Inventories (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Inventories [Line Items]
Raw materials	$ 1,693	$ 1,699
Work in process and other	855	883
Finished manufactured goods	3,266	3,187
Goods acquired for resale	3,859	3,906
Total inventory	$ 9,673	$ 9,675