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Fair Value of Financial Instruments Fair Value Options Quantitative Disclosure (Details) - USD ($) | Sep. 30, 2019 | Dec. 31, 2018
--- | --- | ---
Low [Member] |  |
Commodity Contracts |  |
Electricity physical forwards | $ 11.57 | $ 14.60
Natural gas financial swaps | 1.23 | 0.95
Financial swaps - electricity | 15.50 |
High [Member] |  |
Commodity Contracts |  |
Electricity physical forwards | 64.41 | 69.00
Natural gas financial swaps | 3.74 | 4.64
Financial swaps - electricity | 53.97 |
Weighted Average [Member] |  |
Commodity Contracts |  |
Electricity physical forwards | 42.98 | 45.00
Natural gas financial swaps | 1.69 | 1.82
Financial swaps - electricity | 36.90 |
Assets [Member] |  |
Commodity Contracts |  |
Electricity physical forwards | 0 | 3,000,000
Natural gas financial swaps | 1,000,000 | 0
Financial swaps - electricity | 1,000,000 |
Total commodity contracts | 2,000,000 | 3,000,000
Liabilities [Member] |  |
Commodity Contracts |  |
Electricity physical forwards | 96,000,000 | 84,000,000
Natural gas financial swaps | 4,000,000 | 7,000,000
Financial swaps - electricity | 3,000,000 |
Total commodity contracts | $ 103,000,000 | $ 91,000,000

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- Definition Fnancial swaps - electricity + References No definition available. + Details
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