Restructuring, Impairment and Other - Schedule of Changes in the Restructuring and MEPP Reserves (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($)
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	$ 88.6
Restructuring and Other Charges	23.3
Cash Paid	(42.4)
Balance at the end	69.5
Employee terminations
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	6.2
Restructuring and Other Charges	6.3
Foreign Exchange and Other	0.1
Cash Paid	(6.2)
Balance at the end	6.4
Other
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	12.2
Restructuring and Other Charges	16.1
Foreign Exchange and Other	(0.1)
Cash Paid	(13.0)
Balance at the end	15.2
MEPP withdrawal obligations
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	70.2
Restructuring and Other Charges	0.9
Cash Paid	(23.2)
Balance at the end	$ 47.9