Centrus Energy (LEU) 10-Q 5 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Oct. 31, 2013
Document and Entity Information	'	'
Entity Registrant Name	'USEC INC	'
Entity Central Index Key	'0001065059	'
Current Fiscal Year End Date	'--12-31	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-13	'
Entity Filer Category	'Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	4,948,235
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'

CONSOLIDATED_CONDENSED_BALANCE

CONSOLIDATED CONDENSED BALANCE SHEETS (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Current Assets	'	'
Cash and cash equivalents	$128.40	$292.90
Accounts receivable, net	158.7	134.8
Inventories	1,176.80	1,593.20
Deferred costs associated with deferred revenue	136.6	116.8
Other current assets	22.6	19.2
Total Current Assets	1,623.10	2,156.90
Property, Plant and Equipment, net	13	51
Other Long-Term Assets	'	'
Deposits for surety bonds	39.8	22.3
Goodwill	0	6.8
Other assets	27.9	29.4
Total Other Long-Term Assets	67.7	58.5
Total Assets	1,703.80	2,266.40
Current Liabilities	'	'
Accounts payable and accrued liabilities	121.3	145.8
Payables under Russian Contract	324.8	209.8
Inventories owed to customers and suppliers	475.9	950
Deferred revenue and advances from customers	163.7	125.5
Credit facility term loan	0	83.2
Convertible preferred stock	110.4	100.5
Total Current Liabilities	1,196.10	1,614.80
Long-Term Debt	530	530
Other Long-Term Liabilities	'	'
Postretirement health and life benefit obligations	215.3	207.2
Pension benefit liabilities	171.2	321.7
Other liabilities	53.3	65.6
Total Other Long-Term Liabilities	439.8	594.5
Commitments and Contingencies (Note 15)	'	'
Stockholders’ Equity (Deficit)	-462.1	-472.9
Total Liabilities and Stockholders’ Equity (Deficit)	$1,703.80	$2,266.40

CONSOLIDATED_CONDENSED_STATEME

CONSOLIDATED CONDENSED STATEMENTS OF OPERATIONS (USD $)	3 Months Ended		9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenue:	'	'	'	'
Separative work units	$295.80	$559.50	$853.40	$1,444.60
Uranium	3.8	0	45.3	3.6
Contract services	4.2	3.5	10.3	10.6
Total Revenue	303.8	563	909	1,458.80
Cost of Sales:	'	'	'	'
Separative work units and uranium	330.4	522.8	962.4	1,364.40
Contract services	3.4	3.6	10.2	10.9
Total Cost of Sales	333.8	526.4	972.6	1,375.30
Gross profit (loss)	-30	36.6	-63.6	83.5
Advanced technology costs	44.5	44.9	150	167
Selling, general and administrative	11.2	11.3	36	38.1
Special charges for workforce reductions and advisory costs	3.5	1.5	9.6	11.1
Other (income)	-35.9	-34.6	-124.2	-44.6
Operating income (loss)	-53.3	13.5	-135	-88.1
Interest expense	9.5	12.3	32.1	37.7
Interest (income)	0	-0.2	-0.4	-0.4
Income (loss) from continuing operations before income taxes	-62.8	1.4	-166.7	-125.4
Provision (benefit) for income taxes	-18.5	-3.6	-57.8	-9
Net income (loss) from continuing operations	-44.3	5	-108.9	-116.4
Net income (loss) from discontinued operations	0	-0.5	21.7	0.1
Net income (loss)	($44.30)	$4.50	($87.20)	($116.30)
Net income (loss) from continuing operations per share – basic and diluted	($9.04)	$1.02	($22.22)	($23.75)
Net income (loss) per share – basic and diluted	($9.04)	$0.92	($17.79)	($23.73)
Weighted-average number of shares outstanding:	'	'	'	'
Weighted-average number of shares outstanding – basic and diluted	4.9	4.9	4.9	4.9

CONSOLIDATED_CONDENSED_STATEME1

CONSOLIDATED CONDENSED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]	'	'	'	'
Net income (loss)	($44.30)	$4.50	($87.20)	($116.30)
Gain arising during the period (Note 11)	0	0	138.3	0
Amortization of actuarial (gains) losses, net (Note 11)	2.6	6.2	15.5	18.2
Amortization of prior service costs (Note 11)	0	-0.3	-0.7	-1.1
Other comprehensive income, before tax	2.6	6.5	154.5	19.3
Income tax expense related to items of other comprehensive income	-1.5	-2.4	-58	-7
Other comprehensive income, net of tax	1.1	4.1	96.5	12.3
Comprehensive income (loss)	($43.20)	$8.60	$9.30	($104)

CONSOLIDATED_CONDENSED_STATEME2

CONSOLIDATED CONDENSED STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Cash Flows from Operating Activities	'	'
Net income (loss)	($87.20)	($116.30)
Adjustments to reconcile net (loss) to net cash provided by (used in) operating activities:	'	'
Depreciation and amortization	22.8	27.5
Transfers and retirements of machinery and equipment	19.3	47.4
Deferred income taxes	0	-7
Other non-cash income on release of disposal obligation	0	-44.6
Convertible preferred stock dividends payable-in-kind	9.9	8.8
Gain on sale of subsidiary	-35.6	0
Inventory valuation adjustments	15	0
Changes in operating assets and liabilities:	'	'
Accounts receivable – (increase)	-23.9	-9.9
Inventories, net – (increase) decrease	-72.7	271.1
Payables under Russian Contract – increase	115	39.4
Deferred revenue, net of deferred costs – increase	17.6	91.4
Accounts payable and other liabilities – increase (decrease)	-80.4	15.3
Accrued depleted uranium disposition – increase (decrease)	0.3	-145
Other, net	-4.7	2.4
Net Cash Provided by (Used in) Operating Activities	-104.6	180.5
Cash Flows Provided by Investing Activities	'	'
Capital expenditures	0	-3.8
Deposits for surety bonds - net (increase) decrease	-17.5	99.6
Proceeds from sale of subsidiary	43.2	0
Net Cash Provided by Investing Activities	25.7	95.8
Cash Flows Used in Financing Activities	'	'
Borrowings under revolving credit facility	0	123.6
Repayments under revolving credit facility	0	-123.6
Repayment of credit facility term loan	-83.2	0
Payments for deferred financing costs	-2.2	-10.1
Common stock issued (purchased), net	-0.2	-0.5
Net Cash (Used in) Financing Activities	-85.6	-10.6
Net Increase (Decrease)	-164.5	265.7
Cash and Cash Equivalents at Beginning of Period	292.9	37.6
Cash and Cash Equivalents at End of Period	128.4	303.3
Supplemental Cash Flow Information:	'	'
Interest paid	20.7	16.5
Income taxes paid, net of refunds	$0.40	$1.30

CONSOLIDATED_CONDENSED_STATEME3

CONSOLIDATED CONDENSED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $)	Total	Common Stock Par Value $.10 per Share [Member]	Excess of Capital over Par Value [Member]	Retained Earnings (Deficit) [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income [Member]
In Millions
Beginning Balance at Dec. 31, 2011	$752.40	$13	$1,212.50	($161.20)	($49.40)	($262.50)
Other comprehensive income, net of tax (Note 16)	12.3	'	'	'	'	12.3
Restricted and other common stock issued, net of amortization	3.8	'	-12.6	'	16.4	'
Reverse stock split of 1 share for 25 (Note 1)	'	-12.5	12.5	'	'	'
Net income (loss)	-116.3	'	'	-116.3	'	'
Ending Balance at Sep. 30, 2012	652.2	0.5	1,212.40	-277.5	-33	-250.2
Beginning Balance at Dec. 31, 2012	-472.9	13	1,200.80	-1,361.80	-33	-291.9
Other comprehensive income, net of tax (Note 16)	96.5	'	'	'	'	96.5
Restricted and other common stock issued, net of amortization	1.5	'	2.9	'	-1.4	'
Reverse stock split of 1 share for 25 (Note 1)	12.5	-12.5	12.5	'	'	'
Net income (loss)	-87.2	'	'	-87.2	'	'
Ending Balance at Sep. 30, 2013	($462.10)	$0.50	$1,216.20	($1,449)	($34.40)	($195.40)

Basis_of_Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Basis of Presentation	'
	BASIS OF PRESENTATION
	The unaudited consolidated condensed financial statements as of and for the three and nine months ended September 30, 2013 and 2012 have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. The unaudited consolidated condensed financial statements reflect all adjustments which are, in the opinion of management, necessary for a fair statement of the financial results for the interim period. Certain information and notes normally included in financial statements prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) have been omitted pursuant to such rules and regulations. Certain amounts in the consolidated condensed financial statements have been reclassified to conform to the current presentation.
	Operating results for the three and nine months ended September 30, 2013 are not necessarily indicative of the results that may be expected for the year ending December 31, 2013. The unaudited consolidated condensed financial statements should be read in conjunction with the consolidated financial statements and related notes and management's discussion and analysis of financial condition and results of operations included in the annual report on Form 10-K for the year ended December 31, 2012.
	Reverse Stock Split
	On July 1, 2013, USEC effectuated a reverse stock split of 1-for-25 shares as described below, resulting in a reclassification from Common Stock to Excess of Capital over Par Value of $12.5 million.
	Liquidity Risks and Uncertainties
	USEC's consolidated condensed financial statements have been prepared assuming that USEC will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business for the 12-month period following the date of these financial statements.
	USEC reported a net loss of $1.2 billion in the year ended December 31, 2012 and a net loss of $491.1 million in the year ended December 31, 2011.  These net losses were primarily the result of expenses related to the development of the American Centrifuge project, including the expense of previously capitalized amounts during both periods and related tax valuation allowances.  USEC reported a net loss of $87.2 million for the nine months ended September 30, 2013 and cash and cash equivalents of $128.4 million as of September 30, 2013. Although USEC expects to end 2013 with a cash balance exceeding $250 million, USEC's prospects for adequate liquidity in 2014 are uncertain. USEC's liquidity is dependent on a number of factors, including (i) USEC's operating needs; (ii) the level of expenditures for the American Centrifuge project, including the availability of any additional government funding of the American Centrifuge project after the conclusion of the research, development and demonstration ("RD&D") program, which is scheduled to be completed by December 31, 2013, and the potential demobilization or termination costs if post-RD&D funding is not available or if USEC determines there is no longer a viable path to commercialization of the American Centrifuge Plant project; (iii) the amount and timing of transition expenses for the Paducah gaseous diffusion plant ("GDP") and USEC’s ability to reach an acceptable agreement with DOE for the transition; and (iv) USEC’s ability to restructure its $530.0 million of convertible senior notes that mature on October 1, 2014, all of which impact USEC’s liquidity.
	Consistent with prior years, USEC's payments to Russia for separative work units ("SWU") in the first quarter of 2014 are expected to exceed USEC's cash receipts from customers in that quarter, putting pressure on its liquidity in mid-2014 until deliveries to customers under its backlog occur later in the year. USEC's $110.0 million credit facility matured on September 30, 2013 and was not renewed or replaced. USEC’s working capital requirements are substantially reduced as a result of the conclusion of USEC's contract with Russia (the "Russian Contract") under the 20-year Megatons-to-Megawatts program that ends in 2013 and the cessation of enrichment at the Paducah GDP as of May 31, 2013. Purchase quantities under the new 10-year commercial agreement with Russia (the "Russian Supply Agreement") will be about half the level under the Russian Contract unless the parties exercise a mutual option to increase such purchases. USEC intends to work with customers to modify delivery schedules to provide sufficient liquidity and working capital for USEC’s operating needs. However, the timing of customer deliveries, including Japanese customers who are affected by the prolonged outage of Japanese reactors, could create risks to USEC’s liquidity. USEC’s ability to manage unanticipated expenses or delays in customer orders or payments is reduced without a credit facility, which could adversely affect USEC’s liquidity.
	USEC will need to restructure its convertible senior notes of $530.0 million before the maturity date of October 1, 2014. In light of the significant transition of USEC's business and the uncertainties and challenges facing USEC and in order to address the convertible notes maturity and improve USEC's credit profile and its ability to successfully finance and deploy the American Centrifuge project and to maximize USEC's participation in such project, USEC is engaged with its advisors and certain stakeholders on alternatives for a possible restructuring of its balance sheet. Although USEC has no assurance regarding its ability to pursue or complete a restructuring, a restructuring would be expected to result in significant changes to the Company's capital structure and adjustments to its balance sheet, including the creation of a new entity for accounting purposes, which would have a material impact on USEC's financial statements, including the going concern assumption on which they have been prepared.
	The economics of the American Centrifuge project are severely challenged by the current supply/demand imbalance in the market for low enriched uranium ("LEU") and related downward pressure on market prices for SWU which are now at their lowest levels in more than a decade. At current market prices USEC does not believe that its plans for American Centrifuge commercialization are economically viable without additional government support. In addition, USEC does not currently have any financing in place for the project following completion of the RD&D program in December 2013 and anticipates that funding will be needed for the project for the period from completion of the RD&D program until the receipt of financing for commercial deployment. The amount of any such funding would depend on the level of operations, manufacturing and other project infrastructure that is to be maintained in order to support a potential future ramp up to commercialization as well as the length of time until financing could be obtained for the plant. USEC is evaluating and pursuing the feasibility of alternatives and the actions necessary to proceed with the commercial deployment of the American Centrifuge technology, including the availability of additional government support and has initiated discussions with DOE regarding the project’s need for this support. However, USEC has no assurance that it will be successful in achieving any of these measures or the timing thereof. In light of USEC’s liquidity, USEC does not have the ability to continue to fund the American Centrifuge project at its current levels beyond the end of 2013 without additional government support and even with this support USEC’s ability to provide funding in 2014 will be limited. Therefore, USEC continues to evaluate its options concerning the American Centrifuge project, including its ability to continue the project prior to or upon completion of the RD&D program, further demobilization of or delays in the commercial deployment of the project, and termination of the project, and could make a decision to demobilize or terminate the project in the near term. Any such actions may have a material adverse impact on USEC's ability to deploy the American Centrifuge technology, on its liquidity and on the long-term viability of its enrichment business.  See Note 15, “American Centrifuge Plant” for additional information.
	In addition, on May 8, 2012, USEC received a notice from the New York Stock Exchange ("NYSE") that the average closing price of its common stock was below the NYSE's continued listing criteria relating to minimum share price. On July 1, 2013, USEC effectuated a reverse stock split of 1-for-25 shares in order to regain compliance with the NYSE continued listing criteria related to minimum share price. This action resulted in USEC's closing share price exceeding $1.00 per share and remaining above that level, and the condition has now been cured. However, on April 30, 2013, USEC received notice from the NYSE that the decline in USEC's total market capitalization had caused it to be out of compliance with another of the NYSE's continued listing standards. In accordance with the NYSE's rules, USEC submitted a plan advising the NYSE of definitive action it has taken, or is taking, that would bring it into conformity with the market capitalization listing standards within 18 months of receipt of the letter. On August 1, 2013, the NYSE accepted USEC's plan of compliance and USEC's common stock will continue to be listed on the NYSE during the 18-month cure period, subject to the compliance with other NYSE continued listing standards and continued periodic review by the NYSE of USEC's progress with respect to its plan. USEC's plan outlines initiatives USEC must execute by quarter. These initiatives include the successful completion of development milestones for the American Centrifuge Plant, the commercialization of the American Centrifuge project, as well as the successful execution of the Company's Russian Supply Agreement and the Company's potential balance sheet restructuring.  The NYSE has notified us that if USEC does not achieve these financial and operational goals, the Company will be subject to NYSE trading suspension at the point the initiative or goal is not met.
	Under the terms of USEC's convertible notes, a "fundamental change" is triggered if USEC's shares of common stock are not listed for trading on any of the NYSE, the American Stock Exchange (now NYSE-MKT), the NASDAQ Global Market or the NASDAQ Global Select Market, and the holders of the notes can require USEC to repurchase the notes at par for cash. USEC has no assurance that it would be eligible for listing on an alternate exchange in light of its market capitalization, stockholders' deficit and net losses. In the event a fundamental change under the convertible notes is triggered, USEC does not have adequate cash to repurchase the notes.  A failure by USEC to offer to repurchase the notes or to repurchase the notes after the occurrence of a fundamental change is an event of default under the indenture governing the notes. See Note 15, “NYSE Listing Standards Notices” for additional information.
	USEC is in discussions with the Pension Benefit Guaranty Corporation ("PBGC") regarding the impact of its de-lease of the Portsmouth GDP and related transition of employees on its defined benefit plan funding obligations as well as the impact of ceasing enrichment at the Paducah GDP and related transition of employees including reductions in force.  See Note 15, “Potential ERISA Section 4062(e) Liability” for additional information.
	The above noted actions, as well as actions that may be taken by vendors, customers, creditors and other third parties in response to its actions or based on their view of its financial strength and future business prospects, could give rise to events that individually, or in the aggregate, impose significant demands on USEC's liquidity.
	New Accounting Standards
	In February 2013, the Financial Accounting Standards Board ("FASB") issued guidance on the presentation of accumulated other comprehensive income ("AOCI"), adding new disclosure requirements for items reclassified out of AOCI. The new guidance does not amend any existing requirements for reporting net income or other comprehensive income in the financial statements. The implementation of the new pronouncement in 2013 is reflected in the notes to USEC’s consolidated condensed financial statements and did not have an effect on USEC’s results of operations, cash flows or financial position.
	In July 2013, the FASB issued guidance requiring an entity to present unrecognized tax benefits as a reduction to deferred tax assets when a net operating loss carryforward, similar tax loss or a tax credit carryforward exists, with limited exceptions. This pronouncement is effective beginning in the first quarter of 2014. USEC has historically presented uncertain tax positions in accordance with the new guidance and does not expect it to have a material impact on its consolidated financial statements.

Sale_of_NAC_Subsidiary

Sale of NAC Subsidiary	9 Months Ended
	Sep. 30, 2013
Discontinued Operation, Additional Disclosures [Abstract]	'
Sale of NAC Subsidiary	'
	SALE OF NAC SUBSIDIARY
	On January 23, 2013, USEC entered into a stock purchase agreement (the “Stock Purchase Agreement”) with Hitz Holdings U.S.A. Inc. (“Hitz”), a subsidiary of Hitachi Zosen Corporation. Pursuant to the Stock Purchase Agreement, on March 15, 2013, Hitz acquired all of the outstanding shares of USEC’s wholly-owned subsidiary NAC International, Inc. (“NAC”).  NAC was acquired by USEC in 2004 and provides transportation and storage systems for spent nuclear fuel and provides nuclear and energy consulting services. USEC recorded a gain on the sale of $35.6 million in the first quarter of 2013, representing the final sale proceeds of $43.2 million less the net carrying amount of NAC assets and liabilities of $5.5 million (including goodwill of $6.8 million) and transaction costs of $2.1 million.
	The following financial information related to NAC is segregated from continuing operations and reported as discontinued operations (in millions). Results for 2013 reported in discontinued operations are through the date of divestiture of March 15, 2013.
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
		2013		2012			2013		2012
	Revenue	$	—	$	7.5		$	13.7	$	38
	Cost of sales	—		6.6			11.8		32.9
	Gross profit	—		0.9			1.9		5.1
	Advanced technology costs	—		0.2			—		0.6
	Selling, general and administrative	—		1.5			1.8		4.4
	Operating income (loss)	—		(0.8		)	0.1		0.1
	Gain on sale of subsidiary	—		—			35.6		—
	Income (loss) before income taxes	—		(0.8		)	35.7		0.1
	Provision (benefit) for income taxes	—		(0.3		)	14		—
	Net income (loss) from discontinued operations	$	—	$	(0.5	)	$	21.7	$	0.1

Transition_Charges

Transition Charges	9 Months Ended
	Sep. 30, 2013
Restructuring and Related Activities [Abstract]	'
Transition Charges	'
	3. TRANSITION CHARGES
	Non-Production Expenses Related to Ceasing Enrichment at the Paducah Plant
	On May 24, 2013, USEC announced that it was not able to conclude a deal for the short-term extension of uranium enrichment at the Paducah GDP. USEC ceased uranium enrichment at the end of May 2013 and completed withdrawing material from the cascade in early June. USEC is in discussions with the U.S. Department of Energy ("DOE") regarding the timing of USEC’s de-lease of the Paducah GDP from DOE and is seeking to minimize its transition costs related to lease turnover, which could be substantial.
	Under the terms of the lease, USEC can terminate the lease prior to June 2016 upon two years' notice. Also, as USEC's requirements change, USEC can de-lease portions of the property under lease upon 60 days' notice with DOE's consent, which cannot be unreasonably withheld. However, the right of partial de-lease does not include the right of USEC to terminate the lease in its entirety or with respect to the Paducah GDP, which termination is permitted only in accordance with the two-year termination provision of the lease. On August 1, 2013, USEC provided notice to DOE that USEC exercised its rights to terminate the lease with respect to the Paducah GDP and USEC has been in discussions with DOE regarding the timing of USEC’s de-lease. USEC anticipates being able to complete the return of leased premises and terminate the Paducah GDP lease as early as July 2014, but DOE and USEC have not reached agreement on a lease termination date prior to August 1, 2015. DOE has indicated that its ability to agree to such an earlier date will depend on the availability of funding among other things. In the event that USEC is unable to agree with DOE on a schedule for termination prior to two years, USEC plans to retain a small portion of the leased premises until August 1, 2015, at which time the Paducah GDP lease will terminate and any remaining portion of the leased premises will be returned to DOE. In such an event, during this period USEC plans to return portions of the leased premises no longer required to meet its business needs. However, limitations on available funding to DOE in light of federal budget constraints and spending cuts could limit DOE's willingness to accept the return of areas that USEC wishes to de-lease on a timely basis. In addition, while DOE has stated that it continues to be willing to work with USEC to develop a transition plan and schedule for the safe and secure return of the Paducah GDP, DOE has taken the position that USEC is foreclosed from invoking its rights to a partial return of facilities under the lease. USEC strongly disagrees with this DOE position. Disputes could also arise regarding the requirements of the lease and responsibility for associated turnover costs.
	The Paducah GDP operated for more than 60 years. Environmental liabilities associated with plant operations by agencies of the U.S. government prior to USEC's privatization on July 28, 1998 are the responsibility of the U.S. government. The USEC Privatization Act and the lease for the plant provide that DOE remains responsible for decontamination and decommissioning of the Paducah site.
	As USEC accelerated the expected productive life of plant assets and ceased uranium enrichment at the Paducah GDP, USEC has incurred a number of expenses unrelated to production that have been charged directly to cost of sales. Non-production expenses totaled $47.7 million and $123.4 million in the three and nine months ended September 30, 2013, and $6.1 million and $12.7 million in the three and nine months ended September 30, 2012, as follows:
	-	Site expenses, including lease turnover activities and Paducah and Portsmouth retiree benefit costs, of $37.4 million in the three months and $63.8 million in the nine months ended September 30, 2013. Following the cessation of enrichment at the Paducah GDP, costs for plant activities that formerly were capitalized as production costs are now charged directly to cost of sales including inventory management and disposition, ongoing regulatory compliance, utility requirements for operations, security, and other site management activities related to transition of facilities and infrastructure.
	Prior to the start of 2012, a significant portion of retiree benefit costs were attributed to Portsmouth contract services, based on the employee base performing contract services work. Starting in 2012, ongoing retiree benefit costs related to USEC's former Portsmouth employees are charged to cost of sales of the LEU segment rather than the contract services segment based on continuing operations that support USEC's active and retired employees. Non-production expenses of $3.3 million and $9.9 million in the three and nine months ended September 30, 2012, respectively, relate to Portsmouth retiree benefit costs;
	-	Accelerated asset charges of $5.3 million and $13.5 million in the three and nine months ended September 30, 2013, respectively, and $2.8 million in the three and nine months ended September 30, 2012. 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 or second quarters of 2014;
	-	Inventory valuation adjustments of $5.0 million in the three months and $15.0 million in the nine months ended September 30, 2013. Inventories of SWU and uranium are valued at lower of cost or market. In the three-month period, a uranium inventory valuation adjustment of $5.0 million was charged to cost of sales to reflect declines in uranium market price indicators. The nine-month period also included the expense of $7.7 million of residual uranium contained in certain cylinders that will be transferred to DOE. USEC determined that it was currently uneconomic to recover this residual uranium for resale. In addition, certain materials and supplies used in the enrichment process with a book value of $2.3 million were expensed following the termination of enrichment at the end of the second quarter 2013;
	-	Asset retirement charges of $19.3 million in the nine months ended September 30, 2013 for property, plant and equipment formerly used in the enrichment process at the Paducah GDP;
	-	Power contract losses of $11.8 million in the nine months ended September 30, 2013. In anticipation of a potential short-term extension of uranium enrichment at the Paducah GDP, USEC purchased approximately 700 megawatts of power for the period from June 1 through September 30, 2013 from several power providers. Due to falling prices in power markets following the purchase of this power, as part of agreements to unwind these purchases, USEC incurred expenses of approximately $11.8 million.
	USEC may incur additional non-production expense and special charges in future periods based on the results of the planning and execution of the Paducah transition and assessments of evolving business needs.
	Special Charges for Workforce Reductions and Advisory Costs
	On May 31, 2013, USEC notified its Paducah employees of potential layoffs beginning in August 2013. The notifications were provided under the Worker Adjustment and Retraining Notification Act ("WARN Act"), a federal statute that requires an employer to provide advance notice to its employees of potential layoffs in certain circumstances. Special charges for one-time termination benefits totaled $1.5 million and $3.6 million in the three and nine months ended September 30, 2013, respectively.
	Following the cessation of enrichment at the Paducah GDP in the second quarter of 2013, USEC initiated an initial workforce reduction of 140 employees that was substantially completed in August 2013. Associated year-to-date charges of $2.0 million for severance payments are net of $0.7 million of severance paid by USEC and invoiced to DOE. Total cash payments associated with this initial workforce reduction totaled $2.5 million as of September 30, 2013. Accounts receivable as of September 30, 2013 include $0.7 million for DOE's share of severance paid by USEC.
	On September 30, 2013, USEC's senior management authorized an additional workforce reduction of approximately 90 Paducah employees. This workforce reduction is expected to occur between October 2013 and January 2014. USEC currently estimates that it could incur employee related severance costs of approximately $1.6 million to $2.4 million for this expected workforce reduction depending on the seniority of the workers and final number of employees severed, with DOE owing a portion of this amount estimated to be up to $0.5 million. As such, USEC accrued a special charge associated with this workforce reduction of $1.6 million in the three months ended September 30, 2013 for estimated one-time termination benefits consisting of severance payments. Related cash expenditures are expected primarily in the fourth quarter of 2013 and first quarter of 2014.
	Additional layoffs are expected to occur in stages through 2014 depending on business needs to manage inventory, fulfill customer orders, meet regulatory requirements and transition the site back to DOE in a safe and orderly manner. Information on these additional layoffs would be communicated to affected employees in future notices and may result in additional charges. USEC currently estimates that it could incur total employee related severance costs of approximately $23 million to $27 million for all Paducah GDP workers in the event of a full termination of activities at the site without a transfer of employees to another employer, depending on the timing of severances, if incurred, and with DOE owing a portion of this amount estimated to be up to $6 million.
	Actions taken in the prior year resulted in special charges of $0.4 million and $4.0 million in the three and nine months ended September 30, 2012, respectively, for one-time termination benefits for affected employees at USEC's American Centrifuge design and engineering operations in Oak Ridge, Tennessee, the headquarters operations located in Bethesda, Maryland, and the central services operations located in Piketon, Ohio. Related cash expenditures were completed in 2012.
	In early 2012, USEC initiated an internal review of its organizational structure and engaged a management consulting firm to support this review. USEC is also engaged with its advisors and certain stakeholders on alternatives for a possible restructuring of its balance sheet. Special charges recorded for these advisors totaled $2.0 million and $6.7 million in the three months and nine months ended September 30, 2013, compared to $1.1 million and $7.1 million in the corresponding periods of 2012.
	As discussed in Note 11, "Pension and Postretirement Health and Life Benefits," USEC froze benefit accruals under its defined benefit pension plans, effective August 5, 2013, for active employees who are not covered by a collective bargaining agreement. Pension benefits will no longer increase for these employees to reflect changes in compensation or credited service. However, these employees will not lose any benefits earned through August 4, 2013 under the pension plans. Unamortized prior service costs related to those pension plan participants were accelerated and a plan re-measurement was conducted. The result was a curtailment gain of $0.7 million recorded in the second quarter of 2013 to special charges.

Advanced_Technology_Costs_and_

Advanced Technology Costs and Other Income	9 Months Ended
	Sep. 30, 2013
Research and Development [Abstract]	'
Advanced Technology Costs and Other Income	'
	ADVANCED TECHNOLOGY COSTS AND OTHER INCOME
	USEC is conducting a RD&D program for the American Centrifuge technology with cost share funding from DOE. The objectives of the RD&D program are to demonstrate the American Centrifuge technology through the construction and operation of a commercial demonstration cascade of 120 centrifuge machines and sustain the domestic U.S. centrifuge technical and industrial base for national security purposes and potential commercialization of the American Centrifuge technology. This includes activities to reduce the technical risks and improve the future prospects of deployment of the American Centrifuge technology. The June 2012 cooperative agreement with DOE, as most recently amended on October 25, 2013 ("the October 2013 Amendment"), defines the scope, funding and technical goals for the RD&D program. The cooperative agreement provides for 80% DOE and 20% USEC cost sharing for work performed during the period June 1, 2012 through December 31, 2013. The cooperative agreement is being incrementally funded, and $241.3 million of DOE funding has been provided as follows:
	•	$87.7 million of funding was provided by DOE accepting title to quantities of depleted uranium that enabled USEC to release encumbered funds that were providing financial assurance for the disposition of this depleted uranium;
	•	$45.7 million of funding was provided pursuant to the six-month continuing appropriations resolution passed by Congress and signed by the President on September 28, 2012;
	•	$44.4 million of funding was provided in March 2013 by DOE transferring the SWU component of LEU that DOE previously acquired from USEC in exchange for the transfer of quantities of USEC’s depleted uranium to DOE;
	•	$49.9 million of funding was provided pursuant to the FY2013 continuing appropriations resolution, through amendments to the cooperative agreement on June 13, 2013 and July 24, 2013; and
	•	$13.6 million of funding was provided pursuant to the FY2014 continuing appropriations resolution, through an amendment to the cooperative agreement on October 25, 2013.
	As of September 30, 2013, USEC has made cumulative qualifying American Centrifuge expenditures of $270.2 million. DOE’s pro-rata share is 80% or $216.2 million. Of the $216.2 million, $191.4 million has been received by USEC and DOE’s remaining funding share of $24.8 million is included in current accounts receivable as of September 30, 2013.
	In the nine months ended September 30, 2013 and 2012, USEC made qualifying American Centrifuge expenditures of $155.1 million and $55.7 million, respectively. DOE’s pro-rata share of 80%, or $124.1 million and $44.6 million, is recognized as other income in the nine months ended September 30, 2013 and 2012, respectively.
	The $13.6 million of additional government funding provided by the October 2013 Amendment is for the RD&D program funding period November 2, 2013 to December 31, 2013. Although this funding is not sufficient to fund the RD&D program through December 31, 2013, the October 2013 Amendment states that there is an expectation that DOE would provide additional funding for the RD&D program for the funding period ending December 31, 2013. The remaining funding would be made through a subsequent modification to the cooperative agreement, with the amount of such funding to be determined. USEC expects cumulative spending for the RD&D program for the period June 1, 2012 through December 31, 2013 to be approximately $320 million. This amount is less than the originally estimated cost of the program of up to $350 million as a result of cost savings achieved by the Company and spending reductions made by the Company to complete the program technical milestones within the reduced government funds anticipated to be available for the program.
	The government fiscal year 2014 continuing appropriations resolution passed by Congress and signed by the President on October 16, 2013 provided for continued funding for the U.S. government from October 1, 2013 through January 15, 2014. This resolution continued funding for the RD&D program at the government fiscal year 2013 annual rate of $110 million, less any automatic spending cuts applied to U.S. government spending. USEC believes that this level of funding, if provided, will be sufficient to fund the RD&D program through December 31, 2013 and achieve the remaining technical milestones within the reduced spending plan described above.
	There is no assurance that additional funding will be made available. DOE’s remaining cost share is conditioned upon USEC continuing to meet all milestones and deliverables on schedule, USEC continuing to demonstrate to DOE’s satisfaction its ability to meet future milestones, and the availability of such government funding.
	Additional details regarding funding for the American Centrifuge project and commitments and contingencies related to the American Centrifuge Plant under the 2002 DOE-USEC Agreement and the June 2012 cooperative agreement are provided in Note 15.

Accounts_Receivable

Accounts Receivable	9 Months Ended
	Sep. 30, 2013
Accounts Receivable, Net, Current [Abstract]	'
Accounts Receivable	'
	CURRENT AND LONG-TERM RECEIVABLES
		September 30,		December 31,
		2013		2012
		(millions)
	Utility customers	$	121.3	$	118.3
	DOE pro-rata share of RD&D program funding	24.8		4.4
	Contract services, primarily DOE:
	Billed revenue	9.7		10.5
	Unbilled revenue	2.9		1.6
		12.6		12.1
	Current accounts receivable, net	$	158.7	$	134.8
	Current accounts receivable are net of valuation allowances and allowances for doubtful accounts totaling $1.8 million at September 30, 2013 and $2.1 million at December 31, 2012.
	Additional details regarding DOE’s pro-rata share of funding for American Centrifuge expenditures under the RD&D program are provided in Note 4.
	Billings for contract services related to DOE are generally invoiced based on provisional billing rates approved by DOE. Unbilled revenue represents the difference between actual costs incurred, prior to incurred cost audit and notice by DOE authorizing final billing, and provisional billing rate invoiced amounts. Unbilled amounts are invoiced to DOE as billing rates are revised, submitted to and approved by DOE.
	Certain receivables from DOE are included in other long-term assets based on the extended timeframe expected to resolve claims for payment. As of December 31, 2012, long term receivables from DOE were $25.8 million, or $38.0 million net of valuation allowances of $12.2 million. USEC believes DOE has breached its agreements by failing to establish appropriate provisional billing and final indirect cost rates on a timely basis and USEC filed claims with DOE for payment under the Contract Disputes Act ("CDA"). On May 30, 2013, USEC appealed the DOE's denial of its claims to the U.S. Court of Federal Claims.
	On August 30, 2013, USEC submitted an additional claim to DOE under the CDA for payment of $42.8 million, representing DOE's share of pension and postretirement benefits costs related to the transition of Portsmouth site employees to DOE's decontamination and decommissioning ("D&D") contractor. As of September 30, 2013, long term receivables from DOE were $25.8 million, or $80.8 million net of valuation allowances of $55.0 million. The receivable for DOE's share of pension and postretirement benefits costs has a full valuation allowance due to USEC's inability to reach a resolution with DOE, the uncertainty of the timing for collection of amounts owed, and the potential of additional amounts owed by DOE. As noted in Note 15, USEC has potential pension plan funding obligations under Section 4062(e) of the Employee Retirement Income Security Act (“ERISA”) related to USEC's de-lease of the Portsmouth gaseous diffusion facilities and transition of employees to DOE's D&D contractor and related to the transition of employees in connection with the Paducah GDP transition. USEC believes that DOE is responsible for a significant portion of any pension and postretirement benefit costs associated with the transition of employees at Portsmouth.

Inventories

Inventories	9 Months Ended
	Sep. 30, 2013
Inventory, Net [Abstract]	'
Inventories	'
	INVENTORIES
	USEC is a supplier of low enriched uranium (“LEU”) for nuclear power plants. LEU consists of two components: separative work units (“SWU”) and uranium. SWU is a standard unit of measurement that represents the effort required to transform a given amount of natural uranium into two components: enriched uranium having a higher percentage of U235 and depleted uranium having a lower percentage of U235. The SWU contained in LEU is calculated using an industry standard formula based on the physics of enrichment. The amount of enrichment deemed to be contained in LEU under this formula is commonly referred to as its SWU component and the quantity of natural uranium deemed to be used in the production of LEU under this formula is referred to as its uranium component.
	USEC holds uranium, principally at the Paducah GDP, 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. Costs included in inventory include purchase costs and previous production costs at the Paducah GDP.
	Components of inventories follow (in millions):
		September 30, 2013						December 31, 2012
		Current		Current		Inventories, Net		Current		Current		Inventories, Net
		Assets		Liabilities				Assets		Liabilities
				(a)						(a)
	Separative work units	$	827.6	$	225.7	$	601.9	$	880.9	$	382.7	$	498.2
	Uranium	345		250.2		94.8		703.7		567.3		136.4
	Materials and supplies	4.2		—		4.2		8.6		—		8.6
		$	1,176.80	$	475.9	$	700.9	$	1,593.20	$	950	$	643.2
	(a)	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.
	Uranium Provided by Customers and Suppliers
	USEC held uranium with estimated values of approximately $1.5 billion at September 30, 2013, and $1.9 billion at December 31, 2012, to which title was held by customers and suppliers and for which no assets or liabilities were recorded on the balance sheet. The reduction reflects a 19% decline in the uranium spot price indicator and a 5% decline in quantities. Utility customers provide uranium to USEC as part of their enrichment contracts. Title to uranium provided by customers generally remains with the customer until delivery of LEU at which time title to LEU is transferred to the customer, and title to uranium is transferred to USEC.

Property_Plant_and_Equipment_P

Property, Plant and Equipment Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2013
Property, Plant and Equipment [Abstract]	'
Property, Plant and Equipment Disclosure	'
	7. PROPERTY, PLANT AND EQUIPMENT
	A summary of changes in property, plant and equipment follows (in millions):
		December 31,			Capital Expenditures (Depreciation)			Transfers and Retirements			Ceasing of Enrichment at Paducah			September 30,
		2012												2013
	Construction work in progress	$	2.7		$	—		$	(0.6	)	$	(1.7	)	$	0.4
	Leasehold improvements	183.7			—			(42.3		)	—			141.4
	Machinery and equipment	181.7			—			(15.0		)	—			166.7
		368.1			—			(57.9		)	(1.7		)	308.5
	Accumulated depreciation and amortization	(317.1		)	(16.2		)	55.4			(17.6		)	(295.5		)
		$	51		$	(16.2	)	$	(2.5	)	$	(19.3	)	$	13
	As noted in Note 3, USEC incurred a charge to cost of sales of $19.3 million in the nine months ended September 30, 2013 in connection with the ceasing of enrichment at the Paducah GDP and the related retirements of property, plant and equipment used in the enrichment process.

