Equity Method Investments and Joint Ventures [Abstract] 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) Discontinued Operations and Disposal Groups [Abstract] Summary of results of discontinued operations Disposal Groups, Including Discontinued Operations [Table Text Block] Fair Value Disclosures [Abstract] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Corporate equity securities Equity Securities [Member] Corporate debt securities Corporate Debt Securities [Member] CDOs and CLOs Collateralized Debt Obligations and Collateralized Loan Obligations [Member] Collateralized Debt Obligations and Collateralized Loan Obligations [Member] Residential mortgage-backed securities Residential Mortgage Backed Securities [Member] Commercial mortgage-backed securities Commercial Mortgage Backed Securities [Member] Other asset-backed securities Other Asset Backed Securities [Member] Other asset-backed securities. Loans and other receivables Loans and Finance Receivables [Member] Investments at fair value Investments at Fair Value [Member] Investments at Fair Value [Member] FXCM term loan Investment in Senior Secured Term Loan [Member] Investment in Senior Secured Term Loan [Member] Loans Loans [Member] Derivatives Derivative [Member] Long-term debt Long-term Debt [Member] Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Assets: Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Beginning Balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Total gains (losses) (realized and unrealized) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Net transfers into (out of) Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net Ending Balance Fair value, Assets, change in unrealized gains/(losses) included in earnings relating to instruments still held Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Liabilities: Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Beginning Balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Total gains/ losses (realized and unrealized) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Total gains (losses) (realized and unrealized), included in earnings and OCI Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included In Earnings And Other Comprehensive Income (Loss) Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included In Earnings And Other Comprehensive Income (Loss) Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Issuances Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances Net transfers into (out of) Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Transfers, Net Ending Balance Fair value, Liabilities, change in unrealized gains/(losses) included in earnings relating to instruments still held Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss) Fair value, Liabilities, change in unrealized gains/(losses) included in other comprehensive income relating to instruments still held Fair Value, Liabilities Measured On Recurring Basis, Change In Unrealized Gain (Loss) Included In Other Comprehensive Income Fair Value, Liabilities Measured On Recurring Basis, Change In Unrealized Gain (Loss) Included In Other Comprehensive Income 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 (including securities pledged of $14,322,307 and $13,059,802): Financial Instruments, Owned, at Fair Value, by Type, Alternative [Abstract] Trading assets, at fair value 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 Receivables Receivables Receivables Intangible assets, net and goodwill Intangible Assets, Net (Including Goodwill) Deferred tax asset, net Deferred 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 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; 298,312,821 and 307,515,472 shares issued and outstanding, after deducting 18,663,425 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 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 Commitments and Contingencies Disclosure [Abstract] Schedule of Guarantor Obligations [Table] Schedule of Guarantor Obligations [Table] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Derivative contracts – non-credit related Derivative Contracts Non Credit Related [Member] Derivative contracts - non credit related. Written derivative contracts – credit related Derivative Contracts Credit Related [Member] Derivative contracts - credit related. Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Derivative Notional Amount Derivative Notional Amount [Member] Derivative Notional Amount [Member] Guarantee Obligations [Line Items] Guarantor Obligations [Line Items] 2019 Guarantees Expected To Be Due, Remainder Of Fiscal Year Guarantees with a remaining term that matures during the fiscal year. These may include derivative guarantees, etc. 2020 Guarantees Expected To Be Due In Second Year Guarantees expected to be due within 2 year. These may include, derivative guarantees, etc. 2021 and 2022 Guarantees Expected To Be Due In Three And Four Years Guarantees expected to be due within 3 to 4 fiscal years. These may include, derivative guarantees, etc. 2023 and 2024 Guarantees Expected To Be Due In Five And Six Years Guarantees expected to be due within 5 to 6 fiscal years. These may include, derivative guarantees, etc. 2025 and Later Guarantees Expected To Be Due in Seventh Year And Thereafter Guarantees expected to be due within 6 fiscal years and thereafter. These may include, derivative guarantees, etc Notional/ Maximum Payout Guarantor Obligations, Maximum Exposure, Undiscounted Variable Interest Entities [Abstract] Variable Interest Entities [Abstract] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Securitization Vehicles Securitization Vehicles [Member] Securitization Vehicles [Member] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Consolidation adjustments Consolidation, Eliminations [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Jefferies Group Jefferies Group LLC [Member] Jefferies Group LLC Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Financial instruments owned Securities purchased under agreement to resell Other Other secured financings Other Other Liabilities Secured financings eliminated in consolidation Secured financings eliminated in consolidation Secured financings eliminated in consolidation Intercompany payables Intercompany Payables Intercompany Payables 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] Notional amount Derivative, Notional Amount Segment Reporting [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Reportable Segments Operating Segments [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Merchant Banking Merchant Banking Segment [Member] Merchant Banking Segment [Member] Corporate Corporate Segment [Member] LAM and Berkadia Transferred Leucadia Asset Management And Berkadia Transferred [Member] Leucadia Asset Management And Berkadia Transferred [Member] FXCM Fxcm [Member] FXCM Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Parent Company interest Parent Company [Member] Segment Reporting Information [Line Items] Net Revenues Revenues, Net of Interest Expense Consolidated income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Depreciation and amortization Depreciation, Depletion and Amortization Principal transactions Principal Transactions Revenue, Net Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Investments [Abstract] Available for Sale Securities and Other Investments Investment Holdings [Text Block] Income Statement [Abstract] Income tax provision Discontinued Operation, Tax Effect of Income (Loss) from Discontinued Operation During Phase-out Period Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Shares $1 Par Value Common Stock [Member] Additional Paid-In Capital Additional Paid-in Capital [Member] Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Retained Earnings Retained Earnings [Member] Subtotal Parent [Member] Noncontrolling Interests Noncontrolling Interest [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning Balance Cumulative effect of the adoption of accounting standards Cumulative Effect of New Accounting Principle in Period of Adoption Beginning Balance, Adjusted Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance Net income Profit Loss Excluding Net Income Loss Attributable To Redeemable Noncontrolling Interests Profit Loss Excluding Net Income Loss Attributable To Redeemable Noncontrolling Interests Other comprehensive income, net of taxes Other Comprehensive Income (Loss), Net of Tax Contributions from noncontrolling interests Contributions from Noncontrolling Interests Contributions from Noncontrolling Interests Distributions to noncontrolling interests Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Change in interest in consolidated subsidiary Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net Share-based compensation expense Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Change in fair value of redeemable noncontrolling interests Change In Fair Value Of Redeemable Noncontrolling Interests Change In Fair Value Of Redeemable Noncontrolling Interests Purchase of common shares for treasury Treasury Stock, Value, Acquired, Cost Method Dividends Dividends, Common Stock Other Stockholders' Equity, Other Ending Balance Other Fair Value Information [Abstract] Other Fair Value Information [Abstract] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Carrying Amount Reported Value Measurement [Member] Fair Value Estimate of Fair Value Measurement [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Notes and loans receivable Notes and Loans Receivable Notes and loans receivable Statement of Cash Flows [Abstract] Net cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Adjustments to reconcile net income to net cash used for operations: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Pre-tax income from discontinued operations Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax Deferred income tax provision (benefit) Deferred Income Tax Expense (Benefit), Continuing And Discontinued Operations Deferred Income Tax Expense (Benefit), Continuing And Discontinued Operations Depreciation and amortization of property, equipment and leasehold improvements Depreciation and amortization of property equipment and leasehold improvements Depreciation and amortization of property, equipment and leasehold improvements. Other amortization Other Depreciation and Amortization 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 Including Income (Losses) Related to Subsidiary Associated Companies Primarily Classified as Revenues Income (Losses) Related to Associated Companies Including Income (Losses) Related to Subsidiary Associated Companies Primarily Classified as Revenues Distributions from associated companies Dividends Or Distributions From Associated Companies Dividends Or Distributions From Associated Companies Net losses related to property and equipment, and other assets Net gains losses related to property and equipment and other assets Net (gains) losses related to property and equipment, and other assets. Net change in: Increase (Decrease) in Operating Capital [Abstract] Securities deposited with clearing and depository organizations Increase (Decrease) in Securities Deposited with Clearing and Depository Organizations Increase Decrease in Securities Deposited with Clearing and Depository Organizations Trading assets Increase (Decrease) in Debt Securities, Trading, and Equity Securities, FV-NI Securities borrowed Increase (Decrease) in Securities Borrowed Securities purchased under agreements to resell Increase (Decrease) in Securities Purchased Under Agreements to Resell Increase (Decrease) in Securities Purchased Under Agreements to Resell Receivables from brokers, dealers and clearing organizations Increase (Decrease) in Receivables from Brokers-Dealers and Clearing Organizations Receivables from customers of securities operations Increase (Decrease) Receivables from Customers of Securities Operations Increase (Decrease) Receivables from Customers of Securities Operations Other receivables Increase (Decrease) in Other Receivables Other assets Increase (Decrease) In Other Assets Increase Decrease In Other Assets Trading liabilities Increase (Decrease) in Trading Liabilities Securities loaned Increase (Decrease) in Securities Loaned Transactions Securities sold under agreements to repurchase Increase (Decrease) in Payables under Repurchase Agreements Payables to brokers, dealers and clearing organizations Increase (Decrease) in Payables to Broker-Dealers and Clearing Organizations Payables to customers of securities operations Increase (Decrease) in Payables to Customers Trade payables, expense accruals and other liabilities Increase (Decrease) in Trade Payables Expense Accruals and Other Liabilities Increase (Decrease) in Trade Payables Expense Accruals and Other Liabilities Other Increase (Decrease) in Other Operating Assets and Liabilities, Net Net cash used for operating activities - continuing operations Net Cash Provided by (Used in) Operating Activities, Continuing Operations Net cash used for operating activities - discontinued operations Cash Provided by (Used in) Operating Activities, Discontinued Operations Net cash used for operating activities Net Cash Provided by (Used in) Operating Activities Net cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Acquisitions of property, equipment and leasehold improvements, and other assets Payments to Acquire Property, Plant, and Equipment, and Other Assets Payments to Acquire Property, Plant, and Equipment, and Other Assets Proceeds from disposals of property and equipment, and other assets Proceeds from disposals of property and equipment, and other assets Proceeds from disposals of property and equipment, and other assets. Advances on notes, loans and other receivables Payments to Acquire Receivables Collections on notes, loans and other receivables Proceeds from Sale and Collection of Receivables Loans to and investments in associated companies Payments to Acquire Interest in Subsidiaries and Affiliates Capital distributions and loan repayments from associated companies Capital distributions and loan repayments from associated companies Capital distributions and loan repayments from associated companies. Purchases of investments (other than short-term) Payments to Acquire Investments Proceeds from maturities of investments Proceeds from maturities of investments Proceeds from maturities of investments. Proceeds from sales of investments Proceeds from sales of investments Proceeds from sales of investments. Other Payments for (Proceeds from) Other Investing Activities Net cash provided by (used for) investing activities - continuing operations Net Cash Provided by (Used in) Investing Activities, Continuing Operations Net cash 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 Repayment of debt Repayments of Other Debt Net change in other secured financings Net change in other secured financings Net change in other secured financings Net change in bank overdrafts Proceeds from (Repayments of) Bank Overdrafts 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 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 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 Statement of Comprehensive Income [Abstract] Net income 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 $107 and $(370) 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 $(377) and $(5) 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 $484 and $(365) 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 $7,722 and $1,926 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 $0 and $0 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 $7,722 and $1,926 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 $5,949 and $(4,634) 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 $(99) 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 $6,048 and $(4,634) 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 $(86) and $1,234 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 (loss), net of income tax provision (benefit) of $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 $(86) and $1,234 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 $0 and $0 Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax Reclassification adjustment for pension (gains) losses included in net income, net of income tax provision (benefit) of $(119) and $(151) Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax Net change in pension liability, net of income tax provision (benefit) of $119 and $151 Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Other comprehensive income (loss), net of income taxes Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive (income) 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. Preferred stock dividends Preferred Stock Dividends, Income Statement Impact Comprehensive income