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Regulatory Matters | 3 Months Ended
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Mar. 31, 2023
Public Utilities, General Disclosures [Line Items] |
Regulatory Matters | REGULATORY MATTERS Regulatory Assets and Regulatory Liabilities - Regulatory assets were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| March 31, 2023 |  | December 31, 2022 |  | March 31, 2023 |  | December 31, 2022 |  | March 31, 2023 |  | December 31, 2022
Tax-related | $942 |  | $929 |  | $857 |  | $848 |  | $85 |  | $81
Pension and OPEB costs | 385 |  | 392 |  | 193 |  | 197 |  | 192 |  | 195
Asset retirement obligations | 156 |  | 151 |  | 115 |  | 110 |  | 41 |  | 41
Commodity cost recovery | 152 |  | 160 |  | 4 |  | 1 |  | 148 |  | 159
Derivatives | 101 |  | 84 |  | 37 |  | 48 |  | 64 |  | 36
Assets retired early | 67 |  | 70 |  | 51 |  | 53 |  | 16 |  | 17
IPL’s Duane Arnold Energy Center PPA amendment | 60 |  | 66 |  | 60 |  | 66 |  | — |  | —
WPL’s Western Wisconsin gas distribution expansion investments | 48 |  | 48 |  | — |  | — |  | 48 |  | 48
Other | 169 |  | 146 |  | 66 |  | 63 |  | 103 |  | 83
| $2,080 |  | $2,046 |  | $1,383 |  | $1,386 |  | $697 |  | $660
Derivatives - Refer to Note 11 for discussion of changes in Alliant Energy’s, IPL’s and WPL’s derivative liabilities/assets during the three months ended March 31, 2023, which result in comparable changes to regulatory assets/liabilities on the balance sheets. Regulatory liabilities were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| March 31, 2023 |  | December 31, 2022 |  | March 31, 2023 |  | December 31, 2022 |  | March 31, 2023 |  | December 31, 2022
Tax-related | $575 |  | $579 |  | $302 |  | $303 |  | $273 |  | $276
Cost of removal obligations | 403 |  | 398 |  | 261 |  | 259 |  | 142 |  | 139
Derivatives | 117 |  | 210 |  | 64 |  | 115 |  | 53 |  | 95
Electric transmission cost recovery | 26 |  | 20 |  | 19 |  | 10 |  | 7 |  | 10
WPL’s West Riverside liquidated damages | 24 |  | 32 |  | — |  | — |  | 24 |  | 32
Commodity cost recovery | 22 |  | 40 |  | 8 |  | 38 |  | 14 |  | 2
Other | 64 |  | 45 |  | 43 |  | 29 |  | 21 |  | 16
| $1,231 |  | $1,324 |  | $697 |  | $754 |  | $534 |  | $570
IPL [Member] |
Public Utilities, General Disclosures [Line Items] |
Regulatory Matters | REGULATORY MATTERS Regulatory Assets and Regulatory Liabilities - Regulatory assets were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| March 31, 2023 |  | December 31, 2022 |  | March 31, 2023 |  | December 31, 2022 |  | March 31, 2023 |  | December 31, 2022
Tax-related | $942 |  | $929 |  | $857 |  | $848 |  | $85 |  | $81
Pension and OPEB costs | 385 |  | 392 |  | 193 |  | 197 |  | 192 |  | 195
Asset retirement obligations | 156 |  | 151 |  | 115 |  | 110 |  | 41 |  | 41
Commodity cost recovery | 152 |  | 160 |  | 4 |  | 1 |  | 148 |  | 159
Derivatives | 101 |  | 84 |  | 37 |  | 48 |  | 64 |  | 36
Assets retired early | 67 |  | 70 |  | 51 |  | 53 |  | 16 |  | 17
IPL’s Duane Arnold Energy Center PPA amendment | 60 |  | 66 |  | 60 |  | 66 |  | — |  | —
WPL’s Western Wisconsin gas distribution expansion investments | 48 |  | 48 |  | — |  | — |  | 48 |  | 48
Other | 169 |  | 146 |  | 66 |  | 63 |  | 103 |  | 83
| $2,080 |  | $2,046 |  | $1,383 |  | $1,386 |  | $697 |  | $660
Derivatives - Refer to Note 11 for discussion of changes in Alliant Energy’s, IPL’s and WPL’s derivative liabilities/assets during the three months ended March 31, 2023, which result in comparable changes to regulatory assets/liabilities on the balance sheets. Regulatory liabilities were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| March 31, 2023 |  | December 31, 2022 |  | March 31, 2023 |  | December 31, 2022 |  | March 31, 2023 |  | December 31, 2022
Tax-related | $575 |  | $579 |  | $302 |  | $303 |  | $273 |  | $276
Cost of removal obligations | 403 |  | 398 |  | 261 |  | 259 |  | 142 |  | 139
Derivatives | 117 |  | 210 |  | 64 |  | 115 |  | 53 |  | 95
Electric transmission cost recovery | 26 |  | 20 |  | 19 |  | 10 |  | 7 |  | 10
WPL’s West Riverside liquidated damages | 24 |  | 32 |  | — |  | — |  | 24 |  | 32
Commodity cost recovery | 22 |  | 40 |  | 8 |  | 38 |  | 14 |  | 2
Other | 64 |  | 45 |  | 43 |  | 29 |  | 21 |  | 16
| $1,231 |  | $1,324 |  | $697 |  | $754 |  | $534 |  | $570
WPL [Member] |
Public Utilities, General Disclosures [Line Items] |
Regulatory Matters | REGULATORY MATTERS Regulatory Assets and Regulatory Liabilities - Regulatory assets were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| March 31, 2023 |  | December 31, 2022 |  | March 31, 2023 |  | December 31, 2022 |  | March 31, 2023 |  | December 31, 2022
Tax-related | $942 |  | $929 |  | $857 |  | $848 |  | $85 |  | $81
Pension and OPEB costs | 385 |  | 392 |  | 193 |  | 197 |  | 192 |  | 195
Asset retirement obligations | 156 |  | 151 |  | 115 |  | 110 |  | 41 |  | 41
Commodity cost recovery | 152 |  | 160 |  | 4 |  | 1 |  | 148 |  | 159
Derivatives | 101 |  | 84 |  | 37 |  | 48 |  | 64 |  | 36
Assets retired early | 67 |  | 70 |  | 51 |  | 53 |  | 16 |  | 17
IPL’s Duane Arnold Energy Center PPA amendment | 60 |  | 66 |  | 60 |  | 66 |  | — |  | —
WPL’s Western Wisconsin gas distribution expansion investments | 48 |  | 48 |  | — |  | — |  | 48 |  | 48
Other | 169 |  | 146 |  | 66 |  | 63 |  | 103 |  | 83
| $2,080 |  | $2,046 |  | $1,383 |  | $1,386 |  | $697 |  | $660
Derivatives - Refer to Note 11 for discussion of changes in Alliant Energy’s, IPL’s and WPL’s derivative liabilities/assets during the three months ended March 31, 2023, which result in comparable changes to regulatory assets/liabilities on the balance sheets. Regulatory liabilities were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| March 31, 2023 |  | December 31, 2022 |  | March 31, 2023 |  | December 31, 2022 |  | March 31, 2023 |  | December 31, 2022
Tax-related | $575 |  | $579 |  | $302 |  | $303 |  | $273 |  | $276
Cost of removal obligations | 403 |  | 398 |  | 261 |  | 259 |  | 142 |  | 139
Derivatives | 117 |  | 210 |  | 64 |  | 115 |  | 53 |  | 95
Electric transmission cost recovery | 26 |  | 20 |  | 19 |  | 10 |  | 7 |  | 10
WPL’s West Riverside liquidated damages | 24 |  | 32 |  | — |  | — |  | 24 |  | 32
Commodity cost recovery | 22 |  | 40 |  | 8 |  | 38 |  | 14 |  | 2
Other | 64 |  | 45 |  | 43 |  | 29 |  | 21 |  | 16
| $1,231 |  | $1,324 |  | $697 |  | $754 |  | $534 |  | $570

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