Commitments and Contingencies, Environmental (Details) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)
Environmental Contingency
Environmental accrual	$ 17.2	$ 17.2
Expected period related to remediation expenditures for environmental contingencies period		30 years
Potential increase in environmental costs	$ 11.6	$ 11.6
Time period within which Companys recorded estimate of its obligation may change	12 months
Minimum
Environmental Contingency
Period for final feasibility study		12 months
Maximum
Environmental Contingency
Period for final feasibility study		18 months

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Period For Final Feasibility Study

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Total costs accrued as of the balance sheet date for environmental loss contingencies.

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The difference between the maximum amount of estimated loss and the amount recorded as of the balance sheet date.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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