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Asset Impairment Charges - Narrative (Details) $ in Millions, $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2022 CAD ($) MW | Mar. 31, 2021 CAD ($) | Dec. 31, 2022 CAD ($) asset numberOfAssets facility MW | Dec. 31, 2021 CAD ($) MW | Dec. 31, 2020 CAD ($) | Dec. 31, 2020 USD ($)
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Impairment charges |  |  | $ 0 | $ 10 |  |
Recoverable amounts | $ 10,741 |  | 10,741 | 9,226 |  |
Asset impairment charges |  |  | 9 | 648 | $ 84 |
Estimated salvage value |  |  |  | 33 |  |
Reversal of impairment loss |  |  | $ 102 | 0 |  |
Energy Transition |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Asset impairment charges |  |  |  | $ 191 |  |
Discount rate, measurement input |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Discount rates |  |  |  | 5.0 |  |
Wind Facilities |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Impairment charges |  |  |  | $ 10 |  |
Wind Facilities | Level III | Non-recurring fair value measurement | Investment property |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Recoverable amounts |  |  |  | 65 |  |
Kent Hills Wind L.P. |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Impairment charges |  |  |  | $ 2 |  |
Capacity of facility (in megawatts) | MW | 167 |  | 167 | 167 |  |
Keephills Unit 1 | Energy Transition |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Asset impairment charges |  |  |  | $ 94 |  |
Sundance Unit 4 | Energy Transition |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Asset impairment charges |  |  |  | 56 |  |
Kaybob Cogeneration Project | Corporate |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Impairment charges |  | $ 27 |  |  |  |
Asset impairment charges |  |  | $ (2) | 27 | 0 |
Reversal of impairment loss | $ 2 |  |  |  |  |
Hydro |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Number of facilities | facility |  |  | 4 |  |  |
Number of assets | asset |  |  | 2 |  |  |
Asset impairment charges |  |  | $ 21 | 5 | 2 |
Hydro | Hydro Facilities |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Number of assets | numberOfAssets |  |  | 4 |  |  |
Carrying value | 88 |  | $ 88 |  |  |
Hydro | Hydro Facilities | Level III | Non-recurring fair value measurement |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Recoverable amounts | 89 |  | $ 89 |  |  |
Wind |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Number of facilities | facility |  |  | 5 |  |  |
Solar |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Number of facilities | facility |  |  | 1 |  |  |
Wind and Solar |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Asset impairment charges |  |  | $ 43 | 12 | 0 |
Wind and Solar | Wind and Solar Facilities |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Number of assets | asset |  |  | 6 |  |  |
Carrying value | 748 |  | $ 748 |  |  |
Wind and Solar | Wind and Solar Facilities | Level III | Non-recurring fair value measurement |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Recoverable amounts | $ 754 |  | $ 754 |  |  |
Mining assets | Highvale Mine |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Impairment charges |  |  |  | $ 195 |  |
Property, plant and equipment | Sundance Unit 4 |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Impairment charges |  |  |  |  | 70 |
Land |  |  |  |  |  |
Disclosure of impairment loss recognised or reversed [line items] |  |  |  |  |  |
Impairment loss |  |  |  |  | $ 9 | $ 7

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