Fair Value Disclosures [Abstract] Statement [Table] Statement [Table] Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Disclosure Items [Axis] Fair Value, Hierarchy [Axis] Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Disclosure Items [Domain] Fair Value Hierarchy [Domain] Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Statement [Line Items] Statement [Line Items] Cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Deferred compensation asset Cash Surrender Value, Fair Value Disclosure Deferred compensation obligation Obligations, Fair Value Disclosure Discontinued Operation, Additional Disclosures [Abstract] Schedule of Discontinued Operations Income Statement Disclosures [Table Text Block] Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures [Table Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Scenario, Forecast [Member] Scenario, Forecast [Member] Adjustments to Additional Paid in Capital, Stock Split Net loss Net Income (Loss) Attributable to Parent Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Long-Term Debt Long-term Debt, Excluding Current Maturities Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Maximum Borrowing Capacity NYSE Minimum 30 Day Average Closing Price NYSE Minimum 30 Day Average Closing Price NYSE Minimum 30 Day Average Closing Price Segment Reporting Information, Revenue for Reportable Segment [Abstract] Segment Reporting Information Schedule of Segment Reporting Information, by Segment [Table Text Block] Inventory, Net [Abstract] Inventories Inventory Disclosure [Text Block] Preferred stock dividend rate Preferred Stock, Dividend Rate, Percentage Liquidation value, per share Preferred Stock, Liquidation Preference Per Share Deferred Revenue and Credits, Current [Abstract] Deferred revenue Deferred Revenue Advances from customers Customer Advances, Current Total Deferred Revenue and Credits, Current Deferred costs associated with deferred revenue Other Deferred Costs, Net Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Earnings Per Share [Abstract] Net (loss) from continuing operations Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest Net income (loss) from discontinued operations Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Net income (loss) Net (loss) from continuing operations - if converted Net income (loss) from continuing operations - if converted Net income (loss) from continuing operations - if converted Net income from discontinued operations - if converted Net income (loss) from discontinued operations - if converted Net income (loss) from discontinued operations - if converted Net (loss) - if converted Net Income (Loss) Attributable to Parent, Diluted Weighted average common shares Weighted Average Number of Shares Issued, Basic Less: Weighted average unvested restricted stock Weighted Average Number of Shares, Restricted Stock Denominator for basic calculation Weighted Average Number of Shares Outstanding, Basic Convertible notes Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities Convertible preferred stock - equivalent common shares Total Common Shares Attributable To Conversion Of Debt Securities Total Common Shares Attributable To Conversion Of Debt Securities Convertible preferred stock - less: share issuance limitation Unallowable Common Shares Attributable To Conversion Of Debt Securities Unallowable Common Shares Attributable To Conversion Of Debt Securities Convertible preferred stock - net allowable shares Incremental Common Shares Attributable to Dilutive Effect of Conversion of Preferred Stock Subtotal Unadjusted weighted average effect of dilutive securities Unadjusted weighted average effect of dilutive securities Less: shares excluded in a period of net loss or antidilution Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Denominator for diluted calculation Weighted Average Number of Shares Outstanding, Diluted Net income (loss) from continuing operations per share – basic and diluted Income (Loss) from Continuing Operations, Per Basic and Diluted Share Net income per share from discontinued operations - basic and diluted Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic and Diluted Share Net income (loss) per share – basic and diluted Earnings Per Share, Basic and Diluted Net Income (Loss) Per Share Earnings Per Share [Text Block] Schedule of Deferred Revenue and Advances from Customers Deferred Revenue, by Arrangement, Disclosure [Table Text Block] Property, Plant and Equipment [Abstract] Schedule of Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Construction in Progress [Member] Construction in Progress [Member] Leasehold Improvements [Member] Leasehold Improvements [Member] Machinery and Equipment [Member] Machinery and Equipment [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Property, Plant and Equipment, Gross Property, Plant and Equipment, Gross Property, Plant and Equipment, Additions Property, Plant and Equipment, Additions Property, Plant and Equipment, Transfers and Changes Property, Plant and Equipment, Transfers and Changes Property, Plant and Equipment, Disposals Property, Plant and Equipment, Disposals Property, Plant and Equipment, Gross Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Depreciation Depreciation Accumulated