Revenue Recognition and Contracts with Customers Revenue Recognition and Contracts with Customers (Policies)	3 Months Ended
Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue Recognition, Policy	Revenue Recognition 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 to the extent it is probable that a significant reversal of revenue recognized will not occur. Revenue for the Company’s LEU Segment is derived from sales of the separative work units (“SWU”) component of low enriched uranium (“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 fuel fabricators. Centrus ships LEU to nuclear fuel fabricators for scheduled or anticipated orders from utility customers. Based on customer orders, Centrus arranges for the transfer of title of LEU from Centrus to the customer for the specified quantity of LEU at the fuel fabricator. Revenue is recognized when control of LEU is transferred to the customer 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 physical receipt of LEU or uranium purchased from the Company beyond the contractual sale period. In such cases, title to LEU or uranium is 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 balance sheet and the customer-titled product is classified as Deferred Costs Associated with Deferred Revenue. Risk of loss remains with Centrus until physical delivery occurs. The recognition of revenue and related cost of sales occurs at the time physical delivery occurs and control and risk of loss of the product transfer to the customer, which may occur beyond one year. The timing of physical delivery, subject to notice period requirements, is at the option of the customer. As such, deferred costs and deferred revenue are classified within current assets and current liabilities, respectively. On occasion, Centrus will accept payment in the form of uranium. Revenue from the sale of SWU under such contracts is recognized at the time control of the LEU is transferred to the customer and is based on the fair value of the uranium transferred. 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. Revenue for the Contract Services Segment, principally representing engineering and testing activities performed by the Company, is recognized over the contractual period as services are rendered. The contract services segment consists primarily of revenue and cost of sales for engineering and testing work Centrus performs under an agreement with UT-Battelle, LLC (“UT-Battelle”), the management and operating contractor for Oak Ridge National Laboratory (“ORNL”). The contract services segment also includes limited services provided by Centrus to the U.S. Department of Energy (“DOE”) and its contractors at the Portsmouth site related to facilities the Company leases from DOE. In the three months ended March 31, 2018, revenue for the contract services segment included $9.5 million under a settlement agreement with DOE and the United States government. Refer below to Contract Balances for additional details. The Company recognizes revenue over time as it performs on these contracts because of the continuous transfer of control to the customer. 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 principally uses the cost-to-cost input method of progress for its contracts 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. 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 has applied the practical expedient in paragraph ASC 606 and does not provide 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 (contract assets) are included in Accounts Receivable 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 contract services revenue, the Company recognizes a liability included in Deferred Revenue and Advances from Customers on the consolidated balance sheet.

Revenue Recognition

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 to the extent it is probable that a significant reversal of revenue recognized will not occur.

Revenue for the Company’s LEU Segment is derived from sales of the separative work units (“SWU”) component of low enriched uranium (“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 fuel fabricators. Centrus ships LEU to nuclear fuel fabricators for scheduled or anticipated orders from utility customers. Based on customer orders, Centrus arranges for the transfer of title of LEU from Centrus to the customer for the specified quantity of LEU at the fuel fabricator. Revenue is recognized when control of LEU is transferred to the customer 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 physical receipt of LEU or uranium purchased from the Company beyond the contractual sale period. In such cases, title to LEU or uranium is 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 balance sheet and the customer-titled product is classified as Deferred Costs Associated with Deferred Revenue. Risk of loss remains with Centrus until physical delivery occurs. The recognition of revenue and related cost of sales occurs at the time physical delivery occurs and control and risk of loss of the product transfer to the customer, which may occur beyond one year. The timing of physical delivery, subject to notice period requirements, is at the option of the customer. As such, deferred costs and deferred revenue are classified within current assets and current liabilities, respectively.

On occasion, Centrus will accept payment in the form of uranium. Revenue from the sale of SWU under such contracts is recognized at the time control of the LEU is transferred to the customer and is based on the fair value of the uranium transferred.

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.

Revenue for the Contract Services Segment, principally representing engineering and testing activities performed by the Company, is recognized over the contractual period as services are rendered. The contract services segment consists primarily of revenue and cost of sales for engineering and testing work Centrus performs under an agreement with UT-Battelle, LLC (“UT-Battelle”), the management and operating contractor for Oak Ridge National Laboratory (“ORNL”). The contract services segment also includes limited services provided by Centrus to the U.S. Department of Energy (“DOE”) and its contractors at the Portsmouth site related to facilities the Company leases from DOE. In the three months ended March 31, 2018, revenue for the contract services segment included $9.5 million under a settlement agreement with DOE and the United States government. Refer below to Contract Balances for additional details.

The Company recognizes revenue over time as it performs on these contracts because of the continuous transfer of control to the customer. 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 principally uses the cost-to-cost input method of progress for its contracts 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. 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 has applied the practical expedient in paragraph ASC 606 and does not provide 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 (contract assets) are included in Accounts Receivable 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 contract services revenue, the Company recognizes a liability included in Deferred Revenue and Advances from Customers on the consolidated balance sheet.