Company recognizes interest and penalties on underpaid tax as a component of income tax expense.
For the Company’s branch operations investment income is allocated and taxable in certain jurisdictions. The method of allocating this income may be different for tax reporting as compared to GAAP. The Company records the tax effects of this allocation entirely through operations.
(r) Stock Plans
At December 31, 2014, the Company had several stock-based performance incentive programs, which are described more fully in Note 20, “Share Capital.” Stock-based compensation issued under these plans generally has a life of not longer than ten years and vests as set forth at the time of grant. Awards currently vest annually over three or four years from the date of grant. The Company recognizes compensation costs for stock-based awards on a straight-line basis over the requisite service period (usually the vesting period) for each award.
Share-based payments to employees, including grants of employee stock options, are recognized in the financial statements over the vesting period based on their grant date fair values.
Authoritative guidance requires that compensation costs be recognized for unvested stock-based compensation awards over the period through the date that the employee is no longer required to provide future services to earn the award, rather than over the explicit service period. Accordingly, the Company follows a policy of recognizing compensation cost to coincide with the date that the employee is eligible to retire, rather than the actual retirement date, for all stock-based compensation granted.
(s) Per Share Data
Basic earnings per ordinary share is based on weighted average ordinary shares outstanding and excludes any dilutive effects of options and convertible securities. Diluted earnings per ordinary share assumes the exercise of all dilutive stock options and conversion of convertible securities where the contingency for conversion has occurred or been satisfied.
(t) Recent Accounting Pronouncements
In May 2011, the FASB issued an accounting standards update to amend existing requirements for fair value measurements and disclosures. The guidance expands the disclosure requirements around fair value measurements categorized in Level 3 of the fair value hierarchy, requiring quantitative and qualitative information to be disclosed related to: (1) the valuation processes used, (2) the sensitivity of the fair value measurement to changes in unobservable inputs and the interrelationships between those unobservable inputs, and (3) use of a nonfinancial asset in a way that differs from the asset’s highest and best use. The guidance requires disclosure of the level in the fair value hierarchy of items that are not measured at fair value, but whose fair value must be disclosed. It also clarifies and expands upon existing requirements for fair value measurements of financial assets and liabilities, as well as instruments classified in shareholders’ equity. The Company adopted this guidance from January 1, 2012; however, it impacted disclosure only and did not have an impact on the Company’s financial condition, results of operations or cash flows. See Note 4, “Fair Value Measurements,” for these updated disclosures.
In June 2011, the FASB issued an accounting standards update concerning the presentation of comprehensive income in financial statements. This guidance allows an entity the option to present the total of comprehensive income, the components of net income, and the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements. Under both options, an entity is required to present each component of net income along with total net income, each component of other comprehensive income along with a total for other comprehensive income, and a total amount for comprehensive income. This guidance eliminates the option to present the components of other comprehensive income only as part of the statement of changes in shareholders' equity. The guidance does not change the items that must be reported in other comprehensive income or when an item of other comprehensive income must be reclassified to net income. The Company adopted this guidance from January 1, 2012; however, it did not have an impact on the Company's disclosure, financial condition, results of operations or cash flows. In February 2013, the FASB issued an additional accounting standards update related to this topic that requires an entity to provide information about the amounts reclassified out of accumulated other comprehensive income by component. The Company adopted this additional guidance prospectively from January 1, 2013. As this guidance is disclosure-related only and does not change the current requirements for reporting net income or other comprehensive income in financial statements, its adoption did not impact the Company's financial condition, results of operations or cash flows.
In September 2011, the FASB issued an accounting standards update to simplify how entities test goodwill for impairment, by allowing an entity the option to first assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting entity is less than its carrying amount, as a basis for determining whether it is necessary to perform the two-step goodwill impairment test required under GAAP accounting rules. After assessing the circumstances that should be considered in making the qualitative assessment, if an entity determines that the fair value of a reporting unit as compared to its carrying value meets the threshold, then performing the two-step impairment step is unnecessary. In other circumstances, performance of the two-step test is required. The guidance also eliminates the option for an entity to carry forward its detailed calculation of a reporting unit’s fair value in certain situations. The Company adopted this guidance from January 1, 2012. It did not have an impact on the Company’s financial condition, results of operations, or cash flows.
In December 2011, the FASB issued an accounting standards update requiring additional disclosures about financial instruments and derivatives that are either: (1) offset for balance sheet presentation purposes or (2) subject to an enforceable master netting arrangement or similar arrangement, regardless of whether they are offset for balance sheet presentation purposes. In January 2013, the FASB issued an additional accounting standards update related to this topic clarifying that the disclosures would apply only to derivatives, repurchase and reverse repurchase agreements, and securities borrowing and securities lending transactions, each to the extent that they met one of the two conditions provided in the initial accounting standards update. This guidance was adopted from January 1, 2013, on a retrospective basis for all fiscal periods presented. As this guidance is disclosure-related only and does not amend existing balance sheet offsetting guidance, its adoption did not impact the Company's financial condition, results of operations or cash flows.
In July 2012, the FASB issued an accounting standards update to simplify how entities test indefinite-lived intangible assets for impairment. Under this new guidance, an entity is allowed the option to first assess qualitative factors to determine whether it is more likely than not that the fair value of an indefinite-lived intangible asset is less than its carrying value. After assessing the circumstances that should be considered in making the qualitative assessment, if an entity determines that the fair value of the intangible asset as compared to its carrying value meets the threshold, it may bypass the existing requirements to perform a full quantitative impairment test on the intangible asset, a test which otherwise would have to be performed annually, at a minimum. The guidance was effective during the fourth quarter of 2012. The Company adopted this guidance from January 1, 2013. It did not have an impact on the Company’s financial condition, results of operations or cash flows.
In July 2013, the FASB issued an accounting standards update concerning the presentation of unrecognized tax benefits. The objective of the guidance is to improve the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The guidance seeks to reduce the diversity in practice by providing guidance on the presentation of unrecognized tax benefits to better reflect the manner in which an entity would settle, at the reporting date, any additional income taxes that would result from the disallowance of a tax position when net operating loss carryforwards, similar tax losses, or tax credit carryforwards exist. The guidance is effective for annual and interim reporting periods beginning after December 15, 2013, with both early adoption and retrospective application permitted. The Company adopted this guidance from January 1, 2014. It did not have an impact on the Company’s financial condition, results of operations or cash flows.
In April 2014, the FASB issued an accounting standards update intended to improve financial reporting by changing key criteria used to evaluate whether disposal transactions meet the definition of discontinued operations. Under the guidance only those disposals of components of an entity - either by sale or otherwise - which represent strategic shifts that have, or will have, a major effect on an entity’s operations and financial results would qualify for reporting as discontinued operations. Disposals that are considered to be routine in nature can no longer be reported as discontinued operations. However, a disposal may now qualify for discontinued operations reporting even if the disposed component's operations and cash flows are not eliminated from on-going operations of the disposing entity, or if post-disposal, the disposing entity still has significant continuing involvement in the component’s operations. The standard also establishes both additional disclosure requirements and expanded disclosures regarding on-going involvement an entity may have with a discontinued operation after its disposal. The guidance is effective prospectively for all public company disposals (or component reclassifications to held-for-sale) that occur within annual periods beginning on or after December 15, 2014. Early adoption is permitted, but only for disposals (or component reclassifications to held-for-sale) that have not been reported in financial statements issued or available for issuance prior to the effective date. This guidance is not expected to have a significant impact on the Company's financial condition, results of operations or cash flows.
In August 2014, the FASB issued an accounting standards update concerning the evaluation of an entity's ability to continue as a going concern. Under this new guidance, in connection with preparing financial statements for each annual and interim reporting period, an entity's management should evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity's ability to continue as a going concern within one year after the date that the financial statements are issued. Management's evaluation should be based on relevant conditions and events that are known and reasonably knowable at the date that the financial statements are issued. Substantial doubt exists when it is probable that the entity will be unable to meet its obligations as they become due. When management identifies conditions or events that raise substantial doubt about an entity's ability to continue as a going concern, management should consider whether its plans that are intended to mitigate those conditions or events will alleviate the substantial doubt. The mitigating effect of management's plans should be considered only to the extent that it is probable that the plans will be implemented, and if implemented, it is probable that the plans will be effective. If conditions or events raise substantial doubt, the entity should disclose the conditions or events, management's evaluation of their significance in relation to the ability to meet its obligations, and management's plans to mitigate the conditions or events along with whether substantial doubt has been alleviated. The guidance is effective for annual periods ending after December 15, 2016, and interim and annual periods thereafter. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on its financial condition, results of operations or cash flows.
In November 2014, the FASB issued an accounting standards update which provides an acquired entity with the option to reflect assets and liabilities using its acquirer's accounting and reporting basis ("pushdown accounting") within its own separate financial statements. Under this new guidance, an acquired entity may elect the option to apply pushdown accounting in the reporting period in which the change-in control event occurs (on a case by case basis if multiple). If the entity elects to apply pushdown accounting, it should disclose information that enables users of the financial statements to evaluate the effect of pushdown accounting. If pushdown accounting is not applied in the initial reporting period, an acquired entity will have the option to elect to apply it in a subsequent reporting period, however, such an election should be considered a change in accounting principle. Once pushdown accounting is elected, that election is irrevocable. The guidance was effective upon issuance. Its adoption did not have an impact on the financial condition, results of operations or cash flows of the Company or its subsidiaries for the year ended December 31, 2014.

Sale_of_Life_Reinsurance_Subsi

Sale of Life Reinsurance Subsidiary	12 Months Ended
	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Sale of Life Reinsurance Subsidiary	Sale of Life Reinsurance Subsidiary
	On May 1, 2014, a wholly owned subsidiary of the Company, XL Insurance (Bermuda) Ltd (“XLIB”), entered into a sale and purchase agreement with GreyCastle Holdings Ltd. (“GreyCastle”) providing for the sale of 100% of the common shares of XLIB's wholly-owned subsidiary, XL Life Reinsurance (SAC) Ltd ("XLLR"), (subsequent to the transaction, XLLR changed its name to GreyCastle Life Reinsurance (SAC) Ltd ("GCLR")), to GreyCastle for $570 million in cash. This transaction closed on May 30, 2014. As a result of the transaction, the Company ceded the majority of its life reinsurance business to GCLR via 100% quota share reinsurance (the "Life Retro Arrangements"). This transaction covers a substantial portion of our life reinsurance reserves. The Company ceased writing new life reinsurance contracts in 2009 and since that time has been managing the run-off of its life reinsurance operations ("Run-Off Life Operations").
	The Run-Off Life Operations business, including the business subject to the transaction, was previously reported within the Company’s Life operations segment. Subsequent to the transaction, the Company no longer considers the Life operations to be a separate operating segment, and the results of the Run-Off Life Operations are reported within “Corporate and Other.” See Note 5, "Segment Information" for further information. In addition, certain securities within fixed maturities were reclassified from held to maturity to available for sale in conjunction with this transaction. See Note 6, "Investments," for further information.
	All of the reclassified securities are included within Life Funds Withheld Assets, along with certain other available for sale securities as defined in the sale and purchase agreement. The Life Funds Withheld Assets are managed pursuant to agreed investment guidelines that meet the contractual commitments of the XL ceding companies and applicable laws and regulations. All of the investment results associated with the Life Funds Withheld Assets ultimately accrue to GCLR. Because the Company no longer shares in the risks and rewards of the underlying performance of the supporting invested assets, disclosures within the financial statement notes included herein separate the Life Funds Withheld Assets from the rest of the Company's investments.
	At May 30, 2014, gross future policy benefit reserves relating to the Life operations were approximately $5.2 billion. Subsequent to the completion of this transaction the Company retained approximately $0.4 billion of these reserves, and recorded a reinsurance recoverable from GCLR of $4.8 billion. Under the terms of the transaction, the Company continues to own, on a funds withheld basis, assets supporting the Life Retro Arrangements consisting of cash, fixed maturity securities and accrued interest. Based upon the right of offset, the funds withheld liability owing to GCLR is recorded net of future policy benefit reserves recoverable, and is included within “Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable)" on the consolidated balance sheets. The transaction resulted in an overall after-tax U.S. GAAP net loss of $621.3 million.
	At December 31, 2014, gross future policy benefit reserves relating to the Run-Off Life Operations were approximately $4.7 billion, of which the Company retained approximately $0.4 billion, after consideration of its future policy benefit reserves recoverable from GCLR of $4.3 billion. The net funds withheld liability included within “Funds withheld on life retrocession arrangements, net of future policy benefit reserves recoverable" was $1.2 billion. The Company continued to own $5.4 billion of assets supporting the Life Retro Arrangements. See Note 14, “Funds Withheld on Life Retrocession Arrangements,” for further information about the net funds withheld liability.
	The impact of the Life Retro Arrangements on the Company's results from the completion of the transaction on May 30, 2014 through December 31, 2014 was as follows:


	Impact of Life Retro Arrangements	May 30 to December 31,
	(U.S. dollars in thousands)	2014
	Underwriting profit (loss) (1)	$	11,649

	Net investment income - Life Funds Withheld Assets	129,575

	Net realized gains (losses) on investments sold - Life Funds Withheld Assets	5,067

	Net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets	(9		)
	OTTI on investments - Life Funds Withheld Assets	(20,587		)
	Exchange (gains) losses	10,099

	Other income and expenses	(1,610		)
	Net realized and unrealized gains (losses) on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets	(488,222		)
	Net income (loss)	$	(354,038	)
	Change in net unrealized gains (losses) on investments - Life Funds Withheld Assets, net of tax	274,083

	Change in adjustments related to future policy benefit reserves, net of tax	74,009

	Change in cumulative translation adjustment - Life Funds Withheld Assets, net of tax	17,595

	Total changes to other comprehensive income as a result of Life Retro Arrangements	$	365,687

	Comprehensive income (loss) (1)	$	11,649

	____________

	-1	The underwriting profit of $11.6 million relates to a premium adjustment relating to the Life Retro Arrangements transaction which was completed on May 30, 2014. Excluding this transaction, the impact to comprehensive income relating to the Life Retro Arrangements was nil for the year ended December 31, 2014.
	As shown in the table above, although the Company's net income (loss) is subject to variability related to the Life Retro Arrangements, there is no recurring net impact on the Company's future comprehensive income in any period. The life retrocession embedded derivative value includes the interest income, unrealized gains and losses, and realized gains and losses from sales on the Life Funds Withheld Assets subsequent to May 30, 2014.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair value disclosures	Fair Value Measurements
	(a) Fair Value Summary
	The following tables set forth the Company’s assets and liabilities that were accounted for at fair value at December 31, 2014 and 2013 by level within the fair value hierarchy. For further information, see Note 2 (b), “Significant Accounting Policies – Fair Value Measurements”:


	31-Dec-14	Quoted Prices			Significant Other			Significant Other			Collateral and			Balance at
	(U.S. dollars in thousands)	in Active Markets for			Observable			Unobservable			Counterparty			December 31,
		Identical Assets			Inputs			Inputs			Netting			2014
		(Level 1)			(Level 2)			(Level 3)
	Assets
	Fixed maturities - Available for Sale ("AFS") - Excluding Life Funds Withheld Assets
	U.S. Government and Government - Related/Supported	$	—		$	2,171,953		$	—		$	—		$	2,171,953

	Corporate (1)	—			8,772,479			5,894			—			8,778,373

	Residential mortgage-backed securities – Agency (“RMBS - Agency”)	—			3,726,666			1,910			—			3,728,576

	Residential mortgage-backed securities – Non-Agency (“RMBS - Non-Agency”)	—			427,351			—			—			427,351

	Commercial mortgage-backed securities (“CMBS”)	—			1,052,544			—			—			1,052,544

	Collateralized debt obligations (“CDO”)	—			4,076			687,958			—			692,034

	Other asset-backed securities (1)	—			1,060,005			5,288			—			1,065,293

	U.S. States and political subdivisions of the States	—			2,021,272			—			—			2,021,272

	Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	—			4,240,073			—			—			4,240,073

	Total fixed maturities - AFS - Excluding Life Funds Withheld Assets, at fair value	$	—		$	23,476,419		$	701,050		$	—		$	24,177,469

	Equity securities, at fair value	502,284			366,008			—			—			868,292

	Short-term investments, at fair value (1)(2)	—			256,727			—			—			256,727

	Total investments AFS - Excluding Life Funds Withheld Assets	$	502,284		$	24,099,154		$	701,050		$	—		$	25,302,488

	Fixed maturities - AFS - Life Funds Withheld Assets
	U.S. Government and Government - Related/Supported	—			18,724			—			—			18,724

	Corporate (1)	—			2,817,980			—			—			2,817,980

	RMBS - Agency	—			3,782			—			—			3,782

	RMBS - Non-Agency	—			85,335			—			—			85,335

	CMBS	—			193,167			—			—			193,167

	Other asset-backed securities	—			273,541			—			—			273,541

	Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	—			1,789,036			—			—			1,789,036

	Total fixed maturities - AFS - Life Funds Withheld Assets, at fair value	—			5,181,565			—			—			5,181,565

	Total investments - AFS, at fair value	502,284			29,280,719			701,050			—			30,484,053

	Fixed maturities - Trading
	Corporate (1)	—			1,171			—			—			1,171

	Total fixed maturities - Trading, at fair value	—			1,171			—			—			1,171

	Cash equivalents (3)	1,103,877			397,955			—			—			1,501,832

	Cash equivalents - Life Funds Withheld Assets	460			132,738			—			—			133,198

Other investments (4)	—			708,974			185,083			—			894,057

Other assets (5)	—			122,996			13,663			(696		)	135,963

Total assets accounted for at fair value	$	1,606,621		$	30,644,553		$	899,796		$	(696	)	$	33,150,274

Liabilities
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable) (6)	$	—		$	450,831		$	—		$	—		$	450,831

Financial instruments sold, but not yet purchased (7)	4,737			25,669			—			—			30,406

Other liabilities (5)	—			7,757			23,427			(696		)	30,488

Total liabilities accounted for at fair value	$	4,737		$	484,257		$	23,427		$	(696	)	$	511,725



31-Dec-13	Quoted Prices			Significant Other			Significant Other			Collateral and			Balance at
(U.S. dollars in thousands)	in Active Markets for			Observable			Unobservable			Counterparty			December 31,
	Identical Assets			Inputs			Inputs			Netting			2013
	(Level 1)			(Level 2)			(Level 3)
Assets
U.S. Government and Government - Related/Supported	$	—		$	2,501,851		$	—		$	—		$	2,501,851

Corporate (1)	—			11,094,257			31,573			—			11,125,830

RMBS – Agency	—			3,535,649			10,473			—			3,546,122

RMBS – Non-Agency	—			398,759			9			—			398,768

CMBS	—			1,234,262			12,533			—			1,246,795

CDO	—			7,060			710,253			—			717,313

Other asset-backed securities (1)	—			1,230,227			11,877			—			1,242,104

U.S. States and political subdivisions of the States	—			1,845,812			—			—			1,845,812

Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	—			4,875,541			—			—			4,875,541

Total fixed maturities, at fair value	$	—		$	26,723,418		$	776,718		$	—		$	27,500,136

Equity securities, at fair value	540,331			499,906			—			—			1,040,237

Short-term investments, at fair value (1)(2)	—			454,273			2,015			—			456,288

Total investments available for sale	$	540,331		$	27,677,597		$	778,733		$	—		$	28,996,661

Cash equivalents (3)	834,514			226,636			—			—			1,061,150

Other investments (4)	—			757,110			113,472			—			870,582

Other assets (5)	—			27,487			—			(1,342		)	26,145

Total assets accounted for at fair value	$	1,374,845		$	28,688,830		$	892,205		$	(1,342	)	$	30,954,538

Liabilities
Financial instruments sold, but not yet purchased (7)	$	—		$	28,861		$	—		$	—		$	28,861

Other liabilities (5)	—			76,375			29,110			(1,342		)	104,143

Total liabilities accounted for at fair value	$	—		$	105,236		$	29,110		$	(1,342	)	$	133,004


____________

-1	Included are certain medium term notes supported primarily by pools of European investment grade credit with varying degrees of leverage. The notes had a fair value of $79.9 million and $154.6 million and an amortized cost of $68.4 million and $147.7 million at December 31, 2014 and December 31, 2013, respectively. These notes allow the investor to participate in cash flows of the underlying bonds including certain residual values, which could serve to either decrease or increase the ultimate values of these notes.

-2	Short-term investments consist primarily of Corporate securities and U.S. and Non-U.S. Government and Government-Related/ Supported securities.

-3	Cash equivalents balances subject to fair value measurement include certificates of deposit and money market funds. Operating cash balances are not subject to recurring fair value measurement guidance.

-4	The Other investments balance excludes certain structured transactions including certain investments in project finance transactions, a payment obligation and liquidity financing provided to a structured credit vehicle as a part of a third party medium term note facility. These investments, which totaled $354.4 million at December 31, 2014 and $294.0 million at December 31, 2013, are carried at amortized cost. For further information, see Note 8, “Other Investments.”

-5	Other assets and other liabilities include derivative instruments. The derivative balances included in each category are reported on a gross basis by level with a netting adjustment presented separately in the Collateral and Counterparty Netting column. The fair values of the individual derivative contracts are reported gross in their respective levels based on the fair value hierarchy. For further details regarding derivative fair values and associated collateral received or paid see Note 16, “Derivative Instruments."

-6	Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable) include balances related to the life retrocession embedded derivative, under which all investment results associated with the Life Funds Withheld Assets related the Life Retro Arrangements described in Note 3, "Sale of Life Reinsurance Subsidiary", accrue to the benefit of GCLR.

-7	Financial instruments sold, but not yet purchased, represent “short sales” and are included within “Payable for investments purchased” on the balance sheets.
(b) Level 3 Assets and Liabilities
The tables below present additional information about assets and liabilities measured at fair value on a recurring basis and for which Level 3 inputs were utilized to determine fair value. The tables present a reconciliation of the beginning and ending balances for the years ended December 31, 2014 and 2013 for all financial assets and liabilities measured at fair value using significant unobservable inputs (Level 3) at December 31, 2014 and 2013, respectively. The tables do not include gains or losses that were reported in Level 3 in prior periods for assets that were transferred out of Level 3 prior to December 31, 2014 and 2013. Gains and losses for assets and liabilities classified within Level 3 in the table below may include changes in fair value that are attributable to both observable inputs (Levels 1 and 2) and unobservable inputs (Level 3). Further, it should be noted that the following tables do not take into consideration the effect of offsetting Level 1 and 2 financial instruments entered into by the Company that are either economically hedged by certain exposures to the Level 3 positions or that hedge the exposures in Level 3 positions.
In general, Level 3 assets include securities for which values were obtained from brokers where either significant inputs were utilized in determining the values that were difficult to corroborate with observable market data, or sufficient information regarding the specific inputs utilized by the broker was not available to support a Level 2 classification. Transfers into or out of Level 3 primarily arise as a result of the valuations utilized by the Company changing between either those provided by independent pricing services that do not contain significant unobservable inputs and other valuations sourced from brokers that are considered Level 3.
There were no significant transfers between Level 1 and Level 2 during the years ended December 31, 2014 and 2013.


(U.S. dollars in thousands)	Level 3 Assets and Liabilities – Year Ended December 31, 2014
	Corporate			RMBS – Agency			RMBS –			CMBS			CDO
							Non Agency
Balance, beginning of period	$	31,573		$	10,473		$	9		$	12,533		$	710,253

Realized gains (losses)	199			5			1			3			3,781

Movement in unrealized gains (losses)	(128		)	(18		)	1			(3		)	11,604

Purchases and issuances	3,759			120			—			1,376			185,710

Sales	—			—			—			—			(48,313		)

Settlements	(6,543		)	(3,205		)	(11		)	(12,533		)	(175,077		)
Transfers into Level 3	766			—			—			—			—

Transfers out of Level 3	(23,732		)	(5,465		)	—			(1,376		)	—

Fixed maturities to short-term investments classification change	—			—			—			—			—

Balance, end of period	$	5,894		$	1,910		$	—		$	—		$	687,958

Movement in total gains (losses) above relating to instruments still held at the reporting date	$	60		$	(12	)	$	—		$	—		$	14,432




(U.S. dollars in thousands)	Level 3 Assets and Liabilities – Year Ended December 31, 2014
	Other asset-			Non-US Sovereign			Short-term			Other			Derivative
	backed			Government,			investments			investments			Contracts – Net
	securities			Provincial,
				Supranational and
				Government
				Related/Supported
Balance, beginning of period	$	11,877		$	—		$	2,015		$	113,472		$	(29,110	)

Realized gains (losses)	(7		)	—			—			12,676			—

Movement in unrealized gains (losses)	65			—			(15		)	538			19,346

Purchases and issuances	5,182			—			—			59,401			—

Sales	—			—			—			—			—

Settlements	(5,705		)	—			(2,000		)	(25,498		)	—

Transfers into Level 3	—			—			—			24,494			—

Transfers out of Level 3	(6,124		)	—			—						—

Fixed maturities to short-term investments classification change	—			—			—			—			—

Balance, end of period	$	5,288		$	—		$	—		$	185,083		$	(9,764	)

Movement in total gains (losses) above relating to instruments still held at the reporting date	$	57		$	—		$	—		$	13,212		$	19,346





(U.S. dollars in thousands)	Level 3 Assets and Liabilities – Year Ended December 31, 2013
	Corporate			RMBS – Agency			RMBS –			CMBS			CDO
							Non Agency
Balance, beginning of period	$	30,098		$	32,005		$	116		$	25,347		$	701,736

Realized gains (losses)	4			10			(1		)	3			4,364

Movement in unrealized gains (losses)	766			(23		)	(1		)	(68		)	37,916

Purchases and issuances	10,691			—			3,326			—			136,035

Sales	(71		)	(535		)	—			—			(48,226		)

Settlements	(7,274		)	(3,349		)	(105		)	(12,749		)	(121,572		)
Transfers into Level 3	—			—			—			—			—

Transfers out of Level 3	(2,641		)	(17,635		)	(3,326		)	—			—

Fixed maturities to short-term investments classification change	—			—			—			—			—

Balance, end of period	$	31,573		$	10,473		$	9		$	12,533		$	710,253

Movement in total gains (losses) above relating to instruments still held at the reporting date	$	845		$	(27	)	$	(1	)	$	(65	)	$	39,259




(U.S. dollars in thousands)	Level 3 Assets and Liabilities – Year Ended December 31, 2013
	Other asset-			Non-US Sovereign			Short-term			Other			Derivative
	backed			Government,			investments			investments			Contracts – Net
	securities			Provincial,
				Supranational and
				Government
				Related/Supported
Balance, beginning of period	$	18,128		$	—		$	—		$	115,272		$	(36,247	)

Realized gains (losses)	848			—			(17		)	7,545			—

Movement in unrealized gains (losses)	1,691			—			15			4,095			7,137

Purchases and issuances	21,686			—			2,017			18,340			—

Sales	(15,711		)	—			—			(1,237		)	—

Settlements	(8,259		)	—			—			(30,543		)	—

Transfers into Level 3	—			—			—			—			—

Transfers out of Level 3	(6,506		)	—			—			—			—

Fixed maturities to short-term investments classification change	—			—			—			—			—

Balance, end of period	$	11,877		$	—		$	2,015		$	113,472		$	(29,110	)

Movement in total gains (losses) above relating to instruments still held at the reporting date	$	(515	)	$	—		$	(2	)	$	10,750		$	7,137

(c) Fixed maturities and short-term investments
The Company’s Level 3 assets consist primarily of CDOs, for which non-binding broker quotes are the primary source of the valuations. Sufficient information regarding the specific inputs utilized by the brokers was not available to support a Level 2 classification. The Company obtains the majority of broker quotes for these CDOs from third party investment managers who perform independent verifications of these valuations using pricing matrices based upon information gathered by market traders. In addition, for the majority of these securities, the Company compares the broker quotes to independent valuations obtained from third party pricing vendors, which may also consist of broker quotes, to assess if the prices received represent a reasonable estimate of the fair value. Although the Company does not have access to the specific unobservable inputs that may have been used in the fair value measurements of the CDO securities provided by brokers, we would expect that the significant inputs considered are prepayment rates, probability of default, loss severity in the event of default, recovery rates, liquidity premium and reinvestment rates. Significant increases (decreases) in any of those inputs in isolation could result in a significantly different fair value measurement. Generally, a change in the assumption used for the probability of default is accompanied by a directionally similar change in the assumption used for the loss severity and a directionally opposite change in the assumption used for prepayment rates.
The remainder of the Level 3 assets relate primarily to private investment funds and certain derivative positions as described below.
(d) Other investments
Included within the Other investments component of the Company’s Level 3 valuations are private investments and alternative fund investments where the Company is not deemed to have significant influence over the investee. The fair value of these investments is based upon net asset values received from the investment manager or general partner of the respective entity. The nature of the underlying investments held by the investee that form the basis of the net asset value include assets such as private business ventures and are such that significant Level 3 inputs are utilized in the determination of the individual underlying holding values and, accordingly, the fair value of the Company’s investment in each entity is classified within Level 3. The Company has not adjusted the net asset values received; however, management incorporates factors such as the most recent financial information received, annual audited financial statements and the values at which capital transactions with the investee take place when applying judgment regarding whether any adjustments should be made to the net asset value in recording the fair value of each position. Investments in alternative funds included in Other investments utilize strategies including arbitrage, directional, event driven and multi-style. These funds potentially have lockup and gate provisions which may limit redemption liquidity. For further details regarding the nature of Other investments and related features, see Note 8, “Other Investments,” for further details.
(e) Derivative instruments
Derivative instruments recorded within Other liabilities and classified within Level 3 include credit derivatives sold providing protection on senior tranches of structured finance transactions where the value is obtained directly from the investment bank counterparty and sufficient information regarding the inputs utilized in such valuation was not obtained to support a Level 2 classification and guaranteed minimum income benefits embedded within one reinsurance contract. The majority of inputs utilized in the valuations of these types of derivative contracts are considered Level 1 or Level 2; however, each valuation includes at least one Level 3 input that was significant to the valuation and, accordingly, the values are disclosed within Level 3.
The calculation of the change in fair value of the embedded derivative associated with the Life Retro Arrangements includes the interest income, realized and unrealized gains and losses on Life Funds Withheld Assets and certain related expenses related to the Life Funds Withheld Assets. The fair value of the embedded derivative is included in “Funds withheld on life retrocession arrangements, net of future policy benefit reserves recoverable” on the consolidated balance sheets. The fair value of the embedded derivative is considered a Level 2 valuation.
(f) Financial Instruments Not Carried at Fair Value
Authoritative guidance over disclosures about the fair value of financial instruments requires additional disclosure of fair value information for financial instruments not carried at fair value in both interim and annual reporting periods. Certain financial instruments, particularly insurance contracts, are excluded from these fair value disclosure requirements. The carrying values of cash and cash equivalents, accrued investment income, net receivable from investments sold, other assets, net payable for investments purchased, other liabilities and other financial instruments not included below approximated their fair values. The following table includes financial instruments for which the carrying value differs from the estimated fair values at December 31, 2014 and 2013. All of these fair value estimates are considered Level 2 fair value measurements. The fair values for fixed maturities held to maturity are provided by third party pricing vendors and significant valuation inputs for all other items included were based upon market data obtained from sources independent of the Company, and are subject to the same control environment previously described.


(U.S. dollars in thousands)	2014						2013
	Carrying Value			Fair Value			Carrying Value			Fair Value
Fixed maturities, held to maturity	$	—		$	—		$	2,858,695		$	3,131,235

Other investments – structured transactions and other	354,382			371,625			294,048			296,799

Financial Assets	$	354,382		$	371,625		$	3,152,743		$	3,428,034

Deposit liabilities	$	1,245,367		$	1,543,761		$	1,509,243		$	1,718,394

Notes payable and debt	1,662,580			1,897,854			2,263,203			2,429,412

Financial Liabilities	$	2,907,947		$	3,441,615		$	3,772,446		$	4,147,806

As described in Note 3, "Sale of Life Reinsurance Subsidiary," certain fixed maturities were reclassified from held to maturity to available for sale. See also Note 6, "Investments," for further information.
The Company historically participated in structured transactions. Remaining structured transactions include cash loans supporting project finance transactions, a liquidity facility financing provided to structured project deals and an investment in a payment obligation with an insurance company. These transactions are carried at amortized cost. The fair value of these investments held by the Company is determined through use of internal models utilizing reported trades, benchmark yields, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers and reference data.
Deposit liabilities include obligations under structured insurance and reinsurance transactions. For purposes of fair value disclosures, the Company determined the estimated fair value of the deposit liabilities by assuming a discount rate equal to the appropriate U.S. Treasury rate plus 29.5 basis points and 56.7 basis points at December 31, 2014 and 2013, respectively. The discount rate incorporates the Company’s own credit risk into the determination of estimated fair value.
The fair values of the Company’s notes payable and debt outstanding were determined based on quoted market prices.
There are no significant concentrations of credit risk within the Company’s financial instruments as defined in the authoritative guidance over disclosures of fair value of financial instruments not carried at fair value, which excludes certain financial instruments, particularly insurance contracts.

Segment_Information

Segment Information	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Segment Information	Segment Information
	The Company is organized into two operating segments: Insurance and Reinsurance. Subsequent to the transaction as described in Note 3, "Sale of Life Reinsurance Subsidiary," GCLR reinsures the majority of the Company's life reinsurance business through the Life Retro Arrangements. The Company no longer considers the Life Operations to be a separate operating segment and the results of the Run-Off Life Operations are reported within “Corporate and Other.” The Company’s general investment and financing operations are also reflected in Corporate and Other. The run-off business subject to the Life Retro Arrangements was, prior to June 30, 2014, reported within the Company’s Life operations segment. Prior period information has been recast to reflect the current presentation.
	The Company evaluates the performance of both the Insurance and Reinsurance segments based on underwriting profit. Other items of revenue and expenditure of the Company are not evaluated at the segment level. In addition, the Company does not allocate investment assets used to support its Property and Casualty (“P&C”) operations to the individual segments, except as noted below. Investment assets related to the Company’s Run-Off Life Operations and certain structured products included in the Insurance and Reinsurance segments are held in separately identified portfolios. As such, net investment income from these assets is included in the contribution from the applicable segment or in Corporate and Other. The following tables summarize the segment results for the indicated years ended:


	Year Ended December 31, 2014	Insurance				Reinsurance				Total P&C				Corporate and Other (1)				Total
	(U.S. dollars in thousands, except ratios)
	Gross premiums written	$	5,976,011			$	1,785,479			$	7,761,490			$	333,436			$	8,094,926

	Net premiums written	4,134,151				1,633,058				5,767,209				177,632				5,944,841

	Net premiums earned	4,026,713				1,690,725				5,717,438				177,632				5,895,070

	Net losses and loss expenses	2,543,108				715,285				3,258,393				242,963				3,501,356

	Acquisition costs	393,319				330,684				724,003				14,115				738,118

	Operating expenses (2)	865,592				193,404				1,058,996				10,693				1,069,689

	Underwriting profit (loss)	$	224,694			$	451,352			$	676,046			$	(90,139	)		$	585,907

	Net investment income - excluding Life Funds Withheld Assets (3)									574,458				146,558				721,016

	Net investment income - Life Funds Withheld Assets													129,575				129,575

	Net results from structured products (4)	43,710				10,499				54,209				—				54,209

	Net fee income and other (5)	(10,051		)		2,800				(7,251		)		360				(6,891		)

	Loss on sale of life reinsurance subsidiary									—				666,423				666,423

	Net realized gains (losses) on investments - excluding Life Funds Withheld Assets									119,366				3,625				122,991

	Net realized gains (losses) on investments and net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets									—				(15,529		)		(15,529		)

	Net realized and unrealized gains (losses) on derivative instruments									—				29,886				29,886

	Net realized and unrealized gains (losses) on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets									—				(488,222		)		(488,222		)

	Net income (loss) from investment fund affiliates and operating affiliates (6)									—				203,034				203,034

	Exchange (gains) losses									—				(37,568		)		(37,568		)

	Corporate operating expenses									—				220,165				220,165

	Contribution from P&C and Corporate and Other									1,416,828				(929,872		)		486,956

	Interest expense (7)													121,221				121,221

	Non-controlling interests													80,498				80,498

	Income tax expense													96,897				96,897

	Net income (loss) attributable to ordinary shareholders																	$	188,340

	Ratios – P&C operations: (8)
	Loss and loss expense ratio	63.2		%		42.3		%		57		%
	Underwriting expense ratio	31.2		%		31		%		31.2		%
	Combined ratio	94.4		%		73.3		%		88.2		%
	____________

	-1	Corporate and Other includes other items of our revenue and expenditures that are not evaluated at the segment level for reporting purposes, as well as the Company's Run-Off Life Operations.

	-2	Operating expenses of the segments exclude Corporate operating expenses, shown separately.

-3	Net investment income - excluding Life Funds Withheld Assets does not include net investment income related to the net results from structured products.

-4	The net results from P&C structured products include net investment income and interest expense of $68.0 million and $12.9 million, respectively.

-5	Net fee income and other includes operating expenses from the Company's loss prevention consulting services business.

-6	The Company generally records the income related to the alternative funds and to the private investment and operating fund affiliates on a one-month and three-month lag, respectively.

-7	Interest expense excludes interest expense related to deposit liabilities recorded in the Insurance and Reinsurance segments.

-8	Ratios are based on net premiums earned from P&C operations.



Year Ended December 31, 2013	Insurance				Reinsurance				Total P&C				Corporate & Other (1)				Total
(U.S. dollars in thousands, except ratios)
Gross premiums written	$	5,523,181			$	1,893,611			$	7,416,792			$	324,343			$	7,741,135

Net premiums written	4,154,093				1,749,889				5,903,982				295,422				6,199,404

Net premiums earned	4,267,677				1,746,422				6,014,099				295,422				6,309,521

Net losses and loss expenses	2,829,999				901,465				3,731,464				465,702				4,197,166

Acquisition costs	529,270				353,388				882,658				26,665				909,323

Operating expenses (2)	782,677				166,238				948,915				8,926				957,841

Underwriting profit (loss)	$	125,731			$	325,331			$	451,062			$	(205,871	)		$	245,191

Net investment income (3)									599,144				286,645				885,789

Net results from structured products (4)	15,562				8,229				23,791				—				23,791

Net fee income and other (5)	(9,317		)		2,320				(6,997		)		1,305				(5,692		)

Net realized gains (losses) on investments									85,792				1,985				87,777

Net realized and unrealized gains (losses) on derivative instruments									—				7,798				7,798

Net income (loss) from investment fund affiliates and operating affiliates (6)									—				258,195				258,195

Exchange (gains) losses									—				(28,243		)		(28,243		)

Corporate operating expenses									—				209,454				209,454

Contribution from P&C and Corporate and Other									1,152,792				168,846				1,321,638

Interest expense (7)													107,486				107,486

Non-controlling interests													76,731				76,731

Income tax expense													77,505				77,505

Net income (loss) attributable to ordinary shareholders																	$	1,059,916

Ratios – P&C operations: (8)
Loss and loss expense ratio	66.3		%		51.6		%		62		%
Underwriting expense ratio	30.8		%		29.8		%		30.5		%
Combined ratio	97.1		%		81.4		%		92.5		%
____________

-1	Corporate and Other includes other items of our revenue and expenditures that are not evaluated at the segment level for reporting purposes, as well as the Company's Run-Off Life Operations.

-2	Operating expenses of the segments exclude Corporate operating expenses, shown separately.

-3	Net investment income does not include net investment income related to the net results from structured products.

-4	The net results from P&C structured products include net investment income and interest expense of $71.9 million and $48.0 million, respectively.

-5	Net fee income and other includes operating expenses from the Company's loss prevention consulting services business.

-6	The Company generally records the income related to the alternative funds and to the private investment and operating fund affiliates on a one-month and three-month lag, respectively.

-7	Interest expense excludes interest expense related to deposit liabilities recorded in the Insurance and Reinsurance segments.

-8	Ratios are based on net premiums earned from P&C operations.




Year Ended December 31, 2012	Insurance				Reinsurance				Total P&C				Corporate and Other (1)				Total
(U.S. dollars in thousands, except ratios)
Gross premiums written	$	5,166,973			$	2,008,157			$	7,175,130			$	355,753			$	7,530,883

Net premiums written	4,072,511				1,884,508				5,957,019				324,432				6,281,451

Net premiums earned	3,924,636				1,841,342				5,765,978				324,459				6,090,437

Net losses and loss expenses	2,691,056				1,074,426				3,765,482				486,195				4,251,677

Acquisition costs	504,227				368,172				872,399				41,093				913,492

Operating expenses (2)	754,308				157,657				911,965				9,335				921,300

Underwriting profit (loss)	$	(24,955	)		$	241,087			$	216,132			$	(212,164	)		$	3,968

Net investment income (3)									641,237				299,443				940,680

Net results from structured products (4)	20,978				(15,721		)		5,257				—				5,257

Net fee income and other (5)	850				2,492				3,342				426				3,768

Net realized gains (losses) on investments									35,101				(21,003		)		14,098

Net realized and unrealized gains (losses) on derivative instruments									—				5,221				5,221

Net income (loss) from investment fund affiliates and operating affiliates (6)									—				112,391				112,391

Exchange (gains) losses									—				10,545				10,545

Corporate operating expenses									—				204,502				204,502

Contribution from P&C and Corporate and Other									901,069				(30,733		)		870,336

Interest expense (7)													105,925				105,925

Non-controlling interests													79,255				79,255

Income tax expense													34,028				34,028

Net income (loss) attributable to ordinary shareholders																	$	651,128

Ratios – P&C operations: (8)
Loss and loss expense ratio	68.6		%		58.4		%		65.3		%
Underwriting expense ratio	32		%		28.5		%		31		%
Combined ratio	100.6		%		86.9		%		96.3		%

____________

-1	Corporate and Other includes other items of our revenue and expenditures that are not evaluated at the segment level for reporting purposes, as well as the Company's Run-Off Life Operations.

-2	Operating expenses exclude Corporate operating expenses, shown separately.

-3	Net investment income does not include net investment income related to the net results from structured products.

-4	The net results from P&C structured products include net investment income and interest expense of $71.7 million and $66.3 million, respectively.

-5	Net fee income and other includes operating expenses from the Company's loss prevention consulting services business.

-6	The Company generally records the income related to the alternative funds and to the private investment and operating fund affiliates on a one-month and three-month lag, respectively.

-7	Interest expense excludes interest expense related to deposit liabilities recorded in the Insurance and Reinsurance segments.

-8	Ratios are based on net premiums earned from P&C operations.
The following tables summarize the Company’s net premiums earned by line of business:


Year Ended December 31, 2014	Insurance				Reinsurance				Corporate and Other				Total
(U.S. dollars in thousands)
P&C Operations:
Professional	$	1,075,420			$	181,223			$	—			$	1,256,643

Casualty	1,422,684				300,223				—				1,722,907

Property catastrophe	—				433,602				—				433,602

Property	544,856				555,583				—				1,100,439

Marine, energy, aviation and satellite	—				95,745				—				95,745

Specialty	737,281				—				—				737,281

Other (1)	246,472				124,349				—				370,821

Total P&C Operations	$	4,026,713			$	1,690,725			$	—			$	5,717,438

Corporate and Other:
Run-Off Life Operations - Annuity	—				—				53,363				53,363

Run-Off Life Operations - Other Life	—				—				124,269				124,269

Total Corporate and Other	$	—			$	—			$	177,632			$	177,632

Total	$	4,026,713			$	1,690,725			$	177,632			$	5,895,070

Year Ended December 31, 2013
P&C Operations:
Professional	$	1,370,196			$	206,169			$	—			$	1,576,365

Casualty	1,389,851				312,156				—				1,702,007

Property catastrophe	—				492,568				—				492,568

Property	544,278				561,105				—				1,105,383

Marine, energy, aviation and satellite	—				94,797				—				94,797

Specialty	732,042				—				—				732,042

Other (1)	231,310				79,627				—				310,937

Total P&C Operations	$	4,267,677			$	1,746,422			$	—			$	6,014,099

Corporate and Other:
Run-Off Life Operations - Annuity	$	—			$	—			$	122,715			$	122,715

Run-Off Life Operations - Other Life	—				—				172,707				172,707

Total Corporate and Other	$	—			$	—			$	295,422			$	295,422

Total	$	4,267,677			$	1,746,422			$	295,422			$	6,309,521

Year Ended December 31, 2012
P&C Operations:
Professional	$	1,350,319			$	213,324			$	—			$	1,563,643

Casualty	1,165,753				311,166				—				1,476,919

Property catastrophe	—				463,975				—				463,975

Property	489,739				613,291				—				1,103,030

Marine, energy, aviation and satellite	—				147,362				—				147,362

Specialty	708,568				—				—				708,568

Other (1)	210,257				92,224				—				302,481

Total P&C Operations	$	3,924,636			$	1,841,342			$	—			$	5,765,978

Corporate and Other:
Run-Off Life Operations - Annuity	$	—			$	—			$	126,912			$	126,912

Run-Off Life Operations - Other Life	—				—				197,547				197,547

Total Corporate and Other	$	—			$	—			$	324,459			$	324,459

Total	$	3,924,636			$	1,841,342			$	324,459			$	6,090,437

____________

-1	Other within the Insurance segment includes: excess and surplus, programs, surety, structured indemnity and certain discontinued lines. Other within the Reinsurance segment includes: whole account contracts, accident and health and other lines.
The following table shows an analysis of the Company’s net premiums written by geographical location of subsidiary where the premium is written for the years ended December 31:


(U.S. dollars in thousands)	2014				2013				2012
P&C Operations:
Bermuda	$	636,109			$	658,041			$	644,566

United States	2,528,196				2,650,916				2,626,855

Europe	2,124,117				2,111,065				2,202,209

Other	478,787				483,960				483,389

Total P&C Operations	$	5,767,209			$	5,903,982			$	5,957,019

Corporate and Other:
Bermuda	$	91,979			$	117,948			$	129,997

Europe	85,653				177,474				194,435

Total Corporate and Other	$	177,632			$	295,422			$	324,432

Investments

Investments	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Investments	Investments
	(a) Fixed Maturities, Short-Term Investments and Equity Securities
	Classification of Fixed Income Securities
	During the second quarter of 2014, fixed maturities with a carrying value of $2.8 billion were reclassified from held to maturity ("HTM") to AFS in conjunction with the sale of XLLR as discussed in Note 3, “Sale of Life Reinsurance Subsidiary.” Gross unrealized gains and gross unrealized losses, net of tax, of $424.9 million and nil, respectively, related to these securities were recognized in other comprehensive income on the date of transfer. For certain annuity contracts that are subject to the Life Retro Arrangements, policy benefit reserves were historically increased for the impact of changes in unrealized gains on investments supporting such contracts as if the gains had been realized, with a corresponding entry to other comprehensive income ("Shadow Adjustments"). In conjunction with the sale of XLLR and the related reclassification of securities from HTM to AFS, the Company recorded an additional gross charge of $440.5 million, net of tax, as a reduction of comprehensive income for such Shadow Adjustments on the date of the transfer. See Note 22, "Accumulated Other Comprehensive Income (Loss)" for further information.
	All of the reclassified securities are included within the Life Funds Withheld Assets, along with certain other available for sale securities as defined in the sale and purchase agreement. The Life Funds Withheld Assets are managed pursuant to agreed investment guidelines that meet the contractual commitments of the XL ceding companies and applicable laws and regulations. All of the investment results associated with the Life Funds Withheld Assets ultimately accrue to GCLR. Because the Company no longer shares in the risks and rewards of the underlying performance of the Life Funds Withheld Assets, disclosures within the financial statements and accompanying notes included herein separate the Life Funds Withheld Assets from the rest of the Company's investments.
	Amortized Cost and Fair Value Summary
	The cost (amortized cost for fixed maturities and short-term investments), fair value, gross unrealized gains and gross unrealized (losses), including OTTI recorded in accumulated other comprehensive income (“AOCI”) of the Company’s AFS and HTM investments at December 31, 2014 and 2013, were as follows:


					Included in AOCI
	31-Dec-14	Cost or			Gross			Gross Unrealized Losses				Fair Value			Non-credit Related OTTI (1)
	(U.S. dollars in thousands)	Amortized			Unrealized
		Cost			Gains
	Fixed maturities - AFS
	U.S. Government and Government-Related/Supported	$	2,100,851		$	77,889		$	(6,787	)		$	2,171,953		$	—

	Corporate (2)	8,462,130			365,805			(49,562		)		8,778,373			(3,309		)

	RMBS – Agency	3,625,171			114,188			(10,783		)		3,728,576			—

	RMBS – Non-Agency	404,398			41,108			(18,155		)		427,351			(67,918		)

	CMBS	1,033,819			23,987			(5,262		)		1,052,544			(2,033		)

	CDO	717,544			1,659			(27,169		)		692,034			(1,663		)

	Other asset-backed securities (2)	1,028,528			42,810			(6,045		)		1,065,293			(1,797		)

	U.S. States and political subdivisions of the States	1,892,566			129,910			(1,204		)		2,021,272			—

	Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	4,162,425			139,484			(61,836		)		4,240,073			—

	Total fixed maturities - AFS - Excluding Life Funds Withheld Assets	$	23,427,432		$	936,840		$	(186,803	)		$	24,177,469		$	(76,720	)

	Total short-term investments	257,221			49			(543		)		256,727			—

	Total equity securities	763,833			130,689			(26,230		)		868,292			—

	Total investments - AFS - Excluding Life Funds Withheld Assets	$	24,448,486		$	1,067,578		$	(213,576	)		$	25,302,488		$	(76,720	)

	Fixed maturities - AFS - Life Funds Withheld Assets

	U.S. Government and Government-Related/Supported	$	14,866		$	3,858		$	—			$	18,724		$	—

	Corporate	2,407,849			410,131			—				2,817,980			—

	RMBS – Agency	3,301			481			—				3,782			—

	RMBS – Non-Agency	71,075			14,260			—				85,335			—

	CMBS	168,886			24,281			—				193,167			—

	CDO	—			—			—				—			—

	Other asset-backed securities	238,168			35,373			—				273,541			—

	U.S. States and political subdivisions of the States	—			—			—				—			—

	Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	1,397,194			391,842			—				1,789,036			—

	Total fixed maturities - AFS - Life Funds Withheld Assets	$	4,301,339		$	880,226		$	—			$	5,181,565		$	—

	Total investments - AFS	$	28,749,825		$	1,947,804		$	(213,576	)		$	30,484,053		$	(76,720	)

Total fixed maturities - HTM	$	—		$	—		$	—			$	—		$	—


31-Dec-14											Amortized			Fair Value
(U.S. dollars in thousands)											Cost
Fixed maturities - Trading - Life Funds Withheld Assets

Corporate											1,180			1,171

Total investments - Trading - Life Funds Withheld Assets											$	1,180		$	1,171


____________

-1	Represents the non-credit component of OTTI losses, adjusted for subsequent sales of securities. It does not include the change in fair value subsequent to the impairment measurement date.

-2	Included are certain medium term notes supported primarily by pools of European investment grade credit with varying degrees of leverage. The notes have a fair value of $79.9 million and an amortized cost of $68.4 million. These notes allow the investor to participate in cash flows of the underlying bonds including certain residual values, which could serve to either decrease or increase the ultimate values of these notes.




				Included in AOCI
31-Dec-13	Cost or			Gross			Gross Unrealized Losses				Fair Value			Non-credit Related OTTI (1)
(U.S. dollars in thousands)	Amortized			Unrealized
	Cost			Gains
Fixed maturities - AFS
U.S. Government and Government-Related/Supported	$	2,484,193		$	51,701		$	(34,043	)		$	2,501,851		$	—

Corporate (2)	10,802,332			433,097			(109,599		)		11,125,830			(4,758		)

RMBS – Agency	3,540,101			68,098			(62,077		)		3,546,122			—

RMBS – Non-Agency	396,798			33,096			(31,126		)		398,768			(74,528		)

CMBS	1,223,313			39,255			(15,773		)		1,246,795			(2,753		)

CDO	754,414			5,833			(42,934		)		717,313			(2,036		)

Other asset-backed securities (2)	1,210,384			40,560			(8,840		)		1,242,104			(2,807		)

U.S. States and political subdivisions of the States	1,821,499			55,083			(30,770		)		1,845,812			—

Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	4,878,840			80,961			(84,260		)		4,875,541			—

Total fixed maturities - AFS	$	27,111,874		$	807,684		$	(419,422	)		$	27,500,136		$	(86,882	)

Total short-term investments	455,470			962			(144		)		456,288			—

Total equity securities	903,201			154,506			(17,470		)		1,040,237			—

Total investments - AFS	$	28,470,545		$	963,152		$	(437,036	)		$	28,996,661		$	(86,882	)

Fixed maturities - HTM
U.S. Government and Government-Related/Supported	$	10,993		$	629		$	—			$	11,622		$	—

Corporate	1,386,863			113,179			(968		)		1,499,074			—

RMBS – Non-Agency	66,987			4,985			—				71,972			—

CMBS	144,924			11,864			—				156,788			—

Other asset-backed securities	106,540			6,908			—				113,448			—

Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	1,142,388			136,585			(642		)		1,278,331			—

Total investments - HTM	$	2,858,695		$	274,150		$	(1,610	)		$	3,131,235		$	—


____________

-1	Represents the non-credit component of OTTI losses, adjusted for subsequent sales of securities. It does not include the change in fair value subsequent to the impairment measurement date.

-2	Included are certain medium term notes supported primarily by pools of European investment grade credit with varying degrees of leverage. The notes have a fair value of $154.6 million and an amortized cost of $147.7 million. These notes allow the investor to participate in cash flows of the underlying bonds including certain residual values, which could serve to either decrease or increase the ultimate values of these notes.
At December 31, 2014 and 2013, approximately 3.0% and 2.6%, respectively, of the Company's fixed income investment portfolio at fair value, excluding Life Funds Withheld Assets, was invested in securities that were below investment grade or not rated. Approximately 24.9% and 12.4% of the gross unrealized losses in the Company's fixed income investment portfolio, excluding Life Funds Withheld Assets, at December 31, 2014 and 2013, respectively, related to securities that were below investment grade or not rated.
Contractual Maturities Summary
The contractual maturities of AFS and HTM fixed income securities at December 31, 2014 and 2013 are shown below. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.


(U.S. dollars in thousands)	31-Dec-14						31-Dec-13
	Amortized			Fair			Amortized				Fair
	Cost			Value			Cost				Value
Fixed maturities - AFS
Due less than one year	$	1,972,224		$	1,980,429		$	2,052,251			$	2,060,365

Due after 1 through 5 years	8,919,037			9,113,651			10,075,087				10,305,986

Due after 5 through 10 years	4,232,396			4,412,569			5,474,120				5,507,450

Due after 10 years	1,494,315			1,705,022			2,385,406				2,475,233

	$	16,617,972		$	17,211,671		$	19,986,864			$	20,349,034

RMBS – Agency	$	3,625,171		$	3,728,576		$	3,540,101			$	3,546,122

RMBS – Non-Agency	404,398			427,351			396,798				398,768

CMBS	1,033,819			1,052,544			1,223,313				1,246,795

CDO	717,544			692,034			754,414				717,313

Other asset-backed securities	1,028,528			1,065,293			1,210,384				1,242,104

Total mortgage and asset-backed securities	$	6,809,460		$	6,965,798		$	7,125,010			$	7,151,102

Total fixed maturities - AFS	$	23,427,432		$	24,177,469		$	27,111,874			$	27,500,136

Fixed maturities - AFS - Life Funds Withheld Assets
Due less than one year	$	117,048		$	125,326		$	—			$	—

Due after 1 through 5 years	638,526			685,787			—				—

Due after 5 through 10 years	1,004,698			1,165,348			—				—

Due after 10 years	2,059,637			2,649,279			—				—

	$	3,819,909		$	4,625,740		$	—			$	—

RMBS – Agency	$	3,301		$	3,782		$	—			$	—

RMBS – Non-Agency	71,075			85,335			—				—

CMBS	168,886			193,167			—				—

CDO	—			—			—				—

Other asset-backed securities	238,168			273,541			—				—

Total mortgage and asset-backed securities	$	481,430		$	555,825		$	—			$	—

Total fixed maturities - AFS - Life Funds Withheld Assets	$	4,301,339		$	5,181,565		$	—			$	—

Total fixed maturities - AFS	$	27,728,771		$	29,359,034		$	27,111,874			$	27,500,136

Fixed maturities - Trading - Life Funds Withheld Assets
Due less than one year	$	—		$	—		$	—			$	—

Due after 1 through 5 years	—			—			—				—

Due after 5 through 10 years	1,180			1,171			—				—

Due after 10 years	—			—			—				—

Total fixed maturities - Trading - Life Funds Withheld Assets	$	1,180		$	1,171		$	—			$	—

Fixed maturities - HTM
Due less than one year	$	—		$	—		$	65,651			$	66,766

Due after 1 through 5 years	—			—			240,802				255,322

Due after 5 through 10 years	—			—			455,633				492,095

Due after 10 years	—			—			1,778,158				1,974,844

	$	—		$	—		$	2,540,244			$	2,789,027

RMBS – Non-Agency	—			—			66,987				71,972

CMBS	—			—			144,924				156,788

Other asset-backed securities	—			—			106,540				113,448

Total mortgage and asset-backed securities	$	—		$	—		$	318,451			$	342,208

Total fixed maturities - HTM	$	—		$	—		$	2,858,695			$	3,131,235


OTTI Considerations
Under final authoritative accounting guidance, a debt security for which amortized cost exceeds fair value is deemed to be other-than-temporarily impaired if it meets either of the following conditions: (a) the Company intends to sell, or it is more likely than not that the Company will be required to sell, the security before a recovery in value, or (b) the Company does not expect to recover the entire amortized cost basis of the security. Other than in a situation in which the Company has the intent to sell a debt security or more likely than not will be required to sell a debt security, the amount of the OTTI related to a credit loss on the security is recognized in earnings, and the amount of the OTTI related to other factors (e.g., interest rates, market conditions, etc.) is recorded as a component of OCI. The net amount recognized in earnings (“credit loss impairment”) represents the difference between the amortized cost of the security and the net present value of its projected future cash flows discounted at the effective interest rate implicit in the debt security prior to impairment (“NPV”). The remaining difference between the security's NPV and its fair value is recognized in OCI. Subsequent changes in the fair value of these securities are included in OCI unless a further impairment is deemed to have occurred.
In the scenario where the Company has the intent to sell a security in which its amortized cost exceeds its fair value, or it is more likely than not that it will be required to sell such a security, the entire difference between the security's amortized cost and its fair value is recognized in earnings.
The determination of credit loss impairment is based on detailed analyses of underlying cash flows and other considerations. Such analyses require the use of certain assumptions to develop the estimated performance of underlying collateral. Key assumptions used include, but are not limited to, items such as RMBS default rates based on collateral duration in arrears, severity of losses on default by collateral class, collateral reinvestment rates and expected future general corporate default rates.
Factors considered for all securities on a quarterly basis in determining that a gross unrealized loss is not other-than-temporarily impaired include management's consideration of current and near term liquidity needs and other available sources of funds, an evaluation of the factors and time necessary for recovery and an assessment of whether the Company has the intention to sell or considers it more likely than not that it will be forced to sell a security.
Pledged Assets
Certain of the Company's invested assets are held in trust and pledged in support of insurance and reinsurance liabilities as well as credit facilities. Such pledges are largely required by the Company's operating subsidiaries that are “non-admitted” under U.S. state insurance regulations, in order for the U.S. cedant to receive statutory credit for reinsurance. Also, certain deposit liabilities and annuity contracts require the use of pledged assets. At December 31, 2014 and 2013, the Company had $15.2 billion and $15.5 billion in pledged assets, respectively.
(b) Gross Unrealized Losses
The following is an analysis of how long the AFS and HTM securities at December 31, 2014 and 2013 had been in a continual unrealized loss position:


31-Dec-14	Less than 12 months						Equal to or greater
(U.S. dollars in thousands)							than 12 months
	Fair Value			Gross			Fair Value				Gross
				Unrealized							Unrealized
				Losses							Losses
Fixed maturities and short-term investments - AFS
U.S. Government and Government-Related/Supported	$	251,091		$	(1,196	)	$	342,890			$	(5,603	)

Corporate	1,337,470			(33,881		)	424,221				(15,754		)

RMBS – Agency	134,535			(220		)	512,652				(10,563		)

RMBS – Non-Agency	45,378			(1,358		)	202,700				(16,797		)

CMBS	78,356			(385		)	169,065				(4,877		)

CDO	249,803			(2,666		)	414,516				(24,503		)

Other asset-backed securities	143,044			(2,813		)	57,544				(3,232		)

U.S. States and political subdivisions of the States	32,187			(210		)	63,695				(994		)

Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	624,346			(19,043		)	558,422				(43,251		)

Total fixed maturities and short-term investments - AFS	$	2,896,210		$	(61,772	)	$	2,745,705			$	(125,574	)

Total equity securities	$	191,193		$	(26,230	)	$	—			$	—

Total fixed maturities - HTM	$	—		$	—		$	—			$	—




31-Dec-13	Less than 12 months						Equal to or greater
(U.S. dollars in thousands)							than 12 months
	Fair Value			Gross			Fair Value				Gross
				Unrealized							Unrealized
				Losses							Losses
Fixed maturities and short-term investments - AFS
U.S. Government and Government-Related/Supported	$	1,333,704		$	(30,474	)	$	44,158			$	(3,614	)

Corporate	2,756,235			(59,497		)	513,106				(50,160		)

RMBS – Agency	1,485,261			(50,362		)	169,704				(11,715		)

RMBS – Non-Agency	14,204			(604		)	240,946				(30,522		)

CMBS	432,820			(6,816		)	107,192				(8,957		)

CDO	58,239			(217		)	574,613				(42,717		)

Other asset-backed securities	196,639			(2,149		)	96,528				(6,691		)

U.S. States and political subdivisions of the States	463,974			(23,124		)	64,324				(7,646		)

Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	2,130,792			(56,866		)	306,873				(27,435		)

Total fixed maturities and short-term investments - AFS	$	8,871,868		$	(230,109	)	$	2,117,444			$	(189,457	)

Total equity securities	$	155,453		$	(17,470	)	$	—			$	—

Fixed maturities -HTM
Corporate	$	46,034		$	(941	)	$	642			$	(27	)

Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	—			—			11,894				(642		)

Total fixed maturities - HTM	$	46,034		$	(941	)	$	12,536			$	(669	)

The Company had gross unrealized losses totaling $213.6 million on 1,631 securities out of a total of 7,669 held at December 31, 2014 in its AFS Excluding Life Funds Withheld Assets portfolio, which either it considers to be temporarily impaired or with respect to which it reflects non-credit losses on other-than-temporarily impaired assets. Individual security positions comprising this balance have been evaluated by management to determine the severity of these impairments and whether they should be considered other-than-temporary. Management believes it is more likely than not that the issuer will be able to fund sufficient principal and interest payments to support the current amortized cost.
Management, in its assessment of whether securities in a gross unrealized loss position are temporarily impaired, as described above, considers the significance of the impairments. At December 31, 2014, the AFS Excluding Life Funds Withheld Assets portfolio included structured credit securities with gross unrealized losses of $9.6 million, which had a fair value of $5.5 million, and a cumulative fair value decline of greater than 50% of amortized cost. All of these securities are mortgage and asset-backed securities.
(c) Net Investment Income
Net investment income for the years ended December 31 is derived from the following sources:


(U.S. dollars in thousands)	2014			2013			2012
Fixed maturities, short term investments and cash equivalents - Excluding Life Funds Withheld Assets	$	809,964		$	982,275		$	1,046,255

Fixed maturities, short term investments and cash equivalents - Life Funds Withheld Assets	129,575			—			—

Equity securities and other investments	42,252			35,388			29,807

Funds withheld	14,583			12,783			12,090

Total gross investment income	$	996,374		$	1,030,446		$	1,088,152

Investment expenses	(77,749		)	(72,730		)	(75,804		)
Total net investment income	$	918,625		$	957,716		$	1,012,348

(d) Net Realized Gains (Losses)
The following represents an analysis of net realized gains (losses), the change in unrealized gains (losses) on investments and net realized and unrealized gains (losses) on investment related derivative instruments for the years ended December 31:


(U.S. dollars in thousands)	2014			2013			2012
Net realized gains (losses):
Fixed maturities, short term investments, cash and cash equivalents - Excluding Life Funds Withheld Assets:
Gross realized gains	$	119,817		$	129,479		$	163,328

Gross realized losses on investments sold	(66,892		)	(84,703		)	(107,033		)
OTTI on investments, net of amounts transferred to other comprehensive income	(12,341		)	(16,282		)	(74,245		)
Net realized gains (losses)	$	40,584		$	28,494		$	(17,950	)

Equity securities:
Gross realized gains	$	96,260		$	29,402		$	42,009

Gross realized losses on investments sold	(12,270		)	(3,185		)	(7,121		)
OTTI on investments, net of amounts transferred to other comprehensive income	(10,944		)	(17		)	(3,746		)
Net realized gains (losses)	$	73,046		$	26,200		$	31,142

Other investments:
Gross realized gains	$	31,830		$	46,934		$	11,610

Gross realized losses on investments sold	(10,011		)	(13,851		)	(7,983		)
OTTI on investments, net of amounts transferred to other comprehensive income	(12,458		)	—			(2,721		)

Net realized gains (losses)	$	9,361		$	33,083		$	906

Net realized gains (losses) on investments - Excluding Life Funds Withheld Assets	$	122,991		$	87,777		$	14,098

Fixed maturities, short term investments, cash and cash equivalents - Life Funds Withheld Assets:
Gross realized gains	$	7,926		$	—		$	—

Gross realized losses on investments sold	(2,859		)	—			—

Net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets	(9		)	—			—

OTTI on investments, net of amounts transferred to other comprehensive income	(20,587		)	—			—

Net realized gains (losses) on investments - Life Funds Withheld Assets	$	(15,529	)	$	—		$	—

Net realized gains (losses) on investments	$	107,462		$	87,777		$	14,098

Net realized and unrealized gains (losses) on investment related derivative instruments	$	20,121		$	6,367		$	(1,228	)

Net realized gains (losses) on investments and net realized and unrealized gains (losses) on investment related derivative instruments	$	127,583		$	94,144		$	12,870

Change in unrealized gains (losses):
Fixed maturities – AFS - Excluding Life Funds Withheld Assets	$	360,463		$	(913,174	)	$	884,259

Fixed maturities - AFS - Life Funds Withheld Assets	880,226			—			—

Fixed maturities – HTM	(272,540		)	(175,817		)	221,647

Equity securities	(32,577		)	105,163			44,361

Affiliates and other investments	35,143			26,636			46,163

Net change in unrealized gains (losses) on investments	$	970,715		$	(957,192	)	$	1,196,430

Total net realized gains (losses) on investments, net realized and unrealized gains (losses) on investment related derivative instruments, and net change in unrealized gains (losses) on investments	$	1,098,298		$	(863,048	)	$	1,209,300

The significant components of the net impairment charges of $35.7 million for investments excluding Life Funds Withheld Assets for the year ended December 31, 2014 were:

▪	$12.5 million related to Other Investments.

▪	$10.9 million related to certain equities that were in a loss position for more than 11 months or impaired by more than 50%.

▪	$3.7 million related to change of intent to hold Corporate High Yield securities.

▪	$4.3 million for structured securities, principally non-Agency RMBS, where we determined that the likely recovery on these securities was below the carrying value and, accordingly, recorded an impairment of the securities to the discounted value of the cash flows expected to be received on these securities.

▪	$4.2 million related to foreign exchange losses.
The following table sets forth the amount of credit loss impairments on fixed income securities held by the Company as of the dates or for the periods indicated, for which a portion of the OTTI loss was recognized in OCI, and the corresponding changes in such amounts.


Credit Loss Impairments	2014			2013
(U.S. dollars in thousands)
Opening balance at beginning of indicated period	$	174,805		$	268,708

Credit loss impairment recognized in the current period on securities not previously impaired	3,907			806

Credit loss impairments previously recognized on securities which matured, paid down, prepaid or were sold during the period	(42,671		)	(92,167		)
Credit loss impairments previously recognized on securities impaired to fair value during the period	—			—

Additional credit loss impairments recognized in the current period on securities previously impaired	4,185			11,182

Accretion of credit loss impairments previously recognized due to an increase in cash flows expected to be collected	(8,284		)	(13,724		)
Closing balance at end of indicated period	$	131,942		$	174,805

During the years ended December 31, 2014 and 2013, the $42.7 million and $92.2 million, respectively, credit loss impairments previously recognized on securities that matured, or were paid down, prepaid or sold, includes $9.0 million and $66.1 million, respectively, of non-Agency RMBS.

Investments_in_Affiliates

Investments in Affiliates	12 Months Ended
	Dec. 31, 2014
Equity Method Investments and Joint Ventures [Abstract]
Investments in affiliates	Investments in Affiliates
	The Company’s investment portfolio includes certain investments over which the Company is considered to have significant influence and which, therefore, are accounted for using the equity method. Significant influence is generally deemed to exist where the Company has an investment of 20% or more in the common stock of a corporation or an investment of 3% or more in closed end funds, limited partnerships, LLCs or similar investment vehicles. The Company generally records its alternative and private investment fund affiliates on a one-month and three-month lag, respectively, and its operating affiliates on a three-month lag. See Note 8, “Other Investments,” for information about investments in alternative and private equity funds in which the Company generally owns less than 3% and which the Company accounts for as “Other Investments.”
	Investments in affiliates comprised the following at December 31, 2014 and 2013:


	(U.S. dollars in thousands)	2014			2013
	Investment fund affiliates	$	1,219,138		$	1,042,072

	Operating affiliates	418,482			328,871

	Total investment affiliates	$	1,637,620		$	1,370,943

	(a) Investment Fund Affiliates
	The Company has invested in certain closed end funds, certain limited partnerships, LLCs and similar investment vehicles, including funds managed by certain of its investment manager affiliates. Collectively, these investments in funds, partnerships and other vehicles are classified as “investment fund affiliates.” The Company’s equity investment in investment fund affiliates and equity in net income (loss) from such affiliates as well as certain summarized financial information of the investee as a whole (shown as “Combined Funds”) are included below:


	Year Ended December 31, 2014	XL Group Investment								Combined
	(U.S. dollars in thousands, except percentages)	Carrying			Equity in			Weighted		Funds
		Value			Net Income			Average XL
					(Loss) for			Percentage
					the Year			Ownership		Total Net Assets
										(Estimated) (1)
	Alternative Funds (2):
	Arbitrage	$	134,400		$	12,060		11	%	$	1,224,526

	Directional	536,470			32,196			9.2	%	5,865,247

	Event Driven (3)	300,168			21,030			3.1	%	9,703,973

	Multi-Style	52,122			1,751			4.1	%	1,278,410

	Total alternative funds	$	1,023,160		$	67,037		5.7	%	$	18,072,156

	Private Investment Funds (2):	195,978			28,779			17.7	%	1,105,776

	Total Investment Fund Affiliates	$	1,219,138		$	95,816		6.4	%	$	19,177,932

	Year Ended December 31, 2013
	Alternative Funds (2):
	Arbitrage	$	158,096		$	4,358		3.7	%	$	4,328,748

	Directional	434,652			42,492			8.3	%	5,235,690

	Event Driven (3)	274,380			61,551			2.9	%	9,309,163

	Multi-Style	374			48			15.5	%	2,410

	Total alternative funds	$	867,502		$	108,449		4.6	%	$	18,876,011

	Private Investment Funds (2):	174,570			29,942			19.6	%	890,815

	Total Investment Fund Affiliates	$	1,042,072		$	138,391		5.3	%	$	19,766,826

	____________

	-1	Total estimated net assets are generally as at November 30 for alternative fund affiliates and September 30 for private investment fund affiliates.

	-2	The Company generally records its alternative fund affiliates on a one-month lag and its private investment fund affiliates on a three-month lag.

	-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.
	Certain funds have a lock-up period and/or may also have the ability to impose a redemption gate. A lock-up period refers to the initial amount of time an investor is contractually required to remain invested before having the ability to redeem. Typically, the imposition of a gate delays a portion of the requested redemption, with the remaining portion settled in cash shortly after the redemption date.
	The carrying value of the Company’s holdings in funds that are subject to lockups and/or that have gate provisions in their governing documents at December 31, 2014 and 2013 was $543.0 million and $488.5 million, respectively. The Company did not have any holdings in funds where a gate was imposed at December 31, 2014 or 2013.
	Certain funds may be allowed to invest a portion of their assets in illiquid securities, such as private equity or private debt. In such cases, a common mechanism used is a side-pocket, whereby the illiquid security is assigned to a separate memorandum capital account or other designated account. Typically, the investor loses its redemption rights in the designated account. Only when the illiquid securities in the side-pocket are sold, or otherwise deemed liquid by the fund, may investors redeem that portion of their interest that has been “side-pocketed." At December 31, 2014 and 2013, the carrying value of our funds held in side-pockets was $22.2 million and $42.3 million, respectively. The underlying assets within these positions are generally expected to be liquidated over a period of approximately two to four years.
	(b) Operating Affiliates
The Company has invested in investment and (re)insurance affiliates and investment management companies’ securities or other forms of ownership interests. Collectively, these investments are classified as “operating affiliates.”
The Company’s equity investment in operating affiliates and equity in net income (loss) from such affiliates as well as certain summarized financial information of the investee as a whole are included below:


Year ended December 31, 2014	XL Group Investment						Combined Investee Summarized
(U.S. dollars in thousands)							Financial Data (Estimated) (1)
	Carrying			Equity in			Total			Total		Total		Net Income
	Value			Net Income			Assets			Liabilities		Revenue		(Loss)
				(Loss) for								(Loss)
				the Year
Other strategic operating affiliates	$	317,216		$	50,132		$	4,679,395		$	3,691,173	$	1,075,935	$	152,122

Investment manager affiliates (2)	101,266			57,086			850,666			101,088		579,524		476,841

Total operating affiliates	$	418,482		$	107,218		$	5,530,061		$	3,792,261	$	1,655,459	$	628,963

Year ended December 31, 2013
Other strategic operating affiliates	266,796			41,160			2,646,987			1,888,879		902,522		125,625

Investment manager affiliates (2)	62,075			78,644			922,348			92,574		813,587		710,412

Total operating affiliates	$	328,871		$	119,804		$	3,569,335		$	1,981,453	$	1,716,109	$	836,037

____________

-1	The Company generally records its operating affiliates on a three-month lag. Estimated assets and liabilities are generally at September 30, 2014 and 2013, respectively.

-2	During the years ended December 31, 2014 and 2013, the Company received distributions from its Investment Manager Affiliates of approximately $60.3 million and $28.3 million, respectively.
In certain investments, the carrying value is different from the share of the investee’s underlying net assets. The differences represent goodwill on acquisition, OTTI recorded with respect to the investment, or differences in the retained capital accounts of the various equity holders (including the Company).
See Note 19(c), “Commitments and Contingencies – Investments in Affiliates,” for further information regarding commitments related to investment in affiliates.
Other Strategic Operating Affiliates
At December 31, 2014, the Company’s larger strategic operating affiliates included ARX Holding Corporation ("ARX") and Five Oaks Investment Corp ("Five Oaks"). The Company's investment in ARX was approximately 40% at December 31, 2014 and 2013, respectively.
On December 15, 2014, the Company announced it had entered into a Stock Purchase Agreement to sell its interests in ARX to The Progressive Corporation ("Progressive"). The transaction, which is expected to close in the second quarter of 2015, is subject to receipt of insurance regulatory approvals and satisfaction of other customary closing conditions. For further information, see Note 29, "Subsequent Events".
In May 2012, the Company invested $25.0 million to obtain an approximate 94% interest in Five Oaks, a newly formed private investment company. Five Oaks is a mortgage real estate investment trust that is focused on investing in, financing and managing a leveraged portfolio of agency and non-agency residential mortgage-backed securities, residential mortgage loans and other mortgage-related investments.
In March 2013, Five Oaks completed an initial public offering (“IPO”) of approximately 4.0 million of its common shares for gross proceeds of approximately $61.0 million and, concurrently with its IPO, Five Oaks sold to the Company an additional 1.67 million shares for $25.0 million in a private placement. Following these transactions, and the receipt of 8,175 shares distributed to the Company in respect of its investment in Oak Circle Capital Partners LLC (“Oak Circle”), the Company's ownership interest in Five Oaks was reduced to 43.8%, which no longer represented a controlling financial interest. Accordingly, the Five Oaks investment was deconsolidated by the Company at the closing date of the Five Oaks IPO. The investment is accounted for under the equity method and carried as a strategic operating affiliate at December 31, 2014. The Company generally records the income related to strategic operating affiliates on a three-month lag based upon the availability of the information provided by the investees. A loss of $1.5 million was recorded upon deconsolidation within Realized investment gains (losses) based upon the difference between the fair value of the Company's retained interest in Five Oaks subsequent to the additional share sales and the Company's carrying value of Five Oaks' net assets at the closing date of the Five Oaks IPO. In addition, in September 2012, the Company received warrants that were priced at the time of the IPO. The warrants allow the Company to purchase an additional 3.125 million shares at $15.75 per share, which would result in a total additional investment of $49.2 million by the Company should it exercise the warrants in full in the future. The warrants expire in September 2019.
As a result of various public offerings which occurred during 2014, the Company's ownership interest in Five Oaks declined to 21.9% at December 31, 2014.
In March 2012, the Company purchased an equity interest in Oak Circle, the investment management company that provides portfolio management and other administrative services to Five Oaks. The Company's investment in Oak Circle is included in investment manager affiliates.
During 2013, the Company purchased an interest in one additional strategic operating affiliate for $30.0 million.
Investment Manager Affiliates
During the years ended December 31, 2014, 2013 and 2012, the Company’s larger investment manager affiliates included Highfields Capital, a global equity investment firm, Polar Capital, an investment firm offering traditional and alternative products, and HighVista Strategies, a diversified wealth management firm.

Other_Investments

Other Investments	12 Months Ended
	Dec. 31, 2014
Investments, All Other Investments [Abstract]
Other investments	Other Investments
	Contained within this asset class are equity interests in alternative and private investment funds, limited partnerships and unrated tranches of collateralized debt obligations for which the Company does not have sufficient rights or ownership interests to use the equity method of accounting. The Company accounts for such equity securities at estimated fair value with changes in fair value recorded through AOCI since it does not have significant influence over these entities. Also included within other investments are structured transactions that are carried at amortized cost.
	Other investments comprised the following at December 31, 2014 and 2013:


	Year ended December 31,	2014		2013
	(U.S. dollars in thousands)
	Alternative Investment Funds:
	Arbitrage	$	179,821	$	158,220

	Directional	336,082		357,469

	Event Driven	56,238		56,873

	Multi-Style	68,706		72,625

	Total alternative funds	$	640,847	$	645,187

	Private investment funds	129,243		94,064

	Overseas deposits	92,223		111,302

	Structured transactions	350,563		294,048

	Other	35,563		20,029

	Total other investments	$	1,248,439	$	1,164,630

	(a) Alternative and Private Investment Funds
	At December 31, 2014 and 2013, the alternative fund portfolio, accounted for as other investments, employed four strategies and invested in 16 alternative funds. The Company is able to redeem the alternative funds on the same terms that the underlying funds can be redeemed. In general, the funds in which the Company is invested require at least 30 days notice of redemption, and may be redeemed on a monthly, quarterly, semi-annual, annual or longer basis, depending on the fund.
	Certain funds have a lock-up period and/or may also have the ability to impose a redemption gate. A lock-up period refers to the initial amount of time an investor is contractually required to remain invested before having the ability to redeem. Typically, the imposition of a gate delays a portion of the requested redemption, with the remaining portion settled in cash shortly after the redemption date.
	The fair value of the Company’s holdings in funds that may be subject to lockups and/or that have gate provisions in their governing documents at December 31, 2014 and 2013 was $425.7 million and $360.6 million, respectively. The Company did not have any holdings in funds where a gate was imposed at December 31, 2014 or 2013.
	Certain funds may be allowed to invest a portion of their assets in illiquid securities, such as private equity or private debt. In such cases, a common mechanism used is a side-pocket, whereby the illiquid security is assigned to a separate memorandum capital account or other designated account. Typically, the investor loses its redemption rights in the designated account. Only when the illiquid securities in the side-pocket are sold, or otherwise deemed liquid by the fund, may investors redeem that portion of their interest that has been “side-pocketed”. At December 31, 2014 and 2013, the fair value of our funds held in side-pockets was $24.5 million and $24.1 million, respectively. The underlying assets within these positions are generally expected to be liquidated over a period of approximately two to four years.
	An increase in market volatility and an increase in the volatility of hedge funds in general, as well as a decrease in market liquidity, could lead to a higher risk of a large decline in the value of the hedge funds in any given time period.
	The following represents an analysis of the net realized gains for the indicated years ended December 31, and the net unrealized gains as of December 31, on the Company’s alternative investment funds and private equity funds:


	Year ended December 31,	Net Unrealized Gains				Net Realized Gains (Losses)
	(U.S. dollars in thousands)	(Losses)
		2014		2013		2014		2013		2012
	Alternative investment funds	$	188,674	$	158,825	$	6,685	$	30,858	$	(2,153	)

	Private investment funds	42,604		44,027		13,275		4,331		257

	Total	$	231,278	$	202,852	$	19,960	$	35,189	$	(1,896	)

	(b) Overseas Deposits
	Overseas deposits include investments in private funds related to Lloyd’s syndicates in which the underlying instruments are primarily government and government-related/supported and corporate fixed income securities. The funds themselves do not trade on an exchange and therefore are not included within available for sale securities. Also included in overseas deposits are restricted cash and cash equivalent balances held by Lloyd’s syndicates for solvency purposes. Given the restricted nature of these cash balances, they are not included within the cash and cash equivalents category in the balance sheets.
	(c) Structured Transactions
	Project Finance Loans
	The Company historically participated in structured transactions in project finance related areas under which the Company provided a cash loan supporting project finance transactions. These transactions are accounted for in accordance with guidance governing accounting by certain entities (including entities with trade receivables) that lend to or finance the activities of others under which the loans are considered held for investment as the Company has the intent and ability to hold for the foreseeable future or until maturity or payoff. Accordingly, these funded loan participations are reported in the balance sheets at outstanding principal adjusted for any allowance for loan losses as considered necessary by management.
	At December 31, 2014 and 2013, the remaining structured project finance loans had an aggregate outstanding principal of $0.4 million and $15.2 million and an aggregate carrying value of nil and $11.1 million, respectively.
	National Indemnity Endorsement
	On June 9, 2009, XL Specialty Insurance Company (“XL Specialty”), a wholly-owned subsidiary of the Company, entered into an agreement with National Indemnity Company, an insurance company subsidiary of Berkshire Hathaway Inc. (“National Indemnity”). Under the agreement, and a related reinsurance agreement, National Indemnity would issue endorsements to certain directors and officers liability insurance policies known as “Side A” coverage policies underwritten by XL Specialty (the “Facility”) during an eighteen month period that ended in December 31, 2011.
	In connection with the Facility, XLIB purchased a payment obligation (the “Obligation”) in an aggregate principal amount of $150.0 million from National Indemnity. The outstanding Obligation was recorded in Other Investments at an estimated fair value of $128.1 million, pays a coupon of 3.5%, and is being accreted to $150.0 million over the 11.5 year term of the payment obligation. The difference between the estimated fair value of the Obligation and the cost of that Obligation at the time of the transaction was approximately $21.9 million and was recorded in Other Assets. This difference, together with fees of $2.5 million, was amortized in relation to the earning of the underlying policies written.
	Other Structured Transactions
	On July 17, 2009, XLIB, a wholly-owned subsidiary of the Company, purchased notes with an aggregate face amount of $155.0 million. The carrying value of these notes at December 31, 2014 and 2013 was $136.0 million and $148.0 million, respectively. The issuer of the notes is a structured credit vehicle that holds corporate debt and preferred equity securities, including some securities issued by European financial institutions, as well as project finance debt securities, among other assets. The notes, which are callable under certain criteria, have a final maturity of July 22, 2039. During the second quarter of 2014, the Company recorded losses of $12.5 million, due to other than temporary declines in value of this other investment.
	On October 29, 2014, XLIB, a wholly-owned subsidiary of the Company, purchased notes with an aggregate face amount of $81.9 million. The carrying value of these notes at December 31, 2014 was $77.8 million. The issuer of the notes is a structured credit vehicle that holds corporate debt and preferred equity securities, including some securities issued by European financial institutions, as well as project finance debt securities, among other assets. The notes, which are callable under certain criteria, have a final maturity of November 3, 2039.
	These structured transactions are not required to be measured at fair value under GAAP and, accordingly, they have been excluded from the fair value measurement disclosures. See Note 4, “Fair Value Measurements,” for details surrounding the estimated fair value of these investments.
	See Note 19(b), “Commitments and Contingencies – Other Investments,” for further information regarding commitments related to other investments.

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and other intangible assets	Goodwill and Other Intangible Assets
	The following table presents an analysis of intangible assets broken down between goodwill, intangible assets with an indefinite life and intangible assets with a definite life for the years ended December 31, 2014, 2013 and 2012:


	(U.S. dollars in thousands)	Goodwill			Intangible		Intangible			Total
					assets with an		assets with a
					indefinite life		definite life
	Balance at December 31, 2011	$	391,498		$	15,366	$	457		$	407,321

	Amortization	—			—		(178		)	(178		)

	Foreign Currency Translation	1,384			—		—			1,384

	Balance at December 31, 2012	$	392,882		$	15,366	$	279		$	408,527

	Amortization	—			—		(279		)	(279		)

	Foreign Currency Translation	3,363			—		—			3,363

	Balance at December 31, 2013	$	396,245		$	15,366	$	—		$	411,611

	Additions	25,159			—		18,500			43,659

	Amortization	—			—		(1,850		)	(1,850		)

	Foreign Currency Translation	(5,468		)	—		—			(5,468		)

	Balance at December 31, 2014	$	415,936		$	15,366	$	16,650		$	447,952

	At December 31, 2014 and 2013, the Company had goodwill of $415.9 million and $396.2 million, respectively, related to the Reinsurance segment. During the first quarter of 2014, Goodwill and Other Intangible Assets increased as a result of the completion of an acquisition. The transaction was accounted for using the acquisition method under which the Company recorded the identifiable assets and liabilities at their acquisition date fair values, and recorded the excess of consideration transferred over the net assets acquired as goodwill and intangible assets. The fair value of identifiable assets and liabilities acquired, as well as amounts recorded in the Company’s consolidated results since the acquisition date, are not material.
	The estimated fair values of the Reinsurance Segment reporting units’ carried goodwill exceeded their estimated net book values at December 31, 2014, and therefore no impairments were recorded during 2014. At December 31, 2014 and 2013, the ending goodwill balance is comprised of gross goodwill of $1.8 billion, offset by accumulated impairment charges of $1.4 billion.
	The Company tests goodwill for impairment on an annual basis, as of June 30, during the third quarter, and on an interim basis when certain events or circumstances exist. The Company tests for impairment at the reporting unit level in accordance with the authoritative guidance on intangibles and goodwill. For the Reinsurance segment, in which all the Company's goodwill resides, a reporting unit is one level below the business segment, while for Insurance, the segment traditionally was also the reporting unit. The first step is to identify potential impairment by comparing the estimated fair value of a reporting unit to its estimated book value, including goodwill. The fair value of each reporting unit is derived based upon valuation techniques and assumptions the Company believes market participants would use to value the business. The Company then compares this estimated fair value to the book value of the reporting units, which it derives by estimating the amount of shareholders’ equity required to support the activities of each reporting unit. The estimated fair values of the reporting units are generally determined utilizing methodologies that incorporate price-to-net-tangible-book and price-to-earnings multiples of certain comparable companies in the industry, from an operational and economic standpoint. If such individual reporting unit estimated fair values - combined with an estimate of an appropriate control premium - exceed their related individual reporting unit net book values, goodwill for those individual reporting units is not deemed to be impaired. A control premium represents the value an investor would pay above non-controlling interest transaction prices in order to obtain a controlling interest in the respective company.
	However, if the margin calculated between the estimated reporting unit fair value and its net book value indicates a potential impairment or a “close call”, a further analysis of the reporting unit’s estimated fair value is performed, using an entity-specific discounted cash flow methodology. This methodology establishes fair value by estimating the present value of the projected future cash flows to be generated from the reporting unit. The discount rate applied to the projected future cash flows to arrive at the present value is intended to reflect all risks of ownership and the associated risks of realizing the stream of projected future cash flows. The discounted cash flow methodology uses the Company’s projections of financial performance for a ten-year period combined with an estimated terminal value. The most significant assumptions used in the discounted cash flow methodology are the discount rate, the terminal value and expected future revenues, gross margins and operating margins, which vary among reporting units. If the individual reporting units' net book values exceed their related individual reporting unit estimated fair values based on this additional methodology, the second step of the goodwill impairment testing process is performed to measure the amount of impairment.

Reinsurance

Reinsurance	12 Months Ended
Reinsurance	Dec. 31, 2014
Reinsurance Disclosures [Abstract]
Reinsurance	Reinsurance
	The Company utilizes reinsurance and retrocession agreements principally to increase aggregate capacity and to reduce the risk of loss on business assumed. The Company’s reinsurance and retrocession agreements provide for recovery of a portion of losses and loss expenses from reinsurers, and reinsurance recoverables are recorded as assets. The Company is liable if the reinsurers are unable to satisfy their obligations under the agreements. Under its reinsurance security policy, the Company seeks to cede business to reinsurers generally with a financial strength rating of “A” or better. The Company considers reinsurers that are not rated or do not fall within the above rating categories and may grant exceptions to the Company’s general policy on a case-by-case basis. The effect of reinsurance and retrocessional activity on premiums written and earned from property and casualty operations is shown below:


	(U.S. dollars in thousands)	Premiums Written										Premiums Earned
		Year Ended December 31,										Year Ended December 31,
		2014				2013			2012			2014			2013			2012
	Direct	$	5,450,868			$	5,050,953		$	4,733,516		$	5,173,403		$	4,966,207		$	4,604,323
	Direct	$	5,450,868			$	5,050,953		$	4,733,516		$	5,173,403		$	4,966,207		$	4,604,323
	Assumed	2,310,621				2,365,839			2,441,612			2,343,329			2,363,261			2,393,490
	Assumed	2,310,621				2,365,839			2,441,612			2,343,329			2,363,261			2,393,490
	Ceded	(1,994,280		)		(1,512,810		)	(1,218,109		)	(1,799,294		)	(1,315,369		)	(1,231,835		)
	Net	$	5,767,209			$	5,903,982		$	5,957,019		$	5,717,438		$	6,014,099		$	5,765,978
	Net	$	5,767,209			$	5,903,982		$	5,957,019		$	5,717,438		$	6,014,099		$	5,765,978
	The Company recorded reinsurance recoveries on losses and loss expenses incurred of $0.7 billion, $0.7 billion and $0.6 billion for the years ended December 31, 2014, 2013 and 2012, respectively.
	The following table presents an analysis of total unpaid losses and loss expenses and future policy benefit reserves recoverable for the year ended December 31:


	(U.S. dollars in thousands)	2014				2013
	P&C Operations	$	3,411,526			$	3,414,735
	P&C Operations	$	3,411,526			$	3,414,735
	Corporate and Other	17,842				20,495
	Corporate and Other	17,842				20,495
	Total unpaid losses and loss expenses recoverable	$	3,429,368			$	3,435,230
	Total unpaid losses and loss expenses recoverable	$	3,429,368			$	3,435,230
	At December 31, 2014 and 2013, the total reinsurance assets of $3.6 billion and $3.6 billion, respectively, included reinsurance receivables for paid losses and loss expenses of $131.5 million and $118.9 million, respectively, with $3.4 billion and $3.4 billion relating to the ceded reserve for losses and loss expenses, including ceded losses incurred but not reported for each year end. Although the contractual obligation of individual reinsurers to pay their reinsurance obligations is based on specific contract provisions, the collectibility of such amounts requires significant estimation by management. The majority of the balance the Company has accrued as recoverable will not be due for collection until sometime in the future. Over this period of time, economic conditions and operational performance of a particular reinsurer may impact its ability to meet these obligations and, while it may continue to acknowledge its contractual obligation to do so, it may not have the financial resources or willingness to fully meet its obligations to the Company.
	At December 31, 2014 and 2013, the allowance for uncollectible reinsurance relating to both reinsurance balances receivable and unpaid losses and loss expenses recoverable was $64.4 million and $85.5 million, respectively. To estimate the provision for uncollectible reinsurance recoverable, the reinsurance recoverable must first be allocated to applicable reinsurers. As part of this process, ceded IBNR is allocated by reinsurer. The allocations are generally based on historical relationships between gross and ceded losses. If actual experience varies materially from historical experience, the allocation of reinsurance recoverable by reinsurer will change.
	The Company uses a default analysis to estimate uncollectible reinsurance recoverables. The primary components of the default analysis are reinsurance recoverable balances by reinsurer, net of collateral, and default factors used to determine the portion of a reinsurer’s balance deemed uncollectible. The definition of collateral for this purpose requires some judgment and is generally limited to assets held in trust, letters of credit, and liabilities held by the Company with the same legal entity for which the Company believes there is a right of offset. The Company is the beneficiary of letters of credit, trust accounts and funds withheld in the aggregate amount of $2.0 billion and $1.8 billion at December 31, 2014 and 2013, respectively, collateralizing reinsurance recoverables with respect to certain reinsurers.
	Default factors require considerable judgment and are determined using the current financial strength rating, or rating equivalent, of each reinsurer as well as other key considerations and assumptions. The total allowance recorded relating to reinsurance recoverables was $42.3 million and $41.4 million at December 31, 2014 and 2013, respectively.
	The Company uses an aging analysis to estimate uncollectible reinsurance balances receivable relating to paid losses in addition to recording allowances relating to any specific balances with known collectibility issues, irrespective of aging. The balances are aged from the date the expected recovery was billed to the reinsurer. Provisions are applied at specified percentages of the outstanding balances based upon the aging profile. Allowances otherwise required as a result of the aging process may not be recorded to the extent that specific facts and circumstances exist that lead management to believe that amounts will ultimately be collectible. The total allowance recorded relating to reinsurance balances receivable was $22.1 million and $44.2 million at December 31, 2014 and 2013, respectively.
	At December 31, 2014, the use of different assumptions within the model could have a material effect on the bad debt provision reflected in the Company’s Consolidated Financial Statements. To the extent the creditworthiness of the Company’s reinsurers was to deteriorate due to an adverse event affecting the reinsurance industry, such as a large number of major catastrophes, actual uncollectible amounts could be significantly greater than the Company’s bad debt provision. Such an event could have a material adverse effect on the Company’s financial condition, results of operations, and cash flows.
	At December 31, 2014 and 2013, approximately 93% and 90%, respectively, of the total unpaid loss and loss expense recoverable and reinsurance balances receivable, net of collateral held, outstanding was due from reinsurers with a financial strength rating of “A” or better. The following is an analysis of the total recoverable and reinsurance balances receivable, net of collateral held, at December 31, 2014, by reinsurers owing 3% or more of such total:


	Name of Reinsurer	Reinsurer Financial Strength Rating		% of Total
	Munich Reinsurance Co.	AA-/Stable		10.5	%
	Swiss Reinsurance Co.	AA-/Stable		8.8	%
	Transatlantic Reinsurance Co.	A+/Stable		8.1	%
	Swiss Re Europe S.A.	AA-/Stable		7.7	%
	Arch Reinsurance Co.	A+/Stable		6.3	%
	Lloyd's Syndicates	A+/Stable		5.1	%
	AXIS Reinsurance Co.	A+/Stable		4.6	%
	The following table sets forth the ratings profile of the reinsurers that support the unpaid loss and loss expense recoverable and reinsurance balances receivable, net of collateral, at December 31, 2014:


	Reinsurer Financial Strength Rating	% of Total
	AAA	0.1	%
	AA	42	%
	A	50.4	%
	BBB	0.4	%
	Captives	5.4	%
	Other	1.7	%
	Total	100	%
	In addition, under the terms of the transaction as described in Note 3, "Sale of Life Reinsurance Subsidiary," the Company has reinsured $4.3 billion of its future policy benefit reserves. Based upon the contractual right of offset, future policy benefit reserves recoverable are netted against the funds withheld liability owing to GCLR. See Note 14, “Funds Withheld on Life Retrocession Arrangements,” for further information.

Losses_and_Loss_Expenses

Losses and Loss Expenses	12 Months Ended
	Dec. 31, 2014
Liability for Claims and Claims Adjustment Expense [Abstract]
Losses and loss expenses	Losses and Loss Expenses
	Unpaid losses and loss expenses for the indicated years ended December 31 are comprised of:


	(U.S. dollars in thousands)	2014				2013
	Reserve for reported losses and loss expenses	$	7,461,444			$	8,149,501

	Reserve for losses incurred but not reported	11,891,799				12,331,564

	Unpaid losses and loss expenses	$	19,353,243			$	20,481,065

	Net losses and loss expenses incurred for the years indicated are comprised of:


	(U.S. dollars in thousands)	2014				2013				2012
	Loss and loss expenses payments	$	4,499,642			$	4,496,802			$	4,673,998

	Change in unpaid losses and loss expenses	(514,406		)		(71,901		)		(297,660		)
	Change in unpaid losses and loss expenses recoverable	(48,536		)		(24,774		)		279,900

	Paid loss recoveries	(678,307		)		(668,663		)		(890,756		)
	Net losses and loss expenses incurred	$	3,258,393			$	3,731,464			$	3,765,482

	The following table represents an analysis of the Company’s paid and unpaid losses and loss expenses incurred and a reconciliation of the beginning and ending unpaid losses and loss expenses for the years indicated:


	(U.S. dollars in thousands)	2014				2013				2012
	Unpaid losses and loss expenses at the beginning of the year	$	20,481,065			$	20,484,121			$	20,613,901

	Unpaid losses and loss expenses recoverable	3,414,735				3,361,703				3,629,940

	Net unpaid losses and loss expenses at the beginning of the year	$	17,066,330			$	17,122,418			$	16,983,961

	Increase (decrease) in net losses and loss expenses incurred in respect of losses occurring in:
	Current year	3,513,469				4,021,353				4,081,376

	Prior year	(255,076		)		(289,889		)		(315,894		)
	Total net incurred losses and loss expenses	$	3,258,393			$	3,731,464			$	3,765,482

	Exchange rate effects	(561,673		)		40,587				156,217

	Less net losses and loss expenses paid in respect of losses occurring in:
	Current year	381,008				425,254				416,844

	Prior year	3,440,327				3,402,885				3,366,398

	Total net paid losses	$	3,821,335			$	3,828,139			$	3,783,242

	Net unpaid losses and loss expenses at the end of the year	15,941,715				17,066,330				17,122,418

	Unpaid losses and loss expenses recoverable	3,411,528				3,414,735				3,361,703

	Unpaid losses and loss expenses at the end of the year	$	19,353,243			$	20,481,065			$	20,484,121

	(a) Prior year net losses incurred
	The following table presents the net (favorable) adverse prior year loss development of the Company’s loss and loss expense reserves for its property and casualty operations by operating segment for each of the years indicated:


	(U.S. dollars in thousands)	2014				2013				2012
	Insurance segment	$	(99,762	)		$	(102,039	)		$	(140,066	)
	Reinsurance segment	(155,314		)		(187,850		)		(175,828		)
	Total	$	(255,076	)		$	(289,889	)		$	(315,894	)
	The significant developments in prior year loss reserve estimates for each of the years indicated within the Company’s Insurance and Reinsurance segments are discussed below.
	Insurance Segment
The following table summarizes the net (favorable) adverse prior year development by line of business relating to the Insurance segment for the indicated years ended December 31:


(U.S. dollars in thousands)	2014				2013				2012
Property	$	(57,470	)		$	(46,387	)		$	(46,735	)
Casualty	38,413				(21,829		)		(61,630		)

Professional	17,094				75,045				(106,360		)

Specialty	(82,756		)		(140,740		)		(61,755		)
Other	(15,043		)		31,872				136,414

Total	$	(99,762	)		$	(102,039	)		$	(140,066	)
Net favorable prior year development of $99.8 million for the Insurance segment for the year ended December 31, 2014 was attributable to the following:

•	For property lines, net prior year development was $57.5 million favorable driven by better than expected loss experience reported for the non-catastrophe exposures predominantly in the 2013 accident year. It was also driven by a reduction of $21.1 million in prior year catastrophe losses primarily in the 2011 accident year.

•	For casualty lines, net prior year development was $38.4 million unfavorable. This was driven by a strengthening of $34.9 million in the U.S. environmental portfolio, $33.3 million in the Lloyd’s middle market book and $26.4 million in the U.S. primary casualty lines mainly as a result of reflecting the worse than expected loss experience reported across the 2008 to 2013 accident years. These deteriorations were partially offset by releases of $28.1 million in the international primary casualty lines and $28.6 million in the excess casualty book driven by better than expected loss experience reported across the 2002 and prior accident years in the case of the former and in aggregate for the latter.

•	For professional lines, net prior year development was $17.1 million unfavorable predominantly as a result of worse than expected loss experience reported in the core U.S. book that drove a strengthening of $40.9 million. This strengthening was partially offset by release of $21.8 million in the core Bermuda book due mainly to better than expected loss experience reported across the 2010 and prior accident years in aggregate.

•	For specialty lines, net prior year development was $82.8 million favorable driven by a release of $61.9 million in the aerospace book due principally to better than expected loss experience reported across the 2012 and prior accident years. It was also driven by a release of $12.2 million in the discontinued international political risk portfolio arising predominantly from a review of the contracts remaining on risk, the contracts that have expired with no claims notified and the single open claim. In addition, our estimate of prior year catastrophe losses was reduced by $5.6 million related primarily to Hurricane Rita in the marine book.

•	For other lines, net prior year development was $15.0 million favorable driven by better than expected loss experience reported across various discontinued lines in aggregate including the favorable settlement of a 2003 claim.
Net favorable prior year reserve development of $102.0 million for the year ended December 31, 2013 was attributable to releases of $140.7 million in specialty, $46.4 million in property, $21.8 million in casualty, partially offset by a strengthening of $75.0 million in professional and $31.9 million in other. Specialty benefited from releases in aerospace, marine and specie, due primarily to reflecting the better than expected loss experience reported predominantly across the 2005 and later accident years, plus a reduction in the Bermuda discontinued political risk book as a result of a review of the open claims and remaining exposure. Better than expected loss experience reported for non-catastrophe exposures primarily in the 2012 accident year led to a release in property, while casualty benefited from better than expected loss experience in the excess casualty book, partially offset by adverse development in the U.S. environmental book and worse than expected loss experience in the Lloyd's middle market book. Worse than expected loss experience in the core U.S. and international professional books led to a strengthening of reserves in professional, as well as deterioration in the discontinued environmental book impacting casualty and the discontinued surety book in other lines.
Net favorable prior year reserve development of $140.1 million for the Insurance segment for the year ended December 31, 2012 was attributable to releases of $106.4 million in professional, $61.8 million in specialty, $61.6 million in casualty and $46.7 million in property, partially offset by a strengthening of $136.4 million in other. Professional benefited from releases in reserves for clash losses (which cover a number of substantially similar claims against multiple policyholders) totaling $120.8 million, partially offset by worse than expected loss experience reported in the design portfolio. Better than expected loss experience reported for the non-catastrophe exposures in the aerospace, specie, product recall and Lloyd’s discontinued political risk books led to the release in specialty, while property benefited from favorable reported loss activity for both the catastrophe and non-catastrophe exposures. The release in casualty was mainly related to better than expected loss experience reported in both the primary and excess books, partially offset by adverse development in U.S. middle markets. Continued worse than expected loss experience reported in the excess and surplus lines, and adverse development in the programs and discontinued surety books drove the strengthening in other lines.
There is no assurance that conditions and trends that have affected the development of liabilities in the past will continue. Accordingly, it may not be appropriate to extrapolate future redundancies or deficiencies based on the Company’s historical results.
Reinsurance Segment
The following table summarizes the net (favorable) adverse prior year development by line of business relating to the Reinsurance segment for the indicated years ended December 31:


(U.S. dollars in thousands)	2014				2013				2012
Property and other short-tail lines	$	(85,324	)		$	(136,912	)		$	(107,613	)
Casualty and other	(69,990		)		(50,938		)		(68,215		)
Total	$	(155,314	)		$	(187,850	)		$	(175,828	)
Net favorable prior year reserve development for the Reinsurance segment of $155.3 million for the year ended December 31, 2014 was attributable to the following:

•	Net favorable prior year development for the short-tailed lines totaled $85.3 million. Details of the significant components are as follows:

◦	For property catastrophe lines, net prior year development was $12.4 million unfavorable driven primarily by an increase on catastrophe losses in 2010 and 2013 being partially offset by reductions on other events and better than expected development on attritional losses in the Bermuda portfolio.

◦	For property other lines, net prior year development was $63.4 million favorable primarily due to better than expected development on attritional losses.

◦	For marine and aviation lines, net prior year development was $34.4 million favorable comprising of $37.7 million better than expected development on attritional losses mainly in the International portfolio, partially offset by $3.3 million unfavorable development on major catastrophe and large losses.

•	Net favorable prior year development for the long-tailed lines totaled $70.0 million. Details of the significant components are as follows:

◦	For casualty lines, net prior year development was $44.3 million favorable due to better than expected development on attritional losses mainly in Europe and North America portfolios being partially offset by an increase on large claims and worse than expected development on attritional losses in Latin America.

◦	For other lines, net prior year development was $25.7 million favorable comprising of $22.7 million better than expected development on attritional losses mainly in Bermuda and North America and a $3.0 million favorable development on major catastrophe and large losses.
Net favorable prior year reserve development of $187.9 million for the year ended December 31, 2013 was attributable to releases of $136.9 million for the short-tailed lines and $50.9 million for the long-tailed lines. The short-tailed lines benefited from $60.0 million in favorable property catastrophe development, $57.3 million in favorable property other lines releases and $19.6 million in favorable marine and aviation development. The release in long-tailed lines was due to $72.2 million in favorable casualty development partially offset by $21.3 million in unfavorable other lines development.
Net favorable prior year reserve development of $175.8 million for the year ended December 31, 2012 was attributable to releases of $107.6 million for the short-tailed lines and $68.2 million for the long-tailed lines. The short-tailed lines benefited from $16.5 million in favorable property catastrophe development, $49.0 million in favorable property other lines releases and $42.2 million in favorable marine and aviation development. The release in long-tailed lines was due to $60.3 million in favorable casualty development and an additional $7.9 million in favorable other lines development mainly driven by an $8.4 million release on the Structured Indemnity book.
The nature of the Company’s high excess of loss liability and catastrophe business can result in loss events that are both irregular and significant. Similarly, adjustments to reserves for individual years can be irregular and significant. Such adjustments are part of the normal course of business for the Company. There is no assurance that conditions and trends that have affected the development of liabilities in the past will continue. Accordingly, it may not be appropriate to extrapolate future redundancies or deficiencies based on the Company’s historical results.
(b) Loss Reserve Discounting
Except for certain workers’ compensation (including long term disability) liabilities and certain bodily injury liability claims, emanating from U.K. exposures, predominantly from the U.K. motor liability portfolio, the Company does not discount its unpaid losses and loss expenses.
The Company utilizes tabular reserving for workers’ compensation (including long-term disability) unpaid losses that are considered fixed and determinable, and discounts such losses using an interest rate of 5% in 2014 and 2013. The interest rate approximates the average yield to maturity on specific fixed income investments that support these liabilities. The tabular reserving methodology results in applying uniform and consistent criteria for establishing expected future indemnity and medical payments (including an explicit factor for inflation) and the use of mortality tables to determine expected payment periods. The workers' compensation unpaid losses and loss expenses, net of reinsurance, at December 31, 2014 and 2013 on an undiscounted basis were $566.2 million and $609.1 million, respectively. For those claims subject to tabular discounting, the corresponding undiscounted amounts, at December 31, 2014 and 2013, were $515.4 million and $551.6 million, respectively. The tabular discounted unpaid losses and loss expenses were $266.4 million and $274.6 million at December 31, 2014 and 2013, respectively.
The Company records a specific reserve allowance for Periodical Payment Orders (“PPO”) related to bodily injury liability claims. This allowance includes the unpaid losses for claims already settled and notified as PPO at December 31, 2014, as well as the unpaid losses for claims to be settled in the future. The future care element of the unpaid losses was discounted using an interest rate of 1.5% at both December 31, 2014 and 2013. Unpaid losses and loss expenses, net of reinsurance, at December 31, 2014 and 2013 on an undiscounted basis were $249.8 million and $262.0 million, respectively. After discounting the future care element, the unpaid losses and loss expenses were $161.0 million and $165.7 million at December 31, 2014 and 2013, respectively. The decrease in net undiscounted unpaid losses and loss expenses between December 31, 2013 and December 31, 2014 is mainly due to foreign exchange rate movements.
(c) Discontinued Asbestos and Run-Off Environmental Related Claims
The Company’s reserving process includes a continuing evaluation of the potential impact on unpaid liabilities from exposure to discontinued asbestos and run-off environmental claims, including related loss adjustment expenses. Liabilities are established to cover both known and incurred but not reported claims. The Company’s reserving and exposures to environmental liability business currently written within the NAPC and IPC business groups are not included in this note, which only relates to specific discontinued and/or run-off coverages that were not originally written specifically to cover environmental hazards.
The Company’s exposure to discontinued asbestos and run-off environmental claims arises from the following three sources:

-1	Reinsurance contracts written, both on a proportional and excess basis, after 1972. The Company discontinued writing contracts with these exposures in 1985. Business written was across many different policies, each with a relatively small contract limit. The Company’s reported asbestos claims relate to both traditional products and premises and operations coverage.

-2	Winterthur – business of Winterthur purchased by the Company from AXA Insurance (formerly Winterthur Swiss Insurance Company) in 2001. Pursuant to the Sale and Purchase Agreement and related agreements, AXA Insurance reimburses the Company for all asbestos losses.

-3	During 2006, the Company acquired $40.2 million in losses through a loss portfolio transfer contract of which $18.3 million in losses related to asbestos and environmental claims. Given the terms of the policy, the combined aggregate limit on the total acquired reserves is limited to $60.0 million, not including coverage for claims handling costs over a defined period.
A reconciliation of the opening and closing unpaid losses and loss expenses related to discontinued asbestos and run-off environmental exposure claims for the years indicated is as follows:


Year ended December 31,	2014				2013				2012
(U.S. dollars in thousands)
Net unpaid losses and loss expenses at beginning of year	$	80,435			$	78,315			$	77,778

Net incurred losses and loss expenses	8,903				6,257				6,558

Less net paid losses and loss expenses	7,922				4,137				6,021

Net increase (decrease) in unpaid losses and loss expenses	$	981			$	2,120			$	537

Net unpaid losses and loss expenses at end of year	81,416				80,435				78,315

Unpaid losses and loss expenses recoverable at end of year	100,537				115,090				123,799

Gross unpaid losses and loss expenses at end of year	$	181,953			$	195,525			$	202,114

Reserves for incurred but not reported losses, net of reinsurance, included in the above table were $49.3 million, $48.6 million and $52.2 million at December 31, 2014, 2013 and 2012, respectively. Unpaid losses recoverable are net of potential uncollectible amounts.
At December 31, 2014, the Company had 1,399 open claim files for potential discontinued asbestos claims exposures and 459 open claim files for potential run-off environmental claims exposures. Approximately 46%, 37% and 42% of the open claim files are due to precautionary claim notices in 2014, 2013 and 2012, respectively. Precautionary claim notices are submitted by the ceding companies in order to preserve their right to receive coverage under the reinsurance contract. The increase in open claim files during 2014 was largely due to internal changes in how claims reported in previous years were classified, which resulted in a higher number of precautionary claims opened during the year.
Such notices do not contain an incurred loss amount to the Company. The development of the number of open claim files for potential discontinued asbestos and run-off environmental claims, including precautionary claims, is as follows:


	Asbestos			Environmental
	Claims			Claims
Total number of claims outstanding at December 31, 2011	1,038			362

New claims reported in 2012	236			60

Claims resolved in 2012	(201	)		(68	)
Total number of claims outstanding at December 31, 2012	1,073			354

New claims reported in 2013	178			34

Claims resolved in 2013	(154	)		(50	)
Total number of claims outstanding at December 31, 2013	1,097			338

New claims reported in 2014	456			190

Claims resolved in 2014	(154	)		(69	)
Total number of claims outstanding at December 31, 2014	1,399			459

The Company’s reserving process includes a continuing evaluation of the potential impact on unpaid liabilities from exposure to discontinued asbestos and run-off environmental claims, including related loss adjustment expenses. Liabilities are established to cover both known and incurred but not reported claims.
The estimation of loss and loss expense liabilities for discontinued asbestos and run-off environmental exposures is subject to much greater uncertainty than is normally associated with the establishment of liabilities for certain other exposures due to several factors, including: (i) uncertain legal interpretation and application of insurance and reinsurance coverage and liability; (ii) the lack of reliability of available historical claims data as an indicator of future claims development; (iii) an uncertain political climate which may impact, among other areas, the nature and amount of costs for remediating waste sites; and (iv) the potential of insurers and reinsurers to reach agreements in order to avoid further significant legal costs. Due to the potential significance of these uncertainties, the Company believes that no meaningful range of loss and loss expense liabilities beyond recorded reserves can be established. As the Company’s net unpaid loss and loss expense reserves related to discontinued asbestos and run-off environmental exposures are less than 1% of the total net reserves at December 31, 2014 and 2013, further adverse development is not expected to be material to the Company’s overall net loss reserves. The Company believes it has made reasonable provision for its discontinued asbestos and run-off environmental exposures and is unaware of any specific issues that would significantly affect its estimate for loss and loss expenses.

Deposit_Liabilities

Deposit Liabilities	12 Months Ended
Deposit Liabilities	Dec. 31, 2014
Deposit Contract Liabilities [Abstract]
Deposit liabilities	Deposit Liabilities
	The Company has entered into certain insurance and reinsurance policies that transfer insufficient risk under GAAP to be accounted for as insurance or reinsurance transactions and are recognized as deposits. These structured property and casualty agreements have been recorded as deposit liabilities and are initially matched by an equivalent amount of investments. The Company has investment risk related to its ability to generate sufficient investment income to enable the total invested assets to cover the payment of the ultimate liability. See Note 6, “Investments,” for further information relating to the Company’s net investment income as well as realized and unrealized investment (losses) gains. Each deposit liability accrues at a rate equal to the internal rate of return of the payment receipts and obligations due during the life of the agreement. Where the timing and/or amount of future payments are uncertain, cash flows reflecting the Company’s actuarially determined best estimates are utilized. Deposit liabilities are initially recorded at an amount equal to the assets received.
	At December 31, 2014 and 2013, total deposit liabilities were $1.2 billion and $1.5 billion, respectively. For the years ended December 31, 2014, 2013 and 2012, interest expense of $12.9 million, $48.0 million and $66.3 million, respectively, was recorded related to the accretion of deposit liabilities. During the second quarter of 2014, the Company negotiated the termination of one of its larger structured indemnity contracts and as a result a net decrease of $28.7 million was recorded to interest expense. See Note 16, “Derivative Instruments,” for further information.

Future_Policy_Benefit_Reserve

Future Policy Benefit Reserve	12 Months Ended
	Dec. 31, 2014
Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract]
Future policy benefit reserve	Future Policy Benefit Reserves
	Future policy benefit reserves are comprised of the following:


	Year ended December 31	2014		2013
	(U.S. dollars in thousands)
	Traditional Life	$	789,133	$	827,341

	Annuities	3,918,066		3,976,475

	Total future policy benefit reserves	$	4,707,199	$	4,803,816

	The Company entered into long duration contracts that subject the Company to mortality and morbidity risks and that were accounted for as life premiums earned. Future policy benefit reserves were established using appropriate assumptions for investment yields, mortality, and expenses, including a provision for adverse deviation. At December 31, 2014 and 2013, the average interest rate used for the determination of the future policy benefits for these contracts was 3.3% and 4.4%, respectively. Total future policy benefit reserves for the years ended December 31, 2014 and 2013 were $4.7 billion and $4.8 billion, respectively. The net decrease, during 2014, in the total future policy benefit reserves was from normal course releases on single premium annuities in line with the benefits paid and mortality of underlying policyholders, which has been partially offset by foreign exchange movements.
	Under the terms of the transaction described in Note 3, "Sale of Life Reinsurance Subsidiary," the Company has reinsured $4.3 billion of its future policy benefit reserves. Based upon the contractual right of offset, future policy benefit reserves recoverable are netted against the funds withheld liability owing to GCLR. See Note 14, “Funds Withheld on Life Retrocession Arrangements,” for further information.

Funds_Withheld_on_Life_Retroce

Funds Withheld on Life Retrocession Arrangements	12 Months Ended
	Dec. 31, 2014
Funds Withheld on Life Retrocession Arrangements Disclosure [Abstract]
Funds Withheld on Life Retrocession Arrangements [Text Block]	Funds Withheld on Life Retrocession Arrangements
	Under the terms of the transaction as described in Note 3, "Sale of Life Reinsurance Subsidiary," the Company continues to own, on a funds withheld basis, assets supporting the Life Retro Arrangements consisting of cash, fixed maturity securities and accrued interest. Based upon the contractual right of offset, the funds withheld liability owing to GCLR is recorded net of future policy benefit reserves recoverable, and is included within “Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable)" on the consolidated balance sheets.
	Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable) for the year ended December 31, 2014 are comprised of:


	(U.S. dollars in thousands)	2014
	Assets held on a funds withheld basis relating to the Life Retro Arrangements	$	5,420,694

	Reinsurance recoverable from GCLR	(4,265,678		)
	Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable)	$	1,155,016

Notes_Payable_and_Debt_and_Fin

Notes Payable and Debt and Financing Arrangements	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Notes payable and debt and financing arrangements	Notes Payable and Debt and Financing Arrangements
	At December 31, the Company’s financing structure, which includes senior unsecured notes, bank and loan facilities available from a variety of sources, including commercial banks, and letter of credit facilities was as follows:


	(U.S. dollars in thousands)	2014						2013
		Commitment/			In Use/			Commitment/		In Use/
		Debt			Outstanding (1)			Debt		Outstanding (1)
	Debt:
	5-year revolver expiring 2018	$	1,000,000		$	—		$	1,000,000	$	—

	5.25% Senior Notes due 2014	—			—			600,000		599,346

	2.30% Senior Notes due 2018	300,000			297,344			300,000		296,683

	5.75% Senior Notes due 2021	400,000			397,092			400,000		396,661

	6.375% Senior Notes due 2024	350,000			348,920			350,000		348,811

	6.25% Senior Notes due 2027	325,000			323,062			325,000		322,905

	5.25% Senior Notes due 2043	300,000			296,162			300,000		296,030

	Total debt	$	2,675,000		$	1,662,580		$	3,275,000	$	2,260,436

	Adjustment to carrying value – impact of fair value hedges				—					2,767

	Total debt carrying value	$	2,675,000		$	1,662,580		$	3,275,000	$	2,263,203

	Letters of Credit:
	Total letters of credit	$	3,575,000		$	1,790,561		$	3,575,000	$	1,895,425


	____________

	-1	“In Use” and “Outstanding” data represent December 31, 2014 and 2013 accreted values.
	(a) Notes Payable and Debt
	All outstanding debt of the Company at December 31, 2014 and 2013, which is identified in the table above, was issued by XL-Cayman, a 100% owned subsidiary of XL-Ireland and the only direct subsidiary thereof. XL-Ireland does not have significant assets or operations independent of XL-Cayman. XL-Cayman's outstanding debt is fully and unconditionally guaranteed by XL-Ireland. The ability of XL-Cayman, like that of the Company, to obtain funds from its subsidiaries to satisfy any of its obligations is subject to certain contractual restrictions, applicable laws and statutory requirements of the various countries in which the Company operates, including, among others, Bermuda, the United States, Ireland, Switzerland and the United Kingdom. For details of the required statutory capital and surplus for the principal operating subsidiaries of the Company, see Note 25, “Statutory Financial Data.”
	On September 15, 2014, the $600 million principal amount outstanding on the 5.25% Senior Notes issued by XL-Cayman was repaid at maturity.
	The Company was in compliance with all covenants by significant margins at December 31, 2014 and 2013, and the Company currently remains in compliance with all covenants.
	(b) Letter of Credit Facilities and Other Sources of Collateral
	The Company has several letter of credit facilities provided on both syndicated and bilateral bases from commercial banks. These facilities are utilized primarily to support non-admitted insurance and reinsurance operations in the U.S. and capital requirements at Lloyd’s. The Company’s letter of credit facilities and revolving credit facilities at December 31 were as follows:


	(U.S. dollars in thousands)	2014 (1)			2013 (1)
	Revolving credit facility (2)	$	1,000,000		$	1,000,000

	Available letter of credit facilities – commitments (3)	$	3,575,000		$	3,575,000

	Available letter of credit facilities – in use	$	1,790,561		$	1,895,425

	Collateralized by certain assets of the Company’s investment portfolio	66.2		%	67.6		%

	____________

	-1	At December 31, 2014, there were eight available letter of credit facilities; at December 31, 2013, there were seven available letter of credit facilities.

	-2	At December 31, 2014 and 2013, the revolving credit available under the Syndicated Credit Agreements (as defined below) and under the December 9, 2011 unsecured credit agreement, respectively, was unutilized. The 2013 Citi Agreements (as defined below) provide for issuance of letters of credit and revolving credit loans in an aggregate amount of up to $575 million. At December 31, 2014, $575 million of letters of credit were issued under the 2013 Citi Agreements and therefore such amount is not included here.

	-3	The Company has the option to increase the size of the facilities under the Syndicated Credit Agreements by an additional $500 million across such facilities. The Company also has the option to increase the maximum amount of the letters of credit and revolving credit loans available under the 2013 Citi Agreements, with the lender's and issuing lender's consent.
	In November 2013, the Company (i) entered into two new credit agreements (together, the "Syndicated Credit Agreements"), which provided for an aggregate amount of outstanding letters of credit and revolving credit loans of up to $2 billion, subject to certain options to increase the size of the facilities, and (ii) terminated the secured credit agreements dated March 25, 2011 and December 9, 2011, and the unsecured credit agreement dated December 9, 2011, which had provided for an aggregate amount of outstanding letters of credit and revolving credit loans of up to $3 billion.
	The Syndicated Credit Agreements consist of (i) a secured credit agreement, which provides for the issuance of letters of credit in an aggregate amount of up to $1 billion, and (ii) an unsecured credit agreement, which provides for the issuance of letters of credit and revolving credit loans in an aggregate amount of up to $1 billion. The Company has the option to increase the maximum amount of letters of credit available by an additional $500 million across the facilities under the Syndicated Credit Agreements.
	The commitments under the Syndicated Credit Agreements expire on, and such credit facilities are available until, the earlier of (i) November 22, 2018 and (ii) the date of termination in whole of the commitments upon an optional termination or reduction of the commitments by the account parties or upon the occurrence of certain events of default.
	The availability of letters of credit under the secured portion of the Syndicated Credit Agreements is subject to a borrowing base requirement, determined on the basis of specified percentages of the face value of eligible categories of assets varying by type of collateral. In the event that such credit support is insufficient, the Company could be required to provide alternative security to cedants. This could take the form of insurance trusts supported by the investment portfolio or funds withheld (amounts retained by ceding companies to collateralize loss or premium reserves) using the Company's cash resources or combinations thereof. The face amount of letters of credit required is driven by, among other things, loss development of existing reserves, the payment pattern of such reserves, the expansion of business written by the Company and the loss experience of such business.
	On May 7, 2013, XL-Cayman entered into a new credit agreement with Citicorp USA, Inc., as administrative agent and issuing lender, and the lenders party thereto, and a continuing agreement for standby letters of credit with Citibank, N.A. On May 13, 2013 and May 15, 2013, XL-Cayman entered into a first amendment and second amendment, respectively, to such credit agreement (as amended, the “May 2013 Credit Agreement”).
On August 6, 2013, XL-Cayman entered into a new credit agreement with Citicorp USA, Inc., as administrative agent and issuing lender, and the lenders party thereto and a continuing agreement for standby letters of credit with Citibank, N.A. On September 12, 2013, XL-Cayman entered into a first amendment to such credit agreement (as amended, the “August 2013 Credit Agreement”).
Additionally, on November 4, 2013, XL-Cayman entered into a new credit agreement with Citicorp USA, Inc., as administrative agent and issuing lender, and the lenders party thereto and a continuing agreement for standby letters of credit with Citibank, N.A. (the "November 2013 Credit Agreement" and, together with the May 2013 Credit Agreement and the August 2013 Credit Agreement, the "2013 Citi Agreements").
Collectively, the 2013 Citi Agreements and the continuing agreements for standby letters of credit provide for the issuance of letters of credit and revolving credit loans in an aggregate amount of up to $575 million. XL-Cayman has the option to increase the maximum amount of letters of credit and revolving credit loans available under the 2013 Citi Agreements with the lender's and issuing lender's consent.
The commitments under the 2013 Citi Agreements expire on, and such credit facilities are available until, the earlier of (i) June 20, 2015 (with respect to the May 2013 Credit Agreement), September 20, 2015 (with respect to the August 2013 Credit Agreement) and December 20, 2016 (with respect to the November 2013 Credit Agreement) and (ii) the date of termination in whole of the commitments upon an optional termination or reduction of the commitments by the account parties or upon the occurrence of certain events of default.
On December 30, 2014, XLIB reduced the commitments available under a continuous letter of credit facility between XL Insurance (Bermuda) Ltd. and Citibank Europe plc from $750 million to $600 million simultaneous with XL Insurance (Bermuda) Ltd. entering into a continuous $150 million letter of credit facility with ING Bank N.V., London Branch.
In addition to letters of credit, the Company has established insurance trusts in the United States that provide cedants with statutory relief required under state insurance regulation in the United States. It is anticipated that the commercial facilities may be renewed on expiry but such renewals are subject to the availability of credit from banks utilized by the Company and may be renewed with materially different terms and conditions. In the event that such credit support is insufficient, the Company could be required to provide alternative security to cedants. This could take the form of additional insurance trusts supported by the Company’s investment portfolio or funds withheld using the Company’s cash resources. The value of letters of credit required is driven by, among other things, loss development of existing reserves, the payment pattern of such reserves, the expansion of business written by the Company and the loss experience of such business.
In general, all of the Company’s bank facilities, indentures and other documents relating to the Company’s outstanding indebtedness (collectively, the “Company’s Debt Documents”), which are described above, contain cross acceleration or cross default provisions to each other and the Company’s Debt Documents contain affirmative covenants. These covenants provide for, among other things, minimum required ratings of the Company’s insurance and reinsurance operating subsidiaries and a maximum level of secured indebtedness that may be incurred in the future. In addition, generally each of the Company’s Debt Documents provide for an event of default in the event of a change of control of the Company or some events involving bankruptcy, insolvency or reorganization of the Company. The Company’s credit facilities also contain minimum consolidated net worth covenants.
Under the Syndicated Credit Agreements, in the event that XL Insurance (Bermuda) Ltd, XL Re Ltd or XL Re Europe SE fails to maintain a financial strength rating of at least “A – ” from A.M. Best, an event of default would occur.
Given that all of the Company’s Debt Documents contain cross acceleration or cross default provisions, a default by one of these subsidiaries may result in all holders declaring their debt due and payable and accelerating all debt due under those documents. If this were to occur, the Company may not have funds sufficient at that time to repay any or all of such indebtedness.

Derivative_Instruments

Derivative Instruments	12 Months Ended
Derivative Instruments	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative instruments	Derivative Instruments
	The Company enters into derivative instruments for both risk management and investment purposes. The Company is exposed to potential loss from various market risks, and manages its market risks based on guidelines established by management and the Risk and Finance Committee of the Company's Board of Directors. The Company recognizes all derivatives as either assets or liabilities in the balance sheets and measures those instruments at fair value, with the changes in fair value of derivatives shown in the consolidated statement of income as “Net realized and unrealized gains (losses) on derivative instruments” unless the derivatives are designated as hedging instruments. The accounting for derivatives that are designated as hedging instruments is described in Note 2(h), “Significant Accounting Policies – Derivative Instruments.” The following table summarizes information on the location and gross amounts of derivative fair values contained in the consolidated balance sheets at December 31, 2014 and 2013:


	(U.S. dollars in thousands)	2014											2013
		Asset			Asset			Liability			Liability		Asset		Asset		Liability		Liability
		Derivative			Derivative			Derivative			Derivative		Derivative		Derivative		Derivative		Derivative
		Notional			Fair			Notional			Fair		Notional		Fair		Notional		Fair
		Amount			Value (1)			Amount			Value (1)		Amount		Value (1)		Amount		Value (1)
	Derivatives designated as hedging instruments:
	Foreign exchange contracts	$	2,300,609		$	121,862		$	302,211		$	2,936	$	1,005,610	$	26,098	$	2,572,227	$	70,462
	Foreign exchange contracts	$	2,300,609		$	121,862		$	302,211		$	2,936	$	1,005,610	$	26,098	$	2,572,227	$	70,462
	Total derivatives designated as hedging instruments	$	2,300,609		$	121,862		$	302,211		$	2,936	$	1,005,610	$	26,098	$	2,572,227	$	70,462
	Total derivatives designated as hedging instruments	$	2,300,609		$	121,862		$	302,211		$	2,936	$	1,005,610	$	26,098	$	2,572,227	$	70,462
	Derivatives not designated as hedging instruments:
	Investment Related Derivatives:
	Interest rate exposure	$	394,597		$	206		$	20,782		$	51	$	30,702	$	266	$	10,259	$	8
	Interest rate exposure	$	394,597		$	206		$	20,782		$	51	$	30,702	$	266	$	10,259	$	8
	Foreign exchange exposure	7,385			403			288,376			4,724		17,497		12		50,614		680
	Foreign exchange exposure	7,385			403			288,376			4,724		17,497		12		50,614		680
	Credit exposure	2,408			165			14,270			9,836		—		—		340,020		15,128
	Credit exposure	2,408			165			14,270			9,836		—		—		340,020		15,128
	Financial market exposure	46,145			360			33,670			34		58,232		1,111		14,821		77
	Financial market exposure	46,145			360			33,670			34		58,232		1,111		14,821		77
	Financial Operations Derivatives: (2)
	Credit exposure	—			—			—			—		—		—		44,234		4,190
	Credit exposure	—			—			—			—		—		—		44,234		4,190
	Other Non-Investment Derivatives:
	Credit exposure	31,060			60			—			—		—		—		—		—
	Credit exposure	31,060			60			—			—		—		—		—		—
	Guaranteed minimum income benefit contract	46,249			13,603			46,249			13,603		—		—		53,564		14,940
	Guaranteed minimum income benefit contract	46,249			13,603			46,249			13,603		—		—		53,564		14,940
	Modified coinsurance funds withheld contract (3)	64,947			—			5,401,278			—		66,369		—		—		—
	Modified coinsurance funds withheld contract (3)	64,947			—			5,401,278			—		66,369		—		—		—
	Total derivatives not designated as hedging instruments	$	592,791		$	14,797		$	5,804,625		$	28,248	$	172,800	$	1,389	$	513,512	$	35,023
	Total derivatives not designated as hedging instruments	$	592,791		$	14,797		$	5,804,625		$	28,248	$	172,800	$	1,389	$	513,512	$	35,023
	____________

	-1	Derivative instruments in an asset or liability position are included within Other assets or Other liabilities, respectively, in the balance sheets on a net basis where the Company has both a legal right of offset and the intention to settle the contracts on a net basis.

	-2	Financial operations derivatives represent interests in variable interest entities as described in Note 18, “Variable Interest Entities".

	-3	The fair value movements in derivative assets and liabilities relating to modified coinsurance funds withheld contracts are included within the associated asset or liability at each period end on the face of the balance sheets. Notional amounts associated with reinsurance agreements under which the Company assumes reinsurance risk are recorded as asset derivative notional amounts. Notional amounts associated with the Life Retro Arrangements under which the Company cedes reinsurance risk are recorded as liability derivative notional amounts. Included in the liability derivative notional amount at December 31, 2014 is the cumulative net realized and unrealized loss on life retrocession embedded derivative of $450.8 million.
	The following table summarizes information on the gross and net amounts of derivative fair values and associated collateral received related to derivative assets or paid relating to derivative liabilities contained in the consolidated balance sheets at December 31, 2014 and 2013:


											Gross Amounts Not Offset in the Balance Sheets
	31-Dec-14	Gross Amounts Recognized in the Balance Sheets			Gross Amounts Offset in the Balance Sheets			Net Amounts in the Balance Sheets			Financial Instruments		Cash Collateral		Net Amounts
	(U.S. dollars in thousands)	Gross Amounts Recognized in the Balance Sheets			Gross Amounts Offset in the Balance Sheets			Net Amounts in the Balance Sheets			Financial Instruments		Cash Collateral		Net Amounts
	Derivative Assets	$	136,659		$	696		$	135,963		$	—	$	78,580	$	57,383
	Derivative Assets	$	136,659		$	696		$	135,963		$	—	$	78,580	$	57,383
	Derivative Liabilities	$	31,184		$	696		$	30,488		$	—	$	—	$	30,488
	Derivative Liabilities	$	31,184		$	696		$	30,488		$	—	$	—	$	30,488

	31-Dec-13
	(U.S. dollars in thousands)
	Derivative Assets	$	27,487		$	1,342		$	26,145		$	—	$	—	$	26,145
	Derivative Assets	$	27,487		$	1,342		$	26,145		$	—	$	—	$	26,145
	Derivative Liabilities	$	105,485		$	1,342		$	104,143		$	—	$	19,847	$	84,296
	Derivative Liabilities	$	105,485		$	1,342		$	104,143		$	—	$	19,847	$	84,296
	Derivative instruments in an asset or liability position are included within Other assets or Other liabilities, respectively, in the balance sheets on a net basis where the Company has both a legal right of offset and the intentions to settle the contracts on a net basis. The Company often enters into different types of derivative contracts with a single counterparty and these contracts are covered under netting agreements. At December 31, 2014, the Company held cash collateral related to foreign currency derivative positions and certain other derivative positions of $78.6 million. At December 31, 2013, the Company paid cash collateral related to foreign currency derivative positions and certain other derivative positions of $19.8 million. The assets and liability related to the net collateral paid or held were recorded as Other assets and Other liabilities, respectively, within the balance sheets as the collateral and derivative positions are not intended to be settled on a net basis.
	(a) Derivative Instruments Designated as Fair Value Hedges
	The Company designates certain of its derivative instruments as fair value hedges or cash flow hedges and formally and contemporaneously documents all relationships between the hedging instruments and hedged items and links the hedging derivative to specific assets and liabilities. The Company assesses the effectiveness of the hedge both at inception and on an on-going basis, and determines whether the hedge is highly effective in offsetting changes in fair value or cash flows of the linked hedged item.
	The Company may hedge portions of its liabilities against changes in the applicable designated benchmark interest rate. Interest rate swaps may also be used to hedge the changes in fair value of certain fixed rate liabilities and fixed income securities due to changes in the designated benchmark interest rate. In addition, the Company utilizes foreign exchange contracts to hedge the fair value of certain fixed income securities as well as to hedge certain net investments in foreign operations.
The following table provides the total impact on earnings relating to derivative instruments formally designated as fair value hedges along with the impacts of the related hedged items for the years indicated:


Derivatives Designated as Fair Value Hedges	Hedged Items – Amount of Gain/(Loss) Recognized in Income Attributable to Risk
(U.S. dollars in thousands)	Gain/(Loss) Recognized in Income on Derivative			Deposit			Fixed			Ineffective Portion of Hedging Relationship – Gain/(Loss)
				Liabilities			Maturity
							Investments
Year Ended December 31, 2014
Interest rate exposure	$	—
Interest rate exposure	$	—
Foreign exchange exposure	(15,663		)
Total	$	(15,663	)	$	—		$	15,407		$	(256	)
Total	$	(15,663	)	$	—		$	15,407		$	(256	)
Year Ended December 31, 2013
Interest rate exposure	$	—
Interest rate exposure	$	—
Foreign exchange exposure	(22,568		)
Total	$	(22,568	)	$	—		$	23,065		$	497
Total	$	(22,568	)	$	—		$	23,065		$	497
Year Ended December 31, 2012
Interest rate exposure	$	1,813
Interest rate exposure	$	1,813
Foreign exchange exposure	(24,183		)
Total	$	(22,370	)	$	(6,182	)	$	23,967		$	(4,585	)
Total	$	(22,370	)	$	(6,182	)	$	23,967		$	(4,585	)
The gains (losses) recorded on both the derivative instruments and specific items designated as being hedged as part of the fair value hedging relationships outlined above along with any associated ineffectiveness in the relationships are recorded through Net realized and unrealized gains (losses) on derivative instruments in the income statement. In addition, the periodic coupon settlements relating to the interest rate swaps are recorded as adjustments to net investment income for the hedges of fixed maturity investments.
The periodic coupon settlements also resulted in decreases to Interest expense of nil, nil and $4.9 million for the years ended December 31, 2014, 2013 and 2012, respectively.
Settlement of Fair Value Hedges
A summary of the fair value hedges that have been settled and their impact on results during the indicated years ended December 31 as well as the remaining balance of fair value hedges and average years remaining to maturity are shown below:


Settlement of Fair Value Hedges – Summary	Fair Value Hedges –						Fair Value Hedges –
(U.S. dollars in thousands, except years)	Notes Payable and Debt						Deposit Liabilities
	December 31,						December 31,
	2014			2013			2014			2013
Cumulative reduction to interest expense	$	21,624		$	18,856		$	95,333		$	37,382
Cumulative reduction to interest expense	$	21,624		$	18,856		$	95,333		$	37,382
Remaining balance	$	—		$	2,767		$	137,862		$	195,814
Remaining balance	$	—		$	2,767		$	137,862		$	195,814
Weighted average years remaining to maturity	0			0.7			23.2			22.7
Weighted average years remaining to maturity	0			0.7			23.2			22.7

During the second quarter of 2014, the Company negotiated the termination of one of its larger structured indemnity contracts. This contract had previously been designated as a fair value hedge that was settled. The remaining fair value adjustment of $47.0 million that was being amortized as a reduction of interest expense over the remaining term of the contract was recorded as an adjustment to interest expense at the termination date. As a result of the termination, a net decrease of $28.7 million was recorded to interest expense reflecting the realization of the remaining balance of the fair value hedge adjustment, partially offset by an accretion rate adjustment due to changes in cash flows.
(b) Derivative Instruments Designated as Hedges of the Net Investment in a Foreign Operation
The Company utilizes foreign exchange contracts to hedge the fair value of certain net investments in foreign operations. During the year ended December 31, 2014 and 2013, the Company entered into foreign exchange contracts that were formally designated as hedges of investments in foreign subsidiaries, the majority of which have functional currencies of either U.K. sterling or the Euro. There was no ineffectiveness in these transactions.
The following table provides the weighted average U.S. dollar equivalent of foreign denominated net assets that were hedged and the resulting derivative gain (loss) that was recorded in the foreign currency translation adjustment, net of tax, account within AOCI for the year ended December 31, 2014 and 2013.


Derivative Instruments Designated as Hedges of the Net Investment in a Foreign Operation – Summary	2014			2013
(U.S. dollars in thousands)	2014			2013
Weighted average of U.S. dollar equivalent of foreign denominated net assets	$	2,384,508		$	2,648,137
	$	2,384,508		$	2,648,137
Derivative gains (losses) (1)	$	120,643		$	(27,392	)
Derivative gains (losses) (1)	$	120,643		$	(27,392	)

____________

-1	Derivative gains (losses) from derivative instruments designated as hedges of the net investment in a foreign operation are recorded in the cumulative translation adjustment account within AOCI for each period.
(c) Derivative Instruments Not Formally Designated As Hedging Instruments
The following table provides the total impact on earnings relating to derivative instruments not formally designated as hedging instruments under authoritative accounting guidance and from the ineffective portion of fair value hedges. The impacts are all recorded through Net realized and unrealized gains (losses) on derivatives in the income statement for the years ended December 31, 2014, 2013 and 2012:


Net Realized and Unrealized Gains (Losses) on Derivative Instruments	2014			2013			2012
(U.S. dollars in thousands)	2014			2013			2012
Investment Related Derivatives:
Interest rate exposure	$	15,959		$	5,065		$	4,394
Interest rate exposure	$	15,959		$	5,065		$	4,394
Foreign exchange exposure	3,351			(948		)	(1,084		)
Foreign exchange exposure	3,351			(948		)	(1,084		)
Credit exposure	400			(4,052		)	(7,611		)
Credit exposure	400			(4,052		)	(7,611		)
Financial market exposure	411			6,302			3,073
Financial market exposure	411			6,302			3,073
Financial Operations Derivatives:
Credit exposure	5,023			(2,437		)	10,511
Credit exposure	5,023			(2,437		)	10,511
Other Non-Investment Derivatives:
Credit exposure	—			—			—
Credit exposure	—			—			—
Guaranteed minimum income benefit contract	2,257			10,457			(2,906		)
Guaranteed minimum income benefit contract	2,257			10,457			(2,906		)
Modified coinsurance funds withheld contract	2,741			(7,086		)	3,429
Modified coinsurance funds withheld contract	2,741			(7,086		)	3,429
Total derivatives not designated as hedging instruments	$	30,142		$	7,301		$	9,806
Total derivatives not designated as hedging instruments	$	30,142		$	7,301		$	9,806
Amount of gain (loss) recognized in income from ineffective portion of fair value hedges	(256		)	497			(4,585		)
	(256		)	497			(4,585		)
Net realized and unrealized gains (losses) on derivative instruments	$	29,886		$	7,798		$	5,221
	$	29,886		$	7,798		$	5,221
Net realized and unrealized gains (losses on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets	$	(488,222	)	$	—		$	—
	$	(488,222	)	$	—		$	—
The Company’s objectives in using these derivatives are explained below.
(d)(i) Investment Related Derivatives
The Company, either directly or through its investment managers, may use derivative instruments within its investment portfolio, including interest rate swaps, inflation swaps, commodity contracts, credit derivatives (single name and index credit default swaps), options, forward contracts and financial futures (foreign exchange, bond and stock index futures), primarily as a means of economically hedging exposures to interest rate, credit spread, equity price changes and foreign currency risk or, in limited instances, for investment purposes. When using cleared (exchange traded) derivatives, the Company is exposed to the credit risk of the applicable clearing house and of the Company's future commissions merchant. When using uncleared (over-the-counter) derivatives, the Company is exposed to credit risk in the event of non-performance by the counterparties under any derivative contracts, although the Company generally seeks to use credit support arrangements with counterparties to help manage this risk.
Investment Related Derivatives – Interest Rate Exposure
The Company utilizes risk management and overlay strategies that incorporate the use of derivative financial instruments, primarily to manage its fixed income portfolio duration and net economic exposure to interest rate risks. The Company may also use interest rate swaps to convert certain liabilities from a fixed rate to a variable rate of interest or use them to convert a variable rate of interest from one basis to another.
Investment Related Derivatives – Foreign Exchange Exposure
The Company has exposure to foreign currency exchange rate fluctuations through its operations and in its investment portfolio. The Company uses foreign exchange contracts to manage its exposure to the effects of fluctuating foreign currencies on the value of certain of its foreign currency fixed maturities. These contracts are not designated as specific hedges for financial reporting purposes and, therefore, realized and unrealized gains and losses on these contracts are recorded in income in the period in which they occur. These contracts generally have maturities of twelve months or less.
In addition, certain of the Company's investment managers may, subject to investment guidelines, enter into forward contracts.
Investment Related Derivatives – Credit Exposure
Credit derivatives may be purchased within the Company's investment portfolio in the form of single name and basket credit default swaps, which are used to mitigate credit exposure through a reduction in credit spread duration (i.e., macro credit strategies rather than single-name credit hedging) or exposure to selected issuers, including issuers that are not held in the underlying fixed income portfolio.
Investment Related Derivatives – Financial Market Exposure
Stock index futures may be purchased within the Company's investment portfolio in order to create synthetic equity exposure and to add value to the portfolio with overlay strategies where market inefficiencies are believed to exist. From time to time, the Company may enter into other financial market exposure derivative contracts on various indices including, but not limited to, inflation and commodity contracts.
(d)(ii) Financial Operations Derivatives – Credit Exposure
At December 31, 2013, the Company held one financial operations credit derivative exposure, a European project finance loan participation that benefited from a deficiency guarantee from the German state and federal governments in the amount of 68%, which was written as part of the Company's previous financial lines business and is outside of the Company's investment portfolio.
During the fourth quarter of 2014, this credit derivative exposure was terminated. The Company has no continuing financial operations derivatives credit exposure.
(d)(iii) Other Non-Investment Derivatives
Other Non-Investment Derivatives - Credit Exposure
During the year ended December 31, 2014, the Company entered into a non-investment-related credit derivative relating to a number of reference pool mortgage tranches associated with actual mortgage loans which are securitized into agency mortgage-backed securities and sold as Structured Agency Credit Risk Notes. At December 31, 2014, there was no reported event of default on this obligation. At December 31, 2014, the notional outstanding related to the derivative was $31.1 million and the Company had recorded a derivative asset of $0.1 million. During the year ended December 31, 2014, the Company recorded Net realized and unrealized gains of $0.1 million relating to this credit derivative. The credit derivative is recorded at fair value based upon models developed by the Company. Significant unobservable inputs considered in the valuation include the impact of changes in interest rates, future default, delinquency and prepayment rates, credit spreads, changes in credit quality, and other market factors.
Guaranteed Minimum Income Benefit Contract
The Company also has derivatives embedded in certain reinsurance contracts. For a certain life reinsurance contract, the Company pays the ceding company a fixed amount equal to the estimated present value of the excess of the guaranteed benefit over the account balance upon the policyholder's election to take the income benefit. The fair value of this derivative is determined based on the present value of expected cash flows.
Modified Coinsurance Funds Withheld Contract
The Company has modified coinsurance and funds withheld reinsurance agreements that provide for a return to be paid to the Company based on a portfolio of fixed income securities. As such, the agreements contain an embedded derivative. The embedded derivative is bifurcated from the funds withheld balance and recorded at fair value with changes in fair value recognized in earnings through Net realized and unrealized gains (losses) on derivative instruments.
Modified Coinsurance Funds Withheld Reinsurance Agreements - Life Retrocession Embedded Derivative
In addition, the Company has entered into Life Retro Arrangements as described in Note 2, "Significant Accounting Policies - (c) Investments - Investments Related to Life Retrocession Arrangements written on a Funds Withheld Basis" and " - (e) Reinsurance," and Note 3, "Sale of Life Reinsurance Subsidiary." The embedded derivative related to the Life Retro Arrangements is recorded at fair value with changes in fair value recognized in earnings through Net realized and unrealized gains (losses) on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets.
The value of the life retrocession embedded derivative includes the interest income, realized and unrealized gains and losses on Life Funds Withheld Assets and certain related expenses subsequent to May 30, 2014 as follows:


Components of Life Retrocession Embedded Derivative and Derivative Instruments - Life Funds Withheld Assets:
(U.S. dollars in thousands)	2014
Interest income	$	(134,634	)
Realized and unrealized gains (losses) on Life Funds Withheld Assets	(318,065		)
Other	1,868
Other	1,868
Net realized and unrealized gains (losses) on life retrocession embedded derivative	$	(450,831	)
Net adjustments related to future policy benefit reserves, net of tax	$	(21,786	)
Net realized and unrealized gains (losses) on derivative instruments - Life Funds Withheld Assets	$	(15,605	)
Net realized and unrealized gains (losses) on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets	$	(488,222	)
(e) Contingent Credit Features
Certain derivative agreements entered into by the Company or its subsidiaries contain credit rating downgrade provisions that permit early termination of the agreements by the counterparty if collateral is not posted following failure to maintain certain credit ratings from one or more of the principal credit rating agencies. If the Company were required to early terminate such agreements due to a credit rating downgrade, it could potentially be in a net liability position at the time of settlement of such agreements. The aggregate fair value of all derivative agreements containing such rating downgrade provisions that were in a liability position and any collateral posted under these agreements at December 31 for the years indicated were as follows:


Contingent Credit Features - Summary:	2014			2013
(U.S. dollars in thousands)	2014			2013
Aggregate fair value of derivative agreements with downgrade provisions in a net liability position	$	5,770		$	47,703
	$	5,770		$	47,703
Collateral posted to counterparty	$	—		$	13,260
Collateral posted to counterparty	$	—		$	13,260

OffBalance_Sheet_Arrangements

Off-Balance Sheet Arrangements	12 Months Ended
Off-Balance Sheet Arrangements	Dec. 31, 2014
Off-Balance Sheet Arrangements Disclosure [Abstract]
Off-balance sheet arrangements	Off-Balance Sheet Arrangements
Off-balance sheet arrangements	There were no material off-balance sheet arrangements at December 31, 2014 and 2013.

