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Derivatives Instruments (Notional Volumes of Outstanding Derivatives Designated for Regulatory Deferral) (Details) $ in Millions | 12 Months Ended
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Dec. 31, 2024 CAD ($) MMBTU MWh T
Commodity swaps and forwards | Coal | 2025 |
Derivative [Line Items] |
Coal (metric tonnes) | T | 1
Commodity swaps and forwards | Coal | 2026-2027 |
Derivative [Line Items] |
Coal (metric tonnes) | T | 0
Commodity swaps and forwards | Natural gas | 2025 |
Derivative [Line Items] |
Natural Gas (Mmbtu) / Power (MWh) | MWh | 21
Commodity swaps and forwards | Natural gas | 2026-2027 |
Derivative [Line Items] |
Natural Gas (Mmbtu) / Power (MWh) | MWh | 23
Commodity swaps and forwards | Power | 2025 |
Derivative [Line Items] |
Natural Gas (Mmbtu) / Power (MWh) | MWh | MWh | 1
Commodity swaps and forwards | Power | 2026-2027 |
Derivative [Line Items] |
Natural Gas (Mmbtu) / Power (MWh) | MWh | MWh | 0
Physical natural gas purchases | Natural gas | 2025 |
Derivative [Line Items] |
Natural Gas (Mmbtu) / Power (MWh) | MWh | 6
Physical natural gas purchases | Natural gas | 2026-2027 |
Derivative [Line Items] |
Natural Gas (Mmbtu) / Power (MWh) | MWh | 0
Foreign Exchange Swaps and Forward Contracts | 2025 |
Derivative [Line Items] |
Notional volumes of outstanding derivatives designated as cash flow hedges that are expected to settle | $ | $ 208
Weighted average rate | 1.3361
% of USD requirements | 50.00%
Foreign Exchange Swaps and Forward Contracts | 2026-2027 |
Derivative [Line Items] |
Notional volumes of outstanding derivatives designated as cash flow hedges that are expected to settle | $ | $ 69
Weighted average rate | 1.3296
% of USD requirements | 17.00%

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