SEGMENT INFORMATION
Ameren has four segments: Ameren Missouri, Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, and Ameren Transmission. The Ameren Missouri segment includes all of the operations of Ameren Missouri. Ameren Illinois Electric Distribution consists of the electric distribution business of Ameren Illinois. Ameren Illinois Natural Gas consists of the natural gas business of Ameren Illinois. Ameren Transmission primarily consists of the aggregated electric transmission businesses of Ameren Illinois and ATXI. The category called Other primarily includes Ameren (parent) activities and Ameren Services.
Ameren Missouri has one segment. Ameren Illinois has three segments: Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, and Ameren Illinois Transmission. See Note 1 – Summary of Significant Accounting Policies for additional information regarding the operations of Ameren Missouri, Ameren Illinois, and ATXI.
Segment operating revenues and a majority of operating expenses are directly recognized and incurred by Ameren Illinois in each Ameren Illinois segment. Common operating expenses, miscellaneous income and expenses, interest charges, and income tax expense are allocated by Ameren Illinois to each Ameren Illinois segment based on certain factors, which primarily relate to the nature of the cost. Additionally, Ameren Illinois Transmission earns revenue from transmission service provided to Ameren Illinois Electric Distribution, other retail electric suppliers, and wholesale customers. The transmission expense for Illinois customers who have elected to purchase their power from Ameren Illinois is recovered through a cost recovery mechanism with no net effect on Ameren Illinois Electric Distribution earnings, as costs are offset by corresponding revenues. Transmission revenues from these transactions are reflected in Ameren Transmission’s and Ameren Illinois Transmission’s operating revenues. An intersegment elimination at Ameren and Ameren Illinois occurs to eliminate these transmission revenues and expenses.
The CODMs for Ameren, Ameren Missouri, and Ameren Illinois are the Chief Executive Officer of Ameren, the Group President of Ameren Utilities of Ameren, and the Chief Financial Officer of Ameren. The CODMs use net income to evaluate income generated from the segments to make decisions about resources allocated to each segment and assess segment performance. Net income is also used to monitor budget versus actual results when assessing segment performance.
The following tables present information about the reported revenue and specified items reflected in net income attributable to common shareholders and capital expenditures by segment at Ameren and Ameren Illinois for the years ended December 31, 2025, 2024, and 2023. Ameren, Ameren Missouri, and Ameren Illinois management review segment capital expenditure information rather than any individual or total asset amount.
Ameren
Reportable Segments
Ameren MissouriAmeren Illinois Electric DistributionAmeren Illinois Natural GasAmeren TransmissionOtherIntersegment EliminationsAmeren
2025
External revenues$4,763 $2,393 $968 $675 $ $ $8,799 
Intersegment revenues32 6  187  (225) 
Revenue4,795 2,399 968 862  (225)8,799 
Fuel and purchased power(a)
(1,538)(941)   173 (2,306)
Natural gas purchased for resale(a)
(65) (283)   (348)
Other operations and maintenance expenses(a)
(1,029)(656)(233)(74)(34)52 (1,974)
Other segment items
Depreciation and amortization(860)(373)(128)(199)(8) (1,568)
Taxes other than income taxes(393)(82)(82)(9)(11) (577)
Other income, net180 89 19 24 42 (7)347 
Interest charges(297)(107)(65)(120)
(b)
(194)7 (776)
Income taxes (benefit)(43)(47)(38)(68)60  (136)
Noncontrolling interests – preferred stock dividends(3)(1) (1)  (5)
Net income (loss) attributable to Ameren common shareholders$747 $281 $158 $415 $(145)$ $1,456 
Interest income$9 $30 $ $3 $6 $(7)$41 
Capital expenditures2,502 635 283 717 8 (17)4,128 
2024
External revenues$3,960 $2,088 $938 $637 $— $— $7,623 
Intersegment revenues33 — 144 — (178)— 
Revenue3,993 2,089 938 781 — (178)7,623 
Fuel and purchased power(a)
(1,071)(740)— — — 130 (1,681)
Natural gas purchased for resale(a)
(60)— (260)— — — (320)
Other operations and maintenance expenses(a)
(1,050)(619)(230)(70)(48)48 (1,969)
Other segment items
Depreciation and amortization(917)(369)(129)(167)(8)— (1,590)
Taxes other than income taxes(372)(75)(78)(9)(13)— (547)
Other income, net196 97 27 26 83 (12)417 
Interest charges(244)(98)(63)(117)
(b)
(153)12 (663)
Income taxes (benefit)87 (50)(56)(120)56 — (83)
Noncontrolling interests – preferred stock dividends(3)(1)— (1)— — (5)
Net income (loss) attributable to Ameren common shareholders$559 $234 $149 $323 $(83)$— $1,182 
Interest income$$28 $$$10 $(12)$41 
Capital expenditures2,712 579 264 758 (1)4,319 
Reportable Segments
Ameren MissouriAmeren Illinois Electric DistributionAmeren Illinois Natural GasAmeren TransmissionOtherIntersegment EliminationsAmeren
2023
External revenues$3,825 $2,217 $897 $561 $— $— $7,500 
Intersegment revenues34 — 116 — (151)— 
Revenue3,859 2,218 897 677 — (151)7,500 
Fuel and purchased power(a)
(997)(933)— — — 118 (1,812)
Natural gas purchased for resale(a)
(79)— (276)— — — (355)
Other operations and maintenance expenses(a)
(1,003)(532)(237)(60)(67)33 (1,866)
Other segment items
Depreciation and amortization(783)(351)(108)(138)(7)— (1,387)
Taxes other than income taxes(360)(75)(67)(8)(12)— (522)
Other income, net130 103 30 28 62 (5)348 
Interest charges(227)(89)(55)(96)
(b)
(104)(566)
Income taxes (benefit)(82)(50)(106)47 — (183)
Noncontrolling interests – preferred stock dividends(3)(1)— (1)— — (5)
Net income (loss) attributable to Ameren common shareholders$545 $258 $134 $296 $(81)$— $1,152 
Interest income$11 $19 $$$$(5)$33 
Capital expenditures1,760 752 299 804 (27)3,597 
(a)Significant segment expense that is regularly provided to the CODMs. Intersegment expenses are included within the amounts shown.
(b)Ameren Transmission interest charges include an allocation of financing costs from Ameren (parent).
Ameren Illinois
Reportable Segments
Ameren Illinois Electric DistributionAmeren Illinois
Natural Gas
Ameren Illinois TransmissionIntersegment EliminationsAmeren Illinois
2025
External revenues$2,399 $968 $477 $ $3,844 
Intersegment revenues  160 (160) 
Revenue2,399 968 637 (160)3,844 
Purchased power(a)
(941)  160 (781)
Natural gas purchased for resale(a)
 (283)  (283)
Other operations and maintenance expenses(a)
(656)(233)(56) (945)
Other segment items
Depreciation and amortization(373)(128)(151) (652)
Taxes other than income taxes(82)(82)(5) (169)
Other income, net89 19 28  136 
Interest charges(107)(65)(88) (260)
Income taxes(47)(38)(68) (153)
Noncontrolling interests – preferred stock dividends(1) (1) (2)
Net income available to common shareholder$281 $158 $296 $ $735 
Interest income$30 $ $2 $ $32 
Capital expenditures635 283 563  1,481 
2024
External revenues$2,089 $938 $445 $— $3,472 
Intersegment revenues— — 119 (119)— 
Revenue2,089 938 564 (119)3,472 
Purchased power(a)
(740)— — 119 (621)
Natural gas purchased for resale(a)
— (260)— — (260)
Other operations and maintenance expenses(a)
(619)(230)(57)— (906)
Other segment items
Depreciation and amortization(369)(129)(121)— (619)
Taxes other than income taxes(75)(78)(4)— (157)
Other income, net97 27 23 — 147 
Interest charges(98)(63)(80)— (241)
Income taxes(50)(56)(87)— (193)
Noncontrolling interests – preferred stock dividends(1)— (1)— (2)
Net income available to common shareholder$234 $149 $237 $— $620 
Interest income$28 $$$— $32 
Capital expenditures579 264 624 — 1,467 
Reportable Segments
Ameren Illinois Electric DistributionAmeren Illinois
Natural Gas
Ameren Illinois TransmissionIntersegment EliminationsAmeren Illinois
2023
External revenues$2,218 $897 $367 $— $3,482 
Intersegment revenues— — 113 (113)— 
Revenue2,218 897 480 (113)3,482 
Purchased power(a)
(933)— — 113 (820)
Natural gas purchased for resale(a)
— (276)— — (276)
Other operations and maintenance expenses(a)
(532)(237)(49)— (818)
Other segment items
Depreciation and amortization(351)(108)(97)— (556)
Taxes other than income taxes(75)(67)(4)— (146)
Other income, net103 30 23 — 156 
Interest charges(89)(55)(60)— (204)
Income taxes(82)(50)(77)— (209)
Noncontrolling interests – preferred stock dividends(1)— (1)— (2)
Net income available to common shareholder$258 $134 $215 $— $607 
Interest income$19 $$$— $21 
Capital expenditures752 299 680 — 1,731 
(a)Significant segment expense that is regularly provided to the CODMs. Intersegment expenses are included within the amounts shown.
The following tables present disaggregated revenues by segment at Ameren and Ameren Illinois for the years ended December 31, 2025, 2024, and 2023. Economic factors affect the nature, timing, amount, and uncertainty of revenues and cash flows in a similar manner across customer classes. Revenues from alternative revenue programs have a similar distribution among customer classes as revenues from contracts with customers. Other revenues not associated with contracts with customers are presented in the Other customer classification, along with electric transmission and off-system sales and capacity revenues.
Ameren
Ameren MissouriAmeren Illinois Electric DistributionAmeren Illinois Natural GasAmeren TransmissionIntersegment EliminationsAmeren
2025
Residential$1,839 $1,483 $ $ $ $3,322 
Commercial1,450 785    2,235 
Industrial342 199    541 
Other1,000 (68) 862 (224)1,570 
Total electric revenues$4,631 $2,399 $ $862 $(224)$7,668 
Residential$101 $ $680 $ $ $781 
Commercial44  185   229 
Industrial5  12   17 
Other14  91  (1)104 
Total gas revenues$164 $ $968 $ $(1)$1,131 
Total revenues(a)
$4,795 $2,399 $968 $862 $(225)$8,799 
2024
Residential$1,638 $1,254 $— $— $— $2,892 
Commercial1,313 680 — — — 1,993 
Industrial311 178 — — — 489 
Other585 (23)— 781 (177)1,166 
Total electric revenues$3,847 $2,089 $— $781 $(177)$6,540 
Residential$90 $— $661 $— $— $751 
Commercial37 — 166 — — 203 
Industrial— 10 — — 14 
Other15 — 101 — (1)115 
Total gas revenues$146 $— $938 $— $(1)$1,083 
Total revenues(a)
$3,993 $2,089 $938 $781 $(178)$7,623 
2023
Residential$1,577 $1,344 $— $— $— $2,921 
Commercial1,280 747 — — — 2,027 
Industrial306 186 — — — 492 
Other531 (59)— 677 (150)999 
Total electric revenues$3,694 $2,218 $— $677 $(150)$6,439 
Residential$100 $— $657 $— $— $757 
Commercial46 — 164 — — 210 
Industrial— 14 — — 19 
Other14 — 62 — (1)75 
Total gas revenues$165 $— $897 $— $(1)$1,061 
Total revenues(a)
$3,859 $2,218 $897 $677 $(151)$7,500 
(a)The following table presents increases/(decreases) in revenues from alternative revenue programs and other revenues not from contracts with customers for the years ended December 31, 2025, 2024, and 2023:
Ameren MissouriAmeren Illinois Electric DistributionAmeren Illinois Natural GasAmeren TransmissionIntersegment EliminationsAmeren
2025
Revenues from alternative revenue programs$(5)$(135)$(34)$(26)$ $(200)
Other revenues not from contracts with customers6 
(a)
13 3  (4)18 
(a)
2024
Revenues from alternative revenue programs$$(43)$(3)$33 $— $(9)
Other revenues not from contracts with customers
(a)
10 — — 19 
(a)
2023
Revenues from alternative revenue programs$(5)$116 $49 $19 $— $179 
Other revenues not from contracts with customers(9)
(a)
— — — 
(a)
(a)Includes net realized gains and losses on derivative power contracts.
Ameren Illinois
Ameren Illinois Electric DistributionAmeren Illinois Natural GasAmeren Illinois TransmissionIntersegment EliminationsAmeren Illinois
2025
Residential$1,483 $680 $ $ $2,163 
Commercial785 185   970 
Industrial199 12   211 
Other(68)91 637 (160)500 
Total revenues(a)
$2,399 $968 $637 $(160)$3,844 
2024
Residential$1,254 $661 $— $— $1,915 
Commercial680 166 — — 846 
Industrial178 10 — — 188 
Other(23)101 564 (119)523 
Total revenues(a)
$2,089 $938 $564 $(119)$3,472 
2023
Residential$1,344 $657 $— $— $2,001 
Commercial747 164 — — 911 
Industrial186 14 — — 200 
Other(59)62 480 (113)370 
Total revenues(a)
$2,218 $897 $480 $(113)$3,482 
(a)The following table presents increases/(decreases) in revenues from alternative revenue programs and other revenues not from contracts with customers for the Ameren Illinois segments for the years ended December 31, 2025, 2024, and 2023:
Ameren Illinois Electric DistributionAmeren Illinois Natural GasAmeren Illinois TransmissionAmeren Illinois
2025
Revenues from alternative revenue programs$(135)$(34)$(19)$(188)
Other revenues not from contracts with customers13 3  16 
2024
Revenues from alternative revenue programs$(43)$(3)$29 $(17)
Other revenues not from contracts with customers10 — 12 
2023
Revenues from alternative revenue programs$116 $49 $12 $177 
Other revenues not from contracts with customers— 

Historical Timeline

Fiscal YearFiled
2025Feb 18, 2026Showing above
2024Feb 18, 2025
2023Feb 29, 2024
2022Feb 22, 2023
2021Feb 23, 2022
2020Feb 22, 2021
2019Feb 28, 2020
2018Feb 26, 2019
2017Feb 28, 2018

About Segments Disclosures

Segment disclosures break a company into its reportable operating units, revealing revenue, profit, and asset allocation that consolidated financial statements obscure. Under ASC 280, segments must match how the chief operating decision maker views the business, providing a window into internal management structure and resource allocation priorities.

Key signals: compare segment margins to identify which units drive profitability and which destroy value. Watch for changes in the number of reportable segments — segment aggregation or disaggregation often coincides with strategic shifts or attempts to obscure declining performance. Intersegment elimination patterns reveal internal pricing practices. The reconciliation between segment totals and consolidated figures exposes corporate overhead allocation and unallocated items. Geographic revenue concentration highlights regulatory and currency exposure. Compare segment-level capital expenditure against segment revenue to assess where management is investing for future growth versus harvesting existing assets.