Average demand measured for a specified customer, measured in MW.

No definition available.

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- Definition

The length of notice required to terminate a contract (in years).

+ References

No definition available.

+ Details

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- Definition

Number of Customers

+ References

No definition available.

+ Details

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- Definition

Percentage of public utility's approved equity to capital, including debt and equity.

+ References

No definition available.

+ Details

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- Definition

Amount of public utility's approved rate increase (decrease) by regulatory agency.

+ References

No definition available.

+ Details

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- Definition

Percentage of public utility's approved return on equity.

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Amount of public utility's interim rate increase (decrease) allowed while waiting final decision of regulatory agency.

+ References

No definition available.

+ Details

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- Definition

Percentage of public utility's requested equity to capital, including debt and equity.

+ References

No definition available.

+ Details

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- Definition

Amount of public utility's requested rate increase (decrease) with regulatory agency.

+ References

No definition available.

+ Details

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- Definition

Percentage of public utility's requested rate increase (decrease) with regulatory agency.

+ References

No definition available.

+ Details

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- Definition

Percentage of public utility's requested return on equity.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
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- Definition

The amount of regulated other operating revenues recognized during the period.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Details

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- Details

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- Details

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- Details

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Regulatory Matters - Electric Rates (Details) $ in Millions			12 Months Ended
Regulatory Matters - Electric Rates (Details) $ in Millions	Nov. 01, 2019 USD ($)	Dec. 20, 2018	Dec. 31, 2019 USD ($) Customers Years MW	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
PSCW [Member] \| 2018 Wisconsin General Rate Case [Member] \| SWL&P [Member] \| Retail Customers [Member]
Regulatory Matters [Line Items]
Approved Return on Common Equity		10.40%
Approved Equity Ratio		55.00%
Approved Rate Increase - Amount			$ 3.0
Electric Rates [Member] \| MPUC [Member] \| Minnesota Cost Recovery Riders [Member] \| Minnesota Power [Member] \| Retail Customers [Member]
Regulatory Matters [Line Items]
Revenue from Cost Recovery Riders			$ 31.8	$ 103.8	$ 96.9
Electric Rates [Member] \| MPUC [Member] \| 2016 Minnesota General Rate Case [Member] \| Minnesota Power [Member] \| Retail Customers [Member]
Regulatory Matters [Line Items]
Approved Return on Common Equity				9.25%
Approved Equity Ratio				53.81%
Electric Rates [Member] \| MPUC [Member] \| 2020 Minnesota General Rate Review [Member] \| Minnesota Power [Member] \| Retail Customers [Member]
Regulatory Matters [Line Items]
Requested Average Rate Increase	10.60%
Requested Return on Equity	10.05%
Requested Equity Ratio	53.81%
Annual Additional Revenue Generated from Requested Final Rate Increase	$ 66.0
Public Utilities, Interim Rate Increase (Decrease), Amount	$ 36.1
Electric Rates [Member] \| MPUC [Member] \| Renewable Cost Recovery Rider [Member] \| Minnesota Power [Member] \| Retail Customers [Member]
Regulatory Matters [Line Items]
Approved Rate Increase - Amount				$ 13.0
Electric Rates [Member] \| FERC [Member] \| FERC-Approved Wholesale Rates [Member] \| Minnesota Power [Member] \| Municipal Customers [Member]
Regulatory Matters [Line Items]
Number of Customers \| Customers			15
Notice Required to Terminate (Years) \| Years			3
Electric Rates [Member] \| FERC [Member] \| FERC-Approved Wholesale Rates [Member] \| Minnesota Power [Member] \| Municipal Customers [Member] \| Wholesale Electric Contract (Cost-Based Formula Methodology for Entire Term) [Member]
Regulatory Matters [Line Items]
Number of Customers \| Customers			2
Electric Rates [Member] \| FERC [Member] \| FERC-Approved Wholesale Rates [Member] \| Minnesota Power [Member] \| Municipal Customers [Member] \| Wholesale Electric Contracts (expire December 2024) [Member]
Regulatory Matters [Line Items]
Number of Customers \| Customers			14
Electric Rates [Member] \| FERC [Member] \| FERC-Approved Wholesale Rates [Member] \| Minnesota Power [Member] \| Municipal Customers [Member] \| Wholesale Electric Contract (Termination Effective June 2019) [Member]
Regulatory Matters [Line Items]
Average Customer Demand (MW) \| MW			29