v3.26.1
Segment Information (Narrative) (Details)
6 Months Ended
Jun. 30, 2026
segment
Segment Reporting [Line Items]  
Number of reportable segments 4
Union Electric Company  
Segment Reporting [Line Items]  
Number of reportable segments 1
Ameren Illinois Company  
Segment Reporting [Line Items]  
Number of reportable segments 3