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v3.20.2

Regulatory Matters (Tables) | 9 Months Ended
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Sep. 30, 2020
Regulatory Assets [Line Items] |
Regulatory Assets | Regulatory assets were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019
Tax-related |  | $877 |  |  |  | $818 |  |  |  | $829 |  |  |  | $777 |  |  |  | $48 |  |  |  | $41 |
Pension and OPEB costs | 492 |  |  | 524 |  |  | 247 |  |  | 263 |  |  | 245 |  |  | 261 |
Assets retired early | 118 |  |  | 134 |  |  | 79 |  |  | 88 |  |  | 39 |  |  | 46 |
Asset retirement obligations | 115 |  |  | 112 |  |  | 79 |  |  | 76 |  |  | 36 |  |  | 36 |
IPL’s DAEC PPA amendment | 110 |  |  | 108 |  |  | 110 |  |  | 108 |  |  | — |  |  | — |
Derivatives | 20 |  |  | 39 |  |  | 8 |  |  | 18 |  |  | 12 |  |  | 21 |
Emission allowances | 19 |  |  | 21 |  |  | 19 |  |  | 21 |  |  | — |  |  | — |
Other | 85 |  |  | 89 |  |  | 47 |  |  | 49 |  |  | 38 |  |  | 40 |
|  | $1,836 |  |  |  | $1,845 |  |  |  | $1,418 |  |  |  | $1,400 |  |  |  | $418 |  |  |  | $445 |
Regulatory Liabilities | Regulatory liabilities were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019
Tax-related |  | $746 |  |  |  | $836 |  |  |  | $334 |  |  |  | $351 |  |  |  | $412 |  |  |  | $485 |
Cost of removal obligations | 371 |  |  | 388 |  |  | 241 |  |  | 257 |  |  | 130 |  |  | 131 |
Electric transmission cost recovery | 62 |  |  | 88 |  |  | 30 |  |  | 51 |  |  | 32 |  |  | 37 |
Derivatives | 40 |  |  | 20 |  |  | 27 |  |  | 17 |  |  | 13 |  |  | 3 |
WPL’s West Riverside liquidated damages | 36 |  |  | — |  |  | — |  |  | — |  |  | 36 |  |  | — |
Commodity cost recovery | 22 |  |  | 24 |  |  | 19 |  |  | 9 |  |  | 3 |  |  | 15 |
WPL’s earnings sharing mechanism | 22 |  |  | 22 |  |  | — |  |  | — |  |  | 22 |  |  | 22 |
Other | 52 |  |  | 46 |  |  | 40 |  |  | 30 |  |  | 12 |  |  | 16 |
|  | $1,351 |  |  |  | $1,424 |  |  |  | $691 |  |  |  | $715 |  |  |  | $660 |  |  |  | $709 |
IPL [Member] |
Regulatory Assets [Line Items] |
Regulatory Assets | Regulatory assets were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019
Tax-related |  | $877 |  |  |  | $818 |  |  |  | $829 |  |  |  | $777 |  |  |  | $48 |  |  |  | $41 |
Pension and OPEB costs | 492 |  |  | 524 |  |  | 247 |  |  | 263 |  |  | 245 |  |  | 261 |
Assets retired early | 118 |  |  | 134 |  |  | 79 |  |  | 88 |  |  | 39 |  |  | 46 |
Asset retirement obligations | 115 |  |  | 112 |  |  | 79 |  |  | 76 |  |  | 36 |  |  | 36 |
IPL’s DAEC PPA amendment | 110 |  |  | 108 |  |  | 110 |  |  | 108 |  |  | — |  |  | — |
Derivatives | 20 |  |  | 39 |  |  | 8 |  |  | 18 |  |  | 12 |  |  | 21 |
Emission allowances | 19 |  |  | 21 |  |  | 19 |  |  | 21 |  |  | — |  |  | — |
Other | 85 |  |  | 89 |  |  | 47 |  |  | 49 |  |  | 38 |  |  | 40 |
|  | $1,836 |  |  |  | $1,845 |  |  |  | $1,418 |  |  |  | $1,400 |  |  |  | $418 |  |  |  | $445 |
Regulatory Liabilities | Regulatory liabilities were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019
Tax-related |  | $746 |  |  |  | $836 |  |  |  | $334 |  |  |  | $351 |  |  |  | $412 |  |  |  | $485 |
Cost of removal obligations | 371 |  |  | 388 |  |  | 241 |  |  | 257 |  |  | 130 |  |  | 131 |
Electric transmission cost recovery | 62 |  |  | 88 |  |  | 30 |  |  | 51 |  |  | 32 |  |  | 37 |
Derivatives | 40 |  |  | 20 |  |  | 27 |  |  | 17 |  |  | 13 |  |  | 3 |
WPL’s West Riverside liquidated damages | 36 |  |  | — |  |  | — |  |  | — |  |  | 36 |  |  | — |
Commodity cost recovery | 22 |  |  | 24 |  |  | 19 |  |  | 9 |  |  | 3 |  |  | 15 |
WPL’s earnings sharing mechanism | 22 |  |  | 22 |  |  | — |  |  | — |  |  | 22 |  |  | 22 |
Other | 52 |  |  | 46 |  |  | 40 |  |  | 30 |  |  | 12 |  |  | 16 |
|  | $1,351 |  |  |  | $1,424 |  |  |  | $691 |  |  |  | $715 |  |  |  | $660 |  |  |  | $709 |
WPL [Member] |
Regulatory Assets [Line Items] |
Regulatory Assets | Regulatory assets were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019
Tax-related |  | $877 |  |  |  | $818 |  |  |  | $829 |  |  |  | $777 |  |  |  | $48 |  |  |  | $41 |
Pension and OPEB costs | 492 |  |  | 524 |  |  | 247 |  |  | 263 |  |  | 245 |  |  | 261 |
Assets retired early | 118 |  |  | 134 |  |  | 79 |  |  | 88 |  |  | 39 |  |  | 46 |
Asset retirement obligations | 115 |  |  | 112 |  |  | 79 |  |  | 76 |  |  | 36 |  |  | 36 |
IPL’s DAEC PPA amendment | 110 |  |  | 108 |  |  | 110 |  |  | 108 |  |  | — |  |  | — |
Derivatives | 20 |  |  | 39 |  |  | 8 |  |  | 18 |  |  | 12 |  |  | 21 |
Emission allowances | 19 |  |  | 21 |  |  | 19 |  |  | 21 |  |  | — |  |  | — |
Other | 85 |  |  | 89 |  |  | 47 |  |  | 49 |  |  | 38 |  |  | 40 |
|  | $1,836 |  |  |  | $1,845 |  |  |  | $1,418 |  |  |  | $1,400 |  |  |  | $418 |  |  |  | $445 |
Regulatory Liabilities | Regulatory liabilities were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019
Tax-related |  | $746 |  |  |  | $836 |  |  |  | $334 |  |  |  | $351 |  |  |  | $412 |  |  |  | $485 |
Cost of removal obligations | 371 |  |  | 388 |  |  | 241 |  |  | 257 |  |  | 130 |  |  | 131 |
Electric transmission cost recovery | 62 |  |  | 88 |  |  | 30 |  |  | 51 |  |  | 32 |  |  | 37 |
Derivatives | 40 |  |  | 20 |  |  | 27 |  |  | 17 |  |  | 13 |  |  | 3 |
WPL’s West Riverside liquidated damages | 36 |  |  | — |  |  | — |  |  | — |  |  | 36 |  |  | — |
Commodity cost recovery | 22 |  |  | 24 |  |  | 19 |  |  | 9 |  |  | 3 |  |  | 15 |
WPL’s earnings sharing mechanism | 22 |  |  | 22 |  |  | — |  |  | — |  |  | 22 |  |  | 22 |
Other | 52 |  |  | 46 |  |  | 40 |  |  | 30 |  |  | 12 |  |  | 16 |
|  | $1,351 |  |  |  | $1,424 |  |  |  | $691 |  |  |  | $715 |  |  |  | $660 |  |  |  | $709 |

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