attributable to Jefferies Financial Group Inc. common shareholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Securitization Activities [Abstract] Securitization Activities [Abstract] Securitization Activities [Table] Securitization Activities [Table] Securitization Activities [Table] CLOs Collateralized Loan Obligations [Member] Consumer and other loans Consumer and Other Loans [Member] Consumer and Other Loans [Member] Securitization Activities [Line Items] Securitization Activities [Line Items] U.S. government agency residential mortgage-backed securities Rmbs Securitization Assets Represents unpaid principal amount of assets in residential mortgage backed securitization vehicles at the balance sheet date. U.S. government agency commercial mortgage-backed securities Cmbs Securitization Assets Represents unpaid principal amount of assets in commercial mortgage backed securitization vehicles at the balance sheet date. CLOs Collateralized Loan Obligations Securitization Assets Collateralized Loan Obligations Securitization Assets Retained Interests Retained Interest, Fair Value Disclosure Consumer and Other Loans Securitization Assets Consumer and Other Loans Securitization Assets Consumer and Other Loans Securitization Assets Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Table] Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Table] Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Table] Commodity swaps, options and forwards Commodity Swaps Options And Forwards [Member] Commodity swaps options and forwards. Equity swaps and options Equity Swaps And Options [Member] Equity Swaps And Options [Member] Credit default swaps Total return swaps Total Return Swap [Member] Foreign currency forwards, swaps and options Foreign Currency Forwards Swaps And Options [Member] Foreign currency forwards swaps and options. Fixed income forwards Fixed Income Forwards [Member] Fixed income forwards. Interest rate swaps Interest Rate Swap [Member] Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items] Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items] Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items] OTC derivative assets having maturity period of 0 to 12 months Otc Derivative Assets Having Maturity Period Of Zero To Twelve Months Over the counter derivative assets having maturity period of zero to twelve months. OTC derivative assets having maturity period of 1 to 5 years Otc Derivative Assets Having Maturity Period Of One To Five Years OTC derivative assets having maturity period of 1 to5 years. OTC derivative assets having maturity period of greater than 5 years Otc Derivative Assets Having Maturity Period Of Greater Than Five Years OTC derivative assets having maturity period of greater than five years. OTC derivative assets cross-maturity netting Otc Derivative Assets Cross Maturity Netting OTC derivative assets cross maturity netting. Total OTC derivative assets, net of cross-maturity netting Consolidated Otc Derivative Assets Net Of Crossmaturity Netting Total OTC derivative assets, net of cross-maturity netting. Cross product counterparty netting Derivative Assets Cross Product Counterparty Netting Derivative Assets Cross Product Counterparty Netting. 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 having maturity period of 0 to 12 months Otc Derivative Liabilities Having Maturity Period Of Zero To Twelve Months OTC derivative liabilities having maturity period of zero to twelve months. OTC derivative liabilities having maturity period of 1 to 5 years Otc Derivative Liabilities Having Maturity Period Of One To Five Years OTC derivative liabilities having maturity period of 1 to 5 years. OTC derivative liabilities having maturity period of greater than 5 years Otc Derivative Liabilities Having Maturity Period Of Greater Than Five Years OTC derivative liabilities having maturity period of greater than 5 years. OTC derivative liabilities cross-maturity netting Otc Derivative Liabilities Cross Maturity Netting OTC derivative liabilities cross maturity netting. Total OTC derivative liabilities, net of cross-maturity netting Consolidated Otc Derivative Liabilities Net Of Crossmaturity Netting Total OTC derivative liabilities, net of cross-maturity netting. Cross product counterparty netting Derivative Liabilities Cross Product Counterparty Netting Derivative Liabilities Cross Product Counterparty Netting. Total OTC derivative liabilities included in Trading liabilities OTC Derivative Liabilities Included In Trading Liabilities OTC Derivative Liabilities Included In Trading Liabilities Exchange traded derivative assets and other credit agreements Exchange traded derivative assets and other credit agreements Exchange traded derivative assets and other credit agreements Cash collateral received Cash Collateral Received Cash collateral received that was netted against OTC derivative assets. Exchange traded derivative liabilities and other credit agreements Exchange traded derivative liabilities and other credit agreements Exchange traded derivative liabilities and other credit agreements Cash collateral pledged Cash collateral pledged Cash collateral pledged that was netted against OTC derivative liabilities. Other Fair Value Information Other Fair Value Information Disclosure [Text Block] Other Fair Value Information Disclosure [Text Block] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] National Beef National Beef [Member] National Beef [Member] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] 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] Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Ownership percentage Ownership Percentage Ownership Percentage Equity method investment, ownership percentage Equity Method Investment, Ownership Percentage Weighted average useful life Weighted Average Life Of Assets and Liabilities With A Basis Difference Weighted Average Life Of Assets and Liabilities With A Basis Difference Offsetting [Abstract] Financial Statement Offsetting Balance Sheet Offsetting Disclosure [Text Block] Balance Sheet Offsetting Disclosure [Text Block] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Level 3 Fair Value, Inputs, Level 3 [Member] Non-exchange-traded securities Non Exchange Traded Securities [Member] Non Exchange Traded Securities [Member] Private equity securities Private Equity Securities [Member] Private Equity Securities [Member] Measurement Input Type [Axis] Measurement Input Type [Axis] Measurement Input Type [Domain] Measurement Input Type [Domain] Price Measurement Input, Offered Price [Member] Transaction level Measurement Input, Transaction Level [Member] Measurement Input, Transaction Level [Member] Underlying stock price Measurement Input, Share Price [Member] Discount rate/yield Measurement Input, Discount Rate [Member] Estimated recovery percentage Measurement Input, Estimated Recovery Percentage [Member] Measurement Input, Estimated Recovery Percentage [Member] Constant prepayment rate Measurement Input, Prepayment Rate [Member] Constant default rate Measurement Input, Default Rate [Member] Loss severity Measurement Input, Loss Severity [Member] Cumulative loss rate Measurement Input, Cumulative Loss Rate [Member] Measurement Input, Cumulative Loss Rate [Member] Duration (years) Measurement Input, Expected Term [Member] Revenue growth Measurement Input, Long-term Revenue Growth Rate [Member] Volatility Measurement Input, Price Volatility [Member] Term based on the pay off (years) Measurement Input, Maturity [Member] Default probability Measurement Input, Default Probability [Member] Measurement Input, Default Probability [Member] Basis points Measurement Input, Basis Points [Member] Measurement Input, Basis Points [Member] Equity options Equity Option [Member] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Domain] Valuation Approach and Technique [Domain] Discounted cash flows Discounted Cash Flows [Member] Discounted Cash Flows [Member] Scenario analysis Scenario Analysis [Member] Scenario Analysis [Member] Market approach Valuation, Market Approach [Member] Contingent claims analysis Contingent Claims Analysis [Member] Contingent Claims Analysis [Member] Option model/default rate Option Model / Default Rate [Member] Option Model / Default Rate [Member] Volatility benchmarking Volatility Benchmarking [Member] Volatility Benchmarking [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Weighted Average Weighted Average [Member] Trading assets, fair value Trading Assets, At Fair Value Trading Assets, At Fair Value Trading assets, measurement input Trading Assets, Measurement Input Trading Assets, Measurement Input Trading assets, measurement input, term Trading Assets, Measurement Input, Term Trading Assets, Measurement Input, Term Derivative assets Derivative Asset Derivative asset, measurement input Derivative Asset, Measurement Input Debt instrument, fair value Debt Instrument, Fair Value Disclosure Debt instrument, measurement input Debt Instrument, Measurement Input Derivative liability Derivative Liability Derivative liability, measurement input Derivative Liability, Measurement Input Long-term debt, fair value Long-term Debt, Fair Value Long-term debt, measurement input Long-term Debt, Measurement Input Temporary Equity Disclosure [Abstract] Redeemable Noncontrolling Interest, by Legal Entity [Table] Redeemable Noncontrolling Interest, by Legal Entity [Table] Redeemable Noncontrolling Interest [Line Items] Redeemable Noncontrolling Interest [Line Items] Redeemable Noncontrolling Interest [Roll Forward] Redeemable Noncontrolling Interest [Roll Forward] Redeemable Noncontrolling Interest [Roll Forward] Beginning balance Income allocated to redeemable noncontrolling interests Net Income (Loss) Attributable to Redeemable Noncontrolling Interest Distributions to redeemable noncontrolling interests Payments for Distributions To Redeemable Noncontrolling Interests Payments for Distributions To Redeemable Noncontrolling Interests Decrease in fair value of redeemable noncontrolling interests Ending balance Goodwill and Intangible Assets Disclosure [Abstract] Remainder of current year Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Five 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 Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] HRG Hrg Group [Member] HRG Group [Member] Spectrum Brands Spectrum Brands Holdings, Inc. [Member] Spectrum Brands Holdings, Inc. [Member] Fiesta Restaurant Group, Inc. Fiesta Restaurant Group, Inc. [Member] Fiesta Restaurant Group, Inc. [Member] HRG Group/Spectrum Brands Holdings, Inc. HRG Group/Spectrum Brands Holdings, Inc. [Member] HRG Group/Spectrum Brands Holdings, Inc. [Member] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Loans and other receivables on nonaccrual status and/or 90 days or greater past due Fair Value, Option, Loans Held As Assets, Aggregate Amount In Nonaccrual Status And/Or 90 Days Or Greater Past Due Fair Value, Option, Loans Held As Assets, Aggregate Amount In Nonaccrual Status And/Or 90 Days Or Greater Past Due Loans and other receivables 90 days or greater past due Fair Value, Option, Loans Held as Assets, 90 Days or More Past Due Shares owned, number Investment Owned, Balance, Shares Percentage of outstanding common stock owned Percentage of Shares Owned Percentage of Shares Owned Financial instruments owned trading assets, at fair value Cash consideration paid for shares Cash consideration paid for shares Cash consideration paid for shares Changes in fair value of investments reflected as principal transactions Changes in Fair Value of Investments Reflected as Principal Transactions Changes in Fair Value of Investments Reflected as Principal Transactions Revenue of investee Investment, Summarized Financial Information of Investee, Revenue Investment, Summarized Financial Information of Investee, Revenue Net income (loss) from continuing operations of investee Investment, Summarized Financial Information of Investee, Net Income (Loss) from Continuing Operations Investment, Summarized Financial Information of Investee, Net Income (Loss) from Continuing Operations Net income (loss) of investee Investment, Summarized Financial Information of Investee, Net Income (Loss) Including Portion Attributable to Noncontrolling Interest Investment, Summarized Financial Information of Investee, Net Income (Loss) Including Portion 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and other expenses General and Administrative Expense Total expenses Costs and Expenses Income from continuing operations before income taxes and income related to associated companies Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Income related to associated companies Income (Loss) from Equity Method Investments Income from continuing operations before income taxes Income tax provision (benefit) Income Tax Expense (Benefit) Income from continuing operations Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Income from discontinued operations, net of income tax provision of $0 and $15,934 Net income Net (income) loss attributable to the noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Net (income) loss attributable to the redeemable noncontrolling interests Net income attributable to Jefferies Financial Group Inc. common shareholders Net Income (Loss) Attributable to Parent Basic earnings per common share attributable to Jefferies Financial Group Inc. common shareholders: Earnings Per Share, Basic [Abstract] Income from continuing operations (in dollars per share) Income (Loss) from Continuing Operations, Per Basic Share Income from discontinued operations (in dollars per share) Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share Net income (in dollars per share) Earnings Per Share, Basic Diluted earnings per common share attributable to Jefferies Financial Group Inc. common shareholders: Earnings Per Share, Diluted [Abstract] Income from continuing operations (in dollars per share) Income (Loss) from Continuing Operations, Per Diluted Share Income from discontinued operations (in dollars per share) Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share Net income (in dollars per share) Earnings Per Share, Diluted Amounts attributable to Jefferies Financial Group Inc. common shareholders: Net Income (Loss) Attributable to Parent [Abstract] Income 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 Tax, Attributable to Parent Investments In Associated Companies [Table] Investments In Associated Companies [Table] Investments In Associated Companies [Table] Disposal group, disposed of by sale, not discontinued operations Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Garcadia companies Garcadia [Member] Garcadia Jefferies Finance Jefferies Finance Llc [Member] Jefferies Finance, LLC [Member] Berkadia Berkadia [Member] Berkadia [Member] Linkem Linkem [Member] Linkem [Member] HomeFed Homefed Corporation [Member] HomeFed Corporation - Member Other Associated Companies Other [Member] Associated Companies Other [Member] Investments In Associated Companies [Line Items] Investments In Associated Companies [Line Items] Investments In Associated Companies [Line Items] Loans to and Investments in Associated Companies Rollforward [Roll Forward] Loans to and Investments in Associated Companies Rollforward [Roll Forward] Loans to and Investments in Associated Companies Rollforward [Roll Forward] Loans to and investments in associated companies, beginning balance Equity Method Investments Income (losses) related to associated companies Income (losses) related to Jefferies associated companies Equity Method Investments, Income (Losses) Related to Subsidiary Associated Companies Primarily Classified as Revenues Equity Method Investments, Income (Losses) Related to Subsidiary Associated Companies Primarily Classified as Revenues Contributions to (distributions from) associated companies, net Equity Method Investments, Contributions to (Distributions From) Associated Companies, Net Equity Method Investments, Contributions to (Distributions From) Associated Companies, Net Other Equity Method Investments, Other Activity, Net Equity Method Investments, Other Activity, Net Loans to and investments in associated companies, ending balance Percentage of equity method investment for sale Equity Method Investment, Percentage Of Interest Sold Equity Method Investment, Percentage Of Interest Sold Fair Value And Related Number Of Derivative Contracts Categorized By Predominant Risk Exposure Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Unrealized And Realized Gains (Losses) On Derivative Contracts Derivative Instruments, Gain (Loss) [Table Text Block] Remaining Contract Maturity Of Fair Value Of OTC Derivative Assets And Liabilities Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Table Text Block] OTC derivatives by risk exposure and maturity