Property, Plant and Equipment (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Total property, plant and equipment	$ 37,049	$ 52,027
Less accumulated depreciation, depletion and amortization	16,731	19,805
Property, plant and equipment, net	20,318	32,222
United States Exploration and Production [Member]
Segment Reporting Information [Line Items]
Total property, plant and equipment	14,549	13,532
International Exploration and Production [Member]
Segment Reporting Information [Line Items]
Total property, plant and equipment	12,270	11,736
Exploration and Production Segment [Member]
Segment Reporting Information [Line Items]
Total property, plant and equipment	26,819	25,268
Oil Sands Mining Segment [Member]
Segment Reporting Information [Line Items]
Total property, plant and equipment	9,866	9,631
Integrated Gas Segment [Member]
Segment Reporting Information [Line Items]
Total property, plant and equipment	36	47
Refining, Marketing and Transportation Segment [Member]
Segment Reporting Information [Line Items]
Total property, plant and equipment	0	16,624
Corporate [Member]
Segment Reporting Information [Line Items]
Total property, plant and equipment	328	457
Libya [Member]
Segment Reporting Information [Line Items]
Property, plant and equipment, net	758
Blocked international payments	$ 200
Proved Developed and Undeveloped Reserves, Net		242,000,000