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Segment Information (Schedule Of Segment Reporting Information By Segment) (Details) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 USD ($) segment | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
Segment Reporting Information [Line Items] |  |  |
Number of reportable segments | segment | 4 |  |
External revenues | $ 7,623 | $ 7,500 | $ 7,957
Revenues | 7,623 | 7,500 | 7,957
Fuel 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)
Other Income, Net | 417 | 348 | 226
Interest Charges | (663) | (566) | (486)
Income tax benefit | (83) | (183) | (176)
Preferred Stock Dividends | (5) | (5) | (5)
Net Income (Loss) Available to Common Stockholders, Basic | 1,182 | 1,152 | 1,074
Interest income | 41 | 33 | 35
Capital expenditures | $ 4,319 | 3,597 | 3,351
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 | $ 3,472 | 3,482 | 3,756
Revenues | 3,472 | 3,482 | 3,756
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)
Other Income, Net | 147 | 156 | 96
Interest Charges | (241) | (204) | (168)
Income tax benefit | (193) | (209) | (179)
Preferred Stock Dividends | (2) | (2) | (2)
Net Income (Loss) Available to Common Stockholders, Basic | 620 | 607 | 513
Interest income | 32 | 21 | 7
Capital expenditures | 1,467 | 1,731 | 1,601
Operating Segments | Ameren Missouri |  |  |
Segment Reporting Information [Line Items] |  |  |
External revenues | 3,960 | 3,825 | 4,012
Revenues | 3,993 | 3,859 | 4,046
Fuel 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)
Other Income, Net | 196 | 130 | 99
Interest Charges | (244) | (227) | (213)
Income tax benefit | 87 | 8 | 10
Preferred Stock Dividends | (3) | (3) | (3)
Net Income (Loss) Available to Common Stockholders, Basic | 559 | 545 | 562
Interest income | 8 | 11 | 28
Capital expenditures | 2,712 | 1,760 | 1,690
Operating Segments | Ameren Illinois Electric Distribution |  |  |
Segment Reporting Information [Line Items] |  |  |
External revenues | 2,088 | 2,217 | 2,255
Revenues | 2,089 | 2,218 | 2,256
Fuel and purchased power | (740) | (933) | (984)
Natural gas purchased for resale | 0 | 0 | 0
Other operations and maintenance | (619) | (532) | (580)
Depreciation and amortization | (369) | (351) | (332)
Taxes other than income taxes | (75) | (75) | (75)
Other Income, Net | 97 | 103 | 60
Interest Charges | (98) | (89) | (74)
Income tax benefit | (50) | (82) | (68)
Preferred Stock Dividends | (1) | (1) | (1)
Net Income (Loss) Available to Common Stockholders, Basic | 234 | 258 | 202
Interest income | 28 | 19 | 7
Capital expenditures | 579 | 752 | 621
Operating Segments | Ameren Illinois Gas |  |  |
Segment Reporting Information [Line Items] |  |  |
External revenues | 938 | 897 | 1,180
Revenues | 938 | 897 | 1,180
Fuel and purchased power | 0 | 0 | 0
Natural gas purchased for resale | (260) | (276) | (553)
Other operations and maintenance | (230) | (237) | (253)
Depreciation and amortization | (129) | (108) | (98)
Taxes other than income taxes | (78) | (67) | (82)
Other Income, Net | 27 | 30 | 19
Interest Charges | (63) | (55) | (44)
Income tax benefit | (56) | (50) | (46)
Preferred Stock Dividends | 0 | 0 | 0
Net Income (Loss) Available to Common Stockholders, Basic | 149 | 134 | 123
Interest income | 1 | 1 | 0
Capital expenditures | 264 | 299 | 308
Operating Segments | Ameren Transmission |  |  |
Segment Reporting Information [Line Items] |  |  |
External revenues | 637 | 561 | 510
Revenues | 781 | 677 | 615
Fuel and purchased power | 0 | 0 | 0
Natural gas purchased for resale | 0 | 0 | 0
Other operations and maintenance | (70) | (60) | (60)
Depreciation and amortization | (167) | (138) | (123)
Taxes other than income taxes | (9) | (8) | (9)
Other Income, Net | 26 | 28 | 17
Interest Charges | (117) | (96) | (84)
Income tax benefit | (120) | (106) | (92)
Preferred Stock Dividends | (1) | (1) | (1)
