Summary of Activity Relating to Securitization Arrangement (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Sold receivables at beginning of period	$ 71	$ 68
Proceeds from sales of receivables	62	62
Cash collections (remitted to the owners of the receivables)	(71)	(71)
Effect of currency exchange rate changes	2	2
Sold receivables at end of period	$ 64	$ 61