Consolidated Balance Sheets Parentheticals (unaudited) (USD $) In Millions, except Share data	Sep. 30, 2011	Dec. 31, 2010
Consolidated Balance Sheets Parenthetical [Abstract]
Allowance for doubtful accounts	$ 2	$ 7
Less accumulated depreciation, depletion and amortization	$ 16,731	$ 19,805
Preferred stock, no par value	$ 0	$ 0
Preferred stock shares authorized	26,000,000	26,000,000
Preferred stock shares issued	0	0
Preferred stock shares outstanding	0	0
Common stock, par value per share	$ 1	$ 1
Common stock shares authorized	1,100,000,000	1,100,000,000
Common stock, shares issued	770,000,000	770,000,000
Common stock, securities exchangeable, no par value	$ 0	$ 0
Common stock, securities exchangeable, shares authorized	29,000,000	29,000,000
Common stock, securities exchangeable, shares issued	0	0
Common stock, securities exchangeable, shares outstanding	0	0
Held in treasury, shares	66,000,000	60,000,000