Centrus Energy (LEU) 10-K 31 Mar 17 2016 Q4 Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Mar. 28, 2017	Jun. 30, 2016
Document and Entity Information
Entity Registrant Name	CENTRUS ENERGY CORP
Entity Central Index Key	1,065,059
Trading Symbol	LEU
Current Fiscal Year End Date	--12-31
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		9,000,000
Document Fiscal Year Focus	2,016
Entity Well-known Seasoned Issuer	No
Entity Public Float			$ 17,000,000
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Document Fiscal Period Focus	Q4

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Current Assets
Cash and cash equivalents	$ 260.7	$ 234
Accounts receivable, net	19.9	26.5
Inventories	177.4	319.2
Deferred costs associated with deferred revenue	89.3	63.1
Other current assets	13.3	15.2
Total current assets	560.6	658
Property, Plant and Equipment, Net	6	3.5
Deposits for surety bonds	29.5	29.8
Intangible assets	93.3	105.8
Other long-term assets	24.1	23
Total Assets	713.5	820.1
Current Liabilities
Accounts payable and accrued liabilities	46.4	44.8
Payables under SWU purchase agreements	59.6	85.4
Inventories owed to customers and suppliers	57.5	106.8
Deferred revenue	123.6	83.9
Decontamination and decommissioning obligations	38.6	29.4
Total current liabilities	325.7	350.3
Long-term debt	234.1	247
Postretirement health and life benefit obligations	171.3	184.3
Pension benefit liabilities	179.9	172.3
Other long-term liabilities	38.6	31.9
Total liabilities	949.6	985.8
Commitments and contingencies (Note 16)
Stockholders' Equity (Deficit)
Additional Paid in Capital	59.5	59
Retained Earnings (Accumulated Deficit)	(296.7)	(229.7)
Accumulated Other Comprehensive Income (Loss), Net of Tax	0.2	4.1
Total stockholders’ equity (deficit)	(236.1)	(165.7)
Total Liabilities and Stockholders’ Equity (Deficit)	713.5	820.1
Common Class A [Member]
Stockholders' Equity (Deficit)
Common Stock, Value, Issued	0.8	0.8
Common Class B [Member]
Stockholders' Equity (Deficit)
Common Stock, Value, Issued	$ 0.1	$ 0.1

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parentheticals) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Preferred Stock, Par Value Per Share	$ 1	$ 1
Preferred Stock, Shares Authorized	20,000,000	20,000,000
Common Stock, Shares, Issued	9,000,000
Common Class A [Member]
Common Stock, Par or Stated Value Per Share	$ 0.10	$ 0.10
Common Stock, Shares Authorized	70,000,000	70,000,000
Common Stock, Shares, Issued	7,563,600	7,563,600
Common Class B [Member]
Common Stock, Par or Stated Value Per Share	$ 0.10	$ 0.10
Common Stock, Shares Authorized	30,000,000	30,000,000
Common Stock, Shares, Issued	1,436,400	1,436,400

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Revenue:
Total Revenue	$ 311.3	$ 418.2
Cost of Sales:
Separative work units and uranium	234.3	285.3
Contract services	31.9	64
Total cost of sales	266.2	349.3
Gross profit (loss)	45.1	68.9
Advanced technology costs	47.9	33
Selling, general and administrative	46.2	42.6
Amortization of intangible assets	12.5	13.4
Impairment of excess reorganization value	0	137.2
Special charges for workforce reductions	1.4	13.2
Gains on sales of assets	(1.2)	(2.1)
Operating (loss)	(61.7)	(168.4)
Gain on early extinguishment of debt and debt restructuring costs	(13)
Interest expense	19.7	19.6
Investment income	(0.8)	(0.3)
Loss before income taxes	(67.6)	(187.7)
Provision (benefit) for income taxes	(0.6)	(0.3)
Net loss	$ (67)	$ (187.4)
Net loss per share - basic and diluted	$ (7.36)	$ (20.82)
Weighted-average number of shares outstanding:
Weighted Average Number of Shares Outstanding, Basic and Diluted	9.1	9

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Net loss	$ (67)	$ (187.4)
Prior service credit arising during the period	(3.6)	0
Amortization of prior service costs (credits)	(0.3)	(0.3)
Other comprehensive income (loss), before tax	(3.9)	(0.3)
Income tax expense related to items of other comprehensive income	0	0
Other comprehensive income (loss), net of tax	(3.9)	(0.3)
Comprehensive income (loss)	$ (70.9)	$ (187.7)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities
Net loss	$ (67)	$ (187.4)
Adjustments to reconcile net income (loss) to net cash (used in) operating activities:
Depreciation and amortization	13.1	13.8
Impairment of excess reorganization value	0	137.2
Immediate recognition of net actuarial losses	1.4	(29.6)
Interest on paid-in-kind toggle notes	9.7	5.4
Gain on early extinguishment of debt and debt restructuring costs	(16.7)	0
Gain on sale of assets	(1.2)	(2.1)
Non-cash reorganization items	3	0
Changes in operating assets and liabilities:
Accounts receivable – (increase) decrease	6.5	29.3
Inventories, net – (increase) decrease	89.5	90.9
Payables under SWU purchase agreements – increase (decrease)	(25.8)	(54.7)
Deferred revenue, net of deferred costs – increase (decrease)	13.4	2.6
Accounts payable and other liabilities – (decrease)	10.4	(1.8)
Other, net	1.4	4.9
Net Cash (Used in) Operating Activities	37.7	8.5
Cash Flows Provided by Investing Activities
Capital expenditures	(3)	(0.3)
Proceeds from sales of assets	1.5	2
Deposits for surety bonds - net (increase) decrease	0.3	5
Net Cash Provided by Investing Activities	(1.2)	6.7
Cash Flows Used in Financing Activities
Common stock issued (purchased), net	9.8	0
Net Cash (Used in) Financing Activities	(9.8)	0
Net (Decrease)	26.7	15.2
Cash and Cash Equivalents at Beginning of Period	234	218.8
Cash and Cash Equivalents at End of Period	260.7	234
Supplemental Cash Flow Information:
Interest paid	6.5	12.2
Income taxes paid	0	0.3
Conversion of interest payable-in-kind to long-term debt	$ 3.4	$ 1.8

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	Common Stock Par Value $.10 per Share [Member]Common Class A [Member]	Common Stock Par Value $.10 per Share [Member]Common Class B [Member]	Excess of Capital over Par Value [Member]	Retained Earnings (Deficit) [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance at Dec. 31, 2014	$ 21.6	$ 0.8	$ 0.1	$ 58.6	$ (42.3)	$ 4.4
Net loss	(187.4)
Other comprehensive income, net of tax (Note 14)	(0.3)					(0.3)
Restricted and other common stock issued, net of amortization	0.4			0.4
Ending Balance at Dec. 31, 2015	(165.7)	0.8	0.1	59	(229.7)	4.1
Net loss	(67)
Other comprehensive income, net of tax (Note 14)	(3.9)					(3.9)
Restricted and other common stock issued, net of amortization	0.5			0.5
Ending Balance at Dec. 31, 2016	$ (236.1)	$ 0.8	$ 0.1	$ 59.5	$ (296.7)	$ 0.2

Summary of Significant Accounti

Summary of Significant Accounting Policies (Notes)	12 Months Ended
	Dec. 31, 2016
Summary of Significant Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation and Principles of Consolidation The consolidated financial statements of Centrus Energy Corp. (“Centrus” or the “Company”) were prepared in conformity with generally accepted accounting principles in the U.S. (“U.S. GAAP”). Certain prior year amounts have been reclassified to conform to the current presentation. The consolidated financial statements include the accounts of Centrus, its principal subsidiary United States Enrichment Corporation (“Enrichment Corp.”), and its other subsidiaries. All material intercompany transactions are eliminated. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect reported amounts presented and disclosed in the consolidated financial statements. Significant estimates and judgments include, but are not limited to, asset valuations, American Centrifuge decontamination and decommissioning obligations, pension and postretirement health and life benefit costs and obligations, the tax bases of assets and liabilities, the future recoverability of deferred tax assets, and determination of the valuation allowance for deferred tax assets. Actual results may differ from such estimates, and estimates may change if the underlying conditions or assumptions change. Cash and Cash Equivalents Cash and cash equivalents include short-term or highly liquid assets with original maturities of three months or less. Inventories and Inventories Owed to Customers and Suppliers 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 U 235 and depleted uranium having a lower percentage of U 235 . 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 or “feed” component. SWU and uranium inventory costs are determined using the monthly moving average cost method. SWU and uranium purchase costs include shipping costs when applicable. Inventories of SWU and uranium are valued at the lower of cost or net realizable value (“NRV”). NRV is the estimated selling price in the ordinary course of business less reasonably predictable costs of completion, disposal, and transportation. The estimated selling price for SWU and uranium is based on the pricing terms of contracts in the Company’s sales order book, and, for uranium not under contract, the estimated selling price is based primarily on published price indicators at the balance sheet date. 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 Centrus and domestic fabricators, fabricators order quantities of LEU from Centrus based on scheduled or anticipated orders from utility customers for deliveries in future periods. As delivery obligations under actual customer orders arise, Centrus satisfies these obligations by arranging for the transfer to the customer of title to the specified quantity of LEU at the fabricator. Centrus’ balances of SWU and uranium vary over time based on the timing and size of the fabricator’s LEU orders from Centrus 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 Centrus than Centrus is required to deliver to its customers at the fabricator, the fabricator will use these other inventories to satisfy Centrus’ customer order obligations on Centrus’ behalf. In such cases, the transfer of title of LEU from Centrus to the customer results in quantities of SWU and uranium being owed by Centrus to the fabricator. The amounts of SWU and uranium owed to fabricators are satisfied as future deliveries of LEU to fabricators are made. Deferred Taxes Centrus follows the asset and liability approach to account for deferred taxes. Deferred tax assets and liabilities are recognized for the anticipated future tax consequences of temporary differences between the balance sheet carrying amounts of assets and liabilities and their respective tax bases. Deferred taxes are based on income tax rates in effect for the years in which temporary differences are expected to reverse. The effect on deferred taxes of a change in income tax rates is recognized in income when the change in rates is enacted in the law. A valuation allowance is provided if it is more likely than not that some or all of the deferred tax assets may not be realized. Property, Plant and Equipment Property, plant and equipment are recorded at acquisition cost. Leasehold improvements and machinery and equipment are depreciated on a straight line basis over the shorter of the useful life of the assets or the lease term, if applicable. Refer also to Carrying Value of Long-Lived Assets below. Intangible Assets Centrus has intangible assets resulting from fresh start accounting as a result of emergence from Chapter 11 bankruptcy on September 30, 2014. The identifiable intangible assets relate to the sales order book and customer relationships. The order book intangible asset is amortized as the order book valued at emergence is reduced, principally as result of deliveries to customers. The customer relationships intangible asset is amortized using the straight-line method over the estimated average useful life of 15 years. Refer also to Carrying Value of Long-Lived Assets below. The excess of the reorganization value over the fair value of identified tangible and intangible assets resulted in a nonamortizing intangible asset as of September 30, 2014. The excess reorganization value (or “goodwill”, as defined by the accounting standards) was tested for impairment and was determined to be fully impaired as of October 1, 2015. Therefore, the Company recorded an impairment charge in the fourth quarter of 2015. Carrying Value of Long-Lived Assets The carrying values of property, plant and equipment and identifiable intangible assets are subject to impairment tests whenever adverse conditions or changes in circumstances indicate a possible impairment loss. Impairment tests are based on a comparison of estimated future cash flows to the carrying value of long-lived assets. If impairment is indicated, the asset carrying value is reduced to its fair value and an impairment loss is recognized. Financial Instruments and Fair Value Measurement Accounting standards define fair value as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required or permitted to be recorded at fair value, consideration is given to the principal or most advantageous market and assumptions that market participants would use when pricing the asset or liability. Pursuant to accounting standards, Centrus’ paid-in-kind toggle notes are recorded at face value and the fair value is disclosed. The estimated fair value of the paid-in-kind toggle notes is based on the most recent trading price as of the balance sheet date. Debt issuance costs are deferred and amortized over the life of the instrument. The balance sheet carrying amounts for accounts receivable, accounts payable and accrued liabilities, and payables under SWU purchase agreements approximate fair value because of the short-term nature of the instruments. Concentrations of Credit Risk Credit risk could result from the possibility of a customer failing to perform or pay according to the terms of a contract. Extension of credit is based on an evaluation of each customer’s financial condition. Centrus regularly monitors credit risk exposure and takes steps to mitigate the likelihood of such exposure resulting in a loss. SWU and Uranium Revenue Revenue is derived from sales of the SWU component of LEU, from sales of both the SWU and uranium components of LEU, and from sales of uranium. Revenue is recognized at the time LEU or uranium is delivered under the terms of contracts with domestic and international electric utility customers. Most customers take title and delivery of LEU at fuel fabricators. Centrus ships LEU to nuclear fuel fabricators for scheduled or anticipated orders from utility customers. Based on customer orders, Centrus arranges for the transfer of title of LEU from Centrus to the customer for the specified quantity of LEU at the fuel fabricator. Revenue is recognized when delivery of LEU to the customer occurs at the fuel fabricator. In a limited number of sales transactions, title to uranium or LEU is transferred to the customer without Centrus physically delivering the uranium or LEU to the customer. In such cases, risk of loss remains with Centrus until physical delivery occurs. At the time transfer of title occurs, a performance obligation for Centrus is created and a receivable is recorded. Cash is collected for the receivable under normal credit terms. The recognition of revenue and related cost of sales occurs at the time physical delivery occurs and risk of loss transfers to the customer. On occasion, Centrus will accept payment in the form of uranium. Revenue from the sale of SWU under such contracts is recognized at the time LEU is delivered and is based on the fair value of the uranium received in exchange for the SWU. Contract Services Revenue The contract services segment consists primarily of revenue and cost of sales for engineering and testing work Centrus performs under an agreement with UT-Battelle, LLC (“UT-Battelle”), the management and operating contractor for Oak Ridge National Laboratory (“ORNL”). The contract services segment also includes limited services provided by Centrus to the U.S. Department of Energy (“DOE”) and its contractors at the Portsmouth site related to facilities the Company leases from DOE. Contract services revenue includes billings for fees and payments for allowable costs that are determined in accordance with the terms of the underlying contracts. The contract with UT-Battelle provides for fixed payments for monthly reports. Revenue is recognized as work is performed and as fees are earned. The Company’s spending levels for the UT-Battelle contract work are consistent with the fixed funding levels. The Company’s costs in support of receiving payment under the UT-Battelle contract consist of allowable costs under government cost accounting standards (“CAS”). Allowable costs include direct costs as well as allocations of indirect plant and corporate overhead costs determined in accordance with CAS. Allowable costs are subject to audit by the Defense Contract Audit Agency (“DCAA”), or such other entity that DOE authorizes to conduct the audit. Centrus and DOE have yet to fully settle the Company’s claims for reimbursements for allowable costs related to past contract work performed at the Portsmouth and Paducah sites. The final settlement is subject to Federal Acquisition Regulations requiring the DOE contracting officer to conduct negotiations and prepare a written indirect cost agreement. Revenue resulting from final billing rates is recognized upon completion of the government audits and notice by DOE authorizing final billing. DOE historically has not approved Centrus’ provisional billing rates and has not completed audits of Centrus’ incurred cost submissions and authorized final payments in a timely manner. Additional details are provided in Note 4, Receivables . There is the potential for additional revenue to be recognized, based on the outcome of DOE reviews and audits, as the result of the release of previously established receivable related reserves. However, since these periods have not been finalized with DOE, uncertainty exists and Centrus has not yet recognized this additional revenue. Advanced Technology License and Decommissioning Costs American Centrifuge expenses that are outside of our contracts with UT-Battelle are included in Advanced Technology License and Decommissioning Costs , including ongoing costs to maintain the demobilized Piketon facility and our licenses from the U.S. Nuclear Regulatory Commission (“NRC”) at that location. In the second quarter of 2016, the Company commenced with the decontamination and decommissioning (“D&D”) of the Piketon facility in accordance with the requirements of the NRC and DOE. Refer to Note 3, Contract Services and Advanced Technology License and Decommissioning Costs, and Note 16, Commitments and Contingencies, for further details regarding the American Centrifuge project. Pension and Postretirement Health and Life Benefit Plans The Company provides retirement benefits to certain employees and retirees under defined benefit pension plans and postretirement health and life benefit plans. The valuation of benefit obligations and costs is based on provisions of the plans and actuarial assumptions that involve judgments and estimates. Plan assets and benefit obligations are remeasured each year as of the balance sheet date, or when lump-sum payments exceed certain levels, resulting in differences between actual and projected results. The Company has elected to recognize these actuarial gains and losses immediately in the statement of operations to provide transparency regarding the impacts of changes in plan assets and benefit obligations. Stock-Based Compensation Centrus has a stock-based compensation plan which authorizes the issuance of common stock to the Company’s employees, officers, directors and other individuals providing services to the Company or its affiliates pursuant to options, stock appreciation rights, restricted stock units, restricted stock, performance awards, dividend equivalent rights and other stock based awards. Stock-based compensation cost is measured at the grant date based on the fair value of the award. The cost is recognized over the requisite service period on a straight-line basis over the vesting period. New Accounting Standards In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers (Topic 606) . ASU 2014-09 introduces a new five-step revenue recognition model in which an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also requires disclosures sufficient to enable users to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers, including qualitative and quantitative disclosures about contracts with customers, significant judgments and changes in judgments, and assets recognized from the costs to obtain or fulfill a contract. The FASB issued amendments in 2015 and 2016 that provide clarification on a number of specific issues as well as requiring additional disclosures. The revenue recognition standard will become effective for the Company beginning with the first quarter of 2018. The Company is evaluating the effect that the provisions of ASU 2014-09 will have on its consolidated financial statements. In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements - Going Concern (Subtopic 205-40) , which requires an evaluation of whether there is substantial doubt about a company’s ability to continue as a going concern and provide certain disclosures depending on the result of such evaluation. For each reporting period, management will be required to evaluate whether there are conditions or events that raise substantial doubt about a company’s ability to continue as a going concern within one year from the date the financial statements are issued. If management identifies such conditions or events, ASU 2014-15 requires disclosures in the notes to the financial statements that outline whether or not there are any plans intended to mitigate the relevant conditions or events to alleviate the substantial doubt. ASU 2014-15 was effective for the Company beginning in the fourth quarter of 2016. The adoption of ASU 2014-15 did not have a material impact on the Company’s consolidated financial statements. In April 2015, the FASB issued ASU 2015-03, Interest - Imputation of Interest (Subtopic 835-30), requiring the presentation of debt issuance costs in the balance sheet as a reduction in the carrying amount of the related debt liability instead of a deferred charge asset. Centrus adopted ASU 2015-03 with retrospective application beginning with the first quarter of 2016. The reclassification of debt issuance costs did not have a material impact on Centrus’ consolidated financial statements. Refer to Note 9, Debt , for details. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842), which requires lessees to recognize a right-of-use asset and lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting expense recognition in the statement of operations. ASU 2016-02 is effective for the Company in the first quarter of 2019, with early adoption permitted, and is to be applied using a modified retrospective approach. The Company is evaluating the effect that the provisions of ASU 2016-02 will have on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, Stock Compensation - Improvements to Employee Share-Based Payment Accounting (Topic 718) . ASU 2016-09 simplifies several aspects of the accounting for share-based payment transactions, including income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. ASU 2016-09 is effective for the Company beginning in the first quarter of 2017. Under ASU 2016-09, entities are permitted to make an accounting policy election to either estimate forfeitures on share-based payment awards, as previously required, or to recognize forfeitures as they occur. The Company has elected to recognize forfeitures as they occur. The provisions of ASU 2016-09 are not expected to have a material impact on the Company’s consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments . ASU 2016-15 addresses the presentation and classification of certain cash receipts and cash payments in the statement of cash flows. It is intended to reduce diversity in practice by providing guidance on eight specific cash flow issues. ASU 2016-15 is effective for the Company beginning in the first quarter of 2018, with early adoption permitted, and is to be applied using a retrospective approach. The provisions of ASU 2016-15 are not expected to have a material impact on the Company’s consolidated financial statements. In October 2016, the FASB issued ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory, requiring an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. ASU 2016-09 is effective for the Company beginning in the first quarter of 2018. Early adoption is permitted. The provisions of ASU 2016-16 are not expected to have a material impact on the Company’s consolidated financial statements. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash . ASU 2016-18 requires that the statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. ASU 2016-18 is to be applied retrospectively for each period presented, and is effective for the Company beginning in the first quarter of 2018. Early adoption is permitted. The provisions of ASU 2016-18 are not expected to have a material impact on the Company’s consolidated financial statements.

Special Charges

Special Charges	12 Months Ended
	Dec. 31, 2016
Restructuring and Related Activities [Abstract]
Special Charges	SPECIAL CHARGES Enrichment Cessation and Evolving Business Needs The cessation of enrichment at the Paducah Gaseous Diffusion Plant (the “Paducah GDP”) and evolving business needs have resulted in workforce reductions since July 2013. Special charges include related termination benefits less severance paid by the Company and invoiced to the U.S. Department of Energy (“DOE”) for its share of employee severance pursuant to the USEC Privatization Act. In the second quarter of 2016, the Company commenced a project to align its corporate structure to the scale of its ongoing business operations and to update related information technology. The Company has incurred advisory costs related to the reengineering project of $1.0 million in 2016. In addition, special charges in 2016 included termination benefits of $0.3 million related to voluntary workforce reductions. Piketon Demonstration Facility In September 2015, Centrus completed a successful three-year demonstration of American Centrifuge technology at its facility in Piketon, Ohio, with 120 machines linked together in a cascade to simulate industrial operating conditions. The demonstration effort was primarily funded by the U.S. government. As a result of reduced program funding, Centrus incurred a special charge of $8.7 million in the third quarter of 2015 for estimated employee termination benefits, consisting primarily of payments under its pre-existing severance plan. An additional $0.1 million special charge was incurred in the second quarter of 2016 as an adjustment to accrued severance benefits for current salary levels. A summary of termination benefit activity and related liabilities follows (in millions): Liability Dec. 31, 2014 2015 Liability Dec. 31, 2015 2016 Liability Dec. 31, 2016 Special Charges Paid Special Charges Paid Workforce reductions: Enrichment cessation and evolving business needs $ 2.4 $ 4.5 (a) $ (6.6 ) (a) $ 0.3 $ 0.3 $ (0.5 ) $ 0.1 Piketon demonstration facility — 8.7 (0.3 ) 8.4 0.1 (3.1 ) 5.4 (b) $ 2.4 $ 13.2 $ (6.9 ) $ 8.7 $ 0.4 $ (3.6 ) $ 5.5 (a) Net of $0.4 million billed to and paid by DOE. (b) Includes $2.1 million included in long-term liabilities.

Contract Services and Advanced

Contract Services and Advanced Technology License and Decommissioning Costs	12 Months Ended
	Dec. 31, 2016
Research and Development [Abstract]
Contract Services and Advanced Technology License and Decommissioning Costs	CONTRACT SERVICES AND ADVANCED TECHNOLOGY LICENSE AND DECOMMISSIONING COSTS The contract services segment includes Revenue and Cost of Sales for engineering and testing work Centrus performs on the American Centrifuge technology under government contract with UT-Battelle. Centrus entered into a new contract with UT-Battelle on September 19, 2016, valued at approximately $25 million for the period from October 1, 2016, through September 30, 2017 (the “2017 ORNL Contract”). The 2017 ORNL Contract provides for payments for monthly reports of approximately $2.0 million per month and additional aggregate payments of $1.0 million based on completion of certain milestones. The 2017 ORNL Contract is currently being funded incrementally. Funding for the program is provided to UT-Battelle by the federal government which is currently operating under a continuing resolution. The Company’s contract with UT-Battelle that ended September 30, 2016 (the “2016 ORNL Contract”), provided for payments for monthly reports of approximately $2.7 million per month. The amount of funding under the 2016 ORNL Contract decreased from approximately $6.9 million per month received under contract for the government fiscal year that ended September 30, 2015 (the “2015 ORNL Contract”). Although the 2015 ORNL Contract expired September 30, 2015, Centrus continued to perform work at the expected reduced scope as the parties worked toward a successor agreement. The 2016 ORNL Contract, which was signed in March 2016, provided for payment for reports related to work performed since October 1, 2015. Revenue in 2016 includes $8.1 million for March 2016 reports on work performed in the three months ended December 31, 2015, and $30.4 million for reports on work performed in the year ended December 31, 2016. Expenses for contract work performed in the year ended December 31, 2016, are included in Cost of Sales . Expenses for work performed in the three months ended December 31, 2015, before entering into the 2016 ORNL Contract, were included in Advanced Technology License and Decommissioning Costs in 2015. American Centrifuge expenses that are outside of the Company’s contracts with UT-Battelle are included in Advanced Technology License and Decommissioning Costs, including ongoing costs to maintain the demobilized Piketon facility and our NRC licenses at that location. In the second quarter of 2016, the Company commenced with the D&D of the Piketon facility in accordance with the requirements of the NRC and DOE. Charges to Advanced Technology License and Decommissioning Costs included approximately $19 million in 2016 and approximately $7 million in 2015 to increase the accrued D&D liability based on updated cost estimates that reflect changes in the approach and anticipated timeframe over which the work will be conducted. As of December 31, 2016, the Company has accrued $38.6 million on the balance sheet as Decontamination and Decommissioning Obligations for the estimated fair value of the remaining costs to complete the D&D work. Refer to Note 16, Commitments and Contingencies , for additional details.

Accounts Receivable

Accounts Receivable	12 Months Ended
	Dec. 31, 2016
Accounts Receivable, Net, Current [Abstract]
Accounts Receivable	RECEIVABLES December 31, 2016 2015 (millions) Utility customers and other $ 15.3 $ 24.7 Contract services, primarily DOE 4.6 1.8 Accounts receivable, net $ 19.9 $ 26.5 Certain overdue receivables from DOE are included in other long-term assets based on the extended timeframe expected to resolve claims for payment. Unpaid invoices to DOE related to filed claims totaled approximately $78 million as of December 31, 2016, and December 31, 2015. Due to the lack of a resolution with DOE and uncertainty regarding the timing and amount of future collections, the long-term receivable for accounting purposes is $22.8 million as of December 31, 2016, and $23.0 million as of December 31, 2015, including updated submissions for final indirect rates and incurred costs, as well as invoices for interest. Centrus believes that DOE has failed to establish appropriate provisional billing and final indirect cost rates on a timely basis and the Company has filed claims with DOE for payment under the Contract Disputes Act (“CDA”). DOE denied the Company’s claims for payment of $38.0 million for the periods through 2011, and on May 30, 2013, the Company appealed DOE’s denial of its claims to the U.S. Court of Federal Claims. The Company has been able to reach a resolution on a portion of the amounts claimed, and DOE has now paid approximately $6.7 million of claims for work performed in 2003 through 2007. The Court dismissed claims against DOE related to approximately $3.8 million due from prime subcontractors to DOE. The Company is pursuing payment of such claims directly from DOE subcontractors, of which $0.4 million has been received. On October 5, 2015, the Company filed a motion for summary judgment on three issues which would be dispositive on most of the amounts claimed by the Company in the litigation. The briefing on the motion for summary judgment is complete. The parties are engaged in settlement discussions and further action on the case is stayed pending the outcome of such discussions. In December 2012, the Company invoiced DOE for $42.8 million , representing its share of pension and postretirement benefits costs related to the transition of Portsmouth site employees to DOE’s D&D contractor, as permitted by CAS and based on CAS calculation methodology. DOE denied payment on this invoice in January 2013, and subsequent to providing additional information, as requested, to DOE, the Company submitted a claim on August 30, 2013, under the CDA for payment of the $42.8 million. On August 27, 2014, the DOE contracting officer denied the Company’s claim. As a result, Centrus filed a complaint with the U.S. Court of Federal Claims in January 2015, but there is no assurance the Company will be successful in its appeal. The parties are engaged in settlement discussions and further action on the case is stayed pending the outcome of such discussions. The Company has a full valuation allowance for this claim due to the lack of a resolution with DOE and uncertainty regarding the amounts owed and the timing of collection. The amounts owed by DOE may be more than the amounts the Company has invoiced to date. Centrus has unapplied payments from DOE that may be used, at DOE’s direction, (a) to pay for future services provided by the Company or (b) to reduce outstanding receivables balances due from DOE. A payments balance of $19.3 million as of December 31, 2016, and $19.4 million as of December 31, 2015, is included in other long-term liabilities pending resolution of the long-term receivables from DOE described above.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2016
Inventory, Net [Abstract]
Inventories	INVENTORIES Centrus holds natural uranium and the uranium and SWU components of LEU at licensed locations. Components of inventories follow (in millions): December 31, 2016 December 31, 2015 Current Assets Current Liabilities (a) Inventories, Net Current Assets Current Liabilities (a) Inventories, Net Separative work units $ 115.8 $ 15.2 $ 100.6 $ 221.5 $ 33.1 $ 188.4 Uranium 61.4 42.3 19.1 97.5 73.7 23.8 Materials and supplies 0.2 — 0.2 0.2 — 0.2 $ 177.4 $ 57.5 $ 119.9 $ 319.2 $ 106.8 $ 212.4 (a) Inventories owed to customers and suppliers, included in current liabilities, consist primarily of SWU and uranium inventories owed to fabricators that process LEU into fuel for use in nuclear reactors. In 2015, Centrus exchanged SWU for uranium under a barter contract. SWU revenue of $8.3 million was recognized based on the fair market value of the uranium acquired in exchange for SWU delivered.

Property, Plant and Equipment P

Property, Plant and Equipment Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENT A summary of changes in property, plant and equipment follows (in millions): December 31, Additions / (Depreciation) Retirements December 31, Land $ 1.2 $ — $ — $ 1.2 Leasehold improvements 0.9 2.3 (0.2 ) 3.0 Machinery and equipment 1.6 0.1 — 1.7 Other 0.3 0.6 — 0.9 Property, plant and equipment, gross 4.0 3.0 (0.2 ) 6.8 Accumulated depreciation (0.5 ) (0.5 ) 0.2 (0.8 ) Property, plant and equipment, net $ 3.5 $ 2.5 $ — $ 6.0 Additions to property, plant and equipment in the year ended December 31, 2016, include leasehold improvements of $1.7 million that were funded by the owner of the Company’s corporate headquarters. Corresponding deferred rent credits are included in long-term liabilities and are being amortized as a reduction to rent expense over the lease term.

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	INTANGIBLE ASSETS Intangible assets originated from the Company’s reorganization and application of fresh start accounting as of September 30, 2014. The intangible assets represented the fair value adjustment to the assets and liabilities for the Company’s LEU segment. Identifiable Intangible Assets The identifiable intangible assets relate to the sales order book and customer relationships. The order book intangible asset is amortized as the order book valued at emergence is reduced, principally as a result of deliveries to customers. The customer relationships intangible asset is amortized using the straight-line method over the estimated average useful life of 15 years. Amortization expense is presented below gross profit on the consolidated statement of operations. Identifiable intangible assets consist of the following (in millions): December 31, 2016 December 31, 2015 Gross Carrying Amount Accumulated Amortization Net Amount Gross Carrying Amount Accumulated Amortization Net Amount Sales order book $ 54.6 $ 19.9 $ 34.7 $ 54.6 $ 12.0 $ 42.6 Customer relationships 68.9 10.3 58.6 68.9 5.7 63.2 $ 123.5 $ 30.2 $ 93.3 $ 123.5 $ 17.7 $ 105.8 The amount of amortization expense for intangible assets in each of the succeeding years is estimated to be as follows (in millions): 2017 $ 10.6 2018 8.9 2019 8.6 2020 9.7 2021 8.6 Thereafter 46.9 $ 93.3 Excess Reorganization Value The excess of the reorganization value over the fair value of identified tangible and intangible assets resulted in a nonamortizing intangible asset of $137.2 million as of September 30, 2014. The excess reorganization value (or “goodwill”, as defined by the accounting standards) was tested for impairment and was determined to be fully impaired as of October 1, 2015. Therefore, the Company recorded an impairment charge of $137.2 million in the fourth quarter of 2015. The Company tested the carrying amount of the excess reorganization value for impairment using the two-step quantitative approach outlined in Accounting Standards Codification Topic 350, Intangibles - Goodwill and Other . The reporting unit for purposes of assigning and assessing the excess reorganization value is the Company’s LEU operations. In the first step of the analysis, the Company compared the estimated fair value of the reporting unit to its carrying value, including the excess reorganization value. The fair value of the reporting unit was estimated using an income approach and a market approach. Under the market approach, the excess reorganization value was tested for impairment against the fair value of the Company since the Company’s LEU operations comprise substantially all of the Company’s assets and liabilities and is the Company’s principal source of revenue. The carrying value of total invested capital exceeded the fair value of the Company’s PIK Toggle Notes and the Common Stock (plus an estimated premium for theoretically controlling all shares). The trading prices of the PIK Toggle Notes and the Common Stock are observable inputs and, as such, indicate a level of independent, objective evidence in the fair value hierarchy (i.e., level one inputs) established in the accounting guidance. Because of the results of the market approach, the Company performed the second step of the impairment analysis in order to determine the implied fair value of the reporting unit’s excess reorganization value. The implied fair value of the excess reorganization value represents the excess of fair value of the reporting unit over the fair value amounts assigned to all of the assets and liabilities of the reporting unit as if it were to be acquired in a business combination and the current fair value of the reporting unit (as calculated in the first step) was the purchase price. Any amount remaining after this allocation represents the implied fair value of the excess reorganization value. The implied fair value of the reporting unit’s excess reorganization value is then compared to the carrying value of the excess reorganization value and any excess of carrying value over the implied fair value represents a non-cash impairment charge.

Accounts Payable and Accrued Li

Accounts Payable and Accrued Liabilities (Notes)	12 Months Ended
	Dec. 31, 2016
Accounts Payable and Accrued Liabilities [Abstract]
Accounts Payable and Accrued Liabilities [Text Block]	ACCOUNTS PAYABLE AND ACCRUED LIABILITIES December 31, ($ millions) 2016 2015 Trade payables $ 11.5 $ 5.4 Compensation and employee benefits 12.5 19.2 Postretirement health and life benefit obligations - current 13.8 5.3 Severance 3.4 8.7 Other accrued liabilities 5.2 6.2 $ 46.4 $ 44.8

Debt

Debt	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Debt	DEBT A summary of long-term debt follows (in millions): 8% Paid-in-Kind Toggle Notes Deferred Issuance Costs Total Long-Term Debt December 31, 2014 $ 240.4 $ (0.7 ) $ 239.7 PIK Interest 7.2 — 7.2 Amortization — 0.1 0.1 December 31, 2015 $ 247.6 $ (0.6 ) $ 247.0 PIK Interest 13.1 — 13.1 Repurchases (26.1 ) — (26.1 ) Amortization/Repurchases — 0.1 0.1 December 31, 2016 $ 234.6 $ (0.5 ) $ 234.1 On February 14, 2017, pursuant to an exchange offer and consent solicitation, Centrus exchanged $204.9 million of PIK Toggle Notes for $74.3 million of 8.25% notes due 2027 (the “8.25% Notes”), 104,574 shares of Series B Preferred Stock with liquidation preference of $1,000 per share, and $27.6 million of cash, leaving $29.6 million of PIK Toggle Notes remaining outstanding. Refer to Note 19, Subsequent Event. In June 2016, Centrus repurchased some of the Company’s 8.0% paid-in-kind (“PIK”) toggle notes (the “PIK Toggle Notes”) pursuant to a pre-arranged trading plan. The Company made cash payments of $9.8 million for PIK Toggle Notes having an aggregate principal balance of $26.1 million and accrued interest payable balance of $0.5 million. The gain on the early extinguishment of the PIK Toggle Notes was $16.7 million , net of commissions and unamortized deferred issuance costs totaling $0.1 million . The pre-arranged trading plan was adopted in accordance with guidelines specified under Rule 10b5-1 of the Securities Exchange Act of 1934 (the “10b5-1 Plan”). The 10b5-1 Plan provided that an independent broker selected by the Company repurchase PIK Toggle Notes on the open market within specified guidelines on the Company’s behalf. All repurchases were subject to SEC regulations as well as such other terms and conditions as specified in the 10b5-1 Plan. On July 11, 2016, the Company terminated the 10b5-1 Plan and subsequently cancelled the PIK Toggle Notes that were repurchased. The PIK Toggle Notes pay interest at a rate of 8.0% per annum. Interest is payable semi-annually in arrears based on a 360-day year consisting of twelve 30-day months. The principal amount is increased by any payment of interest in the form of PIK payments. The Company has the option to pay up to 5.5% per annum of interest due on the PIK Toggle Notes in the form of PIK payments. In 2015, the PIK option was up to 3.0% per annum. For payments in 2016 and through the semi-annual interest period ending March 31, 2017, the Company has elected to pay interest in the form of PIK payments at 5.5% per annum. Interest payable as of December 31, 2016, is $4.7 million , of which the cash portion of $1.5 million is included in accounts payable and accrued liabilities and the PIK portion of $3.2 million is included in other long-term liabilities. Issuance costs for the PIK Toggle Notes were deferred and are being amortized on a straight-line basis, which approximates the effective interest method, over the life of the PIK Toggle Notes. The PIK Toggle Notes will mature on September 30, 2019. However, the maturity date can be extended to September 30, 2024, upon the satisfaction of certain funding conditions described in the Indenture relating to the funding, under binding agreements, of (i) the American Centrifuge project or (ii) the implementation and deployment of a National Security Train Program utilizing American Centrifuge technology. The PIK Toggle Notes rank equally in right of payment with all existing and future unsubordinated indebtedness of the Company (other than the Issuer Senior Debt as defined below) and are senior in right of payment to all existing and future subordinated indebtedness of the Company. The PIK Toggle Notes are subordinated in right of payment to certain indebtedness and obligations of the Company described in the Indenture (the “Issuer Senior Debt”), including (i) any indebtedness of the Company under a future credit facility, (ii) obligations of, and claims against, the Company under any equity investment (or any commitment to make an equity investment) with respect to the financing of the American Centrifuge project, (iii) obligations of, and claims against, the Company under any arrangement with DOE, export credit agencies or any other lenders or insurers with respect to the financing or government support of the American Centrifuge project and (iv) indebtedness of the Company to Enrichment Corp. under the Centrus Intercompany Note. The PIK Toggle Notes are guaranteed and secured on a subordinated, conditional, and limited basis by Enrichment Corp. Enrichment Corp will be released from its guarantee without the consent of the holders of the PIK Toggle Notes upon the occurrence of certain termination events (other than with respect to an unconditional interest claim), including (i) the involuntary termination by the Pension Benefit Guaranty Corporation (“PBGC”) of any of the qualified pension plans of the Company or Enrichment Corp, (ii) the cessation of funding prior to completion of our ongoing American Centrifuge test programs or (iii) both a decision by the Company to abandon American Centrifuge technology and either (1) the efforts by the Company to commercialize another next generation enrichment technology funded at least in part by new capital provided or to be provided by Enrichment Corp have been terminated or are no longer being pursued or (2) the attainment of capital necessary to commercialize another next generation enrichment technology with respect to which the Issuer is involved which does not include new capital provided or to be provided by Enrichment Corp. The Enrichment Corp. guarantee ranks equally in right of payment with all existing and future unsubordinated indebtedness of Enrichment Corp. (other than the Designated Senior Claims as defined below) and is senior in right of payment to all existing and future subordinated indebtedness of Enrichment Corp. The Enrichment Corp. guarantee is subordinated in right of payment to certain obligations of, and claims against, Enrichment Corp. described in the Indenture (collectively, the “Designated Senior Claims”), including obligations and claims: • under a future credit facility; • held by or for the benefit of the PBGC pursuant to any settlement of any actual or alleged Employee Retirement Income Security Act (“ERISA”) Section 4062(e) event; • held by any party with respect to any equity investment (or any commitment to make an equity investment) with respect to the financing of the American Centrifuge project; • held by DOE, export credit agencies or any other lenders or insurers with respect to the financing or government support of the American Centrifuge project; and • held by the U.S. government.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	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. The accounting guidance establishes a fair value hierarchy based on the level of independent, objective evidence surrounding the inputs used to measure fair value: • 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 (in Millions) December 31, 2016 December 31, 2015 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets: Cash and cash equivalents $ 260.7 $ — $ — $ 260.7 $ 234.0 $ — $ — $ 234.0 Deferred compensation asset (a) 1.1 — — 1.1 — 1.5 — 1.5 Liabilities: Deferred compensation obligation (a) 1.1 — — 1.1 — 1.4 — 1.4 (a) The deferred compensation obligation represents the balance of deferred compensation plus net investment earnings. The deferred compensation plan is funded through a rabbi trust. As of December 31, 2016, trust funds were invested in mutual funds for which unit prices are quoted in active markets and are classified within Level 1 of the valuation hierarchy. As of December 31, 2015, the trust was informally funded using variable universal life insurance. The cash surrender value of the life insurance policies was designed to track the deemed investments of the plan participants. Investment crediting options consisted of institutional and retail investment funds. The deemed investments were 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. The transfers from Level 2 to Level 1 noted above comprised the only transfers between Levels 1, 2 or 3 during the periods presented. Other Financial Instruments As of December 31, 2016 , and December 31, 2015, the balance sheet carrying amounts for accounts receivable, accounts payable and accrued liabilities (excluding the deferred compensation obligation described above), and payables under SWU purchase agreements approximate fair value because of the short-term nature of the instruments. The principal balance and estimated fair value of the PIK Toggle Notes follow (in millions): December 31, 2016 2015 Principal balance $ 234.6 $ 247.6 Estimated fair value 107.4 36.9 The estimated fair value of the PIK Toggle Notes is based on the most recent trading price as of the balance sheet date (Level 1).

Pension and Postretirement Heal

Pension and Postretirement Health and Life Benefits	12 Months Ended
	Dec. 31, 2016
General Discussion of Pension and Other Postretirement Benefits [Abstract]
Pension and Postretirement Health and Life Benefits	PENSION AND POSTRETIREMENT HEALTH AND LIFE BENEFITS There are approximately 5,000 employees and retirees covered by qualified defined benefit pension plans providing retirement benefits based on compensation and years of service, and approximately 4,000 employees, retirees and dependents covered by postretirement health and life benefit plans. DOE retained the obligation for postretirement health and life benefits for workers who retired prior to July 28, 1998. Pursuant to non-qualified supplemental pension plans, Centrus provides certain executive officers additional retirement benefits in excess of qualified plan limits imposed by tax law based on a targeted benefit objective. Employees hired on or after September 1, 2008 who are not covered by a collective bargaining agreement that provides for participation do not participate in a qualified defined benefit pension plan or postretirement health and life benefit plans. Changes in the projected benefit obligations and plan assets and the funded status of the plans follow (in millions): Defined Benefit Pension Plans Postretirement Health and Life Benefit Plans Year Ended December 31, Year Ended December 31, 2016 2015 2016 2015 Changes in Benefit Obligations: Obligations at beginning of period $ 832.8 $ 961.4 $ 203.5 $ 237.7 Actuarial (gains) losses, net 19.1 (55.2 ) (9.2 ) (30.2 ) Service costs 3.8 5.8 — 0.2 Interest costs 35.4 36.9 8.2 8.8 Benefits paid (60.9 ) (62.1 ) (13.3 ) (13.1 ) Lump sum benefits paid (12.2 ) (50.6 ) — — Less federal subsidy on benefits paid — — — 0.1 Plan change — — 3.6 — Administrative expenses paid (3.4 ) (3.4 ) — — Obligations at end of period 814.6 832.8 192.8 203.5 Changes in Plan Assets: Fair value of plan assets at beginning of period 656.3 772.4 13.8 26.3 Actual return on plan assets 50.2 (8.0 ) 0.5 0.4 Company contributions 4.1 8.0 6.7 0.2 Benefits paid (60.9 ) (62.1 ) (13.3 ) (13.1 ) Lump sum benefits paid (12.2 ) (50.6 ) — — Administrative expenses paid (3.4 ) (3.4 ) — — Fair value of plan assets at end of period 634.1 656.3 7.7 13.8 (Unfunded) status at end of period (180.5 ) (176.5 ) (185.1 ) (189.7 ) Amounts recognized in assets and liabilities: Current liabilities $ (0.6 ) $ (4.2 ) (13.8 ) (5.4 ) Noncurrent liabilities (179.9 ) (172.3 ) (171.3 ) (184.3 ) $ (180.5 ) $ (176.5 ) $ (185.1 ) $ (189.7 ) Amounts in accumulated other comprehensive income (loss), pre-tax: Prior service cost (credit) $ — $ — $ (2.6 ) $ (6.6 ) Discount rate used to determine benefit obligations at end of period: 4.1% 4.5% 3.9% 4.2% The current liabilities reflect expected contributions for benefit payments for the non-qualified plans and the postretirement health and life benefit plans in the following year. The discount rates above, rounded to the nearest 0.1%, are the estimated rates at which the benefit obligations could be effectively settled on the measurement date and are based on yields of high quality fixed income investments whose cash flows match the timing and amount of expected benefit payments of the plans. Plan assets and benefit obligations are remeasured each year as of the balance sheet date resulting in differences between actual and projected results for the year. These actuarial gains and losses are recognized in the statement of operations in the fourth quarter. In addition, an interim remeasurement and recognition of gains or losses may be required for a plan during the year when lump-sum payments exceed, or are expected to exceed, the sum of the service cost and interest cost components of the annual net periodic benefit cost for that plan for the current year. The defined benefit pension plans currently allow for a lump sum payment option to (a) active employees who are terminated as a result of company reductions in force and (b) periodically to terminated vested participants. The lump sum payment option was most recently extended through September 2019 to those terminated vested participants who have not yet begun receiving their benefits and have been terminated as a result of a reduction in force by the Company, or due to voluntary termination or involuntary termination, other than involuntary termination as a termination for cause. Projected benefit obligations are based on actuarial assumptions including possible future increases in compensation. Accumulated benefit obligations are based on actuarial assumptions but do not include possible future increases in compensation. Effective August 2013, accrued benefits under the defined benefit pension plans are fixed and no longer increase to reflect changes in compensation or company service. Therefore, the accumulated benefit obligation equaled the projected benefit obligation of $814.6 million as of December 31, 2016, and $832.8 million as of December 31, 2015. As of December 31, 2016, none of Centrus’ plans had fair value of plan assets in excess of accumulated benefit obligations. Components of Net Periodic Benefit Costs and Other Amounts Recognized in Other Comprehensive Loss (in millions) Defined Benefit Pension Plans Postretirement Health and Life Benefit Plans Year Ended December 31, Year Ended December 31, 2016 2015 2016 2015 Net Periodic Benefit Costs Service costs $ 3.8 $ 5.8 $ — $ 0.2 Interest costs 35.4 36.9 8.2 8.8 Expected return on plan assets (gains) (42.0 ) (47.4 ) (0.3 ) (0.8 ) Actuarial (gains) losses, net 10.9 0.2 (9.5 ) (29.8 ) Amortization of prior service costs (credits), net — — (0.3 ) (0.3 ) Net periodic benefit costs (credits) $ 8.1 $ (4.5 ) $ (1.9 ) $ (21.9 ) Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss) Net prior service costs (credits) — — 3.6 — Amortization of prior service (costs) credits, net — — 0.3 0.3 Total (gain) loss recognized in other comprehensive income (loss), pre-tax $ — $ — $ 3.9 $ 0.3 Total recognized in net periodic benefit costs (income) and other comprehensive income (loss), pre-tax $ 8.1 $ (4.5 ) $ 2.0 $ (21.6 ) Defined Benefit Pension Plans Postretirement Health and Life Benefit Plans Year Ended December 31, Year Ended December 31, 2016 2015 2016 2015 Assumptions used to determine net periodic benefit costs: Discount rate 4.1% 4.5% 3.9% 4.2% Expected return on plan assets 6.8% 6.8% 5.0% 5.3% Net periodic benefit costs include service and interest costs of providing pension benefits that are accrued over the years employees render service. Prior service costs or credits are amortized over the employees’ average remaining years of service from age 40 until the date of full benefit eligibility or the average expected future lifetime of all plan participants, as applicable. Participants in the postretirement health and life benefit plans are generally eligible for benefits at retirement after age 50 with 10 years of continuous credited service at the time of retirement. The expected return on plan assets is based on the weighted average of long-term return expectations for the composition of the plans’ equity and debt securities. Expected returns on equity securities are based on historical long-term returns of equity markets. Expected returns on debt securities are based on the current interest rate environment. Benefit obligations and prior service costs for the postretirement health and life benefit plans increased $3.6 million in 2016 as a result of a plan change increasing the stipend amount provided by Centrus to Medicare-eligible participants. Net periodic benefit costs and actuarial gains and losses are allocated to cost of sales for the LEU segment and to selling, general and administrative expense. Healthcare cost trend rates used to measure postretirement health benefit obligations follow: December 31, 2016 2015 Healthcare cost trend rate for the following year 7% 7.5% Long-term rate that the healthcare cost trend rate gradually declines to 5% 5% Year that the healthcare cost trend rate is expected to reach the long-term rate 2021 2021 A one-percentage-point change in the assumed healthcare cost trend rates would have an effect on the postretirement health benefit obligation and costs of the Successor Company, as follows (in millions): One Percentage Point Increase Decrease Postretirement health benefit obligation $ 4.0 $ (3.8 ) Net periodic benefit costs (service and interest cost components only) $ 0.3 $ (0.3 ) Benefit Plan Assets Independent advisors manage investment assets of Centrus’ defined benefit pension plans and postretirement health and life benefit plans. Centrus has the fiduciary responsibility for reviewing performance of the various investment advisors. The investment policy of the plans is to maximize portfolio returns within reasonable and prudent levels of risk in order to meet projected liabilities and maintain sufficient cash to make timely payments of all participant benefits. Risk is reduced by diversifying plan assets in a broad mix of asset classes and by following a strategic asset allocation approach. Asset classes and target weights are adjusted periodically to optimize the long-term portfolio risk/return tradeoff, to provide liquidity for benefit payments, and to align portfolio risk with the underlying obligations. The investment policy of the plans prohibits the use of leverage, direct investments in tangible assets, or any investment prohibited by applicable laws or regulations. The allocation of plan assets between equity and debt securities and the target allocation range by asset category follows: December 31, 2016 2015 2017 Target Defined Benefit Pension Plans: Equity securities 41 % 47 % 40 - 60% Debt securities 59 53 40 - 60 100 % 100 % Postretirement Health and Life Benefit Plans: Equity securities 100 % 64 % 85 - 100% Debt securities 0 36 0 - 15 100 % 100 % Plan assets are measured at fair value. Following are the plan investments as of December 31, 2016, and December 31, 2015, categorized by the fair value hierarchy levels described in Note 10, Fair Value Measurements, (in millions): Defined Benefit Pension Plans Level 1 Level 2 Level 3 Total 2016 2015 2016 2015 2016 2015 2016 2015 U.S. government securities $ — $ — $ 84.7 $ 61.8 $ — $ — $ 84.7 $ 61.8 Corporate debt — — 217.0 206.9 — — 217.0 206.9 Municipal bonds — — 6.2 6.8 — — 6.2 6.8 Mortgage and asset backed securities — — 5.4 — — — 5.4 — Fair value of investments by hierarchy level $ — $ — $ 313.3 $ 275.5 $ — $ — $ 313.3 $ 275.5 Investments measured at NAV (a) 318.3 377.2 Accrued interest receivable 3.5 3.5 Unsettled transactions (1.0 ) 0.1 Plan assets $ 634.1 $ 656.3 Postretirement Health and Life Benefit Plans Level 1 Level 2 Level 3 Total 2016 2015 2016 2015 2016 2015 2016 2015 Money market funds $ 0.2 $ 1.0 $ — $ — $ — $ — $ 0.2 $ 1.0 Bond mutual funds 7.5 4.0 — — — — 7.5 4.0 Equity mutual funds — 8.8 — — — — — 8.8 Fair value of investments by hierarchy level $ 7.7 $ 13.8 $ — $ — $ — $ — $ 7.7 $ 13.8 (a) Equity, bond and money market investments held in collective trusts are valued based on the net asset value (“NAV”) provided by the administrator of the funds. The NAV for each fund is based on the underlying assets owned by the fund, less any expenses accrued against the fund, divided by the number of fund shares outstanding. While the underlying investments are traded on an exchange, the funds are not. Fair values for the collective trust investments are measured using the NAVs as a practical expedient and are not categorized in the fair value hierarchy. Level 1 assets consist of mutual funds and money market funds having a publicly available NAV. Level 2 assets include investments in U.S. government agency securities, corporate and municipal debt that are valued based on estimated prices using observable, market-based inputs. Benefit Plan Cash Flows Centrus expects to contribute $1.1 million to the qualified defined benefit pension plans, $0.6 million to the non-qualified defined benefit pension plans and $13.8 million to the postretirement health and life benefit plans in 2017. There is no required contribution for the postretirement health and life benefit plans under Employee Retirement Income Security Act (“ERISA”). Estimated future benefit plan payments follow (in millions): Defined Benefit Pension Plans Postretirement Health and Life Benefit Plans 2017 $ 60.4 $ 21.5 2018 59.4 20.4 2019 58.0 19.0 2020 56.1 17.2 2021 55.0 15.8 2022 to 2026 258.9 61.3 Other Plans Centrus sponsors a 401(k) defined contribution plan for employees. Employee contributions are matched at established rates. Amounts contributed are invested in a range of investment options available to participants and the funds are administered by an independent trustee. Matching cash contributions by the Company amounted to $2.4 million in 2016 and $3.0 million in 2015. Under the Executive Deferred Compensation Plan, qualified employees may defer compensation on a tax-deferred basis subject to plan limitations. Any matching contributions under the Company’s 401(k) plan that are foregone due to annual compensation limitations of the Internal Revenue Code are eligible to be received from the Company under the Executive Deferred Compensation Plan, provided that the employee deferred the maximum allowable pre-tax contribution in the 401(k) plan . Centrus matching contributions amounted to less than $0.1 million in 2016 and 2015.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2016
Share-based Compensation [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION The Company’s 2014 Equity Incentive Plan authorizes the issuance stock options, stock appreciation rights, restricted stock units, restricted stock, performance awards, dividend equivalent rights and other stock based awards, as well as cash-based awards to employees, officers, directors and other individuals providing services to the Company or its affiliates. The plan authorizes the issuance of up to 1,000,000 shares of Class A Common Stock. As of December 31, 2016, there were approximately 414,000 shares available for future awards, including approximately 63,000 shares associated with awards which terminated or were cancelled without being exercised. A summary of stock-based compensation costs follows (in millions): Year Ended December 31, 2016 2015 Total stock-based compensation costs: Restricted stock units $ 0.2 $ 0.2 Stock options 0.3 0.2 Expense included in selling, general and administrative expense $ 0.5 $ 0.4 Total recognized tax benefit $ — $ — The total recognized tax benefit is reported at the federal statutory rate net of the tax valuation allowance. As of December 31, 2016, there was $0.7 million of unrecognized compensation cost, adjusted for estimated forfeitures, related to non-vested stock-based payments granted, of which $0.7 million relates to stock options and less than $0.1 million relates to restricted stock units. That cost is expected to be recognized over a weighted-average period of 1.8 years. 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, on a straight-line basis the over the vesting period. Restricted Stock Units Non-employee, independent directors are granted restricted stock units as part of their compensation for serving on the Board of Directors. Settlement of these restricted stock units is made in shares of Class A Common Stock only upon the director’s retirement or other end of service. The restricted stock units vest over one year; however, vesting is accelerated upon (1) the director attaining eligibility for retirement, (2) termination of the director’s service by reason of death or disability, or (3) a change in control. As of December 31, 2016, approximately 103,300 shares of restricted stock units could potentially become Class A Common Stock once vested and settled. The fair value of restricted stock units is determined based on the closing price of Class A Common Stock on the grant date. Compensation cost for restricted stock units is amortized to expense on a straight-line basis over the vesting period. Stock Options The intrinsic value of an option, if any, represents the excess of the fair value of the common stock over the exercise price. The fair value of stock option awards is estimated using the Black-Scholes option pricing model, which includes a number of assumptions including Centrus’ estimates of stock price volatility, employee stock option exercise behaviors, future dividend payments, and risk-free interest rates. The expected term of options granted is the estimated period of time from the beginning of the vesting period to the date of expected exercise or other settlement, based on historical exercises and post-vesting terminations. Centrus has estimated the expected term using the simplified method described in SEC Staff Accounting Bulletin No. 107/110, Share-Based Payment , due to the lack of historical exercise and post-vesting termination information available for the Company since its reorganization. Future stock price volatility is estimated based on the Company’s historical volatility. The risk-free interest rate for the expected option term is based on the U.S. Treasury yield curve in effect at the time of grant. No cash dividends are expected in the foreseeable future and, therefore, an expected dividend yield of zero is used in the option valuation model. Historical data are used to estimate pre-vesting option forfeitures at the time of grant. Estimates for option forfeitures are revised in subsequent periods if actual forfeitures differ from those estimates. Compensation expense is recognized for stock option awards that are expected to vest. Assumptions used in the Black-Scholes option pricing model to value option grants follow: Year Ended December 31, 2016 2015 Risk-free interest rate 1.91% 1.91% Expected volatility 75% 75% Expected option life (years) 6 6 Weighted-average grant date fair value $1.77 $2.62 Options granted (in thousands) 15 437 Stock options vest and become exercisable in equal annual installments over a three or four year period and expire ten years from the date of grant. A summary of stock option activity follows: Stock Options (thousands) Weighted Average Exercise Price Weighted Average Remaining Contractual Life in Years Aggregate Intrinsic Value (millions) Outstanding at December 31, 2015 475 $4.09 9.3 $— Granted 15 $2.68 Exercised — — Forfeited/Cancelled (7) $5.62 Outstanding at December 31, 2016 483 $4.02 8.4 $1.1 Exercisable at December 31, 2016 141 $4.12 8.3 $0.3 Stock options outstanding and options exercisable at December 31, 2016, follow: Stock Exercise Price Options Outstanding (thousands) Weighted Average Remaining Contractual Life in Years Options Exercisable (thousands) $5.62 30 7.9 20.0 $4.37 300 8.2 75.0 $3.90 23 8.6 8.0 $3.93 15 8.6 5.0 $2.71 50 8.8 16.0 $2.75 50 8.8 17.0 $2.68 15 9.5 —

