Cover Page
Cover Page - USD ($) | 12 Months Ended | ||
Dec. 31, 2023 | Feb. 21, 2024 | Jun. 30, 2023 | |
Cover [Abstract] | |||
Document Type | 10-K | ||
Document Annual Report | true | ||
Document Period End Date | Dec. 31, 2023 | ||
Document Transition Report | false | ||
Entity File Number | 001-03140 | ||
Entity Incorporation, State or Country Code | WI | ||
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 | 737-2625 | ||
Entity Well-known Seasoned Issuer | Yes | ||
Entity Voluntary Filers | No | ||
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 | ||
ICFR Auditor Attestation Flag | false | ||
Entity Shell Company | false | ||
Entity Common Stock, Shares Outstanding | 933,000 | ||
Entity Registrant Name | NORTHERN STATES POWER CO | ||
Entity Central Index Key | 0000072909 | ||
Current Fiscal Year End Date | --12-31 | ||
Document Fiscal Year Focus | 2023 | ||
Document Fiscal Period Focus | FY | ||
Amendment Flag | false | ||
Entity Public Float | $ 0 | ||
Document Financial Statement Error Correction [Flag] | false |
Audit Information
Audit Information | 12 Months Ended |
Dec. 31, 2023 | |
Auditor [Line Items] | |
Auditor Name | DELOITTE & TOUCHE LLP |
Auditor Location | Minneapolis, Minnesota |
Auditor Firm ID | 34 |
Accounting Pronouncements
Accounting Pronouncements | 12 Months Ended |
Dec. 31, 2023 | |
Accounting Standards Update and Change in Accounting Principle [Abstract] | |
Accounting Pronouncements | Recently Issued Segment Reporting — In November 2023, the FASB issued ASU 2023-07 – Segment Reporting (Topic 280) – Improvements to Reportable Segment Disclosures , which extends the existing requirements for annual disclosures to quarterly periods, and requires that both annual and quarterly disclosures present segment expenses using line items consistent with information regularly provided to the chief operating decision maker. The ASU is effective for annual periods beginning after Dec. 15, 2023 and quarterly periods beginning after Dec. 15, 2024, and NSP-Wisconsin does not expect implementation of the new disclosure guidance to have a material impact to its consolidated financial statements. Income Taxes — In December 2023, the FASB issued ASU 2023-09 – Income Taxes (Topic 740) – Improvements to Income Tax Disclosures |
CONSOLIDATED STATEMENTS OF INCO
CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | |
Operating revenues | |||
Electric, non-affiliates | $ 815 | $ 800 | $ 733 |
Electric, affiliates | 204 | 202 | 189 |
Natural gas | 157 | 198 | 182 |
Other | 1 | 1 | 1 |
Total operating revenues | 1,177 | 1,201 | 1,105 |
Operating expenses | |||
Electric fuel and purchased power, non-affiliates | 14 | 17 | 20 |
Purchased power, affiliates | 408 | 446 | 408 |
Cost of natural gas sold and transported | 80 | 116 | 117 |
Operating and maintenance expenses | 239 | 223 | 198 |
Conservation program expenses | 13 | 13 | 13 |
Depreciation and amortization | 170 | 158 | 147 |
Taxes (other than income taxes) | 34 | 31 | 28 |
Workforce Reduction Expense | 5 | 0 | 0 |
Total operating expenses | 963 | 1,004 | 931 |
Operating income | 214 | 197 | 174 |
Other Income and Expenses [Abstract] | |||
Other income (expense), net | 2 | (2) | (1) |
Allowance for funds used during construction — equity | 10 | 7 | 5 |
Interest charges and financing costs | |||
Interest charges — includes other financing costs of $2, $1 and $1, respectively | 54 | 45 | 42 |
Allowance for funds used during construction — debt | (4) | (3) | (2) |
Total interest charges and financing costs | 50 | 42 | 40 |
Income before income taxes | 176 | 160 | 138 |
Income tax expense | 40 | 35 | 30 |
Net income | $ 136 | $ 125 | $ 108 |
CONSOLIDATED STATEMENTS OF IN_2
CONSOLIDATED STATEMENTS OF INCOME (Parenthetical) - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | |
Interest charges and financing costs | |||
Other financing costs | $ 2 | $ 1 | $ 1 |
CONSOLIDATED STATEMENTS OF CASH
CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | |
Operating activities | |||
Net income | $ 136 | $ 125 | $ 108 |
Adjustments to reconcile net income to cash provided by operating activities: | |||
Depreciation and amortization | 173 | 159 | 148 |
Deferred income taxes | (12) | (2) | 9 |
Allowance for equity funds used during construction | (10) | (7) | (5) |
Provision for bad debts | 4 | 4 | 4 |
Changes in operating assets and liabilities: | |||
Accounts receivable | (4) | (13) | (5) |
Accrued unbilled revenues | 11 | (5) | (16) |
Inventories | (6) | (14) | (12) |
Other current assets | 21 | (20) | (4) |
Accounts payable | (6) | 5 | 8 |
Net regulatory assets and liabilities | 44 | 18 | (41) |
Other current liabilities | 2 | 16 | 2 |
Pension and other employee benefit obligations | 0 | (4) | (9) |
Other, net | 4 | (5) | (1) |
Net cash provided by operating activities | 357 | 257 | 186 |
Investing activities | |||
Capital/construction expenditures | (456) | (353) | (264) |
Investments In Utility Money Pool Arrangement | (153) | (100) | (71) |
Repayments From Utility Money Pool Arrangement | 153 | 100 | 71 |
Net cash used in investing activities | (456) | (353) | (264) |
Financing activities | |||
Proceeds from (repayments of) short-term borrowings, net | 13 | (35) | 64 |
Borrowings under money pool arrangement | 163 | 591 | 358 |
Repayments under money pool arrangement | (163) | (591) | (358) |
Proceeds from issuance of long-term debt | 124 | 99 | 99 |
Repayments of long-term debt | 0 | 0 | (19) |
Capital contributions from parent | 75 | 114 | 46 |
Dividends paid to parent | (109) | (91) | (103) |
Net cash provided by financing activities | 103 | 87 | 87 |
Net change in cash, cash equivalents and restricted cash | 4 | (9) | 9 |
Cash, cash equivalents and restricted cash at beginning of period | 2 | 11 | 2 |
Cash, cash equivalents and restricted cash at end of period | 6 | 2 | 11 |
Supplemental disclosure of cash flow information: | |||
Cash paid for interest (net of amounts capitalized) | (47) | (39) | (38) |
Cash paid for income taxes, net | (40) | (32) | (22) |
Other Noncash Investing and Financing Items [Abstract] | |||
Supplemental disclosure of non-cash investing and financing transactions: | 31 | 54 | 43 |
Inventory transfers to plant, property and equipment | 17 | 1 | 1 |
Allowance for Funds Used During Construction, Investing Activities | $ 10 | $ 7 | $ 5 |
CONSOLIDATED BALANCE SHEETS
CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022 |
Current assets | ||
Cash and cash equivalents | $ 6 | $ 2 |
Accounts receivable, net | 89 | 84 |
Accrued unbilled revenues | 63 | 74 |
Other receivables | 0 | 19 |
Inventories | 29 | 39 |
Regulatory assets | 24 | 44 |
Prepaid taxes | 28 | 27 |
Prepayments and other | 6 | 11 |
Total current assets | 245 | 300 |
Property, Plant and Equipment, Net | 3,237 | 2,914 |
Other assets | ||
Regulatory assets | 185 | 193 |
Other | 3 | 3 |
Total other assets | 188 | 196 |
Total assets | 3,670 | 3,410 |
Current liabilities | ||
Long-Term Debt and Lease Obligation, Current | 200 | 0 |
Short-term debt | 60 | 47 |
Accounts payable | 64 | 92 |
Accounts payable to affiliates | 21 | 19 |
Dividends payable to parent | 25 | 23 |
Regulatory liabilities | 42 | 21 |
Taxes accrued | 16 | 13 |
Accrued interest | 13 | 12 |
Other | 23 | 28 |
Total current liabilities | 464 | 255 |
Deferred credits and other liabilities | ||
Deferred income taxes | 330 | 333 |
Deferred investment tax credits | 5 | 5 |
Regulatory liabilities | 407 | 383 |
Customer advances | 25 | 23 |
Pension and employee benefit obligations | 27 | 23 |
Other | 35 | 43 |
Total deferred credits and other liabilities | 829 | 810 |
Commitments and contingencies | ||
Capitalization | ||
Long-term debt | 1,011 | 1,086 |
Common stock — 1,000,000 shares authorized of $100 par value; 933,000 shares outstanding at Dec. 31, 2023 and Dec. 31, 2022, respectively | 93 | 93 |
Additional paid in capital | 843 | 761 |
Retained earnings | 430 | 405 |
Total common stockholder's equity | 1,366 | 1,259 |
Total liabilities and equity | $ 3,670 | $ 3,410 |
CONSOLIDATED BALANCE SHEETS (Pa
CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares | Dec. 31, 2023 | Dec. 31, 2022 |
Statement of Financial Position [Abstract] | ||
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 |
CONSOLIDATED STATEMENTS OF COMM
CONSOLIDATED STATEMENTS OF COMMON STOCKHOLDER'S EQUITY - USD ($) $ in Millions | Total | Common stock | Additional Paid In Capital | Retained Earnings |
Beginning Balance at Dec. 31, 2020 | $ 1,068 | $ 93 | $ 605 | $ 370 |
Balance (in shares) at Dec. 31, 2020 | 933,000 | |||
Increase (Decrease) in Stockholder's Equity | ||||
Net income | 108 | 108 | ||
Dividends, Common Stock, Cash | (110) | (110) | ||
Contribution of capital by parent | 37 | 37 | ||
Ending Balance at Dec. 31, 2021 | 1,103 | $ 93 | 642 | 368 |
Balance (in shares) at Dec. 31, 2021 | 933,000 | |||
Increase (Decrease) in Stockholder's Equity | ||||
Net income | 125 | 125 | ||
Dividends, Common Stock, Cash | (88) | (88) | ||
Contribution of capital by parent | 119 | 119 | ||
Ending Balance at Dec. 31, 2022 | $ 1,259 | $ 93 | 761 | 405 |
Balance (in shares) at Dec. 31, 2022 | 933,000 | 933,000 | ||
Increase (Decrease) in Stockholder's Equity | ||||
Net income | $ 136 | 136 | ||
Dividends, Common Stock, Cash | (111) | (111) | ||
Contribution of capital by parent | 82 | 82 | ||
Ending Balance at Dec. 31, 2023 | $ 1,366 | $ 93 | $ 843 | $ 430 |
Balance (in shares) at Dec. 31, 2023 | 933,000 | 933,000 |
Summary of Significant Accounti
Summary of Significant Accounting Policies | 12 Months Ended |
Dec. 31, 2023 | |
Accounting Policies [Abstract] | |
Summary of Significant Accounting Policies | General — NSP-Wisconsin is engaged in the regulated generation, transmission, distribution and sale of electricity and the regulated purchase, transportation, distribution and sale of natural gas. NSP-Wisconsin’s consolidated financial statements include its wholly-owned subsidiaries and VIEs for which it is the primary beneficiary. In the consolidation process, all intercompany transactions and balances are eliminated. NSP-Wisconsin has investments in certain transmission facilities jointly owned with nonaffiliated utilities. NSP-Wisconsin’s proportionate share of jointly owned facilities is recorded as property, plant and equipment on the consolidated balance sheets and NSP-Wisconsin’s proportionate share of operating costs associated with these facilities is included in its consolidated statements of income. NSP-Wisconsin’s consolidated financial statements are presented in accordance with GAAP. All of NSP-Wisconsin’s underlying accounting records also conform to the FERC uniform system of accounts or to systems required by various state regulatory commissions. Certain amounts in the consolidated financial statements or notes have been reclassified for comparative purposes; however, such reclassifications did not affect net income, total assets, liabilities, equity or cash flows. NSP-Wisconsin has evaluated events occurring after Dec. 31, 2023 up to the date of issuance of these consolidated financial statements. These statements contain all necessary adjustments and disclosures resulting from that evaluation. Use of Estimates — NSP-Wisconsin uses estimates based on the best information available to record transactions and balances resulting from business operations. Estimates are used for items such as plant depreciable lives or potential disallowances, AROs, certain regulatory assets and liabilities, tax provisions, uncollectible amounts, environmental costs, unbilled revenues, jurisdictional fuel and energy cost allocations and actuarially determined benefit costs. Recorded estimates are revised when better information becomes available or actual amounts can be determined. Revisions can affect operating results. Regulatory Accounting — NSP-Wisconsin accounts for income and expense items in accordance with accounting guidance for regulated operations. Under this guidance: • Certain costs, which would otherwise be charged to expense or other comprehensive income, are deferred as regulatory assets based on the expected ability to recover the costs in future rates. • Certain credits, which would otherwise be reflected as income or other comprehensive income, are deferred as regulatory liabilities based on the expectation the amounts will be returned to customers in future rates or because the amounts were collected in rates prior to the costs being incurred. Estimates and assumptions for recovery of deferred costs and refund of deferred credits are based on specific ratemaking decisions, precedent or other available information. Regulatory assets and liabilities are amortized consistent with the treatment in the rate setting process. If changes in the regulatory environment occur, NSP-Wisconsin may no longer be eligible to apply this accounting treatment and may be required to eliminate regulatory assets and liabilities. Such changes could have a material effect on NSP-Wisconsin’s results of operations, financial condition and cash flows. See Note 4 for further information. Income Taxes — NSP-Wisconsin accounts for income taxes using the asset and liability method, which requires recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements. Income taxes are deferred for all temporary differences between pretax financial and taxable income and between the book and tax bases of assets and liabilities utilizing rates that are scheduled to be in effect when the temporary differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in the period that includes the enactment date. Utility rate regulation has resulted in the recognition of regulatory assets and liabilities related to income taxes. The effects of NSP-Wisconsin’s tax rate changes are generally subject to a normalization method of accounting. Therefore, the revaluation of most of its net deferred taxes upon a tax rate reduction results in the establishment of a net regulatory liability, refundable to utility customers over the remaining life of the related assets. NSP-Wisconsin anticipates that a tax rate increase would predominantly result in the establishment of a regulatory asset, subject to an evaluation of whether future recovery is expected. Reversal of certain temporary differences are accounted for as current income tax expense due to the effects of past regulatory practices when deferred taxes were not required to be recorded due to the use of flow through accounting for ratemaking purposes. Tax credits are recorded when earned unless there is a requirement to defer the benefit and amortize over the book depreciable lives of related property. The requirement to defer and amortize these credits specifically applies to certain federal ITCs, as determined by tax regulations and NSP-Wisconsin tax elections. For tax credits otherwise eligible to be recognized when earned, NSP-Wisconsin considers the impact of rate regulation to determine if these credits and related adjustments should be deferred as regulatory assets or liabilities. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that some portion or all of the deferred tax asset will not be realized. NSP-Wisconsin measures and discloses uncertain tax positions that it has taken or expects to take in its income tax returns. A tax position is recognized in the consolidated financial statements when it is more likely than not that the position will be sustained upon examination based on the technical merits of the position. Recognition of changes in uncertain tax positions are reflected as a component of income tax expense. Interest and penalties related to income taxes are reported within Other income (expense), net or interest charges in the consolidated statements of income. Xcel Energy Inc. and its subsidiaries, including NSP-Wisconsin file consolidated federal income tax returns as well as consolidated or separate state income tax returns. Federal income taxes paid by Xcel Energy Inc. are allocated to its subsidiaries based on separate company computations. A similar allocation is made for state income taxes paid by Xcel Energy Inc. in connection with consolidated state filings. Xcel Energy Inc. also allocates its own income tax benefits to its direct subsidiaries. See Note 7 for further information. Property, Plant and Equipment and Depreciation in Regulated Operations — Property, plant and equipment is stated at original cost. The cost of plant includes direct labor and materials, contracted work, overhead costs and AFUDC. The cost of plant retired is charged to accumulated depreciation and amortization. Amounts recovered in rates for future removal costs are recorded as regulatory liabilities. Significant additions or improvements extending asset lives are capitalized, while repairs and maintenance costs and replacement of items determined to be less than a unit of property are charged to expense as incurred. Property, plant and equipment is tested for impairment when it is determined that the carrying value of the assets may not be recoverable. A loss is recognized in the current period if it becomes probable that part of a cost of a plant under construction or recently completed plant will be disallowed for recovery from customers and a reasonable estimate of the disallowance can be made. For investments in property, plant and equipment that are abandoned and not expected to go into service, incurred costs and related deferred tax amounts are compared to the discounted estimated future rate recovery, and a loss is recognized, if necessary. Depreciation expense is recorded using the straight-line method over the plant’s commission approved useful life. Actuarial life studies are performed and submitted to the state and federal commissions for review. Upon acceptance by the various commissions, the resulting lives and net salvage rates are used to calculate depreciation. Plant removal costs are typically recognized at the amounts recovered in rates as authorized by the applicable regulator. Accumulated removal costs are reflected in the consolidated balance sheet as a regulatory liability. Depreciation expense, expressed as a percentage of average depreciable property, was approximately 3.6% in 2023, 2022 and 2021. See Note 3 for further information. AROs — NSP-Wisconsin records AROs as a liability in the period incurred (if fair value can be reasonably estimated), with the offsetting/associated costs capitalized as a long-lived asset. The liability is generally increased over time by applying the effective interest method of accretion and the capitalized costs are typically depreciated over the useful life of the long-lived asset. Changes resulting from revisions to timing or amounts of expected asset retirement cash flows are recognized as an increase or a decrease in the ARO. See Note 10 for further information. Benefit Plans and Other Postretirement Benefits — NSP-Wisconsin maintains pension and postretirement benefit plans for eligible employees. Recognizing the cost of providing benefits and measuring the projected benefit obligation of these plans requires management to make various assumptions and estimates. Certain unrecognized actuarial gains and losses and unrecognized prior service costs or credits are deferred as regulatory assets and liabilities, rather than recorded as other comprehensive income, based on regulatory recovery mechanisms. See Note 9 for further information. Environmental Costs — Environmental costs are recorded when it is probable NSP-Wisconsin is liable for remediation costs and the amount can be reasonably estimated. Costs are deferred as a regulatory asset if it is probable the costs will be recovered from customers in future rates. Otherwise, the costs are expensed. For certain environmental costs related to facilities currently in use, such as for emission-control equipment, the cost is capitalized and depreciated over the life of the plant. Estimated remediation costs are regularly adjusted as estimates are revised and remediation is performed. If other participating potentially responsible parties exist and acknowledge their potential involvement with a site, costs are estimated and recorded only for NSP-Wisconsin’s expected share of the cost. Estimated future expenditures to restore sites are treated as a capitalized cost of plant retirement. The depreciation expense levels recoverable in rates include a provision for removal expenses. Removal costs recovered in rates before the related costs are incurred are classified as a regulatory liability. See Note 10 for further information. Revenue from Contracts with Customers — Performance obligations related to the sale of energy are satisfied as energy is delivered to customers. NSP-Wisconsin recognizes revenue that corresponds to the price of the energy delivered to the customer. The measurement of energy sales to customers is generally based on the reading of their meters, which occurs systematically throughout the month. At the end of each month, amounts of energy delivered to customers since the date of the last meter reading are estimated, and the corresponding unbilled revenue is recognized. A separate financing component of collections from customers is not recognized as contract terms are short-term in nature. Revenues are net of any excise or sales taxes or fees. NSP-Wisconsin has various rate-adjustment mechanisms that provide for the recovery of natural gas, electric fuel and purchased energy costs. Cost-adjustment tariffs may increase or decrease the level of revenue collected from customers and are revised periodically for differences between the total amount collected under the clauses and the costs incurred. When applicable, fuel cost over-recoveries (the excess of fuel revenue billed to customers over fuel costs incurred) are deferred as regulatory liabilities and under-recoveries (the excess of fuel costs incurred over fuel revenues billed to customers) are deferred as regulatory assets. NSP-Wisconsin must submit a forward looking fuel cost plan annually for approval by the PSCW. The rules also allow for deferral of any under-recovery or over-recovery of fuel costs in excess of a 2% annual tolerance band, for future rate recovery or refund, subject to PSCW approval. Cash and Cash Equivalents — NSP-Wisconsin considers investments in instruments with a remaining maturity of three months or less at the time of purchase to be cash equivalents. Accounts Receivable and Allowance for Bad Debts — Accounts receivable are stated at the actual billed amount net of an allowance for bad debts. NSP-Wisconsin establishes an allowance for uncollectible receivables based on a policy that reflects its expected exposure to the credit risk of customers. As of Dec. 31, 2023 and 2022, the allowance for bad debts was $9 million. Inventory — Inventory is recorded at the lower of average cost or net realizable value and consisted of the following: (Millions of Dollars) Dec. 31, 2023 Dec. 31, 2022 Inventories Materials and supplies $ 11 $ 8 Fuel 10 11 Natural gas 8 20 Total inventories $ 29 $ 39 Fair Value Measurements — NSP-Wisconsin presents cash equivalents, interest rate derivatives, rabbi trust assets, commodity derivatives, pension and postretirement plan assets at estimated fair values in its consolidated financial statements. For interest rate derivatives, quoted prices based primarily on observable market interest rate curves are used to estimate fair value. For commodity derivatives, the most observable inputs available are generally used to determine the fair value of each contract. In the absence of a quoted price, quoted prices for similar contracts or internally prepared valuation models may be used to determine fair value. For the pension and postretirement plan assets, published trading data and pricing models, generally using the most observable inputs available, are utilized to determine fair value for each security. See Notes 8 and 9 for further information. Derivative Instruments — NSP-Wisconsin uses derivative instruments in connection with its commodity trading activities, and to manage risk associated with changes in interest rates and utility commodity prices, including forward contracts, futures, swaps and options. Derivatives not qualifying for the normal purchases and normal sales exception are recorded on the consolidated balance sheets at fair value as derivative instruments. Classification of changes in fair value for those derivative instruments is dependent on the designation of a qualifying hedging relationship. Changes in fair value of derivative instruments not designated in a qualifying hedging relationship are reflected in current earnings or as a regulatory asset or liability. Classification as a regulatory asset or liability is based on commission approved regulatory recovery mechanisms. Gains or losses on commodity trading transactions are recorded as a component of electric operating revenues. Normal Purchases and Normal Sales — NSP-Wisconsin enters into contracts for purchases and sales of commodities for use in its operations. At inception, contracts are evaluated to determine whether they contain a derivative, and if so, whether they may be exempted from derivative accounting if designated as normal purchases or normal sales. See Note 8 for further information. Other Utility Items AFUDC — AFUDC represents the cost of capital used to finance utility construction activity and is computed by applying a composite financing rate to qualified CWIP. The amount of AFUDC capitalized as a utility construction cost is credited to other nonoperating income (for equity capital) and interest charges (for debt capital). AFUDC amounts capitalized are included in NSP-Wisconsin’s rate base. Alternative Revenue — Certain rate rider mechanisms qualify as alternative revenue programs. These mechanisms arise from instances in which the regulator authorizes a future surcharge in response to past activities or completed events. When certain criteria are met, including expected collection within 24 months, revenue is recognized, which may include incentives and return on rate base items. The mechanisms are revised periodically for differences between total amount collected and the revenue earned, which may increase or decrease the level of revenue collected from customers. Alternative revenues arising from these programs are presented on a gross basis and disclosed separately from revenue from contracts with customers. See Note 6 for further information. Conservation Programs — NSP-Wisconsin participates in and funds conservation programs in its retail jurisdictions to assist customers in conserving energy and reducing peak demand on the electric and natural gas systems. NSP-Wisconsin recovers approved conservation program costs in base rate revenue. For operations in the state of Wisconsin, NSP-Wisconsin is required to contribute 1.2% of its three Emissions Allowances — Emissions allowances are recorded at cost, including broker commission fees. The inventory accounting model is utilized for all emissions allowances and any sales of these allowances are included in electric revenues. RECs — |
Property Plant and Equipment Pr
Property Plant and Equipment Property Plant and Equipment | 12 Months Ended |
Dec. 31, 2023 | |
Property, Plant and Equipment [Abstract] | |
Property, Plant and Equipment Disclosure | Major classes of property, plant and equipment (Millions of Dollars) Dec. 31, 2023 Dec. 31, 2022 Property, plant and equipment, net Electric plant $ 3,845 $ 3,579 Natural gas plant 502 465 Common and other property 278 260 CWIP 252 174 Total property, plant and equipment 4,877 4,478 Less accumulated depreciation (1,640) (1,564) Property, plant and equipment, net $ 3,237 $ 2,914 Joint Ownership of Transmission Facilities Jointly owned assets as of Dec. 31, 2023: (Millions of Dollars, Except Percent Owned) Plant in Service Accumulated Depreciation Percent Owned Electric transmission: La Crosse, WI to Madison, WI $ 178 $ 25 37 % CapX2020 169 39 80 Total (a) $ 347 $ 64 (a) Projects additionally include $1 million in CWIP. NSP-Wisconsin’s share of operating expenses and construction expenditures is included in the applicable utility accounts. Respective owners are responsible for providing their own financing. |
Regulatory Assets and Liabiliti
Regulatory Assets and Liabilities | 12 Months Ended |
Dec. 31, 2023 | |
Regulatory Assets and Liabilities Disclosure [Abstract] | |
Regulatory Assets and Liabilities | Regulatory assets and liabilities are created for amounts that regulators may allow to be collected or may require to be paid back to customers in future electric and natural gas rates. NSP-Wisconsin would be required to recognize the write-off of regulatory assets and liabilities in net income or other comprehensive income if changes in the utility industry no longer allow for the application of regulatory accounting guidance under GAAP. Components of regulatory assets: (Millions of Dollars) See Note(s) Remaining Amortization Period Dec. 31, 2023 Dec. 31, 2022 Regulatory Assets Current Noncurrent Current Noncurrent Pension and retiree medical obligations 9 Various 2 62 2 61 Environmental remediation costs 1, 10 Various $ 13 $ 48 $ 13 $ 63 Recoverable deferred taxes on AFUDC Plant lives — 26 — 20 State commission adjustments Plant lives 1 22 1 22 Net AROs (a) 1, 10 Various — 21 — 18 Deferred natural gas and electric energy/fuel costs 7 Less than one 1 — 23 — Other Various 7 6 5 9 Total regulatory assets $ 24 $ 185 $ 44 $ 193 (a) Includes amounts recorded for future recovery of AROs, less amounts recovered through NSP-Wisconsin’s share of nuclear decommissioning accruals and gains from decommissioning investments. Components of regulatory liabilities: (Millions of Dollars) See Note(s) Remaining Amortization Period Dec. 31, 2023 Dec. 31, 2022 Regulatory Liabilities Current Noncurrent Current Noncurrent Plant removal costs 1, 10 Various $ — $ 251 $ — $ 223 Deferred income tax adjustments and TCJA refunds (a) 7 Various — 140 — 144 DOE Settlement One two 4 6 12 3 Deferred natural gas and electric energy/fuel costs Less than one 28 — 5 — Other Various 10 10 4 13 Total regulatory liabilities $ 42 $ 407 $ 21 $ 383 (a) Includes the revaluation of recoverable/regulated plant accumulated deferred income taxes and revaluation impact of non-plant accumulated deferred income taxes due to the TCJA. |
Debt
Debt | 12 Months Ended | |
Dec. 31, 2023 | ||
Debt Disclosure [Abstract] | ||
Borrowings and Other Financing Instruments | 5. 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 and the money pool. Money Pool — Xcel Energy Inc. and its utility subsidiaries have established a money pool arrangement that allows for short-term investments in and borrowings between the utility subsidiaries. Xcel Energy Inc. may make investments in the utility subsidiaries at market-based interest rates; however, the money pool arrangement does not allow the utility subsidiaries to make investments in Xcel Energy Inc. Money pool borrowings: (Millions of Dollars, Except Interest Rates) Three Months Ended Dec. 31, 2023 Year Ended 2023 2022 2021 Borrowing limit $ 150 $ 150 $ 150 $ 150 Amount outstanding at period end — — — — Average amount outstanding 7 6 25 16 Maximum amount outstanding 43 43 81 78 Weighted average interest rate, computed on a daily basis 5.34 % 4.98 % 1.10 % 0.05 % Weighted average interest rate at period end N/A N/A N/A N/A Commercial Paper — Commercial paper outstanding: (Millions of Dollars, Except Interest Rates) Three Months Ended Dec. 31, 2023 Year Ended Dec. 31 2023 2022 2021 Borrowing limit $ 150 $ 150 $ 150 $ 150 Amount outstanding at period end 60 60 47 83 Average amount outstanding 10 15 18 3 Maximum amount outstanding 74 93 123 83 Weighted average interest rate, computed on a daily basis 5.48 % 4.85 % 1.03 % 0.18 % Weighted average interest rate at end of period 5.50 5.50 4.55 0.21 Letters of Credit — NSP-Wisconsin may use letters of credit, typically with terms of one year, to provide financial guarantees for certain operating obligations. At Dec. 31, 2023 and 2022, there were immaterial letters of credit outstanding. Credit Facility — In order to use commercial paper programs to fulfill short-term funding needs, NSP-Wisconsin must have revolving credit facilities in place at least equal to the amount of their respective commercial paper borrowing limits and cannot issue commercial paper exceeding available capacity under these credit facilities. The lines of credit provide short-term financing in the form of notes payable to banks, letters of credit and back-up support for commercial paper borrowings. Features of the credit facility: Debt-to-Total Capitalization Ratio (a) Amount Facility May Be Increased (millions of dollars) Additional Periods for Which a One-Year Extension May Be Requested (b) 2023 2022 48.2 % 47.4 % N/A 1 (a) The credit facility has a financial covenant requiring that the debt-to-total capitalization ratio be less than or equal to 65%. (b) All extension requests are subject to majority bank group approval. The credit facility has a cross-default provision that NSP-Wisconsin would be in default on borrowings under the facility if NSP-Wisconsin or any of its subsidiaries, whose total assets exceed 15% of NSP-Wisconsin’s consolidated total assets, default on certain indebtedness in an aggregate principal amount exceeding $75 million. If NSP-Wisconsin does not comply with the covenant, an event of default may be declared, and if not remedied, any outstanding amounts due under the facility can be declared due by the lender . As of Dec. 31, 2023, NSP-Wisconsin was in compliance with all financial covenants. NSP-Wisconsin had the following committed credit facility available as of Dec. 31, 2023 (in millions of dollars): Credit Facility (a) Drawn (b) Available $ 150 $ 60 $ 90 (a) This credit facility matures in September 2027. (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 facility outstanding at Dec. 31, 2023 and 2022, respectively . Other Short-Term Borrowings — Clearwater Investments, Inc., a NSP-Wisconsin subsidiary , had an immaterial note payable to Xcel Energy Inc. at Dec. 31, 2023 and 2022, respectively. Long-Term Borrowings and Other Financing Instruments Generally, the property of NSP-Wisconsin is subject to the lien of its first mortgage indenture for the benefit of bondholders. Debt premiums, discounts and expenses are amortized over the life of the related debt. The premiums, discounts and expenses for refinanced debt are deferred and amortized over the life of new issuance. Long-term debt obligations for NSP-Wisconsin as of Dec. 31 (in millions of dollars): Financing Instrument Interest Rate Maturity Date 2023 2022 First mortgage bonds 3.30 % June 15, 2024 $ 100 $ 100 First mortgage bonds 3.30 June 15, 2024 100 100 First mortgage bonds 6.375 Sept. 1, 2038 200 200 First mortgage bonds 3.70 Oct. 1, 2042 100 100 First mortgage bonds 3.75 Dec. 1, 2047 100 100 First mortgage bonds 4.20 Sept. 1, 2048 200 200 First mortgage bonds 3.05 May 1, 2051 100 100 First mortgage bonds 2.82 May 1, 2051 100 100 First mortgage bonds (a) 4.86 Sept. 15, 2052 100 100 First mortgage bonds (b) 5.30 June 15, 2053 125 — Unamortized discount (3) (3) Unamortized debt issuance cost (11) (11) Current maturities (200) — Total long-term debt $ 1,011 $ 1,086 (a) 2022 financing. (b) 2023 financing. Maturities of long-term debt: (Millions of Dollars) 2024 $ 200 2025 — 2026 — 2027 — 2028 — Deferred Financing Costs — Deferred financing costs of approximately $11 million, net of amortization, are presented as a deduction from the carrying amount of long-term debt at both Dec. 31, 2023 and 2022. Dividend Restrictions — NSP-Wisconsin’s dividends are subject to the FERC’s jurisdiction, which prohibits the payment of dividends out of capital accounts. Dividends are solely to be paid from retained earnings. NSP-Wisconsin’s state regulatory commission additionally imposes dividend limitations, which are more restrictive than those imposed by the FERC. Requirements and actuals as of Dec. 31, 2023: Equity to Total Capitalization Ratio Required Range (a) Equity to Total Capitalization Ratio Actual Low High 2023 52.5 % N/A 52.7 % (a) NSP-Wisconsin cannot pay annual dividends in excess of forecasted levels if its average equity-to-total capitalization ratio falls below the commission authorized level. Unrestricted Retained Earnings Total Capitalization Limit on Total Capitalization $ 9 million $ 2,520 million N/A | [1],[2] |
[1] All extension requests are subject to majority bank group approval. The credit facility has a financial covenant requiring that the debt-to-total capitalization ratio be less than or equal to 65%. |
Revenues
Revenues | 12 Months Ended |
Dec. 31, 2023 | |
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 consisted of the following: Year Ended Dec. 31, 2023 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 299 $ 84 $ — $ 383 C&I 494 65 — 559 Other 7 — 1 8 Total retail 800 149 1 950 Interchange 204 — — 204 Other 3 5 — 8 Total revenue from contracts with customers 1,007 154 1 1,162 Alternative revenue and other 12 3 — 15 Total revenues $ 1,019 $ 157 $ 1 $ 1,177 Year Ended Dec. 31, 2022 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 293 $ 103 $ — $ 396 C&I 485 87 — 572 Other 7 — — 7 Total retail 785 190 — 975 Interchange 202 — — 202 Other 4 4 — 8 Total revenue from contracts with customers 991 194 — 1,185 Alternative revenue and other 11 4 1 16 Total revenues $ 1,002 $ 198 $ 1 $ 1,201 Year Ended Dec. 31, 2021 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 272 $ 91 $ — $ 363 C&I 441 85 — 526 Other 8 — 1 9 Total retail 721 176 1 898 Interchange 189 — — 189 Other — 4 — 4 Total revenue from contracts with customers 910 180 1 1,091 Alternative revenue and other 12 2 — 14 Total revenues $ 922 $ 182 $ 1 $ 1,105 |
Fair Value of Financial Assets
Fair Value of Financial Assets and Liabilities | 12 Months Ended |
Dec. 31, 2023 | |
Fair Value Disclosures [Abstract] | |
Fair Value of Financial Assets and Liabilities | Fair Value Measurements Accounting guidance for fair value measurements and disclosures provides a hierarchical framework for disclosing the observability of the inputs utilized in measuring assets and liabilities at fair value. • 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 actively traded instruments with observable actual trading prices. • Level 2 — Pricing inputs are other than actual trading 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. • 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 include those valued with models requiring significant judgment or estimation. Specific valuation methods include: Commodity derivatives — 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 contracts relate to inactive delivery locations or extend to periods beyond those readily observable on active exchanges, the significance of the use of less observable inputs on a valuation is evaluated, and may result in Level 3 classification. Derivative Activities and Fair Value Measurements NSP-Wisconsin enters into derivative instruments, including forward contracts, futures, swaps and options, to manage risk in connection with changes in utility commodity prices. Commodity Derivatives — NSP-Wisconsin enters into derivative instruments to manage variability of future cash flows from changes in commodity prices in its electric and natural gas operations. This could include the purchase or sale of natural gas to generate electric energy and natural gas for resale. As of Dec. 31, 2023, NSP-Wisconsin had no commodity contracts designated as cash flow hedges. 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 on the consolidated balance sheets. Recurring Derivative Fair Value Measurements Changes in the fair value of natural gas commodity derivatives resulted in immaterial net losses and gains for the year ended Dec. 31, 2023, 2022 and 2021, which were recognized as regulatory assets and liabilities. The classification as a regulatory asset or liability is based on a commission approved regulatory recovery mechanism. During the years ended Dec. 31, 2023, 2022 and 2021, immaterial pre-tax losses were recognized during the period in income related to option premium amortization. NSP-Wisconsin had immaterial outstanding derivative assets or liabilities measured at fair value as of Dec. 31, 2023 and 2022. NSP-Wisconsin had no derivative instruments designated as fair value hedges during the years ended Dec. 31, 2023, 2022 and 2021. Fair Value of Long-Term Debt As of Dec. 31, other financial instruments for which the carrying amount did not equal fair value: 2023 2022 (Millions of Dollars) Carrying Amount Fair Value Carrying Amount Fair Value Long-term debt, including current portion $ 1,211 $ 1,117 $ 1,086 $ 980 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 Dec. 31, 2023 and 2022, 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 | 12 Months Ended |
Dec. 31, 2023 | |
Retirement Benefits [Abstract] | |
Benefit Plans and Other Postretirement Benefits | 9. Benefit Plans and Other Postretirement Benefits Pension and Postretirement Health Care Benefits Xcel Energy, which includes NSP-Wisconsin, has several noncontributory, qualified, defined benefit pension plans that cover almost all employees. All newly hired or rehired employees participate under the Cash Balance formula, which is based on pay credits using a percentage of annual eligible pay and annual interest credits. The average annual interest crediting rates for these plans was 4.67, 4.86 and 1.96 percent in 2023, 2022, and 2021, respectively. Some employees may participate under legacy formulas such as the traditional final average pay or pension equity. Xcel Energy’s policy is to fully fund into an external trust the actuarially determined pension costs subject to the limitations of applicable employee benefit and tax laws. In addition to the qualified pension plans, Xcel Energy maintains a SERP and a nonqualified pension plan. The SERP is maintained for certain executives who participated in the plan in 2008, when the SERP was closed to new participants. The nonqualified pension plan provides benefits for compensation that is in excess of the limits applicable to the qualified pension plans, with distributions funded by Xcel Energy’s consolidated operating cash flows. Obligations of the SERP and nonqualified plan as of Dec. 31, 2023 and 2022 were $12 million and $11 million, respectively, of which the amounts attributable to NSP-Wisconsin were immaterial in both years. Xcel Energy recognized net benefit cost for the SERP and nonqualified plans of $2 million and $17 million in 2023 and 2022, respectively, of which amounts attributable to NSP-Wisconsin were immaterial. Xcel Energy’s postretirement health care benefit plan is a continuation of certain welfare benefit programs for current employees. A full time employee’s date of hire or a retiree’s date of retirement determine eligibility for each of the programs. Xcel Energy’s investment-return assumption considers the expected long-term performance for each of the asset classes in its pension and postretirement health care portfolio. Xcel Energy considers the historical returns achieved by its asset portfolios over long time periods, as well as the long-term projected return levels from investment experts. Xcel Energy and NSP-Wisconsin continually review their pension assumptions. Pension cost determination assumes a forecasted mix of investment types over the long-term. • Investment returns in 2023 were above the assumed level of 7.25%. • Investment returns in 2022 were below the assumed level of 6.60%. • Investment returns in 2021 were above the assumed level of 6.60%. • In 2024, NSP-Wisconsin’s expected investment-return assumption is 7.25%. Pension plan and postretirement benefit assets are invested in a portfolio according to Xcel Energy’s return, liquidity and diversification objectives to provide a source of funding for plan obligations and minimize contributions to the plan, within appropriate levels of risk. The principal mechanism for achieving these objectives is the asset allocation given the long-term risk, return, correlation and liquidity characteristics of each particular asset class. There were no significant concentrations of risk in any industry, index, or entity. Market volatility can impact even well-diversified portfolios and significantly affect the return levels achieved by the assets in any year. Xcel Energy’s ongoing investment strategy is based on plan-specific investment recommendations that seek to minimize potential investment and interest rate risk as a plan’s funded status increases over time. The investment recommendations consider many factors and generally result in a greater percentage of long-duration fixed income securities being allocated to specific plans having relatively higher funded status ratios and a greater percentage of growth assets being allocated to plans having relatively lower funded status ratios. Plan Assets For each of the fair value hierarchy levels, NSP-Wisconsin’s pension plan assets measured at fair value: Dec. 31, 2023 (a) Dec. 31, 2022 (a) (Millions of Dollars) Level 1 Level 2 Level 3 Measured at NAV Total Level 1 Level 2 Level 3 Measured at NAV Total Cash equivalents $ 8 $ — $ — $ — $ 8 $ 4 $ — $ — $ — $ 4 Commingled funds 19 — — 45 64 35 — — 34 69 Debt securities — 22 — — 22 — 22 — — 22 Equity securities 1 — — — 1 2 — — — 2 Total $ 28 $ 22 $ — $ 45 $ 95 $ 41 $ 22 $ — $ 34 $ 97 (a) See Note 8 for further information on fair value measurement inputs and methods. NSP-Wisconsin has immaterial postretirement benefit plan assets that were measured at fair value at Dec. 31, 2023 and 2022. Immaterial assets were transferred in or out of Level 3 for 2023. No assets were transferred in or out of Level 3 for 2022. Funded Status — Comparisons of the actuarially computed benefit obligation, changes in plan assets and funded status of the pension and postretirement health care plans for NSP-Wisconsin are as follows: Pension Benefits Postretirement Benefits (Millions of Dollars) 2023 2022 2023 2022 Change in Benefit Obligation: Obligation at Jan. 1 $ 112 $ 141 $ 8 $ 11 Service cost 4 5 — — Interest cost 6 4 1 1 Actuarial (gain) loss 1 (21) — (3) Benefit payments (11) (17) (1) (1) Obligation at Dec. 31 $ 112 $ 112 $ 8 $ 8 Change in Fair Value of Plan Assets: Fair value of plan assets at Jan. 1 $ 97 $ 137 $ — $ — Actual return on plan assets 5 (24) — — Employer contributions 4 1 1 1 Benefit payments (11) (17) (1) (1) Fair value of plan assets at Dec. 31 $ 95 $ 97 $ — $ — Funded status of plans at Dec. 31 $ (17) $ (15) $ (8) $ (8) Amounts recognized in the Consolidated Balance Sheet at Dec. 31: Current liabilities $ — $ — $ (1) $ — Noncurrent liabilities (17) (15) (7) (8) Net amounts recognized $ (17) $ (15) $ (8) $ (8) Pension Benefits Postretirement Benefits Significant Assumptions Used to Measure Benefit Obligations: 2023 2022 2023 2022 Discount rate for year-end valuation 5.49 % 5.80 % 5.54 % 5.80 % Expected average long-term increase in compensation level 4.25 % 4.25 % N/A N/A Mortality table Pri-2012 Pri-2012 Pri-2012 Pri-2012 Health care costs trend rate — initial: Pre-65 N/A N/A 6.50 % 6.50 % Health care costs trend rate — initial: Post-65 N/A N/A 5.50 % 5.50 % Ultimate trend assumption — initial: Pre-65 N/A N/A 4.50 % 4.50 % Ultimate trend assumption — initial: Post-65 N/A N/A 4.50 % 4.50 % Years until ultimate trend is reached N/A N/A 6 7 Accumulated benefit obligation for the pension plan was $100 million and $101 million as of Dec. 31, 2023 and 2022, respectively. Net Periodic Benefit Cost (Credit) — Net periodic benefit cost (credit), other than the service cost component, is included in other expense in the consolidated statements of income. Components of net periodic benefit cost (credit) and amounts recognized in other comprehensive income and regulatory assets and liabilities: Pension Benefits Postretirement Benefits (Millions of Dollars) 2023 2022 2021 2023 2022 2021 Service cost $ 4 $ 5 $ 5 $ — $ — $ — Interest cost 6 4 4 1 1 1 Expected return on plan assets (8) (8) (8) — — — Amortization of net loss 2 3 5 — — — Settlement charge (a) — 6 5 — — — Net periodic pension cost $ 4 $ 10 $ 11 $ 1 $ 1 $ 1 Effects of regulation — (2) (3) — — Net benefit cost recognized for financial reporting $ 4 $ 8 $ 8 $ 1 $ 1 $ 1 Significant Assumptions Used to Measure Costs: Discount rate 5.80 % 3.08 % 2.71 % 5.80 % 3.09 % 2.65 % Expected average long-term increase in compensation level 4.25 3.75 3.75 — — — Expected average long-term rate of return on assets 7.25 6.60 6.60 5.00 4.10 4.10 (a) A settlement charge is required when the amount of all lump-sum distributions during the year is greater than the sum of the service and interest cost components of the annual net periodic pension cost. There were no settlement charges recorded to the qualified pension plans in 2023. In 2022, as a result of lump-sum distributions during the plan years, NSP-Wisconsin recorded a total pension settlement charge of $5 million, of which $1 million was recorded in the income statement. Pension Benefits Postretirement Benefits (Millions of Dollars) 2023 2022 2023 2022 Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost: Net loss $ 48 $ 45 $ 3 $ 4 Prior service credit — — — — Total $ 48 $ 45 $ 3 $ 4 Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost Have Been Recorded as Follows Based Upon Expected Recovery in Rates: Current regulatory assets $ 2 $ 1 $ — Noncurrent regulatory assets 46 44 3 4 Total $ 48 $ 45 $ 3 $ 4 Measurement date Dec. 31, 2023 Dec. 31, 2022 Dec. 31, 2023 Dec. 31, 2022 Cash Flows — Funding requirements can be impacted by changes to actuarial assumptions, actual asset levels and other calculations prescribed by the requirements of income tax and other pension-related regulations. Required contributions were made in 2020-2023 to meet minimum funding requirements. Total voluntary and required pension funding contributions across all four of Xcel Energy’s pension plans were as follows: • $100 million in January 2024, of which $7 million was attributable to NSP-Wisconsin. • $50 million in 2023, of which $4 million was attributable to NSP-Wisconsin. • $50 million in 2022, of which $1 million was attributable to NSP-Wisconsin. • $131 million in 2021, of which $5 million was attributable to NSP-Wisconsin. The postretirement health care plans have no funding requirements other than fulfilling benefit payment obligations when claims are presented and approved. Additional cash funding requirements are prescribed by certain state and federal rate regulatory authorities. Xcel Energy’s voluntary postretirement funding contributions were as follows: • $11 million expected in 2024, of which $1 million is attributable to NSP-Wisconsin. • $11 million during 2023, of which an immaterial amount was attributable to NSP-Wisconsin. • $13 million during 2022, of which $1 million was attributable to NSP-Wisconsin. • $15 million during 2021, of which $2 million was attributable to NSP-Wisconsin. Target asset allocations: Pension Benefits Postretirement Benefits 2023 2022 2023 2022 Long-duration fixed income and interest rate swap securities 38 % 38 % — % — % Domestic and international equity securities 31 33 9 16 Alternative investments 20 18 13 12 Short-to-intermediate fixed income securities 9 9 77 71 Cash 2 2 1 1 Total 100 % 100 % 100 % 100 % The asset allocations above reflect target allocations approved in the calendar year to take effect in the subsequent year. Plan Amendments — In 2023, Xcel Energy amended the Xcel Energy Pension Plan and Xcel Energy Inc. Nonbargaining Pension Plan (South) to reduce supplemental social security benefits for all active participants on and after Jan. 1, 2024. In 2022, there were no significant plan amendments made which affected the postretirement benefit obligation. In 2021, Xcel Energy amended the Xcel Energy Pension Plan and Xcel Energy Inc. Nonbargaining Pension Plan (South) to reduce supplemental benefits for non-bargaining participants as well as to allow the transfer of a portion of non-qualified pension obligations into the qualified plans. Projected Benefit Payments NSP-Wisconsin’s projected benefit payments: (Millions of Dollars) Projected Net Projected Postretirement Health Care Benefit Payments (a) 2024 $ 17 $ 1 2025 8 1 2026 8 1 2027 9 1 2028 10 1 2029-2033 51 3 (a) Amount is reported net of expected Medicare Part D subsidies, which are immaterial. Voluntary Retirement Program Incremental to amounts presented above for postretirement benefits, Xcel Energy, which includes NSP-Wisconsin, recognized new post employment costs and obligations in the fourth quarter of 2023 for employees accepted to a voluntary retirement program. Utilizing employee information and the following inputs, the estimated NSP-Wisconsin obligations for the program of $2 million for health plan subsidies and an immaterial amount for other medical benefits, each commencing in 2024, were recognized in the fourth quarter of 2023. These unfunded obligations are presented in other current liabilities and noncurrent pension and employee benefit obligations in the consolidated balance sheet as of Dec. 31, 2023. Significant Assumptions to Measure Benefit Obligations: 2023 Discount rate for year-end valuation 5.50 % Mortality table PRI-2012 Health care costs trend rate and ultimate trend assumption 7.00 % Defined Contribution Plans Xcel Energy, which includes NSP-Wisconsin, maintains 401(k) and other defined contribution plans that cover most employees. The expense to these plans for NSP-Wisconsin was approximately $2 million in 2023, 2022 and 2021. Multiemployer Plans NSP-Wisconsin contributes to several union multiemployer pension plans, none of which are individually significant. These plans provide pension benefits to certain union employees who may perform services for multiple employers and do not participate in the NSP-Wisconsin sponsored pension plans. Contributing to these types of plans creates risk that differs from providing benefits under NSP-Wisconsin sponsored plans, in that if another participating employer ceases to contribute to a multiemployer pension plan, additional unfunded obligations may need to be funded over time by remaining participating employers. |
Commitments and Contingencies
Commitments and Contingencies | 12 Months Ended |
Dec. 31, 2023 | |
Commitments and Contingencies Disclosure [Abstract] | |
Commitments and Contingencies | 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, 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 consolidated financial statements. Legal fees are generally 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 involving multiple plaintiffs 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. One case remains active which includes a multi-district litigation matter consisting of a Wisconsin purported class (Arandell Corp.). The Court issued a ruling in June 2022 granting plaintiffs’ class certification. In April 2023, the Seventh Circuit Court of Appeals heard the defendants’ appeal challenging whether the district court properly assessed class certification. A decision relating to class certification is expected imminently. Xcel Energy considers the reasonably possible loss associated with this litigation to be immaterial Rate Matters NSP-Wisconsin is involved in various regulatory proceedings arising in the ordinary course of business. Until resolution, typically in the form of a rate order, uncertainties may exist regarding the ultimate rate treatment for certain activities and transactions. Amounts have been recognized for probable and reasonably estimable losses that may result. Unless otherwise disclosed, any reasonably possible range of loss in excess of any recognized amount is not expected to have a material effect on the consolidated financial statements. MISO ROE Complaints Environmental New and changing federal and state environmental mandates can create financial liabilities for NSP-Wisconsin, which are normally recovered through the regulated rate process. Site Remediation Various federal and state environmental laws impose liability where hazardous substances or other regulated materials have been released to the environment. NSP-Wisconsin may sometimes pay all or a portion of the cost to remediate sites where past activities of NSP-Wisconsin’s predecessors or other parties have caused environmental contamination. Environmental contingencies could arise from various situations, including sites of former MGPs; and third-party sites, such as landfills, for which NSP-Wisconsin is alleged to have sent wastes to that site. AROs — AROs have been recorded for NSP-Wisconsin’s assets. NSP-Wisconsin’s AROs were as follows: 2023 (Millions of Dollars) Jan. 1, 2023 Accretion Cash Flow Revisions (a) Dec. 31, 2023 Electric Steam, hydro and other production $ 10 $ — $ (1) $ 9 Distribution 5 — — 5 Natural gas Distribution 13 1 (6) 8 Total liability (b) $ 28 $ 1 $ (7) $ 22 (a) In 2023, AROs were revised for changes in timing and estimates of cash flows. Changes in gas distribution AROs were a result of updated mileage of gas lines and number of services, as well as changes to inflation and discount rate assumptions. (b) Included in other long-term liabilities balance in the consolidated balance sheet. 2022 (Millions of Dollars) Jan. 1, 2022 Accretion Cash Flow Revisions (a) Dec. 31, 2022 Electric Steam, hydro and other production $ 9 $ 1 $ — $ 10 Distribution 5 — — 5 Natural gas Distribution 12 — 1 13 Total liability (b) $ 26 $ 1 $ 1 $ 28 (a) In 2022, AROs were revised for changes in timing and estimates of cash flows. (b) Included in other long-term liabilities balance in the consolidated balance sheet. Indeterminate AROs — Outside of the recorded asbestos AROs, other plants or buildings may contain asbestos due to the age of many of NSP-Wisconsin’s facilities, but no confirmation or measurement of the cost of removal could be determined as of Dec. 31, 2023. Therefore, an ARO has not been recorded for these facilities. Joint Operating System The electric production and transmission system of NSP-Wisconsin is managed as the NSP System. The electric production and transmission costs of the entire NSP System are shared by NSP-Minnesota and NSP-Wisconsin. A FERC approved agreement between the two companies, called the Interchange Agreement, provides for the sharing of all costs of generation and transmission facilities of the system, including capital costs. Such costs include current and potential obligations of NSP-Minnesota related to its nuclear generating facilities. NSP-Minnesota’s public liability for claims from any nuclear incident is limited to $16.2 billion under the Price-Anderson amendment to the Atomic Energy Act. NSP-Minnesota has secured $450 million of coverage for its public liability exposure with a pool of insurance companies. The remaining $15.8 billion of exposure is funded by the Secondary Financial Protection Program available from assessments by the federal government. NSP-Minnesota is subject to assessments of up to $166 million per reactor-incident for each of its three reactors, for public liability arising from a nuclear incident at any licensed nuclear facility in the United States. The maximum funding requirement is $24.7 million per reactor-incident during any one year. Maximum assessments are subject to inflation adjustments by the NRC. NSP-Minnesota purchases insurance for property damage and site decontamination cleanup costs from NEIL and EMANI. The coverage limits are $2.8 billion for each of NSP-Minnesota’s two nuclear plant sites. NEIL also provides business interruption insurance coverage up to $490 million and $420 million at Monticello and Prairie Island, respectively, including the cost of replacement power during prolonged accidental outages of nuclear generating units. Premiums are expensed over the policy term. All companies insured with NEIL are subject to retroactive premium adjustments if losses exceed accumulated reserve funds. Capital has been accumulated in the reserve funds of NEIL and EMANI to the extent that NSP-Minnesota would have no exposure for retroactive premium assessments in case of a single incident under the business interruption and the property damage insurance coverage. NSP-Minnesota could be subject to annual maximum assessments of $15 million for business interruption insurance and $32 million for property damage insurance if losses exceed accumulated reserve funds. NSP-Wisconsin has entered into various long-term commitments for the purchase and delivery of a significant portion of its refuse-derived fuel/wood and natural gas requirements. These contracts expire between 2024 and 2033. NSP-Wisconsin is required to pay additional amounts depending on actual quantities shipped under these agreements. As NSP-Wisconsin does not have an automatic electric fuel adjustment clause for Wisconsin retail customers, NSP-Wisconsin utilizes deferred accounting treatment for future rate recovery or refund when fuel costs differ from the amount included in rates by more than 2% on an annual basis, as determined by the PSCW after an opportunity for a hearing and an earnings test based on NSP-Wisconsin’s authorized ROE. Estimated minimum purchases under these contracts as of Dec. 31, 2023: (Millions of Dollars) RDF/wood Natural gas Natural gas 2024 $ 6 $ 9 $ 21 2025 1 — 19 2026 1 — 19 2027 — — 13 2028 1 — 3 Thereafter 1 — 8 Total (a) $ 10 $ 9 $ 83 (a) Excludes additional amounts allocated to NSP-Minnesota through intercompany charges. Additional expenditures for fuel and natural gas storage and transportation will be required to meet expected future electric generation and natural gas needs. |
Segments and Related Informatio
Segments and Related Information | 12 Months Ended |
Dec. 31, 2023 | |
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, purchases, transmits, distributes and sells electricity in Michigan and Wisconsin. • Regulated Natural Gas — The regulated natural gas utility segment purchases, transports, stores, distributes and sells natural gas in portions of Michigan and Wisconsin. NSP-Wisconsin also presents All 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 that would be 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: (Millions of Dollars) 2023 2022 2021 Regulated Electric Total revenues (a) $ 1,019 $ 1,002 $ 922 Depreciation and amortization 142 131 120 Interest charges and financing costs 45 38 36 Income tax expense 38 29 27 Net income 126 105 98 Regulated Natural Gas Operating revenues — external $ 157 $ 198 $ 182 Intersegment revenue 1 — 1 Total revenues $ 158 $ 198 $ 183 Depreciation and amortization 28 27 27 Interest charges and financing costs 5 4 4 Income tax expense 2 6 2 Net income 9 17 7 All Other Total revenues $ 1 $ 1 $ 1 Income tax expense — — 1 Net income 1 3 3 Consolidated Total Total revenues (a) $ 1,178 $ 1,201 $ 1,106 Reconciling eliminations (1) — (1) Total operating revenues $ 1,177 $ 1,201 $ 1,105 Depreciation and amortization 170 158 147 Interest charges and financing costs 50 42 40 Income tax expense 40 35 30 Net income 136 125 108 (a) Operating revenues include $204 million, $202 million and $189 million of affiliate electric revenue for the years ended Dec. 31, 2023, 2022 and 2021, respectively. See Note 12 for further information. |
Related Party Transactions
Related Party Transactions | 12 Months Ended |
Dec. 31, 2023 | |
Related Party Transactions [Abstract] | |
Related Party Transactions | 12. Related Party Transactions Xcel Energy Services Inc. provides management, administrative and other services for the subsidiaries of Xcel Energy Inc., including NSP-Wisconsin. The services are provided and billed to each subsidiary in accordance with service agreements executed by each subsidiary. NSP-Wisconsin uses services provided by Xcel Energy Services Inc. whenever possible. Costs are charged directly to the subsidiary and are allocated if they cannot be directly assigned. Xcel Energy, Inc., NSP-Minnesota, NSP-Wisconsin, PSCo and SPS have established a utility money pool arrangement. The electric production and transmission costs of the entire NSP System are shared by NSP-Minnesota and NSP-Wisconsin. The Interchange Agreement provides for the sharing of all costs of generation and transmission facilities of the system, including capital costs. Significant affiliate transactions among the companies and related parties including billings under the Interchange Agreement for the years ended Dec. 31: (Millions of Dollars) 2023 2022 2021 Operating revenues: Electric $ 204 $ 202 $ 189 Operating expenses: Purchased power (a) 424 445 408 Transmission expense 69 68 64 Natural gas purchased for resale 1 — 1 Other operating expenses — paid to Xcel Energy Services Inc. 119 114 99 Interest income 1 — — Interest expense 1 1 — (a) Amount includes $16 million deferred fuel cost regulatory asset for the year ended Dec. 31 2023, and an immaterial amount of fuel costs amortized or deferred for the years ended Dec. 31, 2022 and 2021. Accounts receivable and payable with affiliates at Dec. 31 were: 2023 2022 (Millions of Dollars) Accounts Receivable Accounts Payable Accounts Receivable Accounts Payable NSP-Minnesota $ — $ 9 $ — $ 4 PSCo 1 — 2 — Other subsidiaries of Xcel Energy Inc. 12 13 6 15 $ 13 $ 22 $ 8 $ 19 |
Compensation Related Costs, Pos
Compensation Related Costs, Postemployment Benefits | 12 Months Ended |
Dec. 31, 2023 | |
Postemployment Benefits [Abstract] | |
Postemployment Benefits Disclosure | In 2023, Xcel Energy implemented workforce actions to align resources and investments with evolving business and customer needs, and streamline the organization for long-term success. In September 2023, Xcel Energy announced a voluntary retirement program to a group of eligible non-bargaining employees, with an enhanced retirement package including certain health care and cash benefits for accepted employees. Approximately 400 employees retired under this program in December 2023. In November 2023, Xcel Energy, Inc. also reduced its non-bargaining workforce by approximately 150 employees through an involuntary severance program. In the fourth quarter of 2023, Xcel Energy recorded total expense of $72 million related to these workforce actions, of which $5 million was attributable to NSP-Wisconsin. Expenses relate to the estimated cost of future health plan subsidies and other medical benefits for the voluntary retirement program, as well as severance and other employee payouts and legal and other professional fees. |
Schedule II, Valuation and Qual
Schedule II, Valuation and Qualifying Accounts | 12 Months Ended |
Dec. 31, 2023 | |
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract] | |
Schedule II, Valuation and Qualifying Accounts | NSP-Wisconsin and Subsidiaries Valuation and Qualifying Accounts Years Ended Dec. 31 Allowance for bad debts (Millions of Dollars) 2023 2022 2021 Balance at Jan. 1 $ 9 $ 8 $ 8 Additions charged to costs and expenses 4 4 4 Additions charged to other accounts (a) 1 1 1 Deductions from reserves (b) (5) (4) (5) Balance at Dec. 31 $ 9 $ 9 $ 8 (a) Recovery of amounts previously written-off. (b) Deductions related primarily to bad debt write-offs. |
Summary of Significant Accoun_2
Summary of Significant Accounting Policies (Policies) | 12 Months Ended |
Dec. 31, 2023 | |
Accounting Policies [Abstract] | |
Business and System of Accounts | General — NSP-Wisconsin is engaged in the regulated generation, transmission, distribution and sale of electricity and the regulated purchase, transportation, distribution and sale of natural gas. NSP-Wisconsin’s consolidated financial statements are presented in accordance with GAAP. All of NSP-Wisconsin’s underlying accounting records also conform to the FERC uniform system of accounts or to systems required by various state regulatory commissions. Certain amounts in the consolidated financial statements or notes have been reclassified for comparative purposes; however, such reclassifications did not affect net income, total assets, liabilities, equity or cash flows. |
Principles of Consolidation | NSP-Wisconsin’s consolidated financial statements include its wholly-owned subsidiaries and VIEs for which it is the primary beneficiary. In the consolidation process, all intercompany transactions and balances are eliminated. NSP-Wisconsin has investments in certain transmission facilities jointly owned with nonaffiliated utilities. NSP-Wisconsin’s proportionate share of jointly owned facilities is recorded as property, plant and equipment on the consolidated balance sheets and NSP-Wisconsin’s proportionate share of operating costs associated with these facilities is included in its consolidated statements of income. |
Subsequent Events | NSP-Wisconsin has evaluated events occurring after Dec. 31, 2023 up to the date of issuance of these consolidated financial statements. These statements contain all necessary adjustments and disclosures resulting from that evaluation. |
Use of Estimates | Use of Estimates — NSP-Wisconsin uses estimates based on the best information available to record transactions and balances resulting from business operations. Estimates are used for items such as plant depreciable lives or potential disallowances, AROs, certain regulatory assets and liabilities, tax provisions, uncollectible amounts, environmental costs, unbilled revenues, jurisdictional fuel and energy cost allocations and actuarially determined benefit costs. Recorded estimates are revised when better information becomes available or actual amounts can be determined. Revisions can affect operating results. |
Regulatory Accounting | Regulatory Accounting — NSP-Wisconsin accounts for income and expense items in accordance with accounting guidance for regulated operations. Under this guidance: • Certain costs, which would otherwise be charged to expense or other comprehensive income, are deferred as regulatory assets based on the expected ability to recover the costs in future rates. • Certain credits, which would otherwise be reflected as income or other comprehensive income, are deferred as regulatory liabilities based on the expectation the amounts will be returned to customers in future rates or because the amounts were collected in rates prior to the costs being incurred. Estimates and assumptions for recovery of deferred costs and refund of deferred credits are based on specific ratemaking decisions, precedent or other available information. Regulatory assets and liabilities are amortized consistent with the treatment in the rate setting process. If changes in the regulatory environment occur, NSP-Wisconsin may no longer be eligible to apply this accounting treatment and may be required to eliminate regulatory assets and liabilities. Such changes could have a material effect on NSP-Wisconsin’s results of operations, financial condition and cash flows. See Note 4 for further information. |
Income Taxes | Income Taxes — NSP-Wisconsin accounts for income taxes using the asset and liability method, which requires recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements. Income taxes are deferred for all temporary differences between pretax financial and taxable income and between the book and tax bases of assets and liabilities utilizing rates that are scheduled to be in effect when the temporary differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in the period that includes the enactment date. Utility rate regulation has resulted in the recognition of regulatory assets and liabilities related to income taxes. The effects of NSP-Wisconsin’s tax rate changes are generally subject to a normalization method of accounting. Therefore, the revaluation of most of its net deferred taxes upon a tax rate reduction results in the establishment of a net regulatory liability, refundable to utility customers over the remaining life of the related assets. NSP-Wisconsin anticipates that a tax rate increase would predominantly result in the establishment of a regulatory asset, subject to an evaluation of whether future recovery is expected. Reversal of certain temporary differences are accounted for as current income tax expense due to the effects of past regulatory practices when deferred taxes were not required to be recorded due to the use of flow through accounting for ratemaking purposes. Tax credits are recorded when earned unless there is a requirement to defer the benefit and amortize over the book depreciable lives of related property. The requirement to defer and amortize these credits specifically applies to certain federal ITCs, as determined by tax regulations and NSP-Wisconsin tax elections. For tax credits otherwise eligible to be recognized when earned, NSP-Wisconsin considers the impact of rate regulation to determine if these credits and related adjustments should be deferred as regulatory assets or liabilities. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that some portion or all of the deferred tax asset will not be realized. NSP-Wisconsin measures and discloses uncertain tax positions that it has taken or expects to take in its income tax returns. A tax position is recognized in the consolidated financial statements when it is more likely than not that the position will be sustained upon examination based on the technical merits of the position. Recognition of changes in uncertain tax positions are reflected as a component of income tax expense. Interest and penalties related to income taxes are reported within Other income (expense), net or interest charges in the consolidated statements of income. Xcel Energy Inc. and its subsidiaries, including NSP-Wisconsin file consolidated federal income tax returns as well as consolidated or separate state income tax returns. Federal income taxes paid by Xcel Energy Inc. are allocated to its subsidiaries based on separate company computations. A similar allocation is made for state income taxes paid by Xcel Energy Inc. in connection with consolidated state filings. Xcel Energy Inc. also allocates its own income tax benefits to its direct subsidiaries. See Note 7 for further information. |
Property, Plant and Equipment and Depreciation | Property, Plant and Equipment and Depreciation in Regulated Operations — Property, plant and equipment is stated at original cost. The cost of plant includes direct labor and materials, contracted work, overhead costs and AFUDC. The cost of plant retired is charged to accumulated depreciation and amortization. Amounts recovered in rates for future removal costs are recorded as regulatory liabilities. Significant additions or improvements extending asset lives are capitalized, while repairs and maintenance costs and replacement of items determined to be less than a unit of property are charged to expense as incurred. Property, plant and equipment is tested for impairment when it is determined that the carrying value of the assets may not be recoverable. A loss is recognized in the current period if it becomes probable that part of a cost of a plant under construction or recently completed plant will be disallowed for recovery from customers and a reasonable estimate of the disallowance can be made. For investments in property, plant and equipment that are abandoned and not expected to go into service, incurred costs and related deferred tax amounts are compared to the discounted estimated future rate recovery, and a loss is recognized, if necessary. Depreciation expense is recorded using the straight-line method over the plant’s commission approved useful life. Actuarial life studies are performed and submitted to the state and federal commissions for review. Upon acceptance by the various commissions, the resulting lives and net salvage rates are used to calculate depreciation. Plant removal costs are typically recognized at the amounts recovered in rates as authorized by the applicable regulator. Accumulated removal costs are reflected in the consolidated balance sheet as a regulatory liability. Depreciation expense, expressed as a percentage of average depreciable property, was approximately 3.6% in 2023, 2022 and 2021. |
Asset Retirement Obligations | AROs — NSP-Wisconsin records AROs as a liability in the period incurred (if fair value can be reasonably estimated), with the offsetting/associated costs capitalized as a long-lived asset. The liability is generally increased over time by applying the effective interest method of accretion and the capitalized costs are typically depreciated over the useful life of the long-lived asset. Changes resulting from revisions to timing or amounts of expected asset retirement cash flows are recognized as an increase or a decrease in the ARO. See Note 10 for further information. |
Benefit Plans and Other Postretirement Benefits | Benefit Plans and Other Postretirement Benefits — NSP-Wisconsin maintains pension and postretirement benefit plans for eligible employees. Recognizing the cost of providing benefits and measuring the projected benefit obligation of these plans requires management to make various assumptions and estimates. Certain unrecognized actuarial gains and losses and unrecognized prior service costs or credits are deferred as regulatory assets and liabilities, rather than recorded as other comprehensive income, based on regulatory recovery mechanisms. See Note 9 for further information. |
Environmental Costs | Environmental Costs — Environmental costs are recorded when it is probable NSP-Wisconsin is liable for remediation costs and the amount can be reasonably estimated. Costs are deferred as a regulatory asset if it is probable the costs will be recovered from customers in future rates. Otherwise, the costs are expensed. For certain environmental costs related to facilities currently in use, such as for emission-control equipment, the cost is capitalized and depreciated over the life of the plant. Estimated remediation costs are regularly adjusted as estimates are revised and remediation is performed. If other participating potentially responsible parties exist and acknowledge their potential involvement with a site, costs are estimated and recorded only for NSP-Wisconsin’s expected share of the cost. Estimated future expenditures to restore sites are treated as a capitalized cost of plant retirement. The depreciation expense levels recoverable in rates include a provision for removal expenses. Removal costs recovered in rates before the related costs are incurred are classified as a regulatory liability. See Note 10 for further information. |
Revenue From Contracts With Customers | Revenue from Contracts with Customers — Performance obligations related to the sale of energy are satisfied as energy is delivered to customers. NSP-Wisconsin recognizes revenue that corresponds to the price of the energy delivered to the customer. The measurement of energy sales to customers is generally based on the reading of their meters, which occurs systematically throughout the month. At the end of each month, amounts of energy delivered to customers since the date of the last meter reading are estimated, and the corresponding unbilled revenue is recognized. A separate financing component of collections from customers is not recognized as contract terms are short-term in nature. Revenues are net of any excise or sales taxes or fees. NSP-Wisconsin has various rate-adjustment mechanisms that provide for the recovery of natural gas, electric fuel and purchased energy costs. Cost-adjustment tariffs may increase or decrease the level of revenue collected from customers and are revised periodically for differences between the total amount collected under the clauses and the costs incurred. When applicable, fuel cost over-recoveries (the excess of fuel revenue billed to customers over fuel costs incurred) are deferred as regulatory liabilities and under-recoveries (the excess of fuel costs incurred over fuel revenues billed to customers) are deferred as regulatory assets. NSP-Wisconsin must submit a forward looking fuel cost plan annually for approval by the PSCW. The rules also allow for deferral of any under-recovery or over-recovery of fuel costs in excess of a 2% annual tolerance band, for future rate recovery or refund, subject to PSCW approval. |
Cash and Cash Equivalents | Cash and Cash Equivalents — NSP-Wisconsin considers investments in instruments with a remaining maturity of three months or less at the time of purchase to be cash equivalents. |
Accounts Receivable and Allowance for Bad Debts | Accounts Receivable and Allowance for Bad Debts — Accounts receivable are stated at the actual billed amount net of an allowance for bad debts. NSP-Wisconsin establishes an allowance for uncollectible receivables based on a policy that reflects its expected exposure to the credit risk of customers. |
Inventory | Inventory — Inventory is recorded at the lower of average cost or net realizable value and consisted of the following: (Millions of Dollars) Dec. 31, 2023 Dec. 31, 2022 Inventories Materials and supplies $ 11 $ 8 Fuel 10 11 Natural gas 8 20 Total inventories $ 29 $ 39 |
Fair Value Measurements | Fair Value Measurements — NSP-Wisconsin presents cash equivalents, interest rate derivatives, rabbi trust assets, commodity derivatives, pension and postretirement plan assets at estimated fair values in its consolidated financial statements. For interest rate derivatives, quoted prices based primarily on observable market interest rate curves are used to estimate fair value. For commodity derivatives, the most observable inputs available are generally used to determine the fair value of each contract. In the absence of a quoted price, quoted prices for similar contracts or internally prepared valuation models may be used to determine fair value. For the pension and postretirement plan assets, published trading data and pricing models, generally using the most observable inputs available, are utilized to determine fair value for each security. See Notes 8 and 9 for further information. |
Derivative Instruments | Derivative Instruments — NSP-Wisconsin uses derivative instruments in connection with its commodity trading activities, and to manage risk associated with changes in interest rates and utility commodity prices, including forward contracts, futures, swaps and options. Derivatives not qualifying for the normal purchases and normal sales exception are recorded on the consolidated balance sheets at fair value as derivative instruments. Classification of changes in fair value for those derivative instruments is dependent on the designation of a qualifying hedging relationship. Changes in fair value of derivative instruments not designated in a qualifying hedging relationship are reflected in current earnings or as a regulatory asset or liability. Classification as a regulatory asset or liability is based on commission approved regulatory recovery mechanisms. Gains or losses on commodity trading transactions are recorded as a component of electric operating revenues. Normal Purchases and Normal Sales — NSP-Wisconsin enters into contracts for purchases and sales of commodities for use in its operations. At inception, contracts are evaluated to determine whether they contain a derivative, and if so, whether they may be exempted from derivative accounting if designated as normal purchases or normal sales. See Note 8 for further information. |
AFUDC | AFUDC |
Alternative revenue programs | Alternative Revenue — Certain rate rider mechanisms qualify as alternative revenue programs. These mechanisms arise from instances in which the regulator authorizes a future surcharge in response to past activities or completed events. When certain criteria are met, including expected collection within 24 months, revenue is recognized, which may include incentives and return on rate base items. The mechanisms are revised periodically for differences between total amount collected and the revenue earned, which may increase or decrease the level of revenue collected from customers. Alternative revenues arising from these programs are presented on a gross basis and disclosed separately from revenue from contracts with customers. See Note 6 for further information. Conservation Programs — NSP-Wisconsin participates in and funds conservation programs in its retail jurisdictions to assist customers in conserving energy and reducing peak demand on the electric and natural gas systems. NSP-Wisconsin recovers approved conservation program costs in base rate revenue. three |
Emission Allowances | Emissions Allowances — Emissions allowances are recorded at cost, including broker commission fees. The inventory accounting model is utilized for all emissions allowances and any sales of these allowances are included in electric revenues. |
Renewable Energy Credits | RECs — |
Summary of Significant Accoun_3
Summary of Significant Accounting Policies Inventory (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Balance Sheet Related Disclosure - Inventory [Abstract] | |
Public Utilities, Inventory | Inventory — Inventory is recorded at the lower of average cost or net realizable value and consisted of the following: (Millions of Dollars) Dec. 31, 2023 Dec. 31, 2022 Inventories Materials and supplies $ 11 $ 8 Fuel 10 11 Natural gas 8 20 Total inventories $ 29 $ 39 |
Property Plant and Equipment _2
Property Plant and Equipment Property Plant and Equipment (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Property, Plant and Equipment [Abstract] | |
