Interests in Joint Operations - Summary of Significant Interests in Joint Operations (Detail)	12 Months Ended
Jun. 30, 2018	Jun. 30, 2017
Bass Strait Australia [member]
Disclosure of significant joint operations [Line Items]
Country of operation	Australia
Principal activity	Hydrocarbons production
Group interest	50.00%	50.00%
Greater Angostura Trinidad and Tobago [member]
Disclosure of significant joint operations [Line Items]
Country of operation	Trinidad and Tobago
Principal activity	Hydrocarbons production
Group interest	45.00%	45.00%
Gulf of Mexico United States [member]
Disclosure of significant joint operations [Line Items]
Country of operation	US
Principal activity	Hydrocarbons exploration and production
Gulf of Mexico United States [member] \| Bottom of range [Member]
Disclosure of significant joint operations [Line Items]
Group interest	23.90%	23.90%
Gulf of Mexico United States [member] \| Top of range [Member]
Disclosure of significant joint operations [Line Items]
Group interest	44.00%	44.00%
Macedon Australia [member]
Disclosure of significant joint operations [Line Items]
Country of operation	Australia
Principal activity	Hydrocarbons exploration and production
Group interest	71.43%	71.43%
North West Shelf Australia [member]
Disclosure of significant joint operations [Line Items]
Country of operation	Australia
Principal activity	Hydrocarbons production
North West Shelf Australia [member] \| Bottom of range [Member]
Disclosure of significant joint operations [Line Items]
Group interest	12.50%	12.50%
North West Shelf Australia [member] \| Top of range [Member]
Disclosure of significant joint operations [Line Items]
Group interest	16.67%	16.67%
Pyrenees Australia [member]
Disclosure of significant joint operations [Line Items]
Country of operation	Australia
Principal activity	Hydrocarbons exploration and production
Pyrenees Australia [member] \| Bottom of range [Member]
Disclosure of significant joint operations [Line Items]
Group interest	40.00%	40.00%
Pyrenees Australia [member] \| Top of range [Member]
Disclosure of significant joint operations [Line Items]
Group interest	71.43%	71.43%
ROD Integrated Development Algeria [member]
Disclosure of significant joint operations [Line Items]
Country of operation	Algeria
Principal activity	Hydrocarbons exploration and production
Group interest	29.50%	29.50%
Mt Goldsworthy Australia [member]
Disclosure of significant joint operations [Line Items]
Country of operation	Australia
Principal activity	Iron ore mining
Group interest	85.00%	85.00%
Mt Newmen Australia [member]
Disclosure of significant joint operations [Line Items]
Country of operation	Australia
Principal activity	Iron ore mining
Group interest	85.00%	85.00%
Yandi Australia [member]
Disclosure of significant joint operations [Line Items]
Country of operation	Australia
Principal activity	Iron ore mining
Group interest	85.00%	85.00%
Central Queensland Coal Associates Australia [member]
Disclosure of significant joint operations [Line Items]
Country of operation	Australia
Principal activity	Coal mining
Group interest	50.00%	50.00%

The description of the nature of the entity's operations and principal activities.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 138
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_138_b&doctype=Standard
-URIDate 2017-03-09

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- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

+ References

No definition available.

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- Definition

The principal place of business of a joint operation. [Refer: Joint operations [member]; Principal place of business]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2017-01-01
-Paragraph 21
-Subparagraph a
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2017-03-01&anchor=para_21_a_iii&doctype=Standard
-URIDate 2017-03-09

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- Definition

The proportion of ownership interest in a joint operation attributable to the entity. [Refer: Joint operations [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2017-01-01
-Paragraph 21
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-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2017-03-01&anchor=para_21_a_iv&doctype=Standard
-URIDate 2017-03-09

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