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Regulatory Matters (Narrative) (Details) - USD ($) $ in Millions | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2020 | Mar. 31, 2019 | Dec. 31, 2020
2020 Forward Test Period Retail Electric [Member] | IPL [Member] |  |  |
Regulatory Matters [Line Items] |  |  |
Requested rate annual increase, amount |  | $ 204 |
Interim rate annual increase, amount |  | 90 |
2020 Forward Test Period Retail Gas [Member] | IPL [Member] |  |  |
Regulatory Matters [Line Items] |  |  |
Requested rate annual increase, amount |  | $ 21 |
Scenario, Forecast [Member] | 2020 Forward Test Period Retail Electric [Member] | IPL [Member] |  |  |
Regulatory Matters [Line Items] |  |  |
Requested rate annual increase, amount |  |  | $ 114
DAEC PPA [Member] |  |  |
Regulatory Matters [Line Items] |  |  |
PPA term amendment |  | 5 years |
Recovery period, authorized |  | 5 years |
DAEC PPA [Member] | Scenario, Forecast [Member] |  |  |
Regulatory Matters [Line Items] |  |  |
Buyout payment | $ 110 |  |

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- Definition Long-term Contract for Purchase of Electric Power, Buyout Payment + References No definition available. + Details
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- Definition Long-term Contract for Purchase of Electric Power, Contract Term Amendment + References No definition available. + Details
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- Definition Regulatory Matters [Line Items] + References No definition available. + Details
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- Definition Amount of public utility's interim rate increase (decrease) allowed while waiting final decision of regulatory agency. + References No definition available. + Details
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- Definition Amount of public utility's requested rate increase (decrease) with regulatory agency. + References No definition available. + Details
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- Definition Amortization period for the recovery of regulatory asset, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Details
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- Details
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- Details
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- Details
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- Details
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