Accounting for Suspended Exploratory Wells (Tables)

12 Months Ended

Dec. 31, 2019

Accounting for Suspended Exploratory Wells [Abstract]

Changes in company's suspended exploratory well costs

The following table indicates the changes to the company’s suspended exploratory well costs for the three years ended December 31, 2019:



	2019			2018			2017
Beginning balance at January 1	$	3,563		$	3,702		$	3,540
Additions to capitalized exploratory well costs pending the determination of proved reserves	244			207			323
Reclassifications to wells, facilities and equipment based on the determination of proved reserves	(500		)	(13		)	(113		)
Capitalized exploratory well costs charged to expense	(125		)	(333		)	(39		)
Other reductions^*	(141		)	—			(9		)
Ending balance at December 31	$	3,041		$	3,563		$	3,702

^*Represents property sales.

Aging of capitalized well costs and number of project

The following table provides an aging of capitalized well costs and the number of projects for which exploratory well costs have been capitalized for a period greater than one year since the completion of drilling.



	At December 31
	2019		2018		2017
Exploratory well costs capitalized for a period of one year or less	$	214	$	202	$	307
Exploratory well costs capitalized for a period greater than one year	2,827		3,361		3,395
Balance at December 31	$	3,041	$	3,563	$	3,702
Number of projects with exploratory well costs that have been capitalized for a period greater than one year^*	22		30		32

^*Certain projects have multiple wells or fields or both.

Aging of Costs on Well and Project Basis

The $2,827 of suspended well costs capitalized for a period greater than one year as of December 31, 2019, represents 123 exploratory wells in 22 projects. The tables below contain the aging of these costs on a well and project basis:



Aging based on drilling completion date of individual wells:	Amount		Number of wells
1998-2008	$	244	27
2009-2013	1,166		56
2014-2018	1,417		40
Total	$	2,827	123

Aging based on drilling completion date of last suspended well in project:	Amount		Number of projects
2003-2011	$	318	4
2012-2015	1,653		11
2016-2019	856		7
Total	$	2,827	22