Variable_Interest_Entities

Variable Interest Entities	12 Months Ended
Variable Interest Entities	Dec. 31, 2014
Variable Interest Entities Disclosure [Abstract]
Variable interest entities	Variable Interest Entities
	At times, the Company has utilized variable interest entities (“VIEs”) both indirectly and directly in the ordinary course of the Company's business.
	The Company invests in CDOs and other investment vehicles that are issued through VIEs as part of the Company's investment portfolio. The activities of these VIEs are generally limited to holding the underlying collateral used to service investments therein. The Company's involvement in these entities is passive in nature. The Company has not been involved in establishing these entities and is not the primary beneficiary of these VIEs as contemplated in current authoritative accounting guidance.
	The Company has a limited number of remaining outstanding credit enhancement exposures, including written financial guarantee and credit default swap contracts. The obligations related to these transactions are often securitized through VIEs. The Company is not the primary beneficiary of these VIEs as contemplated in current authoritative accounting guidance on the basis that management does not believe that the Company has the power to direct the activities, such as asset selection and collateral management, which most significantly impact each entity's economic performance. For further details on the nature of the obligations and the size of the Company's maximum exposure, see Note 16, “Derivative Instruments,” and Note 19(h), “Commitments and Contingencies – Financial Guarantee Exposures.”
	During the third quarter of 2013, the Company, along with other investors, formed a new Bermuda-based company, New Ocean Capital Management Limited (“New Ocean”), to act as an investment manager that focuses on providing third-party investors access to insurance-linked securities and other insurance and reinsurance capital markets products. The Company holds a majority voting interest in New Ocean through its ownership of common shares and, accordingly, the financial statements of New Ocean have been included in the consolidated financial statements of the Company. None of the assets, liabilities, revenues or net income of New Ocean was material to the Company during the current year. The equity interest attributable to third party investors in New Ocean recorded in the Company’s Consolidated Balance Sheets as "Non-controlling interest in equity of consolidated subsidiaries" was $0.2 million and $0.3 million at December 31, 2014 and December 31, 2013, respectively.
	During the fourth quarter of 2013, the Company, along with other investors, formed a new Bermuda-based investment company, New Ocean Focus Cat Fund Ltd. ("New Ocean FCFL"), which is considered a VIE under GAAP. During the year ended December 31, 2014, New Ocean FCFL invested in a special purpose reinsurer, Vector Reinsurance Ltd (“Vector Re”), formed for the purpose of underwriting collateralized excess of loss reinsurance with a focus on global property catastrophe risks. Most of Vector Re’s current underwriting activity relates to reinsurance business assumed from XL subsidiaries. Underwriting administration and claims services are provided to Vector Re by XL under service fee contracts which management believes were negotiated at arm's-length, while investment advisory services are provided by New Ocean.
	The Company currently holds majority equity interests, which are considered to be the controlling financial interests, in New Ocean FCFL and Vector Re. Accordingly, included in the consolidated financial statements of the Company are New Ocean FCFL's and Vector Re's total net assets of $93.9 million and $46.5 million at December 31, 2014 and December 31, 2013, respectively. The Company’s share of revenue and net income in these VIEs was not material to the Company for the twelve months ended December 31, 2014. All inter-company transactions between XL entities have been eliminated in consolidation. The equity interest attributable to third party investors in New Ocean FCFL and Vector Re recorded in the Company’s Consolidated Balance Sheets as "Non-controlling interest in equity of consolidated subsidiaries" was $57.4 million and $6.9 million at December 31, 2014 and December 31, 2013, respectively.
	During the second quarter of 2014, the Company formed another new Bermuda-based investment company, New Ocean Market Value Cat Fund, Ltd. ("New Ocean MVCFL"), which is also considered a VIE under GAAP. New Ocean MVCFL invests in insurance-linked securities, with a current primary focus on catastrophe bonds. An additional investor joined New Ocean MVCFL in the fourth quarter of 2014, but the Company still holds a majority equity interest which is considered to be the controlling financial interest. Accordingly, included in the consolidated financial statements of the Company are New Ocean MVCFL's total net assets of $46.1 million at December 31, 2014. The Company's share of revenue and net income in New Ocean MVCFL was not material for the twelve months ended December 31, 2014. The equity interest attributable to the third party investor in New Ocean MVCFL recorded in the Company’s Consolidated Balance Sheets as "Non-controlling interest in equity of consolidated subsidiaries" was $1.0 million at December 31, 2014.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	(a) Concentrations of Credit Risk
	The creditworthiness of any counterparty is evaluated by the Company, taking into account credit ratings assigned by rating agencies. The credit approval process involves an assessment of factors including, among others, the counterparty and country and industry credit exposure limits. Collateral may be required, at the discretion of the Company, on certain transactions based on the creditworthiness of the counterparty.
	The areas where significant concentrations of credit risk may exist include unpaid losses and loss expenses recoverable and reinsurance balances receivable (collectively, “reinsurance assets”) and in the investment fixed income portfolio.
	Reinsurance Assets
	The Company’s reinsurance assets result from reinsurance arrangements in the course of its operations. A credit exposure exists with respect to reinsurance assets as they may be uncollectible. The Company manages its credit risk in its reinsurance relationships by transacting with reinsurers that it considers financially sound, and if necessary, the Company may hold collateral in the form of funds, trust accounts and/or irrevocable letters of credit. This collateral can be drawn on for amounts that remain unpaid beyond specified time periods on an individual reinsurer basis. For further details regarding the Company’s reinsurance assets, see Note 10, “Reinsurance.”
	Fixed Income Portfolio
	The Company did not have an aggregate direct investment in any single corporate issuer in excess of 5% of the Company's shareholders’ equity at December 31, 2014 and 2013. Corporate issuers represent only direct exposure to fixed maturities and short-term investments of the parent issuer and its subsidiaries. These exposures exclude asset and mortgage back securities that were issued, sponsored or serviced by the parent and government-guaranteed issues, but does include covered bonds.
	Broker credit risk
	In addition, the Company underwrites a significant amount of its insurance and reinsurance property and casualty business through brokers and a credit risk exists should any of these brokers be unable to fulfill their contractual obligations with respect to the payments of insurance and reinsurance balances to the Company. During the three years ended December 31, 2014, 2013 and 2012, P&C gross written premiums generated from or placed by the below companies individually accounted for more than 10% of the Company’s consolidated gross written premiums from P&C operations, as follows:


	(Percentage of consolidated gross written premiums from P&C operations)	2014		2013			2012
	AON Corporation and subsidiaries	18	%	21	%		22	%
	Marsh & McLennan Companies	20	%	23	%		21	%
	Willis Group and subsidiaries	11	%	13	%		11	%
	These brokers are large, well established companies and there are no indications that any of them are financially troubled. No other broker and no one insured or reinsured accounted for more than 10% of gross premiums written from P&C operations in any of the three years ended December 31, 2014, 2013 and 2012.
	(b) Other Investments
	The Company has committed to invest in several limited partnerships and provide liquidity financing to a structured investment vehicle. At December 31, 2014, the Company has commitments, which include potential additional add-on clauses, to invest an additional $107.3 million over a weighted average period of 7.7 years.
	(c) Investments in Affiliates
	The Company owns a minority interest in certain closed-end funds, certain limited partnerships and similar investment vehicles, including funds managed by those companies. At December 31, 2014, the Company has commitments, which include potential additional add-on clauses, to invest an additional $112.8 million over a weighted average period of 6.9 years.
	(d) Properties
	The Company rents space for certain of its offices under leases that expire through 2031. Total rent expense under operating leases for the years ended December 31, 2014, 2013 and 2012 was approximately $36.6 million, $38.7 million and $35.6 million, respectively. Future minimum rental commitments under existing operating leases are expected to be as follows:


	Year Ended December 31,
	(U.S. dollars in thousands)
	2015	$	36,949

	2016	32,027

	2017	28,933

	2018	25,156

	2019	24,086

	2020-2031	73,269

	Total minimum future rentals	$	220,420

	During 2003, the Company entered into a purchase, sale and leaseback transaction to acquire new office space in London. The Company has recognized a capital lease asset of $82.8 million and $94.4 million, and deferred a gain of $25.2 million and $28.7 million related to this lease at December 31, 2014 and 2013, respectively. The gain is being amortized to income in line with the amortization of the asset. The future minimum lease payments in the aggregate are expected to be $191.4 million and annually for the next five years are as follows:


	Year Ended December 31,
	(U.S. dollars in thousands)
	2015	$	12,095

	2016	12,398

	2017	12,708

	2018	13,025

	2019	13,351

	2020-2028	127,787

	Total minimum future lease payments	$	191,364

	(e) Tax Matters
	XL-Ireland is an Irish corporation and, except as described below, neither it nor its non-U.S. subsidiaries have paid U.S. corporate income taxes on the basis that they are not engaged in a trade or business or otherwise subject to taxation in the United States. However, because definitive identification of activities that constitute being engaged in a trade or business in the United States is not provided by the Internal Revenue Code of 1986 ("IRS Code"), regulations or court decisions, there can be no assurance that the Internal Revenue Service will not contend that the Company or its non-U.S. subsidiaries are engaged in a trade or business or otherwise subject to taxation in the United States. If the Company or its non-U.S. subsidiaries were considered to be engaged in a trade or business in the United States (and, if the Company or such subsidiaries were to qualify for the benefits under the income tax treaty between the United States and Bermuda and other countries in which the Company operates, such businesses were considered to be attributable to a “permanent establishment” in the United States), the Company or such subsidiaries could be subject to U.S. tax at regular tax rates on their respective taxable income that is effectively connected with their U.S. trade or business plus an additional “branch profits” tax (at a rate as high as 30%) on such income remaining after the regular tax, in which case there could be a significant adverse effect on the Company’s results of operations and financial condition.
	(f) Letters of Credit
	At December 31, 2014 and 2013, $1.8 billion and $1.9 billion of letters of credit were outstanding, of which 66.2% and 67.6%, respectively, were collateralized by the Company’s investment portfolios, primarily supporting U.S. non-admitted business and the Company’s Lloyd’s syndicates’ capital requirements.
(g) Litigation
The Company and its subsidiaries are subject to litigation and arbitration in the normal course of business. These lawsuits and arbitrations principally involve claims on policies of insurance and contracts of reinsurance and are typical for the Company and for the property and casualty insurance and reinsurance industry in general. Such claims proceedings are considered in connection with the Company's loss and loss expense reserves. Reserves in varying amounts may or may not be established in respect of particular claims proceedings based on many factors, including the legal merits thereof. In addition to litigation relating to insurance and reinsurance claims, the Company and its subsidiaries are subject to lawsuits and regulatory actions in the normal course of business that do not arise from or directly relate to claims on insurance or reinsurance policies. This category of business litigation typically involves, among other things, allegations of underwriting errors or misconduct, employment claims, regulatory activity, shareholder disputes or disputes arising from business ventures. The status of these legal actions is actively monitored by management.
Legal actions are subject to inherent uncertainties, and future events could change management's assessment of the probability or estimated amount of potential losses from pending or threatened legal actions. Based on available information, it is the opinion of management that the ultimate resolution of pending or threatened legal actions other than claims proceedings, both individually and in the aggregate, will not result in losses having a material adverse effect on the Company's financial position or liquidity at December 31, 2014.
If management believes that, based on available information, it is at least reasonably possible that a material loss (or additional material loss in excess of any accrual) will be incurred in connection with any legal actions, the Company discloses an estimate of the possible loss or range of loss, either individually or in the aggregate, as appropriate, if such an estimate can be made, or discloses that an estimate cannot be made. Based on the Company's assessment at December 31, 2014, no such disclosures were considered necessary.
(h) Financial Guarantee Exposures
A summary of the Company's outstanding financial guarantee exposures for the years indicated is as follows:


Financial Guarantee Exposure Summary	2014			2013
(U.S. dollars in thousands except number of contracts and term to maturity)
Opening number of financial guarantee contracts	3			4

Number of financial guarantee contracts matured, prepaid or commuted during the period	(1		)	(1		)
Closing number of financial guarantee contracts	2			3

Principal outstanding	$	80,813		$	108,255

Interest outstanding	$	—		$	—

Aggregate exposure outstanding	$	80,813		$	108,255

Total gross claim liability recorded	$	—		$	—

Total unearned premiums and fees recorded	$	—		$	134

Weighted average contractual term to maturity in years	25.2			26

The Company's outstanding financial guarantee contracts at December 31, 2014 provide credit support for a variety of collateral types with the exposures comprised of a $80.8 million notional financial guarantee on two notes backed by zero coupon long dated bonds and bank perpetual securities, including some issued by European financials. At December 31, 2014, there were no reported events of default on these obligations.
Surveillance procedures to track and monitor credit deteriorations in the insured financial obligations are performed by the primary obligors for each transaction on the Company's behalf. Information regarding the performance status and updated exposure values is provided to the Company on a quarterly basis and evaluated by management in recording claims reserves.

Share_Capital

Share Capital	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Share capital	Share Capital
	(a) Authorized and Issued
	The authorized share capital of XL-Ireland is $9,999,900 and €40,000, divided into: (i) 500,000,000 ordinary shares, par value $0.01 each, (ii) 499,990,000 undesignated shares, par value $0.01, each and (iii) 40,000 subscriber shares, par value €1 each. Holders of ordinary shares are entitled to one vote for each share.
	Ordinary Shares
	The following table is a summary of ordinary shares issued and outstanding:


	(in thousands)	2014			2013
	Balance – beginning of year	278,253			298,682

	Exercise of options	424			927

	Net issuance of restricted shares	1,246			1,240

	Share buybacks (1)	(24,740	)		(22,596	)
	Balance – end of year	255,183			278,253

	____________

	-1	Includes share buybacks associated with authorized share buyback programs as well as purchases related to satisfying tax withholding obligations of employees in connection with the vesting of restricted shares granted under the Company’s equity compensation programs.
	Ordinary Share Buybacks
	On February 22, 2013, XL-Ireland announced that its Board of Directors approved a new share buyback program, authorizing the purchase of up to $850 million of its ordinary shares (the “Share Buyback Program”). This authorization replaced the previous Program.
	At December 31, 2013, $275.0 million remained available for purchase under the Share Buyback Program. On February 21, 2014, XL-Ireland announced that its Board of Directors approved an increase to the Share Buyback Program, authorizing the purchase of up to $1.0 billion of our ordinary shares. This authorization includes the approximately $200.0 million that remained under the Share Buyback Program prior to the increase.
	During the year ended December 31, 2014, the Company purchased and canceled 24.7 million shares for $800.0 million at an average price of $32.40 per share. At December 31, 2014, $267.6 million remained available for purchase under the February 2014 Program.
	All share buybacks were carried out by way of redemption in accordance with Irish law and the Company's constitutional documents. All shares so redeemed were canceled upon redemption.
	(b) Non-controlling Interest in Equity of Consolidated Subsidiaries
	All of the preferred shares discussed in this section were issued by XL-Cayman and do not represent share capital of XL-Ireland. XL-Ireland has no preferred shares outstanding and has never issued any preferred shares.
	Series D Preference Ordinary Shares
	On October 15, 2011, XL-Cayman issued $350 million Series D Preference Ordinary Shares. Dividends on the Series D Preference Ordinary Shares are declared and paid quarterly at a floating rate of three-month LIBOR plus 3.120% on the liquidation preference. XL-Cayman used the consideration it received as partial funding for the repayment at maturity of the outstanding $600 million XLCFE Notes that were issued by XLCFE, with the balance available for general corporate purposes.
	Series E Preference Ordinary Shares
	On March 15, 2007, XL-Cayman issued 1.0 million Fixed/Floating Series E Perpetual Non-Cumulative preference ordinary shares, par value $0.01 each, with liquidation preference value of $1,000 per share (the “Series E preference ordinary shares”). XL-Cayman received net proceeds of approximately $983.8 million from the offering. The Series E preference ordinary shares are perpetual securities with no fixed maturity date and are not convertible. Dividends on the Series E preference ordinary shares are declared and paid semi-annually at a rate of $32.50 per share.
	(c) Stock Plans
	The Company’s performance incentive programs provide for grants of stock options, restricted stock, restricted stock units, performance units and stock appreciation rights. Share-based compensation granted by the Company generally contains a vesting period of three or four years, and certain awards also contain performance conditions. The Company records compensation expense related to each award over its vesting period, incorporating the best estimate of the expected outcome of performance conditions where applicable. Compensation expense is generally recorded on a straight line basis over the vesting period of an award.
	In connection with, and effective upon, the completion of the Redomestication, XL-Ireland assumed the existing liabilities, obligations and duties of XL-Cayman under the NAC Re Corp. 1989 Stock Option Plan (the “1989 Plan”), the XL Group plc Amended and Restated 1991 Performance Incentive Program (the “1991 Program”), the XL Group plc Amended and Restated 1999 Performance Incentive Program for Employees (the “1999 Program”), the XL Group plc Directors Stock & Option Plan (the “Directors Plan”), the XL Group plc 2009 Cash Long-Term Incentive Program (the “2009 Program”), the XL Group plc Supplemental Deferred Compensation Plan (the “DC Plan,” and together with the 1989 Plan, 1991 Program, the 1999 Program, the Directors Plan and the 2009 Program, the “Programs”). Furthermore, in connection with, and effective upon, the completion of the Redomestication, the Programs were amended by XL-Cayman, among other things, to (i) provide that XL-Ireland and its Board of Directors will succeed to all powers, authorities and obligations of XL-Cayman and its Board of Directors under each Program, (ii) provide that the securities to be issued pursuant to each Program will consist of ordinary shares of XL-Ireland and (iii) otherwise to reflect the completion of the Redomestication.
	(d) Options
	The fair value of each option grant is estimated on the date of grant using the Black-Scholes option pricing model with the following weighted average assumptions:


		2014			2013			2012
	Dividend yield	2	%		2	%		1.9	%
	Risk free interest rate	1.81	%		1.14	%		1.15	%
	Volatility	34	%		37	%		46	%
	Expected lives	6.0 years			6.0 years			6.0 years

	The risk free interest rate is based on U.S. Treasury rates. The expected lives are estimated using the historical exercise behavior of grant recipients. The expected volatility is determined based upon a combination of the historical volatility of the Company’s stock and the implied volatility derived from publicly traded options.
	The following is a summary of the activity in the stock option plans for the indicated years ended December 31:


	(In thousands except for weighted average grant date fair value)	2014				2013				2012
	Options granted to purchase ordinary shares under directors and employees incentive compensation plans - in thousands	1,025				1,047				1,209

	Weighted average grant date fair value	$	8.6			$	8.34			$	7.65

	Total intrinsic value of stock options exercised	$	7,499			$	16,076			$	3,357

	Options exercised during the year - in thousands	424				927				383

	Compensation expense related to stock option plans	$	9,961			$	8,294			$	7,716

	Estimated tax benefit (charge) related to stock option plans	$	(2	)		$	50			$	26

	The following is a summary of the stock options outstanding at December 31, 2014, and related activity for the year then ended:


	Number of Shares (*in thousands*)			Weighted				Weighted		Aggregate
				Average				Average		Intrinsic
				Exercise				Remaining		Value
				Price				Contractual		(in thousands)
								Term
Outstanding – beginning of year	11,123			$	36.91			4.8 years		$	74,927

Granted	1,025			30.42

Exercised	(424	)		15.04

Canceled/Expired	(1,199	)		78.46

Outstanding – end of year	10,525			$	32.42			4.8 years		$	86,690

Options exercisable	8,400			$	33.53			3.9 years		$	73,153

Available for grant (1)	10,316


(1) Available for grant includes shares that may be granted as either stock options, restricted stock, restricted stock units or performance units.
The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value (the difference between the Company’s closing stock price on the last trading day of the 2014 fiscal year and the exercise price, multiplied by the number of in-the-money-options) that would have been received by the option holders had all option holders exercised their options on December 31, 2014. Total unrecognized stock-based compensation expense related to non-vested stock options was approximately $10.4 million at December 31, 2014, which related to approximately 2.1 million options and is expected to be recognized over a weighted-average period of 1.3 years. The exercise price of the Company’s outstanding options granted is the market price of the Company’s ordinary shares on the grant date, except that during 2004, 295,000 options were granted with an exercise price of $88.00 when the market price was $77.10.
(e) Restricted Stock, Restricted Stock Units and Performance Units
Restricted Stock
Restricted stock awards issued under the 1991 Performance Incentive Program and the Directors Stock and Option Plan vest as set forth in the applicable award agreements. Each restricted stock award represents the Company’s obligation to deliver to the holder one ordinary share. The employees and directors who are granted a restricted stock award shall have all the rights of a shareholder, including the right to vote and receive dividends, but the shares are subject to certain restrictions prior to vesting relating to, among other things, forfeiture in the event of termination of employment and transferability.
A summary of the restricted stock awards issued under the 1991 Performance Incentive Program and the Directors Stock and Option Plan for the indicated years ended December 31 is as follows:


(In thousands except for weighted average grant date fair value)	2014				2013				2012
Restricted ordinary shares granted	46				181				325

Weighted average grant date fair value	$	31.86			$	29.44			$	20.92

Aggregate grant date fair value	$	1,463			$	5,325			$	6,811

Compensation expense related to restricted stock awards	$	5,239			$	4,419			$	5,399

Estimated tax benefit related to restricted stock awards	$	1,233			$	1,047			$	1,113

Total unrecognized stock based compensation expense related to non-vested restricted stock awards was approximately $2.5 million at December 31, 2014, which is related to approximately 0.4 million restricted stock awards and is expected to be recognized over one year.
Non-vested restricted stock awards at December 31, 2014 and for the year then ended were as follows:


(In thousands except for weighted average grant date fair value)	Number of			Weighted
	Shares			Average Grant
				Date Fair Value
Unvested at December 31, 2013	593			$	33.92

Granted	46			$	31.86

Vested	(201	)		$	27.79

Forfeited	(5	)		$	44.01

Unvested at December 31, 2014	433			$	36.41

Restricted Stock Units
Each restricted stock unit represents the Company’s obligation to deliver to the holder one ordinary share upon satisfaction of the three-year vesting term. Restricted stock units are granted at the closing market price on the day of grant and entitle the holder to receive dividends declared and paid in the form of additional ordinary shares contingent upon vesting.
A summary of the restricted stock units issued to officers of the Company and its subsidiaries for the indicated years ended December 31 is as follows:


(In thousands)	2014				2013				2012
Restricted stock units granted	1,867				1,803				1,312

Aggregate grant date fair value	$	57,134			$	51,829			$	27,194

Compensation expense related to restricted stock units	$	41,879			$	32,874			$	24,451

Estimated tax benefit related to restricted stock units	$	11,607			$	8,813			$	6,501

Total unrecognized stock-based compensation expense related to non-vested restricted stock units was approximately $60.1 million at December 31, 2014, which is related to approximately 3.2 million restricted stock units and is expected to be recognized over 1.4 years.
Non-vested restricted stock units at December 31, 2014 and for the year then ended were as follows:


(In thousands except for weighted average grant date fair value)	Number of			Weighted
	Shares			Average Grant
				Date Fair Value
Unvested at December 31, 2013	2,931			$	25.77

Granted	1,867			$	30.6

Vested	(1,388	)		$	24.8

Forfeited	(162	)		$	28.05

Unvested at December 31, 2014	3,248			$	28.93

Performance Units
The performance units vest after three years and entitle the holder to shares of the Company’s stock. There are no dividend rights associated with the performance units. Each grant of performance units has a target number of shares, with final payouts ranging from 0% to 200% of the grant amount depending upon a combination of corporate and business segment performance along with each employee’s continued service through the vesting date. Performance targets are based on relative and absolute financial performance metrics. A summary of the performance units issued to certain employees of the Company for the indicated years ended December 31 is as follows:


(In thousands)	2014				2013				2012
Performance units granted	572				656				1,527

Potential maximum share payout	1,144				1,312				3,054

Aggregate grant date fair value	$	16,345			$	17,753			$	29,537

Compensation expense related to performance units	$	24,089			$	1,041			$	9,919

Estimated tax benefit (charge) related to performance units	$	4,250			$	(176	)		$	1,943

Total unrecognized stock-based compensation expense related to non-vested performance units was approximately $27.8 million at December 31, 2014, which is related to approximately 2.5 million performance units and is expected to be recognized over 1.8 years. Non-vested restricted performance units as of December 31, 2014 were as follows:


(In thousands except for weighted average grant date fair value)	Number of			Weighted
	Shares			Average Grant
				Date Fair Value
Unvested at December 31, 2013	1,687			$	22.99

Granted	572			$	28.57

Vested	(340	)		$	22.06

Forfeited	(100	)		$	25.98

Performance driven addition (reduction)	721			$	26.46

Unvested at December 31, 2014	2,540			$	25.24

(f) Voting
XL-Ireland’s Articles of Association restrict the voting power of any person to less than approximately 10% of the total voting power.

Retirement_Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Retirement plans	Retirement Plans
	The Company provides pension benefits to eligible employees through various defined contribution and defined benefit retirement plans sponsored by the Company, which vary for each subsidiary. Plan assets are invested principally in equity securities and fixed maturities.
	(a) Defined contribution plans
	The Company has qualified defined contribution plans that are managed externally and to which employees and the Company contribute a certain percentage of the employee’s pensionable salary each month. The Company’s contribution generally vests over five years. The Company’s expenses for its qualified contributory defined contribution retirement plans were $56.6 million, $49.4 million and $53.6 million at December 31, 2014, 2013 and 2012, respectively.
	(b) Defined benefit plans
	The Company maintains defined benefit plans that cover certain employees as follows:
	U.S. Plan
	A qualified non-contributory defined benefit pension plan exists to cover a number of U.S. employees. The plan was curtailed in 2002 and was closed to new entrants at that time. Under the terms of the curtailment, existing plan participants were no longer entitled to earn additional defined benefits for future services performed after the curtailment date; however, accrued benefits are eligible for annual cost-of-living increases. This plan also includes a non-qualified supplemental defined benefit plan designed to compensate individuals to the extent that their benefits under the Company’s qualified plan are curtailed due to IRS Code limitations. Benefits are based on years of service and compensation, as defined in the plan, during the highest consecutive three years of the employee’s last ten years of employment.
	In addition, pursuant to agreements entered into by the Company, certain former employees have received benefit type guarantees, not formally a part of any established plan. The liability recorded with respect to these agreements at December 31, 2014 and 2013 was $3.2 million and $3.0 million, respectively, representing the entire unfunded projected benefit obligations.
	U.K. Plans
	A contributory defined benefit pension scheme exists in the U.K., but has been closed to new entrants since 1996. Benefits are based on length of service and compensation as defined in the trust deed and rules.
	In addition, during 2003, six individuals, four of whom are still employed by the Company in the U.K., transferred from a defined benefit plan into a defined contribution plan. These employees have a contractual agreement with the Company that provides a “no worse than final salary pension” guarantee in the event that they are employed by the Company until retirement, under which the Company guarantees to top-up their defined contribution pension to the level of pension that they would have been entitled to receive had they remained in the defined benefit scheme. The pension liability recorded with respect to these individuals was $3.8 million and $4.0 million at December 31, 2014 and 2013, respectively, representing the entire unfunded projected obligation.
	Other European Plans
	Certain contributory defined benefit pension plans exist in several European countries, most notably Germany, which are closed to new entrants. Benefits are generally based on length of service and compensation defined in the related agreements.
	As a part of the purchase of XL GAPS, the Company acquired certain defined benefit pension liabilities. The related balances are not included in the tables below as the liabilities are insured under an annuity type contract.
	The funded status by geographical region of all the Company’s retirement plans at December 31, 2014 and 2013 is as follows:


	Funded Status	2014				2013
	(U.S. dollars in thousands)
	U.S.	$	(13,124	)		$	(6,181	)
	U.K.	(7,742		)		(7,654		)
	Other European	(22,977		)		(20,983		)
	Funded status – end of year	$	(43,843	)		$	(34,818	)
	The status of all the Company’s retirement plans at December 31, 2014 and 2013 is as follows:


	Change in projected benefit obligation	2014				2013
	(U.S. dollars in thousands)
	Projected benefit obligation – beginning of year	$	81,976			$	83,083

	Service cost (1)	1,279				1,491

	Interest cost	3,747				3,599

	Actuarial (gain) / loss	13,402				(5,091		)

	Benefits and expenses paid	(2,761		)		(2,307		)
	Foreign currency (gains) / losses	(3,817		)		1,201

	Settlements	(702		)		—

	Projected benefit obligation – end of year	$	93,124			$	81,976

	(1) Service costs include cost of living adjustments on curtailed plans.


	Change in plan assets	2014				2013
	(U.S. dollars in thousands)
	Fair value of plan assets – beginning of year	$	47,158			$	39,313

	Actual return on plan assets	3,543				6,113

	Employer contributions	1,187				2,919

	Benefits and expenses paid	(1,932		)		(1,462		)
	Foreign currency gains / (losses)	(675		)		275

	Fair value of plan assets – end of year	$	49,281			$	47,158

	Funded status – end of year	$	(43,843	)		$	(34,818	)
	Accrued pension liability	$	43,843			$	34,818

	The components of the net benefit cost for the years ended December 31, 2014, 2013 and 2012 are as follows:


Components of net benefit cost	2014				2013				2012
(U.S. dollars in thousands)
Service cost	$	1,279			$	1,491			$	1,291

Interest cost	3,747				3,589				3,557

Expected return on plan assets	(2,859		)		(3,096		)		(3,028		)
Amortization of net actuarial loss	812				1,440				915

Transfer from AOCI	—				—				3,363

Net benefit cost	$	2,979			$	3,424			$	6,098

Assumptions
Several assumptions and statistical variables are used in the models to calculate the expenses and liability related to the plans. The Company, in consultation with its actuaries, determines assumptions about the discount rate, the expected rate of return on plan assets and the rate of compensation increase. The table below includes disclosure of these rates on a weighted-average basis, for the years ended December 31 as indicated:


	2014									2013
	U.S. Plans			U.K. Plans			Other European Plans			U.S. Plans			U.K. Plans		Other European Plans
Net Benefit Cost – Weighted-average assumptions
Discount rate	4.95	%		4.6	%		3.5	%		4	%		4.5	%	4.2	%
Expected long-term rate of return on plan assets	6.5	%		4.6	%		N/A			8	%		5.7	%	N/A

Rate of compensation increase	N/A			5.5	%		2.5	%		N/A			4.9	%	2.5	%

Benefit Obligation – Weighted-average assumptions
Discount rate	3.91	%		4.6	%		2.4	%		4.95	%		4.5	%	3.5	%
Rate of compensation increase	N/A			5.5	%		2.5	%		N/A			4.9	%	2.5	%

The expected long-term rate of return assumption is determined by adding expected inflation to the expected long-term real rates of various asset classes taking into account expected volatility and correlation between the various asset classes.
Plan Assets
The U.S. Plan assets at December 31, 2014 and 2013 consist of two mutual funds. The first fund employs a core bond portfolio strategy that seeks maximum total return and price appreciation consistent with the preservation of capital and prudent risk taking with the focus on intermediate – term high quality bonds.
The second fund seeks long term growth of capital. The fund invests primarily in equity securities and depository receipts of U.S. and foreign issuers. The principal types of equity securities in which the fund invests are common and preferred stocks.
The fair value of the U.S. Plan assets at December 31, 2014 and 2013 was $38.1 million and $36.4 million, respectively. As the investments of the retirement plan are mutual funds, they fall within Level 1 in the fair value hierarchy. The inputs and methodologies used in determining the fair value of these assets are consistent with those used to measure our assets as set out in Note 4, "Fair Value Measurements.”
The U.K. pension plan assets are held in a separate trustee administered fund to meet long term liabilities to past and present employees. The table below shows the composition of the plan's assets and the fair value of each major category of plan assets at December 31, 2014 and 2013, as well as the potential returns of the different asset classes. The totals of the asset values held in various externally managed portfolios are provided by third party pricing vendors. There is no significant concentration of risk within plan assets. The assets in the scheme and the expected rates of return were as follows:


(U.S. dollars in thousands, except percentages)	Expected			Weighted				Expected			Weighted
	Return on			Value at				Return on			Value at
	Assets for			December 31,				Assets for			December 31,
	2014			2014				2013			2013
Equities	7.4	%		$	7,787			6.8	%		$	7,048

Gilts	3.6	%		1,579				3	%		1,775

Corporate Bonds	4.6	%		1,594				4.5	%		1,758

Other (cash)	4	%		224				3.4	%		133

Total market fair value of assets				$	11,184						$	10,714

Expected Cash Flows
Under the U.S. defined benefit plans, the Company’s policy is to make annual contributions to the plan that are deductible for federal income tax purposes and that meet the minimum funding standards required by law. The contribution level is determined by utilizing the projected unit credit cost method and different actuarial assumptions than those used for pension expense purposes. The Company’s funding policy provides that contributions to the plan shall be at least equal to the minimum funding requirements of the Employee Retirement Income Security Act of 1974 (“ERISA”), as amended by the Pension Protection Act of 2006. During the fiscal year beginning January 1, 2015, the U.S. defined benefit plans expect to make contributions of $0.4 million.
The estimated future benefit payments with respect to the U.S. defined benefit pension plans are as follows:


(U.S. dollars in thousands)	Retirement Plan				Benefits Equalization Plan				Total
2015	$	876			$	425			$	1,301

2016	$	925			$	425			$	1,350

2017	$	1,001			$	421			$	1,422

2018	$	1,064			$	424			$	1,488

2019	$	1,255			$	522			$	1,777

2020-2024	$	9,462			$	2,927			$	12,389

The U.K. scheme is subject to triennial funding valuations, the most recent of which was conducted as of July 1, 2012 and was reported in 2013. The $2.4 million deficit (calculated on a realistic basis) is being funded over a 10-year period.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2014
Comprehensive Income Loss Note [Abstract]
Accumulated other comprehensive income (loss)	Accumulated Other Comprehensive Income (Loss)
	The changes in AOCI, net of tax, by component for the indicated years ended December 31 are as follows:


	(U.S. dollars in thousands)	Unrealized Gains (Losses) on Investments (1)				OTTI Losses Recognized in AOCI				Foreign Currency Translation Adjustments			Underfunded Pension Liability			Cash Flow Hedge		Total
	Balance, net of tax, December 31, 2011	$	710,447			$	(188,651	)		$	77,555		$	(17,521	)	$	1,235	$	583,065

	OCI before reclassifications	985,544				—				(6,791		)	(8,126		)	—		970,627

	Amounts reclassified from AOCI	(81,678		)		67,580				350			4,273			439		(9,036		)

	Tax (benefit) expense	(23,103		)		(300		)		(1,715		)	482			—		(24,636		)

	Net current period OCI - net of tax	$	880,763			$	67,280			$	(8,156	)	$	(3,371	)	$	439	$	936,955

	Balance, net of tax, December 31, 2012	$	1,591,210			$	(121,371	)		$	69,399		$	(20,892	)	$	1,674	$	1,520,020

	OCI before reclassifications (1)	(742,768		)		—				(62,934		)	9,722			—		(795,980		)

	Amounts reclassified from AOCI	(119,970		)		32,193				206			1,440			439		(85,692		)

	Tax (benefit) expense	93,960				(12		)		7,870			(3,509		)	—		98,309

	Net current period OCI - net of tax	$	(768,778	)		$	32,181			$	(54,858	)	$	7,653		$	439	$	(783,363	)

	Balance, net of tax, December 31, 2013	$	822,432			$	(89,190	)		$	14,541		$	(13,239	)	$	2,113	$	736,657

	OCI before reclassifications (1)	954,326				—				(26,497		)	(10,877		)	—		916,952

	Amounts reclassified from AOCI	(143,330		)		14,082				87			812			255		(128,094		)

	Tax (benefit) expense	(43,314		)		(939		)		681			2,515			—		(41,057		)

	Net current period OCI - net of tax	$	767,682			$	13,143			$	(25,729	)	$	(7,550	)	$	255	$	747,801

	Balance, net of tax, December 31, 2014	$	1,590,114			$	(76,047	)		$	(11,188	)	$	(20,789	)	$	2,368	$	1,484,458

	____________

	-1	Included in these amounts is the impact of Shadow Adjustments. During the year ended December 31, 2013, the initial impact of $44.7 million was recorded. During the year ended December 31, 2014, additional net impacts of $400.5 million were recorded, resulting in a total cumulative net impact of Shadow Adjustments on future policy benefit reserves of $445.1 million at December 31, 2014.
	The reclassifications out of AOCI along with the associated income statement line items affected by component, and the total related tax (expense) benefit for indicated years ended December 31, are as follows:


	Gross Amount Reclassified From AOCI
	Details About AOCI Components	2014				2013			Affected Line Item in the Statement of Income
	(U.S. dollars in thousands)
	Unrealized gains and losses on investments:
		$	(175,639	)		$	(130,236	)	Net realized gains (losses) on investments sold
		54,095				$	10,266		OTTI on investments

		(21,786		)		$	—		Net realized and unrealized gains (losses) on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets

		$	(143,330	)		$	(119,970	)	Total before tax
		(1,593		)		$	5,183		Provision (benefit) for income tax

		$	(144,923	)		$	(114,787	)	Net of tax
	OTTI losses recognized in OCI:
		$	11,848			$	26,160		Net realized gains (losses) on investments sold

		2,234				$	6,033		OTTI on investments transferred to (from) OCI

		$	14,082			$	32,193		Total before tax

		(175		)		$	(12	)	Provision (benefit) for income tax
	$	13,907			$	32,181		Net of tax

Foreign Currency Translation:
Foreign exchange relating to affiliate investments	$	87			$	206		Exchange gains (losses) - before tax

	—				$	—		Provision (benefit) for income tax

	$	87			$	206		Net of tax


Underfunded Pension Liability:
Pension expense	$	812			$	1,440		Operating Expenses

	(206		)		$	—		Provision (benefit) for income tax

	$	606			$	1,440		Net of tax


Gains and losses on cash flow hedges:
Interest rate contracts	$	255			$	439		Interest Expense

	—				$	—		Provision (benefit) for income tax

	$	255			$	439		Net of tax


Total reclassifications for the period, gross of tax	$	(128,094	)		(85,692		)
Tax (benefit) expense	(1,974		)		5,171

Total reclassifications for the period, net of tax	$	(130,068	)		(80,521		)

Dividends

Dividends	12 Months Ended
Dividends	Dec. 31, 2014
Dividends Disclosure [Abstract]
Dividends	Dividends
	In 2014, four quarterly dividends of $0.16 per share were paid to all ordinary shareholders of record at March 14, June 13, September 15 and December 15. In 2013, four quarterly dividends of $0.14 per share were paid to all ordinary shareholders of record at March 15, June 14, September 13 and December 13. In 2012, four quarterly dividends of $0.11 per share were paid to all ordinary shareholders of record at March 15, June 15, September 14 and December 14.
	XL-Cayman paid dividends to Series D and Series E preference shareholders for the indicated years ended December 31, as follows:


	(U.S. dollars in millions)	2014		2013		2012
	Series D preference ordinary shares (1) (2)	$	11.7	$	12.3	$	14
	Series D preference ordinary shares (1) (2)	$	11.7	$	12.3	$	14
	Series E preference ordinary shares (3)	$	65.1	$	65.1	$	65.1
	Series E preference ordinary shares (3)	$	65.1	$	65.1	$	65.1
	____________

	-1	On October 31, 2014, the Company announced that the Board of Directors of XL-Cayman resolved to pay a dividend of $8.5563 per share on XL-Cayman’s Series D Preference Ordinary Shares. The dividend was paid on January 15, 2015 to all shareholders of record at January 1, 2015.

	-2	On February 20, 2015, the Company announced that the Board of Directors of XL-Cayman, resolved on February 19, 2015 to pay a dividend of $8.4315 per share on XL-Cayman’s Series D Preference Ordinary Shares. The dividend will be paid on April 15, 2015 to all shareholders of record at April 1, 2015.

	-3	On February 20, 2015, the Company announced that the Board of Directors of XL-Cayman, resolved on February 19, 2015 to pay a dividend of $32.50 per share on XL-Cayman’s Series E Preference Ordinary Shares. The dividend will be paid on April 15, 2015 to all shareholders of record at April 1, 2015.

Taxation

Taxation	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Taxation	Taxation
	The Company's Irish operations, including the parent company XL Group plc, are subject to income and capital gains tax in Ireland under applicable Irish law.
	The Company’s Bermuda subsidiaries are not subject to any income, withholding or capital gains taxes under current Bermuda law. In the event that there is a change such that these taxes are imposed, the Bermuda subsidiaries would be exempted from any such tax until March 2035 pursuant to the Bermuda Exempted Undertakings Tax Protection Act 1966, and the Exempted Undertakings Tax Protection Amendment Act 2011.
	The Company’s U.S. subsidiaries are subject to federal, state and local corporate income taxes and other taxes applicable to U.S. corporations. The provision for federal income taxes has been determined under the principles of the consolidated tax provisions of the IRS Code and Regulations thereunder.
	The Company has operations in subsidiary and branch form in various other jurisdictions around the world, including but not limited to the U.K., Switzerland, Ireland, Germany, France, Canada, Brazil and various other countries in Latin America and Asia that are subject to relevant taxes in those jurisdictions.
	Deferred income taxes have not been accrued with respect to certain undistributed earnings of foreign subsidiaries. If the earnings were to be distributed, as dividends or otherwise, such amounts may be subject to withholding taxation in the jurisdiction of the paying entity. The Company does not assert that all earnings arising in the U.S. will be permanently reinvested in that jurisdiction and, accordingly, a provision for withholding taxes arising in respect of current period U.S. earnings has been made. No withholding taxes are accrued with respect to the earnings of the Company’s subsidiaries arising outside the U.S., as it is the intention that all such earnings, which would be subject to withholding tax, will remain reinvested indefinitely.
	The Company’s current corporate structure is such that distribution of earnings from subsidiaries located outside of the U.S. would not be subject to significant incremental taxation. It is not practicable to estimate the amount of additional withholding taxes that might be payable on such earnings due to a variety of factors, including the timing, extent and nature of any repatriation.
	The following table details the years that are the subject of open examinations, by major tax jurisdiction. While the Company cannot estimate with certainty the outcome of these examinations, the Company does not believe that adjustments from open tax years will result in a significant change to the Company's results from operations.


	Jurisdiction	Tax Years
	U.S.	2013
	Ireland	2006 - 2009
	U.K.	2007 - 2010
	Germany	2006 - 2009
	Switzerland	2009 - 2010
	The following table details open tax years that are open to assessment by local tax authorities, in the following major tax jurisdictions.


	Jurisdiction	Tax Years
	U.S.	2011 - 2014
	Ireland	2006 - 2014
	U.K.	2007 - 2010,
		2012 - 2014
	Germany	2007 - 2014
	Switzerland	2009 - 2014
	France	2012 - 2014
	The Company’s income (loss) before income tax and non-controlling interests was distributed between U.S. and non-U.S. for the years ended December 31, 2014, 2013 and 2012 as follows:


	Income (loss) before income tax:	2014				2013				2012
	(U.S. dollars in thousands)
	U.S.	$	228,708			$	188,503			$	50,439

	Non U.S.	137,027				1,025,649				713,972

	Total	$	365,735			$	1,214,152			$	764,411

	The income tax provisions for the years ended December 31, 2014, 2013 and 2012 were as follows:


	(U.S. dollars in thousands)	2014				2013				2012
	Current expense:
	U.S.	$	45,598			$	49,566			$	11,966

	Non U.S.	81,371				41,921				45,614

	Total current expense	$	126,969			$	91,487			$	57,580

	Deferred expense (benefit):
	U.S.	$	8,572			$	700			$	(56,602	)

	Non U.S.	(38,644		)		(14,682		)		33,050

	Total deferred expense (benefit)	$	(30,072	)		$	(13,982	)		$	(23,552	)
	Total tax expense	$	96,897			$	77,505			$	34,028

	The applicable statutory tax rates of the most significant jurisdictions contributing to the overall taxation of the Company are:


	Jurisdiction	Applicable Statutory Taxation Rates
	Ireland (1)	12.5	%
	Ireland (1)	25	%
	Bermuda	—	%
U.S.	35	%
U.K.	21.5	%
Switzerland (2)	7.83	%
Switzerland (2)	21.2	%
Germany	15	%
France	38	%
____________

-1	The different applicable statutory taxation rates in Ireland relate to entities classified as trading or non-trading companies.

-2	The different applicable statutory taxation rates in Switzerland relate to entities classified as trading or holding companies.
The weighted average expected tax provision has been calculated using the pre-tax accounting income (loss) in each jurisdiction multiplied by that jurisdiction’s applicable statutory tax rate. A reconciliation of the difference between the provision for income taxes and the expected tax provision at the weighted average tax rate for the years ended December 31, 2014, 2013 and 2012 is provided below:


(U.S. dollars in thousands)	2014				2013				2012
Expected tax (benefit) provision at weighted average rate	$	132,775			$	43,092			$	53,358

Permanent differences:
Non-taxable (income) loss	(19,870		)		(50,745		)		(42,428		)
Prior year adjustments	5,990				6,067				(622		)

Prior year adjustments on completion of IRS examinations	—				—				(19,192		)

State, local and foreign taxes	47,078				12,225				18,312

Valuation allowance	(181		)		5,754				(16,644		)

Net allocated investment income	3,399				5,949				41,727

Stock options	411				1,501				4,749

Non-deductible expenses	22,556				23,662				16,145

Net realized capital loss carry-forward valuation allowance reduction	(2,916		)		—				(24,473		)

Adjustments related to Life Retro Arrangements	(99,535		)		—				—

Non-taxable reserve release	—				—				3,096

Uncertain tax positions	7,190				30,000				—

Total tax expense	$	96,897			$	77,505			$	34,028

Significant components of the Company’s deferred tax assets and liabilities at December 31, 2014 and 2013 were as follows:


(U.S. dollars in thousands)	2014				2013
Deferred tax asset:
Net unpaid loss reserve discount	$	90,262			$	105,511

Net unearned premiums	72,752				69,811

Compensation liabilities	77,578				62,710

Net operating losses	49,834				89,233

Investment adjustments	13,022				12,573

Pension	8,114				5,695

Bad debt reserve	6,626				7,337

Amortizable goodwill	6,694				7,976

Net unrealized depreciation on investments	1,484				9,984

Stock options	11,985				12,171

Depreciation	7,599				3,501

Net realized capital losses	97,189				140,993

Deferred intercompany capital losses	57,427				69,500

Untaxed Lloyd's result	7,254				2,533

Deferred acquisition costs	11,386				—

Other	2,282				9,638

Deferred tax asset, gross of valuation allowance	$	521,488			$	609,166

Valuation allowance	207,062				261,924

Deferred tax asset, net of valuation allowance	$	314,426			$	347,242

Deferred tax liability:
Net unrealized appreciation on investments	$	63,642			$	28,843

Unremitted earnings	$	5,125			$	6,717

Deferred acquisition costs	2,737				7,057

Currency translation adjustments	3,969				7,195

Regulatory reserves	65,965				131,750

Investment adjustment	12,061				6,112

Untaxed Lloyd’s result	11,422				—

Other	11,260				8,014

Deferred tax liability	$	176,181			$	195,688

Net Deferred Tax Asset	$	138,245			$	151,554


The deferred tax asset and liability balances presented above represent the gross deferred tax asset and liability balances across each tax jurisdiction. The deferred tax asset balances of $204.5 million and $237.9 million at December 31, 2014 and 2013, respectively, and deferred tax liability balances of $66.2 million and $86.3 million at December 31, 2014 and 2013, respectively, disclosed on the consolidated balance sheets include netting of certain deferred tax assets and liabilities within a tax jurisdiction to the extent such netting is consistent with the regulations of the tax authorities in those jurisdictions.
At December 31, 2014 and 2013, the valuation allowance of $207.1 million and $261.9 million, respectively, related primarily to net operating loss carry forwards and realized capital loss carry forwards in the following jurisdictions:


Jurisdiction	2014				2013
(U.S. dollars in thousands)
Switzerland	$	1,459			$	11,457

Ireland	72,363				60,133

U.S.	123,695				175,372

Other	9,545				14,962

Valuation Allowance Total	$	207,062			$	261,924

The reduction in the valuation allowance in 2014 of $54.9 million was primarily due to the release of certain valuation allowances held against capital loss carry-forwards in the U.S.
At December 31, 2014, the Company had U.S. realized capital loss carry forwards of approximately $174.6 million ($61.1 million tax effected). The five year limitation for the utilization of realized capital losses applies to this balance. Losses of $75.6 million will expire at the end of 2015 with another $99.0 million of realized capital losses expiring in future years through 2018. A valuation allowance ($61.1 million) has been established in respect of all of these realized capital losses. At December 31, 2014, the Company also had $164.1 million of U.S. capital losses arising from the sale of investments to an international affiliate ($57.4 million tax effected), against which a valuation allowance of $57.4 million has been established. These losses cannot be utilized to offset any future U.S. realized capital gains, and will not begin to expire, until the underlying assets have been sold to unrelated parties.
At December 31, 2014, net operating loss carry forwards in the U.K. were approximately $84.5 million ($1.9 million tax effected, including a $15.0 million uncertain tax position offset, $16.9 million tax effected excluding the offset) and have no expiration. At December 31, 2014, the Company also had $8.1 million of U.K. capital losses ($1.6 million tax effected), against which a valuation allowance of $1.6 million has been established.
At December 31, 2014, net operating loss carry forwards in Switzerland were approximately $12.1 million. A valuation allowance of $0.8 million has been established in respect of $11.7 million of the Swiss net operating losses.
At December 31, 2014, net operating loss carry forwards in Ireland were approximately $280.8 million, with a further $153.5 million of capital losses carried forward. Although these Irish losses may be carried forward indefinitely, a valuation allowance ($69.6 million) has been established in respect of all of these Irish losses due to the uncertainty surrounding any future loss utilization.
Management has reviewed historical taxable income and future taxable income projections for its U.K. group and has determined that in its judgment substantially all of the U.K. net operating losses ($84.5 million) will more likely than not be realized as reductions to future taxable income within a reasonable period. Management will continue to evaluate income generated in future periods by the U.K. group in determining the reasonableness of its position. If management determines that future income generated by the U.K. group is insufficient to cause the realization of the net operating losses within a reasonable period, a valuation allowance would be required for the U.K. portion of the deferred tax asset balance related to net operating losses in the amount of $1.9 million.
Management believes it is more likely than not that the tax benefit of the remaining net deferred tax assets will be realized.
Shareholders’ equity at December 31, 2014 and 2013 reflected tax benefits of $4.0 million and $1.8 million, respectively, related to the excess of tax deductions over book compensation expense for stock awards exercised/vested by the Company's U.S. subsidiaries.
At December 31, 2014 and 2013, the Company had unrecognized tax benefits of $37.2 million and $30.0 million, respectively. If recognized, the full amount of these unrecognized tax benefits would decrease the annual effective tax rate. The Company does not currently anticipate any significant change in unrealized tax benefits during 2015.
The following table presents a reconciliation of the Company’s unrecognized tax benefits:


(U.S. dollars in thousands)	2014				2013
Unrecognized tax benefits, beginning of the year	$	30,000			$	—

Increases for tax positions taken during the year	12,182				9,591

Increases for tax positions taken in prior years	15,304				20,409

Decreases for tax positions taken during the year	—				—

Decreases for tax positions taken in prior years	(20,296		)		—

Decreases for settlement with taxing authorities	—				—

Decreases for lapse of the applicable statute of limitations	—				—

Unrecognized tax benefits, end of year	$	37,190			$	30,000

The Company’s policy is to recognize any interest and penalties accrued related to unrecognized tax benefits in the tax charge. At December 31, 2014 and 2013, the Company had accrued interest and penalties of $0.4 million and $1.0 million, respectively.

Statutory_Financial_Data

Statutory Financial Data	12 Months Ended
Statutory Financial Data	Dec. 31, 2014
Statutory Capital And Surplus Disclosure Text Block [Abstract]
Statutory financial data	Statutory Financial Data
	The Company’s ability to pay dividends or return capital from shareholders’ equity is limited by applicable laws and regulations of the various jurisdictions in which the Company’s principal operating subsidiaries operate, certain additional required regulatory approvals and financial covenants contained in the Company’s letters of credit and revolving credit facilities. The payment of dividends to XL-Ireland and XL-Cayman, the Company’s holding companies, by the Company’s principal operating subsidiaries is regulated under the laws of various jurisdictions including Bermuda, the U.K., Ireland and Switzerland and certain insurance statutes of various states in the United States in which the principal operating subsidiaries are licensed to transact business and the other jurisdictions where the Company has regulated subsidiaries. Statutory capital and surplus for the principal operating subsidiaries of the Company for the years ended December 31, 2014 and 2013 are summarized below:


	(U.S. dollars in thousands)	Bermuda (1)				U.S. (2)				U.K., Europe and Other
	(U.S. dollars in thousands)	2014		2013		2014		2013		2014		2013
	Required statutory capital and surplus	$	6,194,832	$	6,583,273	$	668,794	$	657,865	$	1,604,721	$	1,970,909
	Required statutory capital and surplus	$	6,194,832	$	6,583,273	$	668,794	$	657,865	$	1,604,721	$	1,970,909
	Actual statutory capital and surplus (3)	$	10,309,895	$	10,168,744	$	2,233,596	$	2,244,505	$	2,712,552	$	2,684,317
	Actual statutory capital and surplus (3)	$	10,309,895	$	10,168,744	$	2,233,596	$	2,244,505	$	2,712,552	$	2,684,317
	____________

	-1	Required statutory capital and surplus at December 31, 2014 represents 100% Bermuda Solvency Capital Requirement (“BSCR”) level for the top Bermuda operating subsidiary, XL Insurance (Bermuda) Ltd, calculated on a consolidated basis (and therefore includes a BSCR requirement for all regions).

	-2	Required statutory capital and surplus represents 100% Risk-Based Capital level for principal U.S. operating subsidiaries.

	-3	Statutory assets in Bermuda include investments in other U.S. and international subsidiaries reported separately herein.
	Statutory net income (loss) for the principal operating subsidiaries of the Company for the years ended December 31, 2014, 2013 and 2012 is summarized below:


	(U.S. dollars in thousands)	2014		2013		2012
	Bermuda	$	361,033	$	1,241,878	$	857,832
	Bermuda	$	361,033	$	1,241,878	$	857,832
	U.S.	$	155,751	$	124,310	$	106,510
	U.S.	$	155,751	$	124,310	$	106,510
	U.K., Europe and Other	$	215,787	$	1,465	$	144,829
	U.K., Europe and Other	$	215,787	$	1,465	$	144,829
	The difference between statutory financial statements and statements prepared in accordance with GAAP varies by jurisdiction, however, the primary difference is that statutory financial statements do not reflect deferred policy acquisition costs, deferred income tax net assets, intangible assets, or unrealized appreciation on investments, but they do reflect any unauthorized/authorized reinsurance charges.
	Certain restrictions on the payment of dividends from retained earnings by the Company’s principal operating subsidiaries are further detailed below.
	Management has evaluated the principal operating subsidiaries’ ability to maintain adequate levels of statutory capital, liquidity and rating agency capital and believes they will be able to do so. In performing this analysis, management has considered the most recent statutory capital position of each of the principal operating subsidiaries as well as the ability of the holding companies to allocate capital and liquidity around the group as and when needed.
	Bermuda Operations
	In early July 2008, the Insurance Amendment Act of 2008 was passed, which introduced a number of changes to the Bermuda Insurance Act 1978, such as allowing the Bermuda Monetary Authority (BMA) to prescribe standards for an enhanced capital requirement and a capital and solvency return with which insurers and reinsurers must comply. The BSCR employs a standard mathematical model that can relate more accurately the risks undertaken by (re)insurers to the capital that is dedicated to their business. Insurers and reinsurers may adopt the BSCR model or, where an insurer or reinsurer believes that its own internal model better reflects the inherent risk of its business, an in-house model approved by the BMA. Class 4 (re)insurers, such as the Company, were required to implement the new capital requirements under the BSCR model beginning with fiscal years ending on or after December 31, 2009. The Company’s capital requirements for its Bermuda principal operating subsidiaries, XL Re Ltd and XL Insurance (Bermuda) Ltd, under the BSCR are highlighted in the table above. In addition to the BSCR based requirements, the BMA also prescribes minimum liquidity standards which must be met.
	Under the Insurance Act 1978, amendments thereto and related regulations of Bermuda, Class 4 (re)insurers are prohibited from declaring or paying dividends of more than 25% of each of their prior year’s statutory capital and surplus unless they file with the BMA an affidavit stating that the dividend has not caused the Class 4 (re)insurer to fail to meet its relevant margins. At December 31, 2014 and 2013, the maximum dividend that our Bermuda Class 4 (re)insurers could pay, without a signed affidavit, having met minimum levels of statutory capital and surplus and liquidity requirements, was approximately $1.4 billion and $1.4 billion, respectively. No Class 4 (re)insurer may reduce its total statutory capital by 15% or more unless it has received the prior approval of the BMA, and it must also submit an affidavit stating that the proposed reduction will not cause it to fail to meet its minimum solvency margin or minimum liquidity ratio.
	U.S. Operations
	Unless permitted by the New York Superintendent of Insurance, the Company’s lead property and casualty subsidiary in the United States (“XLRA”) cannot declare or distribute any dividend to shareholders during any twelve month period that exceeds the lesser of 10 percent of XLRA’s statutory policyholders’ surplus or 100 percent of its “adjusted net investment income,” as defined. The New York State insurance law also provides that any distribution that is a dividend may only be paid out of statutory earned surplus. At December 31, 2014 and 2013, XLRA had statutory earned surplus of $205.5 million and $180.5 million, respectively. At December 31, 2014, XLRA’s statutory policyholders’ surplus was $2.2 billion, and the maximum amount of dividends XLRA can declare and pay in 2015, without prior regulatory approval, is $196.2 million. At December 31, 2014 and 2013, none of the seven property and casualty subsidiaries of XLRA had a statutory earned deficit.
	International Operations
	The Company’s international principal operating subsidiaries prepare statutory financial statements based on local laws and regulations. Some jurisdictions impose enhanced regulatory requirements on insurance companies while other jurisdictions impose fewer requirements. In some countries, such subsidiaries must obtain licenses issued by governmental authorities to conduct local insurance business. These licenses may be subject to minimum reserves and minimum capital and solvency tests. Jurisdictions may impose fines, censure, and/or impose criminal sanctions for violation of regulatory requirements. The majority of the actual statutory capital outside of the U.S. and Bermuda is held in Ireland ($1.1 billion at December 31, 2014) and the U.K. ($1.2 billion at December 31, 2014). The Company’s Irish operating subsidiary, XL Re Europe SE, is required to seek prior approval from the Irish regulator to reduce its share capital or to pay dividends.
	Other Restrictions
	XL-Ireland and XL-Cayman have no operations of their own and their assets consist primarily of investments in subsidiaries. Accordingly, XL-Ireland’s and XL-Cayman’s future cash flows largely depend on the availability of dividends or other permissible payments from subsidiaries as noted above.
	XL-Ireland is subject to certain legal constraints that affect its ability to pay dividends on or redeem or buyback its ordinary shares. While XL-Ireland’s Articles of Association authorize its board of directors to declare and pay dividends as justified from the profits, under Irish law, XL-Ireland may only pay dividends or buyback or redeem shares using distributable reserves. In addition, no dividend or distribution may be made unless the net assets of XL-Ireland are not less than the aggregate of its share capital plus undistributable reserves and the distribution does not reduce XL-Ireland’s net assets below such aggregate. At December 31, 2014, XL-Ireland had $2.9 billion in distributable reserves.
	In addition, XL-Cayman is subject to certain constraints that affect its ability to pay dividends on its preferred shares. Under Cayman Islands law, XL-Cayman may not declare or pay a dividend if there are reasonable grounds for believing that XL-Cayman is, or would after the payment be, unable to pay its liabilities as they become due in the ordinary course of business. Also, the terms of XL-Cayman’s preferred shares prohibit declaring or paying dividends on the ordinary shares unless full dividends have been declared and paid on the outstanding preferred shares. Full dividends have been declared and paid on the outstanding preferred shares at December 31, 2014.
	At December 31, 2014, XL-Ireland and XL-Cayman held cash and investments, net of liabilities associated with cash sweeping arrangements, of $22.4 million and $0.9 billion, respectively, compared to $12.7 million and $1.6 billion, respectively, at December 31, 2013.
	The ability to declare and pay dividends may also be restricted by financial covenants in the Company’s letters of credit and revolving credit facilities. The Company was in compliance with all covenants by significant margins at December 31, 2014, and the Company currently remains in compliance.

Computation_of_Earnings_Per_Or

Computation of Earnings Per Ordinary Share and Ordinary Share Equivalent	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Computation of earnings per ordinary share and ordinary share equivalent	Computation of Earnings Per Ordinary Share and Ordinary Share Equivalent
	The following table sets forth the computation of basic and diluted earnings per ordinary share for the years ended December 31, 2014, 2013 and 2012:


	(U.S. dollars in thousands, except per share amounts)	2014		2013		2012
	Basic earnings per ordinary share and ordinary share equivalents outstanding:
	Net income (loss) attributable to ordinary shareholders	$	188,340	$	1,059,916	$	651,128

	Weighted average ordinary shares outstanding	267,103		287,801		307,372

	Basic earnings per ordinary share and ordinary share equivalents outstanding	$	0.71	$	3.68	$	2.12


	Diluted earnings per ordinary share and ordinary share equivalents outstanding:
	Weighted average ordinary shares outstanding – basic	267,103		287,801		307,372

	Impact of share based compensation and certain conversion features	4,424		4,268		2,910

	Weighted average ordinary shares outstanding – diluted	271,527		292,069		310,282

	Diluted earnings per ordinary share & ordinary share equivalents outstanding	$	0.69	$	3.63	$	2.1

	Dividends per ordinary share	$	0.64	$	0.56	$	0.44

	For the years ended December 31, 2014, 2013 and 2012, ordinary shares available for issuance under share-based compensation plans of 5.5 million, 6.0 million and 8.7 million, respectively, were not included in the calculation of diluted earnings per share because the assumed exercise or issuance of such shares would be anti-dilutive.

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related party transactions	Related Party Transactions
	At December 31, 2014 and 2013, the Company owned minority stakes in six and five, respectively, independent investment management companies (“Investment Manager Affiliates”) that are actively managing client capital and seeking growth opportunities. The Company seeks to develop relationships with specialty investment management organizations, generally acquiring an equity interest in the business. The Company also invests in certain of the funds and limited partnerships and other legal entities managed by these affiliates and through these funds and partnerships pays management and performance fees to the Company's Investment Manager Affiliates. See Note 7, "Investment in Affiliates,” included herein, for further information.
	In the normal course of business, the Company enters into reinsurance contracts with certain of its other strategic affiliates, or their subsidiaries. During the years ended December 31, 2014, 2013 and 2012, these contracts resulted in reported net premiums written, net reported claims and reported acquisition costs as summarized below. Management believes that these transactions are conducted at market rates consistent with negotiated arms-length contracts.


	(U.S. dollars in thousands)	2014		2013		2012
	Reported net premiums written	$	91,261	$	73,085	$	61,146

	Net losses incurred	$	38,927	$	29,042	$	37,664

	Reported acquisition costs	$	35,711	$	25,275	$	24,014


	Several of the Company's wholly-owned subsidiaries retrocede assumed reinsurance business to special purpose reinsurers that receive capital funds managed by New Ocean, which is discussed in Note 18, "Variable Interest Entities." Underwriting administration services are provided to the special purpose reinsurers by other subsidiaries of the Company under service fee agreements negotiated at arm's length, while investment advisory services are provided by New Ocean.

Unaudited_Quarterly_Financial_

Unaudited Quarterly Financial Data	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Unaudited quarterly financial data	Unaudited Quarterly Financial Data
	The following is a summary of the unaudited quarterly financial data for 2014 and 2013:


	(U.S. dollars in thousands, except per share amounts)	First		Second			Third		Fourth
		Quarter		Quarter			Quarter		Quarter
	2014
	Net premiums earned – P&C operations	$	1,412,528	$	1,438,076		$	1,453,673	$	1,413,161

	Net premiums earned – Corporate and Other	$	76,311	$	58,518		$	19,739	$	23,064

	Underwriting profit (loss) – P&C operations	$	144,874	$	167,946		$	144,375	$	218,851

	Net income (loss) attributable to ordinary shareholders	$	255,717	$	(279,261	)	$	72,384	$	139,500

	Net income (loss) per ordinary share and ordinary equivalent – basic	$	0.93	$	(1.03	)	$	0.27	$	0.54

	Net income (loss) per ordinary share and ordinary equivalent – diluted	$	0.91	$	(1.03	)	$	0.27	$	0.53

	2013
	Net premiums earned – P&C operations	$	1,464,246	$	1,488,497		$	1,550,629	$	1,510,727

	Net premiums earned – Corporate and Other	$	65,445	$	73,896		$	74,683	$	81,398

	Underwriting profit (loss) – P&C operations	$	180,588	$	92,124		$	76,900	$	101,450

	Net income (loss) attributable to ordinary shareholders	$	350,790	$	272,698		$	135,648	$	300,780

	Net income (loss) per ordinary share and ordinary equivalent – basic	$	1.19	$	0.94		$	0.48	$	1.07

	Net income (loss) per ordinary share and ordinary equivalent – diluted	$	1.17	$	0.93		$	0.47	$	1.05

Subsequent_Events_Notes

Subsequent Events (Notes)	12 Months Ended
Subsequent Events (Notes)	Dec. 31, 2014
Subsequent Event [Line Items]
Subsequent Events [Text Block]	Subsequent Events
	Catlin Acquisition
	On January 9, 2015, the Company entered into an implementation agreement (the “Implementation Agreement”) with Catlin Group Limited (“Catlin”) and Green Holdings Limited, a direct, wholly-owned subsidiary of the Company (“Green Holdings”), pursuant to which the Company will acquire the entire issued and to be issued share capital of Catlin (the “Acquisition”) for cash and newly-issued ordinary shares of the Company. The Acquisition is intended to be effected by means of a two-step, integrated process comprising a scheme of arrangement (the “Scheme”) under Section 99 of the Companies Act 1981 Bermuda, as amended (the “Companies Act”), which is required to be sanctioned by the Supreme Court of Bermuda, followed immediately by a merger of Catlin with and into Green Holdings under Section 104H of the Companies Act. In certain circumstances set forth in the Implementation Agreement, the Acquisition may alternatively be effected by means of a takeover offer or by a single-step merger of Catlin with and into Green Holdings under the Companies Act. Under the terms of the Acquisition, Catlin shareholders will be entitled to receive 388 pence in cash and 0.130 ordinary shares of the Company, in exchange for each Catlin common share, par value $0.01 per share (“Catlin Shares”), subject to the proration and adjustment mechanisms set forth in the Implementation Agreement. On the basis of the closing price of an ordinary share of the Company on January 8, 2015 of $35.42, the Acquisition values Catlin at 693 pence per Catlin Share, representing a transaction equity value of approximately $4.1 billion. It is intended that the newly-issued ordinary shares of the Company will be listed on the New York Stock Exchange following the completion of the Acquisition. For further information on the Acquisition, see the Company’s Report on Form 8-K filed with the U.S. Securities Exchange Commission (the “SEC”) under Items 1.01, 2.03. 3.02, 8.01 and 9.01 on January 9, 2015.
	In connection with the Acquisition, on January 9, 2015, the Company, Green Holdings and Catlin entered into a Merger Agreement (the “Merger Agreement”), which provides for the merger of Catlin with and into Green Holdings pursuant to Section 104H of the Bermuda Companies Act, with Green Holdings continuing as the surviving company (the “Merger”). If the Implementation Agreement is terminated, or if the Company publicly announces that the Acquisition will be implemented by another means in accordance with the Implementation Agreement, the Merger Agreement will terminate. The parties’ respective boards of directors have approved the Merger and the Merger Agreement. The Company, as sole shareholder of Green Holdings, has approved the Merger and the Merger Agreement, and immediately following effectiveness of the Scheme, XL, as sole shareholder of Catlin, will approve the Merger and the Merger Agreement. The Scheme and the Merger are intended to be a single, integrated transaction that qualifies as a reorganization for U.S. federal income tax purposes.
	On January 9, 2015, the Company entered into contingent deliverable foreign exchange forwards with Morgan Stanley Capital Services LLC and Goldman Sachs International. The purpose of these transactions is to mitigate risk of foreign currency exposure related to the pending Acquisition and in general, these transactions will terminate without any payments due by any of the parties if the Acquisition does not close on or before October 9, 2015.
	On January 9, in connection with the Acquisition, XL-Cayman, as borrower, XL-Ireland, X.L. America, Inc., XL Insurance (Bermuda) Ltd, XL Re Ltd, and XL Life Ltd, as guarantors, Morgan Stanley Senior Funding, Inc., as administrative agent, and the lenders party thereto entered into a senior unsecured 364-Day Bridge Loan Agreement (the “Bridge Loan Agreement”) providing for a £1.6 billion bridge loan facility (the “Bridge Facility”). The proceeds of the Bridge Facility may be used to finance the payment of the cash consideration in connection with the Acquisition and to pay fees and expenses related thereto. The Bridge Loan Agreement contains financial covenants that require the Company to maintain a minimum consolidated net worth and a maximum ratio of total consolidated debt to the sum of total consolidated debt plus consolidated net worth, and that require each of XL Insurance (Bermuda) Ltd, XL Re Ltd and XL Re Europe SE to maintain a financial strength rating of no less than “A-” from A.M. Best & Co. The terms of the Bridge Facility also include customary affirmative covenants, negative covenants and events of default similar to those under our Syndicated Credit Agreement with additional covenants related to the Acquisition and mandatory commitment reduction and loan prepayment provisions in connection with asset sales and debt and equity issuances. If an event of default under the Bridge Loan Agreement shall occur and be continuing, the maturity of such loans (to the extent funded) and all other obligations of XL-Cayman under the Bridge Loan Agreement may be accelerated and all commitments terminated. For further information on the Bridge Facility, see the Company’s Report on Form 8-K filed with the SEC on January 9, 2015 under Items 1.01, 2.03, 8.01 and 9.01.
	Sale of Strategic Operating Affiliate
	On December 15, 2014, XL Re Ltd ("XL Re"), an indirect wholly-owned subsidiary of the Company, and other shareholders of ARX entered into a Stock Purchase Agreement with Progressive to sell all of its shares in ARX to Progressive. XL Re's shares in ARX represented approximately 40% of ARX's outstanding capital stock on a fully diluted basis at the time of the announcement. At December 31, 2014, the Company recorded XL Re's shares in ARX as $204.4 million, included within Investments in Affiliates.
	The transaction is expected to close in the second quarter of 2015 and is subject to regulatory approvals and satisfaction of other closing conditions. XL Re anticipates proceeds of approximately $500 million related to the sale, which will be based upon the consolidated tangible net book value of ARX and its subsidiaries at December 31, 2014, and certain other factors.

Schedule_I_Consolidated_Summar

Schedule I - Consolidated Summary of Investments - other than Investments in Related Parties	12 Months Ended
	Dec. 31, 2014
Summary of Investments, Other than Investments in Related Parties [Abstract]
Schedule I - Consolidated summary of investments - other than investments in related parties	SCHEDULE I
	CONSOLIDATED SUMMARY OF INVESTMENTS – OTHER THAN
	INVESTMENTS IN RELATED PARTIES
	AT DECEMBER 31, 2014 AND 2013


		2014									2013
	(U.S. dollars in thousands)	Cost or			Fair			Amount Presented in the Balance Sheet			Cost or			Fair			Amount Presented in the Balance Sheet
		Amortized			Value						Amortized			Value
		Cost (1)									Cost (1)
	Fixed Maturities – AFS - Excluding Life Funds Withheld Assets:
	U.S. Government and Government	$	2,100,851		$	2,171,953		$	2,171,953		$	2,484,193		$	2,501,851		$	2,501,851
	Agency-Related/Supported
	Corporate	8,462,130			8,778,373			8,778,373			10,802,332			11,125,830			11,125,830

	RMBS – Agency	3,625,171			3,728,576			3,728,576			3,540,101			3,546,122			3,546,122

	RMBS – Non-Agency	404,398			427,351			427,351			396,798			398,768			398,768

	CMBS	1,033,819			1,052,544			1,052,544			1,223,313			1,246,795			1,246,795

	CDO	717,544			692,034			692,034			754,414			717,313			717,313

	Other asset-backed securities	1,028,528			1,065,293			1,065,293			1,210,384			1,242,104			1,242,104

	U.S. States and political subdivisions of the States	1,892,566			2,021,272			2,021,272			1,821,499			1,845,812			1,845,812

	Non-U.S. Sovereign Government, Supranational and Government-Related	4,162,425			4,240,073			4,240,073			4,878,840			4,875,541			4,875,541

	Total Fixed maturities – AFS	$	23,427,432		$	24,177,469		$	24,177,469		$	27,111,874		$	27,500,136		$	27,500,136

	Equity securities	763,833			868,292			868,292			903,201			1,040,237			1,040,237

	Short-term investments	257,221			256,727			256,727			455,470			456,288			456,288

	Total Investments - AFS - Excluding Life Funds Withheld Assets	24,448,486			25,302,488			25,302,488			28,470,545			28,996,661			28,996,661

	Fixed Maturities - AFS - Life Funds Withheld Assets
	U.S. Government and Government agency-Related/Supported	14,866			18,724			18,724			—			—			—

	Corporate	2,407,849			2,817,980			2,817,980			—			—			—

	RMBS – Agency	3,301			3,782			3,782			—			—			—

	RMBS – Non-Agency	71,075			85,335			85,335			—			—			—

	CMBS	168,886			193,167			193,167			—			—			—

	Other asset-backed securities	238,168			273,541			273,541			—			—			—

	Non-U.S. Sovereign Government, Supranational and Government-Related	1,397,194			1,789,036			1,789,036			—			—			—

	Total Fixed maturities - AFS - Life Funds Withheld Assets	4,301,339			5,181,565			5,181,565			—			—			—

	Total Investments - AFS	28,749,825			30,484,053			30,484,053			28,470,545			28,996,661			28,996,661

	Fixed maturities – HTM	—			—			—			2,858,695			3,131,235			2,858,695

	Fixed maturities - Trading
	Corporate	1,180			1,171			1,171			—			—			—

	Total investments - Trading	1,180			1,171			1,171			—			—			—

	Other investments	1,002,871			1,248,439			1,248,439			949,310			1,167,382			1,164,630

Total investments other than investments in related parties	$	29,753,876		$	31,733,663		$	31,733,663		$	32,278,550		$	33,295,278		$	33,019,986

____________

-1	Investments in fixed maturities, short-term investments and held to maturity are shown at amortized cost.

Schedule_II_Condensed_Financia

Schedule II - Condensed Financial Information of Registrant	12 Months Ended
	Dec. 31, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Schedule II - Condensed financial information of registrant	SCHEDULE II
	CONDENSED FINANCIAL INFORMATION OF REGISTRANT
	CONDENSED BALANCE SHEETS – PARENT COMPANY ONLY
	AT DECEMBER 31, 2014 AND 2013


	(U.S. dollars in thousands)	2014				2013
	ASSETS
	Cash and cash equivalents	$	22,443			$	12,709

	Investments in subsidiaries on an equity basis	10,195,445				10,187,614

	Other assets	3,017				3,014

	Total assets	$	10,220,905			$	10,203,337

	LIABILITIES AND SHAREHOLDERS’ EQUITY
	Liabilities:
	Amounts due to subsidiaries	$	166,782			$	190,601

	Accounts payable and accrued liabilities	20,371				15,103

	Total liabilities	$	187,153			$	205,704

	Commitments and Contingencies

	Shareholders’ Equity:
	Ordinary shares, 999,990,000 authorized, par value $0.01; issued and outstanding: (2014: 255,182,955; 2013: 278,253,308)	$	2,552			$	2,783

	Additional paid in capital	7,359,102				7,994,100

	Accumulated other comprehensive income	1,484,458				736,657

	Retained earnings (deficit)	1,187,640				1,264,093

	Total shareholders’ equity	$	10,033,752			$	9,997,633

	Total liabilities and shareholders’ equity	$	10,220,905			$	10,203,337

	See accompanying Notes to Condensed Financial Information of Registrant


	XL GROUP PLC
	SCHEDULE II
	CONDENSED FINANCIAL INFORMATION OF REGISTRANT
	STATEMENT OF INCOME AND COMPREHENSIVE INCOME – PARENT COMPANY ONLY
	FOR THE YEARS ENDED DECEMBER 31, 2014, 2013 AND 2012


	(U.S. dollars in thousands)	2014				2013				2012
	Net investment income	$	275			$	24			$	5

	Total revenues	$	275			$	24			$	5

	Operating expenses	$	9,646			$	11,699			$	10,971

	Foreign exchange (gains) losses	127				243				165

	Interest expense	5				2				15

	Total expenses	$	9,778			$	11,944			$	11,151

	Income (loss) before income tax	$	(9,503	)		$	(11,920	)		$	(11,146	)
	Equity in net earnings (losses) of subsidiaries (dividends were: 2014: $858,521; 2013: $617,719; 2012: nil)	197,843				1,071,836				662,274

Net income (loss) attributable to ordinary shareholders	$	188,340			$	1,059,916			$	651,128

Net income (loss)	$	188,340			$	1,059,916			$	651,128

Change in net unrealized gains (losses) on investments - excluding Life Funds Withheld Assets, net of tax	434,051				(750,755		)		834,601

Unrealized gains on held to maturity investment portfolio at time of transfer to available for sale, net of tax	424,861				—				—

Change in adjustments related to future policy benefit reserves, net of tax	(400,456		)		(44,660		)		—

Change in net unrealized gains (losses) on investments - Life Funds Withheld Assets, net of tax	274,083				—				—

Change in net unrealized gains (losses) on affiliate and investments, net of tax	35,143				26,637				46,162

Change in OTTI losses recognized in other comprehensive income, net of tax	13,143				32,181				67,280

Change in underfunded pension liability	(7,550		)		7,653				(3,371		)

Change in value of cash flow hedge	255				439				439

Foreign currency translation adjustments	(25,729		)		(54,858		)		(8,156		)
Comprehensive income (loss)	$	936,141			$	276,553			$	1,588,083

See accompanying Notes to Condensed Financial Information of Registrant

XL GROUP PLC
SCHEDULE II
CONDENSED FINANCIAL INFORMATION OF REGISTRANT
STATEMENT OF CASH FLOWS – PARENT COMPANY ONLY
FOR THE YEARS ENDED DECEMBER 31, 2014, 2013 AND 2012


(U.S. dollars in thousands)	2014				2013				2012
Net income (loss)	$	188,340			$	1,059,916			$	651,128

Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity in (earnings) loss of subsidiaries	(197,843		)		(1,071,836		)		(662,274		)
Share based compensation	81,287				46,489				47,472

Amounts due to (from) subsidiaries	(23,819		)		104,590				166,853

Dividends received from subsidiaries	858,521				617,719				—

Other	(10,632		)		(16,570		)		(3,296		)
Total adjustments	$	707,514			$	(319,608	)		$	(451,245	)

Net cash provided by (used in) operating activities	$	895,854			$	740,308			$	199,883

Cash flows provided by (used in) investing activities:
Returns of capital from subsidiaries	$	79,086			$	84,589			$	341,750

Net cash provided by (used in) investing activities	$	79,086			$	84,589			$	341,750

Cash flows provided by (used in) financing activities:
Proceeds from issuance of ordinary shares and exercise of stock options	$	6,367			$	12,623			$	5,413

Dividends paid	(169,620		)		(160,155		)		(134,799		)
Buybacks of ordinary shares	(801,953		)		(675,617		)		(402,930		)
Net cash provided by (used in) financing activities	$	(965,206	)		$	(823,149	)		$	(532,316	)
Net change in cash and cash equivalents	9,734				1,748				9,317

Cash and cash equivalents – beginning of period	12,709				10,961				1,644

Cash and cash equivalents – end of period	$	22,443			$	12,709			$	10,961

See accompanying Notes to Condensed Financial Information of Registrant

XL GROUP PLC
SCHEDULE II
CONDENSED FINANCIAL INFORMATION OF REGISTRANT
NOTES TO THE FINANCIAL STATEMENTS - PARENT COMPANY ONLY
FOR THE YEARS ENDED DECEMBER 31, 2014, 2013 AND 2012

1. Presentation
The condensed financial information of XL Group plc reflects its directly wholly-owned subsidiaries using the equity method of accounting. To facilitate period-to-period comparisons, certain reclassifications have been made to prior year condensed financial statement amounts to conform to the current year presentation. There has been no effect on net income from this change in presentation.
2. Dividends and Returns of Capital
For the indicated years ended December 31, XL Group plc received dividends and/or returns of capital from XLIT Ltd. a wholly-owned subsidiary.


(U.S. dollars in million)	2014				2013				2012
Dividends and returns of capital	$	940			$	702			$	342

3. Commitments and Guarantees
See Item 8, Note 19, “Commitments and Contingencies,” to the Consolidated Financial Statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2014.

Schedule_IV_Reinsurance

Schedule IV - Reinsurance	12 Months Ended
	Dec. 31, 2014
Supplemental Schedule of Reinsurance Premiums for Insurance Companies [Abstract]
Schedule IV - Reinsurance	SCHEDULE IV
	REINSURANCE
	FOR THE YEARS ENDED DECEMBER 31, 2014, 2013 AND 2012


	(U.S. dollars in thousands)	Gross		Ceded		Assumed		Net		Percentage
		Amount		to Other		from Other		Amount		of Amount
				Companies		Companies				Assumed
										to Net
	2014
	Life reinsurance in force (1)	$	—	$	46,947,677	$	68,854,340	$	21,906,663	314.3	%

	Premiums Earned:
	Property and casualty operations	$	5,173,403	$	1,799,294	$	2,343,329	$	5,717,438	41	%

	Life operations	—		155,804		333,436		177,632		187.7	%

	Total premiums earned	$	5,173,403	$	1,955,098	$	2,676,765	$	5,895,070	45.4	%

	2013
	Life reinsurance in force (1)	$	—	$	378,391	$	77,917,632	$	77,539,241	100.5	%

	Premiums Earned:
	Property and casualty operations	$	4,966,207	$	1,315,369	$	2,363,261	$	6,014,099	39.3	%

	Life operations	—		28,920		324,342		295,422		109.8	%

	Total premiums earned	$	4,966,207	$	1,344,289	$	2,687,603	$	6,309,521	42.6	%

	2012
	Life reinsurance in force (1)	$	—	$	443,798	$	82,099,647	$	81,655,849	100.5	%

	Premiums Earned:
	Property and casualty operations	$	4,604,323	$	1,231,835	$	2,393,490	$	5,765,978	41.5	%

	Life operations	—		31,322		355,781		324,459		109.7	%

	Total premiums earned	$	4,604,323	$	1,263,157	$	2,749,271	$	6,090,437	45.1	%

	____________

	-1	Represents the sum face value outstanding of the in force life reinsurance policies.

Schedule_VI_Supplementary_Info

Schedule VI - Supplementary Information Concerning Property/Casualty Insurance Operations	12 Months Ended
	Dec. 31, 2014
Supplemental Information for Property, Casualty Insurance Underwriters [Abstract]
Schedule VI - Supplementary information concerning property/casualty (re)insurance operations	SCHEDULE VI
	SUPPLEMENTAL INFORMATION
	CONCERNING PROPERTY/CASUALTY (RE)INSURANCE OPERATIONS
	FOR THE YEARS ENDED DECEMBER 31, 2014, 2013 AND 2012



	(U.S. dollars	Deferred		Reserves		Reserves		Net		Net		Losses and Loss					Net Paid		Amortization		Net
	in thousands)	Acquisition		for		for		Earned		Investment		Expenses					Losses		of Deferred		Premiums
		Costs		Losses		Unearned		Premiums		Income		incurred related to					and		Acquisition		Written
				and Loss		Premiums											Loss		Costs
				Expenses								Current		Prior			Expenses
												Year		Year
	2014	$	357,067	$	19,353,241	$	3,973,159	$	5,717,438	$	642,492	$	3,513,469	$	(255,076	)	$	3,821,335	$	724,003	$	5,767,209

	2013	$	537,473	$	20,481,065	$	3,846,568	$	6,014,099	$	671,071	$	4,021,353	$	(289,889	)	$	3,828,139	$	882,658	$	5,903,982

	2012	$	536,664	$	20,484,121	$	3,755,117	$	5,765,978	$	712,905	$	4,081,376	$	(315,894	)	$	3,783,242	$	872,399	$	5,957,019

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of preparation	These consolidated financial statements include the accounts of the Company and all of its subsidiaries. These consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). To facilitate period-to-period comparisons, certain reclassifications have been made to prior year consolidated financial statement amounts to conform to the current year presentation. There was no effect on net income from this change in presentation.
Use of estimates	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The Company’s most significant areas of estimation include:

	▪	unpaid losses and loss expenses and unpaid losses and loss expenses recoverable;

	▪	future policy benefit reserves;

	▪	valuation and other-than-temporary impairments of investments;

	▪	income taxes;

	▪	reinsurance premium estimates; and

	▪	goodwill carrying value.
	While management believes that the amounts included in the consolidated financial statements reflect the Company’s best estimates and assumptions, actual results could differ from these estimates.
Basis of fair value measurement	Financial Instruments Subject to Fair Value Measurements
	Accounting guidance over fair value measurements requires that a fair value measurement reflect the assumptions market participants would use in pricing an asset or liability based on the best information available. Assumptions include the risks inherent in a particular valuation technique (such as a pricing model) and/or the risks inherent in the inputs to the model. The fair value of a financial instrument is the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (the “exit price”). Instruments that the Company owns (“long positions”) are marked to bid prices and instruments that the Company has sold but not yet purchased (“short positions”) are marked to offer prices. Fair value measurements are not adjusted for transaction costs.
	Basis of Fair Value Measurement
	Fair value measurements accounting guidance also establishes a fair value hierarchy that prioritizes the inputs to the respective valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). An asset or liability’s classification within the fair value hierarchy is based on the lowest level of significant input to its valuation. The three levels of the fair value hierarchy are described further below:

	▪	Level 1 - Quoted prices in active markets for identical assets or liabilities (unadjusted); no blockage factors.

	▪	Level 2 - Other observable inputs (quoted prices in markets that are not active or inputs that are observable either directly or indirectly)—include quoted prices for similar assets/liabilities (adjusted) other than quoted prices in Level 1; quoted prices in markets that are not active; or other inputs that are observable or can be derived principally from or corroborated by observable market data for substantially the full term of the assets or liabilities.

	▪	Level 3 - Unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets or liabilities. Unobservable inputs reflect the reporting entity’s own assumptions about the assumptions that market participants would use in pricing the asset or liability. Level 3 assets and liabilities include financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation.
	Details on assets and liabilities that have been included under the requirements of authoritative guidance on fair value measurements to illustrate the bases for determining the fair values of these items held by the Company are included in each respective significant accounting policy section of this note.
	Fair values of investments and derivatives are based on published market values if available, estimates of fair values of similar issues, or estimates of fair values provided by independent pricing services and brokers. Fair values of financial instruments for which quoted market prices are not available or for which the company believes current trading conditions represent distressed markets are based on estimates using present value or other valuation techniques. The fair values estimated using such techniques are significantly affected by the assumptions used, including the discount rates and the estimated amounts and timing of future cash flows. In such instances, the derived fair value estimates cannot be substantiated by comparison to independent markets and are not necessarily indicative of the amounts that would be realized in a current market exchange.
Investments	Investments - Available For Sale
	Investments that are considered available for sale (comprised of fixed maturities, equity securities and short-term investments) are carried at fair value. The fair values for available for sale investments are generally sourced from third parties. The fair values of fixed income securities are based upon quoted market values where available, “evaluated bid” prices provided by third party pricing services (“pricing services”) where quoted market values are not available, or by reference to broker or underwriter bid indications where pricing services do not provide coverage for a particular security. To the extent the Company believes current trading conditions represent distressed transactions, the Company may elect to utilize internally generated models.
	It is common industry practice to utilize pricing services as a source for determining the fair values of investments where the pricing services are able to obtain sufficient market corroborating information to allow them to produce a valuation at a reporting date. In addition, in the majority of cases, although a value may be obtained from a particular pricing service for a security or class of similar securities, these values are corroborated against values provided by other pricing services. The pricing services use market approaches to valuations using primarily Level 2 inputs in the vast majority of valuations, or some form of discounted cash flow analysis, to obtain investment values for a small percentage of fixed income securities for which they provide a price. Standard inputs to the valuations provided by the pricing services listed in approximate order of priority for use when available include: reported trades, benchmark yields, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, and reference data. The pricing services may prioritize inputs differently on any given day for any security, and not all inputs listed are available for use in the evaluation process on any given day for each security evaluation; however, the pricing services also monitor market indicators, customer feedback through a price challenge process and industry and economic events. Information of this nature is a trigger to acquire further corroborating market data. When these inputs are not available, they identify “buckets” of similar securities (allocated by asset class types, sectors, sub-sectors, contractual cash flows/structure, and credit rating characteristics) and apply some form of matrix or other modeled pricing to determine an appropriate security value which represents their best estimate as to what a buyer in the marketplace would pay for a security in a current sale. Prices provided by independent pricing services and independent broker quotes can vary widely even for the same security. The use of different methodologies and assumptions may have a material effect on the estimated fair value amounts. While the Company receives values for the majority of the investment securities it holds from pricing services, it is ultimately management’s responsibility to determine whether the values received and recorded in the financial statements are representative of appropriate fair value measurements.
	Broker/dealer quotations are used to value fixed maturities where prices are unavailable from pricing services due to factors specific to the security such as limited liquidity, lack of current transactions, or trades only taking place in privately negotiated transactions. These are considered Level 3 valuations, as significant inputs utilized by brokers may be difficult to corroborate with observable market data, or sufficient information regarding the specific inputs utilized by the broker was not available to support a Level 2 classification.
	Equity securities include investments in open end mutual funds and shares of publicly traded alternative funds. The fair value of equity securities is based upon quoted market values (Level 1), or monthly net asset value statements provided by the investment managers upon which subscriptions and redemptions can be executed (Level 2).
	Short-term investments include investments due to mature within one year from the date of purchase and are valued using the same external factors and in the same manner as fixed income securities.
	Changes in the value of investments available for sale are reflected as unrealized gains or losses on investments, and are included in “accumulated other comprehensive income (loss)", on a net of tax basis.
	All investment transactions are recorded on a trade date basis. Realized gains and losses on sales of equities and fixed income investments are determined on a first-in, first-out basis.
	Investment income is recognized when earned and includes interest and dividend income together with the amortization of premium and discount on fixed maturities and short-term investments, and is recorded net of related investment expenses. Amortization of discounts on fixed maturities includes amortization to expected recovery values for investments that have previously been recorded as other than temporarily impaired. For mortgage-backed securities, and any other holdings for which there is a prepayment risk, prepayment assumptions are evaluated and revised as necessary. Prepayment fees or call premiums that are only payable to the Company when a security is called prior to its maturity are earned when received and reflected in net investment income.
	Investments - Trading
	Investments for which the company has elected the fair value option are classified as trading. Trading securities are carried at fair value with changes included in "Net realized gains (losses) on investments sold." Interest and dividend income from trading securities are included as a component of "Net investment income - Life Funds Withheld Assets" as all trading securities are held in support of the life retrocession arrangements. See Note 3, "Sale of Life Reinsurance Subsidiary," for information regarding the reinsurance arrangement.
	Investments - Held to Maturity
	Investments classified as held to maturity include securities for which the Company has the ability and intent to hold to maturity and are carried at amortized cost. For details see Note 6, “Investments.”
	Investments Related to Life Retrocession Arrangements written on a Funds Withheld Basis
	Designated investments that support the life retrocession arrangements written on a funds withheld basis ("Life Funds Withheld Assets") entered into in connection with the sale of our life reinsurance subsidiary are classified as either available for sale or trading. Investment results for these assets - including interest income, unrealized gains and losses, and gains and losses from sales - are passed directly to the reinsurer pursuant to a contractual arrangement which is accounted for as a derivative. See Note 3, "Sale of Life Reinsurance Subsidiary," for information regarding the reinsurance arrangement.
	Changes in the fair value of the embedded derivative associated with these life retrocession arrangements are recorded in “Net realized and unrealized gains (losses) on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets” on the consolidated statements of income. The fair value of the embedded derivative is included within “Funds withheld on life retrocession arrangements, net of future policy benefit reserves recoverable” on the consolidated balance sheets.
	Investments In Affiliates
	Investments in which the Company has significant influence over the operating and financial policies of the investee are classified as investments in affiliates on the Company’s balance sheets and are accounted for under the equity method of accounting. Under this method, the Company records its proportionate share of income or loss from such investments in its results for the period as well as its portion of movements in certain of the investee shareholders’ equity balances. When financial statements of the affiliate are not available on a timely basis to record the Company’s share of income or loss for the same reporting periods as the Company, the most recently available financial statements are used. This lag in reporting is applied consistently. Distributions received from affiliates representing returns on invested capital are recorded as operating cash flows, while distributions representing returns of invested capital or proceeds upon sale of all or a portion of an affiliate are recorded as investing cash flows.
	The Company generally records its alternative and private investment fund affiliates on a one-month and three-month lag, respectively, and its operating affiliates on a three-month lag. Significant influence is generally deemed to exist where the Company has an investment of 20% or more in the common stock of a corporation or an investment of 3% or more in closed end funds, limited partnerships, LLCs or similar investment vehicles. Significant influence is considered for other strategic investments on a case-by-case basis. Investments in affiliates are not subject to fair value measurement guidance as they are not considered to be fair value measured investments under GAAP. However, impairments associated with investments in affiliates that are deemed to be other-than-temporary are calculated in accordance with fair value measurement guidance and appropriate disclosures included within the financial statements during the period the losses are recorded.
	Other Investments
	Contained within this asset class are equity interests in investment funds, limited partnerships and unrated tranches of collateralized debt obligations for which the Company does not have sufficient rights or ownership interests to follow the equity method of accounting. The Company accounts for equity securities that do not have readily determinable market values at estimated fair value as it has no significant influence over these entities. Also included within other investments are structured transactions, which are carried at amortized cost.
	Fair values for other investments, principally other direct equity investments, investment funds and limited partnerships, are primarily based on the net asset value provided by the investment manager, the general partner or the respective entity, recent financial information, available market data and, in certain cases, management judgment, if required. These entities generally carry their trading positions and investments, the majority of which have underlying securities valued using Level 1 or Level 2 inputs, at fair value as determined by their respective investment managers; accordingly, these investments are generally classified as Level 2. Private equity investments are classified as Level 3. The net unrealized gain or loss on investments, net of tax, is included in “Accumulated other comprehensive income (loss).” Any unrealized loss in value considered by management to be other-than-temporary is charged to income in the period in which it is determined.
	Overseas deposits include investments in private funds related to Lloyd’s syndicates in which the underlying instruments are primarily fixed maturities. The funds themselves do not trade on an exchange and therefore are not included within available for sale securities. Also included in overseas deposits are restricted balances held by Lloyd’s syndicates for solvency purposes which are primarily invested in cash and cash equivalents. Given the restricted nature of these balances, they are included in other investments on the balance sheets. Each of these investment types is considered a Level 2 valuation.
	The Company historically participated in structured transactions that included cash loans supporting project finance transactions and providing liquidity facility financing to a structured project deal in 2009, and the Company also invested in a payment obligation with an insurance company. These transactions are carried at amortized cost.
Premiums	Insurance premiums written are recorded in accordance with the terms of the underlying policies. Reinsurance premiums written are recorded at the inception of the policy and are estimated based upon information received from ceding companies and any subsequent differences arising on such estimates are recorded in the period they are determined. For multi-year reinsurance treaties which are payable in annual installments, generally, only the initial annual installment is included as premiums written at policy inception due to the ability of the reinsured to commute or cancel coverage during the term of the policy. The remaining annual installments are included as premiums written at each successive anniversary date within the multi-year term.
	Premiums are earned on a pro-rata basis over the period the coverage is provided. Unearned premiums represent the portion of premiums written applicable to the unexpired terms of policies in force. Net premiums earned are presented after deductions for reinsurance ceded, as applicable.
	Mandatory reinstatement premiums are recognized and earned at the time a loss event occurs.
	Life and annuity premiums from long duration contracts that transfer significant mortality or morbidity risks are recognized as revenue and earned when due from policyholders. Life and annuity premiums from long duration contracts that do not subject the Company to risks arising from policyholder mortality or morbidity are accounted for as investment contracts and presented within deposit liabilities.
	The Company has periodically written retroactive loss portfolio transfer contracts. These contracts are evaluated to determine whether they meet the established criteria for reinsurance accounting, and, if so, at inception, written premiums are fully earned and corresponding losses and loss expense recognized. The contracts can cause significant variances in gross premiums written, net premiums written, net premiums earned, and net incurred losses in the years in which they are written. Reinsurance contracts sold not meeting the established criteria for reinsurance accounting are recorded using the deposit method.
Acquisition costs	Acquisition costs, which vary with and are directly related to the acquisition of policies, consist primarily of commissions paid to brokers and cedants, and are deferred and amortized over the period during which the premiums are earned. Acquisition costs are shown net of contractual commissions earned on reinsurance ceded. Future earned premiums, the anticipated losses and other costs (and in the case of a premium deficiency, investment income) related to those premiums, are also considered in determining the level of acquisition costs to be deferred.
Reinsurance	In the normal course of business, the Company seeks to reduce the potential amount of loss arising from claims events by reinsuring certain levels of risk assumed in various areas of exposure with other insurers or reinsurers. Reinsurance premiums ceded are expensed (and any commissions recorded thereon are earned) on a monthly pro-rata basis over the period the reinsurance coverage is provided. Ceded unearned reinsurance premiums represent the portion of premiums ceded applicable to the unexpired term of policies in force. Mandatory reinstatement premiums ceded are recorded at the time a loss event occurs. Amounts recoverable from reinsurers are estimated in a manner consistent with the claim liability associated with the reinsured policy. Provisions are made for estimated unrecoverable reinsurance.
	The Company enters into reinsurance agreements with other companies in the normal course of business. All premium and loss-related balances related to reinsurance agreements are reported on a gross basis within our consolidated balance sheets, with the exception of the life retrocession arrangements written on a funds withheld basis. The future policy benefit reserves recoverable related to these retrocession arrangements are netted against the funds withheld liability owing to the counterparty on the consolidated balance sheets due to the contractual right of offset.
Fee income and other	Fee income and other includes fees received for insurance and product structuring services provided and is earned over the service period of the contract. Any adjustments to fees earned or the service period are reflected in income in the period when determined.
Other-than-temporary impairments ("OTTI") of available for sale and held to maturity securities	The Company’s process for identifying declines in the fair value of investments that are other-than-temporary involves consideration of several factors. These primary factors include (i) an analysis of the liquidity, business prospects and financial condition of the issuer including consideration of credit ratings, (ii) the significance of the decline, (iii) an analysis of the collateral structure and other credit support, as applicable, of the securities in question, and (iv) for debt securities, whether the Company intends to sell such securities. In addition, the authoritative guidance requires that OTTI for certain asset backed and mortgage backed securities is recognized if the fair value of the security is less than its discounted cash flow value and there has been a decrease in the present value of the expected cash flows since the last reporting period. Where the Company’s analysis of the above factors results in the Company’s conclusion that declines in fair values are other-than-temporary, the cost of the security is written down to discounted cash flow and a portion of the previously unrealized loss is therefore realized in the period such determination is made.
	If the Company intends to sell an impaired debt security, or it is more likely than not that it will be required to sell the security before recovery of its amortized cost basis, the impairment is other-than-temporary and is recognized currently in earnings in an amount equal to the entire difference between fair value and amortized cost.
	In instances in which the Company determines that a credit loss exists but the Company does not intend to sell the security, and it is not more likely than not that the Company will be required to sell the security before the anticipated recovery of its remaining amortized cost basis, the OTTI is separated into (1) the amount of the total impairment related to the credit loss and (2) the amount of the total impairment related to all other factors (i.e. the noncredit portion). The amount of the total OTTI related to the credit loss is recognized in earnings and the amount of the total OTTI related to all other factors is recognized in accumulated other comprehensive loss. The total OTTI is presented in the income statement with an offset for the amount of the total OTTI that is recognized in accumulated other comprehensive loss. Absent the intent or requirement to sell a security, if a credit loss does not exist, any impairment is considered to be temporary.
	The noncredit portion of any OTTI losses on securities classified as available for sale is recorded as a component of other comprehensive income with an offsetting adjustment to the carrying value of the security. The fair value adjustment could increase or decrease the carrying value of the security. The noncredit portion of any OTTI losses recognized in accumulated other comprehensive loss for debt securities classified as held to maturity would be accreted over the remaining life of the debt security (in a pro rata manner based on the amount of actual cash flows received as a percentage of total estimated cash flows) as an increase in the carrying value of the security until the security is sold, the security matures, or there is an additional OTTI that is recognized in earnings.
	In periods subsequent to the recognition of an OTTI loss, the other-than-temporarily impaired debt security is accounted for as if it had been purchased on the measurement date of the OTTI at an amount equal to the previous amortized cost basis less the credit-related OTTI recognized in earnings. For debt securities for which credit-related OTTI is recognized in earnings, the difference between the new cost basis and the cash flows expected to be collected is accreted into interest income over the remaining life of the security in a prospective manner based on the estimated amount and timing of future estimated cash flows.
	With respect to securities where the decline in value is determined to be temporary and the security’s amortized cost is not written down, a subsequent decision may be made to sell that security and realize a loss. Subsequent decisions on security sales are made within the context of overall risk monitoring, changing information, market conditions generally and assessing value relative to other comparable securities. Day-to-day management of the Company’s investment portfolio is outsourced to third party investment manager service providers. While these investment manager service providers may, at a given point in time, believe that the preferred course of action is to hold securities with unrealized losses that are considered temporary until such losses are recovered, the dynamic nature of the portfolio management may result in a subsequent decision to sell the security and realize the loss, based upon a change in market and other factors described above. The Company believes that subsequent decisions to sell such securities are consistent with the classification of the Company’s portfolio as available for sale.
	There are risks and uncertainties associated with determining whether declines in the fair value of investments are other-than-temporary. These include subsequent significant changes in general economic conditions as well as specific business conditions affecting particular issuers, the Company’s liability profile, subjective assessment of issue-specific factors (seniority of claims, collateral value, etc.), future financial market effects, stability of foreign governments and economies, future rating agency actions and significant disclosure of accounting, fraud or corporate governance issues that may adversely affect certain investments. In addition, significant assumptions and management judgment are involved in determining if the decline is other-than-temporary. If management determines that a decline in fair value is temporary, then a security’s value is not written down at that time. However, there are potential effects upon the Company’s future earnings and financial position should management later conclude that some of the current declines in the fair value of the investments are other-than-temporary declines.
Derivative instruments	The Company recognizes all derivatives as either assets or liabilities in the balance sheets and measures those instruments at fair value. Except for the embedded derivative associated with the life retrocession agreement discussed above within (c) "Investments Related to Life Retrocession Arrangements written on a Funds Withheld Basis", the changes in fair value of derivatives are shown in the consolidated statements of income as “net realized and unrealized gains and losses on derivative instruments,” unless the derivatives are designated as hedging instruments. The accounting for derivatives that are designated as hedging instruments is discussed below. Changes in fair value of derivatives may create volatility in the Company’s results of operations from period to period. Amounts recognized for the right to reclaim cash collateral (a receivable) or the obligation to return cash collateral (a payable) are offset against net fair value amounts recognized in the consolidated balance sheets for derivative instruments executed with the same counterparty under the same netting arrangement to the extent that the Company intends to settle the amounts on a net basis.
	Derivative contracts can be exchange-traded or over-the-counter (“OTC”). Exchange-traded derivatives (futures and options) typically fall within Level 1 of the fair value hierarchy depending on whether they are deemed to be actively traded or not. OTC derivatives are valued using market transactions and other market evidence whenever possible, including market-based inputs to models, model calibration to market clearing transactions, broker or dealer quotations or alternative pricing sources where an understanding of the inputs utilized in arriving at the valuations is obtained. Where models are used, the selection of a particular model to value an OTC derivative depends upon the contractual terms and specific risks inherent in the instrument as well as the availability of pricing information in the market. The Company generally uses similar models to value similar instruments. Valuation models require a variety of inputs, including contractual terms, market prices, yield curves, credit curves, measures of volatility, prepayment rates and correlations of such inputs. For OTC derivatives that trade in liquid markets, such as generic forwards, interest rate swaps and options, model inputs can generally be verified and model selection does not involve significant management judgment. Such instruments comprise the majority of derivatives held by the Company and are typically classified within Level 2 of the fair value hierarchy.
	Certain OTC derivatives trade in less liquid markets with limited pricing information, or required model inputs which are not directly market corroborated, which causes the determination of fair value for these derivatives to be inherently more subjective. Accordingly, such derivatives are classified within Level 3 of the fair value hierarchy. The valuations of less standard or liquid OTC derivatives are typically based on Level 1 and/or Level 2 inputs that can be observed in the market, as well as unobservable Level 3 inputs. Level 1 and Level 2 inputs are regularly updated to reflect observable market changes. Level 3 inputs are only changed when corroborated by evidence such as similar market transactions, pricing services and/or broker or dealer quotations. The Company conducts its non-hedging derivatives activities in three main areas: investment related derivatives, credit derivatives and other non-investment related derivatives.
	The Company uses derivative instruments, primarily interest rate swaps, to manage the interest rate exposure associated with certain assets and liabilities. These derivatives are recorded at fair value. On the date the derivative contract is entered into, the Company may designate the derivative as: a hedge of the fair value of a recognized asset or liability (“fair value” hedge); a hedge of the variability in cash flows of a forecasted transaction or of amounts to be received or paid related to a recognized asset or liability (“cash flow” hedge); or a hedge of a net investment in a foreign operation; or the Company may not designate any hedging relationship for a derivative contract.
	Fair Value Hedges
	Changes in the fair value of a derivative that is designated and qualifies as a fair value hedge, along with the changes in the fair value of the hedged asset or liability that is attributable to the hedged risk, are recorded in current period earnings (through “net realized and unrealized gains and losses on derivative instruments”) with any differences between the net change in fair value of the derivative and the hedged item representing the hedge ineffectiveness. Periodic derivative net coupon settlements are recorded in net investment income with the exception of hedges of Company issued debt, which are recorded in interest expense. The Company may designate fair value hedging relationships where interest rate swaps are used to hedge the changes in fair value of certain fixed rate liabilities and fixed maturity securities due to changes in the designated benchmark interest rate.
	Cash Flow Hedges
	Changes in the fair value of a derivative that is designated and qualifies as a cash flow hedge are recorded in accumulated other comprehensive income (“AOCI”) and are reclassified into earnings when the variability of the cash flow of the hedged item impacts earnings. Gains and losses on derivative contracts that are reclassified from AOCI to current period earnings are included in the line item in the consolidated statements of operations in which the cash flows of the hedged item are recorded. Any hedge ineffectiveness is recorded immediately in current period earnings as “net realized and unrealized gains and losses on derivative instruments.” Periodic derivative net coupon settlements are recorded in net investment income. The Company may designate cash flow hedging relationships where interest rate swaps are used to mitigate interest rate risk associated with anticipated issuances of debt or other forecasted transactions.
	Hedges of the Net Investment in a Foreign Operation
	Changes in fair value of a derivative used as a hedge of a net investment in a foreign operation, to the extent effective as a hedge, are recorded in the foreign currency translation adjustments account within AOCI. Cumulative changes in fair value recorded in AOCI are reclassified into earnings upon the sale or complete or substantially complete liquidation of the foreign entity. Any hedge ineffectiveness is recorded immediately in current period earnings as “net realized and unrealized gains and losses on derivative instruments.”
	Hedge Documentation and Effectiveness Testing
	To qualify for hedge accounting treatment, a derivative must be highly effective in mitigating the designated changes in value or cash flow of the hedged item. At hedge inception, the Company formally documents all relationships between hedging instruments and hedged items, as well as its risk-management objective and strategy for undertaking each hedge transaction. The documentation process includes linking derivatives that are designated as fair value, cash flow, or net investment hedges to specific assets or liabilities on the balance sheets or to specific forecasted transactions. The Company also formally assesses, both at the hedge’s inception and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in fair values or cash flows of hedged items. In addition, certain hedging relationships are considered highly effective if the changes in the fair value or discounted cash flows of the hedging instrument are within a ratio of 80-125% of the inverse changes in the fair value or discounted cash flows of the hedged item. Hedge ineffectiveness is measured using qualitative and quantitative methods. Qualitative methods may include comparison of critical terms of the derivative to the hedged item. Depending on the hedging strategy, quantitative methods may include the “Change in Variable Cash Flows Method,” the “Change in Fair Value Method,” the “Hypothetical Derivative Method” or the “Dollar Offset Method.”
	Discontinuance of Hedge Accounting
	The Company discontinues hedge accounting prospectively when it determines that the derivative is no longer highly effective in offsetting changes in the fair value or cash flows of a hedged item; the derivative is dedesignated as a hedging instrument; or the derivative expires or is sold, terminated or exercised. When hedge accounting is discontinued because it is determined that the derivative no longer qualifies as an effective fair-value hedge, the derivative continues to be carried at fair value on the balance sheets with changes in its fair value recognized in current period earnings through “net realized and unrealized gains and losses on derivative instruments.” When hedge accounting is discontinued because the Company becomes aware that it is not probable that the forecasted transaction will occur, the derivative continues to be carried on the balance sheets at its fair value, and gains and losses that were accumulated in AOCI are recognized immediately in earnings.
Cash equivalents	Cash equivalents include fixed interest deposits placed with a maturity of under 90 days when purchased. Bank deposits are not considered to be fair value measurements and as such are not subject to the authoritative guidance on fair value measurement disclosures. Money market funds are classified as Level 1 as these instruments are considered actively traded; however, certificates of deposit are classified as Level 2.
Foreign currency translation	Assets and liabilities of foreign operations whose functional currency is not the U.S. dollar are translated at prevailing year end exchange rates. Revenue and expenses of such foreign operations are translated at average exchange rates during the year. The net effect of the translation adjustments for foreign operations, net of applicable deferred income taxes, as well as any gains or losses on intercompany balances for which settlement is not planned or anticipated in the foreseeable future, are included in “accumulated other comprehensive income (loss).”
	Monetary assets and liabilities denominated in currencies other than the functional currency of the applicable entity are revalued at the exchange rate in effect at the balance sheet date and revenues and expenses are translated at the exchange rate on the date the transaction occurs with the resulting foreign exchange gains and losses on settlement or revaluation recognized in income.
Goodwill and other intangible assets	The Company has recorded goodwill in connection with various acquisitions in prior years. Goodwill represents the excess of the purchase price over the fair value of net assets acquired. In accordance with GAAP authoritative guidance for goodwill and other intangible assets, the Company tests goodwill for potential impairment annually as of June 30, and between annual tests if an event occurs or circumstances change that may indicate that potential exists for the fair value of a reporting unit to be reduced to a level below its carrying amount. For further details on the factors considered in the goodwill impairment evaluation see Note 9, “Goodwill and Other Intangible Assets.”
	The Company’s indefinite lived intangible assets consist primarily of acquired insurance and reinsurance licenses. These assets are deemed to have indefinite useful lives and are therefore not subject to amortization. In accordance with GAAP authoritative guidance for goodwill and other intangible assets, the Company tests non-amortized intangible assets for potential impairment annually, or more frequently if events or changes in circumstances indicate that the asset might be impaired. Pursuant to the authoritative guidance, if the carrying value of a non-amortized intangible asset is in excess of its fair value, the asset must be written down to its fair value through the recognition of an impairment charge to earnings.
	All of the Company’s depreciable or amortizable long-lived assets such as premises, equipment, agency relationships, and acquired or internally-developed software, are carried at net book value, and are depreciated or amortized on a straight-line basis over their estimated useful lives. The amortization periods approximate the period over which the Company expects to generate future net cash inflows from the use of these assets. All of these assets are subject to impairment testing in accordance with authoritative guidance for the impairment or disposal of long-lived assets when events or conditions indicate that the carrying value of an asset may not be fully recoverable from future cash flows.
Variable interest entities ('VIEs')	Investments or other interests that absorb portions of an entity’s expected losses or receive portions of the entity’s expected residual returns are called variable interests. Entities in which the equity investors, as a group, do not have the characteristic of a controlling financial interest, or that do not have sufficient equity at risk to allow them to finance their own activities without additional financial support are referred to as VIEs.
	A VIE must be consolidated by its primary beneficiary, which is the variable interest holder that is determined to have the controlling financial interest in the entity. Based upon the nature of the VIE, this is either the entity that has both: a) the power to direct the VIE’s activities that most significantly impact its economic performance, and b) the obligation to absorb losses or receive benefits of the VIE that could potentially be significant to it; or it is the reporting entity that will absorb a majority of the VIE's expected losses, receive a majority of the VIE's expected residual returns, or both.
Non-controlling interests	Non-controlling shareholders' interests are presented separately in the Company's Consolidated Balance Sheets and Consolidated Statements of Shareholders' Equity as required under GAAP. The net loss (income) attributable to non-controlling interests is presented separately in the Company's Consolidated Statements of Comprehensive Income.
Losses and loss expenses	Unpaid losses and loss expenses include reserves for reported unpaid losses and loss expenses and for losses incurred but not reported. The reserve for reported unpaid losses and loss expenses for the Company’s property and casualty operations is established by management based on claims reported from insureds or amounts reported from ceding companies, and represent the estimated ultimate cost of events or conditions that have been reported to or specifically identified by the Company.
	The reserve for losses incurred but not reported is estimated by management based on loss development patterns determined by reference to the Company’s underwriting practices, the policy form, type of program and historical experience. The Company’s actuaries employ a variety of generally accepted methodologies to determine estimated ultimate loss reserves, including the “Bornhuetter-Ferguson incurred loss method” and frequency and severity approaches.
	Certain workers’ compensation and certain U.K. bodily injury liabilities are considered fixed and determinable and are discounted.
	Management believes that the reserves for unpaid losses and loss expenses are sufficient to cover losses that fall within coverages assumed by the Company. However, there can be no assurance that losses will not exceed the Company’s total reserves. The methodology of estimating loss reserves is periodically reviewed to ensure that the assumptions made continue to be appropriate and any adjustments resulting from such reviews are reflected in income in the year in which the adjustments are made.
Deposit liabilities	Contracts entered into by the Company that are not deemed to transfer significant underwriting and/or timing risk are accounted for as deposits, whereby liabilities are initially recorded at an amount equal to the assets received. The Company uses a portfolio rate of return of equivalent duration to the liabilities in determining risk transfer. An initial accretion rate is established based on actuarial estimates whereby the deposit liability is increased to the estimated amount payable over the term of the contract.
	The deposit accretion rate is the rate of return required to fund expected future payment obligations (this is equivalent to the “best estimate” of future cash flows), which are determined actuarially based upon the nature of the underlying indemnifiable losses. Accretion of the liability is recorded as interest expense.
	The Company periodically reassesses the estimated ultimate liability. Any changes to this liability are reflected as adjustments to interest expense to reflect the cumulative effect of the period the contract has been in force, and by an adjustment to the future accretion rate of the liability over the remaining estimated contract term.
Future policy benefit reserves	The Company estimates the present value of future policy benefits related to long duration contracts using assumptions for investment yields, mortality, and expenses, including a provision for adverse deviation.
	The assumptions used to determine future policy benefit reserves are best estimate assumptions that are determined at the inception of the contracts and are locked-in throughout the life of the contract unless a premium deficiency develops. As the experience on the contracts emerges, the assumptions are reviewed. If such review would produce reserves in excess of those currently held, then the locked-in assumptions will be revised and a claim and policy benefit is recognized at that time. The Company includes the cost of reinsurance in its premium deficiency considerations.
	Certain life insurance and annuity contracts provide the holder with a guarantee that the benefit received upon death will be no less than a minimum prescribed amount. The contracts are accounted for in accordance with the authoritative guidance on Accounting and Reporting by Insurance Enterprises for Certain Long- Duration Contracts and for Separate Accounts, which requires that the best estimate of future experience be combined with actual experience to determine the benefit ratio used to calculate the policy benefit reserve.
Income taxes	The Company utilizes the asset and liability method of accounting for income taxes. Under this method, deferred income taxes reflect the net tax effect of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The realizability of deferred tax assets is evaluated based upon management's assessment of taxable income in prior eligible carryback years, future reversals of existing taxable temporary differences, future taxable income exclusive of reversing temporary differences and carryforwards, and tax planning strategies that would, if necessary, be implemented. A valuation allowance may have to be established for any portion of a deferred tax asset that management believes will not be realized.
	The Company recognizes the tax benefit from an uncertain tax position taken only if it is more likely than not that the tax position will be sustained upon examination by the relevant tax authority, based on our interpretation of and judgment of the relevant tax law. The Company reviews its uncertain tax positions on a quarterly basis. Tax positions that meet the more likely than not threshold are measured using a probability weighted approach, whereby the largest amount of tax benefit that has a greater than 50% likelihood of being realized upon settlement is recognized. The Company recognizes interest and penalties on underpaid tax as a component of income tax expense.
	For the Company’s branch operations investment income is allocated and taxable in certain jurisdictions. The method of allocating this income may be different for tax reporting as compared to GAAP. The Company records the tax effects of this allocation entirely through operations.
Stock plans	At December 31, 2014, the Company had several stock-based performance incentive programs, which are described more fully in Note 20, “Share Capital.” Stock-based compensation issued under these plans generally has a life of not longer than ten years and vests as set forth at the time of grant. Awards currently vest annually over three or four years from the date of grant. The Company recognizes compensation costs for stock-based awards on a straight-line basis over the requisite service period (usually the vesting period) for each award.
	Share-based payments to employees, including grants of employee stock options, are recognized in the financial statements over the vesting period based on their grant date fair values.
	Authoritative guidance requires that compensation costs be recognized for unvested stock-based compensation awards over the period through the date that the employee is no longer required to provide future services to earn the award, rather than over the explicit service period. Accordingly, the Company follows a policy of recognizing compensation cost to coincide with the date that the employee is eligible to retire, rather than the actual retirement date, for all stock-based compensation granted.
Per share data	Basic earnings per ordinary share is based on weighted average ordinary shares outstanding and excludes any dilutive effects of options and convertible securities. Diluted earnings per ordinary share assumes the exercise of all dilutive stock options and conversion of convertible securities where the contingency for conversion has occurred or been satisfied.
Recent accounting pronouncements	In May 2011, the FASB issued an accounting standards update to amend existing requirements for fair value measurements and disclosures. The guidance expands the disclosure requirements around fair value measurements categorized in Level 3 of the fair value hierarchy, requiring quantitative and qualitative information to be disclosed related to: (1) the valuation processes used, (2) the sensitivity of the fair value measurement to changes in unobservable inputs and the interrelationships between those unobservable inputs, and (3) use of a nonfinancial asset in a way that differs from the asset’s highest and best use. The guidance requires disclosure of the level in the fair value hierarchy of items that are not measured at fair value, but whose fair value must be disclosed. It also clarifies and expands upon existing requirements for fair value measurements of financial assets and liabilities, as well as instruments classified in shareholders’ equity. The Company adopted this guidance from January 1, 2012; however, it impacted disclosure only and did not have an impact on the Company’s financial condition, results of operations or cash flows. See Note 4, “Fair Value Measurements,” for these updated disclosures.
	In June 2011, the FASB issued an accounting standards update concerning the presentation of comprehensive income in financial statements. This guidance allows an entity the option to present the total of comprehensive income, the components of net income, and the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements. Under both options, an entity is required to present each component of net income along with total net income, each component of other comprehensive income along with a total for other comprehensive income, and a total amount for comprehensive income. This guidance eliminates the option to present the components of other comprehensive income only as part of the statement of changes in shareholders' equity. The guidance does not change the items that must be reported in other comprehensive income or when an item of other comprehensive income must be reclassified to net income. The Company adopted this guidance from January 1, 2012; however, it did not have an impact on the Company's disclosure, financial condition, results of operations or cash flows. In February 2013, the FASB issued an additional accounting standards update related to this topic that requires an entity to provide information about the amounts reclassified out of accumulated other comprehensive income by component. The Company adopted this additional guidance prospectively from January 1, 2013. As this guidance is disclosure-related only and does not change the current requirements for reporting net income or other comprehensive income in financial statements, its adoption did not impact the Company's financial condition, results of operations or cash flows.
	In September 2011, the FASB issued an accounting standards update to simplify how entities test goodwill for impairment, by allowing an entity the option to first assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting entity is less than its carrying amount, as a basis for determining whether it is necessary to perform the two-step goodwill impairment test required under GAAP accounting rules. After assessing the circumstances that should be considered in making the qualitative assessment, if an entity determines that the fair value of a reporting unit as compared to its carrying value meets the threshold, then performing the two-step impairment step is unnecessary. In other circumstances, performance of the two-step test is required. The guidance also eliminates the option for an entity to carry forward its detailed calculation of a reporting unit’s fair value in certain situations. The Company adopted this guidance from January 1, 2012. It did not have an impact on the Company’s financial condition, results of operations, or cash flows.
	In December 2011, the FASB issued an accounting standards update requiring additional disclosures about financial instruments and derivatives that are either: (1) offset for balance sheet presentation purposes or (2) subject to an enforceable master netting arrangement or similar arrangement, regardless of whether they are offset for balance sheet presentation purposes. In January 2013, the FASB issued an additional accounting standards update related to this topic clarifying that the disclosures would apply only to derivatives, repurchase and reverse repurchase agreements, and securities borrowing and securities lending transactions, each to the extent that they met one of the two conditions provided in the initial accounting standards update. This guidance was adopted from January 1, 2013, on a retrospective basis for all fiscal periods presented. As this guidance is disclosure-related only and does not amend existing balance sheet offsetting guidance, its adoption did not impact the Company's financial condition, results of operations or cash flows.
	In July 2012, the FASB issued an accounting standards update to simplify how entities test indefinite-lived intangible assets for impairment. Under this new guidance, an entity is allowed the option to first assess qualitative factors to determine whether it is more likely than not that the fair value of an indefinite-lived intangible asset is less than its carrying value. After assessing the circumstances that should be considered in making the qualitative assessment, if an entity determines that the fair value of the intangible asset as compared to its carrying value meets the threshold, it may bypass the existing requirements to perform a full quantitative impairment test on the intangible asset, a test which otherwise would have to be performed annually, at a minimum. The guidance was effective during the fourth quarter of 2012. The Company adopted this guidance from January 1, 2013. It did not have an impact on the Company’s financial condition, results of operations or cash flows.
	In July 2013, the FASB issued an accounting standards update concerning the presentation of unrecognized tax benefits. The objective of the guidance is to improve the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The guidance seeks to reduce the diversity in practice by providing guidance on the presentation of unrecognized tax benefits to better reflect the manner in which an entity would settle, at the reporting date, any additional income taxes that would result from the disallowance of a tax position when net operating loss carryforwards, similar tax losses, or tax credit carryforwards exist. The guidance is effective for annual and interim reporting periods beginning after December 15, 2013, with both early adoption and retrospective application permitted. The Company adopted this guidance from January 1, 2014. It did not have an impact on the Company’s financial condition, results of operations or cash flows.
	In April 2014, the FASB issued an accounting standards update intended to improve financial reporting by changing key criteria used to evaluate whether disposal transactions meet the definition of discontinued operations. Under the guidance only those disposals of components of an entity - either by sale or otherwise - which represent strategic shifts that have, or will have, a major effect on an entity’s operations and financial results would qualify for reporting as discontinued operations. Disposals that are considered to be routine in nature can no longer be reported as discontinued operations. However, a disposal may now qualify for discontinued operations reporting even if the disposed component's operations and cash flows are not eliminated from on-going operations of the disposing entity, or if post-disposal, the disposing entity still has significant continuing involvement in the component’s operations. The standard also establishes both additional disclosure requirements and expanded disclosures regarding on-going involvement an entity may have with a discontinued operation after its disposal. The guidance is effective prospectively for all public company disposals (or component reclassifications to held-for-sale) that occur within annual periods beginning on or after December 15, 2014. Early adoption is permitted, but only for disposals (or component reclassifications to held-for-sale) that have not been reported in financial statements issued or available for issuance prior to the effective date. This guidance is not expected to have a significant impact on the Company's financial condition, results of operations or cash flows.
	In August 2014, the FASB issued an accounting standards update concerning the evaluation of an entity's ability to continue as a going concern. Under this new guidance, in connection with preparing financial statements for each annual and interim reporting period, an entity's management should evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity's ability to continue as a going concern within one year after the date that the financial statements are issued. Management's evaluation should be based on relevant conditions and events that are known and reasonably knowable at the date that the financial statements are issued. Substantial doubt exists when it is probable that the entity will be unable to meet its obligations as they become due. When management identifies conditions or events that raise substantial doubt about an entity's ability to continue as a going concern, management should consider whether its plans that are intended to mitigate those conditions or events will alleviate the substantial doubt. The mitigating effect of management's plans should be considered only to the extent that it is probable that the plans will be implemented, and if implemented, it is probable that the plans will be effective. If conditions or events raise substantial doubt, the entity should disclose the conditions or events, management's evaluation of their significance in relation to the ability to meet its obligations, and management's plans to mitigate the conditions or events along with whether substantial doubt has been alleviated. The guidance is effective for annual periods ending after December 15, 2016, and interim and annual periods thereafter. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on its financial condition, results of operations or cash flows.
	In November 2014, the FASB issued an accounting standards update which provides an acquired entity with the option to reflect assets and liabilities using its acquirer's accounting and reporting basis ("pushdown accounting") within its own separate financial statements. Under this new guidance, an acquired entity may elect the option to apply pushdown accounting in the reporting period in which the change-in control event occurs (on a case by case basis if multiple). If the entity elects to apply pushdown accounting, it should disclose information that enables users of the financial statements to evaluate the effect of pushdown accounting. If pushdown accounting is not applied in the initial reporting period, an acquired entity will have the option to elect to apply it in a subsequent reporting period, however, such an election should be considered a change in accounting principle. Once pushdown accounting is elected, that election is irrevocable. The guidance was effective upon issuance. Its adoption did not have an impact on the financial condition, results of operations or cash flows of the Company or its subsidiaries for the year ended December 31, 2014.

Sale_of_Life_Reinsurance_Subsi1

Sale of Life Reinsurance Subsidiary (Tables)	12 Months Ended
	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Impact of Life Retro Arrangements	The impact of the Life Retro Arrangements on the Company's results from the completion of the transaction on May 30, 2014 through December 31, 2014 was as follows:


	Impact of Life Retro Arrangements	May 30 to December 31,
	(U.S. dollars in thousands)	2014
	Underwriting profit (loss) (1)	$	11,649

	Net investment income - Life Funds Withheld Assets	129,575

	Net realized gains (losses) on investments sold - Life Funds Withheld Assets	5,067

	Net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets	(9		)
	OTTI on investments - Life Funds Withheld Assets	(20,587		)
	Exchange (gains) losses	10,099

	Other income and expenses	(1,610		)
	Net realized and unrealized gains (losses) on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets	(488,222		)
	Net income (loss)	$	(354,038	)
	Change in net unrealized gains (losses) on investments - Life Funds Withheld Assets, net of tax	274,083

	Change in adjustments related to future policy benefit reserves, net of tax	74,009

	Change in cumulative translation adjustment - Life Funds Withheld Assets, net of tax	17,595

	Total changes to other comprehensive income as a result of Life Retro Arrangements	$	365,687

	Comprehensive income (loss) (1)	$	11,649

	____________

	-1	The underwriting profit of $11.6 million relates to a premium adjustment relating to the Life Retro Arrangements transaction which was completed on May 30, 2014. Excluding this transaction, the impact to comprehensive income relating to the Life Retro Arrangements was nil for the year ended December 31, 2014.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Summary of assets and liabilities that were accounted for at fair value	The following tables set forth the Company’s assets and liabilities that were accounted for at fair value at December 31, 2014 and 2013 by level within the fair value hierarchy. For further information, see Note 2 (b), “Significant Accounting Policies – Fair Value Measurements”:


	31-Dec-14	Quoted Prices				Significant Other				Significant Other				Collateral and				Balance at
	(U.S. dollars in thousands)	in Active Markets for				Observable				Unobservable				Counterparty				December 31,
		Identical Assets				Inputs				Inputs				Netting				2014
		(Level 1)				(Level 2)				(Level 3)
	Assets
	Fixed maturities - Available for Sale ("AFS") - Excluding Life Funds Withheld Assets
	U.S. Government and Government - Related/Supported	$	—			$	2,171,953			$	—			$	—			$	2,171,953

	Corporate (1)	—				8,772,479				5,894				—				8,778,373

	Residential mortgage-backed securities – Agency (“RMBS - Agency”)	—				3,726,666				1,910				—				3,728,576

	Residential mortgage-backed securities – Non-Agency (“RMBS - Non-Agency”)	—				427,351				—				—				427,351

	Commercial mortgage-backed securities (“CMBS”)	—				1,052,544				—				—				1,052,544

	Collateralized debt obligations (“CDO”)	—				4,076				687,958				—				692,034

	Other asset-backed securities (1)	—				1,060,005				5,288				—				1,065,293

	U.S. States and political subdivisions of the States	—				2,021,272				—				—				2,021,272

	Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	—				4,240,073				—				—				4,240,073

	Total fixed maturities - AFS - Excluding Life Funds Withheld Assets, at fair value	$	—			$	23,476,419			$	701,050			$	—			$	24,177,469

	Equity securities, at fair value	502,284				366,008				—				—				868,292

	Short-term investments, at fair value (1)(2)	—				256,727				—				—				256,727

	Total investments AFS - Excluding Life Funds Withheld Assets	$	502,284			$	24,099,154			$	701,050			$	—			$	25,302,488

	Fixed maturities - AFS - Life Funds Withheld Assets
	U.S. Government and Government - Related/Supported	—				18,724				—				—				18,724

	Corporate (1)	—				2,817,980				—				—				2,817,980

	RMBS - Agency	—				3,782				—				—				3,782

	RMBS - Non-Agency	—				85,335				—				—				85,335

	CMBS	—				193,167				—				—				193,167

	Other asset-backed securities	—				273,541				—				—				273,541

	Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	—				1,789,036				—				—				1,789,036

	Total fixed maturities - AFS - Life Funds Withheld Assets, at fair value	—				5,181,565				—				—				5,181,565

	Total investments - AFS, at fair value	502,284				29,280,719				701,050				—				30,484,053

	Fixed maturities - Trading
	Corporate (1)	—				1,171				—				—				1,171

	Total fixed maturities - Trading, at fair value	—				1,171				—				—				1,171

	Cash equivalents (3)	1,103,877				397,955				—				—				1,501,832

	Cash equivalents - Life Funds Withheld Assets	460				132,738				—				—				133,198

	Other investments (4)	—				708,974				185,083				—				894,057

Other assets (5)	—				122,996				13,663				(696		)		135,963

Total assets accounted for at fair value	$	1,606,621			$	30,644,553			$	899,796			$	(696	)		$	33,150,274

Liabilities
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable) (6)	$	—			$	450,831			$	—			$	—			$	450,831

Financial instruments sold, but not yet purchased (7)	4,737				25,669				—				—				30,406

Other liabilities (5)	—				7,757				23,427				(696		)		30,488

Total liabilities accounted for at fair value	$	4,737			$	484,257			$	23,427			$	(696	)		$	511,725



31-Dec-13	Quoted Prices				Significant Other				Significant Other				Collateral and				Balance at
(U.S. dollars in thousands)	in Active Markets for				Observable				Unobservable				Counterparty				December 31,
	Identical Assets				Inputs				Inputs				Netting				2013
	(Level 1)				(Level 2)				(Level 3)
Assets
U.S. Government and Government - Related/Supported	$	—			$	2,501,851			$	—			$	—			$	2,501,851

Corporate (1)	—				11,094,257				31,573				—				11,125,830

RMBS – Agency	—				3,535,649				10,473				—				3,546,122

RMBS – Non-Agency	—				398,759				9				—				398,768

CMBS	—				1,234,262				12,533				—				1,246,795

CDO	—				7,060				710,253				—				717,313

Other asset-backed securities (1)	—				1,230,227				11,877				—				1,242,104

U.S. States and political subdivisions of the States	—				1,845,812				—				—				1,845,812

Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	—				4,875,541				—				—				4,875,541

Total fixed maturities, at fair value	$	—			$	26,723,418			$	776,718			$	—			$	27,500,136

Equity securities, at fair value	540,331				499,906				—				—				1,040,237

Short-term investments, at fair value (1)(2)	—				454,273				2,015				—				456,288

Total investments available for sale	$	540,331			$	27,677,597			$	778,733			$	—			$	28,996,661

Cash equivalents (3)	834,514				226,636				—				—				1,061,150

Other investments (4)	—				757,110				113,472				—				870,582

Other assets (5)	—				27,487				—				(1,342		)		26,145

Total assets accounted for at fair value	$	1,374,845			$	28,688,830			$	892,205			$	(1,342	)		$	30,954,538

Liabilities
Financial instruments sold, but not yet purchased (7)	$	—			$	28,861			$	—			$	—			$	28,861

Other liabilities (5)	—				76,375				29,110				(1,342		)		104,143

Total liabilities accounted for at fair value	$	—			$	105,236			$	29,110			$	(1,342	)		$	133,004


____________

-1	Included are certain medium term notes supported primarily by pools of European investment grade credit with varying degrees of leverage. The notes had a fair value of $79.9 million and $154.6 million and an amortized cost of $68.4 million and $147.7 million at December 31, 2014 and December 31, 2013, respectively. These notes allow the investor to participate in cash flows of the underlying bonds including certain residual values, which could serve to either decrease or increase the ultimate values of these notes.

-2	Short-term investments consist primarily of Corporate securities and U.S. and Non-U.S. Government and Government-Related/ Supported securities.

-3	Cash equivalents balances subject to fair value measurement include certificates of deposit and money market funds. Operating cash balances are not subject to recurring fair value measurement guidance.

-4	The Other investments balance excludes certain structured transactions including certain investments in project finance transactions, a payment obligation and liquidity financing provided to a structured credit vehicle as a part of a third party medium term note facility. These investments, which totaled $354.4 million at December 31, 2014 and $294.0 million at December 31, 2013, are carried at amortized cost. For further information, see Note 8, “Other Investments.”

-5	Other assets and other liabilities include derivative instruments. The derivative balances included in each category are reported on a gross basis by level with a netting adjustment presented separately in the Collateral and Counterparty Netting column. The fair values of the individual derivative contracts are reported gross in their respective levels based on the fair value hierarchy. For further details regarding derivative fair values and associated collateral received or paid see Note 16, “Derivative Instruments."

-6	Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable) include balances related to the life retrocession embedded derivative, under which all investment results associated with the Life Funds Withheld Assets related the Life Retro Arrangements described in Note 3, "Sale of Life Reinsurance Subsidiary", accrue to the benefit of GCLR.

-7	Financial instruments sold, but not yet purchased, represent “short sales” and are included within “Payable for investments purchased” on the balance sheets.
Additional information about assets and liabilities measured at fair value on a recurring basis - Level 3

	(U.S. dollars in thousands)	Level 3 Assets and Liabilities – Year Ended December 31, 2014
		Corporate				RMBS – Agency				RMBS –				CMBS				CDO
										Non Agency
	Balance, beginning of period	$	31,573			$	10,473			$	9			$	12,533			$	710,253

	Realized gains (losses)	199				5				1				3				3,781

	Movement in unrealized gains (losses)	(128		)		(18		)		1				(3		)		11,604

	Purchases and issuances	3,759				120				—				1,376				185,710

	Sales	—				—				—				—				(48,313		)

	Settlements	(6,543		)		(3,205		)		(11		)		(12,533		)		(175,077		)
	Transfers into Level 3	766				—				—				—				—

	Transfers out of Level 3	(23,732		)		(5,465		)		—				(1,376		)		—

	Fixed maturities to short-term investments classification change	—				—				—				—				—

	Balance, end of period	$	5,894			$	1,910			$	—			$	—			$	687,958

	Movement in total gains (losses) above relating to instruments still held at the reporting date	$	60			$	(12	)		$	—			$	—			$	14,432




	(U.S. dollars in thousands)	Level 3 Assets and Liabilities – Year Ended December 31, 2014
		Other asset-				Non-US Sovereign				Short-term				Other				Derivative
		backed				Government,				investments				investments				Contracts – Net
		securities				Provincial,
						Supranational and
						Government
						Related/Supported
	Balance, beginning of period	$	11,877			$	—			$	2,015			$	113,472			$	(29,110	)

	Realized gains (losses)	(7		)		—				—				12,676				—

	Movement in unrealized gains (losses)	65				—				(15		)		538				19,346

	Purchases and issuances	5,182				—				—				59,401				—

	Sales	—				—				—				—				—

	Settlements	(5,705		)		—				(2,000		)		(25,498		)		—

	Transfers into Level 3	—				—				—				24,494				—

	Transfers out of Level 3	(6,124		)		—				—								—

	Fixed maturities to short-term investments classification change	—				—				—				—				—

	Balance, end of period	$	5,288			$	—			$	—			$	185,083			$	(9,764	)

	Movement in total gains (losses) above relating to instruments still held at the reporting date	$	57			$	—			$	—			$	13,212			$	19,346





	(U.S. dollars in thousands)	Level 3 Assets and Liabilities – Year Ended December 31, 2013
		Corporate				RMBS – Agency				RMBS –				CMBS				CDO
Non Agency
Balance, beginning of period			$	30,098			$	32,005			$	116			$	25,347			$	701,736

Realized gains (losses)	4				10				(1		)		3				4,364

Movement in unrealized gains (losses)	766				(23		)		(1		)		(68		)		37,916

Purchases and issuances	10,691				—				3,326				—				136,035

Sales	(71		)		(535		)		—				—				(48,226		)

Settlements	(7,274		)		(3,349		)		(105		)		(12,749		)		(121,572		)
Transfers into Level 3	—				—				—				—				—

Transfers out of Level 3	(2,641		)		(17,635		)		(3,326		)		—				—

Fixed maturities to short-term investments classification change	—				—				—				—				—

Balance, end of period	$	31,573			$	10,473			$	9			$	12,533			$	710,253

Movement in total gains (losses) above relating to instruments still held at the reporting date	$	845			$	(27	)		$	(1	)		$	(65	)		$	39,259




(U.S. dollars in thousands)	Level 3 Assets and Liabilities – Year Ended December 31, 2013
	Other asset-				Non-US Sovereign				Short-term				Other				Derivative
	backed				Government,				investments				investments				Contracts – Net
	securities				Provincial,
					Supranational and
					Government
					Related/Supported
Balance, beginning of period	$	18,128			$	—			$	—			$	115,272			$	(36,247	)

Realized gains (losses)	848				—				(17		)		7,545				—

Movement in unrealized gains (losses)	1,691				—				15				4,095				7,137

Purchases and issuances	21,686				—				2,017				18,340				—

Sales	(15,711		)		—				—				(1,237		)		—

Settlements	(8,259		)		—				—				(30,543		)		—

Transfers into Level 3	—				—				—				—				—

Transfers out of Level 3	(6,506		)		—				—				—				—

Fixed maturities to short-term investments classification change	—				—				—				—				—

Balance, end of period	$	11,877			$	—			$	2,015			$	113,472			$	(29,110	)

Movement in total gains (losses) above relating to instruments still held at the reporting date	$	(515	)		$	—			$	(2	)		$	10,750			$	7,137

Financial instruments for which the carrying values differs from the estimated fair value

	(U.S. dollars in thousands)	2014								2013
		Carrying Value				Fair Value				Carrying Value				Fair Value
	Fixed maturities, held to maturity	$	—			$	—			$	2,858,695			$	3,131,235

	Other investments – structured transactions and other	354,382				371,625				294,048				296,799

	Financial Assets	$	354,382			$	371,625			$	3,152,743			$	3,428,034

	Deposit liabilities	$	1,245,367			$	1,543,761			$	1,509,243			$	1,718,394

	Notes payable and debt	1,662,580				1,897,854				2,263,203				2,429,412

	Financial Liabilities	$	2,907,947			$	3,441,615			$	3,772,446			$	4,147,806

Segment_Information_Tables

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Schedule of segment reporting, by segment	The following tables summarize the segment results for the indicated years ended:


	Year Ended December 31, 2014	Insurance				Reinsurance				Total P&C				Corporate and Other (1)				Total
	(U.S. dollars in thousands, except ratios)
	Gross premiums written	$	5,976,011			$	1,785,479			$	7,761,490			$	333,436			$	8,094,926

	Net premiums written	4,134,151				1,633,058				5,767,209				177,632				5,944,841

	Net premiums earned	4,026,713				1,690,725				5,717,438				177,632				5,895,070

	Net losses and loss expenses	2,543,108				715,285				3,258,393				242,963				3,501,356

	Acquisition costs	393,319				330,684				724,003				14,115				738,118

	Operating expenses (2)	865,592				193,404				1,058,996				10,693				1,069,689

	Underwriting profit (loss)	$	224,694			$	451,352			$	676,046			$	(90,139	)		$	585,907

	Net investment income - excluding Life Funds Withheld Assets (3)									574,458				146,558				721,016

	Net investment income - Life Funds Withheld Assets													129,575				129,575

	Net results from structured products (4)	43,710				10,499				54,209				—				54,209

	Net fee income and other (5)	(10,051		)		2,800				(7,251		)		360				(6,891		)

	Loss on sale of life reinsurance subsidiary									—				666,423				666,423

	Net realized gains (losses) on investments - excluding Life Funds Withheld Assets									119,366				3,625				122,991

	Net realized gains (losses) on investments and net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets									—				(15,529		)		(15,529		)

	Net realized and unrealized gains (losses) on derivative instruments									—				29,886				29,886

	Net realized and unrealized gains (losses) on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets									—				(488,222		)		(488,222		)

	Net income (loss) from investment fund affiliates and operating affiliates (6)									—				203,034				203,034

	Exchange (gains) losses									—				(37,568		)		(37,568		)

	Corporate operating expenses									—				220,165				220,165

	Contribution from P&C and Corporate and Other									1,416,828				(929,872		)		486,956

	Interest expense (7)													121,221				121,221

	Non-controlling interests													80,498				80,498

	Income tax expense													96,897				96,897

	Net income (loss) attributable to ordinary shareholders																	$	188,340

	Ratios – P&C operations: (8)
	Loss and loss expense ratio	63.2		%		42.3		%		57		%
	Underwriting expense ratio	31.2		%		31		%		31.2		%
	Combined ratio	94.4		%		73.3		%		88.2		%
	____________

	-1	Corporate and Other includes other items of our revenue and expenditures that are not evaluated at the segment level for reporting purposes, as well as the Company's Run-Off Life Operations.

