Consolidated Statement Of Income (Loss) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Revenues:
Operating revenues	$ 7,957	$ 6,394	$ 5,794
Operating Expenses:
Fuel	473	581	490
Purchased power	1,547	606	513
Natural gas purchased for resale	657	442	272
Other operations and maintenance	1,937	1,774	1,661
Depreciation and amortization	1,289	1,146	1,075
Taxes other than income taxes	539	512	483
Total operating expenses	6,442	5,061	4,494
Operating Income	1,515	1,333	1,300
Other Income, Net	226	202	151
Interest Charges	486	383	419
Income Before Income Taxes	1,255	1,152	1,032
Income Taxes	176	157	155
Net Income	1,079	995	877
Less: Net Income Attributable to Noncontrolling Interests	5	5	6
Net Income Attributable to Ameren Common Shareholders	1,074	990	871
Pension and other postretirement benefit plan activity, net of income taxes (benefit)	(14)	14	16
Comprehensive Income	1,065	1,009	893
Less: Comprehensive Income Attributable to Noncontrolling Interests	5	5	6
Comprehensive Income Attributable to Ameren Common Shareholders	$ 1,060	$ 1,004	$ 887
Earnings per Common Share – Basic
Earnings per Common Share – Basic	$ 4.16	$ 3.86	$ 3.53
Earnings per Common Share – Diluted
Earnings per Common Share – Diluted	$ 4.14	$ 3.84	$ 3.50
Weighted-average Common Shares Outstanding – Basic	258.4	256.3	247.0
Weighted-average Common Shares Outstanding – Diluted	259.5	257.6	248.7
Union Electric Company
Operating Revenues:
Operating revenues	$ 4,046	$ 3,353	$ 3,109
Operating Expenses:
Fuel	473	581	490
Purchased power	677	227	171
Natural gas purchased for resale	104	60	43
Other operations and maintenance	1,028	948	886
Depreciation and amortization	732	632	604
Taxes other than income taxes	363	343	328
Total operating expenses	3,377	2,791	2,522
Operating Income	669	562	587
Other Income, Net	99	99	76
Interest Charges	213	137	190
Income Before Income Taxes	555	524	473
Income Taxes	(10)	3	34
Net Income	565	521	439
Preferred Stock Dividends	3	3	3
Net Income Attributable to Ameren Common Shareholders	562	518	436
Ameren Illinois Company
Operating Revenues:
Operating revenues	3,756	2,895	2,535
Operating Expenses:
Purchased power	880	400	355
Natural gas purchased for resale	553	382	229
Other operations and maintenance	882	820	775
Depreciation and amortization	514	472	434
Taxes other than income taxes	161	153	140
Total operating expenses	2,990	2,227	1,933
Operating Income	766	668	602
Other Income, Net	96	66	59
Interest Charges	168	164	155
Income Before Income Taxes	694	570	506
Income Taxes	179	143	124
Net Income	515	427	382
Preferred Stock Dividends	2	2	3
Net Income Attributable to Ameren Common Shareholders	513	425	379
Electric
Operating Revenues:
Operating revenues	6,581	5,297	4,911
Electric | Union Electric Company
Operating Revenues:
Operating revenues	3,849	3,212	2,984
Electric | Ameren Illinois Company
Operating Revenues:
Operating revenues	2,576	1,938	1,775
Natural gas
Operating Revenues:
Operating revenues	1,376	1,097	883
Natural gas | Union Electric Company
Operating Revenues:
Operating revenues	197	141	125
Natural gas | Ameren Illinois Company
Operating Revenues:
Operating revenues	$ 1,180	$ 957	$ 760