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Property, Plant and Equipment | 12 Months Ended
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Dec. 31, 2018
Property, Plant and Equipment [Line Items] |
Property, Plant and Equipment | PROPERTY, PLANT AND EQUIPMENT At December 31, details of property, plant and equipment on the balance sheets were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2018 |  | 2017 |  | 2018 |  | 2017 |  | 2018 |  | 2017
Utility: |  |  |  |  |  |  |  |  |  |  |
Electric plant: |  |  |  |  |  |  |  |  |  |  |
Generation in service |  | $6,800.6 |  |  |  | $6,655.3 |  |  |  | $3,610.4 |  |  |  | $3,715.9 |  |  |  | $3,190.2 |  |  |  | $2,939.4 |
Distribution in service | 5,452.2 |  |  | 5,123.5 |  |  | 3,023.7 |  |  | 2,820.9 |  |  | 2,428.5 |  |  | 2,302.6 |
Other in service | 410.8 |  |  | 425.1 |  |  | 260.4 |  |  | 282.3 |  |  | 150.4 |  |  | 142.8 |
Anticipated to be retired early (a) | — |  |  | 93.0 |  |  | — |  |  | — |  |  | — |  |  | 93.0 |
Total electric plant | 12,663.6 |  |  | 12,296.9 |  |  | 6,894.5 |  |  | 6,819.1 |  |  | 5,769.1 |  |  | 5,477.8 |
Gas plant in service | 1,387.6 |  |  | 1,244.0 |  |  | 763.1 |  |  | 654.8 |  |  | 624.5 |  |  | 589.2 |
Other plant in service | 513.2 |  |  | 571.9 |  |  | 322.4 |  |  | 333.4 |  |  | 190.8 |  |  | 238.5 |
Accumulated depreciation | (4,314.6 | ) |  | (4,283.1 | ) |  | (2,294.7 | ) |  | (2,311.0 | ) |  | (2,019.9 | ) |  | (1,972.1 | )
Net plant | 10,249.8 |  |  | 9,829.7 |  |  | 5,685.3 |  |  | 5,496.3 |  |  | 4,564.5 |  |  | 4,333.4 |
Leased Sheboygan Falls Energy Facility, net (b) | — |  |  | — |  |  | — |  |  | — |  |  | 38.1 |  |  | 46.2 |
Construction work in progress | 1,774.8 |  |  | 962.2 |  |  | 1,091.2 |  |  | 424.4 |  |  | 683.6 |  |  | 537.8 |
Other, net | 6.1 |  |  | 6.0 |  |  | 5.0 |  |  | 5.5 |  |  | 1.1 |  |  | 0.5 |
Total utility | 12,030.7 |  |  | 10,797.9 |  |  | 6,781.5 |  |  | 5,926.2 |  |  | 5,287.3 |  |  | 4,917.9 |
Non-utility and other: |  |  |  |  |  |  |  |  |  |  |
Non-utility Generation, net (c) | 86.9 |  |  | 90.9 |  |  | — |  |  | — |  |  | — |  |  | — |
Corporate Services and other, net (d) | 344.8 |  |  | 345.7 |  |  | — |  |  | — |  |  | — |  |  | — |
Total non-utility and other | 431.7 |  |  | 436.6 |  |  | — |  |  | — |  |  | — |  |  | — |
Total property, plant and equipment |  | $12,462.4 |  |  |  | $11,234.5 |  |  |  | $6,781.5 |  |  |  | $5,926.2 |  |  |  | $5,287.3 |  |  |  | $4,917.9 |
(a) | In 2018, WPL retired Edgewater Unit 4 and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and WPL’s balance sheets.
(b) | Less accumulated amortization of $82.8 million and $77.6 million for WPL as of December 31, 2018 and 2017, respectively. The Sheboygan Falls Energy Facility is eliminated from WPL upon consolidation and is included in the “Non-utility Generation, net” line within Alliant Energy’s consolidated property, plant and equipment.
(c) | Less accumulated depreciation of $54.5 million and $50.5 million for Alliant Energy as of December 31, 2018 and 2017, respectively.
(d) | Less accumulated depreciation of $167.5 million and $285.6 million for Alliant Energy as of December 31, 2018 and 2017, respectively.
