Goodwill and Intangible Assets Disclosure [Abstract] Intangible Assets, Net and Goodwill Goodwill and Intangible Assets Disclosure [Text Block] Selected Quarterly Financial Information [Abstract] Net revenues Revenues, Net of Interest Expense Income from continuing operations Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Income from discontinued operations, net of taxes Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax Gain on disposal of discontinued operations, net of taxes Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax Net (income) loss attributable to the noncontrolling interest Net Income (Loss) Attributable to Noncontrolling Interest Net (income) loss attributable to the redeemable noncontrolling interests Net Income (Loss) Attributable to Redeemable Noncontrolling Interest Preferred stock dividends Preferred Stock Dividends, Income Statement Impact Net income attributable to Jefferies Financial Group Inc. common shareholders Net Income (Loss) Attributable to Parent Basic earnings (loss) per common share attributable to Jefferies Financial Group Inc. common shareholders: Earnings Per Share, Basic [Abstract] Income (loss) from continuing operations (USD per share) Income (Loss) from Continuing Operations, Per Basic Share Income from discontinued operations (USD per share) Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share Gain on disposal of discontinued operations (USD per share) Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax, Per Basic Share Net income (USD per share) Earnings Per Share, Basic Number of shares used in calculation - basic (shares) Weighted Average Number of Shares Outstanding, Basic Diluted earnings (loss) per common share attributable to Jefferies Financial Group Inc. common shareholders: Earnings Per Share, Diluted [Abstract] Income (loss) from continuing operations (USD per share) Income (Loss) from Continuing Operations, Per Diluted Share Income from discontinued operations (USD per share) Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share Gain on disposal of discontinued operations - diluted (USD per share) Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax, Per Diluted Share Net income (USD per share) Earnings Per Share, Diluted Number of shares used in calculation - diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] HomeFed HomeFed LLC [Member] HomeFed LLC - Member Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Discontinued operations, disposed of by sale Discontinued Operations, Disposed of by Sale [Member] Disposal group, disposed of by sale, not discontinued operations Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Spectrum Brands Spectrum Brands Holdings, Inc. [Member] Spectrum Brands Holdings, Inc. [Member] HRG Hrg Group [Member] HRG Group [Member] The We Company The We Company [Member] The We Company [Member] Investment in FXCM Investment in FXCM [Member] Investment in FXCM [Member] National Beef National Beef [Member] National Beef [Member] Investment In Golden Queen Investment In Golden Queen [Member] Investment In Golden Queen [Member] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] Garcadia Garcadia [Member] Garcadia Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income (loss) related to associated companies Income (Loss) from Equity Method Investments Increase (decrease) in fair value of investments Changes in Fair Value of Investments Changes in Fair Value of Investments Pre-tax gain recognized on acquisition Business Combination, Pre-Tax Gain (Loss) Business Combination, Pre-Tax Gain (Loss) Gain on sale of associated companies Equity Method Investment, Realized Gain (Loss) on Disposal Recognition of accumulated other comprehensive income lodged taxes Recognition Of Accumulated Other Comprehensive Income Lodged Taxes Recognition Of Accumulated Other Comprehensive Income Lodged Taxes Pre-tax gain on sale of equity interests and associated real estate Gain (Loss) On Sale Of Equity Method Investments And Associated Real Estate Subsidiaries Gain (Loss) On Sale Of Equity Method Investments And Associated Real Estate Subsidiaries Equity method investment impairment Equity Method Investment, Other than Temporary Impairment Percentage of equity interest sold Equity Method Investment, Percentage Of Interest Sold Equity Method Investment, Percentage Of Interest Sold Accounting Policies [Abstract] Cash paid during the year for: Supplemental Cash Flow Information [Abstract] Interest, net of amounts capitalized Interest Paid, Excluding Capitalized Interest, Operating Activities Income tax payments (refunds), net Income Taxes Paid, Net Brokers and Dealers [Abstract] 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 LLC [Member] Jefferies LLC [Member] Net Capital Requirements [Line Items] Net Capital Requirements [Line Items] Net Capital Requirements [Line Items] Net Capital Net Capital Excess Net Capital Alternative Excess Net Capital Consolidation Consolidation, Policy [Policy Text Block] Revenue Recognition Policies Revenue from Contract with Customer [Policy Text Block] Hedge Accounting Derivatives, Methods of Accounting, Hedging Derivatives [Policy Text Block] Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Cash and Securities Segregated and on Deposit for Regulatory Purposes or Deposited With Clearing and Depository Organizations Cash And Securities Segregated And On Deposit For Regulatory Purposes Or Deposited With Clearing And Depository Organizations Policy [Text Block] Cash and Securities Segregated and on Deposit for Regulatory Purposes or Deposited With Clearing and Depository Organizations. Financial Instruments and Fair Value Fair Value of Financial Instruments, Policy [Policy Text Block] Fair Value Hierarchy Fair Value Measurement, Policy [Policy Text Block] Loans to and Investments in Associated Companies Loans to and Investments in Associated Companies [Policy Text Block] Loans to and Investments in Associated Companies [Policy Text Block] Receivables Receivables and Provision for Doubtful Accounts [Policy Text Block] Receivables and Provision for Doubtful Accounts [Policy Text Block] Securities Borrowed And Securities Loaned Securities Borrowed and Loaned Policy [Policy Text Block] Securities Purchased Under Agreements to Resell and Securities Sold Under Agreements to Repurchase Repurchase and Resale Agreements Policy [Policy Text Block] Offsetting of Derivative Financial Instruments and Securities Financing Agreements Derivatives, Offsetting Fair Value Amounts, Policy [Policy Text Block] Property, Equipment and Leasehold Improvements Property, Plant and Equipment, Policy [Policy Text Block] Impairment of Long-Lived Assets Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Intangible Assets, Net and Goodwill Goodwill and Intangible Assets, Policy [Policy Text Block] Inventories and Cost of Sales Inventory, Policy [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Share-based Compensation Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Foreign Currency Translation Foreign Currency Transactions and Translations Policy [Policy Text Block] Earnings per Common Share Earnings Per Share, Policy [Policy Text Block] Securitization Activities Transfers and Servicing of Financial Assets, Policy [Policy Text Block] Contingencies Commitments and Contingencies, Policy [Policy Text Block] Fiscal year Fiscal Period, Policy [Policy Text Block] Accounting Developments New Accounting Pronouncements, Policy [Policy 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] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Investment Banking, Capital Markets and Asset Management Investment Banking, Capital Markets And Asset Management Segment [Member] Investment Banking, Capital Markets And Asset Management Segment [Member] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Americas Americas [Member] Europe Europe [Member] Asia Asia [Member] Revenues from External Customers and Long-Lived Assets [Line Items] Revenues from External Customers and Long-Lived Assets [Line Items] Variable Interest Entity, Measure of Activity [Abstract] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] CLOs Collateralized Loan Obligations [Member] Consumer loan and other asset-backed vehicles Consumer Loan [Member] Related party private equity vehicles Related Party Private Equity Vehicles [Member] Related Party Private Equity Vehicles [Member] 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, Assets of Non Consolidated Vie Variable Interest Entity, Assets of Non Consolidated Vie Statement of Comprehensive Income [Abstract] Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Net unrealized holding gains (losses) on investments arising during the period, net of income tax provision (benefit) of $165, $(551) and $3,450 Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax Less: reclassification adjustment for net (gains) losses included in net income, net of income tax provision (benefit) of $(545,054), $37 and $124 Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Net change in unrealized holding gains (losses) on investments, net of income tax provision (benefit) of $545,219, $(588) and $3,326 Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax Net unrealized foreign exchange gains (losses) arising during the period, net of income tax provision (benefit) of $1,146, $(11,089) and $14,616 Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Less: reclassification adjustment for foreign exchange (gains) losses included in net income, net of income tax provision (benefit) of $(52), $(16) and $1,086 Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax Net change in unrealized foreign exchange gains (losses), net of income tax provision (benefit) of $1,198, $(11,073) and $13,530 Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Net unrealized gains (losses) on instrument specific credit risk arising during the period, net of income tax provision (benefit) of $(4,653), $9,289 and $(13,215) Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Unrealized Gain (Loss) Arising During Period, after Tax Less: reclassification adjustment for instrument specific credit risk (gains) losses included in net income, net of income tax provision (benefit) of $(144), $311 and $0 Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Reclassification Adjustment from AOCI for Derecognition, after Tax Net change in unrealized instrument specific credit risk gains (losses), net of income tax provision (benefit) of $(4,509), $8,978 and $(13,215) Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, after Tax and Reclassification Adjustment Net unrealized gains (losses) on cash flow hedges arising during the period, net of income tax provision (benefit) of $0, $552 and $(593) Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Less: reclassification adjustment for cash flow hedges (gains) losses included in net income, net of income tax provision (benefit) of $161, $0 and $0 Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Net change in unrealized cash flow hedges gains (losses), net of income tax provision (benefit) of $(161), $552 and $(593) Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Net pension gains (losses) arising during the period, net of income tax provision (benefit) of $(2,473), $(297) and $2,018 Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax Less: reclassification adjustment for pension (gains) losses included in net income, net of income tax provision (benefit) of $(490), $(697) and $(2,042) Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax Net change in pension liability benefits, net of income tax provision (benefit) of $(1,983), $400 and $4,060 Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Other comprehensive income (loss), net of income taxes Other Comprehensive Income (Loss), Net of Tax Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive loss attributable to the noncontrolling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Comprehensive (income) loss attributable to the redeemable noncontrolling interests Comprehensive Income (Loss) Net Of Tax Attributable To Redeemable Noncontrolling Interests Comprehensive income or loss net of tax attributable to redeemable noncontrolling interests. Comprehensive income attributable to Jefferies Financial Group Inc. common shareholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Share-based Compensation [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] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Other Stock-Based Plans Other Stock-Based Plans [Member] Other Stock-Based Plans [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Stock available for grant (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Options issued to purchased number of shares (in shares) Options Issued To Purchased Number Of Shares Options Issued To Purchased Number Of Shares Shares reserved for stock options and warrants (in shares) Common Stock, Capital Shares Reserved for Future Issuance Restricted cash awards, cost expected to be recognized Restricted Cash Awards, Compensation Cost Not Yet Recognized Restricted Cash Awards, Compensation Cost Not Yet Recognized Restricted cash awards, cost expected to be recognized, period Restricted Cash Awards, Compensation Cost Not Yet Recognized, Period For Recognition Restricted Cash Awards, Compensation Cost Not Yet Recognized, Period For Recognition Fair Value Disclosures [Abstract] Fair Value Option, Disclosures [Table] Fair Value Option, Disclosures [Table] Long-term debt Long-term Debt [Member] Short-term borrowings Short-term Debt [Member] 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] Financial instruments sold Financial Instruments Sold [Member] Financial Instruments Sold [Member] Fair Value, Option, Quantitative Disclosures [Line Items] Fair Value, Option, Quantitative Disclosures [Line Items] Trading Assets: Fair Value, Option, Credit Risk, Gains (Losses) on Assets Loans Fair Value, Option, Credit Risk, Gains (Losses) on Loans Fair Value, Option, Credit Risk, Gains (Losses) on Loans Loan commitments Fair Value, Option, Credit Risk, Gains (Losses) on Loan Commitments Fair Value, Option, Credit Risk, Gains (Losses) on Loan Commitments Changes in instrument specific credit risk Other changes in fair value Fair Value, Option, Changes in Fair Value, Gain (Loss) Equity Method Investments and Joint Ventures [Abstract] Investment [Table] Investment [Table] Garcadia Companies Investment [Line Items] Investment [Line Items] Proceeds from sale of equity interests and associated real estate Proceeds From Sale Of Equity Method Investments And Associated Real Estate Proceeds From Sale Of Equity Method Investments And Associated Real Estate Pre-tax gain on sale of equity interests and associated real estate Schedule Of Selected Quarterly Financial Data Quarterly Financial Information [Table Text Block] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Restricted Stock Restricted Stock [Member] Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Nonvested balance, beginning of period (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Grants (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Forfeited (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Fulfillment of vesting requirement (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Nonvested balance, end of period (shares) Weighted- Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Nonvested balance, beginning of period (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Grants (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Forfeited (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Fulfillment of vesting requirement (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Nonvested balance, end of period (USD per share) Organization, Consolidation and Presentation of Financial Statements [Abstract] Total expenses Costs and Expenses Income from continuing operations before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax provision (benefit) Income Tax Expense (Benefit) Income from discontinued operations, including gain on disposal, net of taxes Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Net (income) loss attributable to the redeemable noncontrolling interests Net income attributable to Jefferies Financial Group Inc. common shareholders Income from continuing operations (USD per share) Income from discontinued operations, including gain on disposal (USD per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share Income from continuing operations (USD per share) Income from discontinued operations, including gain on disposal (USD per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share 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] Commissions and other fees Commission And Other Fees [Member] Commission And Other Fees [Member] Investment banking Investment Banking [Member] Investment Banking [Member] Manufacturing revenues Manufacturing Revenues [Member] Manufacturing Revenues [Member] Other Revenue From Contract With Customer, Other [Member] Revenue From Contract With Customer, Other [Member] Principal transactions Principal Transactions Revenue [Member] Principal Transactions Revenue [Member] Interest income Interest Revenue [Member] Interest Revenue [Member] Other Other Sources Of Revenue, Miscellaneous [Member] Other Sources Of Revenue, Miscellaneous [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenue from contracts with customers Revenue from Contract with Customer, Excluding Assessed Tax Revenue from other sources Revenue, Other Sources Revenue, Other Sources Total revenues Revenues Nonoperating Income (Expense) [Abstract] Other Results of Operations Information Other Results Of Operations Information Text Block Other Results of Operations Information. Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations Cash and Securities Segregated under Federal and Other Regulations Financial instruments owned, at fair value (includes securities pledged of $12,058,522 and $13,059,802): Financial Instruments, Owned, at Fair Value, by Type, Alternative [Abstract] Trading assets Financial instruments owned trading assets, at fair value Financial Instruments, Owned, Trading Assets, at Fair Value Available for sale securities Debt Securities, Available-for-sale Total financial instruments owned Financial Instruments, Owned, at Fair Value Loans to and investments in associated companies Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Securities borrowed Securities Borrowed Securities purchased under agreements to resell Securities Purchased under Agreements to Resell Securities received as collateral Securities Received as Collateral Receivables Receivables Receivables Intangible assets, net and goodwill Intangible Assets, Net (Including Goodwill) Deferred tax asset, net Deferred Income Tax Assets, Net Other assets Other Assets Total assets Assets LIABILITIES Liabilities [Abstract] Short-term borrowings Short-term Debt Trading liabilities, at fair value Trading Liabilities, Fair Value Disclosure Securities loaned Securities Loaned Securities sold under agreements to repurchase Securities Sold under Agreements to Repurchase Other secured financings Other Secured Financings Obligation to return securities received as collateral Obligation to Return Securities Received as Collateral Payables, expense accruals and other liabilities Payables, expense accruals and other liabilities Payables, expense accruals and other liabilities Long-term debt Long-term Debt Total liabilities Liabilities Commitments and contingencies Commitments and Contingencies MEZZANINE EQUITY Temporary Equity [Abstract] Redeemable noncontrolling interests Redeemable Noncontrolling Interest, Equity, Carrying Amount Mandatorily redeemable convertible preferred shares Mandatorily redeemable convertible preferred shares Mandatorily Redeemable Convertible Preferred Shares EQUITY Stockholders' Equity Attributable to Parent [Abstract] Common shares, par value $1 per share, authorized 600,000,000 shares; 291,644,153 and 307,515,472 shares issued and outstanding, after deducting 24,818,459 and 109,460,774 shares held in treasury Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Retained earnings Retained Earnings (Accumulated Deficit) Total Jefferies Financial Group Inc. shareholders' equity Stockholders' Equity Attributable to Parent Noncontrolling interests Stockholders' Equity Attributable to Noncontrolling Interest Total equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total Liabilities and Equity Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative [Table] Derivative [Table] External Credit Rating by Grouping [Axis] External Credit Rating by Grouping [Axis] External Credit Rating by Grouping [Domain] External Credit Rating by Grouping [Domain] Investment Grade External Credit Rating, Investment Grade [Member] Non-investment Grade External Credit Rating, Non Investment Grade [Member] Unrated Unrated [Member] Unrated [Member] Credit Derivatives Contract Type [Axis] Credit Derivatives Contract Type [Axis] Credit Derivatives Contract Type [Domain] Credit Derivatives Contract Type [Domain] Index credit default swaps Credit Index Product [Member] Single name credit default swaps Credit Default Swap [Member] Derivative [Line Items] Derivative [Line Items] Derivative notional amount Derivative, Notional Amount Revenues from Contracts with Customers Revenue from Contract with Customer [Text Block] Condensed Income Statement Condensed Income Statement [Table Text Block] Assets Equity Method Investment, Summarized Financial Information, Assets Liabilities Equity Method Investment, Summarized Financial Information, Liabilities Noncontrolling interest Equity Method Investment, Summarized Financial Information, Noncontrolling Interest Revenues Equity Method Investment, Summarized Financial Information, Revenue Income from continuing operations before extraordinary items Equity Method Investment, Summarized Financial Information, Income (Loss) from Continuing Operations Net income Equity Method Investment, Summarized Financial Information, Net Income (Loss) The Company's income related to associated companies Income (Losses) Related To Associated Companies, Including Investments Accounted For Under Fair Value Option Income (Losses) Related To Associated Companies, Including Investments Accounted For Under Fair Value Option Undistributed earnings of equity method investments Retained Earnings, Undistributed Earnings from Equity Method Investees Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Loans and other receivables Loans and Finance Receivables [Member] Other asset-backed securities Other Asset Backed Securities [Member] Other asset-backed securities. Corporate debt securities Corporate Debt Securities [Member] Commercial mortgage-backed securities Commercial Mortgage Backed Securities [Member] CDOs and CLOs Collateralized Debt Obligations and Collateralized Loan Obligations [Member] Collateralized Debt Obligations and Collateralized Loan Obligations [Member] Corporate equity securities Equity Securities [Member] Derivatives Derivative [Member] Residential mortgage-backed securities Residential Mortgage Backed Securities [Member] Investments at fair value Investments at Fair Value [Member] Investments at Fair Value [Member] Municipal securities Municipal Bonds [Member] Loans Loans [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] 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 2 to Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3 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 Excluded assets from unobservable quantitative information Excluded Securities from Unobservable Quantitative Information, Assets Excluded Securities from Unobservable Quantitative Information, Assets Excluded liabilities from unobservable quantitative information Excluded Securities from Unobservable Quantitative Information, Liabilities Excluded Securities from Unobservable Quantitative Information, Liabilities Temporary Equity Disclosure [Abstract] Mezzanine Equity Mezzanine Equity Disclosure [Text Block] Mezzanine Equity Disclosure [Text Block] Collateralized debt obligations and collateralized loan obligations U.S. government and federal agency securities US Treasury and Government [Member] Sovereign obligations Sovereign Debt Securities [Member] Loans and other receivables FXCM term loan FXCM Term Loan [Member] FXCM Term Loan [Member] U.S. government securities US Treasury Securities [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Fair Value Measured at NAV Fair Value Measured at Net Asset Value Per Share [Member] Alternative investments Alternative Investment Assets: Financial Instruments, Owned, at Fair Value [Abstract] Trading assets, at fair value Financial Instruments Owned Trading Assets, at Fair Value, Excluding Investments Based on Net Asset Value Financial Instruments Owned Trading Assets, at Fair Value, Excluding Investments Based on Net Asset Value Derivative assets Derivative Asset Counterparty and Cash Collateral Netting, assets Derivative Asset, Fair Value, Gross Liability Securities purchased under agreements to resell Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure Liabilities: Financial Instruments Sold, Not yet Purchased, at Fair Value [Abstract] Derivative liability Derivative Liability Counterparty and Cash Collateral Netting, liabilities Derivative Liability, Fair Value, Gross Asset Short-term borrowings Short-term Debt, Fair Value Long-term debt Long-term Debt, Fair Value Obligation to Return Securities Received as Collateral Transfers and Servicing [Abstract] Schedule of Securitization or Asset-backed Financing Arrangements, Financial Asset for which Transfer is Accounted as Sale [Table] Schedule of Securitization or Asset-backed Financing Arrangements, Financial Asset for which Transfer is Accounted as Sale [Table] Consumer and other loans Consumer and Other Loans [Member] Consumer and Other Loans [Member] Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items] Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items] U.S. government agency residential mortgage-backed securities Rmbs Securitization Assets Represents unpaid principal amount of assets in residential mortgage backed securitization vehicles at the balance sheet date. U.S. government agency commercial mortgage-backed securities Cmbs Securitization Assets Represents unpaid principal amount of assets in commercial mortgage backed securitization vehicles at the balance sheet date. CLOs Collateralized Loan Obligations Securitization Assets Collateralized Loan Obligations Securitization Assets Consumer and other loans Consumer and Other Loans Securitization Assets Consumer and Other Loans Securitization Assets Retained Interests Retained Interest, Fair Value Disclosure Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Derivative, by Nature [Axis] Derivative Instrument [Axis] Derivative, Name [Domain] Derivative Contract [Domain] Commodity swaps, options and forwards Commodity Swaps Options And Forwards [Member] Commodity swaps options and forwards. Equity forwards, swaps and options Equity Forwards Swaps And Options [Member] Equity Forwards Swaps And Options [Member] Credit default swaps Total return swaps Total Return Swap [Member] Foreign currency forwards, swaps and options Foreign Currency Forwards Swaps And Options [Member] Foreign currency forwards swaps and options. Fixed income forwards Fixed Income Forwards [Member] Fixed income forwards. Interest rate swaps, options and forwards Interest Rate Swaps, Options And Forwards [Member] Interest Rate Swaps, Options And Forwards [Member] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] OTC Derivative Assets Otc Derivative Assets [Abstract] Otc Derivative Assets [Abstract] 0-12 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. 1-5 Years Otc Derivative Assets Having Maturity Period Of One To Five Years OTC derivative assets having maturity period of 1 to5 years. 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. Cross- Maturity Netting Otc Derivative Assets Cross Maturity Netting OTC derivative assets cross maturity netting. Total Consolidated Otc Derivative Assets Net Of Crossmaturity Netting Total OTC derivative assets, net of cross-maturity netting. Cross product counterparty netting Derivative Assets Cross Product Counterparty Netting Derivative Assets Cross Product Counterparty Netting. Total OTC derivative assets included in Trading assets Otc Derivative Assets Included In Financial Instruments Owned OTC Derivative Assets Included In Financial Instruments Owned. OTC Derivative Liabilities OTC Derivative Liabilities [Abstract] OTC Derivative Liabilities [Abstract] 0-12 Months Otc Derivative Liabilities Having Maturity Period Of Zero To Twelve Months OTC derivative liabilities having maturity period of zero to twelve months. 1-5 Years Otc Derivative Liabilities Having Maturity Period Of One To Five Years OTC derivative liabilities having maturity period of 1 to 5 years. 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. Cross-Maturity Netting Otc Derivative Liabilities Cross Maturity Netting OTC derivative liabilities cross maturity netting. Total Consolidated Otc Derivative Liabilities Net Of Crossmaturity Netting Total OTC derivative liabilities, net of cross-maturity netting. Cross product counterparty netting Derivative Liabilities Cross Product Counterparty Netting Derivative Liabilities Cross Product Counterparty Netting. Total OTC derivative liabilities included in Trading liabilities OTC Derivative Liabilities Included In Trading Liabilities OTC Derivative Liabilities Included In Trading Liabilities Exchange traded derivative assets and other credit agreements Exchange traded derivative assets and other credit agreements Exchange traded derivative assets and other credit agreements Cash collateral received Cash Collateral Received Cash collateral received that was netted against OTC derivative assets. Exchange traded derivative liabilities and other credit agreements Exchange traded derivative liabilities and other credit agreements Exchange traded derivative liabilities and other credit agreements Cash collateral pledged Cash collateral pledged Cash collateral pledged that was netted against OTC derivative liabilities. Redeemable Noncontrolling Interests in Subsidiary [Table] Redeemable Noncontrolling Interests in Subsidiary [Table] Redeemable Noncontrolling Interests in Subsidiary [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Jefferies Group Jefferies Group LLC [Member] Jefferies Group LLC Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Cumulative Convertible Preferred Shares Redeemable Convertible Preferred Stock [Member] Purchase Requirement [Line Items] Purchase Requirement [Line Items] Purchase Requirement [Line Items] Ownership percentage Ownership Percentage Ownership Percentage Reversal of cumulative National Beef redeemable noncontrolling interests fair value adjustments prior to deconsolidation Reversal Of Cumulative Redeemable Noncontrolling Interests Fair Value Adjustments Prior To Deconsolidation Reversal Of Cumulative Redeemable Noncontrolling Interests Fair Value Adjustments Prior To Deconsolidation Redeemable noncontrolling interests Redeemable Noncontrolling Interest, Equity, Other, Carrying Amount Dividend rate on preferred stock Preferred Stock, Dividend Rate, Percentage Mandatorily redeemable convertible preferred shares redemption value Mandatoriy redeemable preferred stock, number of shares in conversion (in shares) Mandatory Redeemable Preferred Stock, Number of Shares in Conversion Mandatory Redeemable Preferred Stock, Number of Shares in Conversion Mandatorily redeemable preferred stock, effective conversion price per share (USD per share) Mandatory Redeemable Preferred Stock, Effective Conversion Price per Share Mandatory Redeemable Preferred Stock, Effective Conversion Price per Share Minimum common dividend considered for additional quarterly payments Preferred Stock, Minimum Common Dividend Considered For Additional Quarterly Payments Preferred Stock, Minimum Common Dividend Considered For Additional Quarterly Payments Dividends per common share (USD per share) Common Stock, Dividends, Per Share, Declared Preferred stock dividends Dividends per common share, percentage of increase Common Stock, Dividends, Per Share, Increase (Decrease) Percentage Common Stock, Dividends, Per Share, Increase (Decrease) Percentage Preferred stock, effective dividend rate, percentage Preferred Stock, Effective Dividend Rate, Percentage Preferred Stock, Effective Dividend Rate, Percentage Mandatorily redeemable preferred shares callable price per share (USD per share) Mandatorily redeemable preferred shares callable price per share Mandatorily redeemable preferred shares callable price per share 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] U.S. UNITED STATES Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Change in Benefit Obligation [Roll Forward] Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Projected benefit obligation, beginning of year Defined Benefit Plan, Benefit Obligation Interest cost Defined Benefit Plan, Interest Cost Actuarial (gains) losses Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) Settlement payments Defined Benefit Plan, Benefit Obligation, Payment for Settlement Benefits paid Defined Benefit Plan, Benefit Obligation, Benefits Paid Projected benefit obligation, end of year Change in Fair Value of Plan Assets [Roll Forward] Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Fair value of plan assets, beginning of year Defined Benefit Plan, Plan Assets, Amount Actual return on plan assets Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) Employer contributions Defined Benefit Plan, Plan Assets, Contributions by Employer Benefits paid Defined Benefit Plan, Plan Assets, Benefits Paid Settlement payments Defined Benefit Plan, Plan Assets, Payment for Settlement Administrative expenses Defined Benefit Plan, Plan Assets, Administration Expense Fair value of plan assets, end of year Funded status at end of year Defined Benefit Plan, Funded (Unfunded) Status of Plan Investment Type [Axis] Investment Type [Axis] Investment [Domain] Investments [Domain] Cleared OTC Cleared OTC [Member] Cleared OTC [Member] Exchange-traded Exchange Traded Options [Member] Bilateral OTC Bilateral OTC [Member] Bilateral OTC [Member] Derivative Instrument [Axis] 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] Commodity contracts: Credit Contracts [Member] Credit Contracts [Member] 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] 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 Consolidated Statement of Financial Condition, Assets Derivative Asset, Collateral, Obligation to Return Cash, Offset Amounts offset in Consolidated Statement of Financial Condition, Liabilities Derivative Liability, Collateral, Right to Reclaim Cash, Offset Net Amounts in Consolidated Statements of Financial Condition, Assets Net Amounts in Consolidated Statements of Financial Condition, Liabilities Nature of Operations Nature of Operations [Text Block] Earnings Per Share [Abstract] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Sale of Property Sale Of Property [Member] Sale Of Property [Member] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Redeemable Convertible Preferred Shares Redeemable Convertible Preferred Shares [Member] Redeemable Convertible Preferred Shares [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] 3.875% Convertible Senior Debentures, due November 1, 2029 Three Point Eight Seven Five Percentage Convertible Senior Debentures Due Two Thousand Twenty Nine [Member] 3.875% Convertible Senior Debentures, due, 2029. Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Convertible notes interest rate Debt Instrument, Interest Rate, Stated Percentage Securities excluded from computation of earnings per share amount (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Stock repurchase program, authorized amount Stock Repurchase Program, Authorized Amount Number of shares authorized to be repurchased Stock Repurchase Program, Number of Shares Authorized to be Repurchased Number of shares repurchased during period (in shares) Stock Repurchased During Period, Shares Stock repurchased during period Stock Repurchased During Period, Value Average repurchase price per share (USD per share) Treasury Stock Acquired, Average Cost Per Share Number of common stock exchanged with related party (in shares) Related Party Transaction, Number Of Common Stock Exchanged With Related Party Related Party Transaction, Number Of Common Stock Exchanged With Related Party Number of common stock exchanged with related party, price per share (in USD per share) Related Party Transaction, Number Of Common Stock Exchanged With Related Party, Price Per Share Related Party Transaction, Number Of Common Stock Exchanged With Related Party, Price Per Share Available for future purchases Stock Repurchase Program, Remaining Authorized Repurchase Amount Banking and Thrift [Abstract] Collateralized Transactions Collateralized Financing Transactions [Text Block] Collateralized financing transactions. Variable Interest Entities Variable Interest Entity Disclosure [Text Block] Income Statement [Abstract] Statement [Table] Statement [Table] Other Product and Service, Other [Member] Statement [Line Items] Statement [Line Items] Revenues: Revenues [Abstract] Revenues Interest expense Interest Expense Expenses: Costs and Expenses [Abstract] Compensation and benefits Labor and Related Expense Cost of sales Cost of Goods and Services Sold Floor brokerage and clearing fees Floor Brokerage, Exchange and Clearance Fees Depreciation and amortization Depreciation, Depletion and Amortization Selling, general and other expenses General and Administrative Expense Total expenses Income from continuing operations before income taxes and income (loss) related to associated companies Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Income from continuing operations before income taxes Income (loss) from continuing operations Income from discontinued operations, net of income tax provision of $0, $47,045 and $118,681 Gain on disposal of discontinued operations, net of income tax provision of $0, $229,553 and $0 Net income Net loss attributable to the noncontrolling interests Gain on disposal of discontinued operations (USD per share) Amounts attributable to Jefferies Financial Group Inc. common shareholders: Income Amounts Attributable to Parent, Disclosures [Abstract] Income (loss) from continuing operations, net of taxes Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Income from discontinued operations, net of taxes Income Loss From Discontinued Operations Net Of Taxes Attributable To Parent Income Loss From Discontinued Operations Net Of Taxes Attributable To Parent Gain on disposal of discontinued operations, net of taxes Gain Loss On Disposal Of Discontinued Operations Net Of Tax Attributable To Parent Gain Loss On Disposal Of Discontinued Operations Net Of Tax Attributable To Parent Pension Plans and Postretirement Benefits Pension and Other Postretirement Benefits Disclosure [Text Block] Commitments and Contingencies Disclosure [Abstract] Future Minimum Lease Commitments for Noncancelable Operating Leases Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Schedule of commitments Contractual Obligation, Fiscal Year Maturity Schedule [Table Text Block] Schedule of Notional Amounts Associated with Derivative Contracts Meeting Definition Of Guarantee Schedule of Guarantor Obligations [Table Text Block] Fair value of securities received as collateral that may be sold or repledged 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 Loans and other receivables Fair Value, Option, Aggregate Differences, Loans and Long-term Receivables Loans and other receivables on nonaccrual status and/or 90 days or greater past due Fair Value, Option, Loans Held As Assets, Aggregate Amount In Nonaccrual Status And/Or 90 Days Or Greater Past Due, Aggregated Difference Fair Value, Option, Loans Held As Assets, Aggregate Amount In Nonaccrual Status And/Or 90 Days Or Greater Past Due, Aggregated Difference Long-term debt and short-term borrowings Fair Value, Option, Aggregate Differences, Long-term Debt And Short-term Borrowing Fair Value, Option, Aggregate Differences, Long-term Debt And Short-term Borrowing 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 Components Of Defined Benefit Pension Plans Schedule of Defined Benefit Plans Disclosures [Table Text Block] Schedule of Net Benefit Costs Schedule of Net Benefit Costs [Table Text Block] Schedule Of Amounts Recognized In Other Comprehensive Income (Loss) Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] Schedule Of Assumptions For Pension Plan Schedule of Assumptions Used [Table Text Block] Schedule Of Expected Pension Benefit Payments Schedule of Expected Benefit Payments [Table Text Block] Income Tax Disclosure [Abstract] U.S. Income (Loss) from Continuing Operations before Income Taxes, Domestic Non-U.S. Income (Loss) from Continuing Operations before Income Taxes, Foreign Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] JCP Entities JCP Entities [Member] JCP Entities [Member] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Securitization Vehicles Securitization Vehicles [Member] Securitization Vehicles [Member] Agency mortgage-backed securities Mortgage Backed Vehicles Agency [Member] Mortgage-backed vehicles - Agency. Non-agency mortgage- and other asset-backed securities Mortgage And Asset Backed Vehicles Non Agency [Member] Mortgage- and asset-backed vehicles - Non-agency. Automobile loan receivables securitized Automobile loan receivables securitized Automobile loan receivables securitized Equity commitments 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. Unfunded equity commitment related to investments Unfunded Equity Commitment Related To Investments Unfunded Equity Commitment Related To Investments Fair value of senior secured term loan receivable Fair Value of Senior Secured Term Loan Receivable Fair Value of Senior Secured Term Loan Receivable Investment in associated company Equity Method Investments Senior secured term loan receivable and investments in associated companies Senior Secured Term Loan Receivable and Loans to and Investments in Associated Companies Senior Secured Term Loan Receivable and Loans to and Investments in Associated Companies Schedule Of Loans To And Investments In Associated Companies Investment Holdings, Schedule of Investments [Table Text Block] Schedule Of Summarized Data For Investments In Associated Companies Schedule of Summarized Data for Investments in Associated Companies [Table Text Block] Schedule of Summarized Data for Investments in Associated Companies {table Text Block] Statement of Cash Flows [Abstract] Net cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by (used for) operations: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Pre-tax income from discontinued operations, including gain on disposal Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax Deferred income tax provision Deferred Income Tax Expense (Benefit), Including Discontinued Operations Deferred Income Tax Expense (Benefit), Including Discontinued Operations Recognition of accumulated other comprehensive income lodged taxes Depreciation and amortization of real estate, property, equipment and leasehold improvements Depreciation and amortization of real estate property equipment and leasehold improvements Depreciation and amortization of real estate, property, equipment and leasehold improvements. Other amortization Other Depreciation and Amortization Share-based compensation Share-based Compensation Provision for doubtful accounts Provision for Doubtful Accounts Income related to associated companies Income (Losses) Related to Associated Companies Income (Losses) Related to Associated Companies Distributions from associated companies Dividends Or Distributions From Associated Companies Dividends Or Distributions From Associated Companies Net (gains) losses related to property and equipment, and other assets Net gains losses related to property and equipment and other assets Net (gains) losses related to property and equipment, and other assets. Gain on sale of subsidiaries and associated companies Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Net change in: Increase (Decrease) in Operating Capital [Abstract] Securities deposited with clearing and depository organizations Increase (Decrease) in Securities Deposited with Clearing and Depository Organizations Increase Decrease in Securities Deposited with Clearing and Depository Organizations Trading assets Increase (Decrease) in Debt Securities, Trading, and Equity Securities, FV-NI Securities borrowed Increase (Decrease) in Securities Borrowed Securities purchased under agreements to resell Increase (Decrease) in Securities Purchased Under Agreements to Resell Increase (Decrease) in Securities Purchased Under Agreements to Resell Receivables from brokers, dealers and clearing organizations Increase (Decrease) in Receivables from Brokers-Dealers and Clearing Organizations Receivables from customers of securities operations Increase (Decrease) Receivables from Customers of Securities Operations Increase (Decrease) Receivables from Customers of Securities Operations Other receivables Increase (Decrease) in Other Receivables Other assets Increase (Decrease) In Other Assets Increase Decrease In Other Assets Trading liabilities Increase (Decrease) in Trading Liabilities Securities loaned Increase (Decrease) in Securities Loaned Transactions Securities sold under agreements to repurchase Increase (Decrease) in Payables under Repurchase Agreements Payables to brokers, dealers and clearing organizations Increase (Decrease) in Payables to Broker-Dealers and Clearing Organizations Payables to customers of securities operations Increase (Decrease) in Payables to Customers Trade payables, expense accruals and other liabilities Increase (Decrease) in Trade Payables Expense Accruals and Other Liabilities Increase (Decrease) in Trade Payables Expense Accruals and Other Liabilities Other Increase (Decrease) in Other Operating Assets and Liabilities, Net Net cash provided by (used for) operating activities - continuing operations Net Cash Provided by (Used in) Operating Activities, Continuing Operations Net cash provided by operating activities - discontinued operations Cash Provided by (Used in) Operating Activities, Discontinued Operations Net cash provided by (used for) operating activities Net Cash Provided by (Used in) Operating Activities Net cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Acquisitions of property, equipment and leasehold improvements, and other assets Payments to Acquire Property, Plant, and Equipment, and Other Assets Payments to Acquire Property, Plant, and Equipment, and Other Assets Proceeds from disposals of property and equipment, and other assets Proceeds from disposals of property and equipment, and other assets Proceeds from disposals of property and equipment, and other assets. Proceeds from sale of subsidiaries, net of expenses and cash of operations sold Proceeds From Sale Of Subsidiary, Net Of Expenses And Cash Of Operations Sold Proceeds From Sale Of Subsidiary, Net Of Expenses And Cash Of Operations Sold Proceeds from sale of associated companies Proceeds From Sale Of Associated Companies Proceeds From Sale Of Associated Companies Acquisitions, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Advances on notes, loans and other receivables Payments to Acquire Receivables Collections on notes, loans and other receivables Proceeds from Sale and Collection of Receivables Loans to and investments in associated companies Payments to Acquire Interest in Subsidiaries and Affiliates Capital distributions and loan repayment from associated companies Capital distributions and loan repayment from associated companies Capital distributions and loan repayment from associated companies. Deconsolidation of subsidiary entities Cash of subsidiary entities deconsolidated Cash of subsidiary entities deconsolidated Purchases of investments (other than short-term) Purchases of investments other than short term Purchases of investments (other than short-term). Proceeds from maturities of investments Proceeds from maturities of investments Proceeds