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Revenue (Disaggregation of Revenues) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2023 | Jun. 30, 2022 | Jun. 30, 2023 | Jun. 30, 2022
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | $ 912 | $ 943 | $ 1,990 | $ 2,012
Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 799 | 812 | 1,567 | 1,586
Electric [Member] | Retail - residential [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 284 | 289 | 569 | 581
Electric [Member] | Retail - commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 201 | 196 | 385 | 386
Electric [Member] | Retail - industrial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 245 | 244 | 460 | 453
Electric [Member] | Wholesale [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 49 | 54 | 95 | 101
Electric [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 20 | 29 | 58 | 65
Gas [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 77 | 94 | 353 | 356
Gas [Member] | Retail - residential [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 42 | 51 | 210 | 210
Gas [Member] | Retail - commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 22 | 27 | 110 | 109
Gas [Member] | Retail - industrial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 3 | 3 | 9 | 11
Gas [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 10 | 13 | 24 | 26
Other Utility [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 13 | 13 | 25 | 23
Other Utility [Member] | Steam [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 11 | 11 | 22 | 20
Other Utility [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 2 | 2 | 3 | 3
Non-utility and Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 23 | 24 | 45 | 47
Non-utility and Other [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 23 | 24 | 45 | 47
IPL [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 487 | 506 | 1,037 | 1,056
IPL [Member] | Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 431 | 442 | 819 | 843
IPL [Member] | Electric [Member] | Retail - residential [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 151 | 158 | 294 | 308
IPL [Member] | Electric [Member] | Retail - commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 129 | 127 | 241 | 246
IPL [Member] | Electric [Member] | Retail - industrial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 130 | 136 | 236 | 246
IPL [Member] | Electric [Member] | Wholesale [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 14 | 16 | 26 | 31
IPL [Member] | Electric [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 7 | 5 | 22 | 12
IPL [Member] | Gas [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 44 | 52 | 194 | 191
IPL [Member] | Gas [Member] | Retail - residential [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 24 | 28 | 117 | 113
IPL [Member] | Gas [Member] | Retail - commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 12 | 14 | 56 | 54
IPL [Member] | Gas [Member] | Retail - industrial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 2 | 2 | 6 | 7
IPL [Member] | Gas [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 6 | 8 | 15 | 17
IPL [Member] | Other Utility [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 12 | 12 | 24 | 22
IPL [Member] | Other Utility [Member] | Steam [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 11 | 11 | 22 | 20
IPL [Member] | Other Utility [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 1 | 1 | 2 | 2
WPL [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 402 | 413 | 908 | 909
WPL [Member] | Electric [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 368 | 370 | 748 | 743
WPL [Member] | Electric [Member] | Retail - residential [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 133 | 131 | 275 | 273
WPL [Member] | Electric [Member] | Retail - commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 72 | 69 | 144 | 140
WPL [Member] | Electric [Member] | Retail - industrial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 115 | 108 | 224 | 207
WPL [Member] | Electric [Member] | Wholesale [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 35 | 38 | 69 | 70
WPL [Member] | Electric [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 13 | 24 | 36 | 53
WPL [Member] | Gas [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 33 | 42 | 159 | 165
WPL [Member] | Gas [Member] | Retail - residential [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 18 | 23 | 93 | 97
WPL [Member] | Gas [Member] | Retail - commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 10 | 13 | 54 | 55
WPL [Member] | Gas [Member] | Retail - industrial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 1 | 1 | 3 | 4
WPL [Member] | Gas [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 4 | 5 | 9 | 9
WPL [Member] | Other Utility [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | 1 | 1 | 1 | 1
WPL [Member] | Other Utility [Member] | Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contracts with customers | $ 1 | $ 1 | $ 1 | $ 1

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