Property sale (Details) $ in Millions, $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2021 CAD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2021 CAD ($)
Discontinued Operations and Disposal Groups [Abstract]
Consideration, sale of assets	$ 103
Cash proceeds from sale of assets	61
Consideration received, property	33
Consideration received, permanent easement assets	9
Gain on sale of assets	50	$ 38
Deferred gain on sale of assets	$ 53
Recognition of deferred gain			$ 13