Commitments and Contingencies Disclosure [Abstract] Commitments, Contingencies and Guarantees Commitments Contingencies and Guarantees [Text Block] Segment Reporting [Abstract] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Americas Americas [Member] Europe Europe [Member] Asia Asia [Member] Revenue from External Customer [Line Items] Revenue from External Customer [Line Items] Revenues: Revenues [Abstract] Net revenues Revenues, Net of Interest Expense Debt Disclosure [Abstract] 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 Notes Payable to Banks [Member] Secured revolving loan facilities Secured Debt [Member] Line of credit Line of Credit [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Secured revolving loan facilities Loan Facility [Member] Loan Facility [Member] Floating rate puttable notes Puttable Notes [Member] Puttable Notes [Member] Intraday Credit Facility Intraday Credit Facility [Member] Intraday Credit Facility [Member] Equity-linked notes Equity-linked Notes [Member] Equity-linked Notes [Member] Equity-Linked Notes Matured On July 18, 2017 Equity-Linked Notes Matured On July 18, 2017 [Member] Equity-Linked Notes Matured On July 18, 2017 [Member] Equity-Linked Notes Matured On September 20, 2017 Equity-Linked Notes Matured On September 20, 2017 [Member] Equity-Linked Notes Matured On September 20, 2017 [Member] First Secured Revolving Loan Facility First Secured Revolving Loan Facility [Member] First Secured Revolving Loan Facility [Member] Second Secured Revolving Loan Facility Second Secured Revolving Loan Facility [Member] Second Secured Revolving Loan Facility [Member] Demand Loan Facility Demand Loan Facility [Member] Demand Loan Facility [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Federal funds effective rate Federal Funds Effective Swap Rate [Member] LIBOR London Interbank Offered Rate (LIBOR) [Member] Short-term Debt [Line Items] Short-term Debt [Line Items] Short-term borrowings (includes $4,281 and $0 at fair value at August 31, 2017 and November 30, 2016, respectively) Short-term Debt Interest rate on short-term borrowings outstanding Short-term Debt, Weighted Average Interest Rate Average daily short-term borrowings Short-term Debt, Average Outstanding Amount Debt principal amount Debt Instrument, Face Amount Credit facility maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Related Party Transactions [Abstract] Summary of Interest Income, Other Revenues and Investment Income Attributable to Related Party Private Equity Funds Interest and Other Income [Table Text Block] Schedule of related party transactions Schedule of Related Party Transactions [Table Text Block] Fair Value Disclosures [Abstract] 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] 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 [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 [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 and Summary of Contractual Principal Exceeds Fair Value for Loans and Other Receivables Fair Value, Option, Quantitative Disclosures [Table Text Block] 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 [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 3 Fair Value, Inputs, Level 3 [Member] Security Owned and Sold, Not yet Purchased, at Fair Value [Axis] Security Owned and Sold, Not yet Purchased, at Fair Value [Axis] Security Owned and Sold, Not yet Purchased Fair Value, Security Name [Domain] Security Owned and Sold, Not yet Purchased Fair Value, Security Name [Domain] Financial instruments owned Financial Instruments Owned [Member] Financial Instruments Owned [Member] Financial Instruments Sold, Not Yet Purchased Financial Instruments Sold, Not Yet Purchased [Member] Financial Instruments Sold, Not Yet Purchased [Member] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Corporate equity securities Equity Securities [Member] 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] Investments at fair value Investments [Member] Loans Loans [Member] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Derivatives Derivative [Member] Eligible Item or Group for Fair Value Option [Axis] Financial Instrument [Axis] Fair Value, Option, Eligible Item or Group [Domain] Financial Instruments [Domain] Non-exchange-traded securities Non Exchange Traded Securities [Member] Non-exchange traded securities. Private equity securities Private Equity Securities [Member] Private equity securities. Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Equity swaps Equity Swap [Member] Equity options Equity Option [Member] Unfunded commitments Unfunded Commitments [Member] Unfunded Commitments [Member] Variable funding note swaps Variable Funding Note Swaps [Member] Variable Funding Note Swaps [Member] Credit default swaps Credit Default Swap [Member] Interest rate swaps Interest Rate Swap [Member] Valuation Technique [Axis] Valuation Technique [Axis] Valuation Technique [Domain] Valuation Technique [Domain] Market approach Market Approach Valuation Technique [Member] Comparable pricing Comparable Pricing Valuation Technique [Member] Comparable Pricing Valuation Technique [Member] Convertible bond model Convertible Bond Model [Member] Convertible Bond Model [Member] Discounted cash flows Discounted Cash Flow Approach [Member] Discounted Cash Flow Approach [Member] Present value Present Value [Member] Present Value [Member] Scenario analysis Scenario Analysis [Member] Scenario Analysis [Member] Option model/default rate Option Model/Default Rate Valuation Technique [Member] Option Model/Default Rate Valuation Technique [Member] Option model Valuation Technique Option Model [Member] Valuation Technique Option Model [Member] Default rate Default Rate Valuation Technique [Member] Default Rate Valuation Technique [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] Instruments owned, fair value Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Instruments sold, not yet purchased, fair value Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value Significant Unobservable Input(s), Price Fair Value Inputs, Price Fair Value Inputs, Price Significant Unobservable Input(s), Underlying stock price (in dollars per share) Share Price Significant Unobservable Input(s), Comparable asset price Fair Value Inputs, Comparable