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Revenues (Tables) | 6 Months Ended
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Jun. 30, 2021
Disaggregation of Revenue [Line Items] |
Disaggregation of Revenue | Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Three Months Ended June 30 | 2021 |  | 2020 |  | 2021 |  | 2020 |  | 2021 |  | 2020
Electric Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | $258 |  | $251 |  | $142 |  | $136 |  | $116 |  | $115
Retail - commercial | 175 |  | 163 |  | 115 |  | 109 |  | 60 |  | 54
Retail - industrial | 210 |  | 197 |  | 116 |  | 114 |  | 94 |  | 83
Wholesale | 47 |  | 40 |  | 15 |  | 13 |  | 32 |  | 27
Bulk power and other | 27 |  | 24 |  | 14 |  | 16 |  | 13 |  | 8
Total Electric Utility | 717 |  | 675 |  | 402 |  | 388 |  | 315 |  | 287
Gas Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | 39 |  | 33 |  | 24 |  | 18 |  | 15 |  | 15
Retail - commercial | 19 |  | 15 |  | 12 |  | 8 |  | 7 |  | 7
Retail - industrial | 3 |  | 2 |  | 2 |  | 2 |  | 1 |  | —
Transportation/other | 8 |  | 9 |  | 5 |  | 6 |  | 3 |  | 3
Total Gas Utility | 69 |  | 59 |  | 43 |  | 34 |  | 26 |  | 25
Other Utility: |  |  |  |  |  |  |  |  |  |  |
Steam | 9 |  | 9 |  | 9 |  | 9 |  | — |  | —
Other utility | 1 |  | 1 |  | 1 |  | 1 |  | — |  | —
Total Other Utility | 10 |  | 10 |  | 10 |  | 10 |  | — |  | —
Non-Utility and Other: |  |  |  |  |  |  |  |  |  |  |
Transportation and other | 21 |  | 19 |  | — |  | — |  | — |  | —
Total Non-Utility and Other | 21 |  | 19 |  | — |  | — |  | — |  | —
Total revenues | $817 |  | $763 |  | $455 |  | $432 |  | $341 |  | $312
| Alliant Energy |  | IPL |  | WPL
Six Months Ended June 30 | 2021 |  | 2020 |  | 2021 |  | 2020 |  | 2021 |  | 2020
Electric Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | $520 |  | $517 |  | $281 |  | $283 |  | $239 |  | $234
Retail - commercial | 347 |  | 346 |  | 225 |  | 229 |  | 122 |  | 117
Retail - industrial | 412 |  | 407 |  | 228 |  | 235 |  | 184 |  | 172
Wholesale | 87 |  | 80 |  | 26 |  | 27 |  | 61 |  | 53
Bulk power and other | 52 |  | 55 |  | 28 |  | 39 |  | 24 |  | 16
Total Electric Utility | 1,418 |  | 1,405 |  | 788 |  | 813 |  | 630 |  | 592
Gas Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | 138 |  | 124 |  | 76 |  | 67 |  | 62 |  | 57
Retail - commercial | 72 |  | 60 |  | 39 |  | 32 |  | 33 |  | 28
Retail - industrial | 8 |  | 6 |  | 5 |  | 4 |  | 3 |  | 2
Transportation/other | 21 |  | 21 |  | 14 |  | 14 |  | 7 |  | 7
Total Gas Utility | 239 |  | 211 |  | 134 |  | 117 |  | 105 |  | 94
Other Utility: |  |  |  |  |  |  |  |  |  |  |
Steam | 18 |  | 19 |  | 18 |  | 19 |  | — |  | —
Other utility | 5 |  | 3 |  | 4 |  | 2 |  | 1 |  | 1
Total Other Utility | 23 |  | 22 |  | 22 |  | 21 |  | 1 |  | 1
Non-Utility and Other: |  |  |  |  |  |  |  |  |  |  |
Transportation and other | 38 |  | 41 |  | — |  | — |  | — |  | —
Total Non-Utility and Other | 38 |  | 41 |  | — |  | — |  | — |  | —
