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Commitments and Contingencies FERC NOPR on ROE Incentive Adders (Details) - Federal Energy Regulatory Commission (FERC) [Member] - NSP Minnesota, NSP Wisconsin and SPS | Sep. 30, 2021
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Commitments and Contingencies Disclosure [Abstract] |
ROE incentive adders related to FERC NOPR | 0.50%
Public Utilities, General Disclosures [Line Items] |
ROE incentive adders related to FERC NOPR | 0.50%

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- Definition ROE incentive adders related to FERC NOPR + References No definition available. + Details
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