Financial instruments (Fair value of financial instruments) (Details) - CAD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, excluding finance leases, carrying amount	$ 21,201	$ 20,887
Fair Value, Recurring \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, excluding finance leases, fair value	$ 20,246	$ 19,688

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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+ Details

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

+ References

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