Inventories (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Inventory, Net [Abstract]
Finished products	$ 3,857	$ 4,449
Semifinished products	2,443	2,407
Raw materials, stores and supplies	1,323	1,313
Total inventories before LIFO adjustment	7,623	8,169
Adjustment of inventories to a last-in, first-out (LIFO) basis	(592)	(604)
Total	$ 7,031	$ 7,565