Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2013
Summary of Significant Accounting Policies [Abstract]
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents Cash and cash equivalents include temporary cash investments with original maturities of three months or less.
Inventory, Policy [Policy Text Block]	Inventories and Inventories Owed to Customers and Suppliers USEC holds uranium in the form of natural uranium and as the uranium component of LEU. USEC holds SWU as the SWU component of LEU. USEC may also hold title to the uranium and SWU components of LEU at fabricators to meet book transfer requests by customers. Fabricators process LEU into fuel for use in nuclear reactors. Under inventory optimization arrangements between USEC and domestic fabricators, fabricators order bulk quantities of LEU from USEC based on scheduled or anticipated orders from utility customers for deliveries in future periods. As delivery obligations under actual customer orders arise, USEC satisfies these obligations by arranging for the transfer to the customer of title to the specified quantity of LEU at the fabricator. USEC’s balances of SWU and uranium vary over time based on the timing and size of the fabricator’s LEU orders from USEC. Balances can be positive or negative at the discretion of the fabricator. Fabricators have other inventory supplies and, where a fabricator has elected to order less material from USEC than USEC is required to deliver to its customers at the fabricator, the fabricator will use these other inventories to satisfy USEC’s customer order obligations on USEC’s behalf. In such cases, the transfer of title of LEU from USEC to the customer results in quantities of SWU and uranium owed by USEC to the fabricator. These obligations are presented in current liabilities, comprising most of the balance of inventories owed to customers and suppliers. The amounts of SWU and uranium owed to fabricators are satisfied as future bulk deliveries of LEU are made. Inventories of SWU and uranium are valued at the lower of cost or market. Market is based on the terms of long-term contracts with customers, and, for uranium not under contract, market is based primarily on published price indicators at the balance sheet date. SWU and uranium inventory costs are determined using the monthly moving average cost method. SWU costs are based on Russian SWU purchase costs and past production costs. The cost of the SWU component of LEU purchased from Russia is recorded at acquisition cost plus related shipping costs. Past production costs at the Paducah GDP consisted principally of electric power, labor and benefits, materials, depreciation and amortization and maintenance and repairs. Past production also had included a mode of operation, called underfeeding, that used or fed less uranium but required more SWU in the enrichment process requiring more electric power. The quantity of uranium that was earned or added to uranium inventory from underfeeding was accounted for as a byproduct of the enrichment process. Production costs were allocated to the uranium earned based on the net realizable value of the uranium, and the remainder of production costs were allocated to SWU inventory costs. Inventories owed to customers and suppliers, included in current liabilities, consist primarily of SWU and uranium inventories owed to fabricators. Fabricators process LEU into fuel for use in nuclear reactors. Under inventory optimization arrangements between USEC and domestic fabricators, fabricators order bulk quantities of LEU from USEC based on scheduled or anticipated orders from utility customers for deliveries in future periods. As delivery obligations under actual customer orders arise, USEC satisfies these obligations by arranging for the transfer to the customer of title to the specified quantity of LEU at the fabricator. USEC’s balances of SWU and uranium vary over time based on the timing and size of the fabricator’s LEU orders from USEC and the fabricator's needs for working stock of LEU. Balances can be positive or negative at the discretion of the fabricator. Fabricators have other inventory supplies and, where a fabricator has elected to order less material from USEC than USEC is required to deliver to its customers at the fabricator, the fabricator will use these other inventories to satisfy USEC’s customer order obligations on USEC’s behalf. In such cases, the transfer of title of LEU from USEC to the customer results in quantities of SWU and uranium owed by USEC to the fabricator. The amounts of SWU and uranium owed to fabricators are satisfied as future bulk deliveries of LEU are made.
Income Tax, Policy [Policy Text Block]	Deferred Income Taxes USEC follows the asset and liability approach to account for deferred income taxes. Deferred tax assets and liabilities are recognized for the anticipated future tax consequences of temporary differences between the balance sheet carrying amounts of assets and liabilities and their respective tax bases. Deferred income taxes are based on income tax rates in effect for the years in which temporary differences are expected to reverse. The effect on deferred income taxes of a change in income tax rates is recognized in income when the change in rates is enacted in the law. A valuation allowance is provided if it is more likely than not that some or all of the deferred tax assets may not be realized.
