Property, Plant and Equipment - Additional Information (Detail) $ in Millions	12 Months Ended
Jun. 30, 2020 USD ($) $ / bbl	Jun. 30, 2019 USD ($)
Disclosure of detailed information about property, plant and equipment [abstract]
Commitments for capital expenditure	$ 2,585	$ 3,308
Reversals of impairment	$ 0
Price Per barrel \| $ / bbl	55

The amount of reversal of impairment loss recognised in profit or loss for property, plant and equipment. [Refer: Reversal of impairment loss recognised in profit or loss; Property, plant and equipment]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 16
-IssueDate 2019-01-01
-Paragraph 73
-Subparagraph e
-Clause vi
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=16&code=ifrs-tx-2019-en-r&anchor=para_73_e_vi&doctype=Standard
-URIDate 2019-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 98
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_98_a&doctype=Standard
-URIDate 2019-03-27

Name:	ifrs-full_ReversalOfImpairmentLossRecognisedInProfitOrLossPropertyPlantAndEquipment
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration