Commitments and Contingencies, Environmental (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)
Environmental Contingency
Environmental accrual	$ 18.1
Expected period related to remediation expenditures for environmental contingencies period	30 years
Potential increase in environmental costs	$ 24.7
Time period within which Companys recorded estimate of its obligation may change	12 months
Minimum
Environmental Contingency
Period for final feasibility study	9 months
Maximum
Environmental Contingency
Period for final feasibility study	15 months