XML 399 R196.htm IDEA: XBRL DOCUMENT v3.10.0.1

Financial instruments and risk management - Summary of changes in market price relevant to alumina purchase price swaps outstanding (Detail) - Commodity price risk [Member] - Aluminium [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Effect on net earnings [Member]
Disclosure Of Financial Instruments [Line Items]
Percentage increase in market price change	10.00%
Percentage decrease in market price change	(10.00%)
Decrease in market price change of commodities	$ (102)	$ (203)
Increase in market price change of commodities	$ 35	$ 212
Effect on equity [Member]
Disclosure Of Financial Instruments [Line Items]
Percentage increase in market price change	10.00%
Percentage decrease in market price change	(10.00%)
Decrease in market price change of commodities	$ (101)
Increase in market price change of commodities	$ 103

X

- 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

Name:	ifrs-full_DisclosureOfFinancialInstrumentsLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Decrease) in market price change of commodities.

+ References

No definition available.

+ Details

Name:	rio_DecreaseInMarketPriceChangeOfCommodities
Namespace Prefix:	rio_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Increase in market price change of commodities.

+ References

No definition available.

+ Details

Name:	rio_IncreaseInMarketPriceChangeOfCommodities
Namespace Prefix:	rio_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Percentage Of Decrease In Market Price On Commodity Derivatives.

+ References

No definition available.

+ Details

Name:	rio_PercentageOfDecreaseInMarketPriceOnCommodityDerivatives
Namespace Prefix:	rio_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of increase in market price on commodity derivatives.

+ References

No definition available.

+ Details

Name:	rio_PercentageOfIncreaseInMarketPriceOnCommodityDerivatives
Namespace Prefix:	rio_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	ifrs-full_ClassesOfFinancialAssetsAxis=rio_EffectOnNetEarningsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_TypesOfRisksAxis=ifrs-full_CommodityPriceRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ProductsAndServicesAxis=rio_AluminiumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ClassesOfFinancialAssetsAxis=rio_EffectOfEquityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: