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Fair Value of Financial Instruments and Risk Management - Credit Risk (Narrative) (Details) - CAD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2024 | Dec. 31, 2023
Fair Value, Concentration Risk, Financial Statement Captions [Line Items] |  |
Value of derivative instruments in net liability positions | $ 117 | $ 117
Revenue | Three customers | Customer Concentration Risk | ITC |  |
Fair Value, Concentration Risk, Financial Statement Captions [Line Items] |  |
Concentration risk percentage | 70.00% |

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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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4H -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-4H + Details
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