profile. Counterparty Credit Quality With Respect To Fair Value Of OTC Derivatives Assets Counterparty Credit Quality With Respect To Fair Value Of Otc Derivatives Assets [Table Text Block] Counterparty credit quality with respect to the fair value of OTC derivatives assets. Credit Related Derivative Contracts Disclosure of Credit Derivatives [Table Text Block] Derivative Instruments With Contingent Features Derivative Instruments With Contingent Features [Table Text Block] Derivative Instruments With Contingent Features [Table Text Block] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] Securities or Other Assets Sold under Agreements to Repurchase, Maturity Periods [Axis] Repurchase Agreements and Similar Transactions, Maturity Periods [Axis] Assets Sold under Agreements to Repurchase, Maturity Period [Domain] Repurchase Agreements and Similar Transactions, Maturity Periods [Domain] Overnight and Continuous Maturity Overnight [Member] Up to 30 Days Maturity Less than 30 Days [Member] 30 to 90 Days Maturity 30 to 90 Days [Member] Greater than 90 Days Maturity Greater than 90 Days [Member] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Securities lending arrangements Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred Repurchase agreements Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement Total Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement Schedule Of Assets And Liabilities Measured On Recurring Basis At Fair Value Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Investments Measured At Fair Value Based On Net Asset Value Investments Measured At Fair Value Based On Net Asset Value [Table Text Block] Investments Measured At Fair Value Based On Net Asset Value Summary Of Changes In Fair Value Of Financial Assets And Liabilities Classified As Level 3 Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table Text Block] Reconciliation of beginning Level 3 assets and liabilities to ending Level 3 assets and liabilities (specifically disaggregating purchases, sales, settlements, issuances, transfers to Level 3 and transfers out of Level 3). Quantitative Information About Significant Unobservable Inputs Used In Level 3 Fair Value Measurements Fair Value Inputs Assets And Liabilities Quantitative Information [Table Text Block] Tabular disclosure of quantitative information about significant unobservable inputs used in the fair value measurement of Level 3 financial assets and liabilities, including valuation technique and range of inputs Summary Of Gains (Losses) Due To Changes In Instrument Specific Credit Risk For Loans and Other Receivables And Loan Commitments Measured At Fair Value Under Fair Value Option Fair Value Option, Disclosures [Table Text Block] Summary Of Amount By Which Contractual Principal Exceeds Fair Value For Loans And Other Receivables Measured At Fair Value Under Fair Value Option Schedule Of Financial Instrument Contractual Principal In Excess Of Fair Value [Table Text Block] Schedule of financial instrument contractual principal in excess of fair value. 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Unfunded equity commitment related to investments Unfunded Equity Commitment Related To Investments Unfunded Equity Commitment Related To Investments Carrying Amount Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Designated as Accounting Hedges Designated as Hedging Instrument [Member] Not Designated as Accounting Hedges 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 Contracts [Member] Credit Contracts [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 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Type [Domain] Assets Sold under Agreements to Repurchase, Type [Domain] Trading Liabilities Trading Liabilities [Member] Financial Instruments [Line Items] Financial Instruments [Line Items] Loans and other receivables 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 Comprehensive Income (Loss), Financial Liability, Fair Value Option, Unrealized Gain (Loss) Arising During Period, before Tax Other changes in fair value Fair Value, Option, Changes in Fair Value, Gain (Loss) Loans and other receivables Fair Value, Option, Aggregate Differences, Loans and Long-term Receivables Loans and other receivables on nonaccrual status and/or 90 days or greater past due Fair Value, Option, Loans Held As Assets, Aggregate Amount In Nonaccrual Status And/Or 90 Days Or Greater Past Due, Aggregated Difference Fair Value, Option, Loans Held As Assets, Aggregate Amount In Nonaccrual Status And/Or 90 Days Or Greater Past Due, Aggregated Difference Long-term debt Fair Value, Option, Aggregate Differences, Long-term Debt Fair Value, Option, Aggregate Differences, Long-term Debt All loans and other receivables 90 days or greater past due Fair Value, Option, Loans Held as Assets, 90 Days or More Past Due, Aggregate Difference Commitments, Contingencies And Guarantees Commitments Contingencies and Guarantees [Text Block] Schedule Of Redeemable Noncontrolling Interests Schedule of Redeemable Noncontrolling Interests [Table Text Block] Schedule of Redeemable Noncontrolling Interests [Table Text Block] Related Party Transactions [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Payables, expense accruals and other liabilities Payables, Expense Accruals And Other Liabilities [Member] Payables, Expense Accruals And Other Liabilities [Member] Private Equity Related Funds Private Equity Related Funds [Member] Private Equity Related Funds Affiliated Entity Affiliated Entity [Member] Officers and Employees Officers and Employees [Member] Officers and Employees [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Loans to and/or equity investments in related funds Loans to and/or equity investments in related funds Loans to and/or equity investments in related funds Net gains (losses) from private equity related funds Income (Loss) from private equity related funds Income (loss) from private equity related funds Purchase commitment Purchase Commitments Outstanding Purchase Commitments Outstanding OTC foreign exchange contracts Foreign Currency Contracts, Liability, Fair Value Disclosure Loans outstanding to related party Loans and Leases Receivable, Related Parties Income Taxes [Table] Income Taxes [Table] Income Taxes [Table] Income Taxes [Line Items] Income Taxes [Line Items] Unrecognized tax benefits Unrecognized Tax Benefits Interest included in unrecognized tax benefits Unrecognized Tax Benefits, Interest on Income Taxes Accrued Tax Cuts and Jobs Act of 2017, measurement period adjustment, income tax benefit Tax Cuts And Jobs Act of 2017, Measurement Period Adjustment, Income Tax Expense (Benefit) Tax Cuts And Jobs Act of 2017, Measurement Period Adjustment, Income Tax Expense (Benefit) Provision for income taxes Effective tax rate Effective Income Tax Rate Reconciliation, Percent Decrease of income tax provision Income Tax Expense (Benefit) From Reversal of Valuation Allowance Income Tax Expense (Benefit) From Reversal of Valuation Allowance Net Capital Requirements [Abstract] Net Capital Requirements [Abstract] Net Capital Requirements [Table] Net Capital Requirements [Table] Net Capital Requirements [Table] Jefferies LLC Jefferies LLC [Member] Jefferies LLC [Member] Net Capital Requirements [Line Items] Net Capital Requirements [Line Items] Net Capital Requirements [Line Items] Net Capital Net Capital Excess Net Capital Alternative Excess Net Capital Schedule of Available for Sale Securities Debt Securities, Available-for-sale [Table Text Block] Debt Disclosure [Abstract] Short-Term Borrowings Short-term Debt [Text Block] Schedule Of Commitments And Guarantee Obligations [Table] Schedule Of Commitments And Guarantee Obligations [Table] Schedule Of Commitments And Guarantee Obligations [Table] Equity commitments Equity Commitments [Member] Equity commitments. Loan commitments Loan Commitments [Member] Loan 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 Unfunded Commitments [Member] Other unfunded commitments [Member] Forward starting securities purchased under agreements to resell settled Forward Starting Securities Purchased Under Agreements To Resell Settled [Member] Forward Starting Securities Purchased Under Agreements To Resell Settled [Member] Forward starting securities purchased under agreements to repurchase settled Forward Starting Securities Purchased Under Agreements To Repurchase Settled [Member] Forward Starting Securities Purchased Under Agreements To Repurchase Settled [Member] Commitments And Guarantee Obligations [Line Items] Commitments And Guarantee Obligations [Line Items] Commitments And Guarantee Obligations [Line Items] 2019 Contractual Obligation, Future Minimum Payments Due, Remainder of Fiscal Year 2020 Contractual Obligation, Due in Second Year 2021 and 2022 Contractual Obligation, Due In Third And Fourth Years Commitments and guarantees expected to be due within 3 to 4 fiscal years. These may include, equity, loan, mortgage-related and underwriting commitments, derivative guarantees, etc. 2023 and 2024 Contractual Obligation, Due In Fifth And Sixth Years Commitments and guarantees expected to be due within 5 to 6 fiscal years. These may include, equity, loan, mortgage-related and underwriting commitments, derivative guarantees, etc. 2025 and Later Contractual Obligation, Due In Seventh Year And Thereafter Commitments and guarantees expected to be due within 7 fiscal years and thereafter. These may include, equity, loan, mortgage-related and underwriting commitments and derivative guarantees, etc. Maximum Payout Contractual Obligation Guarantor obligation settled period Repos Obligation Settlement Period Repos Obligation Settlement Period Marfrig Global Foods S.A. Marfrig Global Foods S.A. [Member] Marfrig Global Foods S.A. [Member] Cash from sale of subsidiary Proceeds from Divestiture of Businesses Ownership percentage to be acquired further from other equity owners Ownership Percentage Acquired From Other Equity Owners Ownership Percentage Acquired From Other Equity Owners Lockup period related to divestiture of businesses Lockup Period Related To Divestiture Of Businesses Lockup Period Related To Divestiture Of Businesses Income from discontinued operations before income taxes Income (Loss) From Discontinued Operations, Before Tax, Attributable To Parent Income (Loss) From Discontinued Operations, Before Tax, Attributable To Parent Distributions received Proceeds From Equity Method Investment Distribution Amount of distribution received from equity method investee for return on investment, classified as operating activities AND distribution for return of investment, classified as investing activities. Earnings Per Share [Table] Earnings Per Share [Table] Earnings Per Share [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Restricted Stock with Future Service Required Restricted Stock With Future Service Required [Member] Restricted Stock With Future Service Required [Member] Restricted Stock Units with No Future Service Required Restricted Stock Units With No Future Service Required [Member] Restricted Stock Units With No Future Service Required [Member] Stock options Employee Stock Option [Member] Restricted Stock Units Restricted Stock Units (RSUs) [Member]