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Commodity Derivatives (Details) MWh in Millions, MMBTU in Millions, $ in Millions | Sep. 30, 2020 USD ($) MWh MMBTU | Dec. 31, 2019 MMBTU MWh
--- | --- | ---
Cash Flow Hedge Commodity [Member] |  |  |
Derivative [Line Items] |  |  |
Commodity contracts designated as cash flow hedges | $ |  | $ 0 |
Electric Commodity [Member] |  |  |
Gross Notional Amounts of Commodity Forwards, Options and FTRs [Abstract] |  |  |
Derivative, Nonmonetary Notional Amount | MWh | [1],[2] | 107 | 95
Natural Gas Commodity |  |  |
Gross Notional Amounts of Commodity Forwards, Options and FTRs [Abstract] |  |  |
Derivative, Nonmonetary Notional Amount | MMBTU | [1],[2] | 177 | 110
[1] | Not reflective of net positions in the underlying commodities.
[2] | Notional amounts for options included on a gross basis but weighted for the probability of exercise.

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