Segment and Geographic Area Information - Schedule of Segment Reporting Information to Consolidated Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule Of Assets By Segment [Line Items]
Consolidated assets	$ 36,528	$ 37,363
Cash and cash equivalents	1,919	1,877	$ 1,437	$ 1,861
Corporate goodwill	5,401	5,247	$ 3,415
Corporate fixed assets, net	14,815	16,426
LIFO reserve	(559)	(767)
Operating Segments [Member]
Schedule Of Assets By Segment [Line Items]
Consolidated assets	29,666	31,341
Intersegment Eliminations [Member]
Schedule Of Assets By Segment [Line Items]
Consolidated assets	(318)	(490)
Other [Member]
Schedule Of Assets By Segment [Line Items]
Cash and cash equivalents	1,919	1,877
Deferred income taxes	2,668	3,139
Corporate goodwill	476	485
Corporate fixed assets, net	733	819
LIFO reserve	(559)	(767)
Fair value of derivative contracts	1,078	16
Other	$ 865	$ 943