Transfers and Servicing [Abstract] Activity Related to Securitizations Accounted for as Sales Summary Of Securitization Arrangements Activity [Table Text Block] Tabular disclosure of the amount of financial assets securitized, proceeds and net revenues and cash flows received from retained interests. Summary of Retained Interests in SPEs Securitization Activities And Variable Interest Entity Table [Table Text Block] Total information regarding securitization vehicles to which Jefferies, acting as transferor, have transferred assets and for which the Company received sale accounting treatment. Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] 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 relationships Customer Relationships [Member] Trade name Trade Names [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Gross costs - finite lived intangible assets Finite-Lived Intangible Assets, Gross Accumulated amortization - finite lived intangible assets Finite-Lived Intangible Assets, Accumulated Amortization Net carrying amount - finite lived intangible assets Finite-Lived Intangible Assets, Net Weighted average remaining lives (years) Finite-Lived Intangible Asset, Useful Life Schedule of Indefinite-Lived Intangible Assets [Table] Schedule of Indefinite-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 ownership interests and registrations Exchange And Clearing Organization Membership Interests And Registrations [Member] Exchange and clearing organization membership interests and registrations. Indefinite-lived Intangible Assets [Line Items] Indefinite-lived Intangible Assets [Line Items] Gross costs - indefinite lived intangible assets Indefinite Lived Intangible Assets Gross Indefinite lived Intangible asset Gross (before impairment). Total gross costs - intangible assets Intangible Assets, Gross (Excluding Goodwill) Disposals Indefinite Lived Intangible Assets, Disposals Indefinite Lived Intangible Assets, Disposals Impairment losses Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill) Intangible Assets Acquired Indefinite-lived Intangible Assets Acquired Net carrying amount - indefinite lived intangible assets Indefinite Lived Intangible Asset Net Cost (After Impairment) Indefinite Lived Intangible Asset Net Cost (After Impairment) Total net carrying amount - intangible assets Intangible Assets, Net (Excluding Goodwill) Commitments and Contingencies Disclosure [Abstract] Commitments, Contingencies and Guarantees Commitments Contingencies and Guarantees [Text Block] Equity Method Investments and Joint Ventures [Abstract] Assets and Liabilities of Consolidated VIEs Prior to Consolidation Variable Interest Entities Primary Beneficiary [Table Text Block] Variable Interest Entities Primary Beneficiary [Table Text Block] Variable Interests in Non-Consolidated Variable Interest Entities Non Consolidated Variable Interest Entities [Table Text Block] Non-consolidated variable interest entities aggregated by principal business activity. Fair Value Disclosures [Abstract] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] 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 3 Fair Value, Inputs, Level 3 [Member] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Corporate equity securities Equity Securities [Member] Non-exchange-traded securities Non Exchange Traded Securities [Member] Non-exchange traded securities. Corporate debt securities Corporate Debt Securities [Member] CDOs and CLOs Collateralized Debt Obligations and Collateralized Loan Obligations [Member] Collateralized Debt Obligations and Collateralized Loan Obligations [Member] RMBS Residential Mortgage Backed Securities [Member] CMBS Commercial Mortgage Backed Securities [Member] Other ABS Other Asset Backed Securities [Member] Other asset-backed securities. Loans and other receivables Loans and Finance Receivables [Member] Equity options Equity Option [Member] Interest rate swaps Interest Rate Swap [Member] Cross currency swaps Cross Currency Interest Rate Contract [Member] Unfunded commitments Unfunded Commitments [Member] Unfunded Commitments [Member] Total return swaps Total Return Swap [Member] Interest Rate Swaps, Unfunded Commitments and Equity Options Interest Rate Swaps, Unfunded Commitments And Equity Options [Member] Interest Rate Swaps, Unfunded Commitments And Equity Options [Member] Investments at fair value Investments At Fair Value [Member] Investments At Fair Value [Member] Private equity securities Private Equity Securities [Member] Private equity securities. Securities purchased under agreements to resell Securities Purchased Under Agreements To Resell [Member] Securities Purchased Under Agreements To Resell [Member] Loans Loans [Member] Long-term debt Long-term Debt [Member] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Domain] Valuation Approach and Technique [Domain] Market approach Valuation, Market Approach [Member] Scenario analysis Scenario Analysis [Member] Scenario Analysis [Member] Discounted cash flows Valuation Technique, Discounted Cash Flow [Member] Volatility benchmarking Volatility Benchmarking [Member] Volatility Benchmarking [Member] Option model/default rate Valuation Technique, Option Pricing Model [Member] Measurement Input Type [Axis] Measurement Input Type [Axis] Measurement Input Type [Domain] Measurement Input Type [Domain] Price Measurement Input, Offered Price [Member] Estimated recovery percentage Measurement Input, Estimated Recovery Percentage [Member] Measurement Input, Estimated Recovery Percentage [Member] Volatility Measurement Input, Price Volatility [Member] Credit spread Measurement Input, Credit Spread [Member] Underlying stock price Measurement Input, Share Price [Member] Transaction level Measurement Input, Transaction Level [Member] Measurement Input, Transaction Level [Member] Constant prepayment rate Measurement Input, Prepayment Rate [Member] Constant default rate Measurement Input, Default Rate [Member] Loss severity Measurement Input, Loss Severity [Member] Discount rate/yield Measurement Input, Discount Rate [Member] Cumulative loss rate Measurement Input, Cumulative Loss Rate [Member] Measurement Input, Cumulative Loss Rate [Member] Revenue growth Measurement Input, Long-term Revenue Growth Rate [Member] Basis points upfront Measurement Input, Basis Points [Member] Measurement Input, Basis Points [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] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Weighted Average Weighted Average [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] Financial instruments owned, at fair value Financial Instruments, Owned, at Fair Value Excluding Investments at Net Asset Value Financial Instruments, Owned, at Fair Value Excluding Investments at Net Asset Value Debt securities, trading, measurement input Debt Securities, Trading, Measurement Input Derivative assets Derivative Asset Financial instruments sold, not yet purchased, at fair value Financial Instruments Sold, Not yet Purchased, at Fair Value Derivative liabilities Derivative Liability Financial instruments owned, measurement input Financial Instruments, Owned, Measurement Input Financial Instruments, Owned, Measurement Input Financial instruments owned, measurement input, term Financial Instruments, Owned, Measurement Input, Term Financial Instruments, Owned, Measurement Input, Term 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, measurement input Debt Instrument, Measurement Input Derivative liability, measurement input Derivative Liability, Measurement Input Long-term debt, measurement input Long-term Debt, Measurement Input Value of asset excluded from significant unobservable inputs Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Asset Exclusion Value Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Asset Exclusion Value Value of liability excluded from significant unobservable inputs Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Exclusion Value Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Exclusion Value Variable Interest Entities Variable Interest Entity Disclosure [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Fair Value and Related Number of Derivative Contracts Categorized by Type of Derivative Contract 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 [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 [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] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Deferred tax assets: Deferred Tax Assets, Net [Abstract] Compensation and benefits Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation Net operating loss Deferred Tax Assets, Operating Loss Carryforwards Long-term debt Deferred Tax Assets Long Term Debt Deferred Tax Assets Long Term Debt Accrued expenses and other Deferred Tax Assets Accrued Expenses And Other Deferred Tax Assets Accrued Expenses And Other Sub-total Deferred Tax Assets, Gross Valuation allowance Deferred Tax Assets, Valuation Allowance Total deferred tax assets Deferred Tax Assets, Net of Valuation Allowance Deferred tax liabilities: Deferred Tax Liabilities, Gross [Abstract] Amortization of intangibles Deferred Tax Liabilities, Intangible Assets Other Deferred Tax Liabilities, Other Total deferred tax liabilities Deferred Tax Liabilities, Net Net deferred tax asset, included in Other assets Deferred Tax Assets, Net Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Epic Gas Epic Gas [Member] Epic Gas [Member] Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Ownership percentage Equity Method Investment, Ownership Percentage Proceeds from sale of Epic Gas Proceeds from Sale of Equity Method Investments Gain on sale of Epic Gas Equity Method Investment, Realized Gain (Loss) on Disposal Our total equity balance Equity Method Investments Related Party Transactions [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Title of Individual [Axis] Title of Individual [Axis] Relationship to Entity [Domain] Relationship to Entity [Domain] Director Director [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Affiliated Entity Affiliated Entity [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Loans to and investments in related parties Loans and Leases Receivable, Related Parties Investment in related party Related Party Transaction, Investment Amount Related Party Transaction, Investment Amount Financial instruments owned: Financial Instruments, Owned, at Fair Value [Abstract] 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, Aggregated Difference Long-term debt and short-term borrowings Fair Value, Option, Aggregate Differences, Long-term And Short-Term Debt Instruments Fair Value, Option, Aggregate Differences, Long-term And Short-Term Debt Instruments 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 Current: Current Income Tax Expense (Benefit), Continuing Operations [Abstract] U.S. Federal Current Federal Tax Expense (Benefit) U.S. state and local Current State and Local Tax Expense (Benefit) Foreign Current Foreign Tax Expense (Benefit) Total current Current Income Tax Expense (Benefit) Deferred: Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] U.S. Federal Deferred Federal Income Tax Expense (Benefit) U.S. state and local Deferred State and Local Income Tax Expense (Benefit) Foreign Deferred Foreign Income Tax Expense (Benefit) Total deferred Deferred Income Tax Expense (Benefit) Total income tax expense Income Tax Expense (Benefit) Income Tax Examination [Table] Income Tax Examination [Table] Valuation Allowance by Deferred Tax Asset [Axis] Valuation Allowance by Deferred Tax Asset [Axis] Deferred Tax Asset [Domain] Deferred Tax Asset [Domain] Europe Europe [Member] Asia Asia [Member] Income Tax Examination [Line Items] Income Tax Examination [Line Items] Federal statutory income tax rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Unrecognized tax benefits that would impact effective tax rate in future Unrecognized Tax Benefits that Would Impact Effective Tax Rate Net interest expense related to unrecognized tax benefits Unrecognized Tax Benefits, Interest on Income Taxes Expense Accrued interest on unrecognized tax benefits Unrecognized Tax Benefits, Interest on Income Taxes Accrued Net deferred tax asset Operating loss carryforwards Operating Loss Carryforwards Deferred tax asset related to net operating losses Valuation allowance Decrease in unrecognized tax benefits is reasonably possible Decrease in Unrecognized Tax Benefits is Reasonably Possible Increase of provisional tax charge related to the Tax Act Tax Cuts And Jobs Act Of 2017, Measurement Period Adjustment, Provisional Income Tax Expense (Benefit) Tax Cuts And Jobs Act Of 2017, Measurement Period Adjustment, Provisional Income Tax Expense (Benefit) Provisional impact of the Tax Act Tax Cuts And Jobs Act Of 2017, Provisional Income Tax Expense (Benefit) Tax Cuts And Jobs Act Of 2017, Provisional Income Tax Expense (Benefit) Provisional impact of the Tax Act related to revaluation of deferred tax asset Tax Cuts And Jobs Act Of 2017, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense (Benefit) Tax Cuts And Jobs Act Of 2017, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense (Benefit) Accounting Policies [Abstract] Organization and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Revenue from Contract with Customer [Abstract] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Equities Equities [Member] Equities [Member] Fixed Income Fixed Income Services [Member] Fixed Income Services [Member] Investment banking - Advisory Investment Banking, Advisory [Member] Investment Banking, Advisory [Member] Investment banking - Underwriting Investment Banking, Underwriting [Member] Investment Banking, Underwriting [Member] Asset management Asset Management Services [Member] Asset Management Services [Member] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Americas Americas [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Investment Banking and Capital Markets Investment Banking And Capital Markets [Member] Investment Banking And Capital Markets Asset Management Asset Management Segment [Member] Asset Management Segment [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenue from contracts