Asset Price Fair Value Inputs, Comparable Asset Price Significant Unobservable Input(s), Volatility Fair Value Assumptions, Expected Volatility Rate Significant Unobservable Input(s), Discount rate/yield Cash Flow Discount Rate Cash Flow Discount Rate Significant Unobservable Input(s), Estimated recovery percentage Fair Value Assumptions Estimated Recovery Percentage Fair value assumptions estimated recovery percentage. Significant Unobservable Input(s), Cumulative loss rate Cumulative Loss Rate Cumulative Loss Rate Significant Unobservable Input(s), Duration (years) Fair Value Inputs, Duration Fair Value Inputs, Duration Significant Unobservable Input(s), EBITDA multiple Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple Significant Unobservable Input(s), Constant prepayment rate Fair Value Inputs, Prepayment Rate Significant Unobservable Input(s), Constant default rate / Credit spread Fair Value Inputs, Entity Credit Risk Significant Unobservable Input(s), Loss severity Fair Value Inputs, Loss Severity Significant Unobservable Input(s), Average silver production (tons per day) Fair Value Inputs, Average Silver Production Fair Value Inputs, Average Silver Production Significant Unobservable Input(s), Yield Valuation Yield Estimated yield in a DCF applied in estimating the fair value of financial assets and liabilities. Significant Unobservable Input(s), Transaction level (in dollars per share) Transaction Level Price Per Share Transaction Level Price Per Share Significant Unobservable Input(s), Default probability Fair Value Inputs, Probability of Default 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 Derivative Instruments and Hedging Activities Disclosure [Abstract] Fair value of derivative instruments in a liability position Derivative, Net Liability Position, Aggregate Fair Value Collateral posted for derivative instruments in a liability position Collateral Already Posted, Aggregate Fair Value Additional collateral required for derivative instruments in a liability position Additional Collateral, Aggregate Fair Value Segment Reporting Segment Reporting Disclosure [Text Block] 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] Compensation Plans [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 Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Capital Markets Capital Markets [Member] Capital markets. Asset Management Asset Management Income [Member] Investment Banking, Equities, and Fixed Income Investment Banking, Equities, and Fixed Income [Member] Investment Banking, Equities, and Fixed Income [Member] Goodwill [Line Items] Goodwill [Line Items] Goodwill [Roll Forward] Goodwill [Roll Forward] Goodwill, Beginning Balance Goodwill Translation adjustments Goodwill, Foreign Currency Translation Gain (Loss) Goodwill, Ending Balance Transfers and Servicing [Abstract] Securitization Activities Transfers and Servicing of Financial Assets [Text Block] Statement of Comprehensive Income [Abstract] Changes in instrument specific credit risk, tax expense (benefit) Other Comprehensive Income (Loss), Changes in Instrument Specific Credit Risk, Tax Other Comprehensive Income (Loss), Changes in Instrument Specific Credit Risk, Tax 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] Number of operating segments Number of Operating Segments 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 Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Equity Long/Short Hedge Funds Hedge Funds, Equity Long (Short) [Member] Fixed Income and High Yield Hedge Funds High Yield Hedge Funds [Member] High Yield Hedge Funds. Fund of Funds Fund Of Funds [Member] Fund of Funds. Private equity funds Private Equity Funds [Member] Multi-asset Funds Multi-asset Funds [Member] Multi-asset 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 Investments, Fair Value Disclosure Unfunded Commitments Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments Percentage of investment at fair value in liquidation Percentage of Investment at Fair Value in Liquidation Percentage of Investment at Fair Value in Liquidation Estimated period for the liquidation of the underlying assets, minimum Estimated Period For Liquidation Of Underlying Assets Minimum Estimated period for the liquidation of the underlying assets, Minimum. Estimated period for the liquidation of the underlying assets, maximum Estimated Period For Liquidation Of Underlying Assets Maximum Estimated period for the liquidation of the underlying assets, maximum. Percentage of redeemable investments Redeemable Investments Investments redeemable within 60-90 days Notice period redemption of investment 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. Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] 4.850% Senior Notes Four Point Eight Five Percentage Senior Notes, Due 2027 [Member] Four Point Eight Five Percentage Senior Notes, Due 2027 [Member] 3.875% Convertible Senior Debentures Three Point Eight Seven Five Percentage Convertible Senior Debentures Due Two Thousand Twenty Nine [Member] 3.875% Convertible Senior Debentures, due, 2029. 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 Debt Unsecured Debt [Member] Senior Notes Senior Notes [Member] Class A Notes, Due 2022 Class A Notes, Due 2022 [Member] Class A Notes, Due 2022 [Member] Class B Notes, Due 2022 Class B Notes, Due 2022 [Member] Class B Notes, Due 2022 [Member] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Leucadia Leucadia [Member] Leucadia. Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent event Subsequent Event [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Decrease of long-term debt Increase (Decrease) of Long-term Debt Increase (Decrease) of Long-term Debt Long-term debt at fair value Long-term Debt, Fair Value Long-term debt Long-term Debt Debt instrument interest rate Debt Instrument, Interest Rate, Stated Percentage Debenture principal amount Convertible Debenture Principal Amount Principal amount of each Convertible debenture. Debt instrument convertible conversion ratio Debt Instrument, Convertible, Conversion Ratio Conversion price of common stock (dollars per share) Debt Instrument, Convertible, Conversion Price Debt instrument convertible conversion ratio (greater than) Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger Earliest period of conversion price Debt Instrument, Convertible, Threshold Of Trading Days Debt Instrument, Convertible, Threshold Of Trading Days Latest period of conversion price Debt Instrument, Convertible, Threshold Consecutive Trading Days Less than trading price per debenture related to common stock Percentage Of Debt Instrument Convertible Conversion Ratio Percentage of debt instrument convertible conversion ratio. Consecutive trading days Trading Days Consider For Lower Range Of Stock Price Trading days consider for lower range of stock price. Contingent interest Debt Instrument, Convertible, Contingent Interest Debt Instrument, Convertible, Contingent Interest Threshold trading days Debt Instrument, Convertible, Contingent Interest, Threshold Trading Days Debt Instrument, Convertible, Contingent Interest, Threshold Trading Days Interest period Debt Instrument, Convertible, Interest Period Debt Instrument, Convertible, Interest Period Trading price of contingent interest Threshold Trading Price Of Contingent Interest Trading price before accruing contingent interest. Accounting Policies [Abstract] Summary of Significant Accounting Policies Significant Accounting Policies [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] 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] Total Notional Derivative, Notional Amount Trading Securities [Table] Trading Securities [Table] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] 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] CLOs Collateralized Loan Obligations [Member] Consumer and other loans Other Debt Obligations [Member] Schedule of Trading Securities and Other Trading Assets [Line Items] Schedule of Trading Securities and Other Trading Assets [Line Items] 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 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] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument Not Designated as Hedging Instrument [Member] 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] Adjustments for Change in Accounting Principle [Axis] Adjustments for Change in Accounting Principle [Axis] Adjustments for Change in Accounting Principle [Domain] Adjustments for Change in Accounting Principle [Domain] Rule Change by Chicago Mercantile Exchange Rule Change by Chicago Mercantile Exchange [Member] Rule Change by Chicago Mercantile Exchange [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, Fair Value, Amount Offset Against Collateral Amounts offset in the Consolidated Statements of Financial Condition, Liabilities Derivative Liability, Fair Value, Amount Offset Against Collateral Net amounts per Consolidated Statements of Financial Condition, Assets Financial Instruments, Owned, Derivatives and Other Contractual Agreements, at Fair Value Net amounts per Consolidated Statements of Financial Condition, Liabilities Financial Instruments Sold, Not yet Purchased, Derivatives and Other Contracts Brokers and Dealers [Abstract] Net Capital, Adjusted and Excess Net Capital Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block] Equity Method Investments and Joint Ventures [Abstract] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Jefferies Finance, LLC Jefferies Finance Llc [Member] Jefferies Finance LLC. Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Interest income Investments in and Advances to Affiliates, Dividend or Interest Credited to Income Unfunded commitment fees Line of Credit Facility, Unfunded Commitment Fee Income Line of Credit Facility, Unfunded Commitment Fee Income Our total equity balance Equity Method Investments Net earnings (loss) Equity Method Investment, Summarized Financial Information, Net Income (Loss) Origination and syndication fee revenues Fees Earned To Joint Venture Related To Loan Origination Fees paid to joint venture related to loan origination. Origination fee expenses Fees Paid To Joint Venture Related To Loan Origination Fees paid to joint venture related to loan origination. CLO placement fee revenues Brokerage Commissions Revenue Derivative gains (losses) Derivative, Gain (Loss) on Derivative, Net Service fees Administrative Services Revenue 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 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. 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. 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. Municipal securities Municipal Bonds [Member] Financial Instrument [Axis] Financial Instruments [Domain] Long-term debt Long-term Debt [Member] Level 1 Fair Value, Inputs, Level 1 [Member] Investments at fair value Investments, Net Asset Value, Fair Value Disclosure Investments, Net Asset Value, Fair Value Disclosure Transfers of assets from Level 2 to Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 Transfers of assets from Level 3 to Level 2 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 Transfers of liabilities from Level 3 to Level 2 Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3 Net gains/(losses) on Level 3 assets (realized and unrealized) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Net gains/(losses) on Level 3 liabilities (realized and unrealized) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Aggregate fair value of loans and other receivables on nonaccrual status and/or greater than 90 days past due Fair Value, Option, Loans Held as Assets, Aggregate Amount in Nonaccrual Status Loans and other receivables greater than 90 days past due Fair Value, Option, Loans Held as Assets, 90 Days or More Past Due Other changes in fair value Fair Value, Option, Changes in Fair Value, Gain (Loss) Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations includes U.S. treasury securities Cash and Securities Segregated under Federal and Other Regulations Equity swaps and options Equity Swaps And Options [Member] Equity Swaps And Options [Member] 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 Forward Contracts [Member] Fixed Income Forward Contracts [Member] Interest rate swaps, options and forwards Interest Rate Swaps, Options and Forwards [Member] Interest Rate Swaps, Options and Forwards [Member] 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 Cross-Maturity 