Revenues - Contract Liabilities (Details) - CAD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Contract with Customer, Liability [Abstract]
Opening balance	$ 67	$ 61
Revenue recognized that was included in the contract liability balance at the beginning of the period	(7)	(11)
Increase due to consideration received, net of revenue recognized during the period	7	64
Closing balance	$ 67	$ 114