Intangible assets - Schedule of Finite-Lived Intangible Assets (Details) - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cost
Beginning balance	$ 66	$ 64
Additions (Note 11)	3,022
Foreign exchange impact	(27)	2
Ending balance	3,061	66
Accumulated amortization
Beginning balance	(24)	(21)
Amortization	(61)	(3)
Foreign exchange impact	(2)	0
Ending balance	(87)	(24)
Net carrying amount
Beginning balance	42	43
Additions (Note 11)	3,022
Amortization	(61)	(3)
Foreign exchange impact	(29)	2
Ending balance	2,974	42
Indefinite-lived intangible assets	$ 1,798	$ 9