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Revenues (Tables) | 3 Months Ended
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Mar. 31, 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 March 31 | 2021 |  | 2020 |  | 2021 |  | 2020 |  | 2021 |  | 2020
Electric Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | $262 |  | $266 |  | $139 |  | $147 |  | $123 |  | $119
Retail - commercial | 172 |  | 183 |  | 110 |  | 120 |  | 62 |  | 63
Retail - industrial | 202 |  | 210 |  | 112 |  | 121 |  | 90 |  | 89
Wholesale | 40 |  | 40 |  | 11 |  | 14 |  | 29 |  | 26
Bulk power and other | 25 |  | 31 |  | 14 |  | 23 |  | 11 |  | 8
Total Electric Utility | 701 |  | 730 |  | 386 |  | 425 |  | 315 |  | 305
Gas Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | 99 |  | 91 |  | 52 |  | 49 |  | 47 |  | 42
Retail - commercial | 53 |  | 45 |  | 27 |  | 24 |  | 26 |  | 21
Retail - industrial | 5 |  | 4 |  | 3 |  | 2 |  | 2 |  | 2
Transportation/other | 13 |  | 12 |  | 9 |  | 8 |  | 4 |  | 4
Total Gas Utility | 170 |  | 152 |  | 91 |  | 83 |  | 79 |  | 69
Other Utility: |  |  |  |  |  |  |  |  |  |  |
Steam | 9 |  | 10 |  | 9 |  | 10 |  | — |  | —
Other utility | 4 |  | 2 |  | 3 |  | 1 |  | 1 |  | 1
Total Other Utility | 13 |  | 12 |  | 12 |  | 11 |  | 1 |  | 1
Non-Utility and Other: |  |  |  |  |  |  |  |  |  |  |
Transportation and other | 17 |  | 22 |  | — |  | — |  | — |  | —
Total Non-Utility and Other | 17 |  | 22 |  | — |  | — |  | — |  | —
Total revenues | $901 |  | $916 |  | $489 |  | $519 |  | $395 |  | $375
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 March 31 | 2021 |  | 2020 |  | 2021 |  | 2020 |  | 2021 |  | 2020
Electric Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | $262 |  | $266 |  | $139 |  | $147 |  | $123 |  | $119
Retail - commercial | 172 |  | 183 |  | 110 |  | 120 |  | 62 |  | 63
Retail - industrial | 202 |  | 210 |  | 112 |  | 121 |  | 90 |  | 89
Wholesale | 40 |  | 40 |  | 11 |  | 14 |  | 29 |  | 26
Bulk power and other | 25 |  | 31 |  | 14 |  | 23 |  | 11 |  | 8
Total Electric Utility | 701 |  | 730 |  | 386 |  | 425 |  | 315 |  | 305
Gas Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | 99 |  | 91 |  | 52 |  | 49 |  | 47 |  | 42
Retail - commercial | 53 |  | 45 |  | 27 |  | 24 |  | 26 |  | 21
Retail - industrial | 5 |  | 4 |  | 3 |  | 2 |  | 2 |  | 2
Transportation/other | 13 |  | 12 |  | 9 |  | 8 |  | 4 |  | 4
Total Gas Utility | 170 |  | 152 |  | 91 |  | 83 |  | 79 |  | 69
Other Utility: |  |  |  |  |  |  |  |  |  |  |
Steam | 9 |  | 10 |  | 9 |  | 10 |  | — |  | —
Other utility | 4 |  | 2 |  | 3 |  | 1 |  | 1 |  | 1
Total Other Utility | 13 |  | 12 |  | 12 |  | 11 |  | 1 |  | 1
Non-Utility and Other: |  |  |  |  |  |  |  |  |  |  |
Transportation and other | 17 |  | 22 |  | — |  | — |  | — |  | —
Total Non-Utility and Other | 17 |  | 22 |  | — |  | — |  | — |  | —
Total revenues | $901 |  | $916 |  | $489 |  | $519 |  | $395 |  | $375
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 March 31 | 2021 |  | 2020 |  | 2021 |  | 2020 |  | 2021 |  | 2020
Electric Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | $262 |  | $266 |  | $139 |  | $147 |  | $123 |  | $119
Retail - commercial | 172 |  | 183 |  | 110 |  | 120 |  | 62 |  | 63
Retail - industrial | 202 |  | 210 |  | 112 |  | 121 |  | 90 |  | 89
Wholesale | 40 |  | 40 |  | 11 |  | 14 |  | 29 |  | 26
Bulk power and other | 25 |  | 31 |  | 14 |  | 23 |  | 11 |  | 8
Total Electric Utility | 701 |  | 730 |  | 386 |  | 425 |  | 315 |  | 305
Gas Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | 99 |  | 91 |  | 52 |  | 49 |  | 47 |  | 42
Retail - commercial | 53 |  | 45 |  | 27 |  | 24 |  | 26 |  | 21
Retail - industrial | 5 |  | 4 |  | 3 |  | 2 |  | 2 |  | 2
Transportation/other | 13 |  | 12 |  | 9 |  | 8 |  | 4 |  | 4
Total Gas Utility | 170 |  | 152 |  | 91 |  | 83 |  | 79 |  | 69
Other Utility: |  |  |  |  |  |  |  |  |  |  |
Steam | 9 |  | 10 |  | 9 |  | 10 |  | — |  | —
Other utility | 4 |  | 2 |  | 3 |  | 1 |  | 1 |  | 1
Total Other Utility | 13 |  | 12 |  | 12 |  | 11 |  | 1 |  | 1
Non-Utility and Other: |  |  |  |  |  |  |  |  |  |  |
Transportation and other | 17 |  | 22 |  | — |  | — |  | — |  | —
Total Non-Utility and Other | 17 |  | 22 |  | — |  | — |  | — |  | —
Total revenues | $901 |  | $916 |  | $489 |  | $519 |  | $395 |  | $375

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