Centrus Energy (LEU) 10-K22 Mar 212020 FY Annual reportFinancial data

Company Profile

Cover Page

Cover Page - USD ($) $ in Millions	12 Months Ended
Cover Page - USD ($) $ in Millions	Dec. 31, 2020	Mar. 01, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2020
Entity File Number	1-14287
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	52-2107911
Entity Address, Address Line One	6901 Rockledge Drive, Suite 800
Entity Address, City or Town	Bethesda
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	20817
City Area Code	(301)
Local Phone Number	564-3200
Title of 12(b) Security	Class A Common Stock, par value $0.10 per share
Trading Symbol	LEU
Security Exchange Name	NYSEAMER
Entity Interactive Data Current	Yes
Entity Registrant Name	CENTRUS ENERGY CORP
Entity Central Index Key	0001065059
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		12,660,676
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Public Float			$ 64.5
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Current Assets
Cash and cash equivalents	$ 152	$ 130.7
Accounts receivable, net	29.6	21.1
Inventories	64.8	64.5
Deferred costs associated with deferred revenue	151.9	144.1
Other current assets	7.8	9.2
Total current assets	406.1	369.6
Property, Plant and Equipment, Net	4.9	3.7
Deposits for surety bonds	5.7	5.7
Intangible assets	62.8	69.5
Other long-term assets	6.8	7.4
Total Assets	486.3	455.9
Current Liabilities
Accounts payable and accrued liabilities	50.6	50.7
Payables under SWU purchase agreements	21.3	8.1
Inventories owed to customers and suppliers	4.9	5.6
Deferred revenue and advances from customers	283.2	266.3
Current debt	6.1	6.1
Total current liabilities	366.1	336.8
Long-term debt	108	114.1
Postretirement health and life benefit obligations	130.8	138.6
Pension benefit liabilities	124.4	141.8
Advances from customers	45.2	29.4
Other long-term liabilities	32.4	32.1
Total liabilities	806.9	792.8
Commitments and contingencies (Note 11)
Stockholders' Deficit
Preferred stock	4.6
Excess of capital over par value	85	61.5
Accumulated deficit	(407.7)	(405)
Accumulated other comprehensive income (loss), net of tax	0.8	1.1
Total stockholders' deficit	(320.6)	(336.9)
Total Liabilities and Stockholders’ Equity (Deficit)	486.3	455.9
Preferred Series B [Member]
Stockholders' Deficit
Preferred stock	0.1	4.6
Common Class A [Member]
Stockholders' Deficit
Common stock	1.1	0.8
Common Class B [Member]
Stockholders' Deficit
Common stock	$ 0.1	$ 0.1

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	12 Months Ended
CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Preferred Stock, Par Value Per Share	$ 1	$ 1
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	$ 53,900,000	$ 127,200,000
Common Stock, Shares, Issued	12,109,389
Accumulated Depreciation, Property, Plant, and Equipment	$ 2,700,000	$ 2,200,000
Preferred Series B [Member]
Preferred Stock, Dividend Rate, Percentage	7.50%
Preferred Stock, Shares Issued	41,720	104,574
Preferred Stock, Liquidation Preference, Value	$ 53,900,000	$ 127,200,000
Common Class A [Member]
Common Stock, Par or Stated Value Per Share	$ 0.10	$ 0.10
Common Stock, Shares Authorized	70,000,000	70,000,000
Common Stock, Shares, Issued	11,390,189	8,347,427
Common Class B [Member]
Common Stock, Par or Stated Value Per Share	$ 0.10	$ 0.10
Common Stock, Shares Authorized	30,000,000	30,000,000
Common Stock, Shares, Issued	719,200	1,117,462

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Total revenue	$ 247.2	$ 209.7
Cost of sales	149.6	177.2
Gross profit (loss)	97.6	32.5
Advanced technology license and decommissioning costs	2.8	14.6
Selling, general and administrative	36	33.7
Amortization of intangible assets	6.8	6.5
Special charges for workforce reductions and advisory costs	0.6	(1.9)
Other (income)	0.4	(0.7)
Operating income (loss)	51	(19.7)
Nonoperating components of net periodic benefit expense (income)	(1.6)	(4.3)
Interest expense	0.1	3
Investment income	(0.5)	(2.2)
Income (loss) before income taxes	53	(16.2)
Provision (benefit) for income taxes	(1.4)	0.3
Net income (loss)	54.4	(16.5)
Preferred stock dividends, undeclared and cumulative	6.7	7.8
Distributed earnings allocable to retired preferred shares	41.9	0
Net income (loss) allocable to common stockholders	$ 5.8	$ (24.3)
Net income (loss) per common share - basic	$ 0.59	$ (2.54)
Net income (loss) per common share - diluted	$ 0.57	$ (2.54)
Weighted-average number of shares outstanding:
Average number of shares outstanding, basic	9,825	9,566
Average number of shares outstanding, diluted	10,123	9,566
Separative Work Units [Member]
Total revenue	$ 151.5	$ 123.7
Uranium [Member]
Total revenue	39	45.7
Product [Member]
Total revenue	190.5	169.4
Cost of sales	92.7	118.6
Service [Member]
Total revenue	56.7	40.3
Cost of sales	$ 56.9	$ 58.6

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash Flows from Operating Activities
Net income (loss)	$ 54.4	$ (16.5)
Adjustments to reconcile net income (loss) to net cash (used in) operating activities:
Depreciation and amortization	7.3	7
Accrued loss on long-term contract	(10.6)	18.3
Immediate recognition of retirement benefit plans (gains) losses, net	7.2	(4)
Interest on paid-in-kind toggle notes	0	1.1
Gain on sale of assets	0	(0.7)
Inventory valuation adjustments	0	2.3
Changes in operating assets and liabilities:
Accounts receivable – (increase) decrease	(8.6)	29.3
Inventories, net – (increase) decrease	25.8	0.1
Payables under SWU purchase agreements – increase (decrease)	13.2	(37.9)
Deferred revenue, net of deferred costs – increase (decrease)	9.7	44
Accounts payable and other liabilities – increase (decrease)	1.5	(12.3)
Pension and postretirement liabilities - increase (decrease)	(32.7)	(19.5)
Other, net	(0.1)	0.1
Net Cash (Used in) Operating Activities	67.1	11.3
Cash Flows Provided by Investing Activities
Capital expenditures	(1.4)	(0.1)
Proceeds from sales of assets	0	0.7
Net Cash Provided by (Used in) Investing Activities	(1.4)	0.6
Cash Flows Used in Financing Activities
Proceeds from Issuance of Common Stock	23.1	0
Payments for Repurchase of Preferred Stock and Preference Stock	(61.6)	0
Payment of interest classified as debt	(6.1)	(6.1)
Proceeds from Stock Options Exercised	0.3	0
Payment of Financing and Stock Issuance Costs	(0.1)	(1.4)
Principal payments on debt	0	(27.5)
Net cash used in financing activities	(44.4)	(35)
Decrease in cash, cash equivalents and restricted cash	21.3	(23.1)
Cash, cash equivalents and restricted cash, start of period	136.6	159.7
Cash, cash equivalents and restricted cash, end of period	157.9	136.6
Supplemental Cash Flow Information:
Interest paid	0	1.5
Conversion of interest payable-in-kind to long-term debt	0	0.7
Property, plant and equipment included in accounts payable and accrued liabilities
Supplemental Cash Flow Information:
Other Significant Noncash Transaction, Value of Consideration Given	(0.3)	0
Deferred financing costs included in accounts payable and accrued liabilities [Member]
Supplemental Cash Flow Information:
Other Significant Noncash Transaction, Value of Consideration Given	(0.2)	(0.8)
Disposal of right to use lease assets for early termination [Member]
Supplemental Cash Flow Information:
Other Significant Noncash Transaction, Value of Consideration Given	(0.2)	(0.4)
Right to use lease assets acquired under operating leases [Member]
Supplemental Cash Flow Information:
Other Significant Noncash Transaction, Value of Consideration Received	0	$ 5.2
Preferred Series B [Member]
Cash Flows Used in Financing Activities
Payments for Repurchase of Preferred Stock and Preference Stock	$ (60)

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' DEFICIT - USD ($) $ in Millions	Total	Preferred Stock [Member]	Common Stock [Member]	Common Stock [Member]Common Class A [Member]	Common Stock [Member]Common Class B [Member]	Excess of Capital over Par Value [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance at Dec. 31, 2018	$ (321.9)	$ 4.6		$ 0.8	$ 0.1	$ 61.2	$ (388.5)	$ (0.1)
Net income (loss)	(16.5)						(16.5)
Other comprehensive income, net of tax	1.2							1.2
Restricted and other common stock issued, net of amortization	0.3					0.3
Ending Balance at Dec. 31, 2019	(336.9)	4.6		0.8	0.1	61.5	(405)	1.1
Net income (loss)	54.4						54.4
Stock issued during period	23.1		$ 0.3			22.8
Stock Repurchased and Retired During Period, Value	(61.6)	(4.5)					(57.1)
Other comprehensive income, net of tax	(0.3)							(0.3)
Restricted and other common stock issued, net of amortization	0.7					0.7
Ending Balance at Dec. 31, 2020	$ (320.6)	$ 0.1		$ 1.1	$ 0.1	$ 85	$ (407.7)	$ 0.8

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
Summary of Significant Accounting Policies	Dec. 31, 2020
Summary of Significant Accounting Policies [Abstract]
Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation and Principles of Consolidation The consolidated financial statements of Centrus Energy Corp. (“Centrus” or the “Company”), which include the accounts of the Company, its principal subsidiary United States Enrichment Corporation (“Enrichment Corp.”) and its other subsidiaries, were prepared in conformity with generally accepted accounting principles in the U.S. (“U.S. GAAP”). Certain prior year amounts have been reclassified for consistency with the current year presentation. All material intercompany transactions have been 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, revenue and related costs, asset valuations, 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 U 235 and depleted uranium having a lower percentage of U 235 . The SWU contained in LEU is calculated using an industry standard formula based on the physics of enrichment. The amount of enrichment deemed to be contained in LEU under this formula is commonly referred to as its SWU component and the quantity of natural uranium deemed to be used in the production of LEU under this formula is referred to as its uranium or “feed” component. SWU and uranium inventory costs are determined using the 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 Company evaluates the carrying values of property, plant and equipment and identifiable intangible assets when events or changes in business circumstances indicate that the carrying amount of asset, or asset group, may not be fully recoverable. The carrying amount of a long-lived asset is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset. An impairment loss is measured as the amount by which the carrying amount of a long-lived asset, or asset group exceeds its fair value. 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’ 8.25% notes (the “8.25% Notes”) are recorded at face value and the fair value is disclosed. The estimated fair value of the 8.25% Notes is based on recent trading prices and bid/ask quotes as of or near the balance sheet date. Debt issuance costs are deferred and amortized over the life of the instrument. The balance sheet carrying amounts for accounts receivable, accounts payable and accrued liabilities, and payables under SWU purchase agreements approximate fair value because of the short-term nature of the instruments. Concentrations of Credit Risk Credit risk could result from the possibility of a customer failing to perform or pay according to the terms of a contract. Extension of credit is based on an evaluation of each customer’s financial condition. Centrus regularly monitors credit risk exposure and takes steps intended to mitigate the likelihood of such exposure resulting in a loss. Segments Centrus operates two business segments: LEU, which supplies various components of nuclear fuel to utilities, and technical solutions, which provides advanced engineering, design, and manufacturing services to government and private sector customers. Revenue The Company accounts for a contract when it has approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and collectability of consideration is probable. Revenue for product and service sales is recognized when or as the Company transfers control of the promised products or services to the customer. Revenue is measured at the transaction price, which is based on the amount of consideration that the Company expects to receive in exchange for transferring the promised goods or services to the customer. The transaction price will include estimates of variable consideration until it is probable that a significant reversal of revenue recognized will not occur. SWU and Uranium Revenue Revenue for the Company’s LEU segment 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. Contracts with customers are primarily long-term, fixed-commitment contracts under which its customers are obligated to purchase a specified quantity of the SWU component of LEU or the SWU and uranium components of LEU. The Company’s contracts for natural uranium are generally shorter-term, fixed-commitment contracts. Revenue is recognized at the time the customer obtains control of the LEU or uranium. Customers generally obtain control of LEU at nuclear 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. Each such delivery to a customer is accounted for as a distinct performance obligation under a contract, and a contract may call for multiple deliveries over a number of periods. The contract’s transaction price is allocated to each performance obligation based on the observable standalone selling price of each distinct delivery of SWU or uranium. Utility customers in general have the option to defer receipt of uranium products purchased from the Company beyond the contractual sale period. In such cases, title to SWU and/or uranium components are transferred to the customer and a performance obligation for Centrus is created and a receivable is recorded. Cash is collected for the receivable under normal credit terms. The performance obligation is represented as Deferred Revenue on the consolidated balance sheet and the customer-titled product is classified as Deferred Costs Associated with Deferred Revenue on the consolidated balance sheet. Risk of loss remains with Centrus until the customer obtains control of the uranium product. The recognition of revenue and related cost of sales occurs at the point in time at which the customer obtains control of SWU or uranium and risk of loss of the product transfers to the customer, which may occur beyond one year. The timing of the transfer of control, 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, the Company will accept payment in the form of uranium. Revenue from the sale of SWU under such contracts is recognized at the time transfer of control of LEU occurs and is based on the fair value of the uranium at contract inception or as the quantity of uranium is finalized, if variable. The Company may also borrow SWU from customers, in which case the Company will record the SWU and the related liability for the borrowing using a projected average purchase price over the borrowing period. Amounts billed to customers for handling costs are included in sales. Handling costs are accounted for as a fulfillment cost and are included in cost of sales. The Company does not have shipping costs associated with outbound freight after control over a product has transferred to a customer. The Company’s contracts with customers do not provide for significant payment terms or financing components. Technical Solutions Revenue Revenue for the technical solutions segment, principally representing technical, manufacturing, engineering, procurement, construction and operations services offered to public and private sector customers, is recognized over the contractual period as services are rendered. The Company recognizes revenue over time as it performs on these contracts because of the continuous transfer of control to the customer. For public sector contracts, this continuous transfer of control to the customer is supported by clauses in the contract that allow the customer to unilaterally terminate the contract for convenience, pay the Company for costs incurred plus a reasonable profit and assume control of any work in progress. The Company’s private sector contracts generally contain contractual termination clauses or entitle the Company to payments for work performed to date for goods and services that do not have an alternative use. With control transferring over time, revenue is recognized based on the extent of progress towards completion of the performance obligation. A contract may contain one or more performance obligations. Two or more promises to transfer goods or services to a customer may be considered a single performance obligation if the goods or services are highly interdependent or highly interrelated such that utility of the promised goods or services to the customer includes integration services provided by the Company. The Company determines the transaction price for each contract based on the consideration it expects to receive for the products or services being provided under the contract. If transaction prices are not stated in the contract for each performance obligation, contractual prices are allocated to performance obligations based on estimated relative standalone selling prices of the promised services. The Company generally uses the cost-to-cost input method of progress for performance obligations to deliver products with continual transfer of control to the customer, because it best depicts the transfer of control to the customer that occurs as the Company incurs costs. Under the cost-to-cost method, the extent of progress towards completion is measured based on the proportion of direct costs incurred to date to the total estimated direct costs at completion of the performance obligation. Revenues are recorded proportionally as costs are incurred. For performance obligations to provide services to the customer, revenue is recognized over time based on direct costs incurred or the right to invoice method (in situations where the value transferred matches the Company’s billing rights) as the customer receives and consumes the benefits. Use of the cost-to-cost method requires the Company to make reasonably dependable estimates of costs at completion associated with the design, manufacture and delivery of products and services in order to calculate revenue. Significant judgment is used to estimate total revenue and costs at completion, particularly in the assumptions related to internal labor hours and third-party services for which a vendor invoice or quote is not yet available. As a significant change in one or more estimates could affect the profitability of the Company’s contracts, the Company reviews and updates its contract-related estimates regularly. Adjustments in estimated profits/losses are recognized under the cumulative catch-up method. Under this method, the impact of the adjustments is recognized in the period the adjustment is recognized. When estimates of total costs at completion for such an integrated, construction type contract exceed total estimates of revenue to be earned on a performance obligation related to complex equipment or related services, a provision for the remaining loss on the performance obligation is recognized in the period the loss is determined. The Company has applied the practical expedient in paragraph ASC 606-10-50-14 and does not disclose the value of remaining performance obligations under service contracts having original expected terms of one year or less. The timing of revenue recognition may differ from the timing of invoicing to customers. Progress on satisfying performance obligations under contracts with customers and the related billings and cash collections are recorded on the consolidated balance sheet as contract assets or contract liabilities. Contract balances are classified as assets or liabilities on a contract-by-contract basis at the end of each reporting period. Unbilled receivables are included in Accounts Receivable on the consolidated balance sheet and arise when the timing of cash collected from customers differs from the timing of revenue recognition, such as when contract provisions require specific milestones to be met before a customer can be billed. Those assets are recognized when the revenue associated with the contract is recognized prior to billing and derecognized when billed in accordance with the terms of the contract. To the extent billings to the customer precede the recognition of technical solutions revenue, the Company recognizes a liability included in Deferred Revenue and Advances from Customers on the consolidated balance sheet. Advanced Technology Costs American Centrifuge and related expenses that are outside of our customer contracts are included in Advanced Technology Costs . 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, notional stock units, stock appreciation rights, restricted stock units, restricted stock, performance awards, dividend equivalent rights and other stock based awards. Stock-based compensation cost for options and stock-settled awards are 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. Stock-based compensation cost for awards likely to be settled with cash payments are recognized over the requisite service period and accrued as a liability and re-measured each reporting period based on the trading price of the Company’s common stock. New Accounting Standards Recently Adopted Accounting Standards In June 2016, the Financial Accounting Standard Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, Measurement of Credit Losses on Financial Instruments , which requires estimating all expected credit losses for certain types of financial instruments, including trade receivables, held at the reporting date based on historical experience, current conditions and reasonable and supportable forecasts. ASU 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The Company adopted this standard in the first quarter of fiscal 2020 and there was no material impact. Accounting Standards Effective in Future Periods In August 2018, the FASB issued ASU 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20),

Revenue and Contracts with Cust

Revenue and Contracts with Customers	12 Months Ended
Revenue and Contracts with Customers	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer	REVENUE AND CONTRACTS WITH CUSTOMERS Disaggregation of Revenue The following table presents revenue from SWU and uranium sales disaggregated by geographical region, including foreign countries representing 10% or more of revenue, based on the billing addresses of customers (in millions): Year Ended December 31, 2020 2019 United States $ 115.0 $ 112.1 Foreign: Belgium 35.8 21.5 Japan 23.4 23.4 Other 16.3 12.4 Total foreign 75.5 57.3 Revenue - SWU and uranium $ 190.5 $ 169.4 Refer to Note 19, Revenue by Geographic Area, Major Customers and Segment Information for disaggregation of revenue by segment. Disaggregation by end-market is provided in Note 19 and the consolidated statements of operations. SWU sales are made primarily to electric utility customers and uranium sales are primarily made to other nuclear fuel related companies. Technical solutions revenue resulted primarily from services provided to the government and its contractors. SWU and uranium revenue is recognized at point of sale and technical solutions revenue is generally recognized over time. SWU revenue in 2020 includes $32.6 million collected from a customer in settlement of a supply contract that was subject to the customer’s bankruptcy proceeding. Refer to Note 17, Commitments and Contingencies - Legal Matters, for details. Accounts Receivable December 31, 2020 2019 ($ millions) Accounts receivable: Billed $ 23.0 $ 13.2 Unbilled * 6.6 7.9 Accounts receivable $ 29.6 $ 21.1 * Billings under certain contracts in the technical services segment are invoiced based on approved provisional billing rates. Unbilled revenue represents difference between actual costs incurred and invoiced amounts. The Company expects to invoice and collect the unbilled amounts after actual rates are submitted to the customer and approved. Unbilled revenue also includes unconditional rights to payment that are not yet billable under applicable contracts pending the compilation of supporting documentation. Contract Liabilities The following table presents changes in contract liability balances (in millions): December 31, 2020 2019 Change Accrued loss on HALEU Contract: Current - Accounts payable and accrued liabilities $ 7.0 $ 10.0 $ (3.0) Noncurrent - Other long-term liabilities $ 0.7 $ 8.3 $ (7.6) Deferred revenue - current $ 281.7 $ 243.0 $ 38.7 Advances from customers - current $ 1.5 $ 23.3 $ (21.8) Advances from customers - noncurrent $ 45.2 $ 29.4 $ 15.8 Deferred sales totaled $38.7 million and $49.2 million in the years ended December 31, 2020, and 2019, respectively. Previously deferred sales recognized in revenue totaled $0 and $10.7 million in the years ended December 31, 2020, and 2019, respectively. LEU Segment The SWU component of LEU is typically bought and sold under contracts with deliveries over several years. The Company’s agreements for natural uranium sales are generally shorter-term, fixed-commitment contracts. The Company’s order book of sales under contract in the LEU segment (“order book”) extends to 2030. As of December 31, 2020, the order book was approximately $960 million. The order book represents the estimated aggregate dollar amount of revenue for future SWU and uranium deliveries under contract and includes approximately $328 million of Deferred Revenue and Advances from Customers. Refer to Contract Liabilities table above. As of December 31, 2019, the order book was approximately $1.0 billion. Most of the Company’s enrichment contracts provide for fixed purchases of SWU during a given year. T he Company’s order book is partially based on customers’ estimates of the timing and size of their fuel requirements and other assumptions that are subject to change. For example, depending on the terms of specific contracts, the customer may be able to increase or decrease the quantity delivered within an agreed range. T he Company’s order book estimate is also based on the Company’s estimates of selling prices, which may be subject to change. For example, depending on the terms of specific contracts, prices may be adjusted based on escalation using a general inflation index, published SWU price indicators prevailing at the time of delivery, and other factors, all of which are variable. T he Company uses external composite forecasts of future market prices and inflation rates in its pricing estimates. Under the terms of certain contracts with customers in the LEU segment, the Company will accept payment for SWU 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 at contract inception, or as the quantity of uranium is finalized, if variable. In both 2019 and 2020, SWU revenue of $23.4 million was recognized under such contracts based on the fair market value of uranium acquired in exchange for SWU delivered. Uranium received from customers as advance payments for the future sales of SWU totaled $44.4 million as of December 31, 2020. The advance payments are included in either Advances from Customers, Current or Advances from Customers, Noncurrent, based on the anticipated SWU sales period. In 2020, the Company borrowed SWU inventory valued at $11.2 million from a customer and recorded the SWU and the related liability using an average purchase price over the borrowing period. The cumulative liability to the customer of $20.7 million for borrowed inventory is included in Other Long-Term Liabilities . Technical Solutions Segment Revenue for the technical solutions segment, representing the Company’s technical, manufacturing, engineering, procurement, construction and operations services offered to public and private sector customers, is recognized over the contractual period as services are rendered. For details, refer to Note 1, Summary of Significant Accounting Policies — Revenue — Technical Solutions Revenue. On October 31, 2019, the Company signed a three-year cost-share contract with the U.S. Department of Energy (“DOE”) (“the HALEU Contract”) to deploy a cascade of centrifuges to demonstrate production of high-assay, low-enriched uranium (“HALEU”) for advanced reactors. HALEU is a component of an advanced nuclear reactor fuel that is not commercially available today and may be required for a number of advanced reactor designs currently under development in both the commercial and government sectors. The program has been under way since May 31, 2019, when the Company and DOE signed a preliminary letter agreement that allowed work to begin while the full contract was being finalized. Under the HALEU Contract, DOE agreed to reimburse the Company for 80% of its costs incurred in performing the contract, up to a maximum of $115 million. The Company’s cost share is the corresponding 20% and any costs incurred above these amounts. Costs under the HALEU Contract include program costs , including internal labor, third-party services and materials and associated indirect costs that are classified as Cost of Sales , and an allocation of corporate costs supporting the program that are classified as Selling, General and Administrative Expenses . Services to be provided over the three-year contract include constructing and assembling centrifuge machines and related infrastructure in a cascade formation. When estimates of total costs at completion for such an integrated, construction-type contract exceed estimates of total revenue to be earned, a provision for the remaining loss on the contract is recorded to Cost of Sales in the period the loss is determined. The Company’s corporate costs supporting the program are recognized as expense as incurred over the duration of the contract term. As of December 31, 2019, the portion of the Company’s anticipated cost share under the HALEU Contract representing the Company’s share of remaining projected program costs was recognized in Cost of Sales as an accrued loss of $18.3 million, The accrued loss on the contract is being adjusted over the remaining contract term based on actual results and remaining program cost projections. As of December 31, 2020, the accrued contract loss balance was $7.7 million, consisting of $7.0 million included in Accounts Payable and Accrued Liabilities and $0.7 million included in Other Long-Term Liabilities . Cost of sales in the year ended December 31, 2020 benefited by $10.6 million for previously accrued contract losses attributable to work performed in 2020. The HALEU Contract is incrementally funded and DOE is currently obligated for costs up to approximately $87.4 million of the $115 million. The Company received cash payments of $55.8 million through December 31, 2020. Of the $115 million of anticipated revenue over the three-year contract term, approximately $4.9 million is anticipated to be recognized as revenue in 2022 (beyond twelve months from the fiscal year ended December 31, 2020).

Special Charges

Special Charges	12 Months Ended
Special Charges	Dec. 31, 2020
Restructuring and Related Activities [Abstract]
Special Charges	SPECIAL CHARGES Special charges for workforce reductions totaled $0.6 million in 2020. Special charges (credits) in 2019 included income of $2.9 million for the reversal of accrued termination benefits for employees who were retained for the HALEU program. A summary of termination benefit activity an d the accrued liability follows (in millions): Liability Year Ended Liability Charges (Credits) for Termination Benefits Paid Workforce reductions: Corporate functions $ 1.2 $ 0.6 $ (1.8) $ — Piketon facility 0.2 — (0.2) — Total $ 1.4 $ 0.6 $ (2.0) $ —

Cash, Cash Equivalents and Rest

Cash, Cash Equivalents and Restricted Cash	12 Months Ended
Cash, Cash Equivalents and Restricted Cash	Dec. 31, 2020
Cash, Cash Equivalents and Restricted Cash [Abstract]
Cash and Cash Equivalents Disclosure	CASH, CASH EQUIVALENTS AND RESTRICTED CASH The following table summarizes the Company’s cash, cash equivalents and restricted cash as presented on the consolidated balance sheet to amounts on the consolidated statement of cash flows (in millions): December 31, 2020 2019 Cash and cash equivalents $ 152.0 $ 130.7 Deposits for financial assurance - current 0.2 0.2 Deposits for financial assurance - noncurrent 5.7 5.7 Total cash, cash equivalents and restricted cash $ 157.9 $ 136.6 The following table provides additional detail regarding the Company’s deposits for financial assurance (in millions): December 31, 2020 December 31, 2019 Current Long-Term Current Long-Term Workers compensation — 5.4 — 5.4 Other 0.2 0.3 0.2 0.3 Total deposits for financial assurance $ 0.2 $ 5.7 $ 0.2 $ 5.7

Inventories

Inventories	12 Months Ended
Inventories	Dec. 31, 2020
Inventory, Net [Abstract]
Inventories	INVENTORIES Centrus holds uranium at licensed locations in the form of natural uranium and as the uranium component of LEU. Centrus also holds SWU as the SWU component of LEU at licensed locations (e.g., fabricators) to meet book transfer requests by customers. Fabricators process LEU into fuel for use in nuclear reactors. Components of inventories are as follows (in millions): December 31, 2020 December 31, 2019 Current Current Inventories, Net Current Current Inventories, Net Separative work units $ 17.0 $ 4.6 $ 12.4 $ 7.8 $ — $ 7.8 Uranium 47.8 0.3 47.5 56.7 5.6 51.1 Total $ 64.8 $ 4.9 $ 59.9 $ 64.5 $ 5.6 $ 58.9 (a) Inventories owed to customers and suppliers, included in current liabilities, include SWU and uranium inventories owed to fabricators. Inventories are valued at the lower of cost or net realizable value. Valuation adjustments for uranium inventory to reflect declines in uranium market price indicators totaled $2.3 million in 2019. There were no valuation adjustments in 2020. In March 2019, the Company completed a purchase of SWU and uranium from Nuclear Fuel Industries, Ltd. (“NFI”) for $7.1 million pursuant to an August 2018 agreement between Enrichment Corp. and NFI. Toshiba America Nuclear Energy Corporation (“TANE”) holds 718,200 shares of the Company’s Class B common stock and certain of the 8.25% Notes. Each of NFI and TANE are wholly-owned, indirect subsidiaries of Toshiba Corporation.

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
Property, Plant and Equipment	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENT A summary of changes in property, plant and equipment follows (in millions): December 31, Additions / (Depreciation) December 31, Land $ 1.2 $ — $ 1.2 Buildings and leasehold improvements 2.5 1.4 3.9 Machinery and equipment 1.1 0.3 1.4 Other 1.1 — 1.1 Property, plant and equipment, gross 5.9 1.7 7.6 Accumulated depreciation (2.2) (0.5) (2.7) Property, plant and equipment, net $ 3.7 $ 1.2 $ 4.9 Depreciation expense was $0.5 million in 2020 and $0.6 million in 2019. The Company did not sell any property in 2020. The Company sold fully-depreciated property for $0.7 million in 2019. Cash proceeds received totaled $0.7 million in 2019.

Intangible Assets

Intangible Assets	12 Months Ended
Intangible Assets	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	INTANGIBLE ASSETS Intangible assets originated from the Company’s reorganization and application of fresh start accounting as of September 30, 2014, the date the Company emerged from bankruptcy, 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 statements of operations. Intangible asset balances are as follows (in millions): December 31, 2020 December 31, 2019 Gross Carrying Amount Accumulated Amortization Net Amount Gross Carrying Amount Accumulated Amortization Net Amount Sales order book $ 54.6 $ 32.0 $ 22.6 $ 54.6 $ 29.9 $ 24.7 Customer relationships 68.9 28.7 40.2 68.9 24.1 44.8 Total $ 123.5 $ 60.7 $ 62.8 $ 123.5 $ 54.0 $ 69.5 The amount of amortization expense for intangible assets in each of the succeeding years is estimated to be as follows (in millions): 2021 $ 8.0 2022 9.6 2023 7.5 2024 9.4 2025 5.8 Thereafter 22.5 Total $ 62.8

Accounts Payable and Accrued Li

Accounts Payable and Accrued Liabilities	12 Months Ended
Accounts Payable and Accrued Liabilities	Dec. 31, 2020
Accounts Payable and Accrued Liabilities [Abstract]
Accounts Payable and Accrued Liabilities [Text Block]	ACCOUNTS PAYABLE AND ACCRUED LIABILITIES Components of accounts payable and accrued liabilities follow (in millions): December 31, 2020 2019 Trade payables $ 4.9 $ 7.0 Compensation and employee benefits 22.2 13.1 Postretirement health and life benefit obligations - current 11.6 14.2 Accrued HALEU Contract loss - current 7.0 10.0 Operating lease liability 2.4 2.5 Severance — 1.4 Other accrued liabilities 2.5 2.5 Total accounts payable and accrued liabilities $ 50.6 $ 50.7

Debt

Debt	12 Months Ended
Debt	Dec. 31, 2020
Debt Disclosure [Abstract]
Debt	DEBT A summary of debt follows (in millions): December 31, 2020 December 31, 2019 Maturity Current Long-Term Current Long-Term 8.25% Notes: Feb. 2027 Principal $ — $ 74.3 $ — $ 74.3 Interest 6.1 33.7 6.1 39.8 Total $ 6.1 $ 108.0 $ 6.1 $ 114.1 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 shown in the table 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, 2020, and December 31, 2019, $6.1 million of interest is recorded as current and classified as Current Debt in the consolidated balance sheet. The 8.25% Notes rank equally in right of payment with all of the Company’s existing and future unsubordinated indebtedness other than its 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 the Company’s 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 indenture governing the 8.25% Notes (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 indenture governing the 8.25% Notes (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 lien securing the Enrichment Corp. guarantee of the 8.25% Notes is 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.

Leases

Leases	12 Months Ended
Leases	Dec. 31, 2020
Leases [Abstract]
Lessee, Operating Leases [Text Block]	LEASES Centrus leases facilities and equipment under operating leases. Lease expense for operating leases is recognized on a straight-line basis over the lease term. The Company has facility leases with terms greater than 12 months, and the Company records the related asset and obligation at the present value of lease payments over the term. Leases with an initial term of 12 months or less are not recorded on the balance sheet. Refer to Note 1, Summary of Significant Accounting Policies , for information regarding the Company’s adoption of Topic 842 on January 1, 2019. Lease assets represent the right to use an underlying asset for the lease term, and lease liabilities represent the obligation to make lease payments arising from the lease. Lease assets exclude lease incentives. Lease terms reflect options to extend or terminate the lease when it is reasonably certain that those options will be exercised. The depreciable life of lease assets and leasehold improvements is limited by the expected lease term. The weighted-average remaining lease term was 3.2 years at December 31, 2020, with maturity dates ranging from July 2021 to September 2027, and the weighted-average discount rate was 12.2%. Lease expense amounted to $2.6 million and $2.7 million for the years ended December 31, 2020 and 2019, respectively. Lease expense primarily related to operating leases and for the years ended December 31, 2020 and 2019 includes a $0.3 million and $0.5 million credit, respectively, from DOE for true-up of prior years’ lease expense. Other amounts related to short-term lease expense were insignificant. Operating lease expense is included in Cost of Sales, Selling, General and Administrative Expenses and Advance Technology Costs on the Statement of Operations. Cash paid for amounts included in operating cash flows for operating leases was $3.2 million for the year ended December 31, 2020. The Company leases facilities and related personal property in Piketon, Ohio from DOE. On May 31, 2019, in connection with the HALEU letter agreement, DOE and the Company amended the lease agreement, which was scheduled to expire by its terms on June 30, 2019. The lease was renewed and extended until May 31, 2022, provided, however, that the lease may be terminated early upon completion of the work under the HALEU Contract. Any facilities, centrifuges or other equipment constructed or installed under contract with DOE will be owned by DOE and may be returned to DOE in an “as is” condition at the end of the lease term, and DOE would be responsible for its D&D. The Company accounted for the amendment as a modification and reassessed its classification. The Company classified the lease as an operating lease as the lease does not contain a transfer of ownership or purchase option, the fair value of the underlying asset cannot be practicably determined, and the economic life of the asset is indeterminate. The remeasurement of the remaining future lease payments through May 31, 2022 resulted in the recording of $3.8 million of additional lease assets and liabilities related to the modification. The modification resulted in an insignificant impact on the consolidated statement of operations. On October 8, 2019 the DOE notified the Company of an increase in the monthly lease payment beginning with the October 2019 payment. The Company accounted for the amendment as a modification and reassessed its classification. The remeasurement of the remaining future lease payments through May 31, 2022 resulted in the recording of $1.4 million additional lease assets and liabilities related to the modification. Centrus had a lease with DOE for centrifuge testing facilities in Oak Ridge, Tennessee through December 2019. In connection with the completion of work performed for D&D of the facility, the Company terminated the lease on September 30, 2019. The Company derecognized the remaining lease asset and related liability of $0.2 million. There was no gain or loss associated with the termination of the lease. Operating Lease Assets and Liabilities The table below presents the lease-related assets and liabilities recorded on the balance sheet (in millions). December 31, 2020 Classification on the Balance Sheet Lease assets $ 4.6 Other long-term assets Lease liabilities: Current 2.4 Accounts payable and accrued liabilities Noncurrent 4.3 Other long-term liabilities Total lease liabilities $ 6.7 Maturity of Operating Lease Liabilities The table below reconciles undiscounted payments for operating leases with terms greater than 12 months to the operating lease liabilities recorded on the balance sheet (in millions). 2021 $ 3.2 2022 1.8 2023 1.0 2024 1.0 2025 1.0 Thereafter 1.8 Total lease payments 9.8 Less imputed interest 3.1 Present value of lease payments $ 6.7

Fair Value Measurements

Fair Value Measurements	12 Months Ended
Fair Value Measurements	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE 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, 2020 December 31, 2019 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets: Cash and cash equivalents $ 152.0 $ — $ — $ 152.0 $ 130.7 $ — $ — $ 130.7 Deferred compensation asset (a) 2.4 — — 2.4 1.8 — — 1.8 Liabilities: Deferred compensation obligation (a) $ 2.3 $ — $ — $ 2.3 $ 1.8 $ — $ — $ 1.8 (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 Level 1, 2 or 3 during the periods presented. Other Financial Instruments As of December 31, 2020 and 2019, 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 their short-term nature. The carrying value and estimated fair value of long-term debt are as follows (in millions): December 31, 2020 December 31, 2019 Carrying Value Estimated Fair Value (a) Carrying Value Estimated Fair Value (a) 8.25% Notes $ 114.1 (b) $ 68.6 $ 120.2 (b) $ 61.5 (a) Based on recent trading prices and bid/ask quotes as of or near the balance sheet date, which are considered Level 2 inputs based on the frequency of trading. (b) The carrying value of the 8.25% Notes consists of the principal balance of $74.3 million and the sum of current and noncurrent interest payment obligations until maturity. Refer to Note 9, Debt

Pension and Postretirement Heal

Pension and Postretirement Health and Life Benefits	12 Months Ended
Pension and Postretirement Health and Life Benefits	Dec. 31, 2020
Retirement Benefits, Description [Abstract]
Pension and Postretirement Health and Life Benefits	PENSION AND POSTRETIREMENT HEALTH AND LIFE BENEFITS There are approximately 4,600 employees and retirees covered by qualified defined benefit pension plans providing retirement benefits based on compensation and years of service, and approximately 2,600 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 ($ millions) Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 Changes in Benefit Obligations: Obligations at beginning of period $ 763.5 $ 733.8 $ 152.8 $ 151.6 Actuarial (gains) losses, net 56.7 59.8 (1.6) 9.1 Service costs 3.5 3.3 — — Interest costs 24.3 30.3 4.8 6.0 Benefits paid from Plan assets (56.3) (59.1) (13.6) (13.9) Benefits paid from Company assets (0.5) — — — Plan amendments — (1.3) — — Settlements (30.4) — — — Administrative expenses paid (2.9) (3.3) — — Obligations at end of period 757.9 763.5 142.4 152.8 Changes in Plan Assets: Fair value of plan assets at beginning of period 621.2 563.5 — — Actual return on plan assets 85.4 109.3 — — Company contributions 16.6 10.8 13.6 13.9 Benefits paid (56.8) (59.1) (13.6) (13.9) Settlements (30.4) — — — Administrative expenses paid (2.9) (3.3) — — Fair value of plan assets at end of period 633.1 621.2 — — Unfunded status at end of period $ (124.8) $ (142.3) $ (142.4) $ (152.8) Amounts recognized in assets and liabilities: Current liabilities $ (0.4) $ (0.5) (11.6) (14.2) Noncurrent liabilities (124.4) (141.8) (130.8) (138.6) $ (124.8) $ (142.3) $ (142.4) $ (152.8) Amounts in accumulated other comprehensive income (loss), pre-tax: Prior service cost (credit) $ (1.1) $ (1.3) $ (2.1) $ (2.3) Discount rate used to determine benefit obligations at end of period: 2.5 % 3.3 % 2.5 % 3.3 % 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 2020 and 2019. 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. In March 2019, the lump sum payment option was made permanent 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. As part of the Company’s continued effort to reduce the size and volatility of its pension obligations and administrative costs, the Company transferred approximately $30.4 million of pension plan assets and approximately $30.4 million of related benefit obligations to an insurance company through the purchase of a group annuity contract in the fourth quarter of 2020. 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 $757.9 million and $763.5 million as of December 31, 2020 and 2019, respectively. As of December 31, 2020 and 2019, 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) The Company reports service costs for its defined benefit pension plans and its postretirement health and life benefit plans in Cost of Sales and Selling, General and Administrative Expenses . The remaining components of net periodic benefit credits (costs) are reported as Nonoperating Components of Net Periodic Benefit Expense (Income). Defined Benefit Pension Plans Postretirement Health (in millions) Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 Net Periodic Benefit (Credits) Costs Service costs $ 3.5 $ 3.3 $ — $ — Interest costs 24.3 30.3 4.8 6.0 Expected return on plan assets (37.5) (36.4) — — Amortization of prior service costs (credits), net (0.2) — (0.1) (0.1) Actuarial (gains) losses, net 8.9 (13.1) (1.7) 9.1 Net periodic benefit (credits) costs $ (1.0) $ (15.9) $ 3.0 $ 15.0 Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss) Amortization of prior service (costs) credits, net $ — $ — $ (2.1) $ 0.1 Prior service cost/(credit) (1.1) (1.3) — — Total recognized in other comprehensive income (loss), pre-tax $ (1.1) $ (1.3) $ (2.1) $ 0.1 Total recognized in net periodic benefit costs (income) and other comprehensive income (loss), pre-tax $ (2.1) $ (17.2) $ (0.9) $ 15.1 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 effective January 1, 2019. The benefit enhancement for 2019 has been applied to all post-65 participants regardless of past representation by the collective bargaining agreement. The increase in obligation of $10.0 million as a result of the settlement agreement was recognized in net periodic benefit costs in 2017 as a plan change resulting from a legal settlement and is reported in Nonoperating Components of Net Periodic Benefit Expense (Income) . The defined benefits pension plans were amended in March 2019 making permanent the option for pension-eligible employees to receive a lump sum payment upon termination, regardless of benefit size, which decreased plan obligations by $1.3 million. The effect of these plan changes has been added to accumulated other comprehensive income (loss) as an unrecognized prior service cost to be amortized over the average future service of active employees starting in 2020. 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 for DOE. There is the potential for additional income 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 17, Commitments and Contingencies . Assumptions Used to Determine Net Periodic Benefit Costs Defined Benefit Pension Plans Postretirement Health Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 Discount rate 2.5% 3.3% 2.5% 3.3% Expected return on plan assets 6.4% 6.8% — — 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, 2020 2019 Healthcare cost trend rate for the following year 5.5% 6.0% 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 2022 2022 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 goal of 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 and 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, 2020 2019 2021 Target Equity securities 52 % 48 % 55 - 60% Debt securities 42 % 49 % 35 - 60% Cash 6 % 3 % 0 - 5% 100 % 100 % Prefunding for the postretirement health and life benefit plans was discontinued in 2012 and the remaining assets were expended in early 2018. Benefit costs of the postretirement health and life benefit plans are funded as costs are incurred. Plan assets are measured at fair value. Following are the plan investments as of December 31, 2020 and 2019, categorized by the fair value hierarchy levels described in Note 11, Fair Value Measurements : Defined Benefit Pension Plans (in millions) Level 1 Level 2 Level 3 Total 2020 2019 2020 2019 2020 2019 2020 2019 U.S. government securities $ — $ — $ 16.4 $ 32.7 $ — $ — $ 16.4 $ 32.7 Corporate debt — — 104.2 121.1 — — 104.2 121.1 Municipal bonds and non-U.S. government securities — — 2.1 2.1 — — 2.1 2.1 Mortgage and asset backed securities — — 6.4 11.0 — — 6.4 11.0 Fair value of investments by hierarchy level $ — $ — $ 129.1 $ 166.9 $ — $ — $ 129.1 $ 166.9 Investments measured at NAV (a) 504.4 453.5 Accrued interest receivable 1.3 1.8 Unsettled transactions (1.8) (1.0) Plan assets $ 633.0 $ 621.2 (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 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 The Company expects to contribute $11.0 million to the qualified defined benefit pension plans, $0.4 million to the non-qualified defined benefit pension plans and $11.6 million to the postretirement health and life benefit plans in 2021. 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 2021 $ 53.8 $ 11.6 2022 52.1 11.1 2023 50.9 10.6 2024 49.3 10.0 2025 47.9 9.4 2026 to 2030 223.3 38.8 Other Plans The Company 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 $1.6 million in 2020 and $1.7 million in 2019. 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 of 1986, as amended (the “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 . The Company matching contributions amounted to less than $0.1 million in 2020 and 2019.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
Stock-Based Compensation	Dec. 31, 2020
Share-based Payment Arrangement, Noncash Expense [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, 2020, there were 374,478 shares available for future awards, including approximately 120,000 shares associated with awards that were terminated or cancelled without being exercised. A summary of stock-based compensation costs follows (in millions): Year Ended December 31, 2020 2019 Notional stock units and stock appreciation rights $ 6.6 $ 1.1 Restricted stock units 0.4 0.2 Stock options 0.1 0.1 Total stock-based compensation costs $ 7.1 $ 1.4 Total recognized tax benefit $ — $ — The total recognized tax benefit is reported at the federal statutory rate net of the tax valuation allowance. Notional stock units for participating executives for the three-year period ended December 31, 2018, under the 2016 Executive Incentive Plan were paid in cash in 2019 totaling $1.0 million. Notional stock units are a component of the 2019 Executive Incentive Plan for the three-year period ending December 31, 2021 with an interim payment targeted for 2021 and the final payment targeted for 2022. Notional stock units and stock appreciation rights were granted to participating executives for the three-year period ending April 26, 2023. The notional stock units and stock appreciation rights may be payable in common stock, cash or a combination of both at the discretion of the Board of Directors. Since the awards are likely to be settled with cash payments, compensation cost for notional stock units and stock appreciation rights are re-measured each reporting period based on the trading price of the Company’s common stock and the cumulative vested costs are accrued in Accounts Payable and Accrued Liabilities or Other Long-Term Liabilities based on the anticipated payment date. Compensation cost for restricted stock units and stock options 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, 2020, there was $0.3 million of unrecognized compensation cost, adjusted for actual forfeitures, related to non-vested stock-based payments granted, of which $0.2 million relates to restricted stock units and $0.1 million relates to stock options. That cost is expected to be recognized over a weighted-average period of 12 months. 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, 2020, approximately 262,000 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. 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, 2020. Year Ended December 31, Options granted (in thousands) 100 Risk-free interest rate 1.62% Expected volatility 73% Expected option life (years) 6.5 Weighted-average grant date fair value $2.44 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, 2018 425 $4.14 6.3 $— Granted 100 $3.65 Exercised (7) $3.93 Forfeited/Cancelled — — Outstanding at December 31, 2019 518 $4.02 6.2 $1.5 Granted — — Exercised (107) $3.43 Forfeited/Cancelled — — Outstanding at December 31, 2020 411 $4.18 5.3 $7.8 Exercisable at December 31, 2020 311 $4.35 4.2 $5.8 Stock options outstanding and options exercisable at December 31, 2020, follow: Stock Exercise Price Options Outstanding (thousands) Remaining Contractual Life in Years Options Exercisable (thousands) $5.62 7 3.9 7 $4.37 288 4.2 288 $3.93 8 4.6 8 $3.65 100 8.8 — $2.68 8 5.4 8

Income Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Income Tax Expense (Benefit) The income tax expense (benefit) is as follows (in millions): Year Ended December 31, 2020 2019 Current: Federal $ — $ — State and local 0.5 0.2 Foreign — 0.1 0.5 0.3 Deferred: Federal — — State and local (1.9) — Foreign — — (1.9) — Income tax expense (benefit) $ (1.4) $ 0.3 Deferred Taxes Future tax consequences of temporary differences between the carrying amounts for financial reporting purposes and the Company’s estimate of the tax bases of its assets and liabilities result in deferred tax assets and liabilities, as follows (in millions): December 31, 2020 2019 Deferred tax assets: Employee benefits costs $ 61.8 $ 65.3 Inventory 16.2 17.8 Property, plant and equipment 197.8 182.3 Net operating loss and credit carryforwards 211.1 190.9 Accrued expenses 2.1 4.2 Long-term debt and financing costs 12.6 13.2 Lease liability 1.5 2.0 Other 0.2 0.2 Deferred tax assets 503.3 475.9 Valuation allowance (486.0) (459.5) Deferred tax assets, net of valuation allowance $ 17.3 $ 16.4 Deferred tax liabilities: Intangible assets $ 13.9 $ 14.7 Lease asset 1.1 1.5 Prepaid expenses 0.4 0.2 Deferred tax liabilities $ 15.4 $ 16.4 Net deferred tax asset $ 1.9 $ — The valuation allowance reduces the net deferred tax assets to their net realizable value. 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. The Company has maintained a full valuation allowance against federal and state net deferred tax assets since the fourth quarter of 2011. In the second quarter of 2020, we released the valuation allowance against the state net deferred tax assets for the LEU segment that most likely will be realized. However, we continue to maintain a full valuation allowance against our federal and state net deferred tax assets for the rest of our business due to cumulative three-year pre-tax losses and significant federal and state net operating losses. The net deferred tax assets and related valuation allowance have been increased as of December 31, 2020 by $39.5 million for previously unrecorded state deferred tax assets, net of federal benefit, in states where we have had historical losses and a remote likelihood of realizing a tax benefit. This increase to state deferred tax assets net of the full valuation allowance has no net impact on income tax expense for 2020. We will continue to monitor profitability to determine whether we release the valuation allowance against our federal and remaining state net deferred tax assets. Based upon current and forecasted pre-tax income, we believe it is reasonably possible that sufficient positive evidence may become available to allow us to conclude that some or a significant portion of the federal valuation allowance will no longer be needed within the next 12 months. The exact timing and amount of the valuation allowance release are dependent upon the actual level of profitability that is achieved as well as the analysis of other positive and negative evidence. When a change in 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. The Company records the impact of the change in its consolidated financial statements in the period of enactment. The Company has federal net operating losses of $749.2 million generated through December 31, 2017 that currently expire through 2037. In addition, the Company has federal net operating losses and business interest expense carry forwards of $131.4 million and $11.2 million, respectively, generated after December 31, 2017, that do not expire. The Company has concluded that a full valuation allowance is needed for all federal net operating losses. Centrus also has state net operating losses of $3.9 million, with no valuation allowance, that we expect will be used in the next 12 months and state net operating losses of $454.6 million, with a full valuation allowance, that currently expire through 2035. Effective Tax Rate A reconciliation of income taxes calculated based on the federal statutory income tax rate and the effective tax rate follows: Year Ended December 31, 2020 2019 Federal statutory tax rate 21 % 21 % Valuation allowance against net deferred tax assets (26) (18) State rate changes (1) 1 Executive compensation 2 (2) State income tax expense, net of federal benefit — (1) Uncertain tax positions 1 (1) Other non-deductible expenses — (1) Effective tax rate (3) % (1) % The effective tax rate for the year ended December 31, 2020 includes a decrease to the valuation allowance against net deferred tax assets of $13.9 million, or a change to the effective tax rate of (26)%. Included in the valuation allowance decrease is the release of the valuation allowance against state net deferred taxes of $2.0 million, or a change to the effective tax rate of (4)%. The effective tax rate for the year ended December 31, 2019 includes an increase to the valuation allowance against net deferred tax assets of $3.1 million, or a change to the effective tax rate of (18)%. 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 $0.8 million as of December 31, 2020 and $0.4 million as of December 31, 2019. 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) increased $0.4 million and $0.2 million during the years ended December 31, 2020 and December 31, 2019, respectively. 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, 2020 2019 Balance at beginning of the period $ 0.4 $ 0.2 Additions to tax positions of current period 0.5 0.3 Reductions to tax positions of prior years (0.1) (0.1) Balance at end of the period $ 0.8 $ 0.4 Centrus and its subsidiaries file income tax returns with the U.S. government and various states and foreign jurisdictions. As of December 31, 2020, the federal, Maryland and Tennessee statutes of limitation are closed with respect to all tax years through 2016. 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 S elling, General and Administrative in the consolidated statement of operations. The impact of accrued interest and penalties for income taxes in the consolidated statement of operations was an increase to expenses of less than $0.1 million for the year ended December 31, 2020, and a reduction to expenses of less than $0.1 million for the year ended December 31, 2019. 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, 2020 and 2019.

Net Income Per Share

Net Income Per Share	12 Months Ended
Net Income Per Share	Dec. 31, 2020
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	NET INCOME (LOSS) PER COMMON 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. On November 17, 2020, the Company completed the purchase of 62,854 shares of its outstanding Series B Preferred Stock at a price per share of $954.59, less any applicable withholding taxes. (Refer to Note 16 - Stockholders’ Equit y). The purchase price per share represented a 25% discount from the aggregate liquidation preference, including accrued but unpaid dividends, of $1,272.78 per share as of September 30, 2020. Since origination, the carrying value on the Balance Sheet was $43.80 per share based on values assigned in the originating securities exchange. The liquidation amount at origination was $1,000.00 per share. The aggregate purchase price of approximately $60 million, less accrued but unpaid dividends attributable to the purchased and retired Series B preferred shares, is considered for purposes of Net Income per Share to be a deemed dividend to the extent it exceeds the carrying value on the Balance Sheet, or $41.9 million. The weighted average number of common and common equivalent shares and the calculation of basic and diluted income (loss) per common share are as follows: Year Ended 2020 2019 Numerator (in millions): Net income (loss) $ 54.4 $ (16.5) Preferred stock dividends - undeclared and cumulative 6.7 7.8 Distributed earnings allocable to retired preferred shares 41.9 $ — Net income (loss) allocable to common stockholders $ 5.8 $ (24.3) Denominator (in thousands): Average common shares outstanding - basic 9,825 9,566 Potentially dilutive shares related to stock options and restricted stock units (a) 298 — Average common shares outstanding - diluted 10,123 9,566 Net income (loss) per common share (in dollars): Basic $ 0.59 $ (2.54) Diluted $ 0.57 $ (2.54) (a) Common stock equivalents excluded from the diluted calculation as a result of a net loss in the period (in thousands) — 67 Options outstanding and considered anti-dilutive as their exercise price exceeded the average share market price (in thousands) — 352

Stockholders' Equity

Stockholders' Equity	12 Months Ended
Stockholders' Equity	Dec. 31, 2020
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”). As of December 31, 2020, the Company has issued 12,109,389 shares of Common Stock, consisting of 11,390,189 shares of Class A Common Stock and 719,200 shares of Class B Common Stock. On September 1, 2020, the Company completed the sale of 2,537,500 shares of the Company’s Class A common stock pursuant to the Registration Statement on Form S-3 that became effective on August 5, 2020, as supplemented by the prospectus supplement filed with the SEC on August 21, 2020. The price to the public in this offering was $10.00 per share of Common Stock. The aggregate gross proceeds from the offering were approximately $25.4 million, before deducting underwriting discounts and commissions and other estimated offering expenses payable by the Company of $2.3 million. On December 31, 2020, the Company entered into an At Market Sales Agreement with B. Riley Securities, Inc. and Lake Street Capital Markets, LLC, relating to the at the market offering of shares of the Company’s Class A Common Stock, $0.10 par value per share. For further details, refer to Note 21, Subsequent Events . Shares of Class B Common Stock that are sold in the market are automatically converted to shares of Class A Common Stock. Shares of Class B Common Stock that were sold in the market and converted to shares of Class A Common Stock totaled 398,262 in 2020 and 288,620 in 2019. The Company has reserved 1,200,000 shares of Class A Common Stock under its management incentive plan, of which 374,478 shares are available for future awards as of December 31, 2020. Refer to Note 13, 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 In 2017, Centrus issued 104,574 shares of Series B Preferred Stock as part of a securities exchange. 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”). As of December 31, 2019, the Series B Preferred Stock was recorded on the consolidated balance sheet at the original fair value less transaction costs, or $4.6 million. On November 17, 2020, pursuant to a tender offer announced on October 19, 2020, the Company completed the purchase of 62,854 shares of its outstanding Series B Preferred Stock at a price per share of $954.59, less any applicable withholding taxes, for an aggregate purchase price of approximately $60 million. The purchase price per share represented a 25% discount from the aggregate liquidation preference, including accrued but unpaid dividends, of $1,272.78 per share as of September 30, 2020. These shares represented approximately 60% of the Company's outstanding Series B Preferred Shares as of September 30, 2020. The remaining Series B Preferred shares outstanding after the transaction was 41,720 shares. On December 22, 2020, Centrus Energy Corp. (the “Company”) filed with the Delaware Secretary of State a Certificate of Retirement of 62,854 Series B Senior Preferred Stock, par value $1.00 per share (the “Series B Preferred Shares”), to effect the retirement of the Company’s Series B Preferred Shares repurchased upon the completion of its previously announced tender offer to purchase Series B Preferred Shares. Effective upon filing, the Certificate of Retirement amended the Amended and Restated Certificate of Incorporation of the Company to reduce the total number of authorized Series B Preferred Shares by 62,854 shares such that the total number of authorized Series B Preferred Shares of the Company is 41,720 shares. Holders of the Series B Preferred Stock are entitled to cumulative dividends 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 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, 2020, and has not declared, accrued or paid dividends on the Series B Preferred Stock as of December 31, 2020. 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, 2020, the Series B Preferred Stock has an aggregate liquidation preference of $53.9 million including accumulated dividends of $12.1 million. As of December 31, 2019, the Series B Preferred Stock had an aggregate liquidation preference of $127.2 million, including accumulated dividends of $22.6 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, which was (a) amended on February 14, 2017 to, among other things, exclude acquisitions of the Series B Preferred Stock issued as part of the exchange offer and consent solicitation from the definition of “Common Shares” in connection with the settlement and completion of the exchange offer and consent solicitation, and (b) further amended on April 3, 2019 to, among other things, (i) decreased the purchase price for each one one-thousandth (1/1000th) of a share of the Company’s Series A Participating Cumulative Preferred Stock, par value $1.00 per share, from $26.00 to $18.00 and (ii) extended the Final Expiration Date (as defined in the Rights Agreement) from April 5, 2019 to April 5, 2022 (as amended, 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. 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. On April 8, 2020, the Company’s Board of Directors approved, and the Company entered into, a Third Amendment to the Rights Agreement (the “Third Amendment”). The Third Amendment modified the Final Expiration Date (as defined in the Rights Agreement) to be June 30, 2021. Shares Outstanding Changes in the number of shares outstanding are as follows: Preferred Stock, Common Stock, Common Stock, Balance at December 31, 2018 104,574 8,031,307 1,406,082 Stock-based compensation - vested share grant — 20,000 — Stock-based compensation - options exercised — 7,500 — Conversion of common stock from Class B to Class A — 288,620 (288,620) Balance at December 31, 2019 104,574 8,347,427 1,117,462 Issuance under public offering — 2,537,500 — Stock-based compensation - options exercised — 107,000 — Conversion of common stock from Class B to Class A — 398,262 (398,262) Purchase under tender offer (62,854) — — Balance at December 31, 2020 41,720 11,390,189 719,200 Refer to Note 21, Subsequent Events

