Inventories (Schedule of Inventories) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Inventory, Net [Abstract]
Separative work units inventory	$ 14.8	$ 17.0
Uranium inventory	68.7	47.8
Inventories	83.5	64.8
Separative work units owed to customers and suppliers	0.1	4.6
Uranium owed to customers and suppliers	13.2	0.3
Inventories owed to customers and suppliers	13.3	4.9
Separative work units net of liability	14.7	12.4
Uranium inventory net of liability	55.5	47.5
Inventories, net	$ 70.2	$ 59.9

Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118951113&loc=d3e6676-107765

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 330
-SubTopic 10
-Section 35
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=116846819&loc=d3e3927-108312

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.6(a))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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