Northern States Power 10-Q 31 Jul 20 2020 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2020	Jul. 31, 2020
Cover [Abstract]
Entity Registrant Name	NORTHERN STATES POWER CO /WI/
Entity Central Index Key	0000072909
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Amendment Flag	false
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2020
Document Transition Report	false
Entity Incorporation, State or Country Code	WI
Entity File Number	001-03140
Entity Tax Identification Number	39-0508315
Entity Address, Address Line One	1414 West Hamilton Avenue
Entity Address, City or Town	Eau Claire
Entity Address, State or Province	WI
Entity Address, Postal Zip Code	54701
City Area Code	715
Local Phone Number	839-2625
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		933,000,000

Management's Opinion

Management's Opinion	6 Months Ended
	Jun. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Management's Opinion	In the opinion of management, the accompanying unaudited consolidated financial statements contain all adjustments necessary to present fairly, in accordance with U.S. GAAP, the financial position of NSP-Wisconsin and its subsidiaries as of June 30, 2020 and Dec. 31, 2019; the results of its operations, including the components of net income, changes in stockholder's equity and comprehensive income for the three and six months ended June 30, 2020 and 2019; and its cash flows for the six months ended June 30, 2020 and 2019. All adjustments are of a normal, recurring nature, except as otherwise disclosed. Management has also evaluated the impact of events occurring after June 30, 2020 up to the date of issuance of these consolidated financial statements. These statements contain all necessary adjustments and disclosures resulting from that evaluation. The Dec. 31, 2019 balance sheet information has been derived from the audited 2019 consolidated financial statements included in the NSP-Wisconsin Annual Report on Form 10-K for the year ended Dec. 31, 2019. These notes to the consolidated financial statements have been prepared pursuant to the rules and regulations of the SEC for Quarterly Reports on Form 10-Q. Certain information and note disclosures normally included in financial statements prepared in accordance with GAAP on an annual basis have been condensed or omitted pursuant to such rules and regulations. For further information, refer to the consolidated financial statements and notes thereto, included in the NSP-Wisconsin Annual Report on Form 10-K for the year ended Dec. 31, 2019, filed with the SEC on Feb. 21, 2020. Due to the seasonality of NSP-Wisconsin’s electric and natural gas sales, interim results are not necessarily an appropriate base from which to project annual results.

Accounting Pronouncements

Accounting Pronouncements	6 Months Ended
	Jun. 30, 2020
Accounting Standards Update and Change in Accounting Principle [Abstract]
Accounting Pronouncements	Recently Adopted Credit Losses — In 2016, the FASB issued Financial Instruments - Credit Losses, Topic 326 (ASC Topic 326), which changes how entities account for losses on receivables and certain other assets. The guidance requires use of a current expected credit loss model, which may result in earlier recognition of credit losses than under previous accounting standards.

CONSOLIDATED STATEMENTS OF COMM

CONSOLIDATED STATEMENTS OF COMMON STOCKHOLDER'S EQUITY - USD ($)	Total	Common stock	Additional Paid In Capital	Retained Earnings
Balance (in shares) at Dec. 31, 2018		933,000
Beginning Balance at Dec. 31, 2018	$ 942,400,000	$ 93,300,000	$ 510,100,000	$ 339,000,000
Increase (Decrease) in Stockholder's Equity
Net income	32,600,000
Common dividends declared to parent	(40,300,000)			(40,300,000)
Contribution of capital by parent	3,500,000		3,500,000
Balance (in shares) at Jun. 30, 2019		933,000
Ending Balance at Jun. 30, 2019	938,200,000	$ 93,300,000	513,600,000	331,300,000
Balance (in shares) at Mar. 31, 2019		933,000
Beginning Balance at Mar. 31, 2019	942,000,000	$ 93,300,000	510,100,000	338,600,000
Increase (Decrease) in Stockholder's Equity
Net income	8,600,000
Common dividends declared to parent	(15,900,000)			(15,900,000)
Contribution of capital by parent	3,500,000		3,500,000
Balance (in shares) at Jun. 30, 2019		933,000
Ending Balance at Jun. 30, 2019	$ 938,200,000	$ 93,300,000	513,600,000	331,300,000
Balance (in shares) at Dec. 31, 2019	933,000	933,000
Beginning Balance at Dec. 31, 2019	$ 966,600,000	$ 93,300,000	537,300,000	336,000,000
Increase (Decrease) in Stockholder's Equity
Net income	45,700,000
Common dividends declared to parent	(37,100,000)			(37,100,000)
Contribution of capital by parent	40,400,000		40,400,000
Credit Losses, Topic 326 (ASC Topic 326)	$ (100,000)			(100,000)
Balance (in shares) at Jun. 30, 2020	933,000	933,000
Ending Balance at Jun. 30, 2020	$ 1,015,500,000	$ 93,300,000	577,700,000	344,500,000
Balance (in shares) at Mar. 31, 2020		933,000
Beginning Balance at Mar. 31, 2020	993,200,000	$ 93,300,000	547,300,000	352,600,000
Increase (Decrease) in Stockholder's Equity
Net income	12,100,000
Common dividends declared to parent	(20,200,000)			(20,200,000)
Contribution of capital by parent	$ 30,400,000		30,400,000
Balance (in shares) at Jun. 30, 2020	933,000	933,000
Ending Balance at Jun. 30, 2020	$ 1,015,500,000	$ 93,300,000	$ 577,700,000	$ 344,500,000

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Operating revenues
Electric, non-affiliates	$ 157.8	$ 164.4	$ 328.7	$ 335.3
Electric, affiliates	41.5	43.5	82.4	87.6
Natural gas	19	20.9	64.2	82
Other	0.2	0.1	0.2	0.2
Total operating revenues	218.5	228.9	475.5	505.1
Operating expenses
Electric fuel and purchased power, non-affiliates	3.4	3.1	6.3	5
Purchased power, affiliates	91.3	99.9	185.6	203.4
Cost of natural sold and transported	6.6	8.2	28	40.5
Operating and maintenance expenses	44.9	51.3	93.5	103.2
Conservation program expenses	3.2	3.1	6.3	6
Depreciation and amortization	38.8	34.4	77.4	68.5
Taxes (other than income taxes)	7.1	7.1	14.1	14.7
Total operating expenses	195.3	207.1	411.2	441.3
Operating income	23.2	21.8	64.3	63.8
Other expense, net	(1.8)	(0.3)	(4.3)	(0.6)
Allowance for funds used during construction — equity	1.4	0.9	2.5	1.4
Interest charges and financing costs
Interest charges — includes other financing costs of $0.4, $0.3, $0.7 and $0.7, respectively	9.9	9.8	19.8	19.8
Other financing costs	0.4	0.3	0.7	0.7
Allowance for funds used during construction — debt	(0.5)	(0.3)	(1)	(0.6)
Total interest charges and financing costs	9.4	9.5	18.8	19.2
Income before income taxes	13.4	12.9	43.7	45.4
Income tax expense (benefit)	1.3	4.3	(2)	12.8
Net income	$ 12.1	$ 8.6	$ 45.7	$ 32.6

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating activities
Net income	$ 45.7	$ 32.6
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	78	68.9
Deferred income taxes	(15.2)	2
Allowance for equity funds used during construction	(2.5)	(1.4)
Provision for Bad Debts	2.8	3.5
Changes in operating assets and liabilities:
Accounts receivable	(4.2)	6.8
Accrued unbilled revenues	10.4	11.5
Inventories	0.2	0.7
Other current assets	(0.3)	(0.4)
Accounts payable	(3)	(8.9)
Net regulatory assets and liabilities	5.3	2.5
Other current liabilities	(1.9)	3.6
Pension and other employee benefit obligations	(6.9)	(7.1)
Other, net	0.2	1
Net cash provided by operating activities	108.6	115.3
Investing activities
Utility capital/construction expenditures	(121)	(86.8)
Net cash used in investing activities	(121)	(86.8)
Financing activities
Repayments of short-term borrowings, net	(65)	1
Proceeds from (Repayments of) Long-term Debt	97.6	(0.1)
Capital contributions from parent	37	14.8
Dividends paid to parent	(31.6)	(41.7)
Other, net	(0.2)	0
Net cash provided by (used in) financing activities	37.8	(28)
Net change in cash, cash equivalents and restricted cash	25.4	0.5
Cash, cash equivalents and restricted cash at beginning of period	1.3	2.2
Cash, cash equivalents and restricted cash at end of period	26.7	2.7
Supplemental disclosure of cash flow information:
Cash paid for interest (net of amounts capitalized)	(17.9)	(18.2)
Cash paid for income taxes, net	(13.1)	(3.9)
Supplemental disclosure of non-cash investing transactions:
Accrued property, plant and equipment additions	18.5	11.5
Inventory transfers to property, plant and equipment	2.3	2.4
Allowance for equity funds used during construction	$ 2.5	$ 1.4