Property, Plant and Equipment, Policy [Policy Text Block]	Property, Plant and Equipment Historically, USEC has recoded construction work in progress at acquisition or construction cost. Upon being placed into service, costs were transferred to leasehold improvements or machinery and equipment at which time depreciation and amortization commenced. Maintenance and repair costs are charged to production costs or cost of sales as incurred. USEC leases the Paducah GDP located in Paducah, Kentucky and portions of the former Portsmouth GDP located in Piketon, Ohio from DOE. Leasehold improvements and machinery and equipment are recorded at acquisition cost and depreciated on a straight line basis over the shorter of the useful life of the assets or the expected productive life of the plant. Beginning in the fourth quarter of 2012, the expected productive life of property, plant and equipment at the Paducah GDP was reduced from the lease term ending June 2016 to an accelerated basis ending December 2014. In addition, beginning in the third quarter of 2012, costs that would have been previously treated as construction work in progress are treated similar to maintenance and repair costs because of the shorter expected productive life of the Paducah GDP. The expected productive life of the Paducah GDP was further reduced following the ceasing of enrichment at the end of May 2013. In general, these assets, depending on their continuing economic life, are now expected to be useful only through the first half of 2014. Beginning with the start of the fourth quarter of 2011, all American Centrifuge project costs incurred have been expensed. Based on USEC’s internal analysis concluded as part of its annual assessment, all previously capitalized costs related to the American Centrifuge project were expensed as of December 31, 2012. Capitalization of expenditures related to the American Centrifuge project has ceased until commercial deployment resumes. Additional details related are provided below in “Advanced Technology Costs.”
Advanced Technology Costs, Policy [Policy Text Block]	Advanced Technology Costs Historically, costs relating to the American Centrifuge technology were either charged to expense or capitalized based on the nature of the activities and estimates and judgments involving the completion of project milestones. Costs relating to the demonstration of American Centrifuge technology were charged to expense as incurred and costs relating to the construction and deployment of the ACP were capitalized. Instead of moving forward with a conditional commitment for a loan guarantee for the American Centrifuge project through the DOE Loan Guarantee Program, in the fall of 2011, DOE proposed a two-year cost share RD&D Program for the American Centrifuge project. As a result of the shift in focus of the American Centrifuge project, beginning in the fourth quarter of 2011, USEC began spending on the American Centrifuge technology at reduced levels with activities concentrating on development and demonstration. As a result, beginning with the fourth quarter of 2011, all project costs incurred have been expensed, including interest expense that previously would have been capitalized. Refer to Note 8, "Property, Plant and Equipment" and Note 20, "Commitments and Contingencies" for further details.
Long-Lived Assets, Policy [Policy Text Block]	Long-Lived Assets USEC evaluates the carrying value of long-lived assets by performing impairment tests on an annual basis or whenever adverse conditions or changes in circumstances indicate a possible impairment loss. Impairment tests are based on a comparison of estimated undiscounted future cash flows to the carrying values of long-lived assets. If impairment is indicated, the asset carrying value is reduced to fair market value or, if fair market value is not readily available, the asset is reduced to a value determined by applying a discount rate to expected cash flows. Based on USEC’s internal analysis concluded as part of its annual assessment, all previously capitalized costs related to the American Centrifuge project were expensed as of December 31, 2012. Although USEC continues to make progress in the deployment of the ACP, including the effective execution of the RD&D Program during 2012 and 2013, the expense of previously capitalized costs was based on USEC’s assessment of its ability to recover the full amount of this prior capital investment. In light of the significant remaining capital needed to deploy the ACP and USEC’s view of its anticipated cash flow from operations available to finance the ACP given USEC’s other anticipated cash needs during that period, USEC anticipates that its ultimate share of the ownership of the ACP will likely be reduced, which affects its likelihood of recovering this past investment. This expense of previously capitalized costs does not affect any future capital investment in the ACP. USEC would anticipate that capitalization of amounts related to the ACP would resume if and when commercial plant deployment resumes.
