Restructuring - Summary of Liabilities Recognized Related to Restructuring Plan (Detail) - 2019 Restructuring Plan [Member] $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)
Restructuring Cost And Reserve [Line Items]
Expenses	$ 15.3	$ 34.3
Beginning Balance		64.7
Cash payments		(29.8)
Foreign currency exchange rate changes		(0.7)
Ending Balance	68.5	68.5
Expense incurred since the start of the 2019 Restructuring Plan	178.8	178.8
Expense estimated to be recognized for the 2019 Restructuring Plan	375.0	375.0
Employee Termination Benefits [Member]
Restructuring Cost And Reserve [Line Items]
Expenses	1.8	3.4
Beginning Balance		38.7
Cash payments		(8.5)
Foreign currency exchange rate changes		(0.7)
Ending Balance	32.9	32.9
Expense incurred since the start of the 2019 Restructuring Plan	81.9	81.9
Expense estimated to be recognized for the 2019 Restructuring Plan	180.0	180.0
Contract Termination [Member]
Restructuring Cost And Reserve [Line Items]
Expenses	1.5	6.8
Beginning Balance		10.9
Cash payments		(3.6)
Ending Balance	14.1	14.1
Expense incurred since the start of the 2019 Restructuring Plan	22.6	22.6
Expense estimated to be recognized for the 2019 Restructuring Plan	25.0	25.0
Other Restructuring [Member]
Restructuring Cost And Reserve [Line Items]
Expenses	12.0	24.1
Beginning Balance		15.1
Cash payments		(17.7)
Ending Balance	21.5	21.5
Expense incurred since the start of the 2019 Restructuring Plan	74.3	74.3
Expense estimated to be recognized for the 2019 Restructuring Plan	$ 170.0	$ 170.0