Related Party Transactions (Schedule of Related Party Electric Power Supply Agreements) (Details) - Ameren Illinois Company - Ameren Illinois Power Supply Agreements with Ameren Missouri	12 Months Ended
	Dec. 31, 2022 MWh $ / MWh
April 2019 Procurement
Schedule of Related Party Electric Power Supply Agreements [Line Items]
Related Party Long Term Contract For Purchase Of Electric Power | MWh	288,000
Related Party Long Term Contract For Purchase Of Electric Power Rate | $ / MWh	35
September 2019 Procurement
Schedule of Related Party Electric Power Supply Agreements [Line Items]
Related Party Long Term Contract For Purchase Of Electric Power | MWh	170,800
Related Party Long Term Contract For Purchase Of Electric Power Rate | $ / MWh	29
September 2020 Procurement
Schedule of Related Party Electric Power Supply Agreements [Line Items]
Related Party Long Term Contract For Purchase Of Electric Power | MWh	204,800
Related Party Long Term Contract For Purchase Of Electric Power Rate | $ / MWh	31
April 2021 Procurement
Schedule of Related Party Electric Power Supply Agreements [Line Items]
Related Party Long Term Contract For Purchase Of Electric Power | MWh	33,600
Related Party Long Term Contract For Purchase Of Electric Power Rate | $ / MWh	34
September 2021 Procurement
Schedule of Related Party Electric Power Supply Agreements [Line Items]
Related Party Long Term Contract For Purchase Of Electric Power | MWh	136,000
Related Party Long Term Contract For Purchase Of Electric Power Rate | $ / MWh	37