Deferred_Revenue_and_Advances_

Deferred Revenue and Advances From Customers	9 Months Ended
	Sep. 30, 2013
Deferred Revenue and Credits, Current [Abstract]	'
Deferred Revenue and Advances From Customers	'
	DEFERRED REVENUE AND ADVANCES FROM CUSTOMERS
		September 30,		December 31,
		2013		2012
		(millions)
	Deferred revenue	$	163.7	$	123.1
	Advances from customers	—		2.4
		$	163.7	$	125.5
	Deferred costs associated with deferred revenue	$	136.6	$	116.8

Debt

Debt	9 Months Ended
	Sep. 30, 2013
Line of Credit Facility [Abstract]	'
Debt	'
	DEBT
	Credit Facility
	USEC's $110.0 million credit facility matured on September 30, 2013 and was not renewed or replaced. Letters of credit as of September 30, 2013 remain outstanding until their maturity. Utilization of the credit facility at September 30, 2013 and December 31, 2012 follows:
		September 30,		December 31,
		2013		2012
		(millions)
	Borrowings under the revolving credit facility	$	—	$	—
	Term loan	—		83.2
	Letters of credit	1.6		14.7
	Available credit	—		87.1
	Convertible Senior Notes due 2014
	Convertible senior notes amounted to $530.0 million as of September 30, 2013 and December 31, 2012. The convertible senior notes are due October 1, 2014. Interest of 3.0% is payable semi-annually in arrears and is due by April 1 and October 1 of each year. The notes were not eligible for conversion to common stock as of September 30, 2013 or December 31, 2012.
	Deferred Financing Costs
	Financing costs are generally deferred and amortized over the life of the instrument. A summary of deferred financing costs for the nine months ended September 30, 2013 follows (in millions):
		December 31,		Additions		Reductions			September 30,
		2012							2013
	Other current assets:
	Bank credit facilities	$	3	$	2.1	$	(5.1	)	$	—
	Deferred financing costs (long-term):
	Convertible notes	$	3.6	$	—	$	(1.5	)	$	2.1

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	10. FAIR VALUE MEASUREMENTS
	Pursuant to the accounting guidance for fair value measurements, fair value is defined 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.
	Fair Value Hierarchy
	The accounting guidance for fair value measurement also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The standard establishes a fair value hierarchy based on the level of independent, objective evidence surrounding the inputs used to measure fair value. A financial instrument’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The fair value hierarchy is as follows:
	•	Level 1 – quoted prices in active markets for identical assets or liabilities.
	•	Level 2 – inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices in active markets for similar assets or liabilities, quoted prices for identical or similar assets or liabilities in markets that are not active, or model-derived valuations in which significant inputs are observable or can be derived principally from, or corroborated by, observable market data.
	•	Level 3 – unobservable inputs in which little or no market data exists.
	Financial Instruments Recorded at Fair Value
		Fair Value Measurements
		(in millions)
		September 30, 2013												December 31, 2012
		Level 1		Level 2			Level 3			Total				Level 1	Level 2		Level 3	Total
	Assets:
	Cash equivalents (a)	—		$	127.9		—			$	127.9			—	$	292.2	—	$	292.2
	Deferred compensation asset (b)	—		3			—			3				—	2.7		—	2.7
	Liabilities:
	Deferred compensation obligation (b)	—		2.8			—			2.8				—	2.7		—	2.7
	(a)	Cash equivalents consist of funds invested in institutional money market funds. These investments are classified within Level 2 of the valuation hierarchy because unit prices of institutional funds are estimated prices using observable, market-based inputs.
	(b)	The deferred compensation obligation represents the balance of deferred compensation plus net investment earnings. The deferred compensation plan is informally funded through a rabbi trust using variable universal life insurance. The cash surrender value of the life insurance policies is designed to track the deemed investments of the plan participants. Investment crediting options consist of institutional and retail investment funds. The deemed investments are classified within Level 2 of the valuation hierarchy because (i) of the indirect method of investing and (ii) unit prices of institutional funds are not quoted in active markets.
	Other Financial Instruments
	As of September 30, 2013 and December 31, 2012, the balance sheet carrying amounts for accounts receivable, accounts payable and accrued liabilities (excluding the deferred compensation obligation described above), and payables under the commercial agreement (the “Russian Contract”) with a Russian government entity known as Techsnabexport (“TENEX”) approximate fair value because of the short-term nature of the instruments.
	The balance sheet carrying amounts and estimated fair values of USEC’s debt follow (in millions):
		September 30, 2013						31-Dec-12
		Carrying Value			Fair Value			Carrying Value				Fair Value
	Credit facility term loan	$	—		$	—		$	83.2			$	93.5
	Convertible preferred stock and accrued dividends payable-in-kind	110.4			110.4			100.5				100.5
	3.0% convertible senior notes, due October 1, 2014	530			140.5			530				198.2
	The estimated fair values of the term loans are based on the change in market value of an index of loans of similar credit quality based on published credit ratings, and are classified as using Level 2 inputs in the fair value measurement.
	The convertible preferred stock can be converted or sold at the holder’s option and is classified as a current liability at the redemption value. The estimated fair value of the convertible preferred stock is based on a market approach using a discount rate of 12.75%, which is unobservable (Level 3) since the instruments do not trade. Dividends on the convertible preferred stock are paid (or accrued and are added to the liquidation preference of the convertible preferred stock) as additional shares of convertible preferred stock on a quarterly basis at an annual rate of 12.75%, which is consistent with current market prices and other market benchmarks. The estimated fair value equals the redemption value of $1,000 per share. The convertible preferred stock are currently subject to a share issuance limitation. 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 estimated fair value of the convertible notes is based on the trading price as of the balance sheet date, and is classified as using Level 1 inputs in the fair value measurement.

Pension_and_Postretirement_Hea

Pension and Postretirement Health and Life Benefits	9 Months Ended
	Sep. 30, 2013
General Discussion of Pension and Other Postretirement Benefits [Abstract]	'
Pension and Postretirement Health and Life Benefits	'
	PENSION AND POSTRETIREMENT HEALTH AND LIFE BENEFITS
	The components of net benefit costs for pension and postretirement health and life benefit plans were as follows (in millions):
		Defined Benefit Pension Plans												Postretirement Health and Life Benefit Plans
		Three Months Ended						Nine Months Ended						Three Months Ended						Nine Months Ended
		September 30,						September 30,						September 30,						September 30,
		2013			2012			2013			2012			2013			2012			2013			2012
	Service costs	$	1.4		$	3.6		$	8.8		$	10.9		$	0.9		$	0.9		$	2.7		$	2.7
	Interest costs	11.5			12.1			33.5			36.2			2.2			2.7			6.7			8.3
	Expected returns on plan assets (gains)	(12.8		)	(12.9		)	(38.3		)	(38.9		)	(0.5		)	(0.7		)	(1.7		)	(2.1		)
	Amortization of prior service costs	—			0.3			0.7			1.1			—			—			—			—
	Amortization of actuarial (gains) losses, net	2			5			14.2			14.8			0.6			1.2			2			3.4
	Curtailment (gains)	—			—			(0.7		)	—			—			—			—			—
	Net benefit costs	$	2.1		$	8.1		$	18.2		$	24.1		$	3.2		$	4.1		$	9.7		$	12.3
	USEC expects to contribute $24.1 million to the defined benefit pension plans in 2013, including $20.9 million of required contributions under ERISA and $2.5 million to non-qualified plans. USEC has contributed $16.2 million in the nine months ended September 30, 2013.
	There is no required contribution for the postretirement health and life benefit plans under ERISA and USEC does not expect to contribute in 2013. USEC receives federal subsidy payments for sponsoring prescription drug benefits that are at least actuarially equivalent to Medicare Part D.
	Effective August 5, 2013, accrued benefits for active employees who are not covered by a collective bargaining agreement have been frozen under the defined benefit pension plans. The retirement benefit is fixed and will no longer increase based on service or earnings. The freeze of the defined benefit pension plans is part of the internal organizational structure review effort. The defined benefit pension plans were amended to allow a lump sum payment option to active employees who are not covered by a collective bargaining agreement who are terminated as a result of participation in a reduction in force from August 5, 2013 through December 31, 2014. The defined benefit pension plans were further amended to allow a one-time voluntary election for a lump sum payment in December 2013 to certain former employees with deferred vested pension benefits. Any lump sum distributions would fully settle USEC's long-term pension obligations related to those benefits. Settlement charges may be recognized in the fourth quarter of 2013 or 2014 related to the immediate recognition of actuarial losses accumulated in other comprehensive income, a component of stockholders' equity.
	A curtailment occurs when an employer eliminates accrual of pension benefits for some or all future services of a significant number of employees covered by the pension plan. When a curtailment occurs, plan assets and benefit obligations are remeasured. The remeasurement date for the curtailment was June 30, 2013. The net effect of the curtailment on the net periodic cost was a gain of $0.7 million and a decrease of $138.3 million on the pension liability (unfunded status) and accumulated other comprehensive income. USEC will continue to review further potential curtailment accounting impacts for those employees severed during 2013 and anticipated to be severed in the immediate future as part of workforce reductions.
	The key economic assumptions for the June 30, 2013 remeasurement have changed from the December 31, 2012 measurement. The discount rate used at June 30, 2013 is 4.92% compared to 4.07% used at December 31, 2012, the salary growth rate remained the same at 4.00%, and the expected return on assets also remained the same at 6.75%. The expected contributions to the pension plans for 2013 remain the same.
	Prior to the start of 2012, a significant portion of the costs related to pension and postretirement health and life benefit plans were attributed to Portsmouth contract services, based on the employee base performing contract services work. Starting in 2012, ongoing retiree benefit costs related to USEC's former Portsmouth employees are charged to the LEU segment rather than the contract services segment based on our continuing LEU segment operations that support our active and retired employees. These net benefit costs totaled $7.5 million for the nine months ended September 30, 2013 and $9.9 million for the nine months ended September 30, 2012 and are directly charged to cost of sales rather than production.
	Net periodic benefit costs related to continued operations are allocated to SWU inventory costs, selling, general and administrative expense, and advanced technology costs.
	Other Plans
	Effective August 5, 2013, certain employees impacted by the pension freeze discussed above will be eligible to receive an enhanced matching contribution formula under the USEC Savings Program (401(k) plan). USEC's maximum matching contribution for these individuals was increased from 4% to 7% of eligible earnings in August.

StockBased_Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2013
Share-based Compensation [Abstract]	'
Stock-Based Compensation	'
	STOCK-BASED COMPENSATION
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2013		2012		2013		2012
		(millions)
	Total stock-based compensation costs:
	Restricted stock and restricted stock units	$	0.3	$	0.7	$	1.6	$	3.2
	Stock options, performance awards and other	—		0.1		0.1		0.6
	Less: costs capitalized as part of inventory	—		—		—		(0.1		)
	Expense included in selling, general and administrative and advanced technology costs	$	0.3	$	0.8	$	1.7	$	3.7
	Total recognized tax benefit	$	—	$	—	$	—	$	—
	The total recognized tax benefit is reported at the federal statutory rate net of the tax valuation allowance.
	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. There was no stock-based compensation granted in the nine months ended September 30, 2013. As of September 30, 2013, there was $1.1 million of unrecognized compensation cost, adjusted for estimated forfeitures, related to non-vested restricted shares and restricted stock units granted. That cost is expected to be recognized over a weighted-average period of 1.2 years.
	On January 10, 2013, the Compensation Committee of the Board of Directors approved the surrender and cancellation of 2,462,726 unexercised stock options and suspended the Annual Incentive Program and Long Term Incentive Program for 2013 under the USEC Inc. 2009 Equity Incentive Plan.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	INCOME TAXES
	Because there is a full valuation allowance against deferred tax assets and there are pretax losses from continuing operations and income in other components of the financial statements (e.g., discontinued operations and other comprehensive income), the income tax benefit from pretax losses from continuing operations is limited to the amount of income tax expense recorded on all items other than continuing operations. The income tax benefit from continuing operations consists primarily of the income tax benefit calculated using an estimated annual effective tax rate. The estimated annual effective tax rate applied to pretax losses from continuing operations for the interim period is calculated using the estimated full-year plan for ordinary income and the year-to-date amounts for discontinued operations and other comprehensive income. The income tax expense on all items other than continuing operations is recorded discretely based on year-to-date amounts. The difference in calculating the income tax expense and income tax benefit of $14.9 million is an interim timing difference recorded on the balance sheet in current liabilities that will reverse by year end when full-year results are presented.

Net_Income_Per_Share

Net Income Per Share	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Net Income (Loss) Per Share	'
	NET INCOME (LOSS) PER SHARE
	Basic net income (loss) per share is calculated by dividing net income (loss) by the weighted average number of shares of common stock outstanding during the period, excluding any unvested restricted stock. In calculating diluted net income per share, the numerator is increased by interest expense on the convertible notes and convertible preferred stock dividends, net of amount capitalized and net of tax, and the denominator is increased by the weighted average number of shares resulting from potentially dilutive securities, assuming full conversion, consisting of stock compensation awards, convertible notes, convertible preferred stock and warrants. No dilutive effect is recognized in a period in which a net loss has occurred or in which the assumed conversion effect of convertible securities is antidilutive.
	On July 1, 2013, USEC effectuated a reverse stock split of 1-for-25 shares in order to regain compliance with the NYSE continued listing criteria related to minimum share price. Net income (loss) per share was adjusted for all periods presented to reflect the change in the number of shares.
		Three Months Ended							Nine Months Ended
		September 30,							September 30,
		2013				2012			2013				2012
		(millions)
	Numerators:
	Net income (loss) from continuing operations	$	(44.3	)		$	5		$	(108.9	)		$	(116.4	)
	Net income (loss) from discontinued operations	—				(0.5		)	21.7				0.1
	Net income (loss)	$	(44.3	)		$	4.5		$	(87.2	)		$	(116.3	)
	Numerators for diluted calculations (a):
	Net income (loss) from continuing operations	$	(44.3	)		$	5		$	(108.9	)		$	(116.4	)
	Net income (loss) from discontinued operations	—				(0.5		)	21.7				0.1
	Net income (loss)	$	(44.3	)		$	4.5		$	(87.2	)		$	(116.3	)
	Denominator:
	Weighted average common shares	5				5			5				5
	Less: Weighted average unvested restricted stock	0.1				0.1			0.1				0.1
	Denominator for basic calculation	4.9				4.9			4.9				4.9
	Weighted average effect of dilutive securities:
	Convertible notes	1.8				1.8			1.8				1.8
	Convertible preferred stock:
	Equivalent common shares (b)	13.7				4.3			10.5				3.5
	Less: share issuance limitation (c)	12.8				3.4			9.6				2.6
	Net allowable common shares	0.9				0.9			0.9				0.9
	Subtotal	2.7				2.7			2.7				2.7
	Less: shares excluded in a period of a net loss or antidilution	2.7				2.7			2.7				2.7
	Weighted average effect of dilutive securities	—				—			—				—
	Denominator for diluted calculation	4.9				4.9			4.9				4.9
	Net income (loss) per share from continuing operations – basic and diluted	$	(9.04	)		$	1.02		$	(22.22	)		$	(23.75	)
	Net income (loss) per share from discontinued operations – basic and diluted	$	—			$	(0.10	)	$	4.43			$	0.02
	Net income (loss) per share – basic and diluted	$	(9.04	)		$	0.92		$	(17.79	)		$	(23.73	)
	(a)	The numerators are subject to increase for interest expense on convertible notes and convertible preferred stock dividends, net of tax, of $5.1 million in the three months ended September 30, 2013 and $15.2 million in the nine months ended September 30, 2013. The tax rate is the statutory rate. Net interest expense on convertible notes and convertible preferred stock dividends was $4.9 million in the three months ended September 30, 2012 and $14.4 million in the nine months ended September 30, 2012.
	However, no dilutive effect is recognized in a period in which a net loss has occurred. In addition, for purposes of calculating income from discontinued operations per share, the calculation of (loss) from continuing operations per share provides a control number in determining whether potential common shares are dilutive or antidilutive. The control number concept requires that the same number of potentially dilutive securities applied in computing diluted earnings per share from continuing operations be applied to all other categories of income or loss (discontinued operations and net income/loss), regardless of their antidilutive effect on such categories. Therefore, no dilutive effect is recognized in the calculation of income from discontinued operations per share.
	(b)	The number of equivalent common shares for the convertible preferred stock is based on the arithmetic average of the daily volume weighted average prices per share of common stock for each of the last 20 trading days, and is determined as of the beginning of the period for purposes of calculating diluted net income per share.
	(c)	Prior to obtaining shareholder approval, the preferred stock may not be converted into an aggregate number of shares of common stock in excess of 19.99% of the shares of our common stock outstanding on May 25, 2010 (approximately 0.9 million shares adjusted to take into account the 1-for-25 reverse stock split), in compliance with the rules of the New York Stock Exchange. 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.
	Options and warrants to purchase shares of common stock having an exercise price greater than the average share market price are excluded from the calculation of diluted net income per share:
		Three Months Ended									Nine Months Ended
		September 30,									September 30,
		2013					2012				2013					2012
	Options excluded from diluted net income per share	1,000					111,000				1,000					111,000
	Warrants excluded from diluted net income per share	250,000					250,000				250,000					250,000
	Exercise price of excluded options	$	177.5		to		$	93	to		$	177.5		to		$	93	to
		$	357				$	357			$	357				$	357
	Exercise price of excluded warrants	$	187.5				$	187.5			$	187.5				$	187.5

