The amount of dividends proposed or declared after the reporting period but before financial statements are authorised for issue. Such dividends are not recognised as a liability at the end of the reporting period because no obligation exists at that time.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 137
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_137_a&doctype=Standard
-URIDate 2019-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 10
-IssueDate 2019-01-01
-Paragraph 13
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=10&code=ifrs-tx-2019-en-r&anchor=para_13&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_DividendsProposedOrDeclaredBeforeFinancialStatementsAuthorisedForIssueButNotRecognisedAsDistributionToOwners
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount, per share, of dividends proposed or declared before financial statements were authorised for issue but not recognised as distribution to owners.

+ References

+ Details

Name:	ifrs-full_DividendsProposedOrDeclaredBeforeFinancialStatementsAuthorisedForIssueButNotRecognisedAsDistributionToOwnersPerShare
Namespace Prefix:	ifrs-full_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of shares in the entity held by the entity or by its subsidiaries or associates. [Refer: Associates [member]; Subsidiaries [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 79
-Subparagraph a
-Clause vi
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_79_a_vi&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_SharesInEntityHeldByEntityOrByItsSubsidiariesOrAssociates
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Disclosure of Dividends [Line Items]

+ References

No definition available.

+ Details

Name:	rio_DisclosureOfDividendsLineItems
Namespace Prefix:	rio_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of dividendsper share relating to the current year, recognised as distributions to owners of the parent.

+ References

No definition available.

+ Details

Name:	rio_DividendsPerShareAsDistributionsToOwnersOfParentRelatingToCurrentYear
Namespace Prefix:	rio_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of dividends per share relating to prior years, recognised as distributions to owners of the parent.

+ References

No definition available.

+ Details

Name:	rio_DividendsPerShareAsDistributionsToOwnersOfParentRelatingToPriorYears
Namespace Prefix:	rio_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of share excluded from final dividend calculation.

+ References

No definition available.

+ Details

Name:	rio_NumberOfShareExcludedFromFinalDividendCalculation
Namespace Prefix:	rio_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of share excluded from interim dividend calculation.

+ References

No definition available.

+ Details

Name:	rio_NumberOfShareExcludedFromInterimDividendCalculation
Namespace Prefix:	rio_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Retained Profits And Reserves That Could Be Distributed As Fully Franked Dividends

+ References

No definition available.

+ Details

Name:	rio_RetainedProfitsAndReservesThatCouldBeDistributedAsFullyFrankedDividends
Namespace Prefix:	rio_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	rio_DividendTypeAxis=rio_FinalDividendsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rio_DividendTypeAxis=rio_SpecialDividendsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_NonadjustingEventsAfterReportingPeriodAxis=ifrs-full_PotentialOrdinaryShareTransactionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=rio_RioTintoPlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfShareCapitalAxis=ifrs-full_OrdinarySharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfShareCapitalAxis=rio_AmericanDepositoryReceiptsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=rio_RioTintoLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Dividends - Additional information (Detail) $ / shares in Units, $ in Millions		12 Months Ended
	Feb. 26, 2020 USD ($) $ / shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) £ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) £ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) £ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares
Disclosure of Dividends [Line Items]
Number of shares held		0	0	0	0	0	0	0	0	0
Final Dividends [Member]
Disclosure of Dividends [Line Items]
Dividends per share: proposed in the announcement of the results for the year \| $ / shares		$ 2.310			$ 1.800			$ 1.800
Special Dividends [Member]
Disclosure of Dividends [Line Items]
Dividends per share: proposed in the announcement of the results for the year \| $ / shares		0.000			2.430			0.000
Potential ordinary share transactions [Member]
Disclosure of Dividends [Line Items]
Dividends per share: proposed in the announcement of the results for the year \| $ / shares	$ 2.31
Dividends payment proposed in the announcement of the results for the year \| $	$ 3,700
Rio Tinto plc [Member] \| Final Dividends [Member]
Disclosure of Dividends [Line Items]
Final dividend per share \| (per share)		1.800	£ 1.3596		1.800	£ 1.2943		1.250	£ 1.0056
Interim dividend per share \| (per share)		1.510	1.2332		1.270	0.9682		1.100	0.8313
Rio Tinto plc [Member] \| Special Dividends [Member]
Disclosure of Dividends [Line Items]
Final dividend per share \| (per share)		2.430	1.8355		$ 0.0000			$ 0.0000
Interim dividend per share \| (per share)		$ 0.610	£ 0.4982			£ 0.0000			£ 0.0000
Rio Tinto plc [Member] \| Ordinary [Member]
Disclosure of Dividends [Line Items]
Number of share excluded from previous year final dividend calculation		852,283	852,283	852,283	132,294	132,294	132,294	277,946	277,946	277,946
Number of share excluded from interim dividend calculation		564,099	564,099	564,099	314,529	314,529	314,529	173,297	173,297	173,297
Rio Tinto plc [Member] \| American depository receipts
Disclosure of Dividends [Line Items]
Number of share excluded from previous year final dividend calculation		37,678	37,678	37,678	22,824	22,824	22,824	22,021	22,021	22,021
Number of share excluded from interim dividend calculation		47,674	47,674	47,674	36,321	36,321	36,321	24,377	24,377	24,377
Rio Tinto Limited [Member]
Disclosure of Dividends [Line Items]
Number of share excluded from previous year final dividend calculation		628,566	628,566	628,566	130,129	130,129	130,129	214,278	214,278	214,278
Number of share excluded from interim dividend calculation		342,062	342,062	342,062	251,394	251,394	251,394	274,899	274,899	274,899
Number of shares held		944,467	944,467	944,467
Retained profits and reserves distributed as dividends \| $		$ 8,599	£ 8,599	$ 8,599	$ 6,178	£ 6,178	$ 6,178	$ 8,542	£ 8,542	$ 8,542
Rio Tinto Limited [Member] \| Final Dividends [Member]
Disclosure of Dividends [Line Items]
Final dividend per share \| $ / shares				$ 2.5089			$ 2.2853			$ 1.6362
Interim dividend per share \| $ / shares				2.1908			1.7084			1.3772
Rio Tinto Limited [Member] \| Special Dividends [Member]
Disclosure of Dividends [Line Items]
Final dividend per share \| $ / shares				3.3870			0.0000			0.0000
Interim dividend per share \| $ / shares				$ 0.8850			$ 0.000			$ 0.000