Consolidated Statement Of Income (Loss) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating Revenues:
Operating revenues	$ 7,623	$ 7,500	$ 7,957
Operating Expenses:
Utilities Operating Expense, Fuel Used and Purchased Power	1,681	1,812	2,020
Natural gas purchased for resale	320	355	657
Other operations and maintenance	1,969	1,866	1,937
Depreciation and amortization	1,590	1,387	1,289
Taxes other than income taxes	547	522	539
Total operating expenses	6,107	5,942	6,442
Operating Income	1,516	1,558	1,515
Other Income, Net	417	348	226
Interest Charges	663	566	486
Income Before Income Taxes	1,270	1,340	1,255
Income Taxes	83	183	176
Net Income	1,187	1,157	1,079
Less: Net Income Attributable to Noncontrolling Interests	5	5	5
Net Income Attributable to Ameren Common Shareholders	1,182	1,152	1,074
Pension and other postretirement benefit plan activity, net of income taxes (benefit) of $—, $(2), and $(4), respectively	(3)	(5)	(14)
Unrealized net gain on derivative hedging instruments, net of income taxes of $—, $—, and $—, respectively	3	0	0
Comprehensive Income	1,187	1,152	1,065
Less: Comprehensive Income Attributable to Noncontrolling Interests	5	5	5
Comprehensive Income Attributable to Ameren Common Shareholders	1,182	1,147	1,060
Preferred Stock Dividends	$ 5	$ 5	$ 5
Earnings per Common Share – Basic
Earnings per Common Share – Basic	$ 4.43	$ 4.39	$ 4.16
Earnings per Common Share – Diluted
Earnings per Common Share – Diluted	$ 4.42	$ 4.38	$ 4.14
Weighted-average Common Shares Outstanding – Basic	266.8	262.8	258.4
Weighted-average Common Shares Outstanding – Diluted	267.4	263.4	259.5
Ameren Missouri
Operating Revenues:
Operating revenues	$ 3,993	$ 3,859	$ 4,046
Operating Expenses:
Utilities Operating Expense, Fuel Used and Purchased Power	1,071	997	1,150
Natural gas purchased for resale	60	79	104
Other operations and maintenance	1,050	1,003	1,028
Depreciation and amortization	917	783	732
Taxes other than income taxes	372	360	363
Total operating expenses	3,470	3,222	3,377
Operating Income	523	637	669
Other Income, Net	196	130	99
Interest Charges	244	227	213
Income Before Income Taxes	475	540	555
Income Taxes	(87)	(8)	(10)
Net Income	562	548	565
Net Income Attributable to Ameren Common Shareholders	559	545	562
Preferred Stock Dividends	3	3	3
Ameren Illinois
Operating Revenues:
Operating revenues	3,472	3,482	3,756
Operating Expenses:
Purchased power	621	820	880
Natural gas purchased for resale	260	276	553
Other operations and maintenance	906	818	882
Depreciation and amortization	619	556	514
Taxes other than income taxes	157	146	161
Total operating expenses	2,563	2,616	2,990
Operating Income	909	866	766
Other Income, Net	147	156	96
Interest Charges	241	204	168
Income Before Income Taxes	815	818	694
Income Taxes	193	209	179
Net Income	622	609	515
Net Income Attributable to Ameren Common Shareholders	620	607	513
Preferred Stock Dividends	2	2	2
Electric
Operating Revenues:
Operating revenues	6,540	6,439	6,581
Electric | Ameren Missouri
Operating Revenues:
Operating revenues	3,847	3,694	3,849
Electric | Ameren Illinois
Operating Revenues:
Operating revenues	2,534	2,585	2,576
Natural gas
Operating Revenues:
Operating revenues	1,083	1,061	1,376
Natural gas | Ameren Missouri
Operating Revenues:
Operating revenues	146	165	197
Natural gas | Ameren Illinois
Operating Revenues:
Operating revenues	$ 938	$ 897	$ 1,180