Total revenues | $1,718 |  | $1,679 |  | $944 |  | $951 |  | $736 |  | $687
IPL [Member] |
Disaggregation of Revenue [Line Items] |
Disaggregation of Revenue | Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Three Months Ended June 30 | 2021 |  | 2020 |  | 2021 |  | 2020 |  | 2021 |  | 2020
Electric Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | $258 |  | $251 |  | $142 |  | $136 |  | $116 |  | $115
Retail - commercial | 175 |  | 163 |  | 115 |  | 109 |  | 60 |  | 54
Retail - industrial | 210 |  | 197 |  | 116 |  | 114 |  | 94 |  | 83
Wholesale | 47 |  | 40 |  | 15 |  | 13 |  | 32 |  | 27
Bulk power and other | 27 |  | 24 |  | 14 |  | 16 |  | 13 |  | 8
Total Electric Utility | 717 |  | 675 |  | 402 |  | 388 |  | 315 |  | 287
Gas Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | 39 |  | 33 |  | 24 |  | 18 |  | 15 |  | 15
Retail - commercial | 19 |  | 15 |  | 12 |  | 8 |  | 7 |  | 7
Retail - industrial | 3 |  | 2 |  | 2 |  | 2 |  | 1 |  | —
Transportation/other | 8 |  | 9 |  | 5 |  | 6 |  | 3 |  | 3
Total Gas Utility | 69 |  | 59 |  | 43 |  | 34 |  | 26 |  | 25
Other Utility: |  |  |  |  |  |  |  |  |  |  |
Steam | 9 |  | 9 |  | 9 |  | 9 |  | — |  | —
Other utility | 1 |  | 1 |  | 1 |  | 1 |  | — |  | —
Total Other Utility | 10 |  | 10 |  | 10 |  | 10 |  | — |  | —
Non-Utility and Other: |  |  |  |  |  |  |  |  |  |  |
Transportation and other | 21 |  | 19 |  | — |  | — |  | — |  | —
Total Non-Utility and Other | 21 |  | 19 |  | — |  | — |  | — |  | —
Total revenues | $817 |  | $763 |  | $455 |  | $432 |  | $341 |  | $312
| Alliant Energy |  | IPL |  | WPL
Six Months Ended June 30 | 2021 |  | 2020 |  | 2021 |  | 2020 |  | 2021 |  | 2020
Electric Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | $520 |  | $517 |  | $281 |  | $283 |  | $239 |  | $234
Retail - commercial | 347 |  | 346 |  | 225 |  | 229 |  | 122 |  | 117
Retail - industrial | 412 |  | 407 |  | 228 |  | 235 |  | 184 |  | 172
Wholesale | 87 |  | 80 |  | 26 |  | 27 |  | 61 |  | 53
Bulk power and other | 52 |  | 55 |  | 28 |  | 39 |  | 24 |  | 16
Total Electric Utility | 1,418 |  | 1,405 |  | 788 |  | 813 |  | 630 |  | 592
Gas Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | 138 |  | 124 |  | 76 |  | 67 |  | 62 |  | 57
Retail - commercial | 72 |  | 60 |  | 39 |  | 32 |  | 33 |  | 28
Retail - industrial | 8 |  | 6 |  | 5 |  | 4 |  | 3 |  | 2
Transportation/other | 21 |  | 21 |  | 14 |  | 14 |  | 7 |  | 7
Total Gas Utility | 239 |  | 211 |  | 134 |  | 117 |  | 105 |  | 94
Other Utility: |  |  |  |  |  |  |  |  |  |  |
Steam | 18 |  | 19 |  | 18 |  | 19 |  | — |  | —
Other utility | 5 |  | 3 |  | 4 |  | 2 |  | 1 |  | 1
Total Other Utility | 23 |  | 22 |  | 22 |  | 21 |  | 1 |  | 1
Non-Utility and Other: |  |  |  |  |  |  |  |  |  |  |
Transportation and other | 38 |  | 41 |  | — |  | — |  | — |  | —
Total Non-Utility and Other | 38 |  | 41 |  | — |  | — |  | — |  | —
Total revenues | $1,718 |  | $1,679 |  | $944 |  | $951 |  | $736 |  | $687
