Financial instruments (Details) - CAD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Schedule of Investments [Line Items]
Debt and finance lease liabilities, carrying value	$ 19,162		$ 19,651
Debt and finance lease liabilities, fair value	17,845		$ 17,720
Net Investment Hedge
Schedule of Investments [Line Items]
Unrealized gain (loss) on net investment hedge	$ (1)	$ 98

Debt and finance lease liabilities, excluding Commercial paper and Term Loans

No definition available.

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- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5618551-113959

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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- Details

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