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Commitments under SWU Purchase Agreements TENEX A major supplier of SWU to the Company is the Russian government entity TENEX, Joint-Stock Company (“TENEX”). Under a 2011 agreement with TENEX, as amended, (the “TENEX Supply Contract”), 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 the Company obtains from TENEX under the agreement is subject to quotas and other restrictions applicable to commercial Russian LEU. The TENEX Supply Contract was originally signed with commitments through 2022 but was modified in 2015 to give the Company the right to reschedule certain quantities of SWU of the original commitments into the period 2023 and beyond, in return for the purchase of additional SWU in those years. The Company has exercised this right to reschedule in each year through December 31, 2019. If the Company exercises this right to reschedule in full during the remaining years of the contract’s original term, the Company will have a rescheduled post-2022 purchase commitment through 2028. The TENEX Supply Contract 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. In such a case, the Company would pay for the SWU but have to take the unordered SWU in the following year. Pricing terms for SWU under the TENEX Supply Contract are based on a combination of market-related price points and other factors. This formula was subject to an adjustment at the end of 2018 that reduced the unit costs of SWU under this contract in 2019 and for the duration of the contract. Orano On April 27, 2018, the Company entered into an agreement (the “Orano Supply Agreement”) with the French company Orano Cycle (“Orano”) for the long-term supply to the Company of SWU contained in LEU. Under the Orano Supply Agreement, as amended, the supply of SWU commences in 2020 and extends to 2028. The Company has the option to extend the supply period for an additional two years. The Orano Supply Agreement provides significant flexibility to adjust purchase volumes, subject to annual minimums and maximums in fixed amounts that vary year by year. Under the Orano Supply Agreement, the Company purchases SWU contained in LEU received from Orano, and the Company delivers natural uranium to Orano for the natural uranium feed material component of LEU. The pricing for the SWU purchased by the Company is determined by a formula that uses a combination of market-related price points and other factors and is subject to certain floors and ceilings. Milestones Under the 2002 DOE-USEC Agreement The Company’s predecessor USEC Inc. 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. In connection with the plan of reorganization in USEC Inc.’s 2014 Chapter 11 bankruptcy (now completed) and its emergence as the Company, 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 the Company under those agreements. The 2002 DOE-USEC Agreement requires Centrus to develop, demonstrate and deploy advanced enrichment technology in accordance with milestones, including the deployment of a commercial American Centrifuge Plant, and provides for remedies in the event of a failure to meet a milestone under certain circumstances, including terminating the 2002 DOE-USEC Agreement, revoking Centrus’ access to DOE’s centrifuge technology that is required for the success of the Company’s ongoing work with the American Centrifuge technology, 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 technology. 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 the American Centrifuge Plant milestone under the 2002 DOE-USEC Agreement, DOE and the Company will jointly meet to discuss in good faith possible adjustments to the milestones as appropriate to accommodate the delaying event. The assumption of the 2002 DOE-USEC Agreement in 2014 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 the Company have agreed that all rights, remedies and defenses of the parties with respect to any missed milestones and all other matters under the 2002 DOE-USEC Agreement continue to be preserved, and that the time limits for each party to respond to any missed milestones continue to be tolled. Legal Matters From time to time, the Company is involved in various pending legal proceedings, including the pending legal proceedings described below. On August 30, 2013, the Company submitted a claim to DOE under the Contract Disputes Act for payment of $42.8 million, representing DOE’s share of pension and postretirement benefits costs related to the transition of employees at the former Portsmouth, Ohio, Gaseous Diffusion Plant (the “Portsmouth GDP”) to DOE’s decontamination and decommissioning contractor. On August 27, 2014, the DOE contracting officer denied the Company’s claim. As a result, the Company filed an appeal of the decision in the U.S. Court of Federal Claims in January 2015. Centrus believes that DOE is responsible for a significant portion of any pension and postretirement benefit costs associated with the transition of employees at Portsmouth. On January 13, 2021, the Company and DOE reached a tentative agreement to settle the litigation, which is subject to the approval by DOE, the DOJ, the Company’s Board of Directors, and the Court. If the settlement is ultimately approved by all parties, DOE is expected to pay the Company $43.5 million (inclusive of any interest due). Any amounts received by the Company in connection with the settlement will be applied to pension and postretirement benefits obligations. The Company can give no assurance whether or when the tentative settlement will receive the required approvals or whether the Company will ultimately recover some, all or none of the proposed settlement amount. On May 26, 2019, the Company, Enrichment Corp., and six other DOE contractors who have operated facilities at the Portsmouth GDP site (including, in the case of the Company, the American Centrifuge Plant site located on the premises) were named as defendants in a class action complaint filed by Ursula McGlone, Jason McGlone, Julia Dunham, and K.D. and C.D., minor children by and through their parent and natural guardian Julia Dunham (collectively, the “McGlone Plaintiffs”) in the U.S. District Court in the Southern District of Ohio, Eastern Division. The complaint seeks damages for alleged off-site contamination allegedly resulting from activities on the Portsmouth GDP site. The McGlone Plaintiffs are seeking to represent a class of (i) all current or former residents within a seven-mile radius of the Portsmouth GDP site and (ii) all students and their parents at the Zahn’s Corner Middle School from 1993-present. The complaint was amended on December 10, 2019 and on January 10, 2020, to add additional plaintiffs and new claims. On July 31, 2020, the court granted in part and denied in part the defendants’ motion to dismiss the case. The court dismissed ten of the fifteen claims and allowed the remaining claims to proceed to the next stage of the litigation process. On August 18, 2020, the McGlone Plaintiffs filed a motion for leave to file a third amended complaint and notice of dismissal of three of the individual plaintiffs. On September 29, 2020, the defendants filed their response in opposition to the plaintiff’s motion for leave to file a third amended complaint. On October 26, 2020, the plaintiffs filed their reply brief. As of this filing, the court has not made a ruling. On March 18, 2021, the McGlone Plaintiffs filed a motion for leave to file a fourth amended complaint to add new plaintiffs and allegations. Th e Company believes that its operations at the Portsmouth GDP site were fully in compliance with the Nuclear Regulatory Commission’s regulations. Further, the Company believes that any such liability should be covered by indemnification under the Price-Anderson Nuclear Industries Indemnity Act (“Price-Anderson Act”). The Company and Enrichment Corp. have provided notifications to DOE required to invoke indemnification under the Price-Anderson Act and other contractual provisions. On November 27, 2019, the Company, Enrichment Corp. and six other DOE contractors who have operated facilities at the Portsmouth GDP site were named as defendants (“Matthews Defendants”) in a class action complaint filed by James Matthews, Jennifer Brownfield Clark, Joanne Ross, the Estate of A.R., and others similarly situated (the “Matthews Plaintiffs”), in the Common Pleas Court of Pike County, Ohio. On January 3, 2020, the complaint was removed to the U.S. District Court in the Southern District of Ohio for adjudication. The complaint sought injunctive relief, compensatory damages, statutory damages, and any other relief allowed by law for alleged off-site contamination allegedly resulting from activities on the Portsmouth GDP site. The Matthews Plaintiffs expressly contended that the ongoing and continuous releases that injured the Plaintiffs and Class Members were not “nuclear incidents” as that term is defined in the Price-Anderson Act, but rather “freestanding state law claims concerning traditional-style state regulation.” On July 27, 2020, the court granted the Company, Enrichment Corp. and the other defendants’ motion to dismiss the complaint because the Matthews Plaintiffs had opted not to proceed under the Price-Anderson Act which preempts state law. On August 18, 2020, the plaintiffs filed a notice of appeal to the U.S. Court of Appeals for the Sixth Circuit. On November 17, 2020, the Matthews Plaintiffs filed their appellant brief and on February 1, 2021, the Matthews Defendants filed their brief. On February 22, 2021, the Matthews Plaintiffs filed their reply brief. The Company believes that its operations at the Portsmouth GDP site were fully in compliance with the Nuclear Regulatory Commission’s regulations. Further, the Company believes that any such liability should be covered by indemnification under the Price-Anderson Act. The Company and Enrichment Corp. had provided notifications to DOE required to invoke indemnification under the Price-Anderson Act and other contractual provisions. On June 30, 2020, the Company, Enrichment Corp., six other DOE Contractors, DOE and other government agencies were given notice of Ursula McGlone, Jason McGlone and Julia Dunham’s intent to file a citizen’s suit under the Clean Air Act, the Clean Water Act, the Resource Conservation and Recovery Act and the Comprehensive Environmental Response, Compensation and Liability Act against the Company, Enrichment Corp. and six other DOE Contractors. The complainants will purportedly seek civil penalties and injunctive relief for alleged off-site contamination allegedly resulting from activities on the Portsmouth GDP site. As of this filing, neither the Company nor Enrichment Corp. have been served with this complaint. On September 3, 2020, the Company, Enrichment Corp., nine other DOE contractors who have operated facilities at the Portsmouth GDP site and eleven individuals in their personal capacity some of whom are current and former DOE employees were named as defendants in a class action complaint filed by Jeffrey Walburn, Charles O. Lawson Jr., Kimberly M. Lawson, James A. Brogdon, Stephen Patrick Spriggs, Donald Slone, Vicki P. Slone, Victoria Slone Moore, Toni West, Carl R. Hartley, Heather R. Hartley, Vina Colley, Antony Preston, David B. Rose, Michael E. Groves, George W. Clark, Estate of Kathy Sue Brogdon (deceased), Estate of Jay Paul Brogdon (deceased), and Jon Doe(s), and Jane Doe(s), on behalf of themselves and all similarly situated individuals (“Walburn Plaintiffs”) in the U.S. District Court in the Southern District of Ohio, Eastern Division. The complaint alleges that the named defendants conspired and concealed nuclear incidents in violation of the Price-Anderson Act, the Racketeer Influenced and Corrupt Organization Act and other state claims. The complainants seek damages and equitable and injunctive relief arising from economic losses, property losses, and non-economic damages resulting from toxic and radioactive releases from the Portsmouth GDP. On November 20, 2020, Walburn Plaintiffs filed an amended complaint to add two individuals to the complaint as defendants in their individual capacity. One of those individuals is Daniel Poneman, Centrus’ Chief Executive Officer. In the 78 page complaint, Mr. Poneman is referenced twice without any cited allegations against him; once in the caption and once referencing his position at the Company. The Company has notified its insurance carrier regarding the claim. On February 11, 2021, the Walburn Plaintiffs amended their complaint for a second time to replace two corporate defendants with two others (one of whom is a former contractor to Enrichment Corp. and also to its predecessor prior to its privatization in 1998 and the other a former DOE contractor) and removed four named individual defendants from the complaint. On March 2, 2021, Walburn Defendants filed their motion to dismiss. The Company believes that its operations at the Portsmouth GDP site were fully in compliance with the Nuclear Regulatory Commission’s regulations. Further, the Company believes that any such liability should be covered by indemnification under the Price-Anderson Act. The Company and Enrichment Corp. have provided notifications to DOE required to invoke indemnification under the Price-Anderson Act and other contractual provisions. In June 2020, the Company’s subsidiaries, Enrichment Corp. and American Centrifuge Enrichment, LLC (collectively, the “Company Subsidiaries”) collected approximately $32.4 million as a recovery on claims filed in October 2018 in the U.S. Bankruptcy Court for the Northern District of Ohio (the “Bankruptcy Court”) against each of FirstEnergy Nuclear Operating Company and FirstEnergy Nuclear Generation, LLC (collectively, the “FirstEnergy Contract Parties”). An additional $0.2 million recovery on the claims was collected in December 2020. The claims related to damages arising from the rejection and breach of a long-term contract between the Company Subsidiaries and the FirstEnergy Contract Parties in connection with bankruptcy petitions filed by the FirstEnergy Contract Parties. The recovery resulted from a May 2020 stipulation, subsequently approved by the Bankruptcy Court, whereby the FirstEnergy Contract Parties and the Company Subsidiaries agreed that the claims of the Company Subsidiaries against the FirstEnergy Contract Parties will be allowed for all purposes as an allowed unsecured claim in the amount of $70 million. Pursuant to the approved stipulation, the Company Subsidiaries dismissed their appeal concerning the disallowance by the Bankruptcy Court of claims by the Company Subsidiaries under guaranties issued by affiliates of the FirstEnergy Contract Parties, and the successors to the FirstEnergy Contract Parties entered into a contract to purchase separative work units in the future from Enrichment Corp. 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, other than the above, Centrus does not believe that the outcome of any of these legal matters, individually and in the aggregate, will have a material adverse effect on its cash flows, results of operations or consolidated financial condition.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
Accumulated Other Comprehensive Income (Loss)	Dec. 31, 2020
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. In 2019, the effect of pension plan changes related to lump sum payment options has been added to AOCI as an unrecognized prior service cost to be amortized over the average future service of active employees starting in 2020. For further details, refer to Note 12, Pension and Postretirement Health and Life Benefits

Segment Information

Segment Information	12 Months Ended
Segment Information	Dec. 31, 2020
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 (in millions): Year Ended December 31, 2020 2019 United States $ 171.7 $ 152.4 Foreign: Belgium 35.8 21.5 Japan 23.4 23.4 Other 16.3 12.4 Total foreign 75.5 57.3 Total revenue $ 247.2 $ 209.7 * less than 10% The U.S. government and its contractors, in the Company’s technical solutions segment, represented approximately 21% of total revenue in 2020 and 19% in 2019. The ten largest customers in the Company’s LEU segment represented approximately 71% of total revenue in 2020. Revenue from Synatom, Energy Harbor Nuclear Corp. and Dominion Energy South Carolina represented approximately 14%, 13% and 10%, respectively, of total revenue in 2020. In 2019, the ten largest customers in the Company’s LEU segment represented approximately 79% of total revenue. Revenue from Florida Power and Light, Dominion Energy South Carolina, Tohoku Electric Power Company, Inc. and Synatom represented approximately 27%, 12%, 11%, 10%, respectively, of total revenue in 2019. No other customer represented more than 10% of total revenue in 2020 or 2019. Centrus has two reportable segments: the LEU segment with two components, SWU and uranium, and the technical solutions 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 technical solutions segment includes revenue and cost of sales for work that Centrus performs under the HALEU Contract. The technical solutions 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 following table presents the Company’s segment information (in millions): Year Ended 2020 2019 Revenue LEU segment: Separative work units $ 151.5 $ 123.7 Uranium 39.0 45.7 Total 190.5 169.4 Technical solutions segment 56.7 40.3 Total revenue $ 247.2 $ 209.7 Segment Gross Profit (Loss) LEU segment $ 97.8 $ 50.8 Technical solutions segment (0.2) (18.3) Gross profit $ 97.6 $ 32.5 The Company’s total assets are not presented for each reportable segment as they are not reviewed by, nor otherwise regularly provided to, the chief operating decision maker. 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, 2020, and December 31, 2019.

Quarterly Results of Operations

Quarterly Results of Operations	12 Months Ended
Quarterly Results of Operations	Dec. 31, 2020
Quarterly Results of Operations (Unaudited) [Abstract]
Quarterly Financial Information [Text Block]	QUARTERLY RESULTS OF OPERATIONS (Unaudited) (in millions, except per share data) 2020 1st Qtr. 2nd Qtr. 3rd Qtr. 4th Qtr. Year Revenue $ 45.0 $ 75.7 $ 33.6 $ 92.9 $ 247.2 Cost of sales 25.4 31.9 34.4 57.9 149.6 Gross profit (loss) 19.6 43.8 (0.8) 35.0 97.6 Advanced technology costs 0.9 0.7 0.2 1.0 2.8 Selling, general and administrative 8.5 10.4 6.7 10.4 36.0 Amortization of intangible assets 1.4 1.7 1.2 2.5 6.8 Special charges (credits) for workforce reductions (0.1) — 0.6 0.1 0.6 Other (income) expense, net — — — 0.4 0.4 Operating income (loss) 8.9 31.0 (9.5) 20.6 51.0 Nonoperating components of net periodic benefit expense (income) (2.2) (2.2) (2.2) 5.0 (1.6) Interest expense 0.1 — — — 0.1 Investment income (0.4) — (0.1) — (0.5) Income tax (benefit) expense 0.1 (0.5) (0.2) (0.8) (1.4) Net income (loss) $ 11.3 $ 33.7 $ (7.0) $ 16.4 $ 54.4 Preferred stock dividends - undeclared and cumulative 2.0 2.0 1.9 0.8 6.7 Distributed earnings allocable to retired preferred shares — — — 41.9 41.9 Net income (loss) allocable to common stockholders $ 9.3 $ 31.7 $ (8.9) $ (26.3) $ 5.8 Net income (loss) per share: Basic $ 0.97 $ 3.28 $ (0.83) $ (2.55) $ 0.59 Diluted $ 0.95 $ 3.19 $ (0.83) $ (2.55) $ 0.57 2019 1st Qtr. 2nd Qtr. 3rd Qtr. 4th Qtr. Year Revenue $ 38.7 $ 10.6 $ 104.7 $ 55.7 $ 209.7 Cost of sales 44.2 14.9 69.2 48.9 177.2 Gross profit (loss) (5.5) (4.3) 35.5 6.8 32.5 Advanced technology costs 6.6 5.1 1.3 1.6 14.6 Selling, general and administrative 8.1 7.7 8.7 9.2 33.7 Amortization of intangible assets 1.1 1.2 1.8 2.4 6.5 Special charges for workforce reductions (0.1) (2.9) 0.8 0.3 (1.9) Other (income) expense, net (0.4) (0.1) (0.2) — (0.7) Operating income (loss) (20.8) (15.3) 23.1 (6.7) (19.7) Nonoperating components of net periodic benefit expense (income) (0.1) — (0.1) (4.1) (4.3) Interest expense 1.0 1.0 0.9 0.1 3.0 Investment income (0.7) (0.7) (0.5) (0.3) (2.2) Income tax (benefit) expense (0.1) — — 0.4 0.3 Net income (loss) $ (20.9) $ (15.6) $ 22.8 $ (2.8) $ (16.5) Preferred stock dividends - undeclared and cumulative 2.0 2.0 1.9 1.9 7.8 Net income (loss) allocable to common stockholders $ (22.9) $ (17.6) $ 20.9 $ (4.7) $ (24.3) Net income (loss) per share: Basic $ (2.40) $ (1.84) $ 2.18 $ (0.49) $ (2.54) Diluted $ (2.40) $ (1.84) $ 2.17 $ (0.49) $ (2.54) The calculation of net income (loss) per share on a dilutive basis is provided in Note 15, 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.

