Restructuring and Asset Impairments - Rollforward of all restructuring activities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Rollforward of all restructuring activities
Restructuring reserve balance, at the beginning of the period	$ 8.2
Restructuring expense	27.2	$ 23.4	$ 9.4
Use of Reserve	28.8
Reserve Reclassifications	1.0
Restructuring reserve balance, at the end of the period	$ 5.6	$ 8.2