Financing costs (Detail) - CAD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Financing costs and additional notes and loans payable information [Abstract]
Debt-related interest		$ 52	$ 46
Capitalized interest		(41)	(30)
Net interest expense		11	16
Other interest		1	0
Total financing	[1]	$ 12	$ 16

[1] (d) Amounts to related parties included in financing.44 39