Subsequent Event

Subsequent Event	12 Months Ended
Subsequent Event	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Event	SUBSEQUENT EVENTS As previously disclosed in our Current Report on Form 8-K filed on December 31, 2020, on that same date the Company entered into an At Market Sales Agreement (the “Sales Agreement”) with B. Riley Securities, Inc. and Lake Street Capital Markets, LLC (the “Agents”), relating to the at the market offering (the “ATM Offering”) of shares of the Company’s Class A Common Stock, $0.10 par value per share. Mr. Williams, Chairman of the Centrus Board of Directors, also serves on the board of B. Riley Financial, Inc. Mr. Williams recused himself and took no part in the selection of B. Riley or the negotiation of the terms of the Sales Agreement. The shares of Class A Common Stock were issued pursuant to the Company’s shelf registration statement on Form S-3 (File No. 333-239242), which became effective on August 5, 2020, and a prospectus supplement dated December 31, 2020 to the prospectus, dated August 5, 2020. Pursuant to the Sales Agreement, as of March 22, 2021, the Company has sold an aggregate of 1,015,211 shares of its Class A Common Stock at an average price of $22.96 for a total of $23,312,963. After expenses and commissions paid to the Agents the Company received $22,379,629. The Company currently intends to use the net proceeds from the ATM Offering for general working capital purposes, to invest in technology development and to repay outstanding debt or retire shares of its Series B Senior Preferred Stock. As previously disclosed, the Company had submitted a claim to the U.S. Department of Energy (the “DOE”) under the Contract Disputes Act for payment of $42.8 million, representing the DOE’s share of pension and postretirement benefits costs related to the transition of employees at the former Portsmouth, Ohio Gaseous Diffusion Plant to the DOE’s decontamination and decommissioning contractor. As previously disclosed in our Current Report on Form 8-K filed on January 14, 2021, on January 13, 2021, the Company and the DOE reached a tentative agreement to settle the litigation. The settlement is subject to the approval of the DOE, the U.S. Department of Justice, the Company’s Board of Directors, and the Court. If the settlement is ultimately approved by all parties, the DOE is expected to pay the Company $43.5 million (inclusive of any interest due). The Company can give no assurance whether or when the tentative settlement will receive the required approvals or whether the Company will ultimately recover some, all or none of the proposed settlement amount. For further information refer to Note 17, Commitments and Contingencies - Legal Matters . As previously disclosed in our Current Report on Form 8-K filed February 5, 2021, on February 2, 2021 the Company entered into an amendment to its existing Voting and Nomination Agreement with Mr. Morris Bawabeh, Kulayba LLC and M&D Bawabeh Foundation, Inc. (collectively, the “MB Group”) and an Exchange Agreement (as described below) whereby the MB Group agreed to support management’s recommendation on certain matters at the Company’s 2021 annual meeting of stockholders (the “Annual Meeting”) and Kulayba LLC agreed to exchange shares of the Company’s Series B Senior Preferred Stock, par value $1.00 per share (“Preferred Stock”) for shares of the Company’s Class A Common Stock, par value $0.10 per share (“Common Stock”) and a warrant to acquire additional shares of Common Stock. Pursuant to the First Amendment to the Voting and Nomination Agreement, the MB Group agreed to cause all shares of Common Stock owned of record or beneficially owned by the MB Group at the Annual Meeting to be voted in favor of (i) an amendment to extend the length of the term of the Company’s Section 382 Rights Agreement dated as of April 6, 2016, as amended to date, for two years from June 30, 2021 to June 30, 2023 and (ii) an increase of shares of Common Stock reserved for delivery under the Company’s Centrus Energy Corp 2014 Equity Incentive Plan, as amended to date, of an additional 700,000 shares of Common Stock. In connection with the entry into the Voting Agreement Amendment, the Company and Kulayba LLC also entered into an Exchange Agreement, dated February 2, 2021 (the “Exchange Agreement”), pursuant to which Kulayba LLC agreed to exchange (the “Exchange”) 3,873 shares of Preferred Stock, representing a $5,000,198 liquidation preference (including accrued and unpaid dividends), for (i) 231,276 shares of Common Stock priced at the closing market price of $21.62 on the date the Exchange Agreement was signed and (ii) a Centrus Energy Corp. Warrant to Purchase Common Stock (the “Warrant”), exercisable for 250,000 shares of Common Stock at an exercise price of $21.62 per share, which was the closing market price on the date the Exchange Agreement was signed, subject to certain customary adjustments pursuant to the terms of the Warrant. The Warrant is exercisable by Kulayba LLC for a period commencing on the closing date of the Exchange and ending, unless sooner terminated as

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2020
Summary of Significant Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation and Principles of Consolidation The consolidated financial statements of Centrus Energy Corp. (“Centrus” or the “Company”), which include the accounts of the Company, its principal subsidiary United States Enrichment Corporation (“Enrichment Corp.”) and its other subsidiaries, were prepared in conformity with generally accepted accounting principles in the U.S. (“U.S. GAAP”). Certain prior year amounts have been reclassified for consistency with the current year presentation. All material intercompany transactions have been 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, revenue and related costs, asset valuations, 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 U 235 and depleted uranium having a lower percentage of U 235 . The SWU contained in LEU is calculated using an industry standard formula based on the physics of enrichment. The amount of enrichment deemed to be contained in LEU under this formula is commonly referred to as its SWU component and the quantity of natural uranium deemed to be used in the production of LEU under this formula is referred to as its uranium or “feed” component. SWU and uranium inventory costs are determined using the 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.
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 The Company evaluates the carrying values of property, plant and equipment and identifiable intangible assets when events or changes in business circumstances indicate that the carrying amount of asset, or asset group, may not be fully recoverable. The carrying amount of a long-lived asset is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset. An impairment loss is measured as the amount by which the carrying amount of a long-lived asset, or asset group exceeds its fair value.
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’ 8.25% notes (the “8.25% Notes”) are recorded at face value and the fair value is disclosed. The estimated fair value of the 8.25% Notes is based on recent trading prices and bid/ask quotes as of or near the balance sheet date. Debt issuance costs are deferred and amortized over the life of the instrument.
Concentration Risk, Credit Risk, Policy [Policy Text Block]	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 intended to mitigate the likelihood of such exposure resulting in a loss.
Segment Reporting, Policy [Policy Text Block]	SegmentsCentrus operates two business segments: LEU, which supplies various components of nuclear fuel to utilities, and technical solutions, which provides advanced engineering, design, and manufacturing services to government and private sector customers.
Revenue Recognition, Policy	Revenue The Company accounts for a contract when it has approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and collectability of consideration is probable. Revenue for product and service sales is recognized when or as the Company transfers control of the promised products or services to the customer. Revenue is measured at the transaction price, which is based on the amount of consideration that the Company expects to receive in exchange for transferring the promised goods or services to the customer. The transaction price will include estimates of variable consideration until it is probable that a significant reversal of revenue recognized will not occur. SWU and Uranium Revenue Revenue for the Company’s LEU segment 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. Contracts with customers are primarily long-term, fixed-commitment contracts under which its customers are obligated to purchase a specified quantity of the SWU component of LEU or the SWU and uranium components of LEU. The Company’s contracts for natural uranium are generally shorter-term, fixed-commitment contracts. Revenue is recognized at the time the customer obtains control of the LEU or uranium. Customers generally obtain control of LEU at nuclear 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. Each such delivery to a customer is accounted for as a distinct performance obligation under a contract, and a contract may call for multiple deliveries over a number of periods. The contract’s transaction price is allocated to each performance obligation based on the observable standalone selling price of each distinct delivery of SWU or uranium. Utility customers in general have the option to defer receipt of uranium products purchased from the Company beyond the contractual sale period. In such cases, title to SWU and/or uranium components are transferred to the customer and a performance obligation for Centrus is created and a receivable is recorded. Cash is collected for the receivable under normal credit terms. The performance obligation is represented as Deferred Revenue on the consolidated balance sheet and the customer-titled product is classified as Deferred Costs Associated with Deferred Revenue on the consolidated balance sheet. Risk of loss remains with Centrus until the customer obtains control of the uranium product. The recognition of revenue and related cost of sales occurs at the point in time at which the customer obtains control of SWU or uranium and risk of loss of the product transfers to the customer, which may occur beyond one year. The timing of the transfer of control, 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, the Company will accept payment in the form of uranium. Revenue from the sale of SWU under such contracts is recognized at the time transfer of control of LEU occurs and is based on the fair value of the uranium at contract inception or as the quantity of uranium is finalized, if variable. The Company may also borrow SWU from customers, in which case the Company will record the SWU and the related liability for the borrowing using a projected average purchase price over the borrowing period. Amounts billed to customers for handling costs are included in sales. Handling costs are accounted for as a fulfillment cost and are included in cost of sales. The Company does not have shipping costs associated with outbound freight after control over a product has transferred to a customer. The Company’s contracts with customers do not provide for significant payment terms or financing components. Technical Solutions Revenue Revenue for the technical solutions segment, principally representing technical, manufacturing, engineering, procurement, construction and operations services offered to public and private sector customers, is recognized over the contractual period as services are rendered. The Company recognizes revenue over time as it performs on these contracts because of the continuous transfer of control to the customer. For public sector contracts, this continuous transfer of control to the customer is supported by clauses in the contract that allow the customer to unilaterally terminate the contract for convenience, pay the Company for costs incurred plus a reasonable profit and assume control of any work in progress. The Company’s private sector contracts generally contain contractual termination clauses or entitle the Company to payments for work performed to date for goods and services that do not have an alternative use. With control transferring over time, revenue is recognized based on the extent of progress towards completion of the performance obligation. A contract may contain one or more performance obligations. Two or more promises to transfer goods or services to a customer may be considered a single performance obligation if the goods or services are highly interdependent or highly interrelated such that utility of the promised goods or services to the customer includes integration services provided by the Company. The Company determines the transaction price for each contract based on the consideration it expects to receive for the products or services being provided under the contract. If transaction prices are not stated in the contract for each performance obligation, contractual prices are allocated to performance obligations based on estimated relative standalone selling prices of the promised services. The Company generally uses the cost-to-cost input method of progress for performance obligations to deliver products with continual transfer of control to the customer, because it best depicts the transfer of control to the customer that occurs as the Company incurs costs. Under the cost-to-cost method, the extent of progress towards completion is measured based on the proportion of direct costs incurred to date to the total estimated direct costs at completion of the performance obligation. Revenues are recorded proportionally as costs are incurred. For performance obligations to provide services to the customer, revenue is recognized over time based on direct costs incurred or the right to invoice method (in situations where the value transferred matches the Company’s billing rights) as the customer receives and consumes the benefits. Use of the cost-to-cost method requires the Company to make reasonably dependable estimates of costs at completion associated with the design, manufacture and delivery of products and services in order to calculate revenue. Significant judgment is used to estimate total revenue and costs at completion, particularly in the assumptions related to internal labor hours and third-party services for which a vendor invoice or quote is not yet available. As a significant change in one or more estimates could affect the profitability of the Company’s contracts, the Company reviews and updates its contract-related estimates regularly. Adjustments in estimated profits/losses are recognized under the cumulative catch-up method. Under this method, the impact of the adjustments is recognized in the period the adjustment is recognized. When estimates of total costs at completion for such an integrated, construction type contract exceed total estimates of revenue to be earned on a performance obligation related to complex equipment or related services, a provision for the remaining loss on the performance obligation is recognized in the period the loss is determined. The Company has applied the practical expedient in paragraph ASC 606-10-50-14 and does not disclose the value of remaining performance obligations under service contracts having original expected terms of one year or less. The timing of revenue recognition may differ from the timing of invoicing to customers. Progress on satisfying performance obligations under contracts with customers and the related billings and cash collections are recorded on the consolidated balance sheet as contract assets or contract liabilities. Contract balances are classified as assets or liabilities on a contract-by-contract basis at the end of each reporting period. Unbilled receivables are included in Accounts Receivable on the consolidated balance sheet and arise when the timing of cash collected from customers differs from the timing of revenue recognition, such as when contract provisions require specific milestones to be met before a customer can be billed. Those assets are recognized when the revenue associated with the contract is recognized prior to billing and derecognized when billed in accordance with the terms of the contract. To the extent billings to the customer precede the recognition of technical solutions revenue, the Company recognizes a liability included in Deferred Revenue and Advances from Customers
Advanced Technology Costs, Policy [Policy Text Block]	Advanced Technology Costs American Centrifuge and related expenses that are outside of our customer contracts are included in Advanced Technology Costs
Pension and Other Postretirement Plans, Policy [Policy Text Block]	Pension and Postretirement Health and Life Benefit PlansThe 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, 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, notional stock units, stock appreciation rights, restricted stock units, restricted stock, performance awards, dividend equivalent rights and other stock based awards. Stock-based compensation cost for options and stock-settled awards are 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. Stock-based compensation cost for awards likely to be settled with cash payments are recognized over the requisite service period and accrued as a liability and re-measured each reporting period based on the trading price of the Company’s common stock.
New Accounting Pronouncements, Policy [Policy Text Block]	New Accounting Standards Recently Adopted Accounting Standards In June 2016, the Financial Accounting Standard Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, Measurement of Credit Losses on Financial Instruments , which requires estimating all expected credit losses for certain types of financial instruments, including trade receivables, held at the reporting date based on historical experience, current conditions and reasonable and supportable forecasts. ASU 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The Company adopted this standard in the first quarter of fiscal 2020 and there was no material impact. Accounting Standards Effective in Future Periods In August 2018, the FASB issued ASU 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20),

Revenue and Contracts with Cu_2

Revenue and Contracts with Customers (Tables)	12 Months Ended
Revenue and Contracts with Customers (Tables)	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue from External Customers by Geographic Areas	The following table presents revenue from SWU and uranium sales disaggregated by geographical region, including foreign countries representing 10% or more of revenue, based on the billing addresses of customers (in millions): Year Ended December 31, 2020 2019 United States $ 115.0 $ 112.1 Foreign: Belgium 35.8 21.5 Japan 23.4 23.4 Other 16.3 12.4 Total foreign 75.5 57.3 Revenue - SWU and uranium $ 190.5 $ 169.4 Revenue by customer location, including customers in a foreign country representing 10% or more of total revenue, follows (in millions): Year Ended December 31, 2020 2019 United States $ 171.7 $ 152.4 Foreign: Belgium 35.8 21.5 Japan 23.4 23.4 Other 16.3 12.4 Total foreign 75.5 57.3 Total revenue $ 247.2 $ 209.7 * less than 10%
Contract with Customer, Asset and Liability	The following table presents changes in contract liability balances (in millions): December 31, 2020 2019 Change Accrued loss on HALEU Contract: Current - Accounts payable and accrued liabilities $ 7.0 $ 10.0 $ (3.0) Noncurrent - Other long-term liabilities $ 0.7 $ 8.3 $ (7.6) Deferred revenue - current $ 281.7 $ 243.0 $ 38.7 Advances from customers - current $ 1.5 $ 23.3 $ (21.8) Advances from customers - noncurrent $ 45.2 $ 29.4 $ 15.8

Special Charges (Tables)

Special Charges (Tables)	12 Months Ended
Special Charges (Tables)	Dec. 31, 2020
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs	Liability Year Ended Liability Charges (Credits) for Termination Benefits Paid Workforce reductions: Corporate functions $ 1.2 $ 0.6 $ (1.8) $ — Piketon facility 0.2 — (0.2) — Total $ 1.4 $ 0.6 $ (2.0) $ —

Cash, Cash Equivalents and Re_2

Cash, Cash Equivalents and Restricted Cash (Tables)	12 Months Ended
Cash, Cash Equivalents and Restricted Cash (Tables)	Dec. 31, 2020
Cash, Cash Equivalents and Restricted Cash [Abstract]
Schedule of Cash and Cash Equivalents	The following table summarizes the Company’s cash, cash equivalents and restricted cash as presented on the consolidated balance sheet to amounts on the consolidated statement of cash flows (in millions): December 31, 2020 2019 Cash and cash equivalents $ 152.0 $ 130.7 Deposits for financial assurance - current 0.2 0.2 Deposits for financial assurance - noncurrent 5.7 5.7 Total cash, cash equivalents and restricted cash $ 157.9 $ 136.6
Restrictions on Cash and Cash Equivalents	The following table provides additional detail regarding the Company’s deposits for financial assurance (in millions): December 31, 2020 December 31, 2019 Current Long-Term Current Long-Term Workers compensation — 5.4 — 5.4 Other 0.2 0.3 0.2 0.3 Total deposits for financial assurance $ 0.2 $ 5.7 $ 0.2 $ 5.7

Inventories (Tables)

Inventories (Tables)	12 Months Ended
Inventories (Tables)	Dec. 31, 2020
Inventory, Net [Abstract]
Schedule of Inventories	Components of inventories are as follows (in millions): December 31, 2020 December 31, 2019 Current Current Inventories, Net Current Current Inventories, Net Separative work units $ 17.0 $ 4.6 $ 12.4 $ 7.8 $ — $ 7.8 Uranium 47.8 0.3 47.5 56.7 5.6 51.1 Total $ 64.8 $ 4.9 $ 59.9 $ 64.5 $ 5.6 $ 58.9

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
Property, Plant and Equipment (Tables)	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	A summary of changes in property, plant and equipment follows (in millions): December 31, Additions / (Depreciation) December 31, Land $ 1.2 $ — $ 1.2 Buildings and leasehold improvements 2.5 1.4 3.9 Machinery and equipment 1.1 0.3 1.4 Other 1.1 — 1.1 Property, plant and equipment, gross 5.9 1.7 7.6 Accumulated depreciation (2.2) (0.5) (2.7) Property, plant and equipment, net $ 3.7 $ 1.2 $ 4.9

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
Intangible Assets (Tables)	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets and Excess Reorganization Value [Table Text Block]	Intangible asset balances are as follows (in millions): December 31, 2020 December 31, 2019 Gross Carrying Amount Accumulated Amortization Net Amount Gross Carrying Amount Accumulated Amortization Net Amount Sales order book $ 54.6 $ 32.0 $ 22.6 $ 54.6 $ 29.9 $ 24.7 Customer relationships 68.9 28.7 40.2 68.9 24.1 44.8 Total $ 123.5 $ 60.7 $ 62.8 $ 123.5 $ 54.0 $ 69.5

Accounts Payable and Accrued _2

Accounts Payable and Accrued Liabilities (Tables)	12 Months Ended
Accounts Payable and Accrued Liabilities (Tables)	Dec. 31, 2020
Accounts Payable and Accrued Liabilities [Abstract]
Schedule of Accounts Payable and Accrued Liabilities [Table Text Block]	Components of accounts payable and accrued liabilities follow (in millions): December 31, 2020 2019 Trade payables $ 4.9 $ 7.0 Compensation and employee benefits 22.2 13.1 Postretirement health and life benefit obligations - current 11.6 14.2 Accrued HALEU Contract loss - current 7.0 10.0 Operating lease liability 2.4 2.5 Severance — 1.4 Other accrued liabilities 2.5 2.5 Total accounts payable and accrued liabilities $ 50.6 $ 50.7

Debt Schedule of Debt (Tables)

Debt Schedule of Debt (Tables)	12 Months Ended
Debt Schedule of Debt (Tables)	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Debt	A summary of debt follows (in millions): December 31, 2020 December 31, 2019 Maturity Current Long-Term Current Long-Term 8.25% Notes: Feb. 2027 Principal $ — $ 74.3 $ — $ 74.3 Interest 6.1 33.7 6.1 39.8 Total $ 6.1 $ 108.0 $ 6.1 $ 114.1

Leases (Tables)

Leases (Tables)	12 Months Ended
Leases (Tables)	Dec. 31, 2020
Leases [Abstract]
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	The table below reconciles undiscounted payments for operating leases with terms greater than 12 months to the operating lease liabilities recorded on the balance sheet (in millions). 2021 $ 3.2 2022 1.8 2023 1.0 2024 1.0 2025 1.0 Thereafter 1.8 Total lease payments 9.8 Less imputed interest 3.1 Present value of lease payments $ 6.7

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
Fair Value Measurements (Tables)	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Financial Instruments Recorded at Fair Value	Financial Instruments Recorded at Fair Value (in millions): December 31, 2020 December 31, 2019 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets: Cash and cash equivalents $ 152.0 $ — $ — $ 152.0 $ 130.7 $ — $ — $ 130.7 Deferred compensation asset (a) 2.4 — — 2.4 1.8 — — 1.8 Liabilities: Deferred compensation obligation (a) $ 2.3 $ — $ — $ 2.3 $ 1.8 $ — $ — $ 1.8

Pension and Postretirement He_2

Pension and Postretirement Health and Life Benefits (Tables)	12 Months Ended
	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
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 ($ millions) Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 Changes in Benefit Obligations: Obligations at beginning of period $ 763.5 $ 733.8 $ 152.8 $ 151.6 Actuarial (gains) losses, net 56.7 59.8 (1.6) 9.1 Service costs 3.5 3.3 — — Interest costs 24.3 30.3 4.8 6.0 Benefits paid from Plan assets (56.3) (59.1) (13.6) (13.9) Benefits paid from Company assets (0.5) — — — Plan amendments — (1.3) — — Settlements (30.4) — — — Administrative expenses paid (2.9) (3.3) — — Obligations at end of period 757.9 763.5 142.4 152.8 Changes in Plan Assets: Fair value of plan assets at beginning of period 621.2 563.5 — — Actual return on plan assets 85.4 109.3 — — Company contributions 16.6 10.8 13.6 13.9 Benefits paid (56.8) (59.1) (13.6) (13.9) Settlements (30.4) — — — Administrative expenses paid (2.9) (3.3) — — Fair value of plan assets at end of period 633.1 621.2 — — Unfunded status at end of period $ (124.8) $ (142.3) $ (142.4) $ (152.8) Amounts recognized in assets and liabilities: Current liabilities $ (0.4) $ (0.5) (11.6) (14.2) Noncurrent liabilities (124.4) (141.8) (130.8) (138.6) $ (124.8) $ (142.3) $ (142.4) $ (152.8) Amounts in accumulated other comprehensive income (loss), pre-tax: Prior service cost (credit) $ (1.1) $ (1.3) $ (2.1) $ (2.3) Discount rate used to determine benefit obligations at end of period: 2.5 % 3.3 % 2.5 % 3.3 %
Schedule of Net Benefit Costs [Table Text Block]	Components of Net Periodic Benefit Costs and Other Amounts Recognized in Other Comprehensive Income (Loss) The Company reports service costs for its defined benefit pension plans and its postretirement health and life benefit plans in Cost of Sales and Selling, General and Administrative Expenses . The remaining components of net periodic benefit credits (costs) are reported as Nonoperating Components of Net Periodic Benefit Expense (Income). Defined Benefit Pension Plans Postretirement Health (in millions) Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 Net Periodic Benefit (Credits) Costs Service costs $ 3.5 $ 3.3 $ — $ — Interest costs 24.3 30.3 4.8 6.0 Expected return on plan assets (37.5) (36.4) — — Amortization of prior service costs (credits), net (0.2) — (0.1) (0.1) Actuarial (gains) losses, net 8.9 (13.1) (1.7) 9.1 Net periodic benefit (credits) costs $ (1.0) $ (15.9) $ 3.0 $ 15.0 Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss) Amortization of prior service (costs) credits, net $ — $ — $ (2.1) $ 0.1 Prior service cost/(credit) (1.1) (1.3) — — Total recognized in other comprehensive income (loss), pre-tax $ (1.1) $ (1.3) $ (2.1) $ 0.1 Total recognized in net periodic benefit costs (income) and other comprehensive income (loss), pre-tax $ (2.1) $ (17.2) $ (0.9) $ 15.1
Schedule of Assumptions Used [Table Text Block]	Assumptions Used to Determine Net Periodic Benefit Costs Defined Benefit Pension Plans Postretirement Health Year Ended December 31, Year Ended December 31, 2020 2019 2020 2019 Discount rate 2.5% 3.3% 2.5% 3.3% Expected return on plan assets 6.4% 6.8% — —
Schedule of Health Care Cost Trend Rates [Table Text Block]	Healthcare cost trend rates used to measure postretirement health benefit obligations follow: December 31, 2020 2019 Healthcare cost trend rate for the following year 5.5% 6.0% 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 2022 2022
Schedule of Allocation of Plan Assets [Table Text Block]	Plan assets are measured at fair value. Following are the plan investments as of December 31, 2020 and 2019, categorized by the fair value hierarchy levels described in Note 11, Fair Value Measurements : Defined Benefit Pension Plans (in millions) Level 1 Level 2 Level 3 Total 2020 2019 2020 2019 2020 2019 2020 2019 U.S. government securities $ — $ — $ 16.4 $ 32.7 $ — $ — $ 16.4 $ 32.7 Corporate debt — — 104.2 121.1 — — 104.2 121.1 Municipal bonds and non-U.S. government securities — — 2.1 2.1 — — 2.1 2.1 Mortgage and asset backed securities — — 6.4 11.0 — — 6.4 11.0 Fair value of investments by hierarchy level $ — $ — $ 129.1 $ 166.9 $ — $ — $ 129.1 $ 166.9 Investments measured at NAV (a) 504.4 453.5 Accrued interest receivable 1.3 1.8 Unsettled transactions (1.8) (1.0) Plan assets $ 633.0 $ 621.2
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 2021 $ 53.8 $ 11.6 2022 52.1 11.1 2023 50.9 10.6 2024 49.3 10.0 2025 47.9 9.4 2026 to 2030 223.3 38.8

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
Stock-Based Compensation (Tables)	Dec. 31, 2020
Share-based Payment Arrangement, Noncash Expense [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, 2020 2019 Notional stock units and stock appreciation rights $ 6.6 $ 1.1 Restricted stock units 0.4 0.2 Stock options 0.1 0.1 Total stock-based compensation costs $ 7.1 $ 1.4 Total recognized tax benefit $ — $ —
Share-based Compensation, Stock Options, Activity [Table Text Block]	Stock Options (thousands) Weighted Average Exercise Price Weighted Average Remaining Contractual Life in Years Aggregate Intrinsic Value (millions) Outstanding at December 31, 2018 425 $4.14 6.3 $— Granted 100 $3.65 Exercised (7) $3.93 Forfeited/Cancelled — — Outstanding at December 31, 2019 518 $4.02 6.2 $1.5 Granted — — Exercised (107) $3.43 Forfeited/Cancelled — — Outstanding at December 31, 2020 411 $4.18 5.3 $7.8 Exercisable at December 31, 2020 311 $4.35 4.2 $5.8
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]	Stock Exercise Price Options Outstanding (thousands) Remaining Contractual Life in Years Options Exercisable (thousands) $5.62 7 3.9 7 $4.37 288 4.2 288 $3.93 8 4.6 8 $3.65 100 8.8 — $2.68 8 5.4 8

Income Taxes Income Taxes (Tabl

Income Taxes Income Taxes (Tables)	12 Months Ended
Income Taxes Income Taxes (Tables)	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	The income tax expense (benefit) is as follows (in millions): Year Ended December 31, 2020 2019 Current: Federal $ — $ — State and local 0.5 0.2 Foreign — 0.1 0.5 0.3 Deferred: Federal — — State and local (1.9) — Foreign — — (1.9) — Income tax expense (benefit) $ (1.4) $ 0.3
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	Future tax consequences of temporary differences between the carrying amounts for financial reporting purposes and the Company’s estimate of the tax bases of its assets and liabilities result in deferred tax assets and liabilities, as follows (in millions): December 31, 2020 2019 Deferred tax assets: Employee benefits costs $ 61.8 $ 65.3 Inventory 16.2 17.8 Property, plant and equipment 197.8 182.3 Net operating loss and credit carryforwards 211.1 190.9 Accrued expenses 2.1 4.2 Long-term debt and financing costs 12.6 13.2 Lease liability 1.5 2.0 Other 0.2 0.2 Deferred tax assets 503.3 475.9 Valuation allowance (486.0) (459.5) Deferred tax assets, net of valuation allowance $ 17.3 $ 16.4 Deferred tax liabilities: Intangible assets $ 13.9 $ 14.7 Lease asset 1.1 1.5 Prepaid expenses 0.4 0.2 Deferred tax liabilities $ 15.4 $ 16.4 Net deferred tax asset $ 1.9 $ —
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	A reconciliation of income taxes calculated based on the federal statutory income tax rate and the effective tax rate follows: Year Ended December 31, 2020 2019 Federal statutory tax rate 21 % 21 % Valuation allowance against net deferred tax assets (26) (18) State rate changes (1) 1 Executive compensation 2 (2) State income tax expense, net of federal benefit — (1) Uncertain tax positions 1 (1) Other non-deductible expenses — (1) Effective tax rate (3) % (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, 2020 2019 Balance at beginning of the period $ 0.4 $ 0.2 Additions to tax positions of current period 0.5 0.3 Reductions to tax positions of prior years (0.1) (0.1) Balance at end of the period $ 0.8 $ 0.4

Net Income Per Share (Tables)

Net Income Per Share (Tables)	12 Months Ended
Net Income Per Share (Tables)	Dec. 31, 2020
Earnings Per Share [Abstract]
Schedule of Net Income Per Share	Year Ended 2020 2019 Numerator (in millions): Net income (loss) $ 54.4 $ (16.5) Preferred stock dividends - undeclared and cumulative 6.7 7.8 Distributed earnings allocable to retired preferred shares 41.9 $ — Net income (loss) allocable to common stockholders $ 5.8 $ (24.3) Denominator (in thousands): Average common shares outstanding - basic 9,825 9,566 Potentially dilutive shares related to stock options and restricted stock units (a) 298 — Average common shares outstanding - diluted 10,123 9,566 Net income (loss) per common share (in dollars): Basic $ 0.59 $ (2.54) Diluted $ 0.57 $ (2.54) (a) Common stock equivalents excluded from the diluted calculation as a result of a net loss in the period (in thousands) — 67 Options outstanding and considered anti-dilutive as their exercise price exceeded the average share market price (in thousands) — 352

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
Stockholders' Equity (Tables)	Dec. 31, 2020
Stockholders' Equity Attributable to Parent [Abstract]
Schedule of Stock by Class [Table Text Block]	Shares Outstanding Changes in the number of shares outstanding are as follows: Preferred Stock, Common Stock, Common Stock, Balance at December 31, 2018 104,574 8,031,307 1,406,082 Stock-based compensation - vested share grant — 20,000 — Stock-based compensation - options exercised — 7,500 — Conversion of common stock from Class B to Class A — 288,620 (288,620) Balance at December 31, 2019 104,574 8,347,427 1,117,462 Issuance under public offering — 2,537,500 — Stock-based compensation - options exercised — 107,000 — Conversion of common stock from Class B to Class A — 398,262 (398,262) Purchase under tender offer (62,854) — — Balance at December 31, 2020 41,720 11,390,189 719,200 Refer to Note 21, Subsequent Events

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
Segment Information (Tables)	Dec. 31, 2020
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Revenue from External Customers by Geographic Areas	The following table presents revenue from SWU and uranium sales disaggregated by geographical region, including foreign countries representing 10% or more of revenue, based on the billing addresses of customers (in millions): Year Ended December 31, 2020 2019 United States $ 115.0 $ 112.1 Foreign: Belgium 35.8 21.5 Japan 23.4 23.4 Other 16.3 12.4 Total foreign 75.5 57.3 Revenue - SWU and uranium $ 190.5 $ 169.4 Revenue by customer location, including customers in a foreign country representing 10% or more of total revenue, follows (in millions): Year Ended December 31, 2020 2019 United States $ 171.7 $ 152.4 Foreign: Belgium 35.8 21.5 Japan 23.4 23.4 Other 16.3 12.4 Total foreign 75.5 57.3 Total revenue $ 247.2 $ 209.7 * less than 10%
Segment Reporting Information	The following table presents the Company’s segment information (in millions): Year Ended 2020 2019 Revenue LEU segment: Separative work units $ 151.5 $ 123.7 Uranium 39.0 45.7 Total 190.5 169.4 Technical solutions segment 56.7 40.3 Total revenue $ 247.2 $ 209.7 Segment Gross Profit (Loss) LEU segment $ 97.8 $ 50.8 Technical solutions segment (0.2) (18.3) Gross profit $ 97.6 $ 32.5 The Company’s total assets are not presented for each reportable segment as they are not reviewed by, nor otherwise regularly provided to, the chief operating decision maker. 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, 2020, and December 31, 2019.

Quarterly Results of Operatio_2

Quarterly Results of Operations (Tables)	12 Months Ended
Quarterly Results of Operations (Tables)	Dec. 31, 2020
Quarterly Results of Operations (Unaudited) [Abstract]
Schedule of Quarterly Financial Information [Table Text Block]	QUARTERLY RESULTS OF OPERATIONS (Unaudited) (in millions, except per share data) 2020 1st Qtr. 2nd Qtr. 3rd Qtr. 4th Qtr. Year Revenue $ 45.0 $ 75.7 $ 33.6 $ 92.9 $ 247.2 Cost of sales 25.4 31.9 34.4 57.9 149.6 Gross profit (loss) 19.6 43.8 (0.8) 35.0 97.6 Advanced technology costs 0.9 0.7 0.2 1.0 2.8 Selling, general and administrative 8.5 10.4 6.7 10.4 36.0 Amortization of intangible assets 1.4 1.7 1.2 2.5 6.8 Special charges (credits) for workforce reductions (0.1) — 0.6 0.1 0.6 Other (income) expense, net — — — 0.4 0.4 Operating income (loss) 8.9 31.0 (9.5) 20.6 51.0 Nonoperating components of net periodic benefit expense (income) (2.2) (2.2) (2.2) 5.0 (1.6) Interest expense 0.1 — — — 0.1 Investment income (0.4) — (0.1) — (0.5) Income tax (benefit) expense 0.1 (0.5) (0.2) (0.8) (1.4) Net income (loss) $ 11.3 $ 33.7 $ (7.0) $ 16.4 $ 54.4 Preferred stock dividends - undeclared and cumulative 2.0 2.0 1.9 0.8 6.7 Distributed earnings allocable to retired preferred shares — — — 41.9 41.9 Net income (loss) allocable to common stockholders $ 9.3 $ 31.7 $ (8.9) $ (26.3) $ 5.8 Net income (loss) per share: Basic $ 0.97 $ 3.28 $ (0.83) $ (2.55) $ 0.59 Diluted $ 0.95 $ 3.19 $ (0.83) $ (2.55) $ 0.57 2019 1st Qtr. 2nd Qtr. 3rd Qtr. 4th Qtr. Year Revenue $ 38.7 $ 10.6 $ 104.7 $ 55.7 $ 209.7 Cost of sales 44.2 14.9 69.2 48.9 177.2 Gross profit (loss) (5.5) (4.3) 35.5 6.8 32.5 Advanced technology costs 6.6 5.1 1.3 1.6 14.6 Selling, general and administrative 8.1 7.7 8.7 9.2 33.7 Amortization of intangible assets 1.1 1.2 1.8 2.4 6.5 Special charges for workforce reductions (0.1) (2.9) 0.8 0.3 (1.9) Other (income) expense, net (0.4) (0.1) (0.2) — (0.7) Operating income (loss) (20.8) (15.3) 23.1 (6.7) (19.7) Nonoperating components of net periodic benefit expense (income) (0.1) — (0.1) (4.1) (4.3) Interest expense 1.0 1.0 0.9 0.1 3.0 Investment income (0.7) (0.7) (0.5) (0.3) (2.2) Income tax (benefit) expense (0.1) — — 0.4 0.3 Net income (loss) $ (20.9) $ (15.6) $ 22.8 $ (2.8) $ (16.5) Preferred stock dividends - undeclared and cumulative 2.0 2.0 1.9 1.9 7.8 Net income (loss) allocable to common stockholders $ (22.9) $ (17.6) $ 20.9 $ (4.7) $ (24.3) Net income (loss) per share: Basic $ (2.40) $ (1.84) $ 2.18 $ (0.49) $ (2.54) Diluted $ (2.40) $ (1.84) $ 2.17 $ (0.49) $ (2.54) The calculation of net income (loss) per share on a dilutive basis is provided in Note 15, 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.

