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Inventories (Narrative) (Details) (USD $) In Millions, unless otherwise specified | 12 Months Ended |
--- | --- | ---
Dec. 31, 2011 | Dec. 31, 2010
Inventories |  |
Inventories provided by customers and suppliers | $ 2.9 | $ 3.3
Decline in Uranium Spot Price Indicator | 17.00% |
Decline in Uranium Quantities Provided by Customers and Suppliers | 6.00% |

X
- Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition Decline in Uranium Quantities Provided by Customers and Suppliers + References No definition available. + Details
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Namespace Prefix: | usu_
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- Definition Decline in Uranium Spot Price Indicator + References No definition available. + Details
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Namespace Prefix: | usu_
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Balance Type: | na
Period Type: | duration

X
- Definition Uranium held by USEC to which title was held by customers and suppliers and for which no assets or liabilities were recorded on the balance sheet + References No definition available. + Details
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