Other Income, Net (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Other Nonoperating Income (Expense) [Line Items]
Allowance for equity funds used during construction	$ 16	$ 14	$ 25	$ 23
Other interest income	13	9	21	17
Non-service cost components of net periodic benefit income	76	63	152	127
Miscellaneous income	4	2	6	4
Income (Loss) from Equity Method Investments	1	0	1	2
Donations	(2)	(2)	(4)	(4)
Miscellaneous expense	(5)	(4)	(9)	(9)
Total Other Income, Net	103	82	192	160
Union Electric Company
Other Nonoperating Income (Expense) [Line Items]
Allowance for equity funds used during construction	14	8	23	12
Other interest income	3	2	5	6
Non-service cost components of net periodic benefit income	35	14	69	28
Miscellaneous income	0	1	2	2
Donations	(1)	(1)	(2)	(2)
Miscellaneous expense	(2)	(2)	(4)	(5)
Total Other Income, Net	49	22	93	41
Defined Benefit Plan, Non-service Cost or Income Components - Tracker	(11)	17	(20)	34
Ameren Illinois Company
Other Nonoperating Income (Expense) [Line Items]
Allowance for equity funds used during construction	2	6	2	10
Other interest income	9	6	15	10
Non-service cost components of net periodic benefit income	26	31	53	62
Miscellaneous income	2	1	3	2
Donations	(1)	(1)	(2)	(2)
Miscellaneous expense	(1)	(2)	(3)	(4)
Total Other Income, Net	$ 37	$ 41	$ 68	$ 78