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Property and Plant, Net (Schedule of Capitalized Software, Future Amortization Expense) (Details) - Capitalized software costs $ in Millions | Dec. 31, 2024 USD ($)
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Finite-Lived Intangible Assets [Line Items] |
2025 | $ 190
2026 | 147
2027 | 110
2028 | 69
2029 | 38
Ameren Missouri |
Finite-Lived Intangible Assets [Line Items] |
2025 | 98
2026 | 73
2027 | 54
2028 | 33
2029 | 17
Ameren Illinois |
Finite-Lived Intangible Assets [Line Items] |
2025 | 85
2026 | 70
2027 | 53
2028 | 34
2029 | $ 20

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