3434.45251134.453634.4541071134.4551211.01848131234.45691434.4572101634.4581134.4591234.460135034.4611434.462153.117.134.46316213.217.234.4641734.46518522234.46619134.4672034.4682134.4692234.47023334.4714244true534.4722518634.4737262834.47432794334.4751028251134.4764295.112534.47713302061434.47831true1513234.47916321815182234.48015.13312034.48121342234.4823522237.0134.4832.0024367.02262.017.0334.48437282.027.0434.48529382.037.0634.38434.52034.31634.18014.001840.01109.140.017614.001940.011140.017734.5219.1134.31734.38534.18114.00209.1240.011240.017834.18234.5221634.31834.38614.00219.1314.002240.01131740.017934.5239.1434.31934.38734.18314.00239.1540.011440.018034.18434.52434.32034.38814.00249.1614.002540.011540.018134.52534.32134.38934.18514.002640.011640.018234.18634.526834.32234.39014.002723714.002840.011740.01832434.52734.32334.39134.18740.011840.018434.18834.52834.32434.39240.011940.018534.18934.52934.32534.39340.012040.018634.53034.32634.39434.19040.018734.19134.53134.32734.39514.004340.018834.53234.32834.39634.19214.0044140.018934.53314.004534.32934.39734.193214.004640.019034.53434.33034.39834.194314.02914.0047440.019134.19534.39914.03034.53514.004834.331714.03114.004940.019234.53634.33234.40034.196814.03214.0050940.019314.03334.53714.005134.33334.40134.19712414.03414.005240.019434.19834.53834.33434.40231314.03514.00531440.019534.19914.03634.54014.005434.33534.40351514.03714.005540.019634.200634.59834.33634.4041814.03814.0056191940.019714.008534.20114.03934.33734.40522014.008614.04140.0198334.33834.40634.2022314.008742440.019914.009234.33934.40734.20352514.009340.0200634.34034.40834.2042614.0094714.009534.34134.40934.205814.000114.0096914.000234.34234.41034.20614.00971014.000314.009834.34334.41134.20711114.00041214.0005234.34434.41234.2081314.00063Montana Operations34.34534.41334.2091414.000741514.0008534.34634.41434.2101614.0009634.34734.41534.2111714.001071814.0011834.34834.41634.2121914.0012934.34934.41734.2132014.00131014.002914.0069934.24834.1123114.0070641034.24934.11326.01351134.25034.11436.02166.031234.25134.1156176.04921334.25234.11686.053106.061434.25334.11740.008191146.071340.0082101534.25434.11856.081540.00836.091634.25534.1191666.101840.00841734.25634.1207740.00857.011834.25734.12187.0240.00861934.25834.122940.00872034.25934.1231040.00882134.26034.1241140.00892234.26134.1251240.00902334.26234.12613240.00912434.263434.127141540.00922534.26434.128156340.00932634.265734.1294168540.00942734.26634.130176840.00952834.26734.1317187840.00962934.26834.132199940.00973034.26934.133101020111140.00983234.27034.13422112140.00993334.27134.1352232340.01003434.27234.136234440.010134.00134.27334.1375245640.010234.00234.27434.1382540.010334.00334.27534.1392640.010434.00434.27634.1402714.01540.010534.00534.27734.1412814.01640.010634.00634.27834.14214.0172914.01840.010734.00734.27934.1433014.01940.010834.00834.28034.14414.0203114.02140.010934.00934.28134.1453214.02240.02142.0434.04440.002640.00683913.0840.013440.02152.0540.006940.013534.04540.0027402.0640.0216540.007040.01362.0734.04640.002840.021762.083440.007140.013734.047South Dakota Operations40.00292.0940.021840.007240.013840.00302.1034.04840.02192.1140.007340.013934.04940.00312.1240.022040.007440.014040.00322.1334.05040.02212.1440.007540.014134.05140.00332.1540.02223640.007640.01422.1634.05240.003440.02232.1740.007740.014334.05340.00352.1840.022440.007840.01442.1934.05440.0036false40.02252.2040.007940.014534.05540.00372.2140.022640.008040.01463.0034.05640.003840.02273.013840.014734.05740.00393.0240.022840.01483.0334.05840.004040.02293.0440.014934.059440.023040.015034.06040.023140.015134.06140.02324040.015234.06240.023340.015334.063C00178940.023440.015434.06440.023540.015534.06540.023640.015634.06640.02374240.015734.06740.023840.015834.068O40.0239146840.01597834.069677740.024040.016034.070798434.0719685441034.07271134.0731287715.0197934.07415.021034.07515.03Not Prepared34.07624634.077134.41834.486134.41934.4872334.42034.48824134.42134.4895334.42234.4904634.42334.49157634.42434.4927834.42534.49389934.42634.494101034.42734.49511111234.42834.4961234.42934.4971334.43034.4981434.43134.4991534.43234.50034.43334.50135.00134.43434.50235.00234.43534.50335.00334.43634.50435.03340.016134.43734.50540.016234.43834.50640.016334.43934.50740.016434.44034.50840.016534.44134.509840.016634.44234.51040.016734.44334.51140.016834.44434.51240.016934.44534.51340.017034.44634.5149.0140.01719.0234.44734.5159.0340.017234.44834.5169.04140.017334.4499.0534.517119.0640.0174234.45034.5189.07340.01759.0834.45134.51949.092114.0014134.35034.21414.0030214.003134.35134.21514.0032334.35234.21614.0033414.003434.35334.217614.003534.35434.218714.003614.0037834.35534.21914.0038934.35634.22014.00391014.004034.35734.2211114.00414451419234.35834.22214.00421234.35934.22313115389841434.36034.2241534.36134.2251634.362134.22617101.0134.36334.22718111.0234.36434.22819121.03131.042034.36534.229234.36634.2302.012134.36734.2312132034.36834.232422534.36934.2332362434.37034.234725834.37134.23526934.37234.236101134.37334.2371234.37434.238131434.37534.239153334.37634.24016343534.37734.24134.37834.24234.37934.2431.021.0134.38034.24434.38134.24534.38234.24614.001514.001634.38334.24714.00171134.28234.07834.1467.0814.02333127.0914.02434.28334.07934.14734137.114.0251434.28434.08034.1487.1114.02635157.1214.02734.28534.08134.149167.1314.0281734.28634.08234.1507.14187.1534.28734.08334.151197.1634.2882034.08434.1527.17217.1840.004114.007134.28934.08534.1532214.007240.00422634.29034.08634.15414.00732940.004314.007434.29134.08734.1553014.007540.00443234.29234.08834.15614.007640.004514.007734.29334.08934.15714.007840.004634.29434.09034.15814.007940.004714.008034.29534.09134.15914.008140.004834.29634.09234.16014.008240.004914.008334.29734.09334.16114.008440.005034.29834.09434.16240.005134.29934.09534.16340.005234.30034.09634.16440.005334.30134.09734.165240.0054101The Workiva Platform34.30234.09834.166340.005534.30334.09934.167440.0056534.30434.10034.168640.005734.30534.10134.169740.0058834.30634.10234.170940.00591234.30734.10334.1711040.006014.00571134.30834.10434.1722014.00581240.006134.17334.30934.1052014.00591340.006214.00601434.31034.10634.17414.006140.0063234.17534.31134.107314.006240.0064413.0114.006334.31234.10834.17613.0214.006440.006534.31313.0334.10934.17714.006540.006613.0414.006634.31434.11034.17813.0514.006740.006734.31513.0634.11134.17914.006813.0734.01034.0112434.012334.01334.01414.00140.024134.01540.0242134.01640.024325.1234.01725.2340.024414.002434.01814.003140.024514.004534.019440.000140.024614.005514.006634.02040.0002640.024714.00734.021740.00031040.024814.00881134.02240.000414.009940.024914.01034.0231040.000540.025014.0111114.009814.01234.02440.00061240.025114.009914.01334.0251340.00072614.010040.025214.0141414.010134.02640.000840.025314.010334.02740.0009440.0254334.02840.001040.025534.02940.001140.025634.03040.001227.240.025740.020134.03140.001340.012140.02022840.012234.03240.001440.020340.012334.03340.001540.0204111240.012434.03440.001640.020540.012534.03540.001740.020640.012634.03640.001840.02073040.012734.03740.0019140.0208240.012834.03840.0020340.020940.012934.03940.0021440.02101840.013034.0401940.0022540.021119.0140.013134.04140.0023619.0240.02123240.013234.04219.0340.0024740.021340.013334.04340.00258 C001789 Bridger Auto (BILLINGS), Transmission, Unattended 2023-12-31 C001789 ferc:LandAndRightsMember Missoula Miller Creek Sub site 2023-01-012023-12-31 C001789 ferc:PaidInCapitalMember Canadian Montana Pipeline Corporation - Paid in Capital 2022-12-31 C001789 Mill Creek Generating (BUTTE), Transmission, Unattended 2023-12-31 C001789 Bleau Lafave (VP Asset 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. NWMT GWA NF MONTANA OATT COLSTRIP GLWND1 2023-01-012023-12-31 C001789 Federal Unemplyment Tax, Unemployment Tax, Montana, 2022 2023-01-012023-12-31 C001789 Huron Gas Turbine Plant A (SD), Transmission, Unattended 2023-01-012023-12-31 C001789 ferc:PenaltyTaxMember 2022-12-31 C001789 Total South Dakota 2023-01-012023-12-31 C001789 ferc:LandAndRightsMember Billings Metra Sub Site 2023-12-31 C001789 Harlem (HAVRE), Transmission, Unattended 2023-01-012023-12-31 C001789 Avangrid Renewables, LLC , SF, Market-Based Rate 2023-01-012023-12-31 C001789 Projects & Studies Prepaid by Customers (Montana) 2022-12-31 C001789 Thompson Falls City (MISSOULA), Distribution, Unattended 2023-01-012023-12-31 C001789 ferc:ElectricUtilityMember 2022-01-012022-12-31 C001789 ferc:OtherTaxesAndFeesMemberferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 Vitol Inc. BPAT NWMT NF MONTANA OATT BPAT.NWMT MATL.NWMT 2023-01-012023-12-31 C001789 Aberdeen NE Gas Plant B (SD), Distribution, Unattended 2023-01-012023-12-31 C001789 First Mortgage Bonds 2.66% (South Dakota) 2023-12-31 C001789 Property Tax, Property Tax, North Dakota, 2022 2023-12-31 C001789 Miscellaneous 2023-01-012023-12-31 C001789 Annual Charges Under the Omnibus 2023-01-012023-12-31 C001789 Strawberry Creek (NON TIER II QF-1), LU, 2023-01-012023-12-31 C001789 ferc:MayMember South Dakota Operations 2023-01-012023-12-31 C001789 Other Debit or Cr. Items (Describe, details in footnote): 2023-01-012023-12-31 C001789 South Butte B (BUTTE), Transmission, Unattended 2023-01-012023-12-31 C001789 South Dakota Operations: 2023-01-012023-12-31 C001789 Lake 2023-01-012023-12-31 C001789 NorthWestern Energy Solutions, Inc. 2023-12-31 C001789 Morgan Stanley Capital Group, Inc. BPAT NWMT SFP MONTANA OATT BPAT.NWMT MATL.NWMT 2023-01-012023-12-31 C001789 Judith Gap Auto (BILLINGS), Transmission, Unattended 2023-01-012023-12-31 C001789 Basin Electric Power Cooperative NWMT WAUW NF MONTANA OATT MATL.NWMT GREATFALLS 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. PPW BPAT SFP MONTANA OATT BRDY BPAT.NWMT 2023-01-012023-12-31 C001789 Pension Requirement (South Dakota) 2023-12-31 C001789 Line Interconnection Studies 2023-01-012023-12-31 C001789 ferc:OtherTaxesAndFeesMember 2023-12-31 C001789 Interest Rate Hedge Amortizations 2023-01-012023-12-31 C001789 Excess Deferred Income Taxes (South Dakota) 2023-01-012023-12-31 C001789 Minor Projects (Less than $250,000 - 18 items) 2023-01-012023-12-31 C001789 Other Minor Items (4) - some are amortized over various periods (South Dakota) 2022-12-31 C001789 Anthony T. Clark 2023-01-012023-12-31 C001789 Whatley (HAVRE), Transmission, Unattended 2023-01-012023-12-31 C001789 MAG Energy Solutions NWMT PACE SFP MONTANA OATT MATL.NWMT BRDY 2023-01-012023-12-31 C001789 ferc:FederalInsuranceTaxMemberferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 Puget Sound Energy Marketing AVA MLCK NF MONTANA OATT COLSTRIP MLCK 2023-01-012023-12-31 C001789 Mitchell NW (SD), Transmission, Unattended 2023-12-31 C001789 ferc:OtherUtilityOrNonutilityMember Other - 30% 2023-01-012023-12-31 C001789 Excess Deferred Income Taxes (Montana) 2023-01-012023-12-31 C001789 EELT Tax, Other Taxes, Montana, 2022 2023-01-012023-12-31 C001789 Portland General Electric Company BPAT NWMT NF MONTANA OATT BPAT.NWMT NWMT.SYSTEM 2023-01-012023-12-31 C001789 Shell Energy North America BPAT PPW NF MONTANA OATT BPAT.NWMT YTP 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. NWMT PACE SFP MONTANA OATT MATL.NWMT BRDY 2023-01-012023-12-31 C001789 First Mortgage Bonds 4.03% (Montana) 2023-01-012023-12-31 C001789 Sun River Elect Coop OLF 2023-01-012023-12-31 C001789 First Mortgage Bonds 3.99% (Montana) 2023-01-012023-12-31 C001789 Common Stock Dividend 2023-01-012023-12-31 C001789 Basin Creek Capital Lease (Montana) 2022-12-31 C001789 CP Energy Marketing (US) Inc. BPAT NWMT NF MONTANA OATT BPAT.NWMT MATL.NWMT 2023-01-012023-12-31 C001789 Aberdeen Ethanol (SD), Distribution, Unattended 2023-01-012023-12-31 C001789 The Energy Authority BPAT NWMT NF MONTANA OATT BPAT.NWMT MATL.NWMT 2023-01-012023-12-31 C001789 Yankton City (SD), Distribution, Unattended 2023-01-012023-12-31 C001789 Macquarie Energy, LLC PPW BPAT SFP MONTANA OATT YTP BPAT.NWMT 2023-01-012023-12-31 C001789 ferc:ElectricUtilityMember 2023-12-31 C001789 500 kV Operations - Partner's Share (Montana) 2022-12-31 C001789 Shell Energy North America BPAT NWMT NF MONTANA OATT BPAT.NWMT NWMT.SYSTEM 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. NWMT BPAT NF MONTANA OATT JUDITHGAP BPAT.NWMT 2023-01-012023-12-31 C001789 Kent T. Larson 2023-01-012023-12-31 C001789 Kershaw Switchyard (GREAT FALLS), Transmission, Unattended 2023-12-31 C001789 West Central Elect COOP FNS 2023-01-012023-12-31 C001789 Total Yellowstone Park 2023-01-012023-12-31 C001789 ferc:GasUtilityMember Unbilled Revenue 2022-12-31 C001789 Altop Energy Trading LLC PPW WAPA NF MONTANA OATT BRDY CROSSOVER 2023-01-012023-12-31 C001789 Montana Operationsferc:AugustMember 2023-01-012023-12-31 C001789 Tripp Jct. (SD), Transmission, Unattended 2023-12-31 C001789 ferc:OtherTaxesAndFeesMember 2022-12-31 C001789 Energy Keepers Inc. NWMT BPAT NF MONTANA OATT MATL.NWMT BPAT.NWMT 2023-01-012023-12-31 C001789 Huron Gas Turbnie Plant B (SD), Transmission, Unattended 2023-01-012023-12-31 C001789 First Mortgage Bonds 4.30% (Montana) 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. GWA AVA SFP MONTANA OATT GLWND1 AVAT.NWMT 2023-01-012023-12-31 C001789 South Peak Wind (NON TIER II QF-1), LU, 2023-01-012023-12-31 C001789 Generating Stations Under Project License 2023-01-012023-12-31 C001789 Landers Fork (HELENA), Distribution, Unattended 2023-01-012023-12-31 C001789 Rainbow Electric Marketing Corp. PACE NWMT NF MONTANA OATT YTP MATL.NWMT 2023-01-012023-12-31 C001789 All 69 kV, , Various, 2023-01-012023-12-31 C001789 ferc:IncomeTaxMember 2023-01-012023-12-31 C001789 Shell Energy North America BPAT WAPA SFP MONTANA OATT BPAT.NWMT CROSSOVER 2023-01-012023-12-31 C001789 MT Residential 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. WAUW NWMT NF MONTANA OATT CROSSOVER MATL.NWMT 2023-01-012023-12-31 C001789 ferc:SulfurDioxideMemberferc:ThreeYearsMember 2023-12-31 C001789 Oak Tree (PPA Wind #2) (SOUTH DAKOTA PURCHASES), LU, 2023-01-012023-12-31 C001789 MT Irrigation 2023-01-012023-12-31 C001789 ferc:SulfurDioxideMember 2023-12-31 C001789 Platte A (SD), Distribution, Unattended 2023-12-31 C001789 Gross Receipts Tax, Other Taxes, South Dakota, 2023 2023-12-31 C001789 MAG Energy Solutions WAPA PPW NF MONTANA OATT CROSSOVER BRDY 2023-01-012023-12-31 C001789 Johnson Lane (BILLINGS), Distribution, Unattended 2023-01-012023-12-31 C001789 Projects & Studies Prepaid by Customers (Montana) 2023-01-012023-12-31 C001789 Stickney Jct. (SD), Transmission, Unattended 2023-01-012023-12-31 C001789 ferc:GasUtilityMember Pension/Postretirement Benefits 2023-12-31 C001789 ferc:OtherAllocatedTaxMember 2023-01-012023-12-31 C001789 Colstrip City (BILLINGS), Transmission, Unattended 2023-01-012023-12-31 C001789 Guzman Energy, LLC WAPA PPW NF MONTANA OATT CROSSOVER YTP 2023-01-012023-12-31 C001789 Puget Sound Energy Marketing BPAT NWMT NF MONTANA OATT BPAT.NWMT COLSTRIP 2023-01-012023-12-31 C001789 California Independent System Operator - EIM Transmission (PURCHASED POWER SUPPLY), SF, CAISO 2023-01-012023-12-31 C001789 Hanover Hydro (NON TIER II QF-1), LU, 2023-01-012023-12-31 C001789 ferc:IncomeTaxMember 2023-12-31 C001789 PacifiCorp PPW NWMT SFP MONTANA OATT MLCK JEFF 2023-01-012023-12-31 C001789 Redfield D (SD), Transmission, Unattended 2023-01-012023-12-31 C001789 2023-01-012023-09-30 C001789 Great Falls Northeast (GREAT FALLS), Distribution, Unattended 2023-01-012023-12-31 C001789 ferc:OtherLicenseAndFeesTaxMember 2023-12-31 C001789 ferc:OtherStateTaxMember 2022-12-31 C001789 Richardson Coulee (HAVRE), Transmission, Unattended 2023-01-012023-12-31 C001789 SociVolta, Inc. PACE NWMT NF MONTANA OATT BRDY MATL.NWMT 2023-01-012023-12-31 C001789 First Mortgage Bonds 4.15% (South Dakota) 2023-12-31 C001789 ferc:ExciseTaxMember 2022-12-31 C001789 The Energy Authority AVA PPW NF MONTANA OATT AVAT.NWMT BRDY 2023-01-012023-12-31 C001789 First Mortgage Bonds 4.03% (Montana) 2023-12-31 C001789 ScheduleTransmissionLinesAddedAbstract 2023-01-012023-12-31 C001789 Basin Electric Power Cooperative Basin Electric & WAPA Basin Electric Power Cooperative FNO Montana OATT BPAT.NWMT & Great Falls Various NWMT & WAUW 2023-01-012023-12-31 C001789 ferc:GasUtilityMember 2023-12-31 C001789 Treasury Stock Activity 2023-01-012023-12-31 C001789 Puget Sound Energy Marketing NWMT BPAT SFP MONTANA OATT COLSTRIP BPAT.NWMT 2023-01-012023-12-31 C001789 ferc:GasUtilityMember Compensation Accruals 2022-12-31 C001789 Dynasty Power Inc. PPW BPAT NF MONTANA OATT YTP BPAT.NWMT 2023-01-012023-12-31 C001789 Butte Cora (BUTTE), Distribution, Unattended 2023-12-31 C001789 Big Stone Plant A (SD), Transmission, Unattended 2023-01-012023-12-31 C001789 Aberdeen Industrial Park (SD), Distribution, Unattended 2023-12-31 C001789 FERC Order No. 472 2023-01-012023-12-31 C001789 Basin Electric Power Cooperative PPW WAPA SFP MONTANA OATT YTP CROSSOVER 2023-01-012023-12-31 C001789 Canadian Montana Pipeline Corporation - Translation Adjustmentferc:OtherInvestmentsInSubsidiaryCompaniesMember 2022-12-31 C001789 Risk Partners Assurance, Ltd. 2023-01-012023-12-31 C001789 Permanent Uncertain Tax Positions (Montana) 2023-01-012023-12-31 C001789 Energy Keepers, Inc. (PURCHASED POWER SUPPLY), SF, Market-Based Rate Tariff 2023-01-012023-12-31 C001789 Heavy Highway Tax, Other Taxes, South Dakota, 2023ferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. GWA PPW NF MONTANA OATT GLWND1 BRDY 2023-01-012023-12-31 C001789 Meridian (BILLINGS), Distribution, Unattended 2023-12-31 C001789 Oil DGGS 2023-01-012023-12-31 C001789 Big Sky Midway B (BOZEMAN), Distribution, Unattended 2023-12-31 C001789 Two Dot 2023-01-012023-12-31 C001789 Redfield C (SD), Transmission, Unattended 2023-12-31 C001789 Transmission Line Rights (Montana) 2023-01-012023-12-31 C001789 ferc:NitrogenOxideMember Allowances Used 2023-01-012023-12-31 C001789 Federal Income Tax, Income Tax, Montana, 2023 2023-12-31 C001789 Big Timber Auto (BOZEMAN), Transmission, Unattended 2023-12-31 C001789 ferc:OtherUseTaxMember 2023-01-012023-12-31 C001789 Excess Tax Depreciation 2023-01-012023-12-31 C001789 Constellation Energy Generation, LLC , SF, Market-Based Rate 2023-01-012023-12-31 C001789 Mobile 8 2023-01-012023-12-31 C001789 Dynasty Power, Inc. (PURCHASED POWER SUPPLY), SF, Market-Based Rate Tariff 2023-01-012023-12-31 C001789 Southwest Power Pool (MT) FNS 2023-01-012023-12-31 C001789 Basin Creek Capital Lease (Montana) 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. GWA BPAT NF MONTANA OATT GLWND2 BPAT.NWMT 2023-01-012023-12-31 C001789 Aberdeen 8th Avenue (SD), Distribution, Unattended 2023-01-012023-12-31 C001789 Billings Eighth Street (BILLINGS), Transmission, Unattended 2023-12-31 C001789 Heavy Highway Tax, Other Taxes, Montana, 2023 2023-12-31 C001789 Huron City A (SD), Distribution, Unattended 2023-01-012023-12-31 C001789 Guzman Energy, LLC  (PURCHASED POWER SUPPLY), SF, Market-Based Rate Tariff 2023-01-012023-12-31 C001789 Great Falls Public Schools Energy Keepers Inc. Great Falls Public Schools FNO Montana OATT Kerr Great Falls, MT 2023-01-012023-12-31 C001789 Transalta Energy Marketing (US) Inc. 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BPAT WAPA NF MONTANA OATT BPAT.NWMT CROSSOVER 2023-01-012023-12-31 C001789 Personal Property - Auto, Other Taxes, Montana, 2023ferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 Dynasty Power Inc. PPW NWMT NF MONTANA OATT BRDY GTFALLSNWMT 2023-01-012023-12-31 C001789 Naturener Power Watch, LLC GWA GWA SFP MONTANA OATT GLWND1 GLWND2 2023-01-012023-12-31 C001789 Unamortized Debt Expense (South Dakota) 2022-12-31 C001789 First Mortgage Bonds 5.01% (South Dakota) 2023-12-31 C001789 7% 2023-01-012023-12-31 C001789 FEA Studies 2023-01-012023-12-31 C001789 Oil Big Stone 2023-01-012023-12-31 C001789 Drummond City (BUTTE), Transmission, Unattended 2023-01-012023-12-31 C001789 Mobile 3 2023-12-31 C001789 Macquarie Energy, LLC PPW BPAT NF MONTANA OATT BRDY BPAT.NWMT 2023-01-012023-12-31 C001789 Shell Energy North America NWMT WAUW NF MONTANA OATT BGI GREATFALLS 2023-01-012023-12-31 C001789 WAPA Broadland (SD), Transmission, Unattended 2023-12-31 C001789 Macquarie Energy, LLC NWMT NWMT SFP MONTANA OATT TFALLS NWMT.SYSTEM 2023-01-012023-12-31 C001789 Asset Retirement Obligation (Montana) 2023-01-012023-12-31 C001789 Judith Gap South (BILLINGS), Transmission, Unattended 2023-01-012023-12-31 C001789 Administration Fee, Havre Pipeline Company, LLC 2023-01-012023-12-31 C001789 Great Falls Southside (GREAT FALLS), Distribution, Unattended 2023-01-012023-12-31 C001789 TEC Energy Inc. PACE NWMT NF MONTANA OATT YTP MATL.NWMT 2023-01-012023-12-31 C001789 Aberdeen Fairgrounds (SD), Distribution, Unattended 2023-01-012023-12-31 C001789 Rainbow Electric Marketing Corp. WAUW NWMT NF MONTANA OATT CROSSOVER MATL.NWMT 2023-01-012023-12-31 C001789 Huron West Park B (SD), Transmission, Unattended 2023-01-012023-12-31 C001789 MAG Energy Solutions PACE NWMT NF MONTANA OATT BRDY MATL.NWMT 2023-01-012023-12-31 C001789 Other Minor Items (4) - some are amortized over various periods (South Dakota) 2023-01-012023-12-31 C001789 Macquarie Energy, LLC PPW BPAT SFP MONTANA OATT BRDY BPAT.NWMT 2023-01-012023-12-31 C001789 EDF Trading North America, LLC NWMT BPAT NF MONTANA OATT COLSTRIP BPAT.NWMT 2023-01-012023-12-31 C001789 Shell Energy North America BPAT PPW NF MONTANA OATT BPAT.NWMT BRDY 2023-01-012023-12-31 C001789 Transalta Energy Marketing (US) Inc. WAPA PPW SFP MONTANA OATT CROSSOVER YTP 2023-01-012023-12-31 C001789 Highmore ER Interconnect (SD), Transmission, Unattended 2023-01-012023-12-31 C001789 Belgrade West (BOZEMAN), Transmission, Unattended 2023-12-31 C001789 First Mortgage Bonds 4.85% (South Dakota) 2023-01-012023-12-31 C001789 Lake 2023-12-31 C001789 Malta Auto (HAVRE), Transmission, Unattended 2023-01-012023-12-31 C001789 Mill Creek A (BUTTE), Transmission, Unattended 2023-01-012023-12-31 C001789 Huron Gas Turbnie Plant B (SD), Transmission, Unattended 2023-12-31 C001789 ferc:OtherFederalTaxMember 2023-01-012023-12-31 C001789 General Mills Operations, LLC Talen Energy General Mills Operations, LLC FNO Montana OATT Colstrip Great Falls, MT 2023-01-012023-12-31 C001789 QUALIFYING FACILITIES, , 2023-01-012023-12-31 C001789 ferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 ferc:ElectricUtilityMemberferc:GeneralPlantMember 2023-01-012023-12-31 C001789 Federal Income Tax, Income Tax, Montana, 2023 2022-12-31 C001789 Powerex Corporation BPAT AVA NF MONTANA OATT BPAT.NWMT AVAT.NWMT 2023-01-012023-12-31 C001789 Townsend (HELENA), Distribution, Unattended 2023-12-31 C001789 Morgan Stanley Capital Group, Inc. 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NWMT NWMT NF MONTANA OATT COLSTRIP NWMT.SYSTEM 2023-01-012023-12-31 C001789 Phillips 66 Energy Trading, LLC NWMT AVA SFP MONTANA OATT COLSTRIP AVAT.NWMT 2023-01-012023-12-31 C001789 Montana State University - Bozeman WAPA Montana State University - Bozeman FNO Montana OATT Fort Peck West Great Falls, MT 2023-01-012023-12-31 C001789 ferc:OtherFederalTaxMember 2022-12-31 C001789 Morgan Stanley Capital Group, Inc. WAPA AVA NF MONTANA OATT GREATFALLS AVAT.NWMT 2023-01-012023-12-31 C001789 Belgrade West (BOZEMAN), Transmission, Unattended 2023-01-012023-12-31 C001789 Dynasty Power Inc. 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BPAT NWMT NF MONTANA OATT BPAT.NWMT MATL.NWMT 2023-01-012023-12-31 C001789 Aspen Air U.S., LLC Talen Energy Aspen Air Corporation FNO Montana OATT Colstrip  Billings, MT 2023-01-012023-12-31 C001789 ferc:LandAndRightsMember Missoula Miller Creek Sub site 2023-12-31 C001789 (Less) (449.1) Provision for Rate Refunds 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. 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AVA NWMT NF MONTANA OATT AVAT.NWMT MATL.NWMT 2023-01-012023-12-31 C001789 Basin Electric Power Cooperative PPW PPW NF MONTANA OATT BRDY MLCK 2023-01-012023-12-31 C001789 Rainbow Electric Marketing Corp. PPW WAPA SFP MONTANA OATT YTP CROSSOVER 2023-01-012023-12-31 C001789 First Mortgage Bonds 5.71% (Montana) 2023-12-31 C001789 Consumer Counsel, Other Taxes, Montana, 2023 2023-12-31 C001789 Guzman Energy, LLC WAPA NWMT NF MONTANA OATT GREATFALLS NWMT.SYSTEM 2023-01-012023-12-31 C001789 Pension Plan (South Dakota) 2022-12-31 C001789 Property Tax, Property Tax, Iowa, 2023 2023-01-012023-12-31 C001789 Billings Conoco (BILLINGS), Distribution, Unattended 2023-12-31 C001789 Morgan Stanley Capital Group, Inc. 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BPAT PPW NF MONTANA OATT BPAT.NWMT BRDY 2023-01-012023-12-31 C001789 Transalta Energy Marketing (US) Inc. PPW PPW NF MONTANA OATT YTP ANTE 2023-01-012023-12-31 C001789 Billings Steam Plant Switchyard A (BILLINGS), Distribution, Unattended 2023-01-012023-12-31 C001789 Glengarry (BILLINGS), Transmission, Unattended 2023-12-31 C001789 Rainbow Energy Marketing Corporation (PURCHASED POWER SUPPLY), SF, Market-Based Rate Tariff 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. 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Horsfall 2023-01-012023-12-31 C001789 FICA and Medicare, Federal Tax, South Dakota, 2023 2023-12-31 C001789 BONNEVILLE POWER ADMINISTRATION, LF, Reserve Energy 2023-01-012023-12-31 C001789 Dillon City (BUTTE), Distribution, Unattended 2023-12-31 C001789 Morgan Stanley Capital Group, Inc. GWA PPW NF MONTANA OATT GLWND2 BRDY 2023-01-012023-12-31 C001789 Ashgrove Transformer Upgrade 2023-01-012023-12-31 C001789 SD 25 Comm Heating 2023-01-012023-12-31 C001789 NorthWestern Energy Solutions, Inc. 2023-01-012023-12-31 C001789 Transalta Energy Marketing (US) Inc. PPW BPAT NF MONTANA OATT YTP BPAT.NWMT 2023-01-012023-12-31 C001789 Three Forks South (BOZEMAN), Distribution, Unattended 2023-01-012023-12-31 C001789 Property Tax, Property Tax, Nebraska, 2022 2022-12-31 C001789 GRANT COUNTY PUD, LF, Reserve Energy 2023-01-012023-12-31 C001789 Ennis City (BOZEMAN), Distribution, Unattended 2023-12-31 C001789 Johnson Lane Bank 1ferc:ElectricUtilityMember 2023-12-31 C001789 Billings Rimrock Auto A (BILLINGS), Transmission, Unattended 2023-12-31 C001789 Neal 2023-12-31 C001789 Other Minor Items (7) - some are amortized over various periods  (Montana) 2022-12-31 C001789 The Energy Authority PPW WAPA SFP MONTANA OATT YTP CROSSOVER 2023-01-012023-12-31 C001789 Tripp Jct. (SD), Transmission, Unattended 2023-01-012023-12-31 C001789 Montana OATT, Attachment O, Formula Rate Protocols and Template, ER21-779-000 2023-01-012023-12-31 C001789 ferc:PropertyTaxMemberferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 EXCHANGES:, , 2023-01-012023-12-31 C001789 Redfield A (SD), Transmission, Unattended 2023-01-012023-12-31 C001789 Holter Wolf Creek (HELENA), Transmission, Unattended 2023-01-012023-12-31 C001789 ferc:ElectricUtilityMemberferc:DistributionPlantMember 2023-01-012023-12-31 C001789 Market Monitoring & Compliance 2023-01-012023-12-31 C001789 ScheduleResearchDevelopmentOrDemonstrationExpendituresAbstract 2023-01-012023-12-31 C001789 ferc:OtherElectricUtilityMember 2022-12-31 C001789 Morgan Stanley Capital Group, Inc. AVA BPAT NF MONTANA OATT AVAT.NWMT BPAT.NWMT 2023-01-012023-12-31 C001789 Western Area Power Administration WAPA PPW NF MONTANA OATT GREATFALLS YTP 2023-01-012023-12-31 C001789 ferc:ElectricPlantInServiceMemberferc:ElectricUtilityMember 2023-12-31 C001789 2188, Holter 2023-01-012023-12-31 C001789 Harlowtown B (BILLINGS), Transmission, Unattended 2023-01-012023-12-31 C001789 Precipitator (BUTTE), Distribution, Unattended 2023-12-31 C001789 Missoula Reserve Street (MISSOULA), Distribution, Unattended 2023-01-012023-12-31 C001789 Use Tax, Sales And Use Tax, Wyoming, 2023 2023-12-31 C001789 Montana Wildfire Mitigation 2023-01-012023-12-31 C001789 Macquarie Energy, LLC NWMT BPAT NF MONTANA OATT TFALLS BPAT.NWMT 2023-01-012023-12-31 C001789 Sibanye-Stillwater Various Stillwater Mining Company FNO Montana OATT As Available Various in Montana 2023-01-012023-12-31 C001789 Transfersferc:ElectricPlantInServiceMemberferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 Transalta Energy Marketing (US) Inc. NWMT AVA NF MONTANA OATT MATL.NWMT AVAT.NWMT 2023-01-012023-12-31 C001789 Billings Central (BILLINGS), Transmission, Unattended 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. NWMT NWMT SFP MONTANA OATT CROOKEDFALLS MATL.NWMT 2023-01-012023-12-31 C001789 , , 2023-01-012023-12-31 C001789 ferc:ElectricUtilityMember Ashgrove Transformer Upgrade 2023-01-012023-12-31 C001789 2023-01-012023-12-31 C001789 Miller Crk Rebuildferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 Flow-through Income Taxes (South Dakota) 2023-01-012023-12-31 C001789 Ohlman Substation (SD), Distribution, Unattended 2023-01-012023-12-31 C001789 Aberdeen Siebrecht C (SD), Transmission, Unattended 2023-12-31 C001789 Puget Sound Energy Marketing PPW PPW NF MONTANA OATT MLCK BRDY 2023-01-012023-12-31 C001789 ferc:Quarter3Member South Dakota Operations 2023-01-012023-12-31 C001789 Portland General Electric Company NWMT PPW NF MONTANA OATT COLSTRIP YTP 2023-01-012023-12-31 C001789 Golden Sunlight (BUTTE), Distribution, Unattended 2023-12-31 C001789 Livingston Westside B (BOZEMAN), Distribution, Unattended 2023-12-31 C001789 3% 2023-01-012023-12-31 C001789 Curt Pohl , Vice President, Asset Management & Business Development 2023-01-012023-12-31 C001789 Gross Receipts Tax, Other Taxes, South Dakota, 2023ferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 The Energy Authority WAPA NWMT NF MONTANA OATT CROSSOVER NWMT.SYSTEM 2023-01-012023-12-31 C001789 Highmore Plant A (SD), Transmission, Unattended 2023-12-31 C001789 ferc:SeveranceTaxMember 2023-12-31 C001789 Deferred Compensation (Montana) 2023-12-31 C001789 Portland General Electric Company NWMT AVA NF MONTANA OATT COLSTRIP AVAT.NWMT 2023-01-012023-12-31 C001789 Avista Corporation NWMT BPAT NF MONTANA OATT NWMTIMBALANC BPAT.NWMT 2023-01-012023-12-31 C001789 EELT Tax, Other Taxes, Montana, 2022 2022-12-31 C001789 Transalta Energy Marketing (US) Inc. BPAT PPW NF MONTANA OATT BPAT.NWMT BRDY 2023-01-012023-12-31 C001789 Unamortized Debt Expense (South Dakota) 2023-12-31 C001789 Missoula Reserve Street (MISSOULA), Transmission, Unattended 2023-12-31 C001789 Debt Financing Costs 2023-01-012023-12-31 C001789 CROOKED FALLS-GREAT FALLS ESferc:ElectricUtilityMember 2023-12-31 C001789 First Mortgage Bonds 4.30% (Montana) 2023-12-31 C001789 WMU West Sub (SD), Transmission, Unattended 2023-12-31 C001789 Property Tax, Property Tax, South Dakota, 2022 2023-01-012023-12-31 C001789 Canadian Montana Pipeline Corporation 2023-01-012023-12-31 C001789 ferc:OtherUseTaxMember 2023-12-31 C001789 ferc:FederalInsuranceTaxMember 2023-12-31 C001789 Morgan Stanley Capital Group, Inc. BPAT NWMT NF MONTANA OATT BPAT.NWMT NWMT.SYSTEM 2023-01-012023-12-31 C001789 Mitchell Bridle Acres (SD), Distribution, Unattended 