REVENUE - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2022 CAD ($)
Revenue from Contract with Customer [Abstract]
Revenue recognized	$ 61
Increase in contract with customers, liability	97
Remaining performance obligation	58,300
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-04-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 5,500
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, period	9 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 6,100
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, period	1 year