Industry Segments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 segment	Sep. 30, 2013
Industry Segments
Number of operating segments			3
Segment Information
Net sales	$ 5,996	$ 6,449	$ 18,359	$ 18,283
Pre-tax operating profit (loss)	2,031	2,625	6,744	7,056
Income taxes	(817)	(1,037)	(2,706)	(2,782)
Discontinued operations, net	(3)	(5)	(1)	(14)
Net income attributable to noncontrolling interest	(3)		(8)
Net income (loss) attributable to common stock	1,208	1,583	4,029	4,260
Pre-tax gain on sale of property			532
Impairment charges, before tax			471
Gain on sale of equity investment				131
Charge for former employees and consultants				55
Operating segments | Oil and Gas
Segment Information
Net sales	4,652	5,018	14,135	14,179
Pre-tax operating profit (loss)	1,899	2,363	6,185	6,383
Net income (loss) attributable to common stock	1,899	2,363	6,185	6,383
Operating segments | Chemical
Segment Information
Net sales	1,232	1,200	3,694	3,562
Pre-tax operating profit (loss)	140	181	409	615
Net income (loss) attributable to common stock	140	181	409	615
Operating segments | Midstream and Marketing
Segment Information
Net sales	362	442	1,327	1,164
Pre-tax operating profit (loss)	128	212	522	475
Net income attributable to noncontrolling interest	(3)		(8)
Net income (loss) attributable to common stock	125	212	514	475
Corporate and Eliminations
Segment Information
Net sales	(250)	(211)	(797)	(622)
Pre-tax operating profit (loss)	(136)	(131)	(372)	(417)
Income taxes	(817)	(1,037)	(2,706)	(2,782)
Discontinued operations, net	(3)	(5)	(1)	(14)
Net income (loss) attributable to common stock	$ (956)	$ (1,173)	$ (3,079)	$ (3,213)