Restructuring, Impairment and Other - Schedule of Changes in the Restructuring and MEPP Reserves (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2021 USD ($)
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	$ 88.6
Restructuring and Other Charges	15.5
Foreign Exchange and Other	0.3
Cash Paid	(34.9)
Balance at the end	69.5
Employee terminations
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	6.2
Restructuring and Other Charges	3.7
Foreign Exchange and Other	0.1
Cash Paid	(4.1)
Balance at the end	5.9
Other
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	12.2
Restructuring and Other Charges	11.6
Foreign Exchange and Other	0.2
Cash Paid	(9.2)
Balance at the end	14.8
MEPP withdrawal obligations
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	70.2
Restructuring and Other Charges	0.2
Cash Paid	(21.6)
Balance at the end	$ 48.8