Restructuring Charges - Included in Cost of Revenues and Restructuring and Other Charges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges (benefits)	$ 35.3	$ 7.3	$ 65.6
Restructuring charges
Restructuring Cost and Reserve [Line Items]
Restructuring charges (benefits)	35.3	7.3	65.6
Severance
Restructuring Cost and Reserve [Line Items]
Restructuring charges (benefits)	21.5	8.3	57.7
Facility consolidations
Restructuring Cost and Reserve [Line Items]
Restructuring charges (benefits)	2.1	0.0	0.0
Contract terminations
Restructuring Cost and Reserve [Line Items]
Restructuring charges (benefits)	$ 11.7	$ (1.0)	$ 7.9