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Property, Plant and Equipment | 12 Months Ended
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Dec. 31, 2020
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
| 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Utility: |  |  |  |  |  |  |  |  |  |  |
Electric plant: |  |  |  |  |  |  |  |  |  |  |
Generation in service | $8,222 |  |  | $7,625 |  |  | $4,884 |  |  | $4,432 |  |  | $3,338 |  |  | $3,193 |
Distribution in service | 6,216 |  |  | 5,783 |  |  | 3,470 |  |  | 3,190 |  |  | 2,746 |  |  | 2,593 |
Other in service | 536 |  |  | 457 |  |  | 358 |  |  | 299 |  |  | 178 |  |  | 158 |
Anticipated to be retired early (a) | 1,269 |  |  | — |  |  | 459 |  |  | — |  |  | 810 |  |  | — |
Total electric plant | 16,243 |  |  | 13,865 |  |  | 9,171 |  |  | 7,921 |  |  | 7,072 |  |  | 5,944 |
Gas plant in service | 1,563 |  |  | 1,463 |  |  | 844 |  |  | 802 |  |  | 719 |  |  | 661 |
Other plant in service | 534 |  |  | 520 |  |  | 354 |  |  | 345 |  |  | 180 |  |  | 175 |
Accumulated depreciation | (4,868) |  |  | (4,602) |  |  | (2,671) |  |  | (2,499) |  |  | (2,197) |  |  | (2,103) |
Net plant | 13,472 |  |  | 11,246 |  |  | 7,698 |  |  | 6,569 |  |  | 5,774 |  |  | 4,677 |
Leased Sheboygan Falls Energy Facility, net (b) | — |  |  | — |  |  | — |  |  | — |  |  | 27 |  |  | 32 |
Construction work in progress | 405 |  |  | 1,835 |  |  | 185 |  |  | 907 |  |  | 220 |  |  | 928 |
Other, net | 7 |  |  | 6 |  |  | 6 |  |  | 5 |  |  | 1 |  |  | 1 |
Total utility | 13,884 |  |  | 13,087 |  |  | 7,889 |  |  | 7,481 |  |  | 6,022 |  |  | 5,638 |
Non-utility and other: |  |  |  |  |  |  |  |  |  |  |
Non-utility Generation, net (c) | 79 |  |  | 83 |  |  | — |  |  | — |  |  | — |  |  | — |
Corporate Services and other, net (d) | 373 |  |  | 357 |  |  | — |  |  | — |  |  | — |  |  | — |
Total non-utility and other | 452 |  |  | 440 |  |  | — |  |  | — |  |  | — |  |  | — |
Total property, plant and equipment | $14,336 |  |  | $13,527 |  |  | $7,889 |  |  | $7,481 |  |  | $6,022 |  |  | $5,638 |
(a)In 2020, IPL and WPL received approval from MISO to retire Lansing and Edgewater Unit 5, respectively, and currently anticipate retiring these EGUs by the end of 2022. Alliant Energy and IPL concluded that Lansing, and Alliant Energy and WPL concluded that Edgewater Unit 5, met the criteria to be considered probable of abandonment as of December 31, 2020. IPL and WPL are currently allowed a full recovery of and a full return on its respective EGU from both its retail and wholesale customers. (b)Less accumulated amortization of $95 million and $89 million for WPL as of December 31, 2020 and 2019, respectively. The leased 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 $63 million and $59 million for Alliant Energy as of December 31, 2020 and 2019, respectively. (d)Less accumulated depreciation of $210 million and $172 million for Alliant Energy as of December 31, 2020 and 2019, respectively. 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
| 2020 |  | 2019 |  | 2018 |  | 2020 |  | 2019 |  | 2018 |  | 2020 |  | 2019 |  | 2018
Equity | $39 |  | $66 |  | $51 |  | $17 |  | $35 |  | $29 |  | $22 |  | $31 |  | $22
Debt | 16 |  | 27 |  | 25 |  | 7 |  | 15 |  | 13 |  | 9 |  | 12 |  | 12
| $55 |  | $93 |  | $76 |  | $24 |  | $50 |  | $42 |  | $31 |  | $43 |  | $34
Non-utility and Other - The non-utility and other property, plant and equipment recorded on Alliant Energy’s balance sheets include 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. Corporate Services and Other - Property, plant and equipment related to Corporate Services include 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. Other property, plant and equipment include Travero assets (a short-line railway in Iowa and a barge terminal on the Mississippi River). All Corporate Services and Other property, plant and equipment are 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
| 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Utility: |  |  |  |  |  |  |  |  |  |  |
Electric plant: |  |  |  |  |  |  |  |  |  |  |
Generation in service | $8,222 |  |  | $7,625 |  |  | $4,884 |  |  | $4,432 |  |  | $3,338 |  |  | $3,193 |
Distribution in service | 6,216 |  |  | 5,783 |  |  | 3,470 |  |  | 3,190 |  |  | 2,746 |  |  | 2,593 |
Other in service | 536 |  |  | 457 |  |  | 358 |  |  | 299 |  |  | 178 |  |  | 158 |
Anticipated to be retired early (a) | 1,269 |  |  | — |  |  | 459 |  |  | — |  |  | 810 |  |  | — |
Total electric plant | 16,243 |  |  | 13,865 |  |  | 9,171 |  |  | 7,921 |  |  | 7,072 |  |  | 5,944 |
Gas plant in service | 1,563 |  |  | 1,463 |  |  | 844 |  |  | 802 |  |  | 719 |  |  | 661 |
Other plant in service | 534 |  |  | 520 |  |  | 354 |  |  | 345 |  |  | 180 |  |  | 175 |
Accumulated depreciation | (4,868) |  |  | (4,602) |  |  | (2,671) |  |  | (2,499) |  |  | (2,197) |  |  | (2,103) |
Net plant | 13,472 |  |  | 11,246 |  |  | 7,698 |  |  | 6,569 |  |  | 5,774 |  |  | 4,677 |
Leased Sheboygan Falls Energy Facility, net (b) | — |  |  | — |  |  | — |  |  | — |  |  | 27 |  |  | 32 |
Construction work in progress | 405 |  |  | 1,835 |  |  | 185 |  |  | 907 |  |  | 220 |  |  | 928 |
Other, net | 7 |  |  | 6 |  |  | 6 |  |  | 5 |  |  | 1 |  |  | 1 |
Total utility | 13,884 |  |  | 13,087 |  |  | 7,889 |  |  | 7,481 |  |  | 6,022 |  |  | 5,638 |
Non-utility and other: |  |  |  |  |  |  |  |  |  |  |
Non-utility Generation, net (c) | 79 |  |  | 83 |  |  | — |  |  | — |  |  | — |  |  | — |
Corporate Services and other, net (d) | 373 |  |  | 357 |  |  | — |  |  | — |  |  | — |  |  | — |
Total non-utility and other | 452 |  |  | 440 |  |  | — |  |  | — |  |  | — |  |  | — |
Total property, plant and equipment | $14,336 |  |  | $13,527 |  |  | $7,889 |  |  | $7,481 |  |  | $6,022 |  |  | $5,638 |
(a)In 2020, IPL and WPL received approval from MISO to retire Lansing and Edgewater Unit 5, respectively, and currently anticipate retiring these EGUs by the end of 2022. Alliant Energy and IPL concluded that Lansing, and Alliant Energy and WPL concluded that Edgewater Unit 5, met the criteria to be considered probable of abandonment as of December 31, 2020. IPL and WPL are currently allowed a full recovery of and a full return on its respective EGU from both its retail and wholesale customers. (b)Less accumulated amortization of $95 million and $89 million for WPL as of December 31, 2020 and 2019, respectively. The leased 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 $63 million and $59 million for Alliant Energy as of December 31, 2020 and 2019, respectively. (d)Less accumulated depreciation of $210 million and $172 million for Alliant Energy as of December 31, 2020 and 2019, respectively. 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
| 2020 |  | 2019 |  | 2018 |  | 2020 |  | 2019 |  | 2018 |  | 2020 |  | 2019 |  | 2018
Equity | $39 |  | $66 |  | $51 |  | $17 |  | $35 |  | $29 |  | $22 |  | $31 |  | $22
Debt | 16 |  | 27 |  | 25 |  | 7 |  | 15 |  | 13 |  | 9 |  | 12 |  | 12
| $55 |  | $93 |  | $76 |  | $24 |  | $50 |  | $42 |  | $31 |  | $43 |  | $34
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
| 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Utility: |  |  |  |  |  |  |  |  |  |  |
Electric plant: |  |  |  |  |  |  |  |  |  |  |
Generation in service | $8,222 |  |  | $7,625 |  |  | $4,884 |  |  | $4,432 |  |  | $3,338 |  |  | $3,193 |
Distribution in service | 6,216 |  |  | 5,783 |  |  | 3,470 |  |  | 3,190 |  |  | 2,746 |  |  | 2,593 |
Other in service | 536 |  |  | 457 |  |  | 358 |  |  | 299 |  |  | 178 |  |  | 158 |
Anticipated to be retired early (a) | 1,269 |  |  | — |  |  | 459 |  |  | — |  |  | 810 |  |  | — |
Total electric plant | 16,243 |  |  | 13,865 |  |  | 9,171 |  |  | 7,921 |  |  | 7,072 |  |  | 5,944 |
Gas plant in service | 1,563 |  |  | 1,463 |  |  | 844 |  |  | 802 |  |  | 719 |  |  | 661 |
Other plant in service | 534 |  |  | 520 |  |  | 354 |  |  | 345 |  |  | 180 |  |  | 175 |
Accumulated depreciation | (4,868) |  |  | (4,602) |  |  | (2,671) |  |  | (2,499) |  |  | (2,197) |  |  | (2,103) |
Net plant | 13,472 |  |  | 11,246 |  |  | 7,698 |  |  | 6,569 |  |  | 5,774 |  |  | 4,677 |
Leased Sheboygan Falls Energy Facility, net (b) | — |  |  | — |  |  | — |  |  | — |  |  | 27 |  |  | 32 |
Construction work in progress | 405 |  |  | 1,835 |  |  | 185 |  |  | 907 |  |  | 220 |  |  | 928 |
Other, net | 7 |  |  | 6 |  |  | 6 |  |  | 5 |  |  | 1 |  |  | 1 |
Total utility | 13,884 |  |  | 13,087 |  |  | 7,889 |  |  | 7,481 |  |  | 6,022 |  |  | 5,638 |
Non-utility and other: |  |  |  |  |  |  |  |  |  |  |
Non-utility Generation, net (c) | 79 |  |  | 83 |  |  | — |  |  | — |  |  | — |  |  | — |
Corporate Services and other, net (d) | 373 |  |  | 357 |  |  | — |  |  | — |  |  | — |  |  | — |
Total non-utility and other | 452 |  |  | 440 |  |  | — |  |  | — |  |  | — |  |  | — |
Total property, plant and equipment | $14,336 |  |  | $13,527 |  |  | $7,889 |  |  | $7,481 |  |  | $6,022 |  |  | $5,638 |
(a)In 2020, IPL and WPL received approval from MISO to retire Lansing and Edgewater Unit 5, respectively, and currently anticipate retiring these EGUs by the end of 2022. Alliant Energy and IPL concluded that Lansing, and Alliant Energy and WPL concluded that Edgewater Unit 5, met the criteria to be considered probable of abandonment as of December 31, 2020. IPL and WPL are currently allowed a full recovery of and a full return on its respective EGU from both its retail and wholesale customers. (b)Less accumulated amortization of $95 million and $89 million for WPL as of December 31, 2020 and 2019, respectively. The leased 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 $63 million and $59 million for Alliant Energy as of December 31, 2020 and 2019, respectively. (d)Less accumulated depreciation of $210 million and $172 million for Alliant Energy as of December 31, 2020 and 2019, respectively. 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
| 2020 |  | 2019 |  | 2018 |  | 2020 |  | 2019 |  | 2018 |  | 2020 |  | 2019 |  | 2018
Equity | $39 |  | $66 |  | $51 |  | $17 |  | $35 |  | $29 |  | $22 |  | $31 |  | $22
Debt | 16 |  | 27 |  | 25 |  | 7 |  | 15 |  | 13 |  | 9 |  | 12 |  | 12
| $55 |  | $93 |  | $76 |  | $24 |  | $50 |  | $42 |  | $31 |  | $43 |  | $34

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