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v3.22.2

Related Party Transactions (Effects of Related-party Transactions on the Statement of Income) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2022 | Jun. 30, 2021
Union Electric Company | Ameren Missouri Power Supply Agreements with Ameren Illinois |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | $ 1 | $ 3 | $ 5 | $ 5
Union Electric Company | Ameren Missouri and Ameren Illinois Rent and Facility Services |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | 6 | 7 | 12 | 14
Operating Expenses | 1 | 1 | 1 | 1
Union Electric Company | Ameren Missouri and Ameren Illinois Miscellaneous Support Services |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | 1 | 1 | 1 | 1
Union Electric Company | Total Related Party Operating Revenues |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | 7 | 10 | 17 | 19
Union Electric Company | Ameren Missouri and Ameren Illinois Transmission Services from ATXI |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Expenses | 1 | 1 | 1 | 2
Union Electric Company | Purchased Power |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Expenses | 1 | 1 | 1 | 2
Union Electric Company | Ameren Services Support Services Agreement |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Expenses | 33 | 34 | 71 | 69
Union Electric Company | Total Related Party Other Operations and Maintenance |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Expenses | 33 | 34 | 71 | 69
Union Electric Company | Money pool borrowings (advances) |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Interest Charges (Income) | 1 | 1 | 1 | 1
Ameren Illinois Company | Ameren Missouri and Ameren Illinois Rent and Facility Services |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | 1 | 1 | 1 | 1
Operating Expenses | 1 | 1 | 1 | 2
Ameren Illinois Company | Ameren Missouri and Ameren Illinois Miscellaneous Support Services |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | 1 | 2 | 1 | 2
Ameren Illinois Company | Total Related Party Operating Revenues |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Revenues | 1 | 2 | 1 | 2
Ameren Illinois Company | Ameren Illinois Power Supply Agreements with Ameren Missouri |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Expenses | 1 | 3 | 5 | 5
Ameren Illinois Company | Ameren Missouri and Ameren Illinois Transmission Services from ATXI |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Expenses | 1 | 1 | 1 | 1
Ameren Illinois Company | Purchased Power |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Expenses | 1 | 4 | 5 | 6
Ameren Illinois Company | Ameren Services Support Services Agreement |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Expenses | 32 | 31 | 67 | 64
Ameren Illinois Company | Total Related Party Other Operations and Maintenance |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Operating Expenses | 32 | 32 | 68 | 66
Ameren Illinois Company | Money pool borrowings (advances) |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Interest Charges (Income) | $ 1 | $ 1 | $ 1 | $ 1

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