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Preferred Stock (Narrative) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
Temporary Equity [Line Items] |  |  |  |
Redemption of IPL's cumulative preferred stock | $ 0 | $ 0 | $ 200 |
IPL [Member] |  |  |  |
Temporary Equity [Line Items] |  |  |  |
Redemption of IPL's cumulative preferred stock | $ 0 | $ 0 | 200 |
IPL [Member] | Cumulative Preferred Stock [Member] |  |  |  |
Temporary Equity [Line Items] |  |  |  |
Shares outstanding (in shares) |  |  |  | 8,000
Cumulative preferred stock rate |  |  |  | 5.10%
Preferred stock redemption price per share (in dollars per share) |  |  |  | $ 25
Redemption of IPL's cumulative preferred stock |  |  | 200 |
Non-cash charge, preferred stock redemption |  |  | $ 5 |

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