WPL [Member] |
Disaggregation of Revenue [Line Items] |
Disaggregation of Revenue | Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Three Months Ended June 30 | 2021 |  | 2020 |  | 2021 |  | 2020 |  | 2021 |  | 2020
Electric Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | $258 |  | $251 |  | $142 |  | $136 |  | $116 |  | $115
Retail - commercial | 175 |  | 163 |  | 115 |  | 109 |  | 60 |  | 54
Retail - industrial | 210 |  | 197 |  | 116 |  | 114 |  | 94 |  | 83
Wholesale | 47 |  | 40 |  | 15 |  | 13 |  | 32 |  | 27
Bulk power and other | 27 |  | 24 |  | 14 |  | 16 |  | 13 |  | 8
Total Electric Utility | 717 |  | 675 |  | 402 |  | 388 |  | 315 |  | 287
Gas Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | 39 |  | 33 |  | 24 |  | 18 |  | 15 |  | 15
Retail - commercial | 19 |  | 15 |  | 12 |  | 8 |  | 7 |  | 7
Retail - industrial | 3 |  | 2 |  | 2 |  | 2 |  | 1 |  | —
Transportation/other | 8 |  | 9 |  | 5 |  | 6 |  | 3 |  | 3
Total Gas Utility | 69 |  | 59 |  | 43 |  | 34 |  | 26 |  | 25
Other Utility: |  |  |  |  |  |  |  |  |  |  |
Steam | 9 |  | 9 |  | 9 |  | 9 |  | — |  | —
Other utility | 1 |  | 1 |  | 1 |  | 1 |  | — |  | —
Total Other Utility | 10 |  | 10 |  | 10 |  | 10 |  | — |  | —
Non-Utility and Other: |  |  |  |  |  |  |  |  |  |  |
Transportation and other | 21 |  | 19 |  | — |  | — |  | — |  | —
Total Non-Utility and Other | 21 |  | 19 |  | — |  | — |  | — |  | —
Total revenues | $817 |  | $763 |  | $455 |  | $432 |  | $341 |  | $312
| Alliant Energy |  | IPL |  | WPL
Six Months Ended June 30 | 2021 |  | 2020 |  | 2021 |  | 2020 |  | 2021 |  | 2020
Electric Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | $520 |  | $517 |  | $281 |  | $283 |  | $239 |  | $234
Retail - commercial | 347 |  | 346 |  | 225 |  | 229 |  | 122 |  | 117
Retail - industrial | 412 |  | 407 |  | 228 |  | 235 |  | 184 |  | 172
Wholesale | 87 |  | 80 |  | 26 |  | 27 |  | 61 |  | 53
Bulk power and other | 52 |  | 55 |  | 28 |  | 39 |  | 24 |  | 16
Total Electric Utility | 1,418 |  | 1,405 |  | 788 |  | 813 |  | 630 |  | 592
Gas Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | 138 |  | 124 |  | 76 |  | 67 |  | 62 |  | 57
Retail - commercial | 72 |  | 60 |  | 39 |  | 32 |  | 33 |  | 28
Retail - industrial | 8 |  | 6 |  | 5 |  | 4 |  | 3 |  | 2
Transportation/other | 21 |  | 21 |  | 14 |  | 14 |  | 7 |  | 7
Total Gas Utility | 239 |  | 211 |  | 134 |  | 117 |  | 105 |  | 94
Other Utility: |  |  |  |  |  |  |  |  |  |  |
Steam | 18 |  | 19 |  | 18 |  | 19 |  | — |  | —
Other utility | 5 |  | 3 |  | 4 |  | 2 |  | 1 |  | 1
Total Other Utility | 23 |  | 22 |  | 22 |  | 21 |  | 1 |  | 1
Non-Utility and Other: |  |  |  |  |  |  |  |  |  |  |
Transportation and other | 38 |  | 41 |  | — |  | — |  | — |  | —
Total Non-Utility and Other | 38 |  | 41 |  | — |  | — |  | — |  | —
Total revenues | $1,718 |  | $1,679 |  | $944 |  | $951 |  | $736 |  | $687

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