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 Cross Maturity 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 Financial instruments sold, not yet purchased Otc Derivative Liabilities Included In Financial Instruments Sold Not Yet Purchased OTC Derivative Liabilities Included In Financial Instruments Sold Not Yet Purchased. Exchange traded derivative assets Exchange Traded Derivative Assets Fair value of exchange traded derivative assets. Cash collateral received Cash Collateral Received Cash collateral received that was netted against OTC derivative assets. Exchange traded derivative liabilities, with fair value Exchange Traded Derivative Liabilities Fair value of exchange traded derivative liabilities. Cash collateral pledged Cash Collateral Pledge Cash collateral pledged that was netted against OTC derivative liabilities. Revenues from External Customers and Long-Lived Assets [Line Items] Revenues from External Customers and Long-Lived Assets [Line Items] Non-interest expenses Noninterest Expense Earnings (loss) before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Segment assets Assets Commissions and other fees Principal transactions Principal Transactions Revenue, Net Investment banking Investment Banking Revenue Asset management fees and investment income from managed funds Asset Management Fees And Investment Income Loss From Managed Funds Revenues earned from management, administrative and performance fees from funds managed by the firm, third-party managed funds, and investment income (loss) from investments in these funds. Interest Interest Income, Operating Other Other Operating Income (Expense), Net Total revenues Revenues Interest expense Interest Expense Net revenues 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 Other Other Expenses Total non-compensation expenses Non Compensation Expenses Non Compensation Expenses Total non-interest expenses Earnings (loss) before income taxes Income tax expense Income Tax Expense (Benefit) Net earnings (loss) Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net earnings (loss) attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Net earnings (loss) attributable to Jefferies Group LLC Net Income (Loss) Attributable to Parent KCG KCG Holdings, Inc [Member] KCG Holdings, Inc [Member] Net gains from our investment in KCG Unrealized Gain on Securities Securities borrowed Securities Borrowed Securities loaned Securities Loaned Hedging relationship effective percentage Derivative, Hedging Relationship Effective Percentage Derivative, Hedging Relationship Effective Percentage JCP Fund V JCP Funds [Member] JCP Funds [Member] Investments in managed funds 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 Ownership percentage Equity Method Investment, Ownership Percentage Net Capital Requirements [Table] Net Capital Requirements [Table] Net Capital Requirements [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Jefferies Jefferies [Member] A registered broker dealer under the Securities and Exchange act of 1934 and a wholly owned subsidiary of the Parent (Jefferies). Jefferies Execution Jefferies Execution [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 Schedule of Guarantor Obligations [Table] Schedule of Guarantor Obligations [Table] 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. Guarantee Obligations [Line Items] Guarantor Obligations [Line Items] 2017 Guarantees Expected To Be Due Current Guarantees with a remaining term that matures during the fiscal year. These may include derivative guarantees, etc. 2018 Guarantees Expected To Be Due In Two Years Guarantees expected to be due within 2 fiscal years. These may include, derivative guarantees, etc. 2019 and 2020 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. 2021 and 2022 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. 2023 and Later Guarantees Expected To Be Due Thereafter Guarantees expected to be due within 7 fiscal years and thereafter. These may include, derivative guarantees, etc Notional/ Maximum Payout Guarantor Obligations, Maximum Exposure, Undiscounted Banking and Thrift [Abstract] 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 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 Schedule of Gain (Loss) on Investments [Table] Schedule of Gain (Loss) on Investments [Table] Securities or Other Assets Sold under Agreements to Repurchase [Axis] Securities or Other Assets Sold under Agreements to Repurchase [Axis] Assets Sold under Agreements to Repurchase, Type [Domain] Assets Sold under Agreements to Repurchase, Type [Domain] Loan commitments Loan Commitments [Member] Loan commitments. Short-term borrowing Short-term Debt [Member] Gain (Loss) on Investments [Line Items] Gain (Loss) on Investments [Line Items] Financial instruments owned: Financial Instruments, Owned, at Fair Value [Abstract] Loans and other receivables Fair Value, Option, Credit Risk, Gains (Losses) on Assets Financial Instruments Sold and Long-term Debt Financial Instruments Sold, Not yet Purchased, at Fair Value [Abstract] Gains (losses) due to changes in instrument specific credit risk Fair Value, Option, Credit Risk, Gains (Losses) on Liabilities 5.125% Senior Notes Five Point One Two Five Percentage Senior Notes Due Two Thousand Eighteen [Member] 5.125% Senior Notes, due 2018. 8.500% Senior Notes Eight Point Five Percentage Senior Notes Due Two Thousand Nineteen [Member] 8.5% Senior Notes, due 2019. 2.375% Euro Medium Term Notes Two Point Three Seven Five Percentage Euro Medium Term Notes Due Two Thousand Twenty [Member] Two Point Three Seven Five Percentage Euro Medium Term Notes Due Two Thousand Twenty [Member] 6.875% Senior Notes Six Point Eight Seven Five Percentage Senior Notes Due Two Thousand Twenty One [Member] 6.875% Senior Note, due 2021. 2.250% Euro Medium Term Notes Two Point Two Five Percentage Euro Medium Term Notes Due Two Thousand Twenty Two [Member] 2.25 % Euro Medium Term Notes due 2022. 5.125% Senior Notes Five Point One Two Five Percentage Senior Notes Due Two Thousand Twenty Three [Member] 5.125 % Senior Notes due 2023. 6.450% Senior Debentures Six Point Four Five Percentage Senior Debentures Due Two Thousand Twenty Seven [Member] 6.45% Senior Debentures due 2027. 