Revenue and Contracts with Cu_3

Revenue and Contracts with Customers (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue, nonmonetary transaction		$ 23.4
Advances from customers, noncurrent		45.2	$ 29.4
Deferred revenue, additions in period		38.7	49.2
Deferred revenue, revenue recognized		0	10.7
Separative work units borrowed in period, value		11.2
Separative work units owed to others noncurrent		20.7
Government cost share portion		115
Company cost share portion			18.3
Government cost obligation		87.4
Provision for Loss on Contracts		7	10
Provision for loss on contracts, noncurrent		0.7	8.3
Accounts receivable, net		29.6	21.1
Gain (loss) related to litigation settlement		32.6
Revenue, remaining performance obligation, amount		960	1,000
Deferred Revenue and Advances from Customers - Current and Noncurrent		328
Contract with Customer, Liability, Revenue Recognized		44.4
Provision for loss on contract noncurrent		0.7
Provision for loss on contracts total		7.7
Provision for loss on contracts utilized		10.6
Contract revenue portion after next twelve months		4.9
Government [Member]
Proceeds from Customers		55.8
Low Enriched Uranium Segment [Member]
Revenue, remaining performance obligation, amount		$ 960	$ 1,000
Scenario, Forecast [Member]
Litigation settlement, amount awarded from other party	$ 43.5

Revenue and Contracts with Cu_4

Revenue and Contracts with Customers (Revenue from External Customers by Geographic Areas) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Revenue		$ 247.2	$ 209.7
United States
Revenue		171.7	152.4
Belgium
Revenue	$ 35.8		21.5
Japan
Revenue		23.4	23.4
Other Foreign
Revenue		16.3	12.4
Foreign
Revenue		75.5	57.3
Product [Member]
Revenue		190.5	169.4
Product [Member] \| United States
Revenue		115	112.1
Product [Member] \| Belgium
Revenue		35.8	21.5
Product [Member] \| Japan
Revenue		23.4
Product [Member] \| Other Foreign
Revenue		16.3	12.4
Product [Member] \| Foreign
Revenue		$ 75.5	$ 57.3

Revenue and Contracts with Cu_5

Revenue and Contracts with Customers (Contract with Customer Asset and Liability) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Deferred costs associated with deferred revenue	$ 151.9	$ 144.1
Provision for Loss on Contracts	7	10
Provision for loss on contract change	(3)
Provision for loss on contracts, noncurrent	0.7	8.3
Provision for loss on contracts, noncurrent, change	(7.6)
Deferred revenue	281.7	243
Deferred revenue change	38.7
Advances from customers	1.5	23.3
Advances from customers change	(21.8)
Advances from customers, noncurrent	45.2	$ 29.4
Advances from customers, noncurrent, change	$ 15.8

Revenue and Contracts with Cu_6

Revenue and Contracts with Customers Accounts Receivable (Schedule of Accounts Receivable) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Billed Contracts Receivable	$ 23	$ 13.2
Unbilled Receivables, Current	6.6	7.9
Accounts receivable, net	$ 29.6	$ 21.1

Special Charges (Table) (Detail

Special Charges (Table) (Details) - USD ($) $ in Millions	12 Months Ended
Special Charges (Table) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Termination benefit costs	$ 0.6
Payments for one-time termination benefits	(2)
Restructuring liability	0	$ 1.4
Contract Termination [Member]
Termination benefit costs	0
Payments for one-time termination benefits	(0.2)
Restructuring liability	0	0.2
Other Restructuring [Member]
Termination benefit costs	0.6
Payments for one-time termination benefits	(1.8)
Restructuring liability	$ 0	$ 1.2

Special Charges (Narrative) (De

Special Charges (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Special charges for workforce reductions and advisory costs	$ (0.1)	$ (0.6)	$ 0	$ 0.1	$ (0.3)	$ (0.8)	$ 2.9	$ 0.1	$ (0.6)	$ 1.9
Termination benefit costs									0.6
Contract Termination [Member]
Termination benefit costs									$ 0

Cash, Cash Equivalents and Re_3

Cash, Cash Equivalents and Restricted Cash (Schedule of Cash, Cash Equivalents and Restricted Cash) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 152	$ 130.7
Restricted cash included in other current assets	0.2	0.2
Restricted cash included in other long-term assets	5.7	5.7
Total cash, cash equivalents and restricted cash	$ 157.9	$ 136.6	$ 136.6	$ 159.7

Cash, Cash Equivalents and Re_4

Cash, Cash Equivalents and Restricted Cash (Schedule of Restricted Cash) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash included in other current assets	$ 0.2	$ 0.2
Restricted cash included in other long-term assets	5.7	5.7
Other financial assurance [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash included in other current assets	0.2	0.2
Restricted cash included in other long-term assets	0.3	0.3
Workers compensation financial assurance [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash included in other long-term assets	$ 5.4	$ 5.4

Cash, Cash Equivalents and Re_5

Cash, Cash Equivalents and Restricted Cash (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Restricted cash included in other current assets	$ 0.2	$ 0.2
Restricted cash included in other long-term assets	5.7	5.7
Workers compensation financial assurance [Member]
Restricted cash included in other long-term assets	$ 5.4	$ 5.4

Inventories (Schedule of Invent

Inventories (Schedule of Inventories) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Inventory, Net [Abstract]
Separative work units inventory	$ 17	$ 7.8
Uranium inventory	47.8	56.7
Inventories	64.8	64.5
Separative work units owed to customers and suppliers	4.6	0
Uranium owed to customers and suppliers	0.3	5.6
Inventories owed to customers and suppliers	4.9	5.6
Separative work units net of liability	12.4	7.8
Uranium inventory net of liability	47.5	51.1
Inventories, net	$ 59.9	$ 58.9

Inventories (Narrative) (Detail

Inventories (Narrative) (Details) $ in Millions	12 Months Ended
Inventories (Narrative) (Details) $ in Millions	Dec. 31, 2019USD ($)
Inventory, Net [Abstract]
Inventory write-down	$ 2.3
Related Party Transaction, Purchases from Related Party	$ 7.1

Property, Plant and Equipment_2

Property, Plant and Equipment (Tables) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 7.6	$ 5.9
Property, Plant and Equipment, Additions	1.7
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(2.7)	(2.2)
Depreciation	(0.5)	(0.6)
Property, Plant And Equipment, Net Capital Expenditures	1.2
Property, Plant and Equipment, Net	4.9	3.7
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	3.9	2.5
Property, Plant and Equipment, Additions	1.4
Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1.4	1.1
Property, Plant and Equipment, Additions	0.3
Other Capitalized Property Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 1.1	$ 1.1

Property, Plant and Equipment_3

Property, Plant and Equipment (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Depreciation	$ 0.5	$ 0.6
Sale price assets and property, net		0.7
Proceeds from Sale of Property, Plant, and Equipment		$ 0.7

Schedule of Intangible Assets (

Schedule of Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	$ 123.5	$ 123.5
Accumulated intangible asset amortization	(60.7)	(54)
Amortizable intangible assets, net	$ 62.8	69.5
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	(32)	(29.9)
Amortizable intangible assets, net	22.6	24.7
Customer-Related Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	68.9	68.9
Accumulated intangible asset amortization	(28.7)	(24.1)
Amortizable intangible assets, net	$ 40.2	$ 44.8

Intangible Assets Schedule of I

Intangible Assets Schedule of Intangible Asset Amortization (Details) $ in Millions	Dec. 31, 2020USD ($)
Intangible Assets Disclosure [Abstract]
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	$ 8
Finite-Lived Intangible Assets, Amortization Expense, Year Two	9.6
Finite-Lived Intangible Assets, Amortization Expense, Year Three	7.5
Finite-Lived Intangible Assets, Amortization Expense, Year Four	9.4
Finite-Lived Intangible Assets, Amortization Expense, Year Five	5.8
Finite-Lived Intangible Assets, Amortization Expense, after Year Five	22.5
Finite-Lived Intangible Assets, Net	$ 62.8

Accounts Payable and Accrued _3

Accounts Payable and Accrued Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Trade payables	$ 4.9	$ 7
Postretirement health and life benefit obligations - current	11.6	14.2
Compensation and benefits payable	22.2	13.1
Provision for Loss on Contracts	7	10
Operating Lease, Liability, Current	2.4	2.5
Accrued severance payments	0	1.4
Other accrued liabilities	2.5	2.5
Accounts payable and accrued liabilities	$ 50.6	$ 50.7

Schedule of Debt (Details)

Schedule of Debt (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term debt	$ 108	$ 114.1
Senior Notes [Member]
Debt Instrument [Line Items]
Long-term debt, face amount	74.3	74.3
Long-term debt, interest	33.7	39.8
Long-term debt, current	6.1	6.1
Long-term debt	$ 108	$ 114.1

Debt (Narrative) (Details)

Debt (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Preferred stock, shares issued	104,574
Preferred stock, liquidation preference per share	$ 1,000
Subordination to credit facility, facility total	$ 50
Subordination to credit facility, facility maximum net borrowing	$ 40
Senior Notes [Member]
Debt instrument interest rate	8.25%
Long-term debt, face amount	$ 74.3	$ 74.3
Long-term debt, current	$ 6.1	$ 6.1

Leases (Narrative) (Details)

Leases (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
Leases (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating Lease, Weighted Average Remaining Lease Term	3 years 2 months 12 days		3 years 2 months 12 days
Operating Lease, Right-of-Use Asset	$ 4.6		$ 4.6
Operating Lease, Liability, Current	2.4		2.4	$ 2.5
Operating Lease, Liability, Noncurrent	4.3		4.3
Operating Lease, Liability	6.7		6.7
Operating Lease, Expense			2.6	2.7
Operating Lease, Expense Adjustment			(0.3)	$ (0.5)
Operating Lease, Payments			3.2
Operating Lease, Liability, Increase	$ 1.4	$ 3.8
Operating Lease, Liability, Decrease			$ 0.2
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssets		us-gaap:OtherAssets	us-gaap:OtherAssets
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accounts payable and accrued liabilities		Accounts payable and accrued liabilities	Accounts payable and accrued liabilities
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other long-term liabilities		Other long-term liabilities	Other long-term liabilities

Maturity of Operating Lease Lia

Maturity of Operating Lease Liabilities (Details) $ in Millions	Dec. 31, 2020USD ($)
Leases [Abstract]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	$ 3.2
Lessee, Operating Lease, Liability, Payments, Due Year Two	1.8
Lessee, Operating Lease, Liability, Payments, Due Year Three	1
Lessee, Operating Lease, Liability, Payments, Due Year Four	1
Lessee, Operating Lease, Liability, Payments, Due Year Five	1
Lessee, Operating Lease, Liability, Payments, Due after Year Five	1.8
Lessee, Operating Lease, Liability, Payments, Due	9.8
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	3.1
Operating Lease, Liability	$ 6.7

Leases Operating Lease Liabilit

Leases Operating Lease Liabilities, Payments Due (Details) $ in Millions	Dec. 31, 2020USD ($)
Leases [Abstract]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	$ 3.2
Lessee, Operating Lease, Liability, Payments, Due Year Two	1.8
Lessee, Operating Lease, Liability, Payments, Due Year Three	1
Lessee, Operating Lease, Liability, Payments, Due Year Four	1
Lessee, Operating Lease, Liability, Payments, Due Year Five	1
Lessee, Operating Lease, Liability, Payments, Due after Year Five	1.8
Lessee, Operating Lease, Liability, Payments, Due	$ 9.8

Fair Value Measurements (Financ

Fair Value Measurements (Financial Instruments Recorded at Fair Value) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Cash and cash equivalents	$ 152	$ 130.7
Cash and cash equivalents	152	130.7
Deferred compensation asset	2.4	1.8
Deferred compensation obligation	2.3	1.8
Level 1 [Member]
Cash and cash equivalents		130.7
Deferred compensation asset	2.4	1.8
Deferred compensation obligation	$ 2.3	$ 1.8

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - Senior Notes [Member] - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, long-term and short-term, combined carrying value	$ 114.1	$ 120.2
Long-term debt, current	6.1	6.1
Long-term debt, fair value	68.6	61.5
Long-term debt, face amount	$ 74.3	$ 74.3

Pension and Postretirement He_3

Pension and Postretirement Health and Life Benefits (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Defined Benefit Plan, Accumulated Benefit Obligation	$ 757.9	$ 763.5
Expected defined benefit plan contributions for next fiscal year for qualified plans	11
Expected defined benefit plan contributions for next fiscal year for non-qualified plans	0.4
Expected defined benefit plan contributions for next fiscal year for postretirement health and life benefit plans	11.6
Defined Contribution Plan, Cost	1.6	1.7
Defined Benefit Plan, Actuarial (Gain) Loss From Remeasurement	(7.2)	4
Pension plan assets transferred for annuitization	30.4
Pension plan obligations transferred for annuitization	$ 30.4
Pension Plan, Defined Benefit [Member]
Approximate Number of Plan Participants	4,600
Defined Benefit Plan, Actuarial (Gain) Loss From Remeasurement	$ 56.7	$ 59.8
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.50%	3.30%
Other Postretirement Benefits Plan [Member]
Approximate Number of Plan Participants	2,600
Defined Benefit Plan, Actuarial (Gain) Loss From Remeasurement	$ (1.6)	$ 9.1
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.50%	3.30%

Pension and Postretirement He_4

Pension and Postretirement Health and Life Benefits (Schedule of Changes in Projected Benefit Obligations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Actuarial (Gain) Loss From Remeasurement	$ (7.2)	$ 4
Defined Benefit Plan, Plan Assets, Amount	633	621.2
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Benefit Obligation	757.9	763.5	$ 733.8
Defined Benefit Plan, Actuarial (Gain) Loss From Remeasurement	56.7	59.8
Defined Benefit Plan, Service Cost	3.5	3.3
Defined Benefit Plan, Interest Cost	24.3	30.3
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(56.8)	(59.1)
Defined Benefit Plan, Benefit Obligation, Increase for Plan Amendment	0	(1.3)
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	(30.4)	0
Defined Benefit Plan, Benefit Obligation, Administrative Expenses Paid	(2.9)	(3.3)
Defined Benefit Plan, Plan Assets, Amount	633.1	621.2	563.5
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	85.4	109.3
Defined Benefit Plan, Plan Assets, Contributions by Employer	16.6	10.8
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(124.8)	(142.3)
Amounts Recognized In Current Liabilities	(0.4)	(0.5)
Amounts Recognized In Noncurrent Liabilities	(124.4)	(141.8)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(124.8)	(142.3)
Recognized In Accumulated Other Comprehensive Income Pre Tax Prior Service Cost Credit	(1.1)	(1.3)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	$ (1.1)	$ (1.3)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.50%	3.30%
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Benefit Obligation	$ 142.4	$ 152.8	151.6
Defined Benefit Plan, Actuarial (Gain) Loss From Remeasurement	(1.6)	9.1
Defined Benefit Plan, Service Cost	0	0
Defined Benefit Plan, Interest Cost	4.8	6
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(13.6)	(13.9)
Defined Benefit Plan, Benefit Obligation, Increase for Plan Amendment	0	0
Defined Benefit Plan, Benefit Obligation, Administrative Expenses Paid	0	0
Defined Benefit Plan, Plan Assets, Amount	0	0	$ 0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	0	0
Defined Benefit Plan, Plan Assets, Contributions by Employer	13.6	13.9
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(142.4)	(152.8)
Amounts Recognized In Current Liabilities	(11.6)	(14.2)
Amounts Recognized In Noncurrent Liabilities	(130.8)	(138.6)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(142.4)	(152.8)
Recognized In Accumulated Other Comprehensive Income Pre Tax Prior Service Cost Credit	(2.1)	(2.3)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	$ (2.1)	$ 0.1
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.50%	3.30%
Plan paid [Member] \| Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Benefit Obligation, Benefits Paid	$ (56.3)	$ (59.1)
Plan paid [Member] \| Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(13.6)	(13.9)
Company paid [Member] \| Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Benefit Obligation, Benefits Paid	$ (0.5)	$ 0

Pension and Postretirement He_5

Pension and Postretirement Health and Life Benefits (Schedule of Net Benefit Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Actuarial (Gain) Loss From Remeasurement	$ (7.2)	$ 4
Pension Plan, Defined Benefit [Member]
Service costs	3.5	3.3
Interest costs	24.3	30.3
Expected return on plan assets (gains)	(37.5)	(36.4)
Amortization of prior service costs (credits), net	(0.2)	0
Actuarial (gains) losses, net	8.9	(13.1)
Defined Benefit Plan, Actuarial (Gain) Loss From Remeasurement	56.7	59.8
Net periodic benefit cost (credit)	(1)	(15.9)
Postretirement Health and Life Benefits Plans [Member]
Service costs	0	0
Interest costs	4.8	6
Expected return on plan assets (gains)	0	0
Amortization of prior service costs (credits), net	(0.1)	(0.1)
Actuarial (gains) losses, net	(1.7)	9.1
Defined Benefit Plan, Actuarial (Gain) Loss From Remeasurement	(1.6)	9.1
Net periodic benefit cost (credit)	$ 3	$ 15

Pension and Postretirement He_6

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, 2020	Dec. 31, 2019
Pension Plan, Defined Benefit [Member]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	$ (1.1)	$ (1.3)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	(1.1)	(1.3)
Total recognized in net periodic benefit costs (income) and other comprehensive income (loss), pre-tax	(2.1)	(17.2)
Other Postretirement Benefits Plan [Member]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	(2.1)	0.1
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	(2.1)	0.1
Total recognized in net periodic benefit costs (income) and other comprehensive income (loss), pre-tax	$ (0.9)	$ 15.1

Pension and Postretirement He_7

Pension and Postretirement Health and Life Benefits (Schedule of Assumptions Used) (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	2.50%	3.30%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	6.40%	6.80%
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	2.50%	3.30%

Pension and Postretirement He_8

Pension and Postretirement Health and Life Benefits (Schedule of Healthcare Cost Trend Rates) (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year	5.50%	6.00%
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	2022	2022

Pension and Postretirement He_9

Pension and Postretirement Health and Life Benefits (Plan Asset Allocations) (Details)	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		100.00%	100.00%
Equity Securities [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		52.00%	48.00%
Equity Securities [Member] \| Scenario, Forecast [Member] \| Minimum [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	55.00%
Equity Securities [Member] \| Scenario, Forecast [Member] \| Maximum [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	60.00%
Debt Securities [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		42.00%	49.00%
Debt Securities [Member] \| Scenario, Forecast [Member] \| Minimum [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	35.00%
Debt Securities [Member] \| Scenario, Forecast [Member] \| Maximum [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	60.00%
Cash [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		6.00%	3.00%
Cash [Member] \| Scenario, Forecast [Member] \| Minimum [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	0.00%
Cash [Member] \| Scenario, Forecast [Member] \| Maximum [Member]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	5.00%

Pension and Postretirement H_10

Pension and Postretirement Health and Life Benefits (Schedule of Fair Value of Plan Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
US Government Securities	$ 16.4	$ 32.7
Corporate Debt	104.2	121.1
Municipal Bonds	2.1	2.1
Mortgage and asset backed securities	6.4	11
Fair Value of Investments by Hierarchy Level	129.1	166.9
Plan investments measured at NAV	504.4	453.5
Accrued Interest Receivable	1.3	1.8
Unsettled Transactions Receivable	(1.8)	(1)
Defined Benefit Plan, Plan Assets, Amount	633	621.2
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Plan Assets, Amount	633.1	621.2	$ 563.5
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Plan Assets, Amount	0	0	$ 0
Fair Value, Inputs, Level 2 [Member]
US Government Securities	16.4	32.7
Corporate Debt	104.2	121.1
Municipal Bonds	2.1	2.1
Mortgage and asset backed securities	6.4	11
Fair Value of Investments by Hierarchy Level	$ 129.1	$ 166.9

