Summary of Changes in Contract Assets and Contract Liabilities (Detail) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
		Sep. 30, 2018	Sep. 30, 2018
Contract assets
Beginning balance		$ 18.7	$ 0.0
Increases/(decreases) due to cumulative catch up adjustment		0.0	15.0
Increases/(decreases) due to revenue recognized		19.3	56.1
Increases/(decreases) due to cash received		0.0	0.0
Increases/(decreases) due to transfer to receivables		(18.7)	(51.8)
Translation difference		0.0	0.0
Ending balance	[1]	19.3	19.3
Contract liabilities
Beginning balance		30.3	33.0	[2]
Increases/(decreases) due to revenue recognized		(1.5)	(3.9)
Translation difference		2.8	2.5
Ending balance	[2]	$ 31.6	$ 31.6

[1] Included in other current assets.

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