Depreciation, Depletion and Amortization, Sale or Disposal of Property, Plant and Equipment Accumulated Depreciation, Depletion and Amortization, Sale or Disposal of Property, Plant and Equipment Other Depreciation and Amortization Other Depreciation and Amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property, Plant and Equipment, Net Property, Plant and Equipment, Net Property, Plant And Equipment, Net Capital Expenditures Property, Plant And Equipment, Net Capital Expenditures Property, Plant And Equipment, Net Capital Expenditures Accumulated Depreciation, Depletion and Amortization, Write-down of Property, Plant and Equipment Impairment of Long-Lived Assets Held-for-use Asset Retirement Charges Production Related Impairments or Charges Property, Plant and Equipment, Net Fair Value Measurements Fair Value Disclosures [Text Block] Statement of Cash Flows [Abstract] Cash Flows from Operating Activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Adjustments to reconcile net (loss) to net cash provided by (used in) operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Transfers and retirements of machinery and equipment Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Deferred income taxes Deferred Income Tax Expense (Benefit) Other non-cash income on release of disposal obligation Other Noncash Income Convertible preferred stock dividends payable-in-kind Other Noncash Income (Expense) Gain on sale of subsidiary Gain (Loss) on Disposition of Business Inventory valuation adjustments Other Noncash Expense Changes in operating assets and liabilities: Increase (Decrease) in Operating Liabilities [Abstract] Accounts receivable – (increase) Increase (Decrease) in Accounts Receivable Inventories, net – (increase) decrease Increase (Decrease) in Inventories Payables under Russian Contract – increase Increase (Decrease) in Accounts Payable, Trade Deferred revenue, net of deferred costs – increase Increase (Decrease) in Deferred Revenue Accounts payable and other liabilities – increase (decrease) Increase (Decrease) in Accounts Payable and Accrued Liabilities Accrued depleted uranium disposition – increase (decrease) Increase (Decrease) in Other Accrued Liabilities Other, net Increase (Decrease) in Other Operating Assets and Liabilities, Net Net Cash Provided by (Used in) Operating Activities Net Cash Provided by (Used in) Operating Activities Cash Flows Provided by Investing Activities Net Cash Provided by (Used in) Investing Activities [Abstract] Capital expenditures Payments to Acquire Productive Assets Deposits for surety bonds - net (increase) decrease Increase (Decrease) in Restricted Cash Proceeds from sale of subsidiary Proceeds from Divestiture of Businesses Net Cash Provided by Investing Activities Net Cash Provided by (Used in) Investing Activities Cash Flows Used in Financing Activities Net Cash Provided by (Used in) Financing Activities [Abstract] Borrowings under revolving credit facility Proceeds from Lines of Credit Repayments under revolving credit facility Repayments of Lines of Credit Repayment of credit facility term loan Repayments of Debt, Maturing in More than Three Months Payments for deferred financing costs Payments of Financing Costs Common stock issued (purchased), net Proceeds from (Repurchase of) Equity Net Cash (Used in) Financing Activities Net Cash Provided by (Used in) Financing Activities Net Increase (Decrease) Cash and Cash Equivalents, Period Increase (Decrease) Cash and Cash Equivalents at Beginning of Period Cash and Cash Equivalents at End of Period Supplemental Cash Flow Information: Supplemental Cash Flow Information [Abstract] Interest paid Interest Paid, Net Income taxes paid, net of refunds Income Taxes Paid Separative work units inventory Separative work units inventory Carrying amount as of the balance sheet date of separative work unit ("SWU") inventory. SWU is held as the SWU component of low enriched uranium. A SWU is the standard measure of uranium enrichment using a standard formula derived from the physics of enrichment. SWU costs are based on production costs and purchase costs. SWU inventory is valued at the lower of cost or market. Uranium inventory Uranium Inventory Carrying amount as of the balance sheet date of uranium inventory. Uranium is held in the form of natural uranium and as the uranium component of low enriched uranium. Uranium inventory is valued at the lower of cost or market. Materials and supplies Other Inventory, Supplies, Gross Inventories Inventory, Net Separative work units owed to customers and suppliers Separative work units owed to customers and suppliers Separative work units owed to customers and suppliers Uranium owed to customers and suppliers Uranium owed to customers and suppliers Uranium owed to customers and suppliers Inventories owed to customers and suppliers Inventories owed to customers and suppliers Cost of SWU and uranium inventories owed related to the transfer of title from USEC to customer at fabricator whereby fabricator has elected to order less material from USEC than is required. Amounts owed are satisfied when fabricator orders future bulk deliveries. Separative work units net of liability Separative work units net of liability Separative work units inventory net of liability Uranium inventory net of liability Uranium inventory net of liability Uranium inventory net of liability Inventories, net Inventory net of Liability Inventory net of Liability Inventories provided by customers and suppliers Inventories Provided by Customers and Suppliers Uranium held by USEC to which title was held by customers and suppliers and for which no assets or liabilities were recorded on the balance sheet Decline in Uranium Spot Price Indicator Decline in Uranium Spot Price Indicator Decline in Uranium Spot Price Indicator Decline in Uranium Quantities Provided by Customers and Suppliers Decline in Uranium Quantities Provided by Customers and Suppliers Decline in Uranium Quantities Provided by Customers and Suppliers Schedule of Net Income Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Securities Excluded from Net Income Per Share Schedule of Securities Excluded from Net Income Per Share [Table Text Block] [Table Text Block] for Schedule of Securities Excluded from Net Income Per Share [Table] Accounts Receivable, Net, Current [Abstract] Schedule of Accounts Receivable Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Property, Plant and Equipment Property, Plant and Equipment [Table Text Block] Line of Credit Facility [Abstract] Schedule of Credit Facility Schedule of Line of Credit Facilities [Table Text Block] Summary of Deferred Financing Costs Summary of Deferred Financing Costs Summary of Deferred Financing Costs Statement of Comprehensive Income [Abstract] Gain arising during the period (Note 11) Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax Amortization of actuarial (gains) losses, net (Note 11) Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax Amortization of prior service costs (Note 11) Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), before Tax Other comprehensive income, before tax Other Comprehensive Income (Loss), before Tax Income tax expense related to items of other comprehensive income Other Comprehensive Income (Loss), Tax Other comprehensive income, net of tax Other Comprehensive Income (Loss), Net of Tax Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance Accumulated Other Comprehensive Income (Loss), Net of Tax Gain arising during the period Total reclassifications for the period, before tax Other comprehensive income, net of tax Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance Schedule of Financial Instruments Recorded at Fair Value Fair Value, Measurement Inputs, Disclosure [Text Block] Schedule of Fair Value of Debt Fair Value of Debt Table Text Block Fair Value of Debt Table Text Block Credit facility term loan Short-term Bank Loans and Notes Payable Credit facility term loan, fair value Loans Payable, Fair Value Disclosure Convertible preferred stock Other Long-term Debt, Current Convertible preferred stock, fair value Notes Payable, Fair Value Disclosure Convertible senior notes Convertible Debt, Noncurrent Convertible senior notes, fair value Convertible Debt, Fair Value Disclosures Deferred Revenue and Advances From Customers Deferred Revenue Disclosure [Text Block] Share-based Compensation [Abstract] Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Restructuring and Related Activities [Abstract] Schedule of Restructuring and Related Costs [Table] Schedule of Restructuring and Related Costs [Table] Restructuring Type [Axis] Restructuring Type [Axis] Type of Restructuring [Domain] Type of Restructuring [Domain] Workforce Reduction Phase One [Member] Workforce Reduction Phase One [Member] Workforce Reduction Phase One [Member] Workforce Reduction Phase Two [Member] Workforce Reduction Phase Two [Member] Workforce Reduction Phase Two [Member] Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Uranium Market Conditions [Member] Uranium Market Conditions [Member] Uranium Market Conditions [Member] Residual Uranium [Member] Residual Uranium [Member] Residual Uranium [Member] Materials and Supplies [Member] Materials and Supplies [Member] Materials and Supplies [Member] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Inventory Valuation Adjustments Inventory Write-down Non-production expenses Other Cost of Operating Revenue Site expenses Cost of Other Property Operating Expense Power Contract Losses Gain (Loss) on Sale of Commodity Contracts Accelerated property, plant and equipment expenses Accelerated propery, plant and equipment expenses Accelerated propery, plant and equipment expenses Net defined benefit plan costs for former Portsmouth employees NetDefinedBenefitPlanCostsForFormerPortsmouthEmployees Net Defined Benefit Plan Costs For Former Portsmouth Employees charged directly to cost of sales. One-time termination benefit costs Severance Costs Payments for one-time termination benefits Payments for Restructuring Estimated Near-Term Termination Benefit Costs Estimated Near-Term Termination Benefit Costs Estimated Near-Term Termination Benefit Costs Estimated Total Paducah Termination Benefit Costs Estimated Total Paducah Termination Benefit Costs Estimated Total Paducah Termination Benefit Costs DOE Share of Paducah Termination Benefit Costs DOE Share of Paducah Termination Benefit Costs DOE Share of Paducah Termination Benefit Costs Structuring advisory costs