Other expense (Details) - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Other expense [Line Items]
Foreign exchange gain on debt and lease liabilities	$ 0	$ 0	$ (7)
Acquisition-related costs (Note 11)	190
Other expense	52	17	237
Other Expense
Other expense [Line Items]
Foreign exchange gain on debt and lease liabilities	0	0	(7)
Other foreign exchange gains	(12)	0	(4)
Acquisition-related costs (Note 11)	6	0	247
Other	19	17	1
Forward Contracts | Other Expense
Other expense [Line Items]
Other foreign exchange gains	$ 39	$ 0	$ 0