Fair Value of Financial Instruments, Policy [Policy Text Block]	Financial Instruments and Fair Value Measurement Accounting standards define fair value as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required or permitted to be recorded at fair value, consideration is given to the principal or most advantageous market and assumptions that market participants would use when pricing the asset or liability. Pursuant to accounting standards, USEC’s convertible debt are recorded at face value and the fair value is disclosed. The estimated fair value of the convertible notes is based on the trading price as of the balance sheet date. Financing costs are generally deferred and amortized over the life of the instrument. Pursuant to accounting standards, USEC’s convertible preferred stock was initially recorded at fair value on a recurring basis. The preferred stock is classified as a liability since it is convertible for a variable number of shares of common stock based on a fixed monetary value known at the issuance date. Since the preferred stock is classified as a liability, the proceeds were first allocated to the liability instrument's full fair value, and no residual proceeds remained to be assigned to the warrants. Upfront costs and fees related to the investment were expensed in 2010 and classified as preferred stock issuance costs. The issuance costs were expensed in the period of issuance, rather than deferred and amortized, since the preferred stock is classified as a liability and was initially recorded at fair value. Dividends paid-in-kind, either issued or payable, are classified as interest. As of December 31, 2013, the convertible preferred stock can be converted at the holder’s option and is classified as a current liability at the redemption value. If a share issuance limitation were to exist at the time of share conversion or sale, any preferred stock shares subject to the share issuance limitation would be subject to optional or mandatory redemption for, at USEC's option, cash or SWU consideration. However, USEC’s ability to redeem may be limited by Delaware law. The balance sheet carrying amounts for cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities, and payables under the Russian Contract approximate fair value because of the short-term nature of the instruments.
Asset Retirement Obligations, Policy [Policy Text Block]	Lease Turnover Costs and Asset Retirement Obligations Property, plant and equipment assets related to the Paducah GDP are not subject to an asset retirement obligation. At the end of the GDP lease, ownership of plant and equipment that USEC leaves at the GDP transfers to DOE, and responsibility for decontamination and decommissioning ("D&D") of the GDP remains with DOE. USEC estimates and accrues lease turnover costs. Costs of returning the GDP to DOE in acceptable condition include removing nuclear material as required and removing USEC-generated waste. Liabilities for lease turnover costs are based on current-dollar cost estimates and are not discounted. USEC also leases facilities in Piketon, Ohio from DOE for the ACP. Pursuant to contract, DOE has obtained title to certain equipment used in the RD&D Program. Other than equipment transferred to DOE (collectively “DOE Transferred Property”), USEC owns all capital improvements and, unless otherwise consented to by DOE, must remove them by the conclusion of the lease term. At the conclusion of the lease, USEC is obligated to return these leased facilities to DOE in a condition that meets U.S. Nuclear Regulatory Commission ("NRC") requirements and in the same condition as the facilities were in when they were leased to USEC (other than due to normal wear and tear). In the event USEC returns the facilities in Piketon, Ohio prior to completing installation of 1 million SWU of capacity, DOE retains title to and responsibility for disposition of the DOE Transferred Property. D&D requirements for the ACP create an asset retirement obligation. As construction of the ACP takes place, the present value of the related asset retirement obligation (the initially determined fair value of the future obligation) is recognized as a long-term liability. An equivalent amount was and would be recognized as part of the capitalized asset cost during the previous construction period and when commercial plant deployment resumes. Upon commencement of commercial operations, the asset cost will be depreciated over the shorter of the asset life or the expected lease period. The capitalization of asset retirement obligations based on construction progress has been suspended since the third quarter of 2009, when USEC significantly reduced machine manufacturing and construction activities due to project funding uncertainty. In 2012, USEC expensed previously capitalized costs related to the American Centrifuge project and there is no ARO asset balance as of December 31, 2013. The long-term liability for the asset retirement obligation is accreted, or increased, for the passage of time and the estimate also is revised for any changes in long-term inflation rate assumptions. The accretion, based on a time value of money calculation, is charged to cost of sales in the LEU segment. At the end of 2010, USEC reassessed the long-term liability and determined that the current fair value of the obligation was accrued at a sufficient amount based on construction progress and no further increase would be made until additional commercial plant deployment resumes. When ACP commercial plant deployment resumes, USEC will begin again to reassess and revise the estimate of the asset retirement obligation during each reporting period based on construction progress, cost evaluation of future decommissioning expectations, and other judgmental considerations which impact the amount recorded in both construction work in progress and other long-term liabilities. Significant increases in asset retirement obligations and related capitalized asset costs would result when ACP construction is fully underway as part of any commercial plant deployment and plant operations.