Other Restructuring Costs Curtailment (gains) Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments Schedule of Stock-Based Compensation Costs Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Other (income) Other Operating Income Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Convertible Debt [Member] Convertible Debt [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Interest expense Interest Expense, Debt Maximum percentage of common stock shares for preferred stock conversion Maximum percentage of common stock shares for preferred stock conversion Maximum percentage of common stock shares for preferred stock conversion under NYSE rules prior to shareholder approval Maximum number of common stock shares for preferred stock conversion Maximum number of common stock shares for preferred stock conversion Maximum number of common stock shares for preferred stock conversion under NYSE rules prior to obtaining shareholder approval Options excluded from diluted net income per share Options with exercise price greater than market price Options with exercise price greater than market price Warrants excluded from diluted net income per share Warrants with exercise price greater than market price Warrants with exercise price greater than market price Exercise price of excluded options Investment Options, Exercise Price Exercise price of excluded warrants Investment Warrants, Exercise Price Research and Development [Abstract] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Government [Member] Government [Member] RD&D Program Qualifying Expenditures - DOE Share Maximum funding for RD&D Program Maximum funding for RD&D Program Maximum funding for RD&D Program Maximum funding for RD&D Program - Revised Estimate Maximum funding for RD&D Program - Revised Estimate Maximum funding for RD&D Program - Revised Estimate Annual Rate of Authorized Government RD&D Program Funding Annual Rate of Authorized Government RD&D Program Funding Annual Rate of Authorized Government RD&D Program Funding RD&D Program Funding by DOE RD&D Program Funding by DOE RD&D Program Funding by DOE RD&D Program Funding by USEC RD&D Program Funding by USEC RD&D Program Funding by DOE RD&D Program Funding by DOE To Date RD&D Program Funding by DOE To Date RD&D Program Funding by DOE To Date RD&D Program Funding by DOE - Increment 1 RD&D Program Funding by DOE - Increment 1 RD&D Program Funding by DOE - Increment 1 RD&D Program Funding by DOE - Increment 2 RD&D Program Funding by DOE - Increment 2 RD&D Program Funding by DOE - Increment 2 RD&D Program Funding by DOE - Increment 3 RD&D Program Funding by DOE - Increment 3 RD&D Program Funding by DOE - Increment 3 RD&D Program Funding by DOE - Increment 4 RD&D Program Funding by DOE - Increment 4 RD&D Program Funding by DOE - Increment 4 RD&D Program Funding by DOE - Increment 5 RD&D Program Funding by DOE - Increment 5 RD&D Program Funding by DOE - Increment 5 RD&D Program Qualifying Expenditures To Date RD&D Program Qualifying Expenditures To Date RD&D Program Qualifying Expenditures To Date RD&D Program Qualifying Expenditures To Date - DOE Share RD&D Program Qualifying Expenditures To Date - DOE Share RD&D Program Qualifying Expenditures To Date - DOE Share RD&D Program Qualifying Expenditures To Date - DOE Share - Received RD&D Program Qualifying Expenditures To Date - DOE Share - Received RD&D Program Qualifying Expenditures To Date - DOE Share - Received RD&D Program Qualifying Expenditures To Date - DOE Share - Receivable RD&D Program Qualifying Expenditures To Date - DOE Share - Receivable RD&D Program Qualifying Expenditures To Date - DOE Share - Receivable RD&D Program Funding - DOE Advance RD&D Program Qualifying Expenditures RD&D Program Qualifying Expenditures RD&D Program Qualifying Expenditures Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Current Assets Assets, Current [Abstract] Accounts receivable, net Accounts Receivable, Net, Current Inventories Other current assets Prepaid Expense and Other Assets, Current Total Current Assets Assets, Current Property, Plant and Equipment, net Other Long-Term Assets Assets, Noncurrent [Abstract] Deposits for surety bonds Deposits Assets, Noncurrent Goodwill Goodwill Other assets Other Assets, Noncurrent Total Other Long-Term Assets Assets, Noncurrent Total Assets Assets LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT) Liabilities and Equity [Abstract] Current Liabilities Liabilities, Current [Abstract] Accounts payable and accrued liabilities Accounts Payable and Accrued Liabilities, Current Payables under Russian Contract Accounts Payable, Current Inventories owed to customers and suppliers Deferred revenue and advances from customers Total Current Liabilities Liabilities, Current Other Long-Term Liabilities Other Liabilities, Noncurrent [Abstract] Postretirement health and life benefit obligations Other Postretirement Defined Benefit Plan, Liabilities, Noncurrent Pension benefit liabilities Defined Benefit Pension Plan, Liabilities, Noncurrent Other liabilities Other Liabilities, Noncurrent Total Other Long-Term Liabilities Liabilities, Noncurrent Commitments and Contingencies (Note 15) Commitments and Contingencies Stockholders’ Equity (Deficit) Stockholders' Equity Attributable