CONSOLIDATED BALANCE SHEETS (UN

CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 26.7	$ 1.3
Accounts receivable, net	63.4	59.2
Accrued unbilled revenues	42.5	53.1
Inventories	13.4	16
Regulatory assets	45.9	71.9
Prepaid taxes	23.2	23
Prepayments and other	4.9	4.6
Total current assets	220	229.1
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment, net	2,416.8	2,359.4
Other assets
Regulatory assets	218	224.4
Other	3.5	3.1
Total other assets	221.5	227.5
Total assets	2,858.3	2,816
Current liabilities
Short-term debt	0	65
Accounts payable	37.1	53.6
Accounts payable to affiliates	21.4	19
Dividends payable to parent	20.2	14.7
Regulatory liabilities	63.9	78.9
Taxes Accrued	7.7	6.8
Environmental liabilities	4.5	5.7
Accrued interest	9.5	9.3
Other	15.9	20.7
Total current liabilities	180.2	273.7
Deferred credits and other liabilities
Deferred income taxes	302.9	298.1
Deferred investment tax credits	6.2	6.5
Regulatory liabilities	360.6	370.8
Environmental liabilities	17	17.8
Customer advances	19.5	18.5
Pension and employee benefit obligations	26.6	33.4
Other	23.8	22.6
Total deferred credits and other liabilities	756.6	767.7
Capitalization
Long-term debt	906	808
Common stock — 1,000,000 shares authorized of $100 par value; 933,000 shares outstanding at June 30, 2020 and Dec. 31, 2019, respectively	$ 93.3	$ 93.3
Common stock, shares authorized (in shares)	1,000,000	1,000,000
Common stock, par value (in dollars per share)	$ 100	$ 100
Common stock, shares outstanding (in shares)	933,000	933,000
Additional paid in capital	$ 577.7	$ 537.3
Retained earnings	344.5	336
Total common stockholder’s equity	1,015.5	966.6
Total liabilities and equity	$ 2,858.3	$ 2,816

Selected Balance Sheet Data

Selected Balance Sheet Data	6 Months Ended
	Jun. 30, 2020
Balance Sheet Related Disclosures [Abstract]
Selected Balance Sheet Data	(Millions of Dollars) June 30, 2020 Dec. 31, 2019 Accounts receivable, net Accounts receivable $ 69.5 $ 64.7 Less allowance for bad debts (6.1) (5.5) Accounts receivable, net $ 63.4 $ 59.2 (Millions of Dollars) June 30, 2020 Dec. 31, 2019 Inventories Materials and supplies $ 7.3 $ 6.8 Fuel 4.1 4.0 Natural gas 2.0 5.2 Total inventories $ 13.4 $ 16.0 (Millions of Dollars) June 30, 2020 Dec. 31, 2019 Property, plant and equipment, net Electric plant $ 3,070.6 $ 3,024.6 Natural gas plant 375.2 365.5 Common and other property 203.7 201.5 Construction work in progress 120.4 82.8 Total property, plant and equipment 3,769.9 3,674.4 Less accumulated depreciation (1,353.1) (1,315.0) Property, plant and equipment, net $ 2,416.8 $ 2,359.4

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	The significant accounting policies set forth in Note 1 to the consolidated financial statements in the NSP-Wisconsin Annual Report on Form 10-K for the year ended Dec. 31, 2019, appropriately represent, in all material respects, the current status of accounting policies and are incorporated herein by reference.

Borrowings and Other Financing

Borrowings and Other Financing Instruments	6 Months Ended
	Jun. 30, 2020
Debt Disclosure [Abstract]
Borrowings and Other Financing Instruments	Short-Term Borrowings NSP-Wisconsin meets its short-term liquidity requirements primarily through the issuance of commercial paper and borrowings under its credit facility. Commercial Paper — Commercial paper outstanding for NSP-Wisconsin was as follows: (Amounts in Millions, Except Interest Rates) Three Months Ended June 30, 2020 Year Ended Dec. 31, 2019 Borrowing limit $ 150 $ 150 Amount outstanding at period end — 65 Average amount outstanding 41 51 Maximum amount outstanding 91 93 Weighted average interest rate, computed on a daily basis 1.04 % 2.38 % Weighted average interest rate at period end N/A 1.97 Letters of Credit — NSP-Wisconsin uses letters of credit, generally with terms of one year, to provide financial guarantees for certain operating obligations. At June 30, 2020 and Dec. 31, 2019, there were no letters of credit outstanding. Revolving Credit Facility — In order to use its commercial paper program to fulfill short-term funding needs, NSP-Wisconsin must have a revolving credit facility in place at least equal to the amount of its commercial paper borrowing limit and cannot issue commercial paper in an aggregate amount exceeding available capacity under this credit facility. The line of credit provides short-term financing in the form of notes payable to banks, letters of credit and back-up support for commercial paper borrowings. NSP-Wisconsin has the right to request an extension of the revolving credit facility termination date for an additional one-year period. All extension requests are subject to majority bank group approval. As of June 30, 2020, NSP-Wisconsin had the following committed revolving credit facility available (in millions of dollars): Credit Facility (a) Outstanding (b) Available $ 150 $ — $ 150 (a) This credit facility expires in June 2024. (b) Includes outstanding commercial paper. All credit facility bank borrowings, outstanding letters of credit and outstanding commercial paper reduce the available capacity under the credit facility. NSP-Wisconsin had no direct advances on the credit facility outstanding at June 30, 2020 and Dec. 31, 2019. Other Short-Term Borrowings — As of June 30, 2020 and Dec. 31, 2019, Clearwater Investments, Inc., a NSP-Wisconsin subsidiary, had no notes payable to Xcel Energy Inc. Long-Term Borrowings During the six months ended June 30, 2020, NSP-Wisconsin issued $100 million of 3.05% first mortgage bonds due May 1, 2051.

Revenues

Revenues	6 Months Ended
	Jun. 30, 2020
Revenue from Contract with Customer [Abstract]
Revenues	Revenue is classified by the type of goods/services rendered and market/customer type. NSP-Wisconsin’s operating revenues consists of the following: Three Months Ended June 30, 2020 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 59.6 $ 10.6 $ — $ 70.2 C&I 93.2 6.8 — 100.0 Other 2.0 — 0.2 2.2 Total retail 154.8 17.4 0.2 172.4 Interchange 41.5 — — 41.5 Other 0.1 1.1 — 1.2 Total revenue from contracts with customers 196.4 18.5 0.2 215.1 Alternative revenue and other 2.9 0.5 — 3.4 Total revenues $ 199.3 $ 19.0 $ 0.2 $ 218.5 Three Months Ended June 30, 2019 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 54.1 $ 10.8 $ — $ 64.9 C&I 105.1 8.6 — 113.7 Other 2.1 — 0.1 2.2 Total retail 161.3 19.4 0.1 180.8 Interchange 43.5 — — 43.5 Other 0.1 0.9 — 1.0 Total revenue from contracts with customers 204.9 20.3 0.1 225.3 Alternative revenue and other 3.0 0.6 — 3.6 Total revenues $ 207.9 $ 20.9 $ 0.1 $ 228.9 Six Months Ended June 30, 2020 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 124.6 $ 35.1 $ — $ 159.7 C&I 193.6 26.3 — 219.9 Other 3.6 — 0.2 3.8 Total retail 321.8 61.4 0.2 383.4 Interchange 82.4 — — 82.4 Other 0.6 1.9 — 2.5 Total revenue from contracts with customers 404.8 63.3 0.2 468.3 Alternative revenue and other 6.3 0.9 — 7.2 Total revenues $ 411.1 $ 64.2 $ 0.2 $ 475.5 Six Months Ended June 30, 2019 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 121.5 $ 44.4 $ — $ 165.9 C&I 203.6 34.4 — 238.0 Other 3.6 — 0.2 3.8 Total retail 328.7 78.8 0.2 407.7 Interchange 87.6 — — 87.6 Other 0.6 2.0 — 2.6 Total revenue from contracts with customers 416.9 80.8 0.2 497.9 Alternative revenue and other 6.0 1.2 — 7.2 Total revenues $ 422.9 $ 82.0 $ 0.2 $ 505.1

