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Regulatory Matters | 9 Months Ended
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Sep. 30, 2019
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
| 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 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 |
Assets Retired Early - Upon completion of the phased installation of advanced metering infrastructure, IPL retired certain analog electric meters in September 2019 and reclassified the $36 million remaining net book value of these meters from property, plant and equipment to a regulatory asset on Alliant Energy’s and IPL’s balance sheets. Recovery of these retired meters is included in the settlement agreement for IPL’s current retail electric base rate increase, and the IUB will decide on the recovery of these assets with the current retail electric rate review decision. IPL’s DAEC PPA Amendment - In January 2019, IPL incurred an obligation to make a September 2020 buyout payment of $110 million in exchange for shortening the term of IPL’s DAEC nuclear generation PPA by 5 years. The IUB approved placing the buyout payment in a regulatory asset account, which will be recovered from IPL’s retail customers over a 5-year period following the payment. The offsetting obligation has been discounted and is recorded in “Other current liabilities” on Alliant Energy’s and IPL’s balance sheets. Utility Rate Reviews IPL’s Retail Electric Rate Review (2020 Forward-looking Test Period) - In March 2019, IPL filed a request with the IUB to increase annual electric base rates for its Iowa retail electric customers based on a 2020 forward-looking Test Period. The key drivers for IPL’s request included recovery of capital projects, including new wind generation. IPL concurrently filed for interim retail electric rates based on 2018 historical data as adjusted for certain known and measurable changes occurring in the first quarter of 2019. An interim retail electric base rate increase of $90 million, on an annual basis, was implemented effective April 1, 2019. Implementing interim rates does not require regulatory approval; however, interim rates are subject to refund pending the IUB’s final rate review decision. In October 2019, IPL reached a partial, non-unanimous settlement agreement with intervenor groups for an annual retail electric base rate increase of $127 million. The agreement includes both the recovery of and a return on IPL’s early retired EGUs, and the recovery of IPL’s retired analog electric meters. The settlement agreement also includes IPL providing billing credits over a 12-month period beginning with final rates, including $27 million of excess deferred taxes resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform and $8 million from a partial refund of interim rates implemented in 2019. The IUB generally must decide on requests for retail rate changes within 10 months of the date of the application for which changes are filed. IPL currently expects a final decision, including a decision on the settlement agreement, from the IUB in the fourth quarter of 2019 with final rates effective in the first quarter of 2020. IPL’s Retail Gas Rate Review (2020 Forward-looking Test Period) - In March 2019, IPL filed a request with the IUB to increase annual gas base rates for its Iowa retail gas customers based on a 2020 forward-looking Test Period. The key drivers for IPL’s request included recovery of capital projects. In October 2019, IPL reached a unanimous settlement agreement with intervenor groups for an annual retail gas base rate increase of $12 million. IPL currently expects a decision, including a decision on the settlement agreement, from the IUB in the fourth quarter of 2019 with final rates effective in the first quarter of 2020.
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
| 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 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 |
Assets Retired Early - Upon completion of the phased installation of advanced metering infrastructure, IPL retired certain analog electric meters in September 2019 and reclassified the $36 million remaining net book value of these meters from property, plant and equipment to a regulatory asset on Alliant Energy’s and IPL’s balance sheets. Recovery of these retired meters is included in the settlement agreement for IPL’s current retail electric base rate increase, and the IUB will decide on the recovery of these assets with the current retail electric rate review decision. IPL’s DAEC PPA Amendment - In January 2019, IPL incurred an obligation to make a September 2020 buyout payment of $110 million in exchange for shortening the term of IPL’s DAEC nuclear generation PPA by 5 years. The IUB approved placing the buyout payment in a regulatory asset account, which will be recovered from IPL’s retail customers over a 5-year period following the payment. The offsetting obligation has been discounted and is recorded in “Other current liabilities” on Alliant Energy’s and IPL’s balance sheets. Utility Rate Reviews IPL’s Retail Electric Rate Review (2020 Forward-looking Test Period) - In March 2019, IPL filed a request with the IUB to increase annual electric base rates for its Iowa retail electric customers based on a 2020 forward-looking Test Period. The key drivers for IPL’s request included recovery of capital projects, including new wind generation. IPL concurrently filed for interim retail electric rates based on 2018 historical data as adjusted for certain known and measurable changes occurring in the first quarter of 2019. An interim retail electric base rate increase of $90 million, on an annual basis, was implemented effective April 1, 2019. Implementing interim rates does not require regulatory approval; however, interim rates are subject to refund pending the IUB’s final rate review decision. In October 2019, IPL reached a partial, non-unanimous settlement agreement with intervenor groups for an annual retail electric base rate increase of $127 million. The agreement includes both the recovery of and a return on IPL’s early retired EGUs, and the recovery of IPL’s retired analog electric meters. The settlement agreement also includes IPL providing billing credits over a 12-month period beginning with final rates, including $27 million of excess deferred taxes resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform and $8 million from a partial refund of interim rates implemented in 2019. The IUB generally must decide on requests for retail rate changes within 10 months of the date of the application for which changes are filed. IPL currently expects a final decision, including a decision on the settlement agreement, from the IUB in the fourth quarter of 2019 with final rates effective in the first quarter of 2020. IPL’s Retail Gas Rate Review (2020 Forward-looking Test Period) - In March 2019, IPL filed a request with the IUB to increase annual gas base rates for its Iowa retail gas customers based on a 2020 forward-looking Test Period. The key drivers for IPL’s request included recovery of capital projects. In October 2019, IPL reached a unanimous settlement agreement with intervenor groups for an annual retail gas base rate increase of $12 million. IPL currently expects a decision, including a decision on the settlement agreement, from the IUB in the fourth quarter of 2019 with final rates effective in the first quarter of 2020.
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
| 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 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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