v3.25.2
Revenue (Disaggregation of Revenues) (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers $ 961 $ 894 $ 2,088 $ 1,925
Electric [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 851 789 1,703 1,580
Electric [Member] | Retail - residential [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 295 291 618 588
Electric [Member] | Retail - commercial [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 211 191 425 377
Electric [Member] | Retail - industrial [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 240 237 475 460
Electric [Member] | Wholesale [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 49 43 97 89
Electric [Member] | Other [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 56 27 88 66
Gas [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 76 69 316 273
Gas [Member] | Retail - residential [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 41 38 188 165
Gas [Member] | Retail - commercial [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 20 19 94 80
Gas [Member] | Retail - industrial [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 3 2 8 6
Gas [Member] | Other [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 12 10 26 22
Other Utility [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 11 10 25 24
Other Utility [Member] | Steam [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 9 9 19 20
Other Utility [Member] | Other [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 2 1 6 4
Non-Utility and Other [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 23 26 44 48
Non-Utility and Other [Member] | Other [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 23 26 44 48
IPL [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 469 453 1,030 966
IPL [Member] | Electric [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 418 404 848 795
IPL [Member] | Electric [Member] | Retail - residential [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 142 151 297 301
IPL [Member] | Electric [Member] | Retail - commercial [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 135 118 271 232
IPL [Member] | Electric [Member] | Retail - industrial [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 118 118 236 229
IPL [Member] | Electric [Member] | Wholesale [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 14 13 28 26
IPL [Member] | Electric [Member] | Other [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 9 4 16 7
IPL [Member] | Gas [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 40 40 158 148
IPL [Member] | Gas [Member] | Retail - residential [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 21 22 95 90
IPL [Member] | Gas [Member] | Retail - commercial [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 10 11 43 41
IPL [Member] | Gas [Member] | Retail - industrial [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 2 1 4 4
IPL [Member] | Gas [Member] | Other [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 7 6 16 13
IPL [Member] | Other Utility [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 11 9 24 23
IPL [Member] | Other Utility [Member] | Steam [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 9 9 19 20
IPL [Member] | Other Utility [Member] | Other [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 2 0 5 3
WPL [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 469 415 1,014 911
WPL [Member] | Electric [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 433 385 855 785
WPL [Member] | Electric [Member] | Retail - residential [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 153 140 321 287
WPL [Member] | Electric [Member] | Retail - commercial [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 76 73 154 145
WPL [Member] | Electric [Member] | Retail - industrial [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 122 119 239 231
WPL [Member] | Electric [Member] | Wholesale [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 35 30 69 63
WPL [Member] | Electric [Member] | Other [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 47 23 72 59
WPL [Member] | Gas [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 36 29 158 125
WPL [Member] | Gas [Member] | Retail - residential [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 20 16 93 75
WPL [Member] | Gas [Member] | Retail - commercial [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 10 8 51 39
WPL [Member] | Gas [Member] | Retail - industrial [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 1 1 4 2
WPL [Member] | Gas [Member] | Other [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 5 4 10 9
WPL [Member] | Other Utility [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers 0 1 1 1
WPL [Member] | Other Utility [Member] | Other [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from contracts with customers $ 0 $ 1 $ 1 $ 1