XML 282 R275.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Investments - Investments in Group companies (Detail) - Rio Tinto plc [member] - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016
Disclosure Of Investments In Subsidiaries Joint Ventures And Associates [Abstract] |  |
Investments in Group companies, beginning balance | $ 36,050 | $ 36,180
Additions | 45 | 58
Disposals |  | (160)
Other adjustments | (2) | (28)
Investments in Group companies, ending balance | $ 36,093 | $ 36,050

X
- Definition The amount of investments in subsidiaries, joint ventures and associates in an entity's separate financial statements. [Refer: Associates [member]; Joint ventures [member]; Subsidiaries [member]; Investments in subsidiaries] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2016-01-13 -Paragraph 55 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2016-03-30&anchor=para_55&doctype=Standard -URIDate 2016-03-31 + Details
Name: | ifrs-full_InvestmentsInSubsidiariesJointVenturesAndAssociates
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Additions to investments in subsidiaries joint ventures and associates. + References No definition available. + Details
Name: | rio_AdditionsToInvestmentsInSubsidiariesJointVenturesAndAssociates
Namespace Prefix: | rio_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Disclosure of investments in subsidiaries joint ventures and associates. + References No definition available. + Details
Name: | rio_DisclosureOfInvestmentsInSubsidiariesJointVenturesAndAssociatesAbstract
Namespace Prefix: | rio_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Disposals from investments in subsidiaries joint ventures and associates. + References No definition available. + Details
Name: | rio_DisposalsFromInvestmentsInSubsidiariesJointVenturesAndAssociates
Namespace Prefix: | rio_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Other adjustments to investments in subsidiaries joint ventures and associates. + References No definition available. + Details
Name: | rio_OtherAdjustmentsToInvestmentsInSubsidiariesJointVenturesAndAssociates
Namespace Prefix: | rio_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=rio_RioTintoPlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |