Restructuring, Impairment and Other - Schedule of Changes in the Restructuring and MEPP Reserves (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($)
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	$ 88.6
Restructuring and Other Charges	5.4
Foreign Exchange and Other	0.3
Cash Paid	(12.3)
Balance at the end	82.0
Employee terminations
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	6.2
Restructuring and Other Charges	1.5
Foreign Exchange and Other	0.1
Cash Paid	(2.6)
Balance at the end	5.2
Other
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	12.2
Restructuring and Other Charges	4.0
Foreign Exchange and Other	0.2
Cash Paid	(4.3)
Balance at the end	12.1
MEPP withdrawal obligations
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	70.2
Restructuring and Other Charges	(0.1)
Cash Paid	(5.4)
Balance at the end	$ 64.7