Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Other Product and Service, Other [Member] Principal transactions Principal Transactions Revenue [Member] Principal Transactions Revenue [Member] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Net unrealized losses on available for sale securities Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member] Net unrealized foreign exchange losses Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member] Net unrealized gains (losses) on instrument specific credit risk Accumulated Gain (Loss), Financial Liability, Fair Value Option, Including Portion Attributable to Noncontrolling Interest [Member] Net unrealized gains on cash flow hedges Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest [Member] Amortization of defined benefit pension plan actuarial gains (losses) Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member] Other pension Accumulated Other Pension Adjustment Including Portion Attributable to Noncontrolling Interest [Member] Accumulated Other Pension Adjustment Including Portion Attributable to Noncontrolling Interest [Member] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Revenues and income tax provision (benefit) Other Revenues And Income Tax Provision (Benefit) Other Revenues And Income Tax Provision (Benefit) Other revenues and Selling, general and other expenses Other Revenues and Selling General and Other Expenses Other Revenues and Selling General and Other Expenses Revenues Revenues Reclassification for the period, net of tax Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Reclassification for the period, tax Reclassification from AOCI, Current Period, Tax Earnings Per Share [Abstract] Common Share and Earnings Per Common Share Earnings Per Share [Text Block] Share repurchase program, authorized amount Stock Repurchase Program, Authorized Amount Stock repurchased during period (in shares) Stock Repurchased During Period, Shares Stock repurchased during period Stock Repurchased During Period, Value Remaining authorized repurchase amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Earnings Per Share [Table] Earnings Per Share [Table] Earnings Per Share [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Earnings Per Share [Line Items] Earnings Per Share [Line Items] Earnings Per Share [Line Items] Number of shares authorized to be repurchased Stock Repurchase Program, Number of Shares Authorized to be Repurchased Revenue from Contract with Customer [Abstract] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Equities Equities [Member] Equities [Member] Fixed Income Fixed Income Services [Member] Fixed Income Services [Member] Investment Banking - Capital markets Investment Banking, Capital Markets [Member] Investment Banking, Capital Markets [Member] Investment Banking - Advisory Investment Banking, Advisory [Member] Investment Banking, Advisory [Member] Asset Management Asset Management Services [Member] Asset Management Services [Member] Manufacturing revenues Manufacturing Revenues [Member] Manufacturing Revenues [Member] Oil and gas revenues Oil And Gas Production And Development Revenues [Member] Oil And Gas Production And Development Revenues [Member] Other revenues Revenue From Contract With Customer, Miscellaneous [Member] Revenue From Contract With Customer, Miscellaneous [Member] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Reportable Segments Operating Segments [Member] Consolidation adjustments Segment Reconciling Items [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Jefferies Group Jefferies Group LLC [Member] Jefferies Group LLC Merchant Banking Merchant Banking Segment [Member] Merchant Banking Segment [Member] Corporate Corporate Segment [Member] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Americas Americas [Member] Europe, Middle East and Africa EMEA [Member] Asia Asia [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenue from contracts with customers Revenue from Contract with Customer, Excluding Assessed Tax Equity Method Investments and Joint Ventures [Abstract] Investments In Associated Companies [Table] Investments In Associated Companies [Table] Investments In Associated Companies [Table] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Investment in FXCM Investment in FXCM [Member] Investment in FXCM [Member] Investments In Associated Companies [Line Items] Investments In Associated Companies [Line Items] Investments In Associated Companies [Line Items] Equity method investment, ownership percentage Equity Method Investment, Ownership Percentage Weighted average useful life Weighted Average Life Of Assets and Liabilities With A Basis Difference Weighted Average Life Of Assets and Liabilities With A Basis Difference Segment Reporting [Abstract] Schedule Of Segment Reporting Information, By Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Remainder of current year Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Five Fair Value Disclosures [Abstract] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Corporate equity securities Equity Securities [Member] Corporate debt securities Corporate Debt Securities [Member] Collateralized debt obligations and collateralized loan obligations Collateralized Debt Obligations and Collateralized Loan Obligations [Member] Collateralized Debt Obligations and Collateralized Loan Obligations [Member] U.S. government securities US Treasury and Government [Member] Municipal securities Municipal Bonds [Member] Sovereign obligations Sovereign Debt Securities [Member] Residential mortgage-backed securities Residential Mortgage Backed Securities [Member] Commercial mortgage-backed securities Commercial Mortgage Backed Securities [Member] Other asset-backed securities Other Asset Backed Securities [Member] Other asset-backed securities. Loans and other receivables Loans and Finance Receivables [Member] Investments at fair value Investments at Fair Value [Member] Investments at Fair Value [Member] FXCM term loan FXCM Term Loan [Member] FXCM Term Loan [Member] Loans Loans [Member] U.S. government securities US Treasury Securities [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Fair Value Measured at NAV Fair Value Measured at Net Asset Value Per Share [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Alternative investments Alternative Investment Assets: Financial Instruments, Owned, at Fair Value [Abstract] Trading assets, at fair value Financial Instruments Owned Trading Assets, at Fair Value, Excluding Investments Based on Net Asset Value Financial Instruments Owned Trading Assets, at Fair Value, Excluding Investments Based on Net Asset Value Derivative assets Derivative Asset Counterparty and Cash Collateral Netting, assets Derivative Asset, Fair Value, Gross Liability Securities purchased under agreements to resell Securities Purchased Under Agreements To Resell, at Fair Value Securities Purchased Under Agreements To Resell, at Fair Value Available for sale securities Debt Securities, Available-for-sale Liabilities: Financial Instruments Sold, Not yet Purchased, at Fair Value [Abstract] Trading liabilities, at fair value Trading Liabilities, Fair Value Disclosure Derivative liability Derivative Liability Counterparty and Cash Collateral Netting, liabilities Derivative Liability, Fair Value, Gross Asset Long-term debt Long-term Debt, Fair Value Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations Cash and Securities Segregated under Federal and Other Regulations Debt Disclosure [Abstract] Short-Term Borrowings Short-term Debt [Text Block] Share-based Compensation [Abstract] Compensation Plans Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] CDOs and CLOs Loans and other receivables FXCM term loan Investment in Senior Secured Term Loan [Member] Investment in Senior Secured Term Loan [Member] Securities purchased under agreements to resell Securities Purchased Under Agreements To Resell [Member] Securities Purchased Under Agreements To Resell [Member] Derivatives Derivative [Member] Long-term debt Long-term Debt [Member] Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Assets: Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Beginning Balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Total gains (losses) (realized and unrealized) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Issuances Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances Net transfers into (out of) Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net Ending Balance Fair value, Assets, change in unrealized gains/(losses) included in earnings relating to instruments still held Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Liabilities: Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Beginning Balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Total gains/ losses (realized and unrealized) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Total gains (losses) (realized and unrealized), included in earnings and OCI Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included In Earnings And Other Comprehensive Income (Loss) Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included In Earnings And Other Comprehensive Income (Loss) Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Issuances Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances Net transfers into (out of) Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Transfers, Net Ending Balance Fair value, Liabilities, change in unrealized gains/(losses) included in earnings relating to instruments still held Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss) Fair value, Liabilities, change in unrealized gains/(losses) included in other comprehensive income relating to instruments still held Fair Value, Liabilities Measured On Recurring Basis, Change In Unrealized Gain (Loss) Included In Other Comprehensive Income Fair Value, Liabilities Measured On Recurring Basis, Change In Unrealized Gain (Loss) Included In Other Comprehensive Income Temporary Equity Disclosure [Abstract] Redeemable Noncontrolling Interest, by Legal Entity [Table] Redeemable Noncontrolling Interest, by Legal Entity [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] National Beef National Beef [Member] National Beef [Member] Redeemable Noncontrolling Interest [Line Items] Redeemable Noncontrolling Interest [Line Items] Redeemable Noncontrolling Interest [Roll Forward] Redeemable Noncontrolling Interest [Roll Forward] Redeemable Noncontrolling Interest [Roll Forward] Beginning balance Redeemable Noncontrolling Interest, Equity, Carrying Amount Income allocated to redeemable noncontrolling interests Net Income (Loss) Attributable to Redeemable Noncontrolling Interest Distributions to redeemable noncontrolling interests Payments for Distributions To Redeemable Noncontrolling Interests Payments for Distributions To Redeemable Noncontrolling Interests Increase in fair value of redeemable noncontrolling interests Change In Fair Value Of Redeemable Noncontrolling Interests Change In Fair Value Of Redeemable Noncontrolling Interests Reversal of cumulative National Beef redeemable noncontrolling interests fair value adjustment prior to deconsolidation Reversal Of Cumulative Redeemable Noncontrolling Interests Fair Value Adjustments Prior To Deconsolidation Reversal Of Cumulative Redeemable Noncontrolling Interests Fair Value Adjustments Prior To Deconsolidation Deconsolidation of National Beef Deconsolidation of Subsidiary Deconsolidation of Subsidiary Ending balance Loans and other receivables Fair Value, Option, Aggregate Differences, Loans and Long-term Receivables Loans and other receivables on nonaccrual status and/or 90 days or greater past due Fair Value, Option, Loans Held As Assets, Aggregate Amount In Nonaccrual Status And/Or 90 Days Or Greater Past Due, Aggregated Difference Fair Value, Option, Loans Held As Assets, Aggregate Amount In Nonaccrual Status And/Or 90 Days Or Greater Past Due, Aggregated Difference Long-term Debt Fair Value, Option, Aggregate Differences, Long-term Debt Fair Value, Option, Aggregate Differences, Long-term Debt All loans and other receivables 90 days or greater past due Fair Value, Option, Loans Held as Assets, 90 Days or More Past Due, Aggregate Difference Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Contractual Obligation, Fiscal Year Maturity Schedule [Table Text Block] Guarantees Schedule of Guarantor Obligations [Table Text Block] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Senior secured term loan receivable, principal outstanding Senior Secured Term Loan Receivable, Principal Outstanding Senior Secured Term Loan Receivable, Principal Outstanding Accounting Policies [Abstract] Basis of Presentation and Significant Accounting Policies Basis of Presentation and Significant Accounting Policies [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Fair Value And Related Number Of Derivative Contracts Categorized By Predominant Risk Exposure Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Unrealized And Realized Gains (Losses) On Derivative Contracts Derivative Instruments, Gain (Loss) [Table Text Block] Remaining Contract Maturity Of Fair Value Of OTC Derivative Assets And Liabilities Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Table Text Block] OTC derivatives by risk exposure and maturity profile. Counterparty Credit Quality With Respect To Fair Value Of OTC Derivatives Assets Counterparty Credit Quality With Respect To Fair Value Of Otc Derivatives Assets [Table Text Block] Counterparty credit quality with respect to the fair value of OTC derivatives assets. Credit Related Derivative Contracts Disclosure of Credit Derivatives [Table Text Block] Derivative Instruments With Contingent Features Derivative Instruments With Contingent Features [Table Text Block] Derivative Instruments With Contingent Features [Table Text Block] Derivative [Table] Derivative [Table] External Credit Rating by Grouping [Axis] External Credit Rating by Grouping [Axis] External Credit Rating by Grouping [Domain] External Credit Rating by Grouping [Domain] Investment Grade External Credit Rating, Investment Grade [Member] Non-investment grade External Credit Rating, Non Investment Grade [Member] Unrated Unrated [Member] Unrated [Member] Credit Derivatives Contract Type [Axis] Credit Derivatives Contract Type [Axis] Credit Derivatives Contract Type [Domain] Credit Derivatives Contract Type [Domain] Index credit default swaps Credit Index Product [Member] Single name credit default swaps Credit Default Swap [Member] Derivative [Line Items] Derivative [Line Items] Notional amount Derivative, Notional Amount Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Berkadia Berkadia [Member] Berkadia [Member] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Discontinued operations, disposed of by sale Discontinued Operations, Disposed of by Sale [Member] Disposal group, disposed of by sale, not discontinued operations Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] Garcadia Garcadia [Member] Garcadia Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Parent Company interest Parent Company [Member] Segment Reporting Information [Line Items] Ownership percentage Ownership Percentage Ownership Percentage Percentage of equity method investment for sale Equity Method Investment, Percentage Of Interest Sold Equity Method Investment, Percentage Of Interest Sold Number of reportable segments Number of Reportable Segments Interest expense Interest Expense Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Unusual or Infrequent Item [Axis] Unusual or Infrequent Item, or Both [Axis] Unusual or Infrequent Item [Domain] Unusual or Infrequent Item, or Both [Domain] Future Service Required Future Service Required [Member] Future service required. No Future Service Required No Future Service Required [Member] No future service required. Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Sign-on and Retention Awards Sign-on and Retention Awards [Member] Sign-on and Retention Awards [Member] Restricted Stock Restricted Stock [Member] Restricted Stock Units Restricted Stock Units (RSUs) [Member] Other Shares Issuable Other Shares Issuable [Member] Other Shares Issuable [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Award vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Amortization period Share-Based Compensation Arrangement By Share-Based Payment Award, Amortization Period Share-based Compensation Arrangement by Share-based Payment Award, Amortization Period Share-based compensation Share-based Compensation Tax benefit for issuance of share-based awards Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Total unrecognized compensation cost related to nonvested share-based awards Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Employee service share-based compensation, unrecognized compensation costs on nonvested awards, weighted average period of recognition Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Restricted shares, nonvested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Restricted shares, vested (in shares) Share-Based Compensation Arrangement By Share-Based Payment Award Equity Instruments Other Than Options, Vested, Number Share-Based Compensation Arrangement By Share-Based Payment Award Equity Instruments Other Than Options, Vested, Number Other shares issuable (in shares) Other shares issuable Other shares issuable Potential maximum increase to common shares outstanding from restricted stock and other shares (in shares) Potential Maximum Increase To Common Shares Outstanding From Restricted Stock And Other Shares Potential Maximum Increase to Common Shares Outstanding from Restricted Stock and Other Shares Restricted cash awards, cost expected to be recognized Restricted Cash Awards, Compensation Cost Not Yet Recognized Restricted Cash Awards, Compensation Cost Not Yet Recognized Restricted cash awards, cost expected to be recognized, period Restricted Cash Awards, Compensation Cost Not Yet Recognized, Period For Recognition Restricted Cash Awards, Compensation Cost Not Yet Recognized, Period For Recognition Schedule of Short-term Debt [Table] Schedule of Short-term Debt [Table] Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Bank loans Line of Credit Line of Credit [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Floating rate puttable notes Floating Rate Puttable Notes [Member] Floating Rate Puttable Notes [Member] Jefferies Group Credit Facility Jefferies Group Credit Facility [Member] Jefferies Group Credit Facility [Member] Intraday Credit Facility Intraday Credit Facility [Member] Intraday Credit Facility [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Federal funds effective rate Federal Funds Effective Rate [Member] Federal Funds Effective Rate [Member] Short-term Debt [Line Items] Short-term Debt [Line Items] Short-term borrowings Short-term Debt Interest rates on short-term borrowings outstanding Short-term Debt, Weighted Average Interest Rate, at Point in Time Credit facility maximum amount Line of Credit Facility, Maximum Borrowing Capacity Debt instrument, basic spread on variable rate Debt Instrument, Basis Spread on Variable Rate Investments, Debt and Equity Securities [Abstract] Other investment not readily marketable, fair value Other Investment Not Readily Marketable, Fair Value Investments [Abstract] Schedule of Investments [Table] Schedule of Investments [Table] Schedule of Investments [Line Items] Amortized Cost Debt Securities, Available-for-sale, Amortized Cost Gross Unrealized Gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Gross Unrealized Losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Estimated Fair Value Discontinued Operations and Disposal Groups [Abstract] Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Marfrig Global Foods S.A. Marfrig Global Foods S.A. [Member] Marfrig Global Foods S.A. [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Cash from sale of subsidiary Proceeds from Divestiture of Businesses Ownership percentage to be acquired further from other equity owners Ownership Percentage Acquired From Other Equity Owners Ownership Percentage Acquired From Other Equity Owners Number of directors appointed by Company Number of Directors Appointed by Company Number of Directors Appointed by Company Lockup period related to divestiture of businesses Lockup Period Related To Divestiture Of Businesses Lockup Period Related To Divestiture Of Businesses Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax, Attributable to Parent Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax, Attributable to Parent Income related to associated companies Income (Loss) from Equity Method Investments Distributions received Proceeds From Equity Method Investment Distribution Amount of distribution received from equity method investee for return on investment, classified as operating activities AND distribution for return of investment, classified as investing activities. Consolidated income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Pre-tax gain on disposal of discontinued operations Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax Gain on disposal of discontinued operations, after-tax Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax Pre-tax gain on disposal of discontinued operations, portion related to remeasurement to fair value Discontinued Operation, Gain (Loss) From Disposal Of Discontinued Operation, Before Income Tax, Portion Related To Remeasurement To Fair Value Discontinued Operation, Gain (Loss) From Disposal Of Discontinued Operation, Before Income Tax, Portion Related To Remeasurement To Fair Value Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] HomeFed Homefed Corporation [Member] HomeFed Corporation - Member Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Company Chairman Company Chairman [Member] Company Chairman [Member] HomeFed Shares of common stock owned Investment Owned, Balance, Shares Maximum voting rights as a percentage of total voting securities voting Maximum voting rights as a percentage of total voting securities voting Maximum voting rights as a percentage of total voting securities voting Ownership percentage of company Ownership Percentage of Company Ownership Percentage of Company Number of shares issued per common stock of acquiree Business Acquisition, Equity Interest Issued Or Issuable, Number Of Shares Per Common Stock Of Acquiree Business Acquisition, Equity Interest Issued Or Issuable, Number Of Shares Per Common Stock Of Acquiree Number of shares issued Stock Issued During Period, Shares, New Issues Revenues from Contracts with Customers Revenue from Contract with Customer [Text Block] Related Party Transactions [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] FXCM Fxcm [Member] FXCM Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Payables, expense accruals and other liabilities Payables, Expense Accruals And Other Liabilities [Member] Payables, Expense Accruals And Other Liabilities [Member] Private Equity Related Funds Private Equity Related Funds [Member] Private Equity Related Funds Affiliated Entity Affiliated Entity [Member] Officers and Employees Officers and Employees [Member] Officers and Employees [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Loans to and/or equity investments in related funds Loans to and/or equity investments in related funds Loans to and/or equity investments in related funds Net gains (losses) from private equity related funds Income (Loss) from private equity related funds Income (loss) from private equity related funds Purchase commitment Purchase Commitments Outstanding Purchase Commitments Outstanding OTC foreign exchange contracts Foreign Currency Contracts, Liability, Fair Value Disclosure Loans outstanding to related party Loans and Leases Receivable, Related Parties Restricted Stock with Future Service Required Restricted Stock With Future Service Required [Member] Restricted Stock With Future Service Required [Member] Restricted Stock Units with No Future Service Required Restricted Stock Units With No Future Service Required [Member] Restricted Stock Units With No Future Service Required [Member] Stock options Employee Stock Option [Member] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Senior Executive Compensation Plan Senior Executive Compensation Plan [Member] Senior Executive Compensation Plan [Member] Numerator for earnings per share: Earnings Per Share Reconciliation [Abstract] Net income attributable to Jefferies Financial Group Inc. common shareholders Net Income (Loss) Attributable to Parent Allocation of earnings to participating securities Participating Securities, Distributed and Undistributed Earnings (Loss), Basic Net income