from maturities of investments. Proceeds from sales of investments Proceeds from sales of investments Proceeds from sales of investments. Other Payments for (Proceeds from) Other Investing Activities Net cash provided by (used for) investing activities - continuing operations Net Cash Provided by (Used in) Investing Activities, Continuing Operations Net cash provided by (used for) investing activities - discontinued operations Cash Provided by (Used in) Investing Activities, Discontinued Operations Net cash provided by (used for) investing activities Net Cash Provided by (Used in) Investing Activities Net cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Issuance of debt, net of issuance costs Proceeds from Other Debt Other changes in short-term borrowings, net Proceeds from Short-term Debt Repayment of debt Repayments of Other Debt Net change in other secured financings Proceeds from other secured financings, Net Proceeds from other secured financings, net. Net change in bank overdrafts Proceeds from (Repayments of) Bank Overdrafts Issuance of common shares Proceeds from Issuance of Common Stock Net contributions from (distributions to) redeemable noncontrolling interests Net Contributions from Distributions to Redeemable Noncontrolling Interests Net Contributions from Distributions to Redeemable Noncontrolling Interests Distributions to noncontrolling interests Payments to Noncontrolling Interests Contributions from noncontrolling interests Proceeds from Noncontrolling Interests Purchase of common shares for treasury Payments for Repurchase of Common Stock Dividends paid Payments of Ordinary Dividends, Common Stock Other Proceeds from (Payments for) Other Financing Activities Net cash provided by (used for) financing activities - continuing operations Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net cash provided by (used for) financing activities - discontinued operations Cash Provided by (Used in) Financing Activities, Discontinued Operations Net cash provided by (used for) financing activities Net Cash Provided by (Used in) Financing Activities Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Change in cash classified as assets held for sale Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations 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 Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-lived Intangible Assets, Major Class Name [Domain] Exchange and clearing organization membership interests and registrations Exchange and Clearing Organization Membership Interests and Registrations [Member] Exchange and Clearing Organization Membership Interests and Registrations [Member] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Customer and other relationships Customer And Other Relationships [Member] Customer And Other Relationships [Member] Trademarks and tradename Trademarks and Trade Names [Member] Other Other Intangible Assets [Member] Real estate Real Estate Operations [Member] Real Estate Operations [Member] Other operations Other Operations [Member] Other Operations HomeFed Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Indefinite lived intangibles Indefinite-lived Intangible Assets (Excluding Goodwill) Amortizable intangibles Intangible Assets, Net (Excluding Goodwill) Goodwill Goodwill Total intangible assets, net and goodwill Intangibles, accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Intangibles recorded in connection with acquisition Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Additional goodwill generated by the establishment of deferred tax liabilities Additional Goodwill Generated By The Establishment Of Deferred Tax Liabilities Additional Goodwill Generated By The Establishment Of Deferred Tax Liabilities Deferred tax liabilities established in acquisition Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Condensed Financial Information Disclosure [Abstract] Condensed Balance Sheet Statement [Table] Condensed Balance Sheet Statement [Table] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Parent Company Parent Company [Member] Condensed Balance Sheet Statements, Captions [Line Items] Condensed Balance Sheet Statements, Captions [Line Items] Common shares, par value (USD per share) Common Stock, Par or Stated Value Per Share Common shares, authorized (in shares) Common Stock, Shares Authorized Common shares, issued and outstanding after deducting shares held in treasury (in shares) Common Stock, Shares, Outstanding Treasury stock, shares (in shares) Treasury Stock, Shares Assets And Liabilities Of Consolidated VIEs Consolidated Variable Interest Entities [Table Text Block] Consolidated Variable Interest Entities [Table Text Block] Non-Consolidated Variable Interest Entities Non Consolidated Variable Interest Entities [Table Text Block] Non-consolidated variable interest entities aggregated by principal business activity. Investments [Abstract] Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-sale [Table] U.S. government securities Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] Amortized Cost Debt Securities, Available-for-sale, Amortized Cost Gross Unrealized Gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Gross Unrealized Losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Estimated Fair Value Loans to and Investments in Associated Companies Equity Method Investments and Joint Ventures Disclosure [Text Block] Equity Method Investee Equity Method Investee [Member] Linkem Linkem [Member] Linkem [Member] Equity method investment, ownership percentage Equity Method Investment, Ownership Percentage Percentage of ownership upon conversion of preferred shares Ownership Percentage Upon Conversion Of Preferred Shares Ownership Percentage Upon Conversion of Preferred Shares Percentage of total voting securities Equity Method Investment, Voting Percentage The voting percentage of common stock or equity participation in the investee accounted for under the equity method of accounting. Shareholder loans principal outstanding Equity Method Investment, Shareholder Loans To Investee, Principal Outstanding Equity Method Investment, Shareholder Loans To Investee, Principal Outstanding Shareholder loans interest rate Related Party Transaction, Rate Derivative instrument liabilities with credit-risk-related contingent features Derivative, Net Liability Position, Aggregate Fair Value Collateral posted Collateral Already Posted, Aggregate Fair Value Collateral received Collateral Received, Aggregate Fair Value Collateral Received, Aggregate Fair Value Return of and additional collateral required in the event of a credit rating downgrade below investment grade Additional Collateral, Aggregate Fair Value Debt Disclosure [Abstract] Schedule of Short-term Debt Schedule of Short-term Debt [Table Text Block] Senior Executive Compensation Plan Senior Executive Compensation Plan [Member] Senior Executive Compensation Plan [Member] Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Restricted Stock Units with Future Service Required Restricted Stock Units With Future Service Required [Member] Restricted Stock Units With Future Service Required [Member] Restricted Stock Units with No Future Service Required Restricted Stock Units With No Future Service Required [Member] Restricted Stock Units With No Future Service Required [Member] Vested balance, beginning of period (shares) Share-Based Compensation Arrangement By Share-Based Payment Award Equity Instruments Other Than Options, Vested, Number Share-Based Compensation Arrangement By Share-Based Payment Award Equity Instruments Other Than Options, Vested, Number Distributions of underlying shares (shares) Share-Based Compensation Arrangement by Share-Based Payment Award Equity Instruments Other than Options Distributed in Period The number of shares distributed under a share based award plan made during the period on other than stock option plans. Vested balance, end of period (shares) Balance, beginning of period (USD per share) Shares-Based Compensation Arrangement by Share-Based Payment Award Equity Instruments Other than Options, Vested Weighted-Average Grant Date Fair Value Shares-Based Compensation Arrangement by Share-Based Payment Award Equity Instruments Other than Options, Vested Weighted-Average Grant Date Fair Value Distribution of underlying shares (USD per share) Share-Based Compensation Arrangement by Share-Based Payment Award Equity Instruments Other than Options Distributed in Period, Weighted-Average Exercise Price The weighted average fair value of shares distributed under share based award plan made during the period on other than Stock option plans. Balance, end of period, weighted average grant date fair value (USD per share) Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] Mortgage-backed and asset-backed securities Collateralized Mortgage Backed Securities and Asset-backed Securities [Member] Collateralized Mortgage Backed Securities and Asset-backed Securities [Member] U.S. government and federal agency securities US Government Corporations and Agencies Securities [Member] Sovereign securities Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Securities Lending Arrangements Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred Repurchase Agreements Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement Total Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement Income tax provision Discontinued Operation, Tax Effect of Income (Loss) from Discontinued Operation During Phase-out Period Gain on disposal of discontinued operations, income tax provision Discontinued Operation, Tax Effect of Gain (Loss) from Disposal of Discontinued Operation Related Party Transactions [Abstract] Related Party Transactions Related Party Transactions Disclosure [Text Block] Securities pledged Pledged Financial Instruments, Not Separately Reported, Securities Treasury stock, shares (in shares) Variable Interest Entities Variable Interest Entity, Primary Beneficiary [Member] Assets Liabilities Schedule Of Assets And Liabilities Measured On Recurring Basis At Fair Value Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Investments Measured At Fair Value Based On Net Asset Value Investments Measured At Fair Value Based On Net Asset Value [Table Text Block] Investments Measured At Fair Value Based On Net Asset Value Summary Of Changes In Fair Value Of Financial Assets And Liabilities Classified As Level 3 Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table Text Block] Reconciliation of beginning Level 3 assets and liabilities to ending Level 3 assets and liabilities (specifically disaggregating purchases, sales, settlements, issuances, transfers to Level 3 and transfers out of Level 3). Quantitative Information About Significant Unobservable Inputs Used In Level 3 Fair Value Measurements Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Summary Of Gains (Losses) Due To Changes In Instrument Specific Credit Risk For Loans and Other Receivables And Loan Commitments Measured At Fair Value Under Fair Value Option Fair Value Option, Disclosures [Table Text Block] Summary Of Amount By Which Contractual Principal Exceeds Fair Value For Loans And Other Receivables Measured At Fair Value Under Fair Value Option Schedule Of Financial Instrument Contractual Principal In Excess Of Fair Value [Table Text Block] Schedule of financial instrument contractual principal in excess of fair value. Schedule of Collateralized Financing Transactions Schedule of Collateralized Financing Transactions [Table Text Block] Schedule of Collateralized Financing Transactions [Table Text Block] Summary of Offsetting Assets Offsetting Assets [Table Text Block] Summary of Offsetting Liabilities Offsetting Liabilities [Table Text Block] Fair Value Disclosures Fair Value Disclosures [Text Block] Loss Contingencies [Table] Loss Contingencies [Table] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Jefferies Finance Jefferies Finance Llc [Member] Jefferies Finance, LLC [Member] Berkadia Berkadia [Member] Berkadia [Member] Jefferies Capital Partners LLC and Its Private Equity Funds Jefferies Capital Partners Llc And Private Equity Funds [Member] Jefferies Capital Partners LLC and Private Equity Funds [Member] Other Various Investments Other Various Investments [Member] Other Various Investments [Member] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Standby letters of credit Financial Standby Letter of Credit [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Reimbursement Of Losses Incurred, Maximum Percentage Reimbursement Of Losses Incurred, Maximum Percentage Reimbursement of losses incurred, maximum percentage. Noncancellable operating lease terms Noncancellable Operating Lease Terms Noncancellable Operating Lease Terms Rental expense (net of sublease rental income) Operating Leases, Rent Expense, Net Loan commitments outstanding to clients Outstanding Loan Commitments to Clients Outstanding Loan Commitments to Clients. Line of credit commitment to associated companies, funded portion Line of credit commitment to associated companies, funded portion. Line of credit commitment to associated companies, funded portion. Line of credit facility commitment of Jefferies Line of Credit Facility, Commitment Under Joint Venture, Entity Portion Line of Credit Facility, Commitment Under Joint Venture, Entity Portion Fair value of derivative contracts meeting the definition of a guarantee Derivative Contracts Meeting Definition of A Guarantee Derivative Contracts Meeting Definition of A Guarantee Surety policy issued Surety policy issued Surety policy issued Aggregate amount of commercial paper outstanding Commercial Paper Aggregate amount of infrastructure improvement bonds outstanding Aggregate Amount Of Infrastructure Improvement Bonds Outstanding Aggregate Amount Of Infrastructure Improvement Bonds Outstanding Letters of credit Letters of Credit Outstanding, Amount Debt instrument, term Expiration Period Expiration Period Current taxes: 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 income taxes Current Income Tax Expense (Benefit) Deferred taxes: 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 income taxes Deferred Income Tax Expense (Benefit) Total income tax provision (benefit) Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Securities purchased under agreements to resell Securities Purchased Under Agreements To Resell [Member] Securities Purchased Under Agreements To Resell [Member] Receivables Receivables [Member] Receivables [Member] Other Other Assets [Member] Other secured financings Other Secured Financings [Member] Other Secured Financings [Member] Other Other Liabilities [Member] Consolidated VIEs, asssets Variable Interest Entity, Consolidated, Carrying Amount, Assets Consolidated VIEs, liabilities Variable Interest Entity, Consolidated, Carrying Amount, Liabilities Consolidated VIEs liabilities, eliminated in consolidation Variable Interest Entity, Consolidated, Carrying Amount, Liabilities, Eliminated In Consolidation Variable Interest Entity, Consolidated, Carrying Amount, Liabilities, Eliminated In Consolidation Net Capital Requirements Regulatory Capital Requirements Disclosure [Text Block] Regulatory capital requirements disclosure. Methods And Assumptions Used To Estimate The Fair Values Other Fair Value Information [Table Text Block] Other Fair Value Information [Table Text Block] 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] Accounting Standards Update 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] Operating lease, ROU assets Operating Lease, Right-of-Use Asset Operating lease, liabilities Operating Lease, Liability 2020 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2021 Operating Leases, Future Minimum Payments, Due in Two Years 2022 Operating Leases, Future Minimum Payments, Due in Three Years 2023 Operating Leases, Future Minimum Payments, Due in Four Years 2024 Operating Leases, Future Minimum Payments, Due in Five Years Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Future minimum annual rentals Operating Leases, Future Minimum Payments Due Less: sublease income Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals