Restructuring - Summary of Liabilities Recognized Related to Restructuring Plan (Detail) - 2019 Restructuring Plan [Member] $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2021 USD ($)
Restructuring Cost And Reserve [Line Items]
Expenses	$ 16.4	$ 50.7
Beginning Balance		64.7
Cash payments		(48.9)
Foreign currency exchange rate changes		(1.4)
Ending Balance	65.1	65.1
Expense incurred since the start of the 2019 Restructuring Plan	195.2	195.2
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	0.4	3.8
Beginning Balance		38.7
Cash payments		(11.7)
Foreign currency exchange rate changes		(1.2)
Ending Balance	29.6	29.6
Expense incurred since the start of the 2019 Restructuring Plan	82.3	82.3
Expense estimated to be recognized for the 2019 Restructuring Plan	180.0	180.0
Contract Termination [Member]
Restructuring Cost And Reserve [Line Items]
Expenses	5.5	12.3
Beginning Balance		10.9
Cash payments		(5.8)
Ending Balance	17.4	17.4
Expense incurred since the start of the 2019 Restructuring Plan	28.1	28.1
Expense estimated to be recognized for the 2019 Restructuring Plan	30.0	30.0
Other Restructuring [Member]
Restructuring Cost And Reserve [Line Items]
Expenses	10.5	34.6
Beginning Balance		15.1
Cash payments		(31.4)
Foreign currency exchange rate changes		(0.2)
Ending Balance	18.1	18.1
Expense incurred since the start of the 2019 Restructuring Plan	84.8	84.8
Expense estimated to be recognized for the 2019 Restructuring Plan	$ 165.0	$ 165.0