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v3.23.3

Related Party Transactions (Effects of Related-party Transactions on the Statement of Income) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2023 | Sep. 30, 2022
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | $ 2,060 | $ 2,306 | $ 5,882 | $ 5,911
Purchased Power | 272 | 563 | 1,095 | 1,058
Other operations and maintenance | 470 | 475 | 1,368 | 1,427
(Interest Charges)/Other Income, Net | 152 | 126 | 413 | 356
Union Electric Company |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | 1,237 | 1,359 | 3,101 | 3,096
Purchased Power | 75 | 247 | 420 | 458
Other operations and maintenance | 256 | 252 | 732 | 744
(Interest Charges)/Other Income, Net | 63 | 58 | 166 | 157
Union Electric Company | Ameren Missouri Power Supply Agreements with Ameren Illinois | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | 2 | 2 | 2 | 7
Union Electric Company | Ameren Missouri and Ameren Illinois Rent and Facility Services | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | 7 | 6 | 25 | 18
Other operations and maintenance | 1 | 1 | 1 | 1
Union Electric Company | Ameren Missouri and Ameren Illinois Miscellaneous Support Services | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | 1 | 1 | 1 | 1
Union Electric Company | Total Related Party Operating Revenues | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | 9 | 8 | 27 | 25
Union Electric Company | Ameren Missouri and Ameren Illinois Transmission Services from ATXI | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Purchased Power | 1 | 1 | 1 | 1
Union Electric Company | Purchased Power | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Purchased Power | 1 | 1 | 1 | 1
Union Electric Company | Ameren Services Support Services Agreement | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Other operations and maintenance | 36 | 38 | 106 | 109
Union Electric Company | Total Related Party Other Operations and Maintenance | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Other operations and maintenance | 36 | 38 | 106 | 109
Union Electric Company | Money pool borrowings (advances) | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
(Interest Charges)/Other Income, Net | 1 | 1 |  | 1
Ameren Illinois Company |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | 783 | 904 | 2,663 | 2,697
Purchased Power | 200 | 319 | 679 | 608
Other operations and maintenance | 200 | 215 | 603 | 663
(Interest Charges)/Other Income, Net | 54 | 42 | 151 | 125
Ameren Illinois Company | Ameren Missouri and Ameren Illinois Rent and Facility Services | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | 1 | 1 | 1 | 1
Other operations and maintenance | 1 | 1 | 2 | 2
Ameren Illinois Company | Ameren Missouri and Ameren Illinois Miscellaneous Support Services | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | 2 | 1 | 2 | 1
Ameren Illinois Company | Total Related Party Operating Revenues | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | 2 | 1 | 2 | 1
Ameren Illinois Company | Ameren Illinois Power Supply Agreements with Ameren Missouri | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Purchased Power | 2 | 2 | 2 | 7
Ameren Illinois Company | Ameren Missouri and Ameren Illinois Transmission Services from ATXI | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Purchased Power | 1 | 1 | 1 | 1
Ameren Illinois Company | Purchased Power | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Purchased Power | 3 | 2 | 3 | 7
Ameren Illinois Company | Ameren Services Support Services Agreement | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Other operations and maintenance | 33 | 36 | 101 | 103
Ameren Illinois Company | Total Related Party Other Operations and Maintenance | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Other operations and maintenance | 33 | 37 | 103 | 105
Ameren Illinois Company | Money pool borrowings (advances) | Related Party |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
(Interest Charges)/Other Income, Net | $ 1 | $ 1 | $ 1 | $ 1

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