Transactions with related parties - Narrative (Detail) - CAD ($) $ in Millions		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
Amounts of sales by Imperial	[1]	$ 17,042	$ 8,777	$ 5,107
Financing costs	[2]	78	28	$ 61
Long-Term Loans
Related Party Transaction [Line Items]
Outstanding loans from an affiliate		3,447	4,447
Exxon Mobil
Related Party Transaction [Line Items]
Amounts of purchases by Imperial		3,719	2,669
Amounts of sales by Imperial		17,042	8,777
Financing costs		$ 78	$ 28

[1] (a) Amounts from related parties included in revenues, (note 16).17,042 8,777 5,107 

[2] (d) Amounts to related parties included in financing, (note 16).782861