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Share capital - Summary of share capital (Detail) - Rio Tinto plc [member] - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2015
Disclosure Of Classes Of Share Capital [Line Items] |  |
Issued and fully paid up share capital at beginning balance | $ 224 | $ 230
Shares purchased and cancelled | (4) | (6)
Issued and fully paid up share capital at ending balance | $ 220 | $ 224

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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. + Details
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- Definition The nominal value of capital issued. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2016-01-13 -Paragraph 78 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2016-03-30&anchor=para_78_e&doctype=Standard -URIDate 2016-03-31 + Details
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- Definition The decrease in equity resulting from a reduction in issued capital. [Refer: Issued capital] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2016-01-13 -Paragraph 106 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2016-03-30&anchor=para_106_d&doctype=Standard -URIDate 2016-03-31 + Details
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- Details
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