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Revenue (Disaggregation of Revenues) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | $ 1,081 | $ 1,077 | $ 3,005 | $ 3,066
Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 999 | 995 | 2,579 | 2,562
Electric [Member] | Retail - residential [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 378 | 374 | 966 | 943
Electric [Member] | Retail - commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 239 | 241 | 616 | 627
Electric [Member] | Retail - industrial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 270 | 280 | 730 | 740
Electric [Member] | Wholesale [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 58 | 59 | 147 | 154
Electric [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 54 | 41 | 120 | 98
Gas [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 49 | 47 | 322 | 400
Gas [Member] | Retail - residential [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 24 | 23 | 189 | 233
Gas [Member] | Retail - commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 13 | 12 | 92 | 122
Gas [Member] | Retail - industrial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 1 | 2 | 8 | 12
Gas [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 11 | 10 | 33 | 33
Other Utility [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 12 | 13 | 36 | 38
Other Utility [Member] | Steam [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 9 | 11 | 29 | 32
Other Utility [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 3 | 2 | 7 | 6
Non-utility and Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 21 | 22 | 68 | 66
Non-utility and Other [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 21 | 22 | 68 | 66
IPL [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 561 | 594 | 1,527 | 1,630
IPL [Member] | Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 523 | 551 | 1,318 | 1,370
IPL [Member] | Electric [Member] | Retail - residential [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 202 | 209 | 502 | 503
IPL [Member] | Electric [Member] | Retail - commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 153 | 158 | 385 | 399
IPL [Member] | Electric [Member] | Retail - industrial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 142 | 153 | 372 | 389
IPL [Member] | Electric [Member] | Wholesale [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 19 | 21 | 45 | 47
IPL [Member] | Electric [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 7 | 10 | 14 | 32
IPL [Member] | Gas [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 27 | 31 | 175 | 224
IPL [Member] | Gas [Member] | Retail - residential [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 13 | 14 | 103 | 131
IPL [Member] | Gas [Member] | Retail - commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 7 | 9 | 48 | 65
IPL [Member] | Gas [Member] | Retail - industrial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 1 | 2 | 5 | 8
IPL [Member] | Gas [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 6 | 6 | 19 | 20
IPL [Member] | Other Utility [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 11 | 12 | 34 | 36
IPL [Member] | Other Utility [Member] | Steam [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 9 | 11 | 29 | 32
IPL [Member] | Other Utility [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 2 | 1 | 5 | 4
WPL [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 499 | 461 | 1,410 | 1,370
WPL [Member] | Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 476 | 444 | 1,261 | 1,192
WPL [Member] | Electric [Member] | Retail - residential [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 176 | 165 | 464 | 440
WPL [Member] | Electric [Member] | Retail - commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 86 | 83 | 231 | 228
WPL [Member] | Electric [Member] | Retail - industrial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 128 | 127 | 358 | 351
WPL [Member] | Electric [Member] | Wholesale [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 39 | 38 | 102 | 107
WPL [Member] | Electric [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 47 | 31 | 106 | 66
WPL [Member] | Gas [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 22 | 16 | 147 | 176
WPL [Member] | Gas [Member] | Retail - residential [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 11 | 9 | 86 | 102
WPL [Member] | Gas [Member] | Retail - commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 6 | 3 | 44 | 57
WPL [Member] | Gas [Member] | Retail - industrial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 0 | 0 | 3 | 4
WPL [Member] | Gas [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 5 | 4 | 14 | 13
WPL [Member] | Other Utility [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 1 | 1 | 2 | 2
WPL [Member] | Other Utility [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | $ 1 | $ 1 | $ 2 | $ 2

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