Short-Term Debt And Liquidity (Narrative) (Details) $ in Billions	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2021	Sep. 30, 2022 USD ($)	Sep. 30, 2021
Credit Agreements
Short-term Debt [Line Items]
Net Liquidity Available	$ 1.1		$ 1.1
Actual debt-to-capital ratio	0.59		0.59
Utilities
Short-term Debt [Line Items]
Short-term Debt, Weighted Average Interest Rate, over Time	2.48%	0.06%	1.29%	0.17%
Union Electric Company | Missouri Credit Agreement
Short-term Debt [Line Items]
Actual debt-to-capital ratio	0.49		0.49
Ameren Illinois Company | Illinois Credit Agreement
Short-term Debt [Line Items]
Actual debt-to-capital ratio	0.45		0.45