attributable to Jefferies Financial Group Inc. common shareholders for basic earnings per share Net Income (Loss) Available to Common Stockholders, Basic Adjustment to allocation of earnings to participating securities related to diluted shares Undistributed Earnings, Diluted Mandatorily redeemable convertible preferred share dividends Convertible Preferred Dividends, Net of Tax Net income attributable to Jefferies Financial Group Inc. common shareholders for diluted earnings per share Net Income (Loss) Available to Common Stockholders, Diluted Denominator for earnings per share: Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Weighted average common shares outstanding Weighted Average Common Shares Outstanding Weighted Average Common Shares Outstanding Weighted average shares of restricted stock outstanding with future service required Weighted Average Number of Shares, Restricted Stock Weighted average RSUs outstanding with no future service required (in shares) Weighted Average Number Of Shares, Restricted Stock Units Weighted Average Number Of Shares, Restricted Stock Units Denominator for basic earnings per share – weighted average shares Weighted Average Number of Shares Outstanding, Basic Dilutive effect of share-based payment awards (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Mandatorily redeemable convertible preferred shares (in shares) Incremental Common Shares Attributable to Redeemable Convertible Preferred Shares Incremental Common Shares Attributable to Redeemable Convertible Preferred Shares Denominator for diluted earnings (loss) per share (in shares) Weighted Average Number of Shares Outstanding, Diluted Weighted average shares of participating securities (in shares) Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights Derivative instrument liabilities with credit-risk-related contingent features Derivative, Net Liability Position, Aggregate Fair Value Collateral posted Collateral Already Posted, Aggregate Fair Value Collateral received Collateral Received, Aggregate Fair Value Collateral Received, Aggregate Fair Value Return of and additional collateral required in the event of a credit rating downgrade below investment grade Additional Collateral, Aggregate Fair Value Commissions and other fees Commission And Other Fees [Member] Commission And Other Fees [Member] Investment banking Investment Banking [Member] Investment Banking [Member] Other Revenue From Contract With Customer, Other [Member] Revenue From Contract With Customer, Other [Member] Interest income Interest Revenue [Member] Interest Revenue [Member] Other Other Sources Of Revenue, Miscellaneous [Member] Other Sources Of Revenue, Miscellaneous [Member] Revenue from other sources Revenue, Other Sources Revenue, Other Sources Total revenues Collateralized Transactions [Abstract] Collateralized Transactions [Abstract] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] Securities or Other Assets Sold under Agreements to Repurchase, Maturity Periods [Axis] Repurchase Agreements and Similar Transactions, Maturity Periods [Axis] Assets Sold under Agreements to Repurchase, Maturity Period [Domain] Repurchase Agreements and Similar Transactions, Maturity Periods [Domain] Overnight and Continuous Maturity Overnight [Member] Up to 30 Days Maturity Less than 30 Days [Member] 30 to 90 Days Maturity 30 to 90 Days [Member] Greater than 90 Days Maturity Greater than 90 Days [Member] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Securities lending arrangements Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred Repurchase agreements Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement Total Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement Discontinued Operations Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Mortgage- and asset-backed securities Mortgage-Backed Securities and Asset-backed Securities [Member] Mortgage-Backed Securities and Asset-backed Securities [Member] U.S. government and federal agency securities US Government Corporations and Agencies Securities [Member] Securitization Activities [Abstract] Securitization Activities [Abstract] Securitization Activities [Table] Securitization Activities [Table] Securitization Activities [Table] CLOs Collateralized Loan Obligations [Member] Consumer and other loans Consumer and Other Loans [Member] Consumer and Other Loans [Member] Securitization Activities [Line Items] Securitization Activities [Line Items] U.S. government agency residential mortgage-backed securities Rmbs Securitization Assets Represents unpaid principal amount of assets in residential mortgage backed securitization vehicles at the balance sheet date. U.S. government agency commercial mortgage-backed securities Cmbs Securitization Assets Represents unpaid principal amount of assets in commercial mortgage backed securitization vehicles at the balance sheet date. CLOs Collateralized Loan Obligations Securitization Assets Collateralized Loan Obligations Securitization Assets Consumer and other loans Consumer and Other Loans Securitization Assets Consumer and Other Loans Securitization Assets Retained Interests Retained Interest, Fair Value Disclosure Consolidation adjustments Consolidation, Eliminations [Member] LAM and Berkadia Transferred Leucadia Asset Management And Berkadia Transferred [Member] Leucadia Asset Management And Berkadia Transferred [Member] Net Revenues Revenues, Net of Interest Expense Depreciation and amortization Depreciation, Depletion and Amortization A- or higher Fair Value Of OTC Derivatives Assets, Counterparty Credit Quality Fair value of OTC derivatives assets, counterparty credit quality A- or higher. BBB- to BBB Fair value of OTC derivatives assets, counterparty credit quality BBB minus to BBB plus Fair value of OTC derivatives assets, counterparty credit quality BBB- to BBB+. BB or lower Fair value of OTC derivatives assets, counterparty credit quality BB plus or lower Fair value of OTC derivatives assets, counterparty credit quality BB or lower. Unrated Fair Value Of Over Counter Derivatives Assets Counterparty Credit Quality Unrated Fair value of OTC derivatives assets, counterparty credit quality unrated. Total OTC derivative assets included in Trading assets Otc Derivative Assets Included In Financial Instruments Owned OTC Derivative Assets Included In Financial Instruments Owned. Mezzanine Equity Mezzanine Equity Disclosure [Text Block] Mezzanine Equity Disclosure [Text Block] Statement of Cash Flows [Abstract] Net cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Adjustments to reconcile net income to net cash used for operations: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Pre-tax income from discontinued operations, including gain on disposal Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax Deferred income tax provision Deferred Income Tax Expense (Benefit), Continuing And Discontinued Operations Deferred Income Tax Expense (Benefit), Continuing And Discontinued Operations Recognition of accumulated other comprehensive income lodged taxes Recognition Of Accumulated Other Comprehensive Income Lodged Taxes Recognition Of Accumulated Other Comprehensive Income Lodged Taxes Depreciation and amortization of property, equipment and leasehold improvements Depreciation and amortization of property equipment and leasehold improvements Depreciation and amortization of property, equipment and leasehold improvements. Other amortization Other Depreciation and Amortization Provision for doubtful accounts Provision for Doubtful Accounts Income related to associated companies Income (Losses) Related to Associated Companies Including Income (Losses) Related to Subsidiary Associated Companies Primarily Classified as Revenues Income (Losses) Related to Associated Companies Including Income (Losses) Related to Subsidiary Associated Companies Primarily Classified as Revenues Distributions from associated companies Dividends Or Distributions From Associated Companies Dividends Or Distributions From Associated Companies Net losses related to property and equipment, and other assets Net gains losses related to property and equipment and other assets Net (gains) losses related to property and equipment, and other assets. Net change in: Increase (Decrease) in Operating Capital [Abstract] Securities deposited with clearing and depository organizations Increase (Decrease) in Securities Deposited with Clearing and Depository Organizations Increase Decrease in Securities Deposited with Clearing and Depository Organizations Trading assets Increase (Decrease) in Debt Securities, Trading, and Equity Securities, FV-NI Securities borrowed Increase (Decrease) in Securities Borrowed Securities purchased under agreements to resell Increase (Decrease) in Securities Purchased Under Agreements to Resell Increase (Decrease) in Securities Purchased Under Agreements to Resell Receivables from brokers, dealers and clearing organizations Increase (Decrease) in Receivables from Brokers-Dealers and Clearing Organizations Receivables from customers of securities operations Increase (Decrease) Receivables from Customers of Securities Operations Increase (Decrease) Receivables from Customers of Securities Operations Other receivables Increase (Decrease) in Other Receivables Other assets Increase (Decrease) In Other Assets Increase Decrease In Other Assets Trading liabilities Increase (Decrease) in Trading Liabilities Securities loaned Increase (Decrease) in Securities Loaned Transactions Securities sold under agreements to repurchase Increase (Decrease) in Payables under Repurchase Agreements Payables to brokers, dealers and clearing organizations Increase (Decrease) in Payables to Broker-Dealers and Clearing Organizations Payables to customers of securities operations Increase (Decrease) in Payables to Customers Trade payables, expense accruals and other liabilities Increase (Decrease) in Trade Payables Expense Accruals and Other Liabilities Increase (Decrease) in Trade Payables Expense Accruals and Other Liabilities Other Increase (Decrease) in Other Operating Assets and Liabilities, Net Net cash used for operating activities - continuing operations Net Cash Provided by (Used in) Operating Activities, Continuing Operations Net cash provided by operating activities - discontinued operations Cash Provided by (Used in) Operating Activities, Discontinued Operations Net cash used for operating activities Net Cash Provided by (Used in) Operating Activities Net cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Acquisitions of property, equipment and leasehold improvements, and other assets Payments to Acquire Property, Plant, and Equipment, and Other Assets Payments to Acquire Property, Plant, and Equipment, and Other Assets Proceeds from disposals of property and equipment, and other assets Proceeds from disposals of property and equipment, and other assets Proceeds from disposals of property and equipment, and other assets. Advances on notes, loans and other receivables Payments to Acquire Receivables Collections on notes, loans and other receivables Proceeds from Sale and Collection of Receivables Loans to and investments in associated companies Payments to Acquire Interest in Subsidiaries and Affiliates Capital distributions and loan repayments from associated companies Capital distributions and loan repayments from associated companies Capital distributions and loan repayments from associated companies. Purchases of investments (other than short-term) Payments to Acquire Investments Proceeds from maturities of investments Proceeds from maturities of investments Proceeds from maturities of investments. Proceeds from sales of investments Proceeds from sales of investments Proceeds from sales of investments. Other Payments for (Proceeds from) Other Investing Activities Net cash provided by (used for) investing activities - continuing operations Net Cash Provided by (Used in) Investing Activities, Continuing Operations Net cash provided by investing activities - discontinued operations Cash Provided by (Used in) Investing Activities, Discontinued Operations Net cash provided by investing activities Net Cash Provided by (Used in) Investing Activities Net cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Issuance of debt, net of issuance costs Proceeds from Other Debt Repayment of debt Repayments of Other Debt Net change in other secured financings Net change in other secured financings Net change in other secured financings Net change in bank overdrafts Proceeds from (Repayments of) Bank Overdrafts Distributions to noncontrolling interests Payments to Noncontrolling Interests Contributions from noncontrolling interests Proceeds from Noncontrolling Interests Purchase of common shares for treasury Payments for Repurchase of Common Stock Dividends paid Payments of Ordinary Dividends, Common Stock Other Proceeds from (Payments for) Other Financing Activities Net cash provided by financing activities - continuing operations Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net cash provided by financing activities - discontinued operations Cash Provided by (Used in) Financing Activities, Discontinued Operations Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Net decrease in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash, cash equivalents and restricted cash at beginning of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, cash equivalents and restricted cash at end of period Redeemable Noncontrolling Interests in Subsidiary [Table] Redeemable Noncontrolling Interests in Subsidiary [Table] Redeemable Noncontrolling Interests in Subsidiary [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] 3.25% Cumulative Convertible Preferred Shares Redeemable Convertible Preferred Stock [Member] Purchase Requirement [Line Items] Purchase Requirement [Line Items] Redeemable noncontrolling interests Redeemable Noncontrolling Interest, Equity, Other, Carrying Amount Dividend rate on preferred stock Preferred Stock, Dividend Rate, Percentage Mandatorily redeemable convertible preferred shares redemption value Mandatorily redeemable convertible preferred shares Mandatorily Redeemable Convertible Preferred Shares Mandatorily redeemable preferred stock, number of shares in conversion Mandatorily Redeemable Preferred Stock, Number of Shares In Conversion Mandatorily Redeemable Preferred Stock, Number of Shares in Conversion Mandatorily redeemable preferred stock, effective conversion price per share (in dollars per share) Mandatorily Redeemable Preferred Stock, Effective Conversion Price Per Share Mandatorily Redeemable Preferred Stock, Effective Conversion Price per Share Minimum dividend considered for additional quarterly payments (in dollars per share) Preferred Stock, Minimum Common Dividend Considered For Additional Quarterly Payments Preferred Stock, Minimum Common Dividend Considered For Additional Quarterly Payments Dividends per common share (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Preferred stock dividend Preferred Stock Dividends, Income Statement Impact Mandatorily redeemable preferred shares callable price per share (in dollars per share) Mandatorily redeemable preferred shares callable price per share Mandatorily redeemable preferred shares callable price per share Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Table] Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Table] Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Table] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Commodity swaps, options and forwards Commodity Swaps Options And Forwards [Member] Commodity swaps options and forwards. Equity swaps and options Equity Swaps And Options [Member] Equity Swaps And Options [Member] Credit default swaps Total return swaps Total Return Swap [Member] Foreign currency forwards, swaps and options Foreign Currency Forwards Swaps And Options [Member] Foreign currency forwards swaps and options. Fixed income forwards Fixed Income Forwards [Member] Fixed income forwards. Interest rate swaps Interest Rate Swap [Member] Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items] Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items] 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 Otc Derivative Assets Having Maturity Period Of Zero To Twelve Months Over the counter derivative assets having maturity period of zero to twelve months. OTC derivative assets having maturity period of 1 to 5 years Otc Derivative Assets Having Maturity Period Of One To Five Years OTC derivative assets having maturity period of 1 to5 years. OTC derivative assets having maturity period of greater than 5 years Otc Derivative Assets Having Maturity Period Of Greater Than Five Years OTC derivative assets having maturity period of greater than five years. OTC derivative assets cross-maturity netting Otc Derivative Assets Cross Maturity Netting OTC derivative assets cross maturity netting. Total OTC derivative assets, net of cross-maturity netting Consolidated Otc Derivative Assets Net Of Crossmaturity Netting Total OTC derivative assets, net of cross-maturity netting. Cross product counterparty netting Derivative Assets Cross Product Counterparty Netting Derivative Assets Cross Product Counterparty Netting. OTC derivative liabilities having maturity period of 0 to 12 months Otc Derivative Liabilities Having Maturity Period Of Zero To Twelve Months OTC derivative liabilities having maturity period of zero to twelve months. OTC derivative liabilities having maturity period of 1 to 5 years Otc Derivative Liabilities Having Maturity Period Of One To Five Years OTC derivative liabilities having maturity period of 1 to 5 years. OTC derivative liabilities having maturity period of greater than 5 years Otc Derivative Liabilities Having Maturity Period Of Greater Than Five Years OTC derivative liabilities having maturity period of greater than 5 years. OTC derivative liabilities cross-maturity netting Otc Derivative Liabilities Cross Maturity Netting OTC derivative liabilities cross maturity netting. Total OTC derivative liabilities, net of cross-maturity netting Consolidated Otc Derivative Liabilities Net Of Crossmaturity Netting Total OTC derivative liabilities, net of cross-maturity netting. Cross product counterparty netting Derivative Liabilities Cross Product Counterparty Netting Derivative Liabilities Cross Product Counterparty Netting. Total OTC derivative liabilities included in Trading liabilities OTC Derivative Liabilities Included In Trading Liabilities OTC Derivative Liabilities Included In Trading Liabilities Exchange traded derivative assets and other credit agreements Exchange traded derivative assets and other credit agreements Exchange traded derivative assets and other credit agreements Cash collateral received Cash Collateral Received Cash collateral received that was netted against OTC derivative assets. Exchange traded derivative liabilities and other credit agreements Exchange traded derivative liabilities and other credit agreements Exchange traded derivative liabilities and other credit agreements Cash collateral pledged Cash collateral pledged Cash collateral pledged that was netted against OTC derivative liabilities. Aggregate Indebtedness [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Secured Debt Secured Debt [Member] Structured Notes Structured Notes [Member] Structured Notes [Member] 8.50% Senior Notes, due July 15, 2019 Eight Point Five Percentage Senior Notes Due Two Thousand Nineteen [Member] 8.5% Senior Notes, due 2019. Revolving Credit Facility Revolving Credit Facility [Member] Foursight Capital Credit Facilities Foursight Credit Facilities [Member] Foursight Credit Facilities [Member] Foursight Capital Foursight Capital [Member] Foursight Capital [Member] Debt Instrument [Line Items] Principal amount of debt issued, net of retirements Debt Instrument, Issued During Period, Principal Amount, Net Of Retirements Debt Instrument, Issued During Period, Principal Amount, Net Of Retirements Repayments of debt Repayments of Debt Debt face amount Debt Instrument, Face Amount Interest rate Debt Instrument, Interest Rate, Stated Percentage Number of warehouse credit commitment Number of Warehouse Credit Commitments Number of Warehouse Credit Commitments Assets pledged for indebtedness Assets pledged for indebtedness Assets pledged for indebtedness Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Related Party Transactions Related Party Transactions Disclosure [Text Block] Schedule of Short-term Borrowings Schedule of Short-term Debt [Table Text Block] Berkadia Capital contributed Capital Contributed Capital Contributed Percentage of profits received from joint venture Percentage Of Profits Received From Joint Venture Percentage Of Profits Received From Joint Venture Surety policy issued Surety policy issued Surety policy issued Reimbursement of losses incurred, maximum percentage Reimbursement Of Losses Incurred, Maximum Percentage Reimbursement of losses incurred, maximum percentage. Commercial paper Commercial Paper Variable Interest Entities [Abstract] Variable Interest Entities [Abstract] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Securitization Vehicles Securitization Vehicles [Member] Securitization Vehicles [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Securities purchased under agreement to resell Securities Purchased under Agreements to Resell Receivables Receivables Receivables Other Other Assets Total assets Assets Other secured financings Other Secured Financings Other Other Liabilities Total liabilities Liabilities Secured financings eliminated in consolidation Secured financings eliminated in consolidation Secured financings eliminated in consolidation Intercompany payables Intercompany Payables Intercompany Payables Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Summary of results of discontinued operations Disposal Groups, Including Discontinued Operations [Table Text Block] Net Capital Requirements [Abstract] Net Capital Requirements [Abstract] Net Capital Requirements Regulatory Capital Requirements Disclosure [Text Block] Regulatory capital requirements disclosure. Net Capital Requirements [Table] Net Capital Requirements [Table] Net Capital Requirements [Table] Jefferies LLC Jefferies LLC [Member] Jefferies LLC [Member] Net Capital Requirements [Line Items] Net Capital Requirements [Line Items] Net Capital Requirements [Line Items] Net capital Net Capital Excess net capital Alternative Excess Net Capital Offsetting [Abstract] Securities borrowing arrangements, Assets Offsetting Securities Borrowed [Abstract] Gross Amounts Securities Borrowed, Gross Netting in Consolidated Statements of Financial Condition Securities Borrowed, Liability Net Amounts in Consolidated Statements of Financial Condition Securities Borrowed Additional Amounts Available for Setoff Securities Borrowed, Collateral, Obligation to Return Cash Available Collateral Securities Borrowed, Collateral, Obligation to Return Securities Net Amount Securities Borrowed, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election Reverse repurchase agreements, Assets Offsetting Securities Purchased under Agreements to Resell [Abstract] Gross Amounts Securities Purchased under Agreements to Resell, Gross Netting in Consolidated Statements of Financial Condition Securities Purchased under Agreements to Resell, Liability Net Amounts in Consolidated Statements of Financial Condition Additional Amounts Available for Setoff Securities Purchased under Agreements to Resell, Collateral, Obligation to Return Cash Available Collateral Securities Purchased under Agreements to Resell, Collateral, Obligation to Return Securities Net Amount Securities Purchased under Agreements to Resell, Amount Offset Against Collateral Securities lending arrangements, Liabilities Offsetting Securities Loaned [Abstract] Gross Amounts Securities Loaned, Gross Netting in Consolidated Statements of Financial Condition Securities Loaned, Asset Net Amounts in Consolidated Statements of Financial Condition Securities Loaned Additional Amounts Available for Setoff Securities Loaned, Collateral, Right to Reclaim Cash Available Collateral Securities Loaned, Collateral, Right to Reclaim Securities Net Amount Securities Loaned, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election Repurchase agreements, Liabilities Offsetting Securities Sold under Agreements to Repurchase [Abstract] Gross Amounts Securities Sold under Agreements to Repurchase, Gross Netting in Consolidated Statements of Financial Condition Securities Sold under Agreements to Repurchase, Asset Net Amounts in Consolidated Statements of Financial Condition Securities Sold under Agreements to Repurchase Additional Amounts Available for Setoff Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Cash Available Collateral Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities Net Amount Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral Securities borrowing agreement, subject to review Securities Borrowed Asset, Net, Subject to Review Securities Borrowed Asset, Net, Subject to Review Securities borrowing agreement, collateral received, subject to review Securities Borrowed Asset, Collateral Received, Subject to Review Securities Borrowed Asset, Collateral Received, Subject to Review Repurchase agreement, net amount, subject to review Securities Sold under Agreements to Repurchase, Net Amount, Subject to Review Securities Sold under Agreements to Repurchase, Net Amount, Subject to Review Repurchase agreements, collateral pledged, subject to review Securities Sold under Agreements to Repurchase, Collateral Pledged, Subject to Review Securities Sold under Agreements to Repurchase, Collateral Pledged, Subject to Review Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations Cash And Securities Segregated And On Deposit For Regulatory Purposes Or Deposited With Clearing And Depository Organizations Cash And Securities Segregated And On Deposit For Regulatory Purposes Or Deposited With Clearing And Depository Organizations Other assets Restricted Cash, Other Assets Restricted Cash, Other Assets Total cash, cash equivalents and restricted cash Schedule Of Assets And Liabilities Measured On Recurring Basis At Fair Value Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Investments Measured At Fair Value Based On Net Asset Value Investments Measured At Fair Value Based On Net Asset Value [Table Text Block] Investments Measured At Fair Value Based On Net Asset Value Summary Of Changes In Fair Value Of Financial Assets And Liabilities Classified As Level 3 Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table Text Block] Reconciliation of beginning Level 3 assets and liabilities to ending Level 3 assets and liabilities (specifically disaggregating purchases, sales, settlements, issuances, transfers to Level 3 and transfers out of Level 3). Quantitative Information About Significant Unobservable Inputs Used In Level 3 Fair Value Measurements Fair Value Inputs Assets And Liabilities Quantitative Information [Table Text Block] Tabular disclosure of quantitative information about significant unobservable inputs used in the fair value measurement of Level 3 financial assets and liabilities, including valuation technique and range of inputs 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 Fair Value Option, Disclosures [Table Text Block] Summary Of Amount By Which Contractual Principal Exceeds Fair Value For Loans And Other Receivables Measured At Fair Value Under Fair Value Option Schedule Of Financial Instrument Contractual Principal In Excess Of Fair Value [Table Text Block] Schedule of financial instrument contractual principal in excess of fair value. Derivative Instruments, Gain (Loss) by Hedging Relationship, by Income Statement Location, by Derivative Instrument Risk [Table] Derivative Instruments, Gain (Loss) [Table] Liability Class [Axis] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Interest rate swaps Derivative Financial Instruments, Liabilities [Member] Long-term Debt Interest rate contracts Interest Rate Contract [Member] Foreign exchange contracts Foreign Exchange Contract [Member] Equity contracts Equity Contract [Member] Commodity contracts Commodity Contract [Member] Credit contracts Credit Risk Contract [Member] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Gains (losses) recognized in Interest expense on fair value hedge Gain (Loss) on Fair Value Hedges Recognized in Earnings Unrealized and realized gains (losses) Gain (Loss) on Derivative Instruments, Net, Pretax Linkem Linkem [Member] Linkem [Member] Percentage of ownership upon conversion of note Ownership Percentage Upon Conversion Of Preferred Shares Ownership Percentage Upon Conversion of Preferred Shares Equity method investment, voting percentage Equity Method Investment, Voting Percentage The voting percentage of common stock or equity participation in the investee accounted for under the equity method of accounting. Shareholder loans principal outstanding Equity Method Investment, Shareholder Loans To Investee, Principal Outstanding Equity Method Investment, Shareholder Loans To Investee, Principal Outstanding Shareholder loans interest rate Equity Method Investment, Shareholder Loans To Investee, Interest Rate Equity Method Investment, Shareholder Loans To Investee, Interest Rate HRG Hrg Group [Member] HRG Group [Member] Spectrum Brands Spectrum Brands Holdings, Inc. [Member] Spectrum Brands Holdings, Inc. [Member] HRG Group/Spectrum Brands Holdings, Inc. HRG Group/Spectrum Brands Holdings, Inc. [Member] HRG Group/Spectrum Brands Holdings, Inc. [Member] Loans and other receivables on nonaccrual status and/or 90 days or greater past due Fair Value, Option, Loans Held As Assets, Aggregate Amount In Nonaccrual Status And/Or 90 Days Or Greater Past Due Fair Value, Option, Loans Held As Assets, Aggregate Amount In Nonaccrual Status And/Or 90 Days Or Greater Past Due Loans and other receivables 90 days or greater past due Fair Value, Option, Loans Held as Assets, 90 Days or More Past Due Shares owned, number Percentage of outstanding common stock owned Percentage of Shares Owned Percentage of Shares Owned Financial instruments owned trading assets, at fair value Financial instruments owned trading assets, at fair value Financial Instruments, Owned, Trading Assets, at Fair Value Cash consideration paid for shares Cash consideration paid for shares Cash consideration paid for shares Changes in fair value of investments reflected as principal transactions Changes in Fair Value of Investments Reflected as Principal Transactions Changes in Fair Value of Investments Reflected as Principal Transactions Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table] Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table] WeWork WeWork [Member] WeWork [Member] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Equity Long/Short Hedge Funds Hedge Funds, Equity Long (Short) [Member] Equity Funds Equity Funds [Member] Commodity Funds Commodity Funds [Member] Commodity Funds [Member] Multi-asset Funds Multi-asset Funds [Member] Multi-asset Funds [Member] Other funds Other Funds [Member] Other Funds [Member] Investments Redeemable Prior Written Notice Period [Axis] Investments Redeemable Prior Written Notice Period [Axis] Investments Redeemable Prior Written Notice Period [Axis] Investments Redeemable Prior Written Notice Period [Domain] Investments Redeemable Prior Written Notice Period [Domain] Investments Redeemable Prior Written Notice Period [Axis] 45 to 90 days prior written notice 45 To 90 Days Prior Written Notice [Member] 45 To 90 Days Prior Written Notice [Member] 60 days prior written notice Sixty Days Prior Written Notice [Member] Sixty Days Prior Written Notice [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items] Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items] Fair Value Unfunded Commitments Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments Percentage of investment at fair value, redemption restriction Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Redemption Restriction, Percentage Investment redemption restriction period Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Redemption Restriction, Period in Effect Investment redemption restriction period remaining Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Redemption Restriction Period Notice period redemption of investments prior written notice period Notice Period Redemption Of Investments Prior Written Notice Period Investments at fair value that cannot be redeemed at reporting date and are subject to a prior written redemption request. Percentage of investments redeemable Percentage Of Investments Redeemable Percentage Of Investments Redeemable Estimated period for the liquidation of the underlying assets Estimated period for the liquidation of the underlying assets Estimated period for the liquidation of the underlying assets, Payments to acquire investments Trading assets, at fair value Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Net unrealized gains on available for sale securities Net unrealized gains on cash flow hedges Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] Net minimum pension liability AOCI Including Portion Attributable to Noncontrolling Interest AOCI Including Portion Attributable to Noncontrolling Interest [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Securities pledged Pledged Financial Instruments, Not Separately Reported, Securities Stockholders' Equity Attributable to Parent [Abstract] Stockholders' Equity Attributable to Parent [Abstract] Common shares, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common shares, authorized (in shares) Common Stock, Shares Authorized Common shares, issued and outstanding after deducting shares held in treasury (in shares) Common Stock, Shares, Outstanding Treasury stock (in shares) Treasury Stock, Shares Statement [Table] Statement [Table] Variable interest entities Variable Interest Entity, Primary Beneficiary [Member] Statement [Line Items] Statement [Line Items] Assets Liabilities Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-lived Intangible Assets, Major Class Name [Domain] Exchange and clearing organization membership interests and registrations Exchange Clearing Organizations And Other Memberships [Member] Exchange, Clearing Organizations And Other Memberships [Member] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Customer and other relationships Customer And Other Relationships [Member] Customer And Other Relationships [Member] Trademarks and tradename Trademarks and Trade Names [Member] Other Other Intangible Assets [Member] Other operations Other Operations [Member] Other Operations Intangible Assets [Line Items] Intangible Assets [Line Items] Indefinite lived intangibles Indefinite-lived Intangible Assets (Excluding Goodwill) Intangible assets, net (excluding goodwill) Intangible Assets, Net (Excluding Goodwill) Goodwill Total intangible assets, net and goodwill Intangible Assets, Net (Including Goodwill) Intangibles, accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Available for Sale Securities and Other Investments Investment Holdings [Text Block] Non-exchange-traded securities Non Exchange Traded Securities [Member] Non Exchange Traded Securities [Member] Private equity securities Private Equity Securities [Member] Private Equity Securities [Member] Measurement Input Type [Axis] Measurement Input Type [Axis] Measurement Input Type [Domain] Measurement Input Type [Domain] Price Measurement Input, Offered Price [Member] Transaction level Measurement Input, Transaction Level [Member] Measurement Input, Transaction Level [Member] Underlying stock price Measurement Input, Share Price [Member] Discount rate/yield Measurement Input, Discount Rate [Member] Estimated recovery percentage Measurement Input, Estimated Recovery Percentage [Member] Measurement Input, Estimated Recovery Percentage [Member] Constant prepayment rate Measurement Input, Prepayment Rate [Member] Constant default rate Measurement Input, Default Rate [Member] Loss severity Measurement Input, Loss Severity [Member] Cumulative loss rate Measurement Input, Cumulative Loss Rate [Member] Measurement Input, Cumulative Loss Rate [Member] Duration (years) Measurement Input, Expected Term [Member] Comparable price Measurement Input, Comparable Asset Price [Member] Measurement Input, Comparable Asset Price [Member] Revenue growth Measurement Input, Long-term Revenue Growth Rate [Member] Volatility Measurement Input, Price Volatility [Member] Term based on the pay off (years) Measurement Input, Maturity [Member] Spread to 6 month LIBOR Measurement Input, Spread To 6 Month LIBOR [Member] Measurement Input, Spread To 6 Month LIBOR [Member] Default probability Measurement Input, Default Probability [Member] Measurement Input, Default Probability [Member] Basis points upfront Measurement Input, Basis Points [Member] Measurement Input, Basis Points [Member] Equity options Equity Option [Member] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Domain] Valuation Approach and Technique [Domain] Discounted cash flows Discounted Cash Flows [Member] Discounted Cash Flows [Member] Scenario analysis Scenario Analysis [Member] Scenario Analysis [Member] Market approach Valuation, Market Approach [Member] Contingent claims analysis Contingent Claims Analysis [Member] Contingent Claims Analysis [Member] Option model/default rate Option Model / Default Rate [Member] Option Model / Default Rate [Member] Volatility benchmarking Volatility Benchmarking [Member] Volatility Benchmarking [Member] Weighted Average Weighted Average [Member] Trading assets, fair value Trading Assets, At Fair Value Trading Assets, At Fair Value Trading assets, measurement input Trading Assets, Measurement Input Trading Assets, Measurement Input Trading assets, measurement input, term Trading Assets, Measurement Input, Term Trading Assets, Measurement Input, Term Securities purchased under agreements to resell Derivative asset, measurement input Derivative Asset, Measurement Input Securities purchased under agreements to resell, measurement input Securities Purchased Under Agreements To Resell, Measurement Input Securities Purchased Under Agreements To Resell, Measurement Input Securities purchased under agreements to resell, measurement input, term Securities Purchased Under Agreements To Resell, Measurement Input, Term Securities Purchased Under Agreements To Resell, Measurement Input, Term Debt instrument, fair value Debt Instrument, Fair Value Disclosure Debt instrument, measurement input Debt Instrument, Measurement Input Derivative liability, measurement input Derivative Liability, Measurement Input Long-term debt, fair value Long-term debt, measurement input Long-term Debt, Measurement Input Schedule of Guarantor Obligations [Table] Schedule of Guarantor Obligations [Table] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Derivative contracts – non-credit related Derivative Contracts Non Credit Related [Member] Derivative contracts - non credit related. Written derivative contracts – credit related Derivative Contracts Credit Related [Member] Derivative contracts - credit related. Derivative Notional Amount Derivative Notional Amount [Member] Derivative Notional Amount [Member] Guarantee Obligations [Line Items] Guarantor Obligations [Line Items] 2019 Guarantees Expected To Be Due, Remainder Of Fiscal Year Guarantees with a remaining term that matures during the fiscal year. These may include derivative guarantees, etc. 2020 Guarantees Expected To Be Due In Second Year Guarantees expected to be due within 2 year. These may include, derivative guarantees, etc. 2021 and 2022 Guarantees Expected To Be Due In Three And Four Years Guarantees expected to be due within 3 to 4 fiscal years. These may include, derivative guarantees, etc. 2023 and 2024 Guarantees Expected To Be Due In Five And Six Years Guarantees expected to be due within 5 to 6 fiscal years. These may include, derivative guarantees, etc. 2025 and Later Guarantees Expected To Be Due in Seventh Year And Thereafter Guarantees expected to be due within 6 fiscal years and thereafter. These may include, derivative guarantees, etc Notional/ Maximum Payout Guarantor Obligations, Maximum Exposure, Undiscounted Earnings Per Share Computation Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Statement of Stockholders' Equity [Abstract] Common Shares $1 Par Value Common Stock [Member] Additional Paid-In Capital Additional Paid-in Capital [Member] Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Retained Earnings Retained Earnings [Member] Subtotal Parent [Member] Noncontrolling Interests Noncontrolling Interest [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning Balance Cumulative effect of the adoption of accounting standards Cumulative Effect of New Accounting Principle in Period of Adoption Beginning Balance, Adjusted Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance Net income Profit Loss Excluding Net Income Loss Attributable To Redeemable Noncontrolling Interests Profit Loss Excluding Net Income Loss Attributable To Redeemable Noncontrolling Interests