Public Utility Property, Plant, and Equipment | Major classes of property, plant and equipment (Millions of Dollars) Dec. 31, 2023 Dec. 31, 2022 Property, plant and equipment, net Electric plant $ 3,845 $ 3,579 Natural gas plant 502 465 Common and other property 278 260 CWIP 252 174 Total property, plant and equipment 4,877 4,478 Less accumulated depreciation (1,640) (1,564) Property, plant and equipment, net $ 3,237 $ 2,914 |
Schedule of Jointly Owned Utility Plants | Jointly owned assets as of Dec. 31, 2023: (Millions of Dollars, Except Percent Owned) Plant in Service Accumulated Depreciation Percent Owned Electric transmission: La Crosse, WI to Madison, WI $ 178 $ 25 37 % CapX2020 169 39 80 Total (a) $ 347 $ 64 (a) Projects additionally include $1 million in CWIP. |
Regulatory Assets and Liabili_2
Regulatory Assets and Liabilities (Tables) | 12 Months Ended | |
Dec. 31, 2023 | ||
Regulatory Assets and Liabilities Disclosure [Abstract] | ||
Regulatory Assets | Components of regulatory assets: (Millions of Dollars) See Note(s) Remaining Amortization Period Dec. 31, 2023 Dec. 31, 2022 Regulatory Assets Current Noncurrent Current Noncurrent Pension and retiree medical obligations 9 Various 2 62 2 61 Environmental remediation costs 1, 10 Various $ 13 $ 48 $ 13 $ 63 Recoverable deferred taxes on AFUDC Plant lives — 26 — 20 State commission adjustments Plant lives 1 22 1 22 Net AROs (a) 1, 10 Various — 21 — 18 Deferred natural gas and electric energy/fuel costs 7 Less than one 1 — 23 — Other Various 7 6 5 9 Total regulatory assets $ 24 $ 185 $ 44 $ 193 (a) Includes amounts recorded for future recovery of AROs, less amounts recovered through NSP-Wisconsin’s share of nuclear decommissioning accruals and gains from decommissioning investments. | |
Regulatory Liabilities | Components of regulatory liabilities: (Millions of Dollars) See Note(s) Remaining Amortization Period Dec. 31, 2023 Dec. 31, 2022 Regulatory Liabilities Current Noncurrent Current Noncurrent Plant removal costs 1, 10 Various $ — $ 251 $ — $ 223 Deferred income tax adjustments and TCJA refunds (a) 7 Various — 140 — 144 DOE Settlement One two 4 6 12 3 Deferred natural gas and electric energy/fuel costs Less than one 28 — 5 — Other Various 10 10 4 13 Total regulatory liabilities $ 42 $ 407 $ 21 $ 383 (a) Includes the revaluation of recoverable/regulated plant accumulated deferred income taxes and revaluation impact of non-plant accumulated deferred income taxes due to the TCJA. | [1] |
[1] Includes the revaluation of recoverable/regulated plant accumulated deferred income taxes and revaluation impact of non-plant accumulated deferred income taxes due to the TCJA. |
Borrowings and Other Financing
Borrowings and Other Financing Instruments Borrowings and Other Financing Instruments (Tables) | 12 Months Ended | |
Dec. 31, 2023 | ||
Debt Disclosure [Abstract] | ||
Money Pool | Money pool borrowings: (Millions of Dollars, Except Interest Rates) Three Months Ended Dec. 31, 2023 Year Ended 2023 2022 2021 Borrowing limit $ 150 $ 150 $ 150 $ 150 Amount outstanding at period end — — — — Average amount outstanding 7 6 25 16 Maximum amount outstanding 43 43 81 78 Weighted average interest rate, computed on a daily basis 5.34 % 4.98 % 1.10 % 0.05 % Weighted average interest rate at period end N/A N/A N/A N/A | |
Commercial Paper | Commercial paper outstanding: (Millions of Dollars, Except Interest Rates) Three Months Ended Dec. 31, 2023 Year Ended Dec. 31 2023 2022 2021 Borrowing limit $ 150 $ 150 $ 150 $ 150 Amount outstanding at period end 60 60 47 83 Average amount outstanding 10 15 18 3 Maximum amount outstanding 74 93 123 83 Weighted average interest rate, computed on a daily basis 5.48 % 4.85 % 1.03 % 0.18 % Weighted average interest rate at end of period 5.50 5.50 4.55 0.21 | |
Schedule of Debt To Total Capitalization Ratio | Debt-to-Total Capitalization Ratio (a) Amount Facility May Be Increased (millions of dollars) Additional Periods for Which a One-Year Extension May Be Requested (b) 2023 2022 48.2 % 47.4 % N/A 1 (a) The credit facility has a financial covenant requiring that the debt-to-total capitalization ratio be less than or equal to 65%. (b) | |
Credit Facilities | NSP-Wisconsin had the following committed credit facility available as of Dec. 31, 2023 (in millions of dollars): Credit Facility (a) Drawn (b) Available $ 150 $ 60 $ 90 (a) This credit facility matures in September 2027. (b) Includes outstanding commercial paper. | [1],[2] |
Schedule of Long-Term Debt | Long-term debt obligations for NSP-Wisconsin as of Dec. 31 (in millions of dollars): Financing Instrument Interest Rate Maturity Date 2023 2022 First mortgage bonds 3.30 % June 15, 2024 $ 100 $ 100 First mortgage bonds 3.30 June 15, 2024 100 100 First mortgage bonds 6.375 Sept. 1, 2038 200 200 First mortgage bonds 3.70 Oct. 1, 2042 100 100 First mortgage bonds 3.75 Dec. 1, 2047 100 100 First mortgage bonds 4.20 Sept. 1, 2048 200 200 First mortgage bonds 3.05 May 1, 2051 100 100 First mortgage bonds 2.82 May 1, 2051 100 100 First mortgage bonds (a) 4.86 Sept. 15, 2052 100 100 First mortgage bonds (b) 5.30 June 15, 2053 125 — Unamortized discount (3) (3) Unamortized debt issuance cost (11) (11) Current maturities (200) — Total long-term debt $ 1,011 $ 1,086 (a) 2022 financing. (b) 2023 financing. | |
Schedule of Maturities of Long-term Debt | Maturities of long-term debt: (Millions of Dollars) 2024 $ 200 2025 — 2026 — 2027 — 2028 — | |
Dividend Payment Restrictions | Equity to Total Capitalization Ratio Required Range (a) Equity to Total Capitalization Ratio Actual Low High 2023 52.5 % N/A 52.7 % (a) NSP-Wisconsin cannot pay annual dividends in excess of forecasted levels if its average equity-to-total capitalization ratio falls below the commission authorized level. Unrestricted Retained Earnings Total Capitalization Limit on Total Capitalization $ 9 million $ 2,520 million N/A | |
[1] This credit facility matures in September 2027. |
Revenues Revenues (Tables)
Revenues Revenues (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Revenue from Contract with Customer [Abstract] | |
Disaggregation of Revenue [Table Text Block] | NSP-Wisconsin’s operating revenues consisted of the following: Year Ended Dec. 31, 2023 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 299 $ 84 $ — $ 383 C&I 494 65 — 559 Other 7 — 1 8 Total retail 800 149 1 950 Interchange 204 — — 204 Other 3 5 — 8 Total revenue from contracts with customers 1,007 154 1 1,162 Alternative revenue and other 12 3 — 15 Total revenues $ 1,019 $ 157 $ 1 $ 1,177 Year Ended Dec. 31, 2022 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 293 $ 103 $ — $ 396 C&I 485 87 — 572 Other 7 — — 7 Total retail 785 190 — 975 Interchange 202 — — 202 Other 4 4 — 8 Total revenue from contracts with customers 991 194 — 1,185 Alternative revenue and other 11 4 1 16 Total revenues $ 1,002 $ 198 $ 1 $ 1,201 Year Ended Dec. 31, 2021 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 272 $ 91 $ — $ 363 C&I 441 85 — 526 Other 8 — 1 9 Total retail 721 176 1 898 Interchange 189 — — 189 Other — 4 — 4 Total revenue from contracts with customers 910 180 1 1,091 Alternative revenue and other 12 2 — 14 Total revenues $ 922 $ 182 $ 1 $ 1,105 |
Income Taxes (Tables)
Income Taxes (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Income Tax Disclosure [Abstract] | |
Schedule of Effective Income Tax Rate Reconciliation | Effective income tax rate for years ended Dec. 31: 2023 2022 2021 Federal statutory rate 21.0 % 21.0 % 21.0 % State income tax on pretax income, net of federal tax effect 6.2 6.2 6.2 Decreases in tax from: Plant regulatory differences (a) (3.4) (3.8) (4.1) Other tax credits, net NOL & tax credit allowances (0.6) (0.8) (1.0) Other, net (0.5) (0.7) (0.4) Effective income tax rate 22.7 % 21.9 % 21.7 % (a) Plant regulatory differences primarily relate to the credit of excess deferred taxes to customers through the average rate assumption method. Income tax benefits associated with the credit are offset by corresponding revenue reductions. |
Schedule of Components of Income Tax Expense (Benefit) | Components of income tax expense for years ended Dec. 31: (Millions of Dollars) 2023 2022 2021 Current federal tax expense $ 37 $ 28 $ 17 Current state tax expense 15 9 4 Deferred federal tax (benefit) expense (10) (5) 3 Deferred state tax (benefit) expense (3) 3 6 Deferred change in unrecognized tax expense 1 — — Total income tax expense $ 40 $ 35 $ 30 Components of deferred income tax expense as of Dec. 31: (Millions of Dollars) 2023 2022 2021 Deferred tax (benefit) expense excluding items below $ (3) $ 8 $ 18 Amortization and adjustments to deferred income taxes on income tax regulatory assets and liabilities (10) (10) (10) Other 1 — 1 Deferred tax (benefit) expense $ (12) $ (2) $ 9 |
Schedule of Deferred Tax Assets and Liabilities | Components of the net deferred tax liability as of Dec. 31: (Millions of Dollars) 2023 2022 (a) Deferred tax liabilities: Difference between book and tax bases of property $ 350 $ 343 Regulatory assets 22 24 Pension expense 10 10 Deferred fuel costs — 6 Other 7 8 Total deferred tax liabilities $ 389 $ 391 Deferred tax assets: Regulatory liabilities $ 32 $ 35 Rate refund 10 3 Environmental remediation 4 4 Other employee benefits 4 3 Tax credit carryforward 3 7 Deferred ITCs 2 2 Other 4 4 Total deferred tax assets $ 59 $ 58 Net deferred tax liability $ 330 $ 333 (a) Prior periods have been reclassified to conform to current year presentation. |
NOL and Tax Credit Carryforwards | NOL amounts represent the tax loss that is carried forward and tax credits represent the deferred tax asset. NOL and tax credit carryforwards as of Dec. 31 were as follows: (Millions of Dollars) 2023 2022 Federal tax credit carryforwards $ 3 $ 7 State NOL carryforward 2 2 |
Summary of Statute of Limitations Applicable to Open Tax Years [Table Text Block] | 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 Year(s) Expiration 2014 - 2016 March 2025 2020 September 2024 |
Reconciliation of Unrecognized Tax Benefits | Unrecognized tax benefits — permanent vs. temporary: (Millions of Dollars) Dec. 31, 2023 Dec. 31, 2022 Unrecognized tax benefit — Permanent tax positions $ 3 $ 2 Unrecognized tax benefit — Temporary tax positions — 1 Total unrecognized tax benefit $ 3 $ 3 Changes in unrecognized tax benefits: (Millions of Dollars) 2023 2022 2021 Balance at Jan. 1 $ 3 $ 3 $ 2 Additions for tax positions of prior years — — 1 Balance at Dec. 31 $ 3 $ 3 $ 3 |
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) Dec. 31, 2023 Dec. 31, 2022 NOL and tax credit carryforwards $ (2) $ (2) |
State Statute of Limitations Applicable to Open Tax Years | NSP-Wisconsin is a member of the Xcel Energy affiliated group that files consolidated state income tax returns. As of Dec. 31, 2023, NSP-Wisconsin’s earliest open tax years that are subject to examination by state taxing authorities under applicable statutes of limitations are as follows: State Tax Year(s) Expiration Wisconsin 2016-2018 May 2024 Wisconsin 2019 October 2024 |
Fair Value of Financial Asset_2
Fair Value of Financial Assets and Liabilities (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Fair Value Disclosures [Abstract] | |
Carrying Amount and Fair Value of Long-term Debt | As of Dec. 31, other financial instruments for which the carrying amount did not equal fair value: 2023 2022 (Millions of Dollars) Carrying Amount Fair Value Carrying Amount Fair Value Long-term debt, including current portion $ 1,211 $ 1,117 $ 1,086 $ 980 |
Benefit Plans and Other Postr_2
Benefit Plans and Other Postretirement Benefits (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Benefit Plans and Other Postretirement Benefits [Abstract] | |
Funded Status of Plans | Pension Benefits Postretirement Benefits (Millions of Dollars) 2023 2022 2023 2022 Change in Benefit Obligation: Obligation at Jan. 1 $ 112 $ 141 $ 8 $ 11 Service cost 4 5 — — Interest cost 6 4 1 1 Actuarial (gain) loss 1 (21) — (3) Benefit payments (11) (17) (1) (1) Obligation at Dec. 31 $ 112 $ 112 $ 8 $ 8 Change in Fair Value of Plan Assets: Fair value of plan assets at Jan. 1 $ 97 $ 137 $ — $ — Actual return on plan assets 5 (24) — — Employer contributions 4 1 1 1 Benefit payments (11) (17) (1) (1) Fair value of plan assets at Dec. 31 $ 95 $ 97 $ — $ — Funded status of plans at Dec. 31 $ (17) $ (15) $ (8) $ (8) Amounts recognized in the Consolidated Balance Sheet at Dec. 31: Current liabilities $ — $ — $ (1) $ — Noncurrent liabilities (17) (15) (7) (8) Net amounts recognized $ (17) $ (15) $ (8) $ (8) Pension Benefits Postretirement Benefits Significant Assumptions Used to Measure Benefit Obligations: 2023 2022 2023 2022 Discount rate for year-end valuation 5.49 % 5.80 % 5.54 % 5.80 % Expected average long-term increase in compensation level 4.25 % 4.25 % N/A N/A Mortality table Pri-2012 Pri-2012 Pri-2012 Pri-2012 Health care costs trend rate — initial: Pre-65 N/A N/A 6.50 % 6.50 % Health care costs trend rate — initial: Post-65 N/A N/A 5.50 % 5.50 % Ultimate trend assumption — initial: Pre-65 N/A N/A 4.50 % 4.50 % Ultimate trend assumption — initial: Post-65 N/A N/A 4.50 % 4.50 % Years until ultimate trend is reached N/A N/A 6 7 |
Components of Net Periodic Benefit Costs | Pension Benefits Postretirement Benefits (Millions of Dollars) 2023 2022 2021 2023 2022 2021 Service cost $ 4 $ 5 $ 5 $ — $ — $ — Interest cost 6 4 4 1 1 1 Expected return on plan assets (8) (8) (8) — — — Amortization of net loss 2 3 5 — — — Settlement charge (a) — 6 5 — — — Net periodic pension cost $ 4 $ 10 $ 11 $ 1 $ 1 $ 1 Effects of regulation — (2) (3) — — Net benefit cost recognized for financial reporting $ 4 $ 8 $ 8 $ 1 $ 1 $ 1 Significant Assumptions Used to Measure Costs: Discount rate 5.80 % 3.08 % 2.71 % 5.80 % 3.09 % 2.65 % Expected average long-term increase in compensation level 4.25 3.75 3.75 — — — Expected average long-term rate of return on assets 7.25 6.60 6.60 5.00 4.10 4.10 (a) A settlement charge is required when the amount of all lump-sum distributions during the year is greater than the sum of the service and interest cost components of the annual net periodic pension cost. There were no settlement charges recorded to the qualified pension plans in 2023. In 2022, as a result of lump-sum distributions during the plan years, NSP-Wisconsin recorded a total pension settlement charge of $5 million, of which $1 million was recorded in the income statement. |
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost | Pension Benefits Postretirement Benefits (Millions of Dollars) 2023 2022 2023 2022 Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost: Net loss $ 48 $ 45 $ 3 $ 4 Prior service credit — — — — Total $ 48 $ 45 $ 3 $ 4 Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost Have Been Recorded as Follows Based Upon Expected Recovery in Rates: Current regulatory assets $ 2 $ 1 $ — Noncurrent regulatory assets 46 44 3 4 Total $ 48 $ 45 $ 3 $ 4 |
Target Asset Allocations and Plan Assets Measured at Fair Value | For each of the fair value hierarchy levels, NSP-Wisconsin’s pension plan assets measured at fair value: Dec. 31, 2023 (a) Dec. 31, 2022 (a) (Millions of Dollars) Level 1 Level 2 Level 3 Measured at NAV Total Level 1 Level 2 Level 3 Measured at NAV Total Cash equivalents $ 8 $ — $ — $ — $ 8 $ 4 $ — $ — $ — $ 4 Commingled funds 19 — — 45 64 35 — — 34 69 Debt securities — 22 — — 22 — 22 — — 22 Equity securities 1 — — — 1 2 — — — 2 Total $ 28 $ 22 $ — $ 45 $ 95 $ 41 $ 22 $ — $ 34 $ 97 (a) See Note 8 for further information on fair value measurement inputs and methods. NSP-Wisconsin has immaterial postretirement benefit plan assets that were measured at fair value at Dec. 31, 2023 and 2022. Immaterial assets were transferred in or out of Level 3 for 2023. No assets were transferred in or out of Level 3 for 2022. Target asset allocations: Pension Benefits Postretirement Benefits 2023 2022 2023 2022 Long-duration fixed income and interest rate swap securities 38 % 38 % — % — % Domestic and international equity securities 31 33 9 16 Alternative investments 20 18 13 12 Short-to-intermediate fixed income securities 9 9 77 71 Cash 2 2 1 1 Total 100 % 100 % 100 % 100 % The asset allocations above reflect target allocations approved in the calendar year to take effect in the subsequent year. |
Projected Benefit Payments for the Pension and Postretirement Benefit Plans | (Millions of Dollars) Projected Net Projected Postretirement Health Care Benefit Payments (a) 2024 $ 17 $ 1 2025 8 1 2026 8 1 2027 9 1 2028 10 1 2029-2033 51 3 (a) Amount is reported net of expected Medicare Part D subsidies, which are immaterial. |
Commitments and Contingencies (
Commitments and Contingencies (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Commitments and Contingencies Disclosure [Abstract] | |
Asset Retirement Obligations | NSP-Wisconsin’s AROs were as follows: 2023 (Millions of Dollars) Jan. 1, 2023 Accretion Cash Flow Revisions (a) Dec. 31, 2023 Electric Steam, hydro and other production $ 10 $ — $ (1) $ 9 Distribution 5 — — 5 Natural gas Distribution 13 1 (6) 8 Total liability (b) $ 28 $ 1 $ (7) $ 22 (a) In 2023, AROs were revised for changes in timing and estimates of cash flows. Changes in gas distribution AROs were a result of updated mileage of gas lines and number of services, as well as changes to inflation and discount rate assumptions. (b) Included in other long-term liabilities balance in the consolidated balance sheet. 2022 (Millions of Dollars) Jan. 1, 2022 Accretion Cash Flow Revisions (a) Dec. 31, 2022 Electric Steam, hydro and other production $ 9 $ 1 $ — $ 10 Distribution 5 — — 5 Natural gas Distribution 12 — 1 13 Total liability (b) $ 26 $ 1 $ 1 $ 28 (a) In 2022, AROs were revised for changes in timing and estimates of cash flows. (b) Included in other long-term liabilities balance in the consolidated balance sheet. |
Estimated Minimum Purchases Under Fuel Contracts | Estimated minimum purchases under these contracts as of Dec. 31, 2023: (Millions of Dollars) RDF/wood Natural gas Natural gas 2024 $ 6 $ 9 $ 21 2025 1 — 19 2026 1 — 19 2027 — — 13 2028 1 — 3 Thereafter 1 — 8 Total (a) $ 10 $ 9 $ 83 (a) Excludes additional amounts allocated to NSP-Minnesota through intercompany charges. |
Estimated Minimum Purchases Under Fuel Contracts | (Millions of Dollars) RDF/wood Natural gas Natural gas 2024 $ 6 $ 9 $ 21 2025 1 — 19 2026 1 — 19 2027 — — 13 2028 1 — 3 Thereafter 1 — 8 Total (a) $ 10 $ 9 $ 83 |
Segments and Related Informat_2
Segments and Related Information (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Segment Reporting [Abstract] | |
Results from Operations by Reportable Segment | NSP-Wisconsin’s segment information: (Millions of Dollars) 2023 2022 2021 Regulated Electric Total revenues (a) $ 1,019 $ 1,002 $ 922 Depreciation and amortization 142 131 120 Interest charges and financing costs 45 38 36 Income tax expense 38 29 27 Net income 126 105 98 Regulated Natural Gas Operating revenues — external $ 157 $ 198 $ 182 Intersegment revenue 1 — 1 Total revenues $ 158 $ 198 $ 183 Depreciation and amortization 28 27 27 Interest charges and financing costs 5 4 4 Income tax expense 2 6 2 Net income 9 17 7 All Other Total revenues $ 1 $ 1 $ 1 Income tax expense — — 1 Net income 1 3 3 Consolidated Total Total revenues (a) $ 1,178 $ 1,201 $ 1,106 Reconciling eliminations (1) — (1) Total operating revenues $ 1,177 $ 1,201 $ 1,105 Depreciation and amortization 170 158 147 Interest charges and financing costs 50 42 40 Income tax expense 40 35 30 Net income 136 125 108 (a) Operating revenues include $204 million, $202 million and $189 million of affiliate electric revenue for the years ended Dec. 31, 2023, 2022 and 2021, respectively. See Note 12 for further information. |
Related Party Transactions (Tab
Related Party Transactions (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Related Party Transactions [Abstract] | |
Related Party Transactions | Significant affiliate transactions among the companies and related parties including billings under the Interchange Agreement for the years ended Dec. 31: (Millions of Dollars) 2023 2022 2021 Operating revenues: Electric $ 204 $ 202 $ 189 Operating expenses: Purchased power (a) 424 445 408 Transmission expense 69 68 64 Natural gas purchased for resale 1 — 1 Other operating expenses — paid to Xcel Energy Services Inc. 119 114 99 Interest income 1 — — Interest expense 1 1 — (a) Amount includes $16 million deferred fuel cost regulatory asset for the year ended Dec. 31 2023, and an immaterial amount of fuel costs amortized or deferred for the years ended Dec. 31, 2022 and 2021. Accounts receivable and payable with affiliates at Dec. 31 were: 2023 2022 (Millions of Dollars) Accounts Receivable Accounts Payable Accounts Receivable Accounts Payable NSP-Minnesota $ — $ 9 $ — $ 4 PSCo 1 — 2 — Other subsidiaries of Xcel Energy Inc. 12 13 6 15 $ 13 $ 22 $ 8 $ 19 |
Summary of Significant Accoun_4
Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | |
Property, Plant and Equipment [Abstract] | |||
Depreciation expense expressed as a percentage of average depreciable property | 3.60% | 3.60% | 3.60% |
Operating revenues | |||
Minimum annual tolerance band percentage for future rate recovery or refund of fuel costs | 2% | ||
Cash and Cash Equivalents [Abstract] | |||
