XML 47 R13.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Investments | 12 Months Ended
--- | ---
Dec. 31, 2023
Schedule of Equity Method Investments [Line Items] |
Investments | INVESTMENTS Unconsolidated Equity Investments - Alliant Energy’s unconsolidated investments accounted for under the equity method of accounting are as follows (in millions):
| Ownership Interest at |  | Carrying Value at December 31, |  | Equity (Income) / Loss
| December 31, 2023 |  | 2023 |  | 2022 |  | 2023 |  | 2022 |  | 2021
ATC Holdings | 16%, 20% |  | $386 |  | $358 |  | ($49) |  | ($41) |  | ($43)
Non-utility wind farm in Oklahoma | 50% |  | 104 |  | 101 |  | (7) |  | (5) |  | (4)
Corporate venture investments | Various |  | 74 |  | 62 |  | (2) |  | (3) |  | (13)
Other | Various |  | 21 |  | 21 |  | (3) |  | (2) |  | (2)
|  |  | $585 |  | $542 |  | ($61) |  | ($51) |  | ($62)
Summary aggregate financial information from the financial statements of these holdings is as follows (in millions):
| Alliant Energy |  |
| 2023 |  | 2022 |  | 2021 |  |  |  |  |  |
Revenues | $898 |  | $813 |  | $802 |  |  |  |  |  |
Operating income | 384 |  | 350 |  | 357 |  |  |  |  |  |
Net income | 370 |  | 675 |  | 358 |  |  |  |  |  |
As of December 31: |  |  |  |  |  |  |  |  |  |  |
Current assets | 221 |  | 227 |  |  |  |  |  |  |  |
Non-current assets | 9,032 |  | 8,292 |  |  |  |  |  |  |  |
Current liabilities | 528 |  | 620 |  |  |  |  |  |  |  |
Non-current liabilities | 3,584 |  | 3,285 |  |  |  |  |  |  |  |
Noncontrolling interest | 259 |  | 289 |  |  |  |  |  |  |  |
ATC Holdings - As of December 31, 2023, Alliant Energy has a 16% ownership interest in ATC and a 20% ownership interest in ATC Holdco LLC, collectively referred to as ATC Holdings. ATC is an independent, for-profit, transmission-only company. ATC Holdco LLC holds Duke-American Transmission Company, LLC, a joint venture between Duke Energy Corporation and ATC, that owns electric transmission infrastructure in North America. Refer to Note 17(g) for discussion of a reduction in earnings recorded in 2022 related to a court decision, which is currently expected to reduce the base return on equity authorized for MISO transmission owners, including ATC. Non-utility Wind Farm in Oklahoma - The non-utility wind farm located in Oklahoma provides electricity to a third-party under a long-term PPA, and has both cash and tax equity ownership. Alliant Energy does not maintain or operate the wind farm, and provided a parent guarantee of its subsidiary’s indemnification obligations under the operating agreement and PPA. Refer to Note 17(d) for discussion of the guarantee. Corporate Venture Investments - Alliant Energy has various minority ownership interests in regional and national venture funds, including a global coalition of energy companies working together to help advance the transition towards a cleaner, more sustainable, and inclusive energy future, by identifying and researching innovative technologies and business models within the emerging energy economy.

X
- Definition The entire disclosure for investment. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -Name Accounting Standards Codification -Publisher FASB -URI https://asc.fasb.org//320/tableOfContent Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Name Accounting Standards Codification -Topic 321 -Publisher FASB -URI https://asc.fasb.org//321/tableOfContent Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Name Accounting Standards Codification -Topic 325 -Publisher FASB -URI https://asc.fasb.org//325/tableOfContent + Details
Name: | us-gaap_InvestmentTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(g)(1)(ii)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 323 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481687/323-10-50-3 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 28 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482907/825-10-50-28 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 323 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481687/323-10-50-3 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 323 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481687/323-10-50-3 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 323 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481687/323-10-50-3 + Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration