Right-of-Use Assets and Leases - ROU assets by asset class (Details) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Changes in ROU assets:
Beginning balance	$ 3,668
Ending balance	4,178	$ 3,668
Cost
Changes in ROU assets:
Beginning balance	5,206	4,248
Additions and adjustments	963	423
Acquisition		1,425
Disposals	(54)	(176)
Divestures		(707)
Foreign exchange	28	(7)
Ending balance	6,143	5,206
Accumulated provision
Changes in ROU assets:
Beginning balance	(1,538)	(1,372)
Depreciation	(444)	(358)
Disposals	32	94
Divestures		96
Foreign exchange	15	2
Ending balance	$ (1,965)	$ (1,538)

The increase in right-of-use assets resulting from acquisitions through business combinations. [Refer: Total for all business combinations [member]; Right-of-use assets]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 16
-IssueDate 2024-01-01
-Paragraph 73
-Subparagraph e
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=16&code=ifrs-tx-2024-en-r&anchor=para_73_e&doctype=Standard
-URIDate 2024-03-27

+ Details

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

- Definition

The amount of additions to right-of-use assets other than those acquired through business combinations. [Refer: Total for all business combinations [member]; Right-of-use assets]

+ References

+ Details

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

- Definition

The amount of depreciation of right-of-use assets. [Refer: Depreciation and amortisation expense; Right-of-use assets]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2024-01-01
-Paragraph 53
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2024-en-r&anchor=para_53_a&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_DepreciationRightofuseAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

The decrease in right-of-use assets resulting from disposals. [Refer: Right-of-use assets]

+ References

+ Details

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

- Definition

The increase (decrease) in right-of-use assets resulting from net exchange differences arising on the translation of the financial statements from the functional currency into a different presentation currency, including the translation of a foreign operation into the presentation currency of the reporting entity. [Refer: Right-of-use assets]

+ References

+ Details

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

- References

No definition available.

+ Details

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

- Definition

The amount of assets that represent a lessee's right to use an underlying asset for the lease term that do not meet the definition of investment property. Underlying asset is an asset that is the subject of a lease, for which the right to use that asset has been provided by a lessor to a lessee.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2024-01-01
-Paragraph 53
-Subparagraph j
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2024-en-r&anchor=para_53_j&doctype=Standard
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2024-01-01
-Paragraph 47
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2024-en-r&anchor=para_47_a&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_RightofuseAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The decrease in right of use assets resulting from the loss of control of a subsidiary.

+ References

No definition available.

+ Details

Name:	su_DecreaseThroughLossOfControlOfSubsidiaryRightOfUseAssets
Namespace Prefix:	su_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis=ifrs-full_GrossCarryingAmountMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis=ifrs-full_AccumulatedDepreciationAmortisationAndImpairmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: