Jefferies Financial (JEF) 10-Q 8 May 15 2015 Q1 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 23, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	-19
Entity Central Index Key	96223
Entity Registrant Name	LEUCADIA NATIONAL CORP
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		366,658,918

Consolidated_Statements_Of_Fin

Consolidated Statements Of Financial Condition (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
ASSETS
Cash and cash equivalents	$3,524,524		$4,276,775
Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations	3,186,319	[1]	3,444,674	[1]
Financial instruments owned, including securities pledged of $14,407,276 and $14,794,488:
Trading assets, at fair value	20,971,087		19,612,490
Available for sale securities	974,430		1,608,769
Total financial instruments owned	21,945,517		21,221,259
Investments in managed funds	593,581		281,470
Loans to and investments in associated companies	1,762,711		1,712,568
Securities borrowed	6,566,376		6,853,103
Securities purchased under agreements to resell	3,745,688		3,926,858
Securities received as collateral	4,821		5,418
Receivables	4,354,707		3,934,825
Property, equipment and leasehold improvements, net	722,149		726,376
Intangible assets, net and goodwill	2,702,298		2,720,763
Deferred tax asset, net	1,506,968		1,712,535
Other assets	1,707,033		1,807,284
Total	52,322,692		52,623,908
LIABILITIES
Short-term borrowings	411,998		12,000
Trading liabilities, at fair value	7,945,501		8,904,592
Securities loaned	3,173,512		2,598,487
Securities sold under agreements to repurchase	11,323,367		10,672,157
Other secured financings	950,377		705,126
Obligation to return securities received as collateral	4,821		5,418
Payables, expense accruals and other liabilities	8,940,421		10,516,491
Long-term debt	8,558,783		8,527,929
Total liabilities	41,308,780		41,942,200
Commitments and contingencies
MEZZANINE EQUITY
Redeemable noncontrolling interests	168,541		186,686
Mandatorily redeemable convertible preferred shares	125,000		125,000
EQUITY
Common shares, par value $1 per share, authorized 600,000,000 shares; 366,721,455 and 367,498,615 shares issued and outstanding, after deducting 49,224,733 and 48,447,573 shares held in treasury	366,721		367,499
Additional paid-in capital	5,073,033		5,059,508
Accumulated other comprehensive income	427,118		447,082
Retained earnings	4,784,966		4,428,069
Total Leucadia National Corporation shareholders' equity	10,651,838		10,302,158
Noncontrolling interests	68,533		67,864
Total equity	10,720,371		10,370,022
Total	$52,322,692		$52,623,908
[1]	Securities comprise U.S. government securities segregated for regulatory purposes with a fair value of $434.8 million and $453.7 million at March 31, 2015 and December 31, 2014, respectively, and Commodities Futures Trading Commission ("CFTC") approved money market funds with a fair value of $810.0 million and $545.0 million at March 31, 2015 and December 31, 2014, respectively.

Consolidated_Statements_Of_Fin1

Consolidated Statements Of Financial Condition (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
ASSETS
Securities pledged	$14,407,276	$14,794,488
EQUITY
Common shares, par value	$1	$1
Common shares, authorized (actual number)	600,000,000	600,000,000
Common shares, issued and outstanding after deducting shares held in treasury (actual number)	366,721,455	367,498,615
Treasury stock, shares (actual number)	49,224,733	48,447,573

Consolidated_Statements_Of_Ope

Consolidated Statements Of Operations (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Revenues:
Beef processing services	$1,852,311	$1,885,754
Commissions	166,922	162,063
Principal transactions	729,235	281,054
Investment banking	250,995	414,320
Interest income	237,599	257,660
Net realized securities gains	15,089	5,394
Other	124,370	132,832
Total revenues	3,376,521	3,139,077
Net revenues	3,184,683	2,942,524
Expenses:
Cost of sales	1,922,223	1,945,675
Compensation and benefits	410,852	565,837
Floor brokerage and clearing fees	55,080	49,570
Interest	30,449	28,576
Depreciation and amortization	52,440	41,487
Selling, general and other expenses	166,983	174,319
Total expenses	2,638,027	2,805,464
Income from continuing operations before income taxes and income related to associated companies	546,656	137,060
Income related to associated companies	40,451	20,036
Income from continuing operations before income taxes	587,107	157,096
Income tax provision	212,678	56,250
Income from continuing operations	374,429	100,846
Loss from discontinued operations, net of income tax (benefit) of $0 and $(4,796)		-8,909
Net income	374,429	91,937
Net (income) loss attributable to the noncontrolling interests	234	-2,537
Net loss attributable to the redeemable noncontrolling interests	7,112	5,932
Preferred stock dividends	-1,016	-1,016
Net income attributable to Leucadia National Corporation common shareholders	380,759	94,316
Basic earnings (loss) per common share attributable to Leucadia National Corporation common shareholders:
Income from continuing operations	$1	$0.27
Loss from discontinued operations		($0.02)
Net income	$1	$0.25
Diluted earnings (loss) per common share attributable to Leucadia National Corporation common shareholders:
Income from continuing operations	$0.99	$0.27
Loss from discontinued operations		($0.02)
Net income	$0.99	$0.25
Amounts attributable to Leucadia National Corporation common shareholders:
Income from continuing operations, net of taxes	380,759	103,205
Loss from discontinued operations, net of taxes		-8,889
Net income attributable to Leucadia National Corporation common shareholders	380,759	94,316
Investment Banking And Capital Markets Segment [Member]
Expenses:
Interest	$191,838	$196,553

Consolidated_Statements_Of_Ope1

Consolidated Statements Of Operations (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Consolidated Statements Of Operations [Abstract]
Income tax (benefit) related to discontinued operations	$0	($4,796)

Consolidated_Statements_Of_Com

Consolidated Statements Of Comprehensive Income (Loss) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Consolidated Statements Of Comprehensive Income (Loss) [Abstract]
Net income	$374,429	$91,937
Other comprehensive income (loss):
Net unrealized holding gains (losses) on investments arising during the period, net of income tax provision (benefit) of $(619) and $2,393	-1,115	4,310
Less: reclassification adjustment for net (gains) losses included in net income (loss), net of income tax provision (benefit) of $2,944 and $(488)	-5,303	878
Net change in unrealized holding gains (losses) on investments, net of income tax provision (benefit) of $(3,563) and $2,881	-6,418	5,188
Net unrealized foreign exchange gains (losses) arising during the period, net of income tax provision (benefit) of $(5,768) and $62	-14,721	13,897
Less: reclassification adjustment for foreign exchange (gains) losses included in net income (loss), net of income tax provision (benefit) of $0 and $0
Net change in unrealized foreign exchange gains (losses), net of income tax provision (benefit) of $(5,768) and $62	-14,721	13,897
Net unrealized gains (losses) on derivatives arising during the period, net of income tax provision (benefit) of $0 and $92		165
Less: reclassification adjustment for derivative (gains) losses included in net income (loss), net of income tax provision (benefit) of $0 and $0
Net change in unrealized derivative gains (losses), net of income tax provision (benefit) of $0 and $92		165
Net pension gains (losses) arising during the period, net of income tax provision (benefit) of $0 and $0
Less: reclassification adjustment for pension (gains) losses included in net income (loss), net of income tax provision (benefit) of $(653) and $(422)	1,175	760
Net change in pension liability, net of income tax provision (benefit) of $653 and $422	1,175	760
Other comprehensive income (loss), net of income taxes	-19,964	20,010
Comprehensive income	354,465	111,947
Comprehensive (income) loss attributable to the noncontrolling interests	234	-2,537
Comprehensive loss attributable to the redeemable noncontrolling interests	7,112	5,932
Preferred stock dividends	-1,016	-1,016
Comprehensive income attributable to Leucadia National Corporation common shareholders	$360,795	$114,326

Consolidated_Statements_Of_Com1

Consolidated Statements Of Comprehensive Income (Loss) (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Consolidated Statements Of Comprehensive Income (Loss) [Abstract]
Net unrealized holding gains (losses) on investments arising during the period, tax provision (benefit)	($619)	$2,393
Less: reclassification adjustment for net (gains) losses included in net income (loss), tax provision (benefit)	2,944	-488
Net change in unrealized holding gains (losses) on investments, tax provision (benefit)	-3,563	2,881
Net unrealized foreign exchange gains (losses) arising during the period, tax provision (benefit)	-5,768	62
Less: reclassification adjustment for foreign exchange (gains) losses included in net income (loss), tax provision (benefit)	0	0
Net change in unrealized foreign exchange gains (losses), tax provision (benefit)	-5,768	62
Net unrealized gains (losses) on derivatives arising during the period, tax provision (benefit)	0	92
Less: reclassification adjustment for derivative (gains) losses included in net income (loss), tax provision (benefit)	0	0
Net change in unrealized derivative gains (losses), tax provision (benefit)	0	92
Net pension gains (losses) arising during the period, tax provision (benefit)	0	0
Less: reclassification adjustment for pension (gains) losses included in net income (loss), tax provision (benefit)	-653	-422
Net change in pension liability, tax provision (benefit)	$653	$422

Consolidated_Statements_Of_Cas

Consolidated Statements Of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Net cash flows from operating activities:
Net income	$374,429	$91,937
Adjustments to reconcile net income to net cash used for operations:
Deferred income tax provision	214,612	39,754
Depreciation and amortization of property, equipment and leasehold improvements	37,262	29,336
Other amortization	3,066	-265
Share-based compensation	32,794	38,207
Provision for doubtful accounts	3,636	2,752
Net securities gains	-15,089	-5,394
Income related to associated companies	-61,140	-40,663
Distributions from associated companies	39,703	20,912
Net gains related to property and equipment, and other assets	-659	-1,177
Net change in:
Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations	257,319	-183,710
Trading assets	-1,095,937	-1,968,227
Investments in managed funds	-312,111	-4,978
Securities borrowed	285,891	-756,481
Securities purchased under agreements to resell	179,290	-694,175
Receivables from brokers, dealers and clearing organizations	-38,561	-478,066
Receivables from customers of securities operations	-94,841	-227,813
Other receivables	-28,557	-72,241
Other assets	-124,643	-149,111
Trading liabilities	-966,190	2,282,870
Securities loaned	575,750	572,285
Securities sold under agreements to repurchase	654,705	-10,772
Payables to brokers, dealers and clearing organizations	384,163	287,356
Payables to customers of securities operations	-1,481,640	488,178
Trade payables, expense accruals and other liabilities	-487,782	-294,047
Other	-62,857	-946
Net cash used for operating activities	-1,727,387	-1,034,479
Net cash flows from investing activities:
Acquisitions of property, equipment and leasehold improvements, and other assets	-62,821	-75,057
Proceeds from disposals of property and equipment, and other assets	3,103	2,681
Acquisitions, net of cash acquired		-10,178
Cash paid and cash of real estate operations sold to HomeFed Corporation		-18,100
Advances on notes and other receivables	-283,000
Collections on notes, loans and other receivables	21,836	4,432
Loans to and investments in associated companies	-607,025	-794,498
Capital distributions and loan repayment from associated companies	560,043	780,503
Deconsolidation of asset management entities		-207,965
Purchases of investments (other than short-term)	-400,484	-402,451
Proceeds from maturities of investments	139,988	282,760
Proceeds from sales of investments	897,246	1,007,243
Other	-966	-1,883
Net cash provided by investing activities	267,920	567,487
Net cash flows from financing activities:
Issuance of debt, net of issuance costs	127,486	192,690
Change in short-term borrowings	399,998
Reduction of debt	-15,448	-21,930
Net proceeds from other secured financings	245,251	35,683
Issuance of common shares	616	592
Distributions to noncontrolling interests		-778
Contributions from noncontrolling interests	533	8,604
Purchase of common shares for treasury	-27,010	-46,710
Dividends paid	-23,359	-23,186
Other	246	953
Net cash provided by financing activities	708,313	145,918
Effect of foreign exchange rate changes on cash	-1,097	4,006
Net decrease in cash and cash equivalents	-752,251	-317,068
Cash and cash equivalents at January 1, including cash classified as assets of discontinued operations	4,276,775	3,907,595
Cash and cash equivalents at March 31, including cash classified as assets of discontinued operations	3,524,524	3,590,527
Supplemental disclosures of cash flow information:
Interest	204,769	266,179
Income tax payments (refunds), net	$828	($1,359)

Consolidated_Statements_Of_Cha

Consolidated Statements Of Changes In Equity (USD $)	Common Shares $1 Par Value [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Subtotal [Member]	Noncontrolling Interest [Member]	Total
In Thousands
Balance, at Dec. 31, 2013	$364,541	$4,881,031	$538,050	$4,318,840	$10,102,462	$70,591	$10,173,053
Net income				94,316	94,316	2,537	96,853
Other comprehensive income (loss), net of taxes			20,010		20,010		20,010
Contributions from noncontrolling interests						8,604	8,604
Distributions to noncontrolling interests						-778	-778
Deconsolidation of asset management entities						-77,475	-77,475
Change in fair value of redeemable noncontrolling interests		755			755		755
Issuance of common shares for debt conversion	1	11			12		12
Purchase of common shares for treasury	-1,714	-44,996			-46,710		-46,710
Share-based compensation expense		38,207			38,207		38,207
Dividends ($.0625 per common share)				-23,703	-23,703		-23,703
Other	1,137	1,297			2,434		2,434
Balance, at Mar. 31, 2014	363,965	4,876,305	558,060	4,389,453	10,187,783	3,479	10,191,262
Balance, at Dec. 31, 2014	367,499	5,059,508	447,082	4,428,069	10,302,158	67,864	10,370,022
Net income				380,759	380,759	-234	380,525
Other comprehensive income (loss), net of taxes			-19,964		-19,964		-19,964
Contributions from noncontrolling interests						533	533
Change in interest in consolidated subsidiary		-370			-370	370
Change in fair value of redeemable noncontrolling interests		11,033			11,033		11,033
Purchase of common shares for treasury	-1,182	-25,828			-27,010		-27,010
Share-based compensation expense		32,794			32,794		32,794
Dividends ($.0625 per common share)				-23,862	-23,862		-23,862
Other	404	-4,104			-3,700		-3,700
Balance, at Mar. 31, 2015	$366,721	$5,073,033	$427,118	$4,784,966	$10,651,838	$68,533	$10,720,371

Consolidated_Statements_Of_Cha1

Consolidated Statements Of Changes In Equity (Parenthetical) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Consolidated Statements Of Changes In Equity [Abstract]
Dividends per common share	$0.06	$0.06

Nature_Of_Operations

Nature Of Operations	3 Months Ended
	Mar. 31, 2015
Nature Of Operations [Abstract]
Nature Of Operations	1. Nature of Operations
	Leucadia National Corporation ("Leucadia" or the "Company") is a diversified holding company focused on return on investment and long-term value creation to maximize shareholder value. We continuously review acquisitions of businesses, securities and assets that have the potential for significant long-term value creation, invest in a broad array of businesses, and evaluate the retention and disposition of our existing operations and holdings. Changes in the mix of our businesses and investments should be expected.
	Our financial services businesses and investments include Jefferies (investment banking and capital markets), Leucadia Asset Management (asset management), FXCM (a publicly traded company providing online foreign exchange trading), HomeFed (a publicly traded real estate company), and Berkadia (commercial mortgage banking and servicing). We also own and have investments in a diverse array of other businesses, including National Beef (beef processing), HRG Group, formerly known as Harbinger (a publicly traded diversified holding company), Vitesse Energy and Juneau Energy (oil and gas exploration and development), Garcadia (automobile dealerships), Linkem (fixed wireless broadband services in Italy), Conwed Plastics and Idaho Timber (manufacturing companies), and Golden Queen (a gold and silver mining project). The structure of each of our investments is tailored to the unique opportunity each transaction presents. Our investments may be reflected in our consolidated results as operating subsidiaries, equity investments, receivables, securities, or in other ways, depending on the structure of our holdings.
	Jefferies is a global full service, integrated securities and investment banking firm. In March of 2013, Jefferies became an indirect wholly-owned subsidiary of Leucadia, yet retains a separate credit rating and continues to be a separate SEC reporting company. Through Jefferies, we own 50% of Jefferies Finance, our joint venture with Babson Capital Management LLC and Massachusetts Mutual Life Insurance Company. Jefferies Finance is a commercial finance company whose primary focus is the origination and syndication of senior secured debt of middle market and growth companies in the form of term and revolving loans. Through Jefferies, we also own a 48.5% voting interest in Jefferies LoanCore, a joint venture with the Government of Singapore Investment Corporation and LoanCore, LLC. Jefferies LoanCore originates and purchases commercial real estate loans throughout the United States.
	Jefferies has a November 30th fiscal year, which it retains for standalone reporting purposes. We reflect Jefferies in our consolidated financial statements utilizing a one month lag. We have reviewed Jefferies business and internal operating results for the month of March 2015 for the purpose of evaluating whether additional financial statement disclosure or adjustments are required to this Quarterly Report on Form 10-Q, and we have concluded that no additional disclosures or adjustments are warranted.
	Leucadia Asset Management seeds and develops focused funds managed by distinct management teams, each of which operates as a separate business unit.
	Our investment in FXCM consists of a $300 million two-year senior secured term loan ($287.6 million outstanding at March 31, 2015), with rights to a variable proportion of certain distributions in connection with an FXCM sale of assets or certain other events, and our right to require a sale of FXCM beginning in January 2018.
	Berkadia, our 50-50 joint venture with Berkshire Hathaway, originates and brokers commercial real estate loans under various programs and services commercial real estate loans in the U.S.
	We own approximately 65% of HomeFed, which owns and develops real estate projects. HomeFed is a public company traded on the NASD OTC Bulletin Board.
	We own 78.9% of National Beef Packing Company. National Beef processes and markets fresh boxed beef, case-ready beef, beef by-products and wet blue leather for domestic and international markets. National Beef operates two beef processing facilities, three consumer-ready facilities and a wet blue tanning facility, all located in the U.S. National Beef's products include boxed beef, ground beef, hides, tallow, and other beef and beef by-products. National Beef operates the largest wet blue tanning facility in the world that sells processed hides to tanners that produce finished leather for the automotive, luxury goods, apparel and furniture industries. National Beef owns Kansas City Steak Company, LLC, which sells portioned beef and other products to customers in the food service and retail channels as well as direct to consumers through the internet and direct mail. National Beef also owns a refrigerated and livestock transportation company that provides transportation services for National Beef and third parties.
	We own approximately 23% of HRG, a diversified holding company that operates in four business segments: consumer products, insurance, energy and asset management. HRG is a public company traded on the NYSE.
	Vitesse Energy, LLC acquires and develops non-operated working and royalty oil and gas interests in the Bakken Shale oil field in North Dakota.
	Juneau Energy, LLC engages in the exploration, development and production of oil and gas from onshore, unconventional resource areas. Juneau currently has interests in acreage in the Oklahoma and Texas Gulf Coast regions.
	Garcadia is a joint venture that owned and operated 26 automobile dealerships in the U.S. as of March 31, 2015.
	We own approximately 42% of the common shares of Linkem and a convertible note which, if converted, would increase our ownership to approximately 55% of Linkem's common shares. Linkem provides residential broadband services using Wimax and LTE technologies deployed over the 3.5 GHz spectrum band. Linkem operates in Italy, which has few cable television systems and poor broadband alternatives.
	Conwed Plastics manufactures and markets lightweight plastic netting used for building and construction, erosion and sediment control, packaging, agricultural purposes, carpet padding, filtration, consumer products and other purposes. Conwed Plastics has four domestic manufacturing facilities, and it owns and operates a manufacturing and sales facility in Belgium.
	Idaho Timber is engaged in the manufacture and/or distribution of various wood products, including the following principal product lines: remanufacturing dimension lumber; remanufacturing, bundling and bar coding of home center boards for large retailers; and production of pine dimension lumber and 5/4" radius-edge, pine decking. Idaho Timber operates ten facilities located in the U.S.
	Golden Queen Mining Company, LLC owns the Soledad Mountain project, a fully-permitted, open pit, heap leach gold and silver project in Kern County, California. We and the Clay family have formed and made contributions to a limited liability company, controlled by us, through which we invested in Golden Queen Mining Company, LLC for the development and operation of the project. Our effective ownership of Golden Queen Mining Company, LLC is approximately 34%.

Basis_Of_Presentation_And_Sign

Basis Of Presentation And Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
Basis Of Presentation And Significant Accounting Policies [Abstract]
Basis Of Presentation And Significant Accounting Policies	Note 2. Basis of Presentation and Significant Accounting Policies
	Our unaudited interim consolidated financial statements have been prepared in accordance with the instructions for Form 10-Q and, therefore, do not include all information and footnotes which are normally included in our Annual Report on Form 10-K. These financial statements reflect all adjustments (consisting of normal recurring items or items discussed herein) that management believes are necessary to fairly state results for the interim periods presented. Results of operations for interim periods are not necessarily indicative of annual results of operations.
	The preparation of these financial statements in accordance with accounting principles generally accepted in the United States of America ("GAAP") requires us to make estimates and assumptions that affect the reported amounts in the financial statements and disclosures of contingent assets and liabilities. On an on-going basis, we evaluate all of these estimates and assumptions. The most important of these estimates and assumptions relate to fair value measurements, compensation and benefits, asset impairment, the ability to realize deferred tax assets, the recognition and measurement of uncertain tax positions and contingencies. Although these and other estimates and assumptions are based on the best available information, actual results could be different from these estimates.
	Fair Value Hierarchy
	In determining fair value, we maximize the use of observable inputs and minimize the use of unobservable inputs by requiring that observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from independent sources. Unobservable inputs reflect our assumptions that market participants would use in pricing the asset or liability developed based on the best information available in the circumstances. We apply a hierarchy to categorize our fair value measurements broken down into three levels based on the transparency of inputs as follows:
	Level 1:	Quoted prices are available in active markets for identical assets or liabilities as of the reported date.
	Level 2:	Pricing inputs are other than quoted prices in active markets, which are either directly or indirectly observable as of the reported date. The nature of these financial instruments include cash instruments for which quoted prices are available but traded less frequently, derivative instruments whose fair value have been derived using a model where inputs to the model are directly observable in the market, or can be derived principally from or corroborated by observable market data, and instruments that are fair valued using other financial instruments, the parameters of which can be directly observed.
	Level 3:	Instruments that have little to no pricing observability as of the reported date.	These financial instruments are
		measured using management's best estimate of fair value, where the inputs into the determination of fair value
		require significant management judgment or estimation.
	Financial instruments are valued at quoted market prices, if available. Certain financial instruments have bid and ask prices that can be observed in the marketplace. For financial instruments whose inputs are based on bid-ask prices, the financial instrument is valued at the point within the bid-ask range that meets our best estimate of fair value. We use prices and inputs that are current as of the measurement date. For financial instruments that do not have readily determinable fair values using quoted market prices, the determination of fair value is based upon consideration of available information, including types of financial instruments, current financial information, restrictions on dispositions, fair values of underlying financial instruments and quotations for similar instruments.
	The valuation of financial instruments may include the use of valuation models and other techniques. Adjustments to valuations derived from valuation models may be made when, in management's judgment, features of the financial instrument such as its complexity, the market in which the financial instrument is traded and risk uncertainties about market conditions require that an adjustment be made to the value derived from the models. Adjustments from the price derived from a valuation model reflect management's judgment that other participants in the market for the financial instrument being measured at fair value would also consider in valuing that same financial instrument. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment.
	The availability of observable inputs can vary and is affected by a wide variety of factors, including, for example, the type of financial instrument and market conditions. As the observability of prices and inputs may change for a financial instrument from period to period, this condition may cause a transfer of an instrument among the fair value hierarchy levels. Transfers among the levels are recognized at the beginning of each period. The degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3.
	Jefferies Valuation Process for Financial Instruments
	The Jefferies Independent Price Verification ("IPV") Group, which is part of the Jefferies finance department, in partnership with Jefferies Risk Management, is responsible for establishing Jefferies valuation policies and procedures. The IPV Group and Risk Management, which are independent of business functions, play an important role and serve as a control function in determining that Jefferies financial instruments are appropriately valued and that fair value measurements are reliable. This is particularly important where prices or valuations that require inputs are less observable. In the event that observable inputs are not available, the control processes are designed to assure that the valuation approach utilized is appropriate and consistently applied and that the assumptions are reasonable. The IPV Group reports to the Jefferies Global Controller and is subject to the oversight of the IPV Committee, which includes senior members of Jefferies finance department and other personnel. Jefferies independent price verification policies and procedures are reviewed, at a minimum, annually and changes to the policies require the approval of the IPV Committee.
	Price Testing Process. Jefferies business units are responsible for determining the fair value of Jefferies financial instruments using approved valuation models and methodologies. In order to ensure that the business unit valuations represent a fair value exit price, the IPV Group tests and validates the fair value of the financial instruments inventory. In the testing process, the IPV Group obtains prices and valuation inputs from sources independent of Jefferies, consistently adheres to established procedures set forth in the valuation policies for sourcing prices and valuation inputs and utilizing valuation methodologies. Sources used to validate fair value prices and inputs include, but are not limited to, exchange data, recently executed transactions, pricing data obtained from third party vendors, pricing and valuation services, broker quotes and observed comparable transactions.
	To the extent discrepancies between the business unit valuations and the pricing or valuations resulting from the price testing process are identified, such discrepancies are investigated by the IPV Group and fair values are adjusted, as appropriate. The IPV Group maintains documentation of its testing, results, rationale and recommendations and prepares a monthly summary of its valuation results. This process also forms the basis for the classification of fair values within the fair value hierarchy (i.e., Level 1, Level 2 or Level 3). The IPV Group utilizes the additional expertise of Risk Management personnel in valuing more complex financial instruments and financial instruments with less or limited pricing observability. The results of the valuation testing are reported to the IPV Committee on a monthly basis, which discusses the results and is charged with the final conclusions as to the financial instrument fair values in the consolidated financial statements. This process specifically assists management in asserting as to the fair presentation of our financial condition and results of operations as included within our Quarterly Reports on Form 10-Q and Annual Report on Form 10-K. At each quarter end, the overall valuation results, as concluded upon by the IPV Committee, are presented to the Jefferies Audit Committee.
	Judgment exercised in determining Level 3 fair value measurements is supplemented by daily analysis of profit and loss performed by the Product Control functions. Gains and losses, which result from changes in fair value, are evaluated and corroborated daily based on an understanding of each of the trading desks' overall risk positions and developments in a particular market on the given day. Valuation techniques generally rely on recent transactions of suitably comparable financial instruments and use the observable inputs from those comparable transactions as a validation basis for Level 3 inputs. Level 3 fair value measurements are further validated through subsequent sales testing and market comparable sales, if such information is available. Level 3 fair value measurements require documentation of the valuation rationale applied, which is reviewed for consistency in application from period to period; and the documentation includes benchmarking the assumptions underlying the valuation rationale against relevant analytic data.
	Third Party Pricing Information. Pricing information obtained from external data providers (including independent pricing services and brokers) may incorporate a range of market quotes from dealers, recent market transactions and benchmarking model derived prices to quoted market prices and trade data for comparable securities. External pricing data is subject to evaluation for reasonableness by the IPV Group using a variety of means including comparisons of prices to those of similar product types, quality and maturities, consideration of the narrowness or wideness of the range of prices obtained, knowledge of recent market transactions and an assessment of the similarity in prices to comparable dealer offerings in a recent time period. Jefferies has a process whereby it challenges the appropriateness of pricing information obtained from external data providers (including independent pricing services and brokers) in order to validate the data for consistency with the definition of a fair value exit price. Jefferies process includes understanding and evaluating the external data providers' valuation methodologies. For corporate, U.S. government and agency, municipal debt securities, and loans, to the extent independent pricing services or broker quotes are utilized in our valuation process, the vendor service providers are collecting and aggregating observable market information as to recent trade activity and active bid-ask submissions. The composite pricing information received from the independent pricing service is not based on unobservable inputs or proprietary models. For mortgage- and other asset-backed securities and collateralized debt obligations, the independent pricing services use a matrix evaluation approach incorporating both observable yield curves and market yields on comparable securities as well as implied inputs from observed trades for comparable securities in order to determine prepayment speeds, cumulative default rates and loss severity. Further, Jefferies considers pricing data from multiple service providers as available as well as compares pricing data to prices observed for recent transactions, if any, in order to corroborate valuation inputs.
	Model Review Process. Where a pricing model is to be used to determine fair value, the pricing model is reviewed for theoretical soundness and appropriateness by Risk Management, independent from the trading desks, and then approved by Risk Management to be used in the valuation process. Review and approval of a model for use may include benchmarking the model against relevant third party valuations, testing sample trades in the model, backtesting the results of the model against actual trades and stress-testing the sensitivity of the pricing model using varying inputs and assumptions. In addition, recently executed comparable transactions and other observable market data are considered for purposes of validating assumptions underlying the model. Models are independently reviewed and validated by Risk Management annually or more frequently if market conditions or use of the valuation model changes.
	Receivables
	At March 31, 2015 and December 31, 2014, Receivables include receivables from brokers, dealers and clearing organizations of $2,222.3 million and $2,187.5 million, respectively, and receivables from customers of securities operations of $1,343.6 million and $1,250.5 million, respectively.
	Payables, expense accruals and other liabilities
	At March 31, 2015 and December 31, 2014, Payables, expense accruals and other liabilities include payables to brokers, dealers and clearing organizations of $2,663.0 million and $2,280.1 million, respectively, and payables to customers of securities operations of $4,757.5 million and $6,242.0 million, respectively.
	Accounting Developments
	Discontinued Operations. In January 2015, we adopted new Financial Accounting Standards Board ("FASB") guidance on the reporting of discontinued operations. The new guidance requires that disposal of a component of an entity or a group of components of an entity be reported as discontinued operations if the disposal represents a strategic shift that has (or will have) a major effect on an entity's operations and financial results, and would require expanded disclosures. The adoption of this guidance did not have an impact on our consolidated financial statements.
	Revenue Recognition. In May 2014, the FASB issued new guidance that defines how companies report revenues from contracts with customers, and also requires enhanced disclosures. The core principle of this new guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. This guidance will be effective for interim and annual periods beginning after December 15, 2016. In April 2015, the FASB announced a proposal to defer the effective date by one year, with early adoption on the original effective date permitted. We are currently evaluating the impact this new guidance will have on our consolidated financial statements to the extent applicable.
	Repurchase Agreements. In January 2015, we adopted the FASB's new guidance that changes the accounting for repurchase-to-maturity transactions and linked repurchase financings to secured borrowing accounting, which is consistent with the accounting for other repurchase agreements. This guidance did not significantly affect our consolidated results of operations, financial condition or cash flows. Effective for interim periods beginning after March 31, 2015, the guidance also requires new disclosures about transfers that are accounted for as sales in transactions that are economically similar to repurchase agreements and increased transparency about the types of collateral pledged in repurchase agreements and similar transactions accounted for as secured borrowings. We will provide the additional disclosures in our consolidated financial statements.
	Consolidation. In February 2015, the FASB issued new guidance that amends current consolidation guidance including changes to both the variable and voting interest models used to evaluate whether an entity should be consolidated. This guidance also eliminates the deferral of certain consolidation standards for entities considered to be investment companies. This guidance will be effective for annual and interim periods beginning after December 15, 2015, and early adoption is permitted. We are evaluating the impact this new guidance will have on our consolidated financial statements.
	Debt Issuance Costs. In April 2015, the FASB issued new guidance that requires debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability. This guidance will be effective for annual and interim periods beginning after December 15, 2015, and early adoption is permitted. The adoption of this guidance is not expected to have a significant impact on our consolidated statement of financial condition.

Fair_Value_Disclosures

Fair Value Disclosures	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Disclosures	Note 3. Fair Value Disclosures
	The following is a summary of our financial instruments, trading liabilities and investments in managed funds that are accounted for at fair value on a recurring basis by level within the fair value hierarchy at March 31, 2015 and December 31, 2014 (in thousands):
		31-Mar-15
									Counterparty
									and
									Cash
									Collateral
			Level 1 (1)		Level 2 (1)		Level 3		Netting (2)			Total
	Assets:
	Trading assets, at fair value:
	Corporate equity securities	$	3,052,340	$	209,338	$	18,210	$	–		$	3,279,888
	Corporate debt securities		–		3,399,249		30,735		–			3,429,984
	Collateralized debt obligations		–		153,900		90,897		–			244,797
	U.S. government and federal agency securities		3,783,645		106,427		–		–			3,890,072
	Municipal securities		–		772,940		–		–			772,940
	Sovereign obligations		1,522,227		1,057,623		333		–			2,580,183
	Residential mortgage-backed securities		–		2,824,500		79,953		–			2,904,453
	Commercial mortgage-backed securities		–		542,089		24,629		–			566,718
	Other asset-backed securities		–		138,391		7,146		–			145,537
	Loans and other receivables		–		1,349,201		111,410		–			1,460,611
	Derivatives		96,660		5,083,829		46,136		(4,729,533	)		497,092
	Investments at fair value		–		3		193,094		–			193,097
	Investment in FXCM		–		–		947,000		–			947,000
	Physical commodities		–		58,715		–		–			58,715
	Total trading assets	$	8,454,872	$	15,696,205	$	1,549,543	$	(4,729,533	)	$	20,971,087
	Available for sale securities:
	Corporate equity securities	$	73,993	$	–	$	–	$	–		$	73,993
	Corporate debt securities		–		29,528		–		–			29,528
	U.S. government securities		213,611		–		–		–			213,611
	Residential mortgage-backed securities		–		498,876		–		–			498,876
	Commercial mortgage-backed securities		–		27,914		–		–			27,914
	Other asset-backed securities		–		130,508		–		–			130,508
	Total available for sale securities	$	287,604	$	686,826	$	–	$	–		$	974,430
	Cash and cash equivalents	$	3,524,524	$	–	$	–	$	–		$	3,524,524
	Investments in managed funds	$	–	$	160,456	$	433,125	$	–		$	593,581
	Cash and securities segregated and on deposit for regulatory
	purposes or deposited with clearing and depository
	organizations (3)	$	3,186,319	$	–	$	–	$	–		$	3,186,319
	Securities received as collateral	$	4,821	$	–	$	–	$	–		$	4,821
	Liabilities:
	Trading liabilities:
	Corporate equity securities	$	2,031,013	$	60,034	$	38	$	–		$	2,091,085
	Corporate debt securities		–		1,766,453		–		–			1,766,453
	U.S. government and federal agency securities		1,366,689		99,422		–		–			1,466,111
	Sovereign obligations		707,844		659,846		–		–			1,367,690
	Residential mortgage-backed securities		–		11,925		–		–			11,925
	Loans		–		910,569		9,327		–			919,896
	Derivatives		71,707		5,011,935		49,450		(4,810,751	)		322,341
	Total trading liabilities	$	4,177,253	$	8,520,184	$	58,815	$	(4,810,751	)	$	7,945,501
	Other secured financings	$	–	$	–	$	65,602	$	–		$	65,602
	Obligation to return securities received as collateral	$	4,821	$	–	$	–	$	–		$	4,821
		31-Dec-14
									Counterparty
									and
									Cash
									Collateral
			Level 1 (1)		Level 2 (1)		Level 3		Netting (2)			Total
	Assets:
	Trading assets, at fair value:
	Corporate equity securities	$	3,130,892	$	226,441	$	20,964	$	–		$	3,378,297
	Corporate debt securities		–		3,342,276		55,918		–			3,398,194
	Collateralized debt obligations		–		306,218		91,498		–			397,716
	U.S. government and federal agency securities		2,694,268		81,273		–		–			2,775,541
	Municipal securities		–		590,849		–		–			590,849
Sovereign obligations		1,968,747		790,764		–		–			2,759,511
Residential mortgage-backed securities		–		2,879,954		82,557		–			2,962,511
Commercial mortgage-backed securities		–		966,651		26,655		–			993,306
Other asset-backed securities		–		137,387		2,294		–			139,681
Loans and other receivables		–		1,458,760		97,258		–			1,556,018
Derivatives		65,145		5,046,278		54,190		(4,759,345	)		406,268
Investments at fair value		–		73,152		119,212		–			192,364
Physical commodities		–		62,234		–		–			62,234
Total trading assets	$	7,859,052	$	15,962,237	$	550,546	$	(4,759,345	)	$	19,612,490
Available for sale securities:
Corporate equity securities	$	89,353	$	–	$	–	$	–		$	89,353
Corporate debt securities		–		30,403		–		–			30,403
U.S. government securities		593,773		–		–		–			593,773
Residential mortgage-backed securities		–		606,683		–		–			606,683
Commercial mortgage-backed securities		–		43,401		–		–			43,401
Other asset-backed securities		–		245,156		–		–			245,156
Total available for sale securities	$	683,126	$	925,643	$	–	$	–		$	1,608,769
Cash and cash equivalents	$	4,276,775	$	–	$	–	$	–		$	4,276,775
Investments in managed funds	$	–	$	226,488	$	54,982	$	–		$	281,470
Cash and securities segregated and on deposit for regulatory
purposes or deposited with clearing and depository
organizations (3)	$	3,444,674	$	–	$	–	$	–		$	3,444,674
Securities received as collateral	$	5,418	$	–	$	–	$	–		$	5,418
Liabilities:
Trading liabilities:
Corporate equity securities	$	1,934,469	$	74,681	$	38	$	–		$	2,009,188
Corporate debt securities		–		1,611,994		223		–			1,612,217
Collateralized debt obligations		–		4,557		–		–			4,557
U.S. government and federal agency securities		2,253,055		–		–		–			2,253,055
Sovereign obligations		1,217,075		574,010		–		–			1,791,085
Loans		–		856,525		14,450		–			870,975
Derivatives		52,778		5,117,803		49,552		(4,856,618	)		363,515
Total trading liabilities	$	5,457,377	$	8,239,570	$	64,263	$	(4,856,618	)	$	8,904,592
Other secured financings	$	–	$	–	$	30,825	$	–		$	30,825
Obligation to return securities received as collateral	$	5,418	$	–	$	–	$	–		$	5,418
(1) There were no transfers between Level 1 and Level 2 during the three months ended March 31, 2015. During the year ended December 31, 2014, equity options presented within Trading assets and Trading liabilities of $6.1 million and $6.6 million, respectively, were transferred from Level 1 to Level 2 as adjustments were incorporated into the valuation approach for such contracts to estimate the point within the bid-ask range that meets the best estimate of fair value.
(2) Represents counterparty and cash collateral netting across the levels of the fair value hierarchy for positions with the same counterparty.
(3) Securities comprise U.S. government securities segregated for regulatory purposes with a fair value of $434.8 million and $453.7 million at March 31, 2015 and December 31, 2014, respectively, and Commodities Futures Trading Commission ("CFTC") approved money market funds with a fair value of $810.0 million and $545.0 million at March 31, 2015 and December 31, 2014, respectively.
The following is a description of the valuation basis, including valuation techniques and inputs, used in measuring our financial assets and liabilities that are accounted for at fair value on a recurring basis:
Corporate Equity Securities
Exchange Traded Equity Securities: Exchange traded equity securities are measured based on quoted closing exchange prices, which are generally obtained from external pricing services, and are categorized within Level 1 of the fair value hierarchy, otherwise they are categorized within Level 2 or Level 3 of the fair value hierarchy.
Non-exchange Traded Equity Securities: Non-exchange traded equity securities are measured primarily using broker quotations, pricing data from external pricing services and prices observed for recently executed market transactions and are categorized within Level 2 of the fair value hierarchy. Where such information is not available, non-exchange traded equity securities are categorized within Level 3 of the fair value hierarchy and measured using valuation techniques involving quoted prices of or market data for comparable companies, similar company ratios and multiples (e.g., price/EBITDA, price/book value), discounted cash flow analyses and transaction prices observed for subsequent financing or capital issuance by the company. When using pricing data of comparable companies, judgment must be applied to adjust the pricing data to account for differences between the measured security and the comparable security (e.g., issuer market capitalization, yield, dividend rate, geographical concentration).
Equity Warrants: Non-exchange traded equity warrants are generally categorized within Level 3 of the fair value hierarchy and are measured using the Black-Scholes model with key inputs impacting the valuation including the underlying security price, implied volatility, dividend yield, interest rate curve, strike price and maturity date.
Corporate Debt Securities
Corporate Bonds: Corporate bonds are measured primarily using pricing data from external pricing services and broker quotations, where available, prices observed for recently executed market transactions of comparable size, and bond spreads or credit default swap spreads of the issuer adjusted for basis differences between the swap curve and the bond curve. Corporate bonds measured using these valuation methods are categorized within Level 2 of the fair value hierarchy. If broker quotes, pricing data or spread data is not available, alternative valuation techniques are used including cash flow models incorporating interest rate curves, single name or index credit default swap curves for comparable issuers and recovery rate assumptions. Corporate bonds measured using alternative valuation techniques are categorized within Level 3 of the fair value hierarchy and comprise a limited portion of our corporate bonds.
High Yield Corporate and Convertible Bonds: A significant portion of our high yield corporate and convertible bonds are categorized within Level 2 of the fair value hierarchy and are measured primarily using broker quotations and pricing data from external pricing services, where available, and prices observed for recently executed market transactions of comparable size. Where pricing data is less observable, valuations are categorized within Level 3 and are based on pending transactions involving the issuer or comparable issuers, prices implied from an issuer's subsequent financings or recapitalizations, models incorporating financial ratios and projected cash flows of the issuer and market prices for comparable issuers.
Collateralized Debt Obligations
Collateralized debt obligations are measured based on prices observed for recently executed market transactions of the same or similar security or based on valuations received from third party brokers or data providers and are categorized within Level 2 or Level 3 of the fair value hierarchy depending on the observability and significance of the pricing inputs. Valuation that is based on recently executed market transitions of similar securities incorporates additional review and analysis of pricing inputs and comparability criteria including but not limited to collateral type, tranche type, rating, origination year, prepayment rates, default rates, and severities.
U.S. Treasury Securities: U.S. Treasury securities are measured based on quoted market prices and categorized within Level 1 of the fair value hierarchy.
U.S. Agency Issued Debt Securities: Callable and non-callable U.S. agency issued debt securities are measured primarily based on quoted market prices obtained from external pricing services. Non-callable U.S. agency securities are generally categorized within Level 1 and callable U.S. agency securities are categorized within Level 2 of the fair value hierarchy.
Municipal Securities
Municipal securities are measured based on quoted prices obtained from external pricing services and are generally categorized within Level 2 of the fair value hierarchy.
Sovereign Obligations
Foreign sovereign government obligations are measured based on quoted market prices obtained from external pricing services, where available, or recently executed independent transactions of comparable size. To the extent external price quotations are not available or recent transactions have not been observed, valuation techniques incorporating interest rate yield curves and country spreads for bonds of similar issuers, seniority and maturity are used to determine fair value of sovereign bonds or obligations. Foreign sovereign government obligations are classified in Level 1, Level 2 or Level 3 of the fair value hierarchy, primarily based on the country of issuance.
Residential Mortgage-Backed Securities
Agency Residential Mortgage-Backed Securities: Agency residential mortgage-backed securities include mortgage pass- through securities (fixed and adjustable rate), collateralized mortgage obligations and interest-only and principal-only securities and are generally measured using market price quotations from external pricing services and categorized within Level 2 of the fair value hierarchy.
Agency Residential Interest-Only and Inverse Interest-Only Securities ("Agency Inverse IOs"): The fair value of Agency Inverse IOs is estimated using expected future cash flow techniques that incorporate prepayment models and other prepayment assumptions to amortize the underlying mortgage loan collateral. We use prices observed for recently executed transactions to develop market-clearing spread and yield curve assumptions. Valuation inputs with regard to the underlying collateral incorporate weighted average coupon, loan-to-value, credit scores, geographic location, maximum and average loan size, originator, servicer, and weighted average loan age. Agency Inverse IOs are categorized within Level 2 or Level 3 of the fair value hierarchy. We also use vendor data in developing our assumptions, as appropriate.
Non-Agency Residential Mortgage-Backed Securities: Fair values are determined primarily using discounted cash flow methodologies and securities are categorized within Level 2 or Level 3 of the fair value hierarchy based on the observability and significance of the pricing inputs used. Performance attributes of the underlying mortgage loans are evaluated to estimate pricing inputs, such as prepayment rates, default rates and the severity of credit losses. Attributes of the underlying mortgage loans that affect the pricing inputs include, but are not limited to, weighted average coupon; average and maximum loan size; loan-to-value; credit scores; documentation type; geographic location; weighted average loan age; originator; servicer; historical prepayment, default and loss severity experience of the mortgage loan pool; and delinquency rate. Yield curves used in the discounted cash flow models are based on observed market prices for comparable securities and published interest rate data to estimate market yields.
Commercial Mortgage-Backed Securities
Agency Commercial Mortgage-Backed Securities: Government National Mortgage Association ("GNMA") project loans are measured based on inputs corroborated from and benchmarked to observed prices of recent securitization transactions of similar securities with adjustments incorporating an evaluation for various factors, including prepayment speeds, default rates, and cash flow structures as well as the likelihood of pricing levels in the current market environment.
Federal National Mortgage Association ("FNMA") Delegated Underwriting and Servicing ("DUS") mortgage-backed securities are generally measured by using prices observed for recently executed market transactions to estimate market- clearing spread levels for purposes of estimating fair value. GNMA project loan bonds and FNMA DUS mortgage- backed securities are categorized within Level 2 of the fair value hierarchy.
Non-Agency Commercial Mortgage-Backed Securities: Non-agency commercial mortgage-backed securities are measured using pricing data obtained from external pricing services and prices observed for recently executed market transactions and are categorized within Level 2 and Level 3 of the fair value hierarchy.
Other Asset-Backed Securities
Other asset-backed securities include, but are not limited to, securities backed by auto loans, credit card receivables and student loans and are categorized within Level 2 and Level 3 of the fair value hierarchy. Valuations are determined using pricing data obtained from external pricing services and prices observed for recently executed market transactions.
Loans and Other Receivables
Corporate Loans: Corporate loans categorized within Level 2 of the fair value hierarchy are measured based on market price quotations where market price quotations from external pricing services are supported by market transaction data.
Corporate loans categorized within Level 3 of the fair value hierarchy are measured based on market price quotations that are considered to be less transparent, market prices for debt securities of the same creditor, and estimates of future cash flow incorporating assumptions regarding creditor default and recovery rates and consideration of the issuer's capital structure.
Participation Certificates in Agency Residential Loans: Valuations of participation certificates in agency residential loans are based on observed market prices of recently executed purchases and sales of similar loans. The loan participationcertificates are categorized within Level 2 of the fair value hierarchy given the observability and volume of recently executed transactions and availability of data provider pricing.
Project Loans and Participation Certificates in GNMA Project and Construction Loans: Valuations of participation certificates in GNMA project and construction loans are based on inputs corroborated from and benchmarked to observed prices of recent securitizations of assets with similar underlying loan collateral to derive an implied spread. Securitization prices are adjusted to estimate the fair value of the loans incorporating an evaluation for various factors, including prepayment speeds, default rates, and cash flow structures as well as the likelihood of pricing levels in the current market environment. The measurements are categorized within Level 2 of the fair value hierarchy given the observability and volume of recently executed transactions.
Consumer Loans and Funding Facilities: Consumer and small business whole loans and related funding facilities are valued based on observed market transactions incorporating additional valuation inputs including, but not limited to, delinquency and default rates, prepayment rates, borrower characteristics, loan risk grades and loan age. These assets are categorized within Level 2 or Level 3 of the fair value hierarchy.
Escrow and Trade Claim Receivables: Escrow and trade claim receivables are categorized within Level 3 of the fair value hierarchy where fair value is estimated based on reference to market prices and implied yields of debt securities of the same or similar issuers. Escrow and trade claim receivables are categorized within Level 2 of the fair value hierarchy where fair value is based on recent trade activity in the same security.
Derivatives
Listed Derivative Contracts: Listed derivative contracts that are actively traded are measured based on quoted exchange prices, which are generally obtained from external pricing services, and are categorized within Level 1 of the fair value hierarchy. Listed derivatives for which there is limited trading activity are measured based on incorporating the closing auction price of the underlying equity security, use similar valuation approaches as those applied to over-the-counter derivative contracts and are categorized within Level 2 of the fair value hierarchy.
OTC Derivative Contracts: Over-the-counter ("OTC") derivative contracts are generally valued using models, whose inputs reflect assumptions that we believe market participants would use in valuing the derivative in a current period transaction. Inputs to valuation models are appropriately calibrated to market data. For many OTC derivative contracts, the valuation models do not involve material subjectivity as the methodologies do not entail significant judgment and the inputs to valuation models do not involve a high degree of subjectivity as the valuation model inputs are readily observable or can be derived from actively quoted markets. OTC derivative contracts are primarily categorized within Level 2 of the fair value hierarchy given the observability and significance of the inputs to the valuation models. Where significant inputs to the valuation are unobservable, derivative instruments are categorized within Level 3 of the fair value hierarchy.
OTC options include OTC equity, foreign exchange and commodity options measured using various valuation models, such as the Black-Scholes, with key inputs impacting the valuation including the underlying security, foreign exchange spot rate or commodity price, implied volatility, dividend yield, interest rate curve, strike price and maturity date. Discounted cash flow models are utilized to measure certain OTC derivative contracts including the valuations of our interest rate swaps, which incorporate observable inputs related to interest rate curves, valuations of our foreign exchange forwards and swaps, which incorporate observable inputs related to foreign currency spot rates and forward curves and valuations of our commodity swaps and forwards, which incorporate observable inputs related to commodity spot prices and forward curves. Credit default swaps include both index and single-name credit default swaps. External prices are available as inputs in measuring index credit default swaps and single-name credit default swaps. For commodity and equity total return swaps, market prices are observable for the underlying asset and used as the basis for measuring the fair value of the derivative contracts. Total return swaps executed on other underlyings are measured based on valuations received from external pricing services.
Investment in FXCM
In January 2015, we entered into a credit agreement with FXCM Inc., and provided FXCM a $300 million two-year senior secured term loan with rights to a variable proportion of certain distributions in connection with an FXCM sale of assets or certain other events, and to require a sale of FXCM beginning in January 2018. FXCM is an online provider of foreign exchange trading and related services. The loan has an initial interest rate of 10% per annum, increasing by 1.5% per annum each quarter, not to exceed 20.5% per annum. The variable proportion of distributions is as follows: 100% until amounts due under the loan are repaid; 50% of the next $350 million; then 90% of an amount equal to two times the balance outstanding on the term loan as of April 16, 2015 (not to be less than $500 million or more than $680 million); and 60% of all amounts thereafter. During the first quarter of 2015, we received $18.6 million of principal and interest payments from FXCM, and $287.6 million remained outstanding under the credit agreement as of March 31, 2015. As of May 7, 2015, we have received an additional $69.3 million, and $228.4 million remained outstanding under the credit agreement.
FXCM is considered a variable interest entity and our term loan with rights is a variable interest. We have determined that we are not the primary beneficiary of FXCM because we do not have the power to direct the activities that most significantly impact FXCM's performance. Therefore, we are not consolidating FXCM.
We view the FXCM loan and associated rights as one integrated transaction; since the rights, as derivatives, are accounted for at fair value, we have elected the fair value option for the loan. The total amount of our investment in FXCM is reported within Trading assets, at fair value in our Consolidated Statements of Financial Condition, and unrealized and realized changes in value, including the component related to interest income on the loan, are included within Principal transactions in the Consolidated Statements of Operations. During the first quarter of 2015, we recorded in Principal transactions an aggregate $686.6 million of unrealized and realized gains and interest income relating to our investment in FXCM. Our maximum exposure to loss as a result of our involvement with FXCM is limited to the carrying value of our investment ($947.0 million at March 31, 2015).
We engaged an independent valuation firm to assist management in estimating the fair value of our loan and rights in FXCM. Our estimate of fair value was determined using valuation models with inputs including management's assumptions concerning the amount and timing of expected cash flows; the loan's implied credit rating and effective yield; implied total equity value, based primarily on the publicly traded FXCM stock price; volatility; risk-free rate; and term. Because of these inputs and the degree of judgment involved, we have categorized our investment in FXCM in Level 3. The valuation is most significantly impacted by the inputs and assumptions related to the publicly traded stock price and volatility. A $0.30 change in the price of FXCM's shares alone (representing about 14% of the price at March 31, 2015), would result in a change of about $51 million in this valuation, assuming no change in any other factors we considered. Likewise, a 10% change in the assumed volatility would result in a change of about $29 million in this valuation, assuming no other change in any other factors. As we adjust to fair value each quarter, we anticipate volatility in the FXCM valuation, which could materially impact our results in a given period.
Physical Commodities
Physical commodities include base and precious metals and are measured using observable inputs including spot prices and published indices. Physical commodities are categorized within Level 2 of the fair value hierarchy. To facilitate the trading in precious metals we undertake leasing of such precious metals. The fees earned or paid for such leases are recorded as revenues in the Consolidated Statements of Operations.
Investments at Fair Value and Investments in Managed Funds
Investments at fair value and Investments in managed funds include investments in hedge funds, fund of funds, private equity funds, convertible bond funds and other funds, which are measured at fair value based on the net asset value of the funds provided by the fund managers and are categorized within Level 2 or Level 3 of the fair value hierarchy. Investments at fair value also include direct equity investments in private companies, which are measured at fair value using valuation techniques involving quoted prices of or market data for comparable companies, similar company ratios and multiples (e.g., price/EBITDA, price/book value), discounted cash flow analyses and transaction prices observed for subsequent financing or capital issuance by the company. Direct equity investments in private companies are categorized within Level 2 or Level 3 of the fair value hierarchy. Additionally, investments at fair value include investments in insurance contracts relating to our defined benefit plan in Germany. Fair value for the insurance contracts is determined using a third party and is categorized within Level 3 of the fair value hierarchy. The following tables present information about our investments in entities that have the characteristics of an investment company (in thousands).
					Redemption
				Unfunded	Frequency
		Fair Value (1)		Commitments	(if currently eligible)
31-Mar-15
Equity Long/Short Hedge Funds (2)	$	480,302	$	–	-2
High Yield Hedge Funds (3)		196		–	–
Fund of Funds (4)		340		94	–
Equity Funds (5)		40,403		25,670	–
Convertible Bond Funds (6)		3,470		–	At Will
Multi-strategy Fund (7)		108,150		–	–
Total (8)	$	632,861	$	25,764
31-Dec-14
Equity Long/Short Hedge Funds (2)	$	146,134	$	–	Monthly/Quarterly
High Yield Hedge Funds (3)		204		–	–
Fund of Funds (4)		323		94	–
Equity Funds (5)		65,216		26,023	–
Convertible Bond Funds (6)		3,355		–	At Will
Multi-strategy Fund (7)		105,954		–	–
Total (8)	$	321,186	$	26,117
(1) Where fair value is calculated based on net asset value, fair value has been derived from each of the funds' capital statements.
(2) This category includes investments in hedge funds that invest, long and short, in equity securities in domestic and international markets in both the public and private sectors. At March 31, 2015, investments with a fair value of $78.0 million and at December 31, 2014 substantially all of the investments in this category are redeemable with 30 to 90 days prior written notice, and includes an investment in a private asset management fund managed by us with a fair value of $48.8 million and $117.2 million at March 31, 2015 and December 31, 2014, respectively. At March 31, 2015, this category also includes investments in two Folger Hill feeder funds that invest solely in a Folger Hill master fund that makes long/short equity investments, with broad industry and geographic diversification. Investment in these funds is subject to a lock-up until August 15, 2019, subject to certain release events and other withdrawal rights. Following this date, investments can be redeemed as of any calendar quarter-end with no less than 45 calendar days' notice, subject to certain limitations. At March 31, 2015, our investments in these two funds had an aggregate fair value of $402.3 million.
(3) Includes investments in funds that invest in domestic and international public high yield debt, private high yield investments, senior bank loans, public leveraged equities, distressed debt, and private equity investments. There are no redemption provisions. The underlying assets of the funds are being liquidated and we are unable to estimate when the underlying assets will be fully liquidated.
(4) Includes investments in fund of funds that invest in various private equity funds. At March 31, 2015 and December 31, 2014, approximately 96% and 95%, respectively, of the fair value of investments in this category is managed by us and has no redemption provisions, instead distributions are received through the liquidation of the underlying assets of the fund of funds, which are estimated to be liquidated in approximately two years. For the remaining investments, we have requested redemption; however, we are unable to estimate when these funds will be received.
(5) At March 31, 2015 and December 31, 2014, investments representing approximately 99% and 99%, respectively, of the fair value of investments in this category include investments in equity funds that invest in the equity of various U.S. and foreign private companies in the energy, technology, internet service and telecommunication service industries. These investments cannot be redeemed; instead distributions are received through the liquidation of the underlying assets of the funds which are expected to liquidate in one to eight years. The remaining investments are in liquidation and we are unable to estimate when the underlying assets will be fully liquidated.
(6) Investment in the Jefferies Umbrella Fund, an open-ended investment company managed by us that invests primarily in convertible bonds. The investment is redeemable with five days prior written notice.
(7) Investment in private asset management fund managed by us that employs a variety of investment strategies and can invest in U.S. and non-U.S. equity and equity related securities, futures, exchange traded funds, fixed income securities, preferred securities, options, forward contracts and swaps. Withdrawals from the fund prior to the first year anniversary of the investment are subject to a 5% withdrawal fee and withdrawals during any calendar quarter are limited to 25% of the fund's net asset value. Both of these restrictions can be waived by us, in our sole discretion.
(8) Investments at fair value in the Consolidated Statements of Financial Condition at March 31, 2015 and December 31, 2014, include $153.8 million and $152.6 million, respectively, of direct investments which do not have the characteristics of investment companies and therefore not included within this table.
Other Secured Financings
Other secured financings that are accounted for at fair value include notes issued by consolidated VIEs, which are classified as Level 2 or Level 3 within the fair value hierarchy. Fair value is based on recent transaction prices for similar assets. In addition, at March 31, 2015 and December 31, 2014, Other secured financings includes $5.6 million and $7.8 million, respectively, related to transfers of loans accounted for as secured financings rather than as sales and classified as Level 3 within the fair value hierarchy.
Pricing Information
Our trading assets and trading liabilities are measured using different valuation bases as follows:
	31-Mar-15				31-Dec-14
	Trading Assets		Trading Liabilities		Trading Assets		Trading Liabilities
Exchange closing prices	14	%	25	%	16	%	20	%
Recently observed transaction prices	4	%	3	%	4	%	2	%
External pricing services	66	%	64	%	67	%	69	%
Broker quotes	4	%	4	%	4	%	3	%
Valuation techniques	12	%	4	%	9	%	6	%
	100	%	100	%	100	%	100	%
The following is a summary of changes in fair value of our financial assets and liabilities that have been categorized within Level 3 of the fair value hierarchy for the three months ended March 31, 2015 (in thousands):
Three Months Ended March 31, 2015
																								Changes in
																								unrealized
																								gains (losses)
																								relating to
					Total gains																			instruments
		Balance,			(losses)														Net transfers			Balance,		still held at
		December 31,			(realized and														into (out of)			March 31,		March 31,
		2014			unrealized) (1)			Purchases			Sales			Settlements			Issuances		Level 3			2015		2015 (1)
Assets:
Trading assets:
Corporate equity securities	$	20,964		$	63		$	–		$	(168	)	$	–		$	–	$	(2,649	)	$	18,210	$	243
Corporate debt securities		55,918			(1,930	)		469			(533	)		–			–		(23,189	)		30,735		(1,577	)
Collateralized debt obligations		91,498			(16,022	)		–			(13,519	)		(1,296	)		–		30,236			90,897		(15,886	)
Sovereign obligations		–			13			–			(1	)		–			–		321			333		12
Residential mortgage-backed
securities		82,557			(2,863	)		2,100			(1,375	)		(23	)		–		(443	)		79,953		783
Commercial mortgage-backed
securities		26,655			(531	)		–			(382	)		(6,864	)		–		5,751			24,629		(1,369	)
Other asset-backed securities		2,294			(167	)		26			(1	)		–			–		4,994			7,146		(167	)
Loans and other receivables		97,258			(5,033	)		40,019			(16,122	)		(15,448	)		–		10,736			111,410		(3,262	)
Investments at fair value		119,212			609			5,010			(594	)		(277	)		–		69,134			193,094		614
Investment in FXCM		–			686,627			279,000			–			(18,627	)		–		–			947,000		686,627
Investments in managed funds		54,982			(22,211	)		400,354			–			–			–		–			433,125		(22,210	)
Liabilities:
Trading liabilities:
Corporate equity securities	$	38		$	–		$	–		$	–		$	–		$	–	$	–		$	38	$	–
Corporate debt securities		223			(115	)		(6,683	)		6,698			–			–		(123	)		–		–
Net derivatives (2)		(4,638	)		6,938			–			–			(58	)		1,072		–			3,314		(8,771	)
Loans		14,450			(39	)		(2,877	)		825			–			–		(3,032	)		9,327		39
Other secured financings		30,825			–			–			–			(2,218	)		36,995		–			65,602		–
(1) Realized and unrealized gains (losses) are reported in Principal transactions in the Consolidated Statements of Operations, except for realized and unrealized gains (losses) on Investments in managed funds, which are included in Other revenues in the Consolidated Statements of Operations.
(2) Net derivatives represent Trading assets - Derivatives and Trading liabilities - Derivatives.
Analysis of Level 3 Assets and Liabilities for the three months ended March 31, 2015
During the three months ended March 31, 2015, transfers of assets of $205.2 million from Level 2 to Level 3 of the fair value hierarchy are attributed to:
Non-agency residential mortgage-backed securities of $35.3 million, commercial mortgage-backed securities of $10.3 million and other asset-backed securities of $5.0 million for which no recent trade activity was observed for purposes of determining observable inputs;
Loans and other receivables of $16.4 million due to a lower number of contributors comprising vendor quotes to support classification within Level 2;
Collateralized debt obligations of $64.5 million which have little to no transparency related to trade activity;
Corporate debt securities of $2.4 million, corporate equity securities of $1.7 million and investments at fair value of $69.2 million due to a lack of observable market transactions.
During the three months ended March 31, 2015, transfers of assets of $110.3 million from Level 3 to Level 2 are attributed to:
Non-agency residential mortgage-backed securities of $35.7 million and commercial mortgage-backed securities of $4.5 million for which market trades were observed in the period for either identical or similar securities;
Collateralized debt obligations of $34.3 million and loans and other receivables of $5.7 million due to a greater number of contributors for certain vendor quotes supporting classification into Level 2;
Corporate debt securities of $25.6 million and corporate equity securities of $4.4 million due to an increase in observable market transactions.
During the three months ended March 31, 2015, there were transfers of loan liabilities of $3.0 million from Level 3 to Level 2 due to an increase in observable inputs in the valuation.
Net gains on Level 3 assets were $638.6 million and net losses on Level 3 liabilities were $6.9 million for three months ended March 31, 2015. Net gains on Level 3 assets were primarily due to increased valuations of our investment in FXCM and certain investments at fair value partially offset by decreased valuations of certain investments in managed funds, collateralized debt obligations, loans and other receivables, residential and commercial mortgage-backed securities and corporate debt securities. Net losses on Level 3 liabilities were primarily due to increased valuations of certain derivatives.
The following is a summary of changes in fair value of our financial assets and liabilities that have been categorized within Level 3 of the fair value hierarchy for the three months ended March 31, 2014 (in thousands):
																						Changes in
																						unrealized
																						gains (losses)
																						relating to
				Total gains																		instruments
		Balance,		(losses)													Net transfers			Balance,		still held at
		December 31,		(realized and													into (out of)			March 31,		March 31,
		2013		unrealized) (1)			Purchases			Sales			Settlements		Issuances		Level 3			2014		2014 (1)
Assets:
Trading assets:
Corporate equity securities	$	9,884	$	(1,393	)	$	134		$	–		$	–	$	–	$	3,716		$	12,341	$	(1,319	)
Corporate debt securities		25,666		(2,014	)		4,136			(624	)		–		–		2,151			29,315		193
Collateralized debt obligations		37,216		10,184			76,511			(78,081	)		(144	)	–		20,342			66,028		5,662
Residential mortgage-backed															–
securities		105,492		(1,626	)		9,637			(13,703	)		(1,755	)	–		18,947			116,992		(2,097	)
Commercial mortgage-backed
securities		17,568		(3,032	)		8,933			(14,645	)		(50	)	–		8,712			17,486		(958	)
Other asset-backed securities		12,611		72			2,250			(2,048	)		(83	)	–		(10,427	)		2,375		7
Loans and other receivables		145,890		(3,902	)		36,213			(49,475	)		(935	)	–		1,041			128,832		(3,807	)
Investments at fair value		101,242		24,889			22,500			(9,012	)		–		–		(776	)		138,843		24,889
Investments in managed funds		57,285		(2,859	)		5,102			–			–		–		–			59,528		(2,859	)
Liabilities:
Trading liabilities:
Corporate equity securities	$	38	$	8		$	–		$	411		$	–	$	–	$	558		$	1,015	$	(8	)
Net derivatives (2)		6,905		1,267			(1,327	)		2,169			197		–		(3,438	)		5,773		(1,267	)
Loans		22,462		(153	)		(18,913	)		4,887			–		–		1,977			10,260		(153	)
Other secured financings		8,711		–			–			–			–		21,683		–			30,394		–
(1) Realized and unrealized gains (losses) are reported in Principal transactions in the Consolidated Statements of Operations, except for realized and unrealized gains (losses) on Investments in managed funds, which are included in Other revenues in the Consolidated Statements of Operations.
(2) Net derivatives represent Trading assets - Derivatives and Trading liabilities - Derivatives.
Analysis of Level 3 Assets and Liabilities for the three months ended March 31, 2014
During the three months ended March 31, 2014, transfers of assets of $91.0 million from Level 2 to Level 3 of the fair value hierarchy are attributed to:
Non-agency residential mortgage-backed securities of $38.1 million, commercial mortgage-backed securities of $9.0 million and other asset-backed securities of $1.8 million for which no recent trade activity was observed for purposes of determining observable inputs;
Loans and other receivables of $8.9 million due to a lower number of contributors comprising vendor quotes to support classification within Level 2;
Corporate equity securities of $7.4 million and corporate debt securities of $2.3 million due to lack of observable market transactions;
Collateralized debt obligations of $23.5 million which have little to no transparency in trade activity.
During the three months ended March 31, 2014, transfers of assets of $47.3 million from Level 3 to Level 2 are attributed to:
Non-agency residential mortgage-backed securities of $19.1 million, commercial mortgage-backed securities of $0.2 million and other asset-backed securities of $12.2 million for which market trades were observed in the period for either identical or similar securities;
Collateralized debt obligations of $3.3 million, loans and other receivables of $7.9 million and investments at fair value of $0.8 million due to a greater number of contributors for certain vendor quotes supporting classification into Level 2;
Corporate equity securities of $3.6 million and corporate debt securities of $0.2 million due to an increase in observable market transactions.
During the three months ended March 31, 2014, there were transfers of loan liabilities of $2.9 million from Level 3 to Level 2 and transfers of $4.8 million from Level 2 to Level 3 due to an increase and decrease in observable inputs in the valuation, respectively. There were $3.4 million transfers of net derivative liabilities from Level 3 to Level 2 due to an increase in observable inputs used in the valuing of derivative contracts.
Net gains on Level 3 assets were $20.3 million and net losses on Level 3 liabilities were $1.1 million for the three months ended March 31, 2014. Net gains on Level 3 assets were primarily due to increased valuations of certain collateralized debt obligations and investments at fair value, partially offset by a decrease in valuation of certain corporate equity securities, corporate debt securities, residential and commercial mortgage-backed securities, loans and other receivables and investments in managed funds. Net losses on Level 3 liabilities were primarily due to increased valuations of certain derivative instruments, partially offset by decrease in valuation of certain loan positions.
Quantitative Information about Significant Unobservable Inputs used in Level 3 Fair Value Measurements
The tables below present information on the valuation techniques, significant unobservable inputs and their ranges for our financial assets and liabilities, subject to threshold levels related to the market value of the positions held, measured at fair value on a recurring basis with a significant Level 3 balance. The range of unobservable inputs could differ significantly across different firms given the range of products across different firms in the financial services sector. The inputs are not representative of the inputs that could have been used in the valuation of any one financial instrument; i.e., the input used for valuing one financial instrument within a particular class of financial instruments may not be appropriate for valuing other financial instruments within that given class. Additionally, the ranges of inputs presented below should not be construed to represent uncertainty regarding the fair values of our financial instruments; rather the ranges of inputs are reflective of the differences in the underlying characteristics of the financial instruments in each category.
For certain categories, we have provided a weighted average of the inputs allocated based on the fair values of the financial instruments comprising the category. We do not believe that the range or weighted average of the inputs is indicative of the reasonableness of uncertainty of our Level 3 fair values. The range and weighted average are driven by the individual financial instruments within each category and their relative distribution in the population. The disclosed inputs when compared with the inputs as disclosed in other quarters should not be expected to necessarily be indicative of changes in our estimates of unobservable inputs for a particular financial instrument as the population of financial instruments comprising the category will vary from period to period based on purchases and sales of financial instruments during the period as well as transfers into and out of Level 3 each period.
31-Mar-15
		Fair Value	Valuation	Significant			Weighted
Financial Instruments Owned		(in thousands)	Technique	Unobservable Input(s)	Input/Range		Average
Corporate equity securities	$	18,210
Non-exchange traded securities			Market approach	EBITDA (a) multiple	3.5to 8.6		4.4
			Scenario analysis	Estimated recovery percentage	78%		–
Corporate debt securities	$	24,795	Convertible bond model	Discount rate/yield	32%		–
Collateralized debt obligations	$	51,095	Discounted cash flows	Constant prepayment rate	0% to 20%		14	%
				Constant default rate	0% to 2%		2	%
				Loss severity	0% to 70%		42	%
				Yield	6% to 20%		13	%
Residential mortgage-backed securities	$	79,953	Discounted cash flows	Constant prepayment rate	2% to 50%		13	%
				Constant default rate	2% to 100%		21	%
				Loss severity	35% to 80%		52	%
				Yield	1% to 13%		6	%
Commercial mortgage-backed securities	$	24,629	Discounted cash flows	Yield	8% to 22%		14	%
				Cumulative loss rate	1.9% to 73%		16	%
			Scenario analysis	Estimated recovery percentage	81%		–
Other asset-backed securities	$	7,146	Discounted cash flows	Constant prepayment rate	4% to 6%		4	%
				Constant default rate	3% to 4%		4	%
				Loss severity	50% to 60%		52	%
				Yield	6% to 7%		6	%
Loans and other receivables	$	102,034	Comparable pricing	Comparable loan price	$100 to $101	$	100.5
			Market approach	Yield	3% to 9%		7	%
				EBITDA (a) multiple	8.2		–
			Scenario analysis	Estimated recovery percentage	10% to 81%		37	%
			Discounted cash flows	Constant prepayment rate	20%		–
				Constant default rate	2%		–
				Loss severity	25%		–
				Yield	11%		–
Derivatives	$	46,136
Foreign exchange options			Option model	Volatility	12% to 23%		15	%
Commodity forwards			Discounted cash flows	Discount rate	20%		–
Loan commitments			Comparable pricing	Comparable loan price	$71 to $100	$	99
				Yield	8%		–
Investments at fair value
Private equity securities	$	32,312	Market approach	Transaction Level	$57		–
			Market approach	Discount rate	15% to 30%		23	%
Investment in FXCM	$	310,000	Discounted cash flows	Term based on the pay off	6 months to 1.8 years		0.8	years
Term loan		637,000	Option pricing model	Volatility	65%		–
Unfunded commitments	$	947,000					–
		Fair Value	Valuation	Significant			Weighted
Trading Liabilities		(in thousands)	Technique	Unobservable Input(s)	Input/Range		Average
Derivatives	$	49,450
FX options			Option model	Volatility	12% to 23%		15	%
Unfunded commitments			Comparable pricing	Comparable loan price	$71 to $100	$	78.6
			Market approach	Yield	5% to 8%		8	%
			Discounted cash flows	Constant prepayment rate	20%		–
				Constant default rate	2%		–
				Loss severity	25%		–
				Yield	11%		–
Loans	$	9,327	Comparable pricing	Comparable loan price	$100		–
Other secured financings	$	65,602	Comparable pricing	Comparable loan price	$82 to $100	$	98.9
31-Dec-14
		Fair Value	Valuation	Significant				Weighted
Financial Instruments Owned		(in thousands)	Technique	Unobservable Input(s)		Input/Range		Average
Corporate equity securities	$	19,814
Non-exchange traded securities			Market approach	EBITDA (a) multiple		3.4to 4.7		3.6
			Scenario analysis	Estimated recovery percentage		24%		–
Corporate debt securities	$	22,766	Convertible bond model	Discount rate/yield		32%		–
Collateralized debt obligations	$	41,784	Discounted cash flows	Constant prepayment rate		0% to 20%		13	%
				Constant default rate		0% to 2%		2	%
				Loss severity		0% to 70%		39	%
				Yield		2% to 51%		16	%
Residential mortgage-backed securities	$	82,557	Discounted cash flows	Constant prepayment rate		1% to 50%		13	%
				Constant default rate		1% to 100%		14	%
				Loss severity		20% to 80%		50	%
				Yield		3% to 13%		7	%
Commercial mortgage-backed securities	$	26,655	Discounted cash flows	Yield		8% to 12%		11	%
				Cumulative loss rate		4% to 72%		15	%
			Scenario analysis	Estimated recovery percentage		90%		–
Other asset-backed securities	$	2,294	Discounted cash flows	Constant prepayment rate		8%		–
				Constant default rate		3%		–
				Loss severity		70%		–
				Yield		7%		–
Loans and other receivables	$	88,154	Comparable pricing	Comparable loan price		$100 to $101	$	100.3
			Market approach	Yield		3% to 5%		4	%
				EBITDA (a) multiple		3.4to 8.2		7.6
			Scenario analysis	Estimated recovery percentage		10% to 41%		36	%
Derivatives	$	54,190
Foreign exchange options			Option model	Volatility		13% to 23%		17	%
Commodity forwards			Discounted cash flows	Discount rate		17%		–
Loan commitments			Comparable pricing	Comparable loan price		$100		–
Investments at fair value
Private equity securities	$	32,323	Market approach	Transaction Level		$50		–
			Market approach	Discount rate		15% to 30%		23	%
		Fair Value	Valuation	Significant				Weighted
Trading Liabilities		(in thousands)	Technique	Unobservable Input(s)		Input/Range		Average
Derivatives	$	49,552
FX options			Option model	Volatility		13% to 23%		17	%
Unfunded commitments			Comparable pricing	Comparable loan price		$89 to $100	$	92
				Credit spread		45bps		–
			Market approach	Yield		5%		–
Loans	$	14,450	Comparable pricing	Comparable loan price		$100		–
Other secured financings	$	30,825	Comparable pricing	Comparable loan price		$81 to $100	$	98.7
(a) Earnings before interest, taxes, depreciation and amortization ("EBITDA").
The fair values of certain Level 3 assets and liabilities that were determined based on third-party pricing information, unadjusted past transaction prices, reported net asset value or a percentage of the reported enterprise fair value are excluded from the above table. At March 31, 2015 and December 31, 2014, asset exclusions consisted of $618.5 million and $180.0 million, respectively, primarily comprised of investments in non-exchange traded securities, private equity securities, investments in reinsurance contracts, certain corporate loans and at March 31, 2015, investments in managed funds. At March 31, 2015 and December 31, 2014, liability exclusions consisted of $0 million and $0.3 million, respectively, of corporate loan commitments.
Sensitivity of Fair Values to Changes in Significant Unobservable Inputs
For recurring fair value measurements categorized within Level 3 of the fair value hierarchy, the sensitivity of the fair value measurement to changes in significant unobservable inputs and interrelationships between those unobservable inputs (if any) are described below:
Private equity securities, corporate debt securities, loans and other receivables and loan commitments using comparable pricing valuation techniques. A significant increase (decrease) in the comparable share, bond or loan price in isolation would result in a significant higher (lower) fair value measurement.
Non-exchange traded securities, corporate debt securities, and loans and other receivables using a market approach valuation technique. A significant increase (decrease) in the EBITDA or other multiples in isolation would result in a significantly higher (lower) fair value measurement. A significant increase (decrease) in the yield of a corporate debt security, loan and other receivable would result in a significantly lower (higher) fair value measurement. A significant increase (decrease) in the discount rate of a private equity security would result in a significantly lower (higher) fair value measurement.
Corporate debt securities, and loans and other receivables using scenario analysis. A significant increase (decrease) in the possible recovery rates of the cash flow outcomes underlying the investment would result in a significantly higher (lower) fair value measurement for the financial instrument.
Collateralized debt obligations, residential and commercial mortgage-backed securities and other asset-backed securities using a discounted cash flow valuation technique. A significant increase (decrease) in isolation in the constant default rate, loss severities or cumulative loss rate and discount rate would result in a significantly lower (higher) fair value measurement. The impact of changes in the constant prepayment rate would have differing impacts depending on the capital structure of the security. A significant increase (decrease) in the loan or bond yield would result in a significant lower (higher) fair value measurement.
Derivative equity options and equity warrants using an option model. A significant increase (decrease) in volatility would result in a significant higher (lower) fair value measurement.
Private equity securities using a net asset value technique. A significant increase (decrease) in the discount applied to net asset value would result in a significant (lower) higher fair value measurement.
Investment in FXCM using a discounted cash flow valuation technique and an option pricing model. A significant increase in term based on the time to pay off the loan would result in a significant higher fair value measurement. A significant increase (decrease) in volatility or time to liquidity event would result in a significant lower (higher) fair value measurement.
Fair Value Option Election
We have elected the fair value option for all loans and loan commitments made by Jefferies capital markets businesses. These loans and loan commitments include loans entered into by Jefferies investment banking division in connection with client bridge financing and loan syndications, loans purchased by Jefferies leveraged credit trading desk as part of its bank loan trading activities and mortgage loan commitments and fundings in connection with mortgage-backed securitization activities. Loans and loan commitments originated or purchased by Jefferies leveraged credit and mortgage-backed businesses are managed on a fair value basis. Loans are included in Trading assets and loan commitments are included in Trading assets and Trading liabilities. The fair value option election is not applied to loans made to affiliate entities as such loans are entered into as part of ongoing, strategic business ventures. Loans to affiliate entities are included within Loans to and investments in associated companies and are accounted for on an amortized cost basis. We have also elected the fair value option for certain financial instruments held by Jefferies subsidiaries as the investments are risk managed on a fair value basis. The fair value option has also been elected for certain secured financings that arise in connection with Jefferies securitization activities and other structured financings. Other secured financings, receivables from brokers, dealers and clearing organizations, receivables from customers of securities operations, payables to brokers, dealers and clearing organizations and payables to customers of securities operations, are accounted for at cost plus accrued interest rather than at fair value; however, the recorded amounts approximate fair value due to their liquid or short-term nature.
The following is a summary of gains (losses) due to changes in instrument specific credit risk on loans and other receivables and loan commitments measured at fair value under the fair value option for the three months ended March 31, 2015 and 2014 (in thousands):
		2015			2014
Financial Instruments Owned:
Loans and other receivables	$	5,389		$	4,467
Financial Instruments Sold:
Loans	$	(1,022	)	$	(462	)
Loan commitments	$	(7,166	)	$	(2,357	)
The following is a summary of the amount by which contractual principal exceeds fair value for loans and other receivables measured at fair value under the fair value option (in thousands):
		March 31,			December 31,
		2015			2014
Loans and other receivables (1)	$	426,425		$	403,119
Loans and other receivables greater than 90 days past due (1)	$	28,829		$	5,594
Loans and other receivables on nonaccrual status (1) (2)	$	(36,471	)	$	(22,360	)
(1) Interest income is recognized separately from other changes in fair value and is included within Interest income in the Consolidated Statements of Operations.
(2) Amounts include all loans and other receivables greater than 90 days past due.
The aggregate fair value of loans and other receivables that were greater than 90 days past due was $14.1 million and $0 million at March 31, 2015 and December 31, 2014, respectively.
The aggregate fair value of loans and other receivables on nonaccrual status, which includes all loans and other receivables greater than 90 days past due, was $285.7 million and $274.6 million at March 31, 2015 and December 31, 2014, respectively.
We have elected the fair value option for Jefferies investment in KCG Holdings, Inc. The change in the fair value of this investment was $34.6 million and $(1.0) million for three months ended March 31, 2015 and 2014, respectively.
At March 31, 2015 and December 31, 2014, we owned approximately 46.6 million common shares of HRG, representing approximately 23% of HRG's outstanding common shares, which are accounted for under the fair value option. The shares are included in our Consolidated Statements of Financial Condition at fair value of $581.6 million and $659.9 million at March 31, 2015 and December 31, 2014, respectively. The shares were acquired at an aggregate cost of $475.6 million. The change in the fair value of our investment in HRG aggregated $(78.3) million during the three month period ended March 31, 2015 which is included in other merchant banking businesses and $32.6 million during the three months ended March 31, 2014, of which $12.7 million is included in other merchant banking businesses and $19.9 million is included in Jefferies results of operations for the period it owned certain of these shares. We currently have two directors on HRG's board. We have agreed not to increase our interest in HRG above 27.5% through March 17, 2016. The shares have the benefit of a registration rights agreement, and may be otherwise sold consistent with the securities laws; however, we have agreed not to sell the shares to a party if after such sale the party would own in excess of 4.9% of HRG common stock.
We believe accounting for these investments at fair value better reflected the economics of these investments, and quoted market prices for these investments provides an objectively determined fair value at each balance sheet date. Our investment in HomeFed is the only investment accounted for under the equity method of accounting that is also a publicly traded company for which we did not elect the fair value option. HomeFed's common stock is not listed on any stock exchange, and price information for the common stock is not regularly quoted on any automated quotation system. It is traded in the over-the-counter market with high and low bid prices published by the National Association of Securities Dealers OTC Bulletin Board Service; however, trading volume is minimal. For these reasons we did not elect the fair value option for HomeFed.

Derivative_Financial_Instrumen

Derivative Financial Instruments	3 Months Ended
	Mar. 31, 2015
Derivative Financial Instruments [Abstract]
Derivative Financial Instruments	Note 4. Derivative Financial Instruments
	Off-Balance Sheet Risk
	Jefferies has contractual commitments arising in the ordinary course of business for securities loaned or purchased under agreements to resell, repurchase agreements, future purchases and sales of foreign currencies, securities transactions on a when-issued basis and underwriting. Each of these financial instruments and activities contains varying degrees of off-balance sheet risk whereby the fair values of the securities underlying the financial instruments may be in excess of, or less than, the contract amount. The settlement of these transactions is not expected to have a significant effect upon our consolidated financial statements.
	Derivative Financial Instruments
	Derivative activities are recorded at fair value in the Consolidated Statements of Financial Condition in Trading assets and Trading liabilities, net of cash paid or received under credit support agreements and on a net counterparty basis when a legal right to offset exists under a master netting agreement. Net realized and unrealized gains and losses are recognized in Principal transactions in the Consolidated Statements of Operations on a trade date basis and as a component of cash flows from operating activities in the Consolidated Statements of Cash Flows. Acting in a trading capacity, Jefferies may enter into derivative transactions to satisfy the needs of its clients and to manage its own exposure to market and credit risks resulting from trading activities. See Notes 3 and 21 for additional disclosures about derivative financial instruments.
	Derivatives are subject to various risks similar to other financial instruments, including market, credit and operational risk. The risks of derivatives should not be viewed in isolation, but rather should be considered on an aggregate basis along with our other trading-related activities. Jefferies manages the risks associated with derivatives on an aggregate basis along with the risks associated with proprietary trading as part of its firm wide risk management policies. In connection with Jefferies derivative activities, Jefferies may enter into International Swaps and Derivative Association, Inc. ("ISDA") master netting agreements and similar agreements with counterparties. These agreements provide Jefferies with the ability to offset a counterparty's rights and obligations, request additional collateral when necessary or liquidate the collateral in the event of counterparty default. See Note 10 for additional information with respect to financial statement offsetting.
	The following tables present the fair value and related number of derivative contracts categorized by type of derivative contract as reflected in the Consolidated Statements of Financial Condition at March 31, 2015 and December 31, 2014. The fair value of assets/liabilities related to derivative contracts represents our receivable/payable for derivative financial instruments, gross of counterparty netting and cash collateral received and pledged (in thousands, except contract amounts):
		Assets					Liabilities
					Number of				Number of
			Fair Value		Contracts		Fair Value		Contracts
	31-Mar-15
	Interest rate contracts	$	2,688,316		78,835	$	2,633,960		124,133
	Foreign exchange contracts		1,366,539		14,138		1,327,400		12,867
	Equity contracts		836,053		1,909,862		838,598		1,889,424
	Commodity contracts		245,818		941,231		215,191		948,122
	Credit contracts: centrally cleared swaps		79,540		102		84,075		88
	Credit contracts: other credit derivatives		10,359		38		33,868		42
	Total		5,226,625				5,133,092
	Counterparty/cash-collateral netting		(4,729,533	)			(4,810,751	)
	Total per Consolidated Statement of Financial Condition	$	497,092			$	322,341
	31-Dec-14
	Interest rate contracts	$	2,299,807		71,505	$	2,292,691		89,861
	Foreign exchange contracts		1,514,881		12,861		1,519,349		12,752
	Equity contracts		1,050,990		2,271,507		1,058,015		2,051,469
	Commodity contracts		276,726		1,031,568		303,206		1,020,418
	Credit contracts: centrally cleared swaps		17,831		27		23,264		22
	Credit contracts: other credit derivatives		5,378		18		23,608		27
	Total		5,165,613				5,220,133
	Counterparty/cash-collateral netting		(4,759,345	)			(4,856,618	)
	Total per Consolidated Statement of Financial Condition	$	406,268			$	363,515
	The following table presents unrealized and realized gains (losses) on derivative contracts for the three months ended March 31, 2015 and 2014 (in thousands):
			2015			2014
	Interest rate contracts	$	(42,793	)	$	(5,118	)
	Foreign exchange contracts		15,172			6,067
	Equity contracts		71,041			(96,236	)
	Commodity contracts		14,491			16,186
	Credit contracts		(6,042	)		(3,878	)
	Total	$	51,869		$	(82,979	)
	OTC Derivatives. The following tables set forth by remaining contract maturity the fair value of OTC derivative assets and liabilities as reflected in the Consolidated Statement of Financial Condition at March 31, 2015 (in thousands):
		OTC Derivative Assets (1) (2) (3)
									Cross-
							Greater Than		Maturity
			0-12 Months		1-5 Years		5 Years		Netting (4)			Total
	Commodity swaps, options and forwards	$	57,079	$	2,674	$	23,599	$	(2,915	)	$	80,437
	Equity swaps and options		8,894		31,585		5,657		–			46,136
	Credit default swaps		–		–		7,442		(254	)		7,188
	Total return swaps		10,135		377		–		(299	)		10,213
	Foreign currency forwards, swaps and options		376,842		48,591		90		(23,179	)		402,344
	Interest rate swaps, options and forwards		45,809		178,897		125,598		(68,866	)		281,438
	Total	$	498,759	$	262,124	$	162,386	$	(95,513	)		827,756
	Cross product counterparty netting											(21,605	)
	Total OTC derivative assets included in
	Trading assets										$	806,151
	(1) At March 31, 2015, we held exchange traded derivative assets and other credit agreements with a fair value of $67.9 million, which are not included in this table.
	(2) OTC derivative assets in the table above are gross of collateral received. OTC derivative assets are recorded net of collateral received in the Consolidated Statements of Financial Condition. At March 31, 2015 cash collateral received was $377.0 million.
	(3) Derivative fair values include counterparty netting within product category.
	(4) Amounts represent the netting of receivable balances with payable balances for the same counterparty within product category across maturity categories.
		OTC Derivative Liabilities (1) (2) (3)
									Cross-
							Greater Than		Maturity
			0-12 Months		1-5 Years		5 Years		Netting (4)			Total
	Commodity swaps, options and forwards	$	68,406	$	254	$	5,377	$	(2,915	)	$	71,122
	Equity swaps and options		4,670		59,118		19,452		–			83,240
	Credit default swaps		254		6,242		2,103		(254	)		8,345
Total return swaps		15,733		1,412		–		(299	)		16,846
Foreign currency forwards, swaps and options		326,435		60,213		–		(23,179	)		363,469
Fixed income forwards		431		–		–		–			431
Interest rate swaps, options and forwards		50,381		106,084		143,283		(68,866	)		230,882
Total	$	466,310	$	233,323	$	170,215	$	(95,513	)		774,335
Cross product counterparty netting											(21,605	)
Total OTC derivative liabilities included in
Trading liabilities										$	752,730
(1) At March 31, 2015, we held exchange traded derivative liabilities and other credit agreements with a fair value of $28.0 million, which are not included in this table.
(2) OTC derivative liabilities in the table above are gross of collateral pledged. OTC derivative liabilities are recorded net of collateral pledged in the Consolidated Statements of Financial Condition. At March 31, 2015, cash collateral pledged was $458.4 million.
(3) Derivative fair values include counterparty netting within product category.
(4) Amounts represent the netting of receivable balances with payable balances for the same counterparty within product category across maturity categories.
At March 31, 2015, the counterparty credit quality with respect to the fair value of our OTC derivative assets was as follows (in thousands):
Counterparty credit quality (1):
A- or higher	$	508,060
BBB- to BBB+		107,645
BB+ or lower		94,772
Unrated		95,674
Total	$	806,151
(1) We utilize internal credit ratings determined by Jefferies Risk Management. Credit ratings determined by Risk Management use methodologies that produce ratings generally consistent with those produced by external rating agencies.
Contingent Features
Certain of Jefferies derivative instruments contain provisions that require their debt to maintain an investment grade credit rating from each of the major credit rating agencies. If Jefferies debt were to fall below investment grade, it would be in violation of these provisions and the counterparties to the derivative instruments could request immediate payment or demand immediate and ongoing full overnight collateralization on Jefferies derivative instruments in liability positions. The aggregate fair value of all derivative instruments with such credit-risk-related contingent features that are in a liability position at March 31, 2015 and December 31, 2014 is $298.6 million and $269.0 million, respectively, for which Jefferies has posted collateral of $279.0 million and $234.6 million, respectively, in the normal course of business. If the credit-risk-related contingent features underlying these agreements were triggered on March 31, 2015 and December 31, 2014, Jefferies would have been required to post an additional $36.5 million and $55.1 million, respectively, of collateral to its counterparties.

Collateralized_Transactions

Collateralized Transactions	3 Months Ended
	Mar. 31, 2015
Collateralized Transactions [Abstract]
Collateralized Transactions	Note 5. Collateralized Transactions
	Jefferies enters into secured borrowing and lending arrangements to obtain collateral necessary to effect settlement, finance trading asset inventory positions, meet customer needs or re-lend as part of dealer operations. Jefferies monitors the fair value of the securities loaned and borrowed on a daily basis as compared with the related payable or receivable, and requests additional collateral or returns excess collateral, as appropriate. Jefferies pledges financial instruments as collateral under repurchase agreements, securities lending agreements and other secured arrangements, including clearing arrangements. Jefferies agreements with counterparties generally contain contractual provisions allowing the counterparty the right to sell or repledge the collateral. Pledged securities owned that can be sold or repledged by the counterparty are included within Financial instruments owned and noted parenthetically as Securities pledged on our Consolidated Statements of Financial Condition.
	Jefferies receives securities as collateral under resale agreements, securities borrowing transactions and customer margin loans. Jefferies also receives securities as collateral in connection with securities-for-securities transactions in which it is the lender of securities. In many instances, Jefferies is permitted by contract or custom to rehypothecate the securities received as collateral. These securities may be used to secure repurchase agreements, enter into securities lending transactions, satisfy margin requirements on derivative transactions or cover short positions. At March 31, 2015 and December 31, 2014, the approximate fair value of securities received as collateral by Jefferies that may be sold or repledged was $23.1 billion and $25.8 billion, respectively. A substantial portion of these securities have been sold or repledged.
	In instances where Jefferies receives securities as collateral in connection with securities-for-securities transactions in which Jefferies is the lender of securities and is permitted to sell or repledge the securities received as collateral, it reports the fair value of the collateral received and the related obligation to return the collateral in the Consolidated Statements of Financial Condition. At March 31, 2015 and December 31, 2014, $4.8 million and $5.4 million, respectively, were reported as Securities received as collateral and as Obligation to return securities received as collateral.

Securitization_Activities

Securitization Activities	3 Months Ended
	Mar. 31, 2015
Securitization Activities [Abstract]
Securitization Activities	Note 6. Securitization Activities
	Jefferies engages in securitization activities related to corporate loans, commercial mortgage loans and mortgage-backed and other asset-backed securities. In securitization transactions, Jefferies transfers assets to special purpose entities ("SPEs") and acts as the placement or structuring agent for the beneficial interests sold to investors by the SPE. A significant portion of the securitization transactions are securitization of assets issued or guaranteed by U.S. government agencies. These SPEs generally meet the criteria of variable interest entities; however, the SPEs are generally not consolidated as Jefferies is not considered the primary beneficiary for these SPEs. Beginning in the third quarter of 2014, another of our subsidiaries utilized an SPE to securitize automobile loans receivable. This SPE is a variable interest entity and our subsidiary is the primary beneficiary; the related assets and the secured borrowings are recognized in the Consolidated Statement of Financial Condition. These secured borrowings do not have recourse to our subsidiary's general credit. See Note 8 for further information on variable interest entities.
	Jefferies accounts for securitization transactions as sales provided it has relinquished control over the transferred assets. Transferred assets are carried at fair value with unrealized gains and losses reflected in the Consolidated Statements of Operations prior to the identification and isolation for securitization. Subsequently, revenues recognized upon securitization are reflected as net underwriting revenues. Jefferies generally receives cash proceeds in connection with the transfer of assets to an SPE. Jefferies may, however, have continuing involvement with the transferred assets, which is limited to retaining one or more tranches of the securitization (primarily senior and subordinated debt securities in the form of mortgage- and other asset-backed securities or collateralized loan obligations), which are included within Trading assets and are generally initially categorized as Level 2 within the fair value hierarchy. We apply fair value accounting to the securities. If Jefferies has not relinquished control over the transferred assets, the assets continue to be recognized in Trading assets and a corresponding liability is recognized in Other secured financings. The related liabilities do not have recourse to Jefferies general credit.
	The following table presents activity related to our securitizations that were accounted for as sales in which we had continuing involvement during the three months ended March 31, 2015 and 2014 (in millions):
			2015		2014
	Transferred assets	$	1,562.90	$	1,626.90
	Proceeds on new securitizations		1,564.50		1,628.10
	Cash flows received on retained interests		2.4		8.5
	Jefferies has no explicit or implicit arrangements to provide additional financial support to these SPEs, has no liabilities related to these SPEs and has no outstanding derivative contracts executed in connection with these securitizations at March 31, 2015 and December 31, 2014.
	The following table summarizes our retained interests in SPEs where Jefferies transferred assets and has continuing involvement and received sale accounting treatment (in millions):
			31-Mar-15				31-Dec-14
			Total		Retained		Total		Retained
	Securitization Type		Assets		Interests		Assets		Interests
	U.S. government agency residential mortgage-backed securities	$	11,742.90	$	403.7	$	19,196.90	$	226.9
	U.S. government agency commercial mortgage-backed securities		3,519.50		97.9		5,848.50		204.7
	Collateralized loan obligations		4,169.90		53.3		4,511.80		108.4
	Total assets represent the unpaid principal amount of assets in the SPEs in which Jefferies has continuing involvement and are presented solely to provide information regarding the size of the transaction and the size of the underlying assets supporting its retained interests, and are not considered representative of the risk of potential loss. Assets retained in connection with a securitization transaction represent the fair value of the securities of one or more tranches issued by an SPE, including senior and subordinated tranches. Jefferies risk of loss is limited to this fair value amount which is included within total Trading assets in our Consolidated Statements of Financial Condition.
	Although not obligated, in connection with secondary market-making activities Jefferies may make a market in the securities issued by these SPEs. In these market-making transactions, Jefferies buys these securities from and sells these securities to investors. Securities purchased through these market-making activities are not considered to be continuing involvement in these SPEs, although the securities are included in Trading assets. To the extent Jefferies purchased securities through these market-making activities and Jefferies is not deemed to be the primary beneficiary of the variable interest entity, these securities are included in agency and non-agency mortgage- and asset-backed securitizations in the nonconsolidated variable interest entities section presented in Note 8.

Available_For_Sale_Securities

Available For Sale Securities	3 Months Ended
	Mar. 31, 2015
Available For Sale Securities [Abstract]
Available For Sale Securities	Note 7. Available for Sale Securities
	The amortized cost, gross unrealized gains and losses and estimated fair value of investments classified as available for sale at March 31, 2015 and December 31, 2014 are as follows (in thousands):
					Gross		Gross		Estimated
			Amortized		Unrealized		Unrealized		Fair
			Cost		Gains		Losses		Value
	31-Mar-15
	Bonds and notes:
	U.S. government securities	$	213,621	$	3	$	13	$	213,611
	Residential mortgage-backed securities		490,171		9,156		451		498,876
	Commercial mortgage-backed securities		27,534		400		20		27,914
	Other asset-backed securities		130,584		286		362		130,508
	All other corporates		29,410		139		21		29,528
	Total fixed maturities		891,320		9,984		867		900,437
	Equity securities:
	Common stocks:
	Banks, trusts and insurance companies		24,687		14,696		–		39,383
	Industrial, miscellaneous and all other		19,092		15,518		–		34,610
	Total equity securities		43,779		30,214		–		73,993
		$	935,099	$	40,198	$	867	$	974,430
	31-Dec-14
	Bonds and notes:
	U.S. government securities	$	593,803	$	33	$	63	$	593,773
	Residential mortgage-backed securities		597,402		10,959		1,678		606,683
	Commercial mortgage-backed securities		42,991		484		74		43,401
	Other asset-backed securities		245,533		619		996		245,156
	All other corporates		30,519		60		176		30,403
	Total fixed maturities		1,510,248		12,155		2,987		1,519,416
	Equity securities:
	Common stocks:
	Banks, trusts and insurance companies		31,853		18,740		–		50,593
	Industrial, miscellaneous and all other		20,355		18,405		–		38,760
	Total equity securities		52,208		37,145		–		89,353
		$	1,562,456	$	49,300	$	2,987	$	1,608,769
	The amortized cost and estimated fair value of investments classified as available for sale at March 31, 2015, by contractual maturity, are shown below. Expected maturities are likely to differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.
			Amortized		Estimated
			Cost		Fair Value
		(In thousands)
	Due within one year	$	228,255	$	228,292
	Due after one year through five years		14,776		14,847
	Due after five years through ten years		–		–
	Due after ten years		–		–
			243,031		243,139
	Mortgage-backed and asset-backed securities		648,289		657,298
		$	891,320	$	900,437
	At March 31, 2015, the unrealized losses on investments which have been in a continuous unrealized loss position for less than 12 months and 12 months or longer were not significant.

Variable_Interest_Entities

Variable Interest Entities	3 Months Ended
	Mar. 31, 2015
Variable Interest Entities [Abstract]
Variable Interest Entities	Note 8. Variable Interest Entities
	Variable interest entities ("VIEs") are entities in which equity investors lack the characteristics of a controlling financial interest. VIEs are consolidated by the primary beneficiary. The primary beneficiary is the party who has both the power to direct the activities of a variable interest entity that most significantly impact the entity's economic performance and an obligation to absorb losses of the entity or a right to receive benefits from the entity that could potentially be significant to the entity.
	Our variable interests in VIEs include debt and equity interests, an equity interest in an associated company, commitments, guarantees and certain fees. Our involvement with VIEs arises primarily from the following activities of Jefferies, but also includes other activities discussed below:
	Purchases of securities in connection with our trading and secondary market making activities,
	Retained interests held as a result of securitization activities, including the resecuritization of mortgage- and other asset-backed securities and the securitization of commercial mortgage and corporate loans,
	Acting as placement agent and/or underwriter in connection with client-sponsored securitizations,
	Financing of agency and non-agency mortgage- and other asset-backed securities,
	Warehousing funding arrangements for client-sponsored consumer loan vehicles and collateralized loan obligations ("CLOs") through participation certificates and revolving loan commitments, and
	Loans to, investments in and fees from various investment fund vehicles.
	We determine whether we are the primary beneficiary of a VIE upon our initial involvement with the VIE and we reassess whether we are the primary beneficiary of a VIE on an ongoing basis. Our determination of whether we are the primary beneficiary of a VIE is based upon the facts and circumstances for each VIE and requires significant judgment. Our considerations in determining the VIE's most significant activities and whether we have power to direct those activities include, but are not limited to, the VIE's purpose and design and the risks passed through to investors, the voting interests of the VIE, management, service and/or other agreements of the VIE, involvement in the VIE's initial design and the existence of explicit or implicit financial guarantees. In situations where we have determined that the power over the VIE's most significant activities is shared, we assess whether we are the party with the power over the majority of the significant activities. If we are the party with the power over the majority of the significant activities, we meet the "power" criteria of the primary beneficiary. If we do not have the power over a majority of the significant activities or we determine that decisions require consent of each sharing party, we do not meet the "power" criteria of the primary beneficiary.
	We assess our variable interests in a VIE both individually and in aggregate to determine whether we have an obligation to absorb losses of or a right to receive benefits from the VIE that could potentially be significant to the VIE. The determination of whether our variable interest is significant to the VIE requires significant judgment. In determining the significance of our variable interest, we consider the terms, characteristics and size of the variable interests, the design and characteristics of the VIE, our involvement in the VIE and our market-making activities related to the variable interests.
	Consolidated VIEs
	The following tables present information about the assets and liabilities of our consolidated VIEs, which are presented within our Consolidated Statements of Financial Condition in the respective asset and liability categories, as of March 31, 2015 and December 31, 2014.
		Securitization Vehicles
			March 31,		December 31,
			2015		2014
			(In millions)
	Cash	$	0.4	$	0.5
	Financial instruments owned		65.6		62.7
	Securities purchased under agreement to resell (1)		795.4		575.2
	Other		97.2		107.1
	Total assets	$	958.6	$	745.5
	Other secured financings (2)	$	950.4	$	737
	Other		8.2		8.5
	Total liabilities	$	958.6	$	745.5
	(1) Securities purchased under agreement to resell represent an amount due under a collateralized transaction on a related consolidated entity, which is eliminated in consolidation.
	(2) Approximately $5.6 million and $39.7 million of the secured financing represents an amount held by Jefferies in inventory and eliminated in consolidation at March 31, 2015 and December 31, 2014, respectively.
	Securitization vehicles. Jefferies is the primary beneficiary of a securitization vehicle to which it transferred term loans backed by consumer installment receivables and retained a portion of the securities issued by the securitization vehicle. In the creation of the securitization vehicle, Jefferies was involved in the decisions made during the establishment and design of the entity and holds variable interests consisting of the securities retained that could potentially be significant. The assets of the VIE consist of the term loans backed by consumer installment receivables, which are available for the benefit of the vehicle's beneficial interest holders. The creditors of the VIE do not have recourse to Jefferies general credit and the assets of the VIE are not available to satisfy any other debt.
	Jefferies is the primary beneficiary of mortgage-backed financing vehicles to which Jefferies sells agency and non-agency residential and commercial mortgage-backed securities pursuant to the terms of a master repurchase agreement. Jefferies manages the assets within these vehicles. Jefferies variable interests in these vehicles consist of its collateral margin maintenance obligations under the master repurchase agreement. The assets of these VIEs consist of reverse repurchase agreements, which are available for the benefit of the vehicle's debt holders. The creditors of these VIEs do not have recourse to Jefferies general credit and each such VIE's assets are not available to satisfy any other debt.
	At March 31, 2015 and December 31, 2014, another of our subsidiaries is the primary beneficiary of an SPE it utilized to securitize automobile loans receivable. Our subsidiary acts as the servicer for which it receives a fee, and owns the equity interest in this SPE. The notes issued by the SPE are secured solely by the assets of the SPE and do not have recourse to our subsidiary's general credit and the assets of the VIE are not available to satisfy any other debt.
	Nonconsolidated VIEs
	The following tables present information about Jefferies variable interests in nonconsolidated VIEs.
		Variable Interests
			Financial Statement		Maximum
			Carrying Amount (3)		Exposure to Loss		VIE Assets
			Assets
		(In millions)
	31-Mar-15
	Collateralized loan obligations	$	75.4	$	817.9	$	8,125.20
	Consumer loan financing vehicles		175.3		758.8		411.6
	Asset management vehicles (1)		6		6		199.6
	Private equity vehicles (2)		23.7		48.3		70.8
	Total	$	280.4	$	1,631.00	$	8,807.20
	31-Dec-14
	Collateralized loan obligations	$	134	$	926.9	$	7,737.10
	Consumer loan financing vehicles		170.6		797.8		485.2
	Asset management vehicles (1)		11.3		11.3		432.3
	Private equity vehicles (2)		44.3		59.2		92.8
	Total	$	360.2	$	1,795.20	$	8,747.40
	(1) Assets consist of equity interests, which are included within Investments in managed funds, and accrued management and performance fees, which are included in Receivables.
	(2) Assets consist of equity interests, which are included in Investment in managed funds.
	(3) There were no significant liabilities at March 31, 2015 and December 31, 2014.
	Jefferies maximum exposure to loss often differs from the carrying value of the variable interests. The maximum exposure to loss is dependent on the nature of the variable interests in the VIEs and is limited to the notional amounts of certain loan commitments and guarantees. Jefferies maximum exposure to loss does not include the offsetting benefit of any financial instruments that may be utilized to hedge the risks associated with its variable interests and is not reduced by the amount of collateral held as part of a transaction with a VIE.
	Collateralized Loan Obligations. Assets collateralizing the CLOs include bank loans, participation interests and sub-investment grade and senior secured U.S. loans. Jefferies underwrites securities issued in CLO transactions on behalf of unaffiliated sponsors and provides advisory services to the unaffiliated sponsors. Jefferies may also sell corporate loans to the CLOs. Jefferies variable interests in connection with collateralized loan obligations where it has been involved in providing underwriting and/or advisory services consist of the following:
	Forward sale agreements whereby we commit to sell, at a fixed price, corporate loans and ownership interests in an entity holding such corporate loans to CLOs
	Warehouse funding arrangements in the form of participation interests in corporate loans held by CLOs and commitments to fund such participation interests
	Trading positions in securities issued in a CLO transaction
	Investments in variable funding notes issued by CLOs
	A guarantee to a CLO managed by Jefferies Finance, whereby we guarantee certain of the obligations of Jefferies Finance to the CLO
	In addition, Jefferies owns variable interests in CLOs previously managed by Jefferies. These variable interests consist of debt securities and a right to a portion of the CLOs' management and incentive fees. Jefferies exposure to loss from these CLOs is limited to its investments in the debt securities held. Management and incentives fees are accrued as the amounts become realizable. These CLOs represent interests in assets consisting primarily of senior secured loans, unsecured loans and high yield bonds.
	Consumer Loan Financing Vehicles. Jefferies provides financing and lending related services to certain client-sponsored VIEs in the form of revolving funding note agreements, revolving credit facilities and forward purchase agreements. The underlying assets, which are collateralizing the vehicles, are primarily comprised of unsecured consumer installment loans. In addition, Jefferies may provide structuring and advisory services and act as an underwriter or placement agent for securities issued by the vehicles. Jefferies does not control the activities of these entities.
	Asset Management Vehicles. Jefferies manages the Jefferies Umbrella Fund, an "umbrella structure" company that invests primarily in convertible bonds and enables investors to choose between one or more investment objectives by investing in one
	or more sub-funds within the same structure. Accounting changes to consolidation standards under GAAP have been deferred for entities that are considered to be investment companies; accordingly, consolidation continues to be determined under a risk and reward model. The Jefferies Umbrella Fund is subject to the deferral guidance and Jefferies is not the primary beneficiary under the risk and reward model. Jefferies variable interests in the Jefferies Umbrella Fund consist of equity interests, management fees and performance fees. See Note 2 for a discussion of new FASB guidance which will eliminate the deferral guidance upon adoption.
	Private Equity Vehicles. On July 26, 2010, Jefferies committed to invest equity of up to $75.0 million in Jefferies SBI USA Fund L.P. (the "SBI USA Fund L.P."). As of March 31, 2015 and December 31, 2014, Jefferies funded approximately $60.4 million and $60.1 million, respectively, of its commitment. The carrying amount of Jefferies equity investment was $22.7 million and $43.1 million at March 31, 2015 and December 31, 2014, respectively. Jefferies exposure to loss is limited to its equity commitment. The SBI USA Fund L.P. has assets consisting primarily of private equity and equity related investments.
Jefferies has a variable interest in Jefferies Employees Partners IV, LLC ("JEP IV") consisting of an equity investment. The carrying amount of Jefferies equity investment was $1.0 million and $1.2 million at March 31, 2015 and December 31, 2014, respectively. Jefferies exposure to loss is limited to its equity investment. JEP IV has assets consisting primarily of private equity and equity related investments.
Jefferies has provided a guarantee of a portion of Energy Partners I, LP's obligations under a credit agreement. Energy Partners I, LP, is a private equity fund owned and managed by certain of our employees. At March 31, 2015, the carrying value and maximum exposure to loss of the guarantee were $0 and $10.0 million, respectively. Energy Partners I, LP, has assets consisting primarily of debt and equity investments.
Mortgage- and Asset-Backed Vehicles. In connection with Jefferies secondary trading and market-making activities, Jefferies buys and sells agency and nonagency mortgage- and asset-backed securities, which are issued by third party securitization SPEs and are generally considered variable interests in VIEs. Securities issued by securitization SPEs are backed by residential mortgage loans, U.S. agency collateralized mortgage obligations, commercial mortgage loans, collateralized debt obligations and CLOs and other consumer loans, such as installment receivables, auto loans and student loans. These securities are accounted for at fair value and included in Trading assets in our Consolidated Statements of Financial Condition. Jefferies has no other involvement with the related SPEs and therefore does not consolidate these entities.
Jefferies also engages in underwriting, placement and structuring activities for third-party-sponsored securitization trusts generally through agency (Fannie Mae, Freddie Mac and Ginnie Mae) or nonagency sponsored SPEs and may purchase loans or mortgage-backed securities from third parties that are subsequently transferred into the securitization trusts. The securitizations are backed by residential and commercial mortgage, home equity and auto loans. Jefferies does not consolidate agency sponsored securitizations as it does not have the power to direct the activities of the SPEs that most significantly impact their economic performance. Further, Jefferies is not the servicer of nonagency-sponsored securitizations and therefore does not have power to direct the most significant activities of the SPEs and accordingly, does not consolidate these entities. Jefferies may retain unsold senior and/or subordinated interests at the time of securitization in the form of securities issued by the SPEs.
Jefferies transfers existing securities, typically mortgage-backed securities, into resecuritization vehicles. These transactions in which debt securities are transferred to a VIE in exchange for new beneficial interests occur in connection with both agency and nonagency sponsored VIEs. The consolidation analysis is largely dependent on Jefferies role and interest in the resecuritization trusts. Most resecuritizations in which Jefferies is involved are in connection with investors seeking securities with specific risk and return characteristics. As such, we have concluded that the decision-making power is shared between Jefferies and the investor(s), considering the joint efforts involved in structuring the trust and selecting the underlying assets as well as the level of security interests the investor(s) hold in the SPE; therefore, Jefferies does not consolidate the resecuritization VIEs.
At March 31, 2015 and December 31, 2014, Jefferies held $2,729.5 million and $3,186.9 million of agency mortgage-backed securities, respectively, and $930.1 million and $1,120.0 million of nonagency mortgage- and other asset-backed securities, respectively, as a result of its secondary trading and market-making activities, underwriting, placement and structuring activities and resecuritization activities. Jefferies maximum exposure to loss on these securities is limited to the carrying value of its investments in these securities. Mortgage- and other asset-backed securitization vehicles discussed within this section are not included in the above table containing information about Jefferies variable interests in nonconsolidated VIEs.
We also have a variable interest in a nonconsolidated VIE consisting of our equity interest in an associated company, Golden Queen Mining Company, LLC. See Note 9 for further discussion.
In addition, at March 31, 2015, we have a variable interest in a nonconsolidated VIE consisting of our senior secured term loan receivable with rights with FXCM. See Note 3 for further discussion.

Loans_To_And_Investments_In_As

Loans To And Investments In Associated Companies	3 Months Ended
	Mar. 31, 2015
Loans To And Investments In Associated Companies [Abstract]
Loans To And Investments In Associated Companies	Note 9. Loans to and Investments in Associated Companies
	A summary of loans to and investments in associated companies at March 31, 2015 and December 31, 2014 accounted for under the equity method of accounting is as follows (in thousands):
			March 31,		December 31,
			2015		2014
	Jefferies Finance, LLC	$	520,203	$	508,891
	Jefferies LoanCore LLC		301,549		258,947
	Berkadia		219,017		208,511
	Garcadia companies		170,876		167,939
	HomeFed		269,684		271,782
	Linkem S.p.A.		144,813		159,054
	Golden Queen Mining Company, LLC (1)		103,311		103,598
	Other		33,258		33,846
	Total	$	1,762,711	$	1,712,568
	(1) At March 31, 2015 and December 31, 2014, the balance reflects $33.6 million and $33.7 million, respectively, related to a noncontrolling interest.
	Income (losses) related to associated companies includes the following for the three months ended March 31, 2015 and 2014 (in thousands):
			2015			2014
	Berkadia	$	32,343		$	13,973
	Garcadia companies		15,253			11,259
	Linkem		(4,788	)		(5,836	)
	HomeFed		(2,098	)		(618	)
	Golden Queen		(287	)		–
	Other		28			1,258
	Total	$	40,451		$	20,036
	Income (losses) related to associated companies classified as Other revenues includes the following for the three months ended March 31, 2015 and 2014 (in thousands):
			2015			2014
	Jefferies Finance	$	11,311		$	17,601
	Jefferies LoanCore		9,858			2,482
	Other		(480	)		544
	Total	$	20,689		$	20,627
	Jefferies Finance
	In October 2004, Jefferies entered into an agreement with Massachusetts Mutual Life Insurance Company ("MassMutual") and Babson Capital Management LLC ("Babson Capital") to form Jefferies Finance, a joint venture entity. Jefferies Finance is a commercial finance company whose primary focus is the origination and syndication of senior secured debt to middle market and growth companies in the form of term and revolving loans. Loans are originated primarily through the investment banking efforts of Jefferies. Jefferies Finance may also originate other debt products such as second lien term, bridge and mezzanine loans, as well as related equity co-investments. Jefferies Finance also purchases syndicated loans in the secondary market.
	Jefferies and MassMutual each have equity commitments to Jefferies Finance of $600.0 million. At March 31, 2015, approximately $506.7 million of Jefferies commitment was funded. The investment commitment is scheduled to mature on March 1, 2016 with automatic one year extensions subject to a 60 day termination notice by either party.
	In addition, Jefferies and MassMutual have entered into a Secured Revolving Credit Facility, to be funded equally, to support loan underwritings by Jefferies Finance. The Secured Revolving Credit Facility bears interest based on the interest rates of the related Jefferies Finance underwritten loans and is secured by the underlying loans funded by the proceeds of the facility. The total Secured Revolving Credit Facility is $1.0 billion, comprised of committed and discretionary amounts totaling $700.0 million and $300.0 million, respectively, at March 31, 2015. Committed advances are shared equally between Jefferies and MassMutual, while discretionary advances may be funded disproportionately if so agreed between MassMutual and Jefferies. The facility is scheduled to mature on March 1, 2016 with automatic one year extensions subject to a 60 day termination notice by either party. At March 31, 2015 and December 31, 2014, $0 million and $0 million, respectively, of Jefferies $350.0 million commitment was funded.
	Jefferies engages in debt capital markets transactions with Jefferies Finance related to the originations of loans by Jefferies Finance. In connection with such transactions, Jefferies earned fees of $15.6 million and $47.6 million during the three months ended March 31, 2015 and 2014, respectively, which are recognized in Investment banking revenues in the Consolidated Statements of Operations. In addition, Jefferies paid fees to Jefferies Finance in respect of certain loans originated by Jefferies Finance of $.7 million and $4.3 million during the three months ended March 31, 2015 and 2014, respectively, which are recognized within Selling, general and other expenses in the Consolidated Statements of Operations.
	During the three months ended March 31, 2015, Jefferies acted as placement agent in connection with a CLO managed by Jefferies Finance, for which Jefferies recognized fees of $.4 million, which are included in Investment banking revenues in the Consolidated Statement of Operations. At March 31, 2015 and December 31, 2014, Jefferies held securities issued by the CLOs managed by Jefferies Finance, which are included within Trading assets, and provided a guarantee, whereby Jefferies is required to make payments to a CLO in the event Jefferies Finance is unable to meet its obligation to the CLO. Additionally, Jefferies has entered into a derivative contract with Jefferies Finance whose underlying is based on certain securities issued by the CLO. There were no significant revenues recognized by Jefferies in connection with its roles related to the execution of the CLO.
	Under a service agreement, Jefferies charged Jefferies Finance $27.8 million and $21.7 million for services provided during the three months ended March 31, 2015 and 2014, respectively. Receivables from Jefferies Finance, included within Other assets in the Consolidated Statements of Financial Condition, were $15.5 million and $41.5 million at March 31, 2015 and December 31, 2014, respectively.
	Jefferies LoanCore
	In February 2011, Jefferies entered into a joint venture agreement with the Government of Singapore Investment Corporation and LoanCore, LLC and formed Jefferies LoanCore, a commercial real estate finance company. Jefferies LoanCore originates and purchases commercial real estate loans throughout the U.S. with the support of the investment banking and securitization capabilities of Jefferies and the real estate and mortgage investment expertise of the Government of Singapore Investment Corporation and LoanCore, LLC. Jefferies LoanCore has aggregate equity commitments of $600.0 million. At March 31, 2015 and December 31, 2014, Jefferies had funded $237.0 million and $200.9 million, respectively, of its $291.0 million equity commitment and has a 48.5% voting interest in Jefferies LoanCore.
	Berkadia
	Berkadia Commercial Mortgage LLC is a commercial mortgage banking and servicing joint venture formed in 2009 with Berkshire Hathaway. We and Berkshire Hathaway each contributed $217.2 million of equity capital to the joint venture and each have a 50% equity interest in Berkadia. Through March 31, 2015, cumulative cash distributions received from this investment aggregated $322.5 million. Berkadia originates commercial/multifamily real estate loans that are sold to U.S. government agencies, and originates and brokers commercial mortgage loans which are not part of government agency programs. Berkadia is a servicer of commercial real estate loans in the U.S., performing primary, master and special servicing functions for U.S. government agency programs, commercial mortgage-backed securities transactions, banks, insurance companies and other financial institutions.
	Berkadia uses all of the proceeds from the commercial paper sales of an affiliate of Berkadia to fund new mortgage loans, servicer advances, investments and other working capital requirements. Repayment of the commercial paper is supported by a $2.5 billion surety policy issued by a Berkshire Hathaway insurance subsidiary and corporate guaranty, and we have agreed to reimburse Berkshire Hathaway for one-half of any losses incurred thereunder. As of March 31, 2015, the aggregate amount of commercial paper outstanding was $2.47 billion.
	Linkem
	We have acquired approximately 42% of the common shares of Linkem, a fixed wireless broadband services provider in Italy, for aggregate cash consideration of $142.9 million. In addition, we have purchased 5% convertible notes issued by Linkem for 38
	$101.0 million (€78.9 million principal amount, including interest in kind) which if converted, would increase our ownership to approximately 55% of Linkem's common equity. The excess of our investment in Linkem's common shares over our share of underlying book value is being amortized to expense over 12 years.
	HomeFed
	At March 31, 2015, we own 9,974,226 shares of HomeFed's common stock, representing approximately 65% of HomeFed's outstanding common shares; however, we have agreed to limit our voting rights such that we will not be able to vote more than 45% of HomeFed's total voting securities voting on any matter, assuming all HomeFed shares not owned by us are voted. HomeFed is engaged, directly and through subsidiaries, in the investment in and development of real estate projects. HomeFed is a public company traded on the NASD OTC Bulletin Board (Symbol: HOFD). As a result of a 1998 distribution to all of our shareholders, approximately 4.8% of HomeFed is beneficially owned by our Chairman at March 31, 2015. Our Chairman also serves as HomeFed's Chairman, and our President is a Director of HomeFed.
	During 2014, we sold to HomeFed substantially all of our real estate properties and operations, our interest in Brooklyn Renaissance Plaza ("BRP") and cash of approximately $14.0 million, in exchange for 7,500,000 newly issued unregistered HomeFed common shares. Under GAAP, we are not permitted to immediately recognize any gain on real estate sale transactions in which the seller does not receive cash; accordingly, the gain on sale of approximately $36.1 million was deferred and is being recognized into income over time.
	Since we do not control HomeFed, our investment in HomeFed is accounted for as an investment in an associated company. We have also entered into a stockholders agreement that will limit our ability to increase our interest in HomeFed or dispose of our interest in HomeFed. We have a registration rights agreement with HomeFed that covers all of our HomeFed shares.
	Golden Queen Mining Company
	During 2014, we invested $70.9 million, net in cash in a limited liability company (Gauss LLC) to partner with the Clay family and Golden Queen Mining Co. Ltd., to jointly fund, develop and operate the Soledad Mountain gold and silver mine project. Previously 100% owned by Golden Queen Mining Co. Ltd., the project is a fully-permitted, open pit, heap leach gold and silver project located in Kern County, California. Construction has started on site and commissioning is planned for late 2015. In exchange for a noncontrolling ownership interest in Gauss LLC, the Clay family contributed $34.1 million, net in cash. Gauss LLC invested both our and the Clay family's net contributions totaling $105 million to the joint venture, Golden Queen Mining Company, LLC, in exchange for a 50% ownership interest. Golden Queen Mining Co. Ltd. contributed the Soledad Mountain project to the joint venture in exchange for the other 50% interest.
	As a result of our consolidating Gauss LLC, our Loans to and investments in associated companies reflects Gauss LLC's net investment of $105 million in the joint venture, which includes both the amount we contributed and the amount contributed by the Clay family. The joint venture, Golden Queen Mining Company, LLC, is considered a VIE as the voting rights of the investors are not proportional to their obligations to absorb the expected losses and their rights to receive the expected residual returns, given the provision of services to the joint venture by Golden Queen Mining Co. Ltd. Golden Queen Mining Co. Ltd. has entered into an agreement with the joint venture for the provision of executive officers, financial, managerial, administrative and other services, and office space and equipment. We have determined that we are not the primary beneficiary of the joint venture and are therefore not consolidating its results.
	We have committed to invest during the nine months after our initial investment up to an additional approximately $27 million to fully develop the project.
	Our maximum exposure to loss as a result of our involvement with the joint venture is limited to our investment and the commitment discussed above.

Financial_Statement_Offsetting

Financial Statement Offsetting	3 Months Ended
	Mar. 31, 2015
Financial Statement Offsetting [Abstract]
Financial Statement Offsetting	Note 10. Financial Statement Offsetting
	In connection with Jefferies derivative activities and securities financing activities, Jefferies may enter into master netting agreements and collateral arrangements with counterparties. Generally, transactions are executed under standard industry agreements, including, but not limited to: derivative transactions – ISDA master netting agreements; securities lending transactions – master securities lending agreements; and repurchase transactions – master repurchase agreements. A master agreement creates a single contract under which all transactions between two counterparties are executed allowing for trade aggregation and a single net payment obligation. Master agreements provide protection in bankruptcy in certain circumstances and, where legally enforceable, enable receivables and payables with the same counterparty to be settled or otherwise eliminated by applying amounts due to a counterparty against all or a portion of an amount due from the counterparty or a third party. In addition, Jefferies may enter into customized bilateral trading agreements and other customer agreements that provide for the netting of receivables and payables with a given counterparty as a single net obligation.
	Under Jefferies derivative ISDA master netting agreements, Jefferies typically will also execute credit support annexes, which provide for collateral, either in the form of cash or securities, to be posted by or paid to a counterparty based on the fair value of the derivative receivable or payable based on the rates and parameters established in the credit support annex. In the event of the counterparty's default, provisions of the master agreement permit acceleration and termination of all outstanding transactions covered by the agreement such that a single amount is owed by, or to, the non-defaulting party. In addition, any collateral posted can be applied to the net obligations, with any excess returned; and the collateralized party has a right to liquidate the collateral. Any residual claim after netting is treated along with other unsecured claims in bankruptcy court.
	The conditions supporting the legal right of offset may vary from one legal jurisdiction to another and the enforceability of master netting agreements and bankruptcy laws in certain countries or in certain industries is not free from doubt. The right of offset is dependent both on contract law under the governing arrangement and consistency with the bankruptcy laws of the jurisdiction where the counterparty is located. Industry legal opinions with respect to the enforceability of certain standard provisions in respective jurisdictions are relied upon as a part of managing credit risk. Master netting agreements are a critical component of Jefferies risk management processes as part of reducing counterparty credit risk and managing liquidity risk.
	Jefferies is also a party to clearing agreements with various central clearing parties. Under these arrangements, the central clearing counterparty facilitates settlement between counterparties based on the net payable owed or receivable due and, with respect to daily settlement, cash is generally only required to be deposited to the extent of the net amount. In the event of default, a net termination amount is determined based on the market values of all outstanding positions and the clearing organization or clearing member provides for the liquidation and settlement of the net termination amount among all counterparties to the open repurchase and/or securities lending transactions.
	The following table provides information regarding derivative contracts, repurchase agreements and securities borrowing and lending arrangements that are recognized in the Consolidated Statements of Financial Condition and 1) the extent to which, under enforceable master netting arrangements, such balances are presented net in the Consolidated Statements of Financial Condition as appropriate under GAAP and 2) the extent to which other rights of setoff associated with these arrangements exist and could have an effect on our consolidated financial position.
					Netting in			Net Amounts in
					Consolidated			Consolidated		Additional
					Statement of			Statement of		Amounts
			Gross		Financial			Financial		Available for			Available
	(In thousands)		Amounts		Condition			Condition		Setoff (1)			Collateral (2)			Net Amount (3)
	Assets at March 31, 2015
	Derivative contracts	$	5,226,625	$	(4,729,533	)	$	497,092	$	–		$	–		$	497,092
	Securities borrowing arrangements	$	6,566,376	$	–		$	6,566,376	$	(526,142	)	$	(766,832	)	$	5,273,402
	Reverse repurchase agreements	$	11,109,009	$	(7,363,321	)	$	3,745,688	$	(236,325	)	$	(3,450,577	)	$	58,786
	Liabilities at March 31, 2015
	Derivative contracts	$	5,133,092	$	(4,810,751	)	$	322,341	$	–		$	–		$	322,341
	Securities lending arrangements	$	3,173,512	$	–		$	3,173,512	$	(526,142	)	$	(2,616,154	)	$	31,216
	Repurchase agreements	$	18,686,688	$	(7,363,321	)	$	11,323,367	$	(236,325	)	$	(10,039,131	)	$	1,047,911
	Assets at December 31, 2014
	Derivative contracts	$	5,165,613	$	(4,759,345	)	$	406,268	$	–		$	–		$	406,268
	Securities borrowing arrangements	$	6,853,103	$	–		$	6,853,103	$	(680,222	)	$	(1,274,196	)	$	4,898,685
	Reverse repurchase agreements	$	14,059,133	$	(10,132,275	)	$	3,926,858	$	(634,568	)	$	(3,248,817	)	$	43,473
	Liabilities at December 31, 2014
	Derivative contracts	$	5,220,133	$	(4,856,618	)	$	363,515	$	–		$	–		$	363,515
	Securities lending arrangements	$	2,598,487	$	–		$	2,598,487	$	(680,222	)	$	(1,883,140	)	$	35,125
	Repurchase agreements	$	20,804,432	$	(10,132,275	)	$	10,672,157	$	(634,568	)	$	(8,810,770	)	$	1,226,819
	(1) Under master netting agreements with our counterparties, we have the legal right of offset with a counterparty, which incorporates all of the counterparty's outstanding rights and obligations under the arrangement. These balances reflect additional credit risk mitigation that is available by counterparty in the event of a counterparty's default, but which are not netted in the balance sheet because other provisions of GAAP are not met. Further, for derivative assets and liabilities, amounts netted include cash collateral paid or received.
	(2) Includes securities received or paid under collateral arrangements with counterparties that could be liquidated in the event of a counterparty default and thus offset against a counterparty's rights and obligations under the respective repurchase agreements or securities borrowing or lending arrangements.
	(3) At March 31, 2015, amounts include $5,241.5 million of securities borrowing arrangements, for which we have received securities collateral of $5,093.8 million, and $1,038.8 million of repurchase agreements, for which we have pledged securities collateral of $1,073.4 million, which are subject to master netting agreements but we have not yet determined the agreements to be legally enforceable. At December 31, 2014, amounts include $4,847.4 million of securities borrowing arrangements, for which we have received securities collateral of $4,694.0 million, and $1,201.9 million of repurchase agreements, for which we have pledged securities collateral of $1,238.4 million, which are subject to master netting agreements but we have not yet determined the agreements to be legally enforceable.

Intangible_Assets_Net_And_Good

Intangible Assets, Net And Goodwill	3 Months Ended
	Mar. 31, 2015
Intangible Assets, Net And Goodwill [Abstract]
Intangible Assets, Net And Goodwill	Note 11. Intangible Assets, Net and Goodwill
	A summary of intangible assets, net and goodwill at March 31, 2015 and December 31, 2014 is as follows (in thousands):
			March 31,		December 31,
			2015		2014
	Indefinite-lived intangibles:
	Exchange and clearing organization membership interests and registrations	$	14,501	$	14,528
	Amortizable intangibles:
	Customer and other relationships, net of accumulated amortization of
	$165,060 and $155,548		483,408		493,501
	Trademarks and tradename, net of accumulated amortization of $51,254
	and $47,101		343,459		347,883
	Supply contracts, net of accumulated amortization of $32,997 and $30,433		116,998		119,562
	Other, net of accumulated amortization of $4,808 and $4,703		2,795		2,900
	Total intangible assets, net		961,161		978,374
	Goodwill:
	National Beef		14,991		14,991
	Jefferies		1,717,595		1,718,847
	Other operations		8,551		8,551
	Total goodwill		1,741,137		1,742,389
	Total intangible assets, net and goodwill	$	2,702,298	$	2,720,763
	Amortization expense on intangible assets was $16.3 million and $16.6 million for the three months ended March 31, 2015 and 2014, respectively. The estimated aggregate future amortization expense for the intangible assets for each of the next five years is as follows: 2015 (for the remaining nine months) - $47.6 million; 2016 - $63.0 million; 2017 - $63.1 million; 2018 -$63.3 million; and 2019 - $63.1 million.

Inventory

Inventory	3 Months Ended
	Mar. 31, 2015
Inventory [Abstract]
Inventory	Note 12. Inventory
	A summary of inventory at March 31, 2015 and December 31, 2014 which is classified as Other assets is as follows (in thousands):
			March 31,		December 31,
			2015		2014
	Finished goods	$	364,875	$	343,959
	Work in process		40,773		40,951
	Raw materials, supplies and other		39,184		37,993
		$	444,832	$	422,903

ShortTerm_Borrowings

Short-Term Borrowings	3 Months Ended
	Mar. 31, 2015
Short-Term Borrowings [Abstract]
Short-Term Borrowings	Note 13. Short-Term Borrowings
	Short-term borrowings represent Jefferies bank loans that are payable on demand and generally bear interest at a spread over the federal funds rate. Unsecured bank loans are typically overnight loans used to finance trading assets or clearing related balances, but are not part of Jefferies systemic funding model. At March 31, 2015 and December 31, 2014, $412.0 million and $12.0 million, respectively, was outstanding. At March 31, 2015, the interest rate on short-term borrowings outstanding is 1.34% per annum.

LongTerm_Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2015
Long-Term Debt [Abstract]
Long-Term Debt	Note 14. Long-Term Debt
	The principal amount (net of unamortized discounts and premiums), stated interest rate and maturity date of outstanding debt at March 31, 2015 and December 31, 2014 are as follows (dollars in thousands):
			March 31,		December 31,
			2015		2014
	Parent Company Debt:
	Senior Notes:
	8.125% Senior Notes due September 15, 2015, $458,641 principal	$	458,040	$	457,723
	5.50% Senior Notes due October 18, 2023, $750,000 principal		740,953		740,748
	6.625% Senior Notes due October 23, 2043, $250,000 principal		247,000		246,991
	Total long-term debt – Parent Company		1,445,993		1,445,462
	Subsidiary Debt (non-recourse to Parent Company):
	Jefferies:
	3.875% Senior Notes, due November 9, 2015, $500,000 principal		505,851		507,944
	5.5% Senior Notes, due March 15, 2016, $350,000 principal		360,702		363,229
	5.125% Senior Notes, due April 13, 2018, $800,000 principal		839,383		842,359
	8.5% Senior Notes, due July 15, 2019, $700,000 principal		826,229		832,797
	2.375% Euro Senior Notes, due May 20, 2020, $559,850 principal		558,601		620,725
	6.875% Senior Notes, due April 15, 2021, $750,000 principal		849,568		853,091
	2.25% Euro Medium Term Notes, due July 13, 2022, $4,479 principal		3,956		4,379
	5.125% Senior Notes, due January 20, 2023, $600,000 principal		622,716		623,311
	6.45% Senior Debentures, due June 8, 2027, $350,000 principal		381,073		381,515
	3.875% Convertible Senior Debentures, due November 1, 2029,
	$345,000 principal		348,276		348,568
	6.25% Senior Debentures, due January 15, 2036, $500,000 principal		512,969		513,046
	6.50% Senior Notes, due January 20, 2043, $400,000 principal		421,885		421,960
	Secured credit facility, due June 26, 2017		205,000		170,000
	National Beef Term Loan		336,250		345,000
	National Beef Revolving Credit Facility		181,916		135,144
	Other		158,415		119,399
	Total long-term debt – subsidiaries		7,112,790		7,082,467
	Long-term debt	$	8,558,783	$	8,527,929
	Subsidiary Debt:
	Jefferies 3.875% Convertible Senior Debentures due 2029 are convertible into our common shares; each $1,000 are convertible into 22.2523 common shares (equivalent to a conversion price of approximately $44.94). The debentures are convertible at the holders' option any time beginning on August 1, 2029 and convertible at any time if: 1) our common stock price is greater than or equal to 130% of the conversion price for at least 20 trading days in a period of 30 consecutive trading days; 2) if the trading price per debenture is less than 95% of the price of our common stock times the conversion ratio for any 10 consecutive trading days; 3) if the debentures are called for redemption; or 4) upon the occurrence of specific corporate actions. The debentures may be redeemed for par, plus accrued interest, on or after November 1, 2012 if the price of our common stock is greater than 130% of the conversion price for at least 20 days in a period of 30 consecutive trading days and we may redeem the debentures for par, plus accrued interest, at our election any time on or after November 1, 2017. Holders may require us to repurchase the debentures for par, plus accrued interest, on November 1, 2017, 2019 and 2024. In addition to ordinary interest, commencing November 1, 2017, contingent interest will accrue at 0.375% if the average trading price of a debenture for 5 trading days ending on and including the third trading day immediately preceding a six-month interest period equals or exceeds $1,200 per $1,000 debenture.
	At March 31, 2015, Jefferies has a committed senior secured revolving credit facility ("Jefferies Credit Facility") with a group of commercial banks in U.S. dollars, Euros and Sterling, in an aggregate committed amount of $750.0 million with availability subject to one or more borrowing bases. The Jefferies Credit Facility contains certain financial covenants, including, but not limited to, restrictions on future indebtedness of Jefferies subsidiaries, minimum tangible net worth and liquidity requirements amounts and minimum capital requirements. Interest is based on, in the case of U.S. dollar borrowings, the Federal funds rate or the London Interbank Offered Rate or, in the case of non-U.S. dollar borrowings, is based on the London Interbank Offered Rate. The obligations of each borrower under the Credit Facility are secured by substantially all the assets of such borrower, but none of the borrowers is responsible for any obligations of any other borrower. At March 31, 2015, borrowings under the Jefferies Credit Facility were denominated in U.S. dollars and Jefferies is in compliance with debt covenants under the Jefferies Credit Facility.
	At March 31, 2015, National Beef's credit facility consisted of a $375.0 million term loan and a revolving credit facility of $300.0 million, which matures in October 2018. In April 2015, National Beef increased its revolving credit facility to $375.0 million. The term loan and the revolving credit facility bear interest at the Base Rate or the LIBOR Rate (as defined in the credit facility), plus a margin ranging from 0.75% to 2.75% depending upon certain financial ratios and the rate selected. At March 31, 2015, the interest rate on the outstanding term loan was 2.9% and the interest rate on the outstanding revolving credit facility was 2.9%. The credit facility contains a minimum tangible net worth covenant; at March 31, 2015, National Beef met this covenant. The credit facility is secured by a first priority lien on substantially all of the assets of National Beef and its subsidiaries.
	Borrowings under the revolving credit facility are available for National Beef's working capital requirements, capital expenditures and other general corporate purposes. Unused capacity under the facility can also be used to issue letters of credit; letters of credit aggregating $20.1 million were outstanding at March 31, 2015. Amounts available under the revolver are subject to a borrowing base calculation primarily comprised of receivable and inventory balances. At March 31, 2015, after deducting outstanding amounts and issued letters of credit, $98.0 million of the unused revolver was available to National Beef.

Mezzanine_Equity

Mezzanine Equity	3 Months Ended
	Mar. 31, 2015
Mezzanine Equity [Abstract]
Mezzanine Equity	Note 15. Mezzanine Equity
	Redeemable Noncontrolling Interests
	Redeemable noncontrolling interests primarily relate to National Beef and are held by its minority owners, principally USPB, NBPCo Holdings and the chief executive officer of National Beef. The holders of these interests share in the profits and losses of National Beef on a pro rata basis with us. However, the minority owners have the right to require us to purchase their interests under certain specified circumstances at fair value (put rights), and we also have the right to purchase their interests under certain specified circumstances at fair value (call rights). Each of the holders of the put rights has the right to make an election that requires us to purchase up to one-third of their interests on December 30, 2016, one-third on December 30, 2018, and the remainder on December 30, 2021. In addition, USPB may elect to exercise their put rights following the termination of the cattle supply agreement, and the chief executive officer following the termination of his employment.
	Our call rights with respect to USPB may be exercised following the termination of the cattle supply agreement or after USPB's ownership interest is less than 20% of their interest held at the time we acquired National Beef. Our call rights with respect to other members may be exercised after the ten year anniversary of our acquisition of National Beef if such member's ownership interest is less than 50% of the interest held at the time we acquired National Beef. Additionally, we may acquire the chief executive officer's interest following the termination of his employment.
	Redeemable noncontrolling interests in National Beef are reflected in the Consolidated Statements of Financial Condition at fair value. The following table reconciles National Beef's redeemable noncontrolling interests activity during the three months ended March 31, 2015 and 2014 (in thousands):
			2015			2014
	As of January 1,	$	184,333		$	241,075
	Loss allocated to redeemable noncontrolling
	interests		(7,059	)		(5,939	)
	Decrease in fair value of redeemable noncontrolling
	interests credited to additional paid-in capital		(11,033	)		(755	)
	Balance, March 31,	$	166,241		$	234,381
	At acquisition, we prepared a projection of future cash flows of National Beef, which was used along with other information to allocate the purchase price to National Beef's individual assets and liabilities. At March 31, 2015, we calculated the fair value of the redeemable noncontrolling interests by updating our estimate of future cash flows, as well as considering other market comparable information deemed appropriate. The projected future cash flows consider estimated revenue growth, cost of sales changes, capital expenditures and other unobservable inputs. However, the most significant unobservable inputs affecting the estimate of fair value are the discount rate (13.0%) and the terminal growth rate (2.0%) used to calculate the capitalization rate of the terminal value.
	The table below is a sensitivity analysis which shows the fair value of the redeemable noncontrolling interests using the assumed discount and the terminal growth rates and fair values under different rate assumptions as of March 31, 2015 (dollars in millions):
		Discount Rates
	Terminal Growth Rates		12.75%		13.00%		13.25%
	1.75%	$	170	$	164.2	$	158.6
	2.00%	$	172.2	$	166.2	$	160.5
	2.25%	$	174.5	$	168.4	$	162.5
	The projection of future cash flows is updated with input from National Beef personnel. The estimate is reviewed by personnel at our corporate office as part of the normal process for the preparation of our quarterly and annual financial statements.
	At March 31, 2015 and December 31, 2014, redeemable noncontrolling interests also include the noncontrolling interest in a business acquired by Conwed of $2.3 million and $2.4 million, respectively.
	Mandatorily Redeemable Convertible Preferred Shares
	In connection with our acquisition of Jefferies in March 2013, we issued a new series of 3.25% Cumulative Convertible Preferred Shares ("Preferred Shares") ($125.0 million at mandatory redemption value) in exchange for Jefferies outstanding 3.25% Series A-1 Cumulative Convertible Preferred Stock. The Preferred Shares have a 3.25% annual, cumulative cash dividend and are currently convertible into 4,162,200 common shares, an effective conversion price of $30.03 per share. The Preferred Shares are callable beginning in 2023 at a price of $1,000 per share plus accrued interest and are mandatorily redeemable in 2038.

Common_Shares_And_Compensation

Common Shares And Compensation Plans	3 Months Ended
	Mar. 31, 2015
Common Shares And Compensation Plans [Abstract]
Common Shares And Compensation Plans	Note 16. Common Shares and Compensation Plans
	Prior to the acquisition of Jefferies, we had two share-based compensation plans: a fixed stock option plan and a senior executive warrant plan. The fixed stock option plan provides for the issuance of stock options and stock appreciation rights to non-employee directors and certain employees at not less than the fair market value of the underlying stock at the date of grant. Options granted to employees under this plan are intended to qualify as incentive stock options to the extent permitted under the Internal Revenue Code and become exercisable in five equal annual instalments starting one year from date of grant. Options granted to non-employee directors become exercisable in four equal annual instalments starting one year from date of grant. No stock appreciation rights have been granted. At March 31, 2015, 5,233,906 of our common shares were reserved for stock options and warrants.
	Compensation and benefits expense included $32.8 million and $38.2 million for the three months ended March 31, 2015 and 2014, respectively, for share-based compensation expense relating to grants made under our share-based compensation plans. Total compensation cost includes the amortization of sign-on, retention and senior executive awards, less forfeitures and clawbacks. The total tax benefit recognized in results of operations related to share-based compensation expenses was $11.9 million and $14.0 million for the three months ended March 31, 2015 and 2014, respectively. As of March 31, 2015, total unrecognized compensation cost related to nonvested share-based compensation plans was $88.2 million; this cost is expected to be recognized over a weighted-average period of 1.7 years.
	The net tax detriment related to share-based compensation plans recognized in additional paid-in capital was $5.3 million during the three months ended March 31, 2015 and was not significant during the 2014 period. Cash flows resulting from tax deductions in excess of the grant date fair value of share-based awards are included in cash flows from financing activities; accordingly, we reflected the excess tax benefit related to share-based compensation in cash flows from financing activities. Such amounts for the three months ended March 31, 2015 and 2014 were not significant.
	At March 31, 2015, there were 2,572,000 shares of restricted stock outstanding with future service required, 4,065,000 RSUs outstanding with future service required, 8,563,000 RSUs outstanding with no future service required and 866,000 shares issuable under other plans. Excluding shares issuable pursuant to outstanding stock options and warrants, the maximum potential increase to common shares outstanding resulting from these outstanding awards is 13,494,000.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	3 Months Ended
	Mar. 31, 2015
Accumulated Other Comprehensive Income [Abstract]
Accumulated Other Comprehensive Income	Note 17. Accumulated Other Comprehensive Income
	Activity in accumulated other comprehensive income is reflected in the Consolidated Statements of Comprehensive Income (Loss) and Consolidated Statements of Changes in Equity but not in the Consolidated Statements of Operations. A summary of accumulated other comprehensive income, net of taxes at March 31, 2015 and December 31, 2014 is as follows (in thousands):
			March 31,			December 31,
			2015			2014
	Net unrealized gains on available for sale securities	$	571,170		$	577,588
	Net unrealized foreign exchange losses		(41,492	)		(26,771	)
	Net minimum pension liability		(102,560	)		(103,735	)
		$	427,118		$	447,082
	For the three months ended March 31, 2015 and 2014, significant amounts reclassified out of accumulated other comprehensive income to net income are as follows (in thousands):
	Details about Accumulated Other		Amount Reclassified from					Affected Line Item in the
	Comprehensive Income		Accumulated Other					Consolidated Statements
	Components		Comprehensive Income					of Operations
			2015			2014
	Net unrealized gains (losses) on available for							Net realized securities gains
	sale securities, net of income tax provision
	(benefit) of $2,944 and $(488)	$	5,303		$	(878	)
	Amortization of defined benefit pension							Compensation and benefits, which
	plan actuarial gains (losses), net of							includes pension expense. See the
	income tax benefit of $(653)							pension footnote for information
	and $(422)		(1,175	)		(760	)	on this component.
	Total reclassifications for the period,
	net of tax	$	4,128		$	(1,638	)

Pension_Plans_And_Postretireme

Pension Plans And Postretirement Benefits	3 Months Ended
	Mar. 31, 2015
Pension Plans And Postretirement Benefits [Abstract]
Pension Plans And Postretirement Benefits	Note 18. Pension Plans and Postretirement Benefits
	The following table summarizes the components of net periodic pension cost charged to operations for the three months ended March 31, 2015 and 2014 (in thousands):
			2015			2014
	Components of net periodic pension cost:
	Interest cost	$	3,476		$	3,774
	Service cost		–			11
	Expected return on plan assets		(2,690	)		(2,536	)
	Actuarial losses		1,912			1,208
	Net periodic pension cost	$	2,698		$	2,457
	No employer contributions were paid during the three months ended March 31, 2015.
	Other
	We have defined contribution pension plans covering certain employees. Contributions and costs are a percent of each covered employee's salary. Amounts charged to expense related to such plans were not significant for the 2015 and 2014 periods.
	We provide certain health care and other benefits to certain retired employees under plans which are currently unfunded. We pay the cost of postretirement benefits as they are incurred. Accumulated postretirement benefit obligations and amounts recognized in the consolidated statements of operations and in accumulated other comprehensive income (loss) were not significant.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2015
Income Taxes [Abstract]
Income Taxes	Note 19. Income Taxes
	The aggregate amount of unrecognized tax benefits related to uncertain tax positions at March 31, 2015 was $178.4 million (including $37.5 million for interest), of which $148.6 million was related to Jefferies. If recognized, such amounts would lower our effective tax rate.
	The statute of limitations with respect to our federal income tax returns has expired for all years through 2010. Our New York State and New York City income tax returns are currently being audited for the 2009 to 2011 period. Prior to becoming a wholly-owned subsidiary, Jefferies filed a consolidated U.S. federal income tax return with its qualifying subsidiaries and was subject to income tax in various states, municipalities and foreign jurisdictions. Jefferies is currently under examination by the Internal Revenue Service and other major tax jurisdictions. The statute of limitations with respect to Jefferies federal income tax returns has expired for all years through 2005.
	We do not expect that resolution of these examinations will have a significant effect on our consolidated financial position, but could have a significant impact on the consolidated results of operations for the period in which resolution occurs.
	For the three months ended March 31, 2015 and 2014, the provision for income taxes includes $8.9 million and $15.1 million, respectively, for state income taxes and $2.7 million and $6.0 million, respectively, for foreign income taxes.

Earnings_Loss_Per_Common_Share

Earnings (Loss) Per Common Share	3 Months Ended
	Mar. 31, 2015
Earnings (Loss) Per Common Share [Abstract]
Earnings (Loss) Per Common Share	Note 20. Earnings (Loss) Per Common Share
	Basic and diluted earnings (loss) per share amounts were calculated by dividing net income (loss) by the weighted average number of common shares outstanding. The numerators and denominators used to calculate basic and diluted earnings (loss) per share are as follows for the three months ended March 31, 2015 and 2014 (in thousands):
			2015			2014
	Numerator for earnings (loss) per share:
	Net income attributable to Leucadia
	National Corporation common shareholders	$	380,759		$	94,316
	Allocation of earnings to participating securities (1)		(7,086	)		(2,397	)
	Net income attributable to Leucadia
	National Corporation common shareholders for
	basic earnings (loss) per share		373,673			91,919
	Adjustment to allocation of earnings to participating
	securities related to diluted shares (1)		54			–
	Mandatorily redeemable convertible preferred share
	dividends		1,016			1,016
	Interest on 3.75% Convertible Notes		–			640
	Net income attributable to Leucadia
	National Corporation common shareholders for
	diluted earnings (loss) per share	$	374,743		$	93,575
	Denominator for earnings (loss) per share:
	Denominator for basic earnings (loss) per share –
	weighted average shares		373,541			368,487
	Stock options		10			101
	Warrants		–			–
	Mandatorily redeemable convertible preferred shares		4,162			4,162
	3.875% Convertible Senior Debentures		–			–
	3.75% Convertible Notes		–			4,598
	Denominator for diluted earnings (loss) per share		377,713			377,348
	(1) Represents dividends declared during the period on participating securities plus an allocation of undistributed earnings to participating securities. Net losses are not allocated to participating securities. Participating securities represent restricted stock and RSUs for which requisite service has not yet been rendered and amounted to weighted average shares of 7,114,000 and 9,704,400 for the three months ended March 31, 2015 and 2014, respectively.
	Dividends declared on participating securities during the three months ended March 31, 2015 and 2014 were $0.4 million and $0.6 million, respectively. Undistributed earnings are allocated to participating securities based upon their right to share in earnings if all earnings for the period had been distributed.
	Options to purchase 1,311,000 and 773,000 weighted-average shares of common stock were outstanding during the three months ended March 31, 2015 and 2014, respectively, but were not included in the computation of diluted per share amounts as the effect was antidilutive.
	For each period in the table above, the denominator for diluted earnings (loss) per share does not include weighted-average common shares of 4,000,000 related to outstanding warrants to purchase common shares at $33.33 per share, as the effect was antidilutive.
	For the three months ended March 31, 2015 and 2014, shares related to the 3.875% Convertible Senior Debentures were not included in the computation of diluted per share amounts as the conversion price exceeded the average market price.

Commitments_Contingencies_And_

Commitments, Contingencies And Guarantees	3 Months Ended
	Mar. 31, 2015
Commitments, Contingencies And Guarantees [Abstract]
Commitments, Contingencies And Guarantees	Note 21. Commitments, Contingencies and Guarantees
	Commitments
	The following table summarizes Jefferies commitments associated with certain business activities (in millions):
		Expected Maturity Date
							2017		2019		2021
							and		and		and		Maximum
			2015		2016		2018		2020		Later		Payout
	Equity commitments (1)	$	–	$	9.2	$	0.8	$	–	$	171.8	$	181.8
	Loan commitments (1)		44.6		421.7		188.9		48.3		–		703.5
	Mortgage-related and other purchase
	commitments		1,123.10		1,315.60		126.2		–		–		2,564.90
	Forward starting reverse repos and repos		2,034.90		–		–		–		–		2,034.90
	Other unfunded commitments (1)		30		–		–		–		21.9		51.9
		$	3,232.60	$	1,746.50	$	315.9	$	48.3	$	193.7	$	5,537.00
	(1) Equity, loan and other unfunded commitments are presented by contractual maturity date. The amounts are however available on demand.
	The table below presents Jefferies credit exposure from loan commitments, including funded amounts, summarized by period of expiration as of March 31, 2015. Credit exposure is based on the external credit ratings of the underlying or referenced assets of the loan commitments. Since commitments associated with these business activities may expire unused, they do not necessarily reflect the actual future cash funding requirements (in millions):
									Total		Corporate		Corporate
							Greater		Corporate		Lending		Lending
			0 - 12		5-Jan		Than		Lending		Exposure at		Commitments
	Credit Ratings		Months		Years		5 Years		Exposure (1)		Fair Value (2)		-3
	Non-investment grade	$	–	$	167.6	$	–	$	167.6	$	2.8	$	164.8
	Unrated		128		643		–		771		232.3		538.7
	Total	$	128	$	810.6	$	–	$	938.6	$	235.1	$	703.5
	(1) Total corporate lending exposure represents the potential loss assuming the fair value of funded loans and lending commitments were zero.
	(2) The corporate lending exposure at fair value includes $262.0 million of funded loans included in Trading assets and a $26.9 million net liability related to lending commitments recorded in Trading liabilities in the Consolidated Statement of Financial Condition as of March 31, 2015.
	(3) Amounts represent the notional amount of unfunded lending commitments.
	Equity Commitments. Equity commitments include commitments to invest in Jefferies joint ventures, Jefferies Finance and Jefferies LoanCore, and commitments to invest in private equity funds and in Jefferies Capital Partners, LLC, the manager of the private equity funds, which are managed by a team led by Brian P. Friedman, our President and a Director. As of March 31, 2015, Jefferies outstanding commitments relating to Jefferies Capital Partners, LLC and its private equity funds were $30.0 million.
	See Note 9 for additional information regarding Jefferies investments in Jefferies Finance and Jefferies LoanCore.
	In August 2014, we and Solomon Kumin established Folger Hill Asset Management LLC ("Folger Hill"); we committed to provide Folger Hill with a 3-year, $20 million revolving credit facility to fund its start-up and initial operating expenses. As of March 31, 2015, $8.3 million has been provided to Folger Hill under the revolving credit facility.
	Additionally, as of March 31, 2015, Jefferies had other equity commitments to invest up to $4.5 million in various other investments.
	Loan Commitments. From time to time Jefferies makes commitments to extend credit to investment banking and other clients in loan syndication, acquisition finance and securities transactions and to SPE sponsors in connection with the funding of CLO and other asset-backed transactions. These commitments and any related drawdowns of these facilities typically have fixed maturity dates and are contingent on certain representations, warranties and contractual conditions applicable to the borrower. As of March 31, 2015, Jefferies has $353.5 million of outstanding loan commitments to clients.
	Loan commitments outstanding as of March 31, 2015, also include Jefferies portion of the outstanding secured revolving credit facility provided to Jefferies Finance, to support loan underwritings by Jefferies Finance.
	Mortgage-Related and Other Purchase Commitments. Jefferies enters into forward contracts to purchase mortgage participation certificates, mortgage-backed securities and consumer loans. The mortgage participation certificates evidence interests in mortgage loans insured by the Federal Housing Administration and the mortgage-backed securities are insured or guaranteed by the FNMA (Fannie Mae), the Federal Home Loan Mortgage Corporation (Freddie Mac) or the GNMA (Ginnie Mae). Jefferies frequently securitizes the mortgage participation certificates and mortgage-backed securities. The fair value of mortgage-related and other purchase commitments recorded in the Consolidated Statement of Financial Condition at March 31, 2015 was $154.9 million.
	Forward Starting Reverse Repos and Repos. Jefferies enters into commitments to take possession of securities with agreements to resell on a forward starting basis and to sell securities with agreements to repurchase on a forward starting basis that are primarily secured by U.S. government and agency securities.
	Other Unfunded Commitments. Other unfunded commitments include obligations in the form of revolving notes to provide financing to asset-backed and CLO vehicles. Upon advancing funds, drawn amounts are collateralized by the assets of an entity.
	Contingencies
	Jefferies Group Inc. Acquisition -- Seven class-action lawsuits had been filed in New York and Delaware on behalf of a class consisting of Jefferies Group's stockholders concerning the transaction through which Jefferies Group Inc. became our wholly-owned subsidiary. The class actions named as defendants the Company, Jefferies Group, certain members of our board of directors, certain members of Jefferies Group's board of directors and, in certain of the actions, certain transaction-related subsidiaries. On October 31, 2014, the remaining defendants in the Delaware litigation entered into a settlement agreement with the plaintiffs in the Delaware litigation. The terms of that agreement provide for an aggregate payment of $70.0 million to certain former equity holders of Jefferies Group Inc., other than the defendants and certain of their affiliates, along with attorneys' fees to be determined and approved by the court; we have accrued for this aggregate payment and attorneys' fees. The settlement resolves all of the class-action claims in Delaware, and releases the claims brought in New York. The Delaware court approved the settlement on March 25, 2015, but has not yet determined the amount of attorneys' fees to be awarded. Plaintiffs have sought $27.5 million in fees and $1.1 million in expenses. While the defendants continue to deny each of the plaintiffs' claims and deny any liability, the defendants have entered into the settlement solely to settle and resolve their disputes, to avoid the costs and risks of further litigation and to avoid further distractions to our management.
	Sykes v. Mel Harris & Associates, LLC. -- We and certain of our subsidiaries and officers are named as defendants in a consumer class action captioned Sykes v. Mel Harris & Associates, LLC, et al., 09 Civ. 8486 (DC), in the United States District Court for the Southern District of New York. The named defendants also include the Mel Harris law firm, certain individuals and members associated with the law firm, and a process server, Samserv, Inc. and certain of its employees. The complaint alleges that default judgments obtained by the law firm against approximately 124,000 individuals in New York courts with respect to consumer debt purchased by our subsidiaries violated the Fair Debt Collection Practices Act, the Racketeer Influenced and Corrupt Organizations Act, the New York General Business Law and the New York Judiciary Law (alleged only as to the law firm). The complaint seeks injunctive relief, declaratory relief and damages on behalf of the named plaintiffs and others similarly situated. We asserted that we were an investor with respect to the subject purchased consumer debt and were regularly informed of the amounts received from debt collections, but otherwise had no involvement in any alleged illegal debt collection activities.
	On December 29, 2010, the District Court denied defendants' motions to dismiss in part (including as to the claims made against us and our subsidiaries) and granted them in part (including as to certain of the claims made against our officers). On March 28, 2013, the Court certified a Rule 23(b)(2) class and a Rule 23(b)(3) class. On February 10, 2015, the Second Circuit affirmed the certification of these classes. None of these decisions addresses the ultimate merits of the case.
	On March 18, 2015, we and plaintiffs executed a settlement agreement that provided additional detail regarding the terms of a settlement set out in a December 14, 2014 binding term sheet pursuant to which we expensed $3.2 million in the fourth quarter. This amount is in addition to the $20.0 million previously accrued for this matter and the $22.8 million in deferred revenue. The settlement agreement will be submitted to the District Court for its approval upon completion of the drafting of related documents.
	Haverhill Retirement System v. Asali, et al. -- On May 2, 2014, plaintiff Haverhill Retirement System ("Haverhill") filed an amended putative class action and derivative lawsuit (the "Complaint") entitled Haverhill Retirement System v. Asali, et al. in the Court of Chancery of the State of Delaware (the "Court of Chancery") against Harbinger Capital Partners LLC, Harbinger Capital Partners Master Fund I, Ltd., Global Opportunities Breakaway Ltd., Harbinger Capital Partners Special Situations Fund, L.P. (collectively, the "Harbinger Funds"), the members of the board of directors of Harbinger Group, Inc. ("Harbinger"), nominal defendant Harbinger, as well as Leucadia. The Complaint alleges, among other things, that the directors of Harbinger breached their fiduciary duties in connection with Leucadia's March 2014 purchase of preferred securities of subsidiaries of the Harbinger Funds that were exchangeable into Harbinger common stock owned by the Harbinger Funds, certain flaws in the process employed by the special committee of directors appointed by the Harbinger board in connection therewith, and that Leucadia aided and abetted the Harbinger board's breaches of fiduciary, as well as a claim of unjust enrichment against Leucadia. On April 1, 2014, the Chancery Court denied Haverhill's motion for expedited proceedings associated with the complaint originally filed by Haverhill on March 26, 2014. Haverhill filed an amended complaint on May 2, 2014. On July 2, 2014, the defendants moved to dismiss the amended complaint. On August 12, 2014, Plaintiffs filed another amended complaint. The amended complaint dropped Plaintiff's unjust enrichment claim against Leucadia. With respect to remedies sought, the amended complaint no longer sought an injunction against installing Leucadia designees as Board members and no longer sought rescission of Leucadia's right to select the director class to which one of its designees would be appointed. A settlement has been agreed by the parties that does not provide for any payment by the Company and includes, among other things, additional disclosures by Harbinger. A term sheet reflecting the settlement was signed on October 15, 2014. On December 19, 2014, final settlement papers were submitted to the Court. A settlement hearing was scheduled for April 6, 2015 and is now scheduled for June 8, 2015.
	Other Contingencies -- During the first quarter of 2014, Jefferies reached a non-prosecution agreement with the United States Attorney for the District of Connecticut and a settlement agreement with the SEC relating to an investigation of purchases and sales of mortgage-backed securities. That investigation arose from a matter that came to light in late 2011, at which time Jefferies terminated a mortgage-backed securities trader who was then indicted by the United States Attorney for the District of Connecticut in January 2013 and separately charged in a civil complaint by the SEC. Those agreements included an aggregate $25.0 million in payments, of which approximately $11.0 million constituted payments to trading counterparties impacted by those activities, approximately $10.0 million of which was a fine payable to the U.S. Attorney's Office, and approximately $4.0 million of which is a fine payable to the SEC. At March 31, 2015, Jefferies outstanding reserve with respect to remaining payments to be made under the agreements was approximately $1.0 million. Additionally, in April 2014, pursuant to an undertaking required by the SEC settlement, Jefferies retained an Independent Compliance Consultant ("ICC"). The ICC's review concluded in January 2015 upon the submission of its final report to the SEC and our adoption of the recommendations contained therein.
	We and our subsidiaries are parties to other legal and regulatory proceedings that are considered to be either ordinary, routine litigation incidental to their business or not significant to our consolidated financial position. We and our subsidiaries are also involved, from time to time, in other exams, investigations and similar reviews (both formal and informal) by governmental and self-regulatory agencies regarding our businesses, certain of which may result in judgments, settlements, fines, penalties or other injunctions. We do not believe that any of these actions will have a significant adverse effect on our consolidated financial position or liquidity, but any amounts paid could be significant to results of operations for the period.
	Guarantees
	Derivative Contracts. Jefferies dealer activities cause it to make markets and trade in a variety of derivative instruments. Certain derivative contracts that Jefferies has entered into meet the accounting definition of a guarantee under GAAP, including credit default swaps, written foreign currency options and written equity put options. On certain of these contracts, such as written interest rate caps and foreign currency options, the maximum payout cannot be quantified since the increase in interest or foreign exchange rates are not contractually limited by the terms of the contract. As such, we have disclosed notional values as a measure of Jefferies maximum potential payout under these contracts.
	The following table summarizes the notional amounts associated with our derivative contracts meeting the definition of a guarantee under GAAP (in millions):
					Expected Maturity Date
							2017		2019		2021		Notional/
							and		and		and		Maximum
	Guarantee Type		2015		2016		2018		2020		Later		Payout
	Derivative contracts – non-credit related	$	37,182.40	$	2,241.60	$	561.4	$	699.1	$	438.9	$	41,123.40
	Written derivative contracts – credit
	related		2		–		–		2,762.20		84		2,848.20
	Total derivative contracts	$	37,184.40	$	2,241.60	$	561.4	$	3,461.30	$	522.9	$	43,971.60
	The external credit ratings of the underlying or referenced assets for our credit related derivatives contracts (in millions):
		External Credit Rating
											Below				Notional/
			AAA/		AA/						Investment				Maximum
			Aaa		Aa		A		BBB/Baa		Grade		Unrated		Payout
	Credit related derivative contracts:
	Index credit default swaps	$	2,772.20	$	–	$	–	$	–	$	–	$	–	$	2,772.20
	Single name credit default swaps	$	–	$	–	$	–	$	12	$	64	$	–		76
	The derivative contracts deemed to meet the definition of a guarantee under GAAP are before consideration of hedging transactions and only reflect a partial or "one-sided" component of any risk exposure. Written equity options and written credit default swaps are often executed in a strategy that is in tandem with long cash instruments (e.g., equity and debt securities). Jefferies substantially mitigates its exposure to market risk on these contracts through hedges, such as other derivative contracts and/or cash instruments and Jefferies manages the risk associated with these contracts in the context of its overall risk management framework. Jefferies believes notional amounts overstate its expected payout and that fair value of these contracts is a more relevant measure of its obligations. The fair value of derivative contracts meeting the definition of a guarantee is approximately $567.1 million.
	Berkadia. We have agreed to reimburse Berkshire Hathaway for up to one-half of any losses incurred under a $2.5 billion surety policy securing outstanding commercial paper issued by an affiliate of Berkadia. As of March 31, 2015, the aggregate amount of commercial paper outstanding was $2.47 billion.
Loan Guarantee. Jefferies has provided a guarantee to Jefferies Finance that matures in January 2021, whereby Jefferies is required to make certain payments to a SPE sponsored by Jefferies Finance in the event that Jefferies Finance is unable to meet its obligations to the SPE and a guarantee of a credit agreement with an indefinite term for a fund owned by employees. At March 31, 2015, the maximum amount payable under these guarantees is $31.0 million.
Other Guarantees. Jefferies is a member of various exchanges and clearing houses. In the normal course of business Jefferies provides guarantees to securities clearinghouses and exchanges. These guarantees generally are required under the standard membership agreements, such that members are required to guarantee the performance of other members. Additionally, if a member becomes unable to satisfy its obligations to the clearinghouse, other members would be required to meet these shortfalls. To mitigate these performance risks, the exchanges and clearinghouses often require members to post collateral. Jefferies obligations under such guarantees could exceed the collateral amounts posted. Jefferies maximum potential liability under these arrangements cannot be quantified; however, the potential for Jefferies to be required to make payments under such guarantees is deemed remote. Accordingly, no liability has been recognized for these arrangements.
Indemnification. In connection with the 2013 sale of Empire Insurance Company, we agreed to indemnify the buyer for certain of Empire's lease obligations that were assumed by another subsidiary of ours as part of the sale of Empire. Our subsidiary was subsequently sold in 2014 to HomeFed as part of the real estate transaction with HomeFed. Although HomeFed has agreed to indemnify us for these lease obligations, our indemnification obligation under the Empire transaction remains. The primary lease expires in 2018 and the aggregate amount of lease obligation as of March 31, 2015 was approximately $38.0 million. Substantially all of the space under the primary lease has been sublet to various third-party tenants for the full length of the lease term in amounts in excess of the obligations under the primary lease.
Standby Letters of Credit. At March 31, 2015, Jefferies provided guarantees to certain counterparties in the form of standby letters of credit in the amount of $45.9 million, which expire within one year. Standby letters of credit commit Jefferies to make payment to the beneficiary if the guaranteed party fails to fulfill its obligation under a contractual arrangement with that beneficiary. Since commitments associated with these collateral instruments may expire unused, the amount shown does not necessarily reflect the actual future cash funding requirement.
Other subsidiaries of ours have outstanding letters of credit aggregating $22.6 million at March 31, 2015.

Net_Capital_Requirements

Net Capital Requirements	3 Months Ended
	Mar. 31, 2015
Net Capital Requirements [Abstract]
Net Capital Requirements	Note 22. Net Capital Requirements
	As broker-dealers registered with the SEC and member firms of the Financial Industry Regulatory Authority ("FINRA"), Jefferies LLC and Jefferies Execution Services, Inc. ("Jefferies Execution"), are subject to the SEC Net Capital Rule ("Rule 15c3-1"), which requires the maintenance of minimum net capital and have elected to calculate minimum capital requirements under the alternative method as permitted by Rule 15c3-1 in calculating net capital. Jefferies is also registered as an FCM, and is also subject to Rule 1.17 of the CFTC, which sets forth minimum financial requirements. The minimum net capital requirement in determining excess net capital for a dually-registered U.S. broker-dealer and FCM is equal to the greater of the requirement under Rule 15c3-1 or CFTC Rule 1.17.
	Jefferies LLC and Jefferies Execution's net capital and excess net capital are as follows (in thousands):
					Excess
			Net Capital		Net Capital
	Jefferies LLC	$	954,261	$	837,399
	Jefferies Execution		7,132		6,882
	FINRA is the designated self-regulatory organization ("DSRO") for our U.S. broker-dealers and the Chicago Mercantile Exchange is the DSRO for Jefferies LLC as an FCM.
	Certain other U.S. and non-U.S. subsidiaries of Jefferies are subject to capital adequacy requirements as prescribed by the regulatory authorities in their respective jurisdictions, including Jefferies International Limited and Jefferies Bache Limited which are authorized and regulated by the Financial Conduct Authority in the United Kingdom.
	The regulatory capital requirements referred to above may restrict our ability to withdraw capital from our regulated subsidiaries.

Other_Fair_Value_Information

Other Fair Value Information	3 Months Ended
	Mar. 31, 2015
Other Fair Value Information [Abstract]
Other Fair Value Information	Note 23. Other Fair Value Information
	The carrying amounts and estimated fair values of our principal financial instruments that are not recognized at fair value on a recurring basis are as follows (in thousands):
			31-Mar-15				31-Dec-14
			Carrying		Fair		Carrying		Fair
			Amount		Value		Amount		Value
	Other Assets:
	Notes and loans receivable (a)	$	249,385	$	262,956	$	213,174	$	217,171
	Financial Liabilities:
	Short-term borrowings (b)		411,998		411,998		12,000		12,000
	Long-term debt (b)		8,558,783		8,662,603		8,527,929		8,806,700
	(a) Notes and loans receivable: The fair values are primarily measured using Level 2 and 3 inputs principally based on discounted future cash flows using market interest rates for similar instruments.
	(b) Short-term borrowings and long-term debt: The fair values of short-term borrowings are estimated to be the carrying amount. The fair values of non-variable rate debt are estimated using quoted prices and estimated rates that would be available for debt with similar terms. The fair value of variable rate debt is estimated to be the carrying amount.

Related_Party_Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2015
Related Party Transactions [Abstract]
Related Party Transactions	Note 24. Related Party Transactions
	Jefferies Capital Partners and JEP IV Related Funds. Jefferies has loans to and/or equity investments in private equity funds and in Jefferies Capital Partners, LLC, the manager of the Jefferies Capital Partners funds, which are managed by a team led by Brian P. Friedman, our President and a Director ("Private Equity Related Funds"). Reflected in our Consolidated Statements of Financial Condition at March 31, 2015 and December 31, 2014 are loans to and/or equity investments in Private Equity Related Funds of $35.9 million and $60.7 million, respectively. Net losses aggregating $25.2 million and $2.5 million were recorded related to the Private Equity Related Funds for the three months ended March 31, 2015 and 2014, respectively. For further information regarding our commitments and funded amounts to Private Equity Related Funds, see Note 21.
	Berkadia Commercial Mortgage, LLC. At March 31, 2015 and December 31, 2014, Jefferies has commitments to purchase $356.4 million and $344.8 million, respectively, in agency commercial mortgage-backed securities from Berkadia.
	HRG Group, Inc. As part of Jefferies loan secondary trading activities, it has unsettled purchases and sales of loans pertaining to portfolio companies within funds managed by HRG of $248.1 million and $232.0 million at March 31, 2015 and December 31, 2014, respectively. Our Chairman also serves as HRG's Chairman.
	Officers, Directors and Employees. We have $23.3 million and $20.1 million of loans outstanding to certain employees (none of whom are an executive officer or director of the Company) that are included in Other assets in the Consolidated Statements of Financial Condition at March 31, 2015 and December 31, 2014, respectively. Receivables from and payables to customers include balances arising from officers, directors and employees individual security transactions. These transactions are subject to the same regulations as all customer transactions and are provided on substantially the same terms. At March 31, 2015 and December 31, 2014, Jefferies provided a guarantee of a credit agreement for a private equity fund owned by Jefferies employees.
	National Beef. National Beef participates in a cattle supply agreement with a minority owner and holder of a redeemable noncontrolling interest in National Beef. Under this agreement National Beef has agreed to purchase 735,385 head of cattle each year (subject to adjustment), from the members of the minority owner, with prices based on those published by the U.S. Department of Agriculture, subject to adjustments for cattle performance. National Beef obtained approximately 22% and 20% of its cattle requirements under this agreement during the three months ended March 31, 2015 and 2014, respectively.
	National Beef also enters into transactions with an affiliate of another minority owner and holder of a redeemable noncontrolling interest in National Beef to buy and sell a limited number of beef products. During the three months ended March 31, 2015, sales to this affiliate were $9.4 million and purchases were $3.6 million. During the three months ended March 31, 2014, sales to this affiliate were $7.4 million and purchases were $2.4 million. At March 31, 2015 and December 31, 2014, amounts due from and payable to these related parties were not significant. Both of these arrangements are based on what we believe to be competitive market prices.
	HomeFed. As more fully described in Note 9, during 2014 we sold to HomeFed substantially all of our real estate properties and operations, our interest in BRP and cash of approximately $14.0 million, in exchange for 7,500,000 newly issued unregistered HomeFed common shares. As discussed in Note 9, as a result of a 1998 distribution to all of our shareholders, approximately 4.8% of HomeFed is beneficially owned by our Chairman at March 31, 2015. Our Chairman also serves as HomeFed's Chairman and our President is a Director of HomeFed.
	See Note 9 for information on transactions with Jefferies Finance and Jefferies LoanCore.

Discontinued_Operations

Discontinued Operations	3 Months Ended
	Mar. 31, 2015
Discontinued Operations [Abstract]
Discontinued Operations	Note 25. Discontinued Operations
	Discontinued operations for the three month 2014 period primarily consists of the Lake Charles clean energy project and Premier.
	A summary of the results of discontinued operations is as follows for the three months ended March 31, 2014 (in thousands):
	Revenues and other income:
	Gaming entertainment	$	31,004
	Investment and other income		810
			31,814
	Expenses:
	Direct operating expenses – Gaming
	entertainment		23,429
	Compensation and benefits		1,172
	Depreciation and amortization		2,224
	Selling, general and other expenses		18,694
			45,519
	Loss from discontinued
	operations before income taxes		(13,705	)
	Income tax (benefit)		(4,796	)
	Loss from discontinued operations after income taxes	$	(8,909	)

Segment_Information

Segment Information	3 Months Ended
	Mar. 31, 2015
Segment Information [Abstract]
Segment Information	Note 26. Segment Information
	Our operating segments consist of our consolidated businesses, which offer different products and services and are managed separately. Our reportable segments, based on qualitative and quantitative requirements, are Jefferies, National Beef, and Corporate and other. Jefferies is a global full-service, integrated securities and investment banking firm. National Beef processes and markets fresh boxed beef, case-ready beef, beef by-products and wet blue leather for domestic and international markets. All other consists of our other financial services businesses and our other merchant banking businesses. Our other financial services businesses include the Leucadia asset management platform, specialty finance companies, the commercial mortgage banking investment, the investment in HomeFed and the investment in FXCM. Our other merchant banking businesses primarily include manufacturing, oil and gas exploration and development, real estate, and our investments in fixed wireless broadband services, automobile dealerships, and our gold and silver mining project.
	Corporate and other assets primarily consist of financial instruments owned, the deferred tax asset (exclusive of Jefferies deferred tax asset), cash and cash equivalents and corporate and other revenues primarily consist of interest, other income and net realized securities gains and losses. We do not allocate Corporate and other revenues or overhead expenses to the operating units.
	Certain information concerning our segments for the three months ended March 31, 2015 and 2014 is presented in the following table. Consolidated subsidiaries are reflected as of the date a majority controlling interest was acquired. As discussed above, Jefferies is reflected in our consolidated financial statements utilizing a one month lag.
			2015			2014
			(In thousands)
	Net Revenues:
	Reportable Segments:
	Jefferies	$	591,441		$	930,512
	National Beef		1,856,019			1,887,378
	Corporate and other		20,316			13,684
	Total net revenues related to reportable
	segments		2,467,776			2,831,574
	All other		737,907			110,950
	Intercompany eliminations		(21,000	)		–
	Total consolidated net revenues	$	3,184,683		$	2,942,524
	Pre-tax income (loss) from continuing
	operations:
	Reportable Segments:
	Jefferies	$	12,924		$	196,370
	National Beef		(33,585	)		(28,013	)
	Corporate and other		(9,864	)		(19,231	)
	Pre-tax income (loss) from continuing
	operations related to reportable segments		(30,525	)		149,126
	All other		641,932			33,147
	Parent Company interest		(24,300	)		(25,177	)
	Total consolidated pre-tax income from
	continuing operations	$	587,107		$	157,096
	Depreciation and amortization expenses:
	Reportable Segments:
	Jefferies	$	22,250		$	17,031
	National Beef		21,787			20,760
	Corporate and other		970			1,337
	Total depreciation and amortization
	expenses related to reportable segments		45,007			39,128
	All other		7,433			2,359
	Total consolidated depreciation and
	amortization expenses	$	52,440		$	41,487
	All other revenue and pre-tax income from continuing operations in the above table include $686.6 million of unrealized and realized gains relating to our investment in FXCM for the three months ended March 31, 2015.
	Interest expense classified as a component of Net revenues relates to Jefferies. For the three months ended March 31, 2015 and 2014, interest expense classified as a component of Expenses was primarily comprised of National Beef ($4.2 million and $3.1 million, respectively) and parent company interest ($24.3 million and $25.2 million, respectively).

Subsequent_Events

Subsequent Events	3 Months Ended
	Mar. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	Note 27. Subsequent Events
	Jefferies Bache. On April 9, 2015, Jefferies Group LLC, our wholly-owned subsidiary, entered into an agreement with Société Générale S.A. to transfer certain client exchange and over-the-counter transactions associated with Jefferies futures business for the net book value of the over-the-counter transactions, calculated in accordance with certain principles set forth in the agreement, plus the repayment of certain margin loans in respect of certain exchange transactions. In addition, Jefferies agreed to enter into a total return swap with respect to other over-the-counter transactions which will not be transferred, which is intended to replicate the economics of such non-transferred over-the-counter transactions. The transfer is subject to customary closing conditions for a transaction of this nature. Jefferies anticipates that the completion of this transaction will occur during its second quarter of 2015. Jefferies is not able to estimate, at this time, the total assets and liabilities that will be transferred as such amounts will fluctuate based on daily client activity through the date of closing.
	In addition, Jefferies expects to terminate its $750.0 million credit facility shortly after the closing of the above transaction. Upon termination of the credit facility, unamortized deferred origination costs of $5.4 million will be expensed.
	Concurrently, Jefferies initiated a plan to exit the remaining aspects of its existing futures business and to terminate the remaining client agreements with respect to exchange transactions. Jefferies estimates that it will incur the pre-tax costs set forth below that aggregate approximately $91.2 million in connection with this plan, primarily over the remainder of its 2015 fiscal year. Jefferies expects the effect of these costs to be approximately $65.8 million on an after-tax basis. Of the total estimated costs, approximately $23.0 million are of a non-cash nature and approximately $68.2 million will result in future cash expenditures.
		(In millions)
	Compensation and benefits (including severance costs,
	retention awards and amortization expense for existing
	restricted stock and restricted cash compensation awards)	$	39.8
	Accelerated capitalized software amortization		20.8
	Technology and communications service agreements		24.5
	Impairment of exchange memberships		2.5
	Other expenses		3.6
	Total	$	91.2
	All of the above costs will be incurred by us in our consolidated financial statements. All of the above costs associated with the plan to exit the futures business, the nature of such costs and the effect of such costs are estimates only and are subject to change.
	FXCM Holdings, LLC. On April 1, 2015, Jefferies entered into an agreement (the "Agreement") with FXCM Holdings, LLC and FXCM's subsidiary, Faros Trading, LLC ("Faros") to acquire their agency foreign exchange business and, in connection therewith, to hire certain employees of Faros. The Agreement, the consideration for which is contingent on net profits, if any, from the operation of the business through November 30, 2017, is expected to close during the second quarter of 2015. We do not believe this transaction will have a material impact on our financial position or results of operations.

Basis_Of_Presentation_And_Sign1

Basis Of Presentation And Significant Accounting Policies (Policy)	3 Months Ended
	Mar. 31, 2015
Basis Of Presentation And Significant Accounting Policies [Abstract]
Fair Value Hierarchy	Fair Value Hierarchy
	In determining fair value, we maximize the use of observable inputs and minimize the use of unobservable inputs by requiring that observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from independent sources. Unobservable inputs reflect our assumptions that market participants would use in pricing the asset or liability developed based on the best information available in the circumstances. We apply a hierarchy to categorize our fair value measurements broken down into three levels based on the transparency of inputs as follows:
	Level 1:	Quoted prices are available in active markets for identical assets or liabilities as of the reported date.
	Level 2:	Pricing inputs are other than quoted prices in active markets, which are either directly or indirectly observable as of the reported date. The nature of these financial instruments include cash instruments for which quoted prices are available but traded less frequently, derivative instruments whose fair value have been derived using a model where inputs to the model are directly observable in the market, or can be derived principally from or corroborated by observable market data, and instruments that are fair valued using other financial instruments, the parameters of which can be directly observed.
	Level 3:	Instruments that have little to no pricing observability as of the reported date.	These financial instruments are
		measured using management's best estimate of fair value, where the inputs into the determination of fair value
		require significant management judgment or estimation.
	Financial instruments are valued at quoted market prices, if available. Certain financial instruments have bid and ask prices that can be observed in the marketplace. For financial instruments whose inputs are based on bid-ask prices, the financial instrument is valued at the point within the bid-ask range that meets our best estimate of fair value. We use prices and inputs that are current as of the measurement date. For financial instruments that do not have readily determinable fair values using quoted market prices, the determination of fair value is based upon consideration of available information, including types of financial instruments, current financial information, restrictions on dispositions, fair values of underlying financial instruments and quotations for similar instruments.
	The valuation of financial instruments may include the use of valuation models and other techniques. Adjustments to valuations derived from valuation models may be made when, in management's judgment, features of the financial instrument such as its complexity, the market in which the financial instrument is traded and risk uncertainties about market conditions require that an adjustment be made to the value derived from the models. Adjustments from the price derived from a valuation model reflect management's judgment that other participants in the market for the financial instrument being measured at fair value would also consider in valuing that same financial instrument. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment.
	The availability of observable inputs can vary and is affected by a wide variety of factors, including, for example, the type of financial instrument and market conditions. As the observability of prices and inputs may change for a financial instrument from period to period, this condition may cause a transfer of an instrument among the fair value hierarchy levels. Transfers among the levels are recognized at the beginning of each period. The degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3.
Jefferies Valuation Process For Financial Instruments	Jefferies Valuation Process for Financial Instruments
	The Jefferies Independent Price Verification ("IPV") Group, which is part of the Jefferies finance department, in partnership with Jefferies Risk Management, is responsible for establishing Jefferies valuation policies and procedures. The IPV Group and Risk Management, which are independent of business functions, play an important role and serve as a control function in determining that Jefferies financial instruments are appropriately valued and that fair value measurements are reliable. This is particularly important where prices or valuations that require inputs are less observable. In the event that observable inputs are not available, the control processes are designed to assure that the valuation approach utilized is appropriate and consistently applied and that the assumptions are reasonable. The IPV Group reports to the Jefferies Global Controller and is subject to the oversight of the IPV Committee, which includes senior members of Jefferies finance department and other personnel. Jefferies independent price verification policies and procedures are reviewed, at a minimum, annually and changes to the policies require the approval of the IPV Committee.
	Price Testing Process. Jefferies business units are responsible for determining the fair value of Jefferies financial instruments using approved valuation models and methodologies. In order to ensure that the business unit valuations represent a fair value exit price, the IPV Group tests and validates the fair value of the financial instruments inventory. In the testing process, the IPV Group obtains prices and valuation inputs from sources independent of Jefferies, consistently adheres to established procedures set forth in the valuation policies for sourcing prices and valuation inputs and utilizing valuation methodologies. Sources used to validate fair value prices and inputs include, but are not limited to, exchange data, recently executed transactions, pricing data obtained from third party vendors, pricing and valuation services, broker quotes and observed comparable transactions.
	To the extent discrepancies between the business unit valuations and the pricing or valuations resulting from the price testing process are identified, such discrepancies are investigated by the IPV Group and fair values are adjusted, as appropriate. The IPV Group maintains documentation of its testing, results, rationale and recommendations and prepares a monthly summary of its valuation results. This process also forms the basis for the classification of fair values within the fair value hierarchy (i.e., Level 1, Level 2 or Level 3). The IPV Group utilizes the additional expertise of Risk Management personnel in valuing more complex financial instruments and financial instruments with less or limited pricing observability. The results of the valuation testing are reported to the IPV Committee on a monthly basis, which discusses the results and is charged with the final conclusions as to the financial instrument fair values in the consolidated financial statements. This process specifically assists management in asserting as to the fair presentation of our financial condition and results of operations as included within our Quarterly Reports on Form 10-Q and Annual Report on Form 10-K. At each quarter end, the overall valuation results, as concluded upon by the IPV Committee, are presented to the Jefferies Audit Committee.
	Judgment exercised in determining Level 3 fair value measurements is supplemented by daily analysis of profit and loss performed by the Product Control functions. Gains and losses, which result from changes in fair value, are evaluated and corroborated daily based on an understanding of each of the trading desks' overall risk positions and developments in a particular market on the given day. Valuation techniques generally rely on recent transactions of suitably comparable financial instruments and use the observable inputs from those comparable transactions as a validation basis for Level 3 inputs. Level 3 fair value measurements are further validated through subsequent sales testing and market comparable sales, if such information is available. Level 3 fair value measurements require documentation of the valuation rationale applied, which is reviewed for consistency in application from period to period; and the documentation includes benchmarking the assumptions underlying the valuation rationale against relevant analytic data.
	Third Party Pricing Information. Pricing information obtained from external data providers (including independent pricing services and brokers) may incorporate a range of market quotes from dealers, recent market transactions and benchmarking model derived prices to quoted market prices and trade data for comparable securities. External pricing data is subject to evaluation for reasonableness by the IPV Group using a variety of means including comparisons of prices to those of similar product types, quality and maturities, consideration of the narrowness or wideness of the range of prices obtained, knowledge of recent market transactions and an assessment of the similarity in prices to comparable dealer offerings in a recent time period. Jefferies has a process whereby it challenges the appropriateness of pricing information obtained from external data providers (including independent pricing services and brokers) in order to validate the data for consistency with the definition of a fair value exit price. Jefferies process includes understanding and evaluating the external data providers' valuation methodologies. For corporate, U.S. government and agency, municipal debt securities, and loans, to the extent independent pricing services or broker quotes are utilized in our valuation process, the vendor service providers are collecting and aggregating observable market information as to recent trade activity and active bid-ask submissions. The composite pricing information received from the independent pricing service is not based on unobservable inputs or proprietary models. For mortgage- and other asset-backed securities and collateralized debt obligations, the independent pricing services use a matrix evaluation approach incorporating both observable yield curves and market yields on comparable securities as well as implied inputs from observed trades for comparable securities in order to determine prepayment speeds, cumulative default rates and loss severity. Further, Jefferies considers pricing data from multiple service providers as available as well as compares pricing data to prices observed for recent transactions, if any, in order to corroborate valuation inputs.
	Model Review Process. Where a pricing model is to be used to determine fair value, the pricing model is reviewed for theoretical soundness and appropriateness by Risk Management, independent from the trading desks, and then approved by Risk Management to be used in the valuation process. Review and approval of a model for use may include benchmarking the model against relevant third party valuations, testing sample trades in the model, backtesting the results of the model against actual trades and stress-testing the sensitivity of the pricing model using varying inputs and assumptions. In addition, recently executed comparable transactions and other observable market data are considered for purposes of validating assumptions underlying the model. Models are independently reviewed and validated by Risk Management annually or more frequently if market conditions or use of the valuation model changes.
Receivables And Provision For Doubtful Accounts	Receivables
	At March 31, 2015 and December 31, 2014, Receivables include receivables from brokers, dealers and clearing organizations of $2,222.3 million and $2,187.5 million, respectively, and receivables from customers of securities operations of $1,343.6 million and $1,250.5 million, respectively.
Payables, Expense Accruals And Other Liabilities	Payables, expense accruals and other liabilities
	At March 31, 2015 and December 31, 2014, Payables, expense accruals and other liabilities include payables to brokers, dealers and clearing organizations of $2,663.0 million and $2,280.1 million, respectively, and payables to customers of securities operations of $4,757.5 million and $6,242.0 million, respectively.
Accounting Developments	Accounting Developments
	Discontinued Operations. In January 2015, we adopted new Financial Accounting Standards Board ("FASB") guidance on the reporting of discontinued operations. The new guidance requires that disposal of a component of an entity or a group of components of an entity be reported as discontinued operations if the disposal represents a strategic shift that has (or will have) a major effect on an entity's operations and financial results, and would require expanded disclosures. The adoption of this guidance did not have an impact on our consolidated financial statements.
	Revenue Recognition. In May 2014, the FASB issued new guidance that defines how companies report revenues from contracts with customers, and also requires enhanced disclosures. The core principle of this new guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. This guidance will be effective for interim and annual periods beginning after December 15, 2016. In April 2015, the FASB announced a proposal to defer the effective date by one year, with early adoption on the original effective date permitted. We are currently evaluating the impact this new guidance will have on our consolidated financial statements to the extent applicable.
	Repurchase Agreements. In January 2015, we adopted the FASB's new guidance that changes the accounting for repurchase-to-maturity transactions and linked repurchase financings to secured borrowing accounting, which is consistent with the accounting for other repurchase agreements. This guidance did not significantly affect our consolidated results of operations, financial condition or cash flows. Effective for interim periods beginning after March 31, 2015, the guidance also requires new disclosures about transfers that are accounted for as sales in transactions that are economically similar to repurchase agreements and increased transparency about the types of collateral pledged in repurchase agreements and similar transactions accounted for as secured borrowings. We will provide the additional disclosures in our consolidated financial statements.
	Consolidation. In February 2015, the FASB issued new guidance that amends current consolidation guidance including changes to both the variable and voting interest models used to evaluate whether an entity should be consolidated. This guidance also eliminates the deferral of certain consolidation standards for entities considered to be investment companies. This guidance will be effective for annual and interim periods beginning after December 15, 2015, and early adoption is permitted. We are evaluating the impact this new guidance will have on our consolidated financial statements.
	Debt Issuance Costs. In April 2015, the FASB issued new guidance that requires debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability. This guidance will be effective for annual and interim periods beginning after December 15, 2015, and early adoption is permitted. The adoption of this guidance is not expected to have a significant impact on our consolidated statement of financial condition.

Fair_Value_Disclosures_Tables

Fair Value Disclosures (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Schedule Of Assets And Liabilities Measured On Recurring Basis At Fair Value
		31-Mar-15
									Counterparty
									and
									Cash
									Collateral
			Level 1 (1)		Level 2 (1)		Level 3		Netting (2)			Total
	Assets:
	Trading assets, at fair value:
	Corporate equity securities	$	3,052,340	$	209,338	$	18,210	$	–		$	3,279,888
	Corporate debt securities		–		3,399,249		30,735		–			3,429,984
	Collateralized debt obligations		–		153,900		90,897		–			244,797
	U.S. government and federal agency securities		3,783,645		106,427		–		–			3,890,072
	Municipal securities		–		772,940		–		–			772,940
	Sovereign obligations		1,522,227		1,057,623		333		–			2,580,183
	Residential mortgage-backed securities		–		2,824,500		79,953		–			2,904,453
	Commercial mortgage-backed securities		–		542,089		24,629		–			566,718
	Other asset-backed securities		–		138,391		7,146		–			145,537
	Loans and other receivables		–		1,349,201		111,410		–			1,460,611
	Derivatives		96,660		5,083,829		46,136		(4,729,533	)		497,092
	Investments at fair value		–		3		193,094		–			193,097
	Investment in FXCM		–		–		947,000		–			947,000
	Physical commodities		–		58,715		–		–			58,715
	Total trading assets	$	8,454,872	$	15,696,205	$	1,549,543	$	(4,729,533	)	$	20,971,087
	Available for sale securities:
	Corporate equity securities	$	73,993	$	–	$	–	$	–		$	73,993
	Corporate debt securities		–		29,528		–		–			29,528
	U.S. government securities		213,611		–		–		–			213,611
	Residential mortgage-backed securities		–		498,876		–		–			498,876
	Commercial mortgage-backed securities		–		27,914		–		–			27,914
	Other asset-backed securities		–		130,508		–		–			130,508
	Total available for sale securities	$	287,604	$	686,826	$	–	$	–		$	974,430
	Cash and cash equivalents	$	3,524,524	$	–	$	–	$	–		$	3,524,524
	Investments in managed funds	$	–	$	160,456	$	433,125	$	–		$	593,581
	Cash and securities segregated and on deposit for regulatory
	purposes or deposited with clearing and depository
	organizations (3)	$	3,186,319	$	–	$	–	$	–		$	3,186,319
	Securities received as collateral	$	4,821	$	–	$	–	$	–		$	4,821
	Liabilities:
	Trading liabilities:
	Corporate equity securities	$	2,031,013	$	60,034	$	38	$	–		$	2,091,085
	Corporate debt securities		–		1,766,453		–		–			1,766,453
	U.S. government and federal agency securities		1,366,689		99,422		–		–			1,466,111
	Sovereign obligations		707,844		659,846		–		–			1,367,690
	Residential mortgage-backed securities		–		11,925		–		–			11,925
	Loans		–		910,569		9,327		–			919,896
	Derivatives		71,707		5,011,935		49,450		(4,810,751	)		322,341
	Total trading liabilities	$	4,177,253	$	8,520,184	$	58,815	$	(4,810,751	)	$	7,945,501
	Other secured financings	$	–	$	–	$	65,602	$	–		$	65,602
	Obligation to return securities received as collateral	$	4,821	$	–	$	–	$	–		$	4,821
		31-Dec-14
									Counterparty
									and
									Cash
									Collateral
			Level 1 (1)		Level 2 (1)		Level 3		Netting (2)			Total
	Assets:
	Trading assets, at fair value:
	Corporate equity securities	$	3,130,892	$	226,441	$	20,964	$	–		$	3,378,297
	Corporate debt securities		–		3,342,276		55,918		–			3,398,194
	Collateralized debt obligations		–		306,218		91,498		–			397,716
	U.S. government and federal agency securities		2,694,268		81,273		–		–			2,775,541
	Municipal securities		–		590,849		–		–			590,849
	Sovereign obligations		1,968,747		790,764		–		–			2,759,511
Residential mortgage-backed securities		–		2,879,954		82,557		–			2,962,511
Commercial mortgage-backed securities		–		966,651		26,655		–			993,306
Other asset-backed securities		–		137,387		2,294		–			139,681
Loans and other receivables		–		1,458,760		97,258		–			1,556,018
Derivatives		65,145		5,046,278		54,190		(4,759,345	)		406,268
Investments at fair value		–		73,152		119,212		–			192,364
Physical commodities		–		62,234		–		–			62,234
Total trading assets	$	7,859,052	$	15,962,237	$	550,546	$	(4,759,345	)	$	19,612,490
Available for sale securities:
Corporate equity securities	$	89,353	$	–	$	–	$	–		$	89,353
Corporate debt securities		–		30,403		–		–			30,403
U.S. government securities		593,773		–		–		–			593,773
Residential mortgage-backed securities		–		606,683		–		–			606,683
Commercial mortgage-backed securities		–		43,401		–		–			43,401
Other asset-backed securities		–		245,156		–		–			245,156
Total available for sale securities	$	683,126	$	925,643	$	–	$	–		$	1,608,769
Cash and cash equivalents	$	4,276,775	$	–	$	–	$	–		$	4,276,775
Investments in managed funds	$	–	$	226,488	$	54,982	$	–		$	281,470
Cash and securities segregated and on deposit for regulatory
purposes or deposited with clearing and depository
organizations (3)	$	3,444,674	$	–	$	–	$	–		$	3,444,674
Securities received as collateral	$	5,418	$	–	$	–	$	–		$	5,418
Liabilities:
Trading liabilities:
Corporate equity securities	$	1,934,469	$	74,681	$	38	$	–		$	2,009,188
Corporate debt securities		–		1,611,994		223		–			1,612,217
Collateralized debt obligations		–		4,557		–		–			4,557
U.S. government and federal agency securities		2,253,055		–		–		–			2,253,055
Sovereign obligations		1,217,075		574,010		–		–			1,791,085
Loans		–		856,525		14,450		–			870,975
Derivatives		52,778		5,117,803		49,552		(4,856,618	)		363,515
Total trading liabilities	$	5,457,377	$	8,239,570	$	64,263	$	(4,856,618	)	$	8,904,592
Other secured financings	$	–	$	–	$	30,825	$	–		$	30,825
Obligation to return securities received as collateral	$	5,418	$	–	$	–	$	–		$	5,418
(1) There were no transfers between Level 1 and Level 2 during the three months ended March 31, 2015. During the year ended December 31, 2014, equity options presented within Trading assets and Trading liabilities of $6.1 million and $6.6 million, respectively, were transferred from Level 1 to Level 2 as adjustments were incorporated into the valuation approach for such contracts to estimate the point within the bid-ask range that meets the best estimate of fair value.
(2) Represents counterparty and cash collateral netting across the levels of the fair value hierarchy for positions with the same counterparty.
(3) Securities comprise U.S. government securities segregated for regulatory purposes with a fair value of $434.8 million and $453.7 million at March 31, 2015 and December 31, 2014, respectively, and Commodities Futures Trading Commission ("CFTC") approved money market funds with a fair value of $810.0 million and $545.0 million at March 31, 2015 and December 31, 2014, respectively.
Investments Measured At Fair Value Based On Net Asset Value
						Redemption
					Unfunded	Frequency
			Fair Value (1)		Commitments	(if currently eligible)
	31-Mar-15
	Equity Long/Short Hedge Funds (2)	$	480,302	$	–	-2
	High Yield Hedge Funds (3)		196		–	–
	Fund of Funds (4)		340		94	–
	Equity Funds (5)		40,403		25,670	–
	Convertible Bond Funds (6)		3,470		–	At Will
	Multi-strategy Fund (7)		108,150		–	–
	Total (8)	$	632,861	$	25,764
	31-Dec-14
	Equity Long/Short Hedge Funds (2)	$	146,134	$	–	Monthly/Quarterly
	High Yield Hedge Funds (3)		204		–	–
	Fund of Funds (4)		323		94	–
	Equity Funds (5)		65,216		26,023	–
	Convertible Bond Funds (6)		3,355		–	At Will
	Multi-strategy Fund (7)		105,954		–	–
	Total (8)	$	321,186	$	26,117
	(1) Where fair value is calculated based on net asset value, fair value has been derived from each of the funds' capital statements.
	(2) This category includes investments in hedge funds that invest, long and short, in equity securities in domestic and international markets in both the public and private sectors. At March 31, 2015, investments with a fair value of $78.0 million and at December 31, 2014 substantially all of the investments in this category are redeemable with 30 to 90 days prior written notice, and includes an investment in a private asset management fund managed by us with a fair value of $48.8 million and $117.2 million at March 31, 2015 and December 31, 2014, respectively. At March 31, 2015, this category also includes investments in two Folger Hill feeder funds that invest solely in a Folger Hill master fund that makes long/short equity investments, with broad industry and geographic diversification. Investment in these funds is subject to a lock-up until August 15, 2019, subject to certain release events and other withdrawal rights. Following this date, investments can be redeemed as of any calendar quarter-end with no less than 45 calendar days' notice, subject to certain limitations. At March 31, 2015, our investments in these two funds had an aggregate fair value of $402.3 million.
	(3) Includes investments in funds that invest in domestic and international public high yield debt, private high yield investments, senior bank loans, public leveraged equities, distressed debt, and private equity investments. There are no redemption provisions. The underlying assets of the funds are being liquidated and we are unable to estimate when the underlying assets will be fully liquidated.
	(4) Includes investments in fund of funds that invest in various private equity funds. At March 31, 2015 and December 31, 2014, approximately 96% and 95%, respectively, of the fair value of investments in this category is managed by us and has no redemption provisions, instead distributions are received through the liquidation of the underlying assets of the fund of funds, which are estimated to be liquidated in approximately two years. For the remaining investments, we have requested redemption; however, we are unable to estimate when these funds will be received.
	(5) At March 31, 2015 and December 31, 2014, investments representing approximately 99% and 99%, respectively, of the fair value of investments in this category include investments in equity funds that invest in the equity of various U.S. and foreign private companies in the energy, technology, internet service and telecommunication service industries. These investments cannot be redeemed; instead distributions are received through the liquidation of the underlying assets of the funds which are expected to liquidate in one to eight years. The remaining investments are in liquidation and we are unable to estimate when the underlying assets will be fully liquidated.
	(6) Investment in the Jefferies Umbrella Fund, an open-ended investment company managed by us that invests primarily in convertible bonds. The investment is redeemable with five days prior written notice.
	(7) Investment in private asset management fund managed by us that employs a variety of investment strategies and can invest in U.S. and non-U.S. equity and equity related securities, futures, exchange traded funds, fixed income securities, preferred securities, options, forward contracts and swaps. Withdrawals from the fund prior to the first year anniversary of the investment are subject to a 5% withdrawal fee and withdrawals during any calendar quarter are limited to 25% of the fund's net asset value. Both of these restrictions can be waived by us, in our sole discretion.
	(8) Investments at fair value in the Consolidated Statements of Financial Condition at March 31, 2015 and December 31, 2014, include $153.8 million and $152.6 million, respectively, of direct investments which do not have the characteristics of investment companies and therefore not included within this table.
Summary Of Trading Assets And Trading Liabilities
		31-Mar-15				31-Dec-14
		Trading Assets		Trading Liabilities		Trading Assets		Trading Liabilities
	Exchange closing prices	14	%	25	%	16	%	20	%
	Recently observed transaction prices	4	%	3	%	4	%	2	%
	External pricing services	66	%	64	%	67	%	69	%
	Broker quotes	4	%	4	%	4	%	3	%
	Valuation techniques	12	%	4	%	9	%	6	%
		100	%	100	%	100	%	100	%
Summary Of Changes In Fair Value Of Financial Assets And Liabilities Classified As Level 3	Three Months Ended March 31, 2015
																									Changes in
																									unrealized
																									gains (losses)
																									relating to
						Total gains																			instruments
			Balance,			(losses)														Net transfers			Balance,		still held at
			December 31,			(realized and														into (out of)			March 31,		March 31,
			2014			unrealized) (1)			Purchases			Sales			Settlements			Issuances		Level 3			2015		2015 (1)
	Assets:
	Trading assets:
	Corporate equity securities	$	20,964		$	63		$	–		$	(168	)	$	–		$	–	$	(2,649	)	$	18,210	$	243
	Corporate debt securities		55,918			(1,930	)		469			(533	)		–			–		(23,189	)		30,735		(1,577	)
	Collateralized debt obligations		91,498			(16,022	)		–			(13,519	)		(1,296	)		–		30,236			90,897		(15,886	)
	Sovereign obligations		–			13			–			(1	)		–			–		321			333		12
	Residential mortgage-backed
	securities		82,557			(2,863	)		2,100			(1,375	)		(23	)		–		(443	)		79,953		783
	Commercial mortgage-backed
	securities		26,655			(531	)		–			(382	)		(6,864	)		–		5,751			24,629		(1,369	)
	Other asset-backed securities		2,294			(167	)		26			(1	)		–			–		4,994			7,146		(167	)
	Loans and other receivables		97,258			(5,033	)		40,019			(16,122	)		(15,448	)		–		10,736			111,410		(3,262	)
	Investments at fair value		119,212			609			5,010			(594	)		(277	)		–		69,134			193,094		614
	Investment in FXCM		–			686,627			279,000			–			(18,627	)		–		–			947,000		686,627
	Investments in managed funds		54,982			(22,211	)		400,354			–			–			–		–			433,125		(22,210	)
	Liabilities:
	Trading liabilities:
	Corporate equity securities	$	38		$	–		$	–		$	–		$	–		$	–	$	–		$	38	$	–
	Corporate debt securities		223			(115	)		(6,683	)		6,698			–			–		(123	)		–		–
	Net derivatives (2)		(4,638	)		6,938			–			–			(58	)		1,072		–			3,314		(8,771	)
	Loans		14,450			(39	)		(2,877	)		825			–			–		(3,032	)		9,327		39
	Other secured financings		30,825			–			–			–			(2,218	)		36,995		–			65,602		–
	(1) Realized and unrealized gains (losses) are reported in Principal transactions in the Consolidated Statements of Operations, except for realized and unrealized gains (losses) on Investments in managed funds, which are included in Other revenues in the Consolidated Statements of Operations.
	(2) Net derivatives represent Trading assets - Derivatives and Trading liabilities - Derivatives.
																							Changes in
																							unrealized
																							gains (losses)
																							relating to
					Total gains																		instruments
			Balance,		(losses)													Net transfers			Balance,		still held at
			December 31,		(realized and													into (out of)			March 31,		March 31,
			2013		unrealized) (1)			Purchases			Sales			Settlements		Issuances		Level 3			2014		2014 (1)
	Assets:
	Trading assets:
	Corporate equity securities	$	9,884	$	(1,393	)	$	134		$	–		$	–	$	–	$	3,716		$	12,341	$	(1,319	)
	Corporate debt securities		25,666		(2,014	)		4,136			(624	)		–		–		2,151			29,315		193
	Collateralized debt obligations		37,216		10,184			76,511			(78,081	)		(144	)	–		20,342			66,028		5,662
	Residential mortgage-backed															–
	securities		105,492		(1,626	)		9,637			(13,703	)		(1,755	)	–		18,947			116,992		(2,097	)
	Commercial mortgage-backed
	securities		17,568		(3,032	)		8,933			(14,645	)		(50	)	–		8,712			17,486		(958	)
	Other asset-backed securities		12,611		72			2,250			(2,048	)		(83	)	–		(10,427	)		2,375		7
	Loans and other receivables		145,890		(3,902	)		36,213			(49,475	)		(935	)	–		1,041			128,832		(3,807	)
	Investments at fair value		101,242		24,889			22,500			(9,012	)		–		–		(776	)		138,843		24,889
	Investments in managed funds		57,285		(2,859	)		5,102			–			–		–		–			59,528		(2,859	)
	Liabilities:
	Trading liabilities:
	Corporate equity securities	$	38	$	8		$	–		$	411		$	–	$	–	$	558		$	1,015	$	(8	)
	Net derivatives (2)		6,905		1,267			(1,327	)		2,169			197		–		(3,438	)		5,773		(1,267	)
	Loans		22,462		(153	)		(18,913	)		4,887			–		–		1,977			10,260		(153	)
	Other secured financings		8,711		–			–			–			–		21,683		–			30,394		–
	(1) Realized and unrealized gains (losses) are reported in Principal transactions in the Consolidated Statements of Operations, except for realized and unrealized gains (losses) on Investments in managed funds, which are included in Other revenues in the Consolidated Statements of Operations.
	(2) Net derivatives represent Trading assets - Derivatives and Trading liabilities - Derivatives.
Quantitative Information About Significant Unobservable Inputs Used In Level 3 Fair Value Measurements
	31-Mar-15
			Fair Value	Valuation	Significant			Weighted
	Financial Instruments Owned		(in thousands)	Technique	Unobservable Input(s)	Input/Range		Average
	Corporate equity securities	$	18,210
	Non-exchange traded securities			Market approach	EBITDA (a) multiple	3.5to 8.6		4.4
				Scenario analysis	Estimated recovery percentage	78%		–
	Corporate debt securities	$	24,795	Convertible bond model	Discount rate/yield	32%		–
	Collateralized debt obligations	$	51,095	Discounted cash flows	Constant prepayment rate	0% to 20%		14	%
					Constant default rate	0% to 2%		2	%
					Loss severity	0% to 70%		42	%
					Yield	6% to 20%		13	%
	Residential mortgage-backed securities	$	79,953	Discounted cash flows	Constant prepayment rate	2% to 50%		13	%
					Constant default rate	2% to 100%		21	%
					Loss severity	35% to 80%		52	%
					Yield	1% to 13%		6	%
	Commercial mortgage-backed securities	$	24,629	Discounted cash flows	Yield	8% to 22%		14	%
					Cumulative loss rate	1.9% to 73%		16	%
				Scenario analysis	Estimated recovery percentage	81%		–
	Other asset-backed securities	$	7,146	Discounted cash flows	Constant prepayment rate	4% to 6%		4	%
					Constant default rate	3% to 4%		4	%
					Loss severity	50% to 60%		52	%
					Yield	6% to 7%		6	%
	Loans and other receivables	$	102,034	Comparable pricing	Comparable loan price	$100 to $101	$	100.5
				Market approach	Yield	3% to 9%		7	%
					EBITDA (a) multiple	8.2		–
				Scenario analysis	Estimated recovery percentage	10% to 81%		37	%
				Discounted cash flows	Constant prepayment rate	20%		–
					Constant default rate	2%		–
					Loss severity	25%		–
					Yield	11%		–
	Derivatives	$	46,136
	Foreign exchange options			Option model	Volatility	12% to 23%		15	%
	Commodity forwards			Discounted cash flows	Discount rate	20%		–
	Loan commitments			Comparable pricing	Comparable loan price	$71 to $100	$	99
					Yield	8%		–
	Investments at fair value
	Private equity securities	$	32,312	Market approach	Transaction Level	$57		–
				Market approach	Discount rate	15% to 30%		23	%
	Investment in FXCM	$	310,000	Discounted cash flows	Term based on the pay off	6 months to 1.8 years		0.8	years
	Term loan		637,000	Option pricing model	Volatility	65%		–
	Unfunded commitments	$	947,000					–
			Fair Value	Valuation	Significant			Weighted
	Trading Liabilities		(in thousands)	Technique	Unobservable Input(s)	Input/Range		Average
	Derivatives	$	49,450
	FX options			Option model	Volatility	12% to 23%		15	%
	Unfunded commitments			Comparable pricing	Comparable loan price	$71 to $100	$	78.6
				Market approach	Yield	5% to 8%		8	%
				Discounted cash flows	Constant prepayment rate	20%		–
					Constant default rate	2%		–
					Loss severity	25%		–
					Yield	11%		–
	Loans	$	9,327	Comparable pricing	Comparable loan price	$100		–
	Other secured financings	$	65,602	Comparable pricing	Comparable loan price	$82 to $100	$	98.9
	31-Dec-14
			Fair Value	Valuation	Significant				Weighted
	Financial Instruments Owned		(in thousands)	Technique	Unobservable Input(s)		Input/Range		Average
	Corporate equity securities	$	19,814
	Non-exchange traded securities			Market approach	EBITDA (a) multiple		3.4to 4.7		3.6
				Scenario analysis	Estimated recovery percentage		24%		–
	Corporate debt securities	$	22,766	Convertible bond model	Discount rate/yield		32%		–
	Collateralized debt obligations	$	41,784	Discounted cash flows	Constant prepayment rate		0% to 20%		13	%
					Constant default rate		0% to 2%		2	%
					Loss severity		0% to 70%		39	%
				Yield		2% to 51%		16	%
Residential mortgage-backed securities	$	82,557	Discounted cash flows	Constant prepayment rate		1% to 50%		13	%
				Constant default rate		1% to 100%		14	%
				Loss severity		20% to 80%		50	%
				Yield		3% to 13%		7	%
Commercial mortgage-backed securities	$	26,655	Discounted cash flows	Yield		8% to 12%		11	%
				Cumulative loss rate		4% to 72%		15	%
			Scenario analysis	Estimated recovery percentage		90%		–
Other asset-backed securities	$	2,294	Discounted cash flows	Constant prepayment rate		8%		–
				Constant default rate		3%		–
				Loss severity		70%		–
				Yield		7%		–
Loans and other receivables	$	88,154	Comparable pricing	Comparable loan price		$100 to $101	$	100.3
			Market approach	Yield		3% to 5%		4	%
				EBITDA (a) multiple		3.4to 8.2		7.6
			Scenario analysis	Estimated recovery percentage		10% to 41%		36	%
Derivatives	$	54,190
Foreign exchange options			Option model	Volatility		13% to 23%		17	%
Commodity forwards			Discounted cash flows	Discount rate		17%		–
Loan commitments			Comparable pricing	Comparable loan price		$100		–
Investments at fair value
Private equity securities	$	32,323	Market approach	Transaction Level		$50		–
			Market approach	Discount rate		15% to 30%		23	%
		Fair Value	Valuation	Significant				Weighted
Trading Liabilities		(in thousands)	Technique	Unobservable Input(s)		Input/Range		Average
Derivatives	$	49,552
FX options			Option model	Volatility		13% to 23%		17	%
Unfunded commitments			Comparable pricing	Comparable loan price		$89 to $100	$	92
				Credit spread		45bps		–
			Market approach	Yield		5%		–
Loans	$	14,450	Comparable pricing	Comparable loan price		$100		–
Other secured financings	$	30,825	Comparable pricing	Comparable loan price		$81 to $100	$	98.7
(a) Earnings before interest, taxes, depreciation and amortization ("EBITDA").
Summary Of Gains (Losses) Due To Changes In Instrument Specific Credit Risk For Loans and Other Receivables And Loan Commitments Measured At Fair Value Under Fair Value Option
			2015			2014
	Financial Instruments Owned:
	Loans and other receivables	$	5,389		$	4,467
	Financial Instruments Sold:
	Loans	$	(1,022	)	$	(462	)
	Loan commitments	$	(7,166	)	$	(2,357	)
Summary Of Amount By Which Contractual Principal Exceeds Fair Value For Loans And Other Receivables Measured At Fair Value Under Fair Value Option
			March 31,			December 31,
			2015			2014
	Loans and other receivables (1)	$	426,425		$	403,119
	Loans and other receivables greater than 90 days past due (1)	$	28,829		$	5,594
	Loans and other receivables on nonaccrual status (1) (2)	$	(36,471	)	$	(22,360	)
	(1) Interest income is recognized separately from other changes in fair value and is included within Interest income in the Consolidated Statements of Operations.
	(2) Amounts include all loans and other receivables greater than 90 days past due.

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2015
Derivative Financial Instruments [Abstract]
Unrealized And Realized Gains (Losses) On Derivative Contracts
			2015			2014
	Interest rate contracts	$	(42,793	)	$	(5,118	)
	Foreign exchange contracts		15,172			6,067
	Equity contracts		71,041			(96,236	)
	Commodity contracts		14,491			16,186
	Credit contracts		(6,042	)		(3,878	)
	Total	$	51,869		$	(82,979	)
Remaining Contract Maturity Of Fair Value Of OTC Derivative Assets And Liabilities
		OTC Derivative Assets (1) (2) (3)
									Cross-
							Greater Than		Maturity
			0-12 Months		1-5 Years		5 Years		Netting (4)			Total
	Commodity swaps, options and forwards	$	57,079	$	2,674	$	23,599	$	(2,915	)	$	80,437
	Equity swaps and options		8,894		31,585		5,657		–			46,136
	Credit default swaps		–		–		7,442		(254	)		7,188
	Total return swaps		10,135		377		–		(299	)		10,213
	Foreign currency forwards, swaps and options		376,842		48,591		90		(23,179	)		402,344
	Interest rate swaps, options and forwards		45,809		178,897		125,598		(68,866	)		281,438
	Total	$	498,759	$	262,124	$	162,386	$	(95,513	)		827,756
	Cross product counterparty netting											(21,605	)
	Total OTC derivative assets included in
	Trading assets										$	806,151
	(1) At March 31, 2015, we held exchange traded derivative assets and other credit agreements with a fair value of $67.9 million, which are not included in this table.
	(2) OTC derivative assets in the table above are gross of collateral received. OTC derivative assets are recorded net of collateral received in the Consolidated Statements of Financial Condition. At March 31, 2015 cash collateral received was $377.0 million.
	(3) Derivative fair values include counterparty netting within product category.
	(4) Amounts represent the netting of receivable balances with payable balances for the same counterparty within product category across maturity categories.
		OTC Derivative Liabilities (1) (2) (3)
									Cross-
							Greater Than		Maturity
			0-12 Months		1-5 Years		5 Years		Netting (4)			Total
	Commodity swaps, options and forwards	$	68,406	$	254	$	5,377	$	(2,915	)	$	71,122
	Equity swaps and options		4,670		59,118		19,452		–			83,240
	Credit default swaps		254		6,242		2,103		(254	)		8,345
	Total return swaps		15,733		1,412		–		(299	)		16,846
	Foreign currency forwards, swaps and options		326,435		60,213		–		(23,179	)		363,469
	Fixed income forwards		431		–		–		–			431
	Interest rate swaps, options and forwards		50,381		106,084		143,283		(68,866	)		230,882
	Total	$	466,310	$	233,323	$	170,215	$	(95,513	)		774,335
	Cross product counterparty netting											(21,605	)
	Total OTC derivative liabilities included in
	Trading liabilities										$	752,730
	(1) At March 31, 2015, we held exchange traded derivative liabilities and other credit agreements with a fair value of $28.0 million, which are not included in this table.
	(2) OTC derivative liabilities in the table above are gross of collateral pledged. OTC derivative liabilities are recorded net of collateral pledged in the Consolidated Statements of Financial Condition. At March 31, 2015, cash collateral pledged was $458.4 million.
Counterparty Credit Quality With Respect To Fair Value Of OTC Derivatives Assets
	Counterparty credit quality (1):
	A- or higher	$	508,060
	BBB- to BBB+		107,645
	BB+ or lower		94,772
	Unrated		95,674
	Total	$	806,151
	(1) We utilize internal credit ratings determined by Jefferies Risk Management. Credit ratings determined by Risk Management use methodologies that produce ratings generally consistent with those produced by external rating agencies.

Securitization_Activities_Tabl

Securitization Activities (Tables)	3 Months Ended
	Mar. 31, 2015
Securitization Activities [Abstract]
Activity Related To Securitizations Accounted For As Sales
			2015		2014
	Transferred assets	$	1,562.90	$	1,626.90
	Proceeds on new securitizations		1,564.50		1,628.10
	Cash flows received on retained interests		2.4		8.5
Summary Of Retained Interests In SPEs
			31-Mar-15				31-Dec-14
			Total		Retained		Total		Retained
	Securitization Type		Assets		Interests		Assets		Interests
	U.S. government agency residential mortgage-backed securities	$	11,742.90	$	403.7	$	19,196.90	$	226.9
	U.S. government agency commercial mortgage-backed securities		3,519.50		97.9		5,848.50		204.7
	Collateralized loan obligations		4,169.90		53.3		4,511.80		108.4

Available_For_Sale_Securities_

Available For Sale Securities (Tables)	3 Months Ended
	Mar. 31, 2015
Available For Sale Securities [Abstract]
Amortized Cost, Gross Unrealized Gains And Losses And Estimated Fair Value Of Available For Sale Investments
					Gross		Gross		Estimated
			Amortized		Unrealized		Unrealized		Fair
			Cost		Gains		Losses		Value
	31-Mar-15
	Bonds and notes:
	U.S. government securities	$	213,621	$	3	$	13	$	213,611
	Residential mortgage-backed securities		490,171		9,156		451		498,876
	Commercial mortgage-backed securities		27,534		400		20		27,914
	Other asset-backed securities		130,584		286		362		130,508
	All other corporates		29,410		139		21		29,528
	Total fixed maturities		891,320		9,984		867		900,437
	Equity securities:
	Common stocks:
	Banks, trusts and insurance companies		24,687		14,696		–		39,383
	Industrial, miscellaneous and all other		19,092		15,518		–		34,610
	Total equity securities		43,779		30,214		–		73,993
		$	935,099	$	40,198	$	867	$	974,430
	31-Dec-14
	Bonds and notes:
	U.S. government securities	$	593,803	$	33	$	63	$	593,773
	Residential mortgage-backed securities		597,402		10,959		1,678		606,683
	Commercial mortgage-backed securities		42,991		484		74		43,401
	Other asset-backed securities		245,533		619		996		245,156
	All other corporates		30,519		60		176		30,403
	Total fixed maturities		1,510,248		12,155		2,987		1,519,416
	Equity securities:
	Common stocks:
	Banks, trusts and insurance companies		31,853		18,740		–		50,593
	Industrial, miscellaneous and all other		20,355		18,405		–		38,760
	Total equity securities		52,208		37,145		–		89,353
		$	1,562,456	$	49,300	$	2,987	$	1,608,769
Amortized Cost And Estimated Fair Value Of Investments Classified As Available For Sale By Contractual Maturity
			Amortized		Estimated
			Cost		Fair Value
		(In thousands)
	Due within one year	$	228,255	$	228,292
	Due after one year through five years		14,776		14,847
	Due after five years through ten years		–		–
	Due after ten years		–		–
			243,031		243,139
	Mortgage-backed and asset-backed securities		648,289		657,298
		$	891,320	$	900,437

Variable_Interest_Entities_Tab

Variable Interest Entities (Tables)	3 Months Ended
	Mar. 31, 2015
Variable Interest Entities [Abstract]
Assets And Liabilities Of Consolidated VIEs
		Securitization Vehicles
			March 31,		December 31,
			2015		2014
			(In millions)
	Cash	$	0.4	$	0.5
	Financial instruments owned		65.6		62.7
	Securities purchased under agreement to resell (1)		795.4		575.2
	Other		97.2		107.1
	Total assets	$	958.6	$	745.5
	Other secured financings (2)	$	950.4	$	737
	Other		8.2		8.5
	Total liabilities	$	958.6	$	745.5
	(1) Securities purchased under agreement to resell represent an amount due under a collateralized transaction on a related consolidated entity, which is eliminated in consolidation.
	(2) Approximately $5.6 million and $39.7 million of the secured financing represents an amount held by Jefferies in inventory and eliminated in consolidation at March 31, 2015 and December 31, 2014, respectively.
Non-Consolidated Variable Interest Entities
		Variable Interests
			Financial Statement		Maximum
			Carrying Amount (3)		Exposure to Loss		VIE Assets
			Assets
		(In millions)
	31-Mar-15
	Collateralized loan obligations	$	75.4	$	817.9	$	8,125.20
	Consumer loan financing vehicles		175.3		758.8		411.6
	Asset management vehicles (1)		6		6		199.6
	Private equity vehicles (2)		23.7		48.3		70.8
	Total	$	280.4	$	1,631.00	$	8,807.20
	31-Dec-14
	Collateralized loan obligations	$	134	$	926.9	$	7,737.10
	Consumer loan financing vehicles		170.6		797.8		485.2
	Asset management vehicles (1)		11.3		11.3		432.3
	Private equity vehicles (2)		44.3		59.2		92.8
	Total	$	360.2	$	1,795.20	$	8,747.40
	(1) Assets consist of equity interests, which are included within Investments in managed funds, and accrued management and performance fees, which are included in Receivables.
	(2) Assets consist of equity interests, which are included in Investment in managed funds.
	(3) There were no significant liabilities at March 31, 2015 and December 31, 2014.

Loans_To_And_Investments_In_As1

Loans To And Investments In Associated Companies (Tables)	3 Months Ended
	Mar. 31, 2015
Loans To And Investments In Associated Companies [Abstract]
Schedule Of Investments In Associated Companies
			March 31,		December 31,
			2015		2014
	Jefferies Finance, LLC	$	520,203	$	508,891
	Jefferies LoanCore LLC		301,549		258,947
	Berkadia		219,017		208,511
	Garcadia companies		170,876		167,939
	HomeFed		269,684		271,782
	Linkem S.p.A.		144,813		159,054
	Golden Queen Mining Company, LLC (1)		103,311		103,598
	Other		33,258		33,846
	Total	$	1,762,711	$	1,712,568
	(1) At March 31, 2015 and December 31, 2014, the balance reflects $33.6 million and $33.7 million, respectively, related to a noncontrolling interest.
Schedule Of Income (Losses) Related To Associated Companies
			2015			2014
	Berkadia	$	32,343		$	13,973
	Garcadia companies		15,253			11,259
	Linkem		(4,788	)		(5,836	)
	HomeFed		(2,098	)		(618	)
	Golden Queen		(287	)		–
	Other		28			1,258
	Total	$	40,451		$	20,036
Schedule Of Income (Losses) Related To Associated Companies Classified As Other Revenue
			2015			2014
	Jefferies Finance	$	11,311		$	17,601
	Jefferies LoanCore		9,858			2,482
	Other		(480	)		544
	Total	$	20,689		$	20,627

Financial_Statement_Offsetting1

Financial Statement Offsetting (Tables)	3 Months Ended
	Mar. 31, 2015
Financial Statement Offsetting [Abstract]
Summary Of Offsetting Assets And Liabilities
					Netting in			Net Amounts in
					Consolidated			Consolidated		Additional
					Statement of			Statement of		Amounts
			Gross		Financial			Financial		Available for			Available
	(In thousands)		Amounts		Condition			Condition		Setoff (1)			Collateral (2)			Net Amount (3)
	Assets at March 31, 2015
	Derivative contracts	$	5,226,625	$	(4,729,533	)	$	497,092	$	–		$	–		$	497,092
	Securities borrowing arrangements	$	6,566,376	$	–		$	6,566,376	$	(526,142	)	$	(766,832	)	$	5,273,402
	Reverse repurchase agreements	$	11,109,009	$	(7,363,321	)	$	3,745,688	$	(236,325	)	$	(3,450,577	)	$	58,786
	Liabilities at March 31, 2015
	Derivative contracts	$	5,133,092	$	(4,810,751	)	$	322,341	$	–		$	–		$	322,341
	Securities lending arrangements	$	3,173,512	$	–		$	3,173,512	$	(526,142	)	$	(2,616,154	)	$	31,216
	Repurchase agreements	$	18,686,688	$	(7,363,321	)	$	11,323,367	$	(236,325	)	$	(10,039,131	)	$	1,047,911
	Assets at December 31, 2014
	Derivative contracts	$	5,165,613	$	(4,759,345	)	$	406,268	$	–		$	–		$	406,268
	Securities borrowing arrangements	$	6,853,103	$	–		$	6,853,103	$	(680,222	)	$	(1,274,196	)	$	4,898,685
	Reverse repurchase agreements	$	14,059,133	$	(10,132,275	)	$	3,926,858	$	(634,568	)	$	(3,248,817	)	$	43,473
	Liabilities at December 31, 2014
	Derivative contracts	$	5,220,133	$	(4,856,618	)	$	363,515	$	–		$	–		$	363,515
	Securities lending arrangements	$	2,598,487	$	–		$	2,598,487	$	(680,222	)	$	(1,883,140	)	$	35,125
	Repurchase agreements	$	20,804,432	$	(10,132,275	)	$	10,672,157	$	(634,568	)	$	(8,810,770	)	$	1,226,819
	(1) Under master netting agreements with our counterparties, we have the legal right of offset with a counterparty, which incorporates all of the counterparty's outstanding rights and obligations under the arrangement. These balances reflect additional credit risk mitigation that is available by counterparty in the event of a counterparty's default, but which are not netted in the balance sheet because other provisions of GAAP are not met. Further, for derivative assets and liabilities, amounts netted include cash collateral paid or received.

Intangible_Assets_Net_And_Good1

Intangible Assets, Net And Goodwill (Tables)	3 Months Ended
	Mar. 31, 2015
Intangible Assets, Net And Goodwill [Abstract]
Schedule Of Intangible Assets, Net And Goodwill
			March 31,		December 31,
			2015		2014
	Indefinite-lived intangibles:
	Exchange and clearing organization membership interests and registrations	$	14,501	$	14,528
	Amortizable intangibles:
	Customer and other relationships, net of accumulated amortization of
	$165,060 and $155,548		483,408		493,501
	Trademarks and tradename, net of accumulated amortization of $51,254
	and $47,101		343,459		347,883
	Supply contracts, net of accumulated amortization of $32,997 and $30,433		116,998		119,562
	Other, net of accumulated amortization of $4,808 and $4,703		2,795		2,900
	Total intangible assets, net		961,161		978,374
	Goodwill:
	National Beef		14,991		14,991
	Jefferies		1,717,595		1,718,847
	Other operations		8,551		8,551
	Total goodwill		1,741,137		1,742,389
	Total intangible assets, net and goodwill	$	2,702,298	$	2,720,763

Inventory_Tables

Inventory (Tables)	3 Months Ended
	Mar. 31, 2015
Inventory [Abstract]
Summary Of Inventory
			March 31,		December 31,
			2015		2014
	Finished goods	$	364,875	$	343,959
	Work in process		40,773		40,951
	Raw materials, supplies and other		39,184		37,993
		$	444,832	$	422,903

LongTerm_Debt_Tables

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2015
Long-Term Debt [Abstract]
Schedule Of Indebtedness
			March 31,		December 31,
			2015		2014
	Parent Company Debt:
	Senior Notes:
	8.125% Senior Notes due September 15, 2015, $458,641 principal	$	458,040	$	457,723
	5.50% Senior Notes due October 18, 2023, $750,000 principal		740,953		740,748
	6.625% Senior Notes due October 23, 2043, $250,000 principal		247,000		246,991
	Total long-term debt – Parent Company		1,445,993		1,445,462
	Subsidiary Debt (non-recourse to Parent Company):
	Jefferies:
	3.875% Senior Notes, due November 9, 2015, $500,000 principal		505,851		507,944
	5.5% Senior Notes, due March 15, 2016, $350,000 principal		360,702		363,229
	5.125% Senior Notes, due April 13, 2018, $800,000 principal		839,383		842,359
	8.5% Senior Notes, due July 15, 2019, $700,000 principal		826,229		832,797
	2.375% Euro Senior Notes, due May 20, 2020, $559,850 principal		558,601		620,725
	6.875% Senior Notes, due April 15, 2021, $750,000 principal		849,568		853,091
	2.25% Euro Medium Term Notes, due July 13, 2022, $4,479 principal		3,956		4,379
	5.125% Senior Notes, due January 20, 2023, $600,000 principal		622,716		623,311
	6.45% Senior Debentures, due June 8, 2027, $350,000 principal		381,073		381,515
	3.875% Convertible Senior Debentures, due November 1, 2029,
	$345,000 principal		348,276		348,568
	6.25% Senior Debentures, due January 15, 2036, $500,000 principal		512,969		513,046
	6.50% Senior Notes, due January 20, 2043, $400,000 principal		421,885		421,960
	Secured credit facility, due June 26, 2017		205,000		170,000
	National Beef Term Loan		336,250		345,000
	National Beef Revolving Credit Facility		181,916		135,144
	Other		158,415		119,399
	Total long-term debt – subsidiaries		7,112,790		7,082,467
	Long-term debt	$	8,558,783	$	8,527,929

Mezzanine_Equity_Tables

Mezzanine Equity (Tables)	3 Months Ended
	Mar. 31, 2015
Mezzanine Equity [Abstract]
Schedule Of Redeemable Noncontrolling Interests
			2015			2014
	As of January 1,	$	184,333		$	241,075
	Loss allocated to redeemable noncontrolling
	interests		(7,059	)		(5,939	)
	Decrease in fair value of redeemable noncontrolling
	interests credited to additional paid-in capital		(11,033	)		(755	)
	Balance, March 31,	$	166,241		$	234,381
Sensitivity Analysis Of Fair Value Of Redeemable Noncontrolling Interests Using Discount And Terminal Growth Rates
		Discount Rates
	Terminal Growth Rates		12.75%		13.00%		13.25%
	1.75%	$	170	$	164.2	$	158.6
	2.00%	$	172.2	$	166.2	$	160.5
	2.25%	$	174.5	$	168.4	$	162.5

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	3 Months Ended
	Mar. 31, 2015
Accumulated Other Comprehensive Income [Abstract]
Summary Of Accumulated Other Comprehensive Income, Net Of Taxes
			March 31,			December 31,
			2015			2014
	Net unrealized gains on available for sale securities	$	571,170		$	577,588
	Net unrealized foreign exchange losses		(41,492	)		(26,771	)
	Net minimum pension liability		(102,560	)		(103,735	)
		$	427,118		$	447,082
Schedule Of Accumulated Other Comprehensive Income Reclassifications
	Details about Accumulated Other		Amount Reclassified from					Affected Line Item in the
	Comprehensive Income		Accumulated Other					Consolidated Statements
	Components		Comprehensive Income					of Operations
			2015			2014
	Net unrealized gains (losses) on available for							Net realized securities gains
	sale securities, net of income tax provision
	(benefit) of $2,944 and $(488)	$	5,303		$	(878	)
	Amortization of defined benefit pension							Compensation and benefits, which
	plan actuarial gains (losses), net of							includes pension expense. See the
	income tax benefit of $(653)							pension footnote for information
	and $(422)		(1,175	)		(760	)	on this component.
	Total reclassifications for the period,
	net of tax	$	4,128		$	(1,638	)

Pension_Plans_And_Postretireme1

Pension Plans And Postretirement Benefits (Tables)	3 Months Ended
	Mar. 31, 2015
Pension Plans And Postretirement Benefits [Abstract]
Components Of Pension Expense
			2015			2014
	Components of net periodic pension cost:
	Interest cost	$	3,476		$	3,774
	Service cost		–			11
	Expected return on plan assets		(2,690	)		(2,536	)
	Actuarial losses		1,912			1,208
	Net periodic pension cost	$	2,698		$	2,457

Earnings_Loss_Per_Common_Share1

Earnings (Loss) Per Common Share (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings (Loss) Per Common Share [Abstract]
Earnings Per Share Computation
			2015			2014
	Numerator for earnings (loss) per share:
	Net income attributable to Leucadia
	National Corporation common shareholders	$	380,759		$	94,316
	Allocation of earnings to participating securities (1)		(7,086	)		(2,397	)
	Net income attributable to Leucadia
	National Corporation common shareholders for
	basic earnings (loss) per share		373,673			91,919
	Adjustment to allocation of earnings to participating
	securities related to diluted shares (1)		54			–
	Mandatorily redeemable convertible preferred share
	dividends		1,016			1,016
	Interest on 3.75% Convertible Notes		–			640
	Net income attributable to Leucadia
	National Corporation common shareholders for
	diluted earnings (loss) per share	$	374,743		$	93,575
	Denominator for earnings (loss) per share:
	Denominator for basic earnings (loss) per share –
	weighted average shares		373,541			368,487
	Stock options		10			101
	Warrants		–			–
	Mandatorily redeemable convertible preferred shares		4,162			4,162
	3.875% Convertible Senior Debentures		–			–
	3.75% Convertible Notes		–			4,598
	Denominator for diluted earnings (loss) per share		377,713			377,348
	(1) Represents dividends declared during the period on participating securities plus an allocation of undistributed earnings to participating securities. Net losses are not allocated to participating securities. Participating securities represent restricted stock and RSUs for which requisite service has not yet been rendered and amounted to weighted average shares of 7,114,000 and 9,704,400 for the three months ended March 31, 2015 and 2014, respectively.

Recovered_Sheet1

Commitments, Contingencies and Guarantees (Tables)	3 Months Ended
	Mar. 31, 2015
Commitments, Contingencies And Guarantees [Abstract]
Commitments and Contingencies
		Expected Maturity Date
							2017		2019		2021
							and		and		and		Maximum
			2015		2016		2018		2020		Later		Payout
	Equity commitments (1)	$	–	$	9.2	$	0.8	$	–	$	171.8	$	181.8
	Loan commitments (1)		44.6		421.7		188.9		48.3		–		703.5
	Mortgage-related and other purchase
	commitments		1,123.10		1,315.60		126.2		–		–		2,564.90
	Forward starting reverse repos and repos		2,034.90		–		–		–		–		2,034.90
	Other unfunded commitments (1)		30		–		–		–		21.9		51.9
		$	3,232.60	$	1,746.50	$	315.9	$	48.3	$	193.7	$	5,537.00
	(1) Equity, loan and other unfunded commitments are presented by contractual maturity date. The amounts are however available on demand.
Credit Exposure From Loan Commitments
									Total		Corporate		Corporate
							Greater		Corporate		Lending		Lending
			0 - 12		5-Jan		Than		Lending		Exposure at		Commitments
	Credit Ratings		Months		Years		5 Years		Exposure (1)		Fair Value (2)		-3
	Non-investment grade	$	–	$	167.6	$	–	$	167.6	$	2.8	$	164.8
	Unrated		128		643		–		771		232.3		538.7
	Total	$	128	$	810.6	$	–	$	938.6	$	235.1	$	703.5
	(1) Total corporate lending exposure represents the potential loss assuming the fair value of funded loans and lending commitments were zero.
Guarantees
					Expected Maturity Date
							2017		2019		2021		Notional/
							and		and		and		Maximum
	Guarantee Type		2015		2016		2018		2020		Later		Payout
	Derivative contracts – non-credit related	$	37,182.40	$	2,241.60	$	561.4	$	699.1	$	438.9	$	41,123.40
	Written derivative contracts – credit
	related		2		–		–		2,762.20		84		2,848.20
	Total derivative contracts	$	37,184.40	$	2,241.60	$	561.4	$	3,461.30	$	522.9	$	43,971.60
External Credit Ratings of Underlying or Referenced Assets for Credit Related Derivatives Contracts
		External Credit Rating
											Below				Notional/
			AAA/		AA/						Investment				Maximum
			Aaa		Aa		A		BBB/Baa		Grade		Unrated		Payout
	Credit related derivative contracts:
	Index credit default swaps	$	2,772.20	$	–	$	–	$	–	$	–	$	–	$	2,772.20
	Single name credit default swaps	$	–	$	–	$	–	$	12	$	64	$	–		76

Net_Capital_Requirements_Table

Net Capital Requirements (Tables)	3 Months Ended
	Mar. 31, 2015
Net Capital Requirements [Abstract]
Net Capital, Adjusted Net Capital And Excess Net Capital
					Excess
			Net Capital		Net Capital
	Jefferies LLC	$	954,261	$	837,399
	Jefferies Execution		7,132		6,882

Other_Fair_Value_Information_T

Other Fair Value Information (Tables)	3 Months Ended
	Mar. 31, 2015
Other Fair Value Information [Abstract]
Methods And Assumptions Used To Estimate The Fair Values
			31-Mar-15				31-Dec-14
			Carrying		Fair		Carrying		Fair
			Amount		Value		Amount		Value
	Other Assets:
	Notes and loans receivable (a)	$	249,385	$	262,956	$	213,174	$	217,171
	Financial Liabilities:
	Short-term borrowings (b)		411,998		411,998		12,000		12,000
	Long-term debt (b)		8,558,783		8,662,603		8,527,929		8,806,700
	(a) Notes and loans receivable: The fair values are primarily measured using Level 2 and 3 inputs principally based on discounted future cash flows using market interest rates for similar instruments.
	(b) Short-term borrowings and long-term debt: The fair values of short-term borrowings are estimated to be the carrying amount. The fair values of non-variable rate debt are estimated using quoted prices and estimated rates that would be available for debt with similar terms. The fair value of variable rate debt is estimated to be the carrying amount.

Discontinued_Operations_Tables

Discontinued Operations (Tables)	3 Months Ended
	Mar. 31, 2015
Discontinued Operations [Abstract]
Results Of Discontinued Operations
	Revenues and other income:
	Gaming entertainment	$	31,004
	Investment and other income		810
			31,814
	Expenses:
	Direct operating expenses – Gaming
	entertainment		23,429
	Compensation and benefits		1,172
	Depreciation and amortization		2,224
	Selling, general and other expenses		18,694
			45,519
	Loss from discontinued
	operations before income taxes		(13,705	)
	Income tax (benefit)		(4,796	)
	Loss from discontinued operations after income taxes	$	(8,909	)

Segment_Information_Tables

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2015
Segment Information [Abstract]
Schedule Of Segment Reporting Information, By Segment
			2015			2014
			(In thousands)
	Net Revenues:
	Reportable Segments:
	Jefferies	$	591,441		$	930,512
	National Beef		1,856,019			1,887,378
	Corporate and other		20,316			13,684
	Total net revenues related to reportable
	segments		2,467,776			2,831,574
	All other		737,907			110,950
	Intercompany eliminations		(21,000	)		–
	Total consolidated net revenues	$	3,184,683		$	2,942,524
	Pre-tax income (loss) from continuing
	operations:
	Reportable Segments:
	Jefferies	$	12,924		$	196,370
	National Beef		(33,585	)		(28,013	)
	Corporate and other		(9,864	)		(19,231	)
	Pre-tax income (loss) from continuing
	operations related to reportable segments		(30,525	)		149,126
	All other		641,932			33,147
	Parent Company interest		(24,300	)		(25,177	)
	Total consolidated pre-tax income from
	continuing operations	$	587,107		$	157,096
	Depreciation and amortization expenses:
	Reportable Segments:
	Jefferies	$	22,250		$	17,031
	National Beef		21,787			20,760
	Corporate and other		970			1,337
	Total depreciation and amortization
	expenses related to reportable segments		45,007			39,128
	All other		7,433			2,359
	Total consolidated depreciation and
	amortization expenses	$	52,440		$	41,487

Subsequent_Events_Tables

Subsequent Events (Tables)	3 Months Ended
	Mar. 31, 2015
Subsequent Events [Abstract]
Schedule Of Termination Costs
		(In millions)
	Compensation and benefits (including severance costs,
	retention awards and amortization expense for existing
	restricted stock and restricted cash compensation awards)	$	39.8
	Accelerated capitalized software amortization		20.8
	Technology and communications service agreements		24.5
	Impairment of exchange memberships		2.5
	Other expenses		3.6
	Total	$	91.2

Nature_Of_Operations_Details

Nature Of Operations (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Jan. 31, 2015	7-May-15
National Beef [Member]
Nature Of Operations [Line Items]
Percentage interest owned in subsidiary	78.90%
Idaho Timber [Member]
Nature Of Operations [Line Items]
Domestic facilities	10
Conwed Plastics [Member]
Nature Of Operations [Line Items]
Foreign facilities	1
Domestic facilities	4
Berkadia [Member]
Nature Of Operations [Line Items]
Percentage of ownership owned	50.00%
Garcadia [Member]
Nature Of Operations [Line Items]
Number of automobile dealerships	26
HomeFed Corporation [Member]
Nature Of Operations [Line Items]
Percentage of ownership owned	65.00%
Linkem [Member]
Nature Of Operations [Line Items]
Percentage of ownership owned	42.00%
Percentage of ownership upon conversion of note	55.00%
HRG [Member]
Nature Of Operations [Line Items]
Percentage of outstanding common stock owned	23.00%	23.00%
Number of operating segments	4
Golden Queen Mining Company, LLC [Member]
Nature Of Operations [Line Items]
Percentage of ownership owned	34.00%
Jefferies LoanCore [Member]
Nature Of Operations [Line Items]
Percentage of ownership owned	48.50%
Jefferies Finance [Member]
Nature Of Operations [Line Items]
Percentage of ownership owned	50.00%
FXCM [Member]
Nature Of Operations [Line Items]
Senior secured term loan receivable	287.6		$300
FXCM [Member] | Subsequent Event [Member]
Nature Of Operations [Line Items]
Senior secured term loan receivable				$228.40
Beef Processing Facility [Member] | National Beef [Member]
Nature Of Operations [Line Items]
Domestic facilities	2
Consumer-Ready Facility [Member] | National Beef [Member]
Nature Of Operations [Line Items]
Domestic facilities	3
Tanning Facility [Member] | National Beef [Member]
Nature Of Operations [Line Items]
Domestic facilities	1

Basis_Of_Presentation_And_Sign2

Basis Of Presentation And Significant Accounting Policies (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Basis Of Presentation And Significant Accounting Policies [Abstract]
Receivables from brokers, dealers and clearing organizations	$2,222.30	$2,187.50
Receivables from customers of securities operations	1,343.60	1,250.50
Payables to brokers, dealers and clearing organizations	2,663	2,280.10
Payables to customers of securities operations	$4,757.50	$6,242

Fair_Value_Disclosures_Narrati

Fair Value Disclosures (Narrative) (Details) (USD $)	3 Months Ended		1 Months Ended	0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Jan. 31, 2015	7-May-15	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Carrying Value of Senior Secured Term Loan receivable and rights to future distributions	$947,000,000
Unrealized and realized gains and interest income	729,235,000	281,054,000
Transfers of assets from Level 2 to Level 3	205,200,000	91,000,000
Transfers of assets from Level 3 to Level 2	110,300,000	47,300,000
Net gains (losses) on Level 3 assets (realized and unrealized)	638,600,000	20,300,000
Net gains (losses) on Level 3 liabilities (realized and unrealized)	-6,900,000	-1,100,000
Transfers of loans accounted for as secured financings	5,600,000				7,800,000
Excluded assets from unobservable quantitative information	618,500,000				180,000,000
Excluded liabilities from unobservable quantitative information	0				300,000
Financial instruments owned trading assets, at fair value	20,971,087,000				19,612,490,000
Non-Agency Residential Mortgage-Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	35,300,000	38,100,000
Transfers of assets from Level 3 to Level 2	35,700,000	19,100,000
Commercial Mortgage-Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	10,300,000	9,000,000
Transfers of assets from Level 3 to Level 2	4,500,000	200,000
Corporate Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	1,700,000	7,400,000
Transfers of assets from Level 3 to Level 2	4,400,000	3,600,000
Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	2,400,000	2,300,000
Transfers of assets from Level 3 to Level 2	25,600,000	200,000
Collateralized Debt Obligations [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	64,500,000	23,500,000
Transfers of assets from Level 3 to Level 2	34,300,000	3,300,000
Other Asset-Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	5,000,000	1,800,000
Transfers of assets from Level 3 to Level 2		12,200,000
Loans And Other Receivables [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	16,400,000	8,900,000
Transfers of assets from Level 3 to Level 2	5,700,000	7,900,000
Investments At Fair Value [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	69,200,000
Transfers of assets from Level 3 to Level 2		800,000
KCG Holdings [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Changes in fair value of investments reflected as principal transactions	34,600,000	-1,000,000
Jefferies [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Changes in fair value of investments reflected as principal transactions		19,900,000
HRG [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Cash consideration paid for shares	475,600,000
Changes in fair value of investments reflected as principal transactions	-78,300,000	32,600,000
Shares owned, number	46,600,000				46,600,000
Percentage of outstanding common stock owned	23.00%				23.00%
Number of directors appointed	2
Maximum ownership percentage	27.50%
Restriction on sale, maximum percentage	4.90%
Financial instruments owned trading assets, at fair value	581,600,000				659,900,000
FXCM [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Senior secured term loan receivable	287,600,000		300,000,000
Loan receivable interest rate percentage			10.00%
Increase in Interest rate per annum each quarter			1.50%
Percentage of distributions from sale of assets or certain other events until loan repayment			100.00%
Percentage of distributions from sale of assets or certain other events until next milestone amount			50.00%
Distributions milestone after loan repayment			350,000,000
Percentage of distributions from sale of assets or certain other events until next milestone as a percentage of balance outstanding			90.00%
Multiple of loan outstanding			2
Percentage of distributions from sale of assets or certain other events thereafter			60.00%
Principal and interest payments received	18,600,000
Carrying Value of Senior Secured Term Loan receivable and rights to future distributions	947,000,000
Unrealized and realized gains and interest income	686,600,000
Assumed change in price of shares	$0.30
Percentage of market price	14.00%
Change in market value as a result of assumed change in price per share	51,000,000
Change in assumed volatility	10.00%
Change in market value as a result of change in assumed volatility	29,000,000
FXCM [Member] | Subsequent Event [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Senior secured term loan receivable				228,400,000
Principal and interest payments received				69,300,000
Net Derivatives, Liabilities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Transfers of liabilities from Level 3 to Level 2		3,400,000
Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Transfers of liabilities from Level 2 to Level 3		4,800,000
Transfers of liabilities from Level 3 to Level 2	3,000,000	2,900,000
Other Merchant Banking Businesses [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Changes in fair value of investments reflected as principal transactions		12,700,000
Minimum [Member] | FXCM [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance outstanding used to calculate percentage of distributions from sale of assets or certain other events			500,000,000
Maximum [Member] | FXCM [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Loan receivable interest rate percentage			20.50%
Balance outstanding used to calculate percentage of distributions from sale of assets or certain other events			$680,000,000

Fair_Value_Disclosures_Schedul

Fair Value Disclosures (Schedule Of Assets And Liabilities Measured On Recurring Basis At Fair Value) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	$497,092,000		$406,268,000
Derivatives	-4,729,533,000		-4,759,345,000
Investment in FXCM	947,000,000
Total trading assets	20,971,087,000		19,612,490,000
Total available for sale securities	974,430,000		1,608,769,000
Cash and cash equivalents	3,524,524,000		4,276,775,000
Investments in managed funds	593,581,000		281,470,000
Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations	3,186,319,000	[1]	3,444,674,000	[1]
Securities received as collateral	4,821,000		5,418,000
Derivatives	322,341,000		363,515,000
Derivatives	-4,810,751,000		-4,856,618,000
Total trading liabilities	7,945,501,000		8,904,592,000
Other secured financings	65,602,000		30,825,000
Obligation to return securities received as collateral	4,821,000		5,418,000
U.S. government securities segregated for regulatory purposes	434,800,000		453,700,000
Money market funds	810,000,000		545,000,000
Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	2,091,085,000		2,009,188,000
Corporate debt securities	1,766,453,000		1,612,217,000
Collateralized debt obligations			4,557,000
U.S. government and federal agency securities	1,466,111,000		2,253,055,000
Sovereign obligations	1,367,690,000		1,791,085,000
Loans	919,896,000		870,975,000
Derivatives	322,341,000		363,515,000
Fair value, equity options transferred from Level 1 to Level 2			6,600,000
Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	3,279,888,000		3,378,297,000
Corporate debt securities	3,429,984,000		3,398,194,000
Collateralized debt obligations	244,797,000		397,716,000
U.S. government and federal agency securities	3,890,072,000		2,775,541,000
Municipal securities	772,940,000		590,849,000
Sovereign obligations	2,580,183,000		2,759,511,000
Loans and other receivables	1,460,611,000		1,556,018,000
Derivatives	497,092,000		406,268,000
Investments at fair value	193,097,000		192,364,000
Physical commodities	58,715,000		62,234,000
Fair value, equity options transferred from Level 1 to Level 2			6,100,000
Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	73,993,000		89,353,000
Corporate debt securities	29,528,000		30,403,000
U.S. government and federal agency securities	213,611,000		593,773,000
Residential Mortgage-Backed Securities [Member] | Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, liabilities	11,925,000
Residential Mortgage-Backed Securities [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	2,904,453,000		2,962,511,000
Residential Mortgage-Backed Securities [Member] | Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	498,876,000		606,683,000
Commercial Mortgage-Backed Securities [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	566,718,000		993,306,000
Commercial Mortgage-Backed Securities [Member] | Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	27,914,000		43,401,000
Other Asset-Backed Securities [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	145,537,000		139,681,000
Other Asset-Backed Securities [Member] | Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	130,508,000		245,156,000
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total trading assets	8,454,872,000	[2]	7,859,052,000	[2]
Total available for sale securities	287,604,000	[2]	683,126,000	[2]
Cash and cash equivalents	3,524,524,000	[2]	4,276,775,000	[2]
Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations	3,186,319,000	[1],[2]	3,444,674,000	[1],[2]
Securities received as collateral	4,821,000	[2]	5,418,000	[2]
Total trading liabilities	4,177,253,000	[2]	5,457,377,000	[2]
Obligation to return securities received as collateral	4,821,000	[2]	5,418,000	[2]
Level 1 [Member] | Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	2,031,013,000	[2]	1,934,469,000	[2]
U.S. government and federal agency securities	1,366,689,000	[2]	2,253,055,000	[2]
Sovereign obligations	707,844,000	[2]	1,217,075,000	[2]
Derivatives	71,707,000	[2]	52,778,000	[2]
Level 1 [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	3,052,340,000	[2]	3,130,892,000	[2]
U.S. government and federal agency securities	3,783,645,000	[2]	2,694,268,000	[2]
Sovereign obligations	1,522,227,000	[2]	1,968,747,000	[2]
Derivatives	96,660,000	[2]	65,145,000	[2]
Level 1 [Member] | Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	73,993,000	[2]	89,353,000	[2]
U.S. government and federal agency securities	213,611,000	[2]	593,773,000	[2]
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total trading assets	15,696,205,000	[2]	15,962,237,000	[2]
Total available for sale securities	686,826,000	[2]	925,643,000	[2]
Investments in managed funds	160,456,000	[2]	226,488,000	[2]
Total trading liabilities	8,520,184,000	[2]	8,239,570,000	[2]
Level 2 [Member] | Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	60,034,000	[2]	74,681,000	[2]
Corporate debt securities	1,766,453,000	[2]	1,611,994,000	[2]
Collateralized debt obligations			4,557,000	[2]
U.S. government and federal agency securities	99,422,000	[2]
Sovereign obligations	659,846,000	[2]	574,010,000	[2]
Loans	910,569,000	[2]	856,525,000	[2]
Derivatives	5,011,935,000	[2]	5,117,803,000	[2]
Level 2 [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	209,338,000	[2]	226,441,000	[2]
Corporate debt securities	3,399,249,000	[2]	3,342,276,000	[2]
Collateralized debt obligations	153,900,000	[2]	306,218,000	[2]
U.S. government and federal agency securities	106,427,000	[2]	81,273,000	[2]
Municipal securities	772,940,000	[2]	590,849,000	[2]
Sovereign obligations	1,057,623,000	[2]	790,764,000	[2]
Loans and other receivables	1,349,201,000	[2]	1,458,760,000	[2]
Derivatives	5,083,829,000	[2]	5,046,278,000	[2]
Investments at fair value	3,000	[2]	73,152,000	[2]
Physical commodities	58,715,000	[2]	62,234,000	[2]
Level 2 [Member] | Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate debt securities	29,528,000	[2]	30,403,000	[2]
Level 2 [Member] | Residential Mortgage-Backed Securities [Member] | Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, liabilities	11,925,000	[2]
Level 2 [Member] | Residential Mortgage-Backed Securities [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	2,824,500,000	[2]	2,879,954,000	[2]
Level 2 [Member] | Residential Mortgage-Backed Securities [Member] | Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	498,876,000	[2]	606,683,000	[2]
Level 2 [Member] | Commercial Mortgage-Backed Securities [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	542,089,000	[2]	966,651,000	[2]
Level 2 [Member] | Commercial Mortgage-Backed Securities [Member] | Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	27,914,000	[2]	43,401,000	[2]
Level 2 [Member] | Other Asset-Backed Securities [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	138,391,000	[2]	137,387,000	[2]
Level 2 [Member] | Other Asset-Backed Securities [Member] | Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	130,508,000	[2]	245,156,000	[2]
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in FXCM	947,000,000
Total trading assets	1,549,543,000		550,546,000
Investments in managed funds	433,125,000		54,982,000
Total trading liabilities	58,815,000		64,263,000
Other secured financings	65,602,000		30,825,000
Level 3 [Member] | Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	38,000		38,000
Corporate debt securities			223,000
Loans	9,327,000		14,450,000
Derivatives	49,450,000		49,552,000
Level 3 [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	18,210,000		20,964,000
Corporate debt securities	30,735,000		55,918,000
Collateralized debt obligations	90,897,000		91,498,000
Sovereign obligations	333,000
Loans and other receivables	111,410,000		97,258,000
Derivatives	46,136,000		54,190,000
Investments at fair value	193,094,000		119,212,000
Level 3 [Member] | Residential Mortgage-Backed Securities [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	79,953,000		82,557,000
Level 3 [Member] | Commercial Mortgage-Backed Securities [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	24,629,000		26,655,000
Level 3 [Member] | Other Asset-Backed Securities [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	7,146,000		2,294,000
Counterparty And Cash Collateral Netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total trading assets	-4,729,533,000	[3]	-4,759,345,000	[3]
Total trading liabilities	-4,810,751,000	[3]	-4,856,618,000	[3]
Counterparty And Cash Collateral Netting [Member] | Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	-4,810,751,000	[3]	-4,856,618,000	[3]
Counterparty And Cash Collateral Netting [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	($4,729,533,000)	[3]	($4,759,345,000)	[3]
[1]	Securities comprise U.S. government securities segregated for regulatory purposes with a fair value of $434.8 million and $453.7 million at March 31, 2015 and December 31, 2014, respectively, and Commodities Futures Trading Commission ("CFTC") approved money market funds with a fair value of $810.0 million and $545.0 million at March 31, 2015 and December 31, 2014, respectively.
[2]	There were no transfers between Level 1 and Level 2 during the three months ended March 31, 2015. During the year ended December 31, 2014, equity options presented within Trading assets and Trading liabilities of $6.1 million and $6.6 million, respectively, were transferred from Level 1 to Level 2 as adjustments were incorporated into the valuation approach for such contracts to estimate the point within the bid-ask range that meets the best estimate of fair value.
[3]	Represents counterparty and cash collateral netting across the levels of the fair value hierarchy for positions with the same counterparty.

Fair_Value_Disclosures_Investm

Fair Value Disclosures (Investments Measured At Fair Value Based On Net Asset Value) (Details) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$632,861	[1],[2]	$321,186	[1],[2]
Unfunded commitments	25,764	[2]	26,117	[2]
Equity Long/Short Hedge Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	480,302	[1],[3]	146,134	[1],[3]
Redemption Frequency (if currently eligible)		[3]	Monthly/Quarterly	[3]
High Yield Hedge Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	196	[1],[4]	204	[1],[4]
Fund Of Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	340	[1],[5]	323	[1],[5]
Unfunded commitments	94	[5]	94	[5]
Equity Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	40,403	[1],[6]	65,216	[1],[6]
Unfunded commitments	25,670	[6]	26,023	[6]
Convertible Bond Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	3,470	[1],[7]	3,355	[1],[7]
Redemption Frequency (if currently eligible)	At Will	[7]	At Will	[7]
Multi-Strategy Fund [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$108,150	[1],[8]	$105,954	[1],[8]
[1]	Where fair value is calculated based on net asset value, fair value has been derived from each of the funds' capital statements.
[2]	Investments at fair value in the Consolidated Statements of Financial Condition at March 31, 2015 and December 31, 2014, include $153.8 million and $152.6 million, respectively, of direct investments which do not have the characteristics of investment companies and therefore not included within this table.
[3]	This category includes investments in hedge funds that invest, long and short, in equity securities in domestic and international markets in both the public and private sectors. At March 31, 2015, investments with a fair value of $78.0 million and at December 31, 2014 substantially all of the investments in this category are redeemable with 30 to 90 days prior written notice, and includes an investment in a private asset management fund managed by us with a fair value of $48.8 million and $117.2 million at March 31, 2015 and December 31, 2014, respectively. At March 31, 2015, this category also includes investments in two Folger Hill feeder funds that invest solely in a Folger Hill master fund that makes long/short equity investments, with broad industry and geographic diversification. Investment in these funds is subject to a lock-up until August 15, 2019, subject to certain release events and other withdrawal rights. Following this date, investments can be redeemed as of any calendar quarter-end with no less than 45 calendar days' notice, subject to certain limitations. At March 31, 2015, our investments in these two funds had an aggregate fair value of $402.3 million.
[4]	Includes investments in funds that invest in domestic and international public high yield debt, private high yield investments, senior bank loans, public leveraged equities, distressed debt, and private equity investments. There are no redemption provisions. The underlying assets of the funds are being liquidated and we are unable to estimate when the underlying assets will be fully liquidated.
[5]	Includes investments in fund of funds that invest in various private equity funds. At March 31, 2015 and December 31, 2014, approximately 96% and 95%, respectively, of the fair value of investments in this category is managed by us and has no redemption provisions, instead distributions are received through the liquidation of the underlying assets of the fund of funds, which are estimated to be liquidated in approximately two years. For the remaining investments, we have requested redemption; however, we are unable to estimate when these funds will be received.
[6]	At March 31, 2015 and December 31, 2014, investments representing approximately 99% and 99%, respectively, of the fair value of investments in this category include investments in equity funds that invest in the equity of various U.S. and foreign private companies in the energy, technology, internet service and telecommunication service industries. These investments cannot be redeemed; instead distributions are received through the liquidation of the underlying assets of the funds which are expected to liquidate in one to eight years. The remaining investments are in liquidation and we are unable to estimate when the underlying assets will be fully liquidated.
[7]	Investment in the Jefferies Umbrella Fund, an open-ended investment company managed by us that invests primarily in convertible bonds. The investment is redeemable with five days prior written notice.
[8]	Investment in private asset management fund managed by us that employs a variety of investment strategies and can invest in U.S. and non-U.S. equity and equity related securities, futures, exchange traded funds, fixed income securities, preferred securities, options, forward contracts and swaps. Withdrawals from the fund prior to the first year anniversary of the investment are subject to a 5% withdrawal fee and withdrawals during any calendar quarter are limited to 25% of the fund's net asset value. Both of these restrictions can be waived by us, in our sole discretion.

Fair_Value_Disclosures_Investm1

Fair Value Disclosures (Investments Measured At Fair Value Based On Net Asset Value) (Additional Information) (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015		Dec. 31, 2014
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded commitments	25,764,000	[1]	26,117,000	[1]
Equity Long/Short Hedge Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Amount redeemable	78,000,000
Investment in private asset management fund managed by company	48,800,000		117,200,000
Funds Of Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Percentage of investments with no redemption provisions	96.00%		95.00%
Estimated period for the liquidation of the underlying assets	2 years		2 years
Folger Hill Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Notice period redemption of investments prior notice period	45 days
Investment in asset management funds	402,300,000
Number of funds	2
Multi-Strategy Fund [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fee to withdraw from fund	5.00%		5.00%
Quarterly maximum withdrawal percentage	25.00%		25.00%
Equity Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Percentage of investments in certain industries	99.00%		99.00%
Convertible Bond Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Notice period redemption of investments prior written notice period	5 days		5 days
Investments Which Are Not Investment Companies [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Investments at fair value	153,800,000		152,600,000
Minimum [Member] | Equity Long/Short Hedge Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Notice period redemption of investments prior written notice period	30 days		30 days
Minimum [Member] | Equity Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Estimated period for the liquidation of the underlying assets	1 year		1 year
Maximum [Member] | Equity Long/Short Hedge Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Notice period redemption of investments prior written notice period	90 days		90 days
Maximum [Member] | Equity Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Estimated period for the liquidation of the underlying assets	8 years		8 years
[1]	Investments at fair value in the Consolidated Statements of Financial Condition at March 31, 2015 and December 31, 2014, include $153.8 million and $152.6 million, respectively, of direct investments which do not have the characteristics of investment companies and therefore not included within this table.

Fair_Value_Disclosures_Summary

Fair Value Disclosures (Summary Of Trading Assets And Trading Liabilities) (Details)	Mar. 31, 2015	Dec. 31, 2014
Trading Assets and Trading Liabilities Measured Using Different Valuation Basis [Line Items]
Trading assets	100.00%	100.00%
Trading liabilities	100.00%	100.00%
Exchange Closing Prices [Member]
Trading Assets and Trading Liabilities Measured Using Different Valuation Basis [Line Items]
Trading assets	14.00%	16.00%
Trading liabilities	25.00%	20.00%
Recently Observed Transaction Prices [Member]
Trading Assets and Trading Liabilities Measured Using Different Valuation Basis [Line Items]
Trading assets	4.00%	4.00%
Trading liabilities	3.00%	2.00%
External Pricing Services [Member]
Trading Assets and Trading Liabilities Measured Using Different Valuation Basis [Line Items]
Trading assets	66.00%	67.00%
Trading liabilities	64.00%	69.00%
Broker Quotes [Member]
Trading Assets and Trading Liabilities Measured Using Different Valuation Basis [Line Items]
Trading assets	4.00%	4.00%
Trading liabilities	4.00%	3.00%
Valuation Techniques [Member]
Trading Assets and Trading Liabilities Measured Using Different Valuation Basis [Line Items]
Trading assets	12.00%	9.00%
Trading liabilities	4.00%	6.00%

Fair_Value_Disclosures_Summary1

Fair Value Disclosures (Summary Of Changes In Fair Value Of Financial Assets And Liabilities Classified As Level 3) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Total gains (losses) (realized and unrealized)	$638,600		$20,300
Total gains (losses) (realized and unrealized)	-6,900		-1,100
Corporate Equity Securities [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	20,964		9,884
Total gains (losses) (realized and unrealized)	63	[1]	-1,393	[1]
Purchases			134
Sales	-168
Net transfers into/ (out of) Level 3	-2,649		3,716
Ending Balance	18,210		12,341
Change in unrealized gains/(losses) relating to instruments still held	243	[1]	-1,319	[1]
Beginning Balance	38		38
Total gains (losses) (realized and unrealized)			8	[1]
Sales			411
Net transfers into/ (out of) Level 3			558
Ending Balance	38		1,015
Change in unrealized gains/(losses) relating to instruments still held			-8	[1]
Corporate Debt Securities [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	55,918		25,666
Total gains (losses) (realized and unrealized)	-1,930	[1]	-2,014	[1]
Purchases	469		4,136
Sales	-533		-624
Net transfers into/ (out of) Level 3	-23,189		2,151
Ending Balance	30,735		29,315
Change in unrealized gains/(losses) relating to instruments still held	-1,577	[1]	193	[1]
Beginning Balance	223
Total gains (losses) (realized and unrealized)	-115	[1]
Purchases	-6,683
Sales	6,698
Net transfers into/ (out of) Level 3	-123
Collateralized Debt Obligations [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	91,498		37,216
Total gains (losses) (realized and unrealized)	-16,022	[1]	10,184	[1]
Purchases			76,511
Sales	-13,519		-78,081
Settlements	-1,296		-144
Net transfers into/ (out of) Level 3	30,236		20,342
Ending Balance	90,897		66,028
Change in unrealized gains/(losses) relating to instruments still held	-15,886	[1]	5,662	[1]
Sovereign Obligations [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Total gains (losses) (realized and unrealized)	13	[1]
Sales	-1
Net transfers into/ (out of) Level 3	321
Ending Balance	333
Change in unrealized gains/(losses) relating to instruments still held	12	[1]
Residential Mortgage-Backed Securities [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	82,557		105,492
Total gains (losses) (realized and unrealized)	-2,863	[1]	-1,626	[1]
Purchases	2,100		9,637
Sales	-1,375		-13,703
Settlements	-23		-1,755
Net transfers into/ (out of) Level 3	-443		18,947
Ending Balance	79,953		116,992
Change in unrealized gains/(losses) relating to instruments still held	783	[1]	-2,097	[1]
Commercial Mortgage-Backed Securities [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	26,655		17,568
Total gains (losses) (realized and unrealized)	-531	[1]	-3,032	[1]
Purchases			8,933
Sales	-382		-14,645
Settlements	-6,864		-50
Net transfers into/ (out of) Level 3	5,751		8,712
Ending Balance	24,629		17,486
Change in unrealized gains/(losses) relating to instruments still held	-1,369	[1]	-958	[1]
Other Asset-Backed Securities [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	2,294		12,611
Total gains (losses) (realized and unrealized)	-167	[1]	72	[1]
Purchases	26		2,250
Sales	-1		-2,048
Settlements			-83
Net transfers into/ (out of) Level 3	4,994		-10,427
Ending Balance	7,146		2,375
Change in unrealized gains/(losses) relating to instruments still held	-167	[1]	7	[1]
Loans And Other Receivables [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	97,258		145,890
Total gains (losses) (realized and unrealized)	-5,033	[1]	-3,902	[1]
Purchases	40,019		36,213
Sales	-16,122		-49,475
Settlements	-15,448		-935
Net transfers into/ (out of) Level 3	10,736		1,041
Ending Balance	111,410		128,832
Change in unrealized gains/(losses) relating to instruments still held	-3,262	[1]	-3,807	[1]
Investments At Fair Value [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	119,212		101,242
Total gains (losses) (realized and unrealized)	609	[1]	24,889	[1]
Purchases	5,010		22,500
Sales	-594		-9,012
Settlements	-277
Net transfers into/ (out of) Level 3	69,134		-776
Ending Balance	193,094		138,843
Change in unrealized gains/(losses) relating to instruments still held	614	[1]	24,889	[1]
Investment in FXCM [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Total gains (losses) (realized and unrealized)	686,627	[1]
Purchases	279,000
Settlements	-18,627
Ending Balance	947,000
Change in unrealized gains/(losses) relating to instruments still held	686,627	[1]
Investments In Managed Funds [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	54,982		57,285
Total gains (losses) (realized and unrealized)	-22,211	[1]	-2,859	[1]
Purchases	400,354		5,102
Ending Balance	433,125		59,528
Change in unrealized gains/(losses) relating to instruments still held	-22,210	[1]	-2,859	[1]
Net Derivatives [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	-4,638	[2]	6,905	[2]
Total gains (losses) (realized and unrealized)	6,938	[1],[2]	1,267	[1],[2]
Purchases			-1,327	[2]
Sales			2,169	[2]
Settlements	-58	[2]	197	[2]
Issuances	1,072	[2]
Net transfers into/ (out of) Level 3			-3,438	[2]
Ending Balance	3,314	[2]	5,773	[2]
Change in unrealized gains/(losses) relating to instruments still held	-8,771	[1],[2]	-1,267	[1],[2]
Loans [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	14,450		22,462
Total gains (losses) (realized and unrealized)	-39	[1]	-153	[1]
Purchases	-2,877		-18,913
Sales	825		4,887
Net transfers into/ (out of) Level 3	-3,032		1,977
Ending Balance	9,327		10,260
Change in unrealized gains/(losses) relating to instruments still held	39	[1]	-153	[1]
Other Secured Financings [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	30,825		8,711
Settlements	-2,218
Issuances	36,995		21,683
Ending Balance	$65,602		$30,394
[1]	Realized and unrealized gains (losses) are reported in Principal transactions in the Consolidated Statements of Operations, except for realized and unrealized gains (losses) on Investments in managed funds, which are included in Other revenues in the Consolidated Statements of Operations.
[2]	Net derivatives represent Trading assets - Derivatives and Trading liabilities - Derivatives.

Fair_Value_Disclosures_Quantit

Fair Value Disclosures (Quantitative Information About Significant Unobservable Inputs Used In Level 3 Fair Value Measurements) (Details) (USD $)	3 Months Ended	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value of Financial Instruments Owned, Derivatives and Other Contractual Agreements	$497,092	$406,268
Derivatives, Liabilities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value of Trading Liabilities	49,450	49,552
Fair Value Inputs, Constant prepayment rate	20.00%
Fair Value Inputs, Constant default rate	2.00%
Fair Value Inputs, Loss severity	25.00%
Fair Value Inputs, Credit Spread		45.00%
Fair Value Inputs, Yield	11.00%	5.00%
Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value of Trading Liabilities	9,327	14,450
Fair Value Inputs, Comparable loan price	$100	$100
Other Secured Financings [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value of Trading Liabilities	65,602	30,825
Minimum [Member] | Derivatives, Liabilities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Volatility	12.00%	13.00%
Fair Value Inputs, Comparable loan price	$71	$89
Fair Value Inputs, Yield	5.00%
Minimum [Member] | Other Secured Financings [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Comparable loan price	$82	$81
Maximum [Member] | Derivatives, Liabilities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Volatility	23.00%	23.00%
Fair Value Inputs, Comparable loan price	$100	$100
Fair Value Inputs, Yield	8.00%
Maximum [Member] | Other Secured Financings [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Comparable loan price	$100	$100
Weighted Average [Member] | Derivatives, Liabilities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Volatility	15.00%	17.00%
Fair Value Inputs, Comparable loan price	$78.60	$92
Fair Value Inputs, Yield	8.00%
Weighted Average [Member] | Other Secured Financings [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Comparable loan price	$98.90	$98.70
Corporate Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value of Financial Instruments Owned	18,210	19,814
Fair Value Inputs, Estimated Recovery Percentage	78.00%	24.00%
Corporate Equity Securities [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple	3.5	3.4
Corporate Equity Securities [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple	8.6	4.7
Corporate Equity Securities [Member] | Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple	4.4	3.6
Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value of Financial Instruments Owned	24,795	22,766
Fair Value Inputs, Discount rate/yield	32.00%	32.00%
Collateralized Debt Obligations [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value of Financial Instruments Owned	51,095	41,784
Collateralized Debt Obligations [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Constant prepayment rate	0.00%	0.00%
Fair Value Inputs, Constant default rate	0.00%	0.00%
Fair Value Inputs, Loss severity	0.00%	0.00%
Fair Value Inputs, Yield	6.00%	2.00%
Collateralized Debt Obligations [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Constant prepayment rate	20.00%	20.00%
Fair Value Inputs, Constant default rate	2.00%	2.00%
Fair Value Inputs, Loss severity	70.00%	70.00%
Fair Value Inputs, Yield	20.00%	51.00%
Collateralized Debt Obligations [Member] | Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Constant prepayment rate	14.00%	13.00%
Fair Value Inputs, Constant default rate	2.00%	2.00%
Fair Value Inputs, Loss severity	42.00%	39.00%
Fair Value Inputs, Yield	13.00%	16.00%
Residential Mortgage-Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value of Financial Instruments Owned	79,953	82,557
Residential Mortgage-Backed Securities [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Constant prepayment rate	2.00%	1.00%
Fair Value Inputs, Constant default rate	2.00%	1.00%
Fair Value Inputs, Loss severity	35.00%	20.00%
Fair Value Inputs, Yield	1.00%	3.00%
Residential Mortgage-Backed Securities [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Constant prepayment rate	50.00%	50.00%
Fair Value Inputs, Constant default rate	100.00%	100.00%
Fair Value Inputs, Loss severity	80.00%	80.00%
Fair Value Inputs, Yield	13.00%	13.00%
Residential Mortgage-Backed Securities [Member] | Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Constant prepayment rate	13.00%	13.00%
Fair Value Inputs, Constant default rate	21.00%	14.00%
Fair Value Inputs, Loss severity	52.00%	50.00%
Fair Value Inputs, Yield	6.00%	7.00%
Commercial Mortgage-Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value of Financial Instruments Owned	24,629	26,655
Fair Value Inputs, Estimated Recovery Percentage	81.00%	90.00%
Commercial Mortgage-Backed Securities [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Yield	8.00%	8.00%
Fair Value Inputs, Cumulative loss rate	1.90%	4.00%
Commercial Mortgage-Backed Securities [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Yield	22.00%	12.00%
Fair Value Inputs, Cumulative loss rate	73.00%	72.00%
Commercial Mortgage-Backed Securities [Member] | Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Yield	14.00%	11.00%
Fair Value Inputs, Cumulative loss rate	16.00%	15.00%
Other Asset-Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value of Financial Instruments Owned	7,146	2,294
Fair Value Inputs, Constant prepayment rate		8.00%
Fair Value Inputs, Constant default rate		3.00%
Fair Value Inputs, Loss severity		70.00%
Fair Value Inputs, Yield		7.00%
Other Asset-Backed Securities [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Constant prepayment rate	4.00%
Fair Value Inputs, Constant default rate	3.00%
Fair Value Inputs, Loss severity	50.00%
Fair Value Inputs, Yield	6.00%
Other Asset-Backed Securities [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Constant prepayment rate	6.00%
Fair Value Inputs, Constant default rate	4.00%
Fair Value Inputs, Loss severity	60.00%
Fair Value Inputs, Yield	7.00%
Other Asset-Backed Securities [Member] | Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Constant prepayment rate	4.00%
Fair Value Inputs, Constant default rate	4.00%
Fair Value Inputs, Loss severity	52.00%
Fair Value Inputs, Yield	6.00%
Loans And Other Receivables [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value of Financial Instruments Owned	102,034	88,154
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple	8.2
Fair Value Inputs, Constant prepayment rate	20.00%
Fair Value Inputs, Constant default rate	2.00%
Fair Value Inputs, Loss severity	25.00%
Fair Value Inputs, Yield	11.00%
Loans And Other Receivables [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple		3.4
Fair Value Inputs, Estimated Recovery Percentage	10.00%	10.00%
Fair Value Inputs, Comparable loan price	$100	$100
Fair Value Inputs, Yield	3.00%	3.00%
Loans And Other Receivables [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple		8.2
Fair Value Inputs, Estimated Recovery Percentage	81.00%	41.00%
Fair Value Inputs, Comparable loan price	$101	$101
Fair Value Inputs, Yield	9.00%	5.00%
Loans And Other Receivables [Member] | Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple		7.6
Fair Value Inputs, Estimated Recovery Percentage	37.00%	36.00%
Fair Value Inputs, Comparable loan price	$100.50	$100.30
Fair Value Inputs, Yield	7.00%	4.00%
Derivatives, Assets [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value of Financial Instruments Owned	46,136	54,190
Fair Value Inputs, Comparable loan price		$100
Fair Value Inputs, Yield	8.00%
Fair Value Inputs, Discount rate	20.00%	17.00%
Derivatives, Assets [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Volatility	12.00%	13.00%
Fair Value Inputs, Comparable loan price	$71
Derivatives, Assets [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Volatility	23.00%	23.00%
Fair Value Inputs, Comparable loan price	$100
Derivatives, Assets [Member] | Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Volatility	15.00%	17.00%
Fair Value Inputs, Comparable loan price	$99
Investments At Fair Value [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value of Financial Instruments Owned	32,312	32,323
Fair Value Inputs, Transaction Level	$57	$50
Investments At Fair Value [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Discount rate	15.00%	15.00%
Investments At Fair Value [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Discount rate	30.00%	30.00%
Investments At Fair Value [Member] | Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Discount rate	23.00%	23.00%
Investment in FXCM [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value of Financial Instruments Owned	947,000
Fair Value of Senior Secured Term Loan Receivable	310,000
Fair Value of Financial Instruments Owned, Derivatives and Other Contractual Agreements	$637,000
Fair Value Inputs, Volatility	65.00%
Investment in FXCM [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Term based on the pay off	6 months
Investment in FXCM [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Term based on the pay off	1 year 9 months 18 days
Investment in FXCM [Member] | Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Term based on the pay off	9 months 18 days

Fair_Value_Disclosures_Summary2

Fair Value Disclosures (Summary Of Gains (Losses) Due To Changes In Instrument Specific Credit Risk For Loans and Other Receivables And Loan Commitments Measured At Fair Value Under Fair Value Option) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Financial Instruments [Line Items]
Loans and other receivables	$5,389	$4,467
Financial Instruments Sold [Member]
Financial Instruments [Line Items]
Loans	-1,022	-462
Loan Commitments	($7,166)	($2,357)

Fair_Value_Disclosures_Summary3

Fair Value Disclosures (Summary Of Amount By Which Contractual Principal Exceeds Fair Value For Loans And Other Receivables Measured At Fair Value Under Fair Value Option) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
Fair Value Disclosures [Abstract]
Loans and other receivables	$426,425,000	[1]	$403,119,000	[1]
Loans and other receivables greater than 90 days past due	28,829,000	[1]	5,594,000	[1]
Loans and other receivables on nonaccrual status	-36,471,000	[1],[2]	-22,360,000	[1],[2]
Aggregate fair value of loans 90 or more days past due	14,100,000		0
Aggregate fair value of loans and other receivables on nonaccrual status	$285,700,000		$274,600,000
[1]	Interest income is recognized separately from other changes in fair value and is included within Interest income in the Consolidated Statements of Operations.
[2]	Amounts include all loans and other receivables greater than 90 days past due.

Derivative_Financial_Instrumen2

Derivative Financial Instruments (Narrative) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Derivative Financial Instruments [Abstract]
Fair value of derivative instruments in a liability position	$298.60	$269
Collateral posted for derivative instruments in a liability position	279	234.6
Potential additional collateral required for derivative instruments in a liability position	$36.50	$55.10

Derivative_Financial_Instrumen3

Derivative Financial Instruments (Fair Value And Related Number Of Derivative Contracts Categorized By Predominant Risk Exposure) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Derivatives, Fair Value [Line Items]
Fair Value, Assets	$5,226,625	$5,165,613
Fair Value, Liabilities	5,133,092	5,220,133
Counterparty/cash-collateral netting, Assets	-4,729,533	-4,759,345
Counterparty/cash-collateral netting, Liabilities	-4,810,751	-4,856,618
Total Derivative Assets per Consolidated Statement of Financial Condition	497,092	406,268
Total Derivative Liabilities per Consolidated Statement of Financial Condition	322,341	363,515
Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	2,688,316	2,299,807
Number of Contracts, Assets	78,835	71,505
Fair Value, Liabilities	2,633,960	2,292,691
Number of Contracts, Liabilities	124,133	89,861
Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	1,366,539	1,514,881
Number of Contracts, Assets	14,138	12,861
Fair Value, Liabilities	1,327,400	1,519,349
Number of Contracts, Liabilities	12,867	12,752
Equity Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	836,053	1,050,990
Number of Contracts, Assets	1,909,862	2,271,507
Fair Value, Liabilities	838,598	1,058,015
Number of Contracts, Liabilities	1,889,424	2,051,469
Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	245,818	276,726
Number of Contracts, Assets	941,231	1,031,568
Fair Value, Liabilities	215,191	303,206
Number of Contracts, Liabilities	948,122	1,020,418
Credit Contracts: Centrally Cleared Swaps [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	79,540	17,831
Number of Contracts, Assets	102	27
Fair Value, Liabilities	84,075	23,264
Number of Contracts, Liabilities	88	22
Credit Contracts: Other Credit Derivatives [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	10,359	5,378
Number of Contracts, Assets	38	18
Fair Value, Liabilities	$33,868	$23,608
Number of Contracts, Liabilities	42	27

Derivative_Financial_Instrumen4

Derivative Financial Instruments (Unrealized And Realized Gains (Losses) On Derivative Contracts (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	$51,869	($82,979)
Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	-42,793	-5,118
Foreign Exchange Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	15,172	6,067
Equity Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	71,041	-96,236
Commodity Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	14,491	16,186
Credit Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses)	($6,042)	($3,878)

Derivative_Financial_Instrumen5

Derivative Financial Instruments (Remaining Contract Maturity Of Fair Value Of OTC Derivative Assets And Liabilities) (Details) (USD $)	Mar. 31, 2015
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	$498,759,000	[1],[2],[3]
OTC derivative assets having maturity period of 1 to 5 years	262,124,000	[1],[2],[3]
OTC derivative assets having maturity period of greater than 5 years	162,386,000	[1],[2],[3]
OTC derivative assets cross-maturity netting	-95,513,000	[1],[2],[3],[4]
Total OTC derivative assets, net of cross-maturity netting	827,756,000	[1],[2],[3]
Cross product counterparty netting	-21,605,000	[1],[2],[3]
Total OTC derivative assets included in Trading assets	806,151,000	[1],[2],[3],[5]
OTC derivative liabilities having maturity period of 0 to 12 months	466,310,000	[3],[6],[7]
OTC derivative liabilities having maturity period of 1 to 5 years	233,323,000	[3],[6],[7]
OTC derivative liabilities having maturity period of greater than 5 years	170,215,000	[3],[6],[7]
OTC derivative liabilities cross-maturity netting	-95,513,000	[3],[4],[6],[7]
Total OTC derivative liabilities, net of cross-maturity netting	774,335,000	[3],[6],[7]
Cross product counterparty netting	-21,605,000	[3],[6],[7]
Total OTC derivative liabilities included in Trading liabilities	752,730,000	[3],[6],[7]
Exchange traded derivative assets and other credit agreements	67,900,000
Cash collateral received	377,000,000
Exchange traded derivative liabilities and other credit agreements	28,000,000
Cash collateral pledged	458,400,000
Commodity Swaps, Options And Forwards [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	57,079,000	[1],[2],[3]
OTC derivative assets having maturity period of 1 to 5 years	2,674,000	[1],[2],[3]
OTC derivative assets having maturity period of greater than 5 years	23,599,000	[1],[2],[3]
OTC derivative assets cross-maturity netting	-2,915,000	[1],[2],[3],[4]
Total OTC derivative assets, net of cross-maturity netting	80,437,000	[1],[2],[3]
OTC derivative liabilities having maturity period of 0 to 12 months	68,406,000	[3],[6],[7]
OTC derivative liabilities having maturity period of 1 to 5 years	254,000	[3],[6],[7]
OTC derivative liabilities having maturity period of greater than 5 years	5,377,000	[3],[6],[7]
OTC derivative liabilities cross-maturity netting	-2,915,000	[3],[4],[6],[7]
Total OTC derivative liabilities, net of cross-maturity netting	71,122,000	[3],[6],[7]
Credit Default Swaps [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of greater than 5 years	7,442,000	[1],[2],[3]
OTC derivative assets cross-maturity netting	-254,000	[1],[2],[3],[4]
Total OTC derivative assets, net of cross-maturity netting	7,188,000	[1],[2],[3]
OTC derivative liabilities having maturity period of 0 to 12 months	254,000	[3],[6],[7]
OTC derivative liabilities having maturity period of 1 to 5 years	6,242,000	[3],[6],[7]
OTC derivative liabilities having maturity period of greater than 5 years	2,103,000	[3],[6],[7]
OTC derivative liabilities cross-maturity netting	-254,000	[3],[4],[6],[7]
Total OTC derivative liabilities, net of cross-maturity netting	8,345,000	[3],[6],[7]
Equity Swaps And Options [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	8,894,000	[1],[2],[3]
OTC derivative assets having maturity period of 1 to 5 years	31,585,000	[1],[2],[3]
OTC derivative assets having maturity period of greater than 5 years	5,657,000	[1],[2],[3]
Total OTC derivative assets, net of cross-maturity netting	46,136,000	[1],[2],[3]
OTC derivative liabilities having maturity period of 0 to 12 months	4,670,000	[3],[6],[7]
OTC derivative liabilities having maturity period of 1 to 5 years	59,118,000	[3],[6],[7]
OTC derivative liabilities having maturity period of greater than 5 years	19,452,000	[3],[6],[7]
Total OTC derivative liabilities, net of cross-maturity netting	83,240,000	[3],[6],[7]
Total Return Swaps [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	10,135,000	[1],[2],[3]
OTC derivative assets having maturity period of 1 to 5 years	377,000	[1],[2],[3]
OTC derivative assets cross-maturity netting	-299,000	[1],[2],[3],[4]
Total OTC derivative assets, net of cross-maturity netting	10,213,000	[1],[2],[3]
OTC derivative liabilities having maturity period of 0 to 12 months	15,733,000	[3],[6],[7]
OTC derivative liabilities having maturity period of 1 to 5 years	1,412,000	[3],[6],[7]
OTC derivative liabilities cross-maturity netting	-299,000	[3],[4],[6],[7]
Total OTC derivative liabilities, net of cross-maturity netting	16,846,000	[3],[6],[7]
Foreign Currency Forwards, Swaps And Options [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	376,842,000	[1],[2],[3]
OTC derivative assets having maturity period of 1 to 5 years	48,591,000	[1],[2],[3]
OTC derivative assets having maturity period of greater than 5 years	90,000	[1],[2],[3]
OTC derivative assets cross-maturity netting	-23,179,000	[1],[2],[3],[4]
Total OTC derivative assets, net of cross-maturity netting	402,344,000	[1],[2],[3]
OTC derivative liabilities having maturity period of 0 to 12 months	326,435,000	[3],[6],[7]
OTC derivative liabilities having maturity period of 1 to 5 years	60,213,000	[3],[6],[7]
OTC derivative liabilities cross-maturity netting	-23,179,000	[3],[4],[6],[7]
Total OTC derivative liabilities, net of cross-maturity netting	363,469,000	[3],[6],[7]
Fixed Income Forwards [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative liabilities having maturity period of 0 to 12 months	431,000	[3],[6],[7]
Total OTC derivative liabilities, net of cross-maturity netting	431,000	[3],[6],[7]
Interest Rate Swaps, Options And Forwards [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	45,809,000	[1],[2],[3]
OTC derivative assets having maturity period of 1 to 5 years	178,897,000	[1],[2],[3]
OTC derivative assets having maturity period of greater than 5 years	125,598,000	[1],[2],[3]
OTC derivative assets cross-maturity netting	-68,866,000	[1],[2],[3],[4]
Total OTC derivative assets, net of cross-maturity netting	281,438,000	[1],[2],[3]
OTC derivative liabilities having maturity period of 0 to 12 months	50,381,000	[3],[6],[7]
OTC derivative liabilities having maturity period of 1 to 5 years	106,084,000	[3],[6],[7]
OTC derivative liabilities having maturity period of greater than 5 years	143,283,000	[3],[6],[7]
OTC derivative liabilities cross-maturity netting	-68,866,000	[3],[4],[6],[7]
Total OTC derivative liabilities, net of cross-maturity netting	$230,882,000	[3],[6],[7]
[1]	At March 31, 2015, we held exchange traded derivative assets and other credit agreements with a fair value of $67.9 million, which are not included in this table.
[2]	OTC derivative assets in the table above are gross of collateral received. OTC derivative assets are recorded net of collateral received in the Consolidated Statements of Financial Condition. At March 31, 2015 cash collateral received was $377.0 million.
[3]	Derivative fair values include counterparty netting within product category.
[4]	Amounts represent the netting of receivable balances with payable balances for the same counterparty within product category across maturity categories.
[5]	We utilize internal credit ratings determined by Jefferies Risk Management. Credit ratings determined by Risk Management use methodologies that produce ratings generally consistent with those produced by external rating agencies.
[6]	At March 31, 2015, we held exchange traded derivative liabilities and other credit agreements with a fair value of $28.0 million, which are not included in this table.
[7]	OTC derivative liabilities in the table above are gross of collateral pledged. OTC derivative liabilities are recorded net of collateral pledged in the Consolidated Statements of Financial Condition. At March 31, 2015, cash collateral pledged was $458.4 million.

Derivative_Financial_Instrumen6

Derivative Financial Instruments (Counterparty Credit Quality With Respect To Fair Value Of OTC Derivatives Assets) (Details) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Derivative Financial Instruments [Abstract]
Fair value of OTC derivatives assets, Counterparty credit quality, A- or higher	$508,060	[1]
Fair value of OTC derivatives assets, Counterparty credit quality, BBB- to BBB+	107,645	[1]
Fair value of OTC derivatives assets, Counterparty credit quality, BB+ or lower	94,772	[1]
Fair value of OTC derivatives assets, Counterparty credit quality, Unrated	95,674	[1]
Fair value of Over the Counter Derivatives Assets Counterparty credit quality	$806,151	[1],[2],[3],[4]
[1]	We utilize internal credit ratings determined by Jefferies Risk Management. Credit ratings determined by Risk Management use methodologies that produce ratings generally consistent with those produced by external rating agencies.
[2]	At March 31, 2015, we held exchange traded derivative assets and other credit agreements with a fair value of $67.9 million, which are not included in this table.
[3]	OTC derivative assets in the table above are gross of collateral received. OTC derivative assets are recorded net of collateral received in the Consolidated Statements of Financial Condition. At March 31, 2015 cash collateral received was $377.0 million.
[4]	Derivative fair values include counterparty netting within product category.

Collateralized_Transactions_De

Collateralized Transactions (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Collateralized Transactions [Abstract]
Fair value of securities received as collateral that may be sold or repledged	$23,100,000,000	$25,800,000,000
Obligation to return securities received as collateral	4,821,000	5,418,000
Securities received as collateral	$4,821,000	$5,418,000

Securitization_Activities_Acti

Securitization Activities (Activity Related To Securitizations Accounted For As Sales) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Securitization Activities [Abstract]
Transferred assets	$1,562.90	$1,626.90
Proceeds on new securitizations	1,564.50	1,628.10
Cash flows received on retained interests	$2.40	$8.50

Securitization_Activities_Summ

Securitization Activities (Summary Of Retained Interests In SPEs) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Securitization Activities [Line Items]
U.S. Government agency residential mortgage-backed Securities	$11,742.90	$19,196.90
U.S. Government agency commercial mortgage-backed Securities	3,519.50	5,848.50
Collateralized loan obligations	4,169.90	4,511.80
Residential Mortgage-Backed Securities [Member]
Securitization Activities [Line Items]
Retained Interests	403.7	226.9
Commercial Mortgage-Backed Securities [Member]
Securitization Activities [Line Items]
Retained Interests	97.9	204.7
Collateralized Loan Obligations Securitizations [Member]
Securitization Activities [Line Items]
Retained Interests	$53.30	$108.40

Available_For_Sale_Securities_1

Available For Sale Securities (Amortized Cost, Gross Unrealized Gains And Losses And Estimated Fair Value Of Available For Sale Investments) (Details) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Schedule of Investments [Line Items]
Amortized Cost	$935,099	$1,562,456
Gross Unrealized Gains	40,198	49,300
Gross Unrealized Losses	867	2,987
Estimated Fair Value	974,430	1,608,769
U.S. Government Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	213,621	593,803
Gross Unrealized Gains	3	33
Gross Unrealized Losses	13	63
Estimated Fair Value	213,611	593,773
Residential Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	490,171	597,402
Gross Unrealized Gains	9,156	10,959
Gross Unrealized Losses	451	1,678
Estimated Fair Value	498,876	606,683
Commercial Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	27,534	42,991
Gross Unrealized Gains	400	484
Gross Unrealized Losses	20	74
Estimated Fair Value	27,914	43,401
Other Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	130,584	245,533
Gross Unrealized Gains	286	619
Gross Unrealized Losses	362	996
Estimated Fair Value	130,508	245,156
All Other Corporates [Member]
Schedule of Investments [Line Items]
Amortized Cost	29,410	30,519
Gross Unrealized Gains	139	60
Gross Unrealized Losses	21	176
Estimated Fair Value	29,528	30,403
Debt Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	891,320	1,510,248
Gross Unrealized Gains	9,984	12,155
Gross Unrealized Losses	867	2,987
Estimated Fair Value	900,437	1,519,416
Common Stocks: Banks, Trusts And Insurance Companies [Member]
Schedule of Investments [Line Items]
Amortized Cost	24,687	31,853
Gross Unrealized Gains	14,696	18,740
Estimated Fair Value	39,383	50,593
Common Stocks: Industrial, Miscellaneous And All Other [Member]
Schedule of Investments [Line Items]
Amortized Cost	19,092	20,355
Gross Unrealized Gains	15,518	18,405
Estimated Fair Value	34,610	38,760
Corporate Equity Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	43,779	52,208
Gross Unrealized Gains	30,214	37,145
Estimated Fair Value	$73,993	$89,353

Available_For_Sale_Securities_2

Available For Sale Securities (Amortized Cost And Estimated Fair Value Of Investments Classified As Available For Sale By Contractual Maturity) (Details) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Available For Sale Securities [Abstract]
Due within one year, Amortized Cost	$228,255
Due after one year through five years, Amortized Cost	14,776
Fixed maturities investments excluding mortgage-backed and asset-backed securities, Amortized Cost	243,031
Mortgage-backed and asset-backed securities, Amortized Cost	648,289
Total fixed maturities investments, Amortized Cost	891,320
Due within one year, Estimated Fair Value	228,292
Due after one year through five years, Estimated Fair Value	14,847
Fixed maturities investments excluding mortgage-backed and asset-backed securities, Estimated Fair Value	243,139
Mortgage-backed and asset-backed securities, Estimated Fair Value	657,298
Total fixed maturities investments, Estimated Fair Value	$900,437

Variable_Interest_Entities_Nar

Variable Interest Entities (Narrative) (Details) (USD $)	3 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Variable Interest Entity [Line Items]
Carrying Amount	$280.40	[1]	$360.20	[1]
Maximum exposure to loss	1,631		1,795.20
SBI USA Fund [Member]
Variable Interest Entity [Line Items]
Commitment funded	60.4		60.1
Carrying amount of equity investment	22.7		43.1
Maximum amount committed to invest as per agreement	75		75
JEP IV [Member]
Variable Interest Entity [Line Items]
Carrying amount of equity investment	1		1.2
Energy Partners I, LP [Member]
Variable Interest Entity [Line Items]
Carrying Amount	0
Maximum exposure to loss	10
Agency Mortgage-Backed Securitizations [Member]
Variable Interest Entity [Line Items]
Carrying Amount	2,729.50		3,186.90
Nonagency Mortgage- And Asset-Backed Securitizations [Member]
Variable Interest Entity [Line Items]
Carrying Amount	$930.10		$1,120
[1]	There were no significant liabilities at March 31, 2015 and December 31, 2014.

Variable_Interest_Entities_Ass

Variable Interest Entities (Assets And Liabilities Of Consolidated VIEs) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
Variable Interest Entity [Line Items]
Cash	$3,524,524,000		$4,276,775,000
Financial instruments owned	21,945,517,000		21,221,259,000
Securities purchased under agreement to resell	3,745,688,000		3,926,858,000
Other	1,707,033,000		1,807,284,000
Total	52,322,692,000		52,623,908,000
Other secured financings	950,377,000		705,126,000
Total liabilities	41,308,780,000		41,942,200,000
Securitization Vehicles [Member]
Variable Interest Entity [Line Items]
Cash	400,000		500,000
Financial instruments owned	65,600,000		62,700,000
Securities purchased under agreement to resell	795,400,000	[1]	575,200,000	[1]
Other	97,200,000		107,100,000
Total	958,600,000		745,500,000
Other secured financings	950,400,000	[2]	737,000,000	[2]
Other	8,200,000		8,500,000
Total liabilities	958,600,000		745,500,000
Jefferies [Member]
Variable Interest Entity [Line Items]
Secured financings eliminated in consolidation	$5,600,000		$39,700,000
[1]	Securities purchased under agreement to resell represent an amount due under a collateralized transaction on a related consolidated entity, which is eliminated in consolidation.
[2]	Approximately $5.6 million and $39.7 million of the secured financing represents an amount held by Jefferies in inventory and eliminated in consolidation at March 31, 2015 and December 31, 2014, respectively.

Variable_Interest_Entities_Non

Variable Interest Entities (Non-Consolidated Variable Interest Entities) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Millions, unless otherwise specified
Variable Interest Entity [Line Items]
Total Financial Statement Carrying Amount, Assets	$280.40	[1]	$360.20	[1]
Total Maximum exposure to loss in non-consolidated VIEs	1,631		1,795.20
Total VIE Assets	8,807.20		8,747.40
Collateralized Loan Obligations [Member]
Variable Interest Entity [Line Items]
Total Financial Statement Carrying Amount, Assets	75.4	[1]	134	[1]
Total Maximum exposure to loss in non-consolidated VIEs	817.9		926.9
Total VIE Assets	8,125.20		7,737.10
Consumer Loan Financing Vehicles [Member]
Variable Interest Entity [Line Items]
Total Financial Statement Carrying Amount, Assets	175.3	[1]	170.6	[1]
Total Maximum exposure to loss in non-consolidated VIEs	758.8		797.8
Total VIE Assets	411.6		485.2
Asset Management Vehicles [Member]
Variable Interest Entity [Line Items]
Total Financial Statement Carrying Amount, Assets	6	[1],[2]	11.3	[1],[2]
Total Maximum exposure to loss in non-consolidated VIEs	6	[2]	11.3	[2]
Total VIE Assets	199.6	[2]	432.3	[2]
Private Equity Vehicles [Member]
Variable Interest Entity [Line Items]
Total Financial Statement Carrying Amount, Assets	23.7	[1],[3]	44.3	[1],[3]
Total Maximum exposure to loss in non-consolidated VIEs	48.3	[3]	59.2	[3]
Total VIE Assets	$70.80	[3]	$92.80	[3]
[1]	There were no significant liabilities at March 31, 2015 and December 31, 2014.
[2]	Assets consist of equity interests, which are included within Investments in managed funds, and accrued management and performance fees, which are included in Receivables.
[3]	Assets consist of equity interests, which are included in Investment in managed funds.

Loans_To_And_Investments_In_As2

Loans To And Investments In Associated Companies (Jefferies Finance) (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Investments In Associated Companies [Line Items]
Investment banking	$250,995,000	$414,320,000
Receivables	4,354,707,000		3,934,825,000
Jefferies Finance [Member]
Investments In Associated Companies [Line Items]
Equity commitment	600,000,000
Total line of credit facility commitment under joint venture	1,000,000,000
Committed line of credit facility amount	700,000,000
Discretionary line of credit facility amount	300,000,000
Funded portion of line of credit commitment	0		0
Line of credit facility commitment of Jefferies	350,000,000		350,000,000
Funded Equity Commitments	506,700,000
Investment commitment extension	1 year
Termination notice	60 days
Receivables	15,500,000		41,500,000
Service fees	27,800,000	21,700,000
Jefferies [Member]
Investments In Associated Companies [Line Items]
Investment banking	15,600,000	47,600,000
Service fee income	400,000
Origination fees	$700,000	$4,300,000

Loans_To_And_Investments_In_As3

Loans To And Investments In Associated Companies (Jefferies LoanCore) (Narrative) (Details) (Jefferies LoanCore [Member], USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Jefferies LoanCore [Member]
Investments In Associated Companies [Line Items]
Aggregate equity commitment	$600	$600
Equity commitment	291	291
Funded Equity Commitments	$237	$200.90
Percentage of voting interest	48.50%	48.50%

Loans_To_And_Investments_In_As4

Loans To And Investments In Associated Companies (Berkadia) (Narrative) (Details) (Berkadia [Member], USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2009
Investments In Associated Companies [Line Items]
Percentage of ownership owned	50.00%
Capital contributed		$217,200,000
Surety policy issued	2,500,000,000
Reimbursement of losses incurred, maximum percentage	50.00%
Commercial paper	2,470,000,000
Inception To Date [Member]
Investments In Associated Companies [Line Items]
Distributions received	$322,500,000

Loans_To_And_Investments_In_As5

Loans To And Investments In Associated Companies (Linkem) (Narrative) (Details) (Linkem [Member])	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2015
	USD ($)	EUR (€)
Investments In Associated Companies [Line Items]
Percentage of ownership owned	42.00%
Cash consideration	$142.90
Interest rate on convertible notes	5.00%
Payments to acquire convertible notes	101
Convertible notes principal amount		€ 78.90
Percentage of ownership upon conversion of note	55.00%
Excess investment amortization period, years	12 years

Loans_To_And_Investments_In_As6

Loans To And Investments In Associated Companies (HomeFed) (Narrative) (Details) (HomeFed Corporation [Member], USD $)	3 Months Ended	12 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Investments In Associated Companies [Line Items]
Shares of common stock owned	9,974,226
Percentage of ownership owned	65.00%
Cash paid on acquisition of common shares		$14
Common shares acquired		7,500,000
Maximum voting rights as a percentage of total voting securities voting	45.00%
Deferred gain on sale		$36.10
Company Chairman [Member]
Investments In Associated Companies [Line Items]
Ownership percentage of company	4.80%

Loans_To_And_Investments_In_As7

Loans To And Investments In Associated Companies (Golden Queen Mining Company) (Narrative) (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Investments In Associated Companies [Line Items]
Contributions from noncontrolling interests	$533,000	$8,604,000
Gauss LLC [Member]
Investments In Associated Companies [Line Items]
Cash invested in Limited Liability Company			70,900,000
Clay Family [Member]
Investments In Associated Companies [Line Items]
Contributions from noncontrolling interests			34,100,000
Golden Queen Mining Company, LLC [Member]
Investments In Associated Companies [Line Items]
Percentage of ownership owned	34.00%
Potential additional investment amount	27,000,000
Golden Queen Mining Company, LLC [Member] | Gauss LLC [Member]
Investments In Associated Companies [Line Items]
Total investment in associated company	$105,000,000
Percentage of ownership owned	50.00%
Golden Queen Mining Co, Ltd [Member]
Investments In Associated Companies [Line Items]
Ownership percentage	50.00%

Loans_To_And_Investments_In_As8

Loans To And Investments In Associated Companies (Schedule Of Investments In Associated Companies) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
Investments In Associated Companies [Line Items]
Equity method investments	$1,762,711		$1,712,568
Noncontrolling interests	68,533		67,864
Jefferies Finance [Member]
Investments In Associated Companies [Line Items]
Equity method investments	520,203		508,891
Jefferies LoanCore [Member]
Investments In Associated Companies [Line Items]
Equity method investments	301,549		258,947
Berkadia [Member]
Investments In Associated Companies [Line Items]
Equity method investments	219,017		208,511
Garcadia [Member]
Investments In Associated Companies [Line Items]
Equity method investments	170,876		167,939
HomeFed Corporation [Member]
Investments In Associated Companies [Line Items]
Equity method investments	269,684		271,782
Linkem [Member]
Investments In Associated Companies [Line Items]
Equity method investments	144,813		159,054
Golden Queen Mining Company, LLC [Member]
Investments In Associated Companies [Line Items]
Equity method investments	103,311	[1]	103,598	[1]
Noncontrolling interests	33,600		33,700
Other [Member]
Investments In Associated Companies [Line Items]
Equity method investments	$33,258		$33,846
[1]	At March 31, 2015 and December 31, 2014, the balance reflects $33.6 million and $33.7 million, respectively, related to a noncontrolling interest.

Loans_To_And_Investments_In_As9

Loans To And Investments In Associated Companies (Schedule Of Income (Losses) Related To Associated Companies) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Investments In Associated Companies [Line Items]
Income (losses) related to associated companies before income taxes	$40,451	$20,036
Berkadia [Member]
Investments In Associated Companies [Line Items]
Income (losses) related to associated companies before income taxes	32,343	13,973
Garcadia [Member]
Investments In Associated Companies [Line Items]
Income (losses) related to associated companies before income taxes	15,253	11,259
HomeFed Corporation [Member]
Investments In Associated Companies [Line Items]
Income (losses) related to associated companies before income taxes	-2,098	-618
Linkem [Member]
Investments In Associated Companies [Line Items]
Income (losses) related to associated companies before income taxes	-4,788	-5,836
Golden Queen Mining Company, LLC [Member]
Investments In Associated Companies [Line Items]
Income (losses) related to associated companies before income taxes	-287
Other [Member]
Investments In Associated Companies [Line Items]
Income (losses) related to associated companies before income taxes	$28	$1,258

Recovered_Sheet2

Loans To And Investments In Associated Companies (Schedule Of Income (Losses) Related To Associated Companies Classified As Other Revenue) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Investments In Associated Companies [Line Items]
Income (losses) related to associated companies classified as Other revenue	$20,689	$20,627
Jefferies Finance [Member]
Investments In Associated Companies [Line Items]
Income (losses) related to associated companies classified as Other revenue	11,311	17,601
Jefferies LoanCore [Member]
Investments In Associated Companies [Line Items]
Income (losses) related to associated companies classified as Other revenue	9,858	2,482
Other [Member]
Investments In Associated Companies [Line Items]
Income (losses) related to associated companies classified as Other revenue	($480)	$544

Financial_Statement_Offsetting2

Financial Statement Offsetting (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
Financial Statement Offsetting [Abstract]
Derivative contracts, Gross Amounts	$5,226,625,000		$5,165,613,000
Derivative contracts, Netting in Consolidated Statement of Financial Condition	-4,729,533,000		-4,759,345,000
Derivative contracts, Net Amounts in Consolidated Statement of Financial Condition	497,092,000		406,268,000
Derivative contracts, Net Amount	497,092,000	[1]	406,268,000	[1]
Securities borrowing arrangements, Gross Amounts	6,566,376,000		6,853,103,000
Securities borrowing arrangements, Net Amounts in Consolidated Statement of Financial Condition	6,566,376,000		6,853,103,000
Securities borrowing arrangements, Additional Amounts Available for Setoff	-526,142,000	[2]	-680,222,000	[2]
Securities borrowing arrangements, Available Collateral	-766,832,000	[3]	-1,274,196,000	[3]
Securities borrowing arrangements, Net Amount	5,273,402,000	[1]	4,898,685,000	[1]
Reverse repurchase agreements, Gross Amounts	11,109,009,000		14,059,133,000
Reverse repurchase agreements, Netting in Consolidated Statement of Financial Condition	-7,363,321,000		-10,132,275,000
Reverse repurchase agreements, Net Amounts in Consolidated Statement of Financial Condition	3,745,688,000		3,926,858,000
Reverse repurchase agreements, Additional Amounts Available for Setoff	-236,325,000	[2]	-634,568,000	[2]
Reverse repurchase agreements, Available Collateral	-3,450,577,000	[3]	-3,248,817,000	[3]
Reverse repurchase agreements, Net Amount	58,786,000	[1]	43,473,000	[1]
Derivative contracts, Gross Amounts	5,133,092,000		5,220,133,000
Derivative contracts, Netting in Consolidated Statement of Financial Condition	-4,810,751,000		-4,856,618,000
Derivative contracts, Net Amounts in Consolidated Statement of Financial Condition	322,341,000		363,515,000
Derivative contracts, Net Amount	322,341,000	[1]	363,515,000	[1]
Securities lending arrangements, Gross Amounts	3,173,512,000		2,598,487,000
Securities lending arrangements, Net Amounts in Consolidated Statement of Financial Condition	3,173,512,000		2,598,487,000
Securities lending arrangements, Additional Amounts Available for Setoff	-526,142,000	[2]	-680,222,000	[2]
Securities lending arrangements, Available Collateral	-2,616,154,000	[3]	-1,883,140,000	[3]
Securities lending arrangements, Net Amount	31,216,000	[1]	35,125,000	[1]
Repurchase agreements, Gross Amounts	18,686,688,000		20,804,432,000
Repurchase agreements, Netting in Consolidated Statement of Financial Condition	-7,363,321,000		-10,132,275,000
Repurchase agreements, Net Amounts in Consolidated Statement of Financial Condition	11,323,367,000		10,672,157,000
Repurchase agreements, Additional Amounts Available for Setoff	-236,325,000	[2]	-634,568,000	[2]
Repurchase agreements, Available Collateral	-10,039,131,000	[3]	-8,810,770,000	[3]
Repurchase agreements, Net Amount	1,047,911,000	[1]	1,226,819,000	[1]
Securities borrowing arrangements, Net Amount, Subject to Review	5,241,500,000		4,847,400,000
Securities borrowing arrangements, Collateral Received, Subject to Review	5,093,800,000		4,694,000,000
Repurchase agreements, Net Amount, Subject to Review	1,038,800,000		1,201,900,000
Repurchase agreements, Collateral Pledged, Subject to Review	$1,073,400,000		$1,238,400,000
[1]	At March 31, 2015, amounts include $5,241.5 million of securities borrowing arrangements, for which we have received securities collateral of $5,093.8 million, and $1,038.8 million of repurchase agreements, for which we have pledged securities collateral of $1,073.4 million, which are subject to master netting agreements but we have not yet determined the agreements to be legally enforceable. At December 31, 2014, amounts include $4,847.4 million of securities borrowing arrangements, for which we have received securities collateral of $4,694.0 million, and $1,201.9 million of repurchase agreements, for which we have pledged securities collateral of $1,238.4 million, which are subject to master netting agreements but we have not yet determined the agreements to be legally enforceable.
[2]	Under master netting agreements with our counterparties, we have the legal right of offset with a counterparty, which incorporates all of the counterparty's outstanding rights and obligations under the arrangement. These balances reflect additional credit risk mitigation that is available by counterparty in the event of a counterparty's default, but which are not netted in the balance sheet because other provisions of GAAP are not met. Further, for derivative assets and liabilities, amounts netted include cash collateral paid or received.
[3]	Includes securities received or paid under collateral arrangements with counterparties that could be liquidated in the event of a counterparty default and thus offset against a counterparty's rights and obligations under the respective repurchase agreements or securities borrowing or lending arrangements.

Intangible_Assets_Net_And_Good2

Intangible Assets, Net And Goodwill (Narrative) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Intangible Assets, Net And Goodwill [Abstract]
Amortization expense on intangible assets	$16.30	$16.60
Future amortization expense, 2015	47.6
Future amortization expense, 2016	63
Future amortization expense, 2017	63.1
Future amortization expense, 2018	63.3
Future amortization expense, 2019	$63.10

Intangible_Assets_Net_And_Good3

Intangible Assets, Net And Goodwill (Schedule Of Intangible Assets, Net And Goodwill) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	$961,161	$978,374
Goodwill	1,741,137	1,742,389
Total intangible assets, net and goodwill	2,702,298	2,720,763
Exchange And Clearing Organization Membership Interests And Registrations [Member]
Intangible Assets [Line Items]
Indefinite lived intangibles	14,501	14,528
Customer And Other Relationships [Member]
Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	483,408	493,501
Intangibles, accumulated amortization	165,060	155,548
Trademarks And Tradename [Member]
Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	343,459	347,883
Intangibles, accumulated amortization	51,254	47,101
Supply Contracts [Member]
Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	116,998	119,562
Intangibles, accumulated amortization	32,997	30,433
Other Intangible Assets [Member]
Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	2,795	2,900
Intangibles, accumulated amortization	4,808	4,703
National Beef [Member]
Intangible Assets [Line Items]
Goodwill	14,991	14,991
Jefferies [Member]
Intangible Assets [Line Items]
Goodwill	1,717,595	1,718,847
Other Operations [Member]
Intangible Assets [Line Items]
Goodwill	$8,551	$8,551

Inventory_Details

Inventory (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Inventory [Abstract]
Finished goods	$364,875	$343,959
Work in process	40,773	40,951
Raw materials, supplies and other	39,184	37,993
Inventory, net	$444,832	$422,903

ShortTerm_Borrowings_Details

Short-Term Borrowings (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Short-Term Borrowings [Abstract]
Interest rates on short-term borrowings outstanding	1.34%
Short-term borrowings	$411,998	$12,000

LongTerm_Debt_Narrative_Detail

Long-Term Debt (Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Apr. 30, 2015
National Beef [Member]
Debt Instrument [Line Items]
Aggregate outstanding letters of credit	$20.10
3.875% Convertible Senior Debentures, due November 1, 2029 [Member]
Debt Instrument [Line Items]
Interest rate	3.88%	3.88%
Shares issuable upon conversion per $1000 debenture	22.2523
Incremental principal amount of notes	$1,000
Conversion price per common share for convertible notes	$44.94
Contingent interest rate percent	0.38%
Trading period for contingent interest	5 days
Minimum average trading price for 5 trading days per $1,000 debenture	$1,200
Common stock price as a percent of conversion price minimum	130.00%
Earliest period of conversion price	20 days
Consecutive trading days	10 days
Consecutive trading days	30 days
Trading price per debenture related to common stock, maximum	95.00%
Debt Instrument Maturity Date	1-Nov-29	1-Nov-29
Revolving Credit Facility [Member] | National Beef [Member]
Debt Instrument [Line Items]
Interest rate	2.90%
Credit facility Term Loan, Maximum amount	300
3.75% Convertible Senior Subordinated Notes Due April 15, 2014 [Member]
Debt Instrument [Line Items]
Interest rate			3.75%
Jefferies Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility Term Loan, Maximum amount	750
Term Loan [Member] | National Beef [Member]
Debt Instrument [Line Items]
Interest rate	2.90%
Credit facility Term Loan, Maximum amount	375
Subsequent Event [Member] | Revolving Credit Facility [Member] | National Beef [Member]
Debt Instrument [Line Items]
Credit facility Term Loan, Maximum amount				375
Minimum [Member] | Revolving Credit Facility And Term Loan [Member] | National Beef [Member]
Debt Instrument [Line Items]
Percentage added to base rate or LIBOR rate	0.75%
Maximum [Member] | Revolving Credit Facility [Member] | National Beef [Member]
Debt Instrument [Line Items]
Amount of revolver available	$98
Maximum [Member] | Revolving Credit Facility And Term Loan [Member] | National Beef [Member]
Debt Instrument [Line Items]
Percentage added to base rate or LIBOR rate	2.75%

LongTerm_Debt_Schedule_Of_Inde

Long-Term Debt (Schedule Of Indebtedness) (Details) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Debt Instrument [Line Items]
Long-term debt	$8,558,783	$8,527,929
8.125% Senior Notes Due September 15, 2015 [Member]
Debt Instrument [Line Items]
Long-term debt	458,040	457,723
Interest rate	8.13%	8.13%
Maturity date	15-Sep-15	15-Sep-15
Principal	458,641	458,641
5.50% Senior Notes due October 18, 2023 [Member]
Debt Instrument [Line Items]
Long-term debt	740,953	740,748
Interest rate	5.50%	5.50%
Maturity date	18-Oct-23	18-Oct-23
Principal	750,000	750,000
6.625% Senior Notes due October 23, 2043 [Member]
Debt Instrument [Line Items]
Long-term debt	247,000	246,991
Interest rate	6.63%	6.63%
Maturity date	23-Oct-43	23-Oct-43
Principal	250,000	250,000
3.75% Convertible Senior Subordinated Notes Due April 15, 2014 [Member]
Debt Instrument [Line Items]
Interest rate			3.75%
3.875% Senior Notes, due November 9, 2015 [Member]
Debt Instrument [Line Items]
Long-term debt	505,851	507,944
Interest rate	3.88%	3.88%
Maturity date	9-Nov-15	9-Nov-15
Principal	500,000	500,000
5.5% Senior Notes, due March 15, 2016 [Member]
Debt Instrument [Line Items]
Long-term debt	360,702	363,229
Interest rate	5.50%	5.50%
Maturity date	15-Mar-16	15-Mar-16
Principal	350,000	350,000
5.125% Senior Notes, due April 13, 2018 [Member]
Debt Instrument [Line Items]
Long-term debt	839,383	842,359
Interest rate	5.13%	5.13%
Maturity date	13-Apr-18	13-Apr-18
Principal	800,000	800,000
8.5% Senior Notes, due July 15, 2019 [Member]
Debt Instrument [Line Items]
Long-term debt	826,229	832,797
Interest rate	8.50%	8.50%
Maturity date	15-Jul-19	15-Jul-19
Principal	700,000	700,000
2.375% Euro Senior Notes, due May 20, 2020 [Member]
Debt Instrument [Line Items]
Long-term debt	558,601	620,725
Interest rate	2.38%	2.38%
Maturity date	20-May-20	20-May-20
Principal	559,850
6.875% Senior Notes, due April 15, 2021 [Member]
Debt Instrument [Line Items]
Long-term debt	849,568	853,091
Interest rate	6.88%	6.88%
Maturity date	15-Apr-21	15-Apr-21
Principal	750,000	750,000
2.25% Euro Medium Term Notes, due July 13, 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	3,956	4,379
Interest rate	2.25%	2.25%
Maturity date	13-Jul-22	13-Jul-22
Principal	4,479
5.125% Senior Notes, due January 20, 2023 [Member]
Debt Instrument [Line Items]
Long-term debt	622,716	623,311
Interest rate	5.13%	5.13%
Maturity date	20-Jan-23	20-Jan-23
Principal	600,000	600,000
6.45% Senior Debentures, due June 8, 2027 [Member]
Debt Instrument [Line Items]
Long-term debt	381,073	381,515
Interest rate	6.45%	6.45%
Maturity date	8-Jun-27	8-Jun-27
Principal	350,000	350,000
3.875% Convertible Senior Debentures, due November 1, 2029 [Member]
Debt Instrument [Line Items]
Long-term debt	348,276	348,568
Interest rate	3.88%	3.88%
Maturity date	1-Nov-29	1-Nov-29
Principal	345,000	345,000
6.25% Senior Debentures, due January 15, 2036 [Member]
Debt Instrument [Line Items]
Long-term debt	512,969	513,046
Interest rate	6.25%	6.25%
Maturity date	15-Jan-36	15-Jan-36
Principal	500,000	500,000
6.50% Senior Notes, due January 20, 2043 [Member]
Debt Instrument [Line Items]
Long-term debt	421,885	421,960
Interest rate	6.50%	6.50%
Maturity date	20-Jan-43	20-Jan-43
Principal	400,000	400,000
Secured credit facility, due June 26, 2017 [Member]
Debt Instrument [Line Items]
Long-term debt	205,000	170,000
Maturity date	26-Jun-17	26-Jun-17
Other [Member]
Debt Instrument [Line Items]
Long-term debt	158,415	119,399
National Beef [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term debt	181,916	135,144
Interest rate	2.90%
National Beef [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Long-term debt	336,250	345,000
Interest rate	2.90%
Parent Company [Member]
Debt Instrument [Line Items]
Long-term debt	1,445,993	1,445,462
Subsidiary [Member]
Debt Instrument [Line Items]
Long-term debt	$7,112,790	$7,082,467

Mezzanine_Equity_Narrative_Det

Mezzanine Equity (Narrative) (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Purchase Requirement [Line Items]
Fair value discount rate	13.00%
Terminal growth rate	2.00%
Mandatorily redeemable convertible preferred shares redemption value	$125,000	$125,000
Redeemable noncontrolling interests	168,541	186,686
3.25% Cumulative Convertible Preferred Shares [Member]
Purchase Requirement [Line Items]
Mandatorily redeemable convertible preferred shares redemption value	125,000
Dividend rate on preferred stock	3.25%
Mandatorily redeemable preferred shares callable price per share	$1,000
Mandatory redeemable preferred stock, effective conversion price per share	$30.03
Mandatory redeemable preferred stock, number of shares in conversion	4,162,200
Conwed Plastics [Member]
Purchase Requirement [Line Items]
Redeemable noncontrolling interests	$2,300	$2,400
National Beef [Member] | December 30, 2016 [Member] | Put Rights [Member]
Purchase Requirement [Line Items]
Put right interest percentage	33.30%
National Beef [Member] | December 30, 2018 [Member] | Put Rights [Member]
Purchase Requirement [Line Items]
Put right interest percentage	33.30%
National Beef [Member] | December 30, 2021 [Member] | Put Rights [Member]
Purchase Requirement [Line Items]
Put right interest percentage	33.30%
USPB [Member] | Maximum [Member] | Call Rights [Member]
Purchase Requirement [Line Items]
Ownership interests as a percent of original interest	20.00%
Other Members [Member] | Maximum [Member] | Call Rights [Member]
Purchase Requirement [Line Items]
Ownership interests as a percent of original interest	50.00%
Anniversary of acquisition	10 years

Mezzanine_Equity_Schedule_Of_R

Mezzanine Equity (Schedule Of Redeemable Noncontrolling Interests) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
As of January 1,	$186,686
Loss allocated to redeemable noncontrolling interests	-7,112	-5,932
Decrease in fair value of redeemable noncontrolling interests credited to additional paid-in capital	-11,033	-755
Balance, March 31,	168,541
National Beef [Member]
As of January 1,	184,333	241,075
Loss allocated to redeemable noncontrolling interests	-7,059	-5,939
Decrease in fair value of redeemable noncontrolling interests credited to additional paid-in capital	-11,033	-755
Balance, March 31,	$166,241	$234,381

Mezzanine_Equity_Sensitivity_A

Mezzanine Equity (Sensitivity Analysis Of Fair Value Of Redeemable Noncontrolling Interests Using Discount And Terminal Growth Rates) (Details) (USD $)	Mar. 31, 2015
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate assumed in determining fair value	13.00%
Terminal growth rate assumed in determining fair value	2.00%
Rate 12.75% Discount Rate [Member] | Rate 1.75% Terminal Growth Rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of redeemable noncontrolling interests	170
Discount rate assumed in determining fair value	12.75%
Terminal growth rate assumed in determining fair value	1.75%
Rate 12.75% Discount Rate [Member] | Rate 2.00% Terminal Growth Rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of redeemable noncontrolling interests	172.2
Discount rate assumed in determining fair value	12.75%
Terminal growth rate assumed in determining fair value	2.00%
Rate 12.75% Discount Rate [Member] | Rate 2.25% Terminal Growth Rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of redeemable noncontrolling interests	174.5
Discount rate assumed in determining fair value	12.75%
Terminal growth rate assumed in determining fair value	2.25%
Rate 13.00% Discount Rate [Member] | Rate 1.75% Terminal Growth Rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of redeemable noncontrolling interests	164.2
Discount rate assumed in determining fair value	13.00%
Terminal growth rate assumed in determining fair value	1.75%
Rate 13.00% Discount Rate [Member] | Rate 2.00% Terminal Growth Rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of redeemable noncontrolling interests	166.2
Discount rate assumed in determining fair value	13.00%
Terminal growth rate assumed in determining fair value	2.00%
Rate 13.00% Discount Rate [Member] | Rate 2.25% Terminal Growth Rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of redeemable noncontrolling interests	168.4
Discount rate assumed in determining fair value	13.00%
Terminal growth rate assumed in determining fair value	2.25%
Rate 13.25% Discount Rate [Member] | Rate 1.75% Terminal Growth Rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of redeemable noncontrolling interests	158.6
Discount rate assumed in determining fair value	13.25%
Terminal growth rate assumed in determining fair value	1.75%
Rate 13.25% Discount Rate [Member] | Rate 2.00% Terminal Growth Rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of redeemable noncontrolling interests	160.5
Discount rate assumed in determining fair value	13.25%
Terminal growth rate assumed in determining fair value	2.00%
Rate 13.25% Discount Rate [Member] | Rate 2.25% Terminal Growth Rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of redeemable noncontrolling interests	162.5
Discount rate assumed in determining fair value	13.25%
Terminal growth rate assumed in determining fair value	2.25%

Common_Shares_And_Compensation1

Common Shares And Compensation Plans (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Common Shares, Compensation Plans And Preferred Shares [Line Items]
Tax benefit for issuance of share-based awards	$11,900,000	$14,000,000
Share-based compensation	32,794,000	38,207,000
Net tax detriment related to share-based compensation plans recognized as additional paid in capital	5,300,000
Shares reserved for stock options and warrants	5,233,906
Total unrecognized compensation cost related to nonvested share-based awards	$88,200,000
Employee service share-based compensation, unrecognized compensation costs on nonvested awards, weighted average period of recognition	1 year 8 months 12 days
Potential maximum increase to common shares outstanding from restricted stock and other shares	13,494,000
Other Shares Issuable [Member]
Common Shares, Compensation Plans And Preferred Shares [Line Items]
Other shares issuable	866,000
Employee [Member]
Common Shares, Compensation Plans And Preferred Shares [Line Items]
Vesting period for options granted	5 years
Director [Member]
Common Shares, Compensation Plans And Preferred Shares [Line Items]
Vesting period for options granted	4 years
Future Service Required [Member] | Restricted Stock Units [Member]
Common Shares, Compensation Plans And Preferred Shares [Line Items]
Restricted shares, Outstanding	4,065,000
Future Service Required [Member] | Restricted Stock [Member]
Common Shares, Compensation Plans And Preferred Shares [Line Items]
Restricted shares, Outstanding	2,572,000
No Future Service Required [Member] | Restricted Stock Units [Member]
Common Shares, Compensation Plans And Preferred Shares [Line Items]
Restricted shares, Outstanding	8,563,000

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Summary Of Accumulated Other Comprehensive Income, Net Of Taxes) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, net	$427,118	$447,082
Net Unrealized Gains (Losses) On Available For Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, net	571,170	577,588
Net Unrealized Foreign Exchange Gains (Losses) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, net	-41,492	-26,771
Net Minimum Pension Liability [Member] | Accumulated Defined Benefit Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, net	($102,560)	($103,735)

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive Income (Schedule Of Accumulated Other Comprehensive Income Reclassifications) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized securities gains	$15,089	$5,394
Amortization of defined benefit pension plan actuarial gains (losses)	-1,175	-760
Income tax provision (benefit)	212,678	56,250
Total reclassifications for the period, net of tax	374,429	91,937
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period, net of tax	4,128	-1,638
Reclassification out of Accumulated Other Comprehensive Income [Member] | Net Unrealized Gains (Losses) On Available For Sale Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized securities gains	5,303	-878
Income tax provision (benefit)	2,944	-488
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of defined benefit pension plan actuarial gains (losses)	-1,175	-760
Income tax provision (benefit)	($653)	($422)

Pension_Plans_And_Postretireme2

Pension Plans And Postretirement Benefits (Narrative) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015
Pension Plans And Postretirement Benefits [Abstract]
Employer contributions	$0

Pension_Plans_And_Postretireme3

Pension Plans And Postretirement Benefits (Components Of Pension Expense) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Pension Plans And Postretirement Benefits [Abstract]
Interest cost	$3,476	$3,774
Service cost		11
Expected return on plan assets	-2,690	-2,536
Actuarial losses	1,912	1,208
Net periodic pension cost	$2,698	$2,457

Income_Taxes_Narrative_Details

Income Taxes (Narrative) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Income Taxes [Line Items]
State income taxes	$8.90	$15.10
Foreign income taxes	2.7	6
Unrecognized tax benefits	178.4
Interest included in unrecognized tax benefits	37.5
Jefferies [Member]
Income Taxes [Line Items]
Unrecognized tax benefits	$148.60

Earnings_Loss_Per_Common_Share2

Earnings (Loss) Per Common Share (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Warrants [Member]
Earnings Per Share [Line Items]
Securities excluded from computation of earnings per share amount	4,000,000	4,000,000
Exercise price	$33.33	$33.33
Employee Stock Option [Member]
Earnings Per Share [Line Items]
Securities excluded from computation of earnings per share amount	1,311,000	773,000
3.75% Convertible Senior Subordinated Notes Due April 15, 2014 [Member]
Earnings Per Share [Line Items]
Convertible notes interest rate		3.75%
3.875% Convertible Senior Debentures, due November 1, 2029 [Member]
Earnings Per Share [Line Items]
Convertible notes interest rate	3.88%		3.88%

Earnings_Loss_Per_Common_Share3

Earnings (Loss) Per Common Share (Earnings Per Share Computation) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
Earnings Per Share [Line Items]
Net income attributable to Leucadia National Corporation common shareholders	$380,759,000		$94,316,000
Allocation of earnings to participating securities	-7,086,000	[1]	-2,397,000	[1]
Net income attributable to Leucadia National Corporation common shareholders for basic earnings (loss) per share	373,673,000		91,919,000
Adjustment to allocation of earnings to participating securities related to diluted shares	54,000	[1]
Mandatorily redeemable convertible preferred share dividends	1,016,000		1,016,000
Interest on 3.75% Convertible Notes			640,000
Net income attributable to Leucadia National Corporation common shareholders for diluted earnings (loss) per share	374,743,000		93,575,000
Denominator for basic earnings (loss) per share - weighted average shares	373,541,000		368,487,000
Stock options	10,000		101,000
Mandatorily redeemable convertible preferred shares	4,162,000		4,162,000
Denominator for diluted earnings (loss) per share	377,713,000		377,348,000
Weighted average shares of participating securities	7,114,000		9,704,400
Dividends declared on participating securities	$400,000		$600,000
3.875% Convertible Senior Debentures, due November 1, 2029 [Member]
Earnings Per Share [Line Items]
Convertible notes interest rate	3.88%				3.88%
3.75% Convertible Senior Subordinated Notes Due April 15, 2014 [Member]
Earnings Per Share [Line Items]
Convertible Debenture/Notes			4,598,000
Convertible notes interest rate			3.75%
[1]	Represents dividends declared during the period on participating securities plus an allocation of undistributed earnings to participating securities. Net losses are not allocated to participating securities. Participating securities represent restricted stock and RSUs for which requisite service has not yet been rendered and amounted to weighted average shares of 7,114,000 and 9,704,400 for the three months ended March 31, 2015 and 2014, respectively.

Commitments_Contingencies_And_1

Commitments, Contingencies And Guarantees (Narrative) (Details) (USD $)	1 Months Ended	3 Months Ended		12 Months Ended	1 Months Ended
	Oct. 31, 2014	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2014	Aug. 31, 2014
		lawsuit
		plaintiff
Commitments Contingencies And Guarantees [Line Items]
Loan commitments outstanding to clients		$353,500,000
Fair value of mortgage-related and other purchase commitments		154,900,000
Fair value of derivative contracts meeting the definition of a guarantee		567,100,000
Amount accrued for estimated probable losses in connection with litigation		20,000,000
Deferred revenue		22,800,000
Approximate number of plaintiffs		124,000
Number of class action lawsuits		7
Maximum legal fees to be reimbursed		27,500,000
Maximum other expenses to be reimbursed		1,100,000
Settlement amount	70,000,000
Litigation expense			3,200,000
Lease obligations		38,000,000
Jefferies Finance [Member]
Commitments Contingencies And Guarantees [Line Items]
Maximum amount payable under guarantee		31,000,000
Berkadia [Member]
Commitments Contingencies And Guarantees [Line Items]
Surety policy issued		2,500,000,000
Reimbursement of losses incurred, maximum percentage		50.00%
Aggregate amount of commercial paper outstanding		2,470,000,000
National Beef [Member]
Commitments Contingencies And Guarantees [Line Items]
Letters of credit		20,100,000
Jefferies [Member]
Commitments Contingencies And Guarantees [Line Items]
Settlement amount				25,000,000
Payments to trading counterparties				11,000,000
Fine payable to the U.S. Attorney's Office				10,000,000
Fine payable to the SEC				4,000,000
Outstanding reserve			1,000,000	1,000,000
Jefferies [Member] | Standby Letters Of Credit [Member]
Commitments Contingencies And Guarantees [Line Items]
Letters of credit		45,900,000
Expiration period maximum		1 year
Other Subsidiaries [Member]
Commitments Contingencies And Guarantees [Line Items]
Letters of credit		22,600,000
Jefferies Capital Partners LLC And Its Private Equity Funds [Member]
Commitments Contingencies And Guarantees [Line Items]
Equity commitments		30,000,000
Other Investments [Member]
Commitments Contingencies And Guarantees [Line Items]
Equity commitments		4,500,000
Folger Hill Asset Management LLC [Member]
Commitments Contingencies And Guarantees [Line Items]
Revolving credit facility					20,000,000
Revolving credit facility term					3 years
Amount Funded under credit facility		$8,300,000

Commitments_Contingencies_And_2

Commitments, Contingencies And Guarantees (Commitments And Contingencies) (Details) (USD $)	Mar. 31, 2015
In Millions, unless otherwise specified
Commitments And Guarantee Obligations [Line Items]
2015	$3,232.60
2016	1,746.50
2017 and 2018	315.9
2019 and 2020	48.3
2021 and Later	193.7
Maximum Payout	5,537
Equity Commitments [Member]
Commitments And Guarantee Obligations [Line Items]
2016	9.2	[1]
2017 and 2018	0.8	[1]
2021 and Later	171.8	[1]
Maximum Payout	181.8	[1]
Loan Commitments [Member]
Commitments And Guarantee Obligations [Line Items]
2015	44.6	[1]
2016	421.7	[1]
2017 and 2018	188.9	[1]
2019 and 2020	48.3	[1]
Maximum Payout	703.5	[1]
Mortgage-Related And Other Purchase Commitments [Member]
Commitments And Guarantee Obligations [Line Items]
2015	1,123.10
2016	1,315.60
2017 and 2018	126.2
Maximum Payout	2,564.90
Forward Starting Reverse Repos And Repos [Member]
Commitments And Guarantee Obligations [Line Items]
2015	2,034.90
Maximum Payout	2,034.90
Other Unfunded Commitments [Member]
Commitments And Guarantee Obligations [Line Items]
2015	30	[1]
2021 and Later	21.9	[1]
Maximum Payout	$51.90	[1]
[1]	Equity, loan and other unfunded commitments are presented by contractual maturity date. The amounts are however available on demand.

Commitments_Contingencies_And_3

Commitments, Contingencies And Guarantees (Credit Exposure From Loan Commitments) (Details) (USD $)	Mar. 31, 2015
In Millions, unless otherwise specified
Commitments And Guarantee Obligations [Line Items]
0 - 12 Months	$128
1 -5 Years	810.6
Total Corporate Lending Exposure	938.6	[1]
Corporate Lending Exposure at Fair Value	235.1	[2]
Corporate Lending Commitments	703.5	[3]
Corporate lending exposure at fair value of funded loans included in trading assets	262
Corporate lending commitments carried at fair value included in trading liabilities	26.9
Non-investment grade [Member]
Commitments And Guarantee Obligations [Line Items]
1 -5 Years	167.6
Total Corporate Lending Exposure	167.6	[1]
Corporate Lending Exposure at Fair Value	2.8	[2]
Corporate Lending Commitments	164.8	[3]
Unrated [Member]
Commitments And Guarantee Obligations [Line Items]
0 - 12 Months	128
1 -5 Years	643
Total Corporate Lending Exposure	771	[1]
Corporate Lending Exposure at Fair Value	232.3	[2]
Corporate Lending Commitments	$538.70	[3]
[1]	Total corporate lending exposure represents the potential loss assuming the fair value of funded loans and lending commitments were zero.
[2]	The corporate lending exposure at fair value includes $262.0 million of funded loans included in Trading assets and a $26.9 million net liability related to lending commitments recorded in Trading liabilities in the Consolidated Statement of Financial Condition as of March 31, 2015.
[3]	Amounts represent the notional amount of unfunded lending commitments.

Commitments_Contingencies_And_4

Commitments, Contingencies And Guarantees (Guarantees) (Details) (USD $)	Mar. 31, 2015
In Millions, unless otherwise specified
Guarantee Obligations [Line Items]
Maximum Payout	$5,537
Derivative Contracts - Non-Credit Related [Member] | Notional [Member]
Guarantee Obligations [Line Items]
2015	37,182.40
2016	2,241.60
2017 and 2018	561.4
2019 and 2020	699.1
2021 and Later	438.9
Maximum Payout	41,123.40
Written Derivative Contracts - Credit Related [Member] | Notional [Member]
Guarantee Obligations [Line Items]
2015	2
2019 and 2020	2,762.20
2021 and Later	84
Maximum Payout	2,848.20
Total Derivative Contracts [Member] | Notional [Member]
Guarantee Obligations [Line Items]
2015	37,184.40
2016	2,241.60
2017 and 2018	561.4
2019 and 2020	3,461.30
2021 and Later	522.9
Maximum Payout	$43,971.60

Commitments_Contingencies_And_5

Commitments, Contingencies And Guarantees (External Credit Ratings Of Underlying Or Referenced Assets For Credit Related Derivatives Contracts) (Details) (USD $)	Mar. 31, 2015
In Millions, unless otherwise specified
Commitments And Guarantee Obligations [Line Items]
Maximum Payout	$5,537
AAA/Aaa [Member] | Index credit default swaps [Member]
Commitments And Guarantee Obligations [Line Items]
External credit ratings	2,772.20
BBB/Baa [Member] | Single name credit default swaps [Member]
Commitments And Guarantee Obligations [Line Items]
External credit ratings	12
Below Investment Grade [Member] | Single name credit default swaps [Member]
Commitments And Guarantee Obligations [Line Items]
External credit ratings	64
Notional/Maximum Payout [Member] | Index credit default swaps [Member]
Commitments And Guarantee Obligations [Line Items]
Maximum Payout	2,772.20
Notional/Maximum Payout [Member] | Single name credit default swaps [Member]
Commitments And Guarantee Obligations [Line Items]
Maximum Payout	$76

Net_Capital_Requirements_Detai

Net Capital Requirements (Details) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Jefferies LLC [Member]
Net Capital Requirements [Line Items]
Net Capital	$954,261
Excess Net Capital	837,399
Jefferies Execution [Member]
Net Capital Requirements [Line Items]
Net Capital	7,132
Excess Net Capital	$6,882

Other_Fair_Value_Information_D

Other Fair Value Information (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term borrowings	$411,998		$12,000
Long-term debt	8,558,783		8,527,929
Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes and loans receivable	249,385	[1]	213,174	[1]
Short-term borrowings	411,998	[2]	12,000	[2]
Long-term debt	8,558,783	[2]	8,527,929	[2]
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes and loans receivable	262,956	[1]	217,171	[1]
Short-term borrowings	411,998	[2]	12,000	[2]
Long-term debt	$8,662,603	[2]	$8,806,700	[2]
[1]	Notes and loans receivable: The fair values are primarily measured using Level 2 and 3 inputs principally based on discounted future cash flows using market interest rates for similar instruments.
[2]	Short-term borrowings and long-term debt: The fair values of short-term borrowings are estimated to be the carrying amount. The fair values of non-variable rate debt are estimated using quoted prices and estimated rates that would be available for debt with similar terms. The fair value of variable rate debt is estimated to be the carrying amount.

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	3 Months Ended		12 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
	item
Related Party Transaction [Line Items]
Purchase commitments	$356.40		$344.80
Sales to related party	9.4	7.4
Purchases from related party	3.6	2.4
Head of cattle to be purchased per year from members of USPB, actual number	735,385
Percentage of cattle requirements obtained through USPB	22.00%	20.00%
Private Equity Related Funds [Member]
Related Party Transaction [Line Items]
Loans to and/or equity investments in related funds	35.9		60.7
Net income (losses) from private equity related funds	-25.2	-2.5
HRG [Member]
Related Party Transaction [Line Items]
Unsettled purchases and sales of loans	248.1		232
Employees [Member]
Related Party Transaction [Line Items]
Loans outstanding to related party	23.3		20.1
HomeFed Corporation [Member]
Related Party Transaction [Line Items]
Cash paid on acquisition of common shares			$14
Common shares acquired			7,500,000
HomeFed Corporation [Member] | Company Chairman [Member]
Related Party Transaction [Line Items]
Ownership percentage of company	4.80%

Discontinued_Operations_Result

Discontinued Operations (Results Of Discontinued Operations) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax benefit	$0	($4,796)
Loss from discontinued operations after income taxes		-8,909
Discontinued Operating Companies [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Investment and other income		810
Total revenues		31,814
Compensation and benefits		1,172
Depreciation and amortization		2,224
Selling, general and other expenses		18,694
Total expenses		45,519
Loss from discontinued operations before income taxes		-13,705
Income tax benefit		-4,796
Loss from discontinued operations after income taxes		-8,909
Gaming Entertainment [Member] | Discontinued Operating Companies [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues		31,004
Expenses		$23,429

Segment_Information_Narrative_

Segment Information (Narrative) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Interest expense	$30,449	$28,576
Unrealized and realized gains and interest income	729,235	281,054
Parent Company [Member]
Segment Reporting Information [Line Items]
Interest expense	24,300	25,200
National Beef [Member]
Segment Reporting Information [Line Items]
Interest expense	4,200	3,100
FXCM [Member]
Segment Reporting Information [Line Items]
Unrealized and realized gains and interest income	$686,600

Segment_Information_Schedule_O

Segment Information (Schedule Of Segment Reporting Information, By Segment) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Net Revenues	$3,184,683	$2,942,524
Total consolidated pre-tax income from continuing operations	587,107	157,096
Depreciation and amortization	52,440	41,487
All Other [Member]
Segment Reporting Information [Line Items]
Net Revenues	737,907	110,950
Total consolidated pre-tax income from continuing operations	641,932	33,147
Depreciation and amortization	7,433	2,359
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net Revenues	-21,000
Parent Company Interest [Member]
Segment Reporting Information [Line Items]
Total consolidated pre-tax income from continuing operations	-24,300	-25,177
Jefferies [Member]
Segment Reporting Information [Line Items]
Net Revenues	591,441	930,512
Total consolidated pre-tax income from continuing operations	12,924	196,370
Depreciation and amortization	22,250	17,031
National Beef [Member]
Segment Reporting Information [Line Items]
Net Revenues	1,856,019	1,887,378
Total consolidated pre-tax income from continuing operations	-33,585	-28,013
Depreciation and amortization	21,787	20,760
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Net Revenues	20,316	13,684
Total consolidated pre-tax income from continuing operations	-9,864	-19,231
Depreciation and amortization	970	1,337
Total Reportable Segment [Member]
Segment Reporting Information [Line Items]
Net Revenues	2,467,776	2,831,574
Total consolidated pre-tax income from continuing operations	-30,525	149,126
Depreciation and amortization	$45,007	$39,128

Subsequent_Events_Narrative_De

Subsequent Events (Narrative) (Details) (USD $)	0 Months Ended
In Millions, unless otherwise specified	Apr. 09, 2015	Mar. 31, 2015
Subsequent Event [Member] | Jefferies [Member]
Subsequent Event [Line Items]
Termination costs, pre-tax	$91.20
Termination costs, after tax	65.8
Termination costs, noncash expense	23
Termination costs, future cash expenditures	68.2
Jefferies Senior Secured Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Revolving credit facility		750
Jefferies Senior Secured Revolving Credit Facility [Member] | Subsequent Event [Member] | Jefferies [Member]
Subsequent Event [Line Items]
Revolving credit facility	750
Unamortized deferred loan origination fees to be expensed	$5.40

Subsequent_Events_Schedule_Of_

Subsequent Events (Schedule Of Client Agreement Termination Costs) (Details) (Subsequent Event [Member], Jefferies [Member], USD $)	0 Months Ended
In Millions, unless otherwise specified	Apr. 09, 2015
Subsequent Event [Member] | Jefferies [Member]
Subsequent Event [Line Items]
Compensation and benefits (including severance costs, retention awards and amortization expense for existing restricted stock and restricted cash compensation awards)	$39.80
Accelerated capitalized software amortization	20.8
Technology and communications service agreements	24.5
Impairment of exchange memberships	2.5
Other expenses	3.6
Total	$91.20