Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment [Abstract]

Components of Property, Plant and Equipment

Property, plant and equipment at December 31 were as follows:

	2020		2019
	(In millions)
Exploration and Production
Unproved properties	$	164	$	168
Proved properties	2,930		3,304
Wells, equipment and related facilities	23,224		28,404
	26,318		31,876
Midstream	4,163		3,904
Corporate and Other	38		40
Total — at cost	30,519		35,820
Less: Reserves for depreciation, depletion, amortization and lease impairment	16,404		19,006
Property, Plant and Equipment — Net	$	14,115	$	16,814

Net Changes in Capitalized Exploratory Well Costs

Capitalized Exploratory Well Costs:  The following table discloses the amount of capitalized exploratory well costs pending determination of proved reserves at December 31 and the changes therein during the respective years:

	2020		2019		2018
	(In millions)
Balance at January 1	$	584	$	418	$	304
Additions to capitalized exploratory well costs pending the determination of proved reserves	111		224		128
Reclassifications to wells, facilities and equipment based on the determination of proved reserves	(111)		(58)		—
Capitalized exploratory well costs charged to expense	(125)		—		(14)
Balance at December 31	$	459	$	584	$	418
Number of Wells at December 31	22		31		24

Exploratory Drilling Costs Capitalized in Excess of One Year After Completion of Drilling

Exploratory well costs capitalized for greater than one year following completion of drilling were $342 million at December 31, 2020, separated by year of completion as follows (in millions):

2019	$	173
2018	105
2017	27
2016	—
2015	37
	$	342