Other long-term liabilities (Details) - CAD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Other Liabilities Disclosure [Abstract]
Operating lease liabilities, net of current portion	$ 202	$ 224
Stock-based compensation liabilities, net of current portion	125	125
Provision for environmental remediation, net of current portion	71	68
Deferred revenue, net of current portion	39	47
Deferred real estate lease and license revenue	15	14
Other, net of current portion	68	64
Other long-term liabilities	$ 520	$ 542
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]	Other long-term liabilities	Other long-term liabilities