The number of projects for which exploratory well costs have been capitalized for a period of greater than one year after the completion of drilling.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 1B
-Subparagraph b
-URI http://asc.fasb.org/extlink&oid=68064819&loc=SL6806780-109447

Name:	us-gaap_ProjectsThatHaveExploratoryWellCostsThatHaveBeenCapitalizedForPeriodGreaterThanOneYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Number of Projects with Exploratory Well Costs (Detail) - Project	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Exploratory Wells Drilled [Line Items]
Number of projects that only have exploratory well costs capitalized for a period of one year or less
Number of projects that have exploratory well costs capitalized for a period of greater than one year
Total projects