	-2	Operating expenses of the segments exclude Corporate operating expenses, shown separately.

	-3	Net investment income - excluding Life Funds Withheld Assets does not include net investment income related to the net results from structured products.

-4	The net results from P&C structured products include net investment income and interest expense of $68.0 million and $12.9 million, respectively.

-5	Net fee income and other includes operating expenses from the Company's loss prevention consulting services business.

-6	The Company generally records the income related to the alternative funds and to the private investment and operating fund affiliates on a one-month and three-month lag, respectively.

-7	Interest expense excludes interest expense related to deposit liabilities recorded in the Insurance and Reinsurance segments.

-8	Ratios are based on net premiums earned from P&C operations.



Year Ended December 31, 2013	Insurance				Reinsurance				Total P&C				Corporate & Other (1)				Total
(U.S. dollars in thousands, except ratios)
Gross premiums written	$	5,523,181			$	1,893,611			$	7,416,792			$	324,343			$	7,741,135

Net premiums written	4,154,093				1,749,889				5,903,982				295,422				6,199,404

Net premiums earned	4,267,677				1,746,422				6,014,099				295,422				6,309,521

Net losses and loss expenses	2,829,999				901,465				3,731,464				465,702				4,197,166

Acquisition costs	529,270				353,388				882,658				26,665				909,323

Operating expenses (2)	782,677				166,238				948,915				8,926				957,841

Underwriting profit (loss)	$	125,731			$	325,331			$	451,062			$	(205,871	)		$	245,191

Net investment income (3)									599,144				286,645				885,789

Net results from structured products (4)	15,562				8,229				23,791				—				23,791

Net fee income and other (5)	(9,317		)		2,320				(6,997		)		1,305				(5,692		)

Net realized gains (losses) on investments									85,792				1,985				87,777

Net realized and unrealized gains (losses) on derivative instruments									—				7,798				7,798

Net income (loss) from investment fund affiliates and operating affiliates (6)									—				258,195				258,195

Exchange (gains) losses									—				(28,243		)		(28,243		)

Corporate operating expenses									—				209,454				209,454

Contribution from P&C and Corporate and Other									1,152,792				168,846				1,321,638

Interest expense (7)													107,486				107,486

Non-controlling interests													76,731				76,731

Income tax expense													77,505				77,505

Net income (loss) attributable to ordinary shareholders																	$	1,059,916

Ratios – P&C operations: (8)
Loss and loss expense ratio	66.3		%		51.6		%		62		%
Underwriting expense ratio	30.8		%		29.8		%		30.5		%
Combined ratio	97.1		%		81.4		%		92.5		%
____________

-1	Corporate and Other includes other items of our revenue and expenditures that are not evaluated at the segment level for reporting purposes, as well as the Company's Run-Off Life Operations.

-2	Operating expenses of the segments exclude Corporate operating expenses, shown separately.

-3	Net investment income does not include net investment income related to the net results from structured products.

-4	The net results from P&C structured products include net investment income and interest expense of $71.9 million and $48.0 million, respectively.

-5	Net fee income and other includes operating expenses from the Company's loss prevention consulting services business.

-6	The Company generally records the income related to the alternative funds and to the private investment and operating fund affiliates on a one-month and three-month lag, respectively.

-7	Interest expense excludes interest expense related to deposit liabilities recorded in the Insurance and Reinsurance segments.

-8	Ratios are based on net premiums earned from P&C operations.




Year Ended December 31, 2012	Insurance				Reinsurance				Total P&C				Corporate and Other (1)				Total
(U.S. dollars in thousands, except ratios)
Gross premiums written	$	5,166,973			$	2,008,157			$	7,175,130			$	355,753			$	7,530,883

Net premiums written	4,072,511				1,884,508				5,957,019				324,432				6,281,451

Net premiums earned	3,924,636				1,841,342				5,765,978				324,459				6,090,437

Net losses and loss expenses	2,691,056				1,074,426				3,765,482				486,195				4,251,677

Acquisition costs	504,227				368,172				872,399				41,093				913,492

Operating expenses (2)	754,308				157,657				911,965				9,335				921,300

Underwriting profit (loss)	$	(24,955	)		$	241,087			$	216,132			$	(212,164	)		$	3,968

Net investment income (3)									641,237				299,443				940,680

Net results from structured products (4)	20,978				(15,721		)		5,257				—				5,257

Net fee income and other (5)	850				2,492				3,342				426				3,768

Net realized gains (losses) on investments									35,101				(21,003		)		14,098

Net realized and unrealized gains (losses) on derivative instruments									—				5,221				5,221

Net income (loss) from investment fund affiliates and operating affiliates (6)									—				112,391				112,391

Exchange (gains) losses									—				10,545				10,545

Corporate operating expenses									—				204,502				204,502

Contribution from P&C and Corporate and Other									901,069				(30,733		)		870,336

Interest expense (7)													105,925				105,925

Non-controlling interests													79,255				79,255

Income tax expense													34,028				34,028

Net income (loss) attributable to ordinary shareholders																	$	651,128

Ratios – P&C operations: (8)
Loss and loss expense ratio	68.6		%		58.4		%		65.3		%
Underwriting expense ratio	32		%		28.5		%		31		%
Combined ratio	100.6		%		86.9		%		96.3		%

____________

-1	Corporate and Other includes other items of our revenue and expenditures that are not evaluated at the segment level for reporting purposes, as well as the Company's Run-Off Life Operations.

-2	Operating expenses exclude Corporate operating expenses, shown separately.

-3	Net investment income does not include net investment income related to the net results from structured products.

-4	The net results from P&C structured products include net investment income and interest expense of $71.7 million and $66.3 million, respectively.

-5	Net fee income and other includes operating expenses from the Company's loss prevention consulting services business.

-6	The Company generally records the income related to the alternative funds and to the private investment and operating fund affiliates on a one-month and three-month lag, respectively.

-7	Interest expense excludes interest expense related to deposit liabilities recorded in the Insurance and Reinsurance segments.

-8	Ratios are based on net premiums earned from P&C operations.
Schedule of net premiums earned by line of business	The following tables summarize the Company’s net premiums earned by line of business:


	Year Ended December 31, 2014	Insurance				Reinsurance				Corporate and Other				Total
	(U.S. dollars in thousands)
	P&C Operations:
	Professional	$	1,075,420			$	181,223			$	—			$	1,256,643

	Casualty	1,422,684				300,223				—				1,722,907

	Property catastrophe	—				433,602				—				433,602

	Property	544,856				555,583				—				1,100,439

	Marine, energy, aviation and satellite	—				95,745				—				95,745

	Specialty	737,281				—				—				737,281

	Other (1)	246,472				124,349				—				370,821

	Total P&C Operations	$	4,026,713			$	1,690,725			$	—			$	5,717,438

	Corporate and Other:
	Run-Off Life Operations - Annuity	—				—				53,363				53,363

	Run-Off Life Operations - Other Life	—				—				124,269				124,269

	Total Corporate and Other	$	—			$	—			$	177,632			$	177,632

	Total	$	4,026,713			$	1,690,725			$	177,632			$	5,895,070

	Year Ended December 31, 2013
	P&C Operations:
	Professional	$	1,370,196			$	206,169			$	—			$	1,576,365

	Casualty	1,389,851				312,156				—				1,702,007

	Property catastrophe	—				492,568				—				492,568

	Property	544,278				561,105				—				1,105,383

	Marine, energy, aviation and satellite	—				94,797				—				94,797

	Specialty	732,042				—				—				732,042

	Other (1)	231,310				79,627				—				310,937

	Total P&C Operations	$	4,267,677			$	1,746,422			$	—			$	6,014,099

	Corporate and Other:
	Run-Off Life Operations - Annuity	$	—			$	—			$	122,715			$	122,715

	Run-Off Life Operations - Other Life	—				—				172,707				172,707

	Total Corporate and Other	$	—			$	—			$	295,422			$	295,422

	Total	$	4,267,677			$	1,746,422			$	295,422			$	6,309,521

	Year Ended December 31, 2012
	P&C Operations:
	Professional	$	1,350,319			$	213,324			$	—			$	1,563,643

	Casualty	1,165,753				311,166				—				1,476,919

Property catastrophe	—				463,975				—				463,975

Property	489,739				613,291				—				1,103,030

Marine, energy, aviation and satellite	—				147,362				—				147,362

Specialty	708,568				—				—				708,568

Other (1)	210,257				92,224				—				302,481

Total P&C Operations	$	3,924,636			$	1,841,342			$	—			$	5,765,978

Corporate and Other:
Run-Off Life Operations - Annuity	$	—			$	—			$	126,912			$	126,912

Run-Off Life Operations - Other Life	—				—				197,547				197,547

Total Corporate and Other	$	—			$	—			$	324,459			$	324,459

Total	$	3,924,636			$	1,841,342			$	324,459			$	6,090,437

____________

-1	Other within the Insurance segment includes: excess and surplus, programs, surety, structured indemnity and certain discontinued lines. Other within the Reinsurance segment includes: whole account contracts, accident and health and other lines.
Schedule of net premiums written by geographic location	The following table shows an analysis of the Company’s net premiums written by geographical location of subsidiary where the premium is written for the years ended December 31:


	(U.S. dollars in thousands)	2014				2013				2012
	P&C Operations:
	Bermuda	$	636,109			$	658,041			$	644,566

	United States	2,528,196				2,650,916				2,626,855

	Europe	2,124,117				2,111,065				2,202,209

	Other	478,787				483,960				483,389

	Total P&C Operations	$	5,767,209			$	5,903,982			$	5,957,019

	Corporate and Other:
	Bermuda	$	91,979			$	117,948			$	129,997

	Europe	85,653				177,474				194,435

	Total Corporate and Other	$	177,632			$	295,422			$	324,432

Investments_Tables

Investments (Tables)	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Amortized cost and fair value summary	The cost (amortized cost for fixed maturities and short-term investments), fair value, gross unrealized gains and gross unrealized (losses), including OTTI recorded in accumulated other comprehensive income (“AOCI”) of the Company’s AFS and HTM investments at December 31, 2014 and 2013, were as follows:


						Included in AOCI
	31-Dec-14	Cost or				Gross				Gross Unrealized Losses				Fair Value				Non-credit Related OTTI (1)
	(U.S. dollars in thousands)	Amortized				Unrealized
		Cost				Gains
	Fixed maturities - AFS
	U.S. Government and Government-Related/Supported	$	2,100,851			$	77,889			$	(6,787	)		$	2,171,953			$	—

	Corporate (2)	8,462,130				365,805				(49,562		)		8,778,373				(3,309		)

	RMBS – Agency	3,625,171				114,188				(10,783		)		3,728,576				—

	RMBS – Non-Agency	404,398				41,108				(18,155		)		427,351				(67,918		)

	CMBS	1,033,819				23,987				(5,262		)		1,052,544				(2,033		)

	CDO	717,544				1,659				(27,169		)		692,034				(1,663		)

	Other asset-backed securities (2)	1,028,528				42,810				(6,045		)		1,065,293				(1,797		)

	U.S. States and political subdivisions of the States	1,892,566				129,910				(1,204		)		2,021,272				—

	Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	4,162,425				139,484				(61,836		)		4,240,073				—

	Total fixed maturities - AFS - Excluding Life Funds Withheld Assets	$	23,427,432			$	936,840			$	(186,803	)		$	24,177,469			$	(76,720	)

	Total short-term investments	257,221				49				(543		)		256,727				—

	Total equity securities	763,833				130,689				(26,230		)		868,292				—

	Total investments - AFS - Excluding Life Funds Withheld Assets	$	24,448,486			$	1,067,578			$	(213,576	)		$	25,302,488			$	(76,720	)

	Fixed maturities - AFS - Life Funds Withheld Assets

	U.S. Government and Government-Related/Supported	$	14,866			$	3,858			$	—			$	18,724			$	—

	Corporate	2,407,849				410,131				—				2,817,980				—

	RMBS – Agency	3,301				481				—				3,782				—

	RMBS – Non-Agency	71,075				14,260				—				85,335				—

	CMBS	168,886				24,281				—				193,167				—

	CDO	—				—				—				—				—

	Other asset-backed securities	238,168				35,373				—				273,541				—

	U.S. States and political subdivisions of the States	—				—				—				—				—

	Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	1,397,194				391,842				—				1,789,036				—

	Total fixed maturities - AFS - Life Funds Withheld Assets	$	4,301,339			$	880,226			$	—			$	5,181,565			$	—

	Total investments - AFS	$	28,749,825			$	1,947,804			$	(213,576	)		$	30,484,053			$	(76,720	)

	Total fixed maturities - HTM	$	—			$	—			$	—			$	—			$	—


	31-Dec-14													Amortized				Fair Value
	(U.S. dollars in thousands)													Cost
	Fixed maturities - Trading - Life Funds Withheld Assets

Corporate													1,180				1,171

Total investments - Trading - Life Funds Withheld Assets													$	1,180			$	1,171


____________

-1	Represents the non-credit component of OTTI losses, adjusted for subsequent sales of securities. It does not include the change in fair value subsequent to the impairment measurement date.

-2	Included are certain medium term notes supported primarily by pools of European investment grade credit with varying degrees of leverage. The notes have a fair value of $79.9 million and an amortized cost of $68.4 million. These notes allow the investor to participate in cash flows of the underlying bonds including certain residual values, which could serve to either decrease or increase the ultimate values of these notes.




					Included in AOCI
31-Dec-13	Cost or				Gross				Gross Unrealized Losses				Fair Value				Non-credit Related OTTI (1)
(U.S. dollars in thousands)	Amortized				Unrealized
	Cost				Gains
Fixed maturities - AFS
U.S. Government and Government-Related/Supported	$	2,484,193			$	51,701			$	(34,043	)		$	2,501,851			$	—

Corporate (2)	10,802,332				433,097				(109,599		)		11,125,830				(4,758		)

RMBS – Agency	3,540,101				68,098				(62,077		)		3,546,122				—

RMBS – Non-Agency	396,798				33,096				(31,126		)		398,768				(74,528		)

CMBS	1,223,313				39,255				(15,773		)		1,246,795				(2,753		)

CDO	754,414				5,833				(42,934		)		717,313				(2,036		)

Other asset-backed securities (2)	1,210,384				40,560				(8,840		)		1,242,104				(2,807		)

U.S. States and political subdivisions of the States	1,821,499				55,083				(30,770		)		1,845,812				—

Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	4,878,840				80,961				(84,260		)		4,875,541				—

Total fixed maturities - AFS	$	27,111,874			$	807,684			$	(419,422	)		$	27,500,136			$	(86,882	)

Total short-term investments	455,470				962				(144		)		456,288				—

Total equity securities	903,201				154,506				(17,470		)		1,040,237				—

Total investments - AFS	$	28,470,545			$	963,152			$	(437,036	)		$	28,996,661			$	(86,882	)

Fixed maturities - HTM
U.S. Government and Government-Related/Supported	$	10,993			$	629			$	—			$	11,622			$	—

Corporate	1,386,863				113,179				(968		)		1,499,074				—

RMBS – Non-Agency	66,987				4,985				—				71,972				—

CMBS	144,924				11,864				—				156,788				—

Other asset-backed securities	106,540				6,908				—				113,448				—

Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	1,142,388				136,585				(642		)		1,278,331				—

Total investments - HTM	$	2,858,695			$	274,150			$	(1,610	)		$	3,131,235			$	—


____________

-1	Represents the non-credit component of OTTI losses, adjusted for subsequent sales of securities. It does not include the change in fair value subsequent to the impairment measurement date.

-2	Included are certain medium term notes supported primarily by pools of European investment grade credit with varying degrees of leverage. The notes have a fair value of $154.6 million and an amortized cost of $147.7 million. These notes allow the investor to participate in cash flows of the underlying bonds including certain residual values, which could serve to either decrease or increase the ultimate values of these notes.
Contractual maturities summary	The contractual maturities of AFS and HTM fixed income securities at December 31, 2014 and 2013 are shown below. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.


	(U.S. dollars in thousands)	31-Dec-14								31-Dec-13
		Amortized				Fair				Amortized				Fair
		Cost				Value				Cost				Value
	Fixed maturities - AFS
	Due less than one year	$	1,972,224			$	1,980,429			$	2,052,251			$	2,060,365

	Due after 1 through 5 years	8,919,037				9,113,651				10,075,087				10,305,986

	Due after 5 through 10 years	4,232,396				4,412,569				5,474,120				5,507,450

	Due after 10 years	1,494,315				1,705,022				2,385,406				2,475,233

		$	16,617,972			$	17,211,671			$	19,986,864			$	20,349,034

	RMBS – Agency	$	3,625,171			$	3,728,576			$	3,540,101			$	3,546,122

	RMBS – Non-Agency	404,398				427,351				396,798				398,768

	CMBS	1,033,819				1,052,544				1,223,313				1,246,795

	CDO	717,544				692,034				754,414				717,313

	Other asset-backed securities	1,028,528				1,065,293				1,210,384				1,242,104

	Total mortgage and asset-backed securities	$	6,809,460			$	6,965,798			$	7,125,010			$	7,151,102

	Total fixed maturities - AFS	$	23,427,432			$	24,177,469			$	27,111,874			$	27,500,136

	Fixed maturities - AFS - Life Funds Withheld Assets
	Due less than one year	$	117,048			$	125,326			$	—			$	—

	Due after 1 through 5 years	638,526				685,787				—				—

	Due after 5 through 10 years	1,004,698				1,165,348				—				—

	Due after 10 years	2,059,637				2,649,279				—				—

		$	3,819,909			$	4,625,740			$	—			$	—

	RMBS – Agency	$	3,301			$	3,782			$	—			$	—

	RMBS – Non-Agency	71,075				85,335				—				—

	CMBS	168,886				193,167				—				—

	CDO	—				—				—				—

	Other asset-backed securities	238,168				273,541				—				—

	Total mortgage and asset-backed securities	$	481,430			$	555,825			$	—			$	—

	Total fixed maturities - AFS - Life Funds Withheld Assets	$	4,301,339			$	5,181,565			$	—			$	—

	Total fixed maturities - AFS	$	27,728,771			$	29,359,034			$	27,111,874			$	27,500,136

	Fixed maturities - Trading - Life Funds Withheld Assets
	Due less than one year	$	—			$	—			$	—			$	—

	Due after 1 through 5 years	—				—				—				—

	Due after 5 through 10 years	1,180				1,171				—				—

Due after 10 years	—				—				—				—

Total fixed maturities - Trading - Life Funds Withheld Assets	$	1,180			$	1,171			$	—			$	—

Fixed maturities - HTM
Due less than one year	$	—			$	—			$	65,651			$	66,766

Due after 1 through 5 years	—				—				240,802				255,322

Due after 5 through 10 years	—				—				455,633				492,095

Due after 10 years	—				—				1,778,158				1,974,844

	$	—			$	—			$	2,540,244			$	2,789,027

RMBS – Non-Agency	—				—				66,987				71,972

CMBS	—				—				144,924				156,788

Other asset-backed securities	—				—				106,540				113,448

Total mortgage and asset-backed securities	$	—			$	—			$	318,451			$	342,208

Total fixed maturities - HTM	$	—			$	—			$	2,858,695			$	3,131,235

Gross unrealized losses	The following is an analysis of how long the AFS and HTM securities at December 31, 2014 and 2013 had been in a continual unrealized loss position:


	31-Dec-14	Less than 12 months								Equal to or greater
	(U.S. dollars in thousands)									than 12 months
		Fair Value				Gross				Fair Value				Gross
						Unrealized								Unrealized
						Losses								Losses
	Fixed maturities and short-term investments - AFS
	U.S. Government and Government-Related/Supported	$	251,091			$	(1,196	)		$	342,890			$	(5,603	)

	Corporate	1,337,470				(33,881		)		424,221				(15,754		)

	RMBS – Agency	134,535				(220		)		512,652				(10,563		)

	RMBS – Non-Agency	45,378				(1,358		)		202,700				(16,797		)

	CMBS	78,356				(385		)		169,065				(4,877		)

	CDO	249,803				(2,666		)		414,516				(24,503		)

	Other asset-backed securities	143,044				(2,813		)		57,544				(3,232		)

	U.S. States and political subdivisions of the States	32,187				(210		)		63,695				(994		)

	Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	624,346				(19,043		)		558,422				(43,251		)

	Total fixed maturities and short-term investments - AFS	$	2,896,210			$	(61,772	)		$	2,745,705			$	(125,574	)

	Total equity securities	$	191,193			$	(26,230	)		$	—			$	—

	Total fixed maturities - HTM	$	—			$	—			$	—			$	—




	31-Dec-13	Less than 12 months								Equal to or greater
	(U.S. dollars in thousands)									than 12 months
		Fair Value				Gross				Fair Value				Gross
						Unrealized								Unrealized
						Losses								Losses
	Fixed maturities and short-term investments - AFS
	U.S. Government and Government-Related/Supported	$	1,333,704			$	(30,474	)		$	44,158			$	(3,614	)

	Corporate	2,756,235				(59,497		)		513,106				(50,160		)

	RMBS – Agency	1,485,261				(50,362		)		169,704				(11,715		)

	RMBS – Non-Agency	14,204				(604		)		240,946				(30,522		)

	CMBS	432,820				(6,816		)		107,192				(8,957		)

	CDO	58,239				(217		)		574,613				(42,717		)

	Other asset-backed securities	196,639				(2,149		)		96,528				(6,691		)

	U.S. States and political subdivisions of the States	463,974				(23,124		)		64,324				(7,646		)

	Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	2,130,792				(56,866		)		306,873				(27,435		)

	Total fixed maturities and short-term investments - AFS	$	8,871,868			$	(230,109	)		$	2,117,444			$	(189,457	)

	Total equity securities	$	155,453			$	(17,470	)		$	—			$	—

Fixed maturities -HTM
Corporate	$	46,034			$	(941	)		$	642			$	(27	)

Non-U.S. Sovereign Government, Provincial, Supranational and Government-Related/Supported	—				—				11,894				(642		)

Total fixed maturities - HTM	$	46,034			$	(941	)		$	12,536			$	(669	)

Net investment income	Net investment income for the years ended December 31 is derived from the following sources:


	(U.S. dollars in thousands)	2014				2013				2012
	Fixed maturities, short term investments and cash equivalents - Excluding Life Funds Withheld Assets	$	809,964			$	982,275			$	1,046,255

	Fixed maturities, short term investments and cash equivalents - Life Funds Withheld Assets	129,575				—				—

	Equity securities and other investments	42,252				35,388				29,807

	Funds withheld	14,583				12,783				12,090

	Total gross investment income	$	996,374			$	1,030,446			$	1,088,152

	Investment expenses	(77,749		)		(72,730		)		(75,804		)
	Total net investment income	$	918,625			$	957,716			$	1,012,348

Net realized gains (losses)	The following represents an analysis of net realized gains (losses), the change in unrealized gains (losses) on investments and net realized and unrealized gains (losses) on investment related derivative instruments for the years ended December 31:


	(U.S. dollars in thousands)	2014				2013				2012
	Net realized gains (losses):
	Fixed maturities, short term investments, cash and cash equivalents - Excluding Life Funds Withheld Assets:
	Gross realized gains	$	119,817			$	129,479			$	163,328

	Gross realized losses on investments sold	(66,892		)		(84,703		)		(107,033		)
	OTTI on investments, net of amounts transferred to other comprehensive income	(12,341		)		(16,282		)		(74,245		)
	Net realized gains (losses)	$	40,584			$	28,494			$	(17,950	)

	Equity securities:
	Gross realized gains	$	96,260			$	29,402			$	42,009

	Gross realized losses on investments sold	(12,270		)		(3,185		)		(7,121		)
	OTTI on investments, net of amounts transferred to other comprehensive income	(10,944		)		(17		)		(3,746		)
	Net realized gains (losses)	$	73,046			$	26,200			$	31,142

	Other investments:
	Gross realized gains	$	31,830			$	46,934			$	11,610

	Gross realized losses on investments sold	(10,011		)		(13,851		)		(7,983		)
	OTTI on investments, net of amounts transferred to other comprehensive income	(12,458		)		—				(2,721		)

	Net realized gains (losses)	$	9,361			$	33,083			$	906

	Net realized gains (losses) on investments - Excluding Life Funds Withheld Assets	$	122,991			$	87,777			$	14,098

	Fixed maturities, short term investments, cash and cash equivalents - Life Funds Withheld Assets:
	Gross realized gains	$	7,926			$	—			$	—

	Gross realized losses on investments sold	(2,859		)		—				—

	Net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets	(9		)		—				—

	OTTI on investments, net of amounts transferred to other comprehensive income	(20,587		)		—				—

	Net realized gains (losses) on investments - Life Funds Withheld Assets	$	(15,529	)		$	—			$	—

	Net realized gains (losses) on investments	$	107,462			$	87,777			$	14,098

	Net realized and unrealized gains (losses) on investment related derivative instruments	$	20,121			$	6,367			$	(1,228	)

	Net realized gains (losses) on investments and net realized and unrealized gains (losses) on investment related derivative instruments	$	127,583			$	94,144			$	12,870

	Change in unrealized gains (losses):
	Fixed maturities – AFS - Excluding Life Funds Withheld Assets	$	360,463			$	(913,174	)		$	884,259

	Fixed maturities - AFS - Life Funds Withheld Assets	880,226				—				—

	Fixed maturities – HTM	(272,540		)		(175,817		)		221,647

	Equity securities	(32,577		)		105,163				44,361

	Affiliates and other investments	35,143				26,636				46,163

	Net change in unrealized gains (losses) on investments	$	970,715			$	(957,192	)		$	1,196,430

	Total net realized gains (losses) on investments, net realized and unrealized gains (losses) on investment related derivative instruments, and net change in unrealized gains (losses) on investments	$	1,098,298			$	(863,048	)		$	1,209,300

Credit loss impairments	The following table sets forth the amount of credit loss impairments on fixed income securities held by the Company as of the dates or for the periods indicated, for which a portion of the OTTI loss was recognized in OCI, and the corresponding changes in such amounts.


	Credit Loss Impairments	2014				2013
	(U.S. dollars in thousands)
	Opening balance at beginning of indicated period	$	174,805			$	268,708

	Credit loss impairment recognized in the current period on securities not previously impaired	3,907				806

	Credit loss impairments previously recognized on securities which matured, paid down, prepaid or were sold during the period	(42,671		)		(92,167		)
	Credit loss impairments previously recognized on securities impaired to fair value during the period	—				—

	Additional credit loss impairments recognized in the current period on securities previously impaired	4,185				11,182

	Accretion of credit loss impairments previously recognized due to an increase in cash flows expected to be collected	(8,284		)		(13,724		)
	Closing balance at end of indicated period	$	131,942			$	174,805

Investments_in_Affiliates_Tabl

Investments in Affiliates (Tables)	12 Months Ended
	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	Investments in affiliates comprised the following at December 31, 2014 and 2013:


	(U.S. dollars in thousands)	2014		2013
	Investment fund affiliates	$	1,219,138	$	1,042,072

	Operating affiliates	418,482		328,871

	Total investment affiliates	$	1,637,620	$	1,370,943

Investment fund affiliates
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	The Company’s equity investment in investment fund affiliates and equity in net income (loss) from such affiliates as well as certain summarized financial information of the investee as a whole (shown as “Combined Funds”) are included below:


	Year Ended December 31, 2014	XL Group Investment						Combined
	(U.S. dollars in thousands, except percentages)	Carrying		Equity in		Weighted		Funds
		Value		Net Income		Average XL
				(Loss) for		Percentage
				the Year		Ownership		Total Net Assets
								(Estimated) (1)
	Alternative Funds (2):
	Arbitrage	$	134,400	$	12,060	11	%	$	1,224,526

	Directional	536,470		32,196		9.2	%	5,865,247

	Event Driven (3)	300,168		21,030		3.1	%	9,703,973

	Multi-Style	52,122		1,751		4.1	%	1,278,410

	Total alternative funds	$	1,023,160	$	67,037	5.7	%	$	18,072,156

	Private Investment Funds (2):	195,978		28,779		17.7	%	1,105,776

	Total Investment Fund Affiliates	$	1,219,138	$	95,816	6.4	%	$	19,177,932

	Year Ended December 31, 2013
	Alternative Funds (2):
	Arbitrage	$	158,096	$	4,358	3.7	%	$	4,328,748

	Directional	434,652		42,492		8.3	%	5,235,690

	Event Driven (3)	274,380		61,551		2.9	%	9,309,163

	Multi-Style	374		48		15.5	%	2,410

	Total alternative funds	$	867,502	$	108,449	4.6	%	$	18,876,011

	Private Investment Funds (2):	174,570		29,942		19.6	%	890,815

	Total Investment Fund Affiliates	$	1,042,072	$	138,391	5.3	%	$	19,766,826

	____________

	-1	Total estimated net assets are generally as at November 30 for alternative fund affiliates and September 30 for private investment fund affiliates.

	-2	The Company generally records its alternative fund affiliates on a one-month lag and its private investment fund affiliates on a three-month lag.

	-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	The Company’s equity investment in operating affiliates and equity in net income (loss) from such affiliates as well as certain summarized financial information of the investee as a whole are included below:


	Year ended December 31, 2014	XL Group Investment				Combined Investee Summarized
	(U.S. dollars in thousands)					Financial Data (Estimated) (1)
		Carrying		Equity in		Total			Total		Total		Net Income
		Value		Net Income		Assets			Liabilities		Revenue		(Loss)
				(Loss) for							(Loss)
				the Year
	Other strategic operating affiliates	$	317,216	$	50,132	$	4,679,395		$	3,691,173	$	1,075,935	$	152,122

	Investment manager affiliates (2)	101,266		57,086		850,666			101,088		579,524		476,841

	Total operating affiliates	$	418,482	$	107,218	$	5,530,061		$	3,792,261	$	1,655,459	$	628,963

	Year ended December 31, 2013
	Other strategic operating affiliates	266,796		41,160		2,646,987			1,888,879		902,522		125,625

	Investment manager affiliates (2)	62,075		78,644		922,348			92,574		813,587		710,412

	Total operating affiliates	$	328,871	$	119,804	$	3,569,335		$	1,981,453	$	1,716,109	$	836,037

	____________

	-1	The Company generally records its operating affiliates on a three-month lag. Estimated assets and liabilities are generally at September 30, 2014 and 2013, respectively.

	-2	During the years ended December 31, 2014 and 2013, the Company received distributions from its Investment Manager Affiliates of approximately $60.3 million and $28.3 million, respectively.

Other_Investments_Tables

Other Investments (Tables)	12 Months Ended
Other Investments (Tables)	Dec. 31, 2014
Investments, All Other Investments [Abstract]
Components of other investments	Other investments comprised the following at December 31, 2014 and 2013:


	Year ended December 31,	2014		2013
	(U.S. dollars in thousands)	2014		2013
	Alternative Investment Funds:
	Arbitrage	$	179,821	$	158,220
	Arbitrage	$	179,821	$	158,220
	Directional	336,082		357,469
	Directional	336,082		357,469
	Event Driven	56,238		56,873
	Event Driven	56,238		56,873
	Multi-Style	68,706		72,625
	Multi-Style	68,706		72,625
	Total alternative funds	$	640,847	$	645,187
	Total alternative funds	$	640,847	$	645,187
	Private investment funds	129,243		94,064
	Private investment funds	129,243		94,064
	Overseas deposits	92,223		111,302
	Overseas deposits	92,223		111,302
	Structured transactions	350,563		294,048
	Structured transactions	350,563		294,048
	Other	35,563		20,029
	Other	35,563		20,029
	Total other investments	$	1,248,439	$	1,164,630
	Total other investments	$	1,248,439	$	1,164,630
Analysis of net realized and unrealized gains	The following represents an analysis of the net realized gains for the indicated years ended December 31, and the net unrealized gains as of December 31, on the Company’s alternative investment funds and private equity funds:


	Year ended December 31,	Net Unrealized Gains				Net Realized Gains (Losses)
	(U.S. dollars in thousands)	(Losses)				Net Realized Gains (Losses)
		2014		2013		2014		2013		2012
	Alternative investment funds	$	188,674	$	158,825	$	6,685	$	30,858	$	(2,153	)
	Alternative investment funds	$	188,674	$	158,825	$	6,685	$	30,858	$	(2,153	)
	Private investment funds	42,604		44,027		13,275		4,331		257
	Private investment funds	42,604		44,027		13,275		4,331		257
	Total	$	231,278	$	202,852	$	19,960	$	35,189	$	(1,896	)
	Total	$	231,278	$	202,852	$	19,960	$	35,189	$	(1,896	)

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of goodwill & intangible assets	The following table presents an analysis of intangible assets broken down between goodwill, intangible assets with an indefinite life and intangible assets with a definite life for the years ended December 31, 2014, 2013 and 2012:


	(U.S. dollars in thousands)	Goodwill			Intangible		Intangible			Total
					assets with an		assets with a
					indefinite life		definite life
	Balance at December 31, 2011	$	391,498		$	15,366	$	457		$	407,321

	Amortization	—			—		(178		)	(178		)

	Foreign Currency Translation	1,384			—		—			1,384

	Balance at December 31, 2012	$	392,882		$	15,366	$	279		$	408,527

	Amortization	—			—		(279		)	(279		)

	Foreign Currency Translation	3,363			—		—			3,363

	Balance at December 31, 2013	$	396,245		$	15,366	$	—		$	411,611

	Additions	25,159			—		18,500			43,659

	Amortization	—			—		(1,850		)	(1,850		)

	Foreign Currency Translation	(5,468		)	—		—			(5,468		)

	Balance at December 31, 2014	$	415,936		$	15,366	$	16,650		$	447,952

Reinsurance_Tables

Reinsurance (Tables)	12 Months Ended
Reinsurance (Tables)	Dec. 31, 2014
Reinsurance Disclosures [Abstract]
Effect of reinsurance	The effect of reinsurance and retrocessional activity on premiums written and earned from property and casualty operations is shown below:


	(U.S. dollars in thousands)	Premiums Written										Premiums Earned
		Year Ended December 31,										Year Ended December 31,
		2014				2013			2012			2014			2013			2012
	Direct	$	5,450,868			$	5,050,953		$	4,733,516		$	5,173,403		$	4,966,207		$	4,604,323
	Direct	$	5,450,868			$	5,050,953		$	4,733,516		$	5,173,403		$	4,966,207		$	4,604,323
	Assumed	2,310,621				2,365,839			2,441,612			2,343,329			2,363,261			2,393,490
	Assumed	2,310,621				2,365,839			2,441,612			2,343,329			2,363,261			2,393,490
	Ceded	(1,994,280		)		(1,512,810		)	(1,218,109		)	(1,799,294		)	(1,315,369		)	(1,231,835		)
	Net	$	5,767,209			$	5,903,982		$	5,957,019		$	5,717,438		$	6,014,099		$	5,765,978
	Net	$	5,767,209			$	5,903,982		$	5,957,019		$	5,717,438		$	6,014,099		$	5,765,978
Analysis of losses, loss expenses and future policy benefit reserves recoverables	The following table presents an analysis of total unpaid losses and loss expenses and future policy benefit reserves recoverable for the year ended December 31:


	(U.S. dollars in thousands)	2014				2013
	P&C Operations	$	3,411,526			$	3,414,735
	P&C Operations	$	3,411,526			$	3,414,735
	Corporate and Other	17,842				20,495
	Corporate and Other	17,842				20,495
	Total unpaid losses and loss expenses recoverable	$	3,429,368			$	3,435,230
	Total unpaid losses and loss expenses recoverable	$	3,429,368			$	3,435,230
Ceded credit risk by reinsurer	The following is an analysis of the total recoverable and reinsurance balances receivable, net of collateral held, at December 31, 2014, by reinsurers owing 3% or more of such total:


	Name of Reinsurer	Reinsurer Financial Strength Rating		% of Total
	Munich Reinsurance Co.	AA-/Stable		10.5	%
	Swiss Reinsurance Co.	AA-/Stable		8.8	%
	Transatlantic Reinsurance Co.	A+/Stable		8.1	%
	Swiss Re Europe S.A.	AA-/Stable		7.7	%
	Arch Reinsurance Co.	A+/Stable		6.3	%
	Lloyd's Syndicates	A+/Stable		5.1	%
	AXIS Reinsurance Co.	A+/Stable		4.6	%
Ratings profile of reinsurers	The following table sets forth the ratings profile of the reinsurers that support the unpaid loss and loss expense recoverable and reinsurance balances receivable, net of collateral, at December 31, 2014:


	Reinsurer Financial Strength Rating	% of Total
	AAA	0.1	%
	AA	42	%
	A	50.4	%
	BBB	0.4	%
	Captives	5.4	%
	Other	1.7	%
	Total	100	%

Losses_and_Loss_Expenses_Table

Losses and Loss Expenses (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting Information [Line Items]
Components of reserves	Unpaid losses and loss expenses for the indicated years ended December 31 are comprised of:


	(U.S. dollars in thousands)	2014				2013
	Reserve for reported losses and loss expenses	$	7,461,444			$	8,149,501

	Reserve for losses incurred but not reported	11,891,799				12,331,564

	Unpaid losses and loss expenses	$	19,353,243			$	20,481,065

Components of incurred losses and loss expenses	Net losses and loss expenses incurred for the years indicated are comprised of:


	(U.S. dollars in thousands)	2014				2013			2012
	Loss and loss expenses payments	$	4,499,642			$	4,496,802		$	4,673,998

	Change in unpaid losses and loss expenses	(514,406		)		(71,901		)	(297,660		)
	Change in unpaid losses and loss expenses recoverable	(48,536		)		(24,774		)	279,900

	Paid loss recoveries	(678,307		)		(668,663		)	(890,756		)
	Net losses and loss expenses incurred	$	3,258,393			$	3,731,464		$	3,765,482

Reserve roll forward	The following table represents an analysis of the Company’s paid and unpaid losses and loss expenses incurred and a reconciliation of the beginning and ending unpaid losses and loss expenses for the years indicated:


	(U.S. dollars in thousands)	2014				2013			2012
	Unpaid losses and loss expenses at the beginning of the year	$	20,481,065			$	20,484,121		$	20,613,901

	Unpaid losses and loss expenses recoverable	3,414,735				3,361,703			3,629,940

	Net unpaid losses and loss expenses at the beginning of the year	$	17,066,330			$	17,122,418		$	16,983,961

	Increase (decrease) in net losses and loss expenses incurred in respect of losses occurring in:
	Current year	3,513,469				4,021,353			4,081,376

	Prior year	(255,076		)		(289,889		)	(315,894		)
	Total net incurred losses and loss expenses	$	3,258,393			$	3,731,464		$	3,765,482

	Exchange rate effects	(561,673		)		40,587			156,217

	Less net losses and loss expenses paid in respect of losses occurring in:
	Current year	381,008				425,254			416,844

	Prior year	3,440,327				3,402,885			3,366,398

	Total net paid losses	$	3,821,335			$	3,828,139		$	3,783,242

	Net unpaid losses and loss expenses at the end of the year	15,941,715				17,066,330			17,122,418

	Unpaid losses and loss expenses recoverable	3,411,528				3,414,735			3,361,703

	Unpaid losses and loss expenses at the end of the year	$	19,353,243			$	20,481,065		$	20,484,121

Components of prior year development	The following table presents the net (favorable) adverse prior year loss development of the Company’s loss and loss expense reserves for its property and casualty operations by operating segment for each of the years indicated:


	(U.S. dollars in thousands)	2014				2013			2012
	Insurance segment	$	(99,762	)		$	(102,039	)	$	(140,066	)
	Reinsurance segment	(155,314		)		(187,850		)	(175,828		)
	Total	$	(255,076	)		$	(289,889	)	$	(315,894	)
Asbestos and environmental related claims rollforward	A reconciliation of the opening and closing unpaid losses and loss expenses related to discontinued asbestos and run-off environmental exposure claims for the years indicated is as follows:


	Year ended December 31,	2014				2013			2012
	(U.S. dollars in thousands)
	Net unpaid losses and loss expenses at beginning of year	$	80,435			$	78,315		$	77,778

	Net incurred losses and loss expenses	8,903				6,257			6,558

	Less net paid losses and loss expenses	7,922				4,137			6,021

	Net increase (decrease) in unpaid losses and loss expenses	$	981			$	2,120		$	537

	Net unpaid losses and loss expenses at end of year	81,416				80,435			78,315

	Unpaid losses and loss expenses recoverable at end of year	100,537				115,090			123,799

	Gross unpaid losses and loss expenses at end of year	$	181,953			$	195,525		$	202,114

Schedule of open claims files for potential asbestos and environmental claims	The development of the number of open claim files for potential discontinued asbestos and run-off environmental claims, including precautionary claims, is as follows:


		Asbestos			Environmental
		Claims			Claims
	Total number of claims outstanding at December 31, 2011	1,038			362

	New claims reported in 2012	236			60

	Claims resolved in 2012	(201	)		(68	)
	Total number of claims outstanding at December 31, 2012	1,073			354

	New claims reported in 2013	178			34

	Claims resolved in 2013	(154	)		(50	)
	Total number of claims outstanding at December 31, 2013	1,097			338

	New claims reported in 2014	456			190

	Claims resolved in 2014	(154	)		(69	)
	Total number of claims outstanding at December 31, 2014	1,399			459

Insurance Segment [Member]
Segment Reporting Information [Line Items]
Components of prior year development	The following table summarizes the net (favorable) adverse prior year development by line of business relating to the Insurance segment for the indicated years ended December 31:


	(U.S. dollars in thousands)	2014				2013			2012
	Property	$	(57,470	)		$	(46,387	)	$	(46,735	)
	Casualty	38,413				(21,829		)	(61,630		)

	Professional	17,094				75,045			(106,360		)

	Specialty	(82,756		)		(140,740		)	(61,755		)
	Other	(15,043		)		31,872			136,414

	Total	$	(99,762	)		$	(102,039	)	$	(140,066	)
Reinsurance Segment [Member]
Segment Reporting Information [Line Items]
Components of prior year development	The following table summarizes the net (favorable) adverse prior year development by line of business relating to the Reinsurance segment for the indicated years ended December 31:


	(U.S. dollars in thousands)	2014				2013			2012
	Property and other short-tail lines	$	(85,324	)		$	(136,912	)	$	(107,613	)
	Casualty and other	(69,990		)		(50,938		)	(68,215		)
	Total	$	(155,314	)		$	(187,850	)	$	(175,828	)

Future_Policy_Benefit_Reserve_

Future Policy Benefit Reserve (Tables)	12 Months Ended
	Dec. 31, 2014
Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract]
Components of future policy benefit reserve	Future policy benefit reserves are comprised of the following:


	Year ended December 31	2014		2013
	(U.S. dollars in thousands)
	Traditional Life	$	789,133	$	827,341

	Annuities	3,918,066		3,976,475

	Total future policy benefit reserves	$	4,707,199	$	4,803,816

Funds_Withheld_on_Life_Retroce1

Funds Withheld on Life Retrocession Arrangements (Tables)	12 Months Ended
	Dec. 31, 2014
Funds Withheld on Life Retrocession Arrangements Disclosure [Abstract]
Funds withheld on life retrocession arrangements	Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable) for the year ended December 31, 2014 are comprised of:


	(U.S. dollars in thousands)	2014
	Assets held on a funds withheld basis relating to the Life Retro Arrangements	$	5,420,694

	Reinsurance recoverable from GCLR	(4,265,678		)
	Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable)	$	1,155,016

Notes_Payable_and_Debt_and_Fin1

Notes Payable and Debt and Financing Arrangements (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Financing structure	At December 31, the Company’s financing structure, which includes senior unsecured notes, bank and loan facilities available from a variety of sources, including commercial banks, and letter of credit facilities was as follows:


	(U.S. dollars in thousands)	2014						2013
		Commitment/			In Use/			Commitment/		In Use/
		Debt			Outstanding (1)			Debt		Outstanding (1)
	Debt:
	5-year revolver expiring 2018	$	1,000,000		$	—		$	1,000,000	$	—

	5.25% Senior Notes due 2014	—			—			600,000		599,346

	2.30% Senior Notes due 2018	300,000			297,344			300,000		296,683

	5.75% Senior Notes due 2021	400,000			397,092			400,000		396,661

	6.375% Senior Notes due 2024	350,000			348,920			350,000		348,811

	6.25% Senior Notes due 2027	325,000			323,062			325,000		322,905

	5.25% Senior Notes due 2043	300,000			296,162			300,000		296,030

	Total debt	$	2,675,000		$	1,662,580		$	3,275,000	$	2,260,436

	Adjustment to carrying value – impact of fair value hedges				—					2,767

	Total debt carrying value	$	2,675,000		$	1,662,580		$	3,275,000	$	2,263,203

	Letters of Credit:
	Total letters of credit	$	3,575,000		$	1,790,561		$	3,575,000	$	1,895,425


	____________

	-1	“In Use” and “Outstanding” data represent December 31, 2014 and 2013 accreted values.
Credit facilities	The Company’s letter of credit facilities and revolving credit facilities at December 31 were as follows:


	(U.S. dollars in thousands)	2014 (1)			2013 (1)
	Revolving credit facility (2)	$	1,000,000		$	1,000,000

	Available letter of credit facilities – commitments (3)	$	3,575,000		$	3,575,000

	Available letter of credit facilities – in use	$	1,790,561		$	1,895,425

	Collateralized by certain assets of the Company’s investment portfolio	66.2		%	67.6		%

	____________

	-1	At December 31, 2014, there were eight available letter of credit facilities; at December 31, 2013, there were seven available letter of credit facilities.

	-2	At December 31, 2014 and 2013, the revolving credit available under the Syndicated Credit Agreements (as defined below) and under the December 9, 2011 unsecured credit agreement, respectively, was unutilized. The 2013 Citi Agreements (as defined below) provide for issuance of letters of credit and revolving credit loans in an aggregate amount of up to $575 million. At December 31, 2014, $575 million of letters of credit were issued under the 2013 Citi Agreements and therefore such amount is not included here.

	-3	The Company has the option to increase the size of the facilities under the Syndicated Credit Agreements by an additional $500 million across such facilities. The Company also has the option to increase the maximum amount of the letters of credit and revolving credit loans available under the 2013 Citi Agreements, with the lender's and issuing lender's consent.

Derivative_Instruments_Tables

Derivative Instruments (Tables)	12 Months Ended
Derivative Instruments (Tables)	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of location and gross amounts of derivative fair values in the consolidated balance sheets	The following table summarizes information on the location and gross amounts of derivative fair values contained in the consolidated balance sheets at December 31, 2014 and 2013:


	(U.S. dollars in thousands)	2014												2013
		Asset			Asset			Liability			Liability			Asset		Asset		Liability		Liability
		Derivative			Derivative			Derivative			Derivative			Derivative		Derivative		Derivative		Derivative
		Notional			Fair			Notional			Fair			Notional		Fair		Notional		Fair
		Amount			Value (1)			Amount			Value (1)			Amount		Value (1)		Amount		Value (1)
	Derivatives designated as hedging instruments:
	Foreign exchange contracts	$	2,300,609		$	121,862		$	302,211		$	2,936		$	1,005,610	$	26,098	$	2,572,227	$	70,462
	Foreign exchange contracts	$	2,300,609		$	121,862		$	302,211		$	2,936		$	1,005,610	$	26,098	$	2,572,227	$	70,462
	Total derivatives designated as hedging instruments	$	2,300,609		$	121,862		$	302,211		$	2,936		$	1,005,610	$	26,098	$	2,572,227	$	70,462
	Total derivatives designated as hedging instruments	$	2,300,609		$	121,862		$	302,211		$	2,936		$	1,005,610	$	26,098	$	2,572,227	$	70,462
	Derivatives not designated as hedging instruments:
	Investment Related Derivatives:
	Interest rate exposure	$	394,597		$	206		$	20,782		$	51		$	30,702	$	266	$	10,259	$	8
	Interest rate exposure	$	394,597		$	206		$	20,782		$	51		$	30,702	$	266	$	10,259	$	8
	Foreign exchange exposure	7,385			403			288,376			4,724			17,497		12		50,614		680
	Foreign exchange exposure	7,385			403			288,376			4,724			17,497		12		50,614		680
	Credit exposure	2,408			165			14,270			9,836			—		—		340,020		15,128
	Credit exposure	2,408			165			14,270			9,836			—		—		340,020		15,128
	Financial market exposure	46,145			360			33,670			34			58,232		1,111		14,821		77
	Financial market exposure	46,145			360			33,670			34			58,232		1,111		14,821		77
	Financial Operations Derivatives: (2)
	Credit exposure	—			—			—			—			—		—		44,234		4,190
	Credit exposure	—			—			—			—			—		—		44,234		4,190
	Other Non-Investment Derivatives:
	Credit exposure	31,060			60			—			—			—		—		—		—
	Credit exposure	31,060			60			—			—			—		—		—		—
	Guaranteed minimum income benefit contract	46,249			13,603			46,249			13,603			—		—		53,564		14,940
	Guaranteed minimum income benefit contract	46,249			13,603			46,249			13,603			—		—		53,564		14,940
	Modified coinsurance funds withheld contract (3)	64,947			—			5,401,278			—			66,369		—		—		—
	Modified coinsurance funds withheld contract (3)	64,947			—			5,401,278			—			66,369		—		—		—
	Total derivatives not designated as hedging instruments	$	592,791		$	14,797		$	5,804,625		$	28,248		$	172,800	$	1,389	$	513,512	$	35,023
	Total derivatives not designated as hedging instruments	$	592,791		$	14,797		$	5,804,625		$	28,248		$	172,800	$	1,389	$	513,512	$	35,023
	____________

	-1	Derivative instruments in an asset or liability position are included within Other assets or Other liabilities, respectively, in the balance sheets on a net basis where the Company has both a legal right of offset and the intention to settle the contracts on a net basis.

	-2	Financial operations derivatives represent interests in variable interest entities as described in Note 18, “Variable Interest Entities".

	-3	The fair value movements in derivative assets and liabilities relating to modified coinsurance funds withheld contracts are included within the associated asset or liability at each period end on the face of the balance sheets. Notional amounts associated with reinsurance agreements under which the Company assumes reinsurance risk are recorded as asset derivative notional amounts. Notional amounts associated with the Life Retro Arrangements under which the Company cedes reinsurance risk are recorded as liability derivative notional amounts. Included in the liability derivative notional amount at December 31, 2014 is the cumulative net realized and unrealized loss on life retrocession embedded derivative of $450.8 million.
Summary of gross and net amounts of derivative fair values and associated collateral	The following table summarizes information on the gross and net amounts of derivative fair values and associated collateral received related to derivative assets or paid relating to derivative liabilities contained in the consolidated balance sheets at December 31, 2014 and 2013:


											Gross Amounts Not Offset in the Balance Sheets
	31-Dec-14	Gross Amounts Recognized in the Balance Sheets			Gross Amounts Offset in the Balance Sheets			Net Amounts in the Balance Sheets			Financial Instruments			Cash Collateral		Net Amounts
	(U.S. dollars in thousands)	Gross Amounts Recognized in the Balance Sheets			Gross Amounts Offset in the Balance Sheets			Net Amounts in the Balance Sheets			Financial Instruments			Cash Collateral		Net Amounts
	Derivative Assets	$	136,659		$	696		$	135,963		$	—		$	78,580	$	57,383
	Derivative Assets	$	136,659		$	696		$	135,963		$	—		$	78,580	$	57,383
	Derivative Liabilities	$	31,184		$	696		$	30,488		$	—		$	—	$	30,488
	Derivative Liabilities	$	31,184		$	696		$	30,488		$	—		$	—	$	30,488

	31-Dec-13
	(U.S. dollars in thousands)
	Derivative Assets	$	27,487		$	1,342		$	26,145		$	—		$	—	$	26,145
	Derivative Assets	$	27,487		$	1,342		$	26,145		$	—		$	—	$	26,145
	Derivative Liabilities	$	105,485		$	1,342		$	104,143		$	—		$	19,847	$	84,296
	Derivative Liabilities	$	105,485		$	1,342		$	104,143		$	—		$	19,847	$	84,296
Total impact on earnings related to derivative instruments	The following table provides the total impact on earnings relating to derivative instruments formally designated as fair value hedges along with the impacts of the related hedged items for the years indicated:


	Derivatives Designated as Fair Value Hedges	Hedged Items – Amount of Gain/(Loss) Recognized in Income Attributable to Risk
	(U.S. dollars in thousands)	Gain/(Loss) Recognized in Income on Derivative			Deposit			Fixed			Ineffective Portion of Hedging Relationship – Gain/(Loss)
					Liabilities			Maturity
								Investments
	Year Ended December 31, 2014
	Interest rate exposure	$	—
	Interest rate exposure	$	—
	Foreign exchange exposure	(15,663		)
	Total	$	(15,663	)	$	—		$	15,407		$	(256	)
	Total	$	(15,663	)	$	—		$	15,407		$	(256	)
	Year Ended December 31, 2013
	Interest rate exposure	$	—
	Interest rate exposure	$	—
	Foreign exchange exposure	(22,568		)
	Total	$	(22,568	)	$	—		$	23,065		$	497
	Total	$	(22,568	)	$	—		$	23,065		$	497
	Year Ended December 31, 2012
	Interest rate exposure	$	1,813
	Interest rate exposure	$	1,813
	Foreign exchange exposure	(24,183		)
	Total	$	(22,370	)	$	(6,182	)	$	23,967		$	(4,585	)
	Total	$	(22,370	)	$	(6,182	)	$	23,967		$	(4,585	)
Summary of fair value hedges that have been settled and their impact on results during the year	A summary of the fair value hedges that have been settled and their impact on results during the indicated years ended December 31 as well as the remaining balance of fair value hedges and average years remaining to maturity are shown below:


	Settlement of Fair Value Hedges – Summary	Fair Value Hedges –						Fair Value Hedges –
	(U.S. dollars in thousands, except years)	Notes Payable and Debt						Deposit Liabilities
		December 31,						December 31,
		2014			2013			2014			2013
	Cumulative reduction to interest expense	$	21,624		$	18,856		$	95,333		$	37,382
	Cumulative reduction to interest expense	$	21,624		$	18,856		$	95,333		$	37,382
	Remaining balance	$	—		$	2,767		$	137,862		$	195,814
	Remaining balance	$	—		$	2,767		$	137,862		$	195,814
	Weighted average years remaining to maturity	0			0.7			23.2			22.7
	Weighted average years remaining to maturity	0			0.7			23.2			22.7
Weighted average US dollar equivalent of foreign denominated net assets that were hedge and resultant gain (loss)	The following table provides the weighted average U.S. dollar equivalent of foreign denominated net assets that were hedged and the resulting derivative gain (loss) that was recorded in the foreign currency translation adjustment, net of tax, account within AOCI for the year ended December 31, 2014 and 2013.


	Derivative Instruments Designated as Hedges of the Net Investment in a Foreign Operation – Summary	2014			2013
	(U.S. dollars in thousands)	2014			2013
	Weighted average of U.S. dollar equivalent of foreign denominated net assets	$	2,384,508		$	2,648,137
		$	2,384,508		$	2,648,137
	Derivative gains (losses) (1)	$	120,643		$	(27,392	)
	Derivative gains (losses) (1)	$	120,643		$	(27,392	)

	____________

	-1	Derivative gains (losses) from derivative instruments designated as hedges of the net investment in a foreign operation are recorded in the cumulative translation adjustment account within AOCI for each period.
Total impact on earnings relating to derivative instruments not formally designated as hedging	The following table provides the total impact on earnings relating to derivative instruments not formally designated as hedging instruments under authoritative accounting guidance and from the ineffective portion of fair value hedges. The impacts are all recorded through Net realized and unrealized gains (losses) on derivatives in the income statement for the years ended December 31, 2014, 2013 and 2012:


	Net Realized and Unrealized Gains (Losses) on Derivative Instruments	2014			2013			2012
	(U.S. dollars in thousands)	2014			2013			2012
	Investment Related Derivatives:
	Interest rate exposure	$	15,959		$	5,065		$	4,394
	Interest rate exposure	$	15,959		$	5,065		$	4,394
	Foreign exchange exposure	3,351			(948		)	(1,084		)
	Foreign exchange exposure	3,351			(948		)	(1,084		)
	Credit exposure	400			(4,052		)	(7,611		)
	Credit exposure	400			(4,052		)	(7,611		)
	Financial market exposure	411			6,302			3,073
	Financial market exposure	411			6,302			3,073
	Financial Operations Derivatives:
	Credit exposure	5,023			(2,437		)	10,511
	Credit exposure	5,023			(2,437		)	10,511
	Other Non-Investment Derivatives:
	Credit exposure	—			—			—
	Credit exposure	—			—			—
	Guaranteed minimum income benefit contract	2,257			10,457			(2,906		)
	Guaranteed minimum income benefit contract	2,257			10,457			(2,906		)
	Modified coinsurance funds withheld contract	2,741			(7,086		)	3,429
	Modified coinsurance funds withheld contract	2,741			(7,086		)	3,429
	Total derivatives not designated as hedging instruments	$	30,142		$	7,301		$	9,806
	Total derivatives not designated as hedging instruments	$	30,142		$	7,301		$	9,806
	Amount of gain (loss) recognized in income from ineffective portion of fair value hedges	(256		)	497			(4,585		)
		(256		)	497			(4,585		)
	Net realized and unrealized gains (losses) on derivative instruments	$	29,886		$	7,798		$	5,221
		$	29,886		$	7,798		$	5,221
	Net realized and unrealized gains (losses on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets	$	(488,222	)	$	—		$	—
		$	(488,222	)	$	—		$	—
Components of life retrocession embedded derivatives	The value of the life retrocession embedded derivative includes the interest income, realized and unrealized gains and losses on Life Funds Withheld Assets and certain related expenses subsequent to May 30, 2014 as follows:


	Components of Life Retrocession Embedded Derivative and Derivative Instruments - Life Funds Withheld Assets:
	(U.S. dollars in thousands)	2014
	Interest income	$	(134,634	)
	Realized and unrealized gains (losses) on Life Funds Withheld Assets	(318,065		)
	Other	1,868
	Other	1,868
	Net realized and unrealized gains (losses) on life retrocession embedded derivative	$	(450,831	)
	Net adjustments related to future policy benefit reserves, net of tax	$	(21,786	)
	Net realized and unrealized gains (losses) on derivative instruments - Life Funds Withheld Assets	$	(15,605	)
	Net realized and unrealized gains (losses) on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets	$	(488,222	)
Summary of contingent credit features	The aggregate fair value of all derivative agreements containing such rating downgrade provisions that were in a liability position and any collateral posted under these agreements at December 31 for the years indicated were as follows:


	Contingent Credit Features - Summary:	2014			2013
	(U.S. dollars in thousands)	2014			2013
	Aggregate fair value of derivative agreements with downgrade provisions in a net liability position	$	5,770		$	47,703
		$	5,770		$	47,703
	Collateral posted to counterparty	$	—		$	13,260
	Collateral posted to counterparty	$	—		$	13,260

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Broker credit risk	During the three years ended December 31, 2014, 2013 and 2012, P&C gross written premiums generated from or placed by the below companies individually accounted for more than 10% of the Company’s consolidated gross written premiums from P&C operations, as follows:


	(Percentage of consolidated gross written premiums from P&C operations)	2014			2013			2012
	AON Corporation and subsidiaries	18	%		21	%		22	%
	Marsh & McLennan Companies	20	%		23	%		21	%
	Willis Group and subsidiaries	11	%		13	%		11	%
Future minimum lease payments - operating	Future minimum rental commitments under existing operating leases are expected to be as follows:


	Year Ended December 31,
	(U.S. dollars in thousands)
	2015	$	36,949

	2016	32,027

	2017	28,933

	2018	25,156

	2019	24,086

	2020-2031	73,269

	Total minimum future rentals	$	220,420

Future minimum lease payments - capital lease	The future minimum lease payments in the aggregate are expected to be $191.4 million and annually for the next five years are as follows:


	Year Ended December 31,
	(U.S. dollars in thousands)
	2015	$	12,095

	2016	12,398

	2017	12,708

	2018	13,025

	2019	13,351

	2020-2028	127,787

	Total minimum future lease payments	$	191,364

Financial guarantee exposure summary	A summary of the Company's outstanding financial guarantee exposures for the years indicated is as follows:


	Financial Guarantee Exposure Summary	2014				2013
	(U.S. dollars in thousands except number of contracts and term to maturity)
	Opening number of financial guarantee contracts	3				4

	Number of financial guarantee contracts matured, prepaid or commuted during the period	(1		)		(1		)
	Closing number of financial guarantee contracts	2				3

	Principal outstanding	$	80,813			$	108,255

	Interest outstanding	$	—			$	—

	Aggregate exposure outstanding	$	80,813			$	108,255

	Total gross claim liability recorded	$	—			$	—

	Total unearned premiums and fees recorded	$	—			$	134

	Weighted average contractual term to maturity in years	25.2				26

Share_Capital_Tables

Share Capital (Tables)	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Summary of ordinary shares issued and outstanding	The following table is a summary of ordinary shares issued and outstanding:


	(in thousands)	2014			2013
	Balance – beginning of year	278,253			298,682

	Exercise of options	424			927

	Net issuance of restricted shares	1,246			1,240

	Share buybacks (1)	(24,740	)		(22,596	)
	Balance – end of year	255,183			278,253

	____________

	-1	Includes share buybacks associated with authorized share buyback programs as well as purchases related to satisfying tax withholding obligations of employees in connection with the vesting of restricted shares granted under the Company’s equity compensation programs.
Weighted average option pricing assumptions	The fair value of each option grant is estimated on the date of grant using the Black-Scholes option pricing model with the following weighted average assumptions:


		2014			2013			2012
	Dividend yield	2	%		2	%		1.9	%
	Risk free interest rate	1.81	%		1.14	%		1.15	%
	Volatility	34	%		37	%		46	%
	Expected lives	6.0 years			6.0 years			6.0 years

Summary of options and options activity	The following is a summary of the activity in the stock option plans for the indicated years ended December 31:


	(In thousands except for weighted average grant date fair value)	2014				2013				2012
	Options granted to purchase ordinary shares under directors and employees incentive compensation plans - in thousands	1,025				1,047				1,209

	Weighted average grant date fair value	$	8.6			$	8.34			$	7.65

	Total intrinsic value of stock options exercised	$	7,499			$	16,076			$	3,357

	Options exercised during the year - in thousands	424				927				383

	Compensation expense related to stock option plans	$	9,961			$	8,294			$	7,716

	Estimated tax benefit (charge) related to stock option plans	$	(2	)		$	50			$	26

	The following is a summary of the stock options outstanding at December 31, 2014, and related activity for the year then ended:


		Number of Shares (*in thousands*)			Weighted				Weighted		Aggregate
					Average				Average		Intrinsic
					Exercise				Remaining		Value
					Price				Contractual		(in thousands)
									Term
	Outstanding – beginning of year	11,123			$	36.91			4.8 years		$	74,927

	Granted	1,025			30.42

	Exercised	(424	)		15.04

	Canceled/Expired	(1,199	)		78.46

	Outstanding – end of year	10,525			$	32.42			4.8 years		$	86,690

	Options exercisable	8,400			$	33.53			3.9 years		$	73,153

	Available for grant (1)	10,316


	(1) Available for grant includes shares that may be granted as either stock options, restricted stock, restricted stock units or performance units.
Summary of restricted stock and non-vested restricted stock activity	A summary of the restricted stock awards issued under the 1991 Performance Incentive Program and the Directors Stock and Option Plan for the indicated years ended December 31 is as follows:


	(In thousands except for weighted average grant date fair value)	2014				2013				2012
	Restricted ordinary shares granted	46				181				325

	Weighted average grant date fair value	$	31.86			$	29.44			$	20.92

	Aggregate grant date fair value	$	1,463			$	5,325			$	6,811

	Compensation expense related to restricted stock awards	$	5,239			$	4,419			$	5,399

	Estimated tax benefit related to restricted stock awards	$	1,233			$	1,047			$	1,113

	Non-vested restricted stock awards at December 31, 2014 and for the year then ended were as follows:


	(In thousands except for weighted average grant date fair value)	Number of			Weighted
		Shares			Average Grant
					Date Fair Value
	Unvested at December 31, 2013	593			$	33.92

	Granted	46			$	31.86

	Vested	(201	)		$	27.79

	Forfeited	(5	)		$	44.01

	Unvested at December 31, 2014	433			$	36.41

Summary of restricted stock units and restricted stock unit activity	Non-vested restricted stock units at December 31, 2014 and for the year then ended were as follows:


	(In thousands except for weighted average grant date fair value)	Number of			Weighted
		Shares			Average Grant
					Date Fair Value
	Unvested at December 31, 2013	2,931			$	25.77

	Granted	1,867			$	30.6

	Vested	(1,388	)		$	24.8

	Forfeited	(162	)		$	28.05

	Unvested at December 31, 2014	3,248			$	28.93

	A summary of the restricted stock units issued to officers of the Company and its subsidiaries for the indicated years ended December 31 is as follows:


	(In thousands)	2014				2013				2012
	Restricted stock units granted	1,867				1,803				1,312

	Aggregate grant date fair value	$	57,134			$	51,829			$	27,194

	Compensation expense related to restricted stock units	$	41,879			$	32,874			$	24,451

	Estimated tax benefit related to restricted stock units	$	11,607			$	8,813			$	6,501

Summary of performance units and performance units activity	A summary of the performance units issued to certain employees of the Company for the indicated years ended December 31 is as follows:


	(In thousands)	2014				2013				2012
	Performance units granted	572				656				1,527

	Potential maximum share payout	1,144				1,312				3,054

	Aggregate grant date fair value	$	16,345			$	17,753			$	29,537

	Compensation expense related to performance units	$	24,089			$	1,041			$	9,919

	Estimated tax benefit (charge) related to performance units	$	4,250			$	(176	)		$	1,943

	Non-vested restricted performance units as of December 31, 2014 were as follows:


	(In thousands except for weighted average grant date fair value)	Number of			Weighted
		Shares			Average Grant
					Date Fair Value
	Unvested at December 31, 2013	1,687			$	22.99

	Granted	572			$	28.57

	Vested	(340	)		$	22.06

	Forfeited	(100	)		$	25.98

	Performance driven addition (reduction)	721			$	26.46

	Unvested at December 31, 2014	2,540			$	25.24

Retirement_Plans_Tables

Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Funded status by geographical region	The funded status by geographical region of all the Company’s retirement plans at December 31, 2014 and 2013 is as follows:


	Funded Status	2014				2013
	(U.S. dollars in thousands)
	U.S.	$	(13,124	)		$	(6,181	)
	U.K.	(7,742		)		(7,654		)
	Other European	(22,977		)		(20,983		)
	Funded status – end of year	$	(43,843	)		$	(34,818	)
Change in projected benefit obligation

	Change in projected benefit obligation	2014				2013
	(U.S. dollars in thousands)
	Projected benefit obligation – beginning of year	$	81,976			$	83,083

	Service cost (1)	1,279				1,491

	Interest cost	3,747				3,599

	Actuarial (gain) / loss	13,402				(5,091		)

	Benefits and expenses paid	(2,761		)		(2,307		)
	Foreign currency (gains) / losses	(3,817		)		1,201

	Settlements	(702		)		—

	Projected benefit obligation – end of year	$	93,124			$	81,976

	(1) Service costs include cost of living adjustments on curtailed plans.
Change in plan assets

	Change in plan assets	2014				2013
	(U.S. dollars in thousands)
	Fair value of plan assets – beginning of year	$	47,158			$	39,313

	Actual return on plan assets	3,543				6,113

	Employer contributions	1,187				2,919

	Benefits and expenses paid	(1,932		)		(1,462		)
	Foreign currency gains / (losses)	(675		)		275

	Fair value of plan assets – end of year	$	49,281			$	47,158

	Funded status – end of year	$	(43,843	)		$	(34,818	)
	Accrued pension liability	$	43,843			$	34,818

Components of net benefit cost	The components of the net benefit cost for the years ended December 31, 2014, 2013 and 2012 are as follows:


	Components of net benefit cost	2014				2013				2012
	(U.S. dollars in thousands)
	Service cost	$	1,279			$	1,491			$	1,291

	Interest cost	3,747				3,589				3,557

	Expected return on plan assets	(2,859		)		(3,096		)		(3,028		)
	Amortization of net actuarial loss	812				1,440				915

	Transfer from AOCI	—				—				3,363

	Net benefit cost	$	2,979			$	3,424			$	6,098

Weighted average assumptions used	The table below includes disclosure of these rates on a weighted-average basis, for the years ended December 31 as indicated:


		2014									2013
		U.S. Plans			U.K. Plans			Other European Plans			U.S. Plans			U.K. Plans		Other European Plans
	Net Benefit Cost – Weighted-average assumptions
	Discount rate	4.95	%		4.6	%		3.5	%		4	%		4.5	%	4.2	%
	Expected long-term rate of return on plan assets	6.5	%		4.6	%		N/A			8	%		5.7	%	N/A

	Rate of compensation increase	N/A			5.5	%		2.5	%		N/A			4.9	%	2.5	%

	Benefit Obligation – Weighted-average assumptions
	Discount rate	3.91	%		4.6	%		2.4	%		4.95	%		4.5	%	3.5	%
	Rate of compensation increase	N/A			5.5	%		2.5	%		N/A			4.9	%	2.5	%

Allocation of plan assets - UK pension	The assets in the scheme and the expected rates of return were as follows:


	(U.S. dollars in thousands, except percentages)	Expected			Weighted				Expected			Weighted
		Return on			Value at				Return on			Value at
		Assets for			December 31,				Assets for			December 31,
		2014			2014				2013			2013
	Equities	7.4	%		$	7,787			6.8	%		$	7,048

	Gilts	3.6	%		1,579				3	%		1,775

	Corporate Bonds	4.6	%		1,594				4.5	%		1,758

	Other (cash)	4	%		224				3.4	%		133

	Total market fair value of assets				$	11,184						$	10,714

Estimated future benefit payments	The estimated future benefit payments with respect to the U.S. defined benefit pension plans are as follows:


	(U.S. dollars in thousands)	Retirement Plan				Benefits Equalization Plan				Total
	2015	$	876			$	425			$	1,301

	2016	$	925			$	425			$	1,350

	2017	$	1,001			$	421			$	1,422

	2018	$	1,064			$	424			$	1,488

	2019	$	1,255			$	522			$	1,777

	2020-2024	$	9,462			$	2,927			$	12,389

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2014
Comprehensive Income Loss Note [Abstract]
Components of acculumated other comprehensive income (loss)	The changes in AOCI, net of tax, by component for the indicated years ended December 31 are as follows:


	(U.S. dollars in thousands)	Unrealized Gains (Losses) on Investments (1)			OTTI Losses Recognized in AOCI				Foreign Currency Translation Adjustments			Underfunded Pension Liability			Cash Flow Hedge		Total
	Balance, net of tax, December 31, 2011	$	710,447		$	(188,651	)		$	77,555		$	(17,521	)	$	1,235	$	583,065

	OCI before reclassifications	985,544			—				(6,791		)	(8,126		)	—		970,627

	Amounts reclassified from AOCI	(81,678		)	67,580				350			4,273			439		(9,036		)

	Tax (benefit) expense	(23,103		)	(300		)		(1,715		)	482			—		(24,636		)

	Net current period OCI - net of tax	$	880,763		$	67,280			$	(8,156	)	$	(3,371	)	$	439	$	936,955

	Balance, net of tax, December 31, 2012	$	1,591,210		$	(121,371	)		$	69,399		$	(20,892	)	$	1,674	$	1,520,020

	OCI before reclassifications (1)	(742,768		)	—				(62,934		)	9,722			—		(795,980		)

	Amounts reclassified from AOCI	(119,970		)	32,193				206			1,440			439		(85,692		)

	Tax (benefit) expense	93,960			(12		)		7,870			(3,509		)	—		98,309

	Net current period OCI - net of tax	$	(768,778	)	$	32,181			$	(54,858	)	$	7,653		$	439	$	(783,363	)

	Balance, net of tax, December 31, 2013	$	822,432		$	(89,190	)		$	14,541		$	(13,239	)	$	2,113	$	736,657

	OCI before reclassifications (1)	954,326			—				(26,497		)	(10,877		)	—		916,952

	Amounts reclassified from AOCI	(143,330		)	14,082				87			812			255		(128,094		)

	Tax (benefit) expense	(43,314		)	(939		)		681			2,515			—		(41,057		)

	Net current period OCI - net of tax	$	767,682		$	13,143			$	(25,729	)	$	(7,550	)	$	255	$	747,801

	Balance, net of tax, December 31, 2014	$	1,590,114		$	(76,047	)		$	(11,188	)	$	(20,789	)	$	2,368	$	1,484,458

	____________

	-1	Included in these amounts is the impact of Shadow Adjustments. During the year ended December 31, 2013, the initial impact of $44.7 million was recorded. During the year ended December 31, 2014, additional net impacts of $400.5 million were recorded, resulting in a total cumulative net impact of Shadow Adjustments on future policy benefit reserves of $445.1 million at December 31, 2014.
Reclassifications out of AOCI	The reclassifications out of AOCI along with the associated income statement line items affected by component, and the total related tax (expense) benefit for indicated years ended December 31, are as follows:


	Gross Amount Reclassified From AOCI
	Details About AOCI Components	2014			2013			Affected Line Item in the Statement of Income
	(U.S. dollars in thousands)
	Unrealized gains and losses on investments:
		$	(175,639	)	$	(130,236	)	Net realized gains (losses) on investments sold
		54,095			$	10,266		OTTI on investments

		(21,786		)	$	—		Net realized and unrealized gains (losses) on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets

		$	(143,330	)	$	(119,970	)	Total before tax
		(1,593		)	$	5,183		Provision (benefit) for income tax

		$	(144,923	)	$	(114,787	)	Net of tax
	OTTI losses recognized in OCI:
		$	11,848		$	26,160		Net realized gains (losses) on investments sold

		2,234			$	6,033		OTTI on investments transferred to (from) OCI

		$	14,082		$	32,193		Total before tax

		(175		)	$	(12	)	Provision (benefit) for income tax
		$	13,907		$	32,181		Net of tax

	Foreign Currency Translation:
	Foreign exchange relating to affiliate investments	$	87		$	206		Exchange gains (losses) - before tax

		—			$	—		Provision (benefit) for income tax

		$	87		$	206		Net of tax


	Underfunded Pension Liability:
	Pension expense	$	812		$	1,440		Operating Expenses

		(206		)	$	—		Provision (benefit) for income tax

		$	606		$	1,440		Net of tax


	Gains and losses on cash flow hedges:
	Interest rate contracts	$	255		$	439		Interest Expense

		—			$	—		Provision (benefit) for income tax

		$	255		$	439		Net of tax


	Total reclassifications for the period, gross of tax	$	(128,094	)	(85,692		)
	Tax (benefit) expense	(1,974		)	5,171

	Total reclassifications for the period, net of tax	$	(130,068	)	(80,521		)

Dividends_Tables

Dividends (Tables)	12 Months Ended
Dividends (Tables)	Dec. 31, 2014
Dividends Disclosure [Abstract]
Schedule of dividends paid	XL-Cayman paid dividends to Series D and Series E preference shareholders for the indicated years ended December 31, as follows:


	(U.S. dollars in millions)	2014		2013		2012
	Series D preference ordinary shares (1) (2)	$	11.7	$	12.3	$	14
	Series D preference ordinary shares (1) (2)	$	11.7	$	12.3	$	14
	Series E preference ordinary shares (3)	$	65.1	$	65.1	$	65.1
	Series E preference ordinary shares (3)	$	65.1	$	65.1	$	65.1
	____________

	-1	On October 31, 2014, the Company announced that the Board of Directors of XL-Cayman resolved to pay a dividend of $8.5563 per share on XL-Cayman’s Series D Preference Ordinary Shares. The dividend was paid on January 15, 2015 to all shareholders of record at January 1, 2015.

