Inventories (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Raw materials	$ 3,094	$ 2,997
Work in process and other	2,228	2,315
Finished manufactured goods	4,188	4,179
Goods acquired for resale	6,734	6,696
Total inventory	$ 16,244	$ 16,187