Maximum number of months of remaining maturity at time of purchase to consider investments in certain instruments as cash equivalents | 3 months | ||
Accounts and Financing Receivable, after Allowance for Credit Loss, Current and Noncurrent [Abstract] | |||
Accounts Receivable, Allowance for Credit Loss, Current | $ 9 | $ 9 | |
Alternative Revenue Programs [Abstract] | |||
Maximum number of months following end of annual period in which revenues are earned to be included in incentive programs | 24 months | ||
Percentage of Average Annual Operating Revenues | 1.20% | ||
Number of Years Annual Operating Revenues are Averaged | 3 years | ||
Public Utilities, Inventory [Line Items] | |||
Inventories | $ 29 | 39 | |
Accounts Receivable, Allowance for Credit Loss, Current | $ 9 | $ 9 | |
Depreciation expense expressed as a percentage of average depreciable property | 3.60% | 3.60% | 3.60% |
Materials and supplies | |||
Public Utilities, Inventory [Line Items] | |||
Inventories | $ 11 | $ 8 | |
Fuel | |||
Public Utilities, Inventory [Line Items] | |||
Inventories | 10 | 11 | |
Natural gas | |||
Public Utilities, Inventory [Line Items] | |||
Inventories | $ 8 | $ 20 |
Property Plant and Equipment _3
Property Plant and Equipment Property Plant and Equipment (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022 |
Property, Plant and Equipment [Line Items] | ||
Property, Plant and Equipment | $ 4,877 | $ 4,478 |
Accumulated Depreciation | 1,640 | 1,564 |
Property, Plant and Equipment, Net | 3,237 | 2,914 |
Electric plant | ||
Property, Plant and Equipment [Line Items] | ||
Property, Plant and Equipment | 3,845 | 3,579 |
Natural gas plant | ||
Property, Plant and Equipment [Line Items] | ||
Property, Plant and Equipment | 502 | 465 |
Common and other property | ||
Property, Plant and Equipment [Line Items] | ||
Property, Plant and Equipment | 278 | 260 |
CWIP | ||
Property, Plant and Equipment [Line Items] | ||
Property, Plant and Equipment | $ 252 | $ 174 |
Property Plant and Equipment Jo
Property Plant and Equipment Joint Ownership (Details) $ in Millions | Dec. 31, 2023 USD ($) | |
Jointly Owned Utility Plant Interests [Line Items] | ||
Plant in Service | $ 347 | [1] |
Accumulated Depreciation | 64 | [1] |
CWIP | 1 | |
Jointly Owned Electricity Generation Plant [Member] | La Crosse, Wis. to Madison, Wis. | ||
Jointly Owned Utility Plant Interests [Line Items] | ||
Plant in Service | 178 | |
Accumulated Depreciation | $ 25 | |
Percent Owned | 37% | |
Jointly Owned Electricity Generation Plant [Member] | CapX2020 Transmission | ||
Jointly Owned Utility Plant Interests [Line Items] | ||
Plant in Service | $ 169 | |
Accumulated Depreciation | $ 39 | |
Percent Owned | 80% | |
[1] Projects additionally include $1 million in CWIP. |
Regulatory Assets and Liabili_3
Regulatory Assets and Liabilities, Regulatory Assets (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022 | |
Regulatory Assets [Line Items] | |||
Regulatory Asset, Current | $ 24 | $ 44 | |
Regulatory Asset, Noncurrent | 185 | 193 | |
Environmental Remediation Costs | |||
Regulatory Assets [Line Items] | |||
Regulatory Asset, Current | 13 | 13 | |
Regulatory Asset, Noncurrent | 48 | 63 | |
Pension and Retiree Medical Obligations | |||
Regulatory Assets [Line Items] | |||
Regulatory Asset, Current | 2 | 2 | |
Regulatory Asset, Noncurrent | 62 | 61 | |
Deferred Fuel Costs | |||
Regulatory Assets [Line Items] | |||
Regulatory Asset, Current | 1 | 23 | |
Regulatory Asset, Noncurrent | $ 0 | 0 | |
Deferred Fuel Costs | Maximum | |||
Regulatory Assets [Line Items] | |||
Regulatory Asset, Amortization Period | 1 year | ||
State Commission Adjustments | |||
Regulatory Assets [Line Items] | |||
Regulatory Asset, Current | $ 1 | 1 | |
Regulatory Asset, Noncurrent | 22 | 22 | |
Recoverable Deferred Taxes on AFUDC Recorded in Plant | |||
Regulatory Assets [Line Items] | |||
Regulatory Asset, Current | 0 | 0 | |
Regulatory Asset, Noncurrent | 26 | 20 | |
Asset Retirement Obligation Costs | |||
Regulatory Assets [Line Items] | |||
Regulatory Asset, Current | [1] | 0 | 0 |
Regulatory Asset, Noncurrent | [1] | 21 | 18 |
Other | |||
Regulatory Assets [Line Items] | |||
Regulatory Asset, Current | 7 | 5 | |
Regulatory Asset, Noncurrent | $ 6 | $ 9 | |
[1] Includes amounts recorded for future recovery of AROs, less amounts recovered through NSP-Wisconsin’s share of nuclear decommissioning accruals and gains from decommissioning investments. |
Regulatory Assets and Liabili_4
Regulatory Assets and Liabilities, Regulatory Liabilities (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022 | |
Regulatory Liabilities [Line Items] | |||
Regulatory Liability, Current | $ 42 | $ 21 | |
Regulatory Liability, Noncurrent | 407 | 383 | |
Plant Removal Costs | |||
Regulatory Liabilities [Line Items] | |||
Regulatory Liability, Current | 0 | 0 | |
Regulatory Liability, Noncurrent | 251 | 223 | |
Deferred Income Tax Adjustments and TCJA Refunds | |||
Regulatory Liabilities [Line Items] | |||
Regulatory Liability, Current | [1] | 0 | 0 |
Regulatory Liability, Noncurrent | [1] | 140 | 144 |
United States Department of Energy Settlement | |||
Regulatory Liabilities [Line Items] | |||
Regulatory Liability, Current | 4 | 12 | |
Regulatory Liability, Noncurrent | $ 6 | 3 | |
United States Department of Energy Settlement | Minimum | |||
Regulatory Liabilities [Line Items] | |||
Regulatory liabilities | 1 year | ||
United States Department of Energy Settlement | Maximum | |||
Regulatory Liabilities [Line Items] | |||
Regulatory liabilities | 2 years | ||
Deferred Electric Production And Natural Gas Costs | |||
Regulatory Liabilities [Line Items] | |||
Regulatory Liability, Current | $ 28 | 5 | |
Regulatory Liability, Noncurrent | $ 0 | 0 | |
Deferred Electric Production And Natural Gas Costs | Minimum | |||
Regulatory Liabilities [Line Items] | |||
Regulatory liabilities | 1 year | ||
Other | |||
Regulatory Liabilities [Line Items] | |||
Regulatory Liability, Current | $ 10 | 4 | |
Regulatory Liability, Noncurrent | $ 10 | $ 13 | |
[1] Includes the revaluation of recoverable/regulated plant accumulated deferred income taxes and revaluation impact of non-plant accumulated deferred income taxes due to the TCJA. |
Commercial Paper (Details)
Commercial Paper (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended | ||
Dec. 31, 2023 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | |
Short-term Debt [Line Items] | ||||
Amount outstanding at period end | $ 60 | $ 60 | $ 47 | |
money pool | ||||
Short-term Debt [Line Items] | ||||
Line of Credit Facility, Maximum Borrowing Capacity | 150 | 150 | 150 | $ 150 |
Amount outstanding at period end | 0 | 0 | 0 | 0 |
Average amount outstanding | 7 | 6 | 25 | 16 |
Maximum amount outstanding | $ 43 | $ 43 | $ 81 | $ 78 |
Line of Credit Facility, Interest Rate During Period | 5.34% | 4.98% | 1.10% | 0.05% |
Commercial Paper [Member] | ||||
Short-term Debt [Line Items] | ||||
Line of Credit Facility, Maximum Borrowing Capacity | $ 150 | $ 150 | $ 150 | $ 150 |
Amount outstanding at period end | 60 | 60 | 47 | 83 |
Average amount outstanding | 10 | 15 | 18 | 3 |
Maximum amount outstanding | $ 74 | $ 93 | $ 123 | $ 83 |
Line of Credit Facility, Interest Rate During Period | 5.48% | 4.85% | 1.03% | 0.18% |
Weighted average interest rate at period end (percentage) | 5.50% | 5.50% | 4.55% | 0.21% |
Letters of Credit (Details)
Letters of Credit (Details) - USD ($) $ in Millions | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Line of Credit Facility [Line Items] | ||
Amount outstanding at period end | $ 60 | $ 47 |
Long-term Debt, Current Maturities | $ (200) | 0 |
Series Due May 1, 2051 [Member] | First Mortgage Bonds | ||
Line of Credit Facility [Line Items] | ||
Debt Instrument, Interest Rate, Stated Percentage | 3.05% | |
Debt Instrument, Face Amount | $ 100 | 100 |
Series Due May 1, 2051 2 | First Mortgage Bonds | ||
Line of Credit Facility [Line Items] | ||
Debt Instrument, Interest Rate, Stated Percentage | 2.82% | |
Debt Instrument, Face Amount | $ 100 | 100 |
Letter of Credit | ||
Line of Credit Facility [Line Items] | ||
Amount outstanding at period end | $ 0 | 0 |
Letter of Credit | ||
Line of Credit Facility [Line Items] | ||
Line of Credit Facility, Expiration Period | 1 year | |
Credit Facilities | ||
Line of Credit Facility [Line Items] | ||
Long-term Line of Credit | $ 0 | $ 0 |
Credit Facilities (Details)
Credit Facilities (Details) - Credit Facilities $ in Millions | 12 Months Ended | ||
Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | ||
Line of Credit Facility [Line Items] | |||
Line Of Credit Facility Maximum Debt To Total Capitalization Ratio Allowed | 65% | ||
Line Of Credit Facility Minimum Threshhold Percentage Of Subsidiary Assets To Consolidated Assets Required To Initiate Cross Default Provisions | 15% | ||
Line of Credit Facility, Minimum Amount of Indebtedness in Default to Initiate Cross Default Provisions | $ 75 | ||
Long-term Line of Credit | $ 0 | $ 0 | |
NSP Wisconsin [Member] | |||
Line of Credit Facility [Line Items] | |||
Line Of Credit Facility Debt To Total Capitalization Ratio (as a percent) | [1] | 48.20% | 47.40% |
Credit Facility | [2] | $ 150 | |
Drawn | [3] | 60 | |
Available | $ 90 | ||
Number Of Additional Periods Revolving Termination Date Can Be Extended Subject To Majority Bank Group Approval | [4] | 1 | |
[1] The credit facility has a financial covenant requiring that the debt-to-total capitalization ratio be less than or equal to 65%. This credit facility matures in September 2027. All extension requests are subject to majority bank group approval. |
Long-Term Borrowings and Other
Long-Term Borrowings and Other Financing Instruments (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022 | |
Long-Term Borrowings and Other Financing Instruments | |||
Unamortized discount | $ (3) | $ (3) | |
Unamortized debt expense | (11) | (11) | |
2024 | 200 | ||
2025 | 0 | ||
2026 | 0 | ||
2027 | 0 | ||
2028 | 0 | ||
Long-term Debt | 1,011 | 1,086 | |
Long-term Debt, Current Maturities | $ (200) | 0 | |
Series Due June 15, 2024 [Member] | First Mortgage Bonds | |||
Long-Term Borrowings and Other Financing Instruments | |||
Debt Instrument, Interest Rate, Stated Percentage | 3.30% | ||
Debt Instrument, Face Amount | $ 100 | 100 | |
Series Due June 15, 2024 2 [Member] | First Mortgage Bonds | |||
Long-Term Borrowings and Other Financing Instruments | |||
Debt Instrument, Interest Rate, Stated Percentage | 3.30% | ||
Debt Instrument, Face Amount | $ 100 | 100 | |
Series Due Sept. 1, 2038 [Member] | First Mortgage Bonds | |||
Long-Term Borrowings and Other Financing Instruments | |||
Debt Instrument, Interest Rate, Stated Percentage | 6.375% | ||
Debt Instrument, Face Amount | $ 200 | 200 | |
Series Due Oct. 1, 2042 [Member] | First Mortgage Bonds | |||
Long-Term Borrowings and Other Financing Instruments | |||
Debt Instrument, Interest Rate, Stated Percentage | 3.70% | ||
Debt Instrument, Face Amount | $ 100 | 100 | |
Series Due December 1, 2047 [Member] | First Mortgage Bonds | |||
Long-Term Borrowings and Other Financing Instruments | |||
Debt Instrument, Interest Rate, Stated Percentage | 3.75% | ||
Debt Instrument, Face Amount | $ 100 | 100 | |
Series Due December 1, 2048 [Member] | First Mortgage Bonds | |||
Long-Term Borrowings and Other Financing Instruments | |||
Debt Instrument, Interest Rate, Stated Percentage | 4.20% | ||
Debt Instrument, Face Amount | $ 200 | 200 | |
Series Due May 1, 2051 [Member] | First Mortgage Bonds | |||
Long-Term Borrowings and Other Financing Instruments | |||
Debt Instrument, Interest Rate, Stated Percentage | 3.05% | ||
Debt Instrument, Face Amount | $ 100 | 100 | |
Series Due May 1, 2051 2 | First Mortgage Bonds | |||
Long-Term Borrowings and Other Financing Instruments | |||
Debt Instrument, Interest Rate, Stated Percentage | 2.82% | ||
Debt Instrument, Face Amount | $ 100 | 100 | |
Series Due Sept. 15, 2052 | First Mortgage Bonds | |||
Long-Term Borrowings and Other Financing Instruments | |||
Debt Instrument, Interest Rate, Stated Percentage | [1] | 4.86% | |
Debt Instrument, Face Amount | [1] | $ 100 | 100 |
Series Due June 15, 2053 | First Mortgage Bonds | |||
Long-Term Borrowings and Other Financing Instruments | |||
Debt Instrument, Interest Rate, Stated Percentage | [2] | 5.30% | |
Debt Instrument, Face Amount | [2] | $ 125 | $ 0 |
[1] 2022 financing. 2023 financing. |
Deferred Financing Costs (Detai
Deferred Financing Costs (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022 |
Deferred Financing Costs [Abstract] | ||
Deferred Finance Costs, Noncurrent, Net | $ 11 | $ 11 |
Long-Term Borrowings and Other Financing Instruments | ||
Deferred Finance Costs, Noncurrent, Net | $ 11 | $ 11 |
Dividend and Other Capital-Rela
Dividend and Other Capital-Related Restrictions (Details) $ in Millions | Dec. 31, 2023 USD ($) | |
Dividend and Other Capital-Related Restrictions [Abstract] | ||
Minimum calendar year average equity to total capitalization ratio authorized by state commission | 52.50% | [1] |
Equity to total capitalization ratio | 52.70% | [1] |
Unrestricted Retained Earnings Per State Regulatory Commissions Dividend Restrictions | $ 9 | |
Total Capitalization | $ 2,520 | |
[1] NSP-Wisconsin cannot pay annual dividends in excess of forecasted levels if its average equity-to-total capitalization ratio falls below the commission authorized level. |
Revenues (Details)
Revenues (Details) - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | |
Total revenue from contracts with customers | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | $ 1,162 | $ 1,185 | $ 1,091 |
Retail | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 950 | 975 | 898 |
Retail | Residential | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 383 | 396 | 363 |
Retail | C&I | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 559 | 572 | 526 |
Retail | Other | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 8 | 7 | 9 |
Interchange | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 204 | 202 | 189 |
Other | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 8 | 8 | 4 |
Alternative and Other [Member] | |||
Disaggregation of Revenue [Line Items] | |||
Alternative revenue and other | 15 | 16 | 14 |
Regulated Electric | Total revenue from contracts with customers | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 1,007 | 991 | 910 |
Regulated Electric | Retail | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 800 | 785 | 721 |
Regulated Electric | Retail | Residential | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 299 | 293 | 272 |
Regulated Electric | Retail | C&I | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 494 | 485 | 441 |
Regulated Electric | Retail | Other | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 7 | 7 | 8 |
Regulated Electric | Interchange | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 204 | 202 | 189 |
Regulated Electric | Other | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 3 | 4 | 0 |
Regulated Electric | Alternative and Other [Member] | |||
Disaggregation of Revenue [Line Items] | |||
Alternative revenue and other | 12 | 11 | 12 |
Regulated Natural Gas | Total revenue from contracts with customers | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 154 | 194 | 180 |
Regulated Natural Gas | Retail | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 149 | 190 | 176 |
Regulated Natural Gas | Retail | Residential | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 84 | 103 | 91 |
Regulated Natural Gas | Retail | C&I | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 65 | 87 | 85 |
Regulated Natural Gas | Retail | Other | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 0 | 0 | 0 |
Regulated Natural Gas | Interchange | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 0 | 0 | 0 |
Regulated Natural Gas | Other | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 5 | 4 | 4 |
Regulated Natural Gas | Alternative and Other [Member] | |||
Disaggregation of Revenue [Line Items] | |||
Alternative revenue and other | 3 | 4 | 2 |
All Other | Total revenue from contracts with customers | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 1 | 0 | 1 |
All Other | Retail | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 1 | 0 | 1 |
All Other | Retail | Residential | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 0 | 0 | 0 |
All Other | Retail | C&I | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 0 | 0 | 0 |
All Other | Retail | Other | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 1 | 0 | 1 |
All Other | Interchange | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 0 | 0 | 0 |
All Other | Other | |||
Disaggregation of Revenue [Line Items] | |||
Total revenue from contracts with customers | 0 | 0 | 0 |
All Other | Alternative and Other [Member] | |||
Disaggregation of Revenue [Line Items] | |||
Alternative revenue and other | 0 | 1 | 0 |
Total revenues | |||
Disaggregation of Revenue [Line Items] | |||
Total revenues | 1,177 | 1,201 | 1,105 |
Total revenues | Regulated Electric | |||
Disaggregation of Revenue [Line Items] | |||
Total revenues | 1,019 | 1,002 | 922 |
Total revenues | Regulated Natural Gas | |||
Disaggregation of Revenue [Line Items] | |||
Total revenues | 157 | 198 | 182 |
Total revenues | All Other | |||
Disaggregation of Revenue [Line Items] | |||
Total revenues | $ 1 | $ 1 | $ 1 |
State Audits (Details)
State Audits (Details) | 12 Months Ended |
Dec. 31, 2023 USD ($) | |
WISCONSIN | |
Income Tax Examination [Line Items] | |
Potential Tax Adjustments | $ 0 |
Unrealized Tax Benefits (Detail
Unrealized Tax Benefits (Details) - USD ($) $ in Millions | 12 Months Ended | |||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | |
Income Tax Examination [Line Items] | ||||
Unrecognized tax benefit — Permanent tax positions | $ 3 | $ 2 | ||
Unrecognized tax benefit — Temporary tax positions | 0 | 1 | ||
Total unrecognized tax benefit | 3 | 3 | $ 3 | $ 2 |
Additions for tax positions of prior years | 0 | 0 | 1 | |
NOL and tax credit carryforwards | (2) | (2) | ||
Decrease in Unrecognized Tax Benefits is Reasonably Possible | 1 | |||
Unrecognized Tax Benefits, Income Tax Penalties Expense | $ 0 | $ 0 | $ 0 |
Other Income Tax Matters (Detai
Other Income Tax Matters (Details) - USD ($) $ in Millions | 12 Months Ended | ||||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | |||
Income Tax Examination [Line Items] | |||||
Tax Credit Carryforward, Amount | $ 3 | $ 7 | |||
State NOL carryforward | $ 2 | $ 2 | |||
Federal statutory rate | 21% | 21% | 21% | ||
State income tax on pretax income, net of federal tax effect | 6.20% | 6.20% | 6.20% | ||
Plant regulatory differences (a) | [1] | (3.40%) | (3.80%) | (4.10%) | |
Other tax credits, net NOL & tax credit allowances | (0.60%) | (0.80%) | (1.00%) | ||
Other, net | (0.50%) | (0.70%) | (0.40%) | ||
Effective income tax rate | 22.70% | 21.90% | 21.70% | ||
Total income tax expense | $ 40 | $ 35 | $ 30 | ||
Deferred tax (benefit) expense excluding items below | (3) | 8 | 18 | ||
Amortization and adjustments to deferred income taxes on income tax regulatory assets and liabilities | (10) | (10) | (10) | ||
Deferred tax (benefit) expense | 12 | 2 | 9 | ||
Environmental remediation | 4 | 4 | [2] | ||
Other | 1 | 0 | 1 | ||
Deferred Finance Costs, Noncurrent, Net | 11 | 11 | |||
Credit Facilities | |||||
Income Tax Examination [Line Items] | |||||
Long-term Line of Credit | 0 | 0 | |||
income tax expense [Member] | |||||
Income Tax Examination [Line Items] | |||||
Current federal tax expense | 37 | 28 | 17 | ||
Current state tax expense | 15 | 9 | 4 | ||
Deferred federal tax (benefit) expense | (10) | (5) | 3 | ||
Deferred state tax (benefit) expense | (3) | 3 | 6 | ||
Total income tax expense | 40 | 35 | 30 | ||
Deferred Change In Unrecognized Tax Expense Benefit | 1 | 0 | $ 0 | ||
Net Deferred Tax Liablility [Member] | |||||
Income Tax Examination [Line Items] | |||||
Tax Credit Carryforward, Amount | 3 | 7 | [2] | ||
Deferred tax (benefit) expense | 59 | 58 | [2] | ||
Difference between book and tax bases of property | 350 | 343 | [2] | ||
Regulatory assets | 22 | 24 | [2] | ||
Pension expense | 10 | 10 | [2] | ||
Deferred fuel costs | 0 | 6 | [2] | ||
Other | 7 | 8 | [2] | ||
Total deferred tax liabilities | 389 | 391 | [2] | ||
Regulatory liabilities | 32 | 35 | [2] | ||
Other employee benefits | 4 | 3 | [2] | ||
Deferred Tax Assets Rate Refund | 10 | 3 | [2] | ||
Deferred ITCs | 2 | 2 | [2] | ||
Other | 4 | 4 | [2] | ||
Net deferred tax liability | $ 330 | $ 333 | [2] | ||
[1] Plant regulatory differences primarily relate to the credit of excess deferred taxes to customers through the average rate assumption method. Income tax benefits associated with the credit are offset by corresponding revenue reductions. |
Interest Rate Derivatives (Deta
Interest Rate Derivatives (Details) $ in Millions | Dec. 31, 2023 USD ($) |
Cash Flow Hedges | |
Interest Rate Derivatives [Abstract] | |
Derivative Instruments in Hedges, at Fair Value, Net | $ 0 |
Impact of Derivative Activities
Impact of Derivative Activities on Income (Details) - USD ($) | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 |
Derivative [Line Items] | |||
Fair Value Hedges, Net | $ 0 | $ 0 | $ 0 |
Recurring Fair Value Measuremen
Recurring Fair Value Measurement (Details) - USD ($) | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 |