with customers Revenue from Contract with Customer, Excluding Assessed Tax Total assets Equity Method Investment, Summarized Financial Information, Assets Total liabilities Equity Method Investment, Summarized Financial Information, Liabilities Total equity Equity Method Investment, Summarized Financial Information, Equity Excluding Noncontrolling Interests Net gains (losses) Equity Method Investment, Summarized Financial Information, Net Income (Loss) Related Party Transactions Related Party Transactions Disclosure [Text Block] Schedule of Related Party Transactions Schedule of Related Party Transactions [Table Text Block] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] CLOs Collateralized Loan Obligations [Member] Consumer loan and other asset-backed vehicles Consumer Loan And Other Asset-Backed Vehicles [Member] Consumer Loan And Other Asset-Backed Vehicles [Member] Related party private equity vehicles Private Equity Vehicles [Member] Private equity vehicles. Other investment vehicles Other Investment Vehicles [Member] Other Investment Vehicles [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Nonconsolidated VIEs, assets carrying amount Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets Nonconsolidated VIEs, liabilities carrying amount Variable Interest Entity, Nonconsolidated, Carrying Amount, Liabilities Maximum Exposure to Loss Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount VIE Assets Variable Interest Entity Carrying Amount Of Assets Non Consolidated Vie Variable Interest Entity Carrying Amount Of Assets Non Consolidated Vie Condensed Financial Information Disclosure [Abstract] Condensed Cash Flow Statement [Table] Condensed Cash Flow Statement [Table] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Parent Company Parent Company [Member] Condensed Cash Flow Statements, Captions [Line Items] Condensed Cash Flow Statements, Captions [Line Items] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net earnings Net Income (Loss) Attributable to Parent Adjustments to reconcile net earnings to net cash provided by (used in) operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Amortization Depreciation, Depletion and Amortization Undistributed earnings of subsidiaries Undistributed Gain Loss Of Subsidiaries Undistributed Gain Loss Of Subsidiaries (Income) loss on loans to and investments in related parties Income On Loans To And Investments In Related Parties Income On Loans To And Investments In Related Parties Distributions received on investments in related parties Distributions Received On Investments In Related Parties Distributions Received On Investments In Related Parties Other adjustments Other Noncash Income (Expense) Net change in assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Financial instruments owned Increase (Decrease) in Financial Instruments Used in Operating Activities Other assets Increase (Decrease) in Other Operating Assets Financial instruments sold, not yet purchased Increase (Decrease) in Financial Instruments Sold, Not yet Purchased Accrued expenses and other liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Net cash provided by (used in) operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Investments in, advances to and subordinated notes receivable from subsidiaries Payments for (Proceeds from) Investments in, Advances to and Notes Receivable from Subsidiary Payments for (Proceeds from) Investments in, Advances to and Notes Receivable from Subsidiary Loans to and investments in related parties Proceeds from Collection of (Payments to Fund) Long-term Loans to Related Parties Cash received from contingent consideration Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Asset Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from short-term borrowings Proceeds from Short-term Debt Payments on short-term borrowings Repayments of Short-term Debt Proceeds from issuance of long-term debt, net of issuance costs Proceeds from Issuance of Senior Long-term Debt Repayment of long-term debt Repayments of Long-term Debt Distributions to Jefferies Financial Group Inc. Payments of Capital Distribution Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Net increase 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 Supplemental disclosures of cash flow information: Supplemental Cash Flow Information [Abstract] Cash paid during the period for: Cash Paid Received During Period [Abstract] Cash paid (received) during the period for: Interest Interest Paid, Excluding Capitalized Interest, Operating Activities Income taxes, net Income Taxes Paid, Net Compensation Related Costs [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Non-vested share-based awards Nonvested Share Awards [Member] Nonvested Share Awards [Member] Restricted cash awards Restricted Cash Awards [Member] Restricted Cash Awards [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Remaining Unamortized Amounts Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Weighted Average Vesting Period (in Years) Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Debt Disclosure [Abstract] Long-Term Debt Long-term Debt [Text Block] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Jefferies Financial Group Inc. Jefferies Financial Group Inc. [Member] Jefferies Financial Group Inc. [Member] Berkadia Berkadia Commercial Mortgage, LLC [Member] Berkadia Commercial Mortgage, LLC [Member] Capital contribution from Jefferies Proceeds from Contributions from Parent Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Cash and securities segregated and on deposit for regulatory purposes with clearing and depository organizations Cash And Securities Segregated And On Deposit For Regulatory Purposes With Clearing And Depository Organizations Cash And Securities Segregated And On Deposit For Regulatory Purposes With Clearing And Depository Organizations Total cash, cash equivalents and restricted cash Brokers and Dealers [Abstract] Schedule of Net Capital, Adjusted and Excess Net Capital Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block] Amount of restricted net assets Amount of Restricted Net Assets for Consolidated and Unconsolidated Subsidiaries Revenue related to performance obligations satisfied Contract With Customer, Performance Obligation Satisfied Contract With Customer, Performance Obligation Satisfied Revenue associated with distribution services, a portion of which related to prior periods Contract with Customer, Performance Obligation Satisfied in Previous Period Receivables related to revenue from contracts with customers Contract with Customer, Asset, Net Deferred revenue Contract with Customer, Liability, Current Deferred revenue, revenue recognized Contract with Customer, Liability, Revenue Recognized Capitalized contract cost Capitalized Contract Cost, Net Expenses related to capitalized costs to fulfill a contract Capitalized Contract Cost, Amortization Schedule of Goodwill [Table] Schedule of Goodwill [Table] Goodwill [Line Items] Goodwill [Line Items] Goodwill Goodwill Aggregate amortization expense Amortization of Intangible Assets