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v3.19.3

Regulatory Matters (Tables) | 9 Months Ended
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Sep. 30, 2019
Regulatory Assets [Line Items] |
Regulatory Assets | Regulatory assets were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2019 |  | December 31, 2018 |  | September 30, 2019 |  | December 31, 2018 |  | September 30, 2019 |  | December 31, 2018
Tax-related |  | $825.2 |  |  |  | $820.6 |  |  |  | $787.2 |  |  |  | $783.1 |  |  |  | $38.0 |  |  |  | $37.5 |
Pension and OPEB costs | 513.1 |  |  | 542.3 |  |  | 260.0 |  |  | 274.0 |  |  | 253.1 |  |  | 268.3 |
Assets retired early | 138.7 |  |  | 111.6 |  |  | 90.1 |  |  | 55.4 |  |  | 48.6 |  |  | 56.2 |
Asset retirement obligations | 110.7 |  |  | 110.8 |  |  | 75.2 |  |  | 76.3 |  |  | 35.5 |  |  | 34.5 |
IPL’s DAEC PPA amendment | 107.7 |  |  | — |  |  | 107.7 |  |  | — |  |  | — |  |  | — |
Derivatives | 34.0 |  |  | 28.0 |  |  | 15.0 |  |  | 15.1 |  |  | 19.0 |  |  | 12.9 |
Emission allowances | 21.7 |  |  | 23.6 |  |  | 21.7 |  |  | 23.6 |  |  | — |  |  | — |
Other | 88.9 |  |  | 100.4 |  |  | 47.1 |  |  | 51.5 |  |  | 41.8 |  |  | 48.9 |
|  | $1,840.0 |  |  |  | $1,737.3 |  |  |  | $1,404.0 |  |  |  | $1,279.0 |  |  |  | $436.0 |  |  |  | $458.3 |
Regulatory Liabilities | Regulatory liabilities were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2019 |  | December 31, 2018 |  | September 30, 2019 |  | December 31, 2018 |  | September 30, 2019 |  | December 31, 2018
Tax-related |  | $851.4 |  |  |  | $890.6 |  |  |  | $365.0 |  |  |  | $390.1 |  |  |  | $486.4 |  |  |  | $500.5 |
Cost of removal obligations | 390.9 |  |  | 401.2 |  |  | 261.0 |  |  | 273.3 |  |  | 129.9 |  |  | 127.9 |
Electric transmission cost recovery | 89.8 |  |  | 104.0 |  |  | 48.0 |  |  | 47.7 |  |  | 41.8 |  |  | 56.3 |
Commodity cost recovery | 29.1 |  |  | 16.8 |  |  | 16.7 |  |  | 11.9 |  |  | 12.4 |  |  | 4.9 |
WPL’s earnings sharing mechanism | 21.8 |  |  | 25.4 |  |  | — |  |  | — |  |  | 21.8 |  |  | 25.4 |
Derivatives | 20.8 |  |  | 18.5 |  |  | 16.9 |  |  | 10.2 |  |  | 3.9 |  |  | 8.3 |
Other | 47.2 |  |  | 36.7 |  |  | 26.0 |  |  | 21.7 |  |  | 21.2 |  |  | 15.0 |
|  | $1,451.0 |  |  |  | $1,493.2 |  |  |  | $733.6 |  |  |  | $754.9 |  |  |  | $717.4 |  |  |  | $738.3 |
IPL [Member] |
Regulatory Assets [Line Items] |
Regulatory Assets | Regulatory assets were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2019 |  | December 31, 2018 |  | September 30, 2019 |  | December 31, 2018 |  | September 30, 2019 |  | December 31, 2018
Tax-related |  | $825.2 |  |  |  | $820.6 |  |  |  | $787.2 |  |  |  | $783.1 |  |  |  | $38.0 |  |  |  | $37.5 |
Pension and OPEB costs | 513.1 |  |  | 542.3 |  |  | 260.0 |  |  | 274.0 |  |  | 253.1 |  |  | 268.3 |
Assets retired early | 138.7 |  |  | 111.6 |  |  | 90.1 |  |  | 55.4 |  |  | 48.6 |  |  | 56.2 |
Asset retirement obligations | 110.7 |  |  | 110.8 |  |  | 75.2 |  |  | 76.3 |  |  | 35.5 |  |  | 34.5 |
IPL’s DAEC PPA amendment | 107.7 |  |  | — |  |  | 107.7 |  |  | — |  |  | — |  |  | — |
Derivatives | 34.0 |  |  | 28.0 |  |  | 15.0 |  |  | 15.1 |  |  | 19.0 |  |  | 12.9 |
Emission allowances | 21.7 |  |  | 23.6 |  |  | 21.7 |  |  | 23.6 |  |  | — |  |  | — |
Other | 88.9 |  |  | 100.4 |  |  | 47.1 |  |  | 51.5 |  |  | 41.8 |  |  | 48.9 |