	-2	On February 20, 2015, the Company announced that the Board of Directors of XL-Cayman, resolved on February 19, 2015 to pay a dividend of $8.4315 per share on XL-Cayman’s Series D Preference Ordinary Shares. The dividend will be paid on April 15, 2015 to all shareholders of record at April 1, 2015.

	-3	On February 20, 2015, the Company announced that the Board of Directors of XL-Cayman, resolved on February 19, 2015 to pay a dividend of $32.50 per share on XL-Cayman’s Series E Preference Ordinary Shares. The dividend will be paid on April 15, 2015 to all shareholders of record at April 1, 2015.

Taxation_Tables

Taxation (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Summary of income tax examinations	The following table details the years that are the subject of open examinations, by major tax jurisdiction. While the Company cannot estimate with certainty the outcome of these examinations, the Company does not believe that adjustments from open tax years will result in a significant change to the Company's results from operations.


	Jurisdiction	Tax Years
	U.S.	2013
	Ireland	2006 - 2009
	U.K.	2007 - 2010
	Germany	2006 - 2009
	Switzerland	2009 - 2010
	The following table details open tax years that are open to assessment by local tax authorities, in the following major tax jurisdictions.


	Jurisdiction	Tax Years
	U.S.	2011 - 2014
	Ireland	2006 - 2014
	U.K.	2007 - 2010,
		2012 - 2014
	Germany	2007 - 2014
	Switzerland	2009 - 2014
	France	2012 - 2014
Distribution of income (loss) before income tax, by jurisdiction	The Company’s income (loss) before income tax and non-controlling interests was distributed between U.S. and non-U.S. for the years ended December 31, 2014, 2013 and 2012 as follows:


	Income (loss) before income tax:	2014			2013			2012
	(U.S. dollars in thousands)
	U.S.	$	228,708		$	188,503		$	50,439

	Non U.S.	137,027			1,025,649			713,972

	Total	$	365,735		$	1,214,152		$	764,411

Components of income tax expense	The income tax provisions for the years ended December 31, 2014, 2013 and 2012 were as follows:


	(U.S. dollars in thousands)	2014			2013			2012
	Current expense:
	U.S.	$	45,598		$	49,566		$	11,966

	Non U.S.	81,371			41,921			45,614

	Total current expense	$	126,969		$	91,487		$	57,580

	Deferred expense (benefit):
	U.S.	$	8,572		$	700		$	(56,602	)

	Non U.S.	(38,644		)	(14,682		)	33,050

	Total deferred expense (benefit)	$	(30,072	)	$	(13,982	)	$	(23,552	)
	Total tax expense	$	96,897		$	77,505		$	34,028

Applicable statutory tax rates by jurisdiction	The applicable statutory tax rates of the most significant jurisdictions contributing to the overall taxation of the Company are:


	Jurisdiction	Applicable Statutory Taxation Rates
	Ireland (1)	12.5	%
	Ireland (1)	25	%
	Bermuda	—	%
	U.S.	35	%
	U.K.	21.5	%
	Switzerland (2)	7.83	%
	Switzerland (2)	21.2	%
	Germany	15	%
	France	38	%
	____________

	-1	The different applicable statutory taxation rates in Ireland relate to entities classified as trading or non-trading companies.

	-2	The different applicable statutory taxation rates in Switzerland relate to entities classified as trading or holding companies
Reconciliation of effective tax rate	A reconciliation of the difference between the provision for income taxes and the expected tax provision at the weighted average tax rate for the years ended December 31, 2014, 2013 and 2012 is provided below:


	(U.S. dollars in thousands)	2014			2013			2012
	Expected tax (benefit) provision at weighted average rate	$	132,775		$	43,092		$	53,358

	Permanent differences:
	Non-taxable (income) loss	(19,870		)	(50,745		)	(42,428		)
	Prior year adjustments	5,990			6,067			(622		)

	Prior year adjustments on completion of IRS examinations	—			—			(19,192		)

	State, local and foreign taxes	47,078			12,225			18,312

	Valuation allowance	(181		)	5,754			(16,644		)

	Net allocated investment income	3,399			5,949			41,727

	Stock options	411			1,501			4,749

	Non-deductible expenses	22,556			23,662			16,145

	Net realized capital loss carry-forward valuation allowance reduction	(2,916		)	—			(24,473		)

	Adjustments related to Life Retro Arrangements	(99,535		)	—			—

	Non-taxable reserve release	—			—			3,096

	Uncertain tax positions	7,190			30,000			—

	Total tax expense	$	96,897		$	77,505		$	34,028

Components of net deferred tax assets	Significant components of the Company’s deferred tax assets and liabilities at December 31, 2014 and 2013 were as follows:


	(U.S. dollars in thousands)	2014			2013
	Deferred tax asset:
	Net unpaid loss reserve discount	$	90,262		$	105,511

	Net unearned premiums	72,752			69,811

	Compensation liabilities	77,578			62,710

	Net operating losses	49,834			89,233

	Investment adjustments	13,022			12,573

	Pension	8,114			5,695

	Bad debt reserve	6,626			7,337

	Amortizable goodwill	6,694			7,976

	Net unrealized depreciation on investments	1,484			9,984

	Stock options	11,985			12,171

	Depreciation	7,599			3,501

	Net realized capital losses	97,189			140,993

	Deferred intercompany capital losses	57,427			69,500

	Untaxed Lloyd's result	7,254			2,533

	Deferred acquisition costs	11,386			—

	Other	2,282			9,638

	Deferred tax asset, gross of valuation allowance	$	521,488		$	609,166

	Valuation allowance	207,062			261,924

	Deferred tax asset, net of valuation allowance	$	314,426		$	347,242

	Deferred tax liability:
	Net unrealized appreciation on investments	$	63,642		$	28,843

	Unremitted earnings	$	5,125		$	6,717

	Deferred acquisition costs	2,737			7,057

	Currency translation adjustments	3,969			7,195

	Regulatory reserves	65,965			131,750

	Investment adjustment	12,061			6,112

	Untaxed Lloyd’s result	11,422			—

	Other	11,260			8,014

	Deferred tax liability	$	176,181		$	195,688

	Net Deferred Tax Asset	$	138,245		$	151,554

Summary of valuation allowance	At December 31, 2014 and 2013, the valuation allowance of $207.1 million and $261.9 million, respectively, related primarily to net operating loss carry forwards and realized capital loss carry forwards in the following jurisdictions:


	Jurisdiction	2014			2013
	(U.S. dollars in thousands)
	Switzerland	$	1,459		$	11,457

	Ireland	72,363			60,133

	U.S.	123,695			175,372

	Other	9,545			14,962

	Valuation Allowance Total	$	207,062		$	261,924

Reconciliation of unrecognized tax benefits	The following table presents a reconciliation of the Company’s unrecognized tax benefits:


	(U.S. dollars in thousands)	2014			2013
	Unrecognized tax benefits, beginning of the year	$	30,000		$	—

	Increases for tax positions taken during the year	12,182			9,591

	Increases for tax positions taken in prior years	15,304			20,409

	Decreases for tax positions taken during the year	—			—

	Decreases for tax positions taken in prior years	(20,296		)	—

	Decreases for settlement with taxing authorities	—			—

	Decreases for lapse of the applicable statute of limitations	—			—

	Unrecognized tax benefits, end of year	$	37,190		$	30,000

Statutory_Financial_Data_Table

Statutory Financial Data (Tables)	12 Months Ended
Statutory Financial Data (Tables)	Dec. 31, 2014
Statutory Capital And Surplus Disclosure Text Block [Abstract]
Schedule of statutory capital	Statutory capital and surplus for the principal operating subsidiaries of the Company for the years ended December 31, 2014 and 2013 are summarized below:


	(U.S. dollars in thousands)	Bermuda (1)				U.S. (2)				U.K., Europe and Other
	(U.S. dollars in thousands)	2014		2013		2014		2013		2014		2013
	Required statutory capital and surplus	$	6,194,832	$	6,583,273	$	668,794	$	657,865	$	1,604,721	$	1,970,909
	Required statutory capital and surplus	$	6,194,832	$	6,583,273	$	668,794	$	657,865	$	1,604,721	$	1,970,909
	Actual statutory capital and surplus (3)	$	10,309,895	$	10,168,744	$	2,233,596	$	2,244,505	$	2,712,552	$	2,684,317
	Actual statutory capital and surplus (3)	$	10,309,895	$	10,168,744	$	2,233,596	$	2,244,505	$	2,712,552	$	2,684,317
	____________

	-1	Required statutory capital and surplus at December 31, 2014 represents 100% Bermuda Solvency Capital Requirement (“BSCR”) level for the top Bermuda operating subsidiary, XL Insurance (Bermuda) Ltd, calculated on a consolidated basis (and therefore includes a BSCR requirement for all regions).

	-2	Required statutory capital and surplus represents 100% Risk-Based Capital level for principal U.S. operating subsidiaries.

	-3	Statutory assets in Bermuda include investments in other U.S. and international subsidiaries reported separately herein.
Schedule of statutory net income loss	Statutory net income (loss) for the principal operating subsidiaries of the Company for the years ended December 31, 2014, 2013 and 2012 is summarized below:


	(U.S. dollars in thousands)	2014		2013		2012
	Bermuda	$	361,033	$	1,241,878	$	857,832
	Bermuda	$	361,033	$	1,241,878	$	857,832
	U.S.	$	155,751	$	124,310	$	106,510
	U.S.	$	155,751	$	124,310	$	106,510
	U.K., Europe and Other	$	215,787	$	1,465	$	144,829
	U.K., Europe and Other	$	215,787	$	1,465	$	144,829

Computation_of_Earnings_Per_Or1

Computation of Earnings Per Ordinary Share and Ordinary Share Equivalent (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Computation of basic and diluted earnings per share	The following table sets forth the computation of basic and diluted earnings per ordinary share for the years ended December 31, 2014, 2013 and 2012:


	(U.S. dollars in thousands, except per share amounts)	2014		2013		2012
	Basic earnings per ordinary share and ordinary share equivalents outstanding:
	Net income (loss) attributable to ordinary shareholders	$	188,340	$	1,059,916	$	651,128

	Weighted average ordinary shares outstanding	267,103		287,801		307,372

	Basic earnings per ordinary share and ordinary share equivalents outstanding	$	0.71	$	3.68	$	2.12


	Diluted earnings per ordinary share and ordinary share equivalents outstanding:
	Weighted average ordinary shares outstanding – basic	267,103		287,801		307,372

	Impact of share based compensation and certain conversion features	4,424		4,268		2,910

	Weighted average ordinary shares outstanding – diluted	271,527		292,069		310,282

	Diluted earnings per ordinary share & ordinary share equivalents outstanding	$	0.69	$	3.63	$	2.1

	Dividends per ordinary share	$	0.64	$	0.56	$	0.44

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Summary of related party transactions

	(U.S. dollars in thousands)	2014		2013		2012
	Reported net premiums written	$	91,261	$	73,085	$	61,146

	Net losses incurred	$	38,927	$	29,042	$	37,664

	Reported acquisition costs	$	35,711	$	25,275	$	24,014

Unaudited_Quarterly_Financial_1

Unaudited Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Quarterly financial data	The following is a summary of the unaudited quarterly financial data for 2014 and 2013:


	(U.S. dollars in thousands, except per share amounts)	First		Second			Third		Fourth
		Quarter		Quarter			Quarter		Quarter
	2014
	Net premiums earned – P&C operations	$	1,412,528	$	1,438,076		$	1,453,673	$	1,413,161

	Net premiums earned – Corporate and Other	$	76,311	$	58,518		$	19,739	$	23,064

	Underwriting profit (loss) – P&C operations	$	144,874	$	167,946		$	144,375	$	218,851

	Net income (loss) attributable to ordinary shareholders	$	255,717	$	(279,261	)	$	72,384	$	139,500

	Net income (loss) per ordinary share and ordinary equivalent – basic	$	0.93	$	(1.03	)	$	0.27	$	0.54

	Net income (loss) per ordinary share and ordinary equivalent – diluted	$	0.91	$	(1.03	)	$	0.27	$	0.53

	2013
	Net premiums earned – P&C operations	$	1,464,246	$	1,488,497		$	1,550,629	$	1,510,727

	Net premiums earned – Corporate and Other	$	65,445	$	73,896		$	74,683	$	81,398

	Underwriting profit (loss) – P&C operations	$	180,588	$	92,124		$	76,900	$	101,450

	Net income (loss) attributable to ordinary shareholders	$	350,790	$	272,698		$	135,648	$	300,780

	Net income (loss) per ordinary share and ordinary equivalent – basic	$	1.19	$	0.94		$	0.48	$	1.07

	Net income (loss) per ordinary share and ordinary equivalent – diluted	$	1.17	$	0.93		$	0.47	$	1.05

General_Details

General (Details)	Dec. 31, 2014
General (Details)	country
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of Countries in which Entity Operates	25

Significant_Accounting_Policie2

Significant Accounting Policies (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Significant Accounting Policies [Line Items]
Premiums Earned and Associated Tax Accruals Adjustment Amount	$20
Options, life of award	10 years
Alternative funds
Significant Accounting Policies [Line Items]
Alternative investments, timelag for reporting	1 month
Private investment funds
Significant Accounting Policies [Line Items]
Alternative investments, timelag for reporting	3 months
Operating affiliates
Significant Accounting Policies [Line Items]
Alternative investments, timelag for reporting	3 months
Investments in the common stock of a corporation
Significant Accounting Policies [Line Items]
Threshold for signicant influence, percentage	20.00%
Investments in closed end funds, limited partnerships, LLCs or similar investment vehicles
Significant Accounting Policies [Line Items]
Threshold for signicant influence, percentage	3.00%
Maximum
Significant Accounting Policies [Line Items]
Hedge effectiveness, percentage	125.00%
Vesting period required	4 years
Minimum
Significant Accounting Policies [Line Items]
Hedge effectiveness, percentage	80.00%
Vesting period required	3 years

Sale_of_Life_Reinsurance_Subsi2

Sale of Life Reinsurance Subsidiary - Impact of Life Retro Arrangements (Details) (USD $)	12 Months Ended			7 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Underwriting profit (loss)	$585,907	$245,191	$3,968
Net investment income - Life Funds Withheld Assets	918,625	957,716	1,012,348
Exchange (gains) losses	37,568	28,243	-10,545
Other income and expenses	-6,891	-5,692	3,768
Net realized and unrealized (gains) losses on derivative instruments	29,886	7,798	5,221
Net income (loss)	268,838	1,136,647	730,383
Change in adjustments related to future policy benefit reserves, net of tax	-400,456	-44,660	0
Change in cumulative translation adjustment - Life Funds Withheld Assets, net of tax	-25,729	-54,858	-8,156
Comprehensive income (loss)	747,801	-783,363	936,955
Life Funds Withheld Assets [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net investment income - Life Funds Withheld Assets	129,575	0	0
Net realized gains (losses) on investments sold	5,067	0	0
OTTI on investments - Life Funds Withheld Assets	20,587	0	0
Net realized and unrealized (gains) losses on derivative instruments	-488,222	0	0
Change in net unrealized gains (losses) on investments, net of tax	274,083	0	0
Life Funds Withheld Assets [Member] \| XL Re Life (SAC) Ltd [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Underwriting profit (loss)				11,649	[1]
Net investment income - Life Funds Withheld Assets				129,575
Net realized gains (losses) on investments sold				5,067
Net unrealized gains (losses) on investments - Trading				-9
OTTI on investments - Life Funds Withheld Assets				20,587
Exchange (gains) losses				10,099
Other income and expenses				-1,610
Net realized and unrealized (gains) losses on derivative instruments				-488,222
Net income (loss)				-354,038
Change in net unrealized gains (losses) on investments, net of tax				274,083
Change in adjustments related to future policy benefit reserves, net of tax				74,009
Change in cumulative translation adjustment - Life Funds Withheld Assets, net of tax				17,595
Total changes to other comprehensive income as a result of Life Retro Arrangements				365,687
Comprehensive income (loss)				$11,649	[1]

[1]	The underwriting profit of $11.6 million relates to a premium adjustment relating to the Life Retro Arrangements transaction which was completed on May 30, 2014. Excluding this transaction, the impact to comprehensive income relating to the Life Retro Arrangements was nil for the year ended December 31, 2014.

Sale_of_Life_Reinsurance_Subsi3

Sale of Life Reinsurance Subsidiary - Narrative (Details) (USD $)	12 Months Ended			0 Months Ended	7 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	1-May-14	Dec. 31, 2014		30-May-14
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Underwriting profit (loss)	$585,907,000	$245,191,000	$3,968,000
Liability for Future Policy Benefits	4,707,199,000	4,803,816,000			4,707,199,000
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable: 2014, $4,265,678; 2013, nil)	1,155,016,000	0			1,155,016,000
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 Reserve Retention	400,000,000				400,000,000
Estimated Future Policy Benefit Reserve Retention							400,000,000
Future Policy Benefit Reserves Recoverable	4,265,678,000				4,265,678,000		4,800,000,000
Pro Forma Effect of Sale, After Tax Net Loss				621,300,000
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable: 2014, $4,265,678; 2013, nil)	1,155,016,000				1,155,016,000
Assets held on a funds withheld basis relating to the Life Retro Arrangements	5,420,694,000				5,420,694,000
Life Insurance Product Line [Member] \| XL Re Life (SAC) Ltd [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liability for Future Policy Benefits	4,707,199,000				4,707,199,000		5,200,000,000
Life Funds Withheld Assets [Member] \| XL Re Life (SAC) Ltd [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Underwriting profit (loss)					11,649,000	[1]
Total changes to other comprehensive income as a result of Life Retro Arrangements					$365,687,000

[1]	The underwriting profit of $11.6 million relates to a premium adjustment relating to the Life Retro Arrangements transaction which was completed on May 30, 2014. Excluding this transaction, the impact to comprehensive income relating to the Life Retro Arrangements was nil for the year ended December 31, 2014.

Fair_Value_Measurements_Schedu

Fair Value Measurements - Schedule of assets and liabilities that were accounted for at fair value (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
ASSETS
Fixed maturities, AFS, at fair value	$29,359,034		$27,500,136
Equity securities, AFS, at fair value	868,292		1,040,237
Short-term investments, AFS, at fair value			456,288
Total investments available for sale	30,484,053		28,996,661
Fixed maturities, trading, at fair value	1,171		0
Collateral and counterparty netting, asset	-696		-1,342
Liabilities:
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable: 2014, $4,265,678; 2013, nil)	1,155,016		0
Collateral and counterparty netting, liability	-696		-1,342
U.S. Government and Government - Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value			2,501,851
Corporate
ASSETS
Fixed maturities, AFS, at fair value			11,125,830
Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value			3,546,122
Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value			398,768
Commercial mortgage-backed securities ('CMBS') [Member]
ASSETS
Fixed maturities, AFS, at fair value			1,246,795
Collateralized debt obligations ('CDO') [Member]
ASSETS
Fixed maturities, AFS, at fair value			717,313
Other asset-backed securities
ASSETS
Fixed maturities, AFS, at fair value			1,242,104
U.S. States and political subdivisions of the States [Member]
ASSETS
Fixed maturities, AFS, at fair value			1,845,812
Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value			4,875,541
Recurring
ASSETS
Fixed maturities, AFS, at fair value			27,500,136
Equity securities, AFS, at fair value			1,040,237
Short-term investments, AFS, at fair value			456,288	[1],[2]
Total investments available for sale	30,484,053		28,996,661
Cash equivalents	1,501,832	[3]	1,061,150	[3]
Other investments	894,057	[4]	870,582	[4]
Other assets	135,963	[5]	26,145	[5]
Total assets accounted for at fair value	33,150,274		30,954,538
Liabilities:
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable: 2014, $4,265,678; 2013, nil)	450,831	[6]
Financial instruments sold, but not yet purchased	30,406	[7]	28,861	[7]
Other liabilities	30,488	[5]	104,143	[5]
Total liabilities accounted for at fair value	511,725		133,004
Recurring \| U.S. Government and Government - Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value			2,501,851
Recurring \| Corporate
ASSETS
Fixed maturities, AFS, at fair value			11,125,830	[1]
Recurring \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value			3,546,122
Recurring \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value			398,768
Recurring \| Commercial mortgage-backed securities ('CMBS') [Member]
ASSETS
Fixed maturities, AFS, at fair value			1,246,795
Recurring \| Collateralized debt obligations ('CDO') [Member]
ASSETS
Fixed maturities, AFS, at fair value			717,313
Recurring \| Other asset-backed securities
ASSETS
Fixed maturities, AFS, at fair value			1,242,104	[1]
Recurring \| U.S. States and political subdivisions of the States [Member]
ASSETS
Fixed maturities, AFS, at fair value			1,845,812
Recurring \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value			4,875,541
Recurring \| Quoted prices in active markets for identical assets (Level 1)
ASSETS
Fixed maturities, AFS, at fair value			0
Equity securities, AFS, at fair value			540,331
Short-term investments, AFS, at fair value			0	[1],[2]
Total investments available for sale	502,284		540,331
Cash equivalents	1,103,877	[3]	834,514	[3]
Other investments	0	[4]	0	[4]
Other assets	0	[5]	0	[5]
Total assets accounted for at fair value	1,606,621		1,374,845
Liabilities:
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable: 2014, $4,265,678; 2013, nil)	0	[6]
Financial instruments sold, but not yet purchased	4,737	[7]	0	[7]
Other liabilities	0	[5]	0	[5]
Total liabilities accounted for at fair value	4,737		0
Recurring \| Quoted prices in active markets for identical assets (Level 1) \| U.S. Government and Government - Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value			0
Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Corporate
ASSETS
Fixed maturities, AFS, at fair value			0	[1]
Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value			0
Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value			0
Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Commercial mortgage-backed securities ('CMBS') [Member]
ASSETS
Fixed maturities, AFS, at fair value			0
Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Collateralized debt obligations ('CDO') [Member]
ASSETS
Fixed maturities, AFS, at fair value			0
Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Other asset-backed securities
ASSETS
Fixed maturities, AFS, at fair value			0	[1]
Recurring \| Quoted prices in active markets for identical assets (Level 1) \| U.S. States and political subdivisions of the States [Member]
ASSETS
Fixed maturities, AFS, at fair value			0
Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value			0
Recurring \| Significant other observable inputs (Level 2)
ASSETS
Fixed maturities, AFS, at fair value			26,723,418
Equity securities, AFS, at fair value			499,906
Short-term investments, AFS, at fair value			454,273	[1],[2]
Total investments available for sale	29,280,719		27,677,597
Cash equivalents	397,955	[3]	226,636	[3]
Other investments	708,974	[4]	757,110	[4]
Other assets	122,996	[5]	27,487	[5]
Total assets accounted for at fair value	30,644,553		28,688,830
Liabilities:
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable: 2014, $4,265,678; 2013, nil)	450,831	[6]
Financial instruments sold, but not yet purchased	25,669	[7]	28,861	[7]
Other liabilities	7,757	[5]	76,375	[5]
Total liabilities accounted for at fair value	484,257		105,236
Recurring \| Significant other observable inputs (Level 2) \| U.S. Government and Government - Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value			2,501,851
Recurring \| Significant other observable inputs (Level 2) \| Corporate
ASSETS
Fixed maturities, AFS, at fair value			11,094,257	[1]
Recurring \| Significant other observable inputs (Level 2) \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value			3,535,649
Recurring \| Significant other observable inputs (Level 2) \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value			398,759
Recurring \| Significant other observable inputs (Level 2) \| Commercial mortgage-backed securities ('CMBS') [Member]
ASSETS
Fixed maturities, AFS, at fair value			1,234,262
Recurring \| Significant other observable inputs (Level 2) \| Collateralized debt obligations ('CDO') [Member]
ASSETS
Fixed maturities, AFS, at fair value			7,060
Recurring \| Significant other observable inputs (Level 2) \| Other asset-backed securities
ASSETS
Fixed maturities, AFS, at fair value			1,230,227	[1]
Recurring \| Significant other observable inputs (Level 2) \| U.S. States and political subdivisions of the States [Member]
ASSETS
Fixed maturities, AFS, at fair value			1,845,812
Recurring \| Significant other observable inputs (Level 2) \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value			4,875,541
Recurring \| Significant other unobservable inputs (Level 3)
ASSETS
Fixed maturities, AFS, at fair value			776,718
Equity securities, AFS, at fair value			0
Short-term investments, AFS, at fair value			2,015	[1],[2]
Total investments available for sale	701,050		778,733
Cash equivalents	0	[3]	0	[3]
Other investments	185,083	[4]	113,472	[4]
Other assets	13,663	[5]	0	[5]
Total assets accounted for at fair value	899,796		892,205
Liabilities:
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable: 2014, $4,265,678; 2013, nil)	0	[6]
Financial instruments sold, but not yet purchased	0	[7]	0	[7]
Other liabilities	23,427	[5]	29,110	[5]
Total liabilities accounted for at fair value	23,427		29,110
Recurring \| Significant other unobservable inputs (Level 3) \| U.S. Government and Government - Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value			0
Recurring \| Significant other unobservable inputs (Level 3) \| Corporate
ASSETS
Fixed maturities, AFS, at fair value			31,573	[1]
Recurring \| Significant other unobservable inputs (Level 3) \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value			10,473
Recurring \| Significant other unobservable inputs (Level 3) \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value			9
Recurring \| Significant other unobservable inputs (Level 3) \| Commercial mortgage-backed securities ('CMBS') [Member]
ASSETS
Fixed maturities, AFS, at fair value			12,533
Recurring \| Significant other unobservable inputs (Level 3) \| Collateralized debt obligations ('CDO') [Member]
ASSETS
Fixed maturities, AFS, at fair value			710,253
Recurring \| Significant other unobservable inputs (Level 3) \| Other asset-backed securities
ASSETS
Fixed maturities, AFS, at fair value			11,877	[1]
Recurring \| Significant other unobservable inputs (Level 3) \| U.S. States and political subdivisions of the States [Member]
ASSETS
Fixed maturities, AFS, at fair value			0
Recurring \| Significant other unobservable inputs (Level 3) \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value			0
Exclude Life Funds Withheld Assets [Member]
ASSETS
Fixed maturities, AFS, at fair value	24,177,469		27,500,136
Equity securities, AFS, at fair value	868,292
Short-term investments, AFS, at fair value	256,727
Total investments available for sale	25,302,488
Exclude Life Funds Withheld Assets [Member] \| U.S. Government and Government - Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	2,171,953
Exclude Life Funds Withheld Assets [Member] \| Corporate
ASSETS
Fixed maturities, AFS, at fair value	8,778,373
Exclude Life Funds Withheld Assets [Member] \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	3,728,576
Exclude Life Funds Withheld Assets [Member] \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	427,351
Exclude Life Funds Withheld Assets [Member] \| Commercial mortgage-backed securities ('CMBS') [Member]
ASSETS
Fixed maturities, AFS, at fair value	1,052,544
Exclude Life Funds Withheld Assets [Member] \| Collateralized debt obligations ('CDO') [Member]
ASSETS
Fixed maturities, AFS, at fair value	692,034
Exclude Life Funds Withheld Assets [Member] \| Other asset-backed securities
ASSETS
Fixed maturities, AFS, at fair value	1,065,293
Exclude Life Funds Withheld Assets [Member] \| U.S. States and political subdivisions of the States [Member]
ASSETS
Fixed maturities, AFS, at fair value	2,021,272
Exclude Life Funds Withheld Assets [Member] \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	4,240,073
Exclude Life Funds Withheld Assets [Member] \| Recurring
ASSETS
Fixed maturities, AFS, at fair value	24,177,469
Equity securities, AFS, at fair value	868,292
Short-term investments, AFS, at fair value	256,727	[1],[2]
Total investments available for sale	25,302,488
Exclude Life Funds Withheld Assets [Member] \| Recurring \| U.S. Government and Government - Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	2,171,953
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Corporate
ASSETS
Fixed maturities, AFS, at fair value	8,778,373	[1]
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	3,728,576
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	427,351
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Commercial mortgage-backed securities ('CMBS') [Member]
ASSETS
Fixed maturities, AFS, at fair value	1,052,544
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Collateralized debt obligations ('CDO') [Member]
ASSETS
Fixed maturities, AFS, at fair value	692,034
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Other asset-backed securities
ASSETS
Fixed maturities, AFS, at fair value	1,065,293	[1]
Exclude Life Funds Withheld Assets [Member] \| Recurring \| U.S. States and political subdivisions of the States [Member]
ASSETS
Fixed maturities, AFS, at fair value	2,021,272
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	4,240,073
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1)
ASSETS
Fixed maturities, AFS, at fair value	0
Equity securities, AFS, at fair value	502,284
Short-term investments, AFS, at fair value	0	[1],[2]
Total investments available for sale	502,284
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| U.S. Government and Government - Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Corporate
ASSETS
Fixed maturities, AFS, at fair value	0	[1]
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Commercial mortgage-backed securities ('CMBS') [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Collateralized debt obligations ('CDO') [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Other asset-backed securities
ASSETS
Fixed maturities, AFS, at fair value	0	[1]
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| U.S. States and political subdivisions of the States [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2)
ASSETS
Fixed maturities, AFS, at fair value	23,476,419
Equity securities, AFS, at fair value	366,008
Short-term investments, AFS, at fair value	256,727	[1],[2]
Total investments available for sale	24,099,154
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| U.S. Government and Government - Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	2,171,953
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| Corporate
ASSETS
Fixed maturities, AFS, at fair value	8,772,479	[1]
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	3,726,666
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	427,351
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| Commercial mortgage-backed securities ('CMBS') [Member]
ASSETS
Fixed maturities, AFS, at fair value	1,052,544
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| Collateralized debt obligations ('CDO') [Member]
ASSETS
Fixed maturities, AFS, at fair value	4,076
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| Other asset-backed securities
ASSETS
Fixed maturities, AFS, at fair value	1,060,005	[1]
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| U.S. States and political subdivisions of the States [Member]
ASSETS
Fixed maturities, AFS, at fair value	2,021,272
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	4,240,073
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3)
ASSETS
Fixed maturities, AFS, at fair value	701,050
Equity securities, AFS, at fair value	0
Short-term investments, AFS, at fair value	0	[1],[2]
Total investments available for sale	701,050
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| U.S. Government and Government - Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| Corporate
ASSETS
Fixed maturities, AFS, at fair value	5,894	[1]
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	1,910
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| Commercial mortgage-backed securities ('CMBS') [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| Collateralized debt obligations ('CDO') [Member]
ASSETS
Fixed maturities, AFS, at fair value	687,958
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| Other asset-backed securities
ASSETS
Fixed maturities, AFS, at fair value	5,288	[1]
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| U.S. States and political subdivisions of the States [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Exclude Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Life Funds Withheld Assets [Member]
ASSETS
Fixed maturities, AFS, at fair value	5,181,565		0
Fixed maturities, trading, at fair value	1,171
Life Funds Withheld Assets [Member] \| U.S. Government and Government - Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	18,724
Life Funds Withheld Assets [Member] \| Corporate
ASSETS
Fixed maturities, AFS, at fair value	2,817,980
Fixed maturities, trading, at fair value	1,171
Life Funds Withheld Assets [Member] \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	3,782
Life Funds Withheld Assets [Member] \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	85,335
Life Funds Withheld Assets [Member] \| Commercial mortgage-backed securities ('CMBS') [Member]
ASSETS
Fixed maturities, AFS, at fair value	193,167
Life Funds Withheld Assets [Member] \| Collateralized debt obligations ('CDO') [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Life Funds Withheld Assets [Member] \| Other asset-backed securities
ASSETS
Fixed maturities, AFS, at fair value	273,541
Life Funds Withheld Assets [Member] \| U.S. States and political subdivisions of the States [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Life Funds Withheld Assets [Member] \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	1,789,036
Life Funds Withheld Assets [Member] \| Recurring
ASSETS
Fixed maturities, AFS, at fair value	5,181,565
Fixed maturities, trading, at fair value	1,171
Cash equivalents	133,198
Life Funds Withheld Assets [Member] \| Recurring \| U.S. Government and Government - Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	18,724
Life Funds Withheld Assets [Member] \| Recurring \| Corporate
ASSETS
Fixed maturities, AFS, at fair value	2,817,980	[1]
Fixed maturities, trading, at fair value	1,171
Life Funds Withheld Assets [Member] \| Recurring \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	3,782
Life Funds Withheld Assets [Member] \| Recurring \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	85,335
Life Funds Withheld Assets [Member] \| Recurring \| Commercial mortgage-backed securities ('CMBS') [Member]
ASSETS
Fixed maturities, AFS, at fair value	193,167
Life Funds Withheld Assets [Member] \| Recurring \| Other asset-backed securities
ASSETS
Fixed maturities, AFS, at fair value	273,541
Life Funds Withheld Assets [Member] \| Recurring \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	1,789,036
Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1)
ASSETS
Fixed maturities, AFS, at fair value	0
Fixed maturities, trading, at fair value	0
Cash equivalents	460
Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| U.S. Government and Government - Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Corporate
ASSETS
Fixed maturities, AFS, at fair value	0	[1]
Fixed maturities, trading, at fair value	0
Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Commercial mortgage-backed securities ('CMBS') [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Other asset-backed securities
ASSETS
Fixed maturities, AFS, at fair value	0
Life Funds Withheld Assets [Member] \| Recurring \| Quoted prices in active markets for identical assets (Level 1) \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2)
ASSETS
Fixed maturities, AFS, at fair value	5,181,565
Fixed maturities, trading, at fair value	1,171
Cash equivalents	132,738
Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| U.S. Government and Government - Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	18,724
Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| Corporate
ASSETS
Fixed maturities, AFS, at fair value	2,817,980	[1]
Fixed maturities, trading, at fair value	1,171
Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	3,782
Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	85,335
Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| Commercial mortgage-backed securities ('CMBS') [Member]
ASSETS
Fixed maturities, AFS, at fair value	193,167
Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| Other asset-backed securities
ASSETS
Fixed maturities, AFS, at fair value	273,541
Life Funds Withheld Assets [Member] \| Recurring \| Significant other observable inputs (Level 2) \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	1,789,036
Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3)
ASSETS
Fixed maturities, AFS, at fair value	0
Fixed maturities, trading, at fair value	0
Cash equivalents	0
Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| U.S. Government and Government - Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| Corporate
ASSETS
Fixed maturities, AFS, at fair value	0	[1]
Fixed maturities, trading, at fair value	0
Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| Commercial mortgage-backed securities ('CMBS') [Member]
ASSETS
Fixed maturities, AFS, at fair value	0
Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| Other asset-backed securities
ASSETS
Fixed maturities, AFS, at fair value	0
Life Funds Withheld Assets [Member] \| Recurring \| Significant other unobservable inputs (Level 3) \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
ASSETS
Fixed maturities, AFS, at fair value	$0

[1]	Included are certain medium term notes supported primarily by pools of European investment grade credit with varying degrees of leverage. The notes had a fair value of $79.9 million and $154.6 million and an amortized cost of $68.4 million and $147.7 million at DecemberB 31, 2014 and DecemberB 31, 2013, respectively. These notes allow the investor to participate in cash flows of the underlying bonds including certain residual values, which could serve to either decrease or increase the ultimate values of these notes.
[2]	Short-term investments consist primarily of Corporate securities and U.S. and Non-U.S. Government and Government-Related/ Supported securities.
[3]	Cash equivalents balances subject to fair value measurement include certificates of deposit and money market funds. Operating cash balances are not subject to recurring fair value measurement guidance.
[4]	The Other investments balance excludes certain structured transactions including certain investments in project finance transactions, a payment obligation and liquidity financing provided to a structured credit vehicle as a part of a third party medium term note facility. These investments, which totaled $354.4 million at DecemberB 31, 2014 and $294.0 million at DecemberB 31, 2013, are carried at amortized cost. For further information, see Note 8, bOther Investments.b
[5]	Other assets and other liabilities include derivative instruments. The derivative balances included in each category are reported on a gross basis by level with a netting adjustment presented separately in the Collateral and Counterparty Netting column. The fair values of the individual derivative contracts are reported gross in their respective levels based on the fair value hierarchy. For further details regarding derivative fair values and associated collateral received or paid see Note 16, bDerivative Instruments
[6]	Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable) include balances related to the life retrocession embedded derivative, under which all investment results associated with the Life Funds Withheld Assets related the Life Retro Arrangements described in Note 3, "Sale of Life Reinsurance Subsidiary", accrue to the benefit of GCLR.
[7]	Financial instruments sold, but not yet purchased, represent bshort salesb and are included within bPayable for investments purchasedb on the balance sheets.

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional information about assets and liabilities measured at fair value on a recurring basis (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Corporate
Level 3 assets
Balance, beginning of period	$31,573	$30,098
Realized gains (losses)	199	4
Movement in unrealized gains (losses)	-128	766
Purchases and issuances	3,759	10,691
Sales	0	-71
Settlements	-6,543	-7,274
Transfers into Level 3	766	0
Transfers out of Level 3	-23,732	-2,641
Fixed maturities to short term investments classification change	0	0
Balance, end of period	5,894	31,573
Movement in total gains (losses) above relating to instruments still held at the reporting date	60	845
RMBS - Agency
Level 3 assets
Balance, beginning of period	10,473	32,005
Realized gains (losses)	5	10
Movement in unrealized gains (losses)	-18	-23
Purchases and issuances	120	0
Sales	0	-535
Settlements	-3,205	-3,349
Transfers into Level 3	0	0
Transfers out of Level 3	-5,465	-17,635
Fixed maturities to short term investments classification change	0	0
Balance, end of period	1,910	10,473
Movement in total gains (losses) above relating to instruments still held at the reporting date	-12	-27
RMBS - Non-Agency
Level 3 assets
Balance, beginning of period	9	116
Realized gains (losses)	1	-1
Movement in unrealized gains (losses)	1	-1
Purchases and issuances	0	3,326
Sales	0	0
Settlements	-11	-105
Transfers into Level 3	0	0
Transfers out of Level 3	0	-3,326
Fixed maturities to short term investments classification change	0	0
Balance, end of period	0	9
Movement in total gains (losses) above relating to instruments still held at the reporting date	0	-1
CMBS
Level 3 assets
Balance, beginning of period	12,533	25,347
Realized gains (losses)	3	3
Movement in unrealized gains (losses)	-3	-68
Purchases and issuances	1,376	0
Sales	0	0
Settlements	-12,533	-12,749
Transfers into Level 3	0	0
Transfers out of Level 3	-1,376	0
Fixed maturities to short term investments classification change	0	0
Balance, end of period	0	12,533
Movement in total gains (losses) above relating to instruments still held at the reporting date	0	-65
Collateralized debt obligations ('CDO') [Member]
Level 3 assets
Balance, beginning of period	710,253	701,736
Realized gains (losses)	3,781	4,364
Movement in unrealized gains (losses)	11,604	37,916
Purchases and issuances	185,710	136,035
Sales	-48,313	-48,226
Settlements	-175,077	-121,572
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fixed maturities to short term investments classification change	0	0
Balance, end of period	687,958	710,253
Movement in total gains (losses) above relating to instruments still held at the reporting date	14,432	39,259
Other asset-backed securities
Level 3 assets
Balance, beginning of period	11,877	18,128
Realized gains (losses)	-7	848
Movement in unrealized gains (losses)	65	1,691
Purchases and issuances	5,182	21,686
Sales	0	-15,711
Settlements	-5,705	-8,259
Transfers into Level 3	0	0
Transfers out of Level 3	-6,124	-6,506
Fixed maturities to short term investments classification change	0	0
Balance, end of period	5,288	11,877
Movement in total gains (losses) above relating to instruments still held at the reporting date	57	-515
Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
Level 3 assets
Balance, beginning of period	0	0
Realized gains (losses)	0	0
Movement in unrealized gains (losses)	0	0
Purchases and issuances	0	0
Sales	0	0
Settlements	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fixed maturities to short term investments classification change	0	0
Balance, end of period	0	0
Movement in total gains (losses) above relating to instruments still held at the reporting date	0	0
Short-term investments
Level 3 assets
Balance, beginning of period	2,015	0
Realized gains (losses)	0	-17
Movement in unrealized gains (losses)	-15	15
Purchases and issuances	0	2,017
Sales	0	0
Settlements	-2,000	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fixed maturities to short term investments classification change	0	0
Balance, end of period	0	2,015
Movement in total gains (losses) above relating to instruments still held at the reporting date	0	-2
Other investments
Level 3 assets
Balance, beginning of period	113,472	115,272
Realized gains (losses)	12,676	7,545
Movement in unrealized gains (losses)	538	4,095
Purchases and issuances	59,401	18,340
Sales	0	-1,237
Settlements	-25,498	-30,543
Transfers into Level 3	24,494	0
Transfers out of Level 3		0
Fixed maturities to short term investments classification change	0	0
Balance, end of period	185,083	113,472
Movement in total gains (losses) above relating to instruments still held at the reporting date	13,212	10,750
Derivative Contracts - Net
Level 3 liabilities
Balance, beginning of period	-29,110	-36,247
Realized gains (losses)	0	0
Movement in unrealized gains (losses)	-19,346	-7,137
Purchases and issuances	0	0
Sales	0	0
Settlements	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Balance, end of period	-9,764	-29,110
Movement in total gains (losses) above relating to instruments still held at the reporting date	$19,346	$7,137

Fair_Value_Measurements_Financ

Fair Value Measurements - Financial instruments not carried at fair value (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fixed maturities, held to maturity	$0	$2,858,695
Deposit Liabilities	1,245,367	1,509,243
Notes payable and debt	1,662,580	2,263,203
Carrying Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fixed maturities, held to maturity	0	2,858,695
Other investments - structured transactions	354,382	294,048
Financial Assets	354,382	3,152,743
Deposit Liabilities	1,245,367	1,509,243
Notes payable and debt	1,662,580	2,263,203
Financial Liabilities	2,907,947	3,772,446
Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fixed maturities, held to maturity	0	3,131,235
Other investments - structured transactions	371,625	296,799
Financial Assets	371,625	3,428,034
Deposit Liabilities	1,543,761	1,718,394
Notes payable and debt	1,897,854	2,429,412
Financial Liabilities	$3,441,615	$4,147,806

Fair_Value_Measurements_Narrat

Fair Value Measurements - Narrative (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, AFS, at fair value	$29,359,034	$27,500,136
Amortized cost of fixed maturities, available for sale	27,728,771	27,111,874
Spread on US Treasury rate for determining discount rate for fair value of deposit liabilities	29.50%	56.70%
Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, AFS, at fair value		11,125,830
Amortized cost of fixed maturities, available for sale		10,802,332
Medium-term Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, AFS, at fair value	79,900	154,600
Amortized cost of fixed maturities, available for sale	68,400	147,700
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments - structured transactions	$354,382	$294,048

Segment_Information_Statement_

Segment Information - Statement of earnings by segment (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Segment Reporting Information [Line Items]
Gross premiums written									$8,094,926		$7,741,135		$7,530,883
Net premiums written									5,944,841		6,199,404		6,281,451
Net premiums earned									5,895,070		6,309,521		6,090,437
Net losses and loss expenses									3,501,356		4,197,166		4,251,677
Acquisition costs									738,118		909,323		913,492
Operating expenses									1,069,689		957,841		921,300
Underwriting profit (loss)									585,907		245,191		3,968
Net investment income											885,789		940,680
Net results from structured products									54,209		23,791		5,257
Net fee income and other									-6,891		-5,692		3,768
Loss on sale of life reinsurance subsidiary									666,423		0		0
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments									107,462		87,777		14,098
Net realized and unrealized (gains) losses on derivative instruments									29,886		7,798		5,221
Net income (loss) from investment fund affiliates and operating affiliates									203,034		258,195		112,391
Exchange (gains) losses									-37,568		-28,243		10,545
Corporate operating expenses									220,165		209,454		204,502
Contribution from P&C and Corporate and Other									486,956		1,321,638		870,336
Interest expense									121,221		107,486		105,925
Non-controlling interests									80,498		76,731		79,255
Provision (benefit) for income tax									96,897		77,505		34,028
Net income (loss) attributable to ordinary shareholders									188,340		1,059,916		651,128
Exclude Life Funds Withheld Assets [Member]
Segment Reporting Information [Line Items]
Net investment income									721,016
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments									122,991
Life Funds Withheld Assets [Member]
Segment Reporting Information [Line Items]
Net investment income									129,575
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments									-15,529
Net realized and unrealized (gains) losses on derivative instruments									-488,222		0		0
Corporate and other
Segment Reporting Information [Line Items]
Gross premiums written									333,436	[1]	324,343	[1]	355,753	[1]
Net premiums written									177,632	[1]	295,422	[1]	324,432	[1]
Net premiums earned									177,632	[1]	295,422	[1]	324,459	[1]
Net losses and loss expenses									242,963	[1]	465,702	[1]	486,195	[1]
Acquisition costs									14,115	[1]	26,665	[1]	41,093	[1]
Operating expenses									10,693	[1],[2]	8,926	[1],[2]	9,335	[1],[2]
Underwriting profit (loss)									-90,139	[1]	-205,871	[1]	-212,164	[1]
Net investment income											286,645	[1],[3]	299,443	[1],[3]
Net results from structured products									0	[1],[4]	0	[1],[5]	0	[1],[6]
Net fee income and other									360	[1],[7]	1,305	[1],[7]	426	[1],[7]
Loss on sale of life reinsurance subsidiary									666,423	[1]
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments											1,985	[1]	-21,003	[1]
Net realized and unrealized (gains) losses on derivative instruments									29,886	[1]	7,798	[1]	5,221	[1]
Net income (loss) from investment fund affiliates and operating affiliates									203,034	[1],[8]	258,195	[1],[8]	112,391	[1],[8]
Exchange (gains) losses									-37,568	[1]	-28,243	[1]	10,545	[1]
Corporate operating expenses									220,165	[1]	209,454	[1]	204,502	[1]
Contribution from P&C and Corporate and Other									-929,872	[1]	168,846	[1]	-30,733	[1]
Interest expense									121,221	[1],[9]	107,486	[1],[9]	105,925	[1],[9]
Non-controlling interests									80,498	[1]	76,731	[1]	79,255	[1]
Provision (benefit) for income tax									96,897	[1]	77,505	[1]	34,028	[1]
Corporate and other \| Exclude Life Funds Withheld Assets [Member]
Segment Reporting Information [Line Items]
Net investment income									146,558	[1],[3]
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments									3,625	[1]
Corporate and other \| Life Funds Withheld Assets [Member]
Segment Reporting Information [Line Items]
Net investment income									129,575	[1]
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments									-15,529	[1]
Net realized and unrealized (gains) losses on derivative instruments									-488,222	[1]
Operating Segments [Member] \| Total P And C Segment [Member]
Segment Reporting Information [Line Items]
Gross premiums written									7,761,490		7,416,792		7,175,130
Net premiums written									5,767,209		5,903,982		5,957,019
Net premiums earned	1,413,161	1,453,673	1,438,076	1,412,528	1,510,727	1,550,629	1,488,497	1,464,246	5,717,438		6,014,099		5,765,978
Net losses and loss expenses									3,258,393		3,731,464		3,765,482
Acquisition costs									724,003		882,658		872,399
Operating expenses									1,058,996	[2]	948,915	[2]	911,965	[2]
Underwriting profit (loss)	218,851	144,375	167,946	144,874	101,450	76,900	92,124	180,588	676,046		451,062		216,132
Net investment income											599,144	[3]	641,237	[3]
Net results from structured products									54,209	[4]	23,791	[5]	5,257	[6]
Net fee income and other									-7,251	[7]	-6,997	[7]	3,342	[7]
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments											85,792		35,101
Net realized and unrealized (gains) losses on derivative instruments									0				0
Contribution from P&C and Corporate and Other									1,416,828		1,152,792		901,069
Ratios - P&C operations:
Loss and loss expense ratio									57.00%	[10]	62.00%	[10]	65.30%	[10]
Underwriting expense ratio									31.20%	[10]	30.50%	[10]	31.00%	[10]
Combined ratio									88.20%	[10]	92.50%	[10]	96.30%	[10]
Operating Segments [Member] \| Total P And C Segment [Member] \| Exclude Life Funds Withheld Assets [Member]
Segment Reporting Information [Line Items]
Net investment income									574,458	[3]
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments									119,366
Operating Segments [Member] \| Insurance Segment [Member]
Segment Reporting Information [Line Items]
Gross premiums written									5,976,011		5,523,181		5,166,973
Net premiums written									4,134,151		4,154,093		4,072,511
Net premiums earned									4,026,713		4,267,677		3,924,636
Net losses and loss expenses									2,543,108		2,829,999		2,691,056
Acquisition costs									393,319		529,270		504,227
Operating expenses									865,592	[2]	782,677	[2]	754,308	[2]
Underwriting profit (loss)									224,694		125,731		-24,955
Net results from structured products									43,710	[4]	15,562	[5]	20,978	[6]
Net fee income and other									-10,051	[7]	-9,317	[7]	850	[7]
Ratios - P&C operations:
Loss and loss expense ratio									63.20%	[10]	66.30%	[10]	68.60%	[10]
Underwriting expense ratio									31.20%	[10]	30.80%	[10]	32.00%	[10]
Combined ratio									94.40%	[10]	97.10%	[10]	100.60%	[10]
Operating Segments [Member] \| Reinsurance Segment [Member]
Segment Reporting Information [Line Items]
Gross premiums written									1,785,479		1,893,611		2,008,157
Net premiums written									1,633,058		1,749,889		1,884,508
Net premiums earned									1,690,725		1,746,422		1,841,342
Net losses and loss expenses									715,285		901,465		1,074,426
Acquisition costs									330,684		353,388		368,172
Operating expenses									193,404	[2]	166,238	[2]	157,657	[2]
Underwriting profit (loss)									451,352		325,331		241,087
Net results from structured products									10,499	[4]	8,229	[5]	-15,721	[6]
Net fee income and other									$2,800	[7]	$2,320	[7]	$2,492	[7]
Ratios - P&C operations:
Loss and loss expense ratio									42.30%	[10]	51.60%	[10]	58.40%	[10]
Underwriting expense ratio									31.00%	[10]	29.80%	[10]	28.50%	[10]
Combined ratio									73.30%	[10]	81.40%	[10]	86.90%	[10]

[1]	Corporate and Other includes other items of our revenue and expenditures that are not evaluated at the segment level for reporting purposes, as well as the Company's Run-Off Life Operations.
[2]	Operating expenses of the segments exclude Corporate operating expenses, shown separately.
[3]	Net investment income - excluding Life Funds Withheld Assets does not include net investment income related to the net results from structured products.
[4]	The net results from P&C structured products include net investment income and interest expense of $68.0 million and $12.9 million, respectively.
[5]	The net results from P&C structured products include net investment income and interest expense of $71.9 million and $48.0 million, respectively.
[6]	The net results from P&C structured products include net investment income and interest expense of $71.7 million and $66.3 million, respectively.
[7]	Net fee income and other includes operating expenses from the Company's loss prevention consulting services business.
[8]	The Company generally records the income related to the alternative funds and to the private investment and operating fund affiliates on a one-month and three-month lag, respectively.
[9]	Interest expense excludes interest expense related to deposit liabilities recorded in the Insurance and Reinsurance segments.
[10]	Ratios are based on net premiums earned from P&C operations.

Segment_Information_Net_premiu

Segment Information - Net premiums earned by line of business (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
P&C Operations:
P&C Operations									$5,717,438		$6,014,099		$5,765,978
Life Operations:
Life Operations									177,632		295,422		324,459
Net amount, premiums earned									5,895,070		6,309,521		6,090,437
Annuity
Life Operations:
Life Operations									53,363		122,715		126,912
Other life
Life Operations:
Life Operations									124,269		172,707		197,547
Total P And C Segment [Member] \| Professional
P&C Operations:
P&C Operations									1,256,643		1,576,365		1,563,643
Total P And C Segment [Member] \| Casualty
P&C Operations:
P&C Operations									1,722,907		1,702,007		1,476,919
Total P And C Segment [Member] \| Property catastrophe
P&C Operations:
P&C Operations									433,602		492,568		463,975
Total P And C Segment [Member] \| Property
P&C Operations:
P&C Operations									1,100,439		1,105,383		1,103,030
Total P And C Segment [Member] \| Marine, energy, aviation and satellite
P&C Operations:
P&C Operations									95,745		94,797		147,362
Total P And C Segment [Member] \| Specialty
P&C Operations:
P&C Operations									737,281		732,042		708,568
Total P And C Segment [Member] \| Other
P&C Operations:
P&C Operations									370,821	[1]	310,937	[1]	302,481	[1]
Corporate and other
Life Operations:
Life Operations									177,632		295,422		324,459
Net amount, premiums earned									177,632	[2]	295,422	[2]	324,459	[2]
Corporate and other \| Annuity
Life Operations:
Life Operations									53,363		122,715		126,912
Corporate and other \| Other life
Life Operations:
Life Operations									124,269		172,707		197,547
Operating Segments [Member] \| Total P And C Segment [Member]
Life Operations:
Net amount, premiums earned	1,413,161	1,453,673	1,438,076	1,412,528	1,510,727	1,550,629	1,488,497	1,464,246	5,717,438		6,014,099		5,765,978
Operating Segments [Member] \| Insurance Segment [Member]
P&C Operations:
P&C Operations									4,026,713		4,267,677		3,924,636
Life Operations:
Net amount, premiums earned									4,026,713		4,267,677		3,924,636
Operating Segments [Member] \| Insurance Segment [Member] \| Professional
P&C Operations:
P&C Operations									1,075,420		1,370,196		1,350,319
Operating Segments [Member] \| Insurance Segment [Member] \| Casualty
P&C Operations:
P&C Operations									1,422,684		1,389,851		1,165,753
Operating Segments [Member] \| Insurance Segment [Member] \| Property catastrophe
P&C Operations:
P&C Operations									0		0		0
Operating Segments [Member] \| Insurance Segment [Member] \| Property
P&C Operations:
P&C Operations									544,856		544,278		489,739
Operating Segments [Member] \| Insurance Segment [Member] \| Marine, energy, aviation and satellite
P&C Operations:
P&C Operations									0		0		0
Operating Segments [Member] \| Insurance Segment [Member] \| Specialty
P&C Operations:
P&C Operations									737,281		732,042		708,568
Operating Segments [Member] \| Insurance Segment [Member] \| Other
P&C Operations:
P&C Operations									246,472	[1]	231,310	[1]	210,257	[1]
Operating Segments [Member] \| Reinsurance Segment [Member]
P&C Operations:
P&C Operations									1,690,725		1,746,422		1,841,342
Life Operations:
Net amount, premiums earned									1,690,725		1,746,422		1,841,342
Operating Segments [Member] \| Reinsurance Segment [Member] \| Professional
P&C Operations:
P&C Operations									181,223		206,169		213,324
Operating Segments [Member] \| Reinsurance Segment [Member] \| Casualty
P&C Operations:
P&C Operations									300,223		312,156		311,166
Operating Segments [Member] \| Reinsurance Segment [Member] \| Property catastrophe
P&C Operations:
P&C Operations									433,602		492,568		463,975
Operating Segments [Member] \| Reinsurance Segment [Member] \| Property
P&C Operations:
P&C Operations									555,583		561,105		613,291
Operating Segments [Member] \| Reinsurance Segment [Member] \| Marine, energy, aviation and satellite
P&C Operations:
P&C Operations									95,745		94,797		147,362
Operating Segments [Member] \| Reinsurance Segment [Member] \| Specialty
P&C Operations:
P&C Operations									0		0		0
Operating Segments [Member] \| Reinsurance Segment [Member] \| Other
P&C Operations:
P&C Operations									$124,349	[1]	$79,627	[1]	$92,224	[1]

[1]	Other within the Insurance segment includes: excess and surplus, programs, surety, structured indemnity and certain discontinued lines. Other within the Reinsurance segment includes: whole account contracts, accident and health and other lines.
[2]	Corporate and Other includes other items of our revenue and expenditures that are not evaluated at the segment level for reporting purposes, as well as the Company's Run-Off Life Operations.

Segment_Information_Net_premiu1

Segment Information - Net premiums written by geographical location (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Net premiums written	$5,944,841	$6,199,404	$6,281,451
Life operations
Revenues from External Customers and Long-Lived Assets [Line Items]
Net premiums written	177,632	295,422	324,432
Life operations \| Bermuda
Revenues from External Customers and Long-Lived Assets [Line Items]
Net premiums written	91,979	117,948	129,997
Life operations \| Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Net premiums written	85,653	177,474	194,435
Operating Segments [Member] \| Total P And C Segment [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net premiums written	5,767,209	5,903,982	5,957,019
Operating Segments [Member] \| Total P And C Segment [Member] \| Bermuda
Revenues from External Customers and Long-Lived Assets [Line Items]
Net premiums written	636,109	658,041	644,566
Operating Segments [Member] \| Total P And C Segment [Member] \| United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net premiums written	2,528,196	2,650,916	2,626,855
Operating Segments [Member] \| Total P And C Segment [Member] \| Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Net premiums written	2,124,117	2,111,065	2,202,209
Operating Segments [Member] \| Total P And C Segment [Member] \| Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Net premiums written	$478,787	$483,960	$483,389

Segment_Information_Narrative_

Segment Information - Narrative (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	segments	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Number of Operating Segments	2
Net results from structured products	$54,209	$23,791	$5,257
Alternative funds
Segment Reporting Information [Line Items]
Alternative investments, timelag for reporting	1 month
Operating affiliates
Segment Reporting Information [Line Items]
Alternative investments, timelag for reporting	3 months
Total P And C Segment [Member] \| Net Investment Income [Member]
Segment Reporting Information [Line Items]
Net results from structured products	68,000	71,900	71,700
Total P And C Segment [Member] \| Interest Expense [Member]
Segment Reporting Information [Line Items]
Net results from structured products	($12,900)	($48,000)	($66,300)

Investments_Cost_amortized_cos

Investments - Cost (amortized cost for fixed maturities and short-term investments), fair value, gross unrealized gains, gross unrealized (losses), and OTTI recorded in AOCI (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Fixed maturities - AFS
Amortized cost of Fixed maturities	$27,728,771		$27,111,874
Available for sale fixed income securities, gross unrealized gains			807,684
Available for sale fixed income securities, gross unrealized losses			-419,422
Fixed maturities, AFS, at fair value	29,359,034		27,500,136
Gross Unrealized Losses Non-credit Related OTTI	-76,720	[1]	-86,882	[1]
Short Term Investments
Short-term investments, cost or amortized cost	257,221		455,470
Short -term investments, Gross unrealized gains			962
Short -term investments, Gross unrealized losses			-144
Short-term investments, AFS, at fair value			456,288
Equity securities
Cost of equity securities	763,833		903,201
Equity securities, gross unrealized gains			154,506
Equity securities, gross unrealized losses			-17,470
Equity securities, AFS, at fair value	868,292		1,040,237
Total investments - AFS
Cost or Amortized cost of total investments - AFS	28,749,825		28,470,545
Available for sale securities, gross unrealized gain	1,947,804		963,152
Available for sale securities, gross unrealized loss	-213,576		-437,036
Total investments available for sale	30,484,053		28,996,661
HTM securities
Fixed maturities, held to maturity	0		2,858,695
Fixed maturities, held to maturity, gross unrealized losses	0
Fair value of held to maturity securities	0		3,131,235
Fixed maturities, trading, at fair value	1,171		0
US Government And Government Related [Member]
Fixed maturities - AFS
Amortized cost of Fixed maturities			2,484,193
Available for sale fixed income securities, gross unrealized gains			51,701
Available for sale fixed income securities, gross unrealized losses			-34,043
Fixed maturities, AFS, at fair value			2,501,851
Gross Unrealized Losses Non-credit Related OTTI			0	[1]
HTM securities
Fixed maturities, held to maturity			10,993
Fixed maturities, held to maturity, gross unrealized gains			629
Fixed maturities, held to maturity, gross unrealized losses			0
Fair value of held to maturity securities			11,622
Corporate
Fixed maturities - AFS
Amortized cost of Fixed maturities			10,802,332
Available for sale fixed income securities, gross unrealized gains			433,097	[2]
Available for sale fixed income securities, gross unrealized losses			-109,599	[2]
Fixed maturities, AFS, at fair value			11,125,830
Gross Unrealized Losses Non-credit Related OTTI			-4,758	[1]
HTM securities
Fixed maturities, held to maturity			1,386,863
Fixed maturities, held to maturity, gross unrealized gains			113,179
Fixed maturities, held to maturity, gross unrealized losses			-968
Fair value of held to maturity securities			1,499,074
RMBS - Agency
Fixed maturities - AFS
Amortized cost of Fixed maturities			3,540,101
Available for sale fixed income securities, gross unrealized gains			68,098
Available for sale fixed income securities, gross unrealized losses			-62,077
Fixed maturities, AFS, at fair value			3,546,122
Gross Unrealized Losses Non-credit Related OTTI			0	[1]
RMBS - Non-Agency
Fixed maturities - AFS
Amortized cost of Fixed maturities			396,798
Available for sale fixed income securities, gross unrealized gains			33,096
Available for sale fixed income securities, gross unrealized losses			-31,126
Fixed maturities, AFS, at fair value			398,768
Gross Unrealized Losses Non-credit Related OTTI			-74,528	[1]
HTM securities
Fixed maturities, held to maturity			66,987
Fixed maturities, held to maturity, gross unrealized gains			4,985
Fixed maturities, held to maturity, gross unrealized losses			0
Fair value of held to maturity securities			71,972
CMBS
Fixed maturities - AFS
Amortized cost of Fixed maturities			1,223,313
Available for sale fixed income securities, gross unrealized gains			39,255
Available for sale fixed income securities, gross unrealized losses			-15,773
Fixed maturities, AFS, at fair value			1,246,795
Gross Unrealized Losses Non-credit Related OTTI			-2,753	[1]
HTM securities
Fixed maturities, held to maturity			144,924
Fixed maturities, held to maturity, gross unrealized gains			11,864
Fixed maturities, held to maturity, gross unrealized losses			0
Fair value of held to maturity securities			156,788
Collateralized debt obligations ('CDO') [Member]
Fixed maturities - AFS
Amortized cost of Fixed maturities			754,414
Available for sale fixed income securities, gross unrealized gains			5,833
Available for sale fixed income securities, gross unrealized losses			-42,934
Fixed maturities, AFS, at fair value			717,313
Gross Unrealized Losses Non-credit Related OTTI			-2,036	[1]
Other asset-backed securities
Fixed maturities - AFS
Amortized cost of Fixed maturities			1,210,384
Available for sale fixed income securities, gross unrealized gains			40,560	[2]
Available for sale fixed income securities, gross unrealized losses			-8,840	[2]
Fixed maturities, AFS, at fair value			1,242,104
Gross Unrealized Losses Non-credit Related OTTI			-2,807	[1]
HTM securities
Fixed maturities, held to maturity			106,540
Fixed maturities, held to maturity, gross unrealized gains			6,908
Fixed maturities, held to maturity, gross unrealized losses			0
Fair value of held to maturity securities			113,448
U.S. States and political subdivisions of the States [Member]
Fixed maturities - AFS
Amortized cost of Fixed maturities			1,821,499
Available for sale fixed income securities, gross unrealized gains			55,083
Available for sale fixed income securities, gross unrealized losses			-30,770
Fixed maturities, AFS, at fair value			1,845,812
Gross Unrealized Losses Non-credit Related OTTI			0	[1]
Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
Fixed maturities - AFS
Amortized cost of Fixed maturities			4,878,840
Available for sale fixed income securities, gross unrealized gains			80,961
Available for sale fixed income securities, gross unrealized losses			-84,260
Fixed maturities, AFS, at fair value			4,875,541
Gross Unrealized Losses Non-credit Related OTTI			0	[1]
HTM securities
Fixed maturities, held to maturity			1,142,388
Fixed maturities, held to maturity, gross unrealized gains			136,585
Fixed maturities, held to maturity, gross unrealized losses			-642
Fair value of held to maturity securities			1,278,331
HTM
HTM securities
Fixed maturities, held to maturity	0		2,858,695
Fixed maturities, held to maturity, gross unrealized gains	0		274,150
Fixed maturities, held to maturity, gross unrealized losses			-1,610
Fair value of held to maturity securities	0		3,131,235
Exclude Life Funds Withheld Assets [Member]
Fixed maturities - AFS
Amortized cost of Fixed maturities	23,427,432		27,111,874
Available for sale fixed income securities, gross unrealized gains	936,840
Available for sale fixed income securities, gross unrealized losses	-186,803
Fixed maturities, AFS, at fair value	24,177,469		27,500,136
Gross Unrealized Losses Non-credit Related OTTI	-76,720	[1]
Short Term Investments
Short-term investments, cost or amortized cost	257,221
Short -term investments, Gross unrealized gains	49
Short -term investments, Gross unrealized losses	-543
Short-term investments, AFS, at fair value	256,727
Equity securities
Cost of equity securities	763,833
Equity securities, gross unrealized gains	130,689
Equity securities, gross unrealized losses	-26,230
Equity securities, AFS, at fair value	868,292
Total investments - AFS
Cost or Amortized cost of total investments - AFS	24,448,486
Available for sale securities, gross unrealized gain	1,067,578
Available for sale securities, gross unrealized loss	-213,576
Total investments available for sale	25,302,488
Exclude Life Funds Withheld Assets [Member] \| US Government And Government Related [Member]
Fixed maturities - AFS
Amortized cost of Fixed maturities	2,100,851
Available for sale fixed income securities, gross unrealized gains	77,889
Available for sale fixed income securities, gross unrealized losses	-6,787
Fixed maturities, AFS, at fair value	2,171,953
Gross Unrealized Losses Non-credit Related OTTI	0	[1]
Exclude Life Funds Withheld Assets [Member] \| Corporate
Fixed maturities - AFS
Amortized cost of Fixed maturities	8,462,130
Available for sale fixed income securities, gross unrealized gains	365,805
Available for sale fixed income securities, gross unrealized losses	-49,562
Fixed maturities, AFS, at fair value	8,778,373
Gross Unrealized Losses Non-credit Related OTTI	-3,309	[1]
Exclude Life Funds Withheld Assets [Member] \| RMBS - Agency
Fixed maturities - AFS
Amortized cost of Fixed maturities	3,625,171
Available for sale fixed income securities, gross unrealized gains	114,188
Available for sale fixed income securities, gross unrealized losses	-10,783
Fixed maturities, AFS, at fair value	3,728,576
Gross Unrealized Losses Non-credit Related OTTI	0	[1]
Exclude Life Funds Withheld Assets [Member] \| RMBS - Non-Agency
Fixed maturities - AFS
Amortized cost of Fixed maturities	404,398
Available for sale fixed income securities, gross unrealized gains	41,108
Available for sale fixed income securities, gross unrealized losses	-18,155
Fixed maturities, AFS, at fair value	427,351
Gross Unrealized Losses Non-credit Related OTTI	-67,918	[1]
Exclude Life Funds Withheld Assets [Member] \| CMBS
Fixed maturities - AFS
Amortized cost of Fixed maturities	1,033,819
Available for sale fixed income securities, gross unrealized gains	23,987
Available for sale fixed income securities, gross unrealized losses	-5,262
Fixed maturities, AFS, at fair value	1,052,544
Gross Unrealized Losses Non-credit Related OTTI	-2,033	[1]
Exclude Life Funds Withheld Assets [Member] \| Collateralized debt obligations ('CDO') [Member]
Fixed maturities - AFS
Amortized cost of Fixed maturities	717,544
Available for sale fixed income securities, gross unrealized gains	1,659
Available for sale fixed income securities, gross unrealized losses	-27,169
Fixed maturities, AFS, at fair value	692,034
Gross Unrealized Losses Non-credit Related OTTI	-1,663	[1]
Exclude Life Funds Withheld Assets [Member] \| Other asset-backed securities
Fixed maturities - AFS
Amortized cost of Fixed maturities	1,028,528
Available for sale fixed income securities, gross unrealized gains	42,810	[3]
Available for sale fixed income securities, gross unrealized losses	-6,045	[3]
Fixed maturities, AFS, at fair value	1,065,293
Gross Unrealized Losses Non-credit Related OTTI	-1,797	[1]
Exclude Life Funds Withheld Assets [Member] \| U.S. States and political subdivisions of the States [Member]
Fixed maturities - AFS
Amortized cost of Fixed maturities	1,892,566
Available for sale fixed income securities, gross unrealized gains	129,910
Available for sale fixed income securities, gross unrealized losses	-1,204
Fixed maturities, AFS, at fair value	2,021,272
Gross Unrealized Losses Non-credit Related OTTI	0	[1]
Exclude Life Funds Withheld Assets [Member] \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
Fixed maturities - AFS
Amortized cost of Fixed maturities	4,162,425
Available for sale fixed income securities, gross unrealized gains	139,484
Available for sale fixed income securities, gross unrealized losses	-61,836
Fixed maturities, AFS, at fair value	4,240,073
Gross Unrealized Losses Non-credit Related OTTI	0	[1]
Life Funds Withheld Assets [Member]
Fixed maturities - AFS
Amortized cost of Fixed maturities	4,301,339		0
Available for sale fixed income securities, gross unrealized gains	880,226
Available for sale fixed income securities, gross unrealized losses	0
Fixed maturities, AFS, at fair value	5,181,565		0
Gross Unrealized Losses Non-credit Related OTTI	0	[1]
HTM securities
Trading Securities, Cost	1,180
Fixed maturities, trading, at fair value	1,171
Life Funds Withheld Assets [Member] \| US Government And Government Related [Member]
Fixed maturities - AFS
Amortized cost of Fixed maturities	14,866
Available for sale fixed income securities, gross unrealized gains	3,858
Available for sale fixed income securities, gross unrealized losses	0
Fixed maturities, AFS, at fair value	18,724
Gross Unrealized Losses Non-credit Related OTTI	0	[1]
Life Funds Withheld Assets [Member] \| Corporate
Fixed maturities - AFS
Amortized cost of Fixed maturities	2,407,849
Available for sale fixed income securities, gross unrealized gains	410,131
Available for sale fixed income securities, gross unrealized losses	0
Fixed maturities, AFS, at fair value	2,817,980
Gross Unrealized Losses Non-credit Related OTTI	0	[1]
HTM securities
Trading Securities, Cost	1,180
Fixed maturities, trading, at fair value	1,171
Life Funds Withheld Assets [Member] \| RMBS - Agency
Fixed maturities - AFS
Amortized cost of Fixed maturities	3,301
Available for sale fixed income securities, gross unrealized gains	481
Available for sale fixed income securities, gross unrealized losses	0
Fixed maturities, AFS, at fair value	3,782
Gross Unrealized Losses Non-credit Related OTTI	0	[1]
Life Funds Withheld Assets [Member] \| RMBS - Non-Agency
Fixed maturities - AFS
Amortized cost of Fixed maturities	71,075
Available for sale fixed income securities, gross unrealized gains	14,260
Available for sale fixed income securities, gross unrealized losses	0
Fixed maturities, AFS, at fair value	85,335
Gross Unrealized Losses Non-credit Related OTTI	0	[1]
Life Funds Withheld Assets [Member] \| CMBS
Fixed maturities - AFS
Amortized cost of Fixed maturities	168,886
Available for sale fixed income securities, gross unrealized gains	24,281
Available for sale fixed income securities, gross unrealized losses	0
Fixed maturities, AFS, at fair value	193,167
Gross Unrealized Losses Non-credit Related OTTI	0	[1]
Life Funds Withheld Assets [Member] \| Collateralized debt obligations ('CDO') [Member]
Fixed maturities - AFS
Amortized cost of Fixed maturities	0
Available for sale fixed income securities, gross unrealized gains	0
Available for sale fixed income securities, gross unrealized losses	0
Fixed maturities, AFS, at fair value	0
Gross Unrealized Losses Non-credit Related OTTI	0	[1]
Life Funds Withheld Assets [Member] \| Other asset-backed securities
Fixed maturities - AFS
Amortized cost of Fixed maturities	238,168
Available for sale fixed income securities, gross unrealized gains	35,373
Available for sale fixed income securities, gross unrealized losses	0
Fixed maturities, AFS, at fair value	273,541
Gross Unrealized Losses Non-credit Related OTTI	0	[1]
Life Funds Withheld Assets [Member] \| U.S. States and political subdivisions of the States [Member]
Fixed maturities - AFS
Amortized cost of Fixed maturities	0
Available for sale fixed income securities, gross unrealized gains	0
Available for sale fixed income securities, gross unrealized losses	0
Fixed maturities, AFS, at fair value	0
Gross Unrealized Losses Non-credit Related OTTI	0	[1]
Life Funds Withheld Assets [Member] \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
Fixed maturities - AFS
Amortized cost of Fixed maturities	1,397,194
Available for sale fixed income securities, gross unrealized gains	391,842
Available for sale fixed income securities, gross unrealized losses	0
Fixed maturities, AFS, at fair value	1,789,036
Gross Unrealized Losses Non-credit Related OTTI	$0	[1]

[1]	Represents the non-credit component of OTTI losses, adjusted for subsequent sales of securities. It does not include the change in fair value subsequent to the impairment measurement date.
[2]	Included are certain medium term notes supported primarily by pools of European investment grade credit with varying degrees of leverage. The notes have a fair value of $154.6 million and an amortized cost of $147.7 million. These notes allow the investor to participate in cash flows of the underlying bonds including certain residual values, which could serve to either decrease or increase the ultimate values of these notes.
[3]	Included are certain medium term notes supported primarily by pools of European investment grade credit with varying degrees of leverage. The notes have a fair value of $79.9 million and an amortized cost of $68.4 million. These notes allow the investor to participate in cash flows of the underlying bonds including certain residual values, which could serve to either decrease or increase the ultimate values of these notes.

