Industry Segments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011 Y segment	Sep. 30, 2010
Industry Segments
Number of reportable segments			3
Segment Information
Net sales	$ 6,006	$ 4,763	$ 17,905	$ 13,982
Pretax operating profit (loss)			8,251	5,812
Income taxes	(1,087)	(822)	(3,252)	(2,377)
Discontinued operations, net	(4)	(12)	138	(59)
Less: Net income attributable to noncontrolling interest		(22)		(58)
Net income (loss) attributable to common stock	1,771	1,191	5,137	3,318
Charges on debt extinguishment			163
Oil and Gas
Segment Information
Net sales			13,635	10,517
Pretax operating profit (loss)			7,704	5,543
Less: Net income attributable to noncontrolling interest				(58)
Net income (loss) attributable to common stock			7,704	5,485
Chemical
Segment Information
Net sales			3,721	3,020
Pretax operating profit (loss)			717	327
Net income (loss) attributable to common stock			717	327
Midstream, Marketing and Other
Segment Information
Net sales			1,109	993
Pretax operating profit (loss)			378	270
Net income (loss) attributable to common stock			378	270
Corporate and Eliminations
Segment Information
Net sales			(560)	(548)
Pretax operating profit (loss)			(548)	(328)
Income taxes			(3,252)	(2,377)
Discontinued operations, net			138	(59)
Net income (loss) attributable to common stock			$ (3,662)	$ (2,764)