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Defined Benefit Obligation and Other Long-Term Liabilities - Narrative (Details) $ in Millions, $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 CAD ($) | Dec. 31, 2023 USD ($) | Dec. 31, 2022 CAD ($) | Dec. 01, 2022 CAD ($)
Disclosure of fair value measurement of liabilities [line items] |  |  |  |
Increase (decrease) in defined benefit obligation | $ 5 |  |  |
Defined benefit obligation | 155 |  | $ 150 |
Voluntary contribution | $ 4 | $ 3 | 35 |
Increase in discount rates | 100.00% |  |  |
Level II | Recurring fair value measurement |  |  |  |
Disclosure of fair value measurement of liabilities [line items] |  |  |  |
Commodity risk management assets and liabilities | $ (244) |  | $ 173 |
Level II | Recurring fair value measurement | retail power contract liabilities |  |  |  |
Disclosure of fair value measurement of liabilities [line items] |  |  |  |
Commodity risk management assets and liabilities |  |  |  | $ 129
Risk management assets | Level II | Recurring fair value measurement |  |  |  |
Disclosure of fair value measurement of liabilities [line items] |  |  |  |
Commodity risk management assets and liabilities |  |  |  | $ 139
Pro Forma |  |  |  |
Disclosure of fair value measurement of liabilities [line items] |  |  |  |
Increase (decrease) in defined benefit obligation | $ 40 |  |  |

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- Definition The increase (decrease) in the net defined benefit liability (asset). [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2023-01-01 -Paragraph 141 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2023-en-r&anchor=para_141&doctype=Standard -URIDate 2023-03-23 + Details
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- Definition The amount of risk exposure associated with financial instruments with a shared characteristic that identifies a concentration of risks. [Refer: Financial instruments, class [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 7 -IssueDate 2023-01-01 -Paragraph B8 -Subparagraph c -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2023-en-r&anchor=para_B8_c&doctype=Appendix&subtype=B -URIDate 2023-03-23 + Details
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- Definition Voluntary Contribution + References No definition available. + Details
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