6.250% Senior Debentures Six Point Two Five Percentage Senior Debentures Due Two Thousand Thirty Six [Member] 6.25% Senior Debentures, due 2036. 6.500% Senior Notes Six Point Five Zero Percentage Senior Notes Due Two Thousand Forty Three [Member] 6.50% Senior Notes due 2043. Effective Interest Rate Debt Instrument, Interest Rate, Effective Percentage Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Restructuring and Related Activities [Abstract] Restructuring and Related Costs Restructuring and Related Costs [Table Text Block] Restricted stock and RSUs Restricted Stock and Restricted Stock Units [Member] Restricted Stock and Restricted Stock Units [Member] Restricted cash awards Deferred Compensation Arrangement with Individual, Compensation Expense Restricted stock and RSUs Share-based Compensation Profit sharing plan Compensation Cost Related To Profit Sharing Plan Compensation cost related to profit sharing plan. Total compensation cost Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost Collateralized Transactions Repurchase Agreements, Resale Agreements, Securities Borrowed, and Securities Loaned Disclosure [Text Block] Variable Interest Entities Variable Interest Entity Disclosure [Text Block] Fair value of securities received as collateral Fair Value of Securities Received as Collateral that Can be Resold or Repledged Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations Aggregate amortization expense Amortization of Intangible Assets Remainder of fiscal 2017 Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year Year ended November 30, 2018 Finite-Lived Intangible Assets, Amortization Expense, Year Two Year ended November 30, 2019 Finite-Lived Intangible Assets, Amortization Expense, Year Three Year ended November 30, 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Four Year ended November 30, 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Five Carrying value of assets resulting from transfers Carrying Value Of Assets Resulting From Transfers Carrying Value Of Assets Resulting From Transfers Carrying value of liabilities resulting from transfers Carrying Value Of Liabilities Resulting From Transfers Carrying Value Of Liabilities Resulting From Transfers Sovereign obligations Sovereign Debt Securities [Member] Liability Class [Axis] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] 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 Total gains/(losses) (realized and unrealized) 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 Change in unrealized gains/(losses) 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 Total gains/(losses) (realized and unrealized) 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 Change in unrealized gains/ (losses) relating to instruments still held Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss) Fair Value Disclosures Fair Value Disclosures [Text Block] Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Table] [Table] Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Table] [Table] Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Table] [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] 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 And Clearing Organization Membership Interests And Registrations [Member] Exchange and clearing organization membership interests and registrations. Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Table] [Line Items] Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Table] [Line Items] [Line Items] for Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Table] [Table] Gross costs - finite lived intangible assets Finite-Lived Intangible Assets, Gross 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) Impairment losses Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill) Accumulated amortization - finite lived intangible assets Finite-Lived Intangible Assets, Accumulated Amortization Net carrying amount - finite lived intangible assets Finite-Lived Intangible Assets, Net 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) Weighted average remaining lives (years) Finite-Lived Intangible Asset, Useful Life Unrecognized tax benefits Unrecognized Tax Benefits Unrecognized tax benefits that would impact effective tax rate in future Unrecognized Tax Benefits that Would Impact Effective Tax Rate Accrued interest on unrecognized tax benefits Unrecognized Tax Benefits, Interest on Income Taxes Accrued Exit Costs Restructuring and Related Activities Disclosure [Text Block] Schedule of Restructuring and Related Costs [Table] Schedule of Restructuring and Related Costs [Table] Restructuring Type [Axis] Restructuring Type [Axis] Type of Restructuring [Domain] Type of Restructuring [Domain] Severance costs Employee Severance [Member] Accelerated amortization of restricted stock and restricted cash awards Accelerated Amortization of Restricted Stock and Restricted Cash Awards [Member] Accelerated Amortization of Restricted Stock and Restricted Cash Awards [Member] Contract termination costs Contract Termination [Member] Other expenses Other Restructuring [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Compensation and benefits Compensation and Benefits [Member] Compensation and Benefits [Member] Technology and communications Technology and Communications [Member] Technology and Communications [Member] Other expenses Other Expense [Member] Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Restructuring and impairment costs Restructuring and Related Cost, Impairment Costs Restructuring and Related Cost, Impairment Costs Statement of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net earnings (loss) Adjustments to reconcile net earnings (loss) to net cash provided by (used in) operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization (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 Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities Net change in assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations (Decrease) Increase In Cash And Securities Segregated And On Deposit For Regulatory Purposes Or Deposited With Clearing And Depository Organizations The net change during the reporting period of the amount of cash subject to withdrawal restrictions, restricted deposits held as compensating balances and cash and securities segregated in compliance