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Risk Management Activities - Hedged Items on the Statement of Financial Position (Details) - CAD ($) $ in Millions	12 Months Ended
	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

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

+ References

No definition available.

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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
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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
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