Restructuring, Impairment and Other Charges - Schedule of Changes in the Restructuring Reserve (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	$ 52.5	$ 55.1
Restructuring and Other Charges	106.6	41.7
Foreign Exchange and Other	1.4	(1.7)
Cash Paid	(71.9)	(42.6)
Balance at the end	88.6	52.5
MEPP withdrawal obligations
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	40.5	44.2
Restructuring and Other Charges	40.0	2.9
Cash Paid	(10.3)	(6.6)
Balance at the end	70.2	40.5
Employee terminations
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	3.5	4.8
Restructuring and Other Charges	32.8	22.2
Foreign Exchange and Other		(1.7)
Cash Paid	(30.1)	(21.8)
Balance at the end	6.2	3.5
Other
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	8.5	6.1
Restructuring and Other Charges	33.8	16.6
Foreign Exchange and Other	1.4
Cash Paid	(31.5)	(14.2)
Balance at the end	$ 12.2	$ 8.5