Compensation Plans Compensation Related Costs, General [Text Block] Retirement Benefits [Abstract] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Retirement Plan Sponsor Location [Axis] Retirement Plan Sponsor Location [Axis] Retirement Plan Sponsor Location [Domain] Retirement Plan Sponsor Location [Domain] Domestic Plan Domestic Plan [Member] United States UNITED STATES Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] 2020 Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months 2021 Defined Benefit Plan, Expected Future Benefit Payment, Year Two 2022 Defined Benefit Plan, Expected Future Benefit Payment, Year Three 2023 Defined Benefit Plan, Expected Future Benefit Payment, Year Four 2024 Defined Benefit Plan, Expected Future Benefit Payment, Year Five 2025 through 2029 Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter 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 Swaption [Member] Derivative [Line Items] Derivative [Line Items] Notional amount Derivative Asset, Notional Amount Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent event Subsequent Event [Member] Restricted cash awards Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] Year Ended November 30, 2019 Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost Recognized, Remainder Of Year Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost Recognized, Remainder Of Year Year Ended November 30, 2020 Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost Recognized in Year Two Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost Recognized in Year Two Year Ended November 30, 2021 Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost Recognized in Year Three Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost Recognized in Year Three Thereafter Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost Recognized Thereafter Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost Recognized Thereafter Total Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost Components of Provision for Income Tax Expense Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of Components of Income before Income Tax Expense Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block] Reconciliation of Effective Tax Rate to U.S. Federal Statutory Income Tax Rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Roll Forward of Gross Unrecognized Tax Benefits Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] Significant Components of Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Earliest Tax Year Subject to Examination in the Major Tax Jurisdictions in which the Company Operates Summary of Income Tax Examinations [Table Text Block] Domestic Plan Service cost Defined Benefit Plan, Service Cost Interest cost on projected benefit obligation Defined Benefit Plan, Interest Cost Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Net amortization Defined Benefit Plan, Amortization of Gain (Loss) Settlement losses Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement Net periodic pension cost Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Summary of Selected Financial Information Equity Method Investments [Table Text Block] Statement of Comprehensive Income [Abstract] Statement [Table] Statement [Table] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Pension Plan Pension Plan [Member] German Plan Foreign Plan [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Currency translation and other adjustments Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Changes in instrument specific credit risk Accumulated Changes In Instrument Specific Credit Risk Attributable To Parent [Member] Accumulated Changes In Instrument Specific Credit Risk Attributable To Parent [Member] Cash flow hedges Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] Minimum pension liability adjustments Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Statement [Line Items] Statement [Line Items] Impact of certain discrete items related to non-U.S. subsidiaries planning for the Tax Act Adjustment related to foreign currency gains reclassified to other revenues Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax Changes in instrument specific credit risk, tax benefits (expenses) Other Comprehensive Income (Loss), Changes in Instrument Specific Credit Risk, Tax Other Comprehensive Income (Loss), Changes in Instrument Specific Credit Risk, Tax Changes in instrument specific credit risk reclassified to Principal transactions revenues Other Comprehensive Income (Loss) Changes In Instrument Specific Credit Risk Reclassified Gain (Loss) Other Comprehensive Income (Loss) Changes In Instrument Specific Credit Risk Reclassified To Earnings, Tax Changes in instrument specific credit risk reclassified to Principal transactions revenues, tax Other Comprehensive Income (Loss) Changes In Instrument Specific Credit Risk Reclassified To Earnings, Tax Other Comprehensive Income (Loss) Changes In Instrument Specific Credit Risk Reclassified To Earnings, Tax Reclassification amount related to the Tax Act Tax Cuts And Jobs Act Of 2017 Reclassification From Aoci To Retained Earnings Tax Effect Amount of increase (decrease) in accumulated other comprehensive income (AOCI) for reclassification to retained earnings of tax effect from remeasurement of deferred tax pursuant to Tax Cuts and Jobs Act of 2017. Cash flow hedges, tax benefits (expenses) Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Cash flow hedges reclassification amount Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Minimum pension liability adjustments, tax benefits (expenses) Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax Pension losses reclassification amount Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax Pension losses reclassification amount, tax Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax Minimum pension liability adjustments, net of tax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Unrealized gain on available-for-sale securities, tax expense Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax Fair value of OTC derivatives assets, Counterparty credit quality, A- or higher Fair Value Of Over Counter Derivatives Assets Counterparty Credit QualityA Or Higher Fair Value Of Over Counter Derivatives Assets Counterparty Credit QualityA Or Higher Fair value of OTC derivatives assets, Counterparty credit quality, BBB- to BBB+ Fair Value Of Over Counter Derivatives Assets Counterparty Credit Quality Bbb To Bbb Fair value of OTC derivatives assets, counterparty credit quality BBB- to BBB. Fair value of OTC derivatives assets, Counterparty credit quality, BB+ or lower Fair Value Of Over Counter Derivatives Assets Counterparty Credit Quality Bb or Lower Fair value of OTC derivatives assets, counterparty credit quality BB or lower. Fair value of OTC derivatives assets, Counterparty credit quality, 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 Financial instruments owned Otc Derivative Assets Included In Financial Instruments Owned OTC Derivative Assets Included In Financial Instruments Owned. Year ending November 30, 2020 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Year ending November 30, 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Two Year ending November 30, 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Three Year ending November 30, 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Four Year ending November 30, 2024 Finite-Lived Intangible Assets, Amortization Expense, Year Five Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Net Capital Requirements Brokers and Dealers Disclosure [Text Block] Banking and Thrift [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] 31-90 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 Obligation To Return Securities Received As Collateral Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Amount Offset Against Collateral Total Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement Percentage of profits received from joint venture Percentage Of Profits Received From Joint Venture Percentage Of Profits Received From Joint Venture Purchase commitment amount Purchase Commitment Amount Purchase Commitment Amount Cash distribution from equity method investment Proceeds from Equity Method Investment, Distribution Schedule of Gain (Loss) on Securities [Table] Schedule of Gain (Loss) on Securities [Table] Loans Loan commitments Loan Commitments [Member] Loan commitments. Long-term debt Short-term borrowings Short-term Debt [Member] Gain (Loss) on Securities [Line Items] Gain (Loss) on Securities [Line Items] Financial instruments owned: Loans and other receivables Fair Value, Option, Credit Risk, Gains (Losses) on Assets Financial instruments sold, not yet purchased, Long-term debt and Short-term borrowings Financial Instruments Sold, Not yet Purchased, at Fair Value [Abstract] Changes in instrument specific credit risk Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Reclassification Adjustment from AOCI for Derecognition, after Tax Other changes in fair value Fair Value, Option, Changes in Fair Value, Gain (Loss) Corporate equity securities Corporate debt securities CDOs and CLOs Municipal securities Municipal Bonds [Member] RMBS CMBS Other ABS Loans and other receivables Investments at fair value Investments [Member] Securities purchased under agreements to resell Loans Net derivatives Derivative Financial Instruments, Liabilities [Member] Other secured financings Other Secured Financings At Fair Value [Member] Other Secured Financings At Fair Value [Member] 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 Changes in unrealized gains/(losses) included in earnings for instruments still held Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Changes in unrealized gains/ (losses) included in other comprehensive income for instruments still held Fair Value, Assets Measured On Recurring Basis, Change In Unrealized Gain (Loss) Included In Other Comprehensive Income Fair Value, Assets Measured On Recurring Basis, Change In Unrealized Gain (Loss) Included In Other Comprehensive Income 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 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 Changes in unrealized gains/ (losses) included in earnings for instruments still held Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss) Changes in unrealized gains/ (losses) included in other comprehensive income for 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 Segment Reporting [Abstract] Number of reportable segments Number of Reportable Segments JCP Fund V JCP Funds [Member] JCP Funds [Member] Investment amount Total committed equity capitalization Commitments Under Equity Capitalization Of Joint Venture Entity Commitments under equity capitalization of joint venture entity. Unfunded portion of equity commitment to subsidiary Equity Commitment To Joint Venture Unfunded Portion Equity commitment to joint venture unfunded portion. Percent of financial information presented Equity Method Investment, Percent of Financial Information Presented Equity Method Investment, Percent of Financial Information Presented U.S. Income (Loss) from Continuing Operations before Income Taxes, Domestic Non-U.S. Income (Loss) from Continuing Operations before Income Taxes, Foreign Earnings before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Schedule I (PARENT COMPANY ONLY) Condensed Financial Information of Parent Company Only Disclosure [Text Block] Net gains (losses) from our investments in JCP Fund V Total assets Total liabilities Total partners’ capital Equity Method Investment Summarized Financial Information, Equity Net increase (decrease) in net assets resulting from operations Equity Method Investment, Increase (Decrease) in Assets Equity Method Investment, Increase (Decrease) in Assets Fair Value Disclosures Fair Value Disclosures [Text Block] Loss Contingencies [Table] Loss Contingencies [Table] Jefferies Capital Partners LLC Jefferies Capital Partners Llc [Member] Jefferies capital partners, LLC. Other Investments Investments, Other [Member] Investments, Other [Member] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Standby Letters of Credit Standby Letters of Credit [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Outstanding equity commitments Equity Commitments Committed equity capitalization. Loan commitments outstanding to clients Loan Commitments Outstanding Loan commitments outstanding to clients. Future minimum rentals due from non-cancelable sublease Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals Rental expense, net Operating Leases, Rent Expense, Net Fair value of derivative contracts approximated deemed to meet the definition of a guarantee Guarantee Obligations Maximum Exposure Fair Value Guarantee obligations maximum exposure fair value. Letters of credit commitments Standby Letters Of Credit Commitments Standby Letters Of Credit Commitments Letters of credit commitments expiration period Standby Letters of Credit Expiration Period Standby Letters of Credit Expiration Period Quarterly Financial Information Disclosure [Abstract] Selected Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Schedule of Commitments and Contingencies Contractual Obligation, Fiscal Year Maturity Schedule [Table Text Block] Schedule of Future Minimum Lease Commitments under Leases Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Schedule of Guarantees Schedule of Guarantor Obligations [Table Text Block] Organization And Basis Of Presentation [Table] Organization And Basis Of Presentation [Table] Organization And Basis Of Presentation [Table] Change in Accounting Estimate by Type [Axis] Change in Accounting Estimate by Type [Axis] Change in Accounting Estimate, Type [Domain] Change in Accounting Estimate, Type [Domain] Reclassified Presentation of Certain Other Fees Reclassified Presentation Of Certain Other Fees [Member] Reclassified Presentation Of Certain Other Fees [Member] Commissions and other fees Commissions And Other Fees [Member] Commissions And Other Fees [Member] Berkadia Commercial Mortgage, LLC Organization And Basis Of Presentation [Line Items] Organization And Basis Of Presentation [Line Items] Organization And Basis Of Presentation [Line Items] Number of reportable segments Increase of commissions and other fee Reducing of other revenues Other Income Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Structured notes Structured Notes [Member] Structured Notes [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Unsecured long-term debt Unsecured Debt [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Maximum amount payable under guarantees Guarantor Obligations, Maximum Exposure, Undiscounted Long-term debt Long-term Debt Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Profit sharing plan Profit Sharing Plan [Member] Profit Sharing Plan [Member] Deferred Compensation Plan Deferred Compensation Plan [Member] Deferred Compensation Plan [Member] Restricted cash awards Restricted stock and RSUs Restricted Stock and Restricted Stock Units [Member] Restricted Stock and Restricted Stock Units [Member] Total compensation cost Allocated Share-based Compensation Expense Restricted cash awards Deferred Compensation Arrangement with Individual, Compensation Expense Jefferies Finance Jefferies Finance Llc [Member] Jefferies Finance LLC. Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Promissory Note Promissory Note [Member] Promissory Note [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other Assets Other Assets [Member] Accounts expenses and other liabilities Accounts Payable and Accrued Liabilities [Member] Payables to customers Payables To Customers [Member] Payables To Customers [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Committed advances Committed Advances [Member] Committed Advances [Member] Equity commitment Equity Commitment, Amount Equity Commitment, Amount Funded portion of equity commitment to subsidiary Equity Commitment To Joint Venture Funded Portion Equity commitment to joint venture funded portion. Extension period Line Of Credit Extension Period Line of credit extension period. Termination notice period Line Of Credit Termination Notice Period Line of credit termination notice period. Committed line of credit facility amount Line Of Credit Facility Commitment Under Joint Venture Line of credit facility commitment under joint venture. Funded portion of loan commitment Loan Commitment To Joint Venture Funded Portion Loan Commitment To Joint Venture Funded Portion Loan commitment Aggregate Loan Commitment Aggregate loan commitment to joint venture. Receivables under service agreement Due from Related Parties Payables under service agreement Due to Related Parties Payables to brokers, dealers and clearing organizations Payables to Broker-Dealers and Clearing Organizations Debt principal amount Debt Instrument, Face Amount Interest expense Interest Expense Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table] Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table] Investment Redemption Prior Written Notice Period [Axis] Investment Redemption Prior Written Notice Period [Axis] Investment Redemption Prior Written Notice Period [Axis] Investment Redemption Prior Written Notice Period [Domain] Investment Redemption Prior Written Notice Period [Domain] [Domain] for Investment Redemption Prior Written Notice Period [Axis] 60 Days Prior Written Notice 60 Days Prior Written Notice [Member] 60 Days Prior Written Notice [Member] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Equity Long/Short Hedge Funds Hedge Funds, Equity Long (Short) [Member] Equity Funds Private 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] 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 Alternative Investment Unfunded Commitments Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments Percentage of investments in liquidation Percentage of Investment at Fair Value in Liquidation Percentage of Investment at Fair Value in Liquidation Investments redemption restriction period Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Redemption Restriction, Period in Effect Percentage of investments redeemable Redeemable Investments Investments redeemable within 60-90 days Notice period redemption of investment prior written notice 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. Estimated period for the liquidation of the underlying assets, minimum Expected Period For Liquidation Of Underlying Assets Minimum Expected Period For Liquidation Of Underlying Assets Minimum Estimated period for the liquidation of the underlying assets, maximum Expected Period For Liquidation Of Underlying Assets Maximum Expected Period For Liquidation Of Underlying Assets Maximum Jefferies Capital Partners V L.P. Jefferies Capital Partners V L.P [Member] Jefferies Capital Partners V L.P [Member] SBI USA Fund L.P. SBI USA Fund L.P. [Member] SBI USA Fund L.P. [Member] Schedule of Short-Term Borrowings Schedule of Short-term Debt [Table Text Block] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Derivatives designated as accounting hedges: Designated as Hedging Instrument [Member] Derivatives not designated as accounting hedges: Not Designated as Hedging Instrument [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] 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] Exchange-traded Exchange Traded Options [Member] Cleared OTC Otc Cleared [Member] OTC Cleared [Member] Bilateral OTC Bilateral Otc [Member] Bilateral OTC [Member] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Fair Value, Assets Derivative Asset, Fair Value, Gross Asset Number of Contracts, Assets Derivative Asset, Number of Instruments Held Fair Value, Liabilities Derivative Liability, Fair Value, Gross Liability Number of Contracts, Liabilities Derivative Liability, Number of Instruments Held Amounts offset in the Consolidated Statements of Financial Condition, Assets Derivative Asset, Collateral, Obligation to Return Cash, Offset Amounts offset in the Consolidated Statements of Financial Condition, Liabilities Derivative Liability, Collateral, Right to Reclaim Cash, Offset Net amounts per Consolidated Statements of Financial Condition, Assets Net amounts per Consolidated Statements of Financial Condition, Liabilities New Accounting Pronouncements and Changes in Accounting Principles [Abstract] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] ASU 2016-02 Accounting Standards Update 2016-02 [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Recognition of operating lease, ROU asset Operating Lease, Right-of-Use Asset Recognition of operating lease, liabilities Operating Lease, Liability Transferred assets Assets Transferred Due To Securitization Assets transferred due to securitization activities in which the Company had continuing involvement. Proceeds on new securitizations Proceeds On New Securitizations Proceeds On New Securitizations Cash flows received on retained interests Cash Flows Between Transferor and Transferee, Proceeds from New Transfers Financial Assets and Liabilities Accounted for at Fair Value on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Investments Measured at Fair Value Based on Net Asset Value Per Share Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table Text Block] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Quantitative Information about Significant Unobservable Inputs Used in Level 3 Fair Value Measurements Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Summary of Gains (Losses) Due to Changes in Instrument Specific Credit Risk and Summary of Contractual Principal Exceeds Fair Value for Loans and Other Receivables Fair Value Option, Disclosures [Table Text Block] Assets and Liabilities Measured at Fair Value on a Non-recurring Basis Fair Value Measurements, Nonrecurring [Table Text Block] Jefferies LoanCore Jefferies Loan Core Llc [Member] Jefferies loan core LLC. Proceeds from sale of Jefferies LoanCore Period entitled to additional cash consideration Equity Method Investment Sale, Period Entitled To Additional Cash Consideration Equity Method Investment Sale, Period Entitled To Additional Cash Consideration Net earnings Interest income and fees related to master repurchase agreement Interest Income And Fees Related To Master Repurchase Agreement Interest Income And Fees Related To Master Repurchase Agreement Short-Term Borrowings Short-term Debt [Text Block] Change in projected benefit obligation: Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Projected benefit obligation, beginning of period Defined Benefit Plan, Benefit Obligation Service cost Interest cost Actuarial (gains)/losses Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) Administrative expenses paid Defined Benefit Plan Administrative Expenses Paid Defined Benefit Plan Administrative Expenses Paid. Benefits paid Defined Benefit Plan, Benefit Obligation, Benefits Paid Settlements Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement Projected benefit obligation, end of period Change in plan assets: Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Fair value of assets, beginning of period Defined Benefit Plan, Plan Assets, Amount Benefits paid Defined Benefit Plan, Plan Assets, Benefits Paid Administrative expenses paid Actual return on plan assets Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) Contributions Defined Benefit Plan, Plan Assets, Contributions by Employer Settlements Defined Benefit Plan, Plan Assets, Payment for Settlement Fair value of assets, end of period Funded status at end of period Defined Benefit Plan, Funded (Unfunded) Status of Plan Income tax expense Investments Equity Method Investments and Joint Ventures Disclosure [Text Block] Goodwill [Roll Forward] Goodwill [Roll Forward] Balance, at beginning of period Translation adjustments Goodwill, Foreign Currency Translation Gain (Loss) Goodwill acquired during the period Goodwill, Acquired During Period Balance, at end of period Accumulated goodwill impairments Goodwill, Impaired, Accumulated Impairment Loss Goodwill, gross Goodwill, Gross Amounts recognized in Other comprehensive income: Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract] Net (gain) loss arising during the period Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax Amortization of net loss Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax Settlements during the period Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax Total losses recognized in Other comprehensive income Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax Net losses/(gains) recognized in net periodic benefit cost and Other comprehensive income Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax Hedging relationship effective percentage Derivative, Hedging Relationship Effective Percentage Derivative, Hedging Relationship Effective Percentage Securities Borrowed Type [Axis] Securities Borrowed Type [Axis] Securities Borrowed Type [Axis] Securities Borrowed Type [Domain] Securities Borrowed Type [Domain] [Domain] for Securities Borrowed Type [Axis] Securities Received as Collateral Securities Received As Collateral [Member] Securities Received As Collateral [Member] Securities Loaned Type [Axis] Securities Loaned Type [Axis] Securities Loaned Type [Axis] Securities Loaned Type [Domain] Securities Loaned Type [Domain] [Domain] for Securities Loaned Type [Axis] Obligation to Return Securities Received as Collateral Obligation To Return Securities Received As Collateral [Member] Obligation To Return Securities Received As Collateral [Member] Securities borrowing arrangements Securities Borrowed [Abstract] Gross Amounts Securities Borrowed, Gross Netting in Consolidated Statement of Financial Condition Securities Borrowed, Liability Net Amounts in Consolidated Statement 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, Amount Offset Against Collateral Reverse repurchase agreements Offsetting Securities Purchased under Agreements to Resell [Abstract] Gross Amounts Securities Purchased under Agreements to Resell, Gross Netting in Consolidated Statement of Financial Condition Securities Purchased under Agreements to Resell, Liability Net Amounts in Consolidated Statement of Financial Condition Securities Purchased under Agreements to Resell Additional Amounts Available for Setoff Securities Purchased under Agreements to Resell, Not Offset, Policy Election Deduction Available Collateral Securities Purchased under Agreements to Resell, Fair Value of Collateral Net Amount Securities Purchased under Agreements to Resell, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election Securities lending arrangements Securities Loaned [Abstract] Gross Amounts Securities Loaned, Gross Netting in Consolidated Statement of Financial Condition Securities Loaned, Asset Net Amounts in Consolidated Statement 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, Amount Offset Against Collateral Repurchase agreements Offsetting Securities Sold under Agreements to Repurchase [Abstract] Gross Amounts Securities Sold under Agreements to Repurchase, Gross Netting in Consolidated Statement of Financial Condition Securities Sold under Agreements to Repurchase, Asset Net Amounts in Consolidated Statement of Financial Condition Securities Sold under Agreements to Repurchase Additional Amounts Available for Setoff Securities Sold under Agreements to Repurchase, Not Offset, Policy Election Deduction Available Collateral Securities Sold under Agreements to Repurchase, Fair Value of Collateral Net Amount Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral Securities borrowing arrangements Collateralized Financing Transactions Securities Borrowing Arrangements Collateralized Financing Transactions Securities Borrowing Arrangements Securities borrowing arrangements, collateral Collateralized Financing Transactions Securities Borrowing Arrangements Collateral Collateralized Financing Transactions Securities Borrowing Arrangements Securities Collateral Received Securities borrowing arrangements, repurchase agreements Collateralized Financing Transactions Securities Borrowing Arrangements Repurchase Agreements Collateralized Financing Transactions Securities Borrowing Arrangements Repurchase Agreements Securities borrowing arrangements, repurchase agreements, pledged securities collateral Collateralized Financing Transactions Securities Borrowing Arrangements