Restructuring Charges - Changes to Restructuring Liabilities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Restructuring Reserve [Roll Forward]
Charges	$ (1.1)	$ 4.4	$ 35.6	$ 2.3
2019 Restructuring Plan
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance			1.1
Charges			35.6
Cash Payments			(31.7)
Other			(2.2)
Restructuring liability, ending balance	2.8		2.8
2019 Restructuring Plan | Severance
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance			1.1
Charges	(0.3)		21.8
Cash Payments			(20.7)
Other			0.0
Restructuring liability, ending balance	2.2		2.2
2019 Restructuring Plan | Facility consolidations
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance			0.0
Charges			2.1
Cash Payments			(0.1)
Other			(2.0)
Restructuring liability, ending balance	0.0		0.0
2019 Restructuring Plan | Contract terminations
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance			0.0
Charges	(0.8)		11.7
Cash Payments			(10.9)
Other			(0.2)
Restructuring liability, ending balance	$ 0.6		$ 0.6