Other long-term obligations - Summary of Obligations (Detail) - CAD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Other Liabilities Disclosure [Abstract]
Employee retirement benefits	$ 902	$ 1,362
Asset retirement obligations and other environmental liabilities	2,150	1,713
Share-based incentive compensation liabilities (note 7)	101	79
Operating lease liability (note 13)	151	147
Other obligations	163	596
Total other long-term obligations	$ 3,467	$ 3,897

Asset retirement obligation and other environmental liabilities, noncurrent.

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Aggregate carrying value as of the balance sheet date of the liabilities for stock option plans and other equity-based compensation arrangements payable after one year (or the operating cycle, if longer).

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Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent.

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Amount of liabilities classified as other, due after one year or the normal operating cycle, if longer.

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Obligations not otherwise itemized or categorized in the footnotes to the financial statements that are expected to be paid after one year (or the normal operating cycle, if longer), from the balance sheet date.

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Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as noncurrent.

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