Consolidated Statement Of Cash Flows (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Interest Paid, Capitalized, Investing Activities	$ 56	$ 48	$ 26
Proceeds from Income Tax Refunds	95	49	0
Ameren Missouri
Interest Paid, Capitalized, Investing Activities	39	27	13
Proceeds from Income Tax Refunds	95	49	0
Ameren Illinois
Interest Paid, Capitalized, Investing Activities	$ 15	$ 17	$ 12