Consolidated Balance Sheet (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Statement of Financial Position [Abstract]
Allowance for accounts and notes receivable, current	$ 80	$ 98
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	100,000,000	100,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.75	$ 0.75
Common stock, shares authorized	6,000,000,000	6,000,000,000
Common stock, shares issued	2,442,676,580	2,442,676,580
Treasury stock, shares	495,978,691	461,509,656