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Principal joint operations - Summary of principle joint operations (Detail) | 12 Months Ended
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Dec. 31, 2018
Tomago Aluminium Joint Venture [member] |
Disclosure Of Joint Operations [Line Items] |
Company of operation, Joint Operation | Tomago Aluminium Joint Venture
Country of incorporation, Joint Operation | Australia
Principal activities, Joint Operation | Aluminium smelting
Group interest (%), Joint Operation | 51.60%
Gladstone Power Station [member] |
Disclosure Of Joint Operations [Line Items] |
Company of operation, Joint Operation | Gladstone Power Station
Country of incorporation, Joint Operation | Australia
Principal activities, Joint Operation | Power generation
Group interest (%), Joint Operation | 42.10%
Hope Downs Joint Venture [member] |
Disclosure Of Joint Operations [Line Items] |
Company of operation, Joint Operation | Hope Downs Joint Venture
Country of incorporation, Joint Operation | Australia
Principal activities, Joint Operation | Iron ore mining
Group interest (%), Joint Operation | 50.00%
Queensland Alumina Limited [member] |
Disclosure Of Joint Operations [Line Items] |
Company of operation, Joint Operation | Queensland Alumina Limited
Country of incorporation, Joint Operation | Australia
Principal activities, Joint Operation | Alumina production
Group interest (%), Joint Operation | 80.00%
Pilbara Iron arrangement [Member] |
Disclosure Of Joint Operations [Line Items] |
Company of operation, Joint Operation | Pilbara Iron arrangement
Country of incorporation, Joint Operation | Australia
Principal activities, Joint Operation | Infrastructure, corporate and mining services
New Zealand Aluminium Smelters Limited [member] |
Disclosure Of Joint Operations [Line Items] |
Company of operation, Joint Operation | New Zealand Aluminium Smelters Limited
Country of incorporation, Joint Operation | New Zealand
Principal activities, Joint Operation | Aluminium smelting
Group interest (%), Joint Operation | 79.36%
Aluminerie Alouette Inc. [member] |
Disclosure Of Joint Operations [Line Items] |
Company of operation, Joint Operation | Aluminerie Alouette Inc.
Country of incorporation, Joint Operation | Canada
Principal activities, Joint Operation | Aluminium production
Group interest (%), Joint Operation | 40.00%
Pechiney Reynolds Quebec Inc [member] |
Disclosure Of Joint Operations [Line Items] |
Company of operation, Joint Operation | Pechiney Reynolds Quebec Inc
Country of incorporation, Joint Operation | United States of America
Principal activities, Joint Operation | Aluminium smelting
Group interest (%), Joint Operation | 50.20%

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- Definition The description of the nature of the entity's relationship with a joint operation (for example, describing the nature of the activities of the joint operation and whether they are strategic to the entity's activities). [Refer: Joint operations [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2017-01-01 -Paragraph 21 -Subparagraph a -Clause ii -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2017-03-01&anchor=para_21_a_ii&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition The name of a joint operation. [Refer: Joint operations [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2017-01-01 -Paragraph 21 -Subparagraph a -Clause i -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2017-03-01&anchor=para_21_a_i&doctype=Standard -URIDate 2017-03-09 + Details
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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 -Subparagraph a -Clause iv -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 + Details
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