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Commitments and Contingencies Environmental Requirements - Water and Waste (Details) $ in Millions | Jun. 30, 2022 USD ($) Plant Period
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Federal Coal Ash Regulation |
Site Contingency [Line Items] |
Number of sites where regulated ash units will still be in operation at a specified date | Period | 8
Federal Coal Ash Regulation | PSCo |
Site Contingency [Line Items] |
Number of sites where statistically significant increases over established groundwater standards exist | Period | 4
Number of sites where corrective action options are being evaluated for locations with statistically significant increases above background concentrations | 2
Estimated cost to remediate groundwater sampling results | $ 35
Estimated cost of construction of an alternative collection and treatment system | 25
EPA Penalty | 1
Federal Coal Ash Regulation | PSCo | Minimum [Member] |
Site Contingency [Line Items] |
Cost of Beneficial Use Coal Ash Project | 30
Federal Coal Ash Regulation | PSCo | Maximum [Member] |
Site Contingency [Line Items] |
Cost of Beneficial Use Coal Ash Project | 40
Federal Clean Water Act Section 316 (b) | Capital Addition Purchase Commitments |
Site Contingency [Line Items] |
Liability for estimated cost to comply with regulation | $ 40
Federal Clean Water Act Section 316 (b) | NSP-Minnesota |
Site Contingency [Line Items] |
Minimum number of plants which could be required to make improvements to reduce entrainment | Plant | 6
Federal Clean Water Act Section 316 (b) | NSP-Wisconsin |
Site Contingency [Line Items] |
Minimum number of plants which could be required to make improvements to reduce entrainment | Plant | 2

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