Inventories (Detail) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Raw materials	$ 1,838	$ 1,881
Work in process and other	856	850
Finished manufactured goods	3,503	3,333
Goods acquired for resale	5,798	4,172
Total inventory	$ 11,995	$ 10,236