|  | $1,840.0 |  |  |  | $1,737.3 |  |  |  | $1,404.0 |  |  |  | $1,279.0 |  |  |  | $436.0 |  |  |  | $458.3 |
Regulatory Liabilities | Regulatory liabilities were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2019 |  | December 31, 2018 |  | September 30, 2019 |  | December 31, 2018 |  | September 30, 2019 |  | December 31, 2018
Tax-related |  | $851.4 |  |  |  | $890.6 |  |  |  | $365.0 |  |  |  | $390.1 |  |  |  | $486.4 |  |  |  | $500.5 |
Cost of removal obligations | 390.9 |  |  | 401.2 |  |  | 261.0 |  |  | 273.3 |  |  | 129.9 |  |  | 127.9 |
Electric transmission cost recovery | 89.8 |  |  | 104.0 |  |  | 48.0 |  |  | 47.7 |  |  | 41.8 |  |  | 56.3 |
Commodity cost recovery | 29.1 |  |  | 16.8 |  |  | 16.7 |  |  | 11.9 |  |  | 12.4 |  |  | 4.9 |
WPL’s earnings sharing mechanism | 21.8 |  |  | 25.4 |  |  | — |  |  | — |  |  | 21.8 |  |  | 25.4 |
Derivatives | 20.8 |  |  | 18.5 |  |  | 16.9 |  |  | 10.2 |  |  | 3.9 |  |  | 8.3 |
Other | 47.2 |  |  | 36.7 |  |  | 26.0 |  |  | 21.7 |  |  | 21.2 |  |  | 15.0 |
|  | $1,451.0 |  |  |  | $1,493.2 |  |  |  | $733.6 |  |  |  | $754.9 |  |  |  | $717.4 |  |  |  | $738.3 |
WPL [Member] |
Regulatory Assets [Line Items] |
Regulatory Assets | Regulatory assets were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2019 |  | December 31, 2018 |  | September 30, 2019 |  | December 31, 2018 |  | September 30, 2019 |  | December 31, 2018
Tax-related |  | $825.2 |  |  |  | $820.6 |  |  |  | $787.2 |  |  |  | $783.1 |  |  |  | $38.0 |  |  |  | $37.5 |
Pension and OPEB costs | 513.1 |  |  | 542.3 |  |  | 260.0 |  |  | 274.0 |  |  | 253.1 |  |  | 268.3 |
Assets retired early | 138.7 |  |  | 111.6 |  |  | 90.1 |  |  | 55.4 |  |  | 48.6 |  |  | 56.2 |
Asset retirement obligations | 110.7 |  |  | 110.8 |  |  | 75.2 |  |  | 76.3 |  |  | 35.5 |  |  | 34.5 |
IPL’s DAEC PPA amendment | 107.7 |  |  | — |  |  | 107.7 |  |  | — |  |  | — |  |  | — |
Derivatives | 34.0 |  |  | 28.0 |  |  | 15.0 |  |  | 15.1 |  |  | 19.0 |  |  | 12.9 |
Emission allowances | 21.7 |  |  | 23.6 |  |  | 21.7 |  |  | 23.6 |  |  | — |  |  | — |
Other | 88.9 |  |  | 100.4 |  |  | 47.1 |  |  | 51.5 |  |  | 41.8 |  |  | 48.9 |
|  | $1,840.0 |  |  |  | $1,737.3 |  |  |  | $1,404.0 |  |  |  | $1,279.0 |  |  |  | $436.0 |  |  |  | $458.3 |
Regulatory Liabilities | Regulatory liabilities were comprised of the following items (in millions):
| Alliant Energy |  | IPL |  | WPL
| September 30, 2019 |  | December 31, 2018 |  | September 30, 2019 |  | December 31, 2018 |  | September 30, 2019 |  | December 31, 2018
Tax-related |  | $851.4 |  |  |  | $890.6 |  |  |  | $365.0 |  |  |  | $390.1 |  |  |  | $486.4 |  |  |  | $500.5 |
Cost of removal obligations | 390.9 |  |  | 401.2 |  |  | 261.0 |  |  | 273.3 |  |  | 129.9 |  |  | 127.9 |
Electric transmission cost recovery | 89.8 |  |  | 104.0 |  |  | 48.0 |  |  | 47.7 |  |  | 41.8 |  |  | 56.3 |
Commodity cost recovery | 29.1 |  |  | 16.8 |  |  | 16.7 |  |  | 11.9 |  |  | 12.4 |  |  | 4.9 |
WPL’s earnings sharing mechanism | 21.8 |  |  | 25.4 |  |  | — |  |  | — |  |  | 21.8 |  |  | 25.4 |
Derivatives | 20.8 |  |  | 18.5 |  |  | 16.9 |  |  | 10.2 |  |  | 3.9 |  |  | 8.3 |
Other | 47.2 |  |  | 36.7 |  |  | 26.0 |  |  | 21.7 |  |  | 21.2 |  |  | 15.0 |
|  | $1,451.0 |  |  |  | $1,493.2 |  |  |  | $733.6 |  |  |  | $754.9 |  |  |  | $717.4 |  |  |  | $738.3 |

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