Fair Value of Financial Instruments and Risk Management - Credit Risk Narrative (Details) - CAD ($) $ in Millions |
6 Months Ended | |
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Jun. 30, 2026 |
Dec. 31, 2025 |
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| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Value of derivative instruments in net liability positions | $ 83 | $ 99 |
| Three customers | Revenue | Customer concentration risk | ITC | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Concentration risk percentage | 65.00% |
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- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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