v3.26.3
Other Income, Net (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Other Nonoperating Income (Expense) [Line Items]        
Allowance for equity funds used during construction $ 35 $ 21 $ 104 $ 60
Other interest income 8 10 24 31
Non-service cost components of net periodic benefit income 45 59 143 187
Miscellaneous income 7 6 17 13
Income (Loss) from Equity Method Investments 24 (9) 48 (19)
Donations (1) (6) (5) (9)
Miscellaneous expense (6) (5) (15) (14)
Total Other Income, Net 112 76 320 257
Gain (Loss) on Extinguishment of Debt 0 0 4 8
Union Electric Company        
Other Nonoperating Income (Expense) [Line Items]        
Allowance for equity funds used during construction 27 14 80 37
Other interest income 3 3 8 7
Non-service cost components of net periodic benefit income 30 29 89 96
Miscellaneous income 3 4 5 6
Donations (1) (2) (3) (4)
Miscellaneous expense (4) (3) (8) (7)
Total Other Income, Net 58 45 171 135
Defined Benefit Plan, Non-service Cost or Income Components - Tracker (19) (9) (59) (41)
Ameren Illinois Company        
Other Nonoperating Income (Expense) [Line Items]        
Allowance for equity funds used during construction 6 6 20 21
Other interest income 5 7 16 24
Non-service cost components of net periodic benefit income 12 21 41 61
Miscellaneous income 4 2 11 7
Donations 0 (4) (2) (5)
Miscellaneous expense (2) (2) (6) (7)
Total Other Income, Net $ 25 $ 30 $ 80 $ 101