Generation in Service - WPL’s Acquisition of Forward Wind Energy Center - In 2018, WPL, along with WPSC and MGE, received approval from the PSCW and FERC to acquire a partial ownership interest in the assets of FWEC, which is a 129 MW wind farm located in Wisconsin. In April 2018, WPL acquired 55 MW of the FWEC wind farm for approximately $74 million. WPL, WPSC and MGE had been receiving electricity from the FWEC wind farm under PPAs since FWEC began commercial operations in 2008. Upon completion of the acquisitions, such PPAs terminated. As of the closing date, the estimated fair value of the assets purchased and the liabilities assumed by WPL were as follows (in millions):
Property, plant and equipment, net |  | $81 |
Liabilities | 7 |
Net assets acquired |  | $74 |
Franklin County Wind Farm - In 2016, based on an evaluation of the strategic options for the Franklin County wind farm, Alliant Energy concluded it was probable the Franklin County wind farm would be transferred to IPL. As a result, Alliant Energy performed an impairment analysis of such assets and recorded non-cash, pre-tax asset valuation charges of $86 million (after-tax charges of $51 million, or $0.23 per share) in 2016. Alliant Energy recorded such charges as a reduction to property, plant and equipment on its balance sheet and charges to “Asset valuation charges for Franklin County wind farm” in its income statement in 2016. In April 2017, the Franklin County wind farm was transferred from AEF to IPL as approved by a February 2017 FERC order. IPL’s purchase price, including certain transaction-related costs, was $32 million. As of the closing date, the estimated fair values of the assets purchased and liabilities assumed by IPL were as follows (in millions):
Electric plant in service |  | $40 |
Current assets | 2 |
Total assets acquired | 42 |
Other liabilities | 10 |
Net assets acquired |  | $32 |
AFUDC - AFUDC represents costs to finance construction additions, including a return on equity component and cost of debt component as required by regulatory accounting. The concurrent credit for the amount of AFUDC capitalized is recorded as “Allowance for funds used during construction” in the income statements. The amount of AFUDC generated by equity and debt components was as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2018 |  | 2017 |  | 2016 |  | 2018 |  | 2017 |  | 2016 |  | 2018 |  | 2017 |  | 2016
Equity |  | $51.4 |  |  |  | $33.6 |  |  |  | $42.3 |  |  |  | $28.6 |  |  |  | $21.1 |  |  |  | $35.2 |  |  |  | $22.8 |  |  |  | $12.5 |  |  |  | $7.1 |
Debt | 24.2 |  |  | 16.1 |  |  | 20.2 |  |  | 13.6 |  |  | 10.3 |  |  | 16.8 |  |  | 10.6 |  |  | 5.8 |  |  | 3.4 |
|  | $75.6 |  |  |  | $49.7 |  |  |  | $62.5 |  |  |  | $42.2 |  |  |  | $31.4 |  |  |  | $52.0 |  |  |  | $33.4 |  |  |  | $18.3 |  |  |  | $10.5 |
Non-utility and Other - The non-utility and other property, plant and equipment recorded on Alliant Energy’s balance sheets includes the following: Non-utility Generation - The Sheboygan Falls Energy Facility was placed into service in 2005 and is depreciated using the straight-line method over a 35-year period. As of December 31, 2018, Alliant Energy recorded $87 million on its balance sheet related to the Sheboygan Falls Energy Facility. Corporate Services and Other - Property, plant and equipment related to Corporate Services includes a customer billing and information system for IPL and WPL and other computer software, and the corporate headquarters building located in Madison, Wisconsin. The customer billing and information system is amortized using the straight-line method over a 12-year period. The majority of the remaining software is amortized over a 5-year period. Property, plant and equipment related to Transportation includes a short-line railway in Iowa and a barge terminal on the Mississippi River. The Corporate Services and Other property, plant and equipment is depreciated using the straight-line method over periods ranging from 5 to 30 years.
IPL [Member] |
Property, Plant and Equipment [Line Items] |
Property, Plant and Equipment | PROPERTY, PLANT AND EQUIPMENT At December 31, details of property, plant and equipment on the balance sheets were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2018 |  | 2017 |  | 2018 |  | 2017 |  | 2018 |  | 2017
Utility: |  |  |  |  |  |  |  |  |  |  |
Electric plant: |  |  |  |  |  |  |  |  |  |  |
Generation in service |  | $6,800.6 |  |  |  | $6,655.3 |  |  |  | $3,610.4 |  |  |  | $3,715.9 |  |  |  | $3,190.2 |  |  |  | $2,939.4 |
Distribution in service | 5,452.2 |  |  | 5,123.5 |  |  | 3,023.7 |  |  | 2,820.9 |  |  | 2,428.5 |  |  | 2,302.6 |
Other in service | 410.8 |  |  | 425.1 |  |  | 260.4 |  |  | 282.3 |  |  | 150.4 |  |  | 142.8 |
Anticipated to be retired early (a) | — |  |  | 93.0 |  |  | — |  |  | — |  |  | — |  |  | 93.0 |
Total electric plant | 12,663.6 |  |  | 12,296.9 |  |  | 6,894.5 |  |  | 6,819.1 |  |  | 5,769.1 |  |  | 5,477.8 |
Gas plant in service | 1,387.6 |  |  | 1,244.0 |  |  | 763.1 |  |  | 654.8 |  |  | 624.5 |  |  | 589.2 |
Other plant in service | 513.2 |  |  | 571.9 |  |  | 322.4 |  |  | 333.4 |  |  | 190.8 |  |  | 238.5 |
Accumulated depreciation | (4,314.6 | ) |  | (4,283.1 | ) |  | (2,294.7 | ) |  | (2,311.0 | ) |  | (2,019.9 | ) |  | (1,972.1 | )
Net plant | 10,249.8 |  |  | 9,829.7 |  |  | 5,685.3 |  |  | 5,496.3 |  |  | 4,564.5 |  |  | 4,333.4 |
Leased Sheboygan Falls Energy Facility, net (b) | — |  |  | — |  |  | — |  |  | — |  |  | 38.1 |  |  | 46.2 |
Construction work in progress | 1,774.8 |  |  | 962.2 |  |  | 1,091.2 |  |  | 424.4 |  |  | 683.6 |  |  | 537.8 |
Other, net | 6.1 |  |  | 6.0 |  |  | 5.0 |  |  | 5.5 |  |  | 1.1 |  |  | 0.5 |
Total utility | 12,030.7 |  |  | 10,797.9 |  |  | 6,781.5 |  |  | 5,926.2 |  |  | 5,287.3 |  |  | 4,917.9 |
Non-utility and other: |  |  |  |  |  |  |  |  |  |  |
Non-utility Generation, net (c) | 86.9 |  |  | 90.9 |  |  | — |  |  | — |  |  | — |  |  | — |
Corporate Services and other, net (d) | 344.8 |  |  | 345.7 |  |  | — |  |  | — |  |  | — |  |  | — |
Total non-utility and other | 431.7 |  |  | 436.6 |  |  | — |  |  | — |  |  | — |  |  | — |
Total property, plant and equipment |  | $12,462.4 |  |  |  | $11,234.5 |  |  |  | $6,781.5 |  |  |  | $5,926.2 |  |  |  | $5,287.3 |  |  |  | $4,917.9 |
(a) | In 2018, WPL retired Edgewater Unit 4 and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and WPL’s balance sheets.
(b) | Less accumulated amortization of $82.8 million and $77.6 million for WPL as of December 31, 2018 and 2017, respectively. The Sheboygan Falls Energy Facility is eliminated from WPL upon consolidation and is included in the “Non-utility Generation, net” line within Alliant Energy’s consolidated property, plant and equipment.
(c) | Less accumulated depreciation of $54.5 million and $50.5 million for Alliant Energy as of December 31, 2018 and 2017, respectively.
(d) | Less accumulated depreciation of $167.5 million and $285.6 million for Alliant Energy as of December 31, 2018 and 2017, respectively.
Generation in Service - WPL’s Acquisition of Forward Wind Energy Center - In 2018, WPL, along with WPSC and MGE, received approval from the PSCW and FERC to acquire a partial ownership interest in the assets of FWEC, which is a 129 MW wind farm located in Wisconsin. In April 2018, WPL acquired 55 MW of the FWEC wind farm for approximately $74 million. WPL, WPSC and MGE had been receiving electricity from the FWEC wind farm under PPAs since FWEC began commercial operations in 2008. Upon completion of the acquisitions, such PPAs terminated. As of the closing date, the estimated fair value of the assets purchased and the liabilities assumed by WPL were as follows (in millions):
Property, plant and equipment, net |  | $81 |
Liabilities | 7 |
Net assets acquired |  | $74 |