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	6. Income Taxes Note 7 to the consolidated financial statements included in NSP-Wisconsin’s Annual Report on Form 10-K for the year ended Dec. 31, 2019 represents, in all material respects, the current status of other income tax matters except to the extent noted below, and are incorporated herein by reference. The following table reconciles the difference between the statutory rate and the ETR: Six Months Ended June 30 2020 2019 Federal statutory rate 21.0 % 21.0 % State tax (net of federal tax effect) 6.2 6.2 Increases (decreases) in tax from: Plant regulatory differences (a) (18.4) (0.5) Nonplant ADIT amortization (12.5) — Tax credits, net of NOL & tax credit allowances (1.7) (1.0) Prior period adjustments — 2.2 Other (net) 0.8 0.3 Effective income tax rate (4.6) % 28.2 % (a) Regulatory differences for income tax primarily relates to the credit of excess deferred taxes to customers through the average rate assumption method. Income tax benefits associated with the credit of excess deferred credits are offset by corresponding revenue reductions. Federal Audits — NSP-Wisconsin is a member of the Xcel Energy affiliated group that files a consolidated federal income tax return. Statute of limitations applicable to Xcel Energy’s consolidated federal income tax returns expire as follows: Tax Years Expiration 2009 - 2013 September 2020 2014 - 2016 June 2021 In 2017, the IRS concluded the audit of tax years 2012 and 2013 and proposed an adjustment that would impact Xcel Energy’s NOL and ETR. Xcel Energy filed a protest with the IRS. In April 2020, Xcel Energy and Appeals reached an agreement and no material adjustments were required. In 2018, the IRS began an audit of tax years 2014-2016. As of June 30, 2020, no adjustments have been proposed. State Audits — NSP-Wisconsin is a member of the Xcel Energy affiliated group that files consolidated state income tax returns. As of June 30, 2020, NSP-Wisconsin’s earliest open tax year subject to examination by state taxing authorities under applicable statutes of limitations is 2014. In 2018, Wisconsin began an audit of tax years 2014-2016. As of June 30, 2020, no material adjustments have been proposed. Unrecognized Benefits — Unrecognized tax benefit balance includes permanent tax positions, which if recognized would affect the annual ETR. In addition, the unrecognized tax benefit balance includes temporary tax positions for which ultimate deductibility is highly certain, but for which there is uncertainty about the timing of such deductibility. A change in the period of deductibility would not affect the ETR but would accelerate the payment to the taxing authority to an earlier period. Unrecognized tax benefits — permanent vs. temporary: (Millions of Dollars) June 30, 2020 Dec. 31, 2019 Unrecognized tax benefit — Permanent tax positions $ 2.6 $ 2.6 Unrecognized tax benefit — Temporary tax positions 0.8 0.8 Total unrecognized tax benefit $ 3.4 $ 3.4 Unrecognized tax benefits were reduced by tax benefits associated with NOL and tax credit carryforwards: (Millions of Dollars) June 30, 2020 Dec. 31, 2019 NOL and tax credit carryforwards $ (2.1) $ (2.2) Net deferred tax liability associated with the unrecognized tax benefit amounts and related NOLs and tax credits carryforwards were $1.3 million at June 30, 2020 and $1.2 million at Dec. 31, 2019. As the IRS and state audits progress, it is reasonably possible that the amount of unrecognized tax benefit could decrease up to approximately $1.8 million in the next 12 months. Payables for interest related to unrecognized tax benefits were not material and no amounts were accrued for penalties related to unrecognized tax benefits as of June 30, 2020 and Dec. 31, 2019, respectively.

Fair Value of Financial Assets

Fair Value of Financial Assets and Liabilities	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets and Liabilities	Fair Value Measurements Accounting guidance for fair value measurements and disclosures provides a single definition of fair value and requires disclosures about assets and liabilities measured at fair value. A hierarchical framework for disclosing the observability of the inputs utilized in measuring assets and liabilities at fair value is established by this guidance. • Level 1 — Quoted prices are available in active markets for identical assets or liabilities as of the reporting date. The types of assets and liabilities included in Level 1 are highly liquid and actively traded instruments with quoted prices; • Level 2 — Pricing inputs are other than quoted prices in active markets, but are either directly or indirectly observable as of the reporting date. The types of assets and liabilities included in Level 2 are typically either comparable to actively traded securities or contracts, or priced with models using highly observable inputs; and • Level 3 — Significant inputs to pricing have little or no observability as of the reporting date. The types of assets and liabilities included in Level 3 are those valued with models requiring significant management judgment or estimation. Specific valuation methods include: Cash equivalents — The fair values of cash equivalents are generally based on cost plus accrued interest; money market funds are measured using quoted net asset value. Interest rate derivatives — The fair values of interest rate derivatives are based on broker quotes that utilize current market interest rate forecasts. Commodity derivatives — The methods used to measure the fair value of commodity derivative forwards and options utilize forward prices and volatilities, as well as pricing adjustments for specific delivery locations, and are generally assigned a Level 2 classification. When contractual settlements relate to inactive delivery locations or extend to periods beyond those readily observable on active exchanges or quoted by brokers, the significance of the use of less observable forecasts of forward prices and volatilities on a valuation is evaluated and may result in Level 3 classification. Derivative Instruments Fair Value Measurements NSP-Wisconsin enters into derivative instruments, including forward contracts, futures, swaps and options, for trading purposes and to manage risk in connection with changes in interest rates and utility commodity prices. Interest Rate Derivatives — NSP-Wisconsin may enter into various instruments that effectively fix the yield or price on a specified benchmark interest rate for an anticipated debt issuance for a specific period. These derivative instruments are generally designated as cash flow hedges for accounting purposes. As of June 30, 2020 and Dec. 31, 2019, there were no interest rate derivatives designated as cash flow hedges. Commodity Derivatives — NSP-Wisconsin may enter into derivative instruments to manage variability of future cash flows from changes in commodity prices in its electric and natural gas operations, as well as for trading purposes. This could include the purchase or sale of natural gas to generate electric energy and natural gas for resale. Gross notional amounts of commodity options: (Amounts in Millions) (a)(b) June 30, 2020 Dec. 31, 2019 Million British thermal units of natural gas 0.4 0.1 (a) Amounts are not reflective of net positions in the underlying commodities. (b) Notional amounts for options are included on a gross basis, but are weighted for the probability of exercise. Consideration of Credit Risk and Concentrations — NSP-Wisconsin continuously monitors the creditworthiness of counterparties to its interest rate derivatives and commodity derivative contracts prior to settlement, and assesses each counterparty’s ability to perform on the transactions set forth in the contracts. Impact of credit risk was immaterial to the fair value of unsettled commodity derivatives presented in the consolidated balance sheets. Impact of Derivative Activities on Income and Accumulated Other Comprehensive Loss — Changes in the fair value of natural gas commodity derivatives resulted in $0.1 million net losses and immaterial net losses for the three and six months ended June 30, 2020, respectively, which were recognized as regulatory assets and liabilities. There were immaterial net losses for the three and six months ended June 30, 2019, respectively, which were recognized as regulatory assets and liabilities. The classification as a regulatory asset or liability is based on commission approved regulatory recovery mechanisms. During both the three months ended June 30, 2020 and 2019, there were no settlement gains or losses on natural gas commodity derivatives. During the six months ended June 30, 2020 and 2019, there were $0.9 million of net settlement losses and $0.2 million of net settlement gains on natural gas commodity derivatives, respectively, which were recognized subject to purchased natural gas cost recovery mechanisms, which result in reclassifications of derivative settlement gains and losses out of income to a regulatory asset or liability, as appropriate. NSP-Wisconsin had no derivative instruments designated as fair value hedges during the three and six months ended June 30, 2020 and 2019, respectively. Recurring Fair Value Measurements — NSP-Wisconsin's derivative assets measured at fair value on a recurring basis were as follows: June 30, 2020 Fair Value Fair Value Netting (a) Total (b) (Millions of Dollars) Level 1 Level 2 Level 3 Current derivative assets Natural gas commodity $ — $ 0.2 $ — $ 0.2 $ — $ 0.2 Dec. 31, 2019 Fair Value Fair Value Netting (a) Total (b) (Millions of Dollars) Level 1 Level 2 Level 3 Current derivative assets Natural gas commodity $ — $ 0.5 $ — $ 0.5 $ — $ 0.5 (a) NSP-Wisconsin nets derivative instruments and related collateral in its consolidated balance sheet when supported by a legally enforceable master netting agreement, and all derivative instruments and related collateral amounts were subject to master netting agreements at June 30, 2020 and Dec. 31, 2019. The counterparty netting amounts presented exclude settlement receivables and payables and non-derivative amounts that may be subject to the same master netting agreements. (b) Included in prepayments and other current assets balance of $4.9 million at June 30, 2020 and $4.6 million at Dec. 31, 2019 in the consolidated balance sheets. Fair Value of Long-Term Debt Other financial instruments for which the carrying amount did not equal fair value: June 30, 2020 Dec. 31, 2019 (Millions of Dollars) Carrying Amount Fair Value Carrying Amount Fair Value Long-term debt, including current portion $ 906.0 $ 1,124.3 $ 808.0 $ 924.3 Fair value of NSP-Wisconsin’s long-term debt is estimated based on recent trades and observable spreads from benchmark interest rates for similar securities. Fair value estimates are based on information available to management as of June 30, 2020 and Dec. 31, 2019, and given the observability of the inputs, fair values presented for long-term debt were assigned as Level 2.

Benefit Plans and Other Postret

Benefit Plans and Other Postretirement Benefits	6 Months Ended
	Jun. 30, 2020
Retirement Benefits [Abstract]
Benefit Plans and Other Postretirement Benefits	Components of Net Periodic Benefit Cost Three Months Ended June 30 2020 2019 2020 2019 (Millions of Dollars) Pension Benefits Postretirement Health Service cost $ 1.2 $ 1.1 $ — $ — Interest cost (a) 1.2 1.4 0.1 0.1 Expected return on plan assets (a) (2.1) (2.0) — — Amortization of prior service credit (a) — — (0.1) (0.1) Amortization of net loss (a) 1.2 1.1 0.1 0.1 Net periodic benefit cost $ 1.5 $ 1.6 $ 0.1 $ 0.1 Costs not recognized due to effects of 1.8 — — — Net benefit cost recognized for financial reporting $ 3.3 $ 1.6 $ 0.1 $ 0.1 Six Months Ended June 30 2020 2019 2020 2019 (Millions of Dollars) Pension Benefits Postretirement Health Service cost $ 2.3 $ 2.2 $ — $ — Interest cost (a) 2.4 2.9 0.2 0.3 Expected return on plan assets (a) (4.2) (4.2) — — Amortization of prior service credit (a) — — (0.1) (0.2) Amortization of net loss (a) 2.4 2.2 0.1 0.1 Net periodic benefit cost $ 2.9 $ 3.1 $ 0.2 $ 0.2 Costs not recognized due to effects of 3.7 0.2 — — Net benefit cost recognized for financial reporting $ 6.6 $ 3.3 $ 0.2 $ 0.2 (a) The components of net periodic cost other than the service cost component are included in the line item “other expense, net” in the consolidated statement of income or capitalized on the consolidated balance sheet as a regulatory asset. In January 2020, contributions of $150.0 million were made across four of Xcel Energy’s pension plans, of which $6.7 million was attributable to NSP-Wisconsin. Xcel Energy does not expect additional pension contributions during 2020.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	The following includes commitments, contingencies and unresolved contingencies that are material to NSP-Wisconsin’s financial position. Legal NSP-Wisconsin is involved in various litigation matters in the ordinary course of business. The assessment of whether a loss is probable or is a reasonable possibility, and whether the loss or a range of loss is estimable, often involves a series of complex judgments about future events. Management maintains accruals for losses probable of being incurred and subject to reasonable estimation. Management is sometimes unable to estimate an amount or range of a reasonably possible loss in certain situations, including but not limited to, when (1) the damages sought are indeterminate, (2) the proceedings are in the early stages, or (3) the matters involve novel or unsettled legal theories. In such cases, there is considerable uncertainty regarding the timing or ultimate resolution of such matters, including a possible eventual loss. For current proceedings not specifically reported herein, management does not anticipate that the ultimate liabilities, if any, would have a material effect on NSP-Wisconsin’s financial statements. Unless otherwise required by GAAP, legal fees are expensed as incurred. Gas Trading Litigation — e prime is a wholly owned subsidiary of Xcel Energy. e prime was in the business of natural gas trading and marketing but has not engaged in natural gas trading or marketing activities since 2003. Multiple lawsuits seeking monetary damages were commenced against e prime and its affiliates, including Xcel Energy, between 2003 and 2009 alleging fraud and anticompetitive activities in conspiring to restrain the trade of natural gas and manipulate natural gas prices. Cases were all consolidated in the U.S. District Court in Nevada. Two cases remain active which include an MDL matter consisting of a Colorado purported class (Breckenridge) and a Wisconsin purported class (Arandell Corp.). Breckenridge/Colorado — In February 2019, the MDL panel remanded Breckenridge back to the U.S. District Court in Colorado. Arandell Corp. — In February 2019, the case was remanded back to the U.S. District Court in Wisconsin. Plaintiffs are seeking class certification. It is uncertain when the court will rule on this issue. Xcel Energy has concluded that a loss is remote for both remaining lawsuits. Rate Matters MISO ROE Complaints —In November 2013 and February 2015, customers filed complaints against MISO TOs including NSP-Minnesota and NSP-Wisconsin. The first complaint argued for a reduction in the base ROE in MISO transmission formula rates from 12.38% to 9.15%, and removal of ROE adders (including those for RTO membership). The second complaint sought to reduce base ROE from 12.38% to 8.67%. In September 2016, the FERC issued an order granting a 10.32% base ROE (10.82% with the RTO adder) effective for the first complaint period of Nov. 12, 2013 to Feb. 11, 2015 and subsequent to the date of the order. The United States Court of Appeals for the District of Columbia Circuit subsequently vacated and remanded FERC Opinion No. 531, which had established the ROE methodology on which the September 2016 FERC order was based. In November 2019, the FERC issued an order adopting a new ROE methodology and settling the MISO base ROE at 9.88% (10.38% with the RTO adder), effective Sept. 28, 2016 and for the Nov. 12, 2013 to Feb. 11, 2015 refund period. The FERC also dismissed the second complaint. In December 2019, MISO TOs filed a request for rehearing. Customers also filed requests for rehearing claiming, among other points, that the FERC erred by dismissing the second complaint without refunds. In March 2020, the FERC issued a Notice of Proposed Rulemaking regarding changes to its policies for transmission incentives, including a proposal to increase the RTO participation adder from 50 to 100 basis points and to make the adder available regardless of whether a utility’s ongoing participation in the RTO is voluntary or required by legislation or a regulator. In May 2020, the FERC issued Opinion No. 569-A, which granted rehearing in part to Opinion 569 and further refined the FERC’s ROE methodology, most significantly to incorporate the risk premium model (in addition to the discounted cash flow and capital asset pricing models), resulting in a new base ROE of 10.02%, effective Sept. 28, 2016 and for the refund period in the first complaint. The FERC also affirmed its decision in Opinion 569 to dismiss the second complaint. Although the May 2020 Order remains subject to pending requests for rehearing, as well as the pending judicial review, a liability has been recognized for the best estimate of final refunds to customers. Environmental MGP, Landfill and Disposal Sites Ashland MGP Site — NSP-Wisconsin was named a responsible party for contamination at the Ashland/Northern States Power Lakefront Superfund Site (the Site) in Ashland, Wisconsin. Remediation was completed in 2019 and restoration activities were completed in 2020. Groundwater treatment activities will continue for many years. The cost estimate for remediation and restoration of the entire site is approximately $199.1 million. At June 30, 2020 and Dec. 31, 2019, NSP-Wisconsin had a total liability of $21.4 million and $23.2 million, respectively, for the entire site. NSP-Wisconsin has deferred the unrecovered portion of the estimated Site remediation and restoration costs as a regulatory asset. The PSCW has authorized NSP-Wisconsin rate recovery for all remediation and restoration costs incurred at the Site and application of a 3% carrying charge to the regulatory asset. In addition to the Ashland Site, NSP-Wisconsin is currently investigating, remediating or performing post-closure actions at two other MGP, landfill or other disposal sites across its service territories. NSP-Wisconsin has recognized its best estimate of costs/liabilities that will result from final resolution of these issues, however, the outcome and timing is unknown. In addition, there may be insurance recovery and/or recovery from other potentially responsible parties, offsetting a portion of costs incurred.

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2020
Segment Reporting [Abstract]
Segment Information	NSP-Wisconsin evaluates performance based on profit or loss generated from the product or service provided. These segments are managed separately because the revenue streams are dependent upon regulated rate recovery, which is separately determined for each segment. NSP-Wisconsin has the following reportable segments: • Regulated Electric — The regulated electric utility segment generates electricity, which is transmitted and distributed in Wisconsin and Michigan; and • Regulated Natural Gas — The regulated natural gas utility segment purchases, transports, stores and distributes natural gas in portions of Wisconsin and Michigan. NSP-Wisconsin presents Other, which includes operating segments with revenues below the necessary quantitative thresholds. Those operating segments primarily include investments in rental housing projects that qualify for low-income housing tax credits. Asset and capital expenditure information is not provided for NSP-Wisconsin's reportable segments. As an integrated electric and natural gas utility, NSP-Wisconsin operates significant assets that are not dedicated to a specific business segment. Reporting assets and capital expenditures by business segment would require arbitrary and potentially misleading allocations, which may not necessarily reflect the assets required for the operation of the business segments on a stand-alone basis. Certain costs, such as common depreciation, common O&M expenses and interest expense are allocated based on cost causation allocators across each segment. In addition, a general allocator is used for certain general and administrative expenses, including office supplies, rent, property insurance and general advertising. NSP-Wisconsin's segment information for the three and six months ended June 30: Three Months Ended June 30 (Millions of Dollars) 2020 2019 Regulated Electric Operating revenues (a) $ 199.3 $ 207.9 Intersegment revenues 0.1 0.1 Total operating revenue $ 199.4 $ 208.0 Net income 16.3 10.9 Regulated Natural Gas Operating revenues $ 19.0 $ 20.9 Intersegment revenues 0.2 — Total operating revenue $ 19.2 $ 20.9 Net loss (2.9) (1.3) All Other Operating revenues $ 0.2 $ 0.1 Net loss (1.3) (1.0) Consolidated Total Operating revenues (a) $ 218.8 $ 229.0 Reconciling eliminations (0.3) (0.1) Total operating revenues $ 218.5 $ 228.9 Net income 12.1 8.6 (a) Operating revenues include $41.5 million and $43.5 million of affiliate electric revenue for the three months ended June 30, 2020 and 2019, respectively. Six Months Ended June 30 (Millions of Dollars) 2020 2019 Regulated Electric Operating revenues (a) $ 411.1 $ 422.9 Intersegment revenues 0.2 0.2 Total operating revenue $ 411.3 $ 423.1 Net income 41.0 24.1 Regulated Natural Gas Operating revenues $ 64.2 $ 82.0 Intersegment revenues 0.3 0.2 Total operating revenues $ 64.5 $ 82.2 Net income 6.0 9.2 All Other Operating revenues $ 0.2 $ 0.2 Net loss (1.3) (0.7) Consolidated Total Operating revenues (a) $ 476.0 $ 505.5 Reconciling eliminations (0.5) (0.4) Total operating revenues $ 475.5 $ 505.1 Net income 45.7 32.6 (a) Operating revenues include $82.4 million and $87.6 million of affiliate electric revenue for the six months ended June 30, 2020 and 2019, respectively.

Selected Balance Sheet Data (Ta

Selected Balance Sheet Data (Tables)	6 Months Ended
	Jun. 30, 2020
Balance Sheet Related Disclosures [Abstract]
Accounts Receivable, Net	(Millions of Dollars) June 30, 2020 Dec. 31, 2019 Accounts receivable, net Accounts receivable $ 69.5 $ 64.7 Less allowance for bad debts (6.1) (5.5) Accounts receivable, net $ 63.4 $ 59.2
Inventories	(Millions of Dollars) June 30, 2020 Dec. 31, 2019 Inventories Materials and supplies $ 7.3 $ 6.8 Fuel 4.1 4.0 Natural gas 2.0 5.2 Total inventories $ 13.4 $ 16.0
Property, Plant and Equipment, Net	(Millions of Dollars) June 30, 2020 Dec. 31, 2019 Property, plant and equipment, net Electric plant $ 3,070.6 $ 3,024.6 Natural gas plant 375.2 365.5 Common and other property 203.7 201.5 Construction work in progress 120.4 82.8 Total property, plant and equipment 3,769.9 3,674.4 Less accumulated depreciation (1,353.1) (1,315.0) Property, plant and equipment, net $ 2,416.8 $ 2,359.4

Borrowings and Other Financin_2

Borrowings and Other Financing Instruments (Tables)	6 Months Ended
	Jun. 30, 2020
Borrowings and Other Financing Instruments [Abstract]
Credit Facilities	As of June 30, 2020, NSP-Wisconsin had the following committed revolving credit facility available (in millions of dollars): Credit Facility (a) Outstanding (b) Available $ 150 $ — $ 150 (a) This credit facility expires in June 2024. (b) Includes outstanding commercial paper.
Commercial Paper
Borrowings and Other Financing Instruments [Abstract]
Short-Term Borrowings	Commercial paper outstanding for NSP-Wisconsin was as follows: (Amounts in Millions, Except Interest Rates) Three Months Ended June 30, 2020 Year Ended Dec. 31, 2019 Borrowing limit $ 150 $ 150 Amount outstanding at period end — 65 Average amount outstanding 41 51 Maximum amount outstanding 91 93 Weighted average interest rate, computed on a daily basis 1.04 % 2.38 % Weighted average interest rate at period end N/A 1.97

Revenues (Tables)

Revenues (Tables)	6 Months Ended
	Jun. 30, 2020
Revenue from Contract with Customer [Abstract]
Disaggregation of revenue	NSP-Wisconsin’s operating revenues consists of the following: Three Months Ended June 30, 2020 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 59.6 $ 10.6 $ — $ 70.2 C&I 93.2 6.8 — 100.0 Other 2.0 — 0.2 2.2 Total retail 154.8 17.4 0.2 172.4 Interchange 41.5 — — 41.5 Other 0.1 1.1 — 1.2 Total revenue from contracts with customers 196.4 18.5 0.2 215.1 Alternative revenue and other 2.9 0.5 — 3.4 Total revenues $ 199.3 $ 19.0 $ 0.2 $ 218.5 Three Months Ended June 30, 2019 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 54.1 $ 10.8 $ — $ 64.9 C&I 105.1 8.6 — 113.7 Other 2.1 — 0.1 2.2 Total retail 161.3 19.4 0.1 180.8 Interchange 43.5 — — 43.5 Other 0.1 0.9 — 1.0 Total revenue from contracts with customers 204.9 20.3 0.1 225.3 Alternative revenue and other 3.0 0.6 — 3.6 Total revenues $ 207.9 $ 20.9 $ 0.1 $ 228.9 Six Months Ended June 30, 2020 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 124.6 $ 35.1 $ — $ 159.7 C&I 193.6 26.3 — 219.9 Other 3.6 — 0.2 3.8 Total retail 321.8 61.4 0.2 383.4 Interchange 82.4 — — 82.4 Other 0.6 1.9 — 2.5 Total revenue from contracts with customers 404.8 63.3 0.2 468.3 Alternative revenue and other 6.3 0.9 — 7.2 Total revenues $ 411.1 $ 64.2 $ 0.2 $ 475.5 Six Months Ended June 30, 2019 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 121.5 $ 44.4 $ — $ 165.9 C&I 203.6 34.4 — 238.0 Other 3.6 — 0.2 3.8 Total retail 328.7 78.8 0.2 407.7 Interchange 87.6 — — 87.6 Other 0.6 2.0 — 2.6 Total revenue from contracts with customers 416.9 80.8 0.2 497.9 Alternative revenue and other 6.0 1.2 — 7.2 Total revenues $ 422.9 $ 82.0 $ 0.2 $ 505.1

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	The following table reconciles the difference between the statutory rate and the ETR: Six Months Ended June 30 2020 2019 Federal statutory rate 21.0 % 21.0 % State tax (net of federal tax effect) 6.2 6.2 Increases (decreases) in tax from: Plant regulatory differences (a) (18.4) (0.5) Nonplant ADIT amortization (12.5) — Tax credits, net of NOL & tax credit allowances (1.7) (1.0) Prior period adjustments — 2.2 Other (net) 0.8 0.3 Effective income tax rate (4.6) % 28.2 % (a)
Summary of Statute of Limitations Applicable to Open Tax Years [Table Text Block]	Federal Audits — NSP-Wisconsin is a member of the Xcel Energy affiliated group that files a consolidated federal income tax return. Statute of limitations applicable to Xcel Energy’s consolidated federal income tax returns expire as follows: Tax Years Expiration 2009 - 2013 September 2020 2014 - 2016 June 2021
Reconciliation of Unrecognized Tax Benefits	Unrecognized tax benefits — permanent vs. temporary: (Millions of Dollars) June 30, 2020 Dec. 31, 2019 Unrecognized tax benefit — Permanent tax positions $ 2.6 $ 2.6 Unrecognized tax benefit — Temporary tax positions 0.8 0.8 Total unrecognized tax benefit $ 3.4 $ 3.4
Tax Benefits Associated with NOL and Tax Credit Carryforwards	Unrecognized tax benefits were reduced by tax benefits associated with NOL and tax credit carryforwards: (Millions of Dollars) June 30, 2020 Dec. 31, 2019 NOL and tax credit carryforwards $ (2.1) $ (2.2)

Fair Value of Financial Asset_2

Fair Value of Financial Assets and Liabilities (Tables)	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Gross Notional Amounts of Commodity Forwards and Options	Gross notional amounts of commodity options: (Amounts in Millions) (a)(b) June 30, 2020 Dec. 31, 2019 Million British thermal units of natural gas 0.4 0.1 (a) Amounts are not reflective of net positions in the underlying commodities. (b) Notional amounts for options are included on a gross basis, but are weighted for the probability of exercise.
Derivative Assets and Liabilities Measured at Fair Value on a Recurring Basis by Hierarchy Level	Recurring Fair Value Measurements — NSP-Wisconsin's derivative assets measured at fair value on a recurring basis were as follows: June 30, 2020 Fair Value Fair Value Netting (a) Total (b) (Millions of Dollars) Level 1 Level 2 Level 3 Current derivative assets Natural gas commodity $ — $ 0.2 $ — $ 0.2 $ — $ 0.2 Dec. 31, 2019 Fair Value Fair Value Netting (a) Total (b) (Millions of Dollars) Level 1 Level 2 Level 3 Current derivative assets Natural gas commodity $ — $ 0.5 $ — $ 0.5 $ — $ 0.5 (a) NSP-Wisconsin nets derivative instruments and related collateral in its consolidated balance sheet when supported by a legally enforceable master netting agreement, and all derivative instruments and related collateral amounts were subject to master netting agreements at June 30, 2020 and Dec. 31, 2019. The counterparty netting amounts presented exclude settlement receivables and payables and non-derivative amounts that may be subject to the same master netting agreements. (b) Included in prepayments and other current assets balance of $4.9 million at June 30, 2020 and $4.6 million at Dec. 31, 2019 in the consolidated balance sheets.
Carrying Amount and Fair Value of Long-term Debt	Other financial instruments for which the carrying amount did not equal fair value: June 30, 2020 Dec. 31, 2019 (Millions of Dollars) Carrying Amount Fair Value Carrying Amount Fair Value Long-term debt, including current portion $ 906.0 $ 1,124.3 $ 808.0 $ 924.3

Benefit Plans and Other Postr_2

Benefit Plans and Other Postretirement Benefits (Tables)	6 Months Ended
	Jun. 30, 2020
Retirement Benefits [Abstract]
Components of Net Periodic Benefit Cost	Components of Net Periodic Benefit Cost Three Months Ended June 30 2020 2019 2020 2019 (Millions of Dollars) Pension Benefits Postretirement Health Service cost $ 1.2 $ 1.1 $ — $ — Interest cost (a) 1.2 1.4 0.1 0.1 Expected return on plan assets (a) (2.1) (2.0) — — Amortization of prior service credit (a) — — (0.1) (0.1) Amortization of net loss (a) 1.2 1.1 0.1 0.1 Net periodic benefit cost $ 1.5 $ 1.6 $ 0.1 $ 0.1 Costs not recognized due to effects of 1.8 — — — Net benefit cost recognized for financial reporting $ 3.3 $ 1.6 $ 0.1 $ 0.1 Six Months Ended June 30 2020 2019 2020 2019 (Millions of Dollars) Pension Benefits Postretirement Health Service cost $ 2.3 $ 2.2 $ — $ — Interest cost (a) 2.4 2.9 0.2 0.3 Expected return on plan assets (a) (4.2) (4.2) — — Amortization of prior service credit (a) — — (0.1) (0.2) Amortization of net loss (a) 2.4 2.2 0.1 0.1 Net periodic benefit cost $ 2.9 $ 3.1 $ 0.2 $ 0.2 Costs not recognized due to effects of 3.7 0.2 — — Net benefit cost recognized for financial reporting $ 6.6 $ 3.3 $ 0.2 $ 0.2 (a) The components of net periodic cost other than the service cost component are included in the line item “other expense, net” in the consolidated statement of income or capitalized on the consolidated balance sheet as a regulatory asset.	[1]
[1]	The components of net periodic cost other than the service cost component are included in the line item “other expense, net” in the consolidated statement of income or capitalized on the consolidated balance sheet as a regulatory asset.

Segment Reporting (Tables)

Segment Reporting (Tables)	6 Months Ended
	Jun. 30, 2020
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	NSP-Wisconsin's segment information for the three and six months ended June 30: Three Months Ended June 30 (Millions of Dollars) 2020 2019 Regulated Electric Operating revenues (a) $ 199.3 $ 207.9 Intersegment revenues 0.1 0.1 Total operating revenue $ 199.4 $ 208.0 Net income 16.3 10.9 Regulated Natural Gas Operating revenues $ 19.0 $ 20.9 Intersegment revenues 0.2 — Total operating revenue $ 19.2 $ 20.9 Net loss (2.9) (1.3) All Other Operating revenues $ 0.2 $ 0.1 Net loss (1.3) (1.0) Consolidated Total Operating revenues (a) $ 218.8 $ 229.0 Reconciling eliminations (0.3) (0.1) Total operating revenues $ 218.5 $ 228.9 Net income 12.1 8.6 (a) Operating revenues include $41.5 million and $43.5 million of affiliate electric revenue for the three months ended June 30, 2020 and 2019, respectively. Six Months Ended June 30 (Millions of Dollars) 2020 2019 Regulated Electric Operating revenues (a) $ 411.1 $ 422.9 Intersegment revenues 0.2 0.2 Total operating revenue $ 411.3 $ 423.1 Net income 41.0 24.1 Regulated Natural Gas Operating revenues $ 64.2 $ 82.0 Intersegment revenues 0.3 0.2 Total operating revenues $ 64.5 $ 82.2 Net income 6.0 9.2 All Other Operating revenues $ 0.2 $ 0.2 Net loss (1.3) (0.7) Consolidated Total Operating revenues (a) $ 476.0 $ 505.5 Reconciling eliminations (0.5) (0.4) Total operating revenues $ 475.5 $ 505.1 Net income 45.7 32.6 (a) Operating revenues include $82.4 million and $87.6 million of affiliate electric revenue for the six months ended June 30, 2020 and 2019, respectively.	[1]
[1]	Operating revenues include $41.5 million and $43.5 million of affiliate electric revenue for the three months ended June 30, 2020 and 2019, respectively.

Accounting Pronouncements Accou

Accounting Pronouncements Accounting Pronouncements (Details) - USD ($)	Jan. 01, 2020	Jun. 30, 2020
Credit Losses, Topic 326 (ASC Topic 326)		$ 100,000
Retained Earnings
Credit Losses, Topic 326 (ASC Topic 326)	$ 100,000	$ 100,000

Selected Balance Sheet Data, Ac

Selected Balance Sheet Data, Accounts Receivable (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Accounts Receivable, Net
Accounts receivable	$ 69.5	$ 64.7
Less allowance for bad debts	(6.1)	(5.5)
Accounts receivable, net	$ 63.4	$ 59.2

Selected Balance Sheet Data, In

Selected Balance Sheet Data, Inventory (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Public Utilities, Inventory [Line Items]
Total Inventories	$ 13.4	$ 16
Materials and supplies
Public Utilities, Inventory [Line Items]
Inventories	7.3	6.8
Fuel
Public Utilities, Inventory [Line Items]
Inventories	4.1	4
Natural gas
Public Utilities, Inventory [Line Items]
Inventories	$ 2	$ 5.2

Selected Balance Sheet Data, Pr

Selected Balance Sheet Data, Property, Plant and Equipment (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 3,769.9	$ 3,674.4
Less accumulated depreciation	(1,353.1)	(1,315)
Property, plant and equipment, net	2,416.8	2,359.4
Electric plant
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	3,070.6	3,024.6
Natural gas plant
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	375.2	365.5
Common and other property
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	203.7	201.5
Construction work in progress
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 120.4	$ 82.8

