Restructuring Activities - Summary of Changes in Liabilities for Restructuring Activities (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Restructuring And Related Activities [Abstract]
Beginning Balance		$ 68
Reclassification of ASC 420 real estate restructuring to right-of -use asset	[1]	(22)
Charges		35	$ 24
Payments		(21)
Effect of foreign currency translation and other adjustments		(3)
Ending Balance		$ 57

[1] Upon adoption of ASC 842, the real estate operating lease ASC 420 liabilities were reclassified and presented as a reduction of the related operating lease right of-use-asset.