XML 193 R186.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Other reserves and retained earnings - Summary of other reserves and retained earnings (Parenthetical) (Detail) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Disclosure Of Other Reserves And Retained Earnings [Line Items] |  |  |
Share premium account | $ 4,306,000,000 | $ 4,304,000,000 |
Other reserve, share premium | 12,284,000,000 | 9,216,000,000 |
Actuarial losses to equity accounted units | (855,000,000) | (1,120,000,000) | $ 548,000,000
Investment in equity accounted units [member] |  |  |
Disclosure Of Other Reserves And Retained Earnings [Line Items] |  |  |
Actuarial losses to equity accounted units | 0 | $ 0 | $ 0
Share premium [Member] |  |  |
Disclosure Of Other Reserves And Retained Earnings [Line Items] |  |  |
Share premium account | 0 |  |
Merger reserve [Member] |  |  |
Disclosure Of Other Reserves And Retained Earnings [Line Items] |  |  |
Other reserve, share premium | $ 11,936,000,000 |  |

X
- Definition The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in financial assumptions that result in remeasurements of the net defined benefit liability (asset). Financial assumptions deal with items such as: (a) the discount rate; (b) benefit levels, excluding any cost of the benefits to be met by employees, and future salary; (c) in the case of medical benefits, future medical costs, including claim handling costs (ie the costs that will be incurred in processing and resolving claims, including legal and adjuster's fees); and (d) taxes payable by the plan on contributions relating to service before the reporting date or on benefits resulting from that service. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2016-01-13 -Paragraph 141 -Subparagraph c -Clause iii -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2016-03-30&anchor=para_141_c_iii&doctype=Standard -URIDate 2016-03-31 + Details
Name: | ifrs-full_ActuarialGainsLossesArisingFromChangesInFinancialAssumptionsNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition A component of equity representing reserves within equity, not including retained earnings. [Refer: Retained earnings] + 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
Name: | ifrs-full_OtherReserves
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount received or receivable from the issuance of the entity's shares in excess of nominal value. + 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
Name: | ifrs-full_SharePremium
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Disclosure of other reserves and retained earnings [Line Items] + References No definition available. + Details
Name: | rio_DisclosureOfOtherReservesAndRetainedEarningsLineItems
Namespace Prefix: | rio_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_ClassesOfAssetsAxis=ifrs-full_InvestmentsAccountedForUsingEquityMethodMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ComponentsOfEquityAxis=ifrs-full_SharePremiumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ComponentsOfEquityAxis=ifrs-full_MergerReserveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |