Accounting for Suspended Exploratory Wells (Tables)

12 Months Ended

Dec. 31, 2011

Accounting for Suspended Exploratory Wells [Abstract]

Changes in company's suspended exploratory well costs

	2011			2010			2009
Beginning balance at January 1	$	2,718		$	2,435		$	2,118
Additions to capitalized exploratory well costs pending the determination of proved reserves		652			482			663
Reclassifications to wells, facilities and equipment based on the determination of proved reserves		(828	)		(129	)		(174	)
Capitalized exploratory well costs charged to expense		(45	)		(70	)		(172	)
Other reductions*		(63	)		–			–
Ending balance at December 31	$	2,434		$	2,718		$	2,435

* Represents property sales.

Aging of capitalized well costs and number of project

	At December 31
	2011		2010		2009
Exploratory well costs capitalized for a period of one year or less	$	557	$	419	$	564
Exploratory well costs capitalized for a period greater than one year		1,877		2,299		1,871
Balance at December 31	$	2,434	$	2,718	$	2,435
Number of projects with exploratory well costs that have been capitalized for a period greater than one year*		47		53		46

* Certain projects have multiple wells or fields or both.

Aging of Costs on Well and Project Basis

			Number
Aging based on drilling completion date of individual wells:	Amount		of wells
1997–2000	$	49		16
2001–2005		396		47
2006–2010		1,432		98
Total	$	1,877		161
Aging based on drilling completion date of last			Number
suspended well in project:	Amount		of projects
1999	$	8		1
2003–2006		345		10
2007–2011		1,524		36
Total	$	1,877		47