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Movement in Capitalised Exploratory Well Costs (Detail) - USD ($) $ in Millions | 12 Months Ended
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Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2016
Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward] |  |  |
At the beginning of the year | $ 668 | $ 770 | $ 484
Additions to capitalised exploratory well costs pending the determination of proved reserves | 186 | 258 | 304
Capitalised exploratory well costs charged to expense | (62) | (69) | (18)
Capitalised exploratory well costs reclassified to wells, equipment, and facilities based on the determination of proved reserves | 2 | (155) |
Other |  | (136) |
At the end of the year | $ 794 | $ 668 | $ 770

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- Definition Amount of other changes in capitalized exploratory well costs. + References No definition available. + Details
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- Definition Additions to capitalized exploratory well costs that were added during the reporting period pending the determination of proved reserves. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 1B -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=68064819&loc=SL6806780-109447 + Details
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- Definition Amount of expense for capitalized exploratory well costs for which proved reserves were not found at the exploratory well. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 1B -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=68064819&loc=SL6806780-109447 + Details
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- Definition The amount of capitalized exploratory well costs that is pending the determination of proved reserves. This does not include amounts that were capitalized and subsequently expensed in the same annual period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 1B -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=68064819&loc=SL6806780-109447 + Details
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
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- Definition Previously capitalized costs of the drilling of wells that were reclassified as part of the costs of the enterprise's wells and related equipment and facilities at the time that proved reserves were found. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 1B -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=68064819&loc=SL6806780-109447 + Details
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