v3.25.2
Overview and Summary of Significant Accounting Policies (Details)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2025
USD ($)
generating_station
MW
Jun. 30, 2024
USD ($)
Jun. 30, 2025
USD ($)
generating_station
MW
Jun. 30, 2024
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]            
Income Tax Expense (Benefit) $ 6,635 $ 12,610 $ 42,575 $ 16,519    
Accumulated Other Comprehensive Income (Loss), Net of Tax 34,510   34,510   $ 35,378 $ 29,294
Inventories $ 40,607   $ 40,607   50,842  
Number of customers 531,000   531,000      
Number of generating stations | generating_station 4   4      
Regulatory assets, current $ 50,690   $ 50,690   49,093  
Inventory, Net 91,297   91,297   99,935  
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent (434) (434) (868) 326    
Capitalized Computer Software, Amortization 6,231 6,788 13,901 13,728    
Business Combination, Achieved in Stages, Preacquisition Equity Interest in Acquiree, Remeasurement, Gain (Loss) 159 (14) 164 (1,537)    
Allowance for Funds Used During Construction, Capitalized Interest 6,600 6,411 16,416 11,687    
Allowance for Funds Used During Construction, Equity Portion 732 1,269 1,401 2,100    
Capitalized Computer Software, Gross 286,261   286,261   280,020  
Project development intangible assets 146,661   146,661   83,149  
Emissions Allowance 797   797   797  
Capitalized Computer Software, Accumulated Amortization (145,619)   (145,619)   (131,756)  
Intangible Assets, Net (Including Goodwill) 288,100   $ 288,100   232,210  
Petersburg Energy Center Project MW     250      
Petersburg Energy Storage Project MW     45      
Petersburg Energy Storage Project MwH     180      
Hardy Hills Solar Project MW     195      
Hoosier Wind Project MW     106      
Pike Co BESS Project MW     200      
Pike Co BESS Project MwH     800      
Liabilities 5,634,561   $ 5,634,561   5,747,914  
Payments to Noncontrolling Interests     (45,223) 0    
Investment Tax Credit     133,010 0    
Income Taxes Receivable 45,223   45,223   0  
Investment Tax Credit     133,010 0    
Accrued taxes $ 25,935   25,935   $ 26,253  
Payments to Noncontrolling Interests     (45,223) 0    
ITC            
Payments to Noncontrolling Interests     45,200      
Payments to Noncontrolling Interests     $ 45,200      
Aes U.S. Investments [Member]            
Ownership percentage by parent (percent) 82.35%   82.35%      
CDPQ [Member]            
Ownership percentage by parent (percent) 17.65%   17.65%      
Ownership interest in parent company (percent) 15.00%   15.00%      
AES U.S. Holdings, LLC [Member]            
Ownership interest in parent company (percent) 85.00%   85.00%      
ITC            
Payments to Noncontrolling Interests     $ 87,800      
Investment Tax Credit     133,000      
Investment Tax Credit     133,000      
Payments to Noncontrolling Interests     $ 87,800      
Harding Street [Member]            
Amount of New Operation for Battery Storage Unit, megawatts | MW 20   20      
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent            
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]            
Interest and Debt Expense $ 578 578 $ 1,156 (434)    
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent            
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]            
Income Tax Expense (Benefit) (144) (144) (288) 108    
Variable Interest Entity, Primary Beneficiary            
Property, Plant and Equipment, Gross 1,391,300 1,169,300 1,391,300 1,169,300    
Liabilities $ 247,800 $ 180,500 $ 247,800 $ 180,500    
Subsidiaries [Member]            
Electric generation capability for winter, megawatts | MW 3,070   3,070      
Electric generation capability for summer, megawatts | MW 2,925   2,925