Reorganization and Restructuring Reorganization and Restructuring - Narrative (Details) $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Jan. 31, 2016 USD ($) director	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2017 USD ($) position	Dec. 31, 2016 USD ($) position	Dec. 31, 2015 USD ($) position	Dec. 31, 2014 USD ($)
Reorganization and Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Reorganization and restructuring costs		$ 18.1		$ 17.3
Cost savings				20.0
Restructuring Reserve [Roll Forward]
Beginning balance	$ 0.0			7.6	$ 0.0
Expense (benefit)				17.3	18.1
Payments and utilization				(23.1)	(10.5)
Foreign currency exchange effects				0.2
Ending balance		7.6	$ 0.0	$ 2.0	7.6	$ 0.0
Reorganization and Restructuring 2015
Restructuring Cost and Reserve [Line Items]
Reorganization and restructuring costs					$ 6.5	$ 11.6
Positions eliminated across the global workforce | position					1,100
Cost savings					$ 20.0
Cumulative pretax charges		18.0			18.0
Reorganization And Restructuring 2014
Restructuring Cost and Reserve [Line Items]
Positions eliminated across the global workforce | position						1,700
Cost savings						$ 50.0
Restructuring Reserve [Roll Forward]
Expense (benefit)						1.9	$ 21.8
Other Restructuring
Restructuring Cost and Reserve [Line Items]
Positions eliminated across the global workforce | position				300
Cost savings				$ 4.0
Estimated restructuring charges				1.0
Asset Related Adjustments | Reorganization and Restructuring 2016
Restructuring Reserve [Roll Forward]
Beginning balance	0.0			0.0	0.0
Expense (benefit)				4.1	16.3
Payments and utilization				(4.1)	(16.3)
Foreign currency exchange effects				0.0
Ending balance		0.0	0.0	0.0	0.0	0.0
Severance Costs | Reorganization and Restructuring 2016
Restructuring Reserve [Roll Forward]
Beginning balance	$ 0.0			7.0	0.0
Expense (benefit)				10.4	7.2
Payments and utilization				(16.0)	(0.2)
Foreign currency exchange effects				0.2
Ending balance		7.0	0.0	1.6	7.0	0.0
Severance Costs | Executive Leadership and Board of Directors Restructuring
Restructuring Cost and Reserve [Line Items]
Cumulative pretax charges		4.3			4.3
Severance Costs | Reorganization And Restructuring 2014
Restructuring Cost and Reserve [Line Items]
Cumulative pretax charges			24.0			24.0
Severance Costs | Other Restructuring
Restructuring Cost and Reserve [Line Items]
Reorganization and restructuring costs				4.6
Severance Costs | Director | Executive Leadership and Board of Directors Restructuring
Restructuring Cost and Reserve [Line Items]
Reorganization and restructuring costs			1.8
Positions eliminated across the global workforce | director	2
Lease Terminations
Restructuring Reserve [Roll Forward]
Expense (benefit)		0.7
Lease Terminations | Reorganization and Restructuring 2016
Restructuring Reserve [Roll Forward]
Beginning balance	$ 0.0			0.6	0.0
Expense (benefit)				0.6	0.7
Payments and utilization				(0.8)	(0.1)
Foreign currency exchange effects				0.0
Ending balance		0.6	0.0	0.4	0.6	0.0
Benefit Program Termination | Reorganization and Restructuring 2016
Restructuring Reserve [Roll Forward]
Beginning balance	$ 0.0			0.0	0.0
Expense (benefit)		(6.1)		2.2	(6.1)
Payments and utilization				(2.2)	6.1
Foreign currency exchange effects				0.0
Ending balance		$ 0.0	$ 0.0	$ 0.0	$ 0.0	$ 0.0
Minimum | Reorganization and Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Positions eliminated across the global workforce | position				800
Estimated restructuring charges				$ 10.0
Maximum | Reorganization and Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Positions eliminated across the global workforce | position				900
Estimated restructuring charges				$ 12.0