Segment Information - Revenue by Geographic Area (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Revenue	$ 8,504	$ 7,905	$ 24,636	$ 22,261
Operating Segments
Segment Reporting Information [Line Items]
Revenue	8,504	7,905	24,636	22,261
Operating Segments | North America
Segment Reporting Information [Line Items]
Revenue	3,189	2,602	9,164	6,675
Operating Segments | Latin America
Segment Reporting Information [Line Items]
Revenue	978	952	2,767	2,942
Operating Segments | Europe/CIS/Africa
Segment Reporting Information [Line Items]
Revenue	1,820	1,843	5,316	5,255
Operating Segments | Middle East & Asia
Segment Reporting Information [Line Items]
Revenue	2,417	2,352	7,079	7,007
Eliminations & other
Segment Reporting Information [Line Items]
Revenue	$ 100	$ 156	$ 310	$ 382