2023-12-31 C001789 Deer Lodge City (BUTTE), Distribution, Unattended 2023-12-31 C001789 Energy Keepers Inc. AVA PPW NF MONTANA OATT AVAT.NWMT ANTE 2023-01-012023-12-31 C001789 Cham. Missouri View (SD), Distribution, Unattended 2023-01-012023-12-31 C001789 Missoula City Sub #1 (MISSOULA), Distribution, Unattended 2023-01-012023-12-31 C001789 Montana Public Service Commission Consumer Counsel Taxes (Montana) - Dockets 2017.9.78 and 2018.10.67 2023-01-012023-12-31 C001789 TOTAL      2023-01-012023-12-31 C001789 Musselshell Wind 1 (NON TIER II QF-1), LU, 2023-01-012023-12-31 C001789 Shell Energy North America AVA NWMT NF MONTANA OATT AVAT.NWMT NWMT.SYSTEM 2023-01-012023-12-31 C001789 Mitchell S. Edgerton (SD), Distribution, Unattended 2023-01-012023-12-31 C001789 Pension Plan Requirement (Montana) 2023-12-31 C001789 Heavy Highway Tax, Other Taxes, South Dakota, 2023 2023-01-012023-12-31 C001789 Boulder Auto (HELENA), Transmission, Unattended 2023-01-012023-12-31 C001789 Canadian-Montana Pipe Line Corporation 2023-12-31 C001789 Livingston Westside C (BOZEMAN), Distribution, Unattended 2023-01-012023-12-31 C001789 NorthWestern Energy Public Services Corporation 2023-01-012023-12-31 C001789 Bob Glanzer Gas 2023-01-012023-12-31 C001789 EDF Trading North America, LLC PPW NWMT NF MONTANA OATT BRDY GTFALLSNWMT 2023-01-012023-12-31 C001789 Federal Unemplyment Tax, Unemployment Tax, Montana, 2023 2023-12-31 C001789 Other Accounts (Specify, details in footnote): 2023-01-012023-12-31 C001789 Great Falls 230Kv - EASTSIDEferc:ElectricUtilityMember 2023-12-31 C001789 Hardin Auto A (BILLINGS), Transmission, Unattended 2023-01-012023-12-31 C001789 Holter U2 Generator Rewind 2023-01-012023-12-31 C001789 Renova Auto (BUTTE), Transmission, Unattended 2023-12-31 C001789 Mahvash Yazdi 2023-01-012023-12-31 C001789 ferc:OtherUtilityOrNonutilityMember OTHER TOTAL 2022-12-31 C001789 Western Area Power Administration PPW WAPA SFP MONTANA OATT YTP GREATFALLS 2023-01-012023-12-31 C001789 Yankton Sacred Heart (SD), Distribution, Unattended 2023-12-31 C001789 Morgan Stanley Capital Group, Inc. WAPA PPW NF MONTANA OATT GREATFALLS BRDY 2023-01-012023-12-31 C001789 Groton Basin Operated (SD), Transmission, Unattended 2023-01-012023-12-31 C001789 Market Monitoring & Compliance 2023-01-012023-03-31 C001789 Missoula Miller Creek A (MISSOULA), Transmission, Unattended 2023-12-31 C001789 Use Tax, Sales And Use Tax, South Dakota, 2023 2023-12-31 C001789 Mercuria Energy America, LLC PPW WAPA NF MONTANA OATT BRDY CROSSOVER 2023-01-012023-12-31 C001789 ferc:OperatingReserveSupplementMember 2023-01-012023-12-31 C001789 Gross Receipts Tax, Other Taxes, South Dakota, 2022 2023-12-31 C001789 Great Divide Solar LLC (NON TIER II SOLAR QF), LU, 2023-01-012023-12-31 C001789 IDAHO POWER COMPANY, LF, Reserve Energy 2023-01-012023-12-31 C001789 Great Falls Eastside (GREAT FALLS), Distribution, Unattended 2023-12-31 C001789 Lake Helena (HELENA), Transmission, Unattended 2023-01-012023-12-31 C001789 ferc:ElectricUtilityMember Federal Income Tax, Income Tax, South Dakota/Nebraska, 2023 2023-01-012023-12-31 C001789 ferc:ElectricUtilityMember Unbilled Revenue 2023-12-31 C001789 Mobile 2 2023-01-012023-12-31 C001789 Huron City B (SD), Distribution, Unattended 2023-01-012023-12-31 C001789 Livingston Northside (BOZEMAN), Distribution, Unattended 2023-01-012023-12-31 C001789 Powerex Corporation NWMT PACE NF MONTANA OATT MATL.NWMT BRDY 2023-01-012023-12-31 C001789 Missoula Industrial Sub (MISSOULA), Distribution, Unattended 2023-12-31 C001789 Other 2022-01-012022-12-31 C001789 Other Miscellaneous 2023-01-012023-12-31 C001789 2022-01-012022-12-31 C001789 South Dakota Detail Footnote 2023-01-012023-12-31 C001789 Columbus East (BILLINGS), Distribution, Unattended 2023-01-012023-12-31 C001789 NorthWestern Energy Solutions - Capital Stockferc:CaptialStockMember 2022-12-31 C001789 Basin Electric Power Cooperative PPW WAPA NF MONTANA OATT YTP GREATFALLS 2023-01-012023-12-31 C001789 MT Lighting 2023-01-012023-12-31 C001789 Macquarie Energy, LLC NWMT BPA NF MONTANA OATT BGI BPAT.NWMT 2023-01-012023-12-31 C001789 Amortization of 2022-01-012022-12-31 C001789 Portland General Electric Company PPW BPAT NF MONTANA OATT BRDY BPAT.NWMT 2023-01-012023-12-31 C001789 First Mortgage Bonds 3.98% (Montana) A 2023-12-31 C001789 Energy Keepers Inc. NWMT BPAT SFP MONTANA OATT COLSTRIP BPAT.NWMT 2023-01-012023-12-31 C001789 Mitchell Jr. High A (SD), Distribution, Unattended 2023-01-012023-12-31 C001789 Montana Public Service Commission, Other Taxes, Montana, 2023 2023-01-012023-12-31 C001789 Dynasty Power, Inc.  , SF, Market-Based Rate 2023-01-012023-12-31 C001789 Idaho Power Company AVA PPW NF MONTANA OATT AVAT.NWMT MLCK 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. NWMT BPAT SFP MONTANA OATT MATL.NWMT BPAT.NWMT 2023-01-012023-12-31 C001789 TALEN MONTANA, LLC, LF, Reserve Energy 2023-01-012023-12-31 C001789 PUGET SOUND ENERGY (RESERVE SHARING), LF, Reserve Energy Services 2023-01-012023-12-31 C001789 Missoula Russell Street (MISSOULA), Distribution, Unattended 2023-01-012023-12-31 C001789 Transalta Energy Marketing (US) Inc. BPAT PPW NF MONTANA OATT BPAT.NWMT JEFF 2023-01-012023-12-31 C001789 500 kV Operations - Partner's Share (Montana) 2023-12-31 C001789 Rainbow Electric Marketing Corp. PPW WAPA NF MONTANA OATT BRDY CROSSOVER 2023-01-012023-12-31 C001789 Alkali Creek (BILLINGS), Transmission, Unattended 2023-12-31 C001789 Landers Fork (HELENA), Distribution, Unattended 2023-12-31 C001789 Hydro Invasive Species Tax, Other Taxes, Montana, 2022 2022-12-31 C001789 Projects & Studies Prepaid by Customer (South Dakota) 2023-01-012023-12-31 C001789 Clatskanie Peoples Utility District - Electric (PURCHASED POWER SUPPLY), SF, Market-Based Rate Tariff 2023-01-012023-12-31 C001789 Minor Projects (Less than $250,000 - 18 items)ferc:LandAndRightsMember 2023-01-012023-12-31 C001789 Gross Receipts Tax, Other Taxes, South Dakota, 2022 2023-01-012023-12-31 C001789 Family Protector Plan Future Payments (South Dakota) 2023-01-012023-12-31 C001789 Powerex Corporation NWMT BPAT NF MONTANA OATT MATL.NWMT BPAT.NWMT 2023-01-012023-12-31 C001789 