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Revenue (Disaggregation of Revenues) (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2022 | Mar. 31, 2021
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | $ 1,068 | $ 901
Electric [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 773 | 701
Electric [Member] | Retail - residential [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 293 | 262
Electric [Member] | Retail - commercial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 188 | 172
Electric [Member] | Retail - industrial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 211 | 202
Electric [Member] | Wholesale [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 47 | 40
Electric [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 34 | 25
Gas [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 262 | 170
Gas [Member] | Retail - residential [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 158 | 99
Gas [Member] | Retail - commercial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 82 | 53
Gas [Member] | Retail - industrial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 8 | 5
Gas [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 14 | 13
Other Utility [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 11 | 13
Other Utility [Member] | Steam [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 9 | 9
Other Utility [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 2 | 4
Non-utility and Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 22 | 17
Non-utility and Other [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 22 | 17
IPL [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 550 | 489
IPL [Member] | Electric [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 400 | 386
IPL [Member] | Electric [Member] | Retail - residential [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 150 | 139
IPL [Member] | Electric [Member] | Retail - commercial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 118 | 110
IPL [Member] | Electric [Member] | Retail - industrial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 111 | 112
IPL [Member] | Electric [Member] | Wholesale [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 15 | 11
IPL [Member] | Electric [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 6 | 14
IPL [Member] | Gas [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 139 | 91
IPL [Member] | Gas [Member] | Retail - residential [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 85 | 52
IPL [Member] | Gas [Member] | Retail - commercial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 40 | 27
IPL [Member] | Gas [Member] | Retail - industrial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 5 | 3
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 | 12
IPL [Member] | Other Utility [Member] | Steam [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 9 | 9
IPL [Member] | Other Utility [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 2 | 3
WPL [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 496 | 395
WPL [Member] | Electric [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 373 | 315
WPL [Member] | Electric [Member] | Retail - residential [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 143 | 123
WPL [Member] | Electric [Member] | Retail - commercial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 70 | 62
WPL [Member] | Electric [Member] | Retail - industrial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 100 | 90
WPL [Member] | Electric [Member] | Wholesale [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 32 | 29
WPL [Member] | Electric [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 28 | 11
WPL [Member] | Gas [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 123 | 79
WPL [Member] | Gas [Member] | Retail - residential [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 73 | 47
WPL [Member] | Gas [Member] | Retail - commercial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 42 | 26
WPL [Member] | Gas [Member] | Retail - industrial [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 3 | 2
WPL [Member] | Gas [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 5 | 4
WPL [Member] | Other Utility [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | 0 | 1
WPL [Member] | Other Utility [Member] | Other [Member] |  |
Disaggregation of Revenue [Line Items] |  |
Revenue from contracts with customers | $ 0 | $ 1

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