Summary Of Significant Accounting Policies - Schedule of Other Assets and Other Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Accounting Policies [Line Items]
Other current assets	$ 162	$ 139
Regulatory Asset, Noncurrent	2,397	1,810
Long-Term Debt, Current Maturities	317	849
Interest accrued	196	147
Long-Term Debt, Excluding Current Maturities	17,262	$ 15,121
Ameren Missouri Securitization Funding I, LLC
Accounting Policies [Line Items]
Other current assets	2
Regulatory Asset, Noncurrent	465
Long-Term Debt, Current Maturities	17
Interest accrued	1
Long-Term Debt, Excluding Current Maturities	$ 448