Goodwill and Intangible Assets (Details) - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Goodwill
Opening balance	$ 194	$ 194
Additions	142	10
Foreign exchange impact	(7)	(10)
Ending balance	329	194
Intangible assets
Cost, Opening balance	27	22
Accumulated amortization, Opening balance	(15)	(14)
Net carrying amount, Opening balance	12	8
Additions	31	5
Amortization	(3)	(1)
Foreign exchange impact	(3)
Cost, Ending balance	55	27
Accumulated amortization, Ending balance	(18)	(15)
Net carrying amount, Ending balance	37	12
Opening Balance	206	202
Additions	173	15
Amortization	(3)	(1)
Foreign exchange impact	(10)	(10)
Ending Balance	$ 366	$ 206