Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2019

Property Plant And Equipment [Abstract]

Components of Property, Plant and Equipment

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

	2019		2018
	(In millions)
Exploration and Production
Unproved properties	$	168	$	394
Proved properties		3,304		3,124
Wells, equipment and related facilities		28,404		26,173
		31,876		29,691
Midstream		3,904		3,492
Corporate and Other		40		39
Total — at cost		35,820		33,222
Less: Reserves for depreciation, depletion, amortization and lease impairment		19,006		17,139
Property, Plant and Equipment — Net	$	16,814	$	16,083

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:

	2019			2018			2017
	(In millions)
Balance at January 1	$	418		$	304		$	597
Additions to capitalized exploratory well costs pending the determination of proved reserves		224			128			116
Reclassifications to wells, facilities and equipment based on the determination of proved reserves		(58	)		—			(165	)
Capitalized exploratory well costs charged to expense		—			(14	)		(268	)
Dispositions and other		—			—			24
Balance at December 31	$	584		$	418		$	304
Number of Wells at December 31		31			24			12

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 $400 million at December 31, 2019, separated by year of completion as follows (in millions):

2018	$	157
2017		73
2016		—
2015		166
2014 and prior		4
	$	400