Consolidated Balance Sheet - UE (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Accounts receivable - trade, allowance for doubtful accounts	$ 30	$ 31
Common Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	400,000,000.0	400,000,000.0
Common Stock, Shares, Outstanding	266,300,000	262,000,000.0
Ameren Missouri
Accounts receivable - trade, allowance for doubtful accounts	$ 12	$ 13
Common Stock, No Par Value (in dollars per share)	$ 5	$ 5
Common stock, shares authorized	150,000,000.0	150,000,000.0
Common Stock, Shares, Outstanding	102,100,000	102,100,000