Accounts payable and accrued liabilities (Details) - CAD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Trade payables	$ 768	$ 680
Accrued charges	732	667
Income and other taxes payable	379	255
Dividends payable	177	177
Accrued interest	167	162
Stock-based compensation liabilities	58	50
Payroll-related accruals	151	115
Operating lease liabilities (Note 19)	112	102
Accrued vacation	99	99
Personal injury and other claims provision(1)	78	69
Financial derivative liability (Note 17)	0	60
Other(1)	121	131
Total accounts payable and accrued liabilities	$ 2,842	$ 2,567