XML 129 R103.htm IDEA: XBRL DOCUMENT
v3.20.4

PENSIONS AND OTHER POST RETIREMENT BENEFITS - Actuarial assumptions (Details) - CAD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 | Dec. 31, 2019
Pension and other PostRetirement Benefits, |  |
Actual experience period | 5 years |
Increase in actuarial assumption (as a percent) | 1.00% |
Decrease in actuarial assumption (as a percent) | 1.00% |
2021 - 2023 |  |
Pension and other PostRetirement Benefits, |  |
Rate of compensation increase | 2.50% |
After 2023 |  |
Pension and other PostRetirement Benefits, |  |
Rate of compensation increase | 3.00% |
Defined benefits pension plans |  |
Pension and other PostRetirement Benefits, |  |
Discount rate | 2.50% | 3.10%
Rate of compensation increase | 3.00% | 3.00%
Defined benefits pension plans | Discount rate |  |
Pension and other PostRetirement Benefits, |  |
Increase (decrease) in interest and service cost due to increase in actuarial assumption | $ (24) |
Increase (decrease) in service and interest cost due to decrease in actuarial assumption | 33 |
Increase (decrease) in net obligation due to increase in actuarial assumption | (1,175) |
Increase (decrease) in net obligation due to decrease in actuarial assumption | $ 1,533 |
Defined benefits other post retirement benefits |  |
Pension and other PostRetirement Benefits, |  |
Discount rate | 2.50% | 3.10%
Rate of compensation increase | 3.00% | 3.00%
Assumption of percentage of increase of healthcare costs | 5.00% |
Increase (decrease) in net obligation due to increase in actuarial assumption | $ (86) |
Increase (decrease) in net obligation due to decrease in actuarial assumption | 108 |
Defined benefits other post retirement benefits | Actuarial assumption of medical cost trend rates |  |
Pension and other PostRetirement Benefits, |  |
Increase (decrease) in interest and service cost due to increase in actuarial assumption | 1 |
Increase (decrease) in service and interest cost due to decrease in actuarial assumption | (1) |
Increase (decrease) in net obligation due to increase in actuarial assumption | 38 |
Increase (decrease) in net obligation due to decrease in actuarial assumption | $ (32) |

X
- Definition The discount rate used as the significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit obligation, at present value; Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2020-01-01 -Paragraph 144 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_144&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_ActuarialAssumptionOfDiscountRates
Namespace Prefix: | ifrs-full_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The expected rate of increases in pension that is used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit plans [member]; Defined benefit obligation, at present value; Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2020-01-01 -Paragraph 144 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_144&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_ActuarialAssumptionOfExpectedRatesOfPensionIncreases
Namespace Prefix: | ifrs-full_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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

X
- Definition The increase (decrease) in a defined benefit obligation that would have been caused by a decrease in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2020-01-01 -Paragraph 145 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_145_a&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_IncreaseDecreaseInDefinedBenefitObligationDueToReasonablyPossibleDecreaseInActuarialAssumption
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The increase (decrease) in a defined benefit obligation that would have been caused by an increase in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2020-01-01 -Paragraph 145 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_145_a&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_IncreaseDecreaseInDefinedBenefitObligationDueToReasonablyPossibleIncreaseInActuarialAssumption
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The reasonably possible percentage of the decrease in the actuarial assumption used to determine the present value of defined benefit obligation. [Refer: Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2020-01-01 -Paragraph 145 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_145_a&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_PercentageOfReasonablyPossibleDecreaseInActuarialAssumption
Namespace Prefix: | ifrs-full_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The reasonably possible percentage of the increase in the actuarial assumption used to determine the present value of defined benefit obligation. [Refer: Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2020-01-01 -Paragraph 145 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2020-en-r&anchor=para_145_a&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_PercentageOfReasonablyPossibleIncreaseInActuarialAssumption
Namespace Prefix: | ifrs-full_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Actual experience period. + References No definition available. + Details
Name: | su_ActualExperiencePeriod
Namespace Prefix: | su_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Medical cost trend rate used as significant actuarial assumption to determine the present value of a defined benefit obligation after year five. + References No definition available. + Details
Name: | su_ActuarialAssumptionOfMedicalCostTrendRatesAfterYearFive
Namespace Prefix: | su_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Increase (decrease) in service and interest cost due to decrease in actuarial assumption. + References No definition available. + Details
Name: | su_IncreaseDecreaseInServiceAndInterestCostDueToDecreaseInActuarialAssumption
Namespace Prefix: | su_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The increase (decrease) in interest and service cost that would have been caused by an increase in a significant actuarial assumption that was reasonably possible at the end of the reporting period. + References No definition available. + Details
Name: | su_IncreaseDecreaseInServiceAndInterestCostDueToIncreaseInActuarialAssumption
Namespace Prefix: | su_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | ifrs-full_MaturityAxis=su_NotLaterThanYearThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=su_LaterThanYearThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_DefinedBenefitPlansAxis=ifrs-full_DefinedBenefitPlansOtherThanMultiemployerPlansStatePlansAndPlansThatShareRisksBetweenEntitiesUnderCommonControlMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ActuarialAssumptionsAxis=ifrs-full_ActuarialAssumptionOfDiscountRatesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_DefinedBenefitPlansAxis=su_DefinedBenefitOtherPostRetirementBenefitsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ActuarialAssumptionsAxis=ifrs-full_ActuarialAssumptionOfMedicalCostTrendRatesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |