Goodwill and Other Intangible Assets - Changes (Details) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Changes in goodwill and other intangible assets
Beginning balance	$ 3,528	$ 3,586
Additions	55	22
Amortization	(80)	(80)
Ending balance	3,503	3,528
Other intangibles
Changes in goodwill and other intangible assets
Beginning balance	636	694
Additions	55	22
Amortization	(80)	(80)
Ending balance	611	636
Oil Sands \| Goodwill
Changes in goodwill and other intangible assets
Beginning balance	2,752	2,752
Ending balance	2,752	2,752
Refining and Marketing \| Goodwill
Changes in goodwill and other intangible assets
Beginning balance	140	140
Ending balance	$ 140	$ 140

The amount of additions to intangible assets other than goodwill, other than those acquired through business combinations. [Refer: Total for all business combinations [member]; Intangible assets other than goodwill]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 38
-IssueDate 2024-01-01
-Paragraph 118
-Subparagraph e
-Clause i
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2024-en-r&anchor=para_118_e_i&doctype=Standard
-URIDate 2024-03-27

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- Definition

The amount of amortisation of intangible assets other than goodwill. [Refer: Depreciation and amortisation expense; Intangible assets other than goodwill]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 38
-IssueDate 2024-01-01
-Paragraph 118
-Subparagraph e
-Clause vi
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2024-en-r&anchor=para_118_e_vi&doctype=Standard
-URIDate 2024-03-27

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The amount of intangible assets and goodwill held by the entity. [Refer: Goodwill; Intangible assets other than goodwill]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 55
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_55&doctype=Standard
-URIDate 2024-03-27

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