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Provision (Benefit) The provision (benefit) for income taxes from continuing operations is as follows (in millions): Year Ended December 31, 2016 2015 Current: Federal $ — $ — State and local (0.6 ) (0.3 ) Foreign — — (0.6 ) (0.3 ) Deferred: Federal — — State and local — — Foreign — — — — $ (0.6 ) $ (0.3 ) Deferred Taxes Future tax consequences of temporary differences between the carrying amounts for financial reporting purposes and the Company’s estimate of the tax bases of its assets and liabilities result in deferred tax assets and liabilities, as follows (in millions): December 31, 2016 2015 Deferred tax assets: Employee benefits costs $ 139.3 $ 140.8 Inventory — 3.1 Property, plant and equipment 318.8 437.1 Net operating loss and credit carryforwards 254.9 114.3 Accrued expenses 14.9 9.1 Other 12.6 11.9 740.5 716.3 Valuation allowance (702.2 ) (676.4 ) Deferred tax assets, net of valuation allowance $ 38.3 $ 39.9 Deferred tax liabilities: Inventory $ 2.6 $ — Intangible assets 33.0 37.3 Prepaid expenses 2.7 2.6 Deferred tax liabilities $ 38.3 $ 39.9 $ — $ — The valuation allowance reduces the net deferred tax assets to their net realizable value. There is a full valuation allowance against net deferred taxes due to annual losses since 2011 and substantial uncertainty to generate future taxable income that would lead to realization of the net deferred tax assets. The ultimate realization of the net deferred tax assets is dependent upon generating sufficient taxable income in future years when deferred tax assets are recoverable or are expected to reverse. Centrus has federal net operating losses of $725.8 million that currently expire through 2036. The federal net operating losses as well as other tax attributes consisting primarily of tax basis in property of approximately $15.3 million have been reduced as a result of Centrus’ cancellation of debt income of approximately $340 million as prescribed by Internal Revenue Code Section 108. Centrus also has state net operating losses of $17.7 million that currently expire in 2036. The deferred tax assets for state net operating losses and state unrealized built-in loss deductions have been reduced as a result of Centrus’ ownership change and cancellation of debt income in 2014. Centrus experienced an ownership change as defined under Internal Revenue Code Section 382 on September 30, 2014 when it emerged from bankruptcy. Generally, after an ownership change, the use of federal and state net operating loss carryforwards and tax credits generated prior to the ownership change are subject to an annual limitation. However, there is an exception available to qualifying corporations that eliminates the annual limitation. Centrus is able to utilize this exception for federal purposes, but not for state purposes. The pre-apportioned annual state limitation is $2.9 million . Centrus also had an unrealized built-in loss as of the ownership change date. To the extent this built-in loss is recognized during the five-year period following the ownership change through certain depreciation and loss deductions, the same annual limitation for loss and tax credit carryforwards generally also applies to a built-in loss when it is recognized, unless the exception applies. Centrus is able to utilize the same exception for federal purposes when the built-in loss is recognized, but not for state purposes. To the extent the built-in loss is recognized during the five-year post-ownership change period, the same pre-apportioned annual state limitation will apply so that the combination of loss carryforwards and recognized built-in losses cannot exceed $2.9 million. Effective Tax Rate A reconciliation of income taxes calculated based on the federal statutory income tax rate of 35% and the effective tax rate follows: Year Ended December 31, 2016 2015 Federal statutory tax rate 35 % 35 % Gain on early extinguishment of debt 6 — Excess reorganization value — (26 ) Interest expense (3 ) (1 ) Valuation allowance against deferred tax assets (36 ) (9 ) State rate changes and tax attributes (1 ) 1 1 % — % The effective tax rate for the year ended December 31, 2016, includes an adjustment to the valuation allowance against net deferred tax assets of $24.4 million , or 36%. The effective tax rate for the year ended December 31, 2015, includes an adjustment to the excess reorganization value of $137.2 million or 26%, and an adjustment to the valuation allowance against net deferred tax assets of $16.8 million , or 9%. Uncertain Tax Positions Accounting standards require that a tax position meet a minimum recognition threshold in order for the related tax benefit to be recognized in the financial statements. The liability for unrecognized tax benefits, included in other long-term liabilities, was $0.4 million as of December 31, 2016 and $1.0 million as of December 31, 2015. If recognized, these tax benefits would impact the effective tax rate. As a result of changes to unrecognized tax benefits, the tax provision (state tax, net of federal benefit) decreased $0.4 million during the year ended December 31, 2016 and $0.2 million during the year ended December 31, 2015. The liability for unrecognized tax benefits in the table below relates to state tax unrecognized tax benefits. Centrus believes that the liability for unrecognized tax benefits will be reduced by $0.2 million in the next 12 months. A reconciliation of the beginning and ending amount of unrecognized tax benefits follows (in millions): Year Ended December 31, 2016 2015 Balance at beginning of the period $ 1.0 $ 1.3 Additions to tax positions of current period — — Reductions to tax positions of prior years (0.6 ) (0.3 ) Balance at end of the period $ 0.4 $ 1.0 Centrus and its subsidiaries file income tax returns with the U.S. government and various states and foreign jurisdictions. The IRS started an examination of Centrus’ 2008 through 2011 federal income tax returns during 2012 that was completed in the second quarter of 2014 with no adjustment to the reported tax. As of December 31, 2016, the federal and Maryland statutes of limitation are closed with respect to all tax years through 2012, and the Kentucky statute of limitations is closed with respect to all tax years through 2011. Centrus recognizes accrued interest related to uncertain tax positions as a component of interest expense. Reversals of previously accrued interest for income taxes is typically offset against interest expense, but if the amount is significant, it is reclassified to interest income in the consolidated statement of operations. Centrus recognizes the increase or decrease of accrued penalties for income taxes as a component of selling, general and administrative expense in the consolidated statement of operations. The impact of accrued interest and penalties for income taxes in the consolidated statement of operations was a reduction to expenses of $0.1 million for years ended December 31, 2016 and 2015. Accrued interest and penalties for income taxes, included as a component of accounts payable and accrued liabilities, totaled $0.1 million as of December 31, 2016, and $0.2 million as of December 31, 2015.

Net Income Per Share

Net Income Per Share	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	NET 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 and dividends on potentially dilutive securities, net of tax, and the denominator is increased by the weighted average number of shares resulting from potentially dilutive securities, assuming full conversion. No dilutive effect is recognized in a period in which a net loss has occurred. Year Ended December 31, (in millions, except per share amounts) 2016 2015 Numerator for basic and diluted calculation: Net loss $ (67.0 ) $ (187.4 ) Denominator: Weighted average common shares 9.1 9.0 Denominator for basic calculation 9.1 9.0 Weighted average effect of dilutive securities: Stock compensation awards (a) — — Denominator for diluted calculation 9.1 9.0 Net loss per share - basic and diluted $ (7.36 ) $ (20.82 ) (a) Compensation awards under the 2014 Equity Incentive Plan resulted in common stock equivalents of less than 0.1 million shares of common stock and are excluded from the diluted calculation as a result of net losses in the years ended December 31, 2016 and 2015. 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: Year Ended December 31, 2016 2015 Options excluded from diluted net income per share 368,000 375,000 Exercise price of excluded options $ 3.90 to $ 3.90 to $ 5.62 $ 5.62

Stockholders' Equity (Notes)

Stockholders' Equity (Notes)	12 Months Ended
	Dec. 31, 2016
Stockholders' Equity Attributable to Parent [Abstract]
Stockholders' Equity Note Disclosure [Text Block]	STOCKHOLDERS’ EQUITY The Company’s certificate of incorporation authorizes 20,000,000 shares of preferred stock, par value $1.00 per share, 70,000,000 shares of Class A common stock, $0.10 par value per share (the “Class A Common Stock”) and 30,000,000 shares of Class B common stock, $0.10 par value per share (the “Class B Common Stock,” and together with the Class A Common Stock, the “Common Stock”). The Company has issued 9,000,000 shares of Common Stock, consisting of 7,563,600 shares of Class A Common Stock and 1,436,400 shares of Class B Common Stock. There were no shares issued in 2015 or 2016. The Company has reserved 1,000,000 shares of Class A Common Stock under its management incentive plan, of which approximately 414,000 shares are available for future awards as of December 31, 2016. Refer to Note 12, Stock-Based Compensation , for additional information. The Class A Common Stock trades under the symbol “LEU” on the NYSE’s MKT trading platform. Refer to Note 16, Commitments and Contingencies - NYSE MKT Listing Standards Notice. The Class B Common Stock was issued to Toshiba America Nuclear Energy Corporation (“Toshiba” ) and Babcock & Wilcox Investment Company (“B&W”) and has the same rights, powers, preferences and restrictions and ranks equally in all matters with the Class A Common Stock, except voting. Holders of Class B Common Stock are entitled to elect, in the aggregate, two members of the Board of Directors of the Company, subject to certain holding requirements. Rights Agreement On April 6, 2016 (the “Effective Date”), the Company’s Board of Directors (the “Board”) adopted a Section 382 Rights Agreement (the “Rights Agreement”). The Board adopted the Rights Agreement in an effort to protect shareholder value by, among other things, attempting to protect against a possible limitation on the Company’s ability to use its net operating loss carryforwards and other tax benefits, which may be used to reduce potential future income tax obligations. As of December 31, 2016, the Company had federal net operating losses of $725.8 million that currently expire through 2036. In connection with the adoption of the Rights Agreement, the Board declared a dividend of one preferred-share-purchase-right for each share of the Company’s Class A common stock and Class B common stock outstanding as of the Effective Date. The rights initially trade together with the common stock and are not exercisable. In the absence of further action by the Board, the rights would generally become exercisable and allow a holder to acquire shares of a new series of the Company’s preferred stock if any person or group acquires 4.99% or more of the outstanding shares of the Company’s common stock, or if a person or group that already owns 4.99% or more of the Company’s Class A common stock acquires additional shares representing 0.5% or more of the outstanding shares of the Company’s Class A common stock. The rights beneficially owned by the acquirer would become null and void, resulting in significant dilution in the ownership interest of such acquirer. The Board may exempt any acquisition of the Company’s common stock from the provisions of the Rights Agreement if it determines that doing so would not jeopardize or endanger the Company’s use of its tax assets or is otherwise in the best interests of the Company. The Board also has the ability to amend or terminate the Rights Agreement prior to a triggering event.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Commitments under SWU Purchase Agreement The Company’s leading supplier of SWU is the Russian government entity Joint Stock Company “TENEX” (“TENEX”). Under a 2011 agreement with TENEX (the “Russian Supply Agreement”), the Company purchases SWU contained in LEU received from TENEX, and the Company delivers natural uranium to TENEX for the LEU’s uranium component. The LEU that Centrus obtains from TENEX under the agreement is subject to quotas and other restrictions applicable to commercial Russian LEU. In December 2015, the Company successfully negotiated an amendment to the Russian Supply Agreement to better align the Company’s purchase obligations in light of market conditions generally, the Company’s sales order book, and restrictions on the import of Russian LEU. The amendment extended the Russian Supply Agreement beyond 2022 and gives the Company the right to reschedule quantities of SWU into the period 2023-2026, in return for the purchase of additional SWU in those years. Depending on the total purchase obligations rescheduled to 2023-2026, the Company may defer certain limited quantities beyond 2026. The amended agreement provides that the Company must pay for all SWU in its minimum purchase obligation each year, even if it fails to submit orders for such SWU. The Company would then have the right to take the unordered SWU in the following year. The December 2015 modification did not change the pricing terms for SWU under the Russian Supply Agreement, which are based on a mix of market-related price points and other factors. Potential ERISA Section 4062(e) Liability The Company had been engaged in discussions with the PBGC regarding the status of the qualified pension plans, including potential liabilities under ERISA Section 4062(e) related to employee reductions resulting from ceasing enrichment operations at the Portsmouth and Paducah GDP facilities. In February 2017, the PBGC confirmed that given changes to ERISA Section 4062(e) enacted by Congress in recent years, the Company is able to waive liability with respect to employee reductions at the Portsmouth and Paducah GDP facilities. In addition, the PBGC stated that it agrees to forbear from future action under ERISA Section 4062(e) related to the American Centrifuge project. In its notification to the Company, the PBGC cited the positive results of the Company’s exchange offer and consent solicitation described in Note 19, Subsequent Event. NYSE MKT Listing Standards Notice On November 17, 2015, Centrus Energy Corp. received notice from the NYSE MKT LLC (the “NYSE MKT”) indicating that the Company is not in compliance with Sections 1003(a)(i) and (ii) of the NYSE MKT’s Company Guide since the Company reported a stockholders’ deficit as of September 30, 2015, and net losses in its fiscal years ended December 31, 2011, 2012 and 2013. The Company submitted a plan to regain compliance with the NYSE MKT’s continued listing standards and the NYSE MKT notified the Company in January 2016 that it accepted the plan. With the NYSE MKT’s acceptance of the plan, the Company has until May 17, 2017, to regain compliance. If the Company is not in compliance with the continued listing standards by May 17, 2017, or if the Company does not make progress consistent with the plan, the NYSE MKT may initiate delisting procedures as appropriate. In the meantime, the Company’s common stock will continue to be traded on the NYSE MKT, subject to ongoing monitoring by the NYSE MKT and the Company’s compliance with all other applicable NYSE MKT requirements. American Centrifuge Milestones under the 2002 DOE-USEC Agreement USEC and DOE signed an agreement dated June 17, 2002, as amended (the “2002 DOE-USEC Agreement”), pursuant to which the parties made long-term commitments directed at resolving issues related to the stability and security of the domestic uranium enrichment industry. DOE consented to the assumption by Centrus of the 2002 DOE-USEC Agreement and other agreements between the Company and DOE subject to an express reservation of all rights, remedies and defenses by DOE and Centrus under those agreements as part of Centrus’ Chapter 11 bankruptcy process. The 2002 DOE-USEC Agreement requires Centrus to 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. DOE has specific remedies under the 2002 DOE-USEC Agreement if Centrus fails to meet a milestone that would adversely impact its ability to begin commercial operations of the American Centrifuge Plant on schedule, and such delay was within Centrus’ control or was due to its fault or negligence or if Centrus abandons or constructively abandons the commercial deployment of an advanced enrichment technology. These remedies include terminating the 2002 DOE-USEC Agreement, revoking Centrus’ access to DOE’s centrifuge technology that is required for the success of the American Centrifuge project, requiring Centrus to transfer certain rights in the American Centrifuge technology and facilities to DOE, and requiring Centrus to reimburse DOE for certain costs associated with the American Centrifuge project. The 2002 DOE-USEC Agreement provides that if a delaying event beyond the control and without the fault or negligence of Centrus occurs that could affect Centrus’ ability to meet an American Centrifuge Plant milestone, DOE and Centrus will jointly meet to discuss in good faith possible adjustments to the milestones as appropriate to accommodate the delaying event. The Company notified DOE that it had not met the June 2014 milestone within the time period currently provided due to events beyond its control and without the fault or negligence of the Company. The assumption of the 2002 DOE-USEC Agreement provided for under the Plan of Reorganization did not affect the ability of either party to assert all rights, remedies and defenses under the agreement and all such rights, remedies and defenses are specifically preserved and all time limits tolled expressly including all rights, remedies and defenses and time limits relating to any missed milestones. DOE and Centrus have agreed that all rights, remedies and defenses of the parties with respect to any missed milestones since March 5, 2014, including the June 2014 and November 2014 milestones, and all other matters under the 2002 DOE-USEC Agreement continued to be preserved, and that the time limits for each party to respond to any missed milestones continue to be tolled. Piketon Facility Costs and D&D Obligations Effective October 1, 2015, the U.S. government discontinued funding of the American Centrifuge demonstration cascade at Piketon. Funding for American Centrifuge is now limited to research and development work at our facilities in Oak Ridge, Tennessee. As a result of reduced program funding, Centrus incurred a special charge in the third quarter of 2015 for estimated employee termination benefits, and began reductions in force. Refer to Note 2 , Special Charges , for details. Centrus began to incur expenditures in the second quarter of 2016 associated with the D&D of the Piketon facility in accordance with the requirements of the NRC and DOE. Centrus leases the Piketon facility from DOE. At the conclusion of the lease, Centrus is obligated to return the facility to DOE in a condition that meets NRC requirements and in the same condition as the facility was in when it was leased to Centrus (other than due to normal wear and tear). Centrus must remove all Company-owned capital improvements at the Piketon facility, unless otherwise consented to by DOE, by the conclusion of the lease term. The lease will expire on June 30, 2019, unless it is extended. The D&D work is expected to extend through 2017 and be substantially completed by year-end. As of December 31, 2016, we have accrued $38.6 million on the balance sheet as Decontamination and Decommissioning Obligations for the estimated fair value of the remaining costs to complete the D&D work. Centrus is required to provide financial assurance to the NRC and DOE for D&D costs under a regulatorily-prescribed methodology that includes potential contingent costs and reserves. As of December 31, 2016, Centrus has provided financial assurance to the NRC and DOE in the form of surety bonds totaling $29.4 million , which are fully cash collateralized by Centrus. Centrus expects to receive cash when surety bonds are reduced and/or cancelled as the Company fulfills its D&D and lease obligations. Waste Disposition The Company’s prior enrichment operations generated hazardous, low-level radioactive and mixed wastes. The treatment and disposal of wastes from our prior operations at the Paducah GDP was completed in 2016. For the former Portsmouth GDP in Piketon, Ohio, DOE agreed in 2011 to accept ownership of all nuclear material at the site, some of which required processing for waste disposal. We agreed to pay DOE for costs for disposing of our share of such wastes. Centrus’ liability for the processing of remaining waste quantities was $0.2 million at December 31, 2016, and $0.7 million at December 31, 2015. The USEC Privatization Act and our lease with DOE provide that DOE remains responsible for the decontamination and decommissioning of the Paducah and Portsmouth sites. Legal Matters Centrus 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, Centrus does not believe that the outcome of any of these legal matters will have a material adverse effect on its results of operations or financial condition. Lease Commitments Expenses under operating leases for office space, equipment and the Piketon and Oak Ridge facilities amounted to $2.9 million in 2016 and $4.3 million in 2015. Future estimated minimum lease payments and expected lease administration payments follow (in millions): 2017 $ 3.1 2018 2.4 2019 1.6 2020 0.9 2021 0.9 Thereafter 5.7 $ 14.6 Centrus has a lease with DOE for centrifuge testing facilities in Oak Ridge through December 2017. Centrus leases facilities in Piketon for the American Centrifuge Plant from DOE. The current five-year lease term is through June 2019. Centrus has the option to extend the lease term for additional five-year terms. DOE may terminate the lease for default, including if DOE is able to exercise its remedies with respect to the ACP under the 2002 DOE-USEC Agreement. Centrus leases the office space for its corporate headquarters in Bethesda, Maryland through October 2027 with an option to extend for five years.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income (Loss) (Notes)	12 Months Ended
	Dec. 31, 2016
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) (“AOCI”) relates to activity in the accounting for pension and postretirement health and life benefit plans. Prior service cost arising during the period and amortization of prior service credits are items reclassified from AOCI and included in the computation of net periodic benefit cost as detailed in Note 11, Pension and Postretirement Health and Life Benefits .