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	COMMITMENTS AND CONTINGENCIES
	American Centrifuge Plant
	Project Funding
	USEC expects cumulative spending for the RD&D program for the period June 1, 2012 through December 31, 2013 to be approximately $320 million. The cooperative agreement for the RD&D program provides for 80% DOE and 20% USEC cost sharing for work performed during this period. DOE’s contribution is incrementally funded and DOE has provided funding of $241.3 million. Although this funding is not sufficient to fund the RD&D program through December 2013, the most recent amendment to the cooperative agreement in October 2013, which provided $13.6 million of additional government funding, states that there is an expectation that DOE would provide additional funding for the RD&D program for the funding period ending December 31, 2013. The government fiscal year 2014 continuing appropriations resolution passed by Congress and signed by the President on October 16, 2013 provided for continued funding for the U.S. government from October 1, 2013 through January 15, 2014. This resolution continued funding for the RD&D program at the government fiscal year 2013 annual rate of $110 million, less any automatic spending cuts applied to U.S. government spending. USEC believes that this level of funding, if provided, will be sufficient to fund the RD&D program through December 31, 2013 and achieve the remaining technical milestones. There is no assurance that additional funding will be made available. DOE’s remaining cost share is conditioned upon USEC continuing to meet all milestones and deliverables on schedule, USEC continuing to demonstrate to DOE’s satisfaction its ability to meet future milestones, and the availability of such government funding. Additional details regarding the RD&D program are provided in Note 4.
	The economics of the project are severely challenged by the current supply/demand imbalance in the market for low enriched uranium and related downward pressure on market prices for SWU which are now at their lowest levels in more than a decade. At current market prices USEC does not believe its plans for commercialization of the American Centrifuge project are economically viable without additional government support. In addition, USEC does not currently have any funding in place for the project following the completion of the current RD&D program in December 2013 and anticipates that funding will be needed for the project for the period from completion of the RD&D program until the receipt of financing for commercial deployment. The amount of any such funding would depend on the level of operations, manufacturing and other project infrastructure that is to be maintained in order to support a potential future ramp up to commercialization as well as the length of time until financing could be obtained for the plant. USEC is evaluating and pursuing the feasibility of alternatives and the actions necessary to proceed with the commercial deployment of the American Centrifuge technology, including the availability of additional government support and has initiated discussions with DOE regarding the project’s need for this support. However, USEC has no assurance that it will be successful in achieving any of these measures or the timing thereof. In light of USEC’s liquidity, USEC does not have the ability to continue to fund the American Centrifuge project at its current levels beyond the end of 2013 without additional government support and even with this support USEC’s ability to provide funding in 2014 will be limited. Therefore, USEC continues to evaluate its options concerning the American Centrifuge project, including its ability to continue the project prior to or upon completion of the RD&D program, further demobilization of or delays in the commercial deployment of the project, and termination of the project, and could make a decision to demobilize or terminate the project in the near term. Any such actions may have a material adverse impact on USEC's ability to deploy the American Centrifuge technology, on its liquidity and on the long-term viability of its enrichment business.
	Significant additional financing is needed to commercially deploy the American Centrifuge Plant ("ACP"). However, in order to successfully raise this capital, USEC needs to develop and validate a viable business plan that supports loan repayment and provides potential investors with an attractive return on investment based on the project's risk profile. Factors that can affect this plan include key variables related to project cost, schedule, market demand and market prices for low enriched uranium, financing costs and other financing terms. USEC has experienced cost pressures due to delays in deployment of the project.
	USEC has been pursuing a loan guarantee under the DOE Loan Guarantee Program, which was established by the Energy Policy Act of 2005, in order to obtain the funding needed to complete the ACP. In July 2008, USEC applied under the DOE Loan Guarantee Program for $2 billion in U.S. government guaranteed debt financing for the ACP. Instead of moving forward with a conditional commitment for a loan guarantee, in the fall of 2011, DOE proposed a two-year RD&D program for the project. DOE indicated that USEC's application for a DOE loan guarantee would remain pending during the RD&D program but has given USEC no assurance that a successful RD&D program will result in a loan guarantee. In order to obtain a loan guarantee, USEC will need to demonstrate a viable commercialization plan which is dependent on the factors described above. Additional capital beyond the $2 billion of DOE loan guarantee funding that USEC has applied for and USEC's internally generated cash flow also would be required to complete the project. USEC has had discussions with Japanese export credit agencies regarding financing up to $1 billion of the cost of completing the ACP, with such potential financing predicated on USEC receiving a DOE loan guarantee.
	In addition to the DOE loan guarantee and the Japanese export credit agency funding discussed above, USEC anticipates that it would need at least $1 billion of additional capital to complete the project. The amount of additional capital required would include contributions from USEC and would be dependent on a number of factors, including the amount of any revised cost estimate and schedule for the project, the amount of contingency or other capital DOE would require as part of a loan guarantee, and the amount of the DOE credit subsidy cost that would be required to be paid in connection with a loan guarantee. USEC anticipates that under such a financing plan the potential sources for this capital could include cash generated by the project during startup, available USEC cash flow from operations and additional third-party capital. USEC would expect that the additional third-party capital would be raised at the project level, including through the issuance of additional equity participation.
	As described above, current enrichment market conditions do not support a viable business plan for obtaining the capital necessary for commercialization of the American Centrifuge project without additional government support. If USEC is able to obtain the additional government support needed to proceed with the financing and commercial deployment of the ACP, USEC also is uncertain regarding the amount of internally generated cash flow from operations that USEC will have available to fund the project in light of the delays in deployment of the project, reduced cash flow from operations as a result of ceasing enrichment at the Paducah GDP and potential requirements for USEC's internally generated cash flow to satisfy its pension and postretirement benefit and other obligations. The amount of capital that USEC would be able to contribute to the project going forward would impact USEC's share of the ultimate ownership of the project, which would be reduced as a result of raising equity and other capital to deploy the project.
	In order to address the October 1, 2014 maturity of its $530.0 million of convertible senior notes and increase the likelihood of a successful financing and deployment of the American Centrifuge project and USEC's participation in such project, USEC is engaged with its advisors and certain stakeholders on alternatives for a possible restructuring of its balance sheet. A restructuring of USEC's balance sheet would be expected to adversely affect the holders of USEC common stock through dilution or loss in value. However, USEC has no assurance regarding the outcome of any discussions USEC pursues with creditors or other key stakeholders.
	Milestones under the 2002 DOE-USEC Agreement
	USEC and DOE are parties to an agreement dated June 17, 2002, as amended (the “2002 DOE-USEC Agreement”), pursuant to which USEC and DOE made long-term commitments directed at resolving issues related to the stability and security of the domestic uranium enrichment industry. The agreement provides that USEC will develop, demonstrate and deploy advanced enrichment technology in accordance with milestones and provides for remedies in the event of a failure to meet a milestone under certain circumstances.
	The 2002 DOE-USEC Agreement provides DOE with specific remedies if USEC fails to meet a milestone that would materially impact USEC's ability to begin commercial operations of the American Centrifuge Plant on schedule and such delay was within USEC's control or was due to USEC's fault or negligence. These remedies could include terminating the 2002 DOE-USEC Agreement, revoking USEC's access to DOE's U.S. centrifuge technology that USEC requires for the success of the American Centrifuge project and requiring USEC to transfer certain of its rights in the American Centrifuge technology and facilities to DOE, and to reimburse DOE for certain costs associated with the American Centrifuge project. Any of these remedies under the 2002 DOE-USEC Agreement could have a material adverse impact on USEC's business.
	The 2002 DOE-USEC Agreement provides that if a delaying event beyond the control and without the fault or negligence of USEC occurs which would affect USEC's ability to meet an ACP milestone, DOE and USEC will jointly meet to discuss in good faith possible adjustments to the milestones as appropriate to accommodate the delaying event.
	Technical Milestones under the June 2012 Cooperative Agreement
	The June 2012 cooperative agreement with DOE, as amended, includes nine technical milestones for the RD&D program. As of September 30, 2013, six of the milestones have been completed and certified by DOE and the final three milestones are targeted for completion at the end of the RD&D program on December 31, 2013. DOE has the right to terminate the cooperative agreement if any of the remaining technical milestones are not met. DOE also has the right to terminate the cooperative agreement if USEC materially fails to comply with the other terms and conditions of the cooperative agreement.  Failure to meet the technical milestones under the cooperative agreement could provide a basis for DOE to exercise its remedies under the 2002 DOE-USEC Agreement.
	In addition, the cooperative agreement contains five non-binding performance indicators that are designed to be achieved throughout the RD&D program and ensure that the RD&D program is on track to achieve the milestones and other program objectives. Four of the five performance indicators have been completed and certified by DOE, and the final performance indicator has been completed and documentation has been submitted for certification by DOE. Although the performance indicators are non-binding, the failure to achieve a performance indicator could cause DOE to take actions that are adverse to USEC.
	2002 DOE-USEC Agreement - Domestic Enrichment Facilities
	Under the 2002 DOE-USEC Agreement, USEC agreed to operate the Paducah GDP at a production rate at or above 3.5 million SWU per year and production at Paducah may not be reduced below a minimum of 3.5 million SWU per year until six months before USEC has the permanent addition of 3.5 million SWU per year of new capacity installed based on advanced enrichment technology.  By letter dated May 30, 2013, USEC provided notice to DOE under the 2002 DOE-USEC Agreement that it would cease enrichment at the Paducah GDP at the conclusion of the agreements related to the one-year, multi-party depleted uranium enrichment program on May 31, 2013.  Under the 2002 DOE-USEC Agreement, DOE can transition operations of Paducah from USEC operation to ensure the continuity of domestic enrichment operations and the fulfillment of supply contracts.  USEC is in discussions with DOE regarding an agreement related to the transition of the Paducah GDP and while USEC believes maintaining USEC's access to the Paducah GDP would be the best course of action to permit the fulfillment of supply contracts, there can be no assurance that DOE will not seek to exercise this right in a manner that will result in material adverse impacts to USEC.
	NYSE Listing Standards Notices
	On May 8, 2012, USEC received notice from the NYSE that the average closing price of its common stock was below the NYSE's continued listing criteria relating to minimum share price. The NYSE listing requirements require that a company's common stock trade at a minimum average closing price of $1.00 over a consecutive 30 trading-day period.  On July 1, 2013, USEC effectuated a reverse stock split in order to regain compliance with the NYSE continued listing criteria related to minimum share price. This action resulted in USEC's closing share price exceeding $1.00 per share and remaining above that level, and the condition has now been cured.
	On April 30, 2013, USEC received notice from the NYSE that the decline in USEC's total market capitalization has caused it to be out of compliance with another of the NYSE's continued listing standards. The NYSE listing requirements require that a company maintain an average market capitalization of not less than $50 million over a consecutive 30 trading-day period where the company's total stockholders' equity is less than $50 million. In accordance with the NYSE's rules, USEC submitted a plan advising the NYSE of definitive action it has taken, or is taking, that would bring it into conformity with the market capitalization listing standards within 18 months of receipt of the letter. On August 1, 2013, the NYSE accepted USEC's plan of compliance and USEC's common stock will continue to be listed on the NYSE during the 18-month cure period, subject to the compliance with other NYSE continued listing standards and continued periodic review by the NYSE of USEC's progress with respect to its plan. USEC's plan outlines initiatives USEC must execute by quarter. These initiatives include the successful completion of American Centrifuge plant development milestones, the commercialization of the ACP, as well as the successful execution of the Company's Russian Supply Agreement and the Company's potential balance sheet restructuring.  The NYSE has notified us that if USEC does not achieve these financial and operational goals, the Company will be subject to NYSE trading suspension at the point the initiative or goal is not met.
	In addition, the NYSE can at any time suspend trading in a security and delist the stock if it deems it necessary for the protection of investors. The NYSE can take accelerated listing action if USEC's common stock trades at levels viewed to be “abnormally low” over a sustained period of time. USEC would also be subject to immediate suspension and de-listing from the NYSE if its average market capitalization is less than $15 million over a consecutive 30 trading-day period or if it were to file or announce an intent to file under any of the sections of the bankruptcy law. During July 2013, USEC's market capitalization fell below $15 million for several days. Even if USEC meets the numerical listing standards above, the NYSE reserves the right to assess the suitability of the continued listing of a company on a case-by-case basis whenever it deems it appropriate and will consider factors such as unsatisfactory financial conditions and/or operating results or inability to meet debt obligations or adequately finance operations.
	Under the terms of USEC's convertible notes, a "fundamental change" is triggered if USEC's shares of common stock are not listed for trading on any of the NYSE, the American Stock Exchange (now NYSE-MKT), the NASDAQ Global Market or the NASDAQ Global Select Market, and the holders of the notes can require USEC to repurchase the notes at par for cash. USEC has no assurance that it would be eligible for listing on an alternate exchange in light of its market capitalization, stockholders' deficit and net losses. USEC's receipt of a NYSE continued listing standards notification described above did not trigger a fundamental change. In the event a fundamental change under the convertible notes is triggered, USEC does not have adequate cash to repurchase the notes. A failure by USEC to offer to repurchase the notes or to repurchase the notes after the occurrence of a fundamental change is an event of default under the indenture governing the notes. Accordingly, the exercise of remedies by holders of USEC's convertible notes or the trustee for the notes as a result of a delisting would have a material adverse effect on USEC's liquidity and financial condition.
	Potential ERISA Section 4062(e) Liability
	USEC is in discussions with the Pension Benefit Guaranty Corporation (“PBGC”) regarding the impact of USEC's de-lease of the Portsmouth gaseous diffusion facilities and related transition of employees performing government services work to DOE's D&D contractor on September 30, 2011.  USEC notified the PBGC of this occurrence and the PBGC has informally advised USEC of its preliminary view that the Portsmouth site transition is a cessation of operations that triggers liability under ERISA Section 4062(e) and that its preliminary estimate is that the ERISA Section 4062(e) liability (computed taking into account the plan's underfunding on a termination basis, which amount differs from that computed for GAAP purposes) for the Portsmouth site transition is approximately $130 million. USEC has informed the PBGC that it does not agree that the Portsmouth de-lease and transition of employees constituted a cessation of operations that triggered liability under ERISA Section 4062(e). USEC also disputes the amount of the PBGC's preliminary calculation of the potential ERISA Section 4062(e) liability. In addition, USEC believes that DOE is responsible for a significant portion of any pension costs associated with the transition of employees at Portsmouth. However, USEC has not reached a resolution with the PBGC and USEC has no assurance that the PBGC will agree with it or will not pursue a requirement for it to accelerate funding or take other actions to provide security. USEC is also in discussions with the PBGC regarding the cessation of enrichment at the Paducah GDP and related transition of employees including reductions in force. In addition, a demobilization or termination of the American Centrifuge project could raise doubt about the long-term viability of USEC's enrichment business and the PBGC could take the position that a demobilization of the American Centrifuge project, either alone or taken together with actions related to the transition of the Paducah GDP, create potential liabilities under ERISA Section 4062(e).
	Legal Matters
	USEC is subject to various legal proceedings and claims, either asserted or unasserted, which arise in the ordinary course of business. While the outcome of these claims cannot be predicted with certainty, USEC does not believe that the outcome of any of these legal matters will have a material adverse effect on its results of operations, cash flows or financial condition.
	On June 27, 2011, a complaint was filed in the United States District Court for the Southern District of Ohio, Eastern Division, against USEC by a former Portsmouth GDP employee claiming that USEC owes severance benefits to him and other similarly situated employees that have transitioned or will transition to the DOE D&D contractor. The plaintiff amended its complaint on August 31, 2011 and February 10, 2012, among other things, to limit the purported class of similarly situated employees to salaried employees at the Portsmouth site who transitioned to the D&D contractor and are allegedly eligible for or owed benefits. On October 11, 2012, the United States District Court granted USEC’s motion to dismiss the complaint and dismissed Plaintiffs’ motion for class certification as moot. The Plaintiffs filed an appeal on January 18, 2013. On July 19, 2013, the U.S. Court of Appeals for the Sixth Circuit upheld the District Court decision and dismissed the Plaintiffs' appeal. The Plaintiffs have no further rights to appeal. USEC had not accrued any amounts for this matter.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2013
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'
Accumulated Other Comprehensive Income (Loss)	'
	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
	The sole component of accumulated other comprehensive income (loss) is pension and postretirement health and life benefit plans.
	Changes in accumulated other comprehensive income (loss) for the sole component follow (in millions).
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
	Beginning balance	$	(196.5	)	$	(254.3	)	$	(291.9	)	$	(262.5	)
	Gain arising during the period	—			—			138.3			—
	Amortization of actuarial (gains) losses, net (a)	2.6			6.2			15.5			18.2
	Amortization of prior service costs (a)	—			0.3			0.7			1.1
	Total reclassifications for the period, before tax	2.6			6.5			154.5			19.3
	Income tax (expense) benefit	(1.5		)	(2.4		)	(58.0		)	(7.0		)
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	1.1			4.1			96.5			12.3
	Ending balance	$	(195.4	)	$	(250.2	)	$	(195.4	)	$	(250.2	)
	(a)	These items reclassified from accumulated other comprehensive income (loss) are included in the computation of net benefit costs as detailed in Note 11.

Segment_Information

Segment Information	9 Months Ended
	Sep. 30, 2013
Segment Reporting Information, Revenue for Reportable Segment [Abstract]	'
Segment Information	'
	SEGMENT INFORMATION
	USEC has two reportable segments:  the LEU segment with two components, SWU and uranium, and the contract services segment. The LEU segment is USEC’s primary business focus and includes sales of the SWU component of LEU, sales of both the SWU and uranium components of LEU, and sales of uranium. The contract services segment consists of work performed for DOE and DOE contractors at the Portsmouth site and the Paducah GDP.  The contract services segment formerly included nuclear energy services and technologies provided by NAC International Inc. Refer to Note 2 regarding the sale of NAC in March 2013 and results of operations for NAC. Gross profit is USEC’s measure for segment reporting. There were no intersegment sales in the periods presented.
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
		(millions)
	Revenue
	LEU segment:
	Separative work units	$	295.8		$	559.5		$	853.4		$	1,444.60
	Uranium	3.8			—			45.3			3.6
		299.6			559.5			898.7			1,448.20
	Contract services segment	4.2			3.5			10.3			10.6
		$	303.8		$	563		$	909		$	1,458.80
	Segment Gross Profit (Loss)
	LEU segment	$	(30.8	)	$	36.7		$	(63.7	)	$	83.8
	Contract services segment	0.8			(0.1		)	0.1			(0.3		)
	Gross profit (loss)	$	(30.0	)	$	36.6		$	(63.6	)	$	83.5

Sale_of_NAC_Subsidiary_Tables

Sale of NAC Subsidiary (Tables)	9 Months Ended
	Sep. 30, 2013
Discontinued Operation, Additional Disclosures [Abstract]	'
Schedule of Discontinued Operations Income Statement Disclosures [Table Text Block]	'
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
		2013		2012			2013		2012
	Revenue	$	—	$	7.5		$	13.7	$	38
	Cost of sales	—		6.6			11.8		32.9
	Gross profit	—		0.9			1.9		5.1
	Advanced technology costs	—		0.2			—		0.6
	Selling, general and administrative	—		1.5			1.8		4.4
	Operating income (loss)	—		(0.8		)	0.1		0.1
	Gain on sale of subsidiary	—		—			35.6		—
	Income (loss) before income taxes	—		(0.8		)	35.7		0.1
	Provision (benefit) for income taxes	—		(0.3		)	14		—
	Net income (loss) from discontinued operations	$	—	$	(0.5	)	$	21.7	$	0.1

Accounts_Receivable_Tables

Accounts Receivable (Tables)	9 Months Ended
	Sep. 30, 2013
Accounts Receivable, Net, Current [Abstract]	'
Schedule of Accounts Receivable	'
		September 30,		December 31,
		2013		2012
		(millions)
	Utility customers	$	121.3	$	118.3
	DOE pro-rata share of RD&D program funding	24.8		4.4
	Contract services, primarily DOE:
	Billed revenue	9.7		10.5
	Unbilled revenue	2.9		1.6
		12.6		12.1
	Current accounts receivable, net	$	158.7	$	134.8

Inventories_Tables

Inventories (Tables)	9 Months Ended
	Sep. 30, 2013
Inventory, Net [Abstract]	'
Schedule of Inventories	'
		September 30, 2013						December 31, 2012
		Current		Current		Inventories, Net		Current		Current		Inventories, Net
		Assets		Liabilities				Assets		Liabilities
				(a)						(a)
	Separative work units	$	827.6	$	225.7	$	601.9	$	880.9	$	382.7	$	498.2
	Uranium	345		250.2		94.8		703.7		567.3		136.4
	Materials and supplies	4.2		—		4.2		8.6		—		8.6
		$	1,176.80	$	475.9	$	700.9	$	1,593.20	$	950	$	643.2

Property_Plant_and_Equipment_P1

Property, Plant and Equipment Property, Plant and Equipment (Tables)	9 Months Ended
	Sep. 30, 2013
Property, Plant and Equipment [Abstract]	'
Property, Plant and Equipment	'
	A summary of changes in property, plant and equipment follows (in millions):
		December 31,			Capital Expenditures (Depreciation)			Transfers and Retirements			Ceasing of Enrichment at Paducah			September 30,
		2012												2013
	Construction work in progress	$	2.7		$	—		$	(0.6	)	$	(1.7	)	$	0.4
	Leasehold improvements	183.7			—			(42.3		)	—			141.4
	Machinery and equipment	181.7			—			(15.0		)	—			166.7
		368.1			—			(57.9		)	(1.7		)	308.5
	Accumulated depreciation and amortization	(317.1		)	(16.2		)	55.4			(17.6		)	(295.5		)
		$	51		$	(16.2	)	$	(2.5	)	$	(19.3	)	$	13

Deferred_Revenue_and_Advances_1

Deferred Revenue and Advances From Customers (Tables)	9 Months Ended
	Sep. 30, 2013
Deferred Revenue and Credits, Current [Abstract]	'
Schedule of Deferred Revenue and Advances from Customers	'
		September 30,		December 31,
		2013		2012
		(millions)
	Deferred revenue	$	163.7	$	123.1
	Advances from customers	—		2.4
		$	163.7	$	125.5
	Deferred costs associated with deferred revenue	$	136.6	$	116.8

Debt_Tables

Debt (Tables)	9 Months Ended
	Sep. 30, 2013
Line of Credit Facility [Abstract]	'
Schedule of Credit Facility	'
		September 30,		December 31,
		2013		2012
		(millions)
	Borrowings under the revolving credit facility	$	—	$	—
	Term loan	—		83.2
	Letters of credit	1.6		14.7
	Available credit	—		87.1
Summary of Deferred Financing Costs	'
		December 31,		Additions		Reductions			September 30,
		2012							2013
	Other current assets:
	Bank credit facilities	$	3	$	2.1	$	(5.1	)	$	—
	Deferred financing costs (long-term):
	Convertible notes	$	3.6	$	—	$	(1.5	)	$	2.1

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Schedule of Financial Instruments Recorded at Fair Value	'
	Financial Instruments Recorded at Fair Value
		Fair Value Measurements
		(in millions)
		September 30, 2013												December 31, 2012
		Level 1		Level 2			Level 3			Total				Level 1	Level 2		Level 3	Total
	Assets:
	Cash equivalents (a)	—		$	127.9		—			$	127.9			—	$	292.2	—	$	292.2
	Deferred compensation asset (b)	—		3			—			3				—	2.7		—	2.7
	Liabilities:
	Deferred compensation obligation (b)	—		2.8			—			2.8				—	2.7		—	2.7
Schedule of Fair Value of Debt	'
	The balance sheet carrying amounts and estimated fair values of USEC’s debt follow (in millions):
		September 30, 2013						31-Dec-12
		Carrying Value			Fair Value			Carrying Value				Fair Value
	Credit facility term loan	$	—		$	—		$	83.2			$	93.5
	Convertible preferred stock and accrued dividends payable-in-kind	110.4			110.4			100.5				100.5
	3.0% convertible senior notes, due October 1, 2014	530			140.5			530				198.2

Pension_and_Postretirement_Hea1

Pension and Postretirement Health and Life Benefits (Tables)	9 Months Ended
	Sep. 30, 2013
General Discussion of Pension and Other Postretirement Benefits [Abstract]	'
Schedule of Net Benefit Costs	'
		Defined Benefit Pension Plans												Postretirement Health and Life Benefit Plans
		Three Months Ended						Nine Months Ended						Three Months Ended						Nine Months Ended
		September 30,						September 30,						September 30,						September 30,
		2013			2012			2013			2012			2013			2012			2013			2012
	Service costs	$	1.4		$	3.6		$	8.8		$	10.9		$	0.9		$	0.9		$	2.7		$	2.7
	Interest costs	11.5			12.1			33.5			36.2			2.2			2.7			6.7			8.3
	Expected returns on plan assets (gains)	(12.8		)	(12.9		)	(38.3		)	(38.9		)	(0.5		)	(0.7		)	(1.7		)	(2.1		)
	Amortization of prior service costs	—			0.3			0.7			1.1			—			—			—			—
	Amortization of actuarial (gains) losses, net	2			5			14.2			14.8			0.6			1.2			2			3.4
	Curtailment (gains)	—			—			(0.7		)	—			—			—			—			—
	Net benefit costs	$	2.1		$	8.1		$	18.2		$	24.1		$	3.2		$	4.1		$	9.7		$	12.3

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2013
Share-based Compensation [Abstract]	'
Schedule of Stock-Based Compensation Costs	'
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2013		2012		2013		2012
		(millions)
	Total stock-based compensation costs:
	Restricted stock and restricted stock units	$	0.3	$	0.7	$	1.6	$	3.2
	Stock options, performance awards and other	—		0.1		0.1		0.6
	Less: costs capitalized as part of inventory	—		—		—		(0.1		)
	Expense included in selling, general and administrative and advanced technology costs	$	0.3	$	0.8	$	1.7	$	3.7
	Total recognized tax benefit	$	—	$	—	$	—	$	—

Net_Income_Per_Share_Tables

Net Income Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Schedule of Net Income Per Share	'
		Three Months Ended							Nine Months Ended
		September 30,							September 30,
		2013				2012			2013				2012
		(millions)
	Numerators:
	Net income (loss) from continuing operations	$	(44.3	)		$	5		$	(108.9	)		$	(116.4	)
	Net income (loss) from discontinued operations	—				(0.5		)	21.7				0.1
	Net income (loss)	$	(44.3	)		$	4.5		$	(87.2	)		$	(116.3	)
	Numerators for diluted calculations (a):
	Net income (loss) from continuing operations	$	(44.3	)		$	5		$	(108.9	)		$	(116.4	)
	Net income (loss) from discontinued operations	—				(0.5		)	21.7				0.1
	Net income (loss)	$	(44.3	)		$	4.5		$	(87.2	)		$	(116.3	)
	Denominator:
	Weighted average common shares	5				5			5				5
	Less: Weighted average unvested restricted stock	0.1				0.1			0.1				0.1
	Denominator for basic calculation	4.9				4.9			4.9				4.9
	Weighted average effect of dilutive securities:
	Convertible notes	1.8				1.8			1.8				1.8
	Convertible preferred stock:
	Equivalent common shares (b)	13.7				4.3			10.5				3.5
	Less: share issuance limitation (c)	12.8				3.4			9.6				2.6
	Net allowable common shares	0.9				0.9			0.9				0.9
	Subtotal	2.7				2.7			2.7				2.7
	Less: shares excluded in a period of a net loss or antidilution	2.7				2.7			2.7				2.7
	Weighted average effect of dilutive securities	—				—			—				—
	Denominator for diluted calculation	4.9				4.9			4.9				4.9
	Net income (loss) per share from continuing operations – basic and diluted	$	(9.04	)		$	1.02		$	(22.22	)		$	(23.75	)
	Net income (loss) per share from discontinued operations – basic and diluted	$	—			$	(0.10	)	$	4.43			$	0.02
	Net income (loss) per share – basic and diluted	$	(9.04	)		$	0.92		$	(17.79	)		$	(23.73	)
Schedule of Securities Excluded from Net Income Per Share	'
	Options and warrants to purchase shares of common stock having an exercise price greater than the average share market price are excluded from the calculation of diluted net income per share:
		Three Months Ended									Nine Months Ended
		September 30,									September 30,
		2013					2012				2013					2012
	Options excluded from diluted net income per share	1,000					111,000				1,000					111,000
	Warrants excluded from diluted net income per share	250,000					250,000				250,000					250,000
	Exercise price of excluded options	$	177.5		to		$	93	to		$	177.5		to		$	93	to
		$	357				$	357			$	357				$	357
	Exercise price of excluded warrants	$	187.5				$	187.5			$	187.5				$	187.5

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2013
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'
Accumulated Other Comprehensive Income (Loss) [Table Text Block]	'
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
	Beginning balance	$	(196.5	)	$	(254.3	)	$	(291.9	)	$	(262.5	)
	Gain arising during the period	—			—			138.3			—
	Amortization of actuarial (gains) losses, net (a)	2.6			6.2			15.5			18.2
	Amortization of prior service costs (a)	—			0.3			0.7			1.1
	Total reclassifications for the period, before tax	2.6			6.5			154.5			19.3
	Income tax (expense) benefit	(1.5		)	(2.4		)	(58.0		)	(7.0		)
	Amounts reclassified from accumulated other comprehensive income (loss), net of tax	1.1			4.1			96.5			12.3
	Ending balance	$	(195.4	)	$	(250.2	)	$	(195.4	)	$	(250.2	)

Segment_Information_Tables

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2013
Segment Reporting Information, Revenue for Reportable Segment [Abstract]	'
Segment Reporting Information	'
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
		(millions)
	Revenue
	LEU segment:
	Separative work units	$	295.8		$	559.5		$	853.4		$	1,444.60
	Uranium	3.8			—			45.3			3.6
		299.6			559.5			898.7			1,448.20
	Contract services segment	4.2			3.5			10.3			10.6
		$	303.8		$	563		$	909		$	1,458.80
	Segment Gross Profit (Loss)
	LEU segment	$	(30.8	)	$	36.7		$	(63.7	)	$	83.8
	Contract services segment	0.8			(0.1		)	0.1			(0.3		)
	Gross profit (loss)	$	(30.0	)	$	36.6		$	(63.6	)	$	83.5

Basis_of_Presentation_Narrativ

Basis of Presentation (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2013	Dec. 31, 2013
								Scenario, Forecast [Member]
Adjustments to Additional Paid in Capital, Stock Split	'	'	$12.50	'	'	'	'	'
Net loss	-44.3	4.5	-87.2	-116.3	1,200	491.1	'	'
Cash and cash equivalents	128.4	303.3	128.4	303.3	292.9	37.6	'	250
Long-Term Debt	530	'	530	'	530	'	'	'
Line of Credit Facility, Maximum Borrowing Capacity	'	'	'	'	'	'	$110	'
NYSE Minimum 30 Day Average Closing Price	$1	'	$1	'	'	'	'	'

Sale_of_NAC_Subsidiary_Details

Sale of NAC Subsidiary (Details) (USD $)	3 Months Ended			9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Contract services	$4.20	'	$3.50	$10.30	$10.60
Contract services costs	3.4	'	3.6	10.2	10.9
Gross profit	-30	'	36.6	-63.6	83.5
Advanced technology costs	44.5	'	44.9	150	167
Selling, general and administrative	11.2	'	11.3	36	38.1
Operating income	-53.3	'	13.5	-135	-88.1
Gain on sale of subsidiary	'	35.6	'	35.6	0
Segment, Discontinued Operations [Member]	'	'	'	'	'
Contract services	0	'	7.5	13.7	38
Contract services costs	0	'	6.6	11.8	32.9
Gross profit	0	'	0.9	1.9	5.1
Advanced technology costs	0	'	0.2	0	0.6
Selling, general and administrative	0	'	1.5	1.8	4.4
Operating income	0	'	-0.8	0.1	0.1
Gain on sale of subsidiary	0	'	0	35.6	0
Income before income taxes	0	'	-0.8	35.7	0.1
Provision for income taxes	0	'	-0.3	14	0
Net income from discontinued operations	$0	'	($0.50)	$21.70	$0.10

Sale_of_NAC_Subsidiary_Narrati

Sale of NAC Subsidiary (Narrative) (Details) (USD $)	3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2013	Sep. 30, 2013	Sep. 30, 2012	Mar. 15, 2013	Dec. 31, 2012
Discontinued Operation, Additional Disclosures [Abstract]	'	'	'	'	'
Goodwill	'	$0	'	$6.80	$6.80
Proceeds from sale of subsidiary	'	43.2	0	'	'
Gain on sale of subsidiary	35.6	35.6	0	'	'
Net assets and liabilities of subsidiary	'	'	'	5.5	'
Transaction costs for sale of subsidiary	'	'	'	$2.10	'

Transition_Charges_NarrativeDe

Transition Charges (Narrative)(Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Asset Retirement Charges	'	'	$19.30	'
Inventory Valuation Adjustments	5	'	15	'
Non-production expenses	47.7	6.1	123.4	12.7
Site expenses	37.4	'	63.8	'
Power Contract Losses	'	'	11.8	'
Accelerated property, plant and equipment expenses	5.3	2.8	13.5	2.8
Net defined benefit plan costs for former Portsmouth employees	'	3.3	7.5	9.9
One-time termination benefit costs	1.5	0.4	3.6	4
DOE Share of Paducah Termination Benefit Costs	6	'	'	'
Structuring advisory costs	2	1.1	6.7	7.1
Curtailment (gains)	0.7	'	'	'
Minimum [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated Total Paducah Termination Benefit Costs	23	'	'	'
Maximum [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated Total Paducah Termination Benefit Costs	27	'	'	'
Uranium Market Conditions [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Inventory Valuation Adjustments	'	'	5	'
Residual Uranium [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Inventory Valuation Adjustments	'	'	7.7	'
Materials and Supplies [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Inventory Valuation Adjustments	'	'	2.3	'
Workforce Reduction Phase One [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
One-time termination benefit costs	'	'	2	'
Payments for one-time termination benefits	'	'	2.5	'
DOE Share of Paducah Termination Benefit Costs	'	'	0.7	'
Workforce Reduction Phase Two [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
One-time termination benefit costs	1.6	'	'	'
DOE Share of Paducah Termination Benefit Costs	0.5	'	'	'
Workforce Reduction Phase Two [Member] | Minimum [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated Near-Term Termination Benefit Costs	1.6	'	'	'
Workforce Reduction Phase Two [Member] | Maximum [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Estimated Near-Term Termination Benefit Costs	$2.40	'	'	'

Advanced_Technology_Costs_and_1

Advanced Technology Costs and Other Income (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended	19 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2014	Dec. 31, 2013	Dec. 31, 2012
RD&D Program Qualifying Expenditures - DOE Share	$35.90	$34.60	$124.20	$44.60	'	'	'
Maximum funding for RD&D Program	'	'	'	'	'	350	'
Maximum funding for RD&D Program - Revised Estimate	'	'	'	'	'	320	'
Annual Rate of Authorized Government RD&D Program Funding	'	'	'	'	110	'	'
RD&D Program Funding by DOE	'	'	'	'	'	80.00%	'
RD&D Program Funding by USEC	'	'	'	'	'	20.00%	'
RD&D Program Funding by DOE To Date	'	'	'	'	'	241.3	'
RD&D Program Funding by DOE - Increment 1	'	'	'	'	'	87.7	'
RD&D Program Funding by DOE - Increment 2	'	'	'	'	'	45.7	'
RD&D Program Funding by DOE - Increment 3	'	'	'	'	'	44.4	'
RD&D Program Funding by DOE - Increment 4	'	'	'	'	'	49.9	'
RD&D Program Funding by DOE - Increment 5	'	'	'	'	'	13.6	'
RD&D Program Qualifying Expenditures To Date	270.2	'	270.2	'	'	'	'
RD&D Program Qualifying Expenditures To Date - DOE Share	216.2	'	216.2	'	'	'	'
RD&D Program Qualifying Expenditures To Date - DOE Share - Received	191.4	'	191.4	'	'	'	'
RD&D Program Qualifying Expenditures To Date - DOE Share - Receivable	24.8	4.4	24.8	4.4	'	'	'
RD&D Program Funding - DOE Advance	0	'	0	'	'	'	2.4
RD&D Program Qualifying Expenditures	'	'	155.1	55.7	'	'	'
Government [Member]	'	'	'	'	'	'	'
RD&D Program Qualifying Expenditures - DOE Share	'	'	$124.10	$44.60	'	'	'

Accounts_Receivable_Details

Accounts Receivable (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
In Millions, unless otherwise specified
Accounts Receivable, Net, Current [Abstract]	'	'	'
Utility Customer Receivables	$121.30	'	$118.30
DOE pro-rata share of RD&D program funding	24.8	'	4.4
Contract Services Billed Revenue	9.7	'	10.5
Contract Services Unbilled Revenue	2.9	'	1.6
Contract Services Customer Receivables	12.6	'	12.1
Accounts Receivable, Net	$158.70	$134.80	$134.80

Accounts_Receivable_Narrative_

Accounts Receivable (Narrative) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Valuation Allowances and Allowances for Doubtful Accounts	$1.80	$2.10
Government [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Accounts Receivable, Gross, Noncurrent	80.8	38
Valuation Allowances and Allowances for Doubtful Accounts	55	12.2
Accounts Receivable, Net, Noncurrent	25.8	25.8
Government - portion related to retiree benefits [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Accounts Receivable, Gross, Noncurrent	$42.80	'

Inventories_Details

Inventories (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Inventory, Net [Abstract]	'	'
Separative work units inventory	$827.60	$880.90
Uranium inventory	345	703.7
Materials and supplies	4.2	8.6
Inventories	1,176.80	1,593.20
Separative work units owed to customers and suppliers	225.7	382.7
Uranium owed to customers and suppliers	250.2	567.3
Inventories owed to customers and suppliers	475.9	950
Separative work units net of liability	601.9	498.2
Uranium inventory net of liability	94.8	136.4
Inventories, net	$700.90	$643.20

Inventories_Narrative_Details

Inventories (Narrative) (Details) (USD $)	9 Months Ended
In Billions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Inventory, Net [Abstract]	'	'
Inventories provided by customers and suppliers	$1.50	$1.90
Decline in Uranium Spot Price Indicator	19.00%	'
Decline in Uranium Quantities Provided by Customers and Suppliers	5.00%	'

Property_Plant_and_Equipment_P2

Property, Plant and Equipment Property, Plant and Equipment (Tables) (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Property, Plant and Equipment [Line Items]	'
Property, Plant and Equipment, Gross	$368.10
Property, Plant and Equipment, Additions	0
Property, Plant and Equipment, Transfers and Changes	-57.9
Property, Plant and Equipment, Disposals	-1.7
Property, Plant and Equipment, Gross	308.5
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	-317.1
Depreciation	-16.2
Accumulated Depreciation, Depletion and Amortization, Sale or Disposal of Property, Plant and Equipment	55.4
Other Depreciation and Amortization	-17.6
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	-295.5
Property, Plant and Equipment, Net	51
Property, Plant And Equipment, Net Capital Expenditures	-16.2
Accumulated Depreciation, Depletion and Amortization, Write-down of Property, Plant and Equipment	-2.5
Asset Retirement Charges	19.3
Property, Plant and Equipment, Net	13
Construction in Progress [Member]	'
Property, Plant and Equipment [Line Items]	'
Property, Plant and Equipment, Gross	2.7
Property, Plant and Equipment, Additions	0
Property, Plant and Equipment, Transfers and Changes	-0.6
Property, Plant and Equipment, Disposals	-1.7
Property, Plant and Equipment, Gross	0.4
Leasehold Improvements [Member]	'
Property, Plant and Equipment [Line Items]	'
Property, Plant and Equipment, Gross	183.7
Property, Plant and Equipment, Additions	0
Property, Plant and Equipment, Transfers and Changes	-42.3
Property, Plant and Equipment, Disposals	0
Property, Plant and Equipment, Gross	141.4
Machinery and Equipment [Member]	'
Property, Plant and Equipment [Line Items]	'
Property, Plant and Equipment, Gross	181.7
Property, Plant and Equipment, Additions	0
Property, Plant and Equipment, Transfers and Changes	-15
Property, Plant and Equipment, Disposals	0
Property, Plant and Equipment, Gross	$166.70

Property_Plant_and_Equipment_P3

Property, Plant and Equipment Property, Plant and Equipment (Narrative) (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Property, Plant and Equipment [Abstract]	'
Asset Retirement Charges	$19.30

Deferred_Revenue_and_Advances_2

Deferred Revenue and Advances from Customers (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Deferred Revenue and Credits, Current [Abstract]	'	'	'	'	'
Advances from customers	$0	'	$0	'	$2.40
Other (income)	$35.90	$34.60	$124.20	$44.60	'

Deferred_Revenue_and_Advances_3

Deferred Revenue and Advances from Customers (Deferred Revenue and Advances From Customers) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Deferred Revenue and Credits, Current [Abstract]	'	'
Deferred revenue	$163.70	$123.10
Advances from customers	0	2.4
Total	163.7	125.5
Deferred costs associated with deferred revenue	$136.60	$116.80

Debt_Narrative_Details

Debt (Narrative) (Details) (USD $)	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Credit facility term loan	$0	'	$83.20
Convertible senior notes	530	'	530
Line of Credit Facility, Maximum Borrowing Capacity	'	$110	'
Convertible Debt [Member]	'	'	'
Debt instrument interest rate	3.00%	'	'

Debt_Schedule_of_Revolving_Cre

Debt (Schedule of Revolving Credit Facility) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Line of Credit Facility [Abstract]	'	'
Credit facility term loan	$0	$83.20
Letters of credit outstanding, amount	1.6	14.7
Available credit	$0	$87.10

Debt_Schedule_of_Deferred_Fina

Debt (Schedule of Deferred Financing Costs) (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Bank credit facilities [Member]	'
Deferred Finance Costs, Beginning Balance	$3
Deferred financing costs, additions	2.1
Deferred financing costs, reductions	-5.1
Deferred Finance Costs, End Balance	0
Convertible notes [Member]	'
Deferred Finance Costs, Beginning Balance	3.6
Deferred financing costs, reductions	-1.5
Deferred Finance Costs, End Balance	$2.10

Fair_Value_Measurements_Financ

Fair Value Measurements (Financial Instruments Recorded at Fair Value) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Cash equivalents	$127.90	$292.20
Deferred compensation asset	3	2.7
Deferred compensation obligation	2.8	2.7
Level 2 [Member]	'	'
Cash equivalents	127.9	292.2
Deferred compensation asset	3	2.7
Deferred compensation obligation	$2.80	$2.70

Fair_Value_Measurements_Debt_D

Fair Value Measurements (Debt) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Fair Value Disclosures [Abstract]	'	'
Credit facility term loan	$0	$83.20
Credit facility term loan, fair value	'	93.5
Convertible preferred stock	110.4	100.5
Convertible preferred stock, fair value	110.4	100.5
Convertible senior notes	530	530
Convertible senior notes, fair value	$140.50	$198.20

Fair_Value_Measurements_Narrat

Fair Value Measurements (Narrative) (Details) (USD $)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Preferred stock dividend rate	12.75%
Liquidation value, per share	$1,000

Pension_and_Postretirement_Hea2

Pension and Postretirement Health and Life Benefits (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Curtailment (gains)	$0.70	'	'	'	'
Decrease in pension liability, curtailments	138.3	'	'	'	'
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.92%	'	4.92%	'	4.07%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	4.00%	'	4.00%	'	4.00%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets	6.75%	'	'	'	6.75%
Net defined benefit plan costs for former Portsmouth employees	'	3.3	7.5	9.9	'
Defined Contribution Plan, Employer Matching Contribution, Percent	7.00%	'	4.00%	'	'
Defined Benefit Pension Plans [Member]	'	'	'	'	'
Expected defined benefit plan contributions for current fiscal year	'	'	24.1	'	'
Expected defined benefit plan contributions for current fiscal year under ERISA	20.9	'	20.9	'	'
Expected defined benefit plan contributions for current fiscal year for non-qualified plans	2.5	'	2.5	'	'
USEC contributions	'	'	16.2	'	'
Curtailment (gains)	$0	'	$0.70	'	'

Pension_and_Postretirement_Hea3

Pension and Postretirement Health and Life Benefits (Schedule of Net Benefit Costs) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Curtailment (gains)	($0.70)	'	'	'
Defined Benefit Pension Plans [Member]	'	'	'	'
Service costs	1.4	3.6	8.8	10.9
Interest costs	11.5	12.1	33.5	36.2
Expected return on plan assets (gains)	-12.8	-12.9	-38.3	-38.9
Amortization of prior service costs	0	0.3	0.7	1.1
Amortization of actuarial (gains) losses, net	2	5	14.2	14.8
Curtailment (gains)	0	'	-0.7	'
Net benefit costs	2.1	8.1	18.2	24.1
Postretirement Health and Life Benefits Plans [Member]	'	'	'	'
Service costs	0.9	0.9	2.7	2.7
Interest costs	2.2	2.7	6.7	8.3
Expected return on plan assets (gains)	-0.5	-0.7	-1.7	-2.1
Amortization of actuarial (gains) losses, net	0.6	1.2	2	3.4
Net benefit costs	$3.20	$4.10	$9.70	$12.30

StockBased_Compensation_Narrat

Stock-Based Compensation (Narrative) (Details) (USD $)	9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013
Share-based Compensation [Abstract]	'
Unrecognized compensation cost	$1.10
Weighted-average period in years of costs to be recognized	'1 year 2 months 12 days
Surrender and cancellation of unexercised stock options	2,462,726

StockBased_Compensation_StockB

Stock-Based Compensation (Stock-Based Compensation Costs) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Share-based Compensation [Abstract]	'	'	'	'
Restricted stock and restricted stock units	$0.30	$0.70	$1.60	$3.20
Stock options, performance awards and other	0	0.1	0.1	0.6
Less: costs capitalized as part of inventory	'	0	'	-0.1
Expense included in selling, general and administrative and advanced technology costs	$0.30	$0.80	$1.70	$3.70

Income_Taxes_Details

Income Taxes (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Interim temporary timing difference in income tax calculation	$14.90

Net_Income_Per_Share_Narrative

Net Income Per Share (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Debt Instrument [Line Items]	'	'	'	'
Interest expense	$9.50	$12.30	$32.10	$37.70
Maximum percentage of common stock shares for preferred stock conversion	19.99%	'	19.99%	'
Maximum number of common stock shares for preferred stock conversion	0.9	'	0.9	'
Convertible Debt [Member]	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'
Interest expense	$5.10	$4.90	$15.20	$14.40

Net_Income_Per_Share_Schedule_

Net Income Per Share (Schedule of Income Per Share) (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Earnings Per Share [Abstract]	'	'	'	'	'	'
Net (loss) from continuing operations	($44.30)	$5	($108.90)	($116.40)	'	'
Net income (loss) from discontinued operations	0	-0.5	21.7	0.1	'	'
Net income (loss)	-44.3	4.5	-87.2	-116.3	1,200	491.1
Net (loss) from continuing operations - if converted	-44.3	5	-108.9	-116.4	'	'
Net income from discontinued operations - if converted	0	-0.5	21.7	0.1	'	'
Net (loss) - if converted	($44.30)	$4.50	($87.20)	($116.30)	'	'
Weighted average common shares	5	5	5	5	'	'
Less: Weighted average unvested restricted stock	0.1	0.1	0.1	0.1	'	'
Denominator for basic calculation	4.9	4.9	4.9	4.9	'	'
Convertible notes	1.8	1.8	1.8	1.8	'	'
Convertible preferred stock - equivalent common shares	13.7	4.3	10.5	3.5	'	'
Convertible preferred stock - less: share issuance limitation	12.8	3.4	9.6	2.6	'	'
Convertible preferred stock - net allowable shares	0.9	0.9	0.9	0.9	'	'
Subtotal	2.7	2.7	2.7	2.7	'	'
Less: shares excluded in a period of net loss or antidilution	2.7	2.7	2.7	2.7	'	'
Denominator for diluted calculation	4.9	4.9	4.9	4.9	'	'
Net income (loss) from continuing operations per share – basic and diluted	($9.04)	$1.02	($22.22)	($23.75)	'	'
Net income per share from discontinued operations - basic and diluted	$0	($0.10)	$4.43	$0.02	'	'
Net income (loss) per share – basic and diluted	($9.04)	$0.92	($17.79)	($23.73)	'	'

Net_Income_Per_Share_Net_Incom

Net Income Per Share Net Income Per Share (Schedule of Securities Excluded from Net Income Per Share) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Options excluded from diluted net income per share	1,000	111,000	1,000	111,000
Warrants excluded from diluted net income per share	250,000	250,000	250,000	250,000
Exercise price of excluded warrants	$187.50	$187.50	$187.50	$187.50
Minimum [Member]	'	'	'	'
Exercise price of excluded options	$177.50	$93	$177.50	$93
Maximum [Member]	'	'	'	'
Exercise price of excluded options	$357	$357	$357	$357

Commitment_and_Contingencies_D

Commitment and Contingencies (Details) (USD $)	19 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
Commitments and Contingencies Disclosure [Abstract]	'	'	'	'	'
Maximum funding for RD&D Program - Revised Estimate	$320,000,000	'	'	'	'
RD&D Program Funding by DOE	80.00%	'	'	'	'
RD&D Program Funding by USEC	20.00%	'	'	'	'
RD&D Program Funding by DOE To Date	241,300,000	'	'	'	'
RD&D Program Funding by DOE - Increment 5	13,600,000	'	'	'	'
Amount of application under DOE Loan Guarantee Program	'	2,000,000,000	'	'	'
Potential financing from Japanese export credit agencies under discussion	'	1,000,000,000	'	'	'
Minimum additional financing needed for ACP beyond DOE and Japanese	'	1,000,000,000	'	'	'
NYSE 30-day average minimum market capitalization	'	50,000,000	'	'	'
NYSE Minimum 30 Day Average Closing Price	'	$1	'	'	'
NYSE 30-Day Market Capitalization Subject to Suspension	'	15,000,000	'	'	'
Stockholders’ Equity (Deficit)	'	-462,100,000	-472,900,000	652,200,000	752,400,000
PBGC estimate of potential Portsmouth pension liability	'	130,000,000	'	'	'
Long-Term Debt	'	$530,000,000	$530,000,000	'	'
Minimum Paducah SWU Production Under 2002 DOE-USEC Agreement	'	3,500,000	'	'	'

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Loss) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'	'	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	($196.50)	($254.30)	($291.90)	($262.50)
Gain arising during the period	0	0	138.3	0
Amortization of actuarial (gains) losses, net (Note 11)	2.6	6.2	15.5	18.2
Amortization of prior service costs (Note 11)	0	-0.3	-0.7	-1.1
Total reclassifications for the period, before tax	2.6	6.5	154.5	19.3
Income tax expense related to items of other comprehensive income	-1.5	-2.4	-58	-7
Other comprehensive income, net of tax	1.1	4.1	96.5	12.3
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	($195.40)	($250.20)	($195.40)	($250.20)

Segment_Information_Segment_Re

Segment Information (Segment Reporting Information) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues [Abstract]	'	'	'	'
Separative work units	$295.80	$559.50	$853.40	$1,444.60
Uranium	3.8	0	45.3	3.6
Revenue from low enriched uranium segment	299.6	559.5	898.7	1,448.20
Contract services	4.2	3.5	10.3	10.6
Total Revenue	303.8	563	909	1,458.80
LEU segment gross profit	-30.8	36.7	-63.7	83.8
Contract services segment gross profit	0.8	-0.1	0.1	-0.3
Gross profit	($30)	$36.60	($63.60)	$83.50