Restructuring - Accrued Liability for Restructuring Expense (Details) $ in Millions	6 Months Ended
	Jun. 30, 2017 USD ($)
Restructuring Reserve [Roll Forward]
Accrued liability as of January 1, 2017	$ 23.4
Charged to expense	17.3
Payments	(15.1)
Accrued liability as of June 30, 2017	25.6
Severance Benefits
Restructuring Reserve [Roll Forward]
Accrued liability as of January 1, 2017	21.5
Charged to expense	13.0
Payments	(10.3)
Accrued liability as of June 30, 2017	24.2
Other Costs
Restructuring Reserve [Roll Forward]
Accrued liability as of January 1, 2017	1.9
Charged to expense	4.3
Payments	(4.8)
Accrued liability as of June 30, 2017	$ 1.4