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Commitments and Contingencies, Environmental (Details) $ in Millions | 3 Months Ended
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Mar. 31, 2019 USD ($)
Environmental Contingency |
Environmental accrual | $ 17.1
Expected period related to remediation expenditures for environmental contingencies period | 30 years
Potential increase in environmental costs | $ 11.6
Time period within which Companys recorded estimate of its obligation may change | 12 months
Minimum [Member] |
Environmental Contingency |
Period for final feasibility study | 9 months

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