Audit Information	12 Months Ended
	Dec. 31, 2021
Auditor [Line Items]
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	St. Louis, Missouri
Auditor Firm ID	238
Union Electric Company
Auditor [Line Items]
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	St. Louis, Missouri
Auditor Firm ID	238
Ameren Illinois Company
Auditor [Line Items]
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	St. Louis, Missouri
Auditor Firm ID	238