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v3.23.2

Segment Information (Disaggregation of Revenue) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2023 | Jun. 30, 2022 | Jun. 30, 2023 | Jun. 30, 2022
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | $ 1,760 | $ 1,726 | $ 3,822 | $ 3,605
Revenues | 1,760 | 1,726 | 3,822 | 3,605
Revenues from alternative revenue programs | 74 | 40 | 172 | 85
Other revenues not from contracts with customers | 1 | (34) | (2) | (31)
Union Electric Company |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues from alternative revenue programs | 0 | 0 | (2) | (6)
Other revenues not from contracts with customers | (2) | (36) | (8) | (36)
Ameren Illinois Electric Distribution |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues from alternative revenue programs | 60 | 41 | 124 | 96
Other revenues not from contracts with customers | 2 | 1 | 4 | 3
Ameren Illinois Natural Gas |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues from alternative revenue programs | 9 | 3 | 37 | (2)
Other revenues not from contracts with customers | 1 | 1 | 2 | 2
Ameren Transmission |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues from alternative revenue programs | 5 | (4) | 13 | (3)
Other revenues not from contracts with customers | 0 | 0 | 0 | 0
Electric |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 1,585 | 1,513 | 3,175 | 2,831
Revenues | 1,585 | 1,513 | 3,175 | 2,831
Electric | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 697 | 655 | 1,403 | 1,250
Electric | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 504 | 478 | 951 | 876
Electric | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 123 | 126 | 232 | 228
Electric | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 261 | 254 | 589 | 477
Natural gas |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 175 | 213 | 647 | 774
Revenues | 175 | 213 | 647 | 774
Natural gas | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 111 | 133 | 459 | 553
Natural gas | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 31 | 38 | 131 | 157
Natural gas | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 3 | 12 | 12 | 31
Natural gas | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 30 | 30 | 45 | 33
Ameren Illinois Company |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 779 | 769 | 1,880 | 1,793
Revenues | 779 | 769 | 1,880 | 1,793
Revenues from alternative revenue programs | 72 | 41 | 171 | 92
Other revenues not from contracts with customers | 3 | 2 | 6 | 5
Ameren Illinois Company | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 435 | 401 | 1,113 | 1,033
Ameren Illinois Company | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 218 | 210 | 495 | 465
Ameren Illinois Company | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 50 | 64 | 105 | 126
Ameren Illinois Company | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 76 | 94 | 167 | 169
Ameren Illinois Company | Ameren Illinois Electric Distribution |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues from alternative revenue programs | 60 | 41 | 124 | 96
Other revenues not from contracts with customers | 2 | 1 | 4 | 3
Ameren Illinois Company | Ameren Illinois Natural Gas |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues from alternative revenue programs | 9 | 3 | 37 | (2)
Other revenues not from contracts with customers | 1 | 1 | 2 | 2
Ameren Illinois Company | Ameren Illinois Transmission |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues from alternative revenue programs | 3 | (3) | 10 | (2)
Other revenues not from contracts with customers | 0 | 0 | 0 | 0
Ameren Illinois Company | Electric |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 627 | 585 | 1,337 | 1,128
Ameren Illinois Company | Natural gas |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 152 | 184 | 543 | 665
Operating Segments | Union Electric Company |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 933 | 912 | 1,846 | 1,720
Revenues | 941 | 919 | 1,864 | 1,737
Operating Segments | Ameren Illinois Electric Distribution |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 540 | 504 | 1,164 | 968
Revenues | 540 | 504 | 1,164 | 969
Operating Segments | Ameren Illinois Natural Gas |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 152 | 184 | 543 | 665
Revenues | 152 | 184 | 543 | 665
Operating Segments | Ameren Transmission |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 135 | 126 | 269 | 252
Revenues | 161 | 150 | 324 | 296
Operating Segments | Electric | Union Electric Company |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 918 | 890 | 1,759 | 1,628
Operating Segments | Electric | Union Electric Company | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 360 | 371 | 684 | 703
Operating Segments | Electric | Union Electric Company | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 311 | 298 | 558 | 538
Operating Segments | Electric | Union Electric Company | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 75 | 73 | 136 | 130
Operating Segments | Electric | Union Electric Company | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 172 | 148 | 381 | 257
Operating Segments | Electric | Ameren Illinois Electric Distribution |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 540 | 504 | 1,164 | 969
Operating Segments | Electric | Ameren Illinois Electric Distribution | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 337 | 284 | 719 | 547
Operating Segments | Electric | Ameren Illinois Electric Distribution | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 193 | 180 | 393 | 338
Operating Segments | Electric | Ameren Illinois Electric Distribution | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 48 | 53 | 96 | 98
Operating Segments | Electric | Ameren Illinois Electric Distribution | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | (38) | (13) | (44) | (14)
Operating Segments | Electric | Ameren Illinois Natural Gas |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | 0 | 0
Operating Segments | Electric | Ameren Illinois Natural Gas | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Operating Segments | Electric | Ameren Illinois Natural Gas | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Operating Segments | Electric | Ameren Illinois Natural Gas | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Operating Segments | Electric | Ameren Illinois Natural Gas | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | 0 | 0
Operating Segments | Electric | Ameren Transmission |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 161 | 150 | 324 | 296
Operating Segments | Electric | Ameren Transmission | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Operating Segments | Electric | Ameren Transmission | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Operating Segments | Electric | Ameren Transmission | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Operating Segments | Electric | Ameren Transmission | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 161 | 150 | 324 | 296
Operating Segments | Natural gas | Union Electric Company |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 23 | 29 | 105 | 109
Operating Segments | Natural gas | Union Electric Company | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 13 | 16 | 65 | 67
Operating Segments | Natural gas | Union Electric Company | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 6 | 8 | 29 | 30