Franklin County Wind Farm - In 2016, based on an evaluation of the strategic options for the Franklin County wind farm, Alliant Energy concluded it was probable the Franklin County wind farm would be transferred to IPL. As a result, Alliant Energy performed an impairment analysis of such assets and recorded non-cash, pre-tax asset valuation charges of $86 million (after-tax charges of $51 million, or $0.23 per share) in 2016. Alliant Energy recorded such charges as a reduction to property, plant and equipment on its balance sheet and charges to “Asset valuation charges for Franklin County wind farm” in its income statement in 2016. In April 2017, the Franklin County wind farm was transferred from AEF to IPL as approved by a February 2017 FERC order. IPL’s purchase price, including certain transaction-related costs, was $32 million. As of the closing date, the estimated fair values of the assets purchased and liabilities assumed by IPL were as follows (in millions):
Electric plant in service |  | $40 |
Current assets | 2 |
Total assets acquired | 42 |
Other liabilities | 10 |
Net assets acquired |  | $32 |
AFUDC - AFUDC represents costs to finance construction additions, including a return on equity component and cost of debt component as required by regulatory accounting. The concurrent credit for the amount of AFUDC capitalized is recorded as “Allowance for funds used during construction” in the income statements. The amount of AFUDC generated by equity and debt components was as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2018 |  | 2017 |  | 2016 |  | 2018 |  | 2017 |  | 2016 |  | 2018 |  | 2017 |  | 2016
Equity |  | $51.4 |  |  |  | $33.6 |  |  |  | $42.3 |  |  |  | $28.6 |  |  |  | $21.1 |  |  |  | $35.2 |  |  |  | $22.8 |  |  |  | $12.5 |  |  |  | $7.1 |
Debt | 24.2 |  |  | 16.1 |  |  | 20.2 |  |  | 13.6 |  |  | 10.3 |  |  | 16.8 |  |  | 10.6 |  |  | 5.8 |  |  | 3.4 |
|  | $75.6 |  |  |  | $49.7 |  |  |  | $62.5 |  |  |  | $42.2 |  |  |  | $31.4 |  |  |  | $52.0 |  |  |  | $33.4 |  |  |  | $18.3 |  |  |  | $10.5 |
WPL [Member] |
Property, Plant and Equipment [Line Items] |
Property, Plant and Equipment | PROPERTY, PLANT AND EQUIPMENT At December 31, details of property, plant and equipment on the balance sheets were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2018 |  | 2017 |  | 2018 |  | 2017 |  | 2018 |  | 2017
Utility: |  |  |  |  |  |  |  |  |  |  |
Electric plant: |  |  |  |  |  |  |  |  |  |  |
Generation in service |  | $6,800.6 |  |  |  | $6,655.3 |  |  |  | $3,610.4 |  |  |  | $3,715.9 |  |  |  | $3,190.2 |  |  |  | $2,939.4 |
Distribution in service | 5,452.2 |  |  | 5,123.5 |  |  | 3,023.7 |  |  | 2,820.9 |  |  | 2,428.5 |  |  | 2,302.6 |
Other in service | 410.8 |  |  | 425.1 |  |  | 260.4 |  |  | 282.3 |  |  | 150.4 |  |  | 142.8 |
Anticipated to be retired early (a) | — |  |  | 93.0 |  |  | — |  |  | — |  |  | — |  |  | 93.0 |
Total electric plant | 12,663.6 |  |  | 12,296.9 |  |  | 6,894.5 |  |  | 6,819.1 |  |  | 5,769.1 |  |  | 5,477.8 |
Gas plant in service | 1,387.6 |  |  | 1,244.0 |  |  | 763.1 |  |  | 654.8 |  |  | 624.5 |  |  | 589.2 |
Other plant in service | 513.2 |  |  | 571.9 |  |  | 322.4 |  |  | 333.4 |  |  | 190.8 |  |  | 238.5 |
Accumulated depreciation | (4,314.6 | ) |  | (4,283.1 | ) |  | (2,294.7 | ) |  | (2,311.0 | ) |  | (2,019.9 | ) |  | (1,972.1 | )
Net plant | 10,249.8 |  |  | 9,829.7 |  |  | 5,685.3 |  |  | 5,496.3 |  |  | 4,564.5 |  |  | 4,333.4 |
Leased Sheboygan Falls Energy Facility, net (b) | — |  |  | — |  |  | — |  |  | — |  |  | 38.1 |  |  | 46.2 |
Construction work in progress | 1,774.8 |  |  | 962.2 |  |  | 1,091.2 |  |  | 424.4 |  |  | 683.6 |  |  | 537.8 |
Other, net | 6.1 |  |  | 6.0 |  |  | 5.0 |  |  | 5.5 |  |  | 1.1 |  |  | 0.5 |
Total utility | 12,030.7 |  |  | 10,797.9 |  |  | 6,781.5 |  |  | 5,926.2 |  |  | 5,287.3 |  |  | 4,917.9 |
Non-utility and other: |  |  |  |  |  |  |  |  |  |  |
Non-utility Generation, net (c) | 86.9 |  |  | 90.9 |  |  | — |  |  | — |  |  | — |  |  | — |
Corporate Services and other, net (d) | 344.8 |  |  | 345.7 |  |  | — |  |  | — |  |  | — |  |  | — |
Total non-utility and other | 431.7 |  |  | 436.6 |  |  | — |  |  | — |  |  | — |  |  | — |
Total property, plant and equipment |  | $12,462.4 |  |  |  | $11,234.5 |  |  |  | $6,781.5 |  |  |  | $5,926.2 |  |  |  | $5,287.3 |  |  |  | $4,917.9 |
(a) | In 2018, WPL retired Edgewater Unit 4 and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and WPL’s balance sheets.
