FINANCIAL INSTRUMENTS - Fair Value Hierarchy for Risk Management Assets and Liabilities Carried at Fair Value (Detail) - CAD ($) $ in Millions |
Sep. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Disclosure Of Levels Of Fair Value Hierarchy [Line Items] | ||
| Fair value of derivative financial instruments net | $ 28 | $ 10 |
| Level 2 of fair value hierarchy | ||
| Disclosure Of Levels Of Fair Value Hierarchy [Line Items] | ||
| Fair value of derivative financial instruments | 20 | (1) |
| Fair value of derivative financial instruments net | 28 | 10 |
| Level 3 of fair value hierarchy | ||
| Disclosure Of Levels Of Fair Value Hierarchy [Line Items] | ||
| Fair value of derivative financial instruments | $ 8 | $ 11 |