NorthWestern Energy Solutions - Equity in Undistributed Earningsferc:UnappriatedUndistributedSubsidiaryEarningsMember 2023-12-31 C001789 Regulatory Assetsferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 Helena Golf Course Bank #1 (HELENA), Distribution, Unattended 2023-12-31 C001789 FEA Studiesferc:GenerationStudiesMember 2023-01-012023-12-31 C001789 Iberdrola Renewables Inc. BPAT PPW NF MONTANA OATT BPAT.NWMT BRDY 2023-01-012023-12-31 C001789 Clyde Park, Emigrant, Wood H Frame, 556.5 MCM ACSR 2023-01-012023-12-31 C001789 First Mortgage Bonds 4.85% (South Dakota) 2023-12-31 C001789 Powerex Corporation , SF, Market-Based Rate 2023-01-012023-12-31 C001789 Plains (MISSOULA), Distribution, Unattended 2023-12-31 C001789 EDF Trading North America, LLC NWMT NWMT NF MONTANA OATT HARDIN COLSTRIP 2023-01-012023-12-31 C001789 Stanford Auto A (BILLINGS), Transmission, Unattended 2023-12-31 C001789 Other Coyote 2023-01-012023-12-31 C001789 ferc:UnappriatedUndistributedSubsidiaryEarningsMember Risk Partners Assurance, Ltd. - Equity in Undistributed Earnings 2023-01-012023-12-31 C001789 Great Falls Southeast (GREAT FALLS), Distribution, Unattended 2023-01-012023-12-31 C001789 Basin Electric Power Cooperative NWMT WAUW NF MONTANA OATT COLSTRIP GREATFALLS 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. GWA BPAT SFP MONTANA OATT GLWND1 BPAT.NWMT 2023-01-012023-12-31 C001789 Transalta Energy Marketing (US) Inc. WAPA AVA NF MONTANA OATT CROSSOVER AVAT.NWMT 2023-01-012023-12-31 C001789 Deferred Compensation (South Dakota) 2023-01-012023-12-31 C001789 Western Area Power Administration WAPA NWMT SFP MONTANA OATT GREATFALLS NWMT.SYSTEM 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. NWMT PACE NF MONTANA OATT MATL.NWMT BRDY 2023-01-012023-12-31 C001789 Mill Creek B (BUTTE), Transmission, Unattended 2023-01-012023-12-31 C001789 Montana Tunnels (HELENA), Distribution, Unattended 2023-12-31 C001789 Excess Deferred Income Taxes (South Dakota) 2023-12-31 C001789 Shell Energy North America PPW BPAT NF MONTANA OATT BRDY BPAT.NWMT 2023-01-012023-12-31 C001789 Schroeder (Beethoven Wind) (SD), Transmission, Unattended 2023-01-012023-12-31 C001789 Bozeman Patterson (BOZEMAN), Distribution, Unattended 2023-01-012023-12-31 C001789 Greenfield (NON TIER II QF-1), LU, 2023-01-012023-12-31 C001789 Laurel City (BILLINGS), Distribution, Unattended 2023-12-31 C001789 Delaware Franchise Tax, Franchise Tax, South Dakota, 2023 2023-01-012023-12-31 C001789 Peterson Flats (BUTTE), Transmission, Unattended 2023-01-012023-12-31 C001789 ferc:SalesAndUseTaxMemberferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 Deer Lodge City (BUTTE), Distribution, Unattended 2023-01-012023-12-31 C001789 Big Stone 2023-12-31 C001789 MidAmerican Energy (SOUTH DAKOTA PURCHASES), OS, 2023-01-012023-12-31 C001789 Yankton East Plant B (SD), Transmission, Unattended 2023-01-012023-12-31 C001789 Dynasty Power Inc. NWMT BPAT NF MONTANA OATT MATL.NWMT BPAT.NWMT 2023-01-012023-12-31 C001789 Unbilled Revenues (South Dakota) 2023-12-31 C001789 Hardin City (BILLINGS), Distribution, Unattended 2023-01-012023-12-31 C001789 Highmore ER Interconnect (SD), Transmission, Unattended 2023-12-31 C001789 Beartooth Electric Cooperative, Inc. WAPA & Energy Keepers Inc. Beartooth Electric Cooperative, Inc. FNO Montana OATT Fort Peck & Kerr Various in Montana 2023-01-012023-12-31 C001789 Cycle Power Partners, LLC NWMT PACE NF MONTANA OATT HORSESHOE JEFF 2023-01-012023-12-31 C001789 Kerr, Anaconda B, Wood H Frame, 556.5 MCM ACSR 2023-01-012023-12-31 C001789 SW Freeman (SD), Distribution, Unattended 2023-12-31 C001789 Grand Total 2023-12-31 C001789 Big Stone Plant B (SD), Transmission, Unattended 2023-12-31 C001789 50 Others Under 10,000 KVA (SD), Distribution, Unattended 2023-12-31 C001789 ferc:OtherTaxMember 2023-01-012023-12-31 C001789 ferc:MayMember Montana Operations 2023-01-012023-12-31 C001789 Property Tax - Crow Tribe, Property Tax, Montana, 2023 2023-01-012023-12-31 C001789 Reserves and Accrualsferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 ferc:GasUtilityMember Reserves and Accruals 2023-12-31 C001789 Property Tax, Property Tax, Nebraska, 2023 2023-12-31 C001789 Roundup Auto (BILLINGS), Transmission, Unattended 2023-12-31 C001789 Roosevelt (Tower Falls) 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. WAPA BPAT NF MONTANA OATT GREATFALLS BPAT.NWMT 2023-01-012023-12-31 C001789 Shell Energy North America BPAT AVA NF MONTANA OATT BPAT.NWMT AVAT.NWMT 2023-01-012023-12-31 C001789 Darby (MISSOULA), Distribution, Unattended 2023-12-31 C001789 Billings, Great Falls, Wood H Frame, 1272 KCM ACSR 2023-01-012023-12-31 C001789 Huron City B (SD), Distribution, Unattended 2023-12-31 C001789 First Mortgage Bonds 4.30% (South Dakota) 2023-01-012023-12-31 C001789 Huron City A (SD), Distribution, Unattended 2023-12-31 C001789 State Income Tax, State Tax, South Dakota/Nebraska, 2023 2023-12-31 C001789 Huron West Park C (SD), Transmission, Unattended 2023-12-31 C001789 The Energy Authority WAPA AVA NF MONTANA OATT CROSSOVER AVAT.NWMT 2023-01-012023-12-31 C001789 2188, Madison 2023-12-31 C001789 Rainbow Electric Marketing Corp. AVA NWMT NF MONTANA OATT AVAT.NWMT MATL.NWMT 2023-01-012023-12-31 C001789 Coyote, North Dakota (SD), Transmission, Unattended 2023-01-012023-12-31 C001789 Yankton 2023-01-012023-12-31 C001789 Excess Deferred Income Taxes (Montana) 2023-12-31 C001789 Great Falls 230 Switchyard B (GREAT FALLS), Transmission, Unattended 2023-12-31 C001789 Federal Unemplyment Tax, Unemployment Tax, South Dakota, 2023ferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 ferc:GasUtilityMember Excess Tax Depreciation 2023-12-31 C001789 7%ferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 Glasgow Westside (HAVRE), Distribution, Unattended 2023-01-012023-12-31 C001789 Billings Steam Plant Switchyard B (BILLINGS), Transmission, Unattended 2023-12-31 C001789 Rainbow Electric Marketing Corp. NWMT AVA NF MONTANA OATT CANYONFERRY AVAT.NWMT 2023-01-012023-12-31 C001789 Coyote Coal 2023-01-012023-12-31 C001789 Huron SW (SD), Distribution, Unattended 2023-01-012023-12-31 C001789 First Mortgage Bonds 4.11% (Montana) 