v3.25.2
Related Parties (Service Agreements) (Details) - Corporate Services [Member] - Subsidiary of Common Parent [Member] - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Corporate Services Billings [Member] | IPL [Member]        
Related Party Transactions [Line Items]        
Amounts billed between related parties $ 50 $ 49 $ 97 $ 92
Corporate Services Billings [Member] | WPL [Member]        
Related Party Transactions [Line Items]        
Amounts billed between related parties 48 46 95 86
Sales Credited [Member] | IPL [Member]        
Related Party Transactions [Line Items]        
Amounts billed between related parties 1 0 2 0
Sales Credited [Member] | WPL [Member]        
Related Party Transactions [Line Items]        
Amounts billed between related parties 40 14 62 36
Purchases Billed [Member] | IPL [Member]        
Related Party Transactions [Line Items]        
Amounts billed between related parties 107 105 200 201
Purchases Billed [Member] | WPL [Member]        
Related Party Transactions [Line Items]        
Amounts billed between related parties $ 16 $ 16 $ 35 $ 23