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Segment Information (Schedule Of Segment Reporting Information By Segment) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023
Segment Reporting Information [Line Items] |  |  |  |
Operating Revenues | $ 1,693 | $ 1,760 | $ 3,509 | $ 3,822
Net income (loss) attributable to common shareholders | 258 | 237 | 519 | 501
Capital expenditures | 1,002 | 891 | 1,892 | 1,822
Union Electric Company |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating Revenues | 888 | 941 | 1,663 | 1,864
Net Income (Loss) | 128 | 102 | 153 | 130
Ameren Illinois Company |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating Revenues | 766 | 779 | 1,766 | 1,880
Net Income (Loss) | 124 | 129 | 339 | 327
Capital expenditures | 344 | 437 | 717 | 844
Operating Segments | Union Electric Company |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating Revenues | 879 | 933 | 1,647 | 1,846
Net Income (Loss) | 128 | 102 | 153 | 130
Capital expenditures | 638 | 433 | 1,104 | 914
Operating Segments | Ameren Illinois Electric Distribution |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating Revenues | 509 | 540 | 1,015 | 1,164
Net Income (Loss) | 61 | 66 | 117 | 127
Capital expenditures | 132 | 180 | 316 | 350
Operating Segments | Ameren Illinois Natural Gas |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating Revenues | 148 | 152 | 539 | 543
Net Income (Loss) | 6 | 11 | 112 | 98
Capital expenditures | 59 | 90 | 119 | 141
Operating Segments | Ameren Transmission |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating Revenues | 157 | 135 | 308 | 269
Net Income (Loss) | 79 | 72 | 151 | 143
Capital expenditures | 175 | 197 | 341 | 410
Operating Segments | Ameren Illinois Company | Ameren Illinois Electric Distribution |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating Revenues | 509 | 540 | 1,015 | 1,164
Net Income (Loss) | 61 | 66 | 117 | 127
Capital expenditures | 132 | 180 | 316 | 350
Operating Segments | Ameren Illinois Company | Ameren Illinois Natural Gas |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating Revenues | 148 | 152 | 539 | 543
Net Income (Loss) | 6 | 11 | 112 | 98
Capital expenditures | 59 | 90 | 119 | 141
Operating Segments | Ameren Illinois Company | Ameren Illinois Transmission |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating Revenues | 109 | 87 | 212 | 173
Net Income (Loss) | 57 | 52 | 110 | 102
Capital expenditures | 153 | 167 | 282 | 353
Other |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Income (Loss) | (16) | (14) | (14) | 3
Capital expenditures | 2 | 2 | 4 | 5
Intersegment Eliminations |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Intersegment revenues | (43) | (34) | (84) | (73)
Capital expenditures | (4) | (11) | 8 | 2
Intersegment Eliminations | Union Electric Company |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Intersegment revenues | (9) | (8) | (16) | (18)
Intersegment Eliminations | Ameren Illinois Electric Distribution |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Intersegment revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Ameren Illinois Natural Gas |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Intersegment revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Ameren Transmission |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Intersegment revenues | (34) | (26) | (68) | (55)
Intersegment Eliminations | Ameren Illinois Company |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Intersegment revenues | (27) | (26) | (55) | (54)
Intersegment Eliminations | Ameren Illinois Company | Ameren Illinois Electric Distribution |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Intersegment revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Ameren Illinois Company | Ameren Illinois Natural Gas |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Intersegment revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Ameren Illinois Company | Ameren Illinois Transmission |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Intersegment revenues | $ (27) | $ (26) | $ (55) | $ (54)

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