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v3.25.4

Segment Information (Schedule Of Segment Reporting Information By Segment) (Details) $ in Millions | 12 Months Ended
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Dec. 31, 2025 USD ($) segment | Dec. 31, 2024 USD ($) | Dec. 31, 2023 USD ($)
Segment Reporting Information [Line Items] |  |  |
Number of reportable segments | segment | 4 |  |
External revenues | $ 8,799 | $ 7,623 | $ 7,500
Revenues | 8,799 | 7,623 | 7,500
Fuel and purchased power | (2,306) | (1,681) | (1,812)
Natural gas purchased for resale | (348) | (320) | (355)
Other operations and maintenance | (1,974) | (1,969) | (1,866)
Depreciation and amortization | (1,568) | (1,590) | (1,387)
Taxes other than income taxes | (577) | (547) | (522)
Other Income, Net | 347 | 417 | 348
Interest Charges | (776) | (663) | (566)
Income tax benefit | (136) | (83) | (183)
Preferred Stock Dividends | (5) | (5) | (5)
Net Income (Loss) Available to Common Stockholders, Basic | 1,456 | 1,182 | 1,152
Interest income | 41 | 41 | 33
Capital expenditures | $ 4,128 | 4,319 | 3,597
Ameren Missouri |  |  |
Segment Reporting Information [Line Items] |  |  |
Number of reportable segments | segment | 1 |  |
Ameren Illinois |  |  |
Segment Reporting Information [Line Items] |  |  |
Number of reportable segments | segment | 3 |  |
External revenues | $ 3,844 | 3,472 | 3,482
Revenues | 3,844 | 3,472 | 3,482
Purchased power | 781 | 621 | 820
Natural gas purchased for resale | (283) | (260) | (276)
Other operations and maintenance | (945) | (906) | (818)
Depreciation and amortization | (652) | (619) | (556)
Taxes other than income taxes | (169) | (157) | (146)
Other Income, Net | 136 | 147 | 156
Interest Charges | (260) | (241) | (204)
Income tax benefit | (153) | (193) | (209)
Preferred Stock Dividends | (2) | (2) | (2)
Net Income (Loss) Available to Common Stockholders, Basic | 735 | 620 | 607
Interest income | 32 | 32 | 21
Capital expenditures | 1,481 | 1,467 | 1,731
Operating Segments | Ameren Missouri |  |  |
Segment Reporting Information [Line Items] |  |  |
External revenues | 4,763 | 3,960 | 3,825
Revenues | 4,795 | 3,993 | 3,859
Fuel and purchased power | (1,538) | (1,071) | (997)
Natural gas purchased for resale | (65) | (60) | (79)
Other operations and maintenance | (1,029) | (1,050) | (1,003)
Depreciation and amortization | (860) | (917) | (783)
Taxes other than income taxes | (393) | (372) | (360)
Other Income, Net | 180 | 196 | 130
Interest Charges | (297) | (244) | (227)
Income tax benefit | (43) | 87 | 8
Preferred Stock Dividends | (3) | (3) | (3)
Net Income (Loss) Available to Common Stockholders, Basic | 747 | 559 | 545
Interest income | 9 | 8 | 11
Capital expenditures | 2,502 | 2,712 | 1,760
Operating Segments | Ameren Illinois Electric Distribution |  |  |
Segment Reporting Information [Line Items] |  |  |
External revenues | 2,393 | 2,088 | 2,217
Revenues | 2,399 | 2,089 | 2,218
Fuel and purchased power | (941) | (740) | (933)
Natural gas purchased for resale | 0 | 0 | 0
Other operations and maintenance | (656) | (619) | (532)
Depreciation and amortization | (373) | (369) | (351)
Taxes other than income taxes | (82) | (75) | (75)
Other Income, Net | 89 | 97 | 103
Interest Charges | (107) | (98) | (89)
Income tax benefit | (47) | (50) | (82)
Preferred Stock Dividends | (1) | (1) | (1)
Net Income (Loss) Available to Common Stockholders, Basic | 281 | 234 | 258
Interest income | 30 | 28 | 19
Capital expenditures | 635 | 579 | 752
Operating Segments | Ameren Illinois Gas |  |  |
Segment Reporting Information [Line Items] |  |  |
External revenues | 968 | 938 | 897
Revenues | 968 | 938 | 897
Fuel and purchased power | 0 | 0 | 0
Natural gas purchased for resale | (283) | (260) | (276)
Other operations and maintenance | (233) | (230) | (237)
Depreciation and amortization | (128) | (129) | (108)
Taxes other than income taxes | (82) | (78) | (67)
Other Income, Net | 19 | 27 | 30
Interest Charges | (65) | (63) | (55)
Income tax benefit | (38) | (56) | (50)
Preferred Stock Dividends | 0 | 0 | 0
Net Income (Loss) Available to Common Stockholders, Basic | 158 | 149 | 134
Interest income | 0 | 1 | 1
Capital expenditures | 283 | 264 | 299
Operating Segments | Ameren Transmission |  |  |
Segment Reporting Information [Line Items] |  |  |
External revenues | 675 | 637 | 561
Revenues | 862 | 781 | 677
Fuel and purchased power | 0 | 0 | 0
Natural gas purchased for resale | 0 | 0 | 0
Other operations and maintenance | (74) | (70) | (60)
Depreciation and amortization | (199) | (167) | (138)
Taxes other than income taxes | (9) | (9) | (8)
Other Income, Net | 24 | 26 | 28
Interest Charges | (120) | (117) | (96)
Income tax benefit | (68) | (120) | (106)
Preferred Stock Dividends | (1) | (1) | (1)
Net Income (Loss) Available to Common Stockholders, Basic | 415 | 323 | 296
Interest income | 3 | 6 | 2
Capital expenditures | 717 | 758 | 804
Operating Segments | Ameren Illinois | Ameren Illinois Electric Distribution |  |  |
Segment Reporting Information [Line Items] |  |  |
External revenues | 2,399 | 2,089 | 2,218
Revenues | 2,399 | 2,089 | 2,218
Purchased power | 941 | 740 | 933
Other operations and maintenance | (656) | (619) | (532)
Depreciation and amortization | (373) | (369) | (351)
Taxes other than income taxes | (82) | (75) | (75)
Other Income, Net | 89 | 97 | 103
Interest Charges | (107) | (98) | (89)
Income tax benefit | (47) | (50) | (82)
Preferred Stock Dividends | (1) | (1) | (1)
Net Income (Loss) Available to Common Stockholders, Basic | 281 | 234 | 258
Interest income | 30 | 28 | 19
Capital expenditures | 635 | 579 | 752
Operating Segments | Ameren Illinois | Ameren Illinois Gas |  |  |
Segment Reporting Information [Line Items] |  |  |
External revenues | 968 | 938 | 897
Revenues | 968 | 938 | 897
Natural gas purchased for resale | (283) | (260) | (276)
Other operations and maintenance | (233) | (230) | (237)
Depreciation and amortization | (128) | (129) | (108)
Taxes other than income taxes | (82) | (78) | (67)
Other Income, Net | 19 | 27 | 30
Interest Charges | (65) | (63) | (55)
Income tax benefit | (38) | (56) | (50)
Net Income (Loss) Available to Common Stockholders, Basic | 158 | 149 | 134
Interest income | 0 | 1 | 1
Capital expenditures | 283 | 264 | 299
Operating Segments | Ameren Illinois | Ameren Illinois Transmission |  |  |
Segment Reporting Information [Line Items] |  |  |
External revenues | 477 | 445 | 367
Revenues | 637 | 564 | 480
Other operations and maintenance | (56) | (57) | (49)
Depreciation and amortization | (151) | (121) | (97)
Taxes other than income taxes | (5) | (4) | (4)
Other Income, Net | 28 | 23 | 23
Interest Charges | (88) | (80) | (60)
Income tax benefit | (68) | (87) | (77)
Preferred Stock Dividends | (1) | (1) | (1)
Net Income (Loss) Available to Common Stockholders, Basic | 296 | 237 | 215
Interest income | 2 | 3 | 1
Capital expenditures | 563 | 624 | 680
Segment Reconciling Items |  |  |
Segment Reporting Information [Line Items] |  |  |
Other operations and maintenance | (34) | (48) | (67)
Depreciation and amortization | (8) | (8) | (7)
Taxes other than income taxes | (11) | (13) | (12)
Other Income, Net | 42 | 83 | 62
Interest Charges | (194) | (153) | (104)
Income tax benefit | 60 | 56 | 47
Net Income (Loss) Available to Common Stockholders, Basic | (145) | (83) | (81)
Interest income | 6 | 10 | 5
Capital expenditures | 8 | 7 | 9
Intersegment Elimination |  |  |
Segment Reporting Information [Line Items] |  |  |
Intersegment revenues | 225 | 178 | 151
Revenues | (225) | (178) | (151)
Fuel and purchased power | 173 | 130 | 118
Natural gas purchased for resale | 0 | 0 | 0
Other operations and maintenance | 52 | 48 | 33
Depreciation and amortization | 0 | 0 | 0
Taxes other than income taxes | 0 | 0 | 0
Other Income, Net | (7) | (12) | (5)
Interest Charges | 7 | 12 | 5
Income tax benefit | 0 | 0 | 0
Preferred Stock Dividends | 0 | 0 | 0
Interest income | (7) | (12) | (5)
Capital expenditures | (17) | (1) | (27)
Intersegment Elimination | Ameren Missouri |  |  |
Segment Reporting Information [Line Items] |  |  |
Intersegment revenues | 32 | 33 | 34
Intersegment Elimination | Ameren Illinois Electric Distribution |  |  |
Segment Reporting Information [Line Items] |  |  |
Intersegment revenues | 6 | 1 | 1
Intersegment Elimination | Ameren Illinois Gas |  |  |
Segment Reporting Information [Line Items] |  |  |
Intersegment revenues | 0 | 0 | 0
Intersegment Elimination | Ameren Transmission |  |  |
Segment Reporting Information [Line Items] |  |  |
Intersegment revenues | 187 | 144 | 116
Intersegment Elimination | Ameren Illinois |  |  |
Segment Reporting Information [Line Items] |  |  |
Intersegment revenues | 160 | 119 | 113
Revenues | (160) | (119) | (113)
Purchased power | 160 | 119 | 113
Intersegment Elimination | Ameren Illinois | Ameren Illinois Electric Distribution |  |  |
Segment Reporting Information [Line Items] |  |  |
Intersegment revenues | 0 | 0 | 0
Intersegment Elimination | Ameren Illinois | Ameren Illinois Gas |  |  |
Segment Reporting Information [Line Items] |  |  |
Intersegment revenues | 0 | 0 | 0
Intersegment Elimination | Ameren Illinois | Ameren Illinois Transmission |  |  |
Segment Reporting Information [Line Items] |  |  |
Intersegment revenues | $ 160 | $ 119 | $ 113

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