to Parent Total Liabilities and Stockholders’ Equity (Deficit) Liabilities and Equity General Discussion of Pension and Other Postretirement Benefits [Abstract] Schedule of Net Benefit Costs Schedule of Net Benefit Costs [Table Text Block] Advanced Technology Costs and Other Income Research, Development, and Computer Software Disclosure [Text Block] Unrecognized compensation cost Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Weighted-average period in years of costs to be recognized Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Surrender and cancellation of unexercised stock options Surrender and cancellation of unexercised stock options Surrender and cancellation of unexercised stock options Statement of Stockholders' Equity [Abstract] Statement, Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Par Value $.10 per Share [Member] Common Stock [Member] Excess of Capital over Par Value [Member] Additional Paid-in Capital [Member] Retained Earnings (Deficit) [Member] Retained Earnings [Member] Treasury Stock [Member] Treasury Stock [Member] Accumulated Other Comprehensive Income [Member] Accumulated Other Comprehensive Income (Loss) [Member] Beginning Balance Other comprehensive income, net of tax (Note 16) Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax Restricted and other common stock issued, net of amortization Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Reverse stock split of 1 share for 25 (Note 1) Ending Balance Income Statement [Abstract] Revenue: Revenues [Abstract] Separative work units Separative work units Revenue derived from sales of the separative work unit (SWU) component of low enriched uranium (LEU). Uranium Uranium Revenue derived from sales of uranium and the uranium component of low enriched uranium (LEU). Contract services Contracts Revenue Total Revenue Revenues Cost of Sales: Cost of Revenue [Abstract] Separative work units and uranium Cost of Goods Sold Contract services Contract Revenue Cost Total Cost of Sales Cost of Revenue Gross profit (loss) Gross Profit Advanced technology costs Research and Development Expense Selling, general and administrative Selling, General and Administrative Expense Special charges for workforce reductions and advisory costs Restructuring Charges Other (income) Operating income (loss) Operating Income (Loss) Interest (income) Investment Income, Interest Income (loss) from continuing operations before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Provision (benefit) for income taxes Income Tax Expense (Benefit) Net income (loss) from continuing operations Net income (loss) Weighted-average number of shares outstanding: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted-average number of shares outstanding – basic and diluted Weighted Average Number of Shares Outstanding, Basic and Diluted Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Amount of application under DOE Loan Guarantee Program Amount of application under DOE Loan Guarantee Program Amount of application under DOE Loan Guarantee Program Potential financing from Japanese export credit agencies under discussion Potential financing from export credit agencies under discussion Potential financing from Japanese export credit agencies under discussion Minimum additional financing needed for ACP beyond DOE and Japanese Minimum additional financing needed for ACP beyond DOE and Japanese Minimum additional financing needed for ACP beyond DOE and Japanese NYSE 30-day average minimum market capitalization NYSE 30-day average minimum market capitalization NYSE 30-day average minimum market capitalization NYSE 30-Day Market Capitalization Subject to Suspension NYSE 30-Day Market Capitalization Subject to Suspension NYSE 30-Day Market Capitalization Subject to Immediate Suspension and Delisting PBGC estimate of potential Portsmouth pension liability PBGC estimate of potential Portsmouth pension liability PBGC estimate of potential Portsmouth pension liability Minimum Paducah SWU Production Under 2002 DOE-USEC Agreement Minimum Paducah SWU Production Under 2002 DOE-USEC Agreement Minimum Paducah SWU Production Under 2002 DOE-USEC Agreement Document and Entity Information Document and Entity Information Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Transition Charges Restructuring and Related Activities Disclosure [Text Block] Property, Plant and Equipment Disclosure Property, Plant and Equipment Disclosure [Text Block] Accounts Receivable Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Utility Customer Receivables Utility Customer Receivables Utility Customer Receivables DOE pro-rata share of RD&D program funding Contract Services Billed Revenue Contract Services Billed Revenue Contract Services Billed Revenue Contract Services Unbilled Revenue Contract Services Unbilled Revenue Contract Services Unbilled Revenue Contract Services Customer Receivables Contract Services Customer Receivables Contract Services Customer Receivables Accounts Receivable, Net Letters of credit outstanding, amount Letters of Credit Outstanding, Amount Available credit Line of Credit Facility, Remaining Borrowing Capacity Income Tax Disclosure [Abstract] Interim temporary timing difference in income tax calculation Interim temporary timing