Segment Information - Revenue by Geographic Area (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Revenue	$ 35,475	$ 48,580	$ 45,266
Operating Segments
Segment Reporting Information [Line Items]
Revenue	35,475	48,580	45,266
Operating Segments | North America
Segment Reporting Information [Line Items]
Revenue	9,811	16,151	13,897
Operating Segments | Latin America
Segment Reporting Information [Line Items]
Revenue	6,014	7,699	7,754
Operating Segments | Europe/CIS/Africa
Segment Reporting Information [Line Items]
Revenue	9,284	12,515	12,411
Operating Segments | Middle East & Asia
Segment Reporting Information [Line Items]
Revenue	9,898	11,875	10,767
Eliminations & other
Segment Reporting Information [Line Items]
Revenue	$ 468	$ 340	$ 437