Pension and Postretirement H_11

Pension and Postretirement Health and Life Benefits (Schedule of Estimated Future Benefit Payments) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	$ 53.8
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	52.1
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	50.9
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	49.3
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	47.9
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	$ 223.3
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months		$ 11.6
Defined Benefit Plan, Expected Future Benefit Payment, Year Two		11.1
Defined Benefit Plan, Expected Future Benefit Payment, Year Three		10.6
Defined Benefit Plan, Expected Future Benefit Payment, Year Four		10
Defined Benefit Plan, Expected Future Benefit Payment, Year Five		9.4
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter		$ 38.8

Stock-Based Compensation (Narra

Stock-Based Compensation (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2015
Common Stock, Capital Shares Reserved for Future Issuance	374,478		1,200,000
Shares for Cancelled or Forfeited Awards	120,000
Stock-based compensation paid in cash	$ 1	$ 1
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 0.3
Restricted stock units potentially converted to common stock shares	262,000
Employee Stock Option [Member]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 0.1
Restricted Stock Units (RSUs) [Member]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 0.2

Stock-Based Compensation (Stock

Stock-Based Compensation (Stock-Based Compensation Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share-based Payment Arrangement, Noncash Expense [Abstract]
Restricted Stock or Unit Expense	$ 0.4	$ 0.2
Stock or Unit Option Plan Expense	0.1	0.1
Stock Appreciation Rights Expense	6.6	1.1
Allocated Share-based Compensation Expense	$ 7.1	$ 1.4

Stock-Based Compensation Stock-

Stock-Based Compensation Stock-Based Compensation (Assumptions Used in the Black-Scholes Option Pricing Model) (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share-based Payment Arrangement, Noncash Expense [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	100	100
Share-based Goods and Nonemployee Services Transaction, Valuation Method, Risk Free Interest Rate	1.62%
Share-based Goods and Nonemployee Services Transaction, Valuation Method, Expected Volatility Rate	73.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term, Simplified Method	6.5
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 2.44

Stock-Based Compensation (Optio

Stock-Based Compensation (Options) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement, Noncash Expense [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	411,000	518,000	425,000
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 4.18	$ 4.02	$ 4.14
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	5 years 3 months 18 days	6 years 2 months 12 days	6 years 3 months 18 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	100,000	100,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price		$ 3.65
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(107,000)	(7,500)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$ 3.43	$ 3.93
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 7.8	$ 1.5
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	311,000
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 4.35
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	4 years 2 months 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	$ 5.8

Schedule of Share Based Compens

Schedule of Share Based Compensation Shares Authorized Under Stock Option Plans By Exercise Price (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 4.18	$ 4.02	$ 4.14
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	5 years 3 months 18 days	6 years 2 months 12 days	6 years 3 months 18 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	311
Option Group One [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 5.62
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options	7
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	3 years 10 months 24 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	7
Option Group Two [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 4.37
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options	288
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	4 years 2 months 12 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	288
Option Group Four [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 3.93
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options	8
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	4 years 7 months 6 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	8
Option Group Five [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 3.65
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options	100
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	8 years 9 months 18 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	0
Option Group Six [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 2.68
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options	8
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	5 years 4 months 24 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	8

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
Income Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent									(18.00%)
Increase (decrease) in deferred tax asset valuation allowance									$ 13.9	$ 3.1
Operating Loss Carryforwards												$ 749.2
Deferred Tax Assets, Operating Loss Carryforwards	$ 211.1				$ 190.9				211.1	190.9
Provision (benefit) for income taxes	0.8	$ 0.2	$ 0.5	$ (0.1)	(0.4)	$ 0	$ 0	$ 0.1	1.4	(0.3)
Liability for Uncertain Tax Positions, Noncurrent	0.8				$ 0.4				0.8	0.4	$ 0.2
Income Tax Examination, Penalties and Interest Expense Reduction									(0.1)
Unrecognized Tax Benefits, Income Tax Penalties Expense Reduction									(0.4)	$ (0.2)
Income Tax Examination, Penalties and Interest Accrued	0.1								$ 0.1
Federal Statutory Income Tax Rate, Percent									21.00%	21.00%
State and Local Jurisdiction [Member]
Deferred Tax Asset, Increase (Decrease), Amount									$ 39.5
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent									(1.00%)	1.00%
Increase (decrease) in deferred tax asset valuation allowance									$ 2
Operating Loss Carryforwards	3.9								3.9
Deferred Tax Assets, Operating Loss Carryforwards	454.6								454.6
Tax Year 2018 [Member]
Operating Loss Carryforwards	131.4								131.4
Business Interest Expense Carryforward	$ 11.2								$ 11.2

Income Taxes (Taxes by Jurisdic

Income Taxes (Taxes by Jurisdiction) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Current Income Tax Expense (Benefit)									$ 0.5	$ 0.3
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability									(1.9)	0
Provision (benefit) for income taxes	$ (0.8)	$ (0.2)	$ (0.5)	$ 0.1	$ 0.4	$ 0	$ 0	$ (0.1)	(1.4)	0.3
State and Local Jurisdiction [Member]
Current Income Tax Expense (Benefit)									0.5	0.2
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability									(1.9)	0
Foreign Tax Authority [Member]
Current Income Tax Expense (Benefit)									$ 0	$ 0.1

Income Taxes (Deferred Income T

Income Taxes (Deferred Income Taxes) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Components of Deferred Tax Assets and Liabilities [Abstract]
Deferred Tax Assets, Employee Benefits Costs	$ 61.8	$ 65.3
Deferred Tax Assets, Inventory	16.2	17.8
Deferred Tax Assets, Property, Plant and Equipment	197.8	182.3
Deferred Tax Assets, Net Operating Loss and Credit Carryforwards	211.1	190.9
Deferred Tax Assets, Accrued Expenses	2.1	4.2
Deferred Tax Assets, Long-Term Debt and Financing Costs	12.6	13.2
Deferred Tax Asset, Lease Liability	1.5	2
Deferred Tax Assets, Other	0.2	0.2
Deferred Tax Assets, Gross	503.3	475.9
Deferred Tax Assets, Valuation Allowance	(486)	(459.5)
Deferred Tax Assets, Net of Valuation Allowance	17.3	16.4
Deferred Tax Liabilities, Intangible Assets	13.9	14.7
Deferred Tax Liability, Lease Asset	1.1	1.5
Deferred Tax Liabilities, Prepaid Expenses	0.4	0.2
Deferred Tax Liabilities	15.4	16.4
Deferred Tax Assets, Net, Current	$ 1.9	$ 0

Income Taxes (Rate Reconciliati

Income Taxes (Rate Reconciliation) (Details)	12 Months Ended
Income Taxes (Rate Reconciliation) (Details)	Dec. 31, 2020	Dec. 31, 2019
Federal Statutory Income Tax Rate, Percent	21.00%	21.00%
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent	(26.00%)	(18.00%)
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent	(18.00%)
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent	2.00%	(2.00%)
Effective Income Tax Rate Reconciliation, State Income Tax Expense, Net of Federal Benefit, Percent	0.00%	(1.00%)
Effective Income Tax Rate Reconciliation, Uncertain Tax Positions	1.00%	(1.00%)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Percent	0.00%	(1.00%)
Effective Income Tax Rate Reconciliation, Percent	(3.00%)	(1.00%)
State and Local Jurisdiction [Member]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent	(1.00%)	1.00%

Income Taxes (Unrecognized Tax

Income Taxes (Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Liability for Uncertain Tax Positions, Noncurrent	$ 0.8	$ 0.4	$ 0.2
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions	0.5	0.3
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	$ (0.1)	$ (0.1)

Net Income Per Share (Narrative

Net Income Per Share (Narrative) (Details) - USD ($)	3 Months Ended				12 Months Ended
Net Income Per Share (Narrative) (Details) - USD ($)	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Preferred Stock, Liquidation Preference Per Share	$ 1,000				$ 1,000
Payments for Repurchase of Preferred Stock and Preference Stock					$ 61,600,000	$ 0
Preferred Stock Dividends and Other Adjustments	$ 41,900,000	$ 0	$ 0	$ 0	41,900,000	$ 0
Series B Preferred Stock [Member]
Payments for Repurchase of Preferred Stock and Preference Stock					$ 60,000,000
Preferred Series B [Member]
Stock Repurchased and Retired During Period, Shares					62,854
Stock Repurchase Price per Share					$ 954.59
Preferred Stock, Liquidation Amount per Share	1,272.78				1,272.78
Preferred Stock, Carrying Value per Share	$ 43.80				$ 43.80
Preferred Stock, Liquidation Preference Per Share	$ 1,000				$ 1,000
Payments for Repurchase of Preferred Stock and Preference Stock					$ 60,000,000
Preferred Stock Dividends and Other Adjustments					$ 41,900,000

Net Income Per Share (Schedule

Net Income Per Share (Schedule of Income Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Income Per Share Calculation [Line Items]
Net income (loss)	$ 16.4	$ (7)	$ 33.7	$ 11.3	$ (2.8)	$ 22.8	$ (15.6)	$ (20.9)	$ 54.4	$ (16.5)
Preferred stock dividends, undeclared and cumulative	0.8	1.9	2	2	1.9	1.9	2	2	6.7	7.8
Preferred Stock Dividends and Other Adjustments									41.9	0
Net income (loss) allocable to common stockholders	$ (26.3)	$ (8.9)	$ 31.7	$ 9.3	$ (4.7)	$ 20.9	$ (17.6)	$ (22.9)	$ 5.8	$ (24.3)
Average number of shares outstanding, basic									9,825	9,566
Potentially dilutive shares related to stock options									298	0
Average number of shares outstanding, diluted									10,123	9,566
Net income (loss) per common share - basic	$ (2.55)	$ (0.83)	$ 3.28	$ 0.97	$ (0.49)	$ 2.18	$ (1.84)	$ (2.40)	$ 0.59	$ (2.54)
Net income (loss) per common share - diluted	$ (2.55)	$ (0.83)	$ 3.19	$ 0.95	$ (0.49)	$ 2.17	$ (1.84)	$ (2.40)	$ 0.57	$ (2.54)
Antidilutive securities excluded from computation of earnings per share									0	67
Options with exercise price greater than market price									0	352

Stockholders' Equity (Tables) (

Stockholders' Equity (Tables) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Conversion of Stock, Shares Converted	398,262	288,620
Stock issued during period	$ 23.1
Common Stock, Shares, Issued	12,109,389
Preferred Stock, Shares Issued	104,574
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	107,000	7,500
Preferred Stock, Shares Outstanding	41,720	104,574	104,574
Preferred Series B [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	41,720	104,574
Stock Repurchased and Retired During Period, Shares	(62,854)
Preferred Stock, Shares Outstanding	41,720
Common Class A [Member]
Class of Stock [Line Items]
Common Stock, Shares, Outstanding	11,390,189	8,347,427	8,031,307
Conversion of Stock, Shares Converted	398,262	288,620
Stock Issued During Period, Shares, New Issues	2,537,500	20,000
Common Stock, Shares, Issued	11,390,189	8,347,427
Common Class B [Member]
Class of Stock [Line Items]
Common Stock, Shares, Outstanding	719,200	1,117,462	1,406,082
Conversion of Stock, Shares Converted	(398,262)	(288,620)
Common Stock, Shares, Issued	719,200	1,117,462

Stockholders' Equity (Narrative

Stockholders' Equity (Narrative) (Details) - USD ($)	12 Months Ended
Stockholders' Equity (Narrative) (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2015
Class of Stock [Line Items]
Preferred Stock, Shares Authorized	20,000,000	20,000,000
Preferred Stock, Par Value Per Share	$ 1	$ 1
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%
Common Stock, Shares, Issued	12,109,389
Conversion of Stock, Shares Converted	398,262	288,620
Common Stock, Capital Shares Reserved for Future Issuance	374,478				1,200,000
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	53,900,000	$ 127,200,000
Preferred Stock, Cumulative Undeclared Dividend	$ 12,100,000	22,600,000
Operating Loss Carryforwards				$ 749,200,000
Common Stock Ownership Enabling Preferred Stock Purchase Rights	4.99%
Common Stock Ownership Enabling Preferred Stock Purchase Rights, Incremental	0.50%
Stock issued during period	$ 23,100,000
Payments for Repurchase of Preferred Stock and Preference Stock	$ 61,600,000	$ 0
Preferred Stock, Shares Outstanding	41,720	104,574	104,574
Common Class A [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized	70,000,000	70,000,000
Common Stock, Par or Stated Value Per Share	$ 0.10	$ 0.10
Common Stock, Shares, Issued	11,390,189	8,347,427
Stock Issued During Period, Shares, New Issues	2,537,500	20,000
Conversion of Stock, Shares Converted	398,262	288,620
Sale of Stock, Price Per Share	$ 10
Gross Proceeds from Issuance of Common Stock	$ 25,400,000
Payments of Stock Issuance Costs	$ 2,300,000
Common Class B [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized	30,000,000	30,000,000
Common Stock, Par or Stated Value Per Share	$ 0.10	$ 0.10
Common Stock, Shares, Issued	719,200	1,117,462
Conversion of Stock, Shares Converted	(398,262)	(288,620)
Preferred Series B [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	41,720	104,574
Preferred Stock, Liquidation Preference Per Share	$ 1,000
Preferred stock	$ 100,000	$ 4,600,000
Preferred Stock, Dividend Rate, Percentage	7.50%
Preferred Stock, Liquidation Preference, Value	$ 53,900,000	$ 127,200,000
Stock Repurchased and Retired During Period, Shares	62,854
Stock Repurchase Price per Share	$ 954.59
Payments for Repurchase of Preferred Stock and Preference Stock	60,000,000
Preferred Stock, Liquidation Amount per Share	$ 1,272.78
Preferred Stock, Shares Outstanding	41,720

Commitment and Contingencies (D

Commitment and Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Claim filed, unrecorded gain contingency,		$ 42.8
Scenario, Forecast [Member]
Litigation settlement, amount awarded from other party	$ 43.5

Revenue by Geographic Area (Det

Revenue by Geographic Area (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Revenue		$ 247.2	$ 209.7
United States
Revenue		171.7	152.4
Belgium
Revenue	$ 35.8		21.5
Japan
Revenue		23.4	23.4
Other Foreign
Revenue		16.3	12.4
Foreign [Member]
Revenue		$ 75.5	$ 57.3

Segment Information (Segment Re

Segment Information (Segment Reporting Information) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenue									$ 247.2	$ 209.7
Gross Profit	$ 35	$ (0.8)	$ 43.8	$ 19.6	$ 6.8	$ 35.5	$ (4.3)	$ (5.5)	97.6	32.5
Low Enriched Uranium Segment [Member]
Segment Reporting Information [Line Items]
Gross Profit									97.8	50.8
Technical Solutions Segment [Member]
Segment Reporting Information [Line Items]
Gross Profit									(0.2)	(18.3)
Separative Work Units [Member]
Segment Reporting Information [Line Items]
Revenue									151.5	123.7
Uranium [Member]
Segment Reporting Information [Line Items]
Revenue									39	45.7
Product [Member]
Segment Reporting Information [Line Items]
Revenue									190.5	169.4
Service [Member]
Segment Reporting Information [Line Items]
Revenue									$ 56.7	$ 40.3

Segment Information (Narrative)

Segment Information (Narrative) (Details)	12 Months Ended
Segment Information (Narrative) (Details)	Dec. 31, 2020	Dec. 31, 2019
Low Enriched Uranium Segment [Member]
Revenue from top 10 customers	7100.00%	7900.00%
Revenue from first customer over 10 percent	1400.00%	27.00%
Revenue from second customer over 10 percent	1300.00%	12.00%
Revenue from third customer over 10 percent	1000.00%	11.00%
Revenue from fourth customer over 10 percent		10.00%
Technical Solutions Segment [Member]
Revenue from first customer over 10 percent	2100.00%	1900.00%

Quarterly Results of Operatio_3

Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Revenue	$ 92.9	$ 33.6	$ 75.7	$ 45	$ 55.7	$ 104.7	$ 10.6	$ 38.7	$ 247.2	$ 209.7
Cost of sales	57.9	34.4	31.9	25.4	48.9	69.2	14.9	44.2	149.6	177.2
Gross profit (loss)	35	(0.8)	43.8	19.6	6.8	35.5	(4.3)	(5.5)	97.6	32.5
Advanced technology license and decommissioning costs	1	0.2	0.7	0.9	1.6	1.3	5.1	6.6	2.8	14.6
Selling, general and administrative	10.4	6.7	10.4	8.5	9.2	8.7	7.7	8.1	36	33.7
Amortization of intangible assets	2.5	1.2	1.7	1.4	2.4	1.8	1.2	1.1	6.8	6.5
Special charges for workforce reductions and advisory costs	0.1	0.6	0	(0.1)	0.3	0.8	(2.9)	(0.1)	0.6	(1.9)
Other (income)	0.4	0	0	0	0	(0.2)	(0.1)	(0.4)	0.4	(0.7)
Operating income (loss)	20.6	(9.5)	31	8.9	(6.7)	23.1	(15.3)	(20.8)	51	(19.7)
Nonoperating components of net periodic benefit expense (income)	5	(2.2)	(2.2)	(2.2)	(4.1)	(0.1)	0	(0.1)	(1.6)	(4.3)
Interest expense	0	0	0	0.1	0.1	0.9	1	1	0.1	3
Investment income	0	(0.1)	0	(0.4)	(0.3)	(0.5)	(0.7)	(0.7)	(0.5)	(2.2)
Provision (benefit) for income taxes	(0.8)	(0.2)	(0.5)	0.1	0.4	0	0	(0.1)	(1.4)	0.3
Net income (loss)	16.4	(7)	33.7	11.3	(2.8)	22.8	(15.6)	(20.9)	54.4	(16.5)
Preferred stock dividends, undeclared and cumulative	0.8	1.9	2	2	1.9	1.9	2	2	6.7	7.8
Preferred Stock Dividends and Other Adjustments	41.9	0	0	0					41.9	0
Net income (loss) allocable to common stockholders	$ (26.3)	$ (8.9)	$ 31.7	$ 9.3	$ (4.7)	$ 20.9	$ (17.6)	$ (22.9)	$ 5.8	$ (24.3)
Net income (loss) per common share - basic	$ (2.55)	$ (0.83)	$ 3.28	$ 0.97	$ (0.49)	$ 2.18	$ (1.84)	$ (2.40)	$ 0.59	$ (2.54)
Net income (loss) per common share - diluted	$ (2.55)	$ (0.83)	$ 3.19	$ 0.95	$ (0.49)	$ 2.17	$ (1.84)	$ (2.40)	$ 0.57	$ (2.54)