REVENUE - Narrative (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2024 CAD ($)	Sep. 30, 2024 CAD ($)
Revenue from Contract with Customer [Abstract]
Revenue recognized	$ 62	$ 295
Increase in contract with customers, liability	201	467
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	57,700	57,700
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 2,100	$ 2,100
Remaining performance obligation, period	3 months	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 8,400	$ 8,400
Remaining performance obligation, period	1 year	1 year