Restructuring, Impairment and Other Charges - Schedule of Changes in the Restructuring Reserve (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	$ 55.2	$ 60.4
Restructuring and Other Charges	41.8	31.7
Foreign Exchange and Other	(1.8)	0.9
Cash Paid	(42.6)	(37.8)
Balance at the end	52.6	55.2
Employee terminations
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	4.8	9.6
Restructuring and Other Charges	22.3	12.9
Foreign Exchange and Other	(1.8)	(1.5)
Cash Paid	(21.9)	(16.2)
Balance at the end	3.4	4.8
MEPP withdrawal obligations
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	44.2	47.9
Restructuring and Other Charges	2.9	2.9
Cash Paid	(6.5)	(6.6)
Balance at the end	40.6	44.2
MEPP withdrawal obligations and employee terminations
Restructuring Cost And Reserve [Line Items]
Balance at the beginning	6.2	2.9
Restructuring and Other Charges	16.6	15.9
Foreign Exchange and Other		2.4
Cash Paid	(14.2)	(15.0)
Balance at the end	$ 8.6	$ 6.2