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2016
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Segment Information	REVENUE BY GEOGRAPHIC AREA, MAJOR CUSTOMERS AND SEGMENT INFORMATION Revenue attributed to domestic and foreign customers, including customers in a foreign country representing 10% or more of total revenue, follows (in millions): Year Ended December 31, 2016 2015 United States $ 242.8 $ 272.8 Foreign: Japan 49.1 77.8 Belgium * 55.5 Other 19.4 12.1 68.5 145.4 Total revenue $ 311.3 $ 418.2 * less than 10% In 2016, our 10 largest customers represented approximately 90% of total revenue and our four largest customers represented approximately 50% of total revenue. In our LEU segment, revenue from Exelon Corporation, South Carolina Electric & Gas and American Electric Power represented approximately 15% , 12% and 11% , respectively, of total revenue in 2016. In 2015, revenue from Exelon Corporation, Synatom S.A. and Kansai Electric Power Co., Inc. represented approximately 25% , 13% , and 10% , respectively, of total revenue. In our contract services segment, the U.S. government and its contractors represented approximately 12% of total revenue in 2016 and 15% of total revenue in 2015. No other customer represented more than 10% of total revenue in 2016 or 2015. Centrus has two reportable segments: the LEU segment with two components, SWU and uranium, and the contract services segment. The LEU segment 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 includes revenue and cost of sales for work that Centrus performs as a contractor to UT-Battelle. The contract services segment also includes limited services provided by Centrus to DOE and its contractors at the Portsmouth site related to facilities we continue to lease for the American Centrifuge Plant and formerly at the Paducah GDP. Gross profit is Centrus’ measure for segment reporting. There were no intersegment sales in the periods presented. Year Ended December 31, (in millions) 2016 2015 Revenue LEU segment: Separative work units $ 258.5 $ 289.9 Uranium 14.3 65.5 272.8 355.4 Contract services segment 38.5 62.8 Revenue $ 311.3 $ 418.2 Segment Gross Profit LEU segment $ 38.5 $ 70.1 Contract services segment 6.6 (1.2 ) Gross profit $ 45.1 $ 68.9 December 31, (in millions) 2016 2015 Assets LEU segment $ 686.0 $ 795.3 Contract services segment 27.5 24.8 $ 713.5 $ 820.1 Centrus’ long-term or long-lived assets include property, plant and equipment and other assets are reported on the balance sheet at December 31, 2016, all of which were located in the United States.

Subsequent Event (Notes)

Subsequent Event (Notes)	12 Months Ended
	Dec. 31, 2016
Subsequent Event [Abstract]
Subsequent Event	SUBSEQUENT EVENT On February 14, 2017, pursuant to an exchange offer and consent solicitation, Centrus exchanged $204.9 million of PIK Toggle Notes for $74.3 million of 8.25% Notes, 104,574 shares of Series B Preferred Stock with liquidation preference of $1,000 per share, and $27.6 million of cash, leaving $29.6 million of PIK Toggle Notes remaining outstanding. The Company anticipates that it will account for the exchange in the quarter ending March 31, 2017, as a troubled debt restructuring (“TDR”) under Accounting Standards Codification Subtopic 470-60, Debt-Troubled Debt Restructurings by Debtor s. For an exchange classified as a TDR, if the future undiscounted cash flows of the newly issued debt and other consideration are less than the net carrying value of the original debt, a gain is recorded for the difference and the carrying value of the newly issued debt is adjusted to the future undiscounted cash flow amount and no future interest expense is recorded. All future interest payments on the newly issued debt reduce the carrying value. The newly issued preferred stock is to be recorded at fair value less transaction costs. Accordingly, the Company expects to recognize the 8.25% Notes and the Series B Preferred Stock on the consolidated balance sheet at approximately $136 million and $5 million , respectively. The Company anticipates a gain related to the note exchange of approximately $34 million in its consolidated statement of operations for the quarter ending March 31, 2017, which is net of transaction costs related to the exchange of approximately $9 million incurred in the first quarter of 2017.

Quarterly Results of Operations

Quarterly Results of Operations (Notes)	12 Months Ended
	Dec. 31, 2016
Quarterly Results of Operations (Unaudited) [Abstract]
Quarterly Financial Information [Text Block]	QUARTERLY RESULTS OF OPERATIONS (Unaudited) (in millions, except per share data) 2016 1st Qtr. 2nd Qtr. 3rd Qtr. 4th Qtr. Year Revenue $ 90.0 $ 63.4 $ 21.4 $ 136.5 $ 311.3 Cost of sales 74.2 57.9 23.5 110.6 266.2 Gross profit (loss) 15.8 5.5 (2.1 ) 25.9 45.1 Advanced technology license and decommissioning costs 12.0 4.7 21.9 9.3 47.9 Selling, general and administrative 11.4 12.5 10.7 11.6 46.2 Amortization of intangible assets 3.2 2.7 1.7 4.9 12.5 Special charges for workforce reductions and advisory costs — 0.6 0.6 0.2 1.4 Gains on sales of assets (0.3 ) (0.4 ) (0.3 ) (0.2 ) (1.2 ) Operating loss (10.5 ) (14.6 ) (36.7 ) 0.1 (61.7 ) Gain on early extinguishment of debt and debt restructuring costs — (16.7 ) — 3.7 (13.0 ) Interest expense 5.0 5.1 4.7 4.9 19.7 Investment income (0.3 ) (0.1 ) (0.1 ) (0.3 ) (0.8 ) Provision (benefit) for income taxes (0.6 ) — — — (0.6 ) Net loss $ (14.6 ) $ (2.9 ) $ (41.3 ) $ (8.2 ) $ (67.0 ) Net loss per share - basic and diluted $ (1.60 ) $ (0.32 ) $ (4.54 ) $ (0.90 ) $ (7.36 ) 2015 1st Qtr. 2nd Qtr. 3rd Qtr. 4th Qtr. Year Revenue $ 167.8 $ 63.3 $ 29.2 $ 157.9 $ 418.2 Cost of sales 160.9 59.0 53.6 75.8 349.3 Gross profit (loss) 6.9 4.3 (24.4 ) 82.1 68.9 Advanced technology license and decommissioning costs 1.8 4.0 1.9 25.3 33.0 Selling, general and administrative 12.3 6.3 13.5 10.5 42.6 Amortization of intangible assets 4.0 2.0 1.1 6.3 13.4 Impairment of excess reorganization value — — — 137.2 137.2 Special charges for workforce reductions 0.6 2.9 9.8 (0.1 ) 13.2 Gains on sales of assets (0.8 ) (0.7 ) (0.3 ) (0.3 ) (2.1 ) Operating loss (11.0 ) (10.2 ) (50.4 ) (96.8 ) (168.4 ) Interest expense 4.9 4.9 4.8 5.0 19.6 Investment income (0.2 ) — (0.1 ) — (0.3 ) Provision (benefit) for income taxes (0.3 ) — — — (0.3 ) Net loss $ (15.4 ) $ (15.1 ) $ (55.1 ) $ (101.8 ) $ (187.4 ) Net loss per share - basic and diluted $ (1.71 ) $ (1.68 ) $ (6.05 ) $ (11.19 ) $ (20.82 ) The calculation of net loss per share on a dilutive basis is provided in Note 14, Net Loss Per Share . No dilutive effect is recognized in periods in which a net loss has occurred or in which the assumed conversion effect of convertible securities is antidilutive.

Summary of Significant Accoun28

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Summary of Significant Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation and Principles of Consolidation The consolidated financial statements of Centrus Energy Corp. (“Centrus” or the “Company”) were prepared in conformity with generally accepted accounting principles in the U.S. (“U.S. GAAP”). Certain prior year amounts have been reclassified to conform to the current presentation. The consolidated financial statements include the accounts of Centrus, its principal subsidiary United States Enrichment Corporation (“Enrichment Corp.”), and its other subsidiaries. All material intercompany transactions are eliminated.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect reported amounts presented and disclosed in the consolidated financial statements. Significant estimates and judgments include, but are not limited to, asset valuations, American Centrifuge decontamination and decommissioning obligations, pension and postretirement health and life benefit costs and obligations, the tax bases of assets and liabilities, the future recoverability of deferred tax assets, and determination of the valuation allowance for deferred tax assets. Actual results may differ from such estimates, and estimates may change if the underlying conditions or assumptions change.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents Cash and cash equivalents include short-term or highly liquid assets with original maturities of three months or less.
Inventory, Policy [Policy Text Block]	Inventories and Inventories Owed to Customers and Suppliers 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 U 235 and depleted uranium having a lower percentage of U 235 . 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 or “feed” component. SWU and uranium inventory costs are determined using the monthly moving average cost method. SWU and uranium purchase costs include shipping costs when applicable. Inventories of SWU and uranium are valued at the lower of cost or net realizable value (“NRV”). NRV is the estimated selling price in the ordinary course of business less reasonably predictable costs of completion, disposal, and transportation. The estimated selling price for SWU and uranium is based on the pricing terms of contracts in the Company’s sales order book, and, for uranium not under contract, the estimated selling price is based primarily on published price indicators at the balance sheet date. 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 Centrus and domestic fabricators, fabricators order quantities of LEU from Centrus based on scheduled or anticipated orders from utility customers for deliveries in future periods. As delivery obligations under actual customer orders arise, Centrus satisfies these obligations by arranging for the transfer to the customer of title to the specified quantity of LEU at the fabricator. Centrus’ balances of SWU and uranium vary over time based on the timing and size of the fabricator’s LEU orders from Centrus 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 Centrus than Centrus is required to deliver to its customers at the fabricator, the fabricator will use these other inventories to satisfy Centrus’ customer order obligations on Centrus’ behalf. In such cases, the transfer of title of LEU from Centrus to the customer results in quantities of SWU and uranium being owed by Centrus to the fabricator. The amounts of SWU and uranium owed to fabricators are satisfied as future deliveries of LEU to fabricators are made.
Income Tax, Policy [Policy Text Block]	Deferred Taxes Centrus follows the asset and liability approach to account for deferred taxes. Deferred tax assets and liabilities are recognized for the anticipated future tax consequences of temporary differences between the balance sheet carrying amounts of assets and liabilities and their respective tax bases. Deferred taxes are based on income tax rates in effect for the years in which temporary differences are expected to reverse. The effect on deferred taxes of a change in income tax rates is recognized in income when the change in rates is enacted in the law. A valuation allowance is provided if it is more likely than not that some or all of the deferred tax assets may not be realized.
Property, Plant and Equipment, Policy [Policy Text Block]	Property, Plant and Equipment Property, plant and equipment are recorded at acquisition cost. Leasehold improvements and machinery and equipment are depreciated on a straight line basis over the shorter of the useful life of the assets or the lease term, if applicable. Refer also to Carrying Value of Long-Lived Assets below.
Intangible Assets, Policy [Policy Text Block]	Intangible Assets Centrus has intangible assets resulting from fresh start accounting as a result of emergence from Chapter 11 bankruptcy on September 30, 2014. The identifiable intangible assets relate to the sales order book and customer relationships. The order book intangible asset is amortized as the order book valued at emergence is reduced, principally as result of deliveries to customers. The customer relationships intangible asset is amortized using the straight-line method over the estimated average useful life of 15 years. Refer also to Carrying Value of Long-Lived Assets below. The excess of the reorganization value over the fair value of identified tangible and intangible assets resulted in a nonamortizing intangible asset as of September 30, 2014. The excess reorganization value (or “goodwill”, as defined by the accounting standards) was tested for impairment and was determined to be fully impaired as of October 1, 2015. Therefore, the Company recorded an impairment charge in the fourth quarter of 2015.
Carrying Value of Long-Lived Assets, Policy [Policy Text Block]	Carrying Value of Long-Lived Assets The carrying values of property, plant and equipment and identifiable intangible assets are subject to impairment tests whenever adverse conditions or changes in circumstances indicate a possible impairment loss. Impairment tests are based on a comparison of estimated future cash flows to the carrying value of long-lived assets. If impairment is indicated, the asset carrying value is reduced to its fair value and an impairment loss is recognized.
Fair Value of Financial Instruments, Policy [Policy Text Block]	Financial Instruments and Fair Value Measurement Accounting standards define fair value as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required or permitted to be recorded at fair value, consideration is given to the principal or most advantageous market and assumptions that market participants would use when pricing the asset or liability. Pursuant to accounting standards, Centrus’ paid-in-kind toggle notes are recorded at face value and the fair value is disclosed. The estimated fair value of the paid-in-kind toggle notes is based on the most recent trading price as of the balance sheet date. Debt issuance costs are deferred and amortized over the life of the instrument. The balance sheet carrying amounts for accounts receivable, accounts payable and accrued liabilities, and payables under SWU purchase agreements approximate fair value because of the short-term nature of the instruments.
Revenue Recognition, Policy [Policy Text Block]	SWU and Uranium Revenue Revenue is derived from sales of the SWU component of LEU, from sales of both the SWU and uranium components of LEU, and from sales of uranium. Revenue is recognized at the time LEU or uranium is delivered under the terms of contracts with domestic and international electric utility customers. Most customers take title and delivery of LEU at fuel fabricators. Centrus ships LEU to nuclear fuel fabricators for scheduled or anticipated orders from utility customers. Based on customer orders, Centrus arranges for the transfer of title of LEU from Centrus to the customer for the specified quantity of LEU at the fuel fabricator. Revenue is recognized when delivery of LEU to the customer occurs at the fuel fabricator. In a limited number of sales transactions, title to uranium or LEU is transferred to the customer without Centrus physically delivering the uranium or LEU to the customer. In such cases, risk of loss remains with Centrus until physical delivery occurs. At the time transfer of title occurs, a performance obligation for Centrus is created and a receivable is recorded. Cash is collected for the receivable under normal credit terms. The recognition of revenue and related cost of sales occurs at the time physical delivery occurs and risk of loss transfers to the customer. On occasion, Centrus will accept payment in the form of uranium. Revenue from the sale of SWU under such contracts is recognized at the time LEU is delivered and is based on the fair value of the uranium received in exchange for the SWU. Contract Services Revenue The contract services segment consists primarily of revenue and cost of sales for engineering and testing work Centrus performs under an agreement with UT-Battelle, LLC (“UT-Battelle”), the management and operating contractor for Oak Ridge National Laboratory (“ORNL”). The contract services segment also includes limited services provided by Centrus to the U.S. Department of Energy (“DOE”) and its contractors at the Portsmouth site related to facilities the Company leases from DOE. Contract services revenue includes billings for fees and payments for allowable costs that are determined in accordance with the terms of the underlying contracts. The contract with UT-Battelle provides for fixed payments for monthly reports. Revenue is recognized as work is performed and as fees are earned. The Company’s spending levels for the UT-Battelle contract work are consistent with the fixed funding levels. The Company’s costs in support of receiving payment under the UT-Battelle contract consist of allowable costs under government cost accounting standards (“CAS”). Allowable costs include direct costs as well as allocations of indirect plant and corporate overhead costs determined in accordance with CAS. Allowable costs are subject to audit by the Defense Contract Audit Agency (“DCAA”), or such other entity that DOE authorizes to conduct the audit. Centrus and DOE have yet to fully settle the Company’s claims for reimbursements for allowable costs related to past contract work performed at the Portsmouth and Paducah sites. The final settlement is subject to Federal Acquisition Regulations requiring the DOE contracting officer to conduct negotiations and prepare a written indirect cost agreement. Revenue resulting from final billing rates is recognized upon completion of the government audits and notice by DOE authorizing final billing. DOE historically has not approved Centrus’ provisional billing rates and has not completed audits of Centrus’ incurred cost submissions and authorized final payments in a timely manner. Additional details are provided in Note 4, Receivables . There is the potential for additional revenue to be recognized, based on the outcome of DOE reviews and audits, as the result of the release of previously established receivable related reserves. However, since these periods have not been finalized with DOE, uncertainty exists and Centrus has not yet recognized this additional revenue.
Advanced Technology Costs, Policy [Policy Text Block]	Advanced Technology License and Decommissioning Costs American Centrifuge expenses that are outside of our contracts with UT-Battelle are included in Advanced Technology License and Decommissioning Costs , including ongoing costs to maintain the demobilized Piketon facility and our licenses from the U.S. Nuclear Regulatory Commission (“NRC”) at that location. In the second quarter of 2016, the Company commenced with the decontamination and decommissioning (“D&D”) of the Piketon facility in accordance with the requirements of the NRC and DOE. Refer to Note 3, Contract Services and Advanced Technology License and Decommissioning Costs, and Note 16, Commitments and Contingencies, for further details regarding the American Centrifuge project.
Pension and Other Postretirement Plans, Policy [Policy Text Block]	Pension and Postretirement Health and Life Benefit Plans The Company provides retirement benefits to certain employees and retirees under defined benefit pension plans and postretirement health and life benefit plans. The valuation of benefit obligations and costs is based on provisions of the plans and actuarial assumptions that involve judgments and estimates. Plan assets and benefit obligations are remeasured each year as of the balance sheet date, or when lump-sum payments exceed certain levels, resulting in differences between actual and projected results. The Company has elected to recognize these actuarial gains and losses immediately in the statement of operations to provide transparency regarding the impacts of changes in plan assets and benefit obligations.
Share-based Compensation, Policy [Policy Text Block]	Stock-Based Compensation Centrus has a stock-based compensation plan which authorizes the issuance of common stock to the Company’s employees, officers, directors and other individuals providing services to the Company or its affiliates pursuant to options, stock appreciation rights, restricted stock units, restricted stock, performance awards, dividend equivalent rights and other stock based awards. Stock-based compensation cost is measured at the grant date based on the fair value of the award. The cost is recognized over the requisite service period on a straight-line basis over the vesting period.
New Accounting Pronouncements, Policy [Policy Text Block]	New Accounting Standards In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers (Topic 606) . ASU 2014-09 introduces a new five-step revenue recognition model in which an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also requires disclosures sufficient to enable users to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers, including qualitative and quantitative disclosures about contracts with customers, significant judgments and changes in judgments, and assets recognized from the costs to obtain or fulfill a contract. The FASB issued amendments in 2015 and 2016 that provide clarification on a number of specific issues as well as requiring additional disclosures. The revenue recognition standard will become effective for the Company beginning with the first quarter of 2018. The Company is evaluating the effect that the provisions of ASU 2014-09 will have on its consolidated financial statements. In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements - Going Concern (Subtopic 205-40) , which requires an evaluation of whether there is substantial doubt about a company’s ability to continue as a going concern and provide certain disclosures depending on the result of such evaluation. For each reporting period, management will be required to evaluate whether there are conditions or events that raise substantial doubt about a company’s ability to continue as a going concern within one year from the date the financial statements are issued. If management identifies such conditions or events, ASU 2014-15 requires disclosures in the notes to the financial statements that outline whether or not there are any plans intended to mitigate the relevant conditions or events to alleviate the substantial doubt. ASU 2014-15 was effective for the Company beginning in the fourth quarter of 2016. The adoption of ASU 2014-15 did not have a material impact on the Company’s consolidated financial statements. In April 2015, the FASB issued ASU 2015-03, Interest - Imputation of Interest (Subtopic 835-30), requiring the presentation of debt issuance costs in the balance sheet as a reduction in the carrying amount of the related debt liability instead of a deferred charge asset. Centrus adopted ASU 2015-03 with retrospective application beginning with the first quarter of 2016. The reclassification of debt issuance costs did not have a material impact on Centrus’ consolidated financial statements. Refer to Note 9, Debt , for details. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842), which requires lessees to recognize a right-of-use asset and lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting expense recognition in the statement of operations. ASU 2016-02 is effective for the Company in the first quarter of 2019, with early adoption permitted, and is to be applied using a modified retrospective approach. The Company is evaluating the effect that the provisions of ASU 2016-02 will have on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, Stock Compensation - Improvements to Employee Share-Based Payment Accounting (Topic 718) . ASU 2016-09 simplifies several aspects of the accounting for share-based payment transactions, including income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. ASU 2016-09 is effective for the Company beginning in the first quarter of 2017. Under ASU 2016-09, entities are permitted to make an accounting policy election to either estimate forfeitures on share-based payment awards, as previously required, or to recognize forfeitures as they occur. The Company has elected to recognize forfeitures as they occur. The provisions of ASU 2016-09 are not expected to have a material impact on the Company’s consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments . ASU 2016-15 addresses the presentation and classification of certain cash receipts and cash payments in the statement of cash flows. It is intended to reduce diversity in practice by providing guidance on eight specific cash flow issues. ASU 2016-15 is effective for the Company beginning in the first quarter of 2018, with early adoption permitted, and is to be applied using a retrospective approach. The provisions of ASU 2016-15 are not expected to have a material impact on the Company’s consolidated financial statements. In October 2016, the FASB issued ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory, requiring an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. ASU 2016-09 is effective for the Company beginning in the first quarter of 2018. Early adoption is permitted. The provisions of ASU 2016-16 are not expected to have a material impact on the Company’s consolidated financial statements. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash . ASU 2016-18 requires that the statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. ASU 2016-18 is to be applied retrospectively for each period presented, and is effective for the Company beginning in the first quarter of 2018. Early adoption is permitted. The provisions of ASU 2016-18 are not expected to have a material impact on the Company’s consolidated financial statements.

