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Financial Instruments Sensitivity ranges for the base fair values (Details) number in Millions, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 CAD ($) | Dec. 31, 2018 CAD ($)
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Base fair value | $ 3,104 | $ 3,234
Long-term power sale – US | Long-term contracts |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Base fair value | 737 | 801
Unit contingent power purchases |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Base fair value | (6) | 18
Structured products – Eastern US |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Base fair value | 7 | 6
Full requirements – Eastern US |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Base fair value | 10 | 0
Long-term wind energy sale – Eastern US |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Base fair value | (28) | (39)
Others |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Base fair value | $ 0 | $ 9
Maximum | Long-term power sale – US | Long-term contracts |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Sensitivity ranges for the base fair value, reasonably possible change in risk assumption, financial instruments | (46) | (116)
Maximum | Unit contingent power purchases |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Sensitivity ranges for the base fair value, reasonably possible change in risk assumption, financial instruments | (1) | (4)
Maximum | Structured products – Eastern US |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Sensitivity ranges for the base fair value, reasonably possible change in risk assumption, financial instruments | (2) | (5)
Maximum | Full requirements – Eastern US |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Sensitivity ranges for the base fair value, reasonably possible change in risk assumption, financial instruments | (3) | 0
Maximum | Long-term wind energy sale – Eastern US |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Sensitivity ranges for the base fair value, reasonably possible change in risk assumption, financial instruments | (20) | (21)
Maximum | Others |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Sensitivity ranges for the base fair value, reasonably possible change in risk assumption, financial instruments | (7) | (3)
Minimum | Long-term power sale – US | Long-term contracts |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Sensitivity ranges for the base fair value, reasonably possible change in risk assumption, financial instruments | 139 | 116
Minimum | Unit contingent power purchases |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Sensitivity ranges for the base fair value, reasonably possible change in risk assumption, financial instruments | 1 | 4
Minimum | Structured products – Eastern US |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Sensitivity ranges for the base fair value, reasonably possible change in risk assumption, financial instruments | 2 | 5
Minimum | Full requirements – Eastern US |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Sensitivity ranges for the base fair value, reasonably possible change in risk assumption, financial instruments | 3 | 0
Minimum | Long-term wind energy sale – Eastern US |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Sensitivity ranges for the base fair value, reasonably possible change in risk assumption, financial instruments | 20 | 21
Minimum | Others |  |
Disclosure of sensitivity analysis for actuarial assumptions [line items] |  |
Sensitivity ranges for the base fair value, reasonably possible change in risk assumption, financial instruments | 7 | 3

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