- Contract Liabilities (Details) - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Contract with Customer, Liability [Abstract]
Opening balance	$ 146	$ 2
Revenue recognized that was included in the contract liability balance at the beginning of the period	(100)	(2)
Increase due to consideration received, net of revenue recognized during the period	15	146
Closing balance	$ 61	$ 146