BUSINESS SEGMENT INFORMATION - Business Segment Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011		Dec. 31, 2011
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	$ 4,141		$ 4,282		$ 12,554		$ 12,515
Other Income (Expense):
General and administrative	(124)		(112)		(384)		(327)
Merger, acquisitions & transition	(7)		(4)		(29)		(15)
Financing costs, net	(40)		(37)		(125)		(123)
Income Before Income Taxes	865		2,094		3,236		6,152
Oil and Gas Production Revenues	4,141		4,282		12,554		12,515
Total Assets	58,810				58,810				52,051
UNITED STATES
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	1,533		1,548		4,525		4,485
Other Income (Expense):
Operating Income (Loss)	495	[1]	718	[1]	1,692	[1]	2,086	[1]
Oil and Gas Production Revenues	1,533		1,548		4,525		4,485
Total Assets	29,786		23,039		29,786		23,039
CANADA
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	318		388		966		1,223
Other Income (Expense):
Operating Income (Loss)	(744)	[1]	81	[1]	(1,903)	[1]	264	[1]
Oil and Gas Production Revenues	318		388		966		1,223
Total Assets	7,349		8,443		7,349		8,443
EGYPT
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	1,143		1,214		3,403		3,615
Other Income (Expense):
Operating Income (Loss)	781	[1]	893	[1]	2,380	[1]	2,679	[1]
Oil and Gas Production Revenues	1,143		1,214		3,403		3,615
Total Assets	7,208		6,574		7,208		6,574
AUSTRALIA
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	397		461		1,211		1,303
Other Income (Expense):
Operating Income (Loss)	231	[1]	288	[1]	683	[1]	823	[1]
Oil and Gas Production Revenues	397		461		1,211		1,303
Total Assets	5,876		4,446		5,876		4,446
North Sea [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	624		547		2,060		1,549
Other Income (Expense):
Operating Income (Loss)	236	[1]	222	[1]	752	[1]	685	[1]
Oil and Gas Production Revenues	624		547		2,060		1,549
Total Assets	6,581		3,166		6,581		3,166
ARGENTINA
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	126		124		389		340
Other Income (Expense):
Operating Income (Loss)	6	[1]	19	[1]	51	[1]	50	[1]
Oil and Gas Production Revenues	126		124		389		340
Total Assets	1,823		1,732		1,823		1,732
Other International [Member]
Other Income (Expense):
Operating Income (Loss)	(7)	[1]	(20)	[1]	(14)	[1]	(46)	[1]
Total Assets	187		82		187		82
Foreign Tax Authority [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	4,141		4,282		12,554		12,515
Other Income (Expense):
Operating Income (Loss)	998	[1]	2,201	[1]	3,641	[1]	6,541	[1]
Other	38		46		133		76
General and administrative	(124)		(112)		(384)		(327)
Merger, acquisitions & transition	(7)		(4)		(29)		(15)
Financing costs, net	(40)		(37)		(125)		(123)
Income Before Income Taxes	865		2,094		3,236		6,152
Oil and Gas Production Revenues	4,141		4,282		12,554		12,515
Total Assets	$ 58,810		$ 47,482		$ 58,810		$ 47,482

[1] Operating Income (Loss) consists of oil and gas production revenues less depreciation, depletion and amortization, asset retirement obligation accretion, lease operating expenses, gathering and transportation costs, and taxes other than income. Canada's operating loss for the three and nine months ended September 30, 2012, includes additional depletion of $721 million and $1.9 billion, respectively, to write-down the carrying value of oil and gas properties.