XML 101 R71.htm IDEA: XBRL DOCUMENT
v3.8.0.1

OTHER LONG-TERM LIABILITIES - Asset Retirement Obligations (Details) - CAD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Disclosure of other provisions [line items] |  |  |
Asset retirement obligations settlement period | 60 years |  |
Reconciliation Of Changes In Provision For Decommissioning Restoration And Rehabilitation Costs [Roll Forward] |  |  |
Balance – beginning of year | $ 3,243 | $ 2,950 | $ 4,221
Balance – end of year | 4,327 | 3,243 | 2,950
Less: current portion | 92 | 95 | 101
Non-current asset retirement obligation | $ 4,235 | $ 3,148 | $ 2,849
Provision for decommissioning, restoration and rehabilitation costs [member] |  |  |
Disclosure of other provisions [line items] |  |  |
Weighted average discount rate | 4.70% | 5.20% | 5.90%
Reconciliation Of Changes In Provision For Decommissioning Restoration And Rehabilitation Costs [Roll Forward] |  |  |
Liabilities incurred | $ 12 | $ 3 | $ 7
Liabilities acquired, net | 784 | 30 | 129
Liabilities settled | (274) | (267) | (370)
Asset retirement obligation accretion | 164 | 142 | 173
Revision of cost, inflation rates and timing estimates | (40) | (68) | (313)
Change in discount rate | 509 | 493 | (1,150)
Foreign exchange adjustments | $ (71) | $ (40) | $ 253

X
- Definition Decommissioning, Restoration, And Rehabilitation Liabilities, Period Of Accretion + References No definition available. + Details
Name: | cnq_DecommissioningRestorationAndRehabilitationLiabilitiesPeriodOfAccretion
Namespace Prefix: | cnq_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Reconciliation Of Changes In Provision For Decommissioning Restoration And Rehabilitation Costs [Roll Forward] + References No definition available. + Details
Name: | cnq_ReconciliationOfChangesInProvisionForDecommissioningRestorationAndRehabilitationCostsRollForward
Namespace Prefix: | cnq_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted Average Discount Rate Used In Current Measurement Of Provision For Decommissioning, Restoration And Rehabilitation Costs + References No definition available. + Details
Name: | cnq_WeightedAverageDiscountRateUsedInCurrentMeasurementOfProvisionForDecommissioningRestorationAndRehabilitationCosts
Namespace Prefix: | cnq_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The increase in other provisions resulting from acquisitions through business combinations. [Refer: Business combinations [member]; Other provisions] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 37 -IssueDate 2017-01-01 -Paragraph 84 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2017-03-01&anchor=para_84&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_AcquisitionsThroughBusinessCombinationsOtherProvisions
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_DisclosureOfOtherProvisionsLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The increase (decrease) in other provisions resulting from a change in discount rate. [Refer: Other provisions] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 37 -IssueDate 2017-01-01 -Paragraph 84 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2017-03-01&anchor=para_84_e&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_IncreaseDecreaseThroughChangeInDiscountRateOtherProvisions
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The increase (decrease) in other provisions resulting from foreign currency exchange rate changes on provisions measured in a currency different from the entity's presentation currency. [Refer: Other provisions] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 37 -IssueDate 2017-01-01 -Paragraph 84 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2017-03-01&anchor=para_84&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_IncreaseDecreaseThroughNetExchangeDifferencesOtherProvisions
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The increase in other provisions through adjustments arising from the passage of time. [Refer: Other provisions] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 37 -IssueDate 2017-01-01 -Paragraph 84 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2017-03-01&anchor=para_84_e&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_IncreaseDecreaseThroughTimeValueOfMoneyAdjustmentOtherProvisions
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of non-current provision for decommissioning, restoration and rehabilitation costs. [Refer: Provision for decommissioning, restoration and rehabilitation costs] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 37 -IssueDate 2017-01-01 -Section D Examples: disclosures -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2017-03-01&anchor=sect_DExamples:disclosures&doctype=Illustrative%20Examples -URIDate 2017-03-09 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 37 -IssueDate 2017-01-01 -Paragraph 87 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2017-03-01&anchor=para_87&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_LongtermProvisionForDecommissioningRestorationAndRehabilitationCosts
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount recognised for new other provisions. [Refer: Other provisions] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 37 -IssueDate 2017-01-01 -Paragraph 84 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2017-03-01&anchor=para_84_b&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_NewProvisionsOtherProvisions
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of provision for costs related to decommissioning, restoration and rehabilitation. [Refer: Other provisions] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 37 -IssueDate 2017-01-01 -Section D Examples: disclosures -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2017-03-01&anchor=sect_DExamples:disclosures&doctype=Illustrative%20Examples -URIDate 2017-03-09 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 37 -IssueDate 2017-01-01 -Paragraph 87 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2017-03-01&anchor=para_87&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_ProvisionForDecommissioningRestorationAndRehabilitationCosts
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount used (ie incurrent and charged against the provision) for other provisions. [Refer: Other provisions] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 37 -IssueDate 2017-01-01 -Paragraph 84 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2017-03-01&anchor=para_84_c&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_ProvisionUsedOtherProvisions
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of current provision for decommissioning, restoration and rehabilitation costs. [Refer: Provision for decommissioning, restoration and rehabilitation costs] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 37 -IssueDate 2017-01-01 -Section D Examples: disclosures -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2017-03-01&anchor=sect_DExamples:disclosures&doctype=Illustrative%20Examples -URIDate 2017-03-09 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 37 -IssueDate 2017-01-01 -Paragraph 87 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2017-03-01&anchor=para_87&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_ShorttermProvisionForDecommissioningRestorationAndRehabilitationCosts
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount reversed for unused other provisions. [Refer: Other provisions] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 37 -IssueDate 2017-01-01 -Paragraph 84 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2017-03-01&anchor=para_84_d&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_UnusedProvisionReversedOtherProvisions
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | ifrs-full_ClassesOfProvisionsAxis=ifrs-full_ProvisionForDecommissioningRestorationAndRehabilitationCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |