Restructuring (Restructuring Activity) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Reserve [Roll Forward]
Beginning balance	$ 23.7
Ending balance	3.0	$ 23.7
Asset-Related Costs
Restructuring Reserve [Roll Forward]
Net provisions		21.4	$ 17.7
November 2015 Restructuring Program
Restructuring Reserve [Roll Forward]
Beginning balance	19.2	4.5
Net provisions	33.0	65.8	8.6
Net benefits charged against the assets and other	(2.6)	(20.1)
Payments	(47.3)	(30.8)
Foreign currency translation	0.7	(0.2)
Ending balance	3.0	19.2	4.5
Total aggregate costs to date	107.4
November 2015 Restructuring Program | Employee Separation Costs
Restructuring Reserve [Roll Forward]
Beginning balance	5.9	1.3
Net provisions	2.7	10.5	2.2
Net benefits charged against the assets and other	0.0	0.0
Payments	(7.6)	(5.8)
Foreign currency translation	0.2	(0.1)
Ending balance	1.2	5.9	1.3
Total aggregate costs to date	15.4
November 2015 Restructuring Program | Asset-Related Costs
Restructuring Reserve [Roll Forward]
Beginning balance	0.0	0.0
Net provisions	2.4	19.4	1.9
Net benefits charged against the assets and other	(2.4)	(19.4)
Payments	0.0	0.0
Foreign currency translation	0.0	0.0
Ending balance	0.0	0.0	0.0
Total aggregate costs to date	23.7
November 2015 Restructuring Program | Other Costs
Restructuring Reserve [Roll Forward]
Beginning balance	13.3	3.2
Net provisions	27.9	35.9	4.5
Net benefits charged against the assets and other	(0.2)	(0.7)
Payments	(39.7)	(25.0)
Foreign currency translation	0.5	(0.1)
Ending balance	1.8	$ 13.3	$ 3.2
Total aggregate costs to date	$ 68.3