with regulations. Receivables: Increase (Decrease) in Receivables [Abstract] Brokers, dealers and clearing organizations Increase (Decrease) in Receivables from Brokers-Dealers and Clearing Organizations Customers Increase Decrease In Customers Receivable The net change during the reporting period of the amounts due from customers for fees and charges arising from transactions related to the entity's brokerage activities and operations. Fees, interest and other Increase (Decrease) in Other Receivables Securities borrowed Increase (Decrease) in Securities Borrowed Financial instruments owned Increase (Decrease) in Financial Instruments Used in Operating Activities Investments in managed funds Increase Decrease In Investments In Managed Funds The net change during the reporting period of the investments in funds managed by the firm and investments in third-party managed funds in which we are entitled to a portion of the management and/or performance fees. Securities purchased under agreements to resell Increase (Decrease) in Receivables under Repurchase Agreements Other assets Increase (Decrease) in Other Operating Assets Payables: Increase (Decrease) in Operating Liabilities [Abstract] Brokers, dealers and clearing organizations Increase (Decrease) in Payables to Broker-Dealers and Clearing Organizations Customers Increase (Decrease) in Payables to Customers Securities loaned Increase (Decrease) in Securities Loaned Transactions Financial instruments sold, not yet purchased Increase (Decrease) in Financial Instruments Sold, Not yet Purchased Securities sold under agreements to repurchase Increase (Decrease) in Payables under Repurchase Agreements 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] Contributions to loans to and investments in related parties Payments to Fund Long-term Loans to Related Parties Distributions from loans to and investments in related parties Proceeds from Collection of Long-term Loans to Related Parties Net payments on premises and equipment Payments to Acquire Property, Plant, and Equipment Payment on purchase of aircraft Payments to Acquire Other Property, Plant, and Equipment Proceeds from sale of aircraft Proceeds from Sale of Other Property, Plant, and Equipment Deconsolidation of asset management entity Deconsolidation of Asset Management Entity Deconsolidation of Asset Management Entity 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 Net payments on other secured financings Proceeds from (Payments for) Other Financing Activities 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 Net change in bank overdrafts Proceeds from (Repayments of) Bank Overdrafts Net proceeds from noncontrolling interests Proceeds from Noncontrolling Interests Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Effect of exchange rate changes on cash and cash equivalents Effect of Exchange Rate on Cash and Cash Equivalents Net increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of period Supplemental disclosures of cash flow information: Supplemental Cash Flow Information [Abstract] Cash paid (received) during the period for Cash Paid Received During Period [Abstract] Cash paid (received) during the period for: Interest Interest Paid Income taxes, net Income Taxes Paid, Net Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Table] Interest rate swaps Derivative Financial Instruments, Assets [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 Document And Entity Information [Abstract] Document and Entity Information Abstract. Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Related party private equity vehicles Private Equity Vehicles [Member] Private equity vehicles. Other private investment vehicles Other Private Investment Vehicles [Member] Other Private Investment Vehicles [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] JCP Entities JCP Entities [Member] JCP Entities [Member] Jefferies Energy Partners I, LP Jefferies Energy Partners I LP [Member] Jefferies Energy Partners I LP [Member] Agency mortgage-backed securities Mortgage And Asset Backed Securitization Activity Agency [Member] Mortgage and asset backed securitization activity agency. Non agency mortgage-backed securities Mortgage And Asset Backed Securitization Activity Non Agency [Member] Mortgage and asset backed securitization activity non agency. Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Equity investments Equity Commitments Committed equity capitalization. Funded equity commitments Funded Equity Commitments Funded amount of the committed equity capitalization at the balance sheet date. Carrying amount of equity investment Carrying Amount Of Equity Investments Carrying amount of equity investments. Maximum exposure Guarantee Obligations Maximum Exposure Fair Value Guarantee obligations maximum exposure fair value. Carrying amount Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Member's paid-in capital Additional Paid-in Capital [Member] Accumulated other comprehensive income (loss) AOCI Attributable to Parent [Member] Parent Parent [Member] Noncontrolling interests Noncontrolling Interest [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Equity, Beginning Balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Net earnings attributable to Jefferies Group LLC Net Income Attributable To Parent Net Income Loss Available To Common Stockholders Basic Net Income Attributable To Parent Net Income Loss Available To Common Stockholders Basic Tax detriment for issuance of share-based awards Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation Currency adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Changes in instrument specific credit risk, net of tax Other Comprehensive Income Loss Changes in Instrument Specific Credit Risk, Net of Tax Other Comprehensive Income Loss Changes in Instrument Specific Credit Risk, Net of Tax Cash flow hedges Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Pension adjustments, net of tax Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax Net earnings (loss) attributable to noncontrolling interests Contributions Noncontrolling Interest, Increase from Subsidiary Equity Issuance Distributions Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Deconsolidation of asset management company Consolidation Deconsolidation Of Asset Management Entity Consolidation Deconsolidation Of Asset Management Entity Equity, Ending Balance 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. Net Capital Requirements Regulatory Capital Requirements Disclosure [Text Block] Regulatory capital requirements disclosure. Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Securitization Vehicles Securitization Activity [Member] Securitization Activity [Member] Other Other Activity [Member] Other activity. Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Cash Cash [Member] Securities purchased under agreement to resell Securities Purchased Under Agreement [Member] Securities Purchased Under Agreement [Member] Fees, interest and other receivables Fees, Interest and Other Receivables [Member] Fees, Interest and Other Receivables [Member] Other secured financings Other Secured Financings [Member] Other Secured Financings [Member] Other liabilities Other Liabilities [Member] Assets Variable Interest Entity, Consolidated, Carrying Amount, Assets Liabilities Variable Interest Entity, Consolidated, Carrying Amount, Liabilities Secured financing included in inventory and eliminated Vie Secured Financing Eliminated In Consolidation Secured financing held by The Company in Inventory and eliminated in consolidation. Schedule of Collateralized Financing Transactions Schedule of Collateralized Financing Transactions [Table Text Block] Schedule of Collateralized Financing Transactions [Table Text Block] Summary of Repurchase Agreements and Securities Borrowing and Lending Arrangements Offsetting Assets and Liabilities [Table Text Block] Offsetting Assets and Liabilities [Table Text Block] Other Commitments [Table] Other Commitments [Table] Equity commitments Equity Commitments [Member] Equity commitments. Mortgage-related and other purchase commitments Mortgage Related Commitments [Member] Mortgage-related commitments. Underwriting commitments Underwriting Commitments [Member] Underwriting Commitments [Member] Forward starting reverse repos Forward Starting Reverse Repos [Member] Forward Starting Reverse Repos [Member] Forward starting repos Forward Starting Repos [Member] Forward Starting Repos [Member] Other unfunded commitments Other Commitments [Member] Other Commitments [Member] Other Commitments [Line Items] Other Commitments [Line Items] 2017 Contractual Obligation, Future Minimum Payments Due, Remainder of Fiscal Year 2018 Contractual Obligation, Due in Second Year 2019 and 2020 Contractual Obligation, Due in Third and Fourth Year Contractual Obligation, Due in Third and Fourth Year 2021 and 2022 Contractual Obligation, Due in fifth and Sixth Year Contractual Obligation, Due in fifth and Sixth Year 2023 and Later Contractual Obligation, Due After Sixth Year Contractual Obligation, Due After Sixth Year Maximum Payout Contractual Obligation Guarantor obligation settled period (in days) Guarantor Obligation Settled Period Guarantor Obligation Settled Period Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Equity Method Investee Equity Method Investee [Member] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Equity Investments in Jefferies Capital Partners Related Funds Equity Investments in Jefferies Capital Partners Related Funds [Member] Equity Investments in Jefferies Capital Partners Related Funds [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Other revenues and investment income (loss) Other Revenues And Investment Income Loss On Private Equity Related Investments Other Revenues And Investment Income Loss On Private Equity Related Investments Service charges Related Party Transaction, Other Revenues from Transactions with Related Party Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Level 2 Fair Value, Inputs, Level 2 [Member] Financial Instruments Owned and Pledged as Collateral by Type [Axis] Financial Instruments Owned and Pledged as Collateral by Type [Axis] Financial Instruments Owned and Pledged as Collateral, Type [Domain] Financial Instruments Owned and Pledged as Collateral, Type [Domain] Residential mortgage-backed securities Commercial mortgage-backed securities Other asset-backed securities 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] Assets: Fair Value Assets Measured On Recurring Basis [Abstract] Fair value assets measured on recurring basis. Corporate equity securities Financial Instruments, Owned, Corporate Equities, at Fair Value Corporate debt securities Financial Instruments, Owned, Corporate Debt, at Fair Value Collateralized debt obligations and collateralized loan obligations Financial Instruments Owned Collateralized Debt Obligations At Fair Value The fair value as of the balance sheet date of firm holdings in structured asset - backed securities whose value and payments are derived from portfolio of fixed income underlying assets. U.S. government and federal agency securities Financial Instruments, Owned, US Government and Agency Obligations, at Fair Value Municipal securities Financial Instruments, Owned, State and Municipal Government Obligations, at Fair Value Sovereign obligations Financial Instruments, Owned, Other Sovereign Government Obligations, at Fair Value Mortgage- and asset-backed securities, assets Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value Loans and other receivables Financial Instruments Owned Loans And Other Receivables The fair value as of the balance sheet date of firm holdings in corporate loans, participation certificates in GNMA project and construction loans, and escrow and trade claim receivables. Derivatives Investments at fair value Financial Instruments, Owned, Principal Investments, at Fair Value Total financial instruments owned, excluding Investments at fair value based on NAV Financial Instruments, Owned, at Fair Value Excluding Investments at Net Asset Value Financial Instruments, Owned, at Fair Value Excluding Investments at Net Asset Value Counterparty and Cash Collateral Netting Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset Liabilities: Fair Value Liabilities Measured On Recurring Basis [Abstract] Fair value liabilities measured on recurring basis. Financial instruments sold, not yet purchased: Corporate equity securities Financial Instruments Sold, Not yet