Summary of Components of Interest as Presented in Consolidated Statements of Operations (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Debt Instrument [Line Items]
Income	$ 3.2	$ 4.1
Expense on borrowings	(51.3)	(44.7)
Income (expense) on UTPs and other tax related liabilities	1.8	(2.1)
Capitalized	0.3	0.3
Net periodic pension costs - interest component	(4.7)	(5.0)
Total	$ (50.7)	$ (47.4)