XML 458 R255.htm IDEA: XBRL DOCUMENT v3.10.0.1

Post-retirement benefits - Summary of funding policy and contributions to plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of net defined benefit liability (asset) [Line Items]
Contributions to defined benefit plans	$ 248	$ 404	$ 464
Contributions to defined contribution plans	244	243	240
Contributions to industry-wide plans		12	17
Total	492	$ 659	$ 721
Pension benefits [member]
Disclosure of net defined benefit liability (asset) [Line Items]
Contributions to defined benefit plans	204
Contributions to defined contribution plans	242
Total	446
Other Benefits [member]
Disclosure of net defined benefit liability (asset) [Line Items]
Contributions to defined benefit plans	44
Contributions to defined contribution plans	2
Total	$ 46

X

- Definition

The decrease (increase) in net defined benefit liability (asset) resulting from contributions to a defined benefit plan by the employer. [Refer: Net defined benefit liability (asset); Defined benefit plans [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2017-01-01
-Paragraph 141
-Subparagraph f
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_141_f&doctype=Standard
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_ContributionsToPlanByEmployerNetDefinedBenefitLiabilityAsset
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

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

X

- Definition

The amount of employer contributions to retirement benefit plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 26
-IssueDate 2017-01-01
-Paragraph 35
-Subparagraph b
-Clause i
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=26&date=2017-03-01&anchor=para_35_b_i&doctype=Standard
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_EmployerContributions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Contributions to Defined Contribution Plans

+ References

No definition available.

+ Details

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

X

- Definition

The decrease (increase) in the net defined benefit liability (asset) resulting from employer contributions to industry wide plans.

+ References

No definition available.

+ Details

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

X

- Details

Name:	ifrs-full_DefinedBenefitPlansAxis=rio_DefinedBenefitPensionPlansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_DefinedBenefitPlansAxis=rio_OtherDefinedBenefitPlansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: