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Risk Management Activities - Hedged Items on the Statement of Financial Position (Details) - CAD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2024 | Dec. 31, 2023
Physical power sales | Cash flow hedges | Commodity risk management |  |
Disclosure of detailed information about hedging instruments [line items] |  |
Gain (loss) on hedge ineffectiveness | $ 114 | $ (114)
Reserve of cash flow hedges | 65 | (129)
Foreign-denominated Debt | Net Investment Hedge | Currency risk |  |
Disclosure of detailed information about hedging instruments [line items] |  |
Gain (loss) on hedge ineffectiveness | 0 | 0
Reserve of cash flow hedges | $ (34) | $ (36)

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- Definition The gain (loss) on hedge ineffectiveness. Hedge ineffectiveness is the extent to which the changes in the fair value or the cash flows of the hedging instrument are greater or less than those on the hedged item. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2024-01-01 -Paragraph 24C -Subparagraph a -Clause i -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2024-en-r&anchor=para_24C_a_i&doctype=Standard -URIDate 2024-03-27 + Details
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- Definition A component of equity representing the accumulated portion of gain (loss) on a hedging instrument that is determined to be an effective hedge for cash flow hedges. [Refer: Cash flow hedges [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 78 -Subparagraph e -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_78_e&doctype=Standard -URIDate 2024-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 9 -IssueDate 2024-01-01 -Paragraph 6.5.11 -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=9&code=ifrs-tx-2024-en-r&anchor=para_6.5.11&doctype=Standard -URIDate 2024-03-27 + Details
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