Derivatives, Fair Value [Line Items] | |||
Prepayments and other | $ 6,000,000 | $ 11,000,000 | |
Other Liabilities, Noncurrent | 35,000,000 | 43,000,000 | |
Fair Value Hedges, Net | $ 0 | $ 0 | $ 0 |
Fair Value of Long-Term Debt (D
Fair Value of Long-Term Debt (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022 |
Derivatives, Fair Value [Line Items] | ||
Long-term debt, Fair Value | $ 1,117 | $ 980 |
Long-term Debt, Gross | $ 1,211 | $ 1,086 |
Fair Value of Financial Asset_3
Fair Value of Financial Assets and Liabilities Fair Value Phantom (Details) - USD ($) | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 |
Fair Value Disclosures [Abstract] | |||
Fair Value Hedges, Net | $ 0 | $ 0 | $ 0 |
Benefit Plans and Other Postr_3
Benefit Plans and Other Postretirement Benefits, Pension Benefits (Details) - USD ($) | 1 Months Ended | 12 Months Ended | |||
Jan. 31, 2024 | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | |
Defined Benefit Plan Disclosure [Line Items] | |||||
Operating and maintenance expenses | $ 239,000,000 | $ 223,000,000 | $ 198,000,000 | ||
Target Pension Asset Allocations [Abstract] | |||||
annual interest crediting rates [Domain] | 4.67 | 4.86 | 1.96 | ||
annual interest crediting rates [Domain] | 4.67 | 4.86 | 1.96 | ||
Pension Plan [Member] | |||||
Defined Benefit Plan Disclosure [Line Items] | |||||
Operating and maintenance expenses | 1,000,000 | ||||
Pension Benefits [Abstract] | |||||
Total benefit obligation | 112,000,000 | 112,000,000 | 141,000,000 | ||
Net benefit cost recognized for financial reporting | $ 4,000,000 | $ 8,000,000 | $ 8,000,000 | ||
Expected average long-term rate of return on assets (as a percent) | 7.25% | 6.60% | 6.60% | ||
Target Pension Asset Allocations [Abstract] | |||||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 100% | 100% | |||
Pension Plan [Member] | Subsequent Event | |||||
Target Pension Asset Allocations [Abstract] | |||||
Payment for Pension Benefits | $ 100,000,000 | ||||
Pension Plan [Member] | Long-duration fixed income and interest rate swap securities | |||||
Target Pension Asset Allocations [Abstract] | |||||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 38% | 38% | |||
Pension Plan [Member] | Domestic and international equity securities | |||||
Target Pension Asset Allocations [Abstract] | |||||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 31% | 33% | |||
Pension Plan [Member] | Alternative investments | |||||
Target Pension Asset Allocations [Abstract] | |||||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 20% | 18% | |||
Pension Plan [Member] | Short-to-intermediate fixed income securities | |||||
Target Pension Asset Allocations [Abstract] | |||||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 9% | 9% | |||
Pension Plan [Member] | Cash | |||||
Target Pension Asset Allocations [Abstract] | |||||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 2% | 2% | |||
Forecast [Member] | Pension Plan [Member] | |||||
Pension Benefits [Abstract] | |||||
Expected average long-term rate of return on assets for next fiscal year (as a percent) | 7.25% | ||||
Parent Company [Member] | Supplemental Executive Retirement Plan (SERP) and Nonqualified Pension Plan | |||||
Pension Benefits [Abstract] | |||||
Total benefit obligation | $ 12,000,000 | $ 11,000,000 | |||
Net benefit cost recognized for financial reporting | $ 2,000,000 | $ 17,000,000 |
Benefit Plans and Other Postr_4
Benefit Plans and Other Postretirement Benefits, Fair Value of Pension Plan Assets (Details) - USD ($) $ in Millions | 12 Months Ended | ||||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | |||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
assets transferred | $ 0 | $ 0 | |||
Pension Plan [Member] | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | 95 | [1] | 97 | $ 137 | |
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement | [2] | 0 | (6) | (5) | |
Pension Plan [Member] | NSP Wisconsin [Member] | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 97 | |||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement | (5) | 0 | |||
Pension Plan [Member] | Level 1 | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 28 | 41 | ||
Pension Plan [Member] | Level 2 | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 22 | 22 | ||
Pension Plan [Member] | Level 3 | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 0 | 0 | ||
Pension Plan [Member] | Fair Value Measured at Net Asset Value Per Share | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Plan assets at net asset value | [1] | 45 | 34 | ||
Pension Plan [Member] | Cash equivalents | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 8 | 4 | ||
Pension Plan [Member] | Cash equivalents | Level 1 | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 8 | 4 | ||
Pension Plan [Member] | Cash equivalents | Level 2 | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 0 | 0 | ||
Pension Plan [Member] | Cash equivalents | Level 3 | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 0 | 0 | ||
Pension Plan [Member] | Cash equivalents | Fair Value Measured at Net Asset Value Per Share | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Plan assets at net asset value | [1] | 0 | 0 | ||
Pension Plan [Member] | Commingled funds | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 64 | 69 | ||
Pension Plan [Member] | Commingled funds | Level 1 | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 19 | 35 | ||
Pension Plan [Member] | Commingled funds | Level 2 | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 0 | 0 | ||
Pension Plan [Member] | Commingled funds | Level 3 | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 0 | 0 | ||
Pension Plan [Member] | Commingled funds | Fair Value Measured at Net Asset Value Per Share | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Plan assets at net asset value | [1] | 45 | 34 | ||
Pension Plan [Member] | Debt Securities [Member] | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 22 | 22 | ||
Pension Plan [Member] | Debt Securities [Member] | Level 1 | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 0 | 0 | ||
Pension Plan [Member] | Debt Securities [Member] | Level 2 | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 22 | 22 | ||
Pension Plan [Member] | Debt Securities [Member] | Level 3 | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 0 | 0 | ||
Pension Plan [Member] | Debt Securities [Member] | Fair Value Measured at Net Asset Value Per Share | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Plan assets at net asset value | [1] | 0 | 0 | ||
Pension Plan [Member] | Domestic and international equity securities | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 1 | 2 | ||
Pension Plan [Member] | Domestic and international equity securities | Level 1 | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 1 | 2 | ||
Pension Plan [Member] | Domestic and international equity securities | Level 2 | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 0 | 0 | ||
Pension Plan [Member] | Domestic and international equity securities | Level 3 | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | [1] | 0 | 0 | ||
Pension Plan [Member] | Domestic and international equity securities | Fair Value Measured at Net Asset Value Per Share | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Plan assets at net asset value | [1] | 0 | 0 | ||
Other Postretirement Benefits Plan [Member] | |||||
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||||
Fair value of plan assets | 0 | 0 | 0 | ||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement | [2] | $ 0 | $ 0 | $ 0 | |
[1] See Note 8 for further information on fair value measurement inputs and methods. A settlement charge is required when the amount of all lump-sum distributions during the year is greater than the sum of the service and interest cost components of the annual net periodic pension cost. There were no settlement charges recorded to the qualified pension plans in 2023. In 2022, as a result of lump-sum distributions during the plan years, NSP-Wisconsin recorded a total pension settlement charge of $5 million, of which $1 million was recorded in the income statement. |
Benefit Plans and Other Postr_5
Benefit Plans and Other Postretirement Benefits, Pension Plan Benefit Obligations, Cash Flows and Benefit Costs (Details) | 1 Months Ended | 12 Months Ended | |||||
Jan. 31, 2024 USD ($) | Dec. 31, 2023 USD ($) Plan | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | ||||
Components of Net Periodic Benefit Cost (Credit) [Abstract] | |||||||
Settlement Charge Recognized in Operating and Maintenance Expenses | $ 239,000,000 | $ 223,000,000 | $ 198,000,000 | ||||
Significant Assumptions Used to Measure Costs [Abstract] | |||||||
Liability, Defined Benefit Plan, Noncurrent | (27,000,000) | (23,000,000) | |||||
Pension Plan [Member] | |||||||
Defined Benefit Plan Disclosure [Line Items] | |||||||
Accumulated Benefit Obligation at Dec. 31 | 100,000,000 | 101,000,000 | |||||
Change in Projected Benefit Obligation [Roll Forward] | |||||||
Obligation at Jan. 1 | $ 112,000,000 | 112,000,000 | 141,000,000 | ||||
Service cost | 4,000,000 | 5,000,000 | 5,000,000 | ||||
Interest cost | 6,000,000 | 4,000,000 | 4,000,000 | ||||
Actuarial loss | 1,000,000 | (21,000,000) | |||||
Benefit payments | (11,000,000) | (17,000,000) | |||||
Obligation at Dec. 31 | 112,000,000 | 112,000,000 | 141,000,000 | ||||
Change in Fair Value of Plan Assets [Roll Forward] | |||||||
Fair value of plan assets at Jan. 1 | 95,000,000 | [1] | 97,000,000 | 137,000,000 | |||
Actual return (loss) on plan assets | 5,000,000 | (24,000,000) | |||||
Employer contributions | 4,000,000 | 1,000,000 | |||||
Benefit payments | (11,000,000) | (17,000,000) | |||||
Fair value of plan assets at Dec. 31 | 95,000,000 | [1] | 97,000,000 | 137,000,000 | |||
Funded Status of Plans at Dec. 31 [Abstract] | |||||||
Funded status | (17,000,000) | (15,000,000) | |||||
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost [Abstract] | |||||||
Net loss | 48,000,000 | 45,000,000 | |||||
Prior service (credit) cost | 0 | 0 | |||||
Total | 48,000,000 | 45,000,000 | |||||
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost Have Been Recorded as Follows Based Upon Expected Recovery in Rates [Abstract] | |||||||
Current regulatory assets | 2,000,000 | 1,000,000 | |||||
Noncurrent regulatory assets | 46,000,000 | 44,000,000 | |||||
Total | $ 48,000,000 | $ 45,000,000 | |||||
Significant Assumptions Used to Measure Benefit Obligations [Abstract] | |||||||
Discount rate for year-end valuation (as a percent) | 5.49% | 5.80% | |||||
Expected average long-term increase in compensation level (as a percent) | 4.25% | 4.25% | |||||
Components of Net Periodic Benefit Cost (Credit) [Abstract] | |||||||
Service cost | $ 4,000,000 | $ 5,000,000 | 5,000,000 | ||||
Interest cost | 6,000,000 | 4,000,000 | 4,000,000 | ||||
Expected return on plan assets | (8,000,000) | (8,000,000) | (8,000,000) | ||||
Amortization of net loss | 2,000,000 | 3,000,000 | 5,000,000 | ||||
Settlement charge | [2] | 0 | 6,000,000 | 5,000,000 | |||
Net periodic benefit cost | 4,000,000 | 10,000,000 | 11,000,000 | ||||
Net benefit cost recognized for financial reporting | $ 4,000,000 | 8,000,000 | $ 8,000,000 | ||||
Settlement Charge Recognized in Operating and Maintenance Expenses | $ 1,000,000 | ||||||
Significant Assumptions Used to Measure Costs [Abstract] | |||||||
Discount rate (as a percent) | 5.80% | 3.08% | 2.71% | ||||
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase | 4.25% | 3.75% | 3.75% | ||||
Liability, Defined Benefit Plan, Current | $ 0 | $ 0 | |||||
Liability, Defined Benefit Plan, Noncurrent | (17,000,000) | (15,000,000) | |||||
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position | (17,000,000) | (15,000,000) | |||||
Defined Benefit Plan Credits (Costs) Not Recognized Due To Effects of Regulation | $ 0 | $ 2,000,000 | $ 3,000,000 | ||||
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets | 7.25% | 6.60% | 6.60% | ||||
Pension Plan [Member] | NSP Wisconsin [Member] | |||||||
Change in Fair Value of Plan Assets [Roll Forward] | |||||||
Fair value of plan assets at Jan. 1 | [1] | $ 97,000,000 | |||||
Fair value of plan assets at Dec. 31 | [1] | $ 97,000,000 | |||||
Cash Flows [Abstract] | |||||||
Payment for Pension Benefits | 4,000,000 | 1,000,000 | $ 5,000,000 | ||||
Components of Net Periodic Benefit Cost (Credit) [Abstract] | |||||||
Settlement charge | 5,000,000 | 0 | |||||
Other Postretirement Benefits Plan [Member] | |||||||
Change in Projected Benefit Obligation [Roll Forward] | |||||||
Obligation at Jan. 1 | 8,000,000 | 8,000,000 | 11,000,000 | ||||
Service cost | 0 | 0 | 0 | ||||
Interest cost | 1,000,000 | 1,000,000 | 1,000,000 | ||||
Actuarial loss | 0 | (3,000,000) | |||||
Benefit payments | (1,000,000) | (1,000,000) | |||||
Obligation at Dec. 31 | 8,000,000 | 8,000,000 | 11,000,000 | ||||
Change in Fair Value of Plan Assets [Roll Forward] | |||||||
Fair value of plan assets at Jan. 1 | 0 | 0 | 0 | ||||
Actual return (loss) on plan assets | 0 | 0 | |||||
Employer contributions | 1,000,000 | 1,000,000 | |||||
Benefit payments | (1,000,000) | (1,000,000) | |||||
Fair value of plan assets at Dec. 31 | 0 | 0 | 0 | ||||
Funded Status of Plans at Dec. 31 [Abstract] | |||||||
Funded status | (8,000,000) | (8,000,000) | |||||
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost [Abstract] | |||||||
Net loss | 3,000,000 | 4,000,000 | |||||
Prior service (credit) cost | 0 | 0 | |||||
Total | 3,000,000 | 4,000,000 | |||||
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost Have Been Recorded as Follows Based Upon Expected Recovery in Rates [Abstract] | |||||||
Current regulatory assets | 0 | ||||||
Noncurrent regulatory assets | 3,000,000 | 4,000,000 | |||||
Total | $ 3,000,000 | $ 4,000,000 | |||||
Significant Assumptions Used to Measure Benefit Obligations [Abstract] | |||||||
Discount rate for year-end valuation (as a percent) | 5.54% | 5.80% | |||||
Components of Net Periodic Benefit Cost (Credit) [Abstract] | |||||||
Service cost | $ 0 | $ 0 | 0 | ||||
Interest cost | 1,000,000 | 1,000,000 | 1,000,000 | ||||
Expected return on plan assets | 0 | 0 | 0 | ||||
Amortization of net loss | 0 | 0 | 0 | ||||
Settlement charge | [2] | 0 | 0 | 0 | |||
Net periodic benefit cost | 1,000,000 | 1,000,000 | 1,000,000 | ||||
Net benefit cost recognized for financial reporting | $ 1,000,000 | $ 1,000,000 | $ 1,000,000 | ||||
Significant Assumptions Used to Measure Costs [Abstract] | |||||||
Discount rate (as a percent) | 5.80% | 3.09% | 2.65% | ||||
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase | 0% | 0% | 0% | ||||
Liability, Defined Benefit Plan, Current | $ 1,000,000 | $ 0 | |||||
Liability, Defined Benefit Plan, Noncurrent | (7,000,000) | (8,000,000) | |||||
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position | $ (8,000,000) | $ (8,000,000) | |||||
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Pre-65 | 6.50% | 6.50% | |||||
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Post-65 | 5.50% | 5.50% | |||||
Ultimate health care trend assumption rate (as a percent) | 4.50% | 4.50% | |||||
Period until ultimate trend rate is reached (in years) | $ 6 | $ 7 | |||||
Defined Benefit Plan Credits (Costs) Not Recognized Due To Effects of Regulation | $ 0 | $ 0 | |||||
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets | 5% | 4.10% | 4.10% | ||||
Subsequent Event | Pension Plan [Member] | |||||||
Cash Flows [Abstract] | |||||||
Payment for Pension Benefits | 100,000,000 | ||||||
Subsequent Event | Pension Plan [Member] | NSP Wisconsin [Member] | |||||||
Cash Flows [Abstract] | |||||||
Payment for Pension Benefits | $ 7,000,000 | ||||||
Parent Company [Member] | Pension Plan [Member] | |||||||
Cash Flows [Abstract] | |||||||
Number of pension plans to which contributions were made | Plan | 4 | ||||||
[1] See Note 8 for further information on fair value measurement inputs and methods. A settlement charge is required when the amount of all lump-sum distributions during the year is greater than the sum of the service and interest cost components of the annual net periodic pension cost. There were no settlement charges recorded to the qualified pension plans in 2023. In 2022, as a result of lump-sum distributions during the plan years, NSP-Wisconsin recorded a total pension settlement charge of $5 million, of which $1 million was recorded in the income statement. |
Benefit Plans and Other Postr_6
Benefit Plans and Other Postretirement Benefits, Defined Contribution Plans (Details) - USD ($) | 12 Months Ended | |||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | ||
Defined Benefit Plan Disclosure [Line Items] | ||||
Defined Contribution Plan, Administrative Expense | $ 2,000,000 | $ 2,000,000 | $ 2,000,000 | |
Other Postretirement Benefits Plan [Member] | ||||
Defined Benefit Plan Disclosure [Line Items] | ||||
Discount rate for year-end valuation (as a percent) | 5.54% | 5.80% | ||
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Pre-65 | 6.50% | 6.50% | ||
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Post-65 | 5.50% | 5.50% | ||
Ultimate health care trend assumption rate (as a percent) | 4.50% | 4.50% | ||
Period until ultimate trend rate is reached (in years) | $ 6 | $ 7 | ||
Net benefit cost recognized for financial reporting | 1,000,000 | 1,000,000 | 1,000,000 | |
Settlement charge | [1] | $ 0 | $ 0 | 0 |
Pension Plan [Member] | ||||
Defined Benefit Plan Disclosure [Line Items] | ||||
Discount rate for year-end valuation (as a percent) | 5.49% | 5.80% | ||
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase | 4.25% | 4.25% | ||
Net benefit cost recognized for financial reporting | $ 4,000,000 | $ 8,000,000 | 8,000,000 | |
Settlement charge | [1] | 0 | 6,000,000 | 5,000,000 |
Pension Plan [Member] | NSP Wisconsin [Member] | ||||
Defined Benefit Plan Disclosure [Line Items] | ||||
Settlement charge | 5,000,000 | $ 0 | ||
Supplemental Executive Retirement Plan (SERP) and Nonqualified Pension Plan | Parent Company [Member] | ||||
Defined Benefit Plan Disclosure [Line Items] | ||||
Net benefit cost recognized for financial reporting | $ 2,000,000 | $ 17,000,000 | ||
[1] A settlement charge is required when the amount of all lump-sum distributions during the year is greater than the sum of the service and interest cost components of the annual net periodic pension cost. There were no settlement charges recorded to the qualified pension plans in 2023. In 2022, as a result of lump-sum distributions during the plan years, NSP-Wisconsin recorded a total pension settlement charge of $5 million, of which $1 million was recorded in the income statement. |
Benefit Plans and Other Postr_7
Benefit Plans and Other Postretirement Benefits, Postretirement Health Care Benefits (Details) $ in Millions | Dec. 31, 2023 USD ($) Employees | Dec. 31, 2022 USD ($) |
Postretirement Health Care Benefits [Abstract] | ||
Estimated costs of health plan subsidies - VRP | $ | $ 2 | |
Estimated cost of other medical benefits - VRP | $ | $ 0 | |
Voluntary Retirement Program | Xcel Energy [Member] | ||
Postretirement Health Care Benefits [Abstract] | ||
Entity Number of Employees | Employees | 400 | |
Employee Severance | Xcel Energy [Member] | ||
Postretirement Health Care Benefits [Abstract] | ||
Entity Number of Employees | Employees | 150 | |
Other Postretirement Benefits Plan [Member] | ||
Postretirement Health Care Benefits [Abstract] | ||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 100% | 100% |
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate, VRP | 0.0550 | |
Defined Benefit Plan, Health Care Cost Trend Rate Assumed and Ultimate Trend Assumption, VRP | 0.0700 | |
Pension Plan [Member] | ||
Postretirement Health Care Benefits [Abstract] | ||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 100% | 100% |
Domestic and international equity securities | Other Postretirement Benefits Plan [Member] | ||
Postretirement Health Care Benefits [Abstract] | ||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 9% | 16% |
Domestic and international equity securities | Pension Plan [Member] | ||
Postretirement Health Care Benefits [Abstract] | ||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 31% | 33% |
Short-to-intermediate fixed income securities | Other Postretirement Benefits Plan [Member] | ||
Postretirement Health Care Benefits [Abstract] | ||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 77% | 71% |
Short-to-intermediate fixed income securities | Pension Plan [Member] | ||
Postretirement Health Care Benefits [Abstract] | ||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 9% | 9% |
Alternative investments | Other Postretirement Benefits Plan [Member] | ||
Postretirement Health Care Benefits [Abstract] | ||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 13% | 12% |
Alternative investments | Pension Plan [Member] | ||
Postretirement Health Care Benefits [Abstract] | ||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 20% | 18% |
Cash | Other Postretirement Benefits Plan [Member] | ||
Postretirement Health Care Benefits [Abstract] | ||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 1% | 1% |
Cash | Pension Plan [Member] | ||
Postretirement Health Care Benefits [Abstract] | ||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 2% | 2% |
Benefit Plans and Other Postr_8
Benefit Plans and Other Postretirement Benefits, Fair Value of Postretirement Benefit Plan Assets (Details) - Other Postretirement Benefits Plan [Member] - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | |
Defined Benefit Plan Disclosure [Line Items] | |||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 100% | 100% | |
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract] | |||
Fair value of plan assets | $ 0 | $ 0 | $ 0 |
Defined Benefit Plan, Expected Return (Loss) on Plan Assets | $ 0 | $ 0 | $ 0 |
Cash equivalents | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 1% | 1% | |
Domestic and international equity securities | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 9% | 16% | |
Long-duration fixed income and interest rate swap securities | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 0% | 0% | |
Short-to-intermediate fixed income securities | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 77% | 71% | |
Alternative investments | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 13% | 12% |
Benefit Plans and Other Postr_9
Benefit Plans and Other Postretirement Benefits, Postretirement Benefit Plan Benefit Obligations, Cash Flows and Benefit Costs (Details) - USD ($) | 1 Months Ended | 12 Months Ended | |||||
Jan. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | ||||
Funded Status of Plans at Dec. 31 [Abstract] | |||||||
Noncurrent liabilities | $ (27,000,000) | $ (23,000,000) | |||||
Pension Plan [Member] | |||||||
Change in Projected Benefit Obligation [Roll Forward] | |||||||
Obligation at Jan. 1 | $ 112,000,000 | 112,000,000 | 141,000,000 | ||||
Service cost | 4,000,000 | 5,000,000 | $ 5,000,000 | ||||
Interest cost | 6,000,000 | 4,000,000 | 4,000,000 | ||||
Actuarial loss | 1,000,000 | (21,000,000) | |||||
Benefit payments | (11,000,000) | (17,000,000) | |||||
Obligation at Dec. 31 | 112,000,000 | 112,000,000 | 141,000,000 | ||||
Change in Fair Value of Plan Assets [Roll Forward] | |||||||
Fair value of plan assets at Jan. 1 | 95,000,000 | [1] | 97,000,000 | 137,000,000 | |||
Actual return (loss) on plan assets | 5,000,000 | (24,000,000) | |||||
Employer contributions | 4,000,000 | 1,000,000 | |||||
Benefit payments | (11,000,000) | (17,000,000) | |||||
Fair value of plan assets at Dec. 31 | 95,000,000 | [1] | 97,000,000 | 137,000,000 | |||
Funded Status of Plans at Dec. 31 [Abstract] | |||||||
Funded status | (17,000,000) | (15,000,000) | |||||
Current liabilities | 0 | 0 | |||||
Noncurrent liabilities | (17,000,000) | (15,000,000) | |||||
Net postretirement amounts recognized on consolidated balance sheets | (17,000,000) | (15,000,000) | |||||
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost [Abstract] | |||||||
Net loss | 48,000,000 | 45,000,000 | |||||
Prior service (credit) cost | 0 | 0 | |||||
Total | 48,000,000 | 45,000,000 | |||||
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost Have Been Recorded as Follows Based Upon Expected Recovery in Rates [Abstract] | |||||||
Current regulatory assets | 2,000,000 | 1,000,000 | |||||
Noncurrent regulatory assets | 46,000,000 | 44,000,000 | |||||
Total | $ 48,000,000 | $ 45,000,000 | |||||
Significant Assumptions Used to Measure Benefit Obligations [Abstract] | |||||||
Discount rate for year-end valuation (as a percent) | 5.49% | 5.80% | |||||
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase | 4.25% | 4.25% | |||||
Components of Net Periodic Benefit Cost (Credit) [Abstract] | |||||||
Service cost | $ 4,000,000 | $ 5,000,000 | 5,000,000 | ||||
Interest cost | 6,000,000 | 4,000,000 | 4,000,000 | ||||
Expected return on plan assets | (8,000,000) | (8,000,000) | (8,000,000) | ||||
Amortization of net loss | 2,000,000 | 3,000,000 | 5,000,000 | ||||
Settlement charge | [2] | 0 | 6,000,000 | 5,000,000 | |||
Net periodic benefit cost | $ 4,000,000 | $ 10,000,000 | $ 11,000,000 | ||||
Significant Assumptions Used to Measure Costs [Abstract] | |||||||
Discount rate (as a percent) | 5.80% | 3.08% | 2.71% | ||||
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase | 4.25% | 3.75% | 3.75% | ||||
Expected average long-term rate of return on assets (as a percent) | 7.25% | 6.60% | 6.60% | ||||
Defined Benefit Plan Credits (Costs) Not Recognized Due To Effects of Regulation | $ 0 | $ (2,000,000) | $ (3,000,000) | ||||
Net benefit cost recognized for financial reporting | 4,000,000 | 8,000,000 | 8,000,000 | ||||
Other Postretirement Benefits Plan [Member] | |||||||
Change in Projected Benefit Obligation [Roll Forward] | |||||||
Obligation at Jan. 1 | 8,000,000 | 8,000,000 | 11,000,000 | ||||
Service cost | 0 | 0 | 0 | ||||
Interest cost | 1,000,000 | 1,000,000 | 1,000,000 | ||||
Actuarial loss | 0 | (3,000,000) | |||||
Benefit payments | (1,000,000) | (1,000,000) | |||||
Obligation at Dec. 31 | 8,000,000 | 8,000,000 | 11,000,000 | ||||
Change in Fair Value of Plan Assets [Roll Forward] | |||||||
Fair value of plan assets at Jan. 1 | 0 | 0 | 0 | ||||
Actual return (loss) on plan assets | 0 | 0 | |||||
Employer contributions | 1,000,000 | 1,000,000 | |||||
Benefit payments | (1,000,000) | (1,000,000) | |||||
Fair value of plan assets at Dec. 31 | 0 | 0 | 0 | ||||
Funded Status of Plans at Dec. 31 [Abstract] | |||||||
Funded status | (8,000,000) | (8,000,000) | |||||
Current liabilities | (1,000,000) | 0 | |||||
Noncurrent liabilities | (7,000,000) | (8,000,000) | |||||
Net postretirement amounts recognized on consolidated balance sheets | (8,000,000) | (8,000,000) | |||||
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost [Abstract] | |||||||
Net loss | 3,000,000 | 4,000,000 | |||||
Prior service (credit) cost | 0 | 0 | |||||
Total | 3,000,000 | 4,000,000 | |||||
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost Have Been Recorded as Follows Based Upon Expected Recovery in Rates [Abstract] | |||||||
Current regulatory assets | 0 | ||||||
Noncurrent regulatory assets | 3,000,000 | 4,000,000 | |||||
Total | $ 3,000,000 | $ 4,000,000 | |||||
Significant Assumptions Used to Measure Benefit Obligations [Abstract] | |||||||
Discount rate for year-end valuation (as a percent) | 5.54% | 5.80% | |||||
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Pre-65 | 6.50% | 6.50% | |||||
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Post-65 | 5.50% | 5.50% | |||||
Ultimate health care trend assumption rate (as a percent) | 4.50% | 4.50% | |||||
Period until ultimate trend rate is reached (in years) | $ 6 | $ 7 | |||||
Components of Net Periodic Benefit Cost (Credit) [Abstract] | |||||||
Service cost | 0 | 0 | 0 | ||||
Interest cost | 1,000,000 | 1,000,000 | 1,000,000 | ||||
Expected return on plan assets | 0 | 0 | 0 | ||||
Amortization of net loss | 0 | 0 | 0 | ||||
Settlement charge | [2] | 0 | 0 | 0 | |||
Net periodic benefit cost | $ 1,000,000 | $ 1,000,000 | $ 1,000,000 | ||||
Significant Assumptions Used to Measure Costs [Abstract] | |||||||
Discount rate (as a percent) | 5.80% | 3.09% | 2.65% | ||||
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase | 0% | 0% | 0% | ||||
Expected average long-term rate of return on assets (as a percent) | 5% | 4.10% | 4.10% | ||||
Defined Benefit Plan Credits (Costs) Not Recognized Due To Effects of Regulation | $ 0 | $ 0 | |||||
Net benefit cost recognized for financial reporting | $ 1,000,000 | $ 1,000,000 | $ 1,000,000 | ||||
Subsequent Event | Pension Plan [Member] | |||||||
Defined Benefit Plan Disclosure [Line Items] | |||||||
Payment for Pension Benefits | $ 100,000,000 | ||||||
[1] See Note 8 for further information on fair value measurement inputs and methods. A settlement charge is required when the amount of all lump-sum distributions during the year is greater than the sum of the service and interest cost components of the annual net periodic pension cost. There were no settlement charges recorded to the qualified pension plans in 2023. In 2022, as a result of lump-sum distributions during the plan years, NSP-Wisconsin recorded a total pension settlement charge of $5 million, of which $1 million was recorded in the income statement. |
Benefit Plans and Other Post_10
Benefit Plans and Other Postretirement Benefits, Projected Benefit Payments (Details) - USD ($) $ in Millions | 1 Months Ended | 12 Months Ended | |||
Jan. 31, 2024 | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | |
Defined Benefit Plan, Net Projected Benefit Payments [Abstract] | |||||
Defined Contribution Plan, Administrative Expense | $ 2 | $ 2 | $ 2 | ||
Pension Plan [Member] | |||||
Defined Benefit Plan, Gross Projected Benefit Payments [Abstract] | |||||
2021 | 17 | ||||
2022 | 8 | ||||
2023 | 8 | ||||
2024 | 9 | ||||
2025 | 10 | ||||
2026-2030 | 51 | ||||
Pension Plan [Member] | NSP Wisconsin [Member] | |||||
Defined Benefit Plan, Net Projected Benefit Payments [Abstract] | |||||
Payment for Pension Benefits | 4 | 1 | 5 | ||
Pension Plan [Member] | Xcel Energy [Member] | |||||
Defined Benefit Plan, Net Projected Benefit Payments [Abstract] | |||||
Payment for Pension Benefits | 50 | 50 | 131 | ||
Pension Plan [Member] | Subsequent Event | |||||
Defined Benefit Plan, Net Projected Benefit Payments [Abstract] | |||||
Payment for Pension Benefits | $ 100 | ||||
Pension Plan [Member] | Subsequent Event | NSP Wisconsin [Member] | |||||
Defined Benefit Plan, Net Projected Benefit Payments [Abstract] | |||||
Payment for Pension Benefits | $ 7 | ||||
Other Postretirement Benefits Plan [Member] | |||||
Defined Benefit Plan, Gross Projected Benefit Payments [Abstract] | |||||
2021 | 1 | ||||
2022 | 1 | ||||
2023 | 1 | ||||
2024 | 1 | ||||
2025 | 1 | ||||
2026-2030 | 3 | ||||
Defined Benefit Plan, Overfunded Plan [Member] | NSP Wisconsin [Member] | |||||
Defined Benefit Plan, Net Projected Benefit Payments [Abstract] | |||||
Payment for Pension Benefits | 0 | 1 | 2 | ||
Defined Benefit Plan, Overfunded Plan [Member] | Xcel Energy [Member] | |||||
Defined Benefit Plan, Net Projected Benefit Payments [Abstract] | |||||
Payment for Pension Benefits | $ 11 | $ 13 | $ 15 | ||
Defined Benefit Plan, Overfunded Plan [Member] | Subsequent Event | NSP Wisconsin [Member] | |||||
Defined Benefit Plan, Net Projected Benefit Payments [Abstract] | |||||
Payment for Pension Benefits | $ 1 | ||||
Defined Benefit Plan, Overfunded Plan [Member] | Subsequent Event | Xcel Energy [Member] | |||||
Defined Benefit Plan, Net Projected Benefit Payments [Abstract] | |||||
Payment for Pension Benefits | $ 11 |
Commitments and Contingencies M
Commitments and Contingencies MISO ROE Complaints (Details) - Federal Energy Regulatory Commission (FERC) [Member] - NSP Minnesota and NSP Wisconsin [Member] [Member] - FERC Proceeding, MISO ROE Complaint [Member] | 1 Months Ended | |
Feb. 28, 2015 | Nov. 30, 2013 | |
Public Utilities, General Disclosures [Line Items] | ||
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% |
Commitments and Contingencies_2
Commitments and Contingencies MGP Sites (Details) - Other MGP, Landfill, or Disposal Sites | Dec. 31, 2023 USD ($) Site |
Loss Contingencies [Line Items] | |
Number of identified MGP, landfill, or disposal sites under current investigation and/or remediation | Site | 1 |
Cost of identified MGP, landfill, or disposal sites under current investigation and/or remediation | $ | $ 13,000,000 |
Commitments and Contingencies E
Commitments and Contingencies Environmental Requirements - Water and Waste (Details) $ in Millions | Dec. 31, 2023 USD ($) |
Loss Contingencies [Line Items] | |
Number of sites required to comply with regulation | 2 |
Capital Addition Purchase Commitments [Member] | Federal Clean Water Act Section 316 (b) [Member] | |
Loss Contingencies [Line Items] | |
Liability for estimated cost to comply with regulation | $ 5 |
Commitments and Contingencies,
Commitments and Contingencies, Asset Retirement Obligations (Details) - USD ($) $ in Millions | 12 Months Ended | ||||
Dec. 31, 2023 | Dec. 31, 2022 | ||||
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] | |||||
Beginning balance | $ 28 | [1] | $ 26 | [2] | |
Accretion | [2] | 1 | |||
Cash Flow Revisions | (7) | [1],[3] | 1 | [2],[4] | |
Ending balance | [1] | 22 | 28 | ||
Steam, hydro and other production | |||||
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] | |||||
Beginning balance | 10 | 9 | |||
Accretion | 0 | 1 | |||
Cash Flow Revisions | (1) | [3] | 0 | [4] | |
Ending balance | 9 | 10 | |||
Electric Plant Electric Distribution | |||||
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] | |||||
Beginning balance | 5 | 5 | |||
Accretion | 0 | 0 | |||
Cash Flow Revisions | 0 | [3] | 0 | [4] | |
Ending balance | 5 | 5 | |||
Natural Gas Plant Gas Distribution | |||||
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] | |||||
Beginning balance | 13 | 12 | |||
Accretion | 1 | 0 | |||
Cash Flow Revisions | (6) | [3] | 1 | [4] | |
Ending balance | $ 8 | $ 13 | |||
[1] Included in other long-term liabilities balance in the consolidated balance sheet. Included in other long-term liabilities balance in the consolidated balance sheet. In 2023, AROs were revised for changes in timing and estimates of cash flows. Changes in gas distribution AROs were a result of updated mileage of gas lines and number of services, as well as changes to inflation and discount rate assumptions. In 2022, AROs were revised for changes in timing and estimates of cash flows. |
Indeterminate AROs (Details)
Indeterminate AROs (Details) $ in Millions | Dec. 31, 2023 USD ($) |
Asset Retirement Obligations [Line Items] | |
Indeterminate Costs Incurred, Asset Retirement Obligation Due to Asbestos | $ 0 |
Commitments and Contingencies_3
Commitments and Contingencies, Joint Operating System (Details) $ in Millions | 12 Months Ended |
Dec. 31, 2023 USD ($) Counterparty Reactor Plant | |
Joint Operating System [Abstract] | |
Number of companies covered by FERC approved Interchange Agreement | Counterparty | 2 |
NSP-Minnesota | Nuclear Insurance | |
Joint Operating System [Abstract] | |
Nuclear insurance coverage secured for the Company's public liability exposure | $ 450 |
Nuclear insurance coverage exposure funded by the Secondary Financial Protection Program | 15,800 |
Maximum assessments per reactor per accident | $ 166 |
Number of owned and licensed reactors | Reactor | 3 |
Maximum funding requirement per reactor for any one year | $ 24.7 |
Number of nuclear plant sites operated by NSP-Minnesota | Plant | 2 |
Maximum assessments for business interruption insurance each calendar year | $ 15 |
Maximum assessment for property damage insurance NSP-Minnesota is subject to each calendar year | 32 |
NSP-Minnesota | Maximum | Nuclear Insurance | |
Joint Operating System [Abstract] | |
Maximum possible loss contingency | 16,200 |
Insurance coverage limits for NSP-Minnesota's nuclear plant sites | 2,800 |
Business Interruption Insurance Coverage Provided by NEIL | 490 |
Business Interruption Insurance Coverage Provided by NEIL - Prairie Island | $ 420 |
Commitments and Contingencies_4
Commitments and Contingencies, Fuel Contracts (Details) $ in Millions | 12 Months Ended | |
Dec. 31, 2023 USD ($) | ||
Commitments and Contingencies Disclosure [Abstract] | ||
Minimum annual tolerance band percentage for future rate recovery or refund of fuel costs | 2% | |
Natural Gas Supply | ||
Fuel Contracts [Abstract] | ||
2024 | $ 9 | |
2025 | 0 | |
2026 | 0 | |
2027 | 0 | |
2028 | 0 | |
Thereafter | 0 | |
Total | 9 | [1] |
Natural Gas Storage and Transportation | ||
Fuel Contracts [Abstract] | ||
2024 | 21 | |
2025 | 19 | |
2026 | 19 | |
2027 | 13 | |
2028 | 3 | |
Thereafter | 8 | |
Total | 83 | [1] |
RDF/wood | ||
Fuel Contracts [Abstract] | ||
2024 | 6 | |
2025 | 1 | |
2026 | 1 | |
2027 | 0 | |
2028 | 1 | |
Thereafter | 1 | |
Total | $ 10 | [1] |
[1] Excludes additional amounts allocated to NSP-Minnesota through intercompany charges. |
Other Comprehensive Income (Det
Other Comprehensive Income (Details) $ in Millions | Dec. 31, 2023 USD ($) |
AOCI Attributable to Parent, Net of Tax [Roll Forward] | |
Accumulated other comprehensive loss at beginning of period | $ 1,259 |
Accumulated other comprehensive loss at end of period | $ 1,366 |
Other Comprehensive Income Othe
Other Comprehensive Income Other Comprehensive Income Phantom (Details) - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | |
Accumulated Other Comprehensive Income (Loss) [Line Items] | |||
Total income tax expense | $ 40 | $ 35 | $ 30 |
Segments and Related Informat_3
Segments and Related Information (Details) - USD ($) $ in Millions | 12 Months Ended | |||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | ||
Segment Reporting Information [Line Items] | ||||
Unregulated Operating Revenue | $ 1 | $ 1 | $ 1 | |
Regulated and Unregulated Operating Revenue | 1,177 | 1,201 | 1,105 | |
Depreciation and amortization | 170 | 158 | 147 | |
Interest charges and financing costs | 50 | 42 | 40 | |
Total income tax expense | 40 | 35 | 30 | |
Net income | 136 | 125 | 108 | |
Electric, affiliates | 204 | 202 | 189 | |
Natural gas | 157 | 198 | 182 | |
Regulated Electric | ||||
Segment Reporting Information [Line Items] | ||||
Revenues Including Intersegment Revenues | [1] | 1,019 | 1,002 | 922 |
Depreciation and amortization | 142 | 131 | 120 | |
Interest charges and financing costs | 45 | 38 | 36 | |
Total income tax expense | 38 | 29 | 27 | |
Net income | 126 | 105 | 98 | |
Regulated Natural Gas | ||||
Segment Reporting Information [Line Items] | ||||
Revenues Including Intersegment Revenues | 158 | 198 | 183 | |
Depreciation and amortization | 28 | 27 | 27 | |
Interest charges and financing costs | 5 | 4 | 4 | |
Total income tax expense | 2 | 6 | 2 | |
Net income | 9 | 17 | 7 | |
All Other | ||||
Segment Reporting Information [Line Items] | ||||
Total income tax expense | 0 | 0 | 1 | |
Net income | 1 | 3 | 3 | |
Total revenues | ||||
Segment Reporting Information [Line Items] | ||||
Regulated and Unregulated Operating Revenue | [1] | 1,178 | 1,201 | 1,106 |
Total revenues | Regulated Natural Gas | ||||
Segment Reporting Information [Line Items] | ||||
Natural gas | 157 | 198 | 182 | |
Total revenues | All Other | ||||
Segment Reporting Information [Line Items] | ||||
Unregulated Operating Revenue | 1 | 1 | 1 | |
Intersegment Eliminations | ||||
Segment Reporting Information [Line Items] | ||||
Regulated and Unregulated Operating Revenue | (1) | 0 | (1) | |
Intersegment Eliminations | Regulated Natural Gas | ||||
Segment Reporting Information [Line Items] | ||||
Natural gas | $ 1 | $ 0 | $ 1 | |
[1] Operating revenues include $204 million, $202 million and $189 million of affiliate electric revenue for the years ended Dec. 31, 2023, 2022 and 2021, respectively. See Note 12 for further information. |
Related Party Transactions (Det
Related Party Transactions (Details) - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | |
Operating expenses | |||
Other receivables | $ 0 | $ 19 | |
Accounts payable to affiliates | 21 | 19 | |
NSP-Minnesota | |||
Operating expenses | |||
Other receivables | 0 | 0 | |
Accounts payable to affiliates | 9 | 4 | |
PSCo | |||
Operating expenses | |||
Other receivables | 1 | 2 | |
Accounts payable to affiliates | 0 | 0 | |
Other subsidiaries of Xcel Energy Inc. | |||
Operating expenses | |||
Other receivables | 12 | 6 | |
Accounts payable to affiliates | 13 | 15 | |
Xcel Energy [Member] | |||
Operating expenses | |||
Other receivables | 13 | 8 | |
Accounts payable to affiliates | 22 | 19 | |
Purchased Power | |||
Operating expenses | |||
Costs and Expenses, Related Party | 424 | 445 | $ 408 |
Transmission Expense | |||
Operating expenses | |||
Costs and Expenses, Related Party | 69 | 68 | 64 |
Natural Gas Purchase for Resale | |||
Operating expenses | |||
Costs and Expenses, Related Party | 1 | 0 | 1 |
Other Expense | |||
Operating expenses | |||
Costs and Expenses, Related Party | 119 | 114 | 99 |
Interest Expense | |||
Operating expenses | |||
Costs and Expenses, Related Party | 1 | 1 | 0 |
Electricity, US Regulated | Xcel Energy [Member] | |||
Operating expenses | |||
Revenues | 204 | 202 | 189 |
Interest and Other Income | $ 1 | $ 0 | $ 0 |
Compensation Related Costs, P_2
Compensation Related Costs, Postemployment Benefits (Details) $ in Millions | 12 Months Ended |
Dec. 31, 2023 USD ($) Employees | |
Xcel Energy [Member] | |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | |
Other Postretirement Benefits Cost (Reversal of Cost) | $ | $ 72 |
NSP Wisconsin [Member] | |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | |
Other Postretirement Benefits Cost (Reversal of Cost) | $ | $ 5 |
Employee Severance | Xcel Energy [Member] | |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | |
Entity Number of Employees | Employees | 150 |
Voluntary Retirement Program | Xcel Energy [Member] | |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | |
Entity Number of Employees | Employees | 400 |
Schedule II, Valuation and Qu_2
Schedule II, Valuation and Qualifying Accounts (Details) - Allowance for Bad Debts - USD ($) $ in Millions | 12 Months Ended | |||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | ||
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] | ||||
Balance at Jan. 1 | $ 9 | $ 8 | $ 8 | |
Charged to costs and expenses | 4 | 4 | 4 | |
Charged to other accounts | [1] | 1 | 1 | 1 |
Deductions from reserves | [2] | (5) | (4) | (5) |
Balance at Dec. 31 | $ 9 | $ 9 | $ 8 | |
[1] Recovery of amounts previously written-off. Deductions related primarily to bad debt write-offs. |