XML 134 R107.htm IDEA: XBRL DOCUMENT v3.25.4
PROPERTY, PLANT AND EQUIPMENT AND JOINTLY-OWNED PROJECTS: Property, Plant and Equipmnt Level 4 (Details)
 12 Months Ended
Dec. 31, 2025
USD ($)
MWh
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Public Utility, Property, Plant and Equipment      
Production $ 2,675,671,000 $ 2,858,678,000  
Transmission 1,653,490,000 1,534,474,000  
Energy Storage [1] 509,740,000 393,012,000  
Distribution [1] 2,658,849,000 2,465,423,000  
General and Other 751,356,000 706,176,000  
Utility plant in service 8,249,106,000 7,957,763,000  
Accumulated provision for depreciation (2,599,465,000) (2,714,706,000)  
Utility plant in service - net $ 5,649,641,000 $ 5,243,057,000  
Average depreciation rate 3.20% 3.10% 2.90%
Idaho Energy Resources Co. Coal purchases from Bridger Coal Company $ 253,236,000 $ 259,204,000 $ 275,405,000
Regulatory Liabilities $ 1,052,151,000 $ 984,326,000  
Jim Bridger Plant      
Public Utility, Property, Plant and Equipment      
Jointly Owned Utility Plant, Name Jim Bridger units 1-4    
Jointly Owned Utility Plant, Gross Ownership Amount of Plant in Service $ 777,096,000    
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress 780,000    
Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation $ 575,151,000    
Jointly Owned Utility Plant, Proportionate Ownership Share 33.00%    
Nameplate Capacity (in MW) | MWh [2] 775    
Valmy Plant      
Public Utility, Property, Plant and Equipment      
Jointly Owned Utility Plant, Name North Valmy units 1 & 2(2)    
Jointly Owned Utility Plant, Gross Ownership Amount of Plant in Service [3] $ 42,113,000    
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress [3] 21,118,000    
Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation [3] $ (128,000)    
Jointly Owned Utility Plant, Proportionate Ownership Share [3] 50.00%    
Nameplate Capacity (in MW) | MWh [2],[3] 284    
Production      
Public Utility, Property, Plant and Equipment      
Average depreciation rate 4.02% 3.90%  
Transmission      
Public Utility, Property, Plant and Equipment      
Average depreciation rate 1.91% 1.89%  
Electric Energy Storage      
Public Utility, Property, Plant and Equipment      
Average depreciation rate [1] 5.06% 3.61%  
Distribution      
Public Utility, Property, Plant and Equipment      
Average depreciation rate [1] 2.17% 2.16%  
General and Other      
Public Utility, Property, Plant and Equipment      
Average depreciation rate 5.27% 5.18%  
Bridger Coal Company      
Public Utility, Property, Plant and Equipment      
Idaho Energy Resources Co. Coal purchases from Bridger Coal Company $ 54,400,000 $ 51,600,000 67,900,000
Idaho Power Company      
Public Utility, Property, Plant and Equipment      
Utility plant in service 8,249,106,000 7,957,763,000  
Accumulated provision for depreciation (2,599,465,000) (2,714,706,000)  
Utility plant in service - net $ 5,649,641,000 $ 5,243,057,000  
Average depreciation rate 3.18% 3.06%  
Idaho Energy Resources Co. Coal purchases from Bridger Coal Company $ 253,236,000 $ 259,204,000 $ 275,405,000
Construction work in progress 1,700,000,000    
Hells Canyon Complex | Idaho Power Company      
Public Utility, Property, Plant and Equipment      
Construction work in progress 536,100,000    
Deferred revenue-AFUDC      
Public Utility, Property, Plant and Equipment      
Regulatory Liabilities [4] $ 280,979,000 $ 250,942,000  
[1] The presentation of the major classifications of Idaho Power's utility plant in service in the table above has been modified to separately report the energy storage balance for the years ended December 31, 2025 and 2024. The prior year energy storage balance, which had previously been classified in the distribution balance, has been reclassified to conform with the current year presentation. This change reflects a shift from one acceptable presentation to another to enhance transparency.
[2] Idaho Power’s share of nameplate capacity.
[3] Pursuant to an agreement with NV Energy, Idaho Power ceased participation in coal-fired operations of North Valmy in December 2019 at unit 1 and December 2025 at unit 2. Idaho Power's 2025 IRP identified a preferred resource portfolio and action plan that includes the conversion of the two generating units at the North Valmy plant from coal to natural gas by mid-2026. The conversion of Unit 1 has been completed and the unit was placed in-service in December 2025, and conversion of Unit 2 is expected to be completed by mid-2026.
[4] Idaho Power is collecting revenue in the Idaho jurisdiction for AFUDC on HCC relicensing costs but is deferring revenue recognition of the amounts collected until the license is issued and the asset is placed in service under the new license.