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Commitments, Guarantees and Contingencies - Transmission (Details) $ in Millions | Dec. 31, 2018 USD ($) kV Miles MW
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Great Northern Transmission Line [Member] |
Transmission [Line Items] |
Total Project Costs Incurred to Date | $ 380.8
Great Northern Transmission Line [Member] | Minimum [Member] |
Transmission [Line Items] |
Total Project Cost in the U.S. | 560.0
Great Northern Transmission Line [Member] | Maximum [Member] |
Transmission [Line Items] |
Total Project Cost in the U.S. | 710.0
Manitoba Hydro [Member] | Great Northern Transmission Line [Member] |
Transmission [Line Items] |
Project Costs Recovered from Counterparty | $ 203.7
Minnesota Power [Member] | Great Northern Transmission Line [Member] |
Transmission [Line Items] |
Transmission Line Length (Miles) | Miles | 220
Transmission Line Capacity (kV) | kV | 500
Minnesota Power [Member] | Great Northern Transmission Line [Member] | Minimum [Member] |
Transmission [Line Items] |
Total Project Cost in the U.S. | $ 300.0
Minnesota Power [Member] | Great Northern Transmission Line [Member] | Maximum [Member] |
Transmission [Line Items] |
Total Project Cost in the U.S. | $ 350.0
Manitoba Hydro PPA [Member] | Manitoba Hydro [Member] |
Transmission [Line Items] |
Output Being Purchased (MW) | MW | 250

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