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v3.23.3

Regulatory Matters (Tables) | 9 Months Ended
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Sep. 30, 2023
Regulatory Assets [Line Items] |
Regulatory Assets | Regulatory assets were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022
Tax-related | $919 |  | $929 |  | $825 |  | $848 |  | $94 |  | $81
Pension and OPEB costs | 371 |  | 392 |  | 187 |  | 197 |  | 184 |  | 195
Assets retired early | 282 |  | 70 |  | 267 |  | 53 |  | 15 |  | 17
Asset retirement obligations (AROs) | 199 |  | 151 |  | 155 |  | 110 |  | 44 |  | 41
Commodity cost recovery | 138 |  | 160 |  | 11 |  | 1 |  | 127 |  | 159
Derivatives | 72 |  | 84 |  | 27 |  | 48 |  | 45 |  | 36
IPL’s Duane Arnold Energy Center PPA amendment | 48 |  | 66 |  | 48 |  | 66 |  | — |  | —
WPL’s Western Wisconsin gas distribution expansion investments | 46 |  | 48 |  | — |  | — |  | 46 |  | 48
Other | 194 |  | 146 |  | 70 |  | 63 |  | 124 |  | 83
| $2,269 |  | $2,046 |  | $1,590 |  | $1,386 |  | $679 |  | $660
Regulatory Liabilities | Regulatory liabilities were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022
Tax-related | $569 |  | $579 |  | $301 |  | $303 |  | $268 |  | $276
Cost of removal obligations | 397 |  | 398 |  | 249 |  | 259 |  | 148 |  | 139
Derivatives | 91 |  | 210 |  | 52 |  | 115 |  | 39 |  | 95
Commodity cost recovery | 41 |  | 40 |  | 11 |  | 38 |  | 30 |  | 2
WPL’s West Riverside liquidated damages | 9 |  | 32 |  | — |  | — |  | 9 |  | 32
Electric transmission cost recovery | 6 |  | 20 |  | 6 |  | 10 |  | — |  | 10
Other | 74 |  | 45 |  | 36 |  | 29 |  | 38 |  | 16
| $1,187 |  | $1,324 |  | $655 |  | $754 |  | $532 |  | $570
IPL [Member] |
Regulatory Assets [Line Items] |
Regulatory Assets | Regulatory assets were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022
Tax-related | $919 |  | $929 |  | $825 |  | $848 |  | $94 |  | $81
Pension and OPEB costs | 371 |  | 392 |  | 187 |  | 197 |  | 184 |  | 195
Assets retired early | 282 |  | 70 |  | 267 |  | 53 |  | 15 |  | 17
Asset retirement obligations (AROs) | 199 |  | 151 |  | 155 |  | 110 |  | 44 |  | 41
Commodity cost recovery | 138 |  | 160 |  | 11 |  | 1 |  | 127 |  | 159
Derivatives | 72 |  | 84 |  | 27 |  | 48 |  | 45 |  | 36
IPL’s Duane Arnold Energy Center PPA amendment | 48 |  | 66 |  | 48 |  | 66 |  | — |  | —
WPL’s Western Wisconsin gas distribution expansion investments | 46 |  | 48 |  | — |  | — |  | 46 |  | 48
Other | 194 |  | 146 |  | 70 |  | 63 |  | 124 |  | 83
| $2,269 |  | $2,046 |  | $1,590 |  | $1,386 |  | $679 |  | $660
Regulatory Liabilities | Regulatory liabilities were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022
Tax-related | $569 |  | $579 |  | $301 |  | $303 |  | $268 |  | $276
Cost of removal obligations | 397 |  | 398 |  | 249 |  | 259 |  | 148 |  | 139
Derivatives | 91 |  | 210 |  | 52 |  | 115 |  | 39 |  | 95
Commodity cost recovery | 41 |  | 40 |  | 11 |  | 38 |  | 30 |  | 2
WPL’s West Riverside liquidated damages | 9 |  | 32 |  | — |  | — |  | 9 |  | 32
Electric transmission cost recovery | 6 |  | 20 |  | 6 |  | 10 |  | — |  | 10
Other | 74 |  | 45 |  | 36 |  | 29 |  | 38 |  | 16
| $1,187 |  | $1,324 |  | $655 |  | $754 |  | $532 |  | $570
WPL [Member] |
Regulatory Assets [Line Items] |
Regulatory Assets | Regulatory assets were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022
Tax-related | $919 |  | $929 |  | $825 |  | $848 |  | $94 |  | $81
Pension and OPEB costs | 371 |  | 392 |  | 187 |  | 197 |  | 184 |  | 195
Assets retired early | 282 |  | 70 |  | 267 |  | 53 |  | 15 |  | 17
Asset retirement obligations (AROs) | 199 |  | 151 |  | 155 |  | 110 |  | 44 |  | 41
Commodity cost recovery | 138 |  | 160 |  | 11 |  | 1 |  | 127 |  | 159
Derivatives | 72 |  | 84 |  | 27 |  | 48 |  | 45 |  | 36
IPL’s Duane Arnold Energy Center PPA amendment | 48 |  | 66 |  | 48 |  | 66 |  | — |  | —
WPL’s Western Wisconsin gas distribution expansion investments | 46 |  | 48 |  | — |  | — |  | 46 |  | 48
Other | 194 |  | 146 |  | 70 |  | 63 |  | 124 |  | 83
| $2,269 |  | $2,046 |  | $1,590 |  | $1,386 |  | $679 |  | $660
Regulatory Liabilities | Regulatory liabilities were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022 |  | September 30, 2023 |  | December 31, 2022
Tax-related | $569 |  | $579 |  | $301 |  | $303 |  | $268 |  | $276
Cost of removal obligations | 397 |  | 398 |  | 249 |  | 259 |  | 148 |  | 139
Derivatives | 91 |  | 210 |  | 52 |  | 115 |  | 39 |  | 95
Commodity cost recovery | 41 |  | 40 |  | 11 |  | 38 |  | 30 |  | 2
WPL’s West Riverside liquidated damages | 9 |  | 32 |  | — |  | — |  | 9 |  | 32
Electric transmission cost recovery | 6 |  | 20 |  | 6 |  | 10 |  | — |  | 10
Other | 74 |  | 45 |  | 36 |  | 29 |  | 38 |  | 16
| $1,187 |  | $1,324 |  | $655 |  | $754 |  | $532 |  | $570

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