Restructuring - Summary of Restructuring Activities (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Reserve [Roll Forward]
Accrual as of beginning of period		$ 157.7	$ 108.7	$ 98.0
Charges	$ 8.1	132.0	194.2	88.0
Utilization, Cash		(127.4)	(135.7)	(72.6)
Utilization, Non-cash		(23.3)	(9.5)	(4.7)
Accrual as of end of period	139.0	139.0	157.7	108.7
Employee termination benefits
Restructuring Reserve [Roll Forward]
Accrual as of beginning of period		152.8	103.3	93.0
Charges		104.2	167.8	74.5
Utilization, Cash		(122.2)	(118.3)	(64.2)
Utilization, Non-cash		0.0	0.0	0.0
Accrual as of end of period	134.8	134.8	152.8	103.3
Asset impairments
Restructuring Reserve [Roll Forward]
Accrual as of beginning of period		0.0	0.0	0.0
Charges		23.3	9.5	4.7
Utilization, Cash		0.0	0.0	0.0
Utilization, Non-cash		(23.3)	(9.5)	(4.7)
Accrual as of end of period	0.0	0.0	0.0	0.0
Contract termination costs
Restructuring Reserve [Roll Forward]
Accrual as of beginning of period		4.9	5.4	5.0
Charges		2.0	3.0	1.5
Utilization, Cash		(2.7)	(3.5)	(1.1)
Utilization, Non-cash		0.0	0.0	0.0
Accrual as of end of period	4.2	4.2	4.9	5.4
Other related costs
Restructuring Reserve [Roll Forward]
Accrual as of beginning of period		0.0	0.0	0.0
Charges		2.5	13.9	7.3
Utilization, Cash		(2.5)	(13.9)	(7.3)
Utilization, Non-cash		0.0	0.0	0.0
Accrual as of end of period	$ 0.0	$ 0.0	$ 0.0	$ 0.0