Industry Segments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 segment	Jun. 30, 2013
Industry Segments
Number of operating segments			3
Segment Information
Net sales	$ 6,275	$ 5,962	$ 12,363	$ 11,834
Pre-tax operating profit (loss)	2,392	2,228	4,713	4,431
Income taxes	(957)	(901)	(1,889)	(1,745)
Discontinued operations, net	(1)	(5)	2	(9)
Net income attributable to noncontrolling interest	(3)		(5)
Net income (loss) attributable to common stock	1,431	1,322	2,821	2,677
Pre-tax gain on sale of property			535
Impairment charges, before tax	471		471
Gain on sale of equity investment			131
Charge for former employees and consultants		55		55
Operating segments | Oil and Gas
Segment Information
Net sales	4,807	4,721	9,483	9,161
Pre-tax operating profit (loss)	2,182	2,100	4,286	4,020
Net income (loss) attributable to common stock	2,182	2,100	4,286	4,020
Operating segments | Chemical
Segment Information
Net sales	1,242	1,187	2,462	2,362
Pre-tax operating profit (loss)	133	275	269	434
Net income (loss) attributable to common stock	133	275	269	434
Operating segments | Midstream and Marketing
Segment Information
Net sales	530	269	965	722
Pre-tax operating profit (loss)	222	48	394	263
Net income attributable to noncontrolling interest	(3)		(5)
Net income (loss) attributable to common stock	219	48	389	263
Corporate and Eliminations
Segment Information
Net sales	(304)	(215)	(547)	(411)
Pre-tax operating profit (loss)	(145)	(195)	(236)	(286)
Income taxes	(957)	(901)	(1,889)	(1,745)
Discontinued operations, net	(1)	(5)	2	(9)
Net income (loss) attributable to common stock	$ (1,103)	$ (1,101)	$ (2,123)	$ (2,040)