Industry Segments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012 segment	Mar. 31, 2011
Industry Segments
Number of reportable segments	3
Segment Information
Net sales	$ 6,268	$ 5,726
Pretax operating profit (loss)	2,699	2,459
Income taxes	(1,139)	(1,054)
Discontinued operations, net	(1)	144
Net income (loss)	1,559	1,549
Charges on debt extinguishment		163
Oil and Gas
Segment Information
Net sales	4,902	4,367
Pretax operating profit (loss)	2,504	2,468
Net income (loss)	2,504	2,468
Chemical
Segment Information
Net sales	1,148	1,165
Pretax operating profit (loss)	184	219
Net income (loss)	184	219
Midstream, Marketing and Other
Segment Information
Net sales	393	412
Pretax operating profit (loss)	131	114
Net income (loss)	131	114
Corporate and Eliminations
Segment Information
Net sales	(175)	(218)
Pretax operating profit (loss)	(120)	(342)
Income taxes	(1,139)	(1,054)
Discontinued operations, net	(1)	144
Net income (loss)	$ (1,260)	$ (1,252)