Rate And Regulatory Matters (Narrative-Federal) (Details) - USD ($) $ in Millions |
1 Months Ended | 6 Months Ended | ||||
|---|---|---|---|---|---|---|
Oct. 31, 2024 |
May 31, 2020 |
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2024 |
Dec. 31, 2024 |
|
| Rate And Regulatory Matters [Line Items] | ||||||
| Capital expenditures | $ 2,130 | $ 1,892 | ||||
| Forecast | ||||||
| Rate And Regulatory Matters [Line Items] | ||||||
| Capital expenditures | $ 1,300 | |||||
| Ameren Illinois Company | ||||||
| Rate And Regulatory Matters [Line Items] | ||||||
| Capital expenditures | 742 | $ 717 | ||||
| Current regulatory liabilities | 76 | $ 79 | ||||
| Midwest Independent Transmission System Operator, Inc | Final Rate Order | ||||||
| Rate And Regulatory Matters [Line Items] | ||||||
| Approved return on equity percentage | 9.98% | 10.02% | ||||
| Current regulatory liabilities | 11 | |||||
| Midwest Independent Transmission System Operator, Inc | Final Rate Order | Ameren Illinois Company | ||||||
| Rate And Regulatory Matters [Line Items] | ||||||
| Current regulatory liabilities | $ 7 | |||||