Net Income (Loss) Available to Common Stockholders, Basic | 323 | 296 | 263
Interest income | 6 | 2 | 0
Capital expenditures | 758 | 804 | 741
Operating Segments | Ameren Illinois | Ameren Illinois Electric Distribution |  |  |
Segment Reporting Information [Line Items] |  |  |
External revenues | 2,089 | 2,218 | 2,256
Revenues | 2,089 | 2,218 | 2,256
Purchased power | 740 | 933 | 984
Other operations and maintenance | (619) | (532) | (580)
Depreciation and amortization | (369) | (351) | (332)
Taxes other than income taxes | (75) | (75) | (75)
Other Income, Net | 97 | 103 | 60
Interest Charges | (98) | (89) | (74)
Income tax benefit | (50) | (82) | (68)
Preferred Stock Dividends | (1) | (1) | (1)
Net Income (Loss) Available to Common Stockholders, Basic | 234 | 258 | 202
Interest income | 28 | 19 | 7
Capital expenditures | 579 | 752 | 621
Operating Segments | Ameren Illinois | Ameren Illinois Gas |  |  |
Segment Reporting Information [Line Items] |  |  |
External revenues | 938 | 897 | 1,180
Revenues | 938 | 897 | 1,180
Natural gas purchased for resale | (260) | (276) | (553)
Other operations and maintenance | (230) | (237) | (253)
Depreciation and amortization | (129) | (108) | (98)
Taxes other than income taxes | (78) | (67) | (82)
Other Income, Net | 27 | 30 | 19
Interest Charges | (63) | (55) | (44)
Income tax benefit | (56) | (50) | (46)
Net Income (Loss) Available to Common Stockholders, Basic | 149 | 134 | 123
Interest income | 1 | 1 | 0
Capital expenditures | 264 | 299 | 308
Operating Segments | Ameren Illinois | Ameren Illinois Transmission |  |  |
Segment Reporting Information [Line Items] |  |  |
External revenues | 445 | 367 | 320
Revenues | 564 | 480 | 424
Other operations and maintenance | (57) | (49) | (49)
Depreciation and amortization | (121) | (97) | (84)
Taxes other than income taxes | (4) | (4) | (4)
Other Income, Net | 23 | 23 | 17
Interest Charges | (80) | (60) | (50)
Income tax benefit | (87) | (77) | (65)
Preferred Stock Dividends | (1) | (1) | (1)
Net Income (Loss) Available to Common Stockholders, Basic | 237 | 215 | 188
Interest income | 3 | 1 | 0
Capital expenditures | 624 | 680 | 672
Segment Reconciling Items |  |  |
Segment Reporting Information [Line Items] |  |  |
Other operations and maintenance | (48) | (67) | (42)
Depreciation and amortization | (8) | (7) | (4)
Taxes other than income taxes | (13) | (12) | (10)
Other Income, Net | 83 | 62 | 32
Interest Charges | (153) | (104) | (72)
Income tax benefit | 56 | 47 | 20
Net Income (Loss) Available to Common Stockholders, Basic | (83) | (81) | (76)
Interest income | 10 | 5 | 1
Capital expenditures | 7 | 9 | 7
Intersegment Elimination |  |  |
Segment Reporting Information [Line Items] |  |  |
Intersegment revenues | 178 | 151 | 140
Revenues | (178) | (151) | (140)
Fuel and purchased power | 130 | 118 | 114
Natural gas purchased for resale | 0 | 0 | 0
Other operations and maintenance | 48 | 33 | 26
Depreciation and amortization | 0 | 0 | 0
Taxes other than income taxes | 0 | 0 | 0
Other Income, Net | (12) | (5) | (1)
Interest Charges | 12 | 5 | 1
Income tax benefit | 0 | 0 | 0
Preferred Stock Dividends | 0 | 0 | 0
Interest income | (12) | (5) | (1)
Capital expenditures | (1) | (27) | (16)
Intersegment Elimination | Ameren Missouri |  |  |
Segment Reporting Information [Line Items] |  |  |
Intersegment revenues | 33 | 34 | 34
Intersegment Elimination | Ameren Illinois Electric Distribution |  |  |
Segment Reporting Information [Line Items] |  |  |
Intersegment revenues | 1 | 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 | 144 | 116 | 105
Intersegment Elimination | Ameren Illinois |  |  |
Segment Reporting Information [Line Items] |  |  |
Intersegment revenues | 119 | 113 | 104
Revenues | (119) | (113) | (104)
Purchased power | 119 | 113 | 104
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 | $ 119 | $ 113 | $ 104

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