Purchased, Corporate Equities Corporate debt securities Financial Instruments Sold, Not yet Purchased, Corporate Debt U.S. government and federal agency securities Financial Instruments Sold, Not yet Purchased, US Government and Agency Obligations Municipal securities Financial Instruments Sold, Not yet Purchased, State and Municipal Government Obligations Sovereign obligations Financial Instruments Sold, Not yet Purchased, Other Sovereign Government Debt Commercial mortgage-backed securities Financial Instruments Sold, Not yet Purchased, Mortgages, Mortgage-backed and Asset-backed Securities Loans Fair Value Of Loan Obligations Fair value of loan obligations. Derivatives Total financial instruments sold, not yet purchased Financial Instruments Sold, Not yet Purchased, at Fair Value Counterparty and Cash Collateral Netting Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset Other secured financings Secured Debt, Other Short-term borrowings Short-term Debt, Fair Value Long-term debt Schedule of Short-term Borrowings Schedule of Short-term Debt [Table Text Block] 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 Additional Amounts Available for Setoff Securities Borrowed, Not Offset, Policy Election Deduction Available Collateral Securities Borrowed, Fair Value of Collateral Net Amount Securities Borrowed, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election 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 Additional Amounts Available for Setoff Securities Loaned, Not Offset, Policy Election Deduction Available Collateral Securities Loaned, Fair Value of Collateral Net Amount Securities Loaned, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election 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 Long-Term Debt Long-term Debt [Text Block] Cost of acquired entity cash paid per share (in USD per share) Business Acquisition Cost Of Acquired Entity Cash Paid Per Share Business Acquisition Cost Of Acquired Entity Cash Paid Per Share Short-Term Borrowings Short-term Debt [Text Block] Nonconsolidated VIEs Variable Interest Entity, Not Primary Beneficiary [Member] Consumer loan vehicles Consumer Loan Financing Vehicles [Member] Consumer Loan Financing Vehicles [Member] Carrying Amount, Assets Carrying Amount, Liabilities 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 Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Cash and cash equivalents ($6,242 and $16,805 at August 31, 2017 and November 30, 2016, respectively, related to consolidated VIEs) Cash and Cash Equivalents, Fair Value Disclosure Financial instruments owned, at fair value, (including securities pledged of $10,257,188 and $9,706,881 at August 31, 2017 and November 30, 2016, respectively; and $44,862 and $87,153 at August 31, 2017 and November 30, 2016, respectively, related to consolidated VIEs) Financial Instruments, Owned, at Fair Value Investments in managed funds Investments In Managed Funds The fair value as of the balance sheet date of the firm's investments in funds managed by us and investments in third-party managed funds in which we are entitled to a portion of the management and/or performance fees. Loans to and investments in related parties Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Securities borrowed Securities purchased under agreements to resell Receivables: Receivables [Abstract] Brokers, dealers and clearing organizations Receivables from Brokers-Dealers and Clearing Organizations Customers Receivables from Customers Fees, interest and other ($245 and $1,547 at August 31, 2017 and November 30, 2016, respectively, related to consolidated VIEs) Fees Interest And Other Represents accounts receivable from clients, counterparties and others, interest income receivable, dividend income receivable, fees receivable, and other receivables from suppliers, insurance companies and amounts due from third parties. Premises and equipment Property, Plant and Equipment, Net Goodwill Other assets ($3 and $0 at August 31, 2017 and November 30, 2016, respectively, related to consolidated VIEs) Other Assets Total assets LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Financial instruments sold, not yet purchased, at fair value Collateralized financings: Collateralized Financings [Abstract] Securities loaned Securities sold under agreements to repurchase Other secured financings (includes $0 and $41,768 at fair value at August 31, 2017 and November 30, 2016, respectively; and $541,500 and $755,544 at August 31, 2017 and November 30, 2016, respectively, related to consolidated VIEs) Other Secured Financings Payables: Payables [Abstract] Payables. Brokers, dealers and clearing organizations Payables to Broker-Dealers and Clearing Organizations Customers Payables to Customers Accrued expenses and other liabilities ($800 and $735 at August 31, 2017 and November 30, 2016, respectively, related to consolidated VIEs) Accounts Payable and Accrued Liabilities Long-term debt (includes $553,870 and $248,856 at fair value at August 31, 2017 and November 30, 2016, respectively) Total liabilities Liabilities EQUITY Equity [Abstract] Member’s paid-in capital Additional Paid in Capital, Common Stock Accumulated other comprehensive 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), Pension and Other Postretirement Benefit Plans, Net of 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 Noncontrolling interests Stockholders' Equity Attributable to Noncontrolling Interest Total equity Equity And Members Equity Stockholders Equity Including Portion Attributable To Noncontrolling Interest Equity And Members Equity Stockholders Equity Including Portion Attributable To Noncontrolling Interest Total liabilities and equity Liabilities Equity And Members Equity Stockholders Equity Liabilities Equity And Members Equity Stockholders Equity Schedule of Goodwill Schedule of Goodwill [Table Text Block] Summary of Intangible Assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Future Amortization Expense Related to Intangible Assets Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Title of Individual [Axis] Title of Individual [Axis] Relationship to Entity [Domain] Relationship to Entity [Domain] Director Director [Member] Counterparty Name [Axis] Counterparty Name [Axis]