Special Charges Special Charges

Special Charges Special Charges (Tables)	12 Months Ended
	Dec. 31, 2016
Restructuring and Related Activities [Abstract]
Special Charges Summary [Table Text Block]	A summary of termination benefit activity and related liabilities follows (in millions): Liability Dec. 31, 2014 2015 Liability Dec. 31, 2015 2016 Liability Dec. 31, 2016 Special Charges Paid Special Charges Paid Workforce reductions: Enrichment cessation and evolving business needs $ 2.4 $ 4.5 (a) $ (6.6 ) (a) $ 0.3 $ 0.3 $ (0.5 ) $ 0.1 Piketon demonstration facility — 8.7 (0.3 ) 8.4 0.1 (3.1 ) 5.4 (b) $ 2.4 $ 13.2 $ (6.9 ) $ 8.7 $ 0.4 $ (3.6 ) $ 5.5 (a) Net of $0.4 million billed to and paid by DOE. (b) Includes $2.1 million included in long-term liabilities.

Accounts Receivable (Tables)

Accounts Receivable (Tables)	12 Months Ended
	Dec. 31, 2016
Accounts Receivable, Net, Current [Abstract]
Schedule of Accounts Receivable	December 31, 2016 2015 (millions) Utility customers and other $ 15.3 $ 24.7 Contract services, primarily DOE 4.6 1.8 Accounts receivable, net $ 19.9 $ 26.5

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2016
Inventory, Net [Abstract]
Schedule of Inventories	Components of inventories follow (in millions): December 31, 2016 December 31, 2015 Current Assets Current Liabilities (a) Inventories, Net Current Assets Current Liabilities (a) Inventories, Net Separative work units $ 115.8 $ 15.2 $ 100.6 $ 221.5 $ 33.1 $ 188.4 Uranium 61.4 42.3 19.1 97.5 73.7 23.8 Materials and supplies 0.2 — 0.2 0.2 — 0.2 $ 177.4 $ 57.5 $ 119.9 $ 319.2 $ 106.8 $ 212.4 (a) Inventories owed to customers and suppliers, included in current liabilities, consist primarily of SWU and uranium inventories owed to fabricators that process LEU into fuel for use in nuclear reactors.

Property, Plant and Equipment32

Property, Plant and Equipment Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	A summary of changes in property, plant and equipment follows (in millions): December 31, Additions / (Depreciation) Retirements December 31, Land $ 1.2 $ — $ — $ 1.2 Leasehold improvements 0.9 2.3 (0.2 ) 3.0 Machinery and equipment 1.6 0.1 — 1.7 Other 0.3 0.6 — 0.9 Property, plant and equipment, gross 4.0 3.0 (0.2 ) 6.8 Accumulated depreciation (0.5 ) (0.5 ) 0.2 (0.8 ) Property, plant and equipment, net $ 3.5 $ 2.5 $ — $ 6.0

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets and Excess Reorganization Value [Table Text Block]	Identifiable intangible assets consist of the following (in millions): December 31, 2016 December 31, 2015 Gross Carrying Amount Accumulated Amortization Net Amount Gross Carrying Amount Accumulated Amortization Net Amount Sales order book $ 54.6 $ 19.9 $ 34.7 $ 54.6 $ 12.0 $ 42.6 Customer relationships 68.9 10.3 58.6 68.9 5.7 63.2 $ 123.5 $ 30.2 $ 93.3 $ 123.5 $ 17.7 $ 105.8
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	The amount of amortization expense for intangible assets in each of the succeeding years is estimated to be as follows (in millions): 2017 $ 10.6 2018 8.9 2019 8.6 2020 9.7 2021 8.6 Thereafter 46.9 $ 93.3

Accounts Payable and Accrued 34

Accounts Payable and Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2016
Accounts Payable and Accrued Liabilities [Abstract]
Schedule of Accounts Payable and Accrued Liabilities [Table Text Block]	December 31, ($ millions) 2016 2015 Trade payables $ 11.5 $ 5.4 Compensation and employee benefits 12.5 19.2 Postretirement health and life benefit obligations - current 13.8 5.3 Severance 3.4 8.7 Other accrued liabilities 5.2 6.2 $ 46.4 $ 44.8

Debt Schedule of Debt (Tables)

Debt Schedule of Debt (Tables)	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Schedule of Debt [Table Text Block]	A summary of long-term debt follows (in millions): 8% Paid-in-Kind Toggle Notes Deferred Issuance Costs Total Long-Term Debt December 31, 2014 $ 240.4 $ (0.7 ) $ 239.7 PIK Interest 7.2 — 7.2 Amortization — 0.1 0.1 December 31, 2015 $ 247.6 $ (0.6 ) $ 247.0 PIK Interest 13.1 — 13.1 Repurchases (26.1 ) — (26.1 ) Amortization/Repurchases — 0.1 0.1 December 31, 2016 $ 234.6 $ (0.5 ) $ 234.1

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Schedule of Financial Instruments Recorded at Fair Value	Financial Instruments Recorded at Fair Value (in Millions) December 31, 2016 December 31, 2015 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets: Cash and cash equivalents $ 260.7 $ — $ — $ 260.7 $ 234.0 $ — $ — $ 234.0 Deferred compensation asset (a) 1.1 — — 1.1 — 1.5 — 1.5 Liabilities: Deferred compensation obligation (a) 1.1 — — 1.1 — 1.4 — 1.4 (a)

Pension and Postretirement He37

Pension and Postretirement Health and Life Benefits (Tables)	12 Months Ended
	Dec. 31, 2016
General Discussion of Pension and Other Postretirement Benefits [Abstract]
Schedule of Changes in Projected Benefit Obligations [Table Text Block]	Changes in the projected benefit obligations and plan assets and the funded status of the plans follow (in millions): Defined Benefit Pension Plans Postretirement Health and Life Benefit Plans Year Ended December 31, Year Ended December 31, 2016 2015 2016 2015 Changes in Benefit Obligations: Obligations at beginning of period $ 832.8 $ 961.4 $ 203.5 $ 237.7 Actuarial (gains) losses, net 19.1 (55.2 ) (9.2 ) (30.2 ) Service costs 3.8 5.8 — 0.2 Interest costs 35.4 36.9 8.2 8.8 Benefits paid (60.9 ) (62.1 ) (13.3 ) (13.1 ) Lump sum benefits paid (12.2 ) (50.6 ) — — Less federal subsidy on benefits paid — — — 0.1 Plan change — — 3.6 — Administrative expenses paid (3.4 ) (3.4 ) — — Obligations at end of period 814.6 832.8 192.8 203.5 Changes in Plan Assets: Fair value of plan assets at beginning of period 656.3 772.4 13.8 26.3 Actual return on plan assets 50.2 (8.0 ) 0.5 0.4 Company contributions 4.1 8.0 6.7 0.2 Benefits paid (60.9 ) (62.1 ) (13.3 ) (13.1 ) Lump sum benefits paid (12.2 ) (50.6 ) — — Administrative expenses paid (3.4 ) (3.4 ) — — Fair value of plan assets at end of period 634.1 656.3 7.7 13.8 (Unfunded) status at end of period (180.5 ) (176.5 ) (185.1 ) (189.7 ) Amounts recognized in assets and liabilities: Current liabilities $ (0.6 ) $ (4.2 ) (13.8 ) (5.4 ) Noncurrent liabilities (179.9 ) (172.3 ) (171.3 ) (184.3 ) $ (180.5 ) $ (176.5 ) $ (185.1 ) $ (189.7 ) Amounts in accumulated other comprehensive income (loss), pre-tax: Prior service cost (credit) $ — $ — $ (2.6 ) $ (6.6 ) Discount rate used to determine benefit obligations at end of period: 4.1% 4.5% 3.9% 4.2%
Schedule of Net Benefit Costs [Table Text Block]	Components of Net Periodic Benefit Costs and Other Amounts Recognized in Other Comprehensive Loss (in millions) Defined Benefit Pension Plans Postretirement Health and Life Benefit Plans Year Ended December 31, Year Ended December 31, 2016 2015 2016 2015 Net Periodic Benefit Costs Service costs $ 3.8 $ 5.8 $ — $ 0.2 Interest costs 35.4 36.9 8.2 8.8 Expected return on plan assets (gains) (42.0 ) (47.4 ) (0.3 ) (0.8 ) Actuarial (gains) losses, net 10.9 0.2 (9.5 ) (29.8 ) Amortization of prior service costs (credits), net — — (0.3 ) (0.3 ) Net periodic benefit costs (credits) $ 8.1 $ (4.5 ) $ (1.9 ) $ (21.9 ) Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss) Net prior service costs (credits) — — 3.6 — Amortization of prior service (costs) credits, net — — 0.3 0.3 Total (gain) loss recognized in other comprehensive income (loss), pre-tax $ — $ — $ 3.9 $ 0.3 Total recognized in net periodic benefit costs (income) and other comprehensive income (loss), pre-tax $ 8.1 $ (4.5 ) $ 2.0 $ (21.6 )
Schedule of Assumptions Used [Table Text Block]	Defined Benefit Pension Plans Postretirement Health and Life Benefit Plans Year Ended December 31, Year Ended December 31, 2016 2015 2016 2015 Assumptions used to determine net periodic benefit costs: Discount rate 4.1% 4.5% 3.9% 4.2% Expected return on plan assets 6.8% 6.8% 5.0% 5.3%
Schedule of Health Care Cost Trend Rates [Table Text Block]	Healthcare cost trend rates used to measure postretirement health benefit obligations follow: December 31, 2016 2015 Healthcare cost trend rate for the following year 7% 7.5% Long-term rate that the healthcare cost trend rate gradually declines to 5% 5% Year that the healthcare cost trend rate is expected to reach the long-term rate 2021 2021
Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates [Table Text Block]	A one-percentage-point change in the assumed healthcare cost trend rates would have an effect on the postretirement health benefit obligation and costs of the Successor Company, as follows (in millions): One Percentage Point Increase Decrease Postretirement health benefit obligation $ 4.0 $ (3.8 ) Net periodic benefit costs (service and interest cost components only) $ 0.3 $ (0.3 )
Schedule of Allocation of Plan Assets [Table Text Block]	The allocation of plan assets between equity and debt securities and the target allocation range by asset category follows: December 31, 2016 2015 2017 Target Defined Benefit Pension Plans: Equity securities 41 % 47 % 40 - 60% Debt securities 59 53 40 - 60 100 % 100 % Postretirement Health and Life Benefit Plans: Equity securities 100 % 64 % 85 - 100% Debt securities 0 36 0 - 15 100 % 100 % Plan assets are measured at fair value. Following are the plan investments as of December 31, 2016, and December 31, 2015, categorized by the fair value hierarchy levels described in Note 10, Fair Value Measurements, (in millions): Defined Benefit Pension Plans Level 1 Level 2 Level 3 Total 2016 2015 2016 2015 2016 2015 2016 2015 U.S. government securities $ — $ — $ 84.7 $ 61.8 $ — $ — $ 84.7 $ 61.8 Corporate debt — — 217.0 206.9 — — 217.0 206.9 Municipal bonds — — 6.2 6.8 — — 6.2 6.8 Mortgage and asset backed securities — — 5.4 — — — 5.4 — Fair value of investments by hierarchy level $ — $ — $ 313.3 $ 275.5 $ — $ — $ 313.3 $ 275.5 Investments measured at NAV (a) 318.3 377.2 Accrued interest receivable 3.5 3.5 Unsettled transactions (1.0 ) 0.1 Plan assets $ 634.1 $ 656.3 Postretirement Health and Life Benefit Plans Level 1 Level 2 Level 3 Total 2016 2015 2016 2015 2016 2015 2016 2015 Money market funds $ 0.2 $ 1.0 $ — $ — $ — $ — $ 0.2 $ 1.0 Bond mutual funds 7.5 4.0 — — — — 7.5 4.0 Equity mutual funds — 8.8 — — — — — 8.8 Fair value of investments by hierarchy level $ 7.7 $ 13.8 $ — $ — $ — $ — $ 7.7 $ 13.8 (a) Equity, bond and money market investments held in collective trusts are valued based on the net asset value (“NAV”) provided by the administrator of the funds. The NAV for each fund is based on the underlying assets owned by the fund, less any expenses accrued against the fund, divided by the number of fund shares outstanding. While the underlying investments are traded on an exchange, the funds are not. Fair values for the collective trust investments are measured using the NAVs as a practical expedient and are not categorized in the fair value hierarchy.
Schedule of Expected Benefit Payments [Table Text Block]	Estimated future benefit plan payments follow (in millions): Defined Benefit Pension Plans Postretirement Health and Life Benefit Plans 2017 $ 60.4 $ 21.5 2018 59.4 20.4 2019 58.0 19.0 2020 56.1 17.2 2021 55.0 15.8 2022 to 2026 258.9 61.3

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2016
Share-based Compensation [Abstract]
Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]	A summary of stock-based compensation costs follows (in millions): Year Ended December 31, 2016 2015 Total stock-based compensation costs: Restricted stock units $ 0.2 $ 0.2 Stock options 0.3 0.2 Expense included in selling, general and administrative expense $ 0.5 $ 0.4 Total recognized tax benefit $ — $ —
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	Assumptions used in the Black-Scholes option pricing model to value option grants follow: Year Ended December 31, 2016 2015 Risk-free interest rate 1.91% 1.91% Expected volatility 75% 75% Expected option life (years) 6 6 Weighted-average grant date fair value $1.77 $2.62 Options granted (in thousands) 15 437
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]	Stock options vest and become exercisable in equal annual installments over a three or four year period and expire ten years from the date of grant. A summary of stock option activity follows: Stock Options (thousands) Weighted Average Exercise Price Weighted Average Remaining Contractual Life in Years Aggregate Intrinsic Value (millions) Outstanding at December 31, 2015 475 $4.09 9.3 $— Granted 15 $2.68 Exercised — — Forfeited/Cancelled (7) $5.62 Outstanding at December 31, 2016 483 $4.02 8.4 $1.1 Exercisable at December 31, 2016 141 $4.12 8.3 $0.3
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]	Stock options outstanding and options exercisable at December 31, 2016, follow: Stock Exercise Price Options Outstanding (thousands) Weighted Average Remaining Contractual Life in Years Options Exercisable (thousands) $5.62 30 7.9 20.0 $4.37 300 8.2 75.0 $3.90 23 8.6 8.0 $3.93 15 8.6 5.0 $2.71 50 8.8 16.0 $2.75 50 8.8 17.0 $2.68 15 9.5 —

