Commitments and Contingencies, Environmental (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)
Environmental Contingency
Environmental accrual	$ 17.8	$ 17.8
Expected period related to remediation expenditures for environmental contingencies period		30 years
Potential increase in environmental costs	$ 24.7	$ 24.7
Time period within which Companys recorded estimate of its obligation may change	12 months
Maximum
Environmental Contingency
Period for final feasibility study		12 months