Capitalized Exploratory Well Costs (Tables)

9 Months Ended

Sep. 30, 2012

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: 

	Nine Months Ended September 30, 2012
(millions)
Capitalized Exploratory Well Costs, Beginning of Period	$	696
Additions to Capitalized Exploratory Well Costs Pending Determination of Proved Reserves	164
Reclassified to Proved Oil and Gas Properties Based on Determination of Proved Reserves	(27		)
Capitalized Exploratory Well Costs Charged to Expense (1)	(108		)
Other (2)	(19		)
Capitalized Exploratory Well Costs, End of Period	$	706

 ⁽¹⁾ Amount primarily represents the Deep Blue exploratory well (deepwater Gulf of Mexico) costs capitalized prior to December 31, 2011. Although hydrocarbons were found in both the initial exploration well and subsequent sidetrack, we and our partners decided not to proceed with additional appraisal activities.

⁽²⁾ Amount represents the Selkirk exploratory well (North Sea) which, along with our other North Sea assets, was reclassified to held for sale at June 30, 2012. See Note 3. Acquisitions and Divestitures.

Aging of Capitalized Well Costs

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

	September 30, 2012		December 31, 2011
(millions)
Exploratory Well Costs Capitalized for a Period of One Year or Less	$	301	$	318
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling	405		378
Balance at End of Period	$	706	$	696
Number of Projects with Exploratory Well Costs That Have Been Capitalized for a Period Greater Than One Year Since Commencement of Drilling	9		9

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 September 30, 2012:

			Suspended Since
	Total		2011		2010		2009 & Prior
(millions)
Country/Project:
Offshore Equatorial Guinea
Blocks O and I	$	156	$	44	$	6	$	106
Offshore Cameroon
YoYo	45		5		2		38
Offshore Israel
Leviathan	78		37		41		—
Leviathan-1 Deep	28		28		—		—
Dalit	22		—		1		21
Offshore Cyprus
Cyprus A-1	10		10		—		—
Deepwater Gulf of Mexico
Gunflint	54		—		—		54
Other
2 projects of $10 million or less each	12		6		6		—
Total	$	405	$	130	$	56	$	219