difference in income tax calculation Interim temporary timing difference in income tax calculation Payments of Financing Costs [Abstract] Statement, Scenario [Axis] Bank credit facilities [Member] Bank Credit Facilities [Member] Bank credit facilities [Member] Convertible notes [Member] Convertible Notes [Member] Convertible notes [Member] Deferred Finance Costs, Beginning Balance Deferred Finance Costs, Noncurrent, Net Deferred financing costs, additions Deferred financing costs, additions Deferred financing costs, additions Deferred financing costs, reductions Deferred financing costs, amortization Deferred financing costs, amortization Deferred Finance Costs, End Balance Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Segment, Discontinued Operations [Member] Discontinued Operations [Member] Contract services costs Gross profit Operating income Gain on sale of subsidiary Income before income taxes Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax Provision for income taxes Discontinued Operation, Tax Effect of Discontinued Operation Net income from discontinued operations Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Legal Entity of Counterparty, Type [Axis] Legal Entity of Counterparty, Type [Axis] Legal Entity Type of Counterparty [Domain] Legal Entity Type of Counterparty [Domain] Government - portion related to retiree benefits [Member] Government - portion related to retiree benefits [Member] Government - portion related to retiree benefits [Member] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts Receivable, Gross, Noncurrent Accounts Receivable, Gross, Noncurrent Valuation Allowances and Allowances for Doubtful Accounts Allowance for Doubtful Accounts Receivable Accounts Receivable, Net, Noncurrent Accounts Receivable, Net, Noncurrent Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plans Disclosures, Defined Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans [Domain] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] Defined Benefit Pension Plans [Member] Pension Plan, Defined Benefit [Member] Postretirement Health and Life Benefits Plans [Member] Other Postretirement Benefit Plan, Defined Benefit [Member] Service costs Defined Benefit Plan, Service Cost Interest costs Defined Benefit Plan, Interest Cost Expected return on plan assets (gains) Defined Benefit Plan, Expected Return on Plan Assets Amortization of prior service costs Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Amortization of actuarial (gains) losses, net Defined Benefit Plan, Actuarial Gain (Loss) Curtailment (gains) Net benefit costs Defined Benefit Plan, Net Periodic Benefit Cost Income Taxes Income Tax Disclosure [Text Block] Net assets and liabilities of subsidiary Net assets and liabilities of subsidiary Net assets and liabilities of subsidiary Transaction costs for sale of subsidiary Transaction costs for sale of subsidiary Transaction costs for sale of subsidiary Sale of NAC Subsidiary Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Debt instrument interest rate Debt Instrument, Interest Rate, Stated Percentage Expected defined benefit plan contributions for current fiscal year Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year Expected defined benefit plan contributions for current fiscal year under ERISA Expected defined benefit plan contributions for current fiscal year under ERISA Expected defined benefit plan contributions for current fiscal year under ERISA Expected defined benefit plan contributions for current fiscal year for non-qualified plans Expected defined benefit plan contributions for current fiscal year for non-qualified plans Expected defined benefit plan contributions for current fiscal year for non-qualified plans USEC contributions Defined Benefit Plan, Contributions by Employer Decrease in pension liability, curtailments Defined Benefit Plan, Curtailments Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets Defined Contribution Plan, Employer Matching Contribution, Percent Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Debt Debt Disclosure [Text Block] Accumulated Other Comprehensive Income (Loss) [Table Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Pension and Postretirement Health and Life Benefits Pension and Other Postretirement Benefits Disclosure [Text Block] Schedule of Inventories Schedule of Inventory, Current [Table Text Block] Restricted stock and restricted stock units Restricted Stock or Unit Expense Stock options, performance awards and other Stock or Unit Option Plan Expense Less: costs capitalized as part of inventory Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Capitalized Amount Expense included in selling, general and administrative and advanced technology costs Allocated Share-based Compensation Expense Segment Information Segment Reporting Disclosure [Text Block] Revenues [Abstract] Revenue from low enriched uranium segment Revenue from low enriched uranium segment Revenue from low enriched uranium segment LEU segment gross profit Gross Profit From Low Enriched Uranium Segment Gross Profit From Low Enriched Uranium Segment Contract services segment gross profit Contracts Gross Profit Contracts Gross Profit Gross profit Gross profits all segments Gross profits all segments