Pledged Securities Collateral Collateralized Financing Transactions Securities Borrowing Arrangements Pledged Securities Collateral Cash Cash [Member] Financial instruments owned Financial Instruments Owned [Member] Financial Instruments Owned [Member] Securities purchased under agreements to resell Securities Purchased Under Agreement [Member] Securities Purchased Under Agreement [Member] Other secured financings Other Secured Financings [Member] Other Secured Financings [Member] Other liabilities Other Liabilities [Member] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Secured Funding Vehicles Secured Funding Vehicles [Member] Secured Funding Vehicles [Member] Other Other Activity [Member] Other activity. Total assets Variable Interest Entity, Consolidated, Carrying Amount, Assets Total liabilities Variable Interest Entity, Consolidated, Carrying Amount, Liabilities VIE liabilities, eliminated in consolidation Variable Interest Entity, Consolidated, Carrying Amount, Liabilities, Eliminated In Consolidation Variable Interest Entity, Consolidated, Carrying Amount, Liabilities, Eliminated In Consolidation Schedule of Components of Compensation Cost Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Schedule of Remaining Unamortized Amounts Related to Certain Compensation Plans Schedule Of Share Based Compensation Allocation Of Period Costs And Amortization Period Table [Table Text Block] Schedule Of Share Based Compensation Allocation Of Period Costs And Amortization Period Table [Table Text Block] Net Capital Requirements [Table] Net Capital Requirements [Table] Net Capital Requirements [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Jefferies LLC Jefferies [Member] A registered broker dealer under the Securities and Exchange act of 1934 and a wholly owned subsidiary of the Parent (Jefferies). 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 Corporate equity securities Corporate debt securities Mortgage-backed and asset-backed securities Mortgage and Asset-Backed Securities [Member] Mortgage and Asset-Backed Securities [Member] U.S. government and federal agency securities US Government Corporations and Agencies Securities [Member] Municipal securities Sovereign obligations Sovereign Debt [Member] Schedule Of Securitization Vehicles [Table] Schedule Of Securitization Vehicles [Table] Schedule of Securitization Vehicles. U.S. government agency RMBS Us Government Agency Issued Rmbs [Member] Us Government Agency Issued Rmbs [Member] U.S. government agency CMBS Us Government Agency Issued Cmbs [Member] Us Government Agency Issued Cmbs [Member] Consumer and other loans Other Debt Obligations [Member] Securitization Vehicles [Line Items] Securitization Vehicles [Line Items] Securitization vehicles. Total RMBS securitization assets Rmbs Securitization Assets Represents unpaid principal amount of assets in residential mortgage backed securitization vehicles at the balance sheet date. Total CMBS securitization assets Cmbs Securitization Assets Represents unpaid principal amount of assets in commercial mortgage backed securitization vehicles at the balance sheet date. Total Collateralized loan obligations Collateralized Loan Obligations Securitization Assets Collateralized Loan Obligations Securitization Assets Consumer and other loans Other Securitization Assets Other Securitization Assets Retained Interests Retained Interest, Fair Value Disclosure Accounting Developments New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Condensed Balance Sheet Statement [Table] Condensed Balance Sheet Statement [Table] Condensed Balance Sheet Statements, Captions [Line Items] Condensed Balance Sheet Statements, Captions [Line Items] ASSETS Assets [Abstract] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Cash and securities segregated and on deposited for regulatory purposes or deposited with clearing and depository organizations Cash and Securities Segregated under Federal and Other Regulations Financial instruments owned, at fair value Financial Instruments, Owned, at Fair Value Investment in subsidiaries Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Advances to subsidiaries Advances to Affiliate Subordinated notes receivable Accounts and Notes Receivable, Net Other assets Other Assets Total assets Assets LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Short-term borrowings Short-term Debt Accrued expenses and other liabilities Accounts Payable and Accrued Liabilities Total liabilities Liabilities EQUITY Equity [Abstract] Member’s paid-in capital Additional Paid in Capital, Common Stock Accumulated other comprehensive income (loss): Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Currency translation adjustments Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax Changes in instrument specific credit risk Accumulated Other Comprehensive Income (Loss), Changes in Instrument Specific Credit Risk, Net of Tax Accumulated Other Comprehensive Income (Loss), Changes in Instrument Specific Credit Risk, Net of Tax Cash flow hedges Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax Additional minimum pension liability Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax Available-for-sale securities Accumulated Other Comprehensive Income (Loss), Debt Securities, Available-for-sale, Adjustment, after Tax Total accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Total Jefferies Group LLC member’s equity Members Common Stockholders Equity Members Common Stockholders Equity Total liabilities and equity Liabilities Equity And Members Equity Stockholders Equity Liabilities Equity And Members Equity Stockholders Equity Schedule of Collateralized Financing Transactions Schedule of Collateralized Financing Transactions [Table Text Block] Schedule of Collateralized Financing Transactions [Table Text Block] Offsetting Assets Offsetting Assets [Table Text Block] Offsetting Liabilities Offsetting Liabilities [Table Text Block] Income Statement [Abstract] Investment banking Investment Banking [Member] Investment Banking [Member] Revenues: Revenues [Abstract] Principal transactions Principal Transactions Revenue, Net Asset management fees and revenues Asset Management Fees And Revenues From Profit Sharing Agreement Asset Management Fees And Revenues From Profit Sharing Agreement Interest Interest Income, Operating Other Total revenues Revenues Interest expense Net revenues Revenues, Net of Interest Expense Non-interest expenses: Noninterest Expense [Abstract] Compensation and benefits Labor and Related Expense Non-compensation expenses: Non Labor and Related Expense [Abstract] Non Labor and Related Expense [Abstract] Floor brokerage and clearing fees Floor Brokerage, Exchange and Clearance Fees Technology and communications Communications and Information Technology Occupancy and equipment rental Occupancy, Net Business development Business Development Professional services Professional Fees Underwriting costs Underwriting Costs Underwriting Costs Other Other Expenses Total non-compensation expenses Non Compensation Expenses Non Compensation Expenses Total non-interest expenses