Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2017	Mar. 01, 2018	Jun. 30, 2017
Document and Entity Information
Entity Registrant Name	CENTRUS ENERGY CORP
Entity Central Index Key	0001065059
Trading Symbol	LEU
Current Fiscal Year End Date	--12-31
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		9,038,751
Document Fiscal Year Focus	2017
Entity Well-known Seasoned Issuer	No
Entity Public Float			$ 22,200,000
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Document Fiscal Period Focus	Q4

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents	$ 208.8	$ 260.7
Accounts receivable, net	60.2	19.9
Inventories	153.1	177.4
Deferred costs associated with deferred revenue	122.3	89.3
Other current assets	22.5	13.3
Total current assets	566.9	560.6
Property, Plant and Equipment, Net	4.9	6.0
Deposits for surety bonds	19.7	29.5
Intangible assets	82.7	93.3
Other long-term assets	1.1	24.1
Total Assets	675.3	713.5
Current Liabilities
Accounts payable and accrued liabilities	53.3	46.4
Payables under SWU purchase agreements	79.4	59.6
Inventories owed to customers and suppliers	77.9	57.5
Deferred revenue	191.8	123.6
Decontamination and decommissioning obligations	1.0	38.6
Total current liabilities	403.4	325.7
Long-term debt	157.5	234.1
Postretirement health and life benefit obligations	154.2	171.3
Pension benefit liabilities	161.6	179.9
Other long-term liabilities	17.5	38.6
Total liabilities	894.2	949.6
Commitments and contingencies (Note 16)
Stockholders' Equity (Deficit)
Preferred stock	4.6
Excess of capital over par value	60.0	59.5
Accumulated deficit	(284.5)	(296.7)
Accumulated other comprehensive income, net of tax	0.1	0.2
Total stockholders’ deficit	(218.9)	(236.1)
Total liabilities and stockholders’ deficit	675.3	713.5
Common Class A [Member]
Stockholders' Equity (Deficit)
Common stock	0.8	0.8
Common Class B [Member]
Stockholders' Equity (Deficit)
Common stock	0.1	0.1
Preferred Series B [Member]
Stockholders' Equity (Deficit)
Preferred stock	$ 4.6	$ 0.0

CONSOLIDATED BALANCE SHEETS (Parentheticals) - USD ($)	12 Months Ended
CONSOLIDATED BALANCE SHEETS (Parentheticals) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Preferred Stock, Par Value Per Share	$ 1.00	$ 1.00
Preferred Stock, Shares Authorized	20,000,000	20,000,000
Preferred Stock, Dividend Rate, Percentage	7.50%
Preferred Stock, Shares Issued	104,574
Preferred Stock, Liquidation Preference, Value	$ 111,500,000
Common Stock, Shares, Issued	9,038,751
Common Class A [Member]
Common Stock, Par Value Per Share	$ 0.10	$ 0.10
Common Stock, Shares Authorized	70,000,000	70,000,000
Common Stock, Shares, Issued	7,632,669	7,563,600
Common Class B [Member]
Common Stock, Par Value Per Share	$ 0.10	$ 0.10
Common Stock, Shares Authorized	30,000,000	30,000,000
Common Stock, Shares, Issued	1,406,082	1,436,400

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Revenue:
Contract services	$ 23.0	$ 38.5
Total Revenue	218.4	311.3
Cost of Sales:
Separative work units and uranium	136.1	234.3
Contract services	25.5	31.9
Total cost of sales	161.6	266.2
Gross profit (loss)	56.8	45.1
Advanced technology costs	15.7	47.9
Selling, general and administrative	43.1	46.2
Amortization of intangible assets	10.6	12.5
Special charges for workforce reductions	9.5	1.4
Gains on sales of assets	(4.6)	(1.2)
Operating income (loss)	(17.5)	(61.7)
Gain on early extinguishment of debt and debt restructuring costs	(33.6)	(13.0)
Interest expense	5.3	19.7
Investment income	(1.3)	(0.8)
Loss before income taxes	12.1	(67.6)
Provision (benefit) for income taxes	(0.1)	(0.6)
Net income (loss)	12.2	(67.0)
Preferred stock dividends, undeclared and cumulative	6.9
Net income (loss) allocable to common stockholders	$ 5.3	$ (67.0)
Net income (loss) per share - basic and diluted	$ 0.58	$ (7.36)
Weighted-average number of shares outstanding:
Weighted Average Number of Shares Outstanding, Basic and Diluted	9.1	9.1
Separative Work Units [Member]
Revenue:
Revenue, Goods	$ 195.4	$ 258.5
Uranium [Member]
Revenue:
Revenue, Goods	$ 0.0	$ 14.3

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Net income (loss)	$ 12.2	$ (67.0)
Prior service credit arising during the period	0.0	(3.6)
Amortization of prior service costs (credits)	(0.1)	(0.3)
Other comprehensive income (loss), before tax	(0.1)	(3.9)
Income tax expense related to items of other comprehensive income	0.0	0.0
Other comprehensive income (loss), net of tax	(0.1)	(3.9)
Comprehensive income (loss)	$ 12.1	$ (70.9)

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash Flows from Operating Activities
Net income (loss)	$ 12.2	$ (67.0)
Adjustments to reconcile net income (loss) to net cash (used in) operating activities:
Depreciation and amortization	12.0	13.1
Immediate recognition of net actuarial losses	(25.8)	1.4
Interest on paid-in-kind toggle notes	2.9	9.7
Gain on early extinguishment of debt and debt restructuring costs	(33.6)	(16.7)
Gain on sale of assets	(4.6)	(1.2)
Non-cash reorganization items	0.0	3.0
Changes in operating assets and liabilities:
Accounts receivable – (increase) decrease	(17.6)	6.5
Inventories, net – (increase) decrease	44.7	89.5
Payables under SWU purchase agreements – increase (decrease)	19.8	(25.8)
Deferred revenue, net of deferred costs – increase (decrease)	15.9	13.4
Accounts payable and other liabilities – (decrease)	(43.8)	10.4
Other, net	(7.2)	1.4
Net Cash (Used in) Operating Activities	(25.1)	37.7
Cash Flows Provided by Investing Activities
Capital expenditures	(0.5)	(3.0)
Proceeds from sales of assets	4.7	1.5
Deposits for surety bonds - net (increase) decrease	0.0	0.3
Net Cash Provided by Investing Activities	4.2	(1.2)
Cash Flows Used in Financing Activities
Common stock issued (purchased), net	27.6	9.8
Payment of interest classified as debt	(3.4)
Net Cash (Used in) Financing Activities	(31.0)	(9.8)
Net (Decrease)	(51.9)	26.7
Cash and Cash Equivalents at Beginning of Period	260.7	234.0
Cash and Cash Equivalents at End of Period	208.8	260.7
Supplemental Cash Flow Information:
Interest paid	4.2	6.5
Exchange of debt for Series B preferred stock	4.6
Conversion of interest payable-in-kind to long-term debt	$ 0.4	$ 3.4

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	Preferred Stock [Member] Preferred Series B [Member]	Common Stock [Member] Common Class A [Member]	Common Stock [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, 2015	$ (165.7)		$ 0.8	$ 0.1	$ 59.0	$ (229.7)	$ 4.1
Net income (loss)	(67.0)
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
Net income (loss)	12.2
Stock issued during period		$ 4.6
Other comprehensive income, net of tax (Note 14)	(0.1)						(0.1)
Restricted and other common stock issued, net of amortization	0.5				0.5
Ending Balance at Dec. 31, 2017	$ (218.9)	$ 4.6	$ 0.8	$ 0.1	$ 60.0	$ (284.5)	$ 0.1

Special Charges

12 Months Ended

Dec. 31, 2017

Restructuring and Related Activities [Abstract]

Special Charges

SPECIAL CHARGES

Evolving Business Needs

Evolving business needs have resulted in workforce reductions since 2013. For the years ended December 31, 2017 and 2016, special charges included estimated employee termination benefits of $2.4 million and $0.3 million, respectively. Centrus expects to make payments primarily in the first quarter of 2018 related to the $0.8 million balance payable at December 31, 2017.

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 systems. The Company incurred advisory costs of $6.3 million in 2017 and $1.0 million in 2016 related to the reengineering project.

Piketon Demonstration Facility

In February 2016, 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 effective October 2015, Centrus incurred a special charge in 2015 for estimated employee termination benefits. Special charges for additional severance benefits totaled $1.1 million in 2017 and $0.1 million in 2016. Of the remaining $5.7 million balance at December 31, 2017, $3.1 million is classified as current and included in Accounts Payable and Accrued Liabilities in the consolidated balance sheet and the remaining $2.6 million is included in Other Long-Term Liabilities in the consolidated balance sheet and is expected to be paid in 2019.

A summary of termination benefit activity and related liabilities follows (in millions):



	Liability Dec. 31, 2015		2016					Liability Dec. 31, 2016		2017					Liability Dec. 31, 2017
	Liability Dec. 31, 2015		Charges for Termination Benefits		Paid			Liability Dec. 31, 2016		Charges for Termination Benefits		Paid/ Settled			Liability Dec. 31, 2017
Workforce reductions:
Evolving business needs	$	0.3	$	0.3	$	(0.5	)	$	0.1	$	2.4	$	(1.7	)	$	0.8
Piketon demonstration facility	8.4		0.1		(3.1		)	5.4		1.1		(0.8		)	5.7
	$	8.7	$	0.4	$	(3.6	)	$	5.5	$	3.5	$	(2.5	)	$	6.5

Summary of Significant Accounting Policies (Notes)	12 Months Ended
Summary of Significant Accounting Policies (Notes)	Dec. 31, 2017
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”). 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 Low-enriched uranium (“LEU”) consists of two components: separative work units (“SWU”) and uranium. SWU is a standard unit of measurement that represents the effort required to transform a given amount of natural uranium into two components: enriched uranium having a higher percentage of U²³⁵ and depleted uranium having a lower percentage of U²³⁵. The SWU contained in LEU is calculated using an industry standard formula based on the physics of enrichment. The amount of enrichment deemed to be contained in LEU under this formula is commonly referred to as its SWU component and the quantity of natural uranium deemed to be used in the production of LEU under this formula is referred to as its uranium 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 all, or some portion, 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 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. Refer also to Carrying Value of Long-Lived Assets below. 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’ 8.0% paid-in-kind (“PIK”) toggle notes (the “8.0% PIK Toggle Notes”) and its 8.25% notes (the “8.25% Notes”) are recorded at face value and the fair value is disclosed. The estimated fair value of each of the 8.0% PIK Toggle Notes and the 8.25% Notes is based on the trading price nearest the balance sheet date observed on secondary markets. 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. Utility customers in general have the option to defer physical receipt of LEU or uranium purchased from us beyond the contractual sale period. In such cases, title to LEU or uranium is transferred to the customer and an obligation for Centrus is created and a receivable is recorded. Cash is collected for the receivable under normal credit terms. The obligation is included in Deferred Revenue and Advances from Customers on the consolidated balance sheet and the customer-titled product is classified as Deferred Costs Associated with Deferred Revenue. Risk of loss remains with Centrus until physical delivery occurs. The recognition of revenue and related cost of sales occurs at the time physical delivery occurs and risk of loss transfers to the customer, which may occur beyond one year. The timing of physical delivery, subject to notice period requirements, is at the option of the customer. As such, deferred costs and deferred revenue are classified within current assets and current liabilities, respectively. 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 contracts with UT-Battelle provide for fixed payments for monthly reports or for fixed payments upon completion of milestones. For contracts that provide fixed payments for monthly reports, revenue is recognized as deliverables are completed and as fees are earned. For contracts that provide fixed payments for completion of milestones, revenue is recognized as each milestone is completed. Centrus and DOE have yet to fully settle the Company’s claims for reimbursements for certain pension and postretirement benefits costs related to past contract work performed at the Portsmouth and Paducah sites. There is the potential for additional revenue to be recognized for this work pending the outcome of legal proceedings related to the Company’s claims for payment and the potential release of previously established valuation allowances on receivables. As a result of the application of fresh start accounting following the Company’s emergence from Chapter 11 bankruptcy on September 30, 2014, the receivables related to the Company’s claims for payment are carried at fair value as of September 30, 2014, which is net of the valuation allowances. Refer to Note 4, Receivables, for details. 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 NRC requirements. 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 has determined that this standard will not have a material impact on its financial position or results of operations. The Company adopted FASB ASU No. 2014-09 on January 1, 2018 using the modified retrospective method. 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 became 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 adoption of ASU 2016-09 did not 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, and is to be applied retrospectively. Under the retrospective transition, transaction costs of $9.0 million incurred in the three months ended March 31, 2017, related to the February 14, 2017, securities exchange described in Note 9, Debt, will be reclassified from cash used in operating activities to cash used in financing activities. 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. 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. The provisions of ASU 2016-18 are not expected to have a material impact on the Company’s consolidated financial statements. In March 2017, the FASB issued ASU 2017-07, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. ASU 2017-07 requires the service cost component of net periodic benefit costs be presented with other employee compensation costs and other components of net periodic benefit costs to be presented outside of any subtotal of operating income. In addition, only the service cost component of net periodic benefit costs is eligible for capitalization in assets when applicable. ASU 2017-07 will become effective for the Company beginning in the first quarter of 2018. The provisions of ASU 2017-17 related to the presentation of the components of net periodic benefit costs are to be applied retrospectively. Annual net periodic benefit costs (credits) of ($26.5 million) and ($0.7 million) for 2017 will be reclassified from cost of sales and selling, general and administrative (SG&A) expense, respectively, to other nonoperating income in the consolidated statement of operations. The provision of ASU 2017-17 allowing only the service cost component of net periodic benefit costs to be capitalized will be adopted on a prospective basis and is not expected to have a significant impact on the Company’s consolidated financial statements as no portion of net periodic benefit costs were capitalized in assets during 2017. In February 2018, the FASB issued ASU 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. ASU 2018-02 allows a reclassification from accumulated other comprehensive income to retained earnings for the tax effects of items within accumulated other comprehensive income (stranded tax effects) resulting from the decrease in the corporate income tax rate reflected in the December 2017 Tax Cuts and Jobs Act. The provisions of ASU 2018-02 are effective for all fiscal years beginning after December 15, 2018 and interim periods within those years. Early adoption is permitted. The Company is evaluating the effects that ASU 2018-02 will have its consolidated financial statements.

