XML 453 R250.htm IDEA: XBRL DOCUMENT v3.10.0.1

Post-retirement benefits - Summary of maturity of defined benefit obligations (Detail) - yr	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of defined benefit plans [Line Items]
Proportion relating to current employees	19.00%	20.00%	21.00%
Proportion relating to former employees not yet retired	11.00%	11.00%	12.00%
Proportion relating to retirees	70.00%	69.00%	67.00%
Defined benefit obligation	100.00%	100.00%	100.00%
Average duration of obligations (years)	13.4	13.9	14.3
Pension benefits [member]
Disclosure of defined benefit plans [Line Items]
Proportion relating to current employees	20.00%
Proportion relating to former employees not yet retired	11.00%
Proportion relating to retirees	69.00%
Defined benefit obligation	100.00%
Average duration of obligations (years)	13.4
Other Benefits [member]
Disclosure of defined benefit plans [Line Items]
Proportion relating to current employees	15.00%
Proportion relating to former employees not yet retired	2.00%
Proportion relating to retirees	83.00%
Defined benefit obligation	100.00%
Average duration of obligations (years)	12.7

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

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

X

- Definition

The weighted average duration of a defined benefit obligation. [Refer: Weighted average [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2017-01-01
-Paragraph 147
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_147_c&doctype=Standard
-URIDate 2017-03-09

+ Details

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

X

- Definition

Defined benefit obligation maturity percentage.

+ References

No definition available.

+ Details

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

X

- Definition

Defined benefit obligations relating to current employees maturity percentage.

+ References

No definition available.

+ Details

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

X

- Definition

Defined benefit obligations relating to former employees not yet retired maturity percentage.

+ References

No definition available.

+ Details

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

X

- Definition

Defined benefit obligations relating to retirees maturity percentage.

+ References

No definition available.

+ Details

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

X

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: