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Segment Information | 12 Months Ended
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Dec. 31, 2025
Segment Reporting [Abstract] |
SEGMENT INFORMATION | 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 Missouri |  | Ameren Illinois Electric Distribution |  | Ameren Illinois Natural Gas |  | Ameren Transmission |  | Other |  | Intersegment Eliminations |  | Ameren |  |
2025 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
External revenues | $ | 4,763 |  |  | $ | 2,393 |  |  | $ | 968 |  |  | $ | 675 |  |  | $ | — |  |  | $ | — |  |  | $ | 8,799 |  |  |
Intersegment revenues | 32 |  |  | 6 |  |  | — |  |  | 187 |  |  | — |  |  | (225) |  |  | — |  |  |
Revenue | 4,795 |  |  | 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, net | 180 |  |  | 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 expenditures | 2,502 |  |  | 635 |  |  | 283 |  |  | 717 |  |  | 8 |  |  | (17) |  |  | 4,128 |  |  |
2024 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
External revenues | $ | 3,960 |  |  | $ | 2,088 |  |  | $ | 938 |  |  | $ | 637 |  |  | $ | — |  |  | $ | — |  |  | $ | 7,623 |  |  |
Intersegment revenues | 33 |  |  | 1 |  |  | — |  |  | 144 |  |  | — |  |  | (178) |  |  | — |  |  |
Revenue | 3,993 |  |  | 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, net | 196 |  |  | 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 | $ | 8 |  |  | $ | 28 |  |  | $ | 1 |  |  | $ | 6 |  |  | $ | 10 |  |  | $ | (12) |  |  | $ | 41 |  |  |
Capital expenditures | 2,712 |  |  | 579 |  |  | 264 |  |  | 758 |  |  | 7 |  |  | (1) |  |  | 4,319 |  |  |
| Reportable Segments |  |  |  |  |  |  |  |
| Ameren Missouri |  | Ameren Illinois Electric Distribution |  | Ameren Illinois Natural Gas |  | Ameren Transmission |  | Other |  | Intersegment Eliminations |  | Ameren |  |
2023 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
External revenues | $ | 3,825 |  |  | $ | 2,217 |  |  | $ | 897 |  |  | $ | 561 |  |  | $ | — |  |  | $ | — |  |  | $ | 7,500 |  |  |
Intersegment revenues | 34 |  |  | 1 |  |  | — |  |  | 116 |  |  | — |  |  | (151) |  |  | — |  |  |
Revenue | 3,859 |  |  | 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, net | 130 |  |  | 103 |  |  | 30 |  |  | 28 |  |  | 62 |  |  | (5) |  |  | 348 |  |  |
Interest charges | (227) |  |  | (89) |  |  | (55) |  |  | (96) |  | (b) | (104) |  |  | 5 |  |  | (566) |  |  |
Income taxes (benefit) | 8 |  |  | (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 |  |  | $ | 1 |  |  | $ | 2 |  |  | $ | 5 |  |  | $ | (5) |  |  | $ | 33 |  |  |
Capital expenditures | 1,760 |  |  | 752 |  |  | 299 |  |  | 804 |  |  | 9 |  |  | (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 Distribution |  | Ameren Illinois Natural Gas |  | Ameren Illinois Transmission |  | Intersegment Eliminations |  | Ameren Illinois |
2025 |  |  |  |  |  |  |  |  |  |
External revenues | $ | 2,399 |  |  | $ | 968 |  |  | $ | 477 |  |  | $ | — |  |  | $ | 3,844 |  |
Intersegment revenues | — |  |  | — |  |  | 160 |  |  | (160) |  |  | — |  |
Revenue | 2,399 |  |  | 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, net | 89 |  |  | 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 expenditures | 635 |  |  | 283 |  |  | 563 |  |  | — |  |  | 1,481 |  |
2024 |  |  |  |  |  |  |  |  |  |
External revenues | $ | 2,089 |  |  | $ | 938 |  |  | $ | 445 |  |  | $ | — |  |  | $ | 3,472 |  |
Intersegment revenues | — |  |  | — |  |  | 119 |  |  | (119) |  |  | — |  |
Revenue | 2,089 |  |  | 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, net | 97 |  |  | 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 |  |  | $ | 1 |  |  | $ | 3 |  |  | $ | — |  |  | $ | 32 |  |
Capital expenditures | 579 |  |  | 264 |  |  | 624 |  |  | — |  |  | 1,467 |  |
| Reportable Segments |  |  |  |  |
| Ameren Illinois Electric Distribution |  | Ameren Illinois Natural Gas |  | Ameren Illinois Transmission |  | Intersegment Eliminations |  | Ameren Illinois |
2023 |  |  |  |  |  |  |  |  |  |
External revenues | $ | 2,218 |  |  | $ | 897 |  |  | $ | 367 |  |  | $ | — |  |  | $ | 3,482 |  |
Intersegment revenues | — |  |  | — |  |  | 113 |  |  | (113) |  |  | — |  |
Revenue | 2,218 |  |  | 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, net | 103 |  |  | 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 |  |  | $ | 1 |  |  | $ | 1 |  |  | $ | — |  |  | $ | 21 |  |
Capital expenditures | 752 |  |  | 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 Missouri |  | Ameren Illinois Electric Distribution |  | Ameren Illinois Natural Gas |  | Ameren Transmission |  |  |  | Intersegment Eliminations |  | Ameren |
2025 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Residential | $ | 1,839 |  |  | $ | 1,483 |  |  | $ | — |  |  | $ | — |  |  |  |  | $ | — |  |  | $ | 3,322 |  |
Commercial | 1,450 |  |  | 785 |  |  | — |  |  | — |  |  |  |  | — |  |  | 2,235 |  |
Industrial | 342 |  |  | 199 |  |  | — |  |  | — |  |  |  |  | — |  |  | 541 |  |
Other | 1,000 |  |  | (68) |  |  | — |  |  | 862 |  |  |  |  | (224) |  |  | 1,570 |  |
Total electric revenues | $ | 4,631 |  |  | $ | 2,399 |  |  | $ | — |  |  | $ | 862 |  |  |  |  | $ | (224) |  |  | $ | 7,668 |  |
Residential | $ | 101 |  |  | $ | — |  |  | $ | 680 |  |  | $ | — |  |  |  |  | $ | — |  |  | $ | 781 |  |
Commercial | 44 |  |  | — |  |  | 185 |  |  | — |  |  |  |  | — |  |  | 229 |  |
Industrial | 5 |  |  | — |  |  | 12 |  |  | — |  |  |  |  | — |  |  | 17 |  |
Other | 14 |  |  | — |  |  | 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 |  |
Commercial | 1,313 |  |  | 680 |  |  | — |  |  | — |  |  |  |  | — |  |  | 1,993 |  |
Industrial | 311 |  |  | 178 |  |  | — |  |  | — |  |  |  |  | — |  |  | 489 |  |
Other | 585 |  |  | (23) |  |  | — |  |  | 781 |  |  |  |  | (177) |  |  | 1,166 |  |
Total electric revenues | $ | 3,847 |  |  | $ | 2,089 |  |  | $ | — |  |  | $ | 781 |  |  |  |  | $ | (177) |  |  | $ | 6,540 |  |
Residential | $ | 90 |  |  | $ | — |  |  | $ | 661 |  |  | $ | — |  |  |  |  | $ | — |  |  | $ | 751 |  |
Commercial | 37 |  |  | — |  |  | 166 |  |  | — |  |  |  |  | — |  |  | 203 |  |
Industrial | 4 |  |  | — |  |  | 10 |  |  | — |  |  |  |  | — |  |  | 14 |  |
Other | 15 |  |  | — |  |  | 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 |  |
Commercial | 1,280 |  |  | 747 |  |  | — |  |  | — |  |  |  |  | — |  |  | 2,027 |  |
Industrial | 306 |  |  | 186 |  |  | — |  |  | — |  |  |  |  | — |  |  | 492 |  |
Other | 531 |  |  | (59) |  |  | — |  |  | 677 |  |  |  |  | (150) |  |  | 999 |  |
Total electric revenues | $ | 3,694 |  |  | $ | 2,218 |  |  | $ | — |  |  | $ | 677 |  |  |  |  | $ | (150) |  |  | $ | 6,439 |  |
Residential | $ | 100 |  |  | $ | — |  |  | $ | 657 |  |  | $ | — |  |  |  |  | $ | — |  |  | $ | 757 |  |
Commercial | 46 |  |  | — |  |  | 164 |  |  | — |  |  |  |  | — |  |  | 210 |  |
Industrial | 5 |  |  | — |  |  | 14 |  |  | — |  |  |  |  | — |  |  | 19 |  |
Other | 14 |  |  | — |  |  | 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 Missouri |  | Ameren Illinois Electric Distribution |  | Ameren Illinois Natural Gas |  | Ameren Transmission |  | Intersegment Eliminations |  | Ameren |
2025 |  |  |  |  |  |  |  |  |  |  |  |
Revenues from alternative revenue programs | $ | (5) |  |  | $ | (135) |  |  | $ | (34) |  |  | $ | (26) |  |  | $ | — |  |  | $ | (200) |  |
Other revenues not from contracts with customers | 6 |  | (a) | 13 |  |  | 3 |  |  | — |  |  | (4) |  |  | 18 |  | (a)
2024 |  |  |  |  |  |  |  |  |  |  |  |
Revenues from alternative revenue programs | $ | 4 |  |  | $ | (43) |  |  | $ | (3) |  |  | $ | 33 |  |  | $ | — |  |  | $ | (9) |  |
Other revenues not from contracts with customers | 7 |  | (a) | 10 |  |  | 2 |  |  | — |  |  | — |  |  | 19 |  | (a)
2023 |  |  |  |  |  |  |  |  |  |  |  |
Revenues from alternative revenue programs | $ | (5) |  |  | $ | 116 |  |  | $ | 49 |  |  | $ | 19 |  |  | $ | — |  |  | $ | 179 |  |
Other revenues not from contracts with customers | (9) |  | (a) | 7 |  |  | 2 |  |  | — |  |  | — |  |  | — |  | (a)
(a)Includes net realized gains and losses on derivative power contracts. Ameren Illinois
| Ameren Illinois Electric Distribution |  | Ameren Illinois Natural Gas |  | Ameren Illinois Transmission |  | Intersegment Eliminations |  | Ameren Illinois |
2025 |  |  |  |  |  |  |  |  |  |
Residential | $ | 1,483 |  |  | $ | 680 |  |  | $ | — |  |  | $ | — |  |  | $ | 2,163 |  |
Commercial | 785 |  |  | 185 |  |  | — |  |  | — |  |  | 970 |  |
Industrial | 199 |  |  | 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 |  |
Commercial | 680 |  |  | 166 |  |  | — |  |  | — |  |  | 846 |  |
Industrial | 178 |  |  | 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 |  |
Commercial | 747 |  |  | 164 |  |  | — |  |  | — |  |  | 911 |  |
Industrial | 186 |  |  | 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 Distribution |  | Ameren Illinois Natural Gas |  | Ameren Illinois Transmission |  | Ameren Illinois
2025 |  |  |  |  |  |  |
Revenues from alternative revenue programs | $ | (135) |  |  | $ | (34) |  |  | $ | (19) |  |  | $ | (188) |
Other revenues not from contracts with customers | 13 |  |  | 3 |  |  | — |  |  | 16 |
2024 |  |  |  |  |  |  |
Revenues from alternative revenue programs | $ | (43) |  |  | $ | (3) |  |  | $ | 29 |  |  | $ | (17) |
Other revenues not from contracts with customers | 10 |  |  | 2 |  |  | — |  |  | 12 |
2023 |  |  |  |  |  |  |
Revenues from alternative revenue programs | $ | 116 |  |  | $ | 49 |  |  | $ | 12 |  |  | $ | 177 |
Other revenues not from contracts with customers | 7 |  |  | 2 |  |  | — |  |  | 9 |

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