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Environmental Compliance (Narrative) (Details) (USD $) In Millions, unless otherwise specified | Dec. 31, 2011 | Dec. 31, 2010
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Environmental Compliance |  |
Depleted uranium disposition | $ 145.2 | $ 125.4
Financial assurance amount | 233.1 |
Accrued liabilities for stored wastes | 2.1 | 2.0
Accrued liabilities for lease turnover costs | $ 42.6 | $ 41.2

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