Financial Instruments and Risk Management - Non Designated Derivative Financial Instruments (Details) - Non-Designated Derivative Financial Instruments - At fair value - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Financial Instruments and Risk Management
Fair value outstanding, beginning of year	$ (20)	$ (65)
Changes in fair value recognized in earnings during the year	114	25
Cash settlements - paid (received) during the year	(12)	20
Fair value outstanding, end of year	$ 82	$ (20)

The amount of assets less the amount of liabilities.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
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-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
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-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2024-03-27

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