v3.25.2
Fair Value Measurements (Fair Value Of Net Derivative Assets (Liabilities)) (Details) - Commodity Contracts [Member] - USD ($)
$ in Millions
Jun. 30, 2025
Mar. 31, 2025
Dec. 31, 2024
Jun. 30, 2024
Mar. 31, 2024
Dec. 31, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Fair value, net derivative assets $ 56 $ 9 $ 25 $ 51 $ 7 $ 24
Excluding Financial Transmission Rights [Member]            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Fair value, net derivative assets 6   0      
Financial Transmission Rights [Member]            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Fair value, net derivative assets 50   25      
IPL [Member]            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Fair value, net derivative assets 44 9 20 40 5 19
IPL [Member] | Excluding Financial Transmission Rights [Member]            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Fair value, net derivative assets 6   0      
IPL [Member] | Financial Transmission Rights [Member]            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Fair value, net derivative assets 38   20      
WPL [Member]            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Fair value, net derivative assets 12 $ 0 5 $ 11 $ 2 $ 5
WPL [Member] | Excluding Financial Transmission Rights [Member]            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Fair value, net derivative assets 0   0      
WPL [Member] | Financial Transmission Rights [Member]            
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Fair value, net derivative assets $ 12   $ 5