Restructuring Charges - Included in Cost of Revenues and Restructuring and Other Charges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring charges (benefits)	$ 68.0	$ 35.3	$ 7.3
Restructuring charges
Restructuring Cost and Reserve [Line Items]
Restructuring charges (benefits)	68.0	35.3	7.3
Severance
Restructuring Cost and Reserve [Line Items]
Restructuring charges (benefits)	62.8	21.5	8.3
Contract terminations
Restructuring Cost and Reserve [Line Items]
Restructuring charges (benefits)	0.0	11.7	(1.0)
Facility consolidations and other
Restructuring Cost and Reserve [Line Items]
Restructuring charges (benefits)	$ 5.2	$ 2.1	$ 0.0