Operating Segments | Natural gas | Union Electric Company | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 1 | 1 | 3 | 3
Operating Segments | Natural gas | Union Electric Company | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 3 | 4 | 8 | 9
Operating Segments | Natural gas | Ameren Illinois Electric Distribution |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | 0 | 0
Operating Segments | Natural gas | Ameren Illinois Electric Distribution | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Operating Segments | Natural gas | Ameren Illinois Electric Distribution | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Operating Segments | Natural gas | Ameren Illinois Electric Distribution | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Operating Segments | Natural gas | Ameren Illinois Electric Distribution | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | 0 | 0
Operating Segments | Natural gas | Ameren Illinois Natural Gas |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 152 | 184 | 543 | 665
Operating Segments | Natural gas | Ameren Illinois Natural Gas | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 98 | 117 | 394 | 486
Operating Segments | Natural gas | Ameren Illinois Natural Gas | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 25 | 30 | 102 | 127
Operating Segments | Natural gas | Ameren Illinois Natural Gas | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 2 | 11 | 9 | 28
Operating Segments | Natural gas | Ameren Illinois Natural Gas | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 27 | 26 | 38 | 24
Operating Segments | Natural gas | Ameren Transmission |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | 0 | 0
Operating Segments | Natural gas | Ameren Transmission | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Operating Segments | Natural gas | Ameren Transmission | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Operating Segments | Natural gas | Ameren Transmission | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Operating Segments | Natural gas | Ameren Transmission | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | 0 | 0
Operating Segments | Ameren Illinois Company | Ameren Illinois Electric Distribution |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 540 | 504 | 1,164 | 969
Operating Segments | Ameren Illinois Company | Ameren Illinois Natural Gas |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 152 | 184 | 543 | 665
Operating Segments | Ameren Illinois Company | Ameren Illinois Transmission |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 87 | 81 | 173 | 159
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Electric Distribution |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 540 | 504 | 1,164 | 969
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Electric Distribution | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 337 | 284 | 719 | 547
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Electric Distribution | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 193 | 180 | 393 | 338
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Electric Distribution | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 48 | 53 | 96 | 98
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Electric Distribution | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | (38) | (13) | (44) | (14)
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Transmission |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 113 | 105 | 227 | 203
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Transmission | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Transmission | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Transmission | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Operating Segments | Ameren Illinois Company | Electric | Ameren Illinois Transmission | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 113 | 105 | 227 | 203
Operating Segments | Ameren Illinois Company | Natural gas | Ameren Illinois Natural Gas |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 152 | 184 | 543 | 665
Operating Segments | Ameren Illinois Company | Natural gas | Ameren Illinois Natural Gas | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 98 | 117 | 394 | 486
Operating Segments | Ameren Illinois Company | Natural gas | Ameren Illinois Natural Gas | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 25 | 30 | 102 | 127
Operating Segments | Ameren Illinois Company | Natural gas | Ameren Illinois Natural Gas | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 2 | 11 | 9 | 28
Operating Segments | Ameren Illinois Company | Natural gas | Ameren Illinois Natural Gas | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 27 | 26 | 38 | 24
Intersegment Eliminations |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | (34) | (31) | (73) | (62)
Revenues | (34) | (31) | (73) | (62)
Intersegment Eliminations | Union Electric Company |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | (8) | (7) | (18) | (17)
Intersegment Eliminations | Ameren Illinois Electric Distribution |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | 0 | (1)
Intersegment Eliminations | Ameren Illinois Natural Gas |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Ameren Transmission |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | (26) | (24) | (55) | (44)
Intersegment Eliminations | Electric |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | (34) | (31) | (72) | (62)
Intersegment Eliminations | Electric | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Electric | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Electric | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Electric | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | (34) | (31) | (72) | (62)
Intersegment Eliminations | Natural gas |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | (1) | 0
Intersegment Eliminations | Natural gas | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Natural gas | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Natural gas | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Natural gas | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | (1) | 0
Intersegment Eliminations | Ameren Illinois Company |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | (26) | (24) | (54) | (44)
Revenues | (26) | (24) | (54) | (44)
Intersegment Eliminations | Ameren Illinois Company | Residential |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Ameren Illinois Company | Commercial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Ameren Illinois Company | Industrial |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Operating Revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Ameren Illinois Company | Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | (26) | (24) | (54) | (44)
Intersegment Eliminations | Ameren Illinois Company | Ameren Illinois Electric Distribution |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Ameren Illinois Company | Ameren Illinois Natural Gas |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 0 | 0 | 0 | 0
Intersegment Eliminations | Ameren Illinois Company | Ameren Illinois Transmission |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | $ (26) | $ (24) | $ (54) | $ (44)

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