Investments_Contractual_maturi

Investments - Contractual maturities of income securities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
AFS securities
Amortized cost of Fixed maturities	$27,728,771	$27,111,874
Fixed maturities, at fair value	29,359,034	27,500,136
Fixed maturities - HTM
Due less than one year, amortized cost	0	65,651
Due less than one year, fair value	0	66,766
Due after 1 through 5 years, amortized cost	0	240,802
Due after 1 through 5 years, fair value	0	255,322
Due after 5 through 10 years, amortized cost	0	455,633
Due after 5 through 10 years, fair value	0	492,095
Due after 10 years, amortized cost	0	1,778,158
Due after 10 years, fair value	0	1,974,844
Subtotal - amortized cost	0	2,540,244
Subtotal - fair value	0	2,789,027
Mortage and asset-backed securities - amortized cost	0	318,451
Mortgage and asset-backed securities - fair value	0	342,208
Fixed maturities, held to maturity	0	2,858,695
Held to maturity, fair value	0	3,131,235
RMBS - Agency
AFS securities
Amortized cost of Fixed maturities		3,540,101
Fixed maturities, at fair value		3,546,122
RMBS - Non-Agency
AFS securities
Amortized cost of Fixed maturities		396,798
Fixed maturities, at fair value		398,768
Fixed maturities - HTM
Mortage and asset-backed securities - amortized cost	0	66,987
Mortgage and asset-backed securities - fair value	0	71,972
Fixed maturities, held to maturity		66,987
Held to maturity, fair value		71,972
CMBS
AFS securities
Amortized cost of Fixed maturities		1,223,313
Fixed maturities, at fair value		1,246,795
Fixed maturities - HTM
Mortage and asset-backed securities - amortized cost	0	144,924
Mortgage and asset-backed securities - fair value	0	156,788
Fixed maturities, held to maturity		144,924
Held to maturity, fair value		156,788
Collateralized debt obligations ('CDO') [Member]
AFS securities
Amortized cost of Fixed maturities		754,414
Fixed maturities, at fair value		717,313
Other asset-backed securities
AFS securities
Amortized cost of Fixed maturities		1,210,384
Fixed maturities, at fair value		1,242,104
Fixed maturities - HTM
Mortage and asset-backed securities - amortized cost	0	106,540
Mortgage and asset-backed securities - fair value	0	113,448
Fixed maturities, held to maturity		106,540
Held to maturity, fair value		113,448
Exclude Life Funds Withheld Assets [Member]
AFS securities
Due less than one year, amortized cost	1,972,224	2,052,251
Due less than one year, fair value	1,980,429	2,060,365
Due after 1 through 5 years, amortized cost	8,919,037	10,075,087
Due after 1 through 5 years, fair value	9,113,651	10,305,986
Due after 5 through 10 years, amortized cost	4,232,396	5,474,120
Due after 5 through 10 years, fair value	4,412,569	5,507,450
Due after 10 years, amortized cost	1,494,315	2,385,406
Due after 10 years, fair value	1,705,022	2,475,233
Subtotal - amortized cost	16,617,972	19,986,864
Subtotal - fair value	17,211,671	20,349,034
Mortgage and asset-backed securities - amortized cost	6,809,460	7,125,010
Mortgage and asset-backed securities - fair value	6,965,798	7,151,102
Amortized cost of Fixed maturities	23,427,432	27,111,874
Fixed maturities, at fair value	24,177,469	27,500,136
Exclude Life Funds Withheld Assets [Member] \| RMBS - Agency
AFS securities
Mortgage and asset-backed securities - amortized cost	3,625,171	3,540,101
Mortgage and asset-backed securities - fair value	3,728,576	3,546,122
Amortized cost of Fixed maturities	3,625,171
Fixed maturities, at fair value	3,728,576
Exclude Life Funds Withheld Assets [Member] \| RMBS - Non-Agency
AFS securities
Mortgage and asset-backed securities - amortized cost	404,398	396,798
Mortgage and asset-backed securities - fair value	427,351	398,768
Amortized cost of Fixed maturities	404,398
Fixed maturities, at fair value	427,351
Exclude Life Funds Withheld Assets [Member] \| CMBS
AFS securities
Mortgage and asset-backed securities - amortized cost	1,033,819	1,223,313
Mortgage and asset-backed securities - fair value	1,052,544	1,246,795
Amortized cost of Fixed maturities	1,033,819
Fixed maturities, at fair value	1,052,544
Exclude Life Funds Withheld Assets [Member] \| Collateralized debt obligations ('CDO') [Member]
AFS securities
Mortgage and asset-backed securities - amortized cost	717,544	754,414
Mortgage and asset-backed securities - fair value	692,034	717,313
Amortized cost of Fixed maturities	717,544
Fixed maturities, at fair value	692,034
Exclude Life Funds Withheld Assets [Member] \| Other asset-backed securities
AFS securities
Mortgage and asset-backed securities - amortized cost	1,028,528	1,210,384
Mortgage and asset-backed securities - fair value	1,065,293	1,242,104
Amortized cost of Fixed maturities	1,028,528
Fixed maturities, at fair value	1,065,293
Life Funds Withheld Assets [Member]
AFS securities
Due less than one year, amortized cost	117,048	0
Due less than one year, fair value	125,326	0
Due after 1 through 5 years, amortized cost	638,526	0
Due after 1 through 5 years, fair value	685,787	0
Due after 5 through 10 years, amortized cost	1,004,698	0
Due after 5 through 10 years, fair value	1,165,348	0
Due after 10 years, amortized cost	2,059,637	0
Due after 10 years, fair value	2,649,279	0
Subtotal - amortized cost	3,819,909	0
Subtotal - fair value	4,625,740	0
Mortgage and asset-backed securities - amortized cost	481,430	0
Mortgage and asset-backed securities - fair value	555,825	0
Amortized cost of Fixed maturities	4,301,339	0
Fixed maturities, at fair value	5,181,565	0
Life Funds Withheld Assets [Member] \| RMBS - Agency
AFS securities
Mortgage and asset-backed securities - amortized cost	3,301	0
Mortgage and asset-backed securities - fair value	3,782	0
Amortized cost of Fixed maturities	3,301
Fixed maturities, at fair value	3,782
Life Funds Withheld Assets [Member] \| RMBS - Non-Agency
AFS securities
Mortgage and asset-backed securities - amortized cost	71,075	0
Mortgage and asset-backed securities - fair value	85,335	0
Amortized cost of Fixed maturities	71,075
Fixed maturities, at fair value	85,335
Life Funds Withheld Assets [Member] \| CMBS
AFS securities
Mortgage and asset-backed securities - amortized cost	168,886	0
Mortgage and asset-backed securities - fair value	193,167	0
Amortized cost of Fixed maturities	168,886
Fixed maturities, at fair value	193,167
Life Funds Withheld Assets [Member] \| Collateralized debt obligations ('CDO') [Member]
AFS securities
Mortgage and asset-backed securities - amortized cost	0	0
Mortgage and asset-backed securities - fair value	0	0
Amortized cost of Fixed maturities	0
Fixed maturities, at fair value	0
Life Funds Withheld Assets [Member] \| Other asset-backed securities
AFS securities
Mortgage and asset-backed securities - amortized cost	238,168	0
Mortgage and asset-backed securities - fair value	273,541	0
Amortized cost of Fixed maturities	238,168
Fixed maturities, at fair value	273,541
Cost [Member] \| Life Funds Withheld Assets [Member]
Trading Securities [Abstract]
Trading securities due after 1 through 5 years	0	0
Trading securities due after 5 through 10 years	1,180	0
Trading securities due after 10 years	0	0
Trading securities due less than one year	0	0
Total trading fixed maturities	1,180	0
Fair value [Member] \| Life Funds Withheld Assets [Member]
Trading Securities [Abstract]
Trading securities due after 1 through 5 years	0	0
Trading securities due after 5 through 10 years	1,171	0
Trading securities due after 10 years	0	0
Trading securities due less than one year	0	0
Total trading fixed maturities	$1,171	$0

Investments_Analysis_of_contin

Investments - Analysis of continual unrealized loss position (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
HTM securities
Less than 12 months Fair Value	$0	$46,034
Less than 12 month Gross Unrealized Losses	0	-941
Equal to or greater than 12 months Fair Value	0	12,536
Equal to or greater than 12 months Gross Unrealized Losses	0	-669
Fixed Maturities And Short Term Investments Available For Sale [Member]
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value		8,871,868
Less than 12 month Gross Unrealized Losses		-230,109
Equal to or greater than 12 months Fair Value		2,117,444
Equal to or greater than 12 months Gross Unrealized Losses		-189,457
U.S. Government and Government - Related/Supported [Member]
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value		1,333,704
Less than 12 month Gross Unrealized Losses		-30,474
Equal to or greater than 12 months Fair Value		44,158
Equal to or greater than 12 months Gross Unrealized Losses		-3,614
Corporate
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value		2,756,235
Less than 12 month Gross Unrealized Losses		-59,497
Equal to or greater than 12 months Fair Value		513,106
Equal to or greater than 12 months Gross Unrealized Losses		-50,160
HTM securities
Less than 12 months Fair Value		46,034
Less than 12 month Gross Unrealized Losses		-941
Equal to or greater than 12 months Fair Value		642
Equal to or greater than 12 months Gross Unrealized Losses		-27
RMBS - Agency
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value		1,485,261
Less than 12 month Gross Unrealized Losses		-50,362
Equal to or greater than 12 months Fair Value		169,704
Equal to or greater than 12 months Gross Unrealized Losses		-11,715
RMBS - Non-Agency
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value		14,204
Less than 12 month Gross Unrealized Losses		-604
Equal to or greater than 12 months Fair Value		240,946
Equal to or greater than 12 months Gross Unrealized Losses		-30,522
CMBS
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value		432,820
Less than 12 month Gross Unrealized Losses		-6,816
Equal to or greater than 12 months Fair Value		107,192
Equal to or greater than 12 months Gross Unrealized Losses		-8,957
Collateralized debt obligations ('CDO') [Member]
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value		58,239
Less than 12 month Gross Unrealized Losses		-217
Equal to or greater than 12 months Fair Value		574,613
Equal to or greater than 12 months Gross Unrealized Losses		-42,717
Other asset-backed securities
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value		196,639
Less than 12 month Gross Unrealized Losses		-2,149
Equal to or greater than 12 months Fair Value		96,528
Equal to or greater than 12 months Gross Unrealized Losses		-6,691
U.S. States and political subdivisions of the States [Member]
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value		463,974
Less than 12 month Gross Unrealized Losses		-23,124
Equal to or greater than 12 months Fair Value		64,324
Equal to or greater than 12 months Gross Unrealized Losses		-7,646
Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value		2,130,792
Less than 12 month Gross Unrealized Losses		-56,866
Equal to or greater than 12 months Fair Value		306,873
Equal to or greater than 12 months Gross Unrealized Losses		-27,435
HTM securities
Less than 12 months Fair Value		0
Less than 12 month Gross Unrealized Losses		0
Equal to or greater than 12 months Fair Value		11,894
Equal to or greater than 12 months Gross Unrealized Losses		-642
Equity securities
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value	191,193	155,453
Less than 12 month Gross Unrealized Losses	-26,230	-17,470
Equal to or greater than 12 months Fair Value	0	0
Equal to or greater than 12 months Gross Unrealized Losses	0	0
Exclude Life Funds Withheld Assets [Member] \| Fixed Maturities And Short Term Investments Available For Sale [Member]
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value	2,896,210
Less than 12 month Gross Unrealized Losses	-61,772
Equal to or greater than 12 months Fair Value	2,745,705
Equal to or greater than 12 months Gross Unrealized Losses	-125,574
Exclude Life Funds Withheld Assets [Member] \| U.S. Government and Government - Related/Supported [Member]
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value	251,091
Less than 12 month Gross Unrealized Losses	-1,196
Equal to or greater than 12 months Fair Value	342,890
Equal to or greater than 12 months Gross Unrealized Losses	-5,603
Exclude Life Funds Withheld Assets [Member] \| Corporate
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value	1,337,470
Less than 12 month Gross Unrealized Losses	-33,881
Equal to or greater than 12 months Fair Value	424,221
Equal to or greater than 12 months Gross Unrealized Losses	-15,754
Exclude Life Funds Withheld Assets [Member] \| RMBS - Agency
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value	134,535
Less than 12 month Gross Unrealized Losses	-220
Equal to or greater than 12 months Fair Value	512,652
Equal to or greater than 12 months Gross Unrealized Losses	-10,563
Exclude Life Funds Withheld Assets [Member] \| RMBS - Non-Agency
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value	45,378
Less than 12 month Gross Unrealized Losses	-1,358
Equal to or greater than 12 months Fair Value	202,700
Equal to or greater than 12 months Gross Unrealized Losses	-16,797
Exclude Life Funds Withheld Assets [Member] \| CMBS
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value	78,356
Less than 12 month Gross Unrealized Losses	-385
Equal to or greater than 12 months Fair Value	169,065
Equal to or greater than 12 months Gross Unrealized Losses	-4,877
Exclude Life Funds Withheld Assets [Member] \| Collateralized debt obligations ('CDO') [Member]
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value	249,803
Less than 12 month Gross Unrealized Losses	-2,666
Equal to or greater than 12 months Fair Value	414,516
Equal to or greater than 12 months Gross Unrealized Losses	-24,503
Exclude Life Funds Withheld Assets [Member] \| Other asset-backed securities
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value	143,044
Less than 12 month Gross Unrealized Losses	-2,813
Equal to or greater than 12 months Fair Value	57,544
Equal to or greater than 12 months Gross Unrealized Losses	-3,232
Exclude Life Funds Withheld Assets [Member] \| U.S. States and political subdivisions of the States [Member]
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value	32,187
Less than 12 month Gross Unrealized Losses	-210
Equal to or greater than 12 months Fair Value	63,695
Equal to or greater than 12 months Gross Unrealized Losses	-994
Exclude Life Funds Withheld Assets [Member] \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
Fixed maturities and short-term investments - AFS:
Less than 12 months Fair Value	624,346
Less than 12 month Gross Unrealized Losses	-19,043
Equal to or greater than 12 months Fair Value	558,422
Equal to or greater than 12 months Gross Unrealized Losses	($43,251)

Investments_Analysis_of_net_in

Investments - Analysis of net investment income (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net Investment Income [Line Items]
Equity securities and other investments	$42,252	$35,388	$29,807
Funds withheld	14,583	12,783	12,090
Total gross investment income	996,374	1,030,446	1,088,152
Investment expenses	-77,749	-72,730	-75,804
Net investment income	918,625	957,716	1,012,348
Exclude Life Funds Withheld Assets [Member]
Net Investment Income [Line Items]
Fixed maturities, short term investments and cash equivalents	809,964	982,275	1,046,255
Net investment income	789,050	957,716	1,012,348
Life Funds Withheld Assets [Member]
Net Investment Income [Line Items]
Fixed maturities, short term investments and cash equivalents	129,575	0	0
Net investment income	$129,575	$0	$0

Investments_Analysis_of_net_re

Investments - Analysis of net realized gains (losses) and the change in unrealized (losses) gains on investments (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net realized gains (losses):
OTTI on investments, net of amounts transferred to other comprehensive income	($35,700)
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets	107,462	87,777	14,098
Net realized and unrealized (losses) on investment related derivative instruments	20,121	6,367	-1,228
Net realized (losses) on investments and net realized and unrealized (losses) on investment related derivative instruments	127,583	94,144	12,870
Net change in unrealized gains (losses) on investments	970,715	-957,192	1,196,430
Total net realized (losses) on investments, net realized and unrealized (losses) on investment related derivative instruments, and net change in unrealized gains (losses) on investments	1,098,298	-863,048	1,209,300
Fixed maturities \| HTM
Net realized gains (losses):
Net change in unrealized gains (losses) on investments	-272,540	-175,817	221,647
Equity securities
Net realized gains (losses):
Net change in unrealized gains (losses) on investments	-32,577	105,163	44,361
Affiliates and other investments
Net realized gains (losses):
Net change in unrealized gains (losses) on investments	35,143	26,636	46,163
Exclude Life Funds Withheld Assets [Member]
Net realized gains (losses):
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets	122,991	87,777	14,098
Exclude Life Funds Withheld Assets [Member] \| Fixed maturities, short term investments and cash equivalents
Net realized gains (losses):
Gross realized gains	119,817	129,479	163,328
Gross realized losses on investments sold	-66,892	-84,703	-107,033
OTTI on investments, net of amounts transferred to other comprehensive income	-12,341	-16,282	-74,245
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets	40,584	28,494	-17,950
Exclude Life Funds Withheld Assets [Member] \| Fixed maturities \| AFS
Net realized gains (losses):
Net change in unrealized gains (losses) on investments	360,463	-913,174	884,259
Exclude Life Funds Withheld Assets [Member] \| Equity securities
Net realized gains (losses):
Gross realized gains	96,260	29,402	42,009
Gross realized losses on investments sold	-12,270	-3,185	-7,121
OTTI on investments, net of amounts transferred to other comprehensive income	-10,944	-17	-3,746
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets	73,046	26,200	31,142
Exclude Life Funds Withheld Assets [Member] \| Other investments
Net realized gains (losses):
Gross realized gains	31,830	46,934	11,610
Gross realized losses on investments sold	-10,011	-13,851	-7,983
OTTI on investments, net of amounts transferred to other comprehensive income	-12,458	0	-2,721
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets	9,361	33,083	906
Life Funds Withheld Assets [Member]
Net realized gains (losses):
Net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets	-9	0	0
Life Funds Withheld Assets [Member] \| Fixed maturities, short term investments and cash equivalents
Net realized gains (losses):
Gross realized gains	7,926	0	0
Gross realized losses on investments sold	-2,859	0	0
Net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets	-9	0	0
OTTI on investments, net of amounts transferred to other comprehensive income	-20,587	0	0
Total net realized gains (losses) on investments, and net unrealized gains (losses) on investments, Trading - Life Funds Withheld Assets	-15,529	0	0
Life Funds Withheld Assets [Member] \| Fixed maturities \| AFS
Net realized gains (losses):
Net change in unrealized gains (losses) on investments	$880,226	$0	$0

Investments_Credit_loss_impair

Investments - Credit loss impairments on fixed income securities (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
OTTI related to credit losses recognized in earnings
Balance, beginning of period	$174,805	$268,708
Credit loss impairment recognized in the current period on securities not previously impaired	3,907	806
Credit loss impairments previously recognized on securities which matured, paid down, prepaid or were sold during the period	-42,671	-92,167
Credit loss impairments previously recognized on securities impaired to fair value during the period	0	0
Additional credit loss impairments recognized in the current period on securities previously impaired	4,185	11,182
Accretion of credit loss impairments previously recognized due to an increase in cash flows expected to be collected	-8,284	-13,724
Balance, end of period	$131,942	$174,805

Investments_Narrative_Details

Investments - Narrative (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	1-May-14
	positions	Dec. 31, 2013	Dec. 31, 2012	1-May-14
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Fixed maturities, held to maturity, gross unrealized losses	$0
Cumulative adjustments recorded to value of future policy benefit reserves, amount	400,456,000	44,660,000	0
Fixed maturities, AFS, at fair value	29,359,034,000	27,500,136,000
Amortized cost of fixed maturities, available for sale	27,728,771,000	27,111,874,000
Fixed maturities, held to maturity	0	2,858,695,000
Fair value of held to maturity securities	0	3,131,235,000
Percentage of fixed income portfolio invested in securities below investment grade	3.00%	2.60%
Percentage of gross unrealized losses relating to securities below investment grade	24.90%	12.40%
Pledged assets, amount	15,200,000,000	15,500,000,000
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	213,576,000	437,036,000
Total number of positions - AFS	7,669
AFS securities in unrealized loss position (number of positions)	1,631
OTTI on investments, net of amounts transferred to other comprehensive income	35,700,000
Credit loss impairments previously recognized on securities which matured, paid down, prepaid or were sold during the period	42,671,000	92,167,000
Equity securities, AFS, at fair value	868,292,000	1,040,237,000
Cost of equity securities, available for sale	763,833,000	903,201,000
Corporate
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Fixed maturities, held to maturity, gross unrealized gains		113,179,000
Fixed maturities, held to maturity, gross unrealized losses		-968,000
Fixed maturities, AFS, at fair value		11,125,830,000
Amortized cost of fixed maturities, available for sale		10,802,332,000
Fixed maturities, held to maturity		1,386,863,000
Fair value of held to maturity securities		1,499,074,000
OTTI on investments, net of amounts transferred to other comprehensive income	3,700,000
Medium-term Notes [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Fixed maturities, AFS, at fair value	79,900,000	154,600,000
Amortized cost of fixed maturities, available for sale	68,400,000	147,700,000
Fixed Income Funds Member
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Cost of equity securities, available for sale	100,000,000
Structured Credit Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Fair value	5,500,000
Marketable Securities Unrealized Loss Other Than Temporary Impairments Amount	9,600,000
Impaired Investment Cumulative Fair Value Decline Percentage Amortized Cost	50.00%
Other Investments [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
OTTI on investments, net of amounts transferred to other comprehensive income	12,500,000
RMBS - Non-Agency
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Fixed maturities, held to maturity, gross unrealized gains		4,985,000
Fixed maturities, held to maturity, gross unrealized losses		0
Fixed maturities, AFS, at fair value		398,768,000
Amortized cost of fixed maturities, available for sale		396,798,000
Fixed maturities, held to maturity		66,987,000
Fair value of held to maturity securities		71,972,000
OTTI on investments, net of amounts transferred to other comprehensive income	4,300,000
Credit loss impairments previously recognized on securities which matured, paid down, prepaid or were sold during the period	9,000,000	66,100,000
Currency losses
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
OTTI on investments, net of amounts transferred to other comprehensive income	4,200,000
CMBS
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Fixed maturities, held to maturity, gross unrealized gains		11,864,000
Fixed maturities, held to maturity, gross unrealized losses		0
Fixed maturities, AFS, at fair value		1,246,795,000
Amortized cost of fixed maturities, available for sale		1,223,313,000
Fixed maturities, held to maturity		144,924,000
Fair value of held to maturity securities		156,788,000
XL Re Life (SAC) Ltd [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Held To Maturity Securities Transferred Security Carrying Value				2,800,000,000
Fixed maturities, held to maturity, gross unrealized gains				424,900,000
Fixed maturities, held to maturity, gross unrealized losses				0
Unrealized Gains (Losses) on Investments
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Cumulative adjustments recorded to value of future policy benefit reserves, amount	400,456,000
Unrealized Gains (Losses) on Investments \| XL Re Life (SAC) Ltd [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Cumulative adjustments recorded to value of future policy benefit reserves, amount				440,500,000
Exclude Life Funds Withheld Assets [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Fixed maturities, AFS, at fair value	24,177,469,000	27,500,136,000
Amortized cost of fixed maturities, available for sale	23,427,432,000	27,111,874,000
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	213,576,000
Equity securities, AFS, at fair value	868,292,000
Cost of equity securities, available for sale	763,833,000
Exclude Life Funds Withheld Assets [Member] \| Corporate
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Fixed maturities, AFS, at fair value	8,778,373,000
Amortized cost of fixed maturities, available for sale	8,462,130,000
Exclude Life Funds Withheld Assets [Member] \| Equity securities
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
OTTI on investments, net of amounts transferred to other comprehensive income	10,944,000	17,000	3,746,000
Exclude Life Funds Withheld Assets [Member] \| RMBS - Non-Agency
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Fixed maturities, AFS, at fair value	427,351,000
Amortized cost of fixed maturities, available for sale	404,398,000
Exclude Life Funds Withheld Assets [Member] \| CMBS
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Fixed maturities, AFS, at fair value	1,052,544,000
Amortized cost of fixed maturities, available for sale	$1,033,819,000

Investments_in_Affiliates_Deta

Investments in Affiliates (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	$1,637,620		$1,370,943
Investment fund affiliates
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	1,219,138	[1]	1,042,072	[1]
Operating affiliates
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	$418,482		$328,871

[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

Investments_in_Affiliates_Inve

Investments in Affiliates - Investment Fund Affiliates (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]
Carrying value of equity method investments, investment fund affiliates	$1,637,620		$1,370,943
Equity in net income (loss) in operating affiliates	203,034		258,195		112,391
Investment fund affiliates
Schedule of Equity Method Investments [Line Items]
Carrying value of equity method investments, investment fund affiliates	1,219,138	[1]	1,042,072	[1]
Equity in net income (loss) in operating affiliates	95,816	[1]	138,391	[1]
Weighted average XL percentage ownership	6.40%	[1]	5.30%	[1]
Combined funds/ estimated total net assets	19,177,932	[1],[2]	19,766,826	[1],[2]
Investment fund affiliates \| Alternative funds
Schedule of Equity Method Investments [Line Items]
Carrying value of equity method investments, investment fund affiliates	1,023,160	[1]	867,502	[1]
Equity in net income (loss) in operating affiliates	67,037	[1]	108,449	[1]
Weighted average XL percentage ownership	5.70%	[1]	4.60%	[1]
Combined funds/ estimated total net assets	18,072,156	[1],[2]	18,876,011	[1],[2]
Investment fund affiliates \| Arbitrage
Schedule of Equity Method Investments [Line Items]
Carrying value of equity method investments, investment fund affiliates	134,400	[1]	158,096	[1]
Equity in net income (loss) in operating affiliates	12,060	[1]	4,358	[1]
Weighted average XL percentage ownership	11.00%	[1]	3.70%	[1]
Combined funds/ estimated total net assets	1,224,526	[1],[2]	4,328,748	[1],[2]
Investment fund affiliates \| Directional
Schedule of Equity Method Investments [Line Items]
Carrying value of equity method investments, investment fund affiliates	536,470	[1]	434,652	[1]
Equity in net income (loss) in operating affiliates	32,196	[1]	42,492	[1]
Weighted average XL percentage ownership	9.20%	[1]	8.30%	[1]
Combined funds/ estimated total net assets	5,865,247	[1],[2]	5,235,690	[1],[2]
Investment fund affiliates \| Event driven
Schedule of Equity Method Investments [Line Items]
Carrying value of equity method investments, investment fund affiliates	300,168	[1],[3]	274,380	[1],[3]
Equity in net income (loss) in operating affiliates	21,030	[1],[3]	61,551	[1],[3]
Weighted average XL percentage ownership	3.10%	[1],[3]	2.90%	[1],[3]
Combined funds/ estimated total net assets	9,703,973	[1],[2],[3]	9,309,163	[1],[2],[3]
Investment fund affiliates \| Multi-style
Schedule of Equity Method Investments [Line Items]
Carrying value of equity method investments, investment fund affiliates	52,122	[1]	374	[1]
Equity in net income (loss) in operating affiliates	1,751	[1]	48	[1]
Weighted average XL percentage ownership	4.10%	[1]	15.50%	[1]
Combined funds/ estimated total net assets	1,278,410	[1],[2]	2,410	[1],[2]
Investment fund affiliates \| Private investment funds
Schedule of Equity Method Investments [Line Items]
Carrying value of equity method investments, investment fund affiliates	195,978	[1]	174,570	[1]
Equity in net income (loss) in operating affiliates	28,779	[1]	29,942	[1]
Weighted average XL percentage ownership	17.70%	[1]	19.60%	[1]
Combined funds/ estimated total net assets	$1,105,776	[1],[2]	$890,815	[1],[2]

[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 for alternative fund affiliates and September 30 for private investment fund affiliates.
[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.

Investments_in_Affiliates_Oper

Investments in Affiliates - Operating Affiliates (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	$1,637,620		$1,370,943
Equity in net income (loss) in operating affiliates	203,034		258,195		112,391
Operating affiliates
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	418,482		328,871
Equity in net income (loss) in operating affiliates	107,218		119,804
Investee summarized data - total assets	5,530,061	[1]	3,569,335
Investee summarized data - total liabilities	3,792,261	[1]	1,981,453
Investee summarized data - total revenue (loss)	1,655,459	[1]	1,716,109
Investee summarized data - net income (loss)	628,963	[1]	836,037
Other strategic operating affiliates
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	317,216		266,796
Equity in net income (loss) in operating affiliates	50,132		41,160
Investee summarized data - total assets	4,679,395	[1]	2,646,987	[1]
Investee summarized data - total liabilities	3,691,173	[1]	1,888,879	[1]
Investee summarized data - total revenue (loss)	1,075,935	[1]	902,522	[1]
Investee summarized data - net income (loss)	152,122	[1]	125,625	[1]
Investment manager affiliates
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	101,266		62,075	[2]
Equity in net income (loss) in operating affiliates	57,086		78,644	[2]
Investee summarized data - total assets	850,666	[1]	922,348	[1],[2]
Investee summarized data - total liabilities	101,088	[1]	92,574	[1],[2]
Investee summarized data - total revenue (loss)	579,524	[1]	813,587	[1],[2]
Investee summarized data - net income (loss)	$476,841	[1]	$710,412	[1],[2]

[1]	The Company generally records its operating affiliates on a three-month lag. Estimated assets and liabilities are generally at September 30, 2014 and 2013, respectively.
[2]	During the years ended December 31, 2014 and 2013, the Company received distributions from its Investment Manager Affiliates of approximately $60.3 million and $28.3 million, respectively.

Investments_in_Affiliates_Inve1

Investments in Affiliates - Investment Fund Consolidation (Details) (USD $)	12 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2011	31-May-12
Investment Fund Consolidation [Line Items]
Fixed maturities, AFS, at fair value	$27,500,136,000		$29,359,034,000
Amortized cost of fixed maturities, available for sale	27,111,874,000		27,728,771,000
Asset derivative fair value	26,145,000		135,963,000
Cash and cash equivalents	1,800,832,000		2,521,814,000	2,618,378,000	3,825,125,000
Other liabilities	950,845,000		912,748,000
Non-controlling interest in equity of consolidated subsidiaries	1,351,665,000		1,402,015,000
Cost of operating affiliate interests acquired	30,000,000
Five Oaks Investment Corp [Member]
Investment Fund Consolidation [Line Items]
Investment amount						25,000,000
Percentage ownership						94.00%
Sale of Stock, Percentage of Ownership after Transaction		43.80%
Deconsolidation, Gain (Loss), Amount		1,500,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			3,125,000
Class of Warrant or Right, Exercise Price of Warrants or Rights			$15.75
Cost of operating affiliate interests acquired			49,200,000
Ownership percentage remaining			21.90%
Five Oaks Investment Corp [Member] \| IPO [Member]
Investment Fund Consolidation [Line Items]
Sale of Stock, Number of Shares Issued in Transaction		4,000,000
Sale of Stock, Consideration Received Per Transaction		61,000,000
Five Oaks Investment Corp [Member] \| Private Placement [Member]
Investment Fund Consolidation [Line Items]
Sale of Stock, Number of Shares Issued in Transaction		1,670,000
Sale of Stock, Consideration Received Per Transaction		$25,000,000
Five Oaks Investment Corp [Member] \| Received in Distribution [Member]
Investment Fund Consolidation [Line Items]
Sale of Stock, Number of Shares Issued in Transaction		8,175

Investments_in_Affiliates_Narr

Investments in Affiliates - Narrative (Details) (USD $)	12 Months Ended
Investments in Affiliates - Narrative (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	$1,637,620,000	$1,370,943,000
Number of interests in operating affiliates purchased		1
Cost of operating affiliate interests acquired		30,000,000
Operating affiliates
Schedule of Equity Method Investments [Line Items]
Alternative investments, timelag for reporting	3 months
Investments in affiliates	418,482,000	328,871,000
Other strategic operating affiliates
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	317,216,000	266,796,000
ARX Holding Corporation [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage remaining	40.00%
Investment manager affiliates
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	101,266,000	62,075,000	[1]
Distributions received from investment manager affiliates	60,300,000	28,300,000
Subject To Redemption Restrictions [Member]
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	543,000,000	488,500,000
Funds held in side pockets
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	$22,200,000	$42,300,000
Investments in the common stock of a corporation
Schedule of Equity Method Investments [Line Items]
Threshold for signicant influence, percentage	20.00%
Investments in closed end funds, limited partnerships, LLCs or similar investment vehicles
Schedule of Equity Method Investments [Line Items]
Threshold for signicant influence, percentage	3.00%
Alternative funds
Schedule of Equity Method Investments [Line Items]
Alternative investments, timelag for reporting	1 month
Private investment funds
Schedule of Equity Method Investments [Line Items]
Alternative investments, timelag for reporting	3 months

[1]	During the years ended December 31, 2014 and 2013, the Company received distributions from its Investment Manager Affiliates of approximately $60.3 million and $28.3 million, respectively.

Other_Investments_Components_o

Other Investments - Components of other investments (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Other Investments [Line Items]
Other investments	$1,248,439	$1,164,630
Alternative funds
Other Investments [Line Items]
Other investments	640,847	645,187
Arbitrage
Other Investments [Line Items]
Other investments	179,821	158,220
Directional
Other Investments [Line Items]
Other investments	336,082	357,469
Event driven
Other Investments [Line Items]
Other investments	56,238	56,873
Multi-style
Other Investments [Line Items]
Other investments	68,706	72,625
Private investment funds
Other Investments [Line Items]
Other investments	129,243	94,064
Overseas deposits
Other Investments [Line Items]
Other investments	92,223	111,302
Structured transactions
Other Investments [Line Items]
Other investments	350,563	294,048
Other
Other Investments [Line Items]
Other investments	$35,563	$20,029

Other_Investments_Analysis_of_

Other Investments - Analysis of net realized and unrealized gains on other investments (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other Investments [Line Items]
Net unrealized gains (losses)	$231,278	$202,852
Net realized gains (losses)	19,960	35,189	-1,896
Alternative funds
Other Investments [Line Items]
Net unrealized gains (losses)	188,674	158,825
Net realized gains (losses)	6,685	30,858	-2,153
Private investment funds
Other Investments [Line Items]
Net unrealized gains (losses)	42,604	44,027
Net realized gains (losses)	$13,275	$4,331	$257

Other_Investments_Narrative_De

Other Investments - Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
	funds	strategy
	strategy	funds
Other Investments [Line Items]
Number of strategies employed	4	4
Number of funds invested in	16	16
Required notice period for redemption	30 days
Other investments	$1,248,439,000	$1,164,630,000
Project Finance Loans:
Aggregate loan value	400,000	15,200,000
Aggregate loan net carrying amount	0	11,100,000
Aggregate principal amount of payment obligation purchased	150,000,000
Estimated fair value of payment obligation at date of purchase	128,100,000
Coupon rate on outstanding payment obligation	3.50%
Term of payment obligation	11 years 6 months
Fair value of difference between estimated fair value and cost of payment obligation	21,900,000
Payment obligation, fees	2,500,000
Other than temporary declines recorded on other investments during the period	12,500,000
Alternative funds \| Funds which are subject to lockups and/or gate provisions
Other Investments [Line Items]
Other investments	425,700,000	360,600,000
Alternative funds \| Funds held in side pockets
Other Investments [Line Items]
Other investments	24,500,000	24,100,000
Alternative funds \| Funds held in side pockets \| Minimum
Other Investments [Line Items]
Side pockets - liquidation period of underlying investments	2 years
Alternative funds \| Funds held in side pockets \| Maximum
Other Investments [Line Items]
Side pockets - liquidation period of underlying investments	4 years
Cypress Point 1 [Member]
Project Finance Loans:
Aggregate face amount of structured transactions purchased	155,000,000
Carrying amount of structured finance transaction entered into by XLIB	136,000,000	148,000,000
Cypress Point 2 [Member]
Project Finance Loans:
Aggregate face amount of structured transactions purchased	81,900,000
Carrying amount of structured finance transaction entered into by XLIB	$77,800,000

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, beginning of year	$396,245	$392,882	$391,498
Additions	25,159
Foreign currency translation	-5,468	3,363	1,384
Goodwill, end of year	415,936	396,245	392,882
Intangible assets with an indefinite life, beginning of year	15,366	15,366	15,366
Intangible assets with an indefinite life, end of year	15,366	15,366	15,366
Intangible assets with a definite life, beginning of year	0	279	457
Additions	18,500
Amortization	-1,850	-279	-178
Intangible assets with a definite life, end of year	16,650	0	279
Goodwill and other intangible assets, beginning of year	411,611	408,527	407,321
Additions	43,659
Goodwill and other intangible assets, end of year	$447,952	$411,611	$408,527

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets - Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$415,936,000	$396,245,000	$392,882,000	$391,498,000
Gross goodwill	1,800,000,000	1,800,000,000
Accumulated impairment loss on goodwill	$1,400,000,000	$1,400,000,000
Estimated performance period	10 years

Reinsurance_Effects_of_Reinsur

Reinsurance - Effects of Reinsurance (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net premiums written:
Net premiums written	$5,944,841	$6,199,404	$6,281,451
Net premiums earned:
Direct premiums earned	5,173,403	4,966,207	4,604,323
Assumed premiums earned	2,676,765	2,687,603	2,749,271
Ceded premiums earned	-1,955,098	-1,344,289	-1,263,157
Net amount, premiums earned	5,895,070	6,309,521	6,090,437
Total P And C Segment [Member]
Net premiums written:
Direct premiums written	5,450,868	5,050,953	4,733,516
Assumed premiums written	2,310,621	2,365,839	2,441,612
Ceded premiums written	-1,994,280	-1,512,810	-1,218,109
Net premiums written	5,767,209	5,903,982	5,957,019
Net premiums earned:
Direct premiums earned	5,173,403	4,966,207	4,604,323
Assumed premiums earned	2,343,329	2,363,261	2,393,490
Ceded premiums earned	-1,799,294	-1,315,369	-1,231,835
Net amount, premiums earned	$5,717,438	$6,014,099	$5,765,978

Reinsurance_Components_of_Unpa

Reinsurance - Components of Unpaid Losses and Loss Expenses Recoverable (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Analysis of total unpaid losses and loss expenses recoverable by segment:
Unpaid losses and loss expenses recoverable	$3,429,368	$3,435,230
Total P And C Segment [Member]
Analysis of total unpaid losses and loss expenses recoverable by segment:
Unpaid losses and loss expenses recoverable	3,411,526	3,414,735
Corporate and other
Analysis of total unpaid losses and loss expenses recoverable by segment:
Unpaid losses and loss expenses recoverable	$17,842	$20,495

Reinsurance_Ceded_Credit_Risk_

Reinsurance - Ceded Credit Risk (Details)	Dec. 31, 2014	Dec. 31, 2013
Ceded Credit Risk [Line Items]
Percentage of total reinsurance recoverables	100.00%
AAA
Ceded Credit Risk [Line Items]
Percentage of total reinsurance recoverables	0.10%
AA
Ceded Credit Risk [Line Items]
Percentage of total reinsurance recoverables	42.00%
A
Ceded Credit Risk [Line Items]
Percentage of total reinsurance recoverables	50.40%
BBB
Ceded Credit Risk [Line Items]
Percentage of total reinsurance recoverables	0.40%
Captives
Ceded Credit Risk [Line Items]
Percentage of total reinsurance recoverables	5.40%
Other
Ceded Credit Risk [Line Items]
Percentage of total reinsurance recoverables	1.70%
A- or better rating
Ceded Credit Risk [Line Items]
Percentage of total reinsurance recoverables	93.00%	90.00%
Ceded Credit Risk, Concentrated Credit Risk [Member]
Ceded Credit Risk [Line Items]
Threshold percentage, concentration risk	3.00%
Ceded Credit Risk, Concentrated Credit Risk [Member] \| AA- \| Munich Reinsurance Company
Ceded Credit Risk [Line Items]
Percentage of total reinsurance recoverables	10.50%
Ceded Credit Risk, Concentrated Credit Risk [Member] \| AA- \| Swiss Reinsurance Company
Ceded Credit Risk [Line Items]
Percentage of total reinsurance recoverables	8.80%
Ceded Credit Risk, Concentrated Credit Risk [Member] \| AA- \| Swiss Re Europe S.A.
Ceded Credit Risk [Line Items]
Percentage of total reinsurance recoverables	7.70%
Ceded Credit Risk, Concentrated Credit Risk [Member] \| AA- \| Arch Reinsurance Co [Member]
Ceded Credit Risk [Line Items]
Percentage of total reinsurance recoverables	6.30%
Ceded Credit Risk, Concentrated Credit Risk [Member] \| AA- \| LLoyds Syndicate [Member]
Ceded Credit Risk [Line Items]
Percentage of total reinsurance recoverables	5.10%
Ceded Credit Risk, Concentrated Credit Risk [Member] \| A+ \| Transatlantic Reinsurance Company [Member]
Ceded Credit Risk [Line Items]
Percentage of total reinsurance recoverables	8.10%
Ceded Credit Risk, Concentrated Credit Risk [Member] \| A+ \| Axis Reinsurance Co [Member]
Ceded Credit Risk [Line Items]
Percentage of total reinsurance recoverables	4.60%

Reinsurance_Narrative_Details

Reinsurance - Narrative (Details) (USD $)	12 Months Ended
Reinsurance - Narrative (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reinsurance Disclosures [Abstract]
Reinsurance recoveries on losses and loss expenses recorded during period	$700,000,000	$700,000,000	$600,000,000
Total reinsurance assets	3,600,000,000	3,600,000,000
Reinsurance receivable on paid losses	131,519,000	118,885,000
Unpaid losses and loss expenses recoverable	3,429,368,000	3,435,230,000
Total allowance for uncollectible reinsurance	64,439,000	85,532,000
Collateral held related to reinsurance recoverables	2,000,000,000	1,800,000,000
Total allowance recorded relating to reinsurance recoverables	42,300,000	41,400,000
Total allowance recorded relating to reinsurance balances receivable	$22,100,000	$44,200,000

Losses_and_Loss_Expenses_Compo

Losses and Loss Expenses - Components of Loss Reserves (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Liability for Claims and Claims Adjustment Expense [Abstract]
Reserve for reported losses and loss expenses	$7,461,444	$8,149,501
Reserve for losses incurred but not reported	11,891,799	12,331,564
Unpaid losses and loss expenses at end of year	$19,353,243	$20,481,065	$20,484,121	$20,613,901

Losses_and_Loss_Expenses_Loss_

Losses and Loss Expenses - Loss Reserve Rollforward and Components of Net Losses and Loss Expenses (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Components of Net Losses And Loss Expenses Incurred [Abstract]
Net losses and loss expenses incurred	$3,258,393	$3,731,464	$3,765,482
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Unpaid losses and loss expenses at beginning of year	20,481,065	20,484,121	20,613,901
Unpaid losses and loss expenses recoverable at beginning of year	3,414,735	3,361,703	3,629,940
Net unpaid losses and loss expenses at beginning of year	17,066,330	17,122,418	16,983,961
Increase (decrease) in net losses and loss expenses incurred in respect of losses occurring in:
Current year	3,513,469	4,021,353	4,081,376
Prior year development	-255,076	-289,889	-315,894
Total net incurred losses and loss expenses	3,258,393	3,731,464	3,765,482
Exchange rate effects	-561,673	40,587	156,217
Less net losses and loss expenses paid in respect of losses occurring in:
Current year	381,008	425,254	416,844
Prior years	3,440,327	3,402,885	3,366,398
Total net paid losses	3,821,335	3,828,139	3,783,242
Net unpaid losses and loss expenses at end of year	15,941,715	17,066,330	17,122,418
Unpaid losses and loss expenses recoverable at end of year	3,411,528	3,414,735	3,361,703
Unpaid losses and loss expenses at end of year	19,353,243	20,481,065	20,484,121
Loss and loss expenses payments
Components of Net Losses And Loss Expenses Incurred [Abstract]
Net losses and loss expenses incurred	4,499,642	4,496,802	4,673,998
Change in unpaid losses and loss expenses
Components of Net Losses And Loss Expenses Incurred [Abstract]
Net losses and loss expenses incurred	-514,406	-71,901	-297,660
Change in unpaid losses and loss expenses recoverable
Components of Net Losses And Loss Expenses Incurred [Abstract]
Net losses and loss expenses incurred	-48,536	-24,774	279,900
Paid loss recoveries
Components of Net Losses And Loss Expenses Incurred [Abstract]
Net losses and loss expenses incurred	($678,307)	($668,663)	($890,756)

Losses_and_Loss_Expenses_Prior

Losses and Loss Expenses - Prior Year Development - Summary (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	($255,076)	($289,889)	($315,894)
Insurance Segment [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-99,762	-102,039	-140,066
Insurance Segment [Member] \| Property
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-57,470	-46,387	-46,735
Insurance Segment [Member] \| Casualty
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	38,413	-21,829	-61,630
Insurance Segment [Member] \| Professional
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	17,094	75,045	-106,360
Insurance Segment [Member] \| Specialty
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-82,756	-140,740	-61,755
Insurance Segment [Member] \| Other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-15,043	31,872	136,414
Reinsurance Segment [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-155,314	-187,850	-175,828
Reinsurance Segment [Member] \| Casualty
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-44,300	-72,200	-60,300
Reinsurance Segment [Member] \| Other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-25,700	21,300	-7,900
Reinsurance Segment [Member] \| Property and other short-tail lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-85,324	-136,912	-107,613
Reinsurance Segment [Member] \| Casualty and other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	($69,990)	($50,938)	($68,215)

Losses_and_Loss_Expenses_Prior1

Losses and Loss Expenses - Prior Year Development - Insurance (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	($255,076)	($289,889)	($315,894)
Insurance Segment [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-99,762	-102,039	-140,066
Insurance Segment [Member] \| Property
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-57,470	-46,387	-46,735
Insurance Segment [Member] \| Property \| 2011 Accident Year [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-21,100
Insurance Segment [Member] \| Casualty
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	38,413	-21,829	-61,630
Insurance Segment [Member] \| Excess Casualty [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-28,600
Insurance Segment [Member] \| Environmental Lines [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	34,900
Insurance Segment [Member] \| Lloyds Middle Market [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	33,300
Insurance Segment [Member] \| Professional Lines [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	17,094	75,045	-106,360
Insurance Segment [Member] \| Professional Lines [Member] \| Clash losses
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development			-120,800
Insurance Segment [Member] \| Specialty
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-82,756	-140,740	-61,755
Insurance Segment [Member] \| Aerospace [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-61,900
Insurance Segment [Member] \| Marine Lines [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-5,600
Insurance Segment [Member] \| Other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-15,043	31,872	136,414
Insurance Segment [Member] \| United States \| Casualty
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	26,400
Insurance Segment [Member] \| United States \| Professional Lines [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	40,900
Insurance Segment [Member] \| Bermuda \| Professional Lines [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-21,800
Insurance Segment [Member] \| International [Member] \| Casualty
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-28,100
Insurance Segment [Member] \| International [Member] \| Specialty
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	($12,200)

Losses_and_Loss_Expenses_Prior2

Losses and Loss Expenses - Prior Year Development - Reinsurance (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	($255,076)	($289,889)	($315,894)
Reinsurance Segment [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-155,314	-187,850	-175,828
Reinsurance Segment [Member] \| Property and other short-tail lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-85,324	-136,912	-107,613
Reinsurance Segment [Member] \| Property catastrophe lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	12,400	-60,000	-16,500
Reinsurance Segment [Member] \| Property other lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-63,400	-57,300	-49,000
Reinsurance Segment [Member] \| Marine and aviation lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-34,400	-19,600	-42,200
Reinsurance Segment [Member] \| Marine and aviation lines \| Release on attritional losses
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-37,700
Reinsurance Segment [Member] \| Marine and aviation lines \| Major catastrophe
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	3,300
Reinsurance Segment [Member] \| Casualty and other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-69,990	-50,938	-68,215
Reinsurance Segment [Member] \| Casualty
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-44,300	-72,200	-60,300
Reinsurance Segment [Member] \| Other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-25,700	21,300	-7,900
Reinsurance Segment [Member] \| Other \| Release on attritional losses
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-22,700
Reinsurance Segment [Member] \| Other \| Major catastrophe
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development	-3,000
Reinsurance Segment [Member] \| Other \| Structured Indemnity
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development			($8,400)

Losses_and_Loss_Expenses_Loss_1

Losses and Loss Expenses - Loss Reserve Discounting (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Loss And Loss Expenses Disclosure [Line Items]
Unpaid losses and loss expenses	$19,353,243,000	$20,481,065,000	$20,484,121,000	$20,613,901,000
Workers' compensation
Loss And Loss Expenses Disclosure [Line Items]
Discount rate used on unpaid losses for workers compensation	5.00%	5.00%
Unpaid losses and loss expenses	566,200,000	609,100,000
Undiscounted tabular unpaid losses and loss expenses, net of reinsurance reserve	515,400,000	551,600,000
Tabular unpaid losses and loss expenses	266,400,000	274,600,000
UK motor liabilities
Loss And Loss Expenses Disclosure [Line Items]
Discount rate used on unpaid losses	1.50%	1.50%
Undiscounted tabular unpaid losses and loss expenses, net of reinsurance reserve	249,800,000	262,000,000
Tabular unpaid losses and loss expenses	$161,000,000	$165,700,000

Losses_and_Loss_Expenses_Asbes

Losses and Loss Expenses - Asbestos and Environmental Exposures (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of opening and closing unpaid losses and loss expenses related to asbestos and environmental exposure claims:
Net unpaid losses and loss expenses at beginning of year	$80,435,000	$78,315,000	$77,778,000
Net incurred losses and loss expenses	8,903,000	6,257,000	6,558,000
Less net paid losses and loss expenses	7,922,000	4,137,000	6,021,000
Net increase (decrease) in unpaid losses and loss expenses	981,000	2,120,000	537,000
Net unpaid losses and loss expenses at end of year	81,416,000	80,435,000	78,315,000
Unpaid losses and loss expenses recoverable at end of year	100,537,000	115,090,000	123,799,000
Gross unpaid losses and loss expenses at end of year	181,953,000	195,525,000	202,114,000
Reserves for incurred but not reported losses, net of reinsurance	$49,300,000	$48,600,000	$52,200,000

Losses_and_Loss_Expenses_Asbes1

Losses and Loss Expenses - Asbestos and Environmental Exposures Claims Rollforward (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	claims	claims	claims
Asbestos claims
Reconciliation of opening and closing unpaid losses and loss expenses related to asbestos and environmental exposure claims:
Total number of claims outstanding, beginning of period	1,097	1,073	1,038
New claims reported	456	178	236
Claims resolved	-154	-154	-201
Total number of claims outstanding, end of period	1,399	1,097	1,073
Environmental claims
Reconciliation of opening and closing unpaid losses and loss expenses related to asbestos and environmental exposure claims:
Total number of claims outstanding, beginning of period	338	354	362
New claims reported	190	34	60
Claims resolved	-69	-50	-68
Total number of claims outstanding, end of period	459	338	354

Losses_and_Loss_Expenses_Asbes2

Losses and Loss Expenses - Asbestos and Environmental Exposures Discussion (Details) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2006	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	Dec. 31, 2006	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	claims
Loss And Loss Expenses Disclosure [Line Items]
Losses acquired through portfolio transfer, amount	$40.20
Combined aggregate limit on reserves acquired	60
Reserves for incurred but not reported losses, net of reinsurance		49.3	48.6	52.2
Net asbestos and environmental reserves to total reserves, percentage		1.00%	1.00%
Asbestos and environmental claims
Loss And Loss Expenses Disclosure [Line Items]
Losses acquired through portfolio transfer, amount	$18.30
Claim files due to precautionary claim notices, percentage		46.00%	37.00%	42.00%
Environmental claims
Loss And Loss Expenses Disclosure [Line Items]
Total number of claims outstanding		459	338	354	362
Asbestos claims
Loss And Loss Expenses Disclosure [Line Items]
Total number of claims outstanding		1,399	1,097	1,073	1,038

Deposit_Liabilities_Details

Deposit Liabilities (Details) (USD $)	12 Months Ended
Deposit Liabilities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net results from structured products	$54,209,000	$23,791,000	$5,257,000
Deposit liabilities	1,245,367,000	1,509,243,000
Accretion expense on deposit liabilities	12,900,000	48,000,000	66,300,000
Interest Expense [Member] \| Total P And C Segment [Member]
Net results from structured products	-12,900,000	-48,000,000	-66,300,000
Interest Expense [Member] \| Total P And C Segment [Member] \| Structured Indemnity
Net results from structured products	$28,700,000

Future_Policy_Benefit_Reserve_1

Future Policy Benefit Reserve (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	30-May-14
Future policy benefit reserves are comprised of the following:
Traditional life	$789,133	$827,341
Annuities	3,918,066	3,976,475
Total future policy benefit reserves	4,707,199	4,803,816
Other information:
Average interest rate used for future policy benefits, percent	3.30%	4.40%
XL Re Life (SAC) Ltd [Member]
Liability for Future Policy Benefit, by Product Segment [Line Items]
Future Policy Benefit Reserves Recoverable	$4,265,678		$4,800,000

Funds_Withheld_on_Life_Retroce2

Funds Withheld on Life Retrocession Arrangements (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	30-May-14
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	30-May-14
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable: 2014, $4,265,678; 2013, nil)	$1,155,016	$0
XL Re Life (SAC) Ltd [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held on a funds withheld basis relating to the Life Retro Arrangements	5,420,694
Reinsurance recoverable from GCLR	-4,265,678		-4,800,000
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable: 2014, $4,265,678; 2013, nil)	$1,155,016

Notes_Payable_and_Debt_and_Fin2

Notes Payable and Debt and Financing Arrangements - Financing Structure (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Sep. 15, 2014
Debt Instrument [Line Items]
Total commitment available	$2,675,000		$3,275,000
Total debt outstanding before fair value hedge	1,662,580	[1]	2,260,436	[1]
Adjustment to carrying value - impact of fair value hedges	0	[1]	2,767	[1]
Notes payable and debt	1,662,580		2,263,203
Percentage Ownership Of Subsidiaries	100.00%		100.00%
Letter of credit facility
Debt Instrument [Line Items]
Available letter of credit facilities - commitments	3,575,000	[2],[3]	3,575,000	[2],[3]
Available letter of credit facilities - in use	1,790,561	[1],[2]	1,895,425	[1],[2]
Revolving credit facility
Debt Instrument [Line Items]
Available letter of credit facilities - commitments	1,000,000	[2],[4]	1,000,000	[2],[4]
Available letter of credit facilities - in use	0	[1]	0	[1]
Term of credit facility	5 years
Senior notes
Debt Instrument [Line Items]
Debt instrument interest rate, stated percentage					5.25%
Senior notes \| 5.25% Senior Notes due 2014
Debt Instrument [Line Items]
Debt instrument face amount	0		600,000
Total debt outstanding before fair value hedge	0	[1]	599,346	[1]
Debt instrument interest rate, stated percentage	5.25%
Senior notes \| 2.3% Senior Notes due 2018
Debt Instrument [Line Items]
Debt instrument face amount	300,000		300,000
Total debt outstanding before fair value hedge	297,344	[1]	296,683	[1]
Debt instrument interest rate, stated percentage	2.30%
Senior notes \| 5.75% Senior Notes due 2021
Debt Instrument [Line Items]
Debt instrument face amount	400,000		400,000
Total debt outstanding before fair value hedge	397,092	[1]	396,661	[1]
Debt instrument interest rate, stated percentage	5.75%
Senior notes \| 6.375% Senior Notes due 2024
Debt Instrument [Line Items]
Debt instrument face amount	350,000		350,000
Total debt outstanding before fair value hedge	348,920	[1]	348,811	[1]
Debt instrument interest rate, stated percentage	6.38%
Senior notes \| 6.25% Senior Notes due 2027
Debt Instrument [Line Items]
Debt instrument face amount	325,000		325,000
Total debt outstanding before fair value hedge	323,062	[1]	322,905	[1]
Debt instrument interest rate, stated percentage	6.25%
Senior notes \| 5.25% Senior Notes due 2043
Debt Instrument [Line Items]
Debt instrument face amount	300,000		300,000
Total debt outstanding before fair value hedge	$296,162	[1]	$296,030	[1]
Debt instrument interest rate, stated percentage	5.25%

[1]	bIn Useb and bOutstandingb data represent December 31, 2014 and 2013 accreted values.
[2]	At December 31, 2014, there were eight available letter of credit facilities; at December 31, 2013, there were seven available letter of credit facilities.
[3]	The Company has the option to increase the size of the facilities under the Syndicated Credit Agreements by an additional $500 million across such facilities. The Company also has the option to increase the maximum amount of the letters of credit and revolving credit loans available under the 2013 Citi Agreements, with the lender's and issuing lender's consent.
[4]	At December 31, 2014 and 2013, the revolving credit available under the Syndicated Credit Agreements (as defined below) and under the December 9, 2011 unsecured credit agreement, respectively, was unutilized. The 2013 Citi Agreements (as defined below) provide for issuance of letters of credit and revolving credit loans in an aggregate amount of up to $575 million. At December 31, 2014, $575 million of letters of credit were issued under the 2013 Citi Agreements and therefore such amount is not included here.

Notes_Payable_and_Debt_and_Fin3

Notes Payable and Debt and Financing Arrangements - Letter of credit summary (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 30, 2014
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 30, 2014
Letter of credit facility
Line of Credit Facility [Line Items]
Available letter of credit facilities - commitments	$3,575,000	[1],[2]	$3,575,000	[1],[2]
Available letter of credit facilities - in use	1,790,561	[1],[3]	1,895,425	[1],[3]
Collateralized by certain assets of the Company's investment portfolio	66.20%	[1]	67.60%	[1]
Revolving credit facility
Line of Credit Facility [Line Items]
Available letter of credit facilities - commitments	1,000,000	[1],[4]	1,000,000	[1],[4]
Available letter of credit facilities - in use	0	[3]	0	[3]
ING Bank N.V., London Branch [Member] \| Letter of credit facility
Line of Credit Facility [Line Items]
Available letter of credit facilities - in use	150,000
Citibank Europe plc [Member] \| Letter of credit facility
Line of Credit Facility [Line Items]
Available letter of credit facilities - in use	$600,000				$750,000

[1]	At December 31, 2014, there were eight available letter of credit facilities; at December 31, 2013, there were seven available letter of credit facilities.
[2]	The Company has the option to increase the size of the facilities under the Syndicated Credit Agreements by an additional $500 million across such facilities. The Company also has the option to increase the maximum amount of the letters of credit and revolving credit loans available under the 2013 Citi Agreements, with the lender's and issuing lender's consent.
[3]	bIn Useb and bOutstandingb data represent December 31, 2014 and 2013 accreted values.
[4]	At December 31, 2014 and 2013, the revolving credit available under the Syndicated Credit Agreements (as defined below) and under the December 9, 2011 unsecured credit agreement, respectively, was unutilized. The 2013 Citi Agreements (as defined below) provide for issuance of letters of credit and revolving credit loans in an aggregate amount of up to $575 million. At December 31, 2014, $575 million of letters of credit were issued under the 2013 Citi Agreements and therefore such amount is not included here.

Notes_Payable_and_Debt_and_Fin4

Notes Payable and Debt and Financing Arrangements - Narrative relating to credit facilities (Details) (USD $)	1 Months Ended	0 Months Ended
	Nov. 30, 2013	Sep. 15, 2014	Dec. 31, 2014		Dec. 31, 2013
	Credit_Facilities	Sep. 15, 2014	Credit_Facilities		Credit_Facilities
Line of Credit Facility [Line Items]
Number of letter of credit facilities available			8		7
Syndicated Credit Agreements
Line of Credit Facility [Line Items]
Available letter of credit facilities - commitments	$2,000,000,000
Optional increase capacity			500,000,000
Number of credit facilities entered into	2
2013 secured credit agreement
Line of Credit Facility [Line Items]
Available letter of credit facilities - commitments			1,000,000,000
2013 unsecured credit agreement
Line of Credit Facility [Line Items]
Available letter of credit facilities - commitments			1,000,000,000
2013 Citi Agreements
Line of Credit Facility [Line Items]
Available letter of credit facilities - commitments			575,000,000
2011 credit agreements
Line of Credit Facility [Line Items]
Terminated credit capacity	3,000,000,000
Revolving credit facility
Line of Credit Facility [Line Items]
Available letter of credit facilities - in use			0	[1]	0	[1]
Available letter of credit facilities - commitments			1,000,000,000	[2],[3]	1,000,000,000	[2],[3]
Revolving credit facility \| 2013 Citi Agreements
Line of Credit Facility [Line Items]
Available letter of credit facilities - commitments			575,000,000
Letter of credit facility
Line of Credit Facility [Line Items]
Available letter of credit facilities - in use			1,790,561,000	[1],[2]	1,895,425,000	[1],[2]
Available letter of credit facilities - commitments			3,575,000,000	[2],[4]	3,575,000,000	[2],[4]
Letter of credit facility \| 2013 Citi Agreements
Line of Credit Facility [Line Items]
Available letter of credit facilities - in use			575,000,000
Senior notes
Line of Credit Facility [Line Items]
Extinguishment of Debt, Amount		$600,000,000
Debt instrument interest rate, stated percentage		5.25%

[1]	bIn Useb and bOutstandingb data represent December 31, 2014 and 2013 accreted values.
[2]	At December 31, 2014, there were eight available letter of credit facilities; at December 31, 2013, there were seven available letter of credit facilities.
[3]	At December 31, 2014 and 2013, the revolving credit available under the Syndicated Credit Agreements (as defined below) and under the December 9, 2011 unsecured credit agreement, respectively, was unutilized. The 2013 Citi Agreements (as defined below) provide for issuance of letters of credit and revolving credit loans in an aggregate amount of up to $575 million. At December 31, 2014, $575 million of letters of credit were issued under the 2013 Citi Agreements and therefore such amount is not included here.
[4]	The Company has the option to increase the size of the facilities under the Syndicated Credit Agreements by an additional $500 million across such facilities. The Company also has the option to increase the maximum amount of the letters of credit and revolving credit loans available under the 2013 Citi Agreements, with the lender's and issuing lender's consent.

Derivative_Instruments_Gross_a

Derivative Instruments - Gross amounts of derivative fair values contained in the consolidated balance sheet (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Derivatives Fair Value [Line Items]
Asset derivative fair value	$136,659		$27,487
Liability derivative fair value	31,184		105,485
Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Asset derivative notional amount	2,300,609		1,005,610
Asset derivative fair value	121,862	[1]	26,098	[1]
Liability derivative notional amount	302,211		2,572,227
Liability derivative fair value	2,936	[1]	70,462	[1]
Designated as Hedging Instrument \| Foreign Exchange Contract
Derivatives Fair Value [Line Items]
Asset derivative notional amount	2,300,609		1,005,610
Asset derivative fair value	121,862	[1]	26,098	[1]
Liability derivative notional amount	302,211		2,572,227
Liability derivative fair value	2,936	[1]	70,462	[1]
Not Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Asset derivative notional amount	592,791		172,800
Asset derivative fair value	14,797	[1]	1,389	[1]
Liability derivative notional amount	5,804,625		513,512
Liability derivative fair value	28,248	[1]	35,023	[1]
Not Designated as Hedging Instrument \| Investment Related Derivatives \| Interest Rate Contract
Derivatives Fair Value [Line Items]
Asset derivative notional amount	394,597		30,702
Asset derivative fair value	206	[1]	266	[1]
Liability derivative notional amount	20,782		10,259
Liability derivative fair value	51	[1]	8	[1]
Not Designated as Hedging Instrument \| Investment Related Derivatives \| Foreign Exchange Contract
Derivatives Fair Value [Line Items]
Asset derivative notional amount	7,385		17,497
Asset derivative fair value	403	[1]	12	[1]
Liability derivative notional amount	288,376		50,614
Liability derivative fair value	4,724	[1]	680	[1]
Not Designated as Hedging Instrument \| Investment Related Derivatives \| Credit Exposure
Derivatives Fair Value [Line Items]
Asset derivative notional amount	2,408		0
Asset derivative fair value	165	[1]	0	[1]
Liability derivative notional amount	14,270		340,020
Liability derivative fair value	9,836	[1]	15,128	[1]
Not Designated as Hedging Instrument \| Investment Related Derivatives \| Financial Market Exposure
Derivatives Fair Value [Line Items]
Asset derivative notional amount	46,145		58,232
Asset derivative fair value	360	[1]	1,111	[1]
Liability derivative notional amount	33,670		14,821
Liability derivative fair value	34	[1]	77	[1]
Not Designated as Hedging Instrument \| Financial Operations Derivatives \| Credit Exposure
Derivatives Fair Value [Line Items]
Asset derivative notional amount	0	[2]	0	[2]
Asset derivative fair value	0	[1],[2]	0	[1],[2]
Liability derivative notional amount	0	[2]	44,234	[2]
Liability derivative fair value	0	[1],[2]	4,190	[1],[2]
Not Designated as Hedging Instrument \| Other Non Investment Derivatives \| Other Credit Derivatives [Member]
Derivatives Fair Value [Line Items]
Asset derivative notional amount	31,060	[2]	0	[2]
Asset derivative fair value	60	[1],[2]	0	[1],[2]
Liability derivative notional amount	0	[2]	0	[2]
Liability derivative fair value	0	[1],[2]	0	[1],[2]
Not Designated as Hedging Instrument \| Other Non Investment Derivatives \| Guaranteed Minimum Income Benefit
Derivatives Fair Value [Line Items]
Asset derivative notional amount	46,249	[2]	0	[2]
Asset derivative fair value	13,603	[1],[2]	0	[1],[2]
Liability derivative notional amount	46,249	[2]	53,564	[2]
Liability derivative fair value	13,603	[1],[2]	14,940	[1],[2]
Not Designated as Hedging Instrument \| Other Non Investment Derivatives \| Modified Coinsurance Funds Withheld Contract
Derivatives Fair Value [Line Items]
Asset derivative notional amount	64,947	[2],[3]	66,369	[2],[3]
Asset derivative fair value	0	[1],[2],[3]	0	[1],[2],[3]
Liability derivative notional amount	5,401,278	[2]	0	[2],[3]
Liability derivative fair value	$0	[1],[2],[3]	$0	[1],[2],[3]

[1]	Derivative instruments in an asset or liability position are included within Other assets or Other liabilities, respectively, in the balance sheets on a net basis where the Company has both a legal right of offset and the intention to settle the contracts on a net basis.
[2]	Financial operations derivatives represent interests in variable interest entities as described in Note 18, bVariable Interest Entities".
[3]	The fair value movements in derivative assets and liabilities relating to modified coinsurance funds withheld contracts are included within the associated asset or liability at each period end on the face of the balance sheets. Notional amounts associated with reinsurance agreements under which the Company assumes reinsurance risk are recorded as asset derivative notional amounts. Notional amounts associated with the Life Retro Arrangements under which the Company cedes reinsurance risk are recorded as liability derivative notional amounts. Included in the liability derivative notional amount at DecemberB 31, 2014 is the cumulative net realized and unrealized loss on life retrocession embedded derivative of $450.8 million.