Borrowings and Other Financin_3

Borrowings and Other Financing Instruments, Commercial Paper (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Short-term Debt [Line Items]
Amount outstanding at period end	$ 0	$ 65,000,000
Payable to Affiliates
Short-term Debt [Line Items]
Notes Payable, Related Parties, Current	0	0
Commercial Paper
Short-term Debt [Line Items]
Borrowing limit	150,000,000	150,000,000
Amount outstanding at period end	0	65,000,000
Average amount outstanding	41,000,000	51,000,000
Maximum amount outstanding	$ 91,000,000	$ 93,000,000
Weighted average interest rate, computed on a daily basis	1.04%	2.38%
Weighted average interest rate at period end		1.97%

Borrowings and Other Financin_4

Borrowings and Other Financing Instruments, Letters of Credit (Details) - USD ($)	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Line of Credit Facility [Line Items]
Line of Credit Facility, Expiration Period	1 year
Amount outstanding at period end	$ 0	$ 65,000,000
Credit Facility
Line of Credit Facility [Line Items]
Long-term Line of Credit	$ 0	$ 0

Borrowings and Other Financin_5

Borrowings and Other Financing Instruments, Credit Facility (Details) - Credit Facility - USD ($)		Jun. 30, 2020	Dec. 31, 2019
Line of Credit Facility [Line Items]
Credit Facility	[1]	$ 150,000,000
Outstanding	[2]	0
Available		150,000,000
Direct advances on the credit facility outstanding		$ 0	$ 0
[1]	This credit facility expires in June 2024.
[2]	Includes outstanding commercial paper.

Borrowings and Other Financin_6

Borrowings and Other Financing Instruments (Details) - Series Due May 1, 2051 [Domain] - Bonds [Member]	May 26, 2020USD ($)
Debt Disclosure [Abstract]
Debt Instrument, Face Amount	$ 100,000,000
Short-term Debt [Line Items]
Debt Instrument, Face Amount	$ 100,000,000
NSP-Wisconsin [Member]
Debt Disclosure [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	305.00%
Short-term Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	305.00%

Revenues (Details)

Revenues (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	May 26, 2020
Series Due May 1, 2051 [Domain] | Bonds [Member]
Disaggregation of Revenue [Line Items]
Debt Instrument, Face Amount					$ 100,000,000
Series Due May 1, 2051 [Domain] | Bonds [Member] | NSP-Wisconsin [Member]
Disaggregation of Revenue [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					305.00%
Total revenues
Disaggregation of Revenue [Line Items]
Total revenues	$ 218,500,000	$ 228,900,000	$ 475,500,000	$ 505,100,000
Regulated Electric | Total revenues
Disaggregation of Revenue [Line Items]
Total revenues	199,300,000	207,900,000	411,100,000	422,900,000
Regulated Natural Gas | Total revenues
Disaggregation of Revenue [Line Items]
Total revenues	19,000,000	20,900,000	64,200,000	82,000,000
All Other | Total revenues
Disaggregation of Revenue [Line Items]
Total revenues	200,000	100,000	200,000	200,000
Total revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	215,100,000	225,300,000	468,300,000	497,900,000
Total revenue from contracts with customers | Regulated Electric
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	196,400,000	204,900,000	404,800,000	416,900,000
Total revenue from contracts with customers | Regulated Natural Gas
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	18,500,000	20,300,000	63,300,000	80,800,000
Total revenue from contracts with customers | All Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	200,000	100,000	200,000	200,000
Retail
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	172,400,000	180,800,000	383,400,000	407,700,000
Retail | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	70,200,000	64,900,000	159,700,000	165,900,000
Retail | Commercial and industrial (C&I)
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	100,000,000	113,700,000	219,900,000	238,000,000
Retail | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,200,000	2,200,000	3,800,000	3,800,000
Retail | Regulated Electric
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	154,800,000	161,300,000	321,800,000	328,700,000
Retail | Regulated Electric | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	59,600,000	54,100,000	124,600,000	121,500,000
Retail | Regulated Electric | Commercial and industrial (C&I)
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	93,200,000	105,100,000	193,600,000	203,600,000
Retail | Regulated Electric | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,000,000	2,100,000	3,600,000	3,600,000
Retail | Regulated Natural Gas
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	17,400,000	19,400,000	61,400,000	78,800,000
Retail | Regulated Natural Gas | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10,600,000	10,800,000	35,100,000	44,400,000
Retail | Regulated Natural Gas | Commercial and industrial (C&I)
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,800,000	8,600,000	26,300,000	34,400,000
Retail | Regulated Natural Gas | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Retail | All Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	200,000	100,000	200,000	200,000
Retail | All Other | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Retail | All Other | Commercial and industrial (C&I)
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Retail | All Other | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	200,000	100,000	200,000	200,000
Interchange [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	41,500,000	43,500,000	82,400,000	87,600,000
Interchange [Member] | Regulated Electric
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	41,500,000	43,500,000	82,400,000	87,600,000
Interchange [Member] | Regulated Natural Gas
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Interchange [Member] | All Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,200,000	1,000,000	2,500,000	2,600,000
Other | Regulated Electric
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	100,000	100,000	600,000	600,000
Other | Regulated Natural Gas
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,100,000	900,000	1,900,000	2,000,000
Other | All Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Alternative revenue and other
Disaggregation of Revenue [Line Items]
Alternative revenue and other	3,400,000	3,600,000	7,200,000	7,200,000
Alternative revenue and other | Regulated Electric
Disaggregation of Revenue [Line Items]
Alternative revenue and other	2,900,000	3,000,000	6,300,000	6,000,000
Alternative revenue and other | Regulated Natural Gas
Disaggregation of Revenue [Line Items]
Alternative revenue and other	500,000	600,000	900,000	1,200,000
Alternative revenue and other | All Other
Disaggregation of Revenue [Line Items]
Alternative revenue and other	$ 0	$ 0	$ 0	$ 0

Income Taxes (Details)

Income Taxes (Details) - USD ($)		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Income Tax Examination [Line Items]
Unrecognized Tax Benefits, Income Tax Penalties Accrued		$ 0		$ 0
Net Deferred Tax Liability associated with the Unrecognized Tax Benefit Amounts and Related NOLs and Tax Credit Carryforwards		$ (1,300,000)		$ (1,200,000)
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%	21.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent		6.20%	6.20%
Effective Income Tax Rate Reconciliation, Other Regulatory Items, Percent	[1]	(18.40%)	(0.50%)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amortization, Percent		(12.50%)	0.00%
Regulatory difference - tax credits and tax credit and NOL allowances (net)		(1.70%)	(1.00%)
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent		0.80%	0.30%
Effective Income Tax Rate Reconciliation, Percent		(4.60%)	28.20%
Effective Income Tax Rate Reconciliation, Prior Year Income Taxes, Percent		0.00%	2.20%
Tax Audits [Abstract]
Income Tax Credits and Adjustments		$ 0
State Jurisdiction (Wisconsin)
Tax Audits [Abstract]
Potential Tax Adjustments		$ 0
[1]	Regulatory differences for income tax primarily relates to the credit of excess deferred taxes to customers through the average rate assumption method. Income tax benefits associated with the credit of excess deferred credits are offset by corresponding revenue reductions.

Income Taxes Unrecognized Benef

Income Taxes Unrecognized Benefits (Details) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Net Deferred Tax Liability associated with the Unrecognized Tax Benefit Amounts and Related NOLs and Tax Credit Carryforwards	$ (1,300,000)	$ (1,200,000)
Tax Benefits Associated With Nol And Tax Credit Carryforwards	2,100,000	2,200,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	2,600,000	2,600,000
Unrecognized Tax Benefits That Would Not Impact Effective Tax Rate	800,000	800,000
Total unrecognized tax benefit	3,400,000	3,400,000
Decrease in Unrecognized Tax Benefits is Reasonably Possible	1,800,000
Unrecognized Tax Benefits, Income Tax Penalties Accrued	$ 0	$ 0

Interest Rate Derivatives (Deta

Interest Rate Derivatives (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Interest Rate Swap
Derivative [Line Items]
Derivative Liability, Notional Amount	$ 0	$ 0

Fair Value of Financial Asset_3

Fair Value of Financial Assets and Liabilities Commodity Derivatives (Details) - MMBTU MMBTU in Millions		Jun. 30, 2020	Dec. 31, 2019
Natural Gas Commodity [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	[1],[2]	0.4	0.1
[1]	Amounts are not reflective of net positions in the underlying commodities.
[2]	Notional amounts for options are included on a gross basis, but are weighted for the probability of exercise.