(b) | Less accumulated amortization of $82.8 million and $77.6 million for WPL as of December 31, 2018 and 2017, respectively. The Sheboygan Falls Energy Facility is eliminated from WPL upon consolidation and is included in the “Non-utility Generation, net” line within Alliant Energy’s consolidated property, plant and equipment.
(c) | Less accumulated depreciation of $54.5 million and $50.5 million for Alliant Energy as of December 31, 2018 and 2017, respectively.
(d) | Less accumulated depreciation of $167.5 million and $285.6 million for Alliant Energy as of December 31, 2018 and 2017, respectively.
Generation in Service - WPL’s Acquisition of Forward Wind Energy Center - In 2018, WPL, along with WPSC and MGE, received approval from the PSCW and FERC to acquire a partial ownership interest in the assets of FWEC, which is a 129 MW wind farm located in Wisconsin. In April 2018, WPL acquired 55 MW of the FWEC wind farm for approximately $74 million. WPL, WPSC and MGE had been receiving electricity from the FWEC wind farm under PPAs since FWEC began commercial operations in 2008. Upon completion of the acquisitions, such PPAs terminated. As of the closing date, the estimated fair value of the assets purchased and the liabilities assumed by WPL were as follows (in millions):
Property, plant and equipment, net |  | $81 |
Liabilities | 7 |
Net assets acquired |  | $74 |
Franklin County Wind Farm - In 2016, based on an evaluation of the strategic options for the Franklin County wind farm, Alliant Energy concluded it was probable the Franklin County wind farm would be transferred to IPL. As a result, Alliant Energy performed an impairment analysis of such assets and recorded non-cash, pre-tax asset valuation charges of $86 million (after-tax charges of $51 million, or $0.23 per share) in 2016. Alliant Energy recorded such charges as a reduction to property, plant and equipment on its balance sheet and charges to “Asset valuation charges for Franklin County wind farm” in its income statement in 2016. In April 2017, the Franklin County wind farm was transferred from AEF to IPL as approved by a February 2017 FERC order. IPL’s purchase price, including certain transaction-related costs, was $32 million. As of the closing date, the estimated fair values of the assets purchased and liabilities assumed by IPL were as follows (in millions):
Electric plant in service |  | $40 |
Current assets | 2 |
Total assets acquired | 42 |
Other liabilities | 10 |
Net assets acquired |  | $32 |
AFUDC - AFUDC represents costs to finance construction additions, including a return on equity component and cost of debt component as required by regulatory accounting. The concurrent credit for the amount of AFUDC capitalized is recorded as “Allowance for funds used during construction” in the income statements. The amount of AFUDC generated by equity and debt components was as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2018 |  | 2017 |  | 2016 |  | 2018 |  | 2017 |  | 2016 |  | 2018 |  | 2017 |  | 2016
Equity |  | $51.4 |  |  |  | $33.6 |  |  |  | $42.3 |  |  |  | $28.6 |  |  |  | $21.1 |  |  |  | $35.2 |  |  |  | $22.8 |  |  |  | $12.5 |  |  |  | $7.1 |
Debt | 24.2 |  |  | 16.1 |  |  | 20.2 |  |  | 13.6 |  |  | 10.3 |  |  | 16.8 |  |  | 10.6 |  |  | 5.8 |  |  | 3.4 |
|  | $75.6 |  |  |  | $49.7 |  |  |  | $62.5 |  |  |  | $42.2 |  |  |  | $31.4 |  |  |  | $52.0 |  |  |  | $33.4 |  |  |  | $18.3 |  |  |  | $10.5 |

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- Definition The entire disclosure for long-lived, physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, accounting policies and methodology, roll forwards, depreciation, depletion and amortization expense, including composite depreciation, accumulated depreciation, depletion and amortization expense, useful lives and method used, income statement disclosures, assets held for sale and public utility disclosures. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -URI http://asc.fasb.org/topic&trid=2155823 + Details
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