Capitalized Exploratory Well Costs (Tables)

12 Months Ended

Dec. 31, 2011

Capitalized Exploratory Well Costs [Abstract]

Changes in Capitalized Exploratory Well Costs

Changes in capitalized exploratory well costs are as follows and exclude amounts that were capitalized and subsequently expensed in the same period:

	Year Ended December 31,
	2011			2010			2009
(millions)
Capitalized Exploratory Well Costs, Beginning of Period	$	466		$	463		$	522
Additions to Capitalized Exploratory Well Costs Pending Determination of Proved Reserves		322			161			153
Reclassified to Proved Oil and Gas Properties Based on Determination of Proved Reserves		(55	)		(155	)		(205	)
Capitalized Exploratory Well Costs Charged to Expense		(37	)		(3	)		(7	)
Capitalized Exploratory Well Costs, End of Period	$	696		$	466		$	463

Aging of Capitalized Well Costs

The following table provides an aging of capitalized exploratory well costs (suspended well costs) based on the date that drilling commenced and the number of projects for which exploratory well costs have been capitalized for a period greater than one year since the commencement of drilling:

	December 31,
	2011		2010		2009
(millions)
Exploratory Well Costs Capitalized for a Period of One Year or Less	$	318	$	166	$	175
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling		378		300		288
Balance at End of Period	$	696	$	466	$	463
Number of Projects with Exploratory Well Costs That Have Been Capitalized for a Period Greater Than One Year Since Commencement of Drilling		9		9		5

Aging of Exploratory Well Costs

The following table provides a further aging of those exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling as of December 31, 2011:

			Suspended Since
	Total		2010		2009		2008 & Prior
(millions)
Country/Project
Offshore Equatorial Guinea
Blocks O and I	$	112	$	6	$	19	$	87
Offshore Cameroon
YoYo		40		2		2		36
Offshore Israel
Leviathan		41		41		-		-
Dalit		22		1		21		-
Deepwater Gulf of Mexico
Gunflint		59		3		6		50
Deep Blue		73		54		19		-
North Sea
Selkirk		23		1		1		21
Other
2 projects of $10 million or less each		8		8		-		-
Total	$	378	$	116	$	68	$	194