Commitments and Contingencies, Textuals (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014
Environmental Contingency
Environmental accrual	$ 22.2
Expected period related to remediation expenditures for environmental contingencies period	30 years
Potential increase in environmental costs	$ 24.9
Minimum
Environmental Contingency
Period for final feasibility study	18 months
Maximum
Environmental Contingency
Period for final feasibility study	24 months