Summary of Information about Contract Balance with Customers (Detail) - USD ($) $ in Millions		Mar. 31, 2018	Dec. 31, 2017
Contract With Customer Asset And Liability [Abstract]
Receivables, net		$ 2,406.0	$ 2,157.2
Contract assets	[1]	25.7
Contract liabilities	[2]	$ 33.6	$ 33.0

[1] Included in other current assets.

[2] Included in other current and other non-current liabilities.