XML 372 R249.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Post-retirement benefits - Summary of movement in present value of obligation (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Disclosure of net defined benefit liability (asset) [Line Items] |  |  |
Beginning balance | $ (1,551) | $ (2,499) |
Changes in net defined benefit liability (asset) [abstract] |  |  |
Current employer service costs | 125 | 165 | $ 155
Past service cost | 0 | 36 | (4)
Curtailment gains | 0 | (2) | (1)
Settlements | (51) | (5) | (1)
Interest | (58) | (79) | (79)
Actuarial losses to equity accounted units | 1,295 | (1,382) | 855
Arrangements divested | (5) | (10) |
Currency exchange rate (loss)/gain | (20) | 91 |
Ending balance | (1,730) | (1,551) | (2,499)
Pension benefits [member] |  |  |
Disclosure of net defined benefit liability (asset) [Line Items] |  |  |
Beginning balance | (680) |  |
Changes in net defined benefit liability (asset) [abstract] |  |  |
Current employer service costs | 119 |  |
Past service cost | 0 |  |
Curtailment gains | 0 |  |
Settlements | (51) |  |
Interest | (22) |  |
Arrangements divested | (5) |  |
Currency exchange rate (loss)/gain | (3) |  |
Ending balance | (831) | (680) |
Other Benefits [member] |  |  |
Disclosure of net defined benefit liability (asset) [Line Items] |  |  |
Beginning balance | (871) |  |
Changes in net defined benefit liability (asset) [abstract] |  |  |
Arrangements divested | 0 |  |
Currency exchange rate (loss)/gain | (17) |  |
Ending balance | (899) | (871) |
Present value of defined benefit obligation [Member] |  |  |
Disclosure of net defined benefit liability (asset) [Line Items] |  |  |
Beginning balance | (14,754) | (17,645) |
Changes in net defined benefit liability (asset) [abstract] |  |  |
Current employer service costs | (125) | (165) |
Past service cost | 0 | (36) |
Curtailment gains | 0 | 2 |
Settlements | 638 | 299 |
Interest | (476) | (503) |
Contributions by plan participants | (23) | (24) |
Benefits paid | 862 | 915 |
Experience gains | 111 | 32 |
Actuarial losses to equity accounted units | (1,447) | 1,349 |
Changes in demographic assumptions gain/(loss) | 41 | 1 |
Arrangements divested | (5) | 94 |
Currency exchange rate (loss)/gain | (475) | 927 |
Ending balance | (15,653) | (14,754) | $ (17,645)
Present value of defined benefit obligation [Member] | Pension benefits [member] |  |  |
Disclosure of net defined benefit liability (asset) [Line Items] |  |  |
Beginning balance | (13,883) |  |
Changes in net defined benefit liability (asset) [abstract] |  |  |
Current employer service costs | (119) |  |
Past service cost | 0 |  |
Curtailment gains | 0 |  |
Settlements | 638 |  |
Interest | (440) |  |
Contributions by plan participants | (23) |  |
Benefits paid | 828 |  |
Experience gains | 48 |  |
Actuarial losses to equity accounted units | (1,355) |  |
Changes in demographic assumptions gain/(loss) | 15 |  |
Arrangements divested | (5) |  |
Currency exchange rate (loss)/gain | (458) |  |
Ending balance | (14,754) | (13,883) |
Present value of defined benefit obligation [Member] | Other Benefits [member] |  |  |
Disclosure of net defined benefit liability (asset) [Line Items] |  |  |
Beginning balance | (871) |  |
Changes in net defined benefit liability (asset) [abstract] |  |  |
Current employer service costs | (6) |  |
Past service cost | 0 |  |
Curtailment gains | 0 |  |
Settlements | 0 |  |
Interest | (36) |  |
Contributions by plan participants | 0 |  |
Benefits paid | 34 |  |
Experience gains | 63 |  |
Actuarial losses to equity accounted units | (92) |  |
Changes in demographic assumptions gain/(loss) | 26 |  |
Arrangements divested | 0 |  |
Currency exchange rate (loss)/gain | (17) |  |
Ending balance | $ (899) | $ (871) |

X
- Definition The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in demographic assumptions that result in remeasurements of the net defined benefit liability (asset). Demographic assumptions deal with matters such as: (a) mortality; (b) rates of employee turnover, disability and early retirement; (c) the proportion of plan members with dependants who will be eligible for benefits; (d) the proportion of plan members who will select each form of payment option available under the plan terms; and (e) claim rates under medical plans. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2019-01-01 -Paragraph 141 -Subparagraph c -Clause ii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_141_c_ii&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_ActuarialGainsLossesArisingFromChangesInDemographicAssumptionsNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in financial assumptions that result in remeasurements of the net defined benefit liability (asset). Financial assumptions deal with items such as: (a) the discount rate; (b) benefit levels, excluding any cost of the benefits to be met by employees, and future salary; (c) in the case of medical benefits, future medical costs, including claim handling costs (ie the costs that will be incurred in processing and resolving claims, including legal and adjuster's fees); and (d) taxes payable by the plan on contributions relating to service before the reporting date or on benefits resulting from that service. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2019-01-01 -Paragraph 141 -Subparagraph c -Clause iii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_141_c_iii&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_ActuarialGainsLossesArisingFromChangesInFinancialAssumptionsNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from experience adjustments that result in remeasurements of the net defined benefit liability (asset). Experience adjustments deal with the effects of differences between the previous actuarial assumptions and what has actually occurred. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2019-01-01 -Paragraph 141 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_141_c&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_ActuarialGainsLossesArisingFromExperienceAdjustmentsNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of benefits paid or payable for retirement benefit plans. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 26 -IssueDate 2019-01-01 -Paragraph 35 -Subparagraph b -Clause v -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=26&code=ifrs-tx-2019-en-r&anchor=para_35_b_v&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_BenefitsPaidOrPayable
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | ifrs-full_ChangesInNetDefinedBenefitLiabilityAssetAbstract
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The decrease (increase) in the net defined benefit liability (asset) resulting from contributions to a defined benefit plan by plan participants. [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 2019-01-01 -Paragraph 141 -Subparagraph f -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_141_f&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_ContributionsToPlanByPlanParticipantsNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from employee service in the current period. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2019-01-01 -Paragraph 141 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_141_a&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_CurrentServiceCostNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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 decrease (increase) in the net defined benefit liability (asset) resulting from settlements. Settlements are transactions that eliminate all further legal or constructive obligations for part or all of the benefits provided under a defined benefit plan, other than a payment of benefits to, or on behalf of, employees that is set out in the terms of the plan and included in the actuarial assumptions. [Refer: Net defined benefit liability (asset); Defined benefit plans [member]; Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2019-01-01 -Paragraph 141 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_141_d&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_GainsLossesArisingFromSettlementsNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from changes in foreign exchange rates. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2019-01-01 -Paragraph 141 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_141_e&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_IncreaseDecreaseThroughChangesInForeignExchangeRatesNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from the passage of time. [Refer: Interest expense; Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2019-01-01 -Paragraph 141 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_141_b&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_InterestExpenseIncomeNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of deficit or surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2019-01-01 -Paragraph 140 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_140_a&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_LiabilityAssetOfDefinedBenefitPlans
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from past service cost. Past service cost is the change in the present value of the defined benefit obligation for employee service in prior periods, resulting from a plan amendment (the introduction or withdrawal of, or changes to, a defined benefit plan) or a curtailment (a significant reduction by the entity in the number of employees covered by a plan). [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 2019-01-01 -Paragraph 141 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_141_d&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_PastServiceCostNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Gains (losses) arising from curtailments net defined benefit liability (asset) + References No definition available. + Details
Name: | rio_GainsLossesArisingFromCurtailmentsNetDefinedBenefitLiabilityAsset
Namespace Prefix: | rio_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Liability asset of defined benefit plans arrangements divested. + References No definition available. + Details
Name: | rio_LiabilityAssetOfDefinedBenefitPlansArrangementsDivested
Namespace Prefix: | rio_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | ifrs-full_CharacteristicsOfDefinedBenefitPlansAxis=ifrs-full_PensionDefinedBenefitPlansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_CharacteristicsOfDefinedBenefitPlansAxis=rio_OtherDefinedBenefitPlansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_NetDefinedBenefitLiabilityAssetAxis=ifrs-full_PresentValueOfDefinedBenefitObligationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |