Other Income, Net (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Other Nonoperating Income (Expense) [Line Items]
Allowance for equity funds used during construction	$ 14	$ 11	$ 23	$ 19
Interest income on industrial development revenue bonds	0	6	1	12
Non-service cost components of net periodic benefit income	63	47	127	93
Miscellaneous income	11	5	20	9
Income (Loss) from Equity Method Investments	0	1	2	4
Donations	(2)	(2)	(4)	(4)
Miscellaneous expense	(4)	(6)	(9)	(11)
Total Other Income, Net	82	62	160	122
Union Electric Company
Other Nonoperating Income (Expense) [Line Items]
Allowance for equity funds used during construction	8	6	12	10
Interest income on industrial development revenue bonds	0	6	1	12
Non-service cost components of net periodic benefit income	14	14	28	28
Miscellaneous income	3	1	7	3
Donations	(1)	(1)	(2)	(2)
Miscellaneous expense	(2)	(2)	(5)	(4)
Total Other Income, Net	22	24	41	47
Defined Benefit Plan, Non-service Cost or Income Components - Tracker	17	5	34	11
Ameren Illinois Company
Other Nonoperating Income (Expense) [Line Items]
Allowance for equity funds used during construction	6	5	10	9
Non-service cost components of net periodic benefit income	31	21	62	42
Miscellaneous income	7	3	12	5
Donations	(1)	(1)	(2)	(2)
Miscellaneous expense	(2)	(3)	(4)	(5)
Total Other Income, Net	$ 41	$ 25	$ 78	$ 49