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Risk Management Activities - Commodity Risk Management (Details) - Commodity risk management t in Thousands, kJ in Billions | Dec. 31, 2018 MWh kJ t | Dec. 31, 2017 MWh kJ t
--- | --- | ---
Electricity | Cash flow hedges |  |
Disclosure of detailed information about hedges [line items] |  |
Notional amount sold | 2,128,000 | 1,997,000
Notional amount purchased | 0 | 44,000
Electricity | Non-Hedges |  |
Disclosure of detailed information about hedges [line items] |  |
Notional amount sold | 58,885,000 | 14,688,000
Notional amount purchased | 37,023,000 | 7,348,000
Natural gas | Non-Hedges |  |
Disclosure of detailed information about hedges [line items] |  |
Notional amount sold | kJ | 80,413 | 74,194
Notional amount purchased | kJ | 110,488 | 103,805
Transmission | Non-Hedges |  |
Disclosure of detailed information about hedges [line items] |  |
Notional amount sold | 29,000 | 1,000
Notional amount purchased | 11,163,000 | 3,455,000
Emissions | Non-Hedges |  |
Disclosure of detailed information about hedges [line items] |  |
Derivative, Nonmonetary Notional Amount Sold, Emissions | t | 3,134 | 516
Derivative, Nonmonetary Notional Amount Purchased, Emissions | t | 2,948 | 717

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- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table. + References No definition available. + Details
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- Details
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- Details
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- Details
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- Details
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- Details
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- Details
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- Details
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