Impact of Derivative Activity o

Impact of Derivative Activity on Income and Accumulated Other Comprehensive Loss (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Financial Impact of Qualifying Fair Value Hedges on Earnings [Abstract]
Derivative instruments designated as fair value hedges	$ 0	$ 0	$ 0	$ 0
Other Derivative Instruments | Natural Gas Commodity
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax fair value gains (losses) recognized during the period in regulatory (assets) and liabilities			100,000
Pre-tax (gains) losses reclassified into income during the period from regulatory assets and (liabilities)	$ 0	$ 0	$ (900,000)	$ (200,000)

Recurring Fair Value Measuremen

Recurring Fair Value Measurements (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Prepayments and other	$ 4.9	$ 4.6
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Natural Gas Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross	0.2	0.5	[1]
Netting	0	0	[1],[2]
Derivative Asset, Net	0.2	0.5	[1],[3]
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Natural Gas Commodity | Level 1
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross	0	0	[1]
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Natural Gas Commodity | Level 2
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross	0.2	0.5	[1]
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Natural Gas Commodity | Level 3
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross	$ 0	$ 0	[1]
[1]	.
[2]	NSP-Wisconsin nets derivative instruments and related collateral in its consolidated balance sheet when supported by a legally enforceable master netting agreement, and all derivative instruments and related collateral amounts were subject to master netting agreements at June 30, 2020 and Dec. 31, 2019. The counterparty netting amounts presented exclude settlement receivables and payables and non-derivative amounts that may be subject to the same master netting agreements.
[3]	Included in prepayments and other current assets balance of $4.9 million at June 30, 2020 and $4.6 million at Dec. 31, 2019 in the consolidated balance sheets.

Fair Value of Long-Term Debt (D

Fair Value of Long-Term Debt (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Carrying Amount	$ 906	$ 808
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	$ 1,124.3	$ 924.3

Benefit Plans and Other Postr_3

Benefit Plans and Other Postretirement Benefits (Details) $ in Millions		1 Months Ended	3 Months Ended		6 Months Ended
		Jan. 31, 2020USD ($)Plan	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)
Pension Plan [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost			$ 1.2	$ 1.1	$ 2.3	$ 2.2
Interest cost (a)	[1]		1.2	1.4	2.4	2.9
Expected return on plan assets (a)	[1]		(2.1)	(2)	(4.2)	(4.2)
Amortization of prior service cost (credit) (a)	[1]		0	0	0	0
Amortization of net loss (a)	[1]		1.2	1.1	2.4	2.2
Net periodic benefit cost			1.5	1.6	2.9	3.1
Defined Benefit Plan Credits Not Recognized Due To Effects of Regulation			1.8	0	3.7	0.2
Net benefit cost recognized for financial reporting			3.3	1.6	6.6	3.3
Contributions to pension plans		$ 6.7
Pension Plan [Member] | Parent Company [Member]
Components of Net Periodic Benefit Cost [Abstract]
Contributions to pension plans		$ 150
Number of Xcel Energy's pension plans to which contributions were made | Plan		4
Other Postretirement Benefits Plan [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost			0	0	0	0
Interest cost (a)	[1]		0.1	0.1	0.2	0.3
Expected return on plan assets (a)	[1]		0	0	0	0
Amortization of prior service cost (credit) (a)	[1]		(0.1)	(0.1)	(0.1)	(0.2)
Amortization of net loss (a)	[1]		0.1	0.1	0.1	0.1
Net periodic benefit cost			0.1	0.1	0.2	0.2
Defined Benefit Plan Credits Not Recognized Due To Effects of Regulation			0	0
Net benefit cost recognized for financial reporting			$ 0.1	$ 0.1	$ 0.2	$ 0.2
[1]	The components of net periodic cost other than the service cost component are included in the line item “other expense, net” in the consolidated statement of income or capitalized on the consolidated balance sheet as a regulatory asset.

Commitments and Contingencies G

Commitments and Contingencies Gas Trading Litigation (Details)	Jun. 30, 2020
Gas Trading Litigation
Loss Contingencies [Line Items]
Loss Contingency, Pending Claims, Number	2

MISO ROE Complaints (Details)

MISO ROE Complaints (Details) - NSP Minnesota and NSP Wisconsin [Member] [Member] - FERC Proceeding, MISO ROE Complaint - Federal Energy Regulatory Commission (FERC)	1 Months Ended		3 Months Ended	39 Months Ended
	Feb. 28, 2015	Nov. 30, 2013	Mar. 31, 2017	Dec. 31, 2019	Jun. 30, 2020
Rate Matters [Abstract]
Public Utilities, Base Return On Equity Charged To Customers Through Transmission Formula Rates	12.38%	12.38%
Public Utilities, ROE Applicable To Transmission Formula Rates In The MISO Region, Recommended By Third Parties	8.67%	9.15%
Public Utilities, ROE Applicable To Transmission Formula Rates In The MISO Region, Approved			10.32%
Public Utilities, ROE Applicable To Transmission Formula Rates In The MISO Region, with RTO Adder, Approved			10.82%
Public Utilities, ROE developed with new approach				9.88%
Public Utilities, ROE developed with new approach, with RTO Adder, Approved				10.38%
Public Utilities, ROE New Base, Complaint Number 1				10.02%
Maximum [Member]
Rate Matters [Abstract]
basis points					100
Minimum [Member]
Rate Matters [Abstract]
basis points					50

MGP, Landfill and Disposal Site

MGP, Landfill and Disposal Sites (Details) $ in Millions	6 Months Ended
	Jun. 30, 2020USD ($)	Dec. 31, 2019USD ($)
Ashland MGP Site
Ashland Manufactured Gas Plant (MGP) Site [Abstract]
Current Cost Estimate for Site Remediation	$ 199.1
Accrual for Environmental Loss Contingencies, Gross	$ 21.4	$ 23.2
Carrying cost percentage to be applied to unamortized regulatory asset	3.00%
Other MGP, Landfill, or Disposal Sites [Domain]
Ashland Manufactured Gas Plant (MGP) Site [Abstract]
Number of identified MGP sites under current investigation and/or remediation	2

Segment Information (Details)

Segment Information (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Net income		$ 12.1	$ 8.6	$ 45.7	$ 32.6
Natural gas		19	20.9	64.2	82
Unregulated Operating Revenue		0.2	0.1	0.2	0.2
Regulated and Unregulated Operating Revenue		218.5	228.9	475.5	505.1
Affiliate Revenue		41.5	43.5	82.4	87.6
Electricity, US Regulated [Member]
Segment Reporting Information [Line Items]
Revenues Including Intersegment Revenues		199.4	208	411.3	423.1
Net income		16.3	10.9	41	24.1
Natural Gas, US Regulated [Member]
Segment Reporting Information [Line Items]
Revenues Including Intersegment Revenues		19.2	20.9	64.5	82.2
Net income		(2.9)	(1.3)	6	9.2
All Other
Segment Reporting Information [Line Items]
Net income		(1.3)	(1)	(1.3)	(0.7)
Total revenues
Segment Reporting Information [Line Items]
Regulated and Unregulated Operating Revenue	[1]	218.8	229	476	505.5
Total revenues | Electricity, US Regulated [Member]
Segment Reporting Information [Line Items]
Regulated Operating Revenue, Electric	[1]	199.3	207.9	411.1	422.9
Total revenues | Natural Gas, US Regulated [Member]
Segment Reporting Information [Line Items]
Natural gas		19	20.9	64.2	82
Total revenues | All Other
Segment Reporting Information [Line Items]
Unregulated Operating Revenue		0.2	0.1	0.2	0.2
Intersegment Eliminations
Segment Reporting Information [Line Items]
Regulated and Unregulated Operating Revenue		(0.3)	(0.1)	(0.5)	(0.4)
Intersegment Eliminations | Electricity, US Regulated [Member]
Segment Reporting Information [Line Items]
Regulated Operating Revenue, Electric		0.1	0.1	0.2	0.2
Intersegment Eliminations | Natural Gas, US Regulated [Member]
Segment Reporting Information [Line Items]
Natural gas		$ 0.2	$ 0	$ 0.3	$ 0.2
[1]	Operating revenues include $41.5 million and $43.5 million of affiliate electric revenue for the three months ended June 30, 2020 and 2019, respectively.