Restructuring Charges - Roll-forward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Reserve [Roll Forward]
Charges/ (Benefits)	$ 68.0	$ 35.3	$ 7.3
2019 Restructuring Plan
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance	0.7
Charges/ (Benefits)	68.0
Cash Payments	(12.3)
Other	(5.7)
Restructuring liability, ending balance	50.7	0.7
2019 Restructuring Plan | Severance
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance	0.7
Charges/ (Benefits)	62.8
Cash Payments	(12.3)
Other	(0.5)
Restructuring liability, ending balance	50.7	0.7
2019 Restructuring Plan | Facility consolidations and other
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance	0.0
Charges/ (Benefits)	5.2
Cash Payments	0.0
Other	(5.2)
Restructuring liability, ending balance	$ 0.0	$ 0.0