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Purchases and sales of subsidiaries, joint ventures, associates and other interests in businesses - Additional information (Detail) - USD ($) |  |  |  |  |  |  |  |  |  | 1 Months Ended | 12 Months Ended
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Dec. 21, 2018 | Dec. 14, 2018 | Aug. 01, 2018 | Jun. 01, 2018 | May 10, 2018 | Sep. 01, 2017 | Nov. 23, 2016 | Jul. 20, 2016 | Mar. 01, 2016 | May 31, 2017 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchased amount |  |  |  |  |  |  |  |  |  | $ 194,000,000 |  |  |  |  |
Current trade receivables |  |  |  |  |  |  |  |  |  |  |  |  | $ 2,167,000,000 | $ 2,314,000,000 |
Profit before taxation |  |  |  |  |  |  |  |  |  |  |  |  | 18,167,000,000 | 12,816,000,000 | $ 6,343,000,000
Disposals of subsidiaries, joint ventures, unincorporated joint operations, and associates |  |  |  |  |  |  |  |  |  |  |  |  | 7,733,000,000 | 2,675,000,000 | 761,000,000
2018 Disposals [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disposal amount |  |  | $ 1,700,000,000 |  |  |  |  |  |  |  |  |  |  |  |
2017 disposals [member] | Yancoal Australia Limited [member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disposal amount |  |  |  |  |  | $ 2,690,000,000 |  |  |  |  |  |  |  |  |
Ownership interest in joint venture disposed |  |  |  |  |  | 100.00% |  |  |  |  |  |  |  |  |
Cash consideration for disposal |  |  |  |  |  | $ 2,450,000,000 |  |  |  |  |  |  |  | 2,540,000,000 |
Expected unconditional royalty payments to be received |  |  |  |  |  | $ 240,000,000 |  |  |  |  |  |  |  |  |
Unconditional guaranteed royalty payments received |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 110,000,000 |
Unconditional guaranteed royalty received |  |  |  |  |  |  |  |  |  |  |  |  | 90,000,000 |  |
Expected unconditional royalty payments |  |  |  |  |  |  |  |  |  |  |  |  | $ 40,000,000 |  |
2016 disposals [member] | New hope corporation limited [member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disposal amount |  |  |  |  |  |  |  |  | $ 617,000,000 |  |  |  |  |  |
Ownership interest in joint venture disposed |  |  |  |  |  |  |  |  | 40.00% |  |  |  |  |  |
2016 disposals [member] | SIMEC [member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disposal amount |  |  |  |  |  |  | $ 410,000,000 |  |  |  |  |  |  |  |
Cash received |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 224,000,000
Simfer Jersey Limited [member] | Ordinary shares [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of purchased interest |  |  |  |  |  |  |  |  |  | 53.00% |  |  |  |  |
Non-controlling interest (%), Subsidiary |  |  |  |  |  |  |  |  |  |  |  |  | 47.00% |  |
Simfer S.A. [member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of purchased interest |  |  |  |  |  |  |  |  |  | 4.25% |  |  |  |  |
Non-controlling interest (%), Subsidiary |  |  |  |  |  |  |  |  |  |  |  |  | 45.05% |  |
Simfer S.A. [member] | 2016 disposals [member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of non-contributory shares |  |  |  |  |  |  |  | 7.50% |  |  |  |  |  |  |
Percentage of ordinary contributory shares upon second tranche |  |  |  |  |  |  |  | 10.00% |  |  |  |  |  |  |
Percentage of ordinary contributory shares |  |  |  |  |  |  |  | 5.00% |  |  |  |  |  |  |
Simfer S.A. [member] | Bottom of range [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of purchased interest |  |  |  |  |  |  |  |  |  | 42.80% |  |  |  |  |
Simfer S.A. [member] | Top of range [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of purchased interest |  |  |  |  |  |  |  |  |  | 45.05% |  |  |  |  |
Dunkerque Aluminium Smelter [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disposal amount |  | $ 500,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Profit before taxation |  | $ 128,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from sale of a business |  |  |  |  |  |  |  |  |  |  |  |  | $ 385,000,000 |  |
Cash received from disposals |  |  |  |  |  |  |  |  |  |  |  |  | 52,000,000 |  |
Grasberg [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disposal amount | $ 3,500,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gains on disposals of projects | 2,146,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disposals of subsidiaries, joint ventures, unincorporated joint operations, and associates | $ 3,392,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Grasberg [Member] | Copper and Gold Revenues [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues, net of capital contribution. |  |  |  |  |  |  |  |  |  |  |  |  | $ 107,000,000 |  |
Carbone savoie [Member] | 2016 disposals [member] | Alandia industries [member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest in cash generating units disposed |  |  |  |  |  |  |  |  |  |  |  | 100.00% |  |  |
Bougainville Copper Limited [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Non-controlling interest (%), Subsidiary |  |  |  |  |  |  |  |  |  |  |  |  |  | 36.40% |
Bougainville Copper Limited [Member] | Equity Trustees Limited [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disposal amount |  |  |  |  |  |  |  |  |  |  | $ 0 |  |  |  |
Percentage of share holding transferred |  |  |  |  |  |  |  |  |  |  | 53.83% |  |  |  |
Bougainville Copper Limited [Member] | Autonomous Bougainville Government [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of ownership shares distributed |  |  |  |  |  |  |  |  |  |  |  |  |  | 36.40% |
Bougainville Copper Limited [Member] | Independent State of Papua New Guinea [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of ownership shares distributed |  |  |  |  |  |  |  |  |  |  |  |  |  | 17.40% |
Lochaber [member] | 2016 disposals [member] | SIMEC [member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportion of ownership interest disposed |  |  |  |  |  |  | 100.00% |  |  |  |  |  |  |  |
Elysis |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash investment in joint venture |  |  |  |  | $ 5,000,000 |  |  |  |  |  |  |  |  |  |
Fare value of patents |  |  |  |  | 171,000,000 |  |  |  |  |  |  |  |  |  |
Fair value of intellectual property |  |  |  |  | $ 141,000,000 |  |  |  |  |  |  |  |  |  |
Whitehaven Coal Limited [Member] | 2018 Disposals [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disposal amount |  |  |  | $ 200,000,000 |  |  |  |  |  |  |  |  |  |  |
Ownership interest in joint venture disposed |  |  |  | 75.00% |  |  |  |  |  |  |  |  |  |  |
Cash received from disposals |  |  |  | $ 150,000,000 |  |  |  |  |  |  |  |  |  |  |
Gains on disposals of projects |  |  |  | 195,000,000 |  |  |  |  |  |  |  |  |  |  |
Whitehaven Coal Limited [Member] | Due within 1 year [member] | 2018 Disposals [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Current trade receivables |  |  |  | $ 50,000,000 |  |  |  |  |  |  |  |  |  |  |
Hail Creek [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Profit before taxation |  |  | $ 1,141,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Hail Creek [Member] | 2018 Disposals [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest in joint venture disposed |  |  | 82.00% |  |  |  |  |  |  |  |  |  |  |  |
Net proceeds disposal of project |  |  | $ 1,545,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Profit before taxation |  |  | $ 1,141,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Valeria Project [Member] | 2018 Disposals [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest in joint venture disposed |  |  | 71.20% |  |  |  |  |  |  |  |  |  |  |  |
Net proceeds disposal of project |  |  | $ 170,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Valeria Project [Member] | 2018 Disposals [Member] | Land and Investments [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net proceeds disposal of project |  |  | 87,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Profit before taxation |  |  | 18,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Valeria Project [Member] | 2018 Disposals [Member] | Undeveloped Properties [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash received from disposals |  |  | 83,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Profit before taxation |  |  | 83,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Kestrel Underground Coal Mine [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Profit before taxation |  |  | 1,010,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Kestrel Underground Coal Mine [Member] | 2018 Disposals [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disclosure Of Acquisitions And Disposals [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Disposal amount |  |  | $ 2,250,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest in joint venture disposed |  |  | 80.00% |  |  |  |  |  |  |  |  |  |  |  |
Net proceeds disposal of project |  |  | $ 2,270,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Profit before taxation |  |  | $ 1,010,000,000 |  |  |  |  |  |  |  |  |  |  |  |

X
- Definition The amount of cash and cash equivalents in subsidiaries or other businesses over which control is obtained or lost. [Refer: Subsidiaries [member]; Cash and cash equivalents] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2017-01-01 -Paragraph 40 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2017-03-01&anchor=para_40_c&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition The aggregate cash flows arising from losing control of subsidiaries or other businesses, classified as investing activities. [Refer: Subsidiaries [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2017-01-01 -Paragraph 39 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2017-03-01&anchor=para_39&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition The amount of consideration paid or received in respect of both obtaining and losing control of subsidiaries or other businesses. [Refer: Subsidiaries [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2017-01-01 -Paragraph 40 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2017-03-01&anchor=para_40_a&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition The amount of current trade receivables. [Refer: Trade receivables] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 78 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_78_b&doctype=Standard -URIDate 2017-03-09 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 68 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_68&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition The gain on the disposal of investments. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 98 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_98_d&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition The cash outflow to acquire interests in joint ventures (other than payments for those instruments considered to be cash equivalents or those held for dealing or trading purposes), classified as investing activities. [Refer: Joint ventures [member]] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 7 -IssueDate 2017-01-01 -Paragraph 16 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2017-03-01&anchor=para_16_c&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition The portion of consideration paid or received, consisting of cash and cash equivalents, in respect of both obtaining and losing control of subsidiaries or other businesses. [Refer: Subsidiaries [member]; Cash and cash equivalents; Consideration paid (received)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2017-01-01 -Paragraph 40 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2017-03-01&anchor=para_40_b&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition The cash inflow from the disposal of mining assets. [Refer: Mining assets] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 7 -IssueDate 2017-01-01 -Paragraph 16 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2017-03-01&anchor=para_16&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition The profit (loss) from continuing operations before tax expense or income. [Refer: Profit (loss)] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 8 -IssueDate 2017-01-01 -Paragraph 28 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=8&date=2017-03-01&anchor=para_28_b&doctype=Standard -URIDate 2017-03-09 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 8 -IssueDate 2017-01-01 -Paragraph 23 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=8&date=2017-03-01&anchor=para_23&doctype=Standard -URIDate 2017-03-09 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 103 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_103&doctype=Standard -URIDate 2017-03-09 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 102 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_102&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition The proportion of ownership interests in a subsidiary held by non-controlling interests. [Refer: Subsidiaries [member]; Non-controlling interests] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2017-01-01 -Paragraph 12 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2017-03-01&anchor=para_12_c&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition Cash flows from disposal of project or other businesses classified operating activities. + References No definition available. + Details
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- Definition Expected unconditional guaranteed royalty payments. + References No definition available. + Details
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