Income Taxes (Narrative) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Income Taxes [Line Items] | ||||
| Asset valuation charge for IPL's Lansing Generating Station | $ 0 | $ 60 | $ 0 | $ 60 |
| Steam Plant [Member] | ||||
| Income Taxes [Line Items] | ||||
| Asset retirement obligation charge for IPL's steam assets | 20 | 20 | ||
| IPL [Member] | ||||
| Income Taxes [Line Items] | ||||
| Asset valuation charge for IPL's Lansing Generating Station | 0 | 60 | 0 | 60 |
| Asset retirement obligation charge for IPL's steam assets | $ 84 | 102 | $ 169 | 187 |
| IPL [Member] | Steam Plant [Member] | ||||
| Income Taxes [Line Items] | ||||
| Asset retirement obligation charge for IPL's steam assets | $ 20 | $ 20 | ||