2023-12-31 C001789 Big Stone, SD, Gary, SD, H-Wood, 1272 MCM 2023-01-012023-12-31 C001789 Roundup Auto (BILLINGS), Transmission, Unattended 2023-01-012023-12-31 C001789 Broadview, Townsend B, St. Tower, 795 KCM ACSR 2023-01-012023-12-31 C001789 Bozeman East Gallatin Auto (BOZEMAN), Distribution, Unattended 2023-12-31 C001789 Missoula Miller Creek Sub site 2023-01-012023-12-31 C001789 Federal Income Tax, Income Tax, Montana, 2023ferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 Morgan Stanley Capital Group, Inc. GWA BPAT NF MONTANA OATT GLWND1 BPAT.NWMT 2023-01-012023-12-31 C001789 ferc:OctoberMember South Dakota Operations 2023-01-012023-12-31 C001789 Shell Energy North America (US), L.P. , SF, Market-Based Rate 2023-01-012023-12-31 C001789 ferc:FebruaryMember Montana Operations 2023-01-012023-12-31 C001789 Risk Partners Assurance, Ltd. 2023-01-012023-12-31 C001789 Capital Leases (miscellaneous) 2023-01-012023-12-31 C001789 Idaho Power Company , SF, Market-Based Rate 2023-01-012023-12-31 C001789 FAS 106 (Montana) - Docket 93.6.24 and Docket 2009.9.129 2022-12-31 C001789 First Mortgage Bonds 4.26% (South Dakota) 2023-12-31 C001789 ferc:JulyMember South Dakota Operations 2023-01-012023-12-31 C001789 Common Stock 2023-01-012023-12-31 C001789 First Mortgage Bonds 3.98% (Montana) B 2023-01-012023-12-31 C001789 Wagner (SD), Distribution, Unattended 2023-12-31 C001789 Pension Requirement (South Dakota) 2022-12-31 C001789 ferc:TwoYearsMemberferc:SulfurDioxideMember 2022-12-31 C001789 PPLM Share of WET Tax (Montana) 2023-12-31 C001789 Basin Electric Power Cooperative PPW PPW NF MONTANA OATT COLSTRIP MLCK 2023-01-012023-12-31 C001789 ferc:PaidInCapitalMember Havre Pipeline Company - Paid in Capital 2022-12-31 C001789 Powerex Corporation BPAT PPW NF MONTANA OATT BPAT.NWMT BRDY 2023-01-012023-12-31 C001789 Bonneville Power Administration BPAT PPW NF MONTANA OATT BPAT.NWMT YTP 2023-01-012023-12-31 C001789 Two Dot Wind Swyd (BILLINGS), Transmission, Unattended 2023-01-012023-12-31 C001789 First Mortgage Bonds 4.15% (South Dakota) 2023-01-012023-12-31 C001789 Town of Philipsburg Town of Philipsburg Town of Philipsburg FNO Montana OATT Philipsburg Substation Philipsburg, MT 2023-01-012023-12-31 C001789 Federal Income Taxes/State Tax Adjustment 2023-01-012023-12-31 C001789 Transalta Energy Marketing (US) Inc. NWMT PACE NF MONTANA OATT MATL.NWMT BRDY 2023-01-012023-12-31 C001789 ferc:GasUtilityMember Regulatory Assets 2022-12-31 C001789 ferc:SteamProductionPlantMemberferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 Hauser U1 Turb-Gen Upgradeferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 Billings Metra Sub Site 2023-01-012023-12-31 C001789 Rainbow Electric Marketing Corp. 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NWMT WAUW NF MONTANA OATT MATL.NWMT CROSSOVER 2023-01-012023-12-31 C001789 Yankton Hilltop (SD), Transmission, Unattended 2023-12-31 C001789 71 Ranch (NON TIER II QF-1), LU, 2023-01-012023-12-31 C001789 Projects & Studies Prepaid by Customer (South Dakota) 2023-12-31 C001789 Macquarie Energy, LLC PPW NWMT NF MONTANA OATT BRDY NWMT.SYSTEM 2023-01-012023-12-31 C001789 Columbus East (BILLINGS), Distribution, Unattended 2023-12-31 C001789 Mitchell Lake Mitchell (SD), Distribution, Unattended 2023-12-31 C001789 500 kV Operations - Partner's Share (Montana) 2023-01-012023-12-31 C001789 ferc:TransmissionStudiesMember FAC Studies 2023-01-012023-12-31 C001789 BPA Residential Exchange Program (Montana) - Docket 2018.8.49 Order 7630; Annual Amortization 2023-12-31 C001789 Portland General Electric - Colstrip Loss/Startup (EXCHANGES), EX, RS 190 2023-01-012023-12-31 C001789 Powerex Corporation AVA WAPA NF MONTANA OATT AVAT.NWMT CROSSOVER 2023-01-012023-12-31 C001789 Butte Montana St B (BUTTE), Distribution, Unattended 2023-01-012023-12-31 C001789 ferc:GasUtilityMember Excess Tax Depreciation 2023-01-012023-12-31 C001789 Clyde Park (BOZEMAN), Transmission, Unattended 2023-01-012023-12-31 C001789 Mercuria Energy America, LLC WAPA PPW NF MONTANA OATT CROSSOVER BRDY 2023-01-012023-12-31 C001789 Guzman Energy, LLC PPW WAPA NF MONTANA OATT YTP CROSSOVER 2023-01-012023-12-31 C001789 ferc:FuelTaxMember 2022-12-31 C001789 ferc:LandAndRightsMember Montana Operations: 2023-01-012023-12-31 C001789 EDF Trading North America, LLC PACE NWMT NF MONTANA OATT BRDY COLSTRIP 2023-01-012023-12-31 C001789 Billings Exxon (BILLINGS), Distribution, Unattended 2023-12-31 C001789 Western Area Power Administration WAUW NWMT SFP MONTANA OATT GREATFALLS GTFALLSNWMT 2023-01-012023-12-31 C001789 Grant Village 2023-12-31 C001789 ferc:IncomeTaxMemberferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 Mill Creek B (BUTTE), Transmission, Unattended 2023-12-31 C001789 Helena Southside (HELENA), Distribution, Unattended 2023-01-012023-12-31 C001789 Golden Sunlight (BUTTE), Distribution, Unattended 2023-01-012023-12-31 C001789 First Mortgage Bonds 4.15% (Montana) 2023-01-012023-12-31 C001789 Avista Corporation AVA NWMT NF MONTANA OATT AVAT.NWMT COLSTRIP 2023-01-012023-12-31 C001789 ferc:FranchiseTaxMember 2023-01-012023-12-31 C001789 Great Falls 230 Switchyard A (GREAT FALLS), Transmission, Unattended 2023-12-31 C001789 ferc:MiscellaneousOtherTaxMemberferc:ElectricUtilityMember 2023-01-012023-12-31 C001789 SD 11 Resid Space Htg 1 Meter 2023-01-012023-12-31 C001789 CHS (BILLINGS), Distribution, Unattended 2023-12-31 C001789 ferc:ElectricUtilityMember Ashgrove Transformer Upgrade 2023-12-31 C001789 ferc:UnappriatedUndistributedSubsidiaryEarningsMember Canadian Montana Pipeline Corporation - Equity in Undistributed Earnings 2023-12-31 C001789 ferc:OtherAdValoremTaxMember 2023-01-012023-12-31 C001789 MAG Energy Solutions NWMT PACE SFP MONTANA OATT MATL.NWMT JEFF 2023-01-012023-12-31 C001789 Pension/Postretirement Benefits 2023-01-012023-12-31 C001789 Delaware Franchise Tax, Franchise Tax, Montana, 2023 2023-12-31 C001789 Helena Eastside (HELENA), Distribution, Unattended 2023-12-31 C001789 South Cut Bank (GREAT FALLS), Transmission, Unattended 2023-01-012023-12-31 C001789 Montana Resources Energy Keepers, Inc. 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