Related Party Transactions (Schedule of Related Party Electric Power Supply Agreements) (Details) - Ameren Illinois - Ameren Illinois Power Supply Agreements with Ameren Missouri	12 Months Ended
	Dec. 31, 2023 MWh $ / MWh
April 2019
Schedule of Related Party Electric Power Supply Agreements [Line Items]
MWhs | MWh	288,000
Average Price per MWh | $ / MWh	35
September 2019
Schedule of Related Party Electric Power Supply Agreements [Line Items]
MWhs | MWh	170,800
Average Price per MWh | $ / MWh	29
September 2020
Schedule of Related Party Electric Power Supply Agreements [Line Items]
MWhs | MWh	204,800
Average Price per MWh | $ / MWh	31
April 2021
Schedule of Related Party Electric Power Supply Agreements [Line Items]
MWhs | MWh	33,600
Average Price per MWh | $ / MWh	34
September 2021
Schedule of Related Party Electric Power Supply Agreements [Line Items]
MWhs | MWh	136,000
Average Price per MWh | $ / MWh	37