Contract Services and Advanced Technology License and Decommissioning Costs	12 Months Ended
	Dec. 31, 2017
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. The recently completed fixed price contract between Centrus and UT-Battelle (the “2017 ORNL Contract”) was for the period from October 1, 2016, through September 30, 2017, and generated revenue of approximately $25.0 million. On October 26, 2017, the parties executed a new fixed priced contract for the period from October 1, 2017, through September 30, 2018, that is expected to generate revenue of approximately $16.0 million upon completion of defined milestones. The ORNL contracts have been funded incrementally. Funding for the program is provided to UT-Battelle by the federal government which is currently operating under a continuing resolution. The 2017 ORNL Contract provided for payments for monthly reports of deliverables of approximately $2.0 million per month and additional aggregate payments of $1.0 million based on completion of certain defined milestones. 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 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 work performed in the three months ended December 31, 2015, before entering into the 2016 ORNL Contract, were expensed 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 licenses from the U.S. Nuclear Regulatory Commission (“NRC”) at that location. Charges to Advanced Technology License and Decommissioning Costs in 2016 included demobilization costs of approximately $7.0 million incurred in early 2016 in preparation for the D&D of the Piketon facility. Charges in 2016 also included $19.0 million to increase the accrued D&D liability based on updated cost estimates that reflected changes in the approach and schedule. D&D costs commenced in the second quarter of 2016 and are charged against the D&D liability. Most of the D&D work was completed by December 31, 2017, and a credit of $5.9 million to Advanced Technology License and Decommissioning Costs was recognized in the fourth quarter of 2017 as a result of using primarily internal resources and less contractor support as well as efficiencies achieved. Refer to Note 16, Commitments and Contingencies, for additional details.

Accounts Receivable

12 Months Ended

Dec. 31, 2017

Accounts Receivable, Net, Current [Abstract]

Accounts Receivable

RECEIVABLES

A summary of accounts receivable, net, follows:



	December 31,
($ millions)	2017		2016

Utility customers and other	$	42.3	$	15.3
Contract services, primarily DOE	17.9		4.6
Accounts receivable, net	$	60.2	$	19.9

Centrus formerly performed site services work under contracts with DOE and its contractors at the former Portsmouth and Paducah gaseous diffusion plants. There is the potential for additional revenue to be recognized for this work pending the outcome of legal proceedings related to the Company’s claims for payment and the potential release of previously established valuation allowances on receivables.

First Quarter 2018 Settlement

On January 11, 2018, the Company entered into a settlement agreement with DOE and the United States government regarding breach of contract claims relating to work performed by the Company under contracts with DOE and subcontracts with DOE contractors. As of December 31, 2017, the receivables balance related to the claims being settled is $14.5 million.

Under the terms of the settlement agreement, DOE has agreed to settle all claims raised as part of and subsequent to the litigation for a total of $24.0 million and provide a complete close out of all such contracts and subcontracts settled under the settlement agreement without any further audit or review of the Company’s costs or incurred cost submissions. The $24.0 million settlement amount will be satisfied by applying approximately $19.3 million of unapplied payments received from the United States government in prior years and the United States government making a cash payment to the Company of approximately $4.7 million.

As of December 31, 2017, the receivables balance of $14.5 million related to the settlement is classified as Accounts Receivable, net on the consolidated balance sheet based on the impending settlement. Receivables from DOE related to the claims were included in Other Long-Term Assets on the consolidated balance sheet in prior periods.

As of December 31, 2017, unapplied payments from DOE of $19.3 million are classified as Deferred Revenue and Advances from Customers on the consolidated balance sheet based on the impending settlement. These amounts were included in Other Long-Term Liabilities on the consolidated balance sheet in prior periods.

Claims Related to Pension and Postretirement Benefits Costs

Unresolved claims with DOE relate to certain pension and postretirement benefits costs. 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 Contract Disputes Act 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.

- Definition

The entire disclosure for claims held for amounts due a entity, excluding financing receivables. Examples include, but are not limited to, trade accounts receivables, notes receivables, loans receivables. Includes disclosure for allowance for credit losses.

+ References + Details

Property, Plant and Equipment

12 Months Ended

Dec. 31, 2017

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, 2016			Additions / (Depreciation)			Retirements			December 31, 2017
Land	$	1.2		$	—		$	—		$	1.2
Leasehold improvements	3.0			0.2			—			3.2
Machinery and equipment	1.7			0.1			(0.5		)	1.3
Other	0.9			0.2			—			1.1
Property, plant and equipment, gross	6.8			0.5			(0.5		)	6.8
Accumulated depreciation	(0.8		)	(1.4		)	0.3			(1.9		)
Property, plant and equipment, net	$	6.0		$	(0.9	)	$	(0.2	)	$	4.9

Depreciations expense was $1.4 million and $0.6 million for the years ended December 31, 2017 and 2016, respectively.

The Company sold assets and property in 2017 and 2016 related to its operations and the American Centrifuge project that were no longer needed (in millions):



	Year Ended December 31,
	2017			2016
Sales of assets and property, net of auction fees and other costs	$	4.8		$	1.2
Less: net carrying value	(0.2		)	—
Gain on sales of assets	$	4.6		$	1.2

Cash proceeds received	$	4.7		$	1.5

Cash proceeds for the years ended December 31, 2017 and 2016 include $0.2 million and $0.1 million, respectively, which were included in Accounts Receivable as of December 31 of the prior year.

Intangible Assets

12 Months Ended

Dec. 31, 2017

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 the date the Company emerged from bankruptcy, September 30, 2014, and reflect the conditions at that time. The intangible asset related to the sales order book is amortized as the order book existing at emergence is reduced, principally as a result of deliveries to customers. The intangible asset related to customer relationships 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.



( in millions)	December 31, 2017						December 31, 2016
	Gross Carrying Amount		Accumulated Amortization		Net Amount		Gross Carrying Amount		Accumulated Amortization		Net Amount
Sales order book	$	54.6	$	25.9	$	28.7	$	54.6	$	19.9	$	34.7
Customer relationships	68.9		14.9		54.0		68.9		10.3		58.6
Total	$	123.5	$	40.8	$	82.7	$	123.5	$	30.2	$	93.3

The amount of amortization expense for intangible assets in each of the succeeding years is estimated to be as follows (in millions):



2018	$	8.1
2019	7.1
2020	10.3
2021	8.9
2022	9.0
Thereafter	39.3
Total	$	82.7

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Debt

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Debt

DEBT

A summary of long-term debt follows (in millions):



	Maturity	December 31, 2017		December 31, 2016
8.25% Notes:	Feb. 2027
Principal		$	74.3	$	—
Interest		58.1		—
8.25% Notes		132.4		—
8% PIK Toggle Notes	Sep. 2019^(a)	31.3		234.6
Subtotal		163.7		234.6
Less deferred issuance costs		0.1		0.5
Total debt		163.6		234.1
Less current portion		6.1		—
Long-term debt		$	157.5	$	234.1

(a) Maturity can be extended to September 2024 upon the satisfaction of certain funding conditions described below.

On February 14, 2017, pursuant to an exchange offer and consent solicitation, Centrus exchanged $204.9 million of 8% 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. The exchange is accounted for as a troubled debt restructuring (“TDR”) under Accounting Standards Codification Subtopic 470-60, Debt-Troubled Debt Restructurings by Debtors. 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. Accordingly, the Company recognizes the 8.25% Notes on the consolidated balance sheet as the sum of the principal balance and all future interest payments. The Company recognized a gain of $33.6 million related to the note exchange in 2017, which is net of transaction costs of $9.0 million and previously deferred issuance costs related to the 8% PIK Toggle Notes of $0.4 million. The effect on both basic and diluted earnings per share for 2017 was $3.70 per share, which assumes the gain would not affect the Company’s income tax benefit for 2017. Refer to Note 15, Stockholders’ Equity for details related to the newly issued preferred stock.

8.25% Notes

Interest on the 8.25% Notes is payable semi-annually in arrears as of February 28 and August 31 based on a 360-day year consisting of twelve 30-day months. The 8.25% Notes mature on February 28, 2027. As described above, all future interest payment obligations on the 8.25% Notes are included in the carrying value of the 8.25% Notes. As a result, the Company’s reported interest expense will be less than its contractual interest payments throughout the term of the 8.25% Notes. As of December 31, 2017, $6.1 million of interest is recorded as current and classified as Accounts Payable and Accrued Liabilities in the consolidated balance sheet.

The 8.25% Notes rank equally in right of payment with all of our existing and future unsubordinated indebtedness other than our Issuer Senior Debt and our Limited Secured Acquisition Debt (each as defined below). The 8.25% Notes rank senior in right of payment to all of our existing and future subordinated indebtedness and to certain limited secured acquisition indebtedness of the Company (the “Limited Secured Acquisition Debt”). The Limited Secured Acquisition Debt includes (i) any indebtedness, the proceeds of which are used to finance all or a portion of an acquisition or similar transaction if any lender’s lien is solely limited to the assets acquired in such a transaction and (ii) any indebtedness, the proceeds of which are used to finance all or a portion of the American Centrifuge project or another next generation enrichment technology if any lender’s lien is solely limited to such assets, provided that a lien securing the 8.25% Notes that is junior with respect to the lien securing such indebtedness will be limited to the assets acquired with such Limited Secured Acquisition Debt.

The 8.25% Notes are subordinated in right of payment to certain indebtedness and obligations of the Company, as described in the 8.25% Notes Indenture (the “Issuer Senior Debt”), including (i) any indebtedness of the Company (inclusive of any indebtedness of Enrichment Corp.) under a future credit facility up to $50 million with a maximum net borrowing of $40 million after taking into account any minimum cash balance (unless a higher amount is approved with the consent of the holders of a majority of the aggregate principal amount of the 8.25% Notes then outstanding), (ii) any revolving credit facility to finance inventory purchases and related working capital needs, and (iii) any indebtedness of the Company to Enrichment Corp. under the secured intercompany notes.

The 8.25% Notes are guaranteed on a subordinated and limited basis by, and secured by substantially all of the assets of, Enrichment Corp. The Enrichment Corp. guarantee is a secured obligation and ranks equally in right of payment with all existing and future unsubordinated indebtedness of Enrichment Corp. (other than Designated Senior Claims (as defined below) and Limited Secured Acquisition Debt) and senior in right of payment to all existing and future subordinated indebtedness of Enrichment Corp. and Limited Secured Acquisition Debt. The Enrichment Corp. guarantee is subordinated in right of payment to certain obligations of, and claims against, Enrichment Corp. described in the 8.25% Notes Indenture (collectively, the “Designated Senior Claims”), including obligations and claims:


•	under a future credit facility up to $50 million with a maximum net borrowing of $40 million after taking into account any minimum cash balance;


•	under any revolving credit facility to finance inventory purchases and related working capital needs;


•	held by or for the benefit of the Pension Benefit Guaranty Corporation (“PBGC”) pursuant to any settlement (including any required funding of pension plans); and


•	under surety bonds or similar obligations held by or on behalf of the U.S. government pursuant to regulatory requirements.

The liens securing the Enrichment Corp. guarantee of the PIK Toggle Notes and the 8.25% Notes are pari passu with each other, and are junior in priority with respect to the lien securing Limited Secured Acquisition Debt, which is limited to the assets acquired with such Limited Secured Acquisition Debt.

8% PIK Toggle Notes

Interest on the 8% PIK Toggle Notes is payable semi-annually in arrears on March 31 and September 30 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 8% PIK Toggle Notes in the form of PIK payments. For the semi-annual payments in 2016 and 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, 2017, is $0.6 million, of which the cash portion of $0.2 million is included in Accounts Payable and Accrued Liabilities and the PIK portion of $0.4 million is included in Other Long-term Liabilities. 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.

Financing costs for the 8% 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 8% PIK Toggle Notes.

The 8% PIK Toggle Notes 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 8% 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) and are senior in right of payment to all existing and future subordinated indebtedness of the Company. The 8% PIK Toggle Notes are subordinated in right of payment to the Issuer Senior Debt.

The 8% 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 8% 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 and Limited Secured Acquisition Debt) and senior in right of payment to all existing and future subordinated indebtedness of Enrichment Corp. and Limited Secured Acquisition Debt. The Enrichment Corp. guarantee is subordinated in right of payment to the Designated Senior Claims.

Fair Value Measurements

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Fair Value Measurements

FAIR VALUE MEASUREMENTS

Fair value is 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 of assets and liabilities, the following hierarchy is used in selecting inputs, with the highest priority given to Level 1, as these are the most transparent or reliable:


•	Level 1 – quoted prices for identical instruments in active markets.


•	Level 2 – quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs are observable in active markets.


•	Level 3 – valuations derived using one or more significant inputs that are not observable.

Financial Instruments Recorded at Fair Value (in millions)



	December 31, 2017								December 31, 2016
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Assets:
Cash and cash equivalents	$	208.8	$	—	$	—	$	208.8	$	260.7	$	—	$	—	$	260.7
Deferred compensation asset (a)	1.4		—		—		1.4		1.1				—		1.1

Liabilities:
Deferred compensation obligation (a)	1.4		—		—		1.4		1.1				—		1.1


(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. Trust funds are invested in mutual funds for which unit prices are quoted in active markets and are classified within Level 1 of the valuation hierarchy.

There were no transfers between Levels 1, 2 or 3 during the periods presented.

Other Financial Instruments

As of December 31, 2017, and December 31, 2016, 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 carrying value and estimated fair value of long-term debt follow (in millions):



	December 31, 2017					December 31, 2016
	Carrying Value			Estimated Fair Value ^(a)		Carrying Value		Estimated Fair Value ^(a)
8.25% Notes	$	132.4	^(b)	$	61.7	$	—	$	—
8% PIK Toggle Notes	31.3			25.1		234.6		107.4

^(a) Based on the trading price nearest the balance sheet date observed on secondary markets, which is considered a Level 2 input as of December 31, 2017, and a Level 1 input as of December 31, 2016, based on the frequency of trading.


^(b)	The carrying value of the 8.25% Notes as of December 31, 2017, consists of the principal balance of $74.3 million and the sum of interest payment obligations until maturity. Refer to Note 9, Debt.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Pension and Postretirement Health and Life Benefits

12 Months Ended

Dec. 31, 2017

Retirement Benefits, Description [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 3,100 employees and retirees 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:



	Defined Benefit Pension Plans						Postretirement Health and Life Benefit Plans
($ millions)	Year Ended December 31,						Year Ended December 31,
	2017			2016			2017			2016
Changes in Benefit Obligations:
Obligations at beginning of period	$	814.6		$	832.8		$	192.8		$	203.5
Actuarial (gains) losses, net	32.8			19.1			(24.8		)	(9.2		)
Service costs	3.7			3.8			—			—
Interest costs	32.2			35.4			7.2			8.2
Benefits paid	(59.3		)	(60.9		)	(14.5		)	(13.3		)
Lump sum benefits paid	(2.9		)	(12.2		)	—			—
Plan change	—			—			10.0			3.6
Administrative expenses paid	(3.2		)	(3.4		)	—			—
Obligations at end of period	817.9			814.6			170.7			192.8
Changes in Plan Assets:
Fair value of plan assets at beginning of period	634.1			656.3			7.7			13.8
Actual return on plan assets	84.4			50.2			0.1			0.5
Company contributions	1.5			4.1			8.5			6.7
Benefits paid	(59.3		)	(60.9		)	(14.5		)	(13.3		)
Lump sum benefits paid	(2.9		)	(12.2		)	—			—
Administrative expenses paid	(3.2		)	(3.4		)	—			—
Fair value of plan assets at end of period	654.6			634.1			1.8			7.7
Unfunded status at end of period	$	(163.3	)	$	(180.5	)	$	(168.9	)	$	(185.1	)

Amounts recognized in assets and liabilities:
Current liabilities	$	(1.7	)	$	(0.6	)	(14.7		)	(13.8		)
Noncurrent liabilities	(161.6		)	(179.9		)	(154.2		)	(171.3		)
	$	(163.3	)	$	(180.5	)	$	(168.9	)	$	(185.1	)
Amounts in accumulated other comprehensive income (loss), pre-tax:
Prior service cost (credit)	$	—		$	—		$	(2.5	)	$	(2.6	)

Discount rate used to determine benefit obligations at end of period:	3.7		%	4.1		%	3.6		%	3.9		%

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. There were no interim remeasurements in 2017.

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 $817.9 million as of December 31, 2017, and $814.6 million as of December 31, 2016. As of December 31, 2017, 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 Income (Loss)

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.



	Defined Benefit Pension Plans						Postretirement Health and Life Benefit Plans
($ millions)	Year Ended December 31,						Year Ended December 31,
	2017			2016			2017			2016
Net Periodic Benefit (Credits) Costs
Service costs	$	3.7		$	3.8		$	—		$	—
Interest costs	32.2			35.4			7.2			8.2
Expected return on plan assets (gains)	(40.7		)	(42.0		)	—			(0.3		)
Amortization of prior service costs (credits), net	—			—			(0.1		)	(0.3		)
Actuarial (gains) losses, net	(10.9		)	10.9			(24.9		)	(9.5		)
Loss on plan changes resulting from a pending legal settlement	—			—			10.0			—
Net periodic benefit (credits) costs	$	(15.7	)	$	8.1		$	(7.8	)	$	(1.9	)



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	—			—		0.1			0.3
Total loss recognized in other comprehensive income (loss), pre-tax	$	—		$	—	$	0.1		$	3.9
Total recognized in net periodic benefit costs (income) and other comprehensive income (loss), pre-tax	$	(15.7	)	$	8.1	$	(7.7	)	$	2.0

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.

Effective January 1, 2014, or for certain plan participants formerly represented by a collective bargaining unit, January 1, 2015, plan participants age 65 or older (“post-65”) have access to a range of medical plan choices with varying costs and benefits through a Medicare Exchange implemented by the Company. The Company provides an annual stipend for each of the post-65 retirees and post-65 spouses who enroll in the coverage through the exchange. Depending on the level of benefits elected by the participant, the participant may be required to make contributions in excess of the stipend amount.

The transition to the post-65 Medicare Exchange was reflected as a plan amendment that reduced plan obligations by $6.8 million as of December 31, 2014. This reduction in obligation was recognized in other comprehensive income in 2014 as a prior service credit. The prior service credit is being amortized into net periodic benefit cost as a credit over time. The post-65 Medicare Exchange stipend amount was increased for 2017. This increase in obligation of $3.6 million as of December 31, 2016, was recognized in other comprehensive income in 2016 as a prior service cost and is being amortized into net periodic benefit cost over time. The post-65 Medicare Exchange stipend amount was increased in 2018, as specified in a settlement agreement with the former collective bargaining unit. The settlement agreement also specifies the addition of catastrophic drug coverage. The settlement agreement is pending court approval, and the addition of catastrophic drug coverage is anticipated later in 2018. The benefit enhancement for 2018 has been, or is anticipated to be, applied to all post-65 participants regardless of past representation by the collective bargaining agreement. The increase in obligation of $10.0 million as of December 31, 2017, is recognized in net periodic benefit costs in 2017 as a plan change resulting from a pending legal settlement and is allocated to cost of sales for the LEU segment.

Assumptions Used to Determine Net Periodic Benefit Costs



	Defined Benefit Pension Plans		Postretirement Health and Life Benefit Plans
	Year Ended December 31,		Year Ended December 31,
	2017	2016	2017	2016
Discount rate	3.7%	4.1%	3.6%	3.9%
Expected return on plan assets	6.8%	6.8%	—	5.0%

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.

Healthcare cost trend rates used to measure postretirement health benefit obligations follow:



	December 31,
	2017	2016
Healthcare cost trend rate for the following year	6.5%	7.0%
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 as follows:



(in millions)	One-Percentage Point
	Increase		Decrease
Postretirement health benefit obligation	$	3.7	$	(3.4	)
Net periodic benefit costs (service and interest cost components only)	$	0.2	$	(0.1	)

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 for the defined benefit pension plans follows:



	December 31,
	2017		2016		2018 Target
Equity securities	49	%	41	%	40	-	60%
Debt securities	51		59		40	-	60
	100	%	100	%

Prefunding for the postretirement health and life benefit plans was discontinued in 2012 and the remaining assets are invested in short-term bond funds as of December 31, 2017, and are anticipated to be expended in early 2018. Benefit costs of the postretirement health and life benefit plans are primarily funded as costs are incurred.

Plan assets are measured at fair value. Following are the plan investments as of December 31, 2017 and 2016, categorized by the fair value hierarchy levels described in Note 10, Fair Value Measurements:



	Defined Benefit Pension Plans
(in millions)	Level 1				Level 2				Level 3				Total
	2017		2016		2017		2016		2017		2016		2017			2016
U.S. government securities	$	—	$	—	$	34.6	$	84.7	$	—	$	—	$	34.6		$	84.7
Corporate debt	—		—		119.7		217.0		—		—		119.7			217.0
Municipal bonds and non-U.S. government securities	—		—		3.5		6.2		—		—		3.5			6.2
Mortgage and asset backed securities	—		—		0.3		5.4		—		—		0.3			5.4
Fair value of investments by hierarchy level	$	—	$	—	$	158.1	$	313.3	$	—	$	—	$	158.1		$	313.3
Investments measured at NAV (a)													494.7			318.3
Accrued interest receivable													1.9			3.5
Unsettled transactions													(0.1		)	(1.0		)
Plan assets													$	654.6		$	634.1



	Postretirement Health and Life Benefit Plans
(in millions)	Level 1				Level 2				Level 3				Total
	2017		2016		2017		2016		2017		2016		2017		2016
Money market funds	$	—	$	0.2	$	—	$	—	$	—	$	—	$	—	$	0.2
Bond mutual funds	1.8		7.5		—		—		—		—		1.8		7.5
Equity mutual funds	—		—		—		—		—		—		—		—
Fair value of investments by hierarchy level	$	1.8	$	7.7	$	—	$	—	$	—	$	—	$	1.8	$	7.7

(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 $12.8 million to the qualified defined benefit pension plans, $1.8 million to the non-qualified defined benefit pension plans and $14.6 million to the postretirement health and life benefit plans in 2018. 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
2018	$	59.9	$	16.4
2019	58.2		15.2
2020	56.1		14.2
2021	54.9		13.4
2022	53.7		12.8
2023 to 2027	251.8		53.1

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 $2.3 million in 2017 and $2.4 million in 2016.

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 2017 and 2016.

Stock-Based Compensation

12 Months Ended

Dec. 31, 2017

Share-based Compensation [Abstract]

Stock-Based Compensation

STOCK-BASED COMPENSATION

The Company’s 2014 Equity Incentive Plan authorizes the issuance of 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 1,200,000 shares of Class A Common Stock. As of December 31, 2017, there were approximately 640,000 shares available for future awards, including approximately 120,000 shares associated with awards which were cancelled or forfeited without being exercised.

A summary of stock-based compensation costs follows (in millions):



	Year Ended December 31,
	2017		2016

Total stock-based compensation costs:
Restricted stock units	$	0.1	$	0.2
Stock options	0.4		0.3
Expense included in selling, general and administrative expense	$	0.5	$	0.5

Total recognized tax benefit	$	—	$	—

The total recognized tax benefit is reported at the federal statutory rate net of the tax valuation allowance.

Stock-based compensation cost is measured at the grant date, based on the fair value of the award, and is recognized on a straight-line basis over the requisite service period. As of December 31, 2017, there was $0.4 million of unrecognized compensation cost, adjusted for actual forfeitures, related to non-vested stock-based payments granted, of which $0.3 million relates to stock options and $0.1 million relates to restricted stock units. That cost is expected to be recognized over a weighted-average period of 0.9 years.

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 generally 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, 2017, approximately 95,000 shares of restricted stock units could potentially be converted to 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. For reporting periods prior to January 1, 2017, the Company used historical data to estimate pre-vesting option forfeitures at the time of grant and revised those estimates in subsequent periods if actual forfeitures differed from the estimates. Effective January 1, 2017, the Company recognizes forfeitures as they occur. 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. There were no option grants in the year ended December 31, 2017.



	Year Ended December 31, 2016

Options granted (in thousands)	15
Risk-free interest rate	1.91%
Expected volatility	75%
Expected option life (years)	6
Weighted-average grant date fair value	$1.77

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, 2016	483	$4.02	8.4	$1.1
Granted	—	—
Exercised	—	—
Forfeited/Cancelled	(58)	$3.12
Outstanding at December 31, 2017	425	$4.14	7.3	$0.1
Exercisable at December 31, 2017	236	$4.17	7.3	$0.1

Stock options outstanding and options exercisable at December 31, 2017, follow:



Stock Exercise Price	Options Outstanding (thousands)	Weighted Average Remaining Contractual Life in Years	Options Exercisable (thousands)

$5.62	22	6.9	22
$4.37	300	7.2	150
$3.90	23	7.6	15
$3.93	15	7.6	10
$2.71	50	7.8	34
$2.68	15	8.5	5

Income Taxes

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Income Taxes

INCOME TAXES

Benefit

The benefit from income taxes from continuing operations is as follows (in millions):



	Year Ended December 31,
	2017			2016
Current:
Federal	$	—		$	—
State and local	(0.1		)	(0.6		)
Foreign	—			—
	(0.1		)	(0.6		)
Deferred:
Federal	—			—
State and local	—			—
Foreign	—			—
	—			—
	$	(0.1	)	$	(0.6	)

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,
	2017			2016
Deferred tax assets:
Employee benefits costs	$	79.9		$	142.3
Inventory	2.4			—
Property, plant and equipment	187.0			318.8
Net operating loss and credit carryforwards	166.9			254.9
Accrued expenses	0.9			7.9
Long-term debt and financing costs	17.3			8.0
Other	5.5			8.6
	459.9			740.5
Valuation allowance	(440.7		)	(702.2		)
Deferred tax assets, net of valuation allowance	$	19.2		$	38.3

Deferred tax liabilities:
Inventory	$	—		$	2.6
Intangible assets	17.7			33.0
Prepaid expenses	1.5			2.7
Deferred tax liabilities	$	19.2		$	38.3
	$	—		$	—

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 operating losses since 2011 and substantial uncertainty to generate future taxable income that would lead to realization of the net deferred tax assets. When a change in the tax rate or tax law has an impact on deferred taxes, we apply the change based on the years in which the deferred taxes are expected to reverse. We record the impact of the change in our consolidated financial statements in the period of enactment. The decrease in net deferred tax assets before valuation allowance results primarily from the provisional remeasurement at 21% in accordance with the Tax Cut and Jobs Act of 2017 (the “Tax Act”). 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 $789.7 million that currently expire through 2037. 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 in 2014 of approximately $340 million as prescribed by Internal Revenue Code Section 108. Centrus also has state net operating losses of $18.1 million that currently expire through 2037. The deferred tax assets for state net operating losses and state unrealized built-in loss deductions have been reduced as a result of Centrus’ tax 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 can 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 post-ownership change period through certain depreciation and loss deductions, the same annual limitation for loss and tax credit carryforwards also applies generally to a built-in loss when it is recognized, unless the exception applies. Centrus can 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 state limitation will apply so that the combination of loss carryforwards and recognized built-in losses cannot exceed $2.9 million annually.

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,
	2017		2016
Federal statutory tax rate	35	%	35	%
Gain on early extinguishment of debt	(268	)	6
Tax Cuts and Jobs Act of 2017	2,382		—
Interest expense	4		(3	)
Other non-deductible expenses	1		—
Valuation allowance against net deferred tax assets	(2,156	)	(36	)
State income tax expense, net of federal benefit	1		(1	)
Effective tax rate	(1	)%	1	%

The Tax Act enacted on December 22, 2017 reduced the U.S. federal corporate income tax rate from 35% to 21%, effective January 1, 2018. The SEC staff issued Staff Accounting Bulletin 118 (“SAB 118”), which provides guidance on accounting for the tax effects of the Tax Act. SAB 118 provides a measurement period that should not extend beyond one year from the Tax Act enactment date for companies to complete the accounting under Accounting Standards Codification 740, Income Taxes (“ASC 740”). In accordance with SAB 118, a company must reflect the income tax effects of those aspects of the Tax Act for which the accounting under ASC 740 is complete. To the extent that a company’s accounting for certain income tax effects of the Tax Act is incomplete, but it can determine a reasonable estimate, it must record a provisional estimate in the financial statements.

As a result of the reduction of the federal corporate income tax rate, the net deferred tax assets have been remeasured as of December 31, 2017. Primarily as a result of the provisional remeasurement, the effective tax rate for the year ended December 31, 2017 includes a decrease to the net deferred tax assets of $288.9 million, or an increase to the effective tax rate of 2,382%. The effective tax rate also includes a decrease to the valuation allowance against net deferred tax assets of $261.5 million, or a decrease to the effective tax rate of (2,156)% and an adjustment to the gain on early extinguishment of debt of $32.5 million or a decrease to the effective tax rate of (268)%. The Tax Act did not affect the income tax provision for the year ended December 31, 2017. The adjustments to net deferred tax assets are provisional amounts based on information available as of December 31, 2017. We will recognize any changes to the provisional amounts as we refine our estimates of net deferred assets and the application of the Tax Act. We expect to complete our analysis of the provisional items during the second half of 2018.

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 a decrease to the effective tax rate of 36% and an adjustment to the gain on early extinguishment of debt of $4.1 million or an increase to the effective tax rate of 6%.

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 $0.3 million as of December 31, 2017, and $0.4 million as of December 31, 2016. If recognized, these tax benefits would impact the effective tax rate. As a result of changes to unrecognized tax benefits, the income tax provision (state tax, net of federal benefit) decreased $0.1 million during the year ended December 31, 2017, and $0.4 million during the year ended December 31, 2016. The liability for unrecognized tax benefits in the table below relates to unrecognized state income tax benefits. Centrus believes that the liability for unrecognized tax benefits will not change significantly in the next 12 months.

A reconciliation of the beginning and ending amount of unrecognized tax benefits follows (in millions):



	Year Ended December 31,
	2017			2016
Balance at beginning of the period	$	0.4		$	1.0
Additions to tax positions of current period	0.1			—
Reductions to tax positions of prior years	(0.2		)	(0.6		)
Balance at end of the period	$	0.3		$	0.4

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, 2017, the federal and Maryland statutes of limitation are closed with respect to all tax years through 2013, and the Kentucky statute of limitations is closed with respect to all tax years through 2012.

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 the years ended December 31, 2017 and 2016. Accrued interest and penalties for income taxes, included as a component of Other Long-Term Liabilities, totaled less than $0.1 million as of December 31, 2017, and $0.1 million as of December 31, 2016.

Net Income Per Share

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Net Income (Loss) Per Share

NET INCOME (LOSS) PER SHARE

Basic net income (loss) per common share is calculated by dividing income (loss) allocable to common stockholders by the weighted average number of shares of common stock outstanding during the period. In calculating diluted net income (loss) per common share, the number of shares is increased by the weighted average number of potential shares related to stock compensation awards. 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)	2017		2016

Net income (loss) allocable to common stockholders	$	5.3	$	(67.0	)

Average common shares outstanding - basic	9.1		9.1
Potentially dilutive shares related to stock options^(a)	—		—
Average common shares outstanding - diluted	9.1		9.1

Net income (loss) per common share – basic and diluted	$	0.58	$	(7.36	)

(a) Common stock equivalents related to stock options were less than 0.1 million shares for the year ended December 31, 2017. For the year ended December 31, 2016, common stock equivalents of less than 0.1 million shares are excluded from the diluted calculation as a result of the net loss.

Options outstanding and considered anti-dilutive as their exercise price exceeded the average share market price totaled 0.2 million in 2017 and 0.4 million in 2016.

Stockholders' Equity

12 Months Ended

Dec. 31, 2017

Stockholders' Equity Attributable to Parent [Abstract]

Stockholders' Equity Note Disclosure [Text Block]

STOCKHOLDERS’ EQUITY

Common Stock

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 9,038,751 shares of Common Stock, consisting of 7,632,669 shares of Class A Common Stock and 1,406,082 shares of Class B Common Stock.

A total of 38,751 shares of Class A Common Stock were issued in settlement of vested restricted stock units to three former members of the Board of Directors following the end of their service on May 31, 2017. Shares of Class B Common Stock that are sold in the market are automatically converted to shares of Class A Common Stock. In the twelve months ended December 31, 2017, a total of 30,318 shares of Class B Common Stock were sold in the market and converted to shares of Class A Common Stock as of December 31, 2017.

The Company has reserved 1,200,000 shares of Class A Common Stock under its management incentive plan, of which approximately 640,000 shares are available for future awards as of December 31, 2017. Refer to Note 12, Stock-Based Compensation, for additional information.

The Class A Common Stock trades under the symbol “LEU” on the NYSE American trading platform.

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.

Series B Preferred Stock

On February 14, 2017, Centrus issued 104,574 shares of Series B Preferred Stock as part of the securities exchange described in Note 9, Debt. The issuance of the Series B Preferred Stock was a non-cash financing transaction. The Series B Preferred Stock has a par value of $1.00 per share and a liquidation preference of $1,000 per share (the “Liquidation Preference”). The Series B Preferred Stock is recorded on the consolidated balance sheet at fair value less transaction costs, or $4.6 million as of the issuance date.

Holders of the Series B Preferred Stock are entitled to cumulative dividends at the rate of 7.5% per annum of the Liquidation Preference. Centrus is obligated to pay cash dividends on the Series B Preferred Stock in an amount equal to the Liquidation Preference to the extent that dividends are declared by the Board and:


(a)	its pension plans and Enrichment Corp.’s pension plans are at least 90% funded on a variable rate premium calculation in the current plan year;


(b)	its net income calculated in accordance with GAAP (excluding the effect of pension remeasurement) for the immediately preceding fiscal quarter exceeds $7.5 million;


(c)	its free cash flow (defined as the sum of cash provided by (used in) operating activities and cash provided by (used in) investing activities) for the immediately preceding four fiscal quarters exceeds $35 million;


(d)	the balance of cash and cash equivalents calculated in accordance with U.S. GAAP on the last day of the immediately preceding quarter would exceed $150 million after pro forma application of the dividend payment; and


(e)	dividends may be legally paid under Delaware law.

Centrus has not met these criteria for the periods from issuance through December 31, 2017, and has not declared, accrued or paid dividends on the Series B Preferred Stock as of December 31, 2017. Dividends on the Series B Preferred Stock are cumulative to the extent not paid at any quarter-end, whether or not declared and whether or not there are assets of the Company legally available for the payment of such dividends in whole or in part. As of December 31, 2017, the Series B Preferred Stock has an aggregate liquidation preference of $111.5 million, including accumulated undeclared dividends of $6.9 million.

Outstanding shares of the Series B Senior Preferred Stock are redeemable at the Company’s option, in whole or in part, for an amount of cash equal to the Liquidation Preference, plus an amount equal to the accrued and unpaid dividends, if any, whether or not declared, through date of redemption.

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, 2017, the Company had federal net operating losses of $789.7 million that currently expire through 2037.

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.

Effective on February 14, 2017, in connection with the settlement and completion of the exchange offer and consent solicitation, the Company amended the Rights Agreement solely to exclude acquisitions of the Series B Preferred Stock issued as part of the exchange offer and consent solicitation from the definition of “Common Shares.”

The Company’s stockholders approved the Rights Agreement at the 2017 annual meeting of stockholders on May 31, 2017. Unless earlier terminated in accordance with the Rights Agreement, the rights issued under the Rights Agreement expire on April 6, 2019.

Shares Outstanding

Changes in the number of shares outstanding follow:



	Preferred Stock, Series B	Common Stock, Class A	Common Stock, Class B

Balance at December 31, 2015	—	7,563,600	1,436,400
Issuance of Preferred Stock	—	—	—
Issuance of Class A Common Stock	—	—	—
Balance at December 31, 2016	—	7,563,600	1,436,400
Issuance of Preferred Stock	104,574	—	—
Issuance of Class A Common Stock	—	38,751	—
Conversion of Common Stock from Class B to Class A	—	30,318	(30,318	)
Balance at December 31, 2017	104,574	7,632,669	1,406,082

Commitments and Contingencies

12 Months Ended

Dec. 31, 2017

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 to 2026, in return for the purchase of additional SWU in those years. Depending on the total purchase obligations rescheduled to 2023 to 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.

American Centrifuge

Milestones Under the 2002 DOE-USEC Agreement

The Company 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 the Company’s 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 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 the Company’s 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 commenced with D&D of the Piketon facility in accordance with NRC requirements in the second quarter of 2016. Most of the D&D work has been completed as of December 31, 2017. The estimated fair value of the remaining costs to complete the D&D work, recorded as Decontamination and Decommissioning Obligations on the consolidated balance sheet, is $1.0 million as of December 31, 2017.

Centrus has previously provided financial assurance to the NRC for the D&D work in the form of surety bonds that are fully cash collateralized by Centrus for $16.1 million. Centrus expects to receive cash when surety bonds are reduced and/or cancelled as the Company fulfills its D&D obligations and the NRC license for the test facility is terminated. These deposits are included in Other Current Assets as of December 31, 2017, and Deposits for Surety Bonds, a noncurrent asset, as of December 31, 2016.

Centrus leases the Piketon facility from DOE. At the conclusion of the lease on June 30, 2019, without mutual agreement between Centrus and DOE regarding other possible uses for the facility, 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. As of December 31, 2017, the estimated cost for these lease termination obligations of $0.8 million is included in Accounts Payable and Accrued Liabilities on the consolidated balance sheet.

Centrus has previously provided financial assurance to DOE for the lease obligations in the form of surety bonds that are fully cash collateralized by Centrus for $13.5 million. Centrus expects to receive cash when surety bonds are reduced and/or cancelled as the Company fulfills its lease termination obligations. These deposits are included in Deposits for Surety Bonds as of December 31, 2017, and December 31, 2016.

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 $3.1 million in 2017 and $2.9 million in 2016. Future estimated minimum lease payments and expected lease administration payments follow (in millions):



2018	$	3.7
2019	1.7
2020	0.9
2021	0.9
2022	0.9
Thereafter	4.8
	$	12.9

Centrus has a lease with DOE for centrifuge testing facilities in Oak Ridge through December 2018. 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. In May 2017, Centrus entered into a lease through July 2021 for 6,000 square feet of additional office space in Waverly, Ohio. Centrus also has short-term leases for small areas of office space in Washington, DC, Tokyo, Japan and Paducah, Kentucky.

Segment Information

12 Months Ended

Dec. 31, 2017

Segment Reporting Information, Revenue for Reportable Segment [Abstract]

Segment Information

REVENUE BY GEOGRAPHIC AREA, MAJOR CUSTOMERS AND SEGMENT INFORMATION

Revenue by customer location, including customers in a foreign country representing 10% or more of total revenue, follows:



	Year Ended December 31,
($ millions)	2017		2016

United States	$	134.5	$	242.8
Foreign:
Japan	49.0		49.1
Belgium	34.9		—
Other	—		19.4
	83.9		68.5
Total revenue	$	218.4	$	311.3

In 2017, our 10 largest customers represented approximately 97% of total revenue and our four largest customers represented approximately 53% of total revenue. In our LEU segment, revenue from Synatom, Entergy, American Electric Power and South Carolina Electric & Gas represented approximately 16%, 14%, 12% and 11%, respectively, of total revenue in 2017. 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 our contract services segment, the U.S. government and its contractors represented approximately 11% of total revenue in 2017 and 12% of total revenue in 2016. No other customer represented more than 10% of total revenue in 2017 or 2016.

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 under a fixed price agreement as a contractor to UT-Battelle. The contract services segment also includes limited services provided by Centrus to DOE and its contractors at the Piketon facility. Gross profit is Centrus’ measure for segment reporting. There were no intersegment sales in the periods presented.

The Company’s revenue and gross profit by segment are as follows:



	Year Ended December 31,
($ millions)	2017			2016

Revenue
LEU segment:
Separative work units	$	195.4		$	258.5
Uranium	—			14.3
	195.4			272.8
Contract services segment	23.0			38.5
Revenue	$	218.4		$	311.3

Segment Gross Profit
LEU segment	$	59.3		$	38.5
Contract services segment	(2.5		)	6.6
Gross profit	$	56.8		$	45.1

The Company’s assets by segment are as follows:



	December 31,
($ millions)	2017		2016

Assets
LEU segment	$	657.4	$	686.0
Contract services segment	17.9		27.5
	$	675.3	$	713.5

Centrus’ long-term or long-lived assets, which include property, plant and equipment and other assets reported on the consolidated balance sheet, were located in the United States as of December 31, 2017, and December 31, 2016.

Subsequent Event (Notes)	12 Months Ended
Subsequent Event (Notes)	Dec. 31, 2017
Subsequent Event [Abstract]
Subsequent Event	SUBSEQUENT EVENT On January 11, 2018, the Company entered into a settlement agreement with DOE and the United States government regarding breach of contract claims relating to work performed by the Company under contracts with DOE and subcontracts with DOE contractors. As of December 31, 2017, the receivables balance related to the claims being settled is $14.5 million. Under the terms of the settlement agreement, DOE has agreed to settle all claims raised as part of and subsequent to the litigation for a total of $24.0 million and provide a complete close out of all such contracts and subcontracts settled under the settlement agreement without any further audit or review of the Company’s costs or incurred cost submissions. Under the settlement agreement, payment will be made by applying approximately $19.3 million of unapplied payments received from the United States government in prior years and the United States government making a cash payment of approximately $4.7 million. The Company has also agreed not to seek any additional payments under certain DOE subcontracts, as specified in the settlement agreement, for the periods of January 1, 2003, through September 30, 2017. The criteria to recognize additional revenues were satisfied at the time the settlement agreement was finalized and the Company expects to record revenues of approximately $9.5 million in the first quarter of 2018 related to the settlement. Certain claims, including, but not limited to, any claims relating to work performed under American Centrifuge project contracts after September 30, 2017, or any claims related to the Company’s subcontracts with UT-Battelle, for work at Oak Ridge National Laboratory, are excepted from the settlement agreement. Also excepted from the settlement agreement are the Company’s claims in its ongoing litigation with DOE relating to pension and postretirement benefit cost adjustments. Refer to Note 4, Receivables, for additional details.

Quarterly Results of Operations (Notes)

12 Months Ended

Dec. 31, 2017

Quarterly Results of Operations (Unaudited) [Abstract]

Quarterly Financial Information [Text Block]

QUARTERLY RESULTS OF OPERATIONS (Unaudited)

(in millions, except per share data)



	2017
	1st Qtr.			2nd Qtr.			3rd Qtr.			4th Qtr.			Year

Revenue	$	7.2		$	44.0		$	50.3		$	116.9		$	218.4
Cost of sales	9.7			48.3			38.7			64.9			161.6
Gross profit (loss)	(2.5		)	(4.3		)	11.6			52.0			56.8
Advanced technology license and decommissioning costs	6.1			4.4			4.5			0.7			15.7
Selling, general and administrative	12.4			9.7			11.0			10.0			43.1
Amortization of intangible assets	1.2			2.0			2.5			4.9			10.6
Special charges for workforce reductions and advisory costs	2.4			2.3			2.4			2.4			9.5
Gains on sales of assets	(1.0		)	(0.7		)	(0.6		)	(2.3		)	(4.6		)
Operating income (loss)	(23.6		)	(22.0		)	(8.2		)	36.3			(17.5		)
Gain on early extinguishment of debt	(33.6		)	—			—			—			(33.6		)
Interest expense	2.9			0.7			0.7			1.0			5.3
Investment income	(0.3		)	(0.3		)	(0.4		)	(0.3		)	(1.3		)
Income tax benefit (expense)	(0.2		)	—						0.1			(0.1		)
Net income (loss)	$	7.6		$	(22.4	)	$	(8.5	)	$	35.5		$	12.2
Preferred stock dividends - undeclared and cumulative	1.0			2.0			2.0			1.9			6.9
Net income (loss) allocable to common stockholders	$	6.6		$	(24.4	)	$	(10.5	)	$	33.6		$	5.3

Net income (loss) per share:
Basic	$	0.73		$	(2.69	)	$	(1.15	)	$	3.69		$	0.58
Diluted	$	0.72		$	(2.69	)	$	(1.15	)	$	3.69		$	0.58



	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	—			0.6			0.6			0.2			1.4
Gains on sales of assets	(0.3		)	(0.4		)	(0.3		)	(0.2		)	(1.2		)
Operating income (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		)
Income tax benefit	(0.6		)	—			—			—			(0.6		)
Net loss	$	(14.6	)	$	(2.9	)	$	(41.3	)	$	(8.2	)	$	(67.0	)
Preferred stock dividends - undeclared and cumulative	—			—			—			—			—
Net loss allocable to common stockholders	$	(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	)

The calculation of net income (loss) per share on a dilutive basis is provided in Note 14, Net Income (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 options or convertible securities is anti-dilutive.

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2017
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”). 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 Low-enriched uranium (“LEU”) consists of two components: separative work units (“SWU”) and uranium. SWU is a standard unit of measurement that represents the effort required to transform a given amount of natural uranium into two components: enriched uranium having a higher percentage of U²³⁵ and depleted uranium having a lower percentage of U²³⁵. The SWU contained in LEU is calculated using an industry standard formula based on the physics of enrichment. The amount of enrichment deemed to be contained in LEU under this formula is commonly referred to as its SWU component and the quantity of natural uranium deemed to be used in the production of LEU under this formula is referred to as its uranium 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 all, or some portion, 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 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. Refer also to Carrying Value of Long-Lived Assets below.
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’ 8.0% paid-in-kind (“PIK”) toggle notes (the “8.0% PIK Toggle Notes”) and its 8.25% notes (the “8.25% Notes”) are recorded at face value and the fair value is disclosed. The estimated fair value of each of the 8.0% PIK Toggle Notes and the 8.25% Notes is based on the trading price nearest the balance sheet date observed on secondary markets. 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. Utility customers in general have the option to defer physical receipt of LEU or uranium purchased from us beyond the contractual sale period. In such cases, title to LEU or uranium is transferred to the customer and an obligation for Centrus is created and a receivable is recorded. Cash is collected for the receivable under normal credit terms. The obligation is included in Deferred Revenue and Advances from Customers on the consolidated balance sheet and the customer-titled product is classified as Deferred Costs Associated with Deferred Revenue. Risk of loss remains with Centrus until physical delivery occurs. The recognition of revenue and related cost of sales occurs at the time physical delivery occurs and risk of loss transfers to the customer, which may occur beyond one year. The timing of physical delivery, subject to notice period requirements, is at the option of the customer. As such, deferred costs and deferred revenue are classified within current assets and current liabilities, respectively. 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 contracts with UT-Battelle provide for fixed payments for monthly reports or for fixed payments upon completion of milestones. For contracts that provide fixed payments for monthly reports, revenue is recognized as deliverables are completed and as fees are earned. For contracts that provide fixed payments for completion of milestones, revenue is recognized as each milestone is completed. Centrus and DOE have yet to fully settle the Company’s claims for reimbursements for certain pension and postretirement benefits costs related to past contract work performed at the Portsmouth and Paducah sites. There is the potential for additional revenue to be recognized for this work pending the outcome of legal proceedings related to the Company’s claims for payment and the potential release of previously established valuation allowances on receivables.
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 NRC requirements. 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 has determined that this standard will not have a material impact on its financial position or results of operations. The Company adopted FASB ASU No. 2014-09 on January 1, 2018 using the modified retrospective method. 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 became 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 adoption of ASU 2016-09 did not 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, and is to be applied retrospectively. Under the retrospective transition, transaction costs of $9.0 million incurred in the three months ended March 31, 2017, related to the February 14, 2017, securities exchange described in Note 9, Debt, will be reclassified from cash used in operating activities to cash used in financing activities. 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. 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. The provisions of ASU 2016-18 are not expected to have a material impact on the Company’s consolidated financial statements. In March 2017, the FASB issued ASU 2017-07, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. ASU 2017-07 requires the service cost component of net periodic benefit costs be presented with other employee compensation costs and other components of net periodic benefit costs to be presented outside of any subtotal of operating income. In addition, only the service cost component of net periodic benefit costs is eligible for capitalization in assets when applicable. ASU 2017-07 will become effective for the Company beginning in the first quarter of 2018. The provisions of ASU 2017-17 related to the presentation of the components of net periodic benefit costs are to be applied retrospectively. Annual net periodic benefit costs (credits) of ($26.5 million) and ($0.7 million) for 2017 will be reclassified from cost of sales and selling, general and administrative (SG&A) expense, respectively, to other nonoperating income in the consolidated statement of operations. The provision of ASU 2017-17 allowing only the service cost component of net periodic benefit costs to be capitalized will be adopted on a prospective basis and is not expected to have a significant impact on the Company’s consolidated financial statements as no portion of net periodic benefit costs were capitalized in assets during 2017. In February 2018, the FASB issued ASU 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. ASU 2018-02 allows a reclassification from accumulated other comprehensive income to retained earnings for the tax effects of items within accumulated other comprehensive income (stranded tax effects) resulting from the decrease in the corporate income tax rate reflected in the December 2017 Tax Cuts and Jobs Act. The provisions of ASU 2018-02 are effective for all fiscal years beginning after December 15, 2018 and interim periods within those years. Early adoption is permitted. The Company is evaluating the effects that ASU 2018-02 will have its consolidated financial statements.

Special Charges Special Charges (Tables)

12 Months Ended

Dec. 31, 2017

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, 2015		2016					Liability Dec. 31, 2016		2017					Liability Dec. 31, 2017
	Liability Dec. 31, 2015		Charges for Termination Benefits		Paid			Liability Dec. 31, 2016		Charges for Termination Benefits		Paid/ Settled			Liability Dec. 31, 2017
Workforce reductions:
Evolving business needs	$	0.3	$	0.3	$	(0.5	)	$	0.1	$	2.4	$	(1.7	)	$	0.8
Piketon demonstration facility	8.4		0.1		(3.1		)	5.4		1.1		(0.8		)	5.7
	$	8.7	$	0.4	$	(3.6	)	$	5.5	$	3.5	$	(2.5	)	$	6.5

Inventories (Tables)

12 Months Ended

Dec. 31, 2017

Inventory, Net [Abstract]

Schedule of Inventories



	December 31, 2017						December 31, 2016
( in millions)	Current Assets		Current Liabilities (a)		Inventories, Net		Current Assets		Current Liabilities (a)		Inventories, Net

Separative work units	$	47.2	$	15.0	$	32.2	$	115.8	$	15.2	$	100.6
Uranium	105.9		62.9		43.0		61.4		42.3		19.1
Materials and supplies	—		—		—		0.2		—		0.2
	$	153.1	$	77.9	$	75.2	$	177.4	$	57.5	$	119.9


(a)	Inventories owed to customers and suppliers, included in current liabilities, include SWU and uranium inventories owed to fabricators that process LEU into fuel for use in nuclear reactors.

Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

A summary of changes in property, plant and equipment follows (in millions):



	December 31, 2016			Additions / (Depreciation)			Retirements			December 31, 2017
Land	$	1.2		$	—		$	—		$	1.2
Leasehold improvements	3.0			0.2			—			3.2
Machinery and equipment	1.7			0.1			(0.5		)	1.3
Other	0.9			0.2			—			1.1
Property, plant and equipment, gross	6.8			0.5			(0.5		)	6.8
Accumulated depreciation	(0.8		)	(1.4		)	0.3			(1.9		)
Property, plant and equipment, net	$	6.0		$	(0.9	)	$	(0.2	)	$	4.9

Assets and Property Sold [Table Text Block]

The Company sold assets and property in 2017 and 2016 related to its operations and the American Centrifuge project that were no longer needed (in millions):



	Year Ended December 31,
	2017			2016
Sales of assets and property, net of auction fees and other costs	$	4.8		$	1.2
Less: net carrying value	(0.2		)	—
Gain on sales of assets	$	4.6		$	1.2

Cash proceeds received	$	4.7		$	1.5

Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Intangible Assets and Excess Reorganization Value [Table Text Block]



( in millions)	December 31, 2017						December 31, 2016
	Gross Carrying Amount		Accumulated Amortization		Net Amount		Gross Carrying Amount		Accumulated Amortization		Net Amount
Sales order book	$	54.6	$	25.9	$	28.7	$	54.6	$	19.9	$	34.7
Customer relationships	68.9		14.9		54.0		68.9		10.3		58.6
Total	$	123.5	$	40.8	$	82.7	$	123.5	$	30.2	$	93.3

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):



2018	$	8.1
2019	7.1
2020	10.3
2021	8.9
2022	9.0
Thereafter	39.3
Total	$	82.7

Pension and Postretirement Health and Life Benefits (Tables)

12 Months Ended

Dec. 31, 2017

Retirement Benefits, Description [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:



	Defined Benefit Pension Plans						Postretirement Health and Life Benefit Plans
($ millions)	Year Ended December 31,						Year Ended December 31,
	2017			2016			2017			2016
Changes in Benefit Obligations:
Obligations at beginning of period	$	814.6		$	832.8		$	192.8		$	203.5
Actuarial (gains) losses, net	32.8			19.1			(24.8		)	(9.2		)
Service costs	3.7			3.8			—			—
Interest costs	32.2			35.4			7.2			8.2
Benefits paid	(59.3		)	(60.9		)	(14.5		)	(13.3		)
Lump sum benefits paid	(2.9		)	(12.2		)	—			—
Plan change	—			—			10.0			3.6
Administrative expenses paid	(3.2		)	(3.4		)	—			—
Obligations at end of period	817.9			814.6			170.7			192.8
Changes in Plan Assets:
Fair value of plan assets at beginning of period	634.1			656.3			7.7			13.8
Actual return on plan assets	84.4			50.2			0.1			0.5
Company contributions	1.5			4.1			8.5			6.7
Benefits paid	(59.3		)	(60.9		)	(14.5		)	(13.3		)
Lump sum benefits paid	(2.9		)	(12.2		)	—			—
Administrative expenses paid	(3.2		)	(3.4		)	—			—
Fair value of plan assets at end of period	654.6			634.1			1.8			7.7
Unfunded status at end of period	$	(163.3	)	$	(180.5	)	$	(168.9	)	$	(185.1	)

Amounts recognized in assets and liabilities:
Current liabilities	$	(1.7	)	$	(0.6	)	(14.7		)	(13.8		)
Noncurrent liabilities	(161.6		)	(179.9		)	(154.2		)	(171.3		)
	$	(163.3	)	$	(180.5	)	$	(168.9	)	$	(185.1	)
Amounts in accumulated other comprehensive income (loss), pre-tax:
Prior service cost (credit)	$	—		$	—		$	(2.5	)	$	(2.6	)

Discount rate used to determine benefit obligations at end of period:	3.7		%	4.1		%	3.6		%	3.9		%

Schedule of Net Benefit Costs [Table Text Block]

Components of Net Periodic Benefit Costs and Other Amounts Recognized in Other Comprehensive Income (Loss)

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.



	Defined Benefit Pension Plans						Postretirement Health and Life Benefit Plans
($ millions)	Year Ended December 31,						Year Ended December 31,
	2017			2016			2017			2016
Net Periodic Benefit (Credits) Costs
Service costs	$	3.7		$	3.8		$	—		$	—
Interest costs	32.2			35.4			7.2			8.2
Expected return on plan assets (gains)	(40.7		)	(42.0		)	—			(0.3		)
Amortization of prior service costs (credits), net	—			—			(0.1		)	(0.3		)
Actuarial (gains) losses, net	(10.9		)	10.9			(24.9		)	(9.5		)
Loss on plan changes resulting from a pending legal settlement	—			—			10.0			—
Net periodic benefit (credits) costs	$	(15.7	)	$	8.1		$	(7.8	)	$	(1.9	)



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	—			—		0.1			0.3
Total loss recognized in other comprehensive income (loss), pre-tax	$	—		$	—	$	0.1		$	3.9
Total recognized in net periodic benefit costs (income) and other comprehensive income (loss), pre-tax	$	(15.7	)	$	8.1	$	(7.7	)	$	2.0

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,
	2017	2016	2017	2016
Discount rate	3.7%	4.1%	3.6%	3.9%
Expected return on plan assets	6.8%	6.8%	—	5.0%

Schedule of Health Care Cost Trend Rates [Table Text Block]

Healthcare cost trend rates used to measure postretirement health benefit obligations follow:



	December 31,
	2017	2016
Healthcare cost trend rate for the following year	6.5%	7.0%
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 as follows:



(in millions)	One-Percentage Point
	Increase		Decrease
Postretirement health benefit obligation	$	3.7	$	(3.4	)
Net periodic benefit costs (service and interest cost components only)	$	0.2	$	(0.1	)

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 for the defined benefit pension plans follows:



	December 31,
	2017		2016		2018 Target
Equity securities	49	%	41	%	40	-	60%
Debt securities	51		59		40	-	60
	100	%	100	%



	Defined Benefit Pension Plans
(in millions)	Level 1				Level 2				Level 3				Total
	2017		2016		2017		2016		2017		2016		2017			2016
U.S. government securities	$	—	$	—	$	34.6	$	84.7	$	—	$	—	$	34.6		$	84.7
Corporate debt	—		—		119.7		217.0		—		—		119.7			217.0
Municipal bonds and non-U.S. government securities	—		—		3.5		6.2		—		—		3.5			6.2
Mortgage and asset backed securities	—		—		0.3		5.4		—		—		0.3			5.4
Fair value of investments by hierarchy level	$	—	$	—	$	158.1	$	313.3	$	—	$	—	$	158.1		$	313.3
Investments measured at NAV (a)													494.7			318.3
Accrued interest receivable													1.9			3.5
Unsettled transactions													(0.1		)	(1.0		)
Plan assets													$	654.6		$	634.1



	Postretirement Health and Life Benefit Plans
(in millions)	Level 1				Level 2				Level 3				Total
	2017		2016		2017		2016		2017		2016		2017		2016
Money market funds	$	—	$	0.2	$	—	$	—	$	—	$	—	$	—	$	0.2
Bond mutual funds	1.8		7.5		—		—		—		—		1.8		7.5
Equity mutual funds	—		—		—		—		—		—		—		—
Fair value of investments by hierarchy level	$	1.8	$	7.7	$	—	$	—	$	—	$	—	$	1.8	$	7.7

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
2018	$	59.9	$	16.4
2019	58.2		15.2
2020	56.1		14.2
2021	54.9		13.4
2022	53.7		12.8
2023 to 2027	251.8		53.1

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

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,
	2017		2016

Total stock-based compensation costs:
Restricted stock units	$	0.1	$	0.2
Stock options	0.4		0.3
Expense included in selling, general and administrative expense	$	0.5	$	0.5

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. There were no option grants in the year ended December 31, 2017.



	Year Ended December 31, 2016

Options granted (in thousands)	15
Risk-free interest rate	1.91%
Expected volatility	75%
Expected option life (years)	6
Weighted-average grant date fair value	$1.77

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, 2016	483	$4.02	8.4	$1.1
Granted	—	—
Exercised	—	—
Forfeited/Cancelled	(58)	$3.12
Outstanding at December 31, 2017	425	$4.14	7.3	$0.1
Exercisable at December 31, 2017	236	$4.17	7.3	$0.1

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, 2017, follow:



Stock Exercise Price	Options Outstanding (thousands)	Weighted Average Remaining Contractual Life in Years	Options Exercisable (thousands)

$5.62	22	6.9	22
$4.37	300	7.2	150
$3.90	23	7.6	15
$3.93	15	7.6	10
$2.71	50	7.8	34
$2.68	15	8.5	5

Income Taxes Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

The benefit from income taxes from continuing operations is as follows (in millions):



	Year Ended December 31,
	2017			2016
Current:
Federal	$	—		$	—
State and local	(0.1		)	(0.6		)
Foreign	—			—
	(0.1		)	(0.6		)
Deferred:
Federal	—			—
State and local	—			—
Foreign	—			—
	—			—
	$	(0.1	)	$	(0.6	)

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]



	December 31,
	2017			2016
Deferred tax assets:
Employee benefits costs	$	79.9		$	142.3
Inventory	2.4			—
Property, plant and equipment	187.0			318.8
Net operating loss and credit carryforwards	166.9			254.9
Accrued expenses	0.9			7.9
Long-term debt and financing costs	17.3			8.0
Other	5.5			8.6
	459.9			740.5
Valuation allowance	(440.7		)	(702.2		)
Deferred tax assets, net of valuation allowance	$	19.2		$	38.3

Deferred tax liabilities:
Inventory	$	—		$	2.6
Intangible assets	17.7			33.0
Prepaid expenses	1.5			2.7
Deferred tax liabilities	$	19.2		$	38.3
	$	—		$	—

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,
	2017		2016
Federal statutory tax rate	35	%	35	%
Gain on early extinguishment of debt	(268	)	6
Tax Cuts and Jobs Act of 2017	2,382		—
Interest expense	4		(3	)
Other non-deductible expenses	1		—
Valuation allowance against net deferred tax assets	(2,156	)	(36	)
State income tax expense, net of federal benefit	1		(1	)
Effective tax rate	(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,
	2017			2016
Balance at beginning of the period	$	0.4		$	1.0
Additions to tax positions of current period	0.1			—
Reductions to tax positions of prior years	(0.2		)	(0.6		)
Balance at end of the period	$	0.3		$	0.4

Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2017

Stockholders' Equity Attributable to Parent [Abstract]

Schedule of Stock by Class [Table Text Block]

Changes in the number of shares outstanding follow:



	Preferred Stock, Series B	Common Stock, Class A	Common Stock, Class B

Balance at December 31, 2015	—	7,563,600	1,436,400
Issuance of Preferred Stock	—	—	—
Issuance of Class A Common Stock	—	—	—
Balance at December 31, 2016	—	7,563,600	1,436,400
Issuance of Preferred Stock	104,574	—	—
Issuance of Class A Common Stock	—	38,751	—
Conversion of Common Stock from Class B to Class A	—	30,318	(30,318	)
Balance at December 31, 2017	104,574	7,632,669	1,406,082

- Definition

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21506-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=65877616&loc=d3e177068-122764

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(d))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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+ Details

Segment Information (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting Information, Revenue for Reportable Segment [Abstract]

Segment Reporting Information



	Year Ended December 31,
($ millions)	2017			2016

Revenue
LEU segment:
Separative work units	$	195.4		$	258.5
Uranium	—			14.3
	195.4			272.8
Contract services segment	23.0			38.5
Revenue	$	218.4		$	311.3

Segment Gross Profit
LEU segment	$	59.3		$	38.5
Contract services segment	(2.5		)	6.6
Gross profit	$	56.8		$	45.1

Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Table Text Block]

Revenue by customer location, including customers in a foreign country representing 10% or more of total revenue, follows:



	Year Ended December 31,
($ millions)	2017		2016

United States	$	134.5	$	242.8
Foreign:
Japan	49.0		49.1
Belgium	34.9		—
Other	—		19.4
	83.9		68.5
Total revenue	$	218.4	$	311.3

Quarterly Results of Operations (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Results of Operations (Unaudited) [Abstract]

Schedule of Quarterly Financial Information [Table Text Block]



	2017
	1st Qtr.			2nd Qtr.			3rd Qtr.			4th Qtr.			Year

Revenue	$	7.2		$	44.0		$	50.3		$	116.9		$	218.4
Cost of sales	9.7			48.3			38.7			64.9			161.6
Gross profit (loss)	(2.5		)	(4.3		)	11.6			52.0			56.8
Advanced technology license and decommissioning costs	6.1			4.4			4.5			0.7			15.7
Selling, general and administrative	12.4			9.7			11.0			10.0			43.1
Amortization of intangible assets	1.2			2.0			2.5			4.9			10.6
Special charges for workforce reductions and advisory costs	2.4			2.3			2.4			2.4			9.5
Gains on sales of assets	(1.0		)	(0.7		)	(0.6		)	(2.3		)	(4.6		)
Operating income (loss)	(23.6		)	(22.0		)	(8.2		)	36.3			(17.5		)
Gain on early extinguishment of debt	(33.6		)	—			—			—			(33.6		)
Interest expense	2.9			0.7			0.7			1.0			5.3
Investment income	(0.3		)	(0.3		)	(0.4		)	(0.3		)	(1.3		)
Income tax benefit (expense)	(0.2		)	—						0.1			(0.1		)
Net income (loss)	$	7.6		$	(22.4	)	$	(8.5	)	$	35.5		$	12.2
Preferred stock dividends - undeclared and cumulative	1.0			2.0			2.0			1.9			6.9
Net income (loss) allocable to common stockholders	$	6.6		$	(24.4	)	$	(10.5	)	$	33.6		$	5.3

Net income (loss) per share:
Basic	$	0.73		$	(2.69	)	$	(1.15	)	$	3.69		$	0.58
Diluted	$	0.72		$	(2.69	)	$	(1.15	)	$	3.69		$	0.58



	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	—			0.6			0.6			0.2			1.4
Gains on sales of assets	(0.3		)	(0.4		)	(0.3		)	(0.2		)	(1.2		)
Operating income (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		)
Income tax benefit	(0.6		)	—			—			—			(0.6		)
Net loss	$	(14.6	)	$	(2.9	)	$	(41.3	)	$	(8.2	)	$	(67.0	)
Preferred stock dividends - undeclared and cumulative	—			—			—			—			—
Net loss allocable to common stockholders	$	(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	)

Special Charges (Schedule of Restructuring and Related Costs)(Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Restructuring liability				$ 5.5				$ 8.7	$ 5.5	$ 8.7
Termination benefit costs									3.5	0.4
Payments for one-time termination benefits									(2.5)	(3.6)
Restructuring liability	$ 6.5				$ 5.5				6.5	5.5
Special charges for workforce reductions	2.4	$ 2.4	$ 2.3	2.4	0.2	$ 0.6	$ 0.6	0.0	9.5	1.4
Contract Termination [Member]
Restructuring liability				5.4				8.4	5.4	8.4
Termination benefit costs									1.1	0.1
Payments for one-time termination benefits									(0.8)	(3.1)
Restructuring liability	5.7				5.4				5.7	5.4
Other Restructuring [Member]
Restructuring liability				$ 0.1				$ 0.3	0.1	0.3
Termination benefit costs									2.4	0.3
Payments for one-time termination benefits									(1.7)	(0.5)
Restructuring liability	$ 0.8				$ 0.1				$ 0.8	$ 0.1

Special Charges (Narrative)(Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Actuarial (gain) loss from remeasurement, net									$ 25.8	$ (1.4)
Termination benefit costs									3.5	0.4
Other restructuring costs									6.3	1.0
Payments for Restructuring									(2.5)	(3.6)
Restructuring Reserve	$ 6.5				$ 5.5				6.5	5.5	$ 8.7
Restructuring Reserve, Current	3.1								3.1
Restructuring Reserve, Noncurrent	2.6								2.6
Restructuring Charges	2.4	$ 2.4	$ 2.3	$ 2.4	0.2	$ 0.6	$ 0.6	$ 0.0	9.5	1.4
Contract Termination [Member]
Termination benefit costs									1.1	0.1
Payments for Restructuring									(0.8)	(3.1)
Restructuring Reserve	5.7				5.4				5.7	5.4	8.4
Other Restructuring [Member]
Termination benefit costs									2.4	0.3
Payments for Restructuring									(1.7)	(0.5)
Restructuring Reserve	$ 0.8				$ 0.1				$ 0.8	$ 0.1	$ 0.3

Contract Services and Advanced Technology License and Decommissioning Costs (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2017	Mar. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Contract revenue current work					$ 30.4
Contract revenue past work					8.1
D&D Expense	$ 5.9	$ (7.0)			$ (19.0)
Decontamination and decommissioning obligations - total	$ 1.0
2018 ORNL Contract [Member] \| Scenario, Forecast [Member]
Contract value			$ 16.0
2017 ORNL Contract [Member]
Contract value				$ 25.0
Contract monthly revenue				2.0
Contract milestone payments				$ 1.0
2016 ORNL Contract [Member]
Contract monthly revenue						$ 2.7

Accounts Receivable (Schedule of Accounts Receivable) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounts Receivable, Net, Current [Abstract]
Utility Customer Receivables	$ 42.3	$ 15.3
Contract Services Customer Receivables	17.9	4.6
Accounts Receivable, Net	$ 60.2	$ 19.9

Accounts Receivable (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net		$ 60.2	$ 19.9
Customer Advances, Current		19.3
Government [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net		14.5
Customer Advances, Current		19.3
Government [Member] \| Scenario, Forecast [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Litigation Settlement, Amount Awarded from Other Party	$ 24.0
Proceeds on claims	$ 4.7
Government - portion related to retiree benefits [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Noncurrent		$ 42.8

Inventories (Schedule of Inventories) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Inventory, Net [Abstract]
Separative work units inventory	$ 47.2	$ 115.8
Uranium inventory	105.9	61.4
Materials and supplies	0.0	0.2
Inventories	153.1	177.4
Separative work units owed to customers and suppliers	15.0	15.2
Uranium owed to customers and suppliers	62.9	42.3
Inventories owed to customers and suppliers	77.9	57.5
Separative work units net of liability	32.2	100.6
Uranium inventory net of liability	43.0	19.1
Inventories, net	$ 75.2	$ 119.9

Property, Plant and Equipment (Tables) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 6.8	$ 6.8
Property, Plant and Equipment, Additions	0.5
Property, Plant and Equipment, Disposals	(0.5)
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(1.9)	(0.8)
Depreciation	(1.4)	(0.6)
Accumulated Depreciation, Depletion and Amortization, Sale or Disposal of Property, Plant and Equipment	0.3
Net carrying value of assets retired	(0.2)
Property, Plant And Equipment, Net Capital Expenditures	(0.9)
Property, Plant and Equipment, Net	4.9	6.0
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	3.2	3.0
Property, Plant and Equipment, Additions	0.2
Property, Plant and Equipment, Disposals	0.0
Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1.3	1.7
Property, Plant and Equipment, Additions	0.1
Property, Plant and Equipment, Disposals	(0.5)
Other Capitalized Property Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1.1	$ 0.9
Property, Plant and Equipment, Additions	$ 0.2

Property, Plant and Equipment (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Depreciation	$ 1.4	$ 0.6
Sale price assets and property, net	4.8	1.2
Net carrying value of assets retired	0.2
Gain on sales of assets	4.6	1.2
Proceeds from sale of assets and property	4.7	1.5
Sale proceeds included in accounts receivable	$ 0.2	$ 0.1

Intangible Assets Schedule of Intangible Assets and Excess Reorganization Value (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	$ 123.5	$ 123.5
Accumulated intangible asset amortization	(40.8)	(30.2)
Amortizable intangible assets, net	$ 82.7	93.3
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	(25.9)	(19.9)
Amortizable intangible assets, net	28.7	34.7
Customer-Related Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	68.9	68.9
Accumulated intangible asset amortization	(14.9)	(10.3)
Amortizable intangible assets, net	$ 54.0	$ 58.6

Intangible Assets Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity (Details) $ in Millions	Dec. 31, 2017 USD ($)
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	$ 8.1
Finite-Lived Intangible Assets, Amortization Expense, Year Two	7.1
Finite-Lived Intangible Assets, Amortization Expense, Year Three	10.3
Finite-Lived Intangible Assets, Amortization Expense, Year Four	8.9
Finite-Lived Intangible Assets, Amortization Expense, Year Five	9.0
Finite-Lived Intangible Assets, Amortization Expense, after Year Five	39.3
Finite-Lived Intangible Assets, Net	$ 82.7

Accounts Payable and Accrued Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Trade payables	$ 6.3	$ 11.5
Compensation and benefits payable	17.4	12.5
Postretirement health and life benefit obligations - current	14.7	13.8
Accrued severance payments	3.9	3.4
Current portion of interest on 8.25% Notes	6.1	0.0
Accrued interest on PIK Toggle Notes (cash portion)	0.2	1.5
Other accrued liabilities	4.7	3.7
Accounts payable and accrued liabilities	$ 53.3	$ 46.4

Debt Schedule of Debt (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Long-term debt, carrying amount	$ 163.7	$ 234.6
Deferred issuance costs	0.1	0.5
Long-term debt, current and noncurrent	163.6	234.1
Long-term debt, current	6.1	0.0
Long-term debt	157.5	234.1
Senior Notes [Member]
Debt Instrument [Line Items]
Long-term debt, face amount	74.3
Long-term debt, interest	58.1
Long-term debt, carrying amount	132.4
Debt Instrument Carrying Amount Current and Noncurrent	132.4
Payment in Kind (PIK) Note [Member]
Debt Instrument [Line Items]
Debt Instrument Carrying Amount Current and Noncurrent	$ 31.3	$ 234.6

Debt (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Preferred stock, shares issued		104,574
Preferred stock, liquidation preference per share		$ 1,000
Cash paid in exchange	$ 27.6
Long-term debt, carrying amount		$ 163.7	$ 234.6
Gain on early extinguishment of debt	33.6	33.6	16.7
Transaction costs	9.0
Write off of deferred financing cost	0.4
Long-term debt, current		6.1	0.0
Subordination to credit facility, facility total		50.0
Subordination to credit facility, facility maximum net borrowing		40.0
Interest payable, cash portion		$ 0.2	1.5
Payment in Kind (PIK) Note [Member]
Repurchase of debt	$ 204.9
Debt instrument interest rate		5.50%
Interest payable		$ 0.6	4.7
Interest payable, cash portion		0.2	1.5
Interest payable, PIK portion		$ 0.4	$ 3.2
Senior Notes [Member]
Debt instrument interest rate		8.25%
Long-term debt, face amount		$ 74.3
Long-term debt, carrying amount		$ 132.4

Fair Value Measurements (Financial Instruments Recorded at Fair Value) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Cash and cash equivalents	$ 208.8	$ 260.7
Deferred compensation asset	1.4	1.1
Deferred compensation obligation	1.4	1.1
Level 1 [Member]
Deferred compensation asset	1.4	1.1
Deferred compensation obligation	$ 1.4	$ 1.1

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, carrying value	$ 132.4
Long-term debt, fair value	61.7
Long-term debt, face amount	74.3
Payment in Kind (PIK) Note [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, carrying value	31.3	$ 234.6
Long-term debt, fair value	$ 25.1	$ 107.4

Pension and Postretirement Health and Life Benefits (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Actuarial (gain) loss from remeasurement, net		$ 25.8	$ (1.4)
Defined Contribution Plan, Cost		2.3	2.4
Scenario, Forecast [Member]
Expected defined benefit plan contributions for next fiscal year for qualified plans	$ 12.8
Expected defined benefit plan contributions for next fiscal year for non-qualified plans	1.8
Expected defined benefit plan contributions for next fiscal year for postretirement health and life benefit plans	$ 14.6
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Accumulated Benefit Obligation		817.9	814.6
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)		$ (15.7)	8.1
Approximate Number of Plan Participants		5,000
Defined Benefit Plan, Plan Assets, Contributions by Employer		$ 1.5	4.1
Actuarial (gain) loss from remeasurement, net		$ 32.8	$ 19.1
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		3.70%	4.10%
Defined Benefit Plan, Expected Return (Loss) on Plan Assets		$ 40.7	$ 42.0
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)		$ (7.8)	(1.9)
Approximate Number of Plan Participants		3,100
Defined Benefit Plan, Plan Assets, Contributions by Employer		$ 8.5	6.7
Actuarial (gain) loss from remeasurement, net		$ (24.8)	$ (9.2)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		3.60%	3.90%
Defined Benefit Plan, Expected Return (Loss) on Plan Assets		$ 0.0	$ 0.3

Pension and Postretirement Health and Life Benefits (Schedule of Changes in Projected Benefit Obligations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Actuarial (gain) loss from remeasurement, net	$ 25.8	$ (1.4)
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Benefit Obligation	817.9	814.6	$ 832.8
Actuarial (gain) loss from remeasurement, net	32.8	19.1
Defined Benefit Plan, Service Cost	3.7	3.8
Defined Benefit Plan, Interest Cost	32.2	35.4
Defined Benefit Plan, Benefit Obligation, Benefits Paid	59.3	60.9
Defined Benefit Plan, Lump Sum Benefits Paid	(2.9)	(12.2)
Defined Benefit Plan, Administrative Expenses Paid	(3.2)	(3.4)
Defined Benefit Plan, Fair Value of Plan Assets	654.6	634.1	656.3
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	84.4	50.2
Defined Benefit Plan, Plan Assets, Contributions by Employer	1.5	4.1
Defined Benefit Plan, Plan Assets, Benefits Paid	59.3	60.9
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(163.3)	(180.5)
Amounts Recognized In Current Liabilities	(1.7)	(0.6)
Amounts Recognized In Noncurrent Liabilities	(161.6)	(179.9)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	$ (163.3)	$ (180.5)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	3.70%	4.10%
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan, Benefit Obligation	$ 170.7	$ 192.8	203.5
Actuarial (gain) loss from remeasurement, net	(24.8)	(9.2)
Defined Benefit Plan, Service Cost	0.0	0.0
Defined Benefit Plan, Interest Cost	7.2	8.2
Defined Benefit Plan, Benefit Obligation, Benefits Paid	14.5	13.3
Defined Benefit Plan, Lump Sum Benefits Paid	0.0	0.0
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	10.0	3.6
Defined Benefit Plan, Administrative Expenses Paid	0.0
Defined Benefit Plan, Fair Value of Plan Assets	1.8	7.7	$ 13.8
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	0.1	0.5
Defined Benefit Plan, Plan Assets, Contributions by Employer	8.5	6.7
Defined Benefit Plan, Plan Assets, Benefits Paid	14.5	13.3
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(168.9)	(185.1)
Amounts Recognized In Current Liabilities	(14.7)	(13.8)
Amounts Recognized In Noncurrent Liabilities	(154.2)	(171.3)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(168.9)	(185.1)
Recognized In Accumulated Other Comprehensive Income Pre Tax Prior Service Cost Credit	$ (2.5)	$ (2.6)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	3.60%	3.90%

Pension and Postretirement Health and Life Benefits (Schedule of Net Benefit Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Actuarial (gain) loss from remeasurement, net	$ (25.8)	$ 1.4
Pension Plan, Defined Benefit [Member]
Service costs	3.7	3.8
Interest costs	32.2	35.4
Expected return on plan assets (gains)	(40.7)	(42.0)
Amortization of actuarial (gains) losses, net	(10.9)	10.9
Actuarial (gain) loss from remeasurement, net	(32.8)	(19.1)
Net periodic benefit cost (credit)	(15.7)	8.1
Postretirement Health and Life Benefits Plans [Member]
Service costs	0.0	0.0
Interest costs	7.2	8.2
Expected return on plan assets (gains)	0.0	(0.3)
Amortization of actuarial (gains) losses, net	(24.9)	(9.5)
Amortization of prior service costs (credits), net	0.1	0.3
Actuarial (gain) loss from remeasurement, net	24.8	9.2
Loss on plan changes resulting from a pending legal settlement	10.0
Net periodic benefit cost (credit)	$ (7.8)	$ (1.9)

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, 2017	Dec. 31, 2016
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	$ (0.1)	$ (0.3)
Pension Plan, Defined Benefit [Member]
Total recognized in net periodic benefit costs (income) and other comprehensive income (loss), pre-tax	(15.7)	8.1
Other Postretirement Benefit Plan, Defined Benefit [Member]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), after Reclassification Adjustment, before Tax	0.0
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	0.1
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	0.1	3.9
Total recognized in net periodic benefit costs (income) and other comprehensive income (loss), pre-tax	$ (7.7)	$ 2.0

Pension and Postretirement Health and Life Benefits (Schedule of Assumptions Used) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	3.70%	4.10%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	6.80%	6.80%
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	3.60%	3.90%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets		5.00%

Pension and Postretirement Health and Life Benefits (Schedule of Healthcare Cost Trend Rates) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year	6.50%	7.00%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate	5.00%	5.00%
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate	2021

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, 2017 USD ($)
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rate [Abstract]
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation	$ 3.7
Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation	(3.4)
Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components	0.2
Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components	$ (0.1)

Pension and Postretirement Health and Life Benefits (Plan Asset Allocations) (Details) - Pension Plan, Defined Benefit [Member]	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan, Actual Plan Asset Allocations	100.00%	100.00%
Equity Securities [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	49.00%	41.00%
Equity Securities [Member] \| Minimum [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	40.00%
Equity Securities [Member] \| Maximum [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	60.00%
Debt Securities [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	51.00%	59.00%
Debt Securities [Member] \| Minimum [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	40.00%
Debt Securities [Member] \| Maximum [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	60.00%

Pension and Postretirement Health and Life Benefits (Schedule of Fair Value of Plan Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Mortgage and asset backed securities	$ 0.3	$ 5.4
Pension Plan, Defined Benefit [Member]
US Government Securities	34.6	84.7
Corporate Debt	119.7	217.0
Municipal Bonds	3.5	6.2
Fair Value of Investments by Hierarchy Level	158.1	313.3
Investments measured at NAV	494.7	318.3
Accrued Interest Receivable	1.9	3.5
Unsettled Transactions Receivable	(0.1)	(1.0)
Defined Benefit Plan, Fair Value of Plan Assets	654.6	634.1	$ 656.3
Other Postretirement Benefit Plan, Defined Benefit [Member]
Money Market Funds	0.0	0.2
Bond Mutual Funds	1.8	7.5
Equity Mutual Funds	0.0	0.0
Fair Value of Investments by Hierarchy Level	1.8	7.7
Defined Benefit Plan, Fair Value of Plan Assets	1.8	7.7	$ 13.8
Fair Value, Inputs, Level 1 [Member] \| Other Postretirement Benefit Plan, Defined Benefit [Member]
Money Market Funds	0.0	0.2
Bond Mutual Funds	1.8	7.5
Equity Mutual Funds	0.0	0.0
Fair Value of Investments by Hierarchy Level	1.8	7.7
Fair Value, Inputs, Level 2 [Member] \| Other Postretirement Benefit Plan, Defined Benefit [Member]
US Government Securities	34.6	84.7
Corporate Debt	119.7	217.0
Mortgage and asset backed securities	0.3	5.4
Municipal Bonds	3.5	6.2
Fair Value of Investments by Hierarchy Level	$ 158.1	$ 313.3

Pension and Postretirement Health and Life Benefits (Schedule of Estimated Future Benefit Payments) (Details) $ in Millions	Dec. 31, 2017 USD ($)
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	$ 59.9
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	58.2
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	56.1
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	54.9
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	53.7
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	251.8
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	16.4
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	15.2
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	14.2
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	13.4
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	12.8
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	$ 53.1

Stock-Based Compensation (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Sep. 30, 2014
Common Stock, Shares Reserved for Future Issuance Under Management Incentive Plan	640,000	1,200,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 0.4
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	11 months
Restricted stock units potentially converted to common stock, shares	95,000
Employee Stock Option [Member]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 0.3
Restricted Stock Units (RSUs) [Member]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 0.0

Stock-Based Compensation (Stock-Based Compensation Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation [Abstract]
Restricted Stock or Unit Expense	$ 0.1	$ 0.2
Stock or Unit Option Plan Expense	0.4	0.3
Allocated Share-based Compensation Expense	$ 0.5	$ 0.5

Stock-Based Compensation (Assumptions Used in the Black-Scholes Option Pricing Model) (Details) - $ / shares $ / shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	0	15,000
Share-based Goods and Nonemployee Services Transaction, Valuation Method, Risk Free Interest Rate		1.91%
Share-based Goods and Nonemployee Services Transaction, Valuation Method, Expected Volatility Rate		75.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term, Simplified Method		6
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 0

Stock-Based Compensation (Options) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	0	15,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 0.00
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	(58,000)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price	$ 3.12
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	425,000	483,000
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 4.14	$ 4.02
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 0.1	$ 1.1
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	236,000
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 4.17
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	$ 0.1

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
Income Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2014	Dec. 31, 2015
Federal statutory income tax rate, percent										35.00%	35.00%
Federal net operating losses	$ 789.7									$ 789.7
Other tax attributes consisting primarily of tax basis in property	15.3									15.3
Cancellation of debt income for tax												$ 340.0
Annual limitation of NOL carryforwards and tax credits generated prior to ownership change										2.9
Deferred tax asset, increase (decrease)										(288.9)
Increase (decrease) in deferred tax asset valuation allowance										261.5	$ (24.4)
Cancellation of debt income for tax, adjustment										32.5	4.1
Provision (benefit) for income taxes	(0.1)		$ 0.0	$ 0.2	$ 0.0	$ 0.0	$ 0.0	$ 0.6		0.1	0.6
Other Comprehensive Income (Loss), Tax										0.0	0.0
Liability for Uncertain Tax Positions, Noncurrent	0.3				0.4					0.3	0.4		$ 1.0
Unrecognized Tax Benefits, Income Tax Penalties Expense Reduction										(0.1)	(0.4)
Income Tax Examination, Penalties and Interest Expense Reduction (Increase)										0.1	0.1
Income Tax Examination, Penalties and Interest Accrued					$ 0.1						$ 0.1
State and Local Jurisdiction [Member]
Federal net operating losses	$ 18.1									$ 18.1
Scenario, Forecast [Member]
Federal statutory income tax rate, percent									21.00%

Income Taxes Income Taxes (Taxes by Jurisdiction) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Current Income Tax Expense (Benefit)									$ (0.1)	$ (0.6)
Provision (benefit) for income taxes	$ 0.1		$ 0.0	$ (0.2)	$ 0.0	$ 0.0	$ 0.0	$ (0.6)	(0.1)	(0.6)
State and Local Jurisdiction [Member]
Current Income Tax Expense (Benefit)									$ (0.1)	$ (0.6)

Income Taxes Income Taxes (Deferred Income Taxes) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Components of Deferred Tax Assets and Liabilities [Abstract]
Deferred Tax Assets, Employee Benefits Costs	$ 79.9	$ 142.3
Deferred Tax Assets, Inventory	2.4	0.0
Deferred Tax Assets, Property, Plant and Equipment	187.0	318.8
Deferred Tax Assets, Net Operating Loss and Credit Carryforwards	166.9	254.9
Deferred Tax Assets, Accrued Expenses	0.9	7.9
Deferred Tax Assets, Long-Term Debt and Financing Costs	17.3	8.0
Deferred Tax Assets, Other	5.5	8.6
Deferred Tax Assets, Gross	459.9	740.5
Deferred Tax Assets, Valuation Allowance	(440.7)	(702.2)
Deferred Tax Assets, Net of Valuation Allowance	19.2	38.3
Deferred Tax Liabilities, Inventory	0.0	2.6
Deferred Tax Liabilities, Intangible Assets	17.7	33.0
Deferred Tax Liabilities, Prepaid Expenses	1.5	2.7
Deferred Tax Liabilities	$ 19.2	$ 38.3

Income Taxes Income Taxes (Rate Reconciliation) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
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, Gain on Early Extinguishment of Debt, Percent	268.00%	(6.00%)
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent	2382.00%
Effective Income Tax Rate Reconciliation, Interest Expense, Percent	4.00%	(3.00%)
Effective Income Tax Rate Reconciliation, Other Nondeductible Expense, Percent	1.00%
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent	(2156.00%)	(36.00%)
Effective Income Tax Rate Reconciliation, State Income Tax Expense, Percent	1.00%	(1.00%)
Effective Income Tax Rate Reconciliation, Percent	(1.00%)	1.00%

Income Taxes Income Taxes (Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Liability for Uncertain Tax Positions, Noncurrent	$ 0.3	$ 0.4	$ 1.0
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions	0.1
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	$ (0.2)	$ (0.6)

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, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Income Per Share Calculation [Line Items]
Net income (loss) allocable to common stockholders	$ 33.6	$ (10.5)	$ (24.4)	$ 6.6	$ (8.2)	$ (41.3)	$ (2.9)	$ (14.6)	$ 5.3	$ (67.0)
Weighted average number of shares outstanding, basic									9.1	9.1
Weighted average number of shares outstanding, diluted									9.1	9.1
Net income (loss) per share - basic and diluted					$ (0.90)	$ (4.54)	$ (0.32)	$ (1.60)	$ 0.58	$ (7.36)

Stockholders' Equity (Tables) (Details) - shares	12 Months Ended
Stockholders' Equity (Tables) (Details) - shares	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Common Stock, Shares, Issued	9,038,751
Preferred Stock, Shares Issued	104,574
Preferred Stock, Shares Outstanding	104,574
Common Class A [Member]
Class of Stock [Line Items]
Common Stock, Shares, Outstanding	7,632,669	7,563,600	7,563,600
Stock Issued During Period, Shares, New Issues	38,751
Conversion of Stock, Shares Converted	(30,318)
Common Stock, Shares, Issued	7,632,669	7,563,600
Common Class B [Member]
Class of Stock [Line Items]
Common Stock, Shares, Outstanding	1,406,082	1,436,400	1,436,400
Stock Issued During Period, Shares, New Issues	38,751
Conversion of Stock, Shares Converted	(30,318)
Common Stock, Shares, Issued	1,406,082	1,436,400

Stockholders' Equity (Narrative) (Details) - USD ($)	12 Months Ended
Stockholders' Equity (Narrative) (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2014
Class of Stock [Line Items]
Preferred Stock, Shares Authorized	20,000,000	20,000,000
Preferred Stock, Par Value Per Share	$ 1.00	$ 1.00
Common Stock, Shares, Issued	9,038,751
Common Stock, Shares Reserved for Future Issuance Under Management Incentive Plan	640,000		1,200,000
Preferred Stock, Shares Issued	104,574
Preferred Stock, Liquidation Preference Per Share	$ 1,000
Preferred stock	$ 4,600,000
Preferred Stock, Dividend Rate, Percentage	7.50%
Preferred stock dividend condition - minimum pension funding	90.00%
Preferred stock dividend condition - minimum net income preceding quarter	$ 7,500,000
Preferred stock dividend condition - minimum free cash flow preceding four quarters	35,000,000
Preferred stock dividend condition - minimum cash balance preceding quarter	150,000,000
Preferred Stock, Liquidation Preference, Value	111,500,000
Preferred Stock, Cumulative Undeclared Dividend	6,900,000
Operating Loss Carryforwards	$ 789,700,000
Common Stock Ownership Enabling Preferred Stock Purchase Rights	4.99%
Common Stock Ownership Enabling Preferred Stock Purchase Rights, Incremental	0.50%
Common Class A [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized	70,000,000	70,000,000
Common Stock, Par Value Per Share	$ 0.10	$ 0.10
Common Stock, Shares, Issued	7,632,669	7,563,600
Stock Issued During Period, Shares, New Issues	38,751
Conversion of Stock, Shares Converted	30,318
Common Class B [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized	30,000,000	30,000,000
Common Stock, Par Value Per Share	$ 0.10	$ 0.10
Common Stock, Shares, Issued	1,406,082	1,436,400
Stock Issued During Period, Shares, New Issues	38,751
Conversion of Stock, Shares Converted	30,318
Preferred Series B [Member]
Class of Stock [Line Items]
Preferred stock	$ 4,600,000	$ 0

Commitment and Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Decontamination and decommissioning obligations	$ 1.0
ARO financial assurance - current	16.1
Accrued lease turnover costs	0.8
ARO financial assurance - noncurrent	13.5
Termination benefit costs	3.5	$ 0.4
Operating Lease, Expense	$ 3.1	$ 2.9

Commitments and Contingencies (Minimum Operating Lease Payments) (Details) $ in Millions	Dec. 31, 2017 USD ($)
Operating Leased Assets [Line Items]
Operating leases, future minimum payments due, 2018	$ 3.7
Operating leases, future minimum payments due, 2019	1.7
Operating leases, future minimum payments due, 2020	0.9
Operating leases, future minimum payments due, 2021	0.9
Operating leases, future minimum payments due, 2022	0.9
Operating leases, future minimum payments due, thereafter	4.8
Operating leases, future minimum payments due	$ 12.9

Schedule of Revenue by Geographic Ares (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue United States									$ 134.5	$ 242.8
Revenue Japan									49.0	49.1
Revenue Belgium									34.9
Revenue Other Countries										19.4
Revenue Foreign									83.9	68.5
Revenues	$ 116.9	$ 50.3	$ 44.0	$ 7.2	$ 136.5	$ 21.4	$ 63.4	$ 90.0	$ 218.4	$ 311.3

Segment Information (Segment Reporting Information) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Revenues [Abstract]
Revenue, Contract Services									$ 23.0	$ 38.5
Total Revenue	$ 116.9	$ 50.3	$ 44.0	$ 7.2	$ 136.5	$ 21.4	$ 63.4	$ 90.0	218.4	311.3
Gross Profit	$ 52.0	$ 11.6	$ (4.3)	$ (2.5)	$ 25.9	$ (2.1)	$ 5.5	$ 15.8	56.8	45.1
Low Enriched Uranium Segment [Member]
Revenues [Abstract]
Revenue, Goods									195.4	272.8
Gross Profit									59.3	38.5
Contract Services Segment [Member]
Revenues [Abstract]
Gross Profit									(2.5)	6.6
Separative Work Units [Member]
Revenues [Abstract]
Revenue, Goods									195.4	258.5
Uranium [Member]
Revenues [Abstract]
Revenue, Goods									$ 0.0	$ 14.3

Segment Information (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting [Abstract]
Revenue from top 10 customers	97.00%	90.00%
Revenue from top 4 customers	53.00%	50.00%
Revenue from first customer over 10 percent	16.00%	15.00%
Revenue from second customer over 10 percent	14.00%	12.00%
Revenue from third customer over 10 percent	12.00%	12.00%
Revenue from fourth customer over 10 percent	11.00%	11.00%
Revenue from fifth customer over 10 percent	11.00%
Assets LEU segment	$ 657.4	$ 686.0
Assets contract services segment	17.9	27.5
Assets	$ 675.3	$ 713.5

Subsequent Event (Details) - USD ($) $ in Millions	3 Months Ended
Subsequent Event (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Subsequent Event [Line Items]
Accounts receivable, net		$ 60.2	$ 19.9
Customer Advances, Current		19.3
Government [Member]
Subsequent Event [Line Items]
Accounts receivable, net		14.5
Customer Advances, Current		$ 19.3
Scenario, Forecast [Member] \| Government [Member]
Subsequent Event [Line Items]
Litigation Settlement, Amount Awarded from Other Party	$ 24.0
Proceeds on claims	$ 4.7

Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Total Revenue	$ 116.9	$ 50.3	$ 44.0	$ 7.2	$ 136.5	$ 21.4	$ 63.4	$ 90.0	$ 218.4	$ 311.3
Cost of sales	64.9	38.7	48.3	9.7	110.6	23.5	57.9	74.2	161.6	266.2
Gross profit (loss)	52.0	11.6	(4.3)	(2.5)	25.9	(2.1)	5.5	15.8	56.8	45.1
Advanced technology costs	0.7	4.5	4.4	6.1	9.3	21.9	4.7	12.0	15.7	47.9
Selling, general and administrative	10.0	11.0	9.7	12.4	11.6	10.7	12.5	11.4	43.1	46.2
Amortization of intangible assets	4.9	2.5	2.0	1.2	4.9	1.7	2.7	3.2	10.6	12.5
Special charges for workforce reductions	2.4	2.4	2.3	2.4	0.2	0.6	0.6	0.0	9.5	1.4
Gains on sales of assets	(2.3)	(0.6)	(0.7)	(1.0)	(0.2)	(0.3)	(0.4)	(0.3)	(4.6)	(1.2)
Operating income (loss)	36.3	(8.2)	(22.0)	(23.6)	0.1	(36.7)	(14.6)	(10.5)	(17.5)	(61.7)
Gain on early extinguishment of debt and debt restructuring costs	0.0	0.0	0.0	(33.6)	3.7	0.0	(16.7)	0.0	(33.6)	(13.0)
Gain on early extinguishment of debt and debt restructuring costs				(33.6)					(33.6)	(16.7)
Interest expense	1.0	0.7	0.7	2.9	4.9	4.7	5.1	5.0	5.3	19.7
Investment income	(0.3)	(0.4)	(0.3)	(0.3)	(0.3)	(0.1)	(0.1)	(0.3)	(1.3)	(0.8)
Provision (benefit) for income taxes	0.1		0.0	(0.2)	0.0	0.0	0.0	(0.6)	(0.1)	(0.6)
Net income (loss)	35.5	(8.5)	(22.4)	7.6	(8.2)	(41.3)	(2.9)	(14.6)	12.2	(67.0)
Preferred stock dividends, undeclared and cumulative	1.9	2.0	2.0	1.0					6.9
Net income (loss) allocable to common stockholders	$ 33.6	$ (10.5)	$ (24.4)	$ 6.6	$ (8.2)	$ (41.3)	$ (2.9)	$ (14.6)	$ 5.3	$ (67.0)
Net income (loss) per share, basic	$ 3.69	$ (1.15)	$ (2.69)	$ 0.73					$ 0.58
Net income (loss) per share, diluted	$ 3.69	$ (1.15)	$ (2.69)	$ 0.72					0.58
Net income (loss) per share - basic and diluted					$ (0.90)	$ (4.54)	$ (0.32)	$ (1.60)	$ 0.58	$ (7.36)

Accumulated Other Comprehensive Income (Loss) (Notes)	12 Months Ended
Accumulated Other Comprehensive Income (Loss) (Notes)	Dec. 31, 2017
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. The amortization of prior service costs (credits) are 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.