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Regulatory Assets and Liabilities - Other Electric Utilities (Narrative) (Details) $ in Millions, $ in Millions |  | 1 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
May 06, 2024 MW | Sep. 30, 2022 USD ($) | Dec. 31, 2024 CAD ($) | Dec. 31, 2023 CAD ($) | Jul. 18, 2024 USD ($)
Public Utilities, General Disclosures [Line Items] |  |  |  |  |
Regulatory liabilities |  |  | $ 1,880 | $ 1,772 |
Barbados Light and Power Company Limited |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |
Approved regulated return on equity |  |  | 10.00% | 10.00% |
Barbados Light and Power Company Limited | Fair Trading Commission |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |
Approved regulated return on equity |  | 11.75% |  |  |
Allowed equity capital structure |  | 55.00% |  |  |
Deferred Tax Liabilities, Regulatory Assets and Liabilities |  |  |  |  | $ 5
Public Utilities, Interim Rate Increase (Decrease), Amount |  | $ 1 |  |  |
Regulatory liabilities |  | $ 71 |  |  |
New corporate income tax rate |  |  | 9.00% |  |
Approved capacity for recovery of battery storage | MW | 15 |  |  |  |
GBPC | Electric Transmission |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |
Approved regulated return on equity |  |  | 8.52% | 8.32% |

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