Segment Information (Segment Reporting Information) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Revenues [Abstract]
Revenue, Contract Services	$ 6.4	$ 16.4
Total Revenue	7.2	90.0
Gross Profit	(2.5)	15.8
Low Enriched Uranium Segment [Member]
Revenues [Abstract]
Revenue, Goods	0.8	73.6
Gross Profit	(1.5)	8.1
Contract Services Segment [Member]
Revenues [Abstract]
Gross Profit	(1.0)	7.7
Separative Work Units [Member]
Revenues [Abstract]
Revenue, Goods	0.8	59.3
Uranium [Member]
Revenues [Abstract]
Revenue, Goods	$ 0.0	$ 14.3

Amount of revenue earned from products sold or services provided under the terms of a contract, including, but not limited to, government contracts and construction contracts, classified as other.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1,2)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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Aggregate revenue during the period from the sale of goods in the normal course of business, after deducting returns, allowances and discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(a))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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