Income Taxes Income Taxes (Tabl

Income Taxes Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	The provision (benefit) for income taxes from continuing operations is as follows (in millions): Year Ended December 31, 2016 2015 Current: Federal $ — $ — State and local (0.6 ) (0.3 ) Foreign — — (0.6 ) (0.3 ) Deferred: Federal — — State and local — — Foreign — — — — $ (0.6 ) $ (0.3 )
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	Future tax consequences of temporary differences between the carrying amounts for financial reporting purposes and the Company’s estimate of the tax bases of its assets and liabilities result in deferred tax assets and liabilities, as follows (in millions): December 31, 2016 2015 Deferred tax assets: Employee benefits costs $ 139.3 $ 140.8 Inventory — 3.1 Property, plant and equipment 318.8 437.1 Net operating loss and credit carryforwards 254.9 114.3 Accrued expenses 14.9 9.1 Other 12.6 11.9 740.5 716.3 Valuation allowance (702.2 ) (676.4 ) Deferred tax assets, net of valuation allowance $ 38.3 $ 39.9 Deferred tax liabilities: Inventory $ 2.6 $ — Intangible assets 33.0 37.3 Prepaid expenses 2.7 2.6 Deferred tax liabilities $ 38.3 $ 39.9 $ — $ —
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	A reconciliation of income taxes calculated based on the federal statutory income tax rate of 35% and the effective tax rate follows: Year Ended December 31, 2016 2015 Federal statutory tax rate 35 % 35 % Gain on early extinguishment of debt 6 — Excess reorganization value — (26 ) Interest expense (3 ) (1 ) Valuation allowance against deferred tax assets (36 ) (9 ) State rate changes and tax attributes (1 ) 1 1 % — %
Summary of Income Tax Contingencies [Table Text Block]	A reconciliation of the beginning and ending amount of unrecognized tax benefits follows (in millions): Year Ended December 31, 2016 2015 Balance at beginning of the period $ 1.0 $ 1.3 Additions to tax positions of current period — — Reductions to tax positions of prior years (0.6 ) (0.3 ) Balance at end of the period $ 0.4 $ 1.0

Net Income Per Share (Tables)

Net Income Per Share (Tables)	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Schedule of Net Income Per Share	Year Ended December 31, (in millions, except per share amounts) 2016 2015 Numerator for basic and diluted calculation: Net loss $ (67.0 ) $ (187.4 ) Denominator: Weighted average common shares 9.1 9.0 Denominator for basic calculation 9.1 9.0 Weighted average effect of dilutive securities: Stock compensation awards (a) — — Denominator for diluted calculation 9.1 9.0 Net loss per share - basic and diluted $ (7.36 ) $ (20.82 )
Schedule of Securities Excluded from Net Income Per Share	Year Ended December 31, 2016 2015 Options excluded from diluted net income per share 368,000 375,000 Exercise price of excluded options $ 3.90 to $ 3.90 to $ 5.62 $ 5.62

Commitments and Contingencies C

Commitments and Contingencies Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Future estimated minimum lease payments and expected lease administration payments follow (in millions): 2017 $ 3.1 2018 2.4 2019 1.6 2020 0.9 2021 0.9 Thereafter 5.7 $ 14.6

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Segment Reporting Information	Year Ended December 31, (in millions) 2016 2015 Revenue LEU segment: Separative work units $ 258.5 $ 289.9 Uranium 14.3 65.5 272.8 355.4 Contract services segment 38.5 62.8 Revenue $ 311.3 $ 418.2 Segment Gross Profit LEU segment $ 38.5 $ 70.1 Contract services segment 6.6 (1.2 ) Gross profit $ 45.1 $ 68.9
Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Table Text Block]	Revenue attributed to domestic and foreign customers, including customers in a foreign country representing 10% or more of total revenue, follows (in millions): Year Ended December 31, 2016 2015 United States $ 242.8 $ 272.8 Foreign: Japan 49.1 77.8 Belgium * 55.5 Other 19.4 12.1 68.5 145.4 Total revenue $ 311.3 $ 418.2 * less than 10%

Quarterly Results of Operatio43

Quarterly Results of Operations (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Results of Operations (Unaudited) [Abstract]
Schedule of Quarterly Financial Information [Table Text Block]	2016 1st Qtr. 2nd Qtr. 3rd Qtr. 4th Qtr. Year Revenue $ 90.0 $ 63.4 $ 21.4 $ 136.5 $ 311.3 Cost of sales 74.2 57.9 23.5 110.6 266.2 Gross profit (loss) 15.8 5.5 (2.1 ) 25.9 45.1 Advanced technology license and decommissioning costs 12.0 4.7 21.9 9.3 47.9 Selling, general and administrative 11.4 12.5 10.7 11.6 46.2 Amortization of intangible assets 3.2 2.7 1.7 4.9 12.5 Special charges for workforce reductions and advisory costs — 0.6 0.6 0.2 1.4 Gains on sales of assets (0.3 ) (0.4 ) (0.3 ) (0.2 ) (1.2 ) Operating loss (10.5 ) (14.6 ) (36.7 ) 0.1 (61.7 ) Gain on early extinguishment of debt and debt restructuring costs — (16.7 ) — 3.7 (13.0 ) Interest expense 5.0 5.1 4.7 4.9 19.7 Investment income (0.3 ) (0.1 ) (0.1 ) (0.3 ) (0.8 ) Provision (benefit) for income taxes (0.6 ) — — — (0.6 ) Net loss $ (14.6 ) $ (2.9 ) $ (41.3 ) $ (8.2 ) $ (67.0 ) Net loss per share - basic and diluted $ (1.60 ) $ (0.32 ) $ (4.54 ) $ (0.90 ) $ (7.36 ) 2015 1st Qtr. 2nd Qtr. 3rd Qtr. 4th Qtr. Year Revenue $ 167.8 $ 63.3 $ 29.2 $ 157.9 $ 418.2 Cost of sales 160.9 59.0 53.6 75.8 349.3 Gross profit (loss) 6.9 4.3 (24.4 ) 82.1 68.9 Advanced technology license and decommissioning costs 1.8 4.0 1.9 25.3 33.0 Selling, general and administrative 12.3 6.3 13.5 10.5 42.6 Amortization of intangible assets 4.0 2.0 1.1 6.3 13.4 Impairment of excess reorganization value — — — 137.2 137.2 Special charges for workforce reductions 0.6 2.9 9.8 (0.1 ) 13.2 Gains on sales of assets (0.8 ) (0.7 ) (0.3 ) (0.3 ) (2.1 ) Operating loss (11.0 ) (10.2 ) (50.4 ) (96.8 ) (168.4 ) Interest expense 4.9 4.9 4.8 5.0 19.6 Investment income (0.2 ) — (0.1 ) — (0.3 ) Provision (benefit) for income taxes (0.3 ) — — — (0.3 ) Net loss $ (15.4 ) $ (15.1 ) $ (55.1 ) $ (101.8 ) $ (187.4 ) Net loss per share - basic and diluted $ (1.71 ) $ (1.68 ) $ (6.05 ) $ (11.19 ) $ (20.82 )

Summary of Significant Accoun44

Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2016
Summary of Significant Accounting Policies [Abstract]
Finite-Lived Intangible Asset, Useful Life	15 years

Special Charges (Schedule of Re

Special Charges (Schedule of Restructuring and Related Costs)(Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Restructuring liability				$ 8.7				$ 2.4	$ 8.7	$ 2.4
Termination benefit costs			$ 0.1			$ 8.7			0.4
Payments for one-time termination benefits									(3.6)	(6.9)
Restructuring liability	$ 5.5				$ 8.7				5.5	8.7
DOE Share of Paducah Termination Benefit Costs										(0.4)
Special charges for workforce reductions	$ 0.2	$ 0.6	$ 0.6	$ 0	$ (0.1)	$ 9.8	$ 2.9	$ 0.6	$ 1.4	$ 13.2

Special Charges (Narrative)(Det

Special Charges (Narrative)(Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Actuarial (gain) loss from remeasurement, net									$ (1.4)	$ 29.6
Termination benefit costs			$ 0.1			$ 8.7			0.4
Other restructuring costs									1
DOE Share of Paducah Termination Benefit Costs										0.4
Payments for Restructuring									(3.6)	(6.9)
Restructuring Reserve	$ 5.5				$ 8.7				5.5	8.7	$ 2.4
Restructuring Reserve, Noncurrent	2.1								2.1
Restructuring Charges	0.2	$ 0.6	$ 0.6	$ 0	(0.1)	$ 9.8	$ 2.9	$ 0.6	1.4	13.2
Contract Termination [Member]
Termination benefit costs									0.1	8.7
Payments for Restructuring									(3.1)	(0.3)
Restructuring Reserve	5.4				8.4				5.4	8.4
Other Restructuring [Member]
Termination benefit costs									0.3	4.5
Payments for Restructuring									(0.5)	(6.6)
Restructuring Reserve	$ 0.1				$ 0.3				$ 0.1	$ 0.3	$ 2.4

Contract Services and Advance47

Contract Services and Advanced Technology License and Decommissioning Costs (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Contract revenue current work		$ 30.4
Contract revenue past work		8.1
D&D Expense		19		$ 7
Decontamination and decommissioning obligations - total		$ 38.6
2017 ORNL Contract [Member] | Scenario, Forecast [Member]
Contract value	$ 25
Contract monthly revenue	2
Contract milestone payments	$ 1
2016 ORNL Contract [Member]
Contract monthly revenue			$ 2.7
2015 ORNL Contract [Member]
Contract monthly revenue					$ 6.9

Accounts Receivable (Schedule o

Accounts Receivable (Schedule of Accounts Receivable) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Accounts Receivable, Net, Current [Abstract]
Utility Customer Receivables	$ 15.3	$ 24.7
Contract Services Customer Receivables	4.6	1.8
Accounts Receivable, Net	$ 19.9	$ 26.5

Accounts Receivable (Narrative)

Accounts Receivable (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Noncurrent			$ 38
Other long-term liabilities	$ 31.9	$ 38.6
Government [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Noncurrent		78
Accounts Receivable, Net, Noncurrent		22.8
Other long-term liabilities	19.4	19.3
Proceeds on claims		6.7
Government - portion related to retiree benefits [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Noncurrent		42.8
Corporation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Noncurrent		$ 3.8
Proceeds on claims	$ 0.4

Inventories (Schedule of Invent

Inventories (Schedule of Inventories) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Inventory, Net [Abstract]
Separative work units inventory	$ 115.8	$ 221.5
Uranium inventory	61.4	97.5
Materials and supplies	0.2	0.2
Inventories	177.4	319.2
Separative work units owed to customers and suppliers	15.2	33.1
Uranium owed to customers and suppliers	42.3	73.7
Inventories owed to customers and suppliers	57.5	106.8
Separative work units net of liability	100.6	188.4
Uranium inventory net of liability	19.1	23.8
Inventories, net	$ 119.9	$ 212.4

Inventories (Narrative) (Detail

Inventories (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Inventory, Net [Abstract]
Nonmonetary transaction, amount of barter transaction	$ 8.3

Property, Plant and Equipment52

Property, Plant and Equipment Property, Plant and Equipment (Tables) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 6.8	$ 4
Property, Plant and Equipment, Additions	3
Property, Plant and Equipment, Disposals	(0.2)
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(0.8)	(0.5)
Depreciation	(0.5)
Accumulated Depreciation, Depletion and Amortization, Sale or Disposal of Property, Plant and Equipment	0.2
Property, Plant And Equipment, Net Capital Expenditures	2.5
Property, Plant and Equipment, Net	6	3.5
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1.2	1.2
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	3	0.9
Property, Plant and Equipment, Additions	2.3
Property, Plant and Equipment, Disposals	(0.2)
Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1.7	1.6
Property, Plant and Equipment, Additions	0.1
Other Capitalized Property Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	0.9	$ 0.3
Property, Plant and Equipment, Additions	$ 0.6

Property, Plant and Equipment53

Property, Plant and Equipment Property, Plant and Equipment (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Property, Plant and Equipment [Abstract]
Payments for Tenant Improvements	$ 1.7

Intangible Assets Schedule of I

Intangible Assets Schedule of Intangible Assets and Excess Reorganization Value (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2014
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	$ 123.5	$ 123.5
Accumulated intangible asset amortization	(30.2)	(17.7)
Amortizable intangible assets, net	93.3	105.8
Excess reorganization value			$ 137.2
Impairment of excess reorganization value	$ 0	(137.2)
Average useful life of finite-lived intangible assets	15 years
Contract-Based Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	$ 54.6	54.6
Accumulated intangible asset amortization	(19.9)	(12)
Amortizable intangible assets, net	34.7	42.6
Customer-Related Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	68.9	68.9
Accumulated intangible asset amortization	(10.3)	(5.7)
Amortizable intangible assets, net	$ 58.6	$ 63.2

Intangible Assets Finite-Lived

Intangible Assets Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity (Details) $ in Millions	Dec. 31, 2016USD ($)
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	$ 10.6
Finite-Lived Intangible Assets, Amortization Expense, Year Two	8.9
Finite-Lived Intangible Assets, Amortization Expense, Year Three	8.6
Finite-Lived Intangible Assets, Amortization Expense, Year Four	9.7
Finite-Lived Intangible Assets, Amortization Expense, Year Five	8.6
Finite-Lived Intangible Assets, Amortization Expense, after Year Five	46.9
Finite-Lived Intangible Assets, Net	$ 93.3

Accounts Payable and Accrued 56

Accounts Payable and Accrued Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Trade payables	$ 11.5	$ 5.4
Compensation and benefits payable	12.5	19.2
Postretirement health and life benefit obligations - current	13.8	5.3
Accrued severance payments	3.4	8.7
Other accrued liabilities	5.2	6.2
Accounts payable and accrued liabilities	$ 46.4	$ 44.8

Debt (Narrative) (Details)

Debt (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Long-term debt, gross		$ 234.6	$ 247.6	$ 240.4
Long-term debt		234.1	$ 247	239.7
Extinguishment of debt, fair value		9.8
Extinguishment of debt		$ 26.1
Debt instrument interest rate		8.00%
Preferred Stock, Par Value Per Share		$ 1	$ 1
Gain on early extinguishment of debt		$ 16.7	$ 0
Write off of deferred financing cost		$ 0.1
Debt Interest Rate, PIK		5.50%	3.00%
Paid-in-Kind Interest		$ 9.7	$ 5.4
Debt issuance costs		0.5	$ 0.6	$ 0.7
Interest payable		4.7
Interest payable, current		1.5
Interest payable, noncurrent		$ 3.2
Scenario, Forecast [Member]
Extinguishment of debt	$ 204.9
Preferred Stock, Shares Outstanding	104,574
Preferred Stock, Par Value Per Share	$ 1,000
Cash paid in exchange	$ 27.6
Gain on early extinguishment of debt	34
Senior Notes [Member] | Scenario, Forecast [Member]
Long-term debt	$ 136
Debt instrument interest rate	8.25%
Senior Notes	$ 74.3
Payment in Kind (PIK) Note [Member] | Scenario, Forecast [Member]
Long-term debt	$ 29.6

Debt Schedule of Debt (Details)

Debt Schedule of Debt (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Long-term debt, gross	$ 234.6	$ 247.6	$ 240.4
Debt increase for paid and accrued PIK interest	13.1	7.2
Extinguishment of debt	(26.1)
Amortization of debt issuance costs	0.1	0.1
Debt issuance costs	(0.5)	(0.6)	(0.7)
Long-term debt	$ 234.1	$ 247	$ 239.7

Fair Value Measurements (Financ

Fair Value Measurements (Financial Instruments Recorded at Fair Value) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Cash and cash equivalents	$ 260.7	$ 234
Deferred compensation asset	1.1	1.5
Deferred compensation obligation	1.1	1.4
Level 1 [Member]
Deferred compensation asset	1.1
Deferred compensation obligation	$ 1.1
Level 2 [Member]
Deferred compensation asset		1.5
Deferred compensation obligation		$ 1.4

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Long-term debt, gross	$ 234.6	$ 247.6	$ 240.4
Long-term debt, fair value	$ 107.4	$ 36.9

Pension and Postretirement He61

Pension and Postretirement Health and Life Benefits (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Actuarial (gain) loss from remeasurement, net		$ (1.4)	$ 29.6
Defined Contribution Plan, Cost Recognized		3
Scenario, Forecast [Member]
Expected defined benefit plan contributions for next fiscal year for qualified plans	$ 1.1
Expected defined benefit plan contributions for next fiscal year for non-qualified plans	0.6
Expected defined benefit plan contributions for next fiscal year for postretirement health and life benefit plans	$ 13.8
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Accumulated Benefit Obligation		814.6	832.8
Defined Benefit Plan, Net Periodic Benefit Cost		$ 8.1	(4.5)
Approximate Number of Plan Participants		5,000
Defined Benefit Plan, Contributions by Employer		$ 4.1	8
Actuarial (gain) loss from remeasurement, net		$ 19.1	$ (55.2)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		4.10%	4.50%
Defined Benefit Plan, Expected Return on Plan Assets		$ 42	$ 47.4
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost		$ (1.9)	(21.9)
Approximate Number of Plan Participants		4,000
Defined Benefit Plan, Contributions by Employer		$ 6.7	0.2
Actuarial (gain) loss from remeasurement, net		$ (9.2)	$ (30.2)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		3.90%	4.20%
Defined Benefit Plan, Expected Return on Plan Assets		$ 0.3	$ 0.8

Pension and Postretirement He62

Pension and Postretirement Health and Life Benefits Pension and Postretirement Health and Life Benefits (Schedule of Changes in Projected Benefit Obligations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2014
Actuarial (gain) loss from remeasurement, net	$ (1.4)	$ 29.6
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Benefit Obligation	814.6	832.8	$ 961.4
Actuarial (gain) loss from remeasurement, net	19.1	(55.2)
Defined Benefit Plan, Service Cost	3.8	5.8
Defined Benefit Plan, Interest Cost	35.4	36.9
Defined Benefit Plan, Benefits Paid	(60.9)	(62.1)
Defined Benefit Plan, Lump Sum Benefits Paid	(12.2)	(50.6)
Defined Benefit Plan, Administrative Expenses Paid	(3.4)	(3.4)
Defined Benefit Plan, Fair Value of Plan Assets	634.1	656.3	772.4
Defined Benefit Plan, Actual Return on Plan Assets	50.2	(8)
Defined Benefit Plan, Contributions by Employer	4.1	8
Defined Benefit Plan, Funded Status of Plan	(180.5)	(176.5)
Amounts Recognized In Current Liabilities	(0.6)	(4.2)
Amounts Recognized In Noncurrent Liabilities	(179.9)	(172.3)
Defined Benefit Plan, Amounts Recognized in Balance Sheet	$ (180.5)	$ (176.5)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.10%	4.50%
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan, Benefit Obligation	$ 192.8	$ 203.5	237.7
Actuarial (gain) loss from remeasurement, net	(9.2)	(30.2)
Defined Benefit Plan, Service Cost	0	0.2
Defined Benefit Plan, Interest Cost	8.2	8.8
Defined Benefit Plan, Benefits Paid	(13.3)	(13.1)
Defined Benefit Plan, Lump Sum Benefits Paid	0	0
Defined Benefit Plan, Gross Prescription Drug Subsidy Receipts Received	0	0.1
Defined Benefit Plan, Plan Amendments	3.6
Defined Benefit Plan, Administrative Expenses Paid	0
Defined Benefit Plan, Fair Value of Plan Assets	7.7	13.8	$ 26.3
Defined Benefit Plan, Actual Return on Plan Assets	0.5	0.4
Defined Benefit Plan, Contributions by Employer	6.7	0.2
Defined Benefit Plan, Funded Status of Plan	(185.1)	(189.7)
Amounts Recognized In Current Liabilities	(13.8)
Amounts Recognized In Noncurrent Liabilities	(171.3)	(184.3)
Defined Benefit Plan, Amounts Recognized in Balance Sheet	(185.1)	(189.7)
Recognized In Accumulated Other Comprehensive Income Pre Tax Prior Service Cost Credit	$ (2.6)	$ (6.6)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	3.90%	4.20%

Pension and Postretirement He63

Pension and Postretirement Health and Life Benefits (Schedule of Net Benefit Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Actuarial (gain) loss from remeasurement, net	$ 1.4	$ (29.6)
Pension Plan, Defined Benefit [Member]
Service costs	3.8	5.8
Interest costs	35.4	36.9
Expected return on plan assets (gains)	(42)	(47.4)
Amortization of actuarial (gains) losses, net	10.9	0.2
Actuarial (gain) loss from remeasurement, net	(19.1)	55.2
Net periodic benefit cost (credit)	8.1	(4.5)
Postretirement Health and Life Benefits Plans [Member]
Service costs	0	0.2
Interest costs	8.2	8.8
Expected return on plan assets (gains)	(0.3)	(0.8)
Amortization of actuarial (gains) losses, net	(9.5)	(29.8)
Actuarial (gain) loss from remeasurement, net	9.2	30.2
Amortization of prior service costs (credits), net	0.3	0.3
Net periodic benefit cost (credit)	$ (1.9)	$ (21.9)

Pension and Postretirement He64

Pension and Postretirement Health and Life Benefits Pension and Postretirement Health and Life Benefits (Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), before Tax	$ (0.3)	$ (0.3)
Pension Plan, Defined Benefit [Member]
Total recognized in net periodic benefit costs (income) and other comprehensive income (loss), pre-tax	8.1	(4.5)
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	3.6
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), before Tax	0.3
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	3.9	0.3
Total recognized in net periodic benefit costs (income) and other comprehensive income (loss), pre-tax	$ 2	$ (21.6)

Pension and Postretirement He65

Pension and Postretirement Health and Life Benefits Pension and Postretirement Health and Life Benefits (Schedule of Assumptions Used) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	4.10%	4.50%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets	6.80%	6.80%
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	3.90%	4.20%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets	5.00%	5.30%

Pension and Postretirement He66

Pension and Postretirement Health and Life Benefits Pension and Postretirement Health and Life Benefits (Schedule of Healthcare Cost Trend Rates) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year	7.00%	7.50%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate	5.00%	5.00%
Defined Benefit Plan, Year that Rate Reaches Ultimate Trend Rate	2,021	2,021

Pension and Postretirement He67

Pension and Postretirement Health and Life Benefits Pension and Postretirement Health and Life Benefits (Schedule of Effect of One Percentage Point Change In Assumed Health Care Cost Trend Rates) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation	$ 4
Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation	(3.8)
Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components	0.3
Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components	$ (0.3)

Pension and Postretirement He68

Pension and Postretirement Health and Life Benefits Pension and Postretirement Health and Life Benefits (Plan Asset Allocations) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	100.00%	100.00%
Pension Plan, Defined Benefit [Member] | Equity Securities [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	41.00%	47.00%
Defined Benefit Plan, Target Plan Asset Allocations Range Minimum	40.00%
Defined Benefit Plan, Target Plan Asset Allocations Range Maximum	60.00%
Pension Plan, Defined Benefit [Member] | Debt Securities [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	59.00%	53.00%
Defined Benefit Plan, Target Plan Asset Allocations Range Minimum	40.00%
Defined Benefit Plan, Target Plan Asset Allocations Range Maximum	60.00%
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	100.00%	100.00%
Other Postretirement Benefit Plan, Defined Benefit [Member] | Equity Securities [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	100.00%	64.00%
Defined Benefit Plan, Target Plan Asset Allocations Range Minimum	85.00%
Defined Benefit Plan, Target Plan Asset Allocations Range Maximum	100.00%
Other Postretirement Benefit Plan, Defined Benefit [Member] | Debt Securities [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	0.00%	36.00%
Defined Benefit Plan, Target Plan Asset Allocations Range Minimum	0.00%
Defined Benefit Plan, Target Plan Asset Allocations Range Maximum	15.00%

Pension and Postretirement He69

Pension and Postretirement Health and Life Benefits Pension and Postretirement Health and Life Benefits (Schedule of Fair Value of Plan Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2014
Pension Plan, Defined Benefit [Member]
US Government Securities	$ 84.7	$ 61.8
Corporate Debt	217	206.9
Municipal Bonds	6.2	6.8
Fair Value of Investments by Hierarchy Level	313.3	275.5
Investments measured at NAV	318.3	377.2
Accrued Interest Receivable	3.5	3.5
Unsettled Transactions Receivable	(1)	0.1
Defined Benefit Plan, Fair Value of Plan Assets	634.1	656.3	$ 772.4
Other Postretirement Benefit Plan, Defined Benefit [Member]
Money Market Funds	0.2	1
Bond Mutual Funds	7.5	4
Equity Mutual Funds	0	8.8
Fair Value of Investments by Hierarchy Level	7.7	13.8
Defined Benefit Plan, Fair Value of Plan Assets	7.7	13.8	$ 26.3
Fair Value, Inputs, Level 1 [Member] | Other Postretirement Benefit Plan, Defined Benefit [Member]
Money Market Funds	0.2	1
Bond Mutual Funds	7.5	4
Equity Mutual Funds	0	8.8
Fair Value of Investments by Hierarchy Level	7.7	13.8
Fair Value, Inputs, Level 2 [Member] | Other Postretirement Benefit Plan, Defined Benefit [Member]
US Government Securities	84.7	61.8
Corporate Debt	217	206.9
Mortgage and asset backed securities	5.4
Municipal Bonds	6.2	6.8
Fair Value of Investments by Hierarchy Level	$ 313.3	$ 275.5

Pension and Postretirement He70

Pension and Postretirement Health and Life Benefits Pension and Postretirement Health and Life Benefits (Schedule of Estimated Future Benefit Payments) (Details) $ in Millions	Dec. 31, 2016USD ($)
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	$ 60.4
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	59.4
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	58
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	56.1
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	55
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	258.9
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	21.5
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	20.4
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	19
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	17.2
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	15.8
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	$ 61.3

Stock-Based Compensation (Narra

Stock-Based Compensation (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2014
Common Stock, Shares Reserved for Future Issuance Under Management Incentive Plan	414,000		1,000,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 0.7
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	1 year 9 months 18 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	15,000	437,000
Employee Stock Option [Member]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 0.7
Restricted Stock Units (RSUs) [Member]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 0

Stock-Based Compensation (Stock

Stock-Based Compensation (Stock-Based Compensation Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation [Abstract]
Restricted Stock or Unit Expense	$ 0.2	$ 0.2
Stock or Unit Option Plan Expense	0.3	0.2
Allocated Share-based Compensation Expense	$ 0.5	$ 0.4

Stock-Based Compensation Stock-

Stock-Based Compensation Stock-Based Compensation (Assumptions Used in the Black-Scholes Option Pricing Model) (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation [Abstract]
Share-based Goods and Nonemployee Services Transaction, Valuation Method, Risk Free Interest Rate	1.91%	1.91%
Share-based Goods and Nonemployee Services Transaction, Valuation Method, Expected Volatility Rate	75.00%	75.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term, Simplified Method	6	P6Y
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 1.77	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	15	437

Stock-Based Compensation Stoc74

Stock-Based Compensation Stock-Based Compensation (Options) (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	15	437
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 2.68
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	(7)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price	$ 5.62
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	483	475
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 4.02	$ 4.09
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	141
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 4.12

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Increase (decrease) in deferred tax asset valuation allowance										$ 24.4	$ 16.8
Operating Loss Carryforwards	$ 725.8									725.8
Annual limitation of NOL carryforwards and tax credits generated prior to ownership change										2.9
Impairment of excess reorganization value										0	137.2
Provision (benefit) for income taxes	0	$ 0	$ 0	$ 0.6	$ 0	$ 0	$ 0	$ 0.3		0.6	0.3
Other Comprehensive Income (Loss), Tax										0	0
Liability for Uncertain Tax Positions, Noncurrent	0.4				1					0.4	1	$ 1.3
Unrecognized Tax Benefits, Income Tax Penalties Expense Reduction										(0.4)	(0.2)
Income Tax Examination, Penalties and Interest Expense Reduction (Increase)										0.1	0.1
Income Tax Examination, Penalties and Interest Accrued	0.1				$ 0.2					0.1	$ 0.2
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	$ 17.7									$ 17.7
Scenario, Forecast [Member]
Unrecognized Tax Benefits, Income Tax Penalties Expense Reduction									$ (0.2)

Income Taxes Income Taxes (Taxe

Income Taxes Income Taxes (Taxes by Jurisdiction) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Current Income Tax Expense (Benefit)									$ (0.6)	$ (0.3)
Provision (benefit) for income taxes	$ 0	$ 0	$ 0	$ (0.6)	$ 0	$ 0	$ 0	$ (0.3)	(0.6)	(0.3)
State and Local Jurisdiction [Member]
Current Income Tax Expense (Benefit)									$ (0.6)	$ (0.3)

Income Taxes Income Taxes (Defe

Income Taxes Income Taxes (Deferred Income Taxes) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Components of Deferred Tax Assets and Liabilities [Abstract]
Deferred Tax Assets, Employee Benefits Costs	$ 139.3	$ 140.8
Deferred Tax Assets, Inventory	0	3.1
Deferred Tax Assets, Property, Plant and Equipment	318.8	437.1
Deferred Tax Assets, Net Operating Loss and Credit Carryforwards	254.9	114.3
Deferred Tax Assets, Accrued Expenses	14.9	9.1
Deferred Tax Assets, Other	12.6	11.9
Deferred Tax Assets, Gross	740.5	716.3
Deferred Tax Assets, Valuation Allowance	(702.2)	(676.4)
Deferred Tax Assets, Net of Valuation Allowance	38.3	39.9
Deferred Tax Liabilities, Inventory	2.6
Deferred Tax Liabilities, Intangible Assets	33	37.3
Deferred Tax Liabilities, Prepaid Expenses	2.7	2.6
Deferred Tax Liabilities	$ 38.3	$ 39.9

Income Taxes Income Taxes (Rate

Income Taxes Income Taxes (Rate Reconciliation) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Effective Income Tax Rate Reconciliation, Deduction, Percent [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%	35.00%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent	(6.00%)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Percent		(26.00%)
Effective Income Tax Rate Reconciliation, Deduction, Other, Percent	(3.00%)	(1.00%)
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent	(36.00%)	(9.00%)
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent	(1.00%)	1.00%
Effective Income Tax Rate Reconciliation, Percent	1.00%	0.00%

Income Taxes Income Taxes (Unre

Income Taxes Income Taxes (Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Liability for Uncertain Tax Positions, Noncurrent	$ 0.4	$ 1	$ 1.3
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	$ (0.6)	$ (0.3)

Net Income Per Share (Narrative

Net Income Per Share (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Interest expense	$ 4.9	$ 4.7	$ 5.1	$ 5	$ 5	$ 4.8	$ 4.9	$ 4.9	$ 19.7	$ 19.6

Net Income Per Share (Schedule

Net Income Per Share (Schedule of Income Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Income Per Share Calculation [Line Items]
Net loss	$ (8.2)	$ (41.3)	$ (2.9)	$ (14.6)	$ (101.8)	$ (55.1)	$ (15.1)	$ (15.4)	$ (67)	$ (187.4)
Interest expense on convertible notes	$ 4.9	$ 4.7	$ 5.1	$ 5	$ 5	$ 4.8	$ 4.9	$ 4.9	$ 19.7	$ 19.6
Weighted average common shares									9.1	9
Denominator for basic calculation									9.1	9
Weighted Average Number of Shares Outstanding, Basic and Diluted									9.1	9
Net loss per share - basic and diluted	$ (0.90)	$ (4.54)	$ (0.32)	$ (1.60)	$ (11.19)	$ (6.05)	$ (1.68)	$ (1.71)	$ (7.36)	$ (20.82)

Net Income Per Share Net Income

Net Income Per Share Net Income Per Share (Schedule of Securities Excluded from Net Income Per Share) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Options excluded from diluted net income per share	368,000	375,000
Minimum [Member]
Exercise price of excluded options	$ 3.90	$ 3.90
Maximum [Member]
Exercise price of excluded options	$ 5.62	$ 5.62

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2014
Class of Stock [Line Items]
Preferred Stock, Shares Authorized	20,000,000	20,000,000
Preferred Stock, Par Value Per Share	$ 1	$ 1
Common Stock, Shares, Issued	9,000,000
Common Stock, Shares Reserved for Future Issuance Under Management Incentive Plan	414,000		1,000,000
Operating Loss Carryforwards	$ 725.8
Common Class A [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized	70,000,000	70,000,000
Common Stock, Par or Stated Value Per Share	$ 0.10	$ 0.10
Common Stock, Shares, Issued	7,563,600	7,563,600
Common Class B [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized	30,000,000	30,000,000
Common Stock, Par or Stated Value Per Share	$ 0.10	$ 0.10
Common Stock, Shares, Issued	1,436,400	1,436,400

Commitment and Contingencies (D

Commitment and Contingencies (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Jun. 30, 2016	Sep. 30, 2015	Dec. 31, 2016
Decontamination and decommissioning obligations			$ 38.6
ARO financial assurance			29.4
Termination benefit costs	$ 0.1	$ 8.7	$ 0.4

Commitments and Contingencies85

Commitments and Contingencies Commitments and Contingencies (Minimum Operating Lease Payments) (Details) $ in Millions	Dec. 31, 2016USD ($)
Operating Leased Assets [Line Items]
Operating leases, future minimum payments due, 2016	$ 3.1
Operating leases, future minimum payments due, 2017	2.4
Operating leases, future minimum payments due, 2018	1.6
Operating leases, future minimum payments due, 2019	0.9
Operating leases, future minimum payments due, 2020	0.9
Operating leases, future minimum payments due, thereafter	5.7
Operating leases, future minimum payments due	$ 14.6

Segment Information Schedule of

Segment Information Schedule of Revenue by Geographic Ares (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue United States									$ 242.8	$ 272.8
Revenue Japan									49.1	77.8
Revenue Belgium										55.5
Revenue Other Countries									19.4	12.1
Revenue Foreign									68.5	145.4
Revenues	$ 136.5	$ 21.4	$ 63.4	$ 90	$ 157.9	$ 29.2	$ 63.3	$ 167.8	$ 311.3	$ 418.2

Segment Information (Segment Re

Segment Information (Segment Reporting Information) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Revenues [Abstract]
Total Revenue	$ 136.5	$ 21.4	$ 63.4	$ 90	$ 157.9	$ 29.2	$ 63.3	$ 167.8	$ 311.3	$ 418.2
Gross Profit	$ 25.9	$ (2.1)	$ 5.5	$ 15.8	$ 82.1	$ (24.4)	$ 4.3	$ 6.9	45.1	68.9
Low Enriched Uranium Segment [Member]
Revenues [Abstract]
Revenue, Goods									272.8	355.4
Gross Profit									38.5	70.1
Contract Services Segment [Member]
Revenues [Abstract]
Revenue, Contract Services									38.5	62.8
Gross Profit									6.6	(1.2)
Separative Work Units [Member] | Low Enriched Uranium Segment [Member]
Revenues [Abstract]
Revenue, Goods									258.5	289.9
Uranium [Member] | Low Enriched Uranium Segment [Member]
Revenues [Abstract]
Revenue, Goods									$ 14.3	$ 65.5

Segment Information Segment Inf

Segment Information Segment Information (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting [Abstract]
Revenue from top 10 customers	90.00%
Revenue from top 4 customers	50.00%
Revenue from first customer over 10 percent	15.00%	25.00%
Revenue from second customer over 10 percent	12.00%	13.00%
Revenue from third customer over 10 percent	12.00%	15.00%
Revenue from fourth customer over 10 percent	11.00%	10.00%
Assets LEU segment	$ 686	$ 795.3
Assets contract services segment	27.5	24.8
Assets	$ 713.5	$ 820.1

Subsequent Event (Details)

Subsequent Event (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Subsequent Event [Line Items]
Long-term debt		$ 234.1	$ 247	$ 239.7
Extinguishment of debt		$ 26.1
Debt Instrument, Interest Rate, Stated Percentage		8.00%
Preferred Stock, Par Value Per Share		$ 1	$ 1
Gain on early extinguishment of debt		$ 16.7	$ 0
Scenario, Forecast [Member]
Subsequent Event [Line Items]
Extinguishment of debt	$ 204.9
Preferred Stock, Shares Outstanding	104,574
Preferred Stock, Par Value Per Share	$ 1,000
Cash paid in exchange	$ 27.6
Preferred Stock	5
Gain on early extinguishment of debt	34
Scenario, Forecast [Member] | Payment in Kind (PIK) Note [Member]
Subsequent Event [Line Items]
Long-term debt	29.6
Scenario, Forecast [Member] | Senior Notes [Member]
Subsequent Event [Line Items]
Long-term debt	$ 136
Debt Instrument, Interest Rate, Stated Percentage	8.25%
Senior Notes	$ 74.3

Quarterly Results of Operatio90

Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Total Revenue	$ 136.5	$ 21.4	$ 63.4	$ 90	$ 157.9	$ 29.2	$ 63.3	$ 167.8	$ 311.3	$ 418.2
Cost of sales	110.6	23.5	57.9	74.2	75.8	53.6	59	160.9	266.2	349.3
Gross profit (loss)	25.9	(2.1)	5.5	15.8	82.1	(24.4)	4.3	6.9	45.1	68.9
Advanced technology costs	9.3	21.9	4.7	12	25.3	1.9	4	1.8	47.9	33
Selling, general and administrative	11.6	10.7	12.5	11.4	10.5	13.5	6.3	12.3	46.2	42.6
Amortization of intangible assets	4.9	1.7	2.7	3.2	6.3	1.1	2	4	12.5	13.4
Impairment of excess reorganization value									0	137.2
Special charges for workforce reductions	0.2	0.6	0.6	0	(0.1)	9.8	2.9	0.6	1.4	13.2
Gains on sales of assets	(0.2)	(0.3)	(0.4)	(0.3)	(0.3)	(0.3)	(0.7)	(0.8)	(1.2)	(2.1)
Operating (loss)	0.1	(36.7)	(14.6)	(10.5)	(96.8)	(50.4)	(10.2)	(11)	(61.7)	(168.4)
Gain on early extinguishment of debt and debt restructuring costs	3.7		(16.7)						(13)
Gain on early extinguishment of debt and debt restructuring costs									(16.7)	0
Interest expense	4.9	4.7	5.1	5	5	4.8	4.9	4.9	19.7	19.6
Investment income	(0.3)	(0.1)	(0.1)	(0.3)	0	(0.1)	0	(0.2)	(0.8)	(0.3)
Provision (benefit) for income taxes	0	0	0	(0.6)	0	0	0	(0.3)	(0.6)	(0.3)
Net income (loss)	$ (8.2)	$ (41.3)	$ (2.9)	$ (14.6)	$ (101.8)	$ (55.1)	$ (15.1)	$ (15.4)	$ (67)	$ (187.4)
Net loss per share - basic and diluted	$ (0.90)	$ (4.54)	$ (0.32)	$ (1.60)	$ (11.19)	$ (6.05)	$ (1.68)	$ (1.71)	$ (7.36)	$ (20.82)