Environmental Costs, Policy [Policy Text Block]	Environmental Compliance Costs Estimated environmental compliance costs are accrued where environmental assessments indicate that storage, treatment or disposal of wastes is probable and costs can be reasonably estimated. Liabilities for the storage, treatment or disposal of waste are based on current-dollar cost estimates and are not discounted.
Revenue Recognition, Policy [Policy Text Block]	SWU and Uranium Revenue Revenue is derived from sales of the SWU component of LEU, from sales of both the SWU and uranium components of LEU, and from sales of uranium. Revenue is recognized at the time LEU or uranium is delivered under the terms of contracts with domestic and international electric utility customers. Some customers take title and delivery of LEU at the Paducah GDP, and revenue is recognized when delivery of LEU to the customer is complete. Most customers take title and delivery of LEU at fuel fabricators. USEC ships LEU to nuclear fuel fabricators for scheduled or anticipated orders from utility customers. Based on customer orders, USEC arranges for the transfer of title of LEU from USEC to the customer for the specified quantity of LEU at the fuel fabricator. Revenue is recognized when delivery of LEU to the customer occurs at the fuel fabricator. In a number of sales transactions, title to uranium or LEU is transferred to the customer and USEC receives payment under normal credit terms without physically delivering the uranium or LEU to the customer. This may occur because the terms of the agreement require USEC to hold the uranium to which the customer has title, or because the customer encounters brief delays in taking delivery of LEU at USEC’s facilities. In such cases, recognition of revenue does not occur at the time title to uranium or LEU transfers to the customer but instead is deferred until LEU to which the customer has title is physically delivered. Certain customers make advance payments to be applied against future orders. Advances from customers are reported as deferred revenue, and revenue is recognized as product is delivered or services are provided. Contract Services Revenue USEC performs services and earns revenue from contract work from limited contract work for DOE and DOE contractors at the Paducah GDP and the Portsmouth site. Contract services revenue includes billings for fees and reimbursements for allowable costs that are determined in accordance with the terms of the underlying contracts. Revenue is recognized as work is performed and as fees are earned. Allowable costs include direct costs as well as allocations of indirect plant and corporate overhead costs determined in accordance with government cost accounting standards. Amounts representing contract change orders or final billing rates based on incurred costs are accrued and included in revenue when they can be reliably estimated and realization is probable. Allowable costs are subject to audit by the Defense Contract Audit Agency ("DCAA"), or such other entity that DOE authorizes to conduct the audit. The final settlement of amounts submitted by USEC for reimbursement is subject to Federal Acquisition Regulations requiring the DOE contracting officer to conduct negotiations and prepare a written indirect cost agreement. Revenue resulting from final billing rates is recognized upon completion of the government audits and notice by DOE authorizing final billing. DOE historically has not approved USEC’s provisional billing rates and has not completed audits of USEC’s incurred cost submissions and authorized final payments in a timely manner. Additional details are provided in Note 6. There is the potential for additional revenue to be recognized, based on the outcome of DOE reviews and audits, as the result of the release of previously established receivable related reserves. However, because these periods have not been finalized with DOE, uncertainty exists and USEC has not yet recognized this additional revenue.
Share-based Compensation, Policy [Policy Text Block]	Stock-Based Compensation USEC historically has had stock-based compensation plans available to grant restricted stock, restricted stock units, non-qualified stock options, performance awards and other stock-based awards to key employees and non-employee directors. Stock-based compensation cost is measured at the grant date, based on the fair value of the award, and is recognized over the requisite service period, which is either immediate recognition if the employee is eligible to retire, or on a straight-line basis until the earlier of either the date of retirement eligibility or the end of the vesting period.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect reported amounts presented and disclosed in the consolidated financial statements. Significant estimates and judgments include, but are not limited to, asset valuations, asset retirement obligations and transition costs, pension and postretirement health and life benefit costs and obligations, the tax bases of assets and liabilities, the future recoverability of deferred tax assets, and determination of the valuation allowance for deferred tax assets. Actual results may differ from such estimates, and estimates may change if the underlying conditions or assumptions change.