REVENUES - Narrative (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2023 CAD ($)	Sep. 30, 2023 CAD ($)
Revenue from Contract with Customer [Abstract]
Revenue recognized	$ 90	$ 179
Increase in contract with customers, liability	213	380
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	57,500	57,500
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 2,000	$ 2,000
Remaining performance obligation, period	3 months	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 6,600	$ 6,600
Remaining performance obligation, period	1 year	1 year