Environmental Obligations Environmental Reserve Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accrual for Environmental Loss Contingencies [Roll Forward]
Total environmental reserves, net of recoveries beginning of period	$ 366.7	$ 340.9	$ 284.3
Provision	106.0	81.0	66.9
Spending, net of recoveries	(63.6)	(52.6)	(57.0)
Transfer from environmental obligations	2.6		47.2
Foreign currency translation adjustments	6.5	(2.6)	(0.5)
Net Change	51.5	25.8	56.6
Total environmental reserves, net of recoveries end of period	$ 418.2	$ 366.7	$ 340.9