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Revenue (Disaggregation of Revenues) (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2023 | Mar. 31, 2022
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | $ 1,077 | $ 1,068
Electric [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 768 | 773
Electric [Member] | Retail - residential [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 285 | 293
Electric [Member] | Retail - commercial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 185 | 188
Electric [Member] | Retail - industrial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 216 | 211
Electric [Member] | Wholesale [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 46 | 47
Electric [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 36 | 34
Gas [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 276 | 262
Gas [Member] | Retail - residential [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 167 | 158
Gas [Member] | Retail - commercial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 88 | 82
Gas [Member] | Retail - industrial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 7 | 8
Gas [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 14 | 14
Other Utility [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 11 | 11
Other Utility [Member] | Steam [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 10 | 9
Other Utility [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 1 | 2
Non-utility and Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 22 | 22
Non-utility and Other [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 22 | 22
IPL [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 549 | 550
IPL [Member] | Electric [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 388 | 400
IPL [Member] | Electric [Member] | Retail - residential [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 143 | 150
IPL [Member] | Electric [Member] | Retail - commercial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 112 | 118
IPL [Member] | Electric [Member] | Retail - industrial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 107 | 111
IPL [Member] | Electric [Member] | Wholesale [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 12 | 15
IPL [Member] | Electric [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 14 | 6
IPL [Member] | Gas [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 150 | 139
IPL [Member] | Gas [Member] | Retail - residential [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 93 | 85
IPL [Member] | Gas [Member] | Retail - commercial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 44 | 40
IPL [Member] | Gas [Member] | Retail - industrial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 4 | 5
IPL [Member] | Gas [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 9 | 9
IPL [Member] | Other Utility [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 11 | 11
IPL [Member] | Other Utility [Member] | Steam [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 10 | 9
IPL [Member] | Other Utility [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 1 | 2
WPL [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 506 | 496
WPL [Member] | Electric [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 380 | 373
WPL [Member] | Electric [Member] | Retail - residential [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 142 | 143
WPL [Member] | Electric [Member] | Retail - commercial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 73 | 70
WPL [Member] | Electric [Member] | Retail - industrial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 109 | 100
WPL [Member] | Electric [Member] | Wholesale [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 34 | 32
WPL [Member] | Electric [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 22 | 28
WPL [Member] | Gas [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 126 | 123
WPL [Member] | Gas [Member] | Retail - residential [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 74 | 73
WPL [Member] | Gas [Member] | Retail - commercial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 44 | 42
WPL [Member] | Gas [Member] | Retail - industrial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 3 | 3
WPL [Member] | Gas [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 5 | 5
WPL [Member] | Other Utility [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 0 | 0
WPL [Member] | Other Utility [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | $ 0 | $ 0

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