Derivative_Instruments_Balance

Derivative Instruments - Balance sheet offsetting (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative assets - gross amounts recognized in the balance sheet	$136,659	$27,487
Derivative assets - gross amounts offset in the balance sheet	696	1,342
Derivative assets - net amounts in the balance sheet	135,963	26,145
Derivative assets - financial instruments not offset in the balance sheet	0	0
Derivative assets - cash collateral not offset in the balance sheet	78,580	0
Derivative assets - net amount	57,383	26,145
Derivative liabilities - gross amounts recognized in the balance sheet	31,184	105,485
Derivative liabilities - gross amounts offset in the balance sheet	696	1,342
Derivative liabilities - net amounts in the balance sheet	30,488	104,143
Derivative liabilities - financial instruments not offset in the balance sheet	0	0
Derivative liabilities - cash collateral not offset in the balance sheet	0	19,847
Derivative liabilities - net amount	$30,488	$84,296

Derivative_Instruments_Hedged_

Derivative Instruments - Hedged items - amount of gain/(loss) recognized in income attributable to risk (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments Gain Loss [Line Items]
Ineffective portion of hedging relationship - gain/(loss)	($256)	$497	($4,585)
Designated as Hedging Instrument \| Fair Value Hedging Member \| Net realized and unrealized gains (losses) on derivative instruments [Member]
Derivative Instruments Gain Loss [Line Items]
Gain (loss) recognized in income on derivative	-15,663	-22,568	-22,370
Ineffective portion of hedging relationship - gain/(loss)	-256	497	-4,585
Designated as Hedging Instrument \| Fair Value Hedging Member \| Net realized and unrealized gains (losses) on derivative instruments [Member] \| Deposit Liabilities
Derivative Instruments Gain Loss [Line Items]
Gain (loss) recognized in income on derivative	0	0	-6,182
Designated as Hedging Instrument \| Fair Value Hedging Member \| Net realized and unrealized gains (losses) on derivative instruments [Member] \| Fixed Maturity Investments
Derivative Instruments Gain Loss [Line Items]
Gain (loss) recognized in income on derivative	15,407	23,065	23,967
Designated as Hedging Instrument \| Fair Value Hedging Member \| Net realized and unrealized gains (losses) on derivative instruments [Member] \| Interest Rate Exposure
Derivative Instruments Gain Loss [Line Items]
Gain (loss) recognized in income on derivative	0	0	1,813
Designated as Hedging Instrument \| Fair Value Hedging Member \| Net realized and unrealized gains (losses) on derivative instruments [Member] \| Foreign Exchange Exposure
Derivative Instruments Gain Loss [Line Items]
Gain (loss) recognized in income on derivative	($15,663)	($22,568)	($24,183)

Derivative_Instruments_Schedul

Derivative Instruments - Schedule of settlement of fair value hedges (Details) (Fair Value Hedging Member, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Notes Payable And Debt
Derivative [Line Items]
Cumulative reduction to interest expense	$21,624	$18,856
Fair Value Hedge Remaining Balance	0	2,767
Weighted average years to maturity	0 years	0 years 8 months 12 days
Deposit Liabilities
Derivative [Line Items]
Cumulative reduction to interest expense	95,333	37,382
Fair Value Hedge Remaining Balance	$137,862	$195,814
Weighted average years to maturity	23 years 2 months 12 days	22 years 8 months 12 days

Derivative_Instruments_Schedul1

Derivative Instruments - Schedule of derivative instruments designated as hedges of the net investment in a foreign operation (Details) (Designated as Hedging Instrument, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Designated as Hedging Instrument
Derivative [Line Items]
Weighted average of U.S. dollar equivalent of foreign denominated net assets	$2,384,508		$2,648,137
Derivative gains (losses)	$120,643	[1]	($27,392)	[1]

[1]	Derivative gains (losses) from derivative instruments designated as hedges of the net investment in a foreign operation are recorded in the cumulative translation adjustment account within AOCI for each period.

Derivative_Instruments_Earning

Derivative Instruments - Earnings relating to derivative instruments not formally designated as hedging instruments (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments Gain Loss [Line Items]
Total derivatives not designated as hedging instruments	$30,142	$7,301	$9,806
Amount of gain (loss) recognized in income from ineffective portion of fair value hedges	-256	497	-4,585
Net realized and unrealized gains (losses) on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets	29,886	7,798	5,221
Not Designated as Hedging Instrument \| Investment Related Derivatives
Derivative Instruments Gain Loss [Line Items]
Interest rate exposure	15,959	5,065	4,394
Foreign exchange exposure	3,351	-948	-1,084
Credit exposure	400	-4,052	-7,611
Financial market exposure	411	6,302	3,073
Not Designated as Hedging Instrument \| Financial Operations Derivatives
Derivative Instruments Gain Loss [Line Items]
Credit exposure	5,023	-2,437	10,511
Not Designated as Hedging Instrument \| Other Non Investment Derivatives
Derivative Instruments Gain Loss [Line Items]
Contingent capital facility	0	0	0
Guaranteed minimum income benefit contract	2,257	10,457	-2,906
Modified coinsurance funds withheld contract	2,741	-7,086	3,429
Life Funds Withheld Assets [Member]
Derivative Instruments Gain Loss [Line Items]
Net realized and unrealized gains (losses) on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets	($488,222)	$0	$0

Derivative_Instruments_Compone

Derivative Instruments - Components of life retrocession embedded derivative (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative [Line Items]
Net realized and unrealized gains (losses) on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets	$29,886	$7,798	$5,221
Life Funds Withheld Assets [Member]
Derivative [Line Items]
Net realized and unrealized gains (losses) on life retrocession embedded derivative	-450,831
Net adjustments related to future policy benefit reserves, net of tax	-21,786
Net realized and unrealized gains (losses) on derivative instruments - Life Funds Withheld Assets	-15,605
Net realized and unrealized gains (losses) on life retrocession embedded derivative and derivative instruments - Life Funds Withheld Assets	-488,222	0	0
Life Funds Withheld Assets [Member] \| Interest income
Derivative [Line Items]
Net realized and unrealized gains (losses) on life retrocession embedded derivative	-134,634
Life Funds Withheld Assets [Member] \| Net realized and unrealized gains (losses
Derivative [Line Items]
Net realized and unrealized gains (losses) on life retrocession embedded derivative	-318,065
Life Funds Withheld Assets [Member] \| Other
Derivative [Line Items]
Net realized and unrealized gains (losses) on life retrocession embedded derivative	$1,868

Derivative_Instruments_Summary

Derivative Instruments - Summary of contingent credit features (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Derivative [Line Items]
Collateral posted to counterparty	$0	$19,847
Contracts with downgrade provisions [Member]
Derivative [Line Items]
Aggregate fair value of derivative agreements with downgrade provisions in a net liability position	5,770	47,703
Collateral posted to counterparty	$0	$13,260

Derivative_Instruments_Narrati

Derivative Instruments - Narrative (Details) (USD $)	12 Months Ended
Derivative Instruments - Narrative (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Derivative [Line Items]
Derivative assets - cash collateral not offset in the balance sheet	$78,580,000		$0
Collateral posted to counterparty	0		19,847,000
Net results from structured products	54,209,000		23,791,000		5,257,000
Asset derivative fair value	136,659,000		27,487,000
Net realized and unrealized gains (losses) on derivative instruments	29,886,000		7,798,000		5,221,000
Deposit Liabilities
Derivative [Line Items]
Periodic coupon settlement decrease to interest expense	0		0		4,900,000
Credit Risk Contract
Derivative [Line Items]
Number of instruments held	1
Deficiency guarantee from German state and federal governments (percentage)	68.00%
Property and casualty operations \| Interest Expense [Member]
Derivative [Line Items]
Net results from structured products	-12,900,000		-48,000,000		-66,300,000
Property and casualty operations \| Interest Expense [Member] \| Structured Indemnity
Derivative [Line Items]
Net results from structured products	28,700,000
Fair Value Hedging Member \| Deposit Liabilities
Derivative [Line Items]
Fair Value Hedge Remaining Balance	137,862,000		195,814,000
Fair Value Hedging Member \| Structured Indemnity \| Deposit Liabilities
Derivative [Line Items]
Fair Value Hedge Remaining Balance	47,000,000
Life Funds Withheld Assets [Member]
Derivative [Line Items]
Net realized and unrealized gains (losses) on life retrocession embedded derivative	-450,831,000
Net realized and unrealized gains (losses) on derivative instruments	-488,222,000		0		0
Not Designated as Hedging Instrument
Derivative [Line Items]
Asset derivative notional amount	592,791,000		172,800,000
Asset derivative fair value	14,797,000	[1]	1,389,000	[1]
Other Non Investment Derivatives \| Not Designated as Hedging Instrument \| Other Credit Derivatives [Member]
Derivative [Line Items]
Asset derivative notional amount	31,060,000	[2]	0	[2]
Asset derivative fair value	60,000	[1],[2]	0	[1],[2]
Net realized and unrealized gains (losses) on derivative instruments	$100,000	[1],[2]

[1]	Derivative instruments in an asset or liability position are included within Other assets or Other liabilities, respectively, in the balance sheets on a net basis where the Company has both a legal right of offset and the intention to settle the contracts on a net basis.
[2]	Financial operations derivatives represent interests in variable interest entities as described in Note 18, bVariable Interest Entities".

Variable_Interest_Entities_Det

Variable Interest Entities (Details) (Variable Interest Entity, Primary Beneficiary, USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
New Ocean Capital Management Ltd
Variable Interest Entity [Line Items]
Non-controlling interest in consolidated subsidiaries	$0.20	$0.30
New Ocean Focus Cat Fund
Variable Interest Entity [Line Items]
Total assets of consolidated entity	93.9	46.5
Non-controlling interest in consolidated subsidiaries	57.4	6.9
New Ocean Market Value Cat Fund [Member]
Variable Interest Entity [Line Items]
Total assets of consolidated entity	46.1
Non-controlling interest in consolidated subsidiaries	$1

Commitments_and_Contingencies_1

Commitments and Contingencies - Broker credit risk (Details) (Gross written premium, Property and casualty operations, Credit concentration risk)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Concentration Risk [Line Items]
Percentage of gross written premiums	10.00%
AON Corporation and subsidiaries
Concentration Risk [Line Items]
Percentage of gross written premiums	18.00%	21.00%	22.00%
Marsh & McLennan Companies
Concentration Risk [Line Items]
Percentage of gross written premiums	20.00%	23.00%	21.00%
Willis Group and subsidiaries
Concentration Risk [Line Items]
Percentage of gross written premiums	11.00%	13.00%	11.00%

Commitments_and_Contingencies_2

Commitments and Contingencies - Future minimum operating lease payments (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified	Dec. 31, 2014
Future minimum payments on operating leases:
2015	$36,949
2016	32,027
2017	28,933
2018	25,156
2019	24,086
2020-2031	73,269
Total minimum future rentals	$220,420

Commitments_and_Contingencies_3

Commitments and Contingencies - Future minimum capital lease payments (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified	Dec. 31, 2014
Future minimum payments on capital leases:
2015	$12,095
2016	12,398
2017	12,708
2018	13,025
2019	13,351
2020 - 2031	127,787
Total minimum future lease payments	$191,364

Commitments_and_Contingencies_4

Commitments and Contingencies - Financial and other guarantee exposures(Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
	Guarantee_contracts	Guarantee_contracts
Commitments and Contingencies Disclosure [Abstract]
Number of financial guarantee contracts at beginning of period	3	4
Number of financial guarantee contracts matured, prepaid or commuted during the period	-1	-1
Number of financial guarantee contracts at end of period	2	3
Principal outstanding	$80,813	$108,255
Interest outstanding	0	0
Aggregate exposure outstanding	80,813	108,255
Total gross claim liability recorded	0	0
Total unearned premiums and fees recorded	$0	$134
Weighted average contractual term to maturity in years	25 years 2 months 12 days	26 years 0 months 0 days

Commitments_and_Contingencies_5

Commitments and Contingencies - Narrative (Details) (USD $)	12 Months Ended
Commitments and Contingencies - Narrative (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Commitments And Contingencies Disclosure [Line Items]
Additional investment commitment - other investments	$107,300,000
Time period over which commitment exists - limited partnerships	7 years 8 months 12 days
Additional investment commitment - investments in affiliates	112,800,000
Time period over which commitment exists, investments in affiliates	6 years 10 months 24 days
Maximum percentage tax on branch profits, contingent	30.00%
Total rent expense under operating leases	36,600,000		38,700,000		35,600,000
Capital lease asset recognized	82,800,000		94,400,000
Deferred gain on sale/leaseback transaction	25,200,000		28,700,000
Future minimum lease payments	191,364,000
Shareholders' equity \| Credit concentration risk
Commitments And Contingencies Disclosure [Line Items]
Maximum percentage of aggregate direct investment in any single corporate issuer	5.00%
Letter of credit facility
Commitments And Contingencies Disclosure [Line Items]
Letters of credit, amount outstanding	$1,790,561,000	[1],[2]	$1,895,425,000	[1],[2]
Percentage of letters of credit collateralized by investment portfolios	66.20%	[1]	67.60%	[1]

[1]	At December 31, 2014, there were eight available letter of credit facilities; at December 31, 2013, there were seven available letter of credit facilities.
[2]	bIn Useb and bOutstandingb data represent December 31, 2014 and 2013 accreted values.

Share_Capital_Authorized_and_i

Share Capital - Authorized and issued (Details)

12 Months Ended

0 Months Ended

12 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2014

Oct. 15, 2011

Mar. 15, 2007

Dec. 31, 2013

Feb. 22, 2013

Dec. 31, 2014

Feb. 21, 2014

USD ($)

EUR (€)

USD ($)

Ordinary Shares

Undesignated shares

Subscriber shares

Series D preference ordinary shares

Series E preference ordinary shares

February 2013 share repurchase plan

Two Thousand Fourteen Share Repurchase Authorization [Member]

USD ($)

EUR (€)

USD ($)

LIBOR

USD ($)

Shareholders Equity Disclosure [Line Items]

Authorized share capital, value

$9,999,900

€ 40,000

Ordinary shares, shares authorized (in shares)

999,990,000

500,000,000

499,990,000

40,000

Ordinary shares, par value (in dollars per share)

$0.01

€ 1

Rollforward of ordinary shares issued and outstanding:

Balance at beginning of year, shares

278,253,308

298,682,000

Exercise of options, shares

424,000

927,000

Net issuance of restricted shares, shares

1,246,000

1,240,000

Share buybacks, shares

-24,740,000

[1]

-24,740,000

[1]

-22,596,000

[1]

Balance at end of year, shares

255,182,955

278,253,308

Ordinary share buybacks:

Share repurchase authorization

850,000,000

1,000,000,000

Shares purchased and canceled during the period

24,700,000

Value of shares purchased and canceled during the period

800,000,000

Average price per share of shares repurchased and canceled during the period

$32.40

Amount remaining under share repurchase plan

275,000,000

267,600,000

200,000,000

Preferred shares and non-controlling interest in equity of consolidated subsidiaries:

Shares purchased and canceled during the period

24,700,000

Liquidation preference per share

$1,000

Preferred shares, shares issued

1,000,000

Preferred shares, stated dividend per share

$32.50

Dividend rate, spread on LIBOR

3.12%

Preferred shares, par value

$0.01

Proceeds on issuance of preferred shares

350,000,000

983,800,000

Face value of notes repaid

$600,000,000

Articles Of Association maximum voting power, percentage

10.00%

[1]

Includes share buybacks associated with authorized share buyback programs as well as purchases related to satisfying tax withholding obligations of employees in connection with the vesting of restricted shares granted under the Companybs equity compensation programs.

Share_Capital_Options_valuatio

Share Capital - Options valuation assumptions (Details) (Stock options)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock options
Weighted average assumptions and option awards:
Dividend yield	2.00%	2.00%	1.90%
Risk free interest rate	1.81%	1.14%	1.15%
Volatility	34.00%	37.00%	46.00%
Expected lives	6 years	6 years	6 years

Share_Capital_Options_Details

Share Capital - Options (Details) (USD $)	12 Months Ended
Share Capital - Options (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2004
Summary of stock option plans:
Options exercised during the year	424,000		927,000
Summary of stock options and related activity:
Options exercised during the year	-424,000		-927,000
Stock Options Member
Summary of stock option plans:
Options granted to purchase ordinary shares under directors and employees incentive compensation plans (shares)	1,025,000		1,047,000	1,209,000
Weighted average grant date fair value (per share)	$8.60		$8.34	$7.65
Total intrinsic value of stock options exercised	$7,499,000		$16,076,000	$3,357,000
Options exercised during the year	424,000		927,000	383,000
Compensation expense related to stock option plans	9,961,000		8,294,000	7,716,000
Estimated tax benefit related to stock option plans	-2,000		50,000	26,000
Summary of stock options and related activity:
Outstanding at beginning of year, shares	11,123,000
Granted, shares	1,025,000
Options exercised during the year	-424,000		-927,000	-383,000
Canceled/expired, shares	-1,199,000
Outstanding at end of year, shares	10,525,000		11,123,000
Options exercisable, shares	8,400,000
Options available for grant, shares	10,316,000	[1]
Outstanding at beginning of year, weighted average exercise price	$36.91
Granted, weighted average exercise price	$30.42
Exercised, weighted average exercise price	$15.04
Canceled/expired, weighted average exercise price	$78.46
Outstanding at end of year, weighted average exercise price	$32.42		$36.91
Options exercisable, weighted average exercise price	$33.53
Weighted average remaining contractual term, beginning of year	4 years 9 months 18 days		4 years 9 months 18 days
Weighted average remaining contractual term, end of year	4 years 9 months 18 days		4 years 9 months 18 days
Weighted average remaining contractual term, options exercisable	3 years 10 months 24 days
Aggregate intrinsic value, beginning of year	74,927,000
Aggregate intrinsic value, end of year	86,690,000		74,927,000
Aggregate intrinsic value, options exercisable	73,153,000
Total unrecognized stock based compensation expense	$10,400,000
Number of non-vested options outstanding	2,100,000
Period for recognition of unrecognized expense	1 year 3 months 18 days
Number of stock options issued at an exercise price other than market price					295,000
Exercise price of options issued at above market price					$88
Market price at time of grant					$77.10

[1]	Available for grant includes shares that may be granted as either stock options, restricted stock, restricted stock units or performance units.

Share_Capital_Restricted_stock

Share Capital - Restricted stock, restricted stock units and performance units (Details) (USD $)	12 Months Ended
Share data in Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Minimum
Summary of awards:
Vesting period required	3 years
Maximum
Summary of awards:
Vesting period required	4 years
Restricted stock awards
Summary of awards:
Granted (in Shares)	46	181	325
Weighted average grant date fair value (per share)	$31.86	$29.44	$20.92
Aggregate grant date fair value	$1,463,000	$5,325,000	$6,811,000
Compensation expense	5,239,000	4,419,000	5,399,000
Estimated tax benefit (charge)	1,233,000	1,047,000	1,113,000
Total unrecognized stock based compensation expense	2,500,000
Period for recognition of unrecognized expense	1 year
Award activity:
Unvested at beginning of period, shares	593
Granted, shares	46	181	325
Vested, shares	-201
Forfeited, shares	-5
Unvested at end of period, shares	433	593
Unvested at beginning of period, weighted average grant date fair value	$33.92
Granted, weighted average grant date fair value	$31.86
Vested, weighted average grant date fair value	$27.79
Forfeited, weighted average grant date fair value	$44.01
Unvested at end of period, weighted average grant date fair value	$36.41	$33.92
Restricted stock units
Summary of awards:
Granted (in Shares)	1,867	1,803	1,312
Aggregate grant date fair value	57,134,000	51,829,000	27,194,000
Compensation expense	41,879,000	32,874,000	24,451,000
Estimated tax benefit (charge)	11,607,000	8,813,000	6,501,000
Total unrecognized stock based compensation expense	60,100,000
Period for recognition of unrecognized expense	1 year 4 months 24 days
Vesting period required	3 years
Award activity:
Unvested at beginning of period, shares	2,931
Granted, shares	1,867	1,803	1,312
Vested, shares	-1,388
Forfeited, shares	-162
Unvested at end of period, shares	3,248	2,931
Unvested at beginning of period, weighted average grant date fair value	$25.77
Granted, weighted average grant date fair value	$30.60
Vested, weighted average grant date fair value	$24.80
Forfeited, weighted average grant date fair value	$28.05
Unvested at end of period, weighted average grant date fair value	$28.93	$25.77
Performance units
Summary of awards:
Granted (in Shares)	572	656	1,527
Potential maximum share payout	1,144	1,312	3,054
Aggregate grant date fair value	16,345,000	17,753,000	29,537,000
Compensation expense	24,089,000	1,041,000	9,919,000
Estimated tax benefit (charge)	4,250,000	-176,000	1,943,000
Total unrecognized stock based compensation expense	$27,800,000
Period for recognition of unrecognized expense	1 year 9 months 18 days
Vesting period required	3 years
Award activity:
Unvested at beginning of period, shares	1,687
Granted, shares	572	656	1,527
Vested, shares	-340
Forfeited, shares	-100
Performance driven reduction, shares	721
Unvested at end of period, shares	2,540	1,687
Unvested at beginning of period, weighted average grant date fair value	$22.99
Granted, weighted average grant date fair value	$28.57
Vested, weighted average grant date fair value	$22.06
Forfeited, weighted average grant date fair value	$25.98
Performance driven reduction, weighted average grant date fair value	$26.46
Unvested at end of period, weighted average grant date fair value	$25.24	$22.99
Performance units \| Minimum
Summary of awards:
Final payout percentage	0.00%
Performance units \| Maximum
Summary of awards:
Final payout percentage	200.00%

Retirement_Plans_Funded_status

Retirement Plans - Funded status of plan by geographic location (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Funded status - end of year	($43,843)	($34,818)
US Plan
Defined Benefit Plan Disclosure [Line Items]
Funded status - end of year	-13,124	-6,181
UK Plans
Defined Benefit Plan Disclosure [Line Items]
Funded status - end of year	-7,742	-7,654
Europe plans
Defined Benefit Plan Disclosure [Line Items]
Funded status - end of year	($22,977)	($20,983)

Retirement_Plans_Projected_ben

Retirement Plans - Projected benefit obligation and plan assets (Details) (Defined benefit plan, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Defined benefit plan
Change in projected benefit obligation:
Projected benefit obligation, beginning of year	$81,976		$83,083
Service cost	1,279	[1]	1,491	[1]	1,291
Interest cost	3,747		3,599
Actuarial (gain) loss	13,402		-5,091
Benefits and expenses paid	-2,761		-2,307
Foreign currency (gains) losses	-3,817		1,201
Settlements	-702		0
Projected benefit obligation, end of year	93,124		81,976		83,083
Change in plan assets:
Fair value of plan assets - beginning of year	47,158		39,313
Actual return on plan assets	3,543		6,113
Employer contributions	1,187		2,919
Benefits and expenses paid	-1,932		-1,462
Foreign currency (gains) losses	-675		275
Fair value of plan assets - end of year	49,281		47,158		39,313
Funded status - end of year	-43,843		-34,818
Accrued pension liability	$43,843		$34,818

[1]	Service costs include cost of living adjustments on curtailed plans.

Retirement_Plans_Net_benefit_c

Retirement Plans - Net benefit cost (Details) (Defined benefit plan, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$1,279	[1]	$1,491	[1]	$1,291
Interest cost	3,747		3,589		3,557
Expected return on plan assets	-2,859		-3,096		-3,028
Amortization of net actuarial loss	812		1,440		915
Transfer from AOCI	0		0		3,363
Net benefit cost	$2,979		$3,424		$6,098

[1]	Service costs include cost of living adjustments on curtailed plans.

Retirement_Plans_Assumptions_u

Retirement Plans - Assumptions used (Details)	12 Months Ended
Retirement Plans - Assumptions used (Details)	Dec. 31, 2014	Dec. 31, 2013
US Plan
Net benefit cost - weighted average assumptions
Discount rate	4.95%	4.00%
Expected long-term rate of return on plan assets	6.50%	8.00%
Benefit obligation - weighted-average assumptions
Discount rate	3.91%	4.95%
UK Plans
Net benefit cost - weighted average assumptions
Discount rate	4.60%	4.50%
Expected long-term rate of return on plan assets	4.60%	5.70%
Rate of compensation increase	5.50%	4.90%
Benefit obligation - weighted-average assumptions
Discount rate	4.60%	4.50%
Rate of compensation increase	5.50%	4.90%
Europe plans
Net benefit cost - weighted average assumptions
Discount rate	3.50%	4.20%
Rate of compensation increase	2.50%	2.50%
Benefit obligation - weighted-average assumptions
Discount rate	2.40%	3.50%
Rate of compensation increase	2.50%	2.50%

Retirement_Plans_UK_plans_Deta

Retirement Plans - UK plans (Details) (UK Plans, USD $)	12 Months Ended
Retirement Plans - UK plans (Details) (UK Plans, USD $)	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$11,184,000	$10,714,000
Funding deficit based on most recent valuation	2,400,000
Period over which the deficit is being funded	10 years
Transferred to defined contribution plan
Defined Benefit Plan Disclosure [Line Items]
Number of members in the plan	6
Accrued pension liability	3,800,000	4,000,000
Still employed by company
Defined Benefit Plan Disclosure [Line Items]
Number of members in the plan	4
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	7.40%	6.80%
Fair value of plan assets	7,787,000	7,048,000
Gilts
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	3.60%	3.00%
Fair value of plan assets	1,579,000	1,775,000
Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	4.60%	4.50%
Fair value of plan assets	1,594,000	1,758,000
Other (cash)
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	4.00%	3.40%
Fair value of plan assets	$224,000	$133,000

Retirement_Plans_Expected_futu

Retirement Plans - Expected future benefit payments of US plan (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
2015	$1,301
2016	1,350
2017	1,422
2018	1,488
2019	1,777
2020 - 2024	12,389
US Plan
Defined Benefit Plan Disclosure [Line Items]
2015	876
2016	925
2017	1,001
2018	1,064
2019	1,255
2020 - 2024	9,462
Benefits equalization plan
Defined Benefit Plan Disclosure [Line Items]
2015	425
2016	425
2017	421
2018	424
2019	522
2020 - 2024	$2,927

Retirement_Plans_Narrative_Det

Retirement Plans - Narrative (Details) (USD $)	12 Months Ended
Retirement Plans - Narrative (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Vesting period for defined contribution plan	5 years
Expense recognized on defined contribution plans	$56,600,000	$49,400,000	$53,600,000
Number of years of compensation for calculating benefit	3 years
Number of years of employment considered at retirement	10 years
Estimated employer contributions in next fiscal year	400,000
US Plan
Defined Benefit Plan Disclosure [Line Items]
Number of mutual funds held by plan	2	2
Fair value of plan assets	38,100,000	36,400,000
Benefits equalization plan
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$3,200,000	$3,000,000

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income - Changes in AOCI, net of tax (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, net of tax, beginning of period	$736,657,000		$1,520,020,000		$583,065,000
OCI before reclassifications	916,952,000		-795,980,000		970,627,000
Amounts reclassified from AOCI	-128,094,000		-85,692,000		-9,036,000
Tax (benefit) expense	-41,057,000		98,309,000		-24,636,000
Net current period OCI - net of tax	747,801,000		-783,363,000		936,955,000
Balance, net of tax, end of period	1,484,458,000		736,657,000		1,520,020,000
Cumulative adjustments recorded to value of future policy benefit reserves, amount	400,456,000		44,660,000		0
Unrealized Gains (Losses) on Investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, net of tax, beginning of period	822,432,000	[1]	1,591,210,000	[1]	710,447,000	[1]
OCI before reclassifications	954,326,000	[1]	-742,768,000	[1]	985,544,000	[1]
Amounts reclassified from AOCI	-143,330,000	[1]	-119,970,000	[1]	-81,678,000	[1]
Tax (benefit) expense	-43,314,000	[1]	93,960,000	[1]	-23,103,000	[1]
Net current period OCI - net of tax	767,682,000	[1]	-768,778,000	[1]	880,763,000	[1]
Balance, net of tax, end of period	1,590,114,000	[1]	822,432,000	[1]	1,591,210,000	[1]
Cumulative adjustments recorded to value of future policy benefit reserves, amount	400,456,000
Cumulative impact of net unrealized gains (losses) on future policy benefit reserve	445,100,000		44,700,000
OTTI Losses Recognized in AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, net of tax, beginning of period	-89,190,000		-121,371,000		-188,651,000
OCI before reclassifications	0		0		0
Amounts reclassified from AOCI	14,082,000		32,193,000		67,580,000
Tax (benefit) expense	-939,000		-12,000		-300,000
Net current period OCI - net of tax	13,143,000		32,181,000		67,280,000
Balance, net of tax, end of period	-76,047,000		-89,190,000		-121,371,000
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, net of tax, beginning of period	14,541,000		69,399,000		77,555,000
OCI before reclassifications	-26,497,000		-62,934,000		-6,791,000
Amounts reclassified from AOCI	87,000		206,000		350,000
Tax (benefit) expense	681,000		7,870,000		-1,715,000
Net current period OCI - net of tax	-25,729,000		-54,858,000		-8,156,000
Balance, net of tax, end of period	-11,188,000		14,541,000		69,399,000
Underfunded Pension Liability
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, net of tax, beginning of period	-13,239,000		-20,892,000		-17,521,000
OCI before reclassifications	-10,877,000		9,722,000		-8,126,000
Amounts reclassified from AOCI	812,000		1,440,000		4,273,000
Tax (benefit) expense	2,515,000		-3,509,000		482,000
Net current period OCI - net of tax	-7,550,000		7,653,000		-3,371,000
Balance, net of tax, end of period	-20,789,000		-13,239,000		-20,892,000
Cash Flow Hedge
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, net of tax, beginning of period	2,113,000		1,674,000		1,235,000
OCI before reclassifications	0		0		0
Amounts reclassified from AOCI	255,000		439,000		439,000
Tax (benefit) expense	0		0		0
Net current period OCI - net of tax	255,000		439,000		439,000
Balance, net of tax, end of period	$2,368,000		$2,113,000		$1,674,000

[1]	Included in these amounts is the impact of Shadow Adjustments. During the year ended December 31, 2013, the initial impact of $44.7 million was recorded. During the year ended DecemberB 31, 2014, additional net impacts of $400.5 million were recorded, resulting in a total cumulative net impact of Shadow Adjustments on future policy benefit reserves of $445.1 million at DecemberB 31, 2014.

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive Income - Details about AOCI components (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized and unrealized gains (losses) on derivative instruments	$29,886		$7,798		$5,221
Operating Expenses	-1,341,315		-1,213,178		-1,173,955
Exchange gains (losses) before tax	37,568		28,243		-10,545
Amounts reclassified from AOCI	-128,094		-85,692		-9,036
Provision for income tax	-96,897		-77,505		-34,028
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	-128,094		-85,692
Provision for income tax	-1,974		5,171
Total amount reclassified from AOCI, net of tax	-130,068		-80,521
Unrealized Gains (Losses) on Investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized gains (losses) on investments sold	-175,639		-130,236
OTTI on investments	54,095		10,266
Amounts reclassified from AOCI	-143,330	[1]	-119,970	[1]	-81,678	[1]
Provision for income tax	-1,593		5,183
Total amount reclassified from AOCI, net of tax	-144,923		-114,787
OTTI Losses Recognized in AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	14,082		32,193		67,580
OTTI Losses Recognized in AOCI \| Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized gains (losses) on investments sold	11,848		26,160
OTTI on investments	2,234		6,033
Amounts reclassified from AOCI	14,082		32,193
Provision for income tax	-175		-12
Total amount reclassified from AOCI, net of tax	13,907		32,181
Foreign Currency Translation Adjustments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	87		206		350
Foreign Currency Translation Adjustments \| Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	87		206
Provision for income tax	0		0
Total amount reclassified from AOCI, net of tax	87		206
Underfunded Pension Liability
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	812		1,440		4,273
Underfunded Pension Liability \| Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operating Expenses	812		1,440
Provision for income tax	-206		0
Total amount reclassified from AOCI, net of tax	606		1,440
Cash Flow Hedge
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	255		439		439
Cash Flow Hedge \| Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	255		439
Provision for income tax	0		0
Total amount reclassified from AOCI, net of tax	255		439
Life Funds Withheld Assets [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized gains (losses) on investments sold	5,067		0		0
OTTI on investments	-20,587		0		0
Net realized and unrealized gains (losses) on derivative instruments	-488,222		0		0
Life Funds Withheld Assets [Member] \| Unrealized Gains (Losses) on Investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized and unrealized gains (losses) on derivative instruments	($21,786)		$0

[1]	Included in these amounts is the impact of Shadow Adjustments. During the year ended December 31, 2013, the initial impact of $44.7 million was recorded. During the year ended DecemberB 31, 2014, additional net impacts of $400.5 million were recorded, resulting in a total cumulative net impact of Shadow Adjustments on future policy benefit reserves of $445.1 million at DecemberB 31, 2014.

Dividends_Details

Dividends (Details) (USD $)

12 Months Ended

3 Months Ended

9 Months Ended

In Millions, except Per Share data, unless otherwise specified

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2014

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Jun. 30, 2012

Mar. 31, 2012

Sep. 30, 2012

Oct. 31, 2014

Feb. 20, 2015

Dividends Paid [Line Items]

Dividends per share paid on ordinary shares

$0.64

$0.56

$0.44

Ordinary Shares

Dividends Paid [Line Items]

Dividends per share paid on ordinary shares

$0.16

$0.14

$0.11

Series D preference ordinary shares

Dividends Paid [Line Items]

Dividends on preference ordinary shares

$11.70

[1],[2]

$12.30

[1],[2]

$14

[1],[2]

Dividends declared and payable per share

$8.56

Series E preference ordinary shares

Dividends Paid [Line Items]

Dividends on preference ordinary shares

$65.10

[3]

$65.10

[3]

$65.10

[3]

Subsequent Event [Member] | Series D preference ordinary shares

Dividends Paid [Line Items]

Dividends declared and payable per share

$8.43

Subsequent Event [Member] | Series E preference ordinary shares

Dividends Paid [Line Items]

Dividends declared and payable per share

$32.50

[1]

On OctoberB 31, 2014, the Company announced that the Board of Directors of XL-Cayman resolved to pay a dividend of $8.5563 per share on XL-Caymanbs Series D Preference Ordinary Shares. The dividend was paid on JanuaryB 15, 2015 to all shareholders of record at JanuaryB 1, 2015.

[2]

On FebruaryB 20, 2015, the Company announced that the Board of Directors of XL-Cayman, resolved on FebruaryB 19, 2015 to pay a dividend of $8.4315 per share on XL-Caymanbs Series D Preference Ordinary Shares. The dividend will be paid on AprilB 15, 2015 to all shareholders of record at AprilB 1, 2015.

[3]

On FebruaryB 20, 2015, the Company announced that the Board of Directors of XL-Cayman, resolved on FebruaryB 19, 2015 to pay a dividend of $32.50 per share on XL-Caymanbs Series E Preference Ordinary Shares. The dividend will be paid on AprilB 15, 2015 to all shareholders of record at AprilB 1, 2015.

Taxation_Summary_of_tax_years_

Taxation - Summary of tax years open to examination by jurisdiction (Details)	12 Months Ended
	Dec. 31, 2014
United States
Income Tax Examination [Line Items]
Year under Examination	2013
United States \| Minimum
Income Tax Examination [Line Items]
Open Tax Year	2011
United States \| Maximum
Income Tax Examination [Line Items]
Open Tax Year	2014
Ireland \| Minimum
Income Tax Examination [Line Items]
Year under Examination	2006
Open Tax Year	2006
Ireland \| Maximum
Income Tax Examination [Line Items]
Year under Examination	2009
Open Tax Year	2014
United Kingdom \| Minimum
Income Tax Examination [Line Items]
Year under Examination	2007
Open Tax Year	2012
United Kingdom \| Maximum
Income Tax Examination [Line Items]
Year under Examination	2010
Open Tax Year	2014
Germany \| Minimum
Income Tax Examination [Line Items]
Year under Examination	2006
Open Tax Year	2007
Germany \| Maximum
Income Tax Examination [Line Items]
Year under Examination	2009
Open Tax Year	2014
Switzerland \| Minimum
Income Tax Examination [Line Items]
Year under Examination	2009
Open Tax Year	2009
Switzerland \| Maximum
Income Tax Examination [Line Items]
Year under Examination	2010
Open Tax Year	2014
France \| Minimum
Income Tax Examination [Line Items]
Open Tax Year	2012
France \| Maximum
Income Tax Examination [Line Items]
Open Tax Year	2014

Taxation_Distribution_of_preta

Taxation - Distribution of pre-tax income by jurisdiction and components of income tax (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Distribution of pre-tax income by jurisdiction:
U.S.	$228,708	$188,503	$50,439
Non U.S.	137,027	1,025,649	713,972
Income (loss) before income taxes	365,735	1,214,152	764,411
Current expense:
U.S.	45,598	49,566	11,966
Non U.S.	81,371	41,921	45,614
Total current expense	126,969	91,487	57,580
Deferred expense (benefit):
U.S.	8,572	700	-56,602
Non U.S.	-38,644	-14,682	33,050
Total deferred expense (benefit)	-30,072	-13,982	-23,552
Total Tax Expense	$96,897	$77,505	$34,028

Taxation_Tax_rates_by_jurisdic

Taxation - Tax rates by jurisdiction (Details)	12 Months Ended
Taxation - Tax rates by jurisdiction (Details)	Dec. 31, 2014
Ireland \| Active income
Income Tax Disclosure [Line Items]
Applicable statutory tax rate, by jurisdiction	12.50%	[1]
Ireland \| Passive income
Income Tax Disclosure [Line Items]
Applicable statutory tax rate, by jurisdiction	25.00%	[1]
Bermuda
Income Tax Disclosure [Line Items]
Applicable statutory tax rate, by jurisdiction	0.00%
United States
Income Tax Disclosure [Line Items]
Applicable statutory tax rate, by jurisdiction	35.00%
United Kingdom
Income Tax Disclosure [Line Items]
Applicable statutory tax rate, by jurisdiction	21.50%
Switzerland \| Active income
Income Tax Disclosure [Line Items]
Applicable statutory tax rate, by jurisdiction	7.83%	[2]
Switzerland \| Passive income
Income Tax Disclosure [Line Items]
Applicable statutory tax rate, by jurisdiction	21.20%	[2]
Germany
Income Tax Disclosure [Line Items]
Applicable statutory tax rate, by jurisdiction	15.00%
France
Income Tax Disclosure [Line Items]
Applicable statutory tax rate, by jurisdiction	38.00%

[1]	The different applicable statutory taxation rates in Ireland relate to entities classified as trading or non-trading companies.
[2]	The different applicable statutory taxation rates in Switzerland relate to entities classified as trading or holding companies.

Taxation_Reconciliation_of_eff

Taxation - Reconciliation of effective tax rate (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Expected tax provision at weighted average rate	$132,775	$43,092	$53,358
Permanent differences:
Non taxable (income) loss	-19,870	-50,745	-42,428
Prior year adjustments	5,990	6,067	-622
Prior year adjustments on completion of IRS examinations	0	0	-19,192
State, local and foreign taxes	47,078	12,225	18,312
Valuation allowance	-181	5,754	-16,644
Net allocated investment income	3,399	5,949	41,727
Stock options	411	1,501	4,749
Non-deductible expenses	22,556	23,662	16,145
Realized capital loss carry-forward valuation allowance reduction	-2,916	0	-24,473
Adjustments related to Life Retro Arrangements	-99,535	0	0
Non-taxable reserve release	0	0	3,096
Uncertain tax positions	7,190	30,000	0
Total Tax Expense	$96,897	$77,505	$34,028

Taxation_Components_of_deferre

Taxation - Components of deferred tax assets and liabilities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Net unpaid loss reserve discount	$90,262	$105,511
Net unearned premiums	72,752	69,811
Compensation liabilities	77,578	62,710
Net operating loss	49,834	89,233
Investment adjustments	13,022	12,573
Pension	8,114	5,695
Bad debt reserve	6,626	7,337
Amortizable goodwill	6,694	7,976
Net unrealized depreciation on investments	1,484	9,984
Stock options	11,985	12,171
Depreciation	7,599	3,501
Net realized capital losses	97,189	140,993
Deferred intercompany capital losses	57,427	69,500
Untaxed Lloyd's result	7,254	2,533
Deferred acquisition costs	11,386	0
Other	2,282	9,638
Deferred tax asset, gross of valuation allowance	521,488	609,166
Valuation allowance	207,062	261,924
Deferred tax asset, net of valuation allowance	314,426	347,242
Deferred tax liabilities:
Net unrealized appreciation on investments	63,642	28,843
Unremitted earnings	5,125	6,717
Deferred acquisition costs	2,737	7,057
Currency translation adjustments	3,969	7,195
Regulatory reserves	65,965	131,750
Investment adjustment	12,061	6,112
Untaxed Lloyd's result	11,422	0
Other	11,260	8,014
Deferred tax liability	176,181	195,688
Net deferred tax assets	$138,245	$151,554

Taxation_Summary_of_valuation_

Taxation - Summary of valuation allowance (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Valuation Allowance [Line Items]
Valuation allowance	$207,062	$261,924
Switzerland
Valuation Allowance [Line Items]
Valuation allowance	1,459	11,457
Ireland
Valuation Allowance [Line Items]
Valuation allowance	72,363	60,133
United States
Valuation Allowance [Line Items]
Valuation allowance	123,695	175,372
Other
Valuation Allowance [Line Items]
Valuation allowance	$9,545	$14,962

Taxation_Reconciliation_of_unr

Taxation - Reconciliation of unrecognized tax benefits (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, beginning of the year	$30,000	$0
Increases for tax positions taken during the year	12,182	9,591
Increases for tax positions taken in prior years	15,304	20,409
Decreases for tax positions taken during the year	0	0
Decreases for tax positions taken in prior years	-20,296	0
Decreases for settlement with taxing authorities	0	0
Decreases for lapse of the applicable statute of limitations	0	0
Unrecognized tax benefits, end of the year	$37,190	$30,000

Taxation_Narrative_Details

Taxation - Narrative (Details) (USD $)	12 Months Ended
Taxation - Narrative (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Line Items]
Deferred tax asset, per balance sheet	$204,491,000	$237,884,000
Deferred tax liability, per balance sheet	66,246,000	86,330,000
Valuation allowance	207,062,000	261,924,000
Increase (decrease) in valuation allowance, amount	54,900,000
Net realized capital losses	97,189,000	140,993,000
Excess tax benefits on share-based compensation	4,000,000	1,800,000
Accrued interest and penalties	400,000	1,000,000
Unrecognized tax benefits	37,190,000	30,000,000	0
United States
Income Tax Disclosure [Line Items]
Valuation allowance	123,695,000	175,372,000
Capital loss valuation allowance, amount	61,100,000
Capital loss carryforwards available	174,600,000
Net operating loss carryforwards, tax effected	61,100,000
United States \| Deferred intercompany capital losses
Income Tax Disclosure [Line Items]
Capital loss valuation allowance, amount	57,400,000
Capital loss carryforwards, tax effected	57,400,000
Capital loss carryforwards available	164,100,000
United States \| Expiring in 2015
Income Tax Disclosure [Line Items]
Capital loss carryforwards available	75,600,000
United States \| Expiring in future years
Income Tax Disclosure [Line Items]
Capital loss carryforwards available	99,000,000
Ireland
Income Tax Disclosure [Line Items]
Valuation allowance	72,363,000	60,133,000
Capital loss carryforwards available	153,500,000
Net operating loss carryforwards, amount	280,800,000
Net operating loss carryforwards valuation allowance, amount	69,600,000
United Kingdom
Income Tax Disclosure [Line Items]
Capital loss carryforwards, tax effected	1,600,000
Net operating loss carryforwards, amount	84,500,000
Net operating loss carryforwards valuation allowance, amount	1,600,000
Net operating loss carryforwards, tax effected	1,900,000
Net realized capital losses	8,100,000
United Kingdom \| Uncertain Tax Position [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards, tax effected	15,000,000
United Kingdom \| Excluding Uncertain Tax Position [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards, tax effected	16,900,000
United Kingdom \| Expected to be used
Income Tax Disclosure [Line Items]
Net operating loss carryforwards, amount	84,500,000
Switzerland
Income Tax Disclosure [Line Items]
Valuation allowance	1,459,000	11,457,000
Net operating loss carryforwards, amount	12,100,000
Net operating loss carryforwards valuation allowance, amount	800,000
Switzerland \| Not expected to be utilized in the future
Income Tax Disclosure [Line Items]
Net operating loss carryforwards, amount	$11,700,000

Statutory_Financial_Data_Detai

Statutory Financial Data (Details) (USD $)	12 Months Ended
Statutory Financial Data (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
XL-Ireland
Statutory Accounting Practices [Line Items]
Cash and investments, net of liabilities associated with cash sweeping arrangements	$22,400,000		$12,700,000
XL-Cayman
Statutory Accounting Practices [Line Items]
Cash and investments, net of liabilities associated with cash sweeping arrangements	900,000,000		1,600,000,000
Bermuda
Statutory Accounting Practices [Line Items]
Required statutory capital and surplus	6,194,832,000	[1]	6,583,273,000	[1]
Actual statutory capital and surplus	10,309,895,000	[1],[2]	10,168,744,000	[1],[2]
Statutory net income (loss)	361,033,000		1,241,878,000		857,832,000
BSCR level for principal operating subsidiaries	100.00%
Maximum permitted dividends as a percentage of prior year statutory capital and surplus	25.00%
Maximum permitted dividends as a percentage of statutory capital	15.00%
Maximum dividend permitted without affidavit	1,400,000,000		1,400,000,000
United States
Statutory Accounting Practices [Line Items]
Required statutory capital and surplus	668,794,000	[3]	657,865,000	[3]
Actual statutory capital and surplus	2,233,596,000	[2],[3]	2,244,505,000	[2],[3]
Statutory net income (loss)	155,751,000		124,310,000		106,510,000
RBC level for certain operating subsidiaries	100.00%
Maximum permitted dividends as a percentage of statutory policyholder surplus	10.00%
Maximum permitted dividends as a percentage of "Adjusted net investment income"	100.00%
Maximum dividend permitted without affidavit	196,200,000
Statutory earned surplus, amount	205,500,000		180,500,000
Number of property and casualty subsidiaries	7
Europe, UK, and other
Statutory Accounting Practices [Line Items]
Required statutory capital and surplus	1,604,721,000		1,970,909,000
Actual statutory capital and surplus	2,712,552,000	[2]	2,684,317,000	[2]
Statutory net income (loss)	215,787,000		1,465,000		144,829,000
Ireland
Statutory Accounting Practices [Line Items]
Actual statutory capital and surplus	1,100,000,000
Distributable reserves, amount	2,900,000,000
United Kingdom
Statutory Accounting Practices [Line Items]
Actual statutory capital and surplus	$1,200,000,000

[1]	Required statutory capital and surplus at DecemberB 31, 2014 represents 100% Bermuda Solvency Capital Requirement (bBSCRb) level for the top Bermuda operating subsidiary, XL Insurance (Bermuda) Ltd, calculated on a consolidated basis (and therefore includes a BSCR requirement for all regions).
[2]	Statutory assets in Bermuda include investments in other U.S. and international subsidiaries reported separately herein.
[3]	Required statutory capital and surplus represents 100% Risk-Based Capital level for principal U.S. operating subsidiaries.

Computation_of_Earnings_Per_Or2

Computation of Earnings Per Ordinary Share and Ordinary Share Equivalent - Computation of basic and diluted earnings per share (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Basic earnings per ordinary share and ordinary share equivalents:
Net income (loss) attributable to ordinary shareholders									$188,340	$1,059,916	$651,128
Weighted average ordinary shares outstanding									267,103	287,801	307,372
Basic earnings per ordinary share & ordinary share equivalents outstanding (in Dollars per share)	$0.54	$0.27	($1.03)	$0.93	$1.07	$0.48	$0.94	$1.19	$0.71	$3.68	$2.12
Diluted earnings per ordinary share and ordinary share equivalents:
Weighted average ordinary shares outstanding									267,103	287,801	307,372
Impact of share based compensation and certain conversion features									4,424	4,268	2,910
Weighted average ordinary shares outstanding - diluted									271,527	292,069	310,282
Diluted earnings per ordinary share & ordinary share equivalents outstanding (in Dollars per share)	$0.53	$0.27	($1.03)	$0.91	$1.05	$0.47	$0.93	$1.17	$0.69	$3.63	$2.10
Dividends per share paid on ordinary shares									$0.64	$0.56	$0.44

Computation_of_Earnings_Per_Or3

Computation of Earnings Per Ordinary Share and Ordinary Share Equivalent - Narrative (Details) (Stock Compensation Plan Member)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Compensation Plan Member
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	5.5	6	8.7

Related_Party_Transactions_Sch

Related Party Transactions - Schedule of related party transactions activity (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	management_company	management_company	Dec. 31, 2012
Related Party Transaction [Line Items]
Reported net premiums written	$5,944,841	$6,199,404	$6,281,451
Net losses and loss expenses incurred	3,258,393	3,731,464	3,765,482
Reported acquisition costs	738,118	909,323	913,492
Number of investment management companies	6	5
Other strategic affiliates or subsidiaries
Related Party Transaction [Line Items]
Reported net premiums written	91,261	73,085	61,146
Net losses and loss expenses incurred	38,927	29,042	37,664
Reported acquisition costs	$35,711	$25,275	$24,014

Unaudited_Quarterly_Financial_2

Unaudited Quarterly Financial Data (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Interim Reporting [Line Items]
Net premiums earned									$5,895,070	$6,309,521	$6,090,437
Underwriting profit (loss)									585,907	245,191	3,968
Net income (loss) attributable to ordinary shareholders	139,500	72,384	-279,261	255,717	300,780	135,648	272,698	350,790
Earnings (loss) per ordinary share and ordinary share equivalent - basic (in dollars per share)	$0.54	$0.27	($1.03)	$0.93	$1.07	$0.48	$0.94	$1.19	$0.71	$3.68	$2.12
Earnings (loss) per ordinary share and ordinary share equivalent - diluted (in dollars per share)	$0.53	$0.27	($1.03)	$0.91	$1.05	$0.47	$0.93	$1.17	$0.69	$3.63	$2.10
Operating Segments [Member] \| Property and casualty operations
Interim Reporting [Line Items]
Net premiums earned	1,413,161	1,453,673	1,438,076	1,412,528	1,510,727	1,550,629	1,488,497	1,464,246	5,717,438	6,014,099	5,765,978
Underwriting profit (loss)	218,851	144,375	167,946	144,874	101,450	76,900	92,124	180,588	676,046	451,062	216,132
Corporate and other
Interim Reporting [Line Items]
Net premiums earned	$23,064	$19,739	$58,518	$76,311	$81,398	$74,683	$73,896	$65,445

Subsequent_Events_Details

Subsequent Events (Details)	Dec. 31, 2014	Dec. 31, 2013	Jan. 08, 2015	Jan. 08, 2015	Jan. 08, 2015	Dec. 15, 2014	Dec. 31, 2014
	USD ($)	USD ($)	Subsequent Event [Member]	Catlin Group Limited [Member]	Catlin Group Limited [Member]	ARX Holding Corporation [Member]	ARX Holding Corporation [Member]
				Subsequent Event [Member]	Subsequent Event [Member]	USD ($)	USD ($)
				USD ($)	GBP (£)
Subsequent Event [Line Items]
Business Acquisition Cash Price Per Share					£ 3.88
Business Acquisition In Kind Share Conversion Ratio			0.13
Ordinary shares, par value (in dollars per share)	$0.01	$0.01
Share Price				$35.42
Approximate Value Per Share Acquiree					£ 6.93
Business Combination Purchase Agreement Aggregate Purchase Price				$4,100,000,000
Term of credit facility				364 days	364 days
Available letter of credit facilities - commitments					1,600,000,000
Ownership percentage remaining							40.00%
Investments in affiliates							204,400,000
Expected proceeds on sale of affiliate						$500,000,000

Schedule_I_Consolidated_Summar1

Schedule I - Consolidated Summary of Investments - other than Investments in Related Parties (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	$29,753,876	[1]	$32,278,550	[1]
Fair Value	31,733,663		33,295,278
Amount Presented in the Balance Sheet	31,733,663		33,019,986
Other investments
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	1,002,871	[1]	949,310	[1]
Fair Value	1,248,439		1,167,382
Amount Presented in the Balance Sheet	1,248,439		1,164,630
Trading \| Life Funds Withheld Assets [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	1,180	[1]	0	[1]
Fair Value	1,171		0
Amount Presented in the Balance Sheet	1,171		0
Trading \| Life Funds Withheld Assets [Member] \| Corporate
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	1,180	[1]	0	[1]
Fair Value	1,171		0
Amount Presented in the Balance Sheet	1,171		0
AFS
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	28,749,825	[1]	28,470,545	[1]
Fair Value	30,484,053		28,996,661
Amount Presented in the Balance Sheet	30,484,053		28,996,661
AFS \| Exclude Life Funds Withheld Assets [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	24,448,486	[1]	28,470,545	[1]
Fair Value	25,302,488		28,996,661
Amount Presented in the Balance Sheet	25,302,488		28,996,661
AFS \| Exclude Life Funds Withheld Assets [Member] \| Fixed maturities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	23,427,432	[1]	27,111,874	[1]
Fair Value	24,177,469		27,500,136
Amount Presented in the Balance Sheet	24,177,469		27,500,136
AFS \| Exclude Life Funds Withheld Assets [Member] \| U.S. Government and Government - Related/Supported [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	2,100,851	[1]	2,484,193	[1]
Fair Value	2,171,953		2,501,851
Amount Presented in the Balance Sheet	2,171,953		2,501,851
AFS \| Exclude Life Funds Withheld Assets [Member] \| Corporate
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	8,462,130	[1]	10,802,332	[1]
Fair Value	8,778,373		11,125,830
Amount Presented in the Balance Sheet	8,778,373		11,125,830
AFS \| Exclude Life Funds Withheld Assets [Member] \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	3,625,171	[1]	3,540,101	[1]
Fair Value	3,728,576		3,546,122
Amount Presented in the Balance Sheet	3,728,576		3,546,122
AFS \| Exclude Life Funds Withheld Assets [Member] \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	404,398	[1]	396,798	[1]
Fair Value	427,351		398,768
Amount Presented in the Balance Sheet	427,351		398,768
AFS \| Exclude Life Funds Withheld Assets [Member] \| Commercial mortgage-backed securities ('CMBS') [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	1,033,819	[1]	1,223,313	[1]
Fair Value	1,052,544		1,246,795
Amount Presented in the Balance Sheet	1,052,544		1,246,795
AFS \| Exclude Life Funds Withheld Assets [Member] \| Collateralized debt obligations ('CDO') [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	717,544	[1]	754,414	[1]
Fair Value	692,034		717,313
Amount Presented in the Balance Sheet	692,034		717,313
AFS \| Exclude Life Funds Withheld Assets [Member] \| Other asset-backed securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	1,028,528	[1]	1,210,384	[1]
Fair Value	1,065,293		1,242,104
Amount Presented in the Balance Sheet	1,065,293		1,242,104
AFS \| Exclude Life Funds Withheld Assets [Member] \| U.S. States and political subdivisions of the States [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	1,892,566	[1]	1,821,499	[1]
Fair Value	2,021,272		1,845,812
Amount Presented in the Balance Sheet	2,021,272		1,845,812
AFS \| Exclude Life Funds Withheld Assets [Member] \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	4,162,425	[1]	4,878,840	[1]
Fair Value	4,240,073		4,875,541
Amount Presented in the Balance Sheet	4,240,073		4,875,541
AFS \| Exclude Life Funds Withheld Assets [Member] \| Equity securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	763,833	[1]	903,201	[1]
Fair Value	868,292		1,040,237
Amount Presented in the Balance Sheet	868,292		1,040,237
AFS \| Exclude Life Funds Withheld Assets [Member] \| Short-term investments
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	257,221	[1]	455,470	[1]
Fair Value	256,727		456,288
Amount Presented in the Balance Sheet	256,727		456,288
AFS \| Life Funds Withheld Assets [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	4,301,339	[1]	0	[1]
Fair Value	5,181,565		0
Amount Presented in the Balance Sheet	5,181,565		0
AFS \| Life Funds Withheld Assets [Member] \| U.S. Government and Government - Related/Supported [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	14,866	[1]	0	[1]
Fair Value	18,724		0
Amount Presented in the Balance Sheet	18,724		0
AFS \| Life Funds Withheld Assets [Member] \| Corporate
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	2,407,849	[1]	0	[1]
Fair Value	2,817,980		0
Amount Presented in the Balance Sheet	2,817,980		0
AFS \| Life Funds Withheld Assets [Member] \| Residential mortgage-backed securities - Agency ('RMBS - Agency') [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	3,301	[1]	0	[1]
Fair Value	3,782		0
Amount Presented in the Balance Sheet	3,782		0
AFS \| Life Funds Withheld Assets [Member] \| Residential mortgage-backed securities - Non-Agency ('RMBS - Non-Agency') [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	71,075	[1]	0	[1]
Fair Value	85,335		0
Amount Presented in the Balance Sheet	85,335		0
AFS \| Life Funds Withheld Assets [Member] \| Commercial mortgage-backed securities ('CMBS') [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	168,886	[1]	0	[1]
Fair Value	193,167		0
Amount Presented in the Balance Sheet	193,167		0
AFS \| Life Funds Withheld Assets [Member] \| Other asset-backed securities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	238,168	[1]	0	[1]
Fair Value	273,541		0
Amount Presented in the Balance Sheet	273,541		0
AFS \| Life Funds Withheld Assets [Member] \| Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	1,397,194	[1]	0	[1]
Fair Value	1,789,036		0
Amount Presented in the Balance Sheet	1,789,036		0
HTM \| Fixed maturities
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Cost or Amortized Cost	0	[1]	2,858,695	[1]
Fair Value	0		3,131,235
Amount Presented in the Balance Sheet	$0		$2,858,695

[1]	Investments in fixed maturities, short-term investments and held to maturity are shown at amortized cost.

Schedule_II_Condensed_Financia1

Schedule II - Condensed Financial Information of Registrant - Condensed Balance Sheets (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
ASSETS
Cash and cash equivalents	$2,521,814	$1,800,832	$2,618,378	$3,825,125
Other assets	750,872	693,810
Total assets	45,046,819	45,652,887
Liabilities:
Total liabilities	33,611,052	34,303,589
Commitments and Contingencies
Shareholders' equity:
Ordinary shares, 999,990,000 authorized, par value $0.01; issued and outstanding (2014, 255,182,955; 2013, 278,253,308)	2,552	2,783
Additional paid in capital	7,359,102	7,994,100
Accumulated other comprehensive income	1,484,458	736,657	1,520,020	583,065
Retained earnings	1,187,640	1,264,093
Shareholders' equity attributable to XL Group plc	10,033,752	9,997,633
Total liabilities and shareholders' equity	45,046,819	45,652,887
Parenthetical information:
Ordinary shares, shares authorized (in shares)	999,990,000	999,990,000
Ordinary shares, par value (in dollars per share)	$0.01	$0.01
Ordinary shares, shares issued (in shares)	255,182,955	278,253,308
Ordinary shares, shares outstanding (in shares)	255,182,955	278,253,308	298,682,000
XL Group PLC
ASSETS
Cash and cash equivalents	22,443	12,709	10,961	1,644
Investments in subsidiaries on an equity basis	10,195,445	10,187,614
Other assets	3,017	3,014
Total assets	10,220,905	10,203,337
Liabilities:
Amounts due to subsidiaries	166,782	190,601
Accounts payable and accrued liabilities	20,371	15,103
Total liabilities	187,153	205,704
Commitments and Contingencies
Shareholders' equity:
Ordinary shares, 999,990,000 authorized, par value $0.01; issued and outstanding (2014, 255,182,955; 2013, 278,253,308)	2,552	2,783
Additional paid in capital	7,359,102	7,994,100
Accumulated other comprehensive income	1,484,458	736,657
Retained earnings	1,187,640	1,264,093
Shareholders' equity attributable to XL Group plc	10,033,752	9,997,633
Total liabilities and shareholders' equity	$10,220,905	$10,203,337
Parenthetical information:
Ordinary shares, shares authorized (in shares)	999,990,000	999,990,000
Ordinary shares, par value (in dollars per share)	$0.01	$0.01
Ordinary shares, shares issued (in shares)	255,182,955	278,253,308
Ordinary shares, shares outstanding (in shares)	255,182,955	278,253,308

Schedule_II_Condensed_Financia2

Schedule II - Condensed Financial Information of Registrant - Statement of Income and Comprehensive Income (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements Captions [Line Items]
Net investment income									$918,625,000	$957,716,000	$1,012,348,000
Total revenues									6,602,267,000	7,541,234,000	7,232,397,000
Operating expenses									1,341,315,000	1,213,178,000	1,173,955,000
Foreign exchange (gains) losses									-37,568,000	-28,243,000	10,545,000
Interest expense									134,106,000	155,462,000	172,204,000
Total expenses									6,343,750,000	6,446,886,000	6,521,873,000
Provision for income tax									-96,897,000	-77,505,000	-34,028,000
Net income (loss) attributable to ordinary shareholders									188,340,000	1,059,916,000	651,128,000
Net income (loss)	139,500,000	72,384,000	-279,261,000	255,717,000	300,780,000	135,648,000	272,698,000	350,790,000
Unrealized gains on held to maturity investment portfolio at time of transfer to available for sale, net of tax									424,861,000	0	0
Cumulative adjustments recorded to value of future policy benefit reserves, amount									-400,456,000	-44,660,000	0
Change in net unrealized gains (losses) on affiliate and other investments, net of tax									35,143,000	26,637,000	46,162,000
Change in OTTI losses recognized in other comprehensive income, net of tax									13,143,000	32,181,000	67,280,000
Change in underfunded pension liability									-7,550,000	7,653,000	-3,371,000
Change in value of cash flow hedge									255,000	439,000	439,000
Foreign currency translation adjustments									-25,729,000	-54,858,000	-8,156,000
Comprehensive income (loss)									936,141,000	276,553,000	1,588,083,000
XL Group PLC
Condensed Financial Statements Captions [Line Items]
Net investment income									275,000	24,000	5,000
Total revenues									275,000	24,000	5,000
Operating expenses									9,646,000	11,699,000	10,971,000
Foreign exchange (gains) losses									127,000	243,000	165,000
Interest expense									5,000	2,000	15,000
Total expenses									9,778,000	11,944,000	11,151,000
Income (loss) before income tax									-9,503,000	-11,920,000	-11,146,000
Equity in net earnings (losses) of subsidiaries (dividends were: 2014: $858,521; 2013: $617,719; 2012: nil)									197,843,000	1,071,836,000	662,274,000
Net income (loss) attributable to ordinary shareholders									188,340,000	1,059,916,000	651,128,000
Net income (loss)									188,340,000	1,059,916,000	651,128,000
Unrealized gains on held to maturity investment portfolio at time of transfer to available for sale, net of tax									424,861,000	0	0
Change in net unrealized gains (losses) on affiliate and other investments, net of tax									35,143,000	26,637,000	46,162,000
Change in OTTI losses recognized in other comprehensive income, net of tax									13,143,000	32,181,000	67,280,000
Change in underfunded pension liability									-7,550,000	7,653,000	-3,371,000
Change in value of cash flow hedge									255,000	439,000	439,000
Foreign currency translation adjustments									-25,729,000	-54,858,000	-8,156,000
Comprehensive income (loss)									936,141,000	276,553,000	1,588,083,000
Parenthetical information, dividends:
Dividends received from subsidiaries									858,521,000	617,719,000	0
Dividends and Return of Capital Received From Subsidiary									940,000,000	702,000,000	342,000,000
Life Funds Withheld Assets [Member]
Condensed Financial Statements Captions [Line Items]
Net investment income									129,575,000	0	0
Change in net unrealized gains (losses) on investments, net of tax									274,083,000	0	0
Life Funds Withheld Assets [Member] \| XL Group PLC
Condensed Financial Statements Captions [Line Items]
Change in net unrealized gains (losses) on investments, net of tax									274,083,000	0	0
Exclude Life Funds Withheld Assets [Member]
Condensed Financial Statements Captions [Line Items]
Net investment income									789,050,000	957,716,000	1,012,348,000
Change in net unrealized gains (losses) on investments, net of tax									434,051,000	-750,755,000	834,601,000
Exclude Life Funds Withheld Assets [Member] \| XL Group PLC
Condensed Financial Statements Captions [Line Items]
Change in net unrealized gains (losses) on investments, net of tax									434,051,000	-750,755,000	834,601,000
Unrealized Gains (Losses) on Investments
Condensed Financial Statements Captions [Line Items]
Provision for income tax									-1,593,000	5,183,000
Cumulative adjustments recorded to value of future policy benefit reserves, amount									-400,456,000
Unrealized Gains (Losses) on Investments \| XL Group PLC
Condensed Financial Statements Captions [Line Items]
Cumulative adjustments recorded to value of future policy benefit reserves, amount									($400,456,000)	($44,660,000)	$0

Schedule_II_Condensed_Financia3

Schedule II - Condensed Financial Information of Registrant - Statement of Cash Flows (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements Captions [Line Items]
Net income (loss) attributable to ordinary shareholders	$188,340	$1,059,916	$651,128
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Share based compensation	81,287	46,489	47,472
Other	5,447	9,702	-58,249
Total adjustments	694,346	-356,670	325,723
Net cash provided by (used in) operating activities	963,184	779,977	1,056,106
Cash flows provided by (used in) investing activities: [Abstract]
Net cash provided by (used in) investing activities	1,711,621	-1,197,862	-942,593
Cash flows provided by (used in) financing activities:
Proceeds from issuance of ordinary shares and exercise of stock options	6,367	12,623	5,413
Dividends paid	-169,620	-160,155	-134,799
Buybacks of ordinary shares	-801,953	-675,617	-402,930
Net cash provided by (used in) financing activities	-1,863,708	-394,843	-1,344,753
Net change in cash and cash equivalents	720,982	-817,546	-1,206,747
Cash and cash equivalents b beginning of period	1,800,832	2,618,378	3,825,125
Cash and cash equivalents b end of period	2,521,814	1,800,832	2,618,378
XL Group PLC
Condensed Financial Statements Captions [Line Items]
Net income (loss) attributable to ordinary shareholders	188,340	1,059,916	651,128
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity in (earnings) loss of subsidiaries	-197,843	-1,071,836	-662,274
Share based compensation	81,287	46,489	47,472
Amount due to (from) subsidiaries	-23,819	104,590	166,853
Dividends received from subsidiaries	858,521	617,719	0
Other	-10,632	-16,570	-3,296
Total adjustments	707,514	-319,608	-451,245
Net cash provided by (used in) operating activities	895,854	740,308	199,883
Cash flows provided by (used in) investing activities: [Abstract]
Returns of capital from subsidiaries	79,086	84,589	341,750
Net cash provided by (used in) investing activities	79,086	84,589	341,750
Cash flows provided by (used in) financing activities:
Proceeds from issuance of ordinary shares and exercise of stock options	6,367	12,623	5,413
Dividends paid	-169,620	-160,155	-134,799
Buybacks of ordinary shares	-801,953	-675,617	-402,930
Net cash provided by (used in) financing activities	-965,206	-823,149	-532,316
Net change in cash and cash equivalents	9,734	1,748	9,317
Cash and cash equivalents b beginning of period	12,709	10,961	1,644
Cash and cash equivalents b end of period	$22,443	$12,709	$10,961

Schedule_IV_Reinsurance_Detail

Schedule IV - Reinsurance (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Life reinsurance in force:
Gross amount, life reinsurance in force	$0	[1]	$0	[1]	$0	[1]
Ceded to other companies, life reinsurance in force	46,947,677	[1]	378,391	[1]	443,798	[1]
Assumed from other companies, life reinsurance in force	68,854,340	[1]	77,917,632	[1]	82,099,647	[1]
Net amount, life reinsurance in force	21,906,663	[1]	77,539,241	[1]	81,655,849	[1]
Percentage of amount assumed to net, life reinsurance in force	314.30%	[1]	100.50%	[1]	100.50%	[1]
Total premiums earned:
Gross amount, premiums earned	5,173,403		4,966,207		4,604,323
Ceded to other companies, premiums earned	1,955,098		1,344,289		1,263,157
Assumed from other companies, premiums earned	2,676,765		2,687,603		2,749,271
Net amount, premiums earned	5,895,070		6,309,521		6,090,437
Percentage of amount assumed to net	45.40%		42.60%		45.10%
Property and casualty operations
Total premiums earned:
Gross amount, premiums earned	5,173,403		4,966,207		4,604,323
Ceded to other companies, premiums earned	1,799,294		1,315,369		1,231,835
Assumed from other companies, premiums earned	2,343,329		2,363,261		2,393,490
Net amount, premiums earned	5,717,438		6,014,099		5,765,978
Percentage of amount assumed to net	41.00%		39.30%		41.50%
Life operations
Total premiums earned:
Gross amount, premiums earned	0		0		0
Ceded to other companies, premiums earned	155,804		28,920		31,322
Assumed from other companies, premiums earned	333,436		324,342		355,781
Net amount, premiums earned	$177,632		$295,422		$324,459
Percentage of amount assumed to net	187.70%		109.80%		109.70%

[1]	Represents the sum face value outstanding of the in force life reinsurance policies.

Schedule_VI_Supplementary_Info1

Schedule VI - Supplementary Information Concerning Property/Casualty Insurance Operations (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Losses and loss expenses incurred related to - current year	$3,513,469	$4,021,353	$4,081,376
Losses and loss expenses incurred related to - prior year	-255,076	-289,889	-315,894
P&C Operations
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Deferred acquisition costs	357,067	537,473	536,664
Reserves for losses and loss expenses	19,353,241	20,481,065	20,484,121
Reserves for unearned premiums	3,973,159	3,846,568	3,755,117
Net earned premiums	5,717,438	6,014,099	5,765,978
Net investment income	642,492	671,071	712,905
Losses and loss expenses incurred related to - current year	3,513,469	4,021,353	4,081,376
Losses and loss expenses incurred related to - prior year	-255,076	-289,889	-315,894
Net paid losses and loss expenses	3,821,335	3,828,139	3,783,242
Amortization of deferred acquisition costs	724,003	882,658	872,399
Net premiums written	$5,767,209	$5,903,982	$5,957,019

Uncategorized_Items

Uncategorized Items
[us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest]	736,657,000