Other Expense - Other Expense (Details) - CAD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Other Income and Expenses [Abstract]
Foreign exchange gain on debt and lease liabilities	$ 0	$ (52)	$ 0	$ (85)
Other foreign exchange gains	0	(3)	(2)	(2)
Acquisition-related costs	0	209	0	212
Other	7	3	8	4
Other income	$ 7	$ 157	$ 6	$ 129