10-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K

☒    ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2021

or

☐    TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from                    to                    

Name of Registrant, State of Incorporation, Address of Principal Executive Offices, Telephone Number, Commission File Number, IRS Employer Identification Number

ALLIANT ENERGY CORPORATION

(a Wisconsin Corporation)

4902 N. Biltmore Lane

Madison, Wisconsin 53718

Telephone (608) 458-3311

Commission File Number - 1-9894

IRS Employer Identification Number - 39-1380265

INTERSTATE POWER & LIGHT COMPANY

(an Iowa corporation)

Alliant Energy Tower

Cedar Rapids, Iowa 52401

Telephone (319) 786-4411

Commission File Number - 1-4117

IRS Employer Identification Number - 42-0331370

WISCONSIN POWER & LIGHT COMPANY

(a Wisconsin corporation)

4902 N. Biltmore Lane

Madison, Wisconsin 53718

Telephone (608) 458-3311

Commission File Number - 0-337

IRS Employer Identification Number - 39-0714890

This combined Form 10-K is separately filed by Alliant Energy Corporation, Interstate Power and Light Company and Wisconsin Power and Light Company. Information contained in the Form 10-K relating to Interstate Power and Light Company and Wisconsin Power and Light Company is filed by each such registrant on its own behalf. Each of Interstate Power and Light Company and Wisconsin Power and Light Company makes no representation as to information relating to registrants other than itself.

Securities registered pursuant to Section 12(b) of the Act:

Alliant Energy Corporation, Common Stock, $0.01 Par Value, Trading Symbol LNT, Nasdaq Global Select Market

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.

Alliant Energy Corporation - Yes ☒ No ☐

Interstate Power and Light Company - Yes ☒ No ☐

Wisconsin Power and Light Company - Yes ☒ No ☐

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.

Alliant Energy Corporation - Yes ☐ No ☒

Interstate Power and Light Company - Yes ☐ No ☒

Wisconsin Power and Light Company - Yes ☐ No ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrants were required to file such reports) and (2) has been subject to such filing requirements for the past 90 days.

Alliant Energy Corporation - Yes ☒ No ☐

Interstate Power and Light Company - Yes ☒ No ☐

Wisconsin Power and Light Company - Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).

Alliant Energy Corporation - Yes ☒ No ☐

Interstate Power and Light Company - Yes ☒ No ☐

Wisconsin Power and Light Company - Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, accelerated filer, non-accelerated filer, smaller reporting company, or emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Alliant Energy Corporation - Large Accelerated Filer ☒ Accelerated Filer ☐ Non-accelerated Filer ☐ Smaller Reporting Company ☐ Emerging Growth Company ☐

Interstate Power and Light Company - Large Accelerated Filer ☐ Accelerated Filer ☐ Non-accelerated Filer ☒ Smaller Reporting Company ☐ Emerging Growth Company ☐

Wisconsin Power and Light Company - Large Accelerated Filer ☐ Accelerated Filer ☐ Non-accelerated Filer ☒ Smaller Reporting Company ☐ Emerging Growth Company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

Alliant Energy Corporation ☐

Interstate Power and Light Company ☐

Wisconsin Power and Light Company ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (§ 15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.

Alliant Energy Corporation ☒

Interstate Power and Light Company ☐

Wisconsin Power and Light Company ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).

Alliant Energy Corporation - Yes ☐ No ☒

Interstate Power and Light Company - Yes ☐ No ☒

Wisconsin Power and Light Company - Yes ☐ No ☒

The aggregate market value of the voting and non-voting common equity held by nonaffiliates as of June 30, 2021:

Alliant Energy Corporation - $13.9 billion

Interstate Power and Light Company - $0

Wisconsin Power and Light Company - $0

Number of shares outstanding of each class of common stock as of January 31, 2022:

Alliant Energy Corporation, Common Stock, $0.01 par value, 250,478,681 shares outstanding

Interstate Power and Light Company, Common Stock, $2.50 par value, 13,370,788 shares outstanding (all outstanding shares are owned beneficially and of record by Alliant Energy Corporation)

Wisconsin Power and Light Company, Common Stock, $5 par value, 13,236,601 shares outstanding (all outstanding shares are owned beneficially and of record by Alliant Energy Corporation)

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Proxy Statement relating to Alliant Energy Corporation’s 2022 Annual Meeting of Shareowners are, or will be upon filing with the Securities and Exchange Commission, incorporated by reference into Part III hereof.

TABLE OF CONTENTS

				Page Number
Definitions				1
Forward-looking Statements				1
Website Access to Reports				3
Part I.	Item 1. Business			3
	Item 1A. Risk Factors			15
	Item 1B. Unresolved Staff Comments			21
	Item 2. Properties			21
	Item 3. Legal Proceedings			23
	Item 4. Mine Safety Disclosures			23
	Information About Executive Officers			23
Part II.	Item 5. Market for Registrants’ Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities			24
	Item 6. [Reserved]			24
	Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations			24
	Item 7A. Quantitative and Qualitative Disclosures About Market Risk			40
	Item 8. Financial Statements and Supplementary Data			40
		Alliant Energy Corporation		41
		Interstate Power and Light Company		47
		Wisconsin Power and Light Company		53
		Combined Notes to Consolidated Financial Statements		59
			1. Summary of Significant Accounting Policies	59
			2. Regulatory Matters	65
			3. Property, Plant and Equipment	68
			4. Jointly-owned Electric Utility Plant	69
			5. Receivables	69
			6. Investments	70
			7. Common Equity	71
			8. Preferred Stock	71
			9. Debt	71
			10. Leases	73
			11. Revenues	74
			12. Income Taxes	75
			13. Benefit Plans	77
			14. Asset Retirement Obligations	86
			15. Derivative Instruments	86
			16. Fair Value Measurements	87
			17. Commitments and Contingencies	90
			18. Segments of Business	92
			19. Related Parties	94
	Item 9. Changes in and Disagreements With Accountants on Accounting and Financial Disclosure			94
	Item 9A. Controls and Procedures			95
	Item 9B. Other Information			97
	Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections			97
Part III.	Item 10. Directors, Executive Officers and Corporate Governance			97
	Item 11. Executive Compensation			97
	Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters			97
	Item 13. Certain Relationships and Related Transactions, and Director Independence			98
	Item 14. Principal Accounting Fees and Services			98
Part IV.	Item 15. Exhibits, Financial Statement Schedules			99
	Item 16. Form 10-K Summary			103
Signatures				104

DEFINITIONS

The following abbreviations or acronyms used in this report are defined below:

Abbreviation or Acronym	Definition	Abbreviation or Acronym	Definition
2022 Alliant Energy Proxy Statement	Alliant Energy’s Proxy Statement for the 2022 Annual Meeting of Shareowners	Fuel-related	Electric production fuel and purchased power
AEF	Alliant Energy Finance, LLC	GAAP	U.S. generally accepted accounting principles
AFUDC	Allowance for funds used during construction	GHG	Greenhouse gases
Alliant Energy	Alliant Energy Corporation	IPL	Interstate Power and Light Company
ARO	Asset retirement obligation	IRS	Internal Revenue Service
ATC	American Transmission Company LLC	ITC	ITC Midwest LLC
ATC Holdings	Interest in American Transmission Company LLC and ATC Holdco LLC	IUB	Iowa Utilities Board
ATI	AE Transco Investments, LLC	KWh	Kilowatt-hour
CA	Certificate of authority	Marshalltown	Marshalltown Generating Station
CAA	Clean Air Act	MDA	Management’s Discussion and Analysis of Financial Condition and Results of Operations
CCR	Coal combustion residuals	MGP	Manufactured gas plant
CO2	Carbon dioxide	MISO	Midcontinent Independent System Operator, Inc.
Corporate Services	Alliant Energy Corporate Services, Inc.	MW	Megawatt
COVID-19	Novel coronavirus	MWh	Megawatt-hour
CPCN	Certificate of Public Convenience and Necessity	N/A	Not applicable
CWIP	Construction work in progress	Note(s)	Combined Notes to Consolidated Financial Statements
DAEC	Duane Arnold Energy Center	OIP	Alliant Energy Omnibus Incentive Plan
DCP	Alliant Energy Deferred Compensation Plan	OPEB	Other postretirement benefits
DLIP	Alliant Energy Director Long Term Incentive Plan	PPA	Purchased power agreement
Dth	Dekatherm	PSCW	Public Service Commission of Wisconsin
EEP	Energy efficiency plan	Receivables Agreement	Receivables Purchase and Sale Agreement
EGU	Electric generating unit	Riverside	Riverside Energy Center
EPA	U.S. Environmental Protection Agency	SEC	Securities and Exchange Commission
EPS	Earnings per weighted average common share	U.S.	United States of America
Federal Tax Reform	Tax Cuts and Jobs Act	VEBA	Voluntary Employees’ Beneficiary Association
FERC	Federal Energy Regulatory Commission	VIE	Variable interest entity
Financial Statements	Consolidated Financial Statements	Whiting Petroleum	Whiting Petroleum Corporation
FTR	Financial transmission right	WPL	Wisconsin Power and Light Company

FORWARD-LOOKING STATEMENTS

Statements contained in this report that are not of historical fact are forward-looking statements intended to qualify for the safe harbors from liability established by the Private Securities Litigation Reform Act of 1995. These forward-looking statements can be identified as such because the statements include words such as “may,” “believe,” “expect,” “anticipate,” “plan,” “project,” “will,” “projections,” “estimate,” or other words of similar import. Similarly, statements that describe future financial performance or plans or strategies are forward-looking statements. Such forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from those expressed in, or implied by, such statements. Some, but not all, of the risks and uncertainties of Alliant Energy, IPL and WPL that could materially affect actual results include:

•the impact of penalties or third-party claims related to, or in connection with, a failure to maintain the security of personally identifiable information, including associated costs to notify affected persons and to mitigate their information security concerns;

•the direct or indirect effects resulting from terrorist incidents, including physical attacks and cyber attacks, or responses to such incidents;

•the impact of customer- and third party-owned generation, including alternative electric suppliers, in IPL’s and WPL’s service territories on system reliability, operating expenses and customers’ demand for electricity;

•the impact of energy efficiency, franchise retention and customer disconnects on sales volumes and margins;

•the impact that price changes may have on IPL’s and WPL’s customers’ demand for electric, gas and steam services and their ability to pay their bills;

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•IPL’s and WPL’s ability to obtain adequate and timely rate relief to allow for, among other things, the recovery of and/or the return on costs, including fuel costs, operating costs, transmission costs, deferred expenditures, deferred tax assets, tax expense, capital expenditures, and remaining costs related to EGUs that may be permanently closed and certain other retired assets, decreases in sales volumes, earning their authorized rates of return, and the payments to their parent of expected levels of dividends;

•federal and state regulatory or governmental actions, including the impact of legislation, and regulatory agency orders;

•the ability to utilize tax credits and net operating losses generated to date, and those that may be generated in the future, before they expire;

•the impacts of changes in the tax code, including tax rates, minimum tax rates, and adjustments made to deferred tax assets and liabilities;

•the ability to complete construction of renewable generation and storage projects within the cost targets set by regulators due to cost increases of materials, equipment and commodities including due to tariffs, labor issues or supply shortages, the ability to successfully resolve warranty issues or contract disputes, the ability to achieve the expected level of tax benefits based on tax guidelines and project costs, and the ability to efficiently utilize the renewable generation and storage project tax benefits for the benefit of customers;

•employee workforce factors, including changes in key executives, ability to hire and retain employees with specialized skills, ability to create desired corporate culture, collective bargaining agreements and negotiations, work stoppages or restructurings;

•any material post-closing payments related to any past asset divestitures, including the sale of Whiting Petroleum, which could result from, among other things, indemnification agreements, warranties, guarantees or litigation;

•weather effects on results of utility operations;

•the direct or indirect effects resulting from the ongoing COVID-19 pandemic and the spread of variant strains, including any vaccine mandates and testing requirements, on sales volumes, margins, operations, employees, labor markets, contractors, vendors, the ability to complete construction projects, supply chains, customers’ inability to pay bills, suspension of disconnects, the market value of the assets that fund pension plans and the potential for additional funding requirements, the ability of counterparties to meet their obligations, compliance with regulatory requirements, the ability to implement regulatory plans, economic conditions and access to capital markets;

•issues associated with environmental remediation and environmental compliance, including compliance with all environmental and emissions permits, the CCR rule, future changes in environmental laws and regulations, including federal, state or local regulations for CO2 emissions reductions from new and existing fossil-fueled EGUs, and litigation associated with environmental requirements;

•increased pressure from customers, investors and other stakeholders to more rapidly reduce CO2 emissions;

•the ability to defend against environmental claims brought by state and federal agencies, such as the EPA, state natural resources agencies or third parties, such as the Sierra Club, and the impact on operating expenses of defending and resolving such claims;

•continued access to the capital markets on competitive terms and rates, and the actions of credit rating agencies;

•inflation and interest rates;

•disruptions to the supply of materials, equipment and commodities needed to construct solar generation and storage projects, including due to shortages, labor issues or transportation issues, which may impact the ability to meet capacity requirements and result in increased capacity expense;

•possible changes to MISO’s methodology establishing capacity planning reserve margin and capacity accreditation requirements that may impact how and when new generating facilities such as IPL’s and WPL’s additional solar generation may be accredited with energy capacity and may require IPL and WPL to adjust their current resource plans, the need to add resources to comply with MISO’s proposal, or procure capacity in the market whereby such costs might not be recovered in rates;

•changes in the price of delivered natural gas, transmission, purchased electricity and coal due to shifts in supply and demand caused by market conditions and regulations;

•disruptions in the supply and delivery of natural gas, purchased electricity and coal;

•the direct or indirect effects resulting from breakdown or failure of equipment in the operation of electric and gas distribution systems, such as mechanical problems and explosions or fires, and compliance with electric and gas transmission and distribution safety regulations, including regulations promulgated by the Pipeline and Hazardous Materials Safety Administration;

•issues related to the availability and operations of EGUs, including start-up risks, breakdown or failure of equipment, availability of warranty coverage for equipment breakdowns or failures; performance below expected or contracted levels of output or efficiency, operator error, employee safety, transmission constraints, compliance with mandatory reliability standards and risks related to recovery of resulting incremental costs through rates;

•impacts that excessive heat, excessive cold, storms or natural disasters may have on Alliant Energy’s, IPL’s and WPL’s operations and recovery of costs associated with restoration activities or on the operations of Alliant Energy’s investments;

•Alliant Energy’s ability to sustain its dividend payout ratio goal;

•changes to costs of providing benefits and related funding requirements of pension and OPEB plans due to the market value of the assets that fund the plans, economic conditions, financial market performance, interest rates, timing and form of benefits payments, life expectancies and demographics;

•material changes in employee-related benefit and compensation costs;

•risks associated with operation and ownership of non-utility holdings;

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•changes in technology that alter the channels through which customers buy or utilize Alliant Energy’s, IPL’s or WPL’s products and services;

•impacts on equity income from unconsolidated investments from valuations and potential changes to ATC’s authorized return on equity;

•impacts of IPL’s future tax benefits from Iowa rate-making practices, including deductions for repairs expenditures, allocation of mixed service costs and state depreciation, and recoverability of the associated regulatory assets from customers, when the differences reverse in future periods;

•changes to the creditworthiness of counterparties with which Alliant Energy, IPL and WPL have contractual arrangements, including participants in the energy markets and fuel suppliers and transporters;

•current or future litigation, regulatory investigations, proceedings or inquiries;

•reputational damage from negative publicity, protests, fines, penalties and other negative consequences resulting in regulatory and/or legal actions;

•the effect of accounting standards issued periodically by standard-setting bodies;

•the ability to successfully complete tax audits and changes in tax accounting methods with no material impact on earnings and cash flows; and

•other factors listed in MDA and Item 1A Risk Factors.

Alliant Energy, IPL and WPL each assume no obligation, and disclaim any duty, to update the forward-looking statements in this report, except as required by law.

WEBSITE ACCESS TO REPORTS

Alliant Energy, IPL and WPL make their periodic and current reports, and amendments to those reports, available, free of charge, on Alliant Energy’s website at www.alliantenergy.com/investors on the same day as such material is electronically filed with, or furnished to, the SEC. Alliant Energy, IPL and WPL are not including the information contained on Alliant Energy’s website as a part of, or incorporating it by reference into, this report.

PART I

This report includes information relating to Alliant Energy, IPL and WPL (as well as AEF and Corporate Services). Where appropriate, information relating to a specific entity has been segregated and labeled as such. Unless otherwise noted, the information herein excludes discontinued operations for all periods presented. The terms “we,” “our” and “us” used in this report refer collectively to Alliant Energy, IPL and WPL.

ITEM 1. BUSINESS

A. GENERAL

Alliant Energy maintains its principal executive offices in Madison, Wisconsin. Alliant Energy operates as a regulated investor-owned public utility holding company, and its purpose-driven strategy is to serve its customers and build strong communities. Alliant Energy’s primary focus is to provide regulated electric and natural gas service to approximately 985,000 electric and approximately 425,000 natural gas customers in the Midwest through its two public utility subsidiaries, IPL and WPL. The primary first tier wholly-owned subsidiaries of Alliant Energy are as follows:

1) IPL - is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Iowa. IPL provides utility services to incorporated communities as directed by the IUB and utilizes non-exclusive franchises, which cover the use of public right-of-ways for utility facilities in incorporated communities for a maximum term of 25 years. At December 31, 2021, IPL supplied electric and natural gas service to approximately 500,000 and 225,000 retail customers, respectively, in Iowa. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa. IPL is also engaged in the generation and distribution of steam for two customers in Cedar Rapids, Iowa.

2) WPL - is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Wisconsin. WPL operates in municipalities pursuant to permits of indefinite duration and state statutes authorizing utility operation in areas annexed by a municipality. At December 31, 2021, WPL supplied electric and natural gas service to approximately 485,000 and 200,000 retail customers, respectively. WPL also sells electricity to wholesale customers in Wisconsin.

3) CORPORATE SERVICES - provides administrative services to Alliant Energy, IPL, WPL and AEF.

4) AEF - Alliant Energy’s non-utility holdings are organized under AEF, which manages a portfolio of wholly-owned subsidiaries and additional holdings, including the following distinct platforms:

ATI - currently holds all of Alliant Energy’s interest in ATC Holdings. ATC Holdings is comprised of a 16% ownership interest in ATC and a 20% ownership interest in ATC Holdco LLC. 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.

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Corporate Venture Investments - includes various minority ownership interests in regional and national venture funds, including a coalition with different energy companies across the U.S., working together to help identify and research innovative products, technologies and business models within the emerging energy economy.

Non-utility Wind Farm - includes a 50% cash equity ownership interest in a 225 MW non-utility wind farm located in Oklahoma.

Sheboygan Falls Energy Facility - is a 347 MW, simple-cycle, natural gas-fired EGU near Sheboygan Falls, Wisconsin, which is leased to WPL for an initial period of 20 years ending in 2025.

Travero - is a diversified supply chain solutions company, including a short-line rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; freight brokerage services; and a rail-served warehouse in Iowa, which began operations in 2021.

B. INFORMATION RELATING TO ALLIANT ENERGY ON A CONSOLIDATED BASIS

1) HUMAN CAPITAL MANAGEMENT - Alliant Energy’s core purpose is to serve customers and build strong communities. We constantly strive to attract, retain and develop a diverse and qualified workforce of high-performing employees, and create and foster an environment of inclusion and belonging for all employees.

Employees - At December 31, 2021, Alliant Energy, IPL and WPL had the following full- and part-time employees:

	Total	Number of	Percentage of Employees
	Number of	Bargaining Unit	Covered by Collective
	Employees	Employees	Bargaining Agreements
Alliant Energy	3,313	1,788	54%
IPL	1,185	822	69%
WPL	1,033	854	83%

The majority of IPL’s bargaining unit employees are covered by the International Brotherhood of Electrical Workers Local 204 (Cedar Rapids) collective bargaining agreement, which expires on August 31, 2024. All of WPL’s bargaining unit employees are covered by the International Brotherhood of Electrical Workers Local 965 collective bargaining agreement, which expires on May 31, 2022.

Safety - Safety is integral to our company’s culture. It is one of our Values – “Live safety. Everyone. Always. Our first priority is that nobody gets hurt.” Alliant Energy is committed to providing a safe environment for our employees, visitors, customers, contractors, vendors and the communities in which we live and work.

We focus on the proactive management of our safety performance. Our comprehensive behavioral safety-based program consists of leading indicators, lagging indicators and targeted focus programs. We utilize a formal safety management system to capture and track best practices, near misses, job site briefings, safety observations, safety conversations and any unsafe conditions. This system provides the insights needed to help drive a positive safety culture and help ensure compliance with safety rules, processes and procedures. We also use this system to broadly share lessons learned in support of shaping the mindsets and behaviors needed to help prevent similar events from occurring elsewhere. Collectively, this information is used to evaluate the safety performance of the executive and management teams related to their goals, and safety metrics are factored into short-term incentive awards.

We maintain executive and local safety leadership teams to establish our safety vision, strategy and priorities, and ensure education and recognition of employee actions that improve our safety culture. This leadership provides strong support for sustained growth of both employee and public safety programs and initiatives.

Public safety is equally important as we interact with our customers to provide energy to their homes and businesses. We offer awareness campaigns, natural gas and electric public safety presentations, and free online resources and training programs and guidance to assist local emergency responders.

Refer to “Overview – COVID-19” in MDA for discussion of certain employee safety protocols related to COVID-19.

Total Rewards - Our market-competitive Total Rewards programs are designed to meet the varied and evolving needs of our employees. Through a variety of health, welfare and compensation programs, we offer employees choice and control, while supporting their financial, physical, and mental well-being. Tools and resources are provided to employees to help maintain and improve their health. Short- and long-term incentive plans are designed with a mix of operational and financial metrics that align employees with strategic corporate and social goals.

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In addition to competitive salaries and wages, our Total Rewards programs include:

•competitive short- and long-term incentive compensation;

•a 401(k) savings plan with an employer match;

•healthcare and insurance benefits, including medical, vision, dental, life, short-term disability, and long-term disability insurance;

•health savings and flexible spending accounts;

•paid time off to use for vacation, personal time, sick time, holidays, bereavement, jury duty, military leave, parental leave, maternity leave, and adoption leave;

•adoption assistance;

•legal planning assistance;

•Employee Assistance program;

•tuition reimbursement;

•Vacation Donation program; and

•Volunteer Grants & Matching Gifts program.

Diversity, Equity and Inclusion (DE&I) - A diverse, equitable and inclusive workplace is crucial for the success and retention of our employees, to attract future talent and to execute our purpose-driven strategy to serve our customers and build strong communities. It is one of our Values – “Care for others: Together we create a workplace where people feel like they belong and can use their unique backgrounds, talents and perspectives to their fullest potential.” Alliant Energy is driven by DE&I and believes the achievement of its strategic objectives can only be achieved with a focused and engaged workforce. Alliant Energy’s corporate officers group currently has approximately 40% gender diversity and 27% ethnic diversity.

Our efforts to create a diverse and inclusive workforce include:

•learning opportunities for employees, such as inviting employees to participate in area diversity summits and supporting company-wide listening sessions, speakers and programs;

•Employee Resource Groups that foster a diverse and inclusive workplace that supports employee well-being while promoting professional development and enhancing community relationships; and

•a DE&I Leadership Team that partners with the Human Resources recruiting department and hiring managers to attract more diverse applicants that represent the diversity of the communities we serve.

Our DE&I initiatives also include a focus on building a diverse Board of Directors. We believe it is in our shareowners’ best interest to have a diverse Board representing a wide breadth of experiences and perspectives. Our Board currently has approximately 40% gender diversity and 20% ethnic diversity.

Our 2021 DE&I accomplishments include:

•received a perfect score on the Corporate Equality Index administered by the Human Rights Campaign Foundation to benchmark LGBTQ+ rights, policies and practices;

•selected for the 2021 Bloomberg Gender-Equality Index; and

•held a Day of Understanding where executives met with employees and held conversations around creating a culture of belonging where employees can do the best work of their lives.

Alliant Energy’s short- and long-term incentive compensation plans include diversity metrics to drive leadership accountability for efforts to advance a diverse and inclusive culture.

Talent Development and Workforce Readiness - We support employees in the growth of their careers through several training opportunities and development programs. These include tuition reimbursement, online, instructor-led and on-the-job learning formats, as well as leadership development and succession planning.

In addition, we have an apprenticeship program that combines supervised, structured on-the-job training with related instruction to produce highly skilled trade and technical workers. Our program builds lifetime skills and comprehensive knowledge in the high-demand technical trades necessary for our success. The program gives us the flexibility to tailor training to match our needs – training employees in our facilities, on our equipment, and consistent with our safety standards and employee expectations. We instill company Values, methods and procedures from day one.

2) REGULATION - Alliant Energy, IPL and WPL are subject to regulation by various federal, state and local agencies. The following includes the primary regulations impacting Alliant Energy’s, IPL’s and WPL’s businesses.

FERC -

Public Utility Holding Company Act of 2005 - Alliant Energy is registered with FERC as a public utility holding company, pursuant to the Public Utility Holding Company Act of 2005, and is required to maintain certain records and to report certain transactions involving its public utilities, service company and other entities regulated by FERC. Corporate Services, IPL and WPL are subject to regulation by FERC under the Public Utility Holding Company Act of 2005 for various matters including, but not limited to, affiliate transactions, public utility mergers, acquisitions and dispositions, and books, records and accounting requirements.

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Energy Policy Act of 2005 - The Energy Policy Act of 2005 requires creation of an Electric Reliability Organization to provide oversight by FERC. FERC designated North American Electric Reliability Corporation as the overarching Electric Reliability Organization. Midwest Reliability Organization, which is a regional member of North American Electric Reliability Corporation, has direct responsibility for mandatory electric reliability standards for IPL and WPL.

Federal Power Act of 1935 - FERC also has jurisdiction, under the Federal Power Act of 1935, over certain electric utility facilities and operations, electric wholesale sales, interstate electric transmission rates, dividend payments, issuance of IPL’s securities, and accounting practices of Corporate Services, IPL and WPL.

Electric Wholesale Rates - FERC has authority over IPL's and WPL's wholesale electric market-based rates. Market-based rate authorization allows for wholesale sales of electricity within FERC’s wholesale markets, including the MISO market, and in transactions directly with third parties, based on the market value of the transactions. IPL and WPL also have FERC-approved cost of service formula-based rates related to the provision of firm full- and partial-requirement wholesale electric sales, which allow for true-ups to actual costs, including fuel costs.

Electric Transmission Rates - FERC regulates the rates charged for electric transmission facilities used in interstate commerce. IPL and WPL do not own or operate FERC-regulated electric transmission facilities; however, both IPL and WPL pay for the use of the interstate electric transmission system based upon FERC-regulated rates. IPL and WPL rely primarily on the use of the ITC and ATC transmission systems, respectively.

Natural Gas Act - FERC regulates the transportation and sale for resale of natural gas in interstate commerce under the Natural Gas Act. Under the Natural Gas Act, FERC has authority over certain natural gas facilities and operations of IPL and WPL.

IUB - IPL is subject to regulation by the IUB for various matters including, but not limited to, retail utility rates and standards of service, accounting requirements, sales of assets with values that exceed 3% of IPL’s revenues, and approval of the location and construction of EGUs.

Retail Utility Base Rates - IPL files periodic requests with the IUB for retail rate changes and may base those requests on either historical or forward-looking test periods. The IUB must decide on requests for retail rate changes within 10 months of the date of the application for which changes are filed. The historical test periods may be adjusted for certain known and measurable changes to capital investments, cost of capital and operating and maintenance expenses consistent with IUB rules and regulations. In June 2021, the IUB adopted new rules that establish minimum filing requirements for rate reviews using a forward-looking test period, and a related subsequent proceeding review after the close of the forward-looking test period. The rules provide that in the subsequent proceeding review, a utility’s actual costs and revenues will be presumed to be reasonably consistent with the forward-looking test period if the utility’s actual return on common equity falls within a standard of reasonableness of 50 basis points above to 50 basis points below the authorized return on common equity. If the utility’s actual return on common equity is outside of this range, future rates could be adjusted.

Energy Efficiency - In accordance with Iowa law, IPL is required to file an EEP every five years with the IUB. An EEP provides a utility’s plan and related budget to achieve specified levels of electric and gas energy savings. IUB approval demonstrates that IPL’s EEP is reasonably expected to achieve cost-effective delivery of the energy efficiency programs. Refer to Note 1(g) for discussion of the recovery of these costs from IPL’s retail electric and gas customers.

Electric Generating Units - IPL must obtain a certificate of public convenience, use and necessity (GCU Certificate) from the IUB in order to construct a new, or significantly alter (including fuel switching) an existing, EGU located in Iowa with 25 MW or more of capacity. IPL’s ownership and operation of EGUs (including those located outside the state of Iowa) to serve Iowa customers is subject to retail utility rate regulation by the IUB.

Gas Pipeline Projects - IPL must obtain a pipeline permit from the IUB related to the siting of utility gas pipelines in Iowa that will be operated at a pressure over 150 pounds per square inch and will transport gas to a distribution system or single, large volume customer.

Advance Rate-making Principles - Iowa law provides Iowa utilities with rate-making principles prior to making certain generation investments in Iowa. As a result, IPL may file for, and the IUB must render a decision on, rate-making principles for certain new EGUs located in Iowa, including any alternative energy production facility (such as a wind or solar facility), combined-cycle natural gas-fired EGU, and certain base-load EGUs with a nameplate generating capacity of 300 MW or more (such as nuclear-fired generation). Advance rate-making principles are also available for the repowering of an alternative energy production facility or certain significant alterations of an existing EGU. Upon approval of rate-making principles by the IUB, IPL must either build the EGU or repower the alternative energy production facility under the approved rate-making principles, or not at all.

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Electric Generating Unit Environmental Controls Projects - IPL is required to submit an updated emissions plan and budget biennially to the IUB setting out a multi-year plan and budget for managing regulated emissions from its coal-fired EGUs in a cost-effective manner. IPL must simultaneously submit this plan and budget to the Iowa Department of Natural Resources for a determination of whether the plan and budget meet state environmental requirements for regulated emissions. The reasonable and prudent costs associated with implementing the approved plan are expected to be included in IPL’s future retail electric rates.

PSCW - WPL is subject to regulation by the PSCW related to its operations in Wisconsin for various matters including, but not limited to, retail utility rates and standards of service, accounting requirements, issuance and use of proceeds of securities, affiliate transactions, approval of the location and construction of EGUs and certain other additions and extensions to facilities. In addition, Alliant Energy is subject to regulation by the PSCW for the type and amount of Alliant Energy’s holdings in non-utility businesses and other affiliated interest activities, among other matters.

Retail Utility Base Rates - WPL files periodic requests with the PSCW for retail rate changes. These filings are required to be based on forward-looking test periods. There is no statutory time limit for the PSCW to decide on retail base rate requests. However, the PSCW attempts to process retail base rate reviews in approximately 10 months and has the ability to approve interim retail rate relief, subject to refund, if necessary. Currently, WPL is required to defer a portion of its earnings if its annual regulatory return on common equity exceeds certain levels. Through 2023, any such deferral is required to be offset against the remaining net book value of Edgewater Unit 5, which is currently expected to be retired by early 2023.

Public Benefits - WPL contributes 1.2% of its annual retail utility revenues to help fund Focus on Energy, Wisconsin’s state-wide energy efficiency and renewable energy resource program. In addition, WPL contributes to a program that provides assistance to income-eligible residents in Wisconsin. These contributions are recovered from customers through a monthly bill surcharge of the lesser of 3% of customers’ utilities bills or $750. Refer to Note 1(g) for discussion of the recovery of these costs from WPL’s retail electric and gas customers.

New Electric Generating Units - A CA application is required to be filed with the PSCW for construction approval of any new EGU with a capacity of less than 100 MW and a project cost of $11.9 million or more. WPL must obtain a CPCN from the PSCW in order to construct a new EGU in Wisconsin with a capacity of 100 MW or more. In addition, WPL’s ownership and operation of EGUs (including those located outside the state of Wisconsin) to serve Wisconsin customers are subject to retail utility rate regulation by the PSCW.

Electric Generating Unit Upgrades and Electric Distribution Projects - A CA application is required to be filed with the PSCW for construction approval of any additions to EGUs, including environmental controls projects, as well as electric distribution projects, with estimated project costs of $11.9 million or more.

Gas Distribution Projects - A CA application is required to be filed with the PSCW for construction approval of gas projects with an estimated project cost of $5 million or more and at any time that WPL requests to extend gas service to a new portion of its service territory.

Advance Rate-making Principles - Wisconsin law provides Wisconsin utilities with the opportunity to request rate-making principles prior to the purchase or construction of any EGU utilized to serve Wisconsin customers. WPL is not obligated to file for or accept authorized rate-making principles under Wisconsin law. WPL can proceed with an approved project under traditional rate-making terms or accept authorized rate-making principles under Wisconsin law.

Environmental - Alliant Energy, IPL and WPL are subject to regulation of environmental matters by federal, state and local authorities as a result of their current and past operations. Alliant Energy, IPL and WPL monitor these environmental matters and address them by installing controls that reduce emissions and by implementing operational modifications or other measures to address compliance obligations. There is currently significant regulatory uncertainty with respect to environmental rules and regulations discussed below. Given the evolving nature of environmental regulations and other related regulatory requirements, Alliant Energy, IPL and WPL develop and periodically update their compliance plans to address these environmental obligations. Prudent expenditures incurred by IPL and WPL to comply with environmental requirements are eligible to be recovered in rates from their customers. The following are major environmental matters that could potentially have a significant impact on financial condition and results of operations.

Climate Change and Greenhouse Gas Regulations - In 2007, the Supreme Court provided direction on the EPA’s authority to regulate GHG and ruled that these emissions are covered by the CAA. In 2009, the EPA issued a ruling that found GHG emissions contribute to climate change, and therefore, threaten public health and welfare, which was the prerequisite for implementing CO2 reduction standards under the CAA. While the EPA’s rules to regulate GHG issued under the authority of the CAA remain subject to further review, growing emphasis on climate change and evolving energy technologies are driving efforts to decarbonize the environment through voluntary emissions reductions. The primary GHG directly emitted from Alliant Energy’s utility operations is CO2 from the combustion of fossil fuels at their larger EGUs.

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Clean Air Act Section 111(d) - In 2015, the EPA issued the Clean Power Plan under Section 111(d) of the CAA to reduce CO2 emissions from existing fossil-fueled EGUs through broad electricity system-wide measures. This was replaced by the Affordable Clean Energy rule in 2019, to reduce CO2 emissions from existing coal-fueled EGUs through heat rate improvements. In 2021, the U.S. Court of Appeals for the District of Columbia Circuit vacated and remanded the Affordable Clean Energy rule to the EPA for reconsideration. The EPA is working on a new set of Section 111(d) emission guidelines for states to implement Best System of Emission Reduction standards for GHG emissions from existing fossil-fueled EGUs, and has stated that it intends to issue a proposed rule in 2022 and a final rule in 2023, although such a timeline cannot be predicted with certainty. In addition, the Supreme Court granted review of appeals regarding the extent of the EPA’s authority under Section 111(d) to regulate GHG emissions, with a decision anticipated by June 2022. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these matters.

Clean Air Act Section 111(b) - In 2015, the EPA published final standards under Section 111(b) of the CAA, which establish CO2 emissions limits for certain new fossil-fueled EGUs. Marshalltown and West Riverside are subject to the EPA’s Section 111(b) regulation and have been designed to achieve compliance with these standards. The EPA is reviewing the Section 111(b) standards, and has stated it intends to issue a proposed rule in 2022 and a final rule in 2023, although a timeline cannot be predicted with certainty. Litigation related to Section 111(b) is suspended while the EPA revises its Section 111(b) regulations, and Alliant Energy, IPL and WPL are currently unable to predict with certainty the impact of these standards.

Water Quality -

Effluent Limitation Guidelines - In 2015, the EPA published final effluent limitation guidelines, which required changes to discharge limits for wastewater from certain IPL and WPL steam EGUs. In 2020, revised effluent limitation guidelines (2020 Reconsideration Rule) became effective, which incorporated flexibility to the 2015 rule, including a new subcategory for coal-fired EGUs that will be retired or converted to no longer burn coal before 2028. Compliance for existing steam-electric generating facilities is determined by each facility’s wastewater discharge permit and will generally be required by December 31, 2025. Projects required for compliance are facility-specific. Estimated capital expenditures to comply with the 2020 Reconsideration Rule for 2022 through 2025 are included in the “Other Generation” line in the construction and acquisition expenditures table in “Liquidity and Capital Resources” in MDA. In January 2021, the current Presidential Administration issued an Executive Order requiring the review and possible revision of environmental regulations issued during the prior Administration. As a result, the EPA will undertake a supplemental rule-making to revise the 2020 Reconsideration Rule, and has stated that it intends to issue a proposed rule in 2022. As part of the rule-making process, the EPA is expected to determine whether more stringent limitations and standards are appropriate. The 2020 Reconsideration Rule will remain in effect while the EPA undertakes this new rule-making. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of the anticipated supplemental rule-making.

Land and Solid Waste -

Coal Combustion Residuals Rule - The CCR Rule, which became effective in 2015, regulates CCR as a non-hazardous waste. IPL and WPL have coal-fired EGUs with coal ash ponds and active CCR landfills that are impacted by this rule. Compliance obligations associated with the CCR Rule may be subject to change due to future EPA CCR Rule updates, on-going litigation related to the CCR Rule, and any actions taken to-date that may be challenged. Alliant Energy, IPL and WPL are currently unable to predict with certainty the impact of these updates.

MGP Sites - Refer to Note 17(e) for discussion of IPL’s and WPL’s MGP sites.

Renewable Energy Standards - Iowa and Wisconsin have renewable energy standards, which establish the minimum amount of energy IPL and WPL must supply from renewable resources. IPL primarily relies upon renewable energy generated from the wind resources it owns and renewable energy acquired under PPAs to meet these requirements. WPL utilizes its current renewable portfolio, which primarily consists of wind and hydro energy, both owned and acquired under PPAs, to meet these requirements. IPL and WPL currently exceed their respective renewable energy standards requirements.

3) STRATEGY - Refer to “Overview” in MDA for discussion of Alliant Energy’s strategy, which supports its mission to deliver energy solutions and exceptional service that its customers and communities count on - safely, efficiently, reliably and responsibly.

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C. INFORMATION RELATING TO UTILITY OPERATIONS

Alliant Energy’s utility business (IPL and WPL) has three segments: a) electric operations; b) gas operations; and c) other, which includes IPL’s steam operations and the unallocated portions of the utility business. IPL’s and WPL’s electric, gas and other revenues as a percentage of total revenues were as follows:

IPL WPL

1) ELECTRIC UTILITY OPERATIONS

General - Electric utility operations represent the largest operating segment for Alliant Energy, IPL and WPL. Alliant Energy’s electric utility operations are located in the Midwest with IPL providing retail electric service in Iowa and WPL providing retail and wholesale electric service in Wisconsin. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa. Refer to the “Electric Operating Information” tables for additional details regarding electric utility operations.

Customers - IPL and WPL provide electric utility service to a diversified base of retail customers in several industries, with the largest concentrations in the farming, agriculture, industrial manufacturing, chemical (including ethanol), packaging and food industries. IPL and WPL also sell electricity to wholesale customers, which primarily consist of municipalities and rural electric cooperatives.

Seasonality - Electric sales are seasonal to some extent with the annual peak normally occurring in the summer months due to air conditioning requirements. Electric sales are also impacted to a certain extent in the winter months due to heating requirements.

Competition - Retail electric customers in Iowa and Wisconsin currently do not have the ability to choose their electric supplier, and IPL and WPL have obligations to serve all their retail electric customers. Although electric service in Iowa and Wisconsin is regulated, IPL and WPL still face competition from self-generation by large industrial customers, customer- and third party-owned generation (e.g. solar panels), alternative energy sources, and petitions to municipalize (Iowa) as well as service territory expansions by municipal utilities through annexations (Wisconsin). In addition, the wholesale power market is competitive and IPL and WPL compete against independent power producers, other utilities and MISO market purchases to serve wholesale customers for their electric energy and capacity needs. Alliant Energy’s strategy includes actions to retain current customers and attract new customers into IPL’s and WPL’s service territories in an effort to keep energy rates low for all of their customers. Refer to “Overview” in MDA for discussion of the strategy element focusing on growing customer demand.

Electric Supply - Alliant Energy, IPL and WPL have met, and expect to continue meeting, customer demand of electricity through a mix of electric supply, including owned EGUs, PPAs and additional purchases from wholesale energy markets. Alliant Energy expects its mix of electric supply to change in the next several years with its planned transition away from coal-fired EGUs by incorporating renewable energy such as solar generation, distributed energy resources including community solar and energy storage systems, as well as the actual and potential sale of partial interests in West Riverside to neighboring utilities. Long-term generation plans are intended to meet customer demand, reduce air emissions and water impacts, reduce reliance on wholesale market purchases and mitigate the impacts of future EGU retirements while maintaining compliance with long-term electric demand planning reserve margins, renewable energy standards established by regulators and other various requirements.

Electric Demand Planning Reserve Margin - IPL and WPL are required to maintain a planning reserve margin above their load at the time of the MISO-wide peak to ensure reliability of electric service to their customers. The required installed capacity reserve margin is 17.9% and the required unforced capacity reserve margin is 8.7% for the June 1, 2022 through May 31, 2023 MISO planning year. IPL and WPL utilize accredited capacity from EGUs they own, and have rights to through PPAs, to meet a substantial portion of their current MISO planning reserve margin requirements and periodically rely on short-term market capacity purchases to supplement the accredited capacity from such EGUs.

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Generation Fuel Supply - IPL and WPL own a portfolio of EGUs located in Iowa, Wisconsin and Minnesota with a diversified fuel mix that includes natural gas, renewable resources and coal. Refer to “Properties” in Item 2 for details of IPL’s and WPL’s EGUs. The average cost of delivered fuel per million British Thermal Units used for electric generation was as follows:

	IPL			WPL
	2021	2020	2019	2021	2020	2019
All fuels	$2.10	$2.22	$2.17	$2.62	$2.36	$2.55
Natural gas (a)	2.54	2.54	2.52	3.31	2.51	2.76
Coal	1.81	1.84	1.81	2.07	2.19	2.35

(a)The average cost of natural gas includes commodity and transportation costs, as well as realized gains and losses from swap and option contracts used to hedge the price of natural gas volumes expected to be used by IPL’s and WPL’s natural gas-fired EGUs.

Natural Gas - Alliant Energy, IPL and WPL own several natural gas-fired EGUs, and WPL also has exclusive rights to the output of AEF’s Sheboygan Falls Energy Facility under an affiliated lease agreement. These facilities help meet customer demand for electricity when natural gas prices are low enough to make natural gas-fired generation economical compared to other fuel sources. Alliant Energy manages the gas supply to these gas-fired EGUs and helps ensure an adequate supply is available at known prices through a combination of gas commodity, pipeline transportation and storage agreements held by IPL and WPL for numerous years. Alliant Energy, IPL and WPL believe they are reasonably insulated against gas price volatility for these EGUs given their use of forward contracts and hedging practices, as well as their regulatory cost-recovery mechanisms.

Coal - Coal is one of the fuel sources for owned EGUs. Coal contracts entered into with different entities help ensure that a specified supply of coal is available, and delivered, at known prices for IPL’s and WPL’s coal-fired EGUs. Alliant Energy, IPL and WPL believe their coal supply portfolio represents a reasonable balance between the risks of insufficient supplies and those associated with being unable to respond to future coal market changes. Remaining coal requirements are expected to be met from either future term contracts or purchases in the spot market. Currently, all of the coal utilized by IPL and WPL is from the Wyoming Powder River Basin.

Alliant Energy, IPL and WPL believe they are reasonably insulated against coal price volatility given their current coal procurement process, the specific coal market in their primary purchase region and regulatory cost-recovery mechanisms. The coal procurement process supports periodic purchases, staggering of contract terms, stair-stepped levels of supply going forward and supplier diversity. Similarly, given the term lengths of their transportation agreements and strategic alignment of agreement expirations for negotiation purposes, Alliant Energy, IPL and WPL believe they are reasonably insulated against future higher coal transportation rates from the major railroads.

Purchased Power - IPL and WPL periodically enter into PPAs and purchase electricity from wholesale energy markets to meet a portion of their customer demand for electricity.

Electric Transmission - IPL and WPL do not own electric transmission service assets and currently receive transmission services from ITC and ATC, respectively. ITC and ATC are independent, for-profit, transmission-only companies and are transmission-owning members of the MISO Regional Transmission Organization, Midwest Reliability Organization and Reliability First Corporation Regional Entities. The annual transmission service rates that ITC or ATC charges their customers are calculated each calendar year using a FERC-approved cost of service formula rate. As a result, ITC and ATC can implement new rates each calendar year without filing a request with FERC. However, new rates are subject to challenge by either FERC or customers. If the rates proposed by ITC or ATC are determined by FERC to be unjust or unreasonable, or another mechanism is determined by FERC to be just and reasonable, ITC’s or ATC’s rates would change accordingly. Refer to Note 1(g) for discussion of a transmission cost rider utilized by IPL for recovery of its electric transmission service expense, and discussion of WPL’s electric transmission service expense, which is recovered from its retail electric customers through changes in base rates determined during periodic rate proceedings.

MISO Markets - IPL and WPL are members of MISO, a FERC-approved Regional Transmission Organization, which is responsible for monitoring and ensuring equal access to the transmission system in their footprint. IPL and WPL participate in the wholesale energy and ancillary services markets operated by MISO, which are discussed in more detail below. As agent for IPL and WPL, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases between IPL and WPL based on statements received from MISO.

Wholesale Energy Market - IPL and WPL sell and purchase power in the day-ahead and real-time wholesale energy markets operated by MISO. MISO’s bid/offer-based markets compare the cost of IPL and WPL generation against other generators, which affects IPL and WPL generation operations, energy purchases and energy sales. MISO generally dispatches the lowest cost generators, while recognizing current system constraints, to reduce costs for purchasers in the wholesale energy market. In addition, MISO may dispatch generators that support reliability needs, but that would not have operated based on economic needs. In these cases, MISO’s settlement assures that these generators are made whole financially for their variable costs.

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Ancillary Services Market - IPL and WPL also participate in MISO’s ancillary services market, which integrates the procurement and use of regulation and contingency reserves with the existing wholesale energy market to ensure reliability of electricity supply. MISO’s ancillary services market has had the overall impact of lowering ancillary services costs in the MISO footprint.

Financial Transmission Rights and Auction Revenue Rights - In areas of constrained transmission capacity, energy costs could be higher due to congestion and its impact on locational marginal prices. FTRs provide a hedge for certain congestion costs that occur in the MISO energy market. MISO allocates auction revenue rights to IPL and WPL annually based on a fiscal year from June 1 through May 31 and historical use of the transmission system. The allocated auction revenue rights are used by IPL and WPL to acquire FTRs through the FTR auctions operated by MISO.

Resource Adequacy - MISO has resource adequacy requirements to help ensure adequate resources to meet forecasted peak load obligations plus a reserve margin. Only accredited capacity assigned to EGUs is available to meet these requirements. In order for an EGU to receive accredited capacity, it must meet MISO capacity accreditation requirements, which can include satisfying transmission requirements identified in its interconnection agreement prior to the MISO planning year.

In November 2021, MISO issued proposals to change its methodology for procuring capacity in the energy market effective with the 2023/2024 MISO Planning Year, as a result of changes in the overall generation resource mix due to the shift to renewable generation and the retirement of certain fossil-fueled generation. MISO proposes to change the capacity construct from the current Summer-based annual construct to four distinct seasons to help ensure the continued reliability of the electric transmission grid. MISO’s proposal includes establishing planning reserve margin requirements for all market participants on a seasonal basis and determining a seasonal accredited capacity value for certain classes of generating resources. These changes, if implemented, may require IPL and WPL to adjust their current resource plans, and may result in limited accredited capacity for solar generation during the Winter season and higher accredited capacity for wind generation during the non-Summer seasons. IPL and WPL may need to develop and/or acquire additional resources in order to comply with the new methodology, as well as procure capacity in the market until the new resources are placed in service and accredited by MISO. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these matters.

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Electric Operating Information - Alliant Energy	2021	2020	2019
Revenues (in millions):
Residential	$1,115	$1,093	$1,092
Commercial	763	718	770
Industrial	893	841	889
Retail subtotal	2,771	2,652	2,751
Sales for resale	243	204	250
Other	67	64	63
Total	$3,081	$2,920	$3,064
Sales (000s MWh):
Residential	7,353	7,294	7,207
Commercial	6,383	6,107	6,466
Industrial	11,696	11,134	11,448
Retail subtotal	25,432	24,535	25,121
Sales for resale	5,805	6,046	6,594
Other	71	71	79
Total	31,308	30,652	31,794
Customers (End of Period):
Retail	981,570	974,144	968,485
Other	2,878	2,841	2,816
Total	984,448	976,985	971,301
Other Selected Electric Data:
Maximum summer peak hour demand (MW)	5,486	5,496	5,626
Maximum winter peak hour demand (MW)	4,413	4,158	4,395
Cooling degree days (a):
Cedar Rapids, Iowa (IPL) (normal - 802)	974	800	805
Madison, Wisconsin (WPL) (normal - 687)	845	736	657
Sources of electric energy (000s MWh):
Gas	10,055	10,440	11,060
Purchased power:
Wind (b)	3,529	3,683	2,383
Nuclear	—	2,347	3,748
Other (b)	2,642	2,521	3,264
Wind (b)	5,231	4,872	2,896
Coal	10,218	7,021	8,643
Other (b)	226	254	239
Total	31,901	31,138	32,233
Revenue per KWh sold to retail customers (cents)	10.90	10.81	10.95

(a)Cooling degree days are calculated using a simple average of the high and low temperatures each day compared to a 65 degree base. Normal degree days are calculated using a rolling 20-year average of historical cooling degree days. Refer to “Gas Operating Information” below for details of heating degree days.

(b)All or some of the renewable energy attributes associated with generation from these sources may be used in future years to comply with renewable energy standards or other regulatory requirements.

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Electric Operating Information	IPL			WPL
	2021	2020	2019	2021	2020	2019
Revenues (in millions):
Residential	$620	$602	$601	$495	$491	$491
Commercial	508	474	510	255	244	260
Industrial	505	488	504	388	353	385
Retail subtotal	1,633	1,564	1,615	1,138	1,088	1,136
Sales for resale	74	88	128	169	116	122
Other	45	43	38	22	21	25
Total	$1,752	$1,695	$1,781	$1,329	$1,225	$1,283
Sales (000s MWh):
Residential	3,680	3,623	3,613	3,673	3,671	3,594
Commercial	4,022	3,835	4,109	2,361	2,272	2,357
Industrial	6,581	6,372	6,420	5,115	4,762	5,028
Retail subtotal	14,283	13,830	14,142	11,149	10,705	10,979
Sales for resale	1,807	3,485	4,479	3,998	2,561	2,115
Other	35	34	36	36	37	43
Total	16,125	17,349	18,657	15,183	13,303	13,137
Customers (End of Period):
Retail	496,435	494,258	492,830	485,135	479,886	475,655
Other	858	856	855	2,020	1,985	1,961
Total	497,293	495,114	493,685	487,155	481,871	477,616
Other Selected Electric Data:
Maximum summer peak hour demand (MW)	2,892	2,951	2,944	2,680	2,609	2,682
Maximum winter peak hour demand (MW)	2,433	2,311	2,377	2,028	1,873	2,031
Cooling degree days (a):
Cedar Rapids, Iowa (IPL) (normal - 802)	974	800	805	N/A	N/A	N/A
Madison, Wisconsin (WPL) (normal - 687)	N/A	N/A	N/A	845	736	657
Sources of electric energy (000s MWh):
Gas	4,011	5,296	6,362	6,044	5,144	4,698
Purchased power:
Wind (b)	2,285	2,359	1,788	1,244	1,324	595
Nuclear	—	2,347	3,748	N/A	N/A	N/A
Other (b)	1,166	391	326	1,476	2,130	2,938
Wind (b)	4,088	3,843	2,067	1,143	1,029	829
Coal	4,756	3,185	4,470	5,462	3,836	4,173
Other (b)	12	12	11	214	242	228
Total	16,318	17,433	18,772	15,583	13,705	13,461
Revenue per KWh sold to retail customers (cents)	11.43	11.31	11.42	10.21	10.16	10.35

(a)Cooling degree days are calculated using a simple average of the high and low temperatures each day compared to a 65 degree base. Normal degree days are calculated using a rolling 20-year average of historical cooling degree days. Refer to “Gas Operating Information” below for details of heating degree days.

(b)All or some of the renewable energy attributes associated with generation from these sources may be used in future years to comply with renewable energy standards or other regulatory requirements.

2) GAS UTILITY OPERATIONS

General - Gas utility operations represent the second largest operating segment for Alliant Energy, IPL and WPL. Alliant Energy’s gas utility operations are located in the Midwest with IPL providing gas service in Iowa and WPL providing gas service in Wisconsin. Refer to the “Gas Operating Information” tables for additional details regarding gas utility operations. Refer to Note 1(g) for information relating to utility natural gas cost recovery mechanisms and Note 17(b) for discussion of natural gas commitments.

Customers - IPL and WPL provide gas utility service to a diversified base of retail customers and industries, including research, education, hospitality, manufacturing and chemicals (including ethanol). In addition, IPL and WPL provide transportation service to commercial and industrial customers by moving customer-owned gas through Alliant Energy’s distribution systems to the customers’ meters.

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Seasonality - Gas sales follow a seasonal pattern with an annual base-load of gas and a large heating peak occurring during the winter season. Natural gas obtained from producers, marketers and brokers, as well as gas in storage, is utilized to meet the peak heating season requirements. Storage contracts generally allow IPL and WPL to purchase gas in the summer and inject it into underground storage fields, and remove it from storage fields in the winter to deliver to customers.

Competition - Gas customers in Iowa and Wisconsin currently do not have the ability to choose their gas distributor, and IPL and WPL have obligations to serve all their gas customers. While the gas utility distribution function is expected to remain a regulated function, sales of the natural gas commodity and related services are subject to competition from third-parties who provide alternative fuel sources (e.g. propane). However, when natural gas service is available for a given area, customers in such area have generally selected natural gas over propane as a more cost competitive solution for their fuel needs. Refer to “Customer Investments” in MDA for discussion of plans to expand gas distribution systems.

Gas Supply - IPL and WPL maintain purchase agreements with numerous suppliers of natural gas from various gas producing regions of the U.S. and Canada. In providing gas commodity service to retail customers, Corporate Services administers a diversified portfolio of transportation and storage contracts on behalf of IPL and WPL. The tariffs for IPL’s and WPL’s retail gas customers provide for subsequent adjustments to their rates for the cost of gas sold to these customers. As a result, natural gas prices do not have a material impact on IPL’s or WPL’s gas margins.

Gas Demand Planning Reserve Margin - IPL and WPL are required to maintain adequate pipeline capacity to ensure they meet their customers’ maximum daily system demand requirements. IPL and WPL currently have planning reserve margins of 1% and 7%, respectively, above their forecasted maximum daily system demand requirements from November 2021 through March 2022.

Gas Operating Information - Alliant Energy	2021	2020	2019
Revenues (in millions):
Residential	$257	$214	$259
Commercial	139	107	133
Industrial	17	12	16
Retail subtotal	413	333	408
Transportation/other	43	40	47
Total	$456	$373	$455
Sales (000s Dths):
Residential	26,795	27,809	30,791
Commercial	18,516	17,996	21,611
Industrial	2,868	3,003	3,448
Retail subtotal	48,179	48,808	55,850
Transportation/other	99,179	102,790	97,135
Total	147,358	151,598	152,985
Retail Customers (End of Period)	422,864	419,994	417,322
Other Selected Gas Data:
Heating degree days (a):
Cedar Rapids, Iowa (IPL) (normal - 6,705)	6,539	6,625	7,262
Madison, Wisconsin (WPL) (normal - 6,992)	6,620	6,789	7,397
Revenue per Dth sold to retail customers	$8.57	$6.82	$7.31
Purchased gas costs per Dth sold to retail customers	$5.29	$3.67	$3.89

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Gas Operating Information	IPL			WPL
	2021	2020	2019	2021	2020	2019
Revenues (in millions):
Residential	$146	$116	$149	$111	$98	$110
Commercial	79	59	75	60	48	58
Industrial	12	8	12	5	4	4
Retail subtotal	237	183	236	176	150	172
Transportation/other	28	25	28	15	15	19
Total	$265	$208	$264	$191	$165	$191
Sales (000s Dths):
Residential	13,873	14,521	16,078	12,922	13,288	14,713
Commercial	9,065	8,925	10,906	9,451	9,071	10,705
Industrial	1,943	2,062	2,514	925	941	934
Retail subtotal	24,881	25,508	29,498	23,298	23,300	26,352
Transportation/other	40,738	39,543	38,323	58,441	63,247	58,812
Total	65,619	65,051	67,821	81,739	86,547	85,164
Retail Customers (End of Period)	225,517	224,927	224,613	197,347	195,067	192,709
Other Selected Gas Data:
Maximum daily winter peak demand (Dth)	269,335	253,439	303,508	221,256	189,439	229,022
Heating degree days (a):
Cedar Rapids, Iowa (IPL) (normal - 6,705)	6,539	6,625	7,262	N/A	N/A	N/A
Madison, Wisconsin (WPL) (normal - 6,992)	N/A	N/A	N/A	6,620	6,789	7,397
Revenue per Dth sold to retail customers	$9.53	$7.17	$8.00	$7.55	$6.44	$6.53
Purchased gas cost per Dth sold to retail customers	$5.96	$3.87	$4.06	$4.58	$3.45	$3.70

(a)Heating degree days are calculated using a simple average of the high and low temperatures each day compared to a 65 degree base. Normal degree days are calculated using a rolling 20-year average of historical heating degree days.

3) OTHER UTILITY OPERATIONS - STEAM - IPL’s Prairie Creek facility is the primary source of steam for IPL’s two high-pressure steam customers in Iowa. These customers are each under contract through 2025 for taking minimum quantities of annual steam usage, with certain conditions.

ITEM 1A. RISK FACTORS

You should carefully consider each of the risks described below relating to Alliant Energy, IPL and WPL, together with all of the other information contained in this combined report, before making an investment decision with respect to our securities. If any of the following risks develop into actual events, our business, financial condition or results of operations could be materially and adversely affected, and you may lose all or part of your investment.

Risks Related to Business Operations

A cyber attack may disrupt our operations or lead to a loss or misuse of confidential and proprietary information or potential liability - We operate in an industry that requires the continuous use and operation of sophisticated information technology systems and network infrastructure. We face threats from use of malicious code (such as malware, viruses and ransomware), employee theft or misuse, advanced persistent threats, vulnerabilities such as the log4j vulnerability, fraud attempts, and phishing attacks. More of our workforce is working remotely due to the novel coronavirus (COVID-19) pandemic, which has increased the number of devices connected to the internet that impact our operations and therefore increase our cyber security risk. Incidents of ransomware attacks have been increasing in frequency and magnitude, including the ransomware attack that resulted in the operator of the Colonial Pipeline paying millions of dollars in ransom to hackers as a result of a cyber attack disabling the pipeline for several days in May 2021. Cyber attacks targeting electronic control systems used at our generating facilities and for electric and gas distribution systems could result in a full or partial disruption of our electric and/or gas operations. We have relied on a global supply chain for certain components of our operating and technology systems, which may increase our exposure to cyber attacks. Any disruption of these operations could result in a loss of service to customers and a significant decrease in revenues, as well as significant expense to repair system damage and remedy security breaches. Due to the evolving nature of cyber attacks and cyber security, our current safeguards to protect our operating systems and information technology assets may not always be effective. We rely on third parties for software to protect against cyber attacks and we are at risk if such third parties are targets of cyber attacks. If the technology systems were to fail or be breached by a cyber attack or a computer virus, and not be recovered in a timely fashion, we may be unable to fulfill critical business functions and confidential data could be compromised, adversely impacting our financial condition and results of operation.

In addition, we may collect and retain sensitive information, including personal information about our customers, shareowners and employees. In some cases, we outsource administration of certain functions to vendors that could be targets of cyber attacks. For example, we outsource administration of our employee health insurance to Anthem, which was the target of a

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cyber attack in 2014. Any theft, loss and/or fraudulent use of customer, shareowner, employee or proprietary data as a result of a cyber attack could subject us to significant litigation, liability and costs, as well as adversely impact our reputation with customers and regulators, among others.

Demand for energy may decrease - Our results of operations are affected by the demand for energy in our service territories. Energy demand may decrease due to many things, including proliferation of customer and third party-owned generation, technological advances that reduce the costs of renewable energy and storage solutions for our customers, loss of service territory or franchises, energy efficiency measures, technological advances that improve energy efficiency, third-party disrupters, loss of wholesale customers, the adverse impact of tariffs on our customers, and economic conditions. The loss of sales due to lower demand for energy may increase our rates for remaining customers, as our rates must cover our fixed costs. Increased customer rates may cause decreased demand for energy as customers move to customer and third party-owned generation and implement energy efficiency measures to reduce costs. The loss of customers, the inability to replace those customers with new customers, and the decrease in demand for energy could negatively impact our financial condition and results of operations.

Our strategy includes large construction projects, which are subject to risks - Our strategy includes constructing renewable generating facilities and large-scale additions and upgrades to our electric and gas distribution systems. These construction projects are subject to various risks. These risks include: the inability to obtain necessary regulatory approvals and permits in a timely manner; adverse interpretation or enforcement of permit conditions; changes in applicable laws or regulations; changes in costs of materials, equipment, commodities, fuel or labor including due to tariffs, labor issues, or supply shortages; delays caused by construction accidents or injuries; shortages in materials, equipment, inflation and qualified labor; changes to the scope or timing of the projects; general contractors, subcontractors, or equipment not performing as required under their contracts; the inability to agree to contract terms or disputes in contract terms; the inability to successfully resolve warranty claims; poor initial cost estimates; work stoppages; adverse weather conditions; government actions; legal action; unforeseen engineering or technology issues; limited access to capital or other proposed financing arrangements such as tax equity financing; and other adverse economic conditions. We may not be able to recover all costs for the projects in rates and face increased risk of potential impairment of our project investment if a construction project is not completed or is delayed, or final costs exceed expectations or the costs approved by our regulators. Inability to recover costs, or inability to complete projects in a timely manner, could adversely impact our financial condition and results of operations.

Our utility business is seasonal and may be adversely affected by the impacts of weather - Electric and gas utility businesses are seasonal businesses. Demand for electricity is greater in the summer months associated with higher air conditioning needs and winter months associated with higher heating needs. Demand for natural gas depends significantly upon temperature patterns in winter months due to heavy use in residential and commercial heating. As a result, our overall operating results in the future may fluctuate substantially on a seasonal basis. In addition, we have historically generated less revenues and income when temperatures are warmer in the winter and/or cooler in the summer. Thus, mild winters and/or summers could have an adverse impact on our financial condition and results of operations.

We face risks associated with operating electric and natural gas infrastructure - The operation of electric generation and distribution infrastructure involves many risks, including start-up risks, breakdown or failure of equipment, fires developing from our power lines, transformers or substations, dam failure at one of our hydroelectric facilities, the dependence on a specific fuel source, including the supply and transportation of fuel, the risk of performance below expected or contracted levels of output or efficiency, public and employee safety, operator error and ruptured oil and chemical tanks. The operation of our natural gas transmission and distribution infrastructure also involves many risks, such as leaks, explosions, mechanical problems, members of the public and contractors coming into contact with our infrastructure, and employee and public safety. In addition, the North American electric transmission grid is highly interconnected and, in extraordinary circumstances, disruptions at particular points within the grid could cause an extensive power outage in our service territories. Increased utilization of customer- and third party-owned generation technologies could also disrupt the reliability and balance of the electricity grid. Further, the electric transmission system in our utilities’ service territories can experience constraints, limiting the ability to transmit electricity within our service territories. The transmission constraints could result in an inability to deliver electricity from generating facilities, particularly wind generating facilities, to the national grid, or to access lower cost sources of electricity.

These risks could cause significant harm to employees, customers and the public including loss of human life, significant damage to property, adverse impacts on the environment and impairment of our operations, all of which could result in substantial financial losses to us. We are also responsible for compliance with new and changing regulatory standards involving safety, reliability and environmental compliance, including regulations under the Pipeline and Hazardous Materials Safety Administration, the Occupational Health and Safety Administration, the North American Electric Reliability Corporation and Transportation Security Authority. Failure to meet these regulatory standards could result in substantial fines. Lastly, we have obligations to provide electric and natural gas service to customers under regulatory requirements and contractual commitments. Failure to meet our service obligations could adversely impact our financial condition and results of operations.

Storms or other natural disasters may impact our operations in unpredictable ways - Storms and other natural disasters, including events such as floods, tornadoes, windstorms like the 2020 derecho in Iowa, blizzards, ice storms, extreme hot temperatures, extreme cold temperatures, fires, solar flares or pandemics may adversely impact our ability to generate,

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purchase or distribute electric energy and gas or obtain fuel or other critical supplies. In addition, we could incur large costs to repair damage to our generating facilities and electric and gas infrastructure, or costs related to environmental remediation, due to storms or other natural disasters. The restoration costs may not be fully covered by insurance policies and may not be fully recovered in rates, or recovery in rates may be delayed. Storms and natural disasters may impact our customers and the resulting reduced demand for energy could cause lower sales and revenues, which may not be replaced or recovered in rates, or rate recovery may be delayed. Any of these items could adversely impact our financial condition and results of operations.

The COVID-19 pandemic and the spread of variant strains could adversely affect our business functions, financial condition, results of operations and cash flows - The ongoing COVID-19 pandemic and the spread of variant strains has resulted in widespread impacts on the economy, including disruptions to supply chains, and reduced labor availability and productivity. The COVID-19 pandemic has impacted, and may continue to impact, the economic conditions in our service territories, which may adversely impact our sales and our customers’ abilities to pay their bills. Travel and transportation restrictions and closures of commercial spaces and industrial facilities have been imposed in and across the U.S., including in the service territories in which we operate. Governmental and regulatory responses to COVID-19 have included suspending service disconnects, which may increase customer account arrears, possibly increasing our allowance for expected credit losses and decreasing our cash flows.

Closures of commercial spaces and industrial facilities, stay-at-home trends, work-from-home trends, and business disruptions have impacted sales volumes. These trends may result in a reduction in demand for electricity and natural gas from retail customers. Negative impacts on the economy resulting from the continued pandemic could adversely impact the market value of the assets that fund our pension plans, which could necessitate accelerated funding of the plans to meet minimum federal government requirements. The negative impacts on the economy, labor markets, and supply chains could also adversely impact the ability of counterparties to meet contractual payment obligations, including guarantees, or deliver contracted commodities and other goods or services at the contracted price, which could increase company expenses. Our access to the capital markets could be adversely affected by COVID-19, which could cause us to need alternative sources of funding for our operations and for working capital, any of which could increase our cost of capital.

Travel bans and restrictions, quarantines, and vaccine mandates have caused, and may continue to cause, disruptions in supply chains or access to labor that may adversely impact our planned construction projects, our ability to satisfy compliance requirements, or our operations, including our ability to maintain reliable electric and gas service. This may cause us to miss milestones on construction projects and experience operational delays, which, in the case of renewable energy projects, could delay our completion of such projects past the in-service dates required to qualify for the maximum general renewable tax credits for investments in such renewable energy projects. We have modified certain business practices to be consistent with government restrictions and best practices encouraged by government and regulatory authorities and developed risk mitigation plans for critical items and services required to continue our operations. The effects of these government restrictions could adversely impact implementation of our regulatory plans and our operations. If our workforce contracts COVID-19, it could negatively impact our operations, including our ability to maintain reliable electric and gas service.

The degree to which COVID-19 and the spread of the variant strains may impact our business operations, financial condition and results of operations is unknown at this time and will depend on future developments, including the continued spread of COVID-19 and its variants, the severity of the disease, the duration of the pandemic, possible resurgence of the disease at a later date, emergence of variants, speed, efficacy and adoption rates of vaccines, and further actions that may be taken by governmental and regulatory authorities.

Threats of terrorism and catastrophic events that could result from terrorism may impact our operations in unpredictable ways - We are subject to direct and indirect effects of terrorist threats and activities. Generation, transmission and distribution facilities, in general, have been identified as potential targets of physical or cyber attacks. Physical attacks on transmission and distribution facilities that appeared to be terrorist-style attacks have occurred. Our gas distribution system could also be the target of terrorist threats and activities. The risks posed by such attacks could include, among other things, the inability to generate, purchase or distribute electric energy or obtain fuel sources, the increased cost of security and insurance, the disruption of, volatility in, or other effects on capital markets, and a decline in the economy and/or energy usage within our service territories, all of which could adversely impact our financial condition and results of operations. In addition, the cost of repairing damage to our facilities and infrastructure caused by acts of terrorism, and the loss of revenue if such events prevent us from providing utility service to our customers, could adversely impact our financial condition and results of operations.

We may not be able to fully recover costs related to commodity prices - We have natural gas and coal supply and transportation contracts in place for some of the natural gas and coal we require to generate electricity. We also have transportation and supply agreements in place to facilitate delivery of natural gas to our customers. Our counterparties to these contracts may not fulfill their obligations to provide natural gas or coal to us due to financial or operational problems caused by natural disasters, severe weather, economic conditions, pandemics, physical attacks or cyber attacks. If we were unable to obtain enough natural gas or coal for our electric generating facilities under our existing contracts, or to obtain electricity under existing or future purchased power agreements, we could be required to purchase natural gas or coal at higher prices or forced to purchase electricity from higher-cost generating resources in the Midcontinent Independent System Operator, Inc. (MISO) energy market. We may be obligated to pay for coal deliveries under our contracts even if our coal-fired

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generating facilities do not operate enough to fully utilize the amounts of coal covered by the contracts. If, for natural gas delivery to our customers, we were unable to obtain our natural gas supply requirements under existing or future natural gas supply and transportation contracts, we could be required to purchase natural gas at higher prices from other sources. Natural gas market prices have been volatile in the past and could be volatile in the future due to additional future regulations, increased demand including due to increased liquified natural gas demand from foreign countries, periods of extremely cold temperatures or disruption in supply caused by major storms or pipeline explosions. We may not be able to pass on all of the changes in costs to our customers, especially at WPL where we do not have an automatic retail electric fuel cost adjustment clause to timely recover such costs and where electric fuel cost recovery may be limited if WPL earns in excess of its authorized return on common equity. Increases in prices and costs due to disruptions that are not recovered in rates fully, in a timely manner, may adversely impact our financial condition and results of operations.

Energy industry changes could have a negative effect on our businesses - We operate in a highly regulated business environment. The advent of new and unregulated markets has the potential to significantly impact our financial condition and results of operations. Further, competitors may not be subject to the same operating, regulatory and financial requirements that we are, potentially causing a substantial competitive disadvantage for us. Changes in public policy that could be the result of a new Presidential Administration, such as new tax incentives that we cannot take advantage of or efforts to deregulate the utility industry, could provide an advantage to competitors. Changes in technology could also alter the channels through which electric customers buy or utilize power, which could reduce the revenues or increase the expenses of our utility companies. Increased competition in our primary retail electric service territories may have an adverse impact on our financial condition and results of operations.

We face risks related to non-utility operations - We rely on our non-utility operations for a portion of our earnings. If our non-utility holdings do not perform at expected levels, we could experience an adverse impact on our financial condition and results of operations.

Risks Related to Laws and Regulations

Our utility business is significantly impacted by government legislation, regulation and oversight - Our utility financial condition is influenced by how regulatory authorities, including the IUB, the PSCW and FERC, establish the rates we can charge our customers, our authorized rates of return and common equity levels, and the costs that may be recovered from customers. Our ability to timely obtain rate adjustments to earn authorized rates of return depends upon timely regulatory action under applicable statutes and regulations, and cannot be guaranteed. In future rate reviews, IPL and WPL may not receive an adequate amount of rate relief to recover all costs and earn their authorized rates of return, rates may be reduced, rate refunds may be required, rate adjustments may not be approved on a timely basis, costs may not be otherwise recovered through rates, future rates may be temporarily frozen, certain rate base items may not receive a full weighted average cost of capital, and authorized rates of return on capital may be reduced. As a result, we may experience adverse impacts on our financial condition and results of operations.

In addition, our operations are subject to extensive regulation primarily by the IUB, the PSCW and FERC. We are also subject to oversight and monitoring by organizations such as the North American Electric Reliability Corporation, the Midwest Reliability Organization, the Pipeline and Hazardous Materials Safety Administration, MISO and the Transportation Security Administration. The impacts on our operations include: our ability to site and construct new generating facilities, such as renewable energy projects, and recover associated costs, including our ability to continue to use a renewable energy rider in Iowa; our ability to decommission generating facilities and recover related costs and the remaining carrying value of these facilities and related assets; possible changes to MISO’s methodology establishing capacity planning reserve margin requirements that may impact how and when new generating facilities such as IPL’s and WPL’s additional solar and wind generation may be accredited with energy capacity and may require IPL and WPL to adjust their current resource plans, the need to add additional resources to comply with MISO’s proposal, or procure capacity in the market whereby such costs might not be recovered in rates; the impact of the lack of availability of existing and new generating facilities has on our accredited capacity for such facilities pursuant to MISO’s methodology for establishing capacity planning reserve margin requirements; the rates paid to transmission operators and how those costs are recovered from customers, including our ability to continue to use a transmission rider in Iowa; our ability to site, construct and recover costs for new natural gas pipelines; our ability to recover costs to upgrade our electric and gas distribution systems; the amount of certain sources of energy we must use, such as renewable sources; our ability to purchase generating facilities and recover the costs associated therewith; our ability to sell utility assets and any conditions placed upon the sale of such assets; our ability to enter into purchased power agreements and recover the costs associated therewith; the allocation of expenditures by transmission companies on transmission network upgrades and our ability to recover costs associated therewith; reliability; safety; the issuance of securities and ability to use other financing arrangements, such as tax equity financing to finance renewable energy projects; accounting matters; and transactions between affiliates. These regulatory authorities and organizations are also empowered to impose financial penalties and other sanctions, including requirements to implement new compliance programs. Failure to obtain approvals for any of these matters in a timely manner, or receipt of approvals with uneconomical conditions, may cause us not to pursue the construction of such projects or to record an impairment of our assets and may have a material adverse impact on our financial condition and results of operations. Changes to these regulations could materially increase our costs or cause us to reconsider our strategy, which could have a material adverse impact on our financial condition and results of operations.

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Provisions of the Wisconsin Utility Holding Company Act may limit our ability to invest in or grow our non-utility activities and may deter potential purchasers who might be willing to pay a premium for our stock.

Changes to certain tax elections, tax regulations and future taxable income could negatively impact our financial condition and results of operations - We have significantly reduced our federal and state income tax obligations through tax planning strategies and the utilization of bonus depreciation deductions for certain expenditures for property. These tax planning strategies and bonus depreciation deductions have generated large taxable losses and tax credits that have resulted in significant federal and state net operating losses and tax credit carryforwards. We plan to utilize substantially all of these net operating losses and tax credit carryforwards in the future to reduce our income tax obligations. If we cannot generate enough taxable income in the future to utilize all of the net operating losses and tax credit carryforwards before they expire due to lower than expected financial performance or changes to tax regulations, we may incur material charges to earnings. In addition, our tax liability is determined by our taxable income multiplied by the current tax rates in effect. If the tax rates are increased or a minimum corporate income tax is implemented, as has been proposed by the current Presidential Administration, we may experience adverse impacts to our financial condition and results of operations.

Our utility business currently operates wind generating facilities, which generate production tax credits for us to use to reduce our federal tax obligations. The amount of production tax credits we earn is dependent on the date the qualifying generating facilities are placed in service, the level of electricity output generated by our qualifying generating facilities and the applicable tax credit rate. If there is a disagreement on the in-service date, the amount of production tax credits that we can generate may be significantly reduced. A variety of operating and economic parameters, including transmission constraints, the imbalance of supply and demand of wind energy resulting in unfavorable pricing for wind energy, adverse weather conditions and breakdown or failure of equipment, could significantly reduce the production tax credits generated by our wind farms resulting in a material adverse impact on our financial condition and results of operations. Our strategic plan includes developing solar generating facilities, which are expected to generate investment tax credits. Investment tax credits are dependent on the date the qualifying generating facilities begin and end construction and the costs of the qualifying generating facilities. If there is a disagreement on the dates construction began and ended or the qualifying costs, the amount of investment tax credits awarded may be significantly reduced, possibly adversely impacting our financial condition and results of operations.

Our utility businesses are subject to numerous environmental laws and regulations - Our utilities are subject to numerous federal, regional, state and local environmental laws, regulations, court orders, and international treaties. These laws, regulations and court orders generally concern emissions into the air, discharges into water, use of water, wetlands preservation, remediation of contamination, waste disposal and containment, disposal of coal combustion residuals, hazardous waste disposal, threatened and endangered species, and noise regulation, among others. Failure to comply with such laws, regulations and court orders, or to obtain or comply with any necessary environmental permits pursuant to such laws and regulations, could result in injunctions, fines or other sanctions. Environmental laws and regulations affecting power generation and electric and gas distribution are complex and subject to continued uncertainty and could be changed by the current Presidential Administration. These laws and regulations have imposed, and proposed laws and regulations could impose in the future, additional costs on our utility operations. We have incurred, and will continue to incur, capital and other expenditures to comply with these and other environmental laws and regulations. Changes in or new development of environmental restrictions may force us to incur significant expenses or expenses that may exceed our estimates. There can be no assurance that we would be able to recover all or any increased environmental costs from our customers. Failure to comply with the laws, regulations and court orders, changes in the laws and regulations and failure to recover costs of compliance may adversely impact our financial condition and results of operations.

Actions related to global climate change and reducing greenhouse gas (GHG) emissions could negatively impact us - Regulators, customers and investors continue to raise concerns about climate change and GHG emissions. National regulatory action and international regulatory actions continue to evolve. We are focused on executing a long-term strategy to deliver reliable and affordable energy with lower carbon dioxide (CO2) emissions independent of changing policies and political landscape. However, it is unclear how these climate change concerns will ultimately impact us. We could incur costs or other obligations to comply with future GHG regulations, and could become the target of legal claims or challenges, because generating electricity using fossil fuels emits CO2 and other GHGs. Further, investors may determine that we are too reliant on fossil fuels, reducing demand for our stock, which may cause our stock price to decrease, or not buy our debt securities, which may cause our cost of capital to increase. We could face additional pressures from customers, investors or other stakeholders to more rapidly reduce CO2 emissions on a voluntary-basis, including faster adoption of lower CO2 emitting technologies and management of excess renewable energy credits. The timing and pace to fully achieve decarbonization is also contingent on the future development of technologies to reliably store and manage electricity, as well as electrification of other economic sectors. The EPA’s approach and timing for implementing rules to regulate CO2 emissions at fossil-fuel fired electric generating units remains undecided and subject to litigation and could change in the current Presidential Administration. Various legislative and regulatory proposals to address climate change at the national, state and local levels continue to be introduced. Potential future requirements to reduce CO2, methane and other GHGs from the energy and manufacturing sectors could affect our operations in various ways. Regulation or legislation mandating CO2 emissions reductions or other clean energy standards affecting utility companies could materially increase costs, causing some electric generating units to be uneconomical to operate or maintain. We are vulnerable to potential risks associated with transition to a lower-carbon economy that may extend to our supply chain and natural gas operations. Regulation of oil and gas production

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could affect our upstream supply of natural gas for electricity generation and to provide directly to our residential and business customers from our local distribution company. This could result in rapid increased demand for alternative non-fossil energy sources and economy-wide electrification. Changes to regional and local climate trends such as the frequency, seasonality, and severity of weather conditions could directly and indirectly impact our company. Acute and chronic physical risks could disrupt our operations or affect our property. Furthermore, it could affect the timing of peak demand and overall energy consumption of our customers. We cannot provide any assurance regarding the potential impacts of climate change or related policies and regulations to reduce GHG emissions on our operations and these could have a material adverse impact on our financial condition and results of operations.

Risks Related to Economic, Financial and Labor Market Conditions

We are subject to employee workforce factors that could affect our businesses - We operate in an industry that requires specialized technical skills. Further, we must build a workforce that is innovative, customer-focused and competitive to thrive in the future in order to successfully implement our strategy. It may be difficult to hire and retain such a skilled workforce due to labor market conditions, such as low unemployment rates in our service territories, the length of time employees need to acquire the skills, and general competition for talent. We are also subject to collective bargaining agreements covering approximately 1,800 employees. Any work stoppage experienced in connection with negotiations of collective bargaining agreements could adversely affect our financial condition and results of operations as well as our ability to implement our strategy.

We are subject to limitations on our ability to pay dividends - Alliant Energy is a holding company with no significant operations of its own. The primary sources of funds for Alliant Energy to pay dividends to its shareowners are dividends and distributions from its subsidiaries, primarily its utility subsidiaries. Our subsidiaries are separate and distinct legal entities and have no obligation to pay any amounts to Alliant Energy, whether by dividends, distributions, loans or other payments. The ability of our subsidiaries to pay dividends or make distributions to Alliant Energy and, accordingly, our ability to pay dividends on Alliant Energy common stock will depend on regulatory limitations, earnings, cash flows, capital requirements and general financial condition of our subsidiaries. Our utilities have dividend payment restrictions based on the terms of regulatory limitations applicable to them. If we do not receive adequate dividends and distributions from our subsidiaries, then we may not be able to make, or may have to reduce, dividend payments on Alliant Energy common stock.

We may incur material post-closing adjustments related to past asset and business divestitures - We have sold certain non-utility subsidiaries such as Whiting Petroleum Corporation (Whiting Petroleum). We may continue to incur liabilities relating to our previous ownership of, or the transactions pursuant to which we disposed of, these subsidiaries and assets. Any potential liability depends on a number of factors outside of our control, including the financial condition of Whiting Petroleum, certain of its partners, and/or their assignees. Any required payments on retained liabilities, guarantees or indemnification obligations with respect to Whiting Petroleum or other past and future asset or business divestitures could adversely impact our financial condition and results of operations.

We are dependent on the capital markets and could be negatively impacted by disruptions in the capital markets - Successful implementation of our strategy is dependent upon our ability to access the capital markets. We have forecasted capital expenditures of approximately $7 billion over the next four years. Disruption, uncertainty or volatility in the capital markets could increase our cost of capital or limit our ability to raise funds needed to operate our businesses. Disruptions could be caused by Federal Reserve policies and actions, currency concerns, inflation, economic downturn or uncertainty, monetary policies, a negative view of the utility industry or our company, failures of financial institutions, U.S. debt management concerns, U.S. debt limit and budget debates, including government shutdowns, European and worldwide sovereign debt concerns, other global or geopolitical events, or other factors. Increases in interest rates may cause the price of our equity securities to decline. Any disruptions in capital markets could adversely impact our ability to implement our strategy.

We rely on our strong credit ratings to access the credit markets. If our credit ratings are downgraded for any reason, such as worsening credit metric impacts, negative changes to our regulatory environment, or general negative outlook for the utility industry, we could pay higher interest rates in future financings, the pool of potential lenders could be reduced, borrowing costs under existing credit facilities could increase, our access to the commercial paper market could be limited, or we could be required to provide additional credit assurance, including cash collateral, to contract counterparties. If our access to capital were to become significantly constrained or costs of capital increased significantly due to lowered credit ratings, prevailing industry conditions, regulatory constraints, volatility of the capital markets, inflation or other factors, our financial condition and results of operations could be adversely affected.

Our pension and other postretirement benefits plans are subject to investment and interest rate risk that could negatively impact our financial condition - We have pension and other postretirement benefits plans that provide benefits to many of our employees and retirees. Costs of providing benefits and related funding requirements of these plans are subject to changes in the liabilities of the plans and market value of the assets that fund the plans. The funded status of the plans and the related costs reflected in our financial statements are affected by various factors, which are subject to an inherent degree of uncertainty, including economic conditions, financial market performance, interest rates, life expectancies and demographics. Recessions and volatility in the domestic and international financial markets have negatively affected the asset values of our pension plans at various times in the past. Poor investment returns or lower interest rates may necessitate

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accelerated funding of the plans to meet minimum federal government requirements, which could have an adverse impact on our financial condition and results of operations.

ITEM 1B. UNRESOLVED STAFF COMMENTS

None.

ITEM 2. PROPERTIES

Alliant Energy - As a holding company, Alliant Energy doesn’t directly own any significant properties other than the stock of its subsidiaries. The principal properties of those subsidiaries are as follows:

IPL and WPL

Electric - At December 31, 2021, IPL’s and WPL’s facilities by primary fuel type were as follows:

IPL		Nameplate	Generating
	In-service	Capacity	Capacity
Name of Facility and Location	Dates	in MW	in MW (a)
Marshalltown Generating Station (Units 1-3); Marshalltown, IA	2017	706	625
Emery Generating Station (Units 1-3); Mason City, IA	2004	603	532
Burlington Generating Station (Unit 1); Burlington, IA	1968	212	167
Marshalltown Combustion Turbines (Units 1-3); Marshalltown, IA	1978	189	144
Prairie Creek Generating Station (Unit 4); Cedar Rapids, IA	1967	149	113
Burlington Combustion Turbines (Units 1-4); Burlington, IA	1994-1996	79	35
Total Gas		1,938	1,616
Upland Prairie (121 Units); Clay and Dickinson Cos., IA	2019	299	89
Whispering Willow - North (81 Units); Franklin Co., IA	2020	201	36
Whispering Willow - East (121 Units); Franklin Co., IA	2009	200	28
Golden Plains (82 Units); Winnebago and Kossuth Cos., IA	2020	200	33
English Farms (69 Units); Poweshiek Co., IA	2019	172	27
Richland (53 Units); Sac Co., IA	2020	131	21
Franklin County (60 Units); Franklin Co., IA	2012	99	14
Total Wind		1,302	248
Ottumwa Generating Station (Unit 1); Ottumwa, IA (b)	1981	348	315
Lansing Generating Station (Unit 4); Lansing, IA	1977	275	206
George Neal Generating Station (Unit 4); Sioux City, IA (c)	1979	179	157
George Neal Generating Station (Unit 3); Sioux City, IA (d)	1975	164	140
Prairie Creek Generating Station (Units 1 and 3); Cedar Rapids, IA	1958-1997	65	29
Louisa Generating Station (Unit 1); Louisa, IA (e)	1983	32	28
Total Coal		1,063	875
Lime Creek Combustion Turbines (Units 1-2); Mason City, IA	1991	90	66
Total Oil		90	66
Dubuque Solar Garden; Dubuque, IA	2017	5	2
Marshalltown Solar Garden; Marshalltown, IA	2020	3	1
Total Solar		8	3
Battery Storage; Decorah, Wellman and Marshalltown, IA	2019-2021	4	—
Total Battery Storage		4	—
Total capacity		4,405	2,808

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WPL		Nameplate	Generating
	In-service	Capacity	Capacity
Name of Facility and Location	Dates	in MW	in MW (a)
Riverside Energy Center (Units 1-3); Beloit, WI	2004	675	503
West Riverside Energy Center (Units 1-3); Beloit, WI (f)	2020	658	595
Neenah Energy Facility (Units 1-2); Neenah, WI	2000	371	294
South Fond du Lac Combustion Turbines (2 Units); Fond du Lac, WI (g)	1994	191	161
Total Gas		1,895	1,553
Bent Tree (122 Units); Freeborn Co., MN	2010-2011	201	26
Kossuth (56 Units); Kossuth Co., IA	2020	152	25
Cedar Ridge (41 Units); Fond du Lac Co., WI	2008	68	8
Forward Wind Energy Center (37 Units); Dodge and Fond du Lac Cos., WI (h)	2008	59	7
Total Wind		480	66
Columbia Energy Center (Units 1-2); Portage, WI (i)	1975-1978	595	585
Edgewater Generating Station (Unit 5); Sheboygan, WI	1985	414	397
Total Coal		1,009	982
Prairie du Sac Hydro Plant (8 Units); Prairie due Sac, WI	1914-1940	33	12
Kilbourn Hydro Plant (4 Units); Wisconsin Dells, WI	1926-1939	10	6
Total Hydro		43	18
West Riverside Solar Garden, Beloit, WI (j)	2021	4	—
Total Solar		4	—
Total capacity		3,431	2,619

(a)Based on the accredited generating capacity of the EGUs as of December 31, 2021 included in MISO’s resource adequacy process for the planning period from June 2021 through May 2022. IPL’s Battery Storage did not receive any accredited generating capacity for the planning period from June 2021 through May 2022. Electricity generated from the West Riverside Solar Garden is used to offset electricity usage at the West Riverside Energy Center and does not receive any accredited generating capacity.

(b)Represents IPL’s 48% ownership interest in this 726 MW (nameplate capacity) / 656 MW (generating capacity) EGU, which is operated by IPL.

(c)Represents IPL’s 25.695% ownership interest in this 696 MW (nameplate capacity) / 610 MW (generating capacity) EGU, which is operated by MidAmerican Energy Company.

(d)Represents IPL’s 28% ownership interest in this 584 MW (nameplate capacity) / 501 MW (generating capacity) EGU, which is operated by MidAmerican Energy Company.

(e)Represents IPL’s 4% ownership interest in this 812 MW (nameplate capacity) / 708 MW (generating capacity) EGU, which is operated by MidAmerican Energy Company.

(f)Represents WPL’s 91% ownership interest in this 723 MW (nameplate capacity) / 654 MW (generating capacity) EGU, which is operated by WPL.

(g)Represents Units 2 and 3, which WPL owns. WPL also operates, but does not own, South Fond du Lac Combustion Turbines Units 1 and 4.

(h)Represents WPL’s 42.64% ownership interest in this 138 MW (nameplate capacity) / 17 MW (generating capacity) EGU, which is operated by Invenergy Services, LLC.

(i)Represents WPL’s 53.5% ownership interest in this 1,112 MW (nameplate capacity) / 1,093 MW (generating capacity) EGU, which is operated by WPL.

(j)Represents WPL’s 91% ownership interest in this 4 MW (nameplate capacity) EGU, which is operated by WPL.

IPL and WPL own overhead electric distribution line, underground electric distribution cable and substation distribution transformers, substantially all of which are located in Iowa for IPL and Wisconsin for WPL.

Gas - IPL’s and WPL’s gas properties consist primarily of mains and services, meters, regulating and gate stations and other related transmission and distribution equipment. IPL’s and WPL’s gas distribution facilities include gas mains located in Iowa and Wisconsin, respectively.

Other - IPL’s other property includes steam service assets. Refer to Note 10 for information regarding WPL’s lease of the Sheboygan Falls Energy Facility from AEF’s Non-utility Generation business.

Corporate Services - Corporate Services’ property included in “Property, plant and equipment, net” on Alliant Energy’s balance sheet at December 31, 2021 consisted primarily of a customer billing and information system for IPL and WPL and other computer software, and the corporate headquarters building located in Madison, Wisconsin.

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AEF - AEF’s principal properties included in “Property, plant and equipment, net” on Alliant Energy’s balance sheet at December 31, 2021 were as follows:

Non-utility Generation - Includes the Sheboygan Falls Energy Facility, a 347 MW, simple-cycle, natural gas-fired facility near Sheboygan Falls, Wisconsin that was placed in service in 2005 and is leased to WPL. The Sheboygan Falls Energy Facility was accredited with 295 MW of generating capacity for MISO’s resource adequacy process for the planning period from June 2021 through May 2022.

Travero - Includes a short-line rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; freight brokerage services; and a rail-served warehouse in Iowa, which began operations in 2021.

ITEM 3. LEGAL PROCEEDINGS

None. SEC regulations require Alliant Energy, IPL and WPL to disclose information about certain proceedings arising under federal, state or local environmental provisions when a governmental authority is a party to the proceedings and such proceedings involve potential monetary sanctions that Alliant Energy, IPL and WPL reasonably believe will exceed a specified threshold. Pursuant to the SEC regulations, Alliant Energy, IPL and WPL use a threshold of $1 million for purposes of determining whether disclosure of any such proceedings is required. Applying this threshold, there are no environmental matters to disclose for this period. Refer to Note 17(c) for discussion of legal and administrative proceedings before various courts and agencies with respect to matters arising in the ordinary course of business.

ITEM 4. MINE SAFETY DISCLOSURES

None.

INFORMATION ABOUT EXECUTIVE OFFICERS

The executive officers of Alliant Energy, IPL and WPL for which information must be included are the same; however, different positions may be held at the various registrants. None of the executive officers for Alliant Energy, IPL or WPL listed below are related to any member of the Board of Directors or nominee for director or any other executive officer. All of the executive officers have no definite terms of office and serve at the pleasure of the Board of Directors. The executive officers of Alliant Energy, IPL and WPL as of the date of this filing are as follows:

Name	Age as of Filing Date	Registrant	Positions
John O. Larsen	58	Alliant Energy	Mr. Larsen has served as a director since February 2019, and as Chairman of the Board, President and Chief Executive Officer (CEO) since July 2019. He previously served as President and Chief Operating Officer since January 2019, as President from January 2018 to January 2019, and as Senior Vice President (VP) from February 2014 to January 2018.
		IPL	Mr. Larsen has served as CEO since January 2019, as a director since February 2019, and as Chairman of the Board since July 2019. He previously served as Senior VP since February 2014.
		WPL	Mr. Larsen has served as CEO since January 2019, as a director since February 2019, and as Chairman of the Board since July 2019. He previously served as President since December 2010.
Robert J. Durian	51	Alliant Energy, IPL and WPL	Mr. Durian has served as Executive VP and Chief Financial Officer (CFO) since February 2020. He previously served as Senior VP and CFO since February 2019; as Senior VP, CFO and Treasurer from January 2018 to February 2019; and as VP, CFO and Treasurer from December 2016 to January 2018.
James H. Gallegos	61	Alliant Energy, IPL and WPL	Mr. Gallegos has served as Executive VP, General Counsel and Corporate Secretary since February 2020. He previously served as Senior VP, General Counsel and Corporate Secretary since February 2015.
David A. de Leon	59	Alliant Energy and IPL	Mr. de Leon has served as Senior VP since January 2019. He previously served as VP since April 2017 and as Director-Generation Construction from February 2014 to April 2017.
		WPL	Mr. de Leon has served as President since January 2019. He previously served as VP since April 2017 and as Director-Generation Construction from February 2014 to April 2017.
Terry L. Kouba	63	Alliant Energy and WPL	Mr. Kouba has served as Senior VP since January 2019. He previously served as VP since February 2014.
		IPL	Mr. Kouba has served as President since January 2019. He previously served as VP since February 2014.
Benjamin M. Bilitz	46	Alliant Energy, IPL and WPL	Mr. Bilitz has served as Chief Accounting Officer and Controller since December 2016.

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PART II

ITEM 5. MARKET FOR REGISTRANTS’ COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES

Common Stock Data - Alliant Energy’s common stock trades on the Nasdaq Global Select Market under the symbol “LNT,” and the closing sales price at December 31, 2021 was $61.47.

Shareowners - At December 31, 2021, there were 22,334 holders of record of Alliant Energy’s common stock, including holders through Alliant Energy’s Shareowner Direct Plan. Alliant Energy is the sole common shareowner of all 13,370,788 and 13,236,601 shares of IPL and WPL common stock, respectively, currently outstanding. As a result, there is no established public trading market for the common stock of either IPL or WPL.

Dividends - In November 2021, Alliant Energy announced an increase in its targeted 2022 annual common stock dividend to $1.71 per share, which is equivalent to a quarterly rate of $0.4275 per share, beginning with the February 2022 dividend payment. The timing and amount of future dividends is subject to an approved dividend declaration from Alliant Energy’s Board of Directors, and is dependent upon earnings expectations, capital requirements, and general financial business conditions, among other factors.

Common Stock Repurchases - A summary of Alliant Energy common stock repurchases for the quarter ended December 31, 2021 was as follows:

	Total Number	Average Price	Total Number of Shares	Maximum Number (or Approximate
	of Shares	Paid Per	Purchased as Part of	Dollar Value) of Shares That May
Period	Purchased (a)	Share	Publicly Announced Plan	Yet Be Purchased Under the Plan (a)
October 1 to October 31	3,833	$55.96	—	N/A
November 1 to November 30	2,800	56.28	—	N/A
December 1 to December 31	72	59.22	—	N/A
	6,705	56.13	—

(a)All shares were purchased on the open market and held in a rabbi trust under the DCP. There is no limit on the number of shares of Alliant Energy common stock that may be held under the DCP, which currently does not have an expiration date.

ITEM 6. [RESERVED]

ITEM 7. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

This MDA includes information relating to Alliant Energy, IPL and WPL, as well as AEF and Corporate Services. Where appropriate, information relating to a specific entity has been segregated and labeled as such. The following discussion and analysis should be read in conjunction with the Financial Statements and Notes included in this report. Unless otherwise noted, all “per share” references in MDA refer to earnings per diluted share. In addition, this MDA includes certain financial information for 2021 compared to 2020. Refer to MDA in the combined 2020 Form 10-K for details on certain financial information for 2020 compared to 2019.

OVERVIEW

Strategy and Mission

Alliant Energy’s mission is to deliver affordable energy solutions and exceptional service that its customers and communities count on - safely, efficiently, reliably and responsibly. The mission is supported by a strategy focused on meeting the evolving expectations of customers while providing an attractive return for investors, as well as serving its customers and building strong communities. This strategy includes the following key elements:

Providing affordable energy solutions to customers - Alliant Energy’s strategy focuses on affordable energy solutions that support retention and growth of its existing customers and attract new customers to its service territories.

Key Highlights -

•Alliant Energy’s Clean Energy Blueprints, also known as its cleaner energy strategy, is expected to result in cost savings for its utility customers through the planned transition away from coal-fired EGUs and incorporation of additional renewable energy, renewable tax credits for investments in renewable energy projects, and utilization of renewable project tax equity financing under the current tax regulations.

•WPL maintaining flat base rates in 2021 by utilizing Federal Tax Reform benefits and expected lower fuel costs to offset higher revenue requirements from rate base additions.

•IPL’s renewable energy rider became effective February 26, 2020, which allows for annual adjustments to electric rates charged to IPL’s retail electric customers for actual renewable energy costs incurred to fund IPL’s 1,000 MW of wind EGUs placed in service in 2019 and 2020, and related tax benefits, including production tax credits.

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•Providing $35 million of billing credits to IPL’s retail electric customers beginning in the third quarter of 2020 through June 2021, largely driven by Federal Tax Reform benefits for customers.

•Significant fuel cost reductions achieved in 2021 as a result of expansion of renewable generation and shortening the term of IPL’s DAEC PPA by 5 years.

•Issuance of new long-term debt in 2021 at historically low interest rates for IPL ($300 million of 3.1% senior debentures due 2051) and WPL ($300 million of 1.95% green bonds due 2031).

•Redemption of IPL’s 5.1% cumulative preferred stock in 2021.

•Levelized cost recovery mechanism for the remaining net book value of Edgewater Unit 5, which helps reduce customer costs in 2022 and 2023.

Making customer-focused investments - Alliant Energy’s strategic priorities include making significant customer-focused investments toward cleaner energy and sustainable customer solutions. Alliant Energy’s strategy drives a capital allocation process focused on: 1) transitioning its generation portfolio to meet the growing interest of customers for cleaner sources of energy, 2) upgrading its electric and gas distribution systems to strengthen safety and resiliency, as well as enable distributed energy solutions in its service territories, and 3) enhancing its customers’ experience with evolving technology and greater flexibility.

Key Highlights (refer to “Customer Investments” for details) -

•Planned development and acquisition of additional renewable energy, including approximately 1,100 MW of solar generation at WPL with in-service dates in 2022 and 2023, approximately 400 MW of solar generation at IPL with in-service dates in 2023 and 2024 and approximately 75 MW of battery storage in 2024 at IPL. In addition, IPL and WPL continue to evaluate additional opportunities to add more renewable generation, including repowering of existing wind farms and additional solar generation and distributed energy resources, including community solar and energy storage systems.

•IPL’s December 2021 completion of the fuel switch of the Burlington Generating Station (212 MW) from coal to natural gas.

Growing customer demand - Alliant Energy’s strategy supports expanding electric and gas usage in its service territories by promoting electrification initiatives and economic development in the communities it serves.

Key Highlights -

•WPL entered into a new wholesale power supply agreement, which was effective January 1, 2021 and brought approximately 55 MW of load to WPL’s electric system in 2021.

•Alliant Energy has various development-ready sites throughout Iowa and Wisconsin, including the 1,300-acre Big Cedar Industrial Center Mega-site in Cedar Rapids, Iowa, and the 730-acre Prairie View Industrial Center Super Park in Ames, Iowa, which are rail-served ready-to-build manufacturing and industrial sites in close proximity to the regional airport and interstate freeways and access IPL’s electric services. The Big Cedar Industrial Center Mega-site also accesses Travero’s rail-served warehouse in Iowa. In addition, the Beaver Dam Commerce Park is a 520-acre ready-to-build manufacturing and industrial site in Beaver Dam, Wisconsin, with access to commercial and freight airports, interstate freeways and WPL’s electric services.

COVID-19

The outbreak of COVID-19 has become a global pandemic and Alliant Energy’s service territories are not immune to the challenges presented by COVID-19. Despite these challenges, Alliant Energy, IPL and WPL continue to focus on providing the critical, reliable service their customers depend on, while emphasizing the health and welfare of their employees, customers and communities. Alliant Energy, IPL and WPL have not experienced significant impacts on their overall business operations, financial condition, results of operations or cash flows; however, the degree to which the COVID-19 pandemic may impact such items in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities. Alliant Energy has mitigated the impact of any sales declines from COVID-19 by accelerating planned cost transformation activities. Actual and potential impacts from COVID-19 include, but are not limited to, the following:

Operational and Supply Chain Impacts - Alliant Energy has modified certain business practices to help ensure the health and safety of its employees, contractors, customers and vendors consistent with orders and best practices issued by government and regulatory authorities. For example, Alliant Energy implemented its business continuity and pandemic plans for critical items and services, including travel restrictions, physical distancing, working-from-home protocols, and rescheduling of planned EGU outages. Alliant Energy also temporarily suspended service disconnects, waived late payment fees for its customers, and modified reconnect service procedures to ensure continuity of service for customers unable to pay their bills and consistency with regulatory orders.

While Alliant Energy has not experienced any significant issues to-date, it continues to monitor potential disruptions or constraints in materials and supplies from key suppliers. Alliant Energy’s construction projects are currently progressing as planned with added safety protocols, and while it continues to monitor its supply chain, Alliant Energy has experienced supply constraints and commodity inflation in the solar market. Alliant Energy’s wind farms under construction during the pandemic were placed in service in 2020 as previously planned to meet the timing requirements to qualify for the maximum renewable tax credits. In addition, Alliant Energy does not currently expect any material changes to its construction and acquisition expenditures plans disclosed in “Liquidity and Capital Resources” resulting from COVID-19.

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Alliant Energy has not experienced, and currently does not expect, an interruption in its ability to provide electric and natural gas services to its customers. Alliant Energy currently expects to incur incremental direct expenses related to certain of these operational and supply chain impacts but does not expect them to have a material impact on its results of operations.

Customer Impacts - COVID-19 has resulted in various travel restrictions and closures of commercial spaces and industrial facilities in Alliant Energy’s service territories, especially early on in the pandemic. While the total expected impact of COVID-19 on future sales is currently unknown, Alliant Energy experienced higher electric residential sales and lower electric commercial and industrial sales in 2020, and lower electric residential sales and higher electric commercial and industrial sales in 2021. In addition, Alliant Energy has not experienced a material increase in customer bankruptcies in 2020 or 2021.

Liquidity and Capital Resources Impacts - Alliant Energy maintains a single credit facility, which allows borrowing capacity to shift among Alliant Energy (at the parent company level), IPL and WPL, as needed. In addition, IPL maintains a sales of accounts receivable program as an alternative financing source; however, if customer arrears were to exceed certain levels, IPL’s access to the program may be restricted. Alliant Energy, IPL and WPL currently expect to maintain compliance with the financial covenants of the credit facility agreement, and Alliant Energy currently expects to maintain compliance with the financial covenants in AEF’s term loan credit agreement. In addition, Alliant Energy currently expects to have adequate liquidity to fulfill its contractual obligations, access to capital markets and continue with its planned quarterly dividend payments.

Credit Risk Impacts - Alliant Energy has not experienced any material negative impacts related to customer arrears and bad debts as a result of the pandemic; however, if government funds are no longer available for customers to help pay their utility bills, it may negatively impact Alliant Energy’s customers’ willingness and ability to pay, which could negatively impact Alliant Energy’s cash flows from operations. Currently, Alliant Energy does not anticipate any material credit risk related to its commodity transactions.

Legislative Impacts - Refer to “Legislative Matters” for discussion of legislation that was enacted in 2020 related to impacts from COVID-19.

RESULTS OF OPERATIONS

Results of operations include financial information prepared in accordance with GAAP as well as utility electric margins and utility gas margins, which are not measures of financial performance under GAAP. Utility electric margins are defined as electric revenues less electric production fuel, purchased power and electric transmission service expenses. Utility gas margins are defined as gas revenues less cost of gas sold. Utility electric margins and utility gas margins are non-GAAP financial measures because they exclude other utility and non-utility revenues, other operation and maintenance expenses, depreciation and amortization expenses, and taxes other than income tax expense.

Management believes that utility electric and gas margins provide a meaningful basis for evaluating and managing utility operations since electric production fuel, purchased power and electric transmission service expenses and cost of gas sold are generally passed through to customers, and therefore, result in changes to electric and gas revenues that are comparable to changes in such expenses. The presentation of utility electric and gas margins herein is intended to provide supplemental information for investors regarding operating performance. These utility electric and gas margins may not be comparable to how other entities define utility electric and gas margin. Furthermore, these measures are not intended to replace operating income as determined in accordance with GAAP as an indicator of operating performance.

Additionally, the table below includes EPS for Utilities and Corporate Services, ATC Holdings, and Non-utility and Parent, which are non-GAAP financial measures. Alliant Energy believes these non-GAAP financial measures are useful to investors because they facilitate an understanding of segment performance and trends, and provide additional information about Alliant Energy’s operations on a basis consistent with the measures that management uses to manage its operations and evaluate its performance.

Financial Results Overview - Alliant Energy’s net income and EPS attributable to Alliant Energy common shareowners were as follows (dollars in millions, except per share amounts):

	2021		2020
	Income (Loss)	EPS	Income (Loss)	EPS
Utilities and Corporate Services	$632	$2.52	$586	$2.36
ATC Holdings	31	0.12	34	0.14
Non-utility and Parent	(4)	(0.01)	(6)	(0.03)
Alliant Energy Consolidated	$659	$2.63	$614	$2.47

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Alliant Energy’s Utilities and Corporate Services income increased $46 million in 2021 compared to 2020. The increase was primarily due to higher earnings resulting from IPL’s and WPL’s increasing rate base, as well as higher sales due in part to the derecho windstorm in Iowa and COVID-19 sales impacts in 2020. These items were partially offset by higher depreciation expense and lower AFUDC.

Operating income and a reconciliation of utility electric and gas margins to the most directly comparable GAAP measure, operating income, was as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Operating income	$795	$740	$460	$410	$308	$306
Electric utility revenues	$3,081	$2,920	$1,752	$1,695	$1,329	$1,225
Electric production fuel and purchased power expenses	(642)	(652)	(295)	(352)	(347)	(300)
Electric transmission service expense	(537)	(449)	(367)	(298)	(170)	(151)
Utility Electric Margin (non-GAAP)	1,902	1,819	1,090	1,045	812	774
Gas utility revenues	456	373	265	208	191	165
Cost of gas sold	(258)	(182)	(149)	(99)	(109)	(83)
Utility Gas Margin (non-GAAP)	198	191	116	109	82	82
Other utility revenues	49	49	46	44	3	5
Non-utility revenues	83	74	—	—	—	—
Other operation and maintenance expenses	(676)	(670)	(362)	(375)	(268)	(254)
Depreciation and amortization expenses	(657)	(615)	(375)	(356)	(276)	(254)
Taxes other than income tax expense	(104)	(108)	(55)	(57)	(45)	(47)
Operating income	$795	$740	$460	$410	$308	$306

Operating Income Variances - Variances between periods in operating income for 2021 compared to 2020 were as follows (in millions):

	Alliant Energy	IPL	WPL
Total higher utility electric margin variance (Refer to details below)	$83	$45	$38
Total higher utility gas margin variance (Refer to details below)	7	7	—
Total (higher) lower other operation and maintenance expenses variance (Refer to details below)	(6)	13	(14)
Higher depreciation and amortization expense primarily due to additional plant in service in 2020 and 2021, including IPL’s new wind generation, and WPL’s West Riverside Energy Center and Kossuth wind farm	(42)	(19)	(22)
Other	13	4	—
	$55	$50	$2

Electric and Gas Revenues and Sales Summary - Electric and gas revenues (in millions), and MWh and Dth sales (in thousands), were as follows:

	Electric				Gas
	Revenues		MWhs Sold		Revenues		Dths Sold
	2021	2020	2021	2020	2021	2020	2021	2020
Alliant Energy
Retail	$2,771	$2,652	25,432	24,535	$413	$333	48,179	48,808
Sales for resale	243	204	5,805	6,046	N/A	N/A	N/A	N/A
Transportation/Other	67	64	71	71	43	40	99,179	102,790
	$3,081	$2,920	31,308	30,652	$456	$373	147,358	151,598
IPL
Retail	$1,633	$1,564	14,283	13,830	$237	$183	24,881	25,508
Sales for resale	74	88	1,807	3,485	N/A	N/A	N/A	N/A
Transportation/Other	45	43	35	34	28	25	40,738	39,543
	$1,752	$1,695	16,125	17,349	$265	$208	65,619	65,051
WPL
Retail	$1,138	$1,088	11,149	10,705	$176	$150	23,298	23,300
Sales for resale	169	116	3,998	2,561	N/A	N/A	N/A	N/A
Transportation/Other	22	21	36	37	15	15	58,441	63,247
	$1,329	$1,225	15,183	13,303	$191	$165	81,739	86,547

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Sales Trends and Temperatures - Alliant Energy’s retail electric sales volumes increased 4% in 2021 compared to 2020, primarily due to changes in temperatures, COVID-19 impacts in Alliant Energy’s service territories and impacts from the derecho windstorm in IPL’s service territory in August 2020, partially offset by the impact on sales of the additional day due to leap year in 2020. Alliant Energy’s retail gas sales volumes decreased 1% in 2021 compared to 2020, primarily due to changes in temperatures and the impact on sales of the additional day due to leap year in 2020, partially offset by COVID-19 impacts in Alliant Energy’s service territories. In 2021, changes in COVID-19 impacts resulted in decreases for retail electric residential sales volumes and increases for retail electric commercial and industrial sales.

Estimated increases (decreases) to electric and gas margins from the impacts of temperatures were as follows (in millions):

	Electric Margins		Gas Margins
	2021	2020	2021	2020
IPL	$12	$1	($1)	$—
WPL	7	3	(2)	(1)
Total Alliant Energy	$19	$4	($3)	($1)

Electric Sales for Resale - Electric sales for resale volume changes were largely due to changes in sales in the wholesale energy markets operated by MISO. These changes are impacted by several factors, including the availability and dispatch of Alliant Energy’s EGUs and electricity demand within these wholesale energy markets. Changes in sales for resale revenues were largely offset by changes in fuel-related costs, and therefore, did not have a significant impact on electric margins.

Gas Transportation/Other - Gas transportation/other sales volume changes were largely due to changes in the gas volumes supplied to Alliant Energy’s natural gas-fired EGUs caused by the availability and dispatch of such EGUs. Changes in these transportation/other revenues did not have a significant impact on gas margins.

Utility Electric Margin Variances - The following items contributed to increased (decreased) utility electric margins for 2021 compared to 2020 (in millions):

	Alliant Energy	IPL	WPL
Higher revenue requirements due to increasing rate base (a) (b)	$43	$29	$14
Estimated changes in sales volumes caused by temperatures	15	11	4
Higher wholesale margins at WPL partially due to a new wholesale customer in 2021	8	—	8
Lower revenues at IPL related to changes in recovery amounts for energy efficiency costs through the energy efficiency rider (mostly offset by changes in energy efficiency expense)	(14)	(14)	—
Other (includes higher temperature-normalized sales primarily due to the derecho windstorm in 2020 and COVID-19 impacts)	31	19	12
	$83	$45	$38

(a)IPL’s final retail electric base rate increase was effective February 26, 2020. Effective with final rates, the recovery of, and return on, IPL’s new wind generation placed in service in 2019 and 2020 is provided through the renewable energy rider. The final rate increase includes a reduction for anticipated production tax credits for IPL’s new wind generation. This reduction is expected to be offset by a reduction in income tax expense resulting from production tax credits recognized from this new wind generation. In September 2020, IPL made a buyout payment of $110 million in exchange for shortening the terms of its DAEC PPA by 5 years. The higher revenue requirements from the buyout payment, including a return on such costs, is being recovered from IPL’s retail customers from 2021 through the end of 2025. Refer to Note 2 for further discussion.

(b)In December 2020, the PSCW issued an order authorizing WPL to maintain its current retail electric base rates through the end of 2021. WPL utilized anticipated fuel-related cost savings and excess deferred income tax benefits in 2021 to offset the revenue requirement impacts of increasing electric rate base, including the Kossuth wind farm, which was placed in service in October 2020. The lower fuel expense benefits are recognized in electric margin and the additional amount of excess deferred income tax benefits is recognized as a reduction in income tax expense.

Utility Gas Margin Variances - The following items contributed to increased (decreased) utility gas margins for 2021 compared to 2020 (in millions):

	Alliant Energy	IPL	WPL
Higher revenues at IPL related to changes in recovery amounts for energy efficiency costs through the energy efficiency rider (mostly offset by changes in energy efficiency expense)	$7	$7	$—
Estimated changes in sales volumes caused by temperatures	(2)	(1)	(1)
Other	2	1	1
	$7	$7	$—

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Other Operation and Maintenance Expenses Variances - The following items contributed to (increased) decreased other operation and maintenance expenses for 2021 compared to 2020 (in millions):

	Alliant Energy	IPL	WPL
Higher generation operation and maintenance expenses	($17)	($12)	($5)
Credit loss adjustments in 2020 related to guarantees for an affiliate of Whiting Petroleum (Refer to Note 17(d))	(7)	—	—
Lower bad debt expense at IPL	13	13	—
Lower energy efficiency expense at IPL (primarily offset by changes in electric and gas revenues)	7	7	—
Other	(2)	5	(9)
	($6)	$13	($14)

Other Income and Deductions Variances - The following items contributed to (increased) decreased other income and deductions for 2021 compared to 2020 (in millions):

	Alliant Energy	IPL	WPL
Lower AFUDC primarily due to changes in CWIP balances related to IPL’s new wind generation, and WPL’s West Riverside Energy Center and Kossuth wind farm, placed in service in 2020	($30)	($15)	($15)
Other	8	7	—
	($22)	($8)	($15)

Income Taxes - Refer to Note 12 for details of effective income tax rates.

Preferred Dividend Requirements of IPL - Refer to Note 8 for details of the redemption of IPL’s 5.1% cumulative preferred stock in December 2021, including a $5 million non-cash charge recorded in 2021 related to this transaction.

Other Future Considerations - In addition to items discussed in this report, the following key items could impact Alliant Energy’s, IPL’s and WPL’s future financial condition or results of operations:

•Financing Plans - WPL and AEF currently expect to issue up to $600 million and $800 million of long-term debt, respectively, in 2022. WPL, AEF and Corporate Services have $250 million, $300 million and $75 million of long-term debt maturing in 2022, respectively. Alliant Energy currently expects to issue approximately $25 million of common stock in 2022 through its Shareowner Direct Plan.

•Common Stock Dividends - Alliant Energy announced a 6% increase in its targeted 2022 annual common stock dividend to $1.71 per share, which is equivalent to a quarterly rate of $0.4275 per share, beginning with the February 2022 dividend payment. The timing and amount of future dividends is subject to an approved dividend declaration from Alliant Energy’s Board of Directors, and is dependent upon earnings expectations, capital requirements, and general financial business conditions, among other factors.

•Higher Earnings on Increasing Rate Base - Alliant Energy and WPL currently expect an increase in earnings in 2022 compared to 2021 due to impacts from increasing revenue requirements related to investments in the utility business, including WPL’s solar investments. WPL’s increased revenue requirements are expected to be offset by higher income tax expense as a result of lower tax benefits.

•Depreciation and Amortization Expenses - Alliant Energy, IPL and WPL currently expect an increase in depreciation and amortization expenses in 2022 compared to 2021 due to property additions, including WPL’s expansion of solar generation.

•Interest Expense - Alliant Energy, IPL and WPL currently expect an increase in interest expense in 2022 compared to 2021 due to financings completed in 2021 and planned in 2022 as discussed above.

•Allowance for Funds Used During Construction - Alliant Energy and WPL currently expect AFUDC to increase in 2022 compared to 2021 primarily due to increased CWIP balances related to WPL’s solar generation.

•Preferred Dividend Requirements of IPL - Alliant Energy and IPL currently expect a decrease in preferred dividend requirements in 2022 compared to 2021 due to the redemption of IPL’s 5.1% cumulative preferred stock in December 2021.

CUSTOMER INVESTMENTS

Alliant Energy’s, IPL’s and WPL’s strategic priorities include making significant customer-focused investments toward cleaner energy and sustainable customer solutions. These priorities include:

Environmental Stewardship

Alliant Energy’s environmental stewardship is focused on meeting its customers’ energy needs in an economical, efficient, reliable and sustainable manner. Alliant Energy proactively considers future environmental compliance requirements and proposed regulations in its planning, decision-making, construction and ongoing operations activities. Alliant Energy is focused on executing a long-term strategy to deliver reliable and affordable energy with lower emissions independent of changing policies and political landscape. To achieve these long-term goals, Alliant Energy will transition away from coal-fired EGUs by

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incorporating renewable energy, distributed energy resources, energy efficiency, demand response, highly-efficient natural gas-fired EGUs and other emerging technologies such as energy storage. Alliant Energy’s voluntary environmental-related goals and achievements include the following:

•Exceeded its 2020 targets by reducing air emissions for sulfur dioxide by over 90%, nitrogen oxide by over 80% and mercury by over 90% from 2005 levels.

•By 2030, reduce CO2 emissions by 50% from its owned fossil-fueled EGUs and reduce electric utility water supply by 75% from 2005 levels, and transition 100% of its owned light-duty fleet vehicles to be electric, as well as partner to plant more than 1 million trees by the end of 2030.

•By 2040, eliminate all coal-fired EGUs from its generating fleet.

•By 2050, achieve an aspirational goal of net-zero CO2 emissions from the electricity it generates.

Future updates to sustainable energy plans and attaining these goals will depend on future economic developments, evolving energy technologies and emerging trends in Alliant Energy’s service territories.

Renewable Generation

Alliant Energy has developed Clean Energy Blueprints, or its cleaner energy strategy, as a guide to meet customer demand for affordable, reliable and cleaner energy in Iowa and Wisconsin. This strategy includes the planned development and acquisition of additional renewable energy, including approximately 1,100 MW of solar generation at WPL with in-service dates in 2022 and 2023, approximately 400 MW of solar generation at IPL with in-service dates in 2023 and 2024 and approximately 75 MW of battery storage in 2024 at IPL. In addition, WPL’s plans include up to 300 MW of additional capacity. Alliant Energy, IPL and WPL continue to evaluate additional opportunities to add more renewable generation, repowering of existing wind farms, and distributed energy resources, including community solar and energy storage systems. Estimated capital expenditures for these planned projects for 2022 through 2025 are included in the “Renewable projects” line in the construction and acquisition table in “Liquidity and Capital Resources.” These estimates include current expectations for higher costs for various projects, as supply constraints and commodity inflation continue to be prevalent in the solar market. IPL and WPL currently assume that a portion of the construction costs for the new solar generation will be financed by a tax equity partner, which is discussed in “IPL and WPL Solar Project Tax Equity Financing” in “Liquidity and Capital Resources.” In addition, Alliant Energy completed the construction and acquisition of approximately 1,200 MW of wind generation in aggregate (approximately 1,000 MW at IPL and approximately 200 MW at WPL) from 2018 through 2020.

WPL’s Solar Generation and Distributed Energy Resources - In June 2021, WPL received an order from the PSCW for its first CA authorizing WPL to acquire, own, and operate 675 MW of new solar generation in the following Wisconsin counties: Grant (200 MW), Sheboygan (150 MW), Wood (150 MW), Jefferson (75 MW), Richland (50 MW) and Rock (50 MW). In July 2021, WPL notified the PSCW that it currently expects estimated construction costs and related rate base additions associated with its 675 MW of new solar generation will exceed amounts approved by the PSCW in June 2021 by approximately 7-10%. In September 2021 and January 2022, WPL filed revised estimated construction costs and related rate base additions for its second CA with the PSCW for approval to acquire, construct, own, and operate up to 414 MW of new solar generation in the following Wisconsin counties: Dodge (150 MW), Waushara (99 MW), Rock (65 MW), Grant (50 MW) and Green (50 MW). These projects in the first and second CAs are expected to be placed in service in 2022 and 2023. The 1,089 MW of new solar generation would replace energy and capacity being eliminated with the planned retirement of the coal-fired Edgewater Generating Station (414 MW) by early 2023, and Columbia Unit 1 by the end of 2023 and Columbia Unit 2 by the end of 2024 (595 MW in aggregate), which are the last coal-fired EGUs at WPL. The retirement of these coal-fired EGUs supports Alliant Energy’s strategy, which is focused on meeting its customers’ energy needs in an economical, efficient, reliable and sustainable manner. As a result of WPL’s neighboring utilities’ anticipated purchase of a partial ownership interest in West Riverside and any requirements resulting from MISO’s resource adequacy proposal that was issued in 2021, WPL anticipates additional capacity needs by 2024, which is expected to result in additional renewable energy resources and energy storage systems. WPL currently expects to request approval from the PSCW in 2022 for up to 300 MW of additional capacity.

IPL’s Solar Generation and Distributed Energy Resources - In November 2021, IPL filed for advance rate-making principles with the IUB for up to 400 MW of solar generation with in-service dates in 2023 and 2024 and approximately 75 MW of battery storage in 2024. The advance rate-making principles filing included requests for a fixed cost cap of $1,575/kilowatt, including AFUDC and transmission upgrade costs among other costs, and a return on common equity of 11.40%, and proposes that a portion of the construction be financed by tax equity partners. In addition, the filing included a request that any costs incurred in excess of the cost cap be incorporated into rates if determined to be reasonable and prudent. The 400 MW of new solar generation and 75 MW of battery storage would help replace a portion of the energy and capacity expected to be eliminated with the planned retirement of the coal-fired Lansing Generating Station (275 MW) by the end of 2022 and the expected reduction of energy and capacity resulting from the December 2021 fuel switch of the Burlington Generating Station (212 MW) from coal to natural gas. In addition, IPL’s plans include additional renewables and distributed energy resources, including community solar and energy storage systems, to add energy and capacity.

Complementary Generation Investments

WPL’s West Riverside Natural Gas-fired Generating Station - In 2020, WPL completed the construction of West Riverside, a 723 MW natural gas-fired combined-cycle EGU in Beloit, Wisconsin. WPL entered into agreements with neighboring utilities and electric cooperatives that provide each of them options to purchase a partial ownership interest in West Riverside. The

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purchase price for such options is based on the ownership interest acquired and the net book value of West Riverside on the date of the purchase. The exercise of the WPSC and MGE options is subject to PSCW approval, which is currently expected by early 2023, and the timing and ownership amounts of the options are as follows:

Counterparty	Option Amount and Timing
Wisconsin Public Service Corporation (WPSC)	100 MW were exercised January 2022; additionally, up to 100 MW may be exercised between May 15, 2022 and May 15, 2024 (a)
Madison Gas and Electric Company (MGE)	25 MW were exercised January 2022; additionally, up to 25 MW may be exercised between May 15, 2022 and May 15, 2025
Electric cooperatives	Approximately 60 MW were acquired January 2018

(a)Upon WPSC’s exercise of its options, WPL may exercise reciprocal options, subject to approval by the PSCW, to purchase up to 200 MW of any natural-gas combined-cycle EGU that either WPSC or its affiliated utility, Wisconsin Electric Power Company, places in service prior to May 2030.

Plant Retirements and Fuel Switching - The current strategy includes the retirement, or fuel switch from coal to natural gas, of various EGUs in the next several years. In December 2021, completed the fuel switch of the Burlington Generating Station (212 MW) from coal to natural gas. IPL currently expects to retire the coal-fired Lansing Generating Station (275 MW) by the end of 2022. WPL currently expects to retire the coal-fired Edgewater Generating Station (414 MW) by early 2023, Columbia Unit 1 by the end of 2023 and Columbia Unit 2 by the end of 2024. Alliant Energy, IPL and WPL are working with MISO, state regulatory commissions and other regulatory agencies, as required, to determine the timing of these actions, which are subject to change depending on operational, regulatory, market and other factors. Refer to Note 3 for additional details on these EGUs.

Other Customer-focused Investments

Electric and Gas Distribution Systems - Customer-focused investments include replacing, modernizing and upgrading infrastructure in the electric and gas distribution systems. Electric system investments will focus on areas such as improving reliability and resiliency with more underground electric distribution and enabling distributed energy solutions with higher capacity lines. Gas system investments will focus on pipeline replacement to ensure safety and pipeline expansion to support reliability and economic development. Estimated capital expenditures for expected and current electric and gas distribution infrastructure projects for 2022 through 2025 are included in the “Electric and gas distribution systems” lines in the construction and acquisition expenditures table in “Liquidity and Capital Resources.”

Fiber Optic Telecommunication Network - Alliant Energy is currently installing fiber optic routes between its facilities to enhance its communications network to improve resiliency and reliability of, and enable and strengthen, the integrated grid network to help serve its customers.

Gas Pipeline Expansion - IPL and WPL currently expect to make investments to extend various gas distribution systems to provide natural gas to unserved or underserved areas in their service territories.

Gas Pipeline Safety - In 2019, the Pipeline and Hazardous Materials Safety Administration published a final rule that updates safety requirements for gas transmission pipelines, and various updated procedures were implemented in 2020. Plans to address certain requirements for specific pipelines were developed and implemented, and remediation efforts must be completed by July 2035. In anticipation of these rule changes, Alliant Energy, IPL and WPL have been proactively replacing certain of IPL’s transmission pipelines and making modifications to certain of WPL’s transmission pipelines. Alliant Energy, IPL, and WPL also continue to evaluate the impact of this final rule and resulting remediation plans on their financial condition and results of operations.

Technology - Alliant Energy, IPL and WPL currently plan to make investments in technology to enhance productivity and efficiency through automation, customer self-service and telework. Estimated capital expenditures for expected and current technology projects for 2022 through 2025 are included in the “Other” line in the construction and acquisition expenditures table in “Liquidity and Capital Resources.”

Non-utility business - Alliant Energy continues to explore growth of its Travero businesses and other limited scope opportunities outside of, but complimentary to, Alliant Energy’s core utility business. This non-utility strategy continues to evolve through exploration of modest strategic opportunities that are accretive to earnings and cash flows.

RATE MATTERS

Rate Reviews

Retail Base Rate Filings - Base rate changes reflect both returns on additions to infrastructure and recovery of changes in costs incurred or expected to be incurred. Given that a portion of the rate changes will offset changes in costs, revenues from rate changes should not be expected to result in an equal change in net income for either IPL or WPL.

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WPL’s Retail Electric and Gas Rate Reviews (2022/2023 Forward-looking Test Period) - In December 2021, the PSCW issued an order authorizing annual base rate increases of $114 million and $15 million for WPL’s retail electric and gas customers, respectively, covering the 2022/2023 forward-looking Test Period, which was based on a stipulated agreement between WPL and certain intervenor groups. The key drivers for the annual base rate increases include higher retail fuel-related costs in 2022, lower excess deferred income tax benefits in 2022 and 2023 and revenue requirement impacts of increasing electric and gas rate base, including investments in solar generation. In addition, the PSCW authorized WPL to receive a recovery of and a return on the remaining net book value of Edgewater Unit 5 through 2023. Retail electric rate changes were effective on January 1, 2022 and extend through the end of 2023. Retail gas rate changes were effective on January 1, 2022 and extend through the end of 2022. WPL expects to file a limited reopener by August 2022 to adjust retail gas rates for the 2023 forward-looking Test Period, which will be limited to changes in weighted average cost of capital, updated depreciation rates and modifications to certain regulatory asset and regulatory liability amortizations. WPL’s settlement extends, with certain modifications, an earnings sharing mechanism through 2023. Under the earnings sharing mechanism, WPL will defer a portion of its earnings if its annual regulatory return on common equity exceeds 10.25% during the 2022/2023 Test Period. WPL must defer 50% of its excess earnings between 10.25% and 10.75%, and 100% of any excess earnings above 10.75%. Through 2023, any such deferral is required to be offset against the remaining net book value of Edgewater Unit 5, which is currently expected to be retired by early 2023.

IPL’s Retail Electric and Gas Rate Reviews (2020 Forward-looking Test Period) - In 2019, IPL filed retail electric and gas rate review requests with the IUB covering the 2020 forward-looking Test Period. In January 2020, IPL received an order from the IUB approving IPL’s proposed settlement for its retail electric rate review. Final retail electric rates were effective February 26, 2020. In December 2019, IPL received an order from the IUB approving IPL’s proposed settlement for its retail gas rate review. Final retail gas rates were effective January 10, 2020. In 2021, the IUB issued orders for IPL’s 2020 forward-looking Test Period electric and gas subsequent proceedings, which compared actual revenues and costs to those initially forecasted by IPL, and authorized IPL to main its current retail electric and gas rates. Refer to Note 2 for details.

Rate Review Details - Details related to IPL’s and WPL’s key jurisdictions were as follows:

		Average	Authorized Return	Common Equity
	Regulatory	Rate Base	on Common	Component of Regulatory	Effective
	Body	(in millions)	Equity (a)	Capital Structure	Date
IPL Retail Electric (2020 Test Period)
Marshalltown (b)	IUB	$559	11.00%	51.0%	2/26/2020
Emery (b)	IUB	165	12.23%	51.0%	2/26/2020
Whispering Willow - East (b)	IUB	163	11.70%	51.0%	2/26/2020
Renewable energy rider (c)	IUB	1,573	10.40%	51.0%	2/9/2021
Other (b)	IUB	3,767	9.50%	51.0%	2/26/2020
IPL Retail Gas (2020 Test Period) (b)	IUB	557	9.60%	51.0%	1/10/2020
IPL Wholesale Electric	FERC	198	10.97%	51.0%	1/1/2021
WPL Retail Electric and Gas
Electric (2022 Test Period) (d)	PSCW	4,196	10.00%	53.8%	1/1/2022
Gas (2022 Test Period) (d)	PSCW	471	10.00%	53.8%	1/1/2022
WPL Wholesale Electric	FERC	373	10.90%	55.0%	1/1/2021

(a)Authorized returns on common equity may not be indicative of actual returns earned or projections of future returns.

(b)Average rate base amounts reflect IPL’s allocated retail share of rate base and do not include CWIP, and were calculated using a forecasted 13-month average for the test period.

(c)Average rate base amounts recovered through IPL’s renewable energy rider mechanism include construction costs incurred to fund IPL’s 1,000 MW of wind generation facilities placed in service in 2019 and 2020 (11.00% return on common equity), production tax credit carryforwards for the 1,000 MW of wind generation facilities (5.00% return on common equity) and certain transmission facilities classified as intangible assets (9.50% return on common equity), and were calculated using a 13-month average.

(d)Average rate base amounts reflect WPL’s allocated retail share of rate base and do not include CWIP or a cash working capital allowance, and were calculated using a forecasted 13-month average for the test period. The PSCW provides a return on selected CWIP and a cash working capital allowance by adjusting the percentage return on rate base.

LEGISLATIVE MATTERS

In March 2020, the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) was enacted. The most significant provision of the CARES Act for Alliant Energy relates to an acceleration of refunds of existing alternative minimum tax credits to increase liquidity. In 2020, Alliant Energy received $11 million of credits that otherwise would have been received in 2021 and 2022. In addition, Alliant Energy deferred certain 2020 payroll taxes to 2021 and 2022. The CARES Act also provides additional funding to the Low Income Home Energy Assistance Program, which assists certain of Alliant Energy’s customers with managing their energy costs, as well as financial support for certain of Alliant Energy’s residential, small business and non-profit customers.

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In December 2020, the Coronavirus Response and Relief Supplemental Appropriations Act of 2021 (CRRSA) was enacted. The most significant provision of the CRRSA Act for Alliant Energy relates to the extension of certain renewable tax credits, and as a result, Alliant Energy will evaluate additional opportunities for repowering of its existing wind farms and additional solar projects beyond 2023. The CRRSA Act also provides additional funding to the Low Income Home Energy Assistance Program, as well as financial support for certain of Alliant Energy’s residential, small business and non-profit customers.

In March 2021, the American Rescue Plan Act of 2021 (Act) was enacted. The most significant provision of the Act for Alliant Energy is reduced minimum pension plan funding requirements, which Alliant Energy adopted in August 2021. The Act also provides additional funding to the Low Income Home Energy Assistance Program, which assists certain of Alliant Energy’s customers with managing their energy costs, as well as provides financial support for certain of Alliant Energy’s residential, small business and non-profit customers.

In April 2021, legislation was enacted in Iowa prohibiting counties and cities from regulating the sale of natural gas and propane, which supports IPL’s ability to provide gas utility service to a diversified base of retail customers and industries.

In November 2021, the Infrastructure Investment and Jobs Act (IIJA Act) was enacted. The most significant provisions of the IIJA Act for Alliant Energy relate to a variety of infrastructure-related priorities, including transportation, environmental, energy and broadband infrastructure. In addition, the IIJA Act is intended to accelerate research, development, demonstration and deployment of carbon-free technologies, including hydrogen and carbon capture and storage.

LIQUIDITY AND CAPITAL RESOURCES

Overview - Alliant Energy, IPL and WPL expect to maintain adequate liquidity to operate their businesses and implement their strategy as a result of operating cash flows generated by their utility business, and available capacity under a single revolving credit facility and IPL’s sales of accounts receivable program, supplemented by periodic issuances of long-term debt and Alliant Energy equity securities. As summarized below, Alliant Energy, IPL and WPL believe they have the ability to generate and obtain adequate amounts of cash to meet their requirements and plans for cash in the next 12 months and beyond.

COVID-19 Considerations - Refer to “Overview” in MDA for discussion of COVID-19 and the impacts on Alliant Energy’s, IPL’s and WPL’s liquidity and capital resources.

Liquidity Position - At December 31, 2021, Alliant Energy had $39 million of cash and cash equivalents, $485 million ($171 million at the parent company, $250 million at IPL and $64 million at WPL) of available capacity under the single revolving credit facility and $109 million of available capacity at IPL under its sales of accounts receivable program.

Capital Structure - Alliant Energy, IPL and WPL plan to maintain debt-to-total capitalization ratios that are consistent with investment-grade credit ratings. IPL and WPL expect to maintain capital structures consistent with their authorized levels. Capital structures as of December 31, 2021 were as follows (Common Equity (CE); Long-term Debt (including current maturities) (LD); Short-term Debt (SD)):

Alliant Energy, IPL and WPL intend to manage their capital structures and liquidity positions in such a way that facilitates their ability to raise funds reliably and on reasonable terms and conditions, while maintaining capital structures consistent with those approved by regulators. In addition to capital structures, other important factors used to determine the characteristics of future financings include financial coverage ratios, capital spending plans and solar construction that is expected to be partially financed by tax equity partners, regulatory orders and rate-making considerations, levels of debt imputed by rating agencies, market conditions, the impact of tax initiatives and legislation, and any potential proceeds from asset sales. The PSCW factors certain imputed debt adjustments, including certain lease obligations, in establishing a regulatory capital structure as part of WPL’s retail rate reviews. The IUB does not make any explicit adjustments for imputed debt in establishing capital ratios used in determining customer rates, although such adjustments are considered by IPL in recommending an appropriate capital structure. Debt imputations by rating agencies include, among others, pension and OPEB obligations and the sales of accounts receivable program.

Credit and Capital Markets - Alliant Energy, IPL and WPL maintain a single revolving credit facility to provide backstop liquidity to their commercial paper programs, and ensure a committed source of liquidity in the event the commercial paper market becomes disrupted. In addition, IPL maintains a sales of accounts receivable program as an alternative financing source; however, if customer arrears were to exceed certain levels, IPL’s access to the program may be restricted.

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Primary Sources and Uses of Cash - Alliant Energy’s most significant source of cash is from electric and gas sales to IPL’s and WPL’s customers. Cash from these sales reimburses IPL and WPL for prudently-incurred expenses to provide service to their utility customers and generally provides IPL and WPL a return of and a return on the assets used to provide such services. Capital needed to retire debt and fund capital expenditures related to large strategic projects is expected to be met primarily through external financings.

Cash Flows - Selected information from the cash flows statements was as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Cash, cash equivalents and restricted cash, January 1	$56	$18	$50	$9	$3	$4
Cash flows from (used for):
Operating activities	582	501	153	(6)	371	466
Investing activities	(728)	(951)	91	(301)	(716)	(613)
Financing activities	130	488	(260)	348	344	146
Net increase (decrease)	(16)	38	(16)	41	(1)	(1)
Cash, cash equivalents and restricted cash, December 31	$40	$56	$34	$50	$2	$3

Operating Activities - The following items contributed to increased (decreased) operating activity cash flows for 2021 compared to 2020 (in millions):

	Alliant Energy	IPL	WPL
DAEC PPA amendment buyout payment in 2020 (Refer to Note 2)	$110	$110	$—
Credits issued to IPL’s retail electric customers in 2020 through its transmission cost rider for amounts previously collected in rates (Refer to Note 2)	42	42	—
Increased collections from IPL’s and WPL’s retail customers caused by temperature impacts on electric and gas sales	13	10	3
Changes in levels of production fuel	4	21	(17)
Changes in the sales of accounts receivable at IPL	(70)	(70)	—
Timing of WPL’s fuel-related cost recoveries from customers	(27)	—	(27)
Refunds received in 2020 related to the MISO transmission owner return on equity complaint FERC orders	(20)	(15)	(5)
Credits issued to IPL’s retail electric customers in 2021 through its transmission cost rider for refunds received in 2020 for MISO transmission owner return on equity complaints	(14)	(14)	—
Changes in income taxes paid/refunded	(8)	65	(51)
Other (primarily due to other changes in working capital)	51	10	2
	$81	$159	($95)

Income Tax Payments and Refunds - Income tax (payments) refunds, including refunds of alternative minimum tax credits, were as follows (in millions):

	2021	2020
IPL	$47	($18)
WPL	(38)	13
Other subsidiaries	(12)	10
Alliant Energy	($3)	$5

Alliant Energy, IPL and WPL currently do not expect to make any significant federal income tax payments through 2023 based on their current federal net operating loss and credit carryforward positions. While no significant federal income tax payments through 2023 are expected to occur, some tax payments and refunds may occur for state taxes and between consolidated group members (including IPL and WPL) under the tax sharing agreement between Alliant Energy and its subsidiaries. Refer to Note 12 for discussion of the carryforward positions.

Pension Plan Contributions - Alliant Energy, IPL and WPL currently expect to make $2 million, $0 and $0 of pension plan contributions in 2022, respectively, based on the funded status and assumed return on assets for each plan as of the December 31, 2021 measurement date. Refer to Note 13(a) for discussion of pension plan contributions in 2021 and the current funded levels of pension plans.

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Investing Activities - The following items contributed to increased (decreased) investing activity cash flows for 2021 compared to 2020 (in millions):

	Alliant Energy	IPL	WPL
(Higher) lower utility construction and acquisition expenditures (a)	$223	$303	($80)
Changes in the amount of cash receipts on sold receivables	44	44	—
Refund from ATC in 2020 for construction deposits WPL previously provided to ATC for transmission network upgrades for West Riverside	(42)	—	(42)
Other	(2)	45	19
	$223	$392	($103)

(a)Largely due to lower expenditures for IPL’s and WPL’s expansion of wind generation, IPL’s and WPL’s electric and gas distribution systems and WPL’s West Riverside Energy Center, partially offset by higher expenditures for WPL’s solar generation.

Construction and Acquisition Expenditures - Construction and acquisition expenditures and financing plans are reviewed, approved and updated as part of the strategic planning process. Changes may result from a number of reasons, including regulatory requirements, changing legislation, not obtaining favorable and acceptable regulatory approval on certain projects, improvements in technology and improvements to ensure reliability of the electric and gas distribution systems. Alliant Energy, IPL and WPL have not yet entered into contractual commitments relating to the majority of their anticipated future construction and acquisition expenditures. As a result, they have some discretion with regard to the level and timing of these expenditures. The table below summarizes anticipated construction and acquisition expenditures (in millions), which are focused on the transition to cleaner energy and strengthening the resiliency of Alliant Energy’s, IPL’s and WPL’s electric grid. Cost estimates represent Alliant Energy’s, IPL’s and WPL’s portion of construction expenditures and exclude AFUDC and capitalized interest, if applicable. Such estimates do not reflect the assumption that a portion of the construction is expected to be financed by tax equity partners, which is described in more detail below in “IPL and WPL Solar Project Tax Equity Financing.” Refer to “Customer Investments” for further discussion of certain key projects impacting construction and acquisition plans related to the utility business.

	Alliant Energy				IPL				WPL
	2022	2023	2024	2025	2022	2023	2024	2025	2022	2023	2024	2025
Generation:
Renewable projects	$845	$980	$1,135	$800	$80	$150	$505	$450	$765	$830	$630	$350
Other	100	90	95	80	55	50	45	35	45	40	50	45
Distribution:
Electric systems	435	555	590	615	210	300	330	350	225	255	260	265
Gas systems	75	110	75	75	30	35	35	35	45	75	40	40
Other	185	190	190	185	30	30	35	35	25	20	35	30
	$1,640	$1,925	$2,085	$1,755	$405	$565	$950	$905	$1,105	$1,220	$1,015	$730

Alliant Energy’s and IPL’s construction and acquisition expenditures for renewable projects in 2022 through 2024 include approximately $300 million in aggregate, a portion of which is expected to be reflected as “Other” cash flows used for investing activities in Alliant Energy’s and IPL’s cash flows.

West Riverside Options - WPL entered into agreements with neighboring utilities that provide them options to purchase a partial ownership interest in West Riverside. Upon exercise of such options, WPL will receive proceeds from the sale. Refer to “Customer Investments” for additional information, including timing for the actual and potential exercise of options.

Financing Activities - The following items contributed to increased (decreased) financing activity cash flows for 2021 compared to 2020 (in millions):

	Alliant Energy	IPL	WPL
Lower net proceeds from issuance of long-term debt	($650)	($100)	($50)
Lower net proceeds from common stock issuances	(219)	—	—
Payments to redeem cumulative preferred stock of IPL in 2021	(200)	(200)	—
Higher common stock dividends	(26)	(164)	(8)
Lower payments to retire long-term debt	649	200	150
Net changes in the amount of commercial paper outstanding	74	—	(110)
Higher (lower) capital contributions from IPL’s and WPL’s parent company, Alliant Energy	—	(354)	220
Other	14	10	(4)
	($358)	($608)	$198

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IPL and WPL Solar Project Tax Equity Financing - IPL and WPL each propose to own and operate their planned solar projects, discussed in “Customer Investments,” which are currently expected to qualify for 26% to 30% investment tax credits, through a tax equity partnership, with approximately 25% to 45% of the construction costs financed with capital from the tax equity partner. This would allow IPL’s and WPL’s customers to share the costs of the solar projects with an investment partner for 10 years or less, while ensuring their customers receive energy, capacity, and renewable energy credit benefits from the projects. IPL and WPL would expect to purchase the tax equity partner’s interest in the solar projects within 10 years of operation, and then convert to a traditional ownership structure for the remainder of the useful life of the projects. Assuming a portion of the construction costs are financed by the tax equity partner, IPL would receive approximately $25 million in 2023, $200 million in 2024 and $60 million in 2025 from the tax equity partner, and WPL would receive approximately $165 million in 2022, $420 million in 2023, $230 million in 2024 and $190 million in 2025 from the tax equity partner. Changes to proposed solar project tax equity financing may result from a number of reasons, including changing legislation. IPL and WPL would expect to include their portion of capital expenditures, less the amounts financed by the tax equity partner, in their respective rate base.

FERC and Public Utility Holding Company Act Financing Authorizations - Under the Public Utility Holding Company Act of 2005, FERC has authority over the issuance of utility securities, except to the extent that a public utility’s primary state regulatory commission has retained jurisdiction over such matters. FERC currently has authority over the issuance of securities by IPL. FERC does not have authority over the issuance of securities by Alliant Energy, WPL, AEF or Corporate Services. In 2021, IPL received authorization from FERC to issue securities in 2022 and 2023 as follows (in millions):

Long-term debt securities issuances in aggregate	$700
Short-term debt securities outstanding at any time (including borrowings from its parent)	400
Preferred stock issuances in aggregate	300

State Regulatory Financing Authorizations - In 2017, WPL received authorization from the PSCW to have up to $400 million of short-term borrowings and/or letters of credit outstanding at any time through the earlier of the expiration date of WPL’s credit facility agreement (including extensions) or December 2024. As of December 31, 2021, WPL also had authority to issue up to $700 million of long-term debt securities in aggregate through December 2023 pursuant to a September 2020 PSCW order.

Shelf Registrations - Alliant Energy, IPL and WPL have current shelf registration statements on file with the SEC for availability to issue unspecified amounts of securities through December 2023. Alliant Energy’s shelf registration statement may be used to issue common stock, debt and other securities. IPL’s and WPL’s shelf registration statements may be used to issue preferred stock and debt securities.

Common Stock Dividends - Payment of common stock dividends is subject to dividend declaration by Alliant Energy’s Board of Directors and is dependent upon, among other factors, regulatory limitations, earnings, cash flows, capital requirements and general financial condition of subsidiaries. Alliant Energy’s general long-term goal is to maintain a dividend payout ratio that is competitive with the industry average. Based on that, Alliant Energy’s goal is to maintain a dividend payout ratio of approximately 60% to 70% of consolidated earnings from continuing operations. Refer to “Results of Operations” for discussion of expected common stock dividends in 2022.

Common Stock Issuances - Refer to Note 7 for discussion of common stock issuances by Alliant Energy in 2020 and 2021, and “Results of Operations” for discussion of expected issuances of common stock in 2022.

Short-term Debt - In December 2021, Alliant Energy, IPL and WPL entered into a single revolving credit facility agreement, which expires in December 2026 and is discussed in Note 9(a). There are currently 13 lenders that participate in the credit facility, with respective commitments ranging from $20 million to $130 million. Subject to certain conditions, Alliant Energy, IPL and WPL may exercise two extension options, each extending the maturity date by one year. The credit facility has a provision to expand the facility size up to an additional $300 million, for a potential total commitment of $1.3 billion, subject to lender approval for Alliant Energy and subject to lender and regulatory approvals for IPL and WPL.

The credit agreement contains customary events of default, including a cross-default provision that would be triggered if Alliant Energy or certain of its significant subsidiaries (including IPL and WPL) defaults on debt (other than non-recourse debt) totaling $100 million or more. IPL and WPL are subject to a similar cross-default provision with respect to their own respective consolidated debt. A default by Alliant Energy or its non-utility subsidiaries would not trigger a cross-default at IPL or WPL, nor would a default by either of IPL or WPL constitute a cross-default event for the other. If an event of default under the credit agreement occurs and is continuing, then the lenders may declare any outstanding obligations of the defaulting borrower under the credit agreement immediately due and payable.

The single credit facility agreement contains a financial covenant, which requires Alliant Energy, IPL and WPL to maintain certain debt-to-capital ratios in order to borrow under the credit facility. AEF’s term loan credit agreement contains a financial covenant, which requires Alliant Energy to maintain a certain debt-to-capital ratio in order to borrow under the term loan credit agreement. The required debt-to-capital ratios compared to the actual debt-to-capital ratios at December 31, 2021 were as follows:

	Alliant Energy	IPL	WPL
Requirement, not to exceed	65%	65%	65%
Actual	57%	49%	49%

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The debt component of the capital ratios includes, when applicable, long- and short-term debt (excluding non-recourse debt and hybrid securities to the extent the total carrying value of such hybrid securities does not exceed 15% of consolidated capital of the applicable borrower), finance lease obligations, certain letters of credit, guarantees of the foregoing and new synthetic leases. Unfunded vested benefits under qualified pension plans and sales of accounts receivable are not included in the debt-to-capital ratios. The equity component of the capital ratios excludes accumulated other comprehensive income (loss).

Long-term Debt - Refer to Note 9(b) for discussion of issuances and retirements of long-term debt in 2021 and “Results of Operations” for discussion of expected issuances of long-term debt in 2022. In 2020, IPL issued $400 million of 2.3% senior debentures due 2030, and a portion of the proceeds from the issuance was used by IPL to retire its $200 million 3.65% senior debentures that matured in 2020. In 2020, WPL issued $350 million of 3.65% debentures due 2050, and a portion of the proceeds from the issuance was used by WPL to reduce borrowings under the single revolving credit facility. In 2020, AEF entered into a $300 million variable-rate term loan credit agreement and used the borrowings under this agreement to retire its $300 million variable-rate term loan credit agreement that expired in 2020. In 2020, AEF issued $200 million of 1.4% senior notes due 2026, and a portion of the proceeds from the issuance was used to reduce Alliant Energy’s outstanding commercial paper.

Impact of Credit Ratings on Liquidity and Collateral Obligations -

Ratings Triggers - The long-term debt of Alliant Energy and its subsidiaries is not subject to any repayment requirements as a result of explicit credit rating downgrades or so-called “ratings triggers.” However, Alliant Energy and its subsidiaries are parties to various agreements that contain provisions dependent on credit ratings. In the event of a significant downgrade, Alliant Energy or its subsidiaries may need to provide credit support, such as letters of credit or cash collateral equal to the amount of any exposure, or may need to unwind contracts or pay underlying obligations. In the event of a significant downgrade, management believes Alliant Energy, IPL and WPL have sufficient liquidity to cover counterparty credit support or collateral requirements under these various agreements. In addition, a downgrade in the credit ratings of Alliant Energy, IPL or WPL could also result in them paying higher interest rates in future financings, reduce flexibility with future financing plans, reduce their pool of potential lenders, increase their borrowing costs under existing credit facilities or limit their access to the commercial paper market. Credit ratings and outlooks as of the date of this report are as follows:

		Standard & Poor’s Ratings Services	Moody’s Investors Service
Alliant Energy:	Corporate/issuer	A-	Baa2
	Commercial paper	A-2	P-2
	Senior unsecured long-term debt	N/A	N/A
	Outlook	Stable	Stable
IPL:	Corporate/issuer	A-	Baa1
	Commercial paper	A-2	P-2
	Senior unsecured long-term debt	A-	Baa1
	Outlook	Stable	Stable
WPL:	Corporate/issuer	A	A3
	Commercial paper	A-1	P-2
	Senior unsecured long-term debt	A	A3
	Outlook	Stable	Stable

Standard & Poor’s Ratings Services and Moody’s Investors Service issued credit ratings of BBB+ and Baa2, respectively, for the senior notes issued by AEF in 2018 and 2020 (with Alliant Energy as guarantor). Credit ratings are not recommendations to buy or sell securities and are subject to change, and each rating should be evaluated independently of any other rating. Each of Alliant Energy, IPL or WPL assumes no obligation to update their respective credit ratings. Refer to Note 15 for additional information on ratings triggers for commodity contracts accounted for as derivatives.

Off-Balance Sheet Arrangements -

Special Purpose Entities - IPL maintains a Receivables Agreement whereby it may sell its customer accounts receivables, unbilled revenues and certain other accounts receivables to a third party through wholly-owned and consolidated special purpose entities. The purchase commitment from the third party to which IPL sells its receivables expires in March 2023. In 2021 and 2020, IPL evaluated the third party that purchases IPL’s receivable assets under the Receivables Agreement and believes that the third party is a VIE; however, IPL concluded consolidation of the third party was not required.

In addition, IPL’s sales of accounts receivable program agreement contains a cross-default provision that is triggered if IPL or Alliant Energy incurs an event of default on debt totaling $100 million or more. If an event of default under IPL’s sales of accounts receivable program agreement occurs, then the counterparty could terminate such agreement. Refer to Note 5(b) for additional information regarding IPL’s sales of accounts receivable program.

Guarantees and Indemnifications - At December 31, 2021, various guarantees and indemnifications are outstanding related to Alliant Energy’s cash equity ownership interest in a non-utility wind farm and prior divestiture activities. Refer to Note 17(d) for additional information.

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Certain Financial Commitments -

Contractual Obligations - Alliant Energy, IPL and WPL have various long-term contractual obligations as of December 31, 2021, which include long-term debt maturities in Note 9(b), operating and finance leases in Note 10, capital purchase obligations in Note 17(a), and other purchase obligations in Note 17(b). At December 31, 2021, Alliant Energy, IPL and WPL had no uncertain tax positions recorded as liabilities. Refer to Note 13(a) for anticipated pension and OPEB funding amounts. Refer to “Construction and Acquisition Expenditures” above for additional information on construction and acquisition programs. In addition, at December 31, 2021, there were various other liabilities included on the balance sheets that, due to the nature of the liabilities, the timing of payments cannot be estimated.

OTHER MATTERS

Market Risk Sensitive Instruments and Positions - Primary market risk exposures are associated with commodity prices, investment prices and interest rates. Risk management policies are used to monitor and assist in mitigating these market risks and derivative instruments are used to manage some of the exposures related to commodity prices. Refer to Notes 1(h) and 15 for further discussion of derivative instruments, and Note 1(g) for details of utility cost recovery mechanisms that significantly reduce commodity risk.

Commodity Price - Alliant Energy, IPL and WPL are exposed to the impact of market fluctuations in the price and transportation costs of commodities they procure and market. Established policies and procedures mitigate risks associated with these market fluctuations, including the use of various commodity derivatives and contracts of various durations for the forward sale and purchase of these commodities. Exposure to commodity price risks in the utility businesses is also significantly mitigated by current rate-making structures in place for recovery of fuel-related costs as well as the cost of natural gas purchased for resale. IPL’s electric and gas tariffs and WPL’s wholesale electric and gas tariffs provide for subsequent monthly adjustments to their tariff rates for material changes in prudently incurred commodity costs. IPL’s and WPL’s rate mechanisms, combined with commodity derivatives, significantly reduce commodity risk associated with their electric and gas margins. WPL’s retail electric margins have modest exposure to the impact of changes in commodity prices due largely to the current retail recovery mechanism in place in Wisconsin for fuel-related costs.

Investment Price - Alliant Energy, IPL and WPL are exposed to investment price risk as a result of their investments in securities, largely related to securities held by their pension and OPEB plans. Refer to Note 13(a) for details of the securities held by their pension and OPEB plans. Refer to “Critical Accounting Policies and Estimates” for the impact on retirement plan costs of changes in the rate of returns earned by plan assets.

Interest Rate - Alliant Energy, IPL and WPL are exposed to risk resulting from changes in interest rates associated with variable-rate borrowings. In addition, Alliant Energy and IPL are exposed to risk resulting from changes in interest rates on cash amounts outstanding under IPL’s sales of accounts receivable program. Assuming the impact of a hypothetical 100 basis point increase in interest rates on variable-rate borrowings and cash amounts outstanding under IPL’s sales of accounts receivable program at December 31, 2021, Alliant Energy’s, IPL’s and WPL’s annual pre-tax expense would increase by approximately $8 million, $0 and $2 million, respectively. Refer to Notes 5(b) and 9 for additional information on cash amounts outstanding under IPL’s sales of accounts receivable program, and short- and long-term variable-rate borrowings, respectively. Refer to “Critical Accounting Policies and Estimates” for the impacts of changes in discount rates on retirement plan obligations and costs.

Critical Accounting Policies and Estimates - Alliant Energy’s, IPL’s and WPL’s financial statements are prepared in conformity with GAAP, which requires management to apply accounting policies, judgments and assumptions, and make estimates that affect results of operations and the amounts of assets and liabilities reported in the financial statements. The following accounting policies and estimates are critical to the business and the understanding of financial results as they require critical assumptions and judgments by management. The results of these assumptions and judgments form the basis for making estimates regarding the results of operations and the amounts of assets and liabilities that are not readily apparent from other sources. Actual financial results may differ materially from estimates. Management has discussed these critical accounting policies and estimates with the Audit Committee of the Board of Directors. Refer to Note 1 for additional discussion of accounting policies and estimates used in the preparation of the financial statements.

Regulatory Assets and Regulatory Liabilities - IPL and WPL are regulated by various federal and state regulatory agencies. As a result, they are subject to GAAP for regulated operations, which recognizes that the actions of a regulator can provide reasonable assurance of the existence of an asset or liability. Regulatory assets or regulatory liabilities arise as a result of a difference between GAAP and actions imposed by the regulatory agencies in the rate-making process. Regulatory assets generally represent incurred costs that have been deferred as such costs are probable of recovery in future customer rates. Regulatory liabilities generally represent obligations to make refunds to customers or amounts collected in rates for which the related costs have not yet been incurred. Regulatory assets and regulatory liabilities are recognized in accordance with the rulings of applicable federal and state regulators, and future regulatory rulings may impact the carrying value and accounting treatment of regulatory assets and regulatory liabilities.

Assumptions and judgments are made each reporting period regarding whether regulatory assets are probable of future recovery and regulatory liabilities are probable future obligations by considering factors such as regulatory environment

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changes, rate orders issued by the applicable regulatory agencies, historical decisions by such regulatory agencies regarding similar regulatory assets and regulatory liabilities, and subsequent events of such regulatory agencies. The decisions made by regulatory authorities have an impact on the recovery of costs, the rate of return on invested capital and the timing and amount of assets to be recovered by rates. A change in these decisions may result in a material impact on results of operations and the amount of assets and liabilities in the financial statements. Note 2 provides details of the nature and amounts of regulatory assets and regulatory liabilities assessed at December 31, 2021.

Income Taxes - Alliant Energy, IPL and WPL are subject to income taxes in various jurisdictions. Assumptions and judgments are made each reporting period to estimate income tax assets, liabilities, benefits and expenses. Judgments and assumptions are supported by historical data and reasonable projections. Significant changes in these judgments and assumptions could have a material impact on financial condition and results of operations. Alliant Energy’s and IPL’s critical assumptions and judgments for 2021 include estimates of qualifying deductions for repairs expenditures and allocation of mixed service costs due to the impact of Iowa rate-making principles on such property-related differences. Critical assumptions and judgments also include projections of future taxable income used to determine the ability to utilize net operating losses and credit carryforwards prior to their expiration. Refer to Note 12 for further discussion of tax matters.

Effect of Rate-making on Property-related Differences - Alliant Energy’s and IPL’s effective income tax rates are normally impacted by certain property-related differences at IPL for which deferred tax is not recorded in the income statement pursuant to Iowa rate-making principles. Changes in methods or assumptions regarding the amount of IPL’s qualifying repairs expenditures, allocation of mixed service costs, and costs related to retirement or removal of depreciable property could result in a material impact on Alliant Energy’s and IPL’s financial condition and results of operations.

Carryforward Utilization - Significant federal tax credit carryforwards and federal and state net operating loss carryforwards exist for Alliant Energy, IPL and WPL as of December 31, 2021. Based on projections of current and future taxable income, Alliant Energy, IPL and WPL plan to utilize substantially all of these carryforwards prior to their expiration. Taxable income must be reduced by federal net operating losses carryforwards prior to utilizing federal tax credit carryforwards. Alliant Energy does not expect to utilize all of its federal net operating loss carryforwards until 2023, and therefore, currently does not expect to utilize 2002 vintage federal credit carryforwards prior to their expiration in 2022, resulting in valuation allowances that remain as of December 31, 2021. Federal credit carryforwards generated from 2003 through 2008, which amount to $12 million for Alliant Energy, are expected to be utilized within five years of expiration. All other federal credit carryforwards and federal net operating loss carryforwards are expected to be utilized more than five years before expiration. Changes in tax regulations or assumptions regarding current and future taxable income could require changes to valuation allowances in the future resulting in a material impact on financial condition and results of operations.

Long-Lived Assets - Periodic assessments regarding the recoverability of certain long-lived assets are completed when factors indicate the carrying value of such assets may not be recoverable or such assets are planned to be sold. These assessments require significant assumptions and judgments by management. The long-lived assets assessed for impairment generally include certain assets within regulated operations that may not be fully recovered from IPL’s and WPL’s customers as a result of regulatory decisions in the future, and assets within non-utility operations that are proposed to be sold or are currently generating operating losses.

Regulated Operations - Alliant Energy’s, IPL’s and WPL’s long-lived assets within their regulated operations that were assessed for impairment and plant abandonment in 2021 included IPL’s and WPL’s generating units subject to early retirement.

Generating Units Subject to Early Retirement - Alliant Energy, IPL and WPL evaluate future plans for their electric generation fleet and have announced the early retirement of certain older and less-efficient EGUs. When it becomes probable that an EGU will be retired before the end of its useful life, Alliant Energy, IPL and WPL must assess whether the EGU meets the criteria to be considered probable of abandonment. EGUs that are considered probable of abandonment generally have material remaining net book values and are expected to cease operations in the near term significantly before the end of their original estimated useful lives. If an EGU meets such criteria to be considered probable of abandonment, Alliant Energy, IPL and WPL must assess the probability of full recovery of the remaining carrying value of such EGU. If it is probable that regulators will not allow full recovery of and a full return on the remaining net book value of the abandoned EGU, an impairment charge is recognized equal to the difference between the remaining carrying value and the present value of the future revenues expected from the abandoned EGU.

Alliant Energy and IPL concluded that Lansing, and Alliant Energy and WPL concluded that Edgewater Unit 5 and Columbia Units 1 and 2, met the criteria to be considered probable of abandonment as of December 31, 2021. IPL and WPL are currently allowed a full recovery of and a full return on its respective EGUs from both its retail and wholesale customers, and as a result, Alliant Energy, IPL and WPL concluded that no impairment was required as of December 31, 2021. Alliant Energy, IPL and WPL evaluated their other EGUs that are subject to early retirement and determined that no other EGUs met the criteria to be considered probable of abandonment as of December 31, 2021. Note 3 provides additional details of these assets anticipated to be retired early.

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Unbilled Revenues - Unbilled revenues are primarily associated with utility operations. Energy sales to individual customers are based on the reading of customers’ meters, which occurs on a systematic basis throughout the month. Amounts of energy delivered to customers since the date of the last meter reading are estimated at the end of each reporting period and the corresponding estimated unbilled revenue is recorded. The unbilled revenue is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates. Such process involves the use of various judgments and assumptions and significant changes in these judgments and assumptions could have a material impact on results of operations. As of December 31, 2021, unbilled revenues related to Alliant Energy’s utility operations were $195 million ($104 million at IPL and $91 million at WPL).

Pensions and Other Postretirement Benefits - Alliant Energy, IPL and WPL sponsor various defined benefit pension and OPEB plans that provide benefits to a significant portion of their employees and retirees. Assumptions and judgments are made periodically to estimate the obligations and costs related to their retirement plans. There are many judgments and assumptions involved in determining an entity’s pension and other postretirement liabilities and costs each period including employee demographics (including life expectancies and compensation levels), discount rates, assumed rates of return and funding. Changes made to plan provisions may also impact current and future benefits costs. Judgments and assumptions are supported by historical data and reasonable projections and are reviewed at least annually. The following table shows the impacts of changing certain key actuarial assumptions discussed above (in millions):

	Defined Benefit Pension Plans		OPEB Plans
Change in Actuarial Assumption	Impact on Projected Benefit Obligation at December 31, 2021	Impact on 2022 Net Periodic Benefit Costs	Impact on Accumulated Benefit Obligation at December 31, 2021	Impact on 2022 Net Periodic Benefit Costs
Alliant Energy
1% change in discount rate	$161	$11	$20	$2
1% change in expected rate of return	N/A	10	N/A	1
IPL
1% change in discount rate	75	6	7	1
1% change in expected rate of return	N/A	4	N/A	1
WPL
1% change in discount rate	71	6	7	1
1% change in expected rate of return	N/A	4	N/A	—

Contingencies - Assumptions and judgments are made each reporting period regarding the future outcome of contingent events. Loss contingency amounts are recorded for any contingent events for which the likelihood of loss is probable and able to be reasonably estimated based upon current available information. The amounts recorded may differ from actuals when the uncertainty is resolved. The estimates made in accounting for contingencies, and the gains and losses that are recorded upon the ultimate resolution of these uncertainties, could have a significant effect on results of operations and the amount of assets and liabilities in the financial statements.

Effective January 1, 2020 upon the adoption of the new accounting standard for credit losses, certain contingencies, such as Alliant Energy Resources, LLC’s guarantees of the partnership obligations of an affiliate of Whiting Petroleum, require estimation each reporting period of the expected credit losses on those contingencies. These estimates require significant judgment and result in recognition of a credit loss liability sooner than the previous accounting standards, which required recognition when the contingency became probable and could be reasonably estimated based on then currently available information. With respect to Alliant Energy’s guarantees of the partnership obligations of an affiliate of Whiting Petroleum, the most significant judgments in determining the credit loss liability were the estimate of the exposure under the guarantees and the methodology used for calculating the credit loss liability. As of December 31, 2021, Alliant Energy currently estimates the exposure to be a portion of the known partnership abandonment obligations. The methodology used to determine the credit loss liability considers both quantitative and qualitative information, which utilizes potential outcomes in a range of possible estimated amounts. Factors considered include market and external data points, the creditworthiness of the other partners, Whiting Petroleum’s emergence from bankruptcy in the third quarter of 2020, and forecasted cash flow expenditures associated with the abandonment obligations based on information made available to Alliant Energy. Note 1(l) provides discussion of the adoption of the new accounting standard for credit losses.

Note 17 provides further discussion of contingencies assessed at December 31, 2021 that may have a material impact on financial condition and results of operations, including various pending legal proceedings, guarantees and indemnifications.

ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

Quantitative and Qualitative Disclosures About Market Risk are reported in “Other Matters - Market Risk Sensitive Instruments and Positions” in MDA.

ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

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REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Shareowners and the Board of Directors of Alliant Energy Corporation:

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Alliant Energy Corporation and subsidiaries (the “Company”) as of December 31, 2021 and 2020, the related consolidated statements of income, equity, and cash flows, for each of the three years in the period ended December 31, 2021, and the related notes and the schedules listed in the Index at Item 15 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2021 and 2020, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2021, in conformity with accounting principles generally accepted in the United States of America.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company’s internal control over financial reporting as of December 31, 2021, based on criteria established in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission and our report dated February 18, 2022, expressed an unqualified opinion on the Company’s internal control over financial reporting.

Basis for Opinion

These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current-period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Regulatory Assets and Regulatory Liabilities - Impact of rate regulation on the financial statements - Refer to Notes 1 and 2 to the financial statements

Critical Audit Matter Description

Alliant Energy Corporation, through its wholly-owned subsidiaries Interstate Power and Light Company and Wisconsin Power and Light Company, is subject to rate regulation by the Federal Energy Regulatory Commission and the respective state commissions in Iowa and Wisconsin (collectively the “regulatory agencies”). Management has determined it meets the requirements under accounting principles generally accepted in the United States of America to prepare its financial statements applying the Regulated Operations Topic 980 of the Financial Accounting Standards Board’s Accounting Standards Codification. As of December 31, 2021, the Company had a recorded consolidated regulatory assets balance of $1,940 million and regulatory liabilities balance of $1,271 million.

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The Company’s rates are subject to regulatory rate-setting processes and periodic earnings oversight. The regulation of rates is premised on the full recovery of prudently incurred costs and a reasonable rate of return on invested capital. Regulatory assets represent incurred costs that have been deferred and are probable of recovery in future customer rates. Regulatory liabilities represent obligations to make refunds to customers or amounts collected in rates for which the costs have not yet been incurred. The Company’s regulatory assets and regulatory liabilities are recognized in accordance with the rulings of the regulatory agencies. A change in these rulings may result in a material impact on results of operations and the amount of assets and liabilities in the financial statements. Future regulatory rulings may impact the carrying value and accounting treatment of the regulatory assets and regulatory liabilities.

We identified the impact of rate regulation as a critical audit matter due to the significant judgments made by management to support its assertions about impacted account balances and disclosures and the high degree of subjectivity involved in assessing the impact of future regulatory orders on the financial statements. Management judgments include assessing the likelihood of the recovery of incurred costs and refund of obligations to customers in future rates. Given that management’s accounting judgments are based on assumptions about the outcome of future decisions by the regulatory agencies, auditing these judgments required specialized knowledge of accounting for rate regulation and the rate-setting process due to its inherent complexities.

How the Critical Audit Matter Was Addressed in the Audit

Our audit procedures related to the regulatory filings by management and the uncertainty of future decisions by the regulatory agencies included the following, among others:

•We tested the design and operating effectiveness of management’s controls over the evaluation of regulatory assets and liabilities, including the monitoring and evaluation of regulatory developments that may affect the likelihood of recovering costs in future rates or of a future reduction in rates.

•We obtained and evaluated the Company’s analysis supporting the probability of recovery for regulatory assets or refund or future reduction in rates for regulatory liabilities not yet addressed in a regulatory order to assess the reasonability of management’s assertions.

•We inquired of management regarding current events impacting the Company and inspected minutes of the board of directors and other committees of the Company and evaluated whether matters were identified that may have an impact on recorded regulatory asset and liability balances.

•We read relevant regulatory orders, regulatory statutes, interpretations, procedural memorandums, filings made by interveners, and other publicly available information issued by the regulatory agencies that pertain to the Company as well as to other relevant public utilities. We evaluated the external information and assessed whether there were matters in such information that would be contradictory to the assessment of recovery of the Company’s regulatory assets or refund of regulatory liabilities.

•We inquired of management about property, plant, and equipment, net that may be abandoned. We inspected minutes of the board of directors and other committees of the Company, regulatory orders and other filings with the regulatory agencies to identify evidence that may contradict management’s assertion regarding probability of an abandonment or that may have an impact on the recorded balances.

•We evaluated the Company’s disclosures related to the impacts of rate regulation and regulatory developments, including disclosures related to the regulatory balances recorded.

/s/ DELOITTE & TOUCHE LLP

Milwaukee, Wisconsin

February 18, 2022

We have served as the Company’s auditor since 2002.

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ALLIANT ENERGY CORPORATION

CONSOLIDATED STATEMENTS OF INCOME

	Year Ended December 31,
	2021	2020	2019
	(in millions, except per share amounts)
Revenues:
Electric utility	$3,081	$2,920	$3,064
Gas utility	456	373	455
Other utility	49	49	46
Non-utility	83	74	83
Total revenues	3,669	3,416	3,648
Operating expenses:
Electric production fuel and purchased power	642	652	777
Electric transmission service	537	449	481
Cost of gas sold	258	182	222
Other operation and maintenance	676	670	712
Depreciation and amortization	657	615	567
Taxes other than income taxes	104	108	111
Total operating expenses	2,874	2,676	2,870
Operating income	795	740	778
Other (income) and deductions:
Interest expense	277	275	273
Equity income from unconsolidated investments, net	(62)	(61)	(53)
Allowance for funds used during construction	(25)	(55)	(93)
Other	5	14	15
Total other (income) and deductions	195	173	142
Income before income taxes	600	567	636
Income tax expense (benefit)	(74)	(57)	69
Net income	674	624	567
Preferred dividend requirements of Interstate Power and Light Company	15	10	10
Net income attributable to Alliant Energy common shareowners	$659	$614	$557
Weighted average number of common shares outstanding:
Basic	250.2	248.4	238.5
Diluted	250.7	248.7	239.0
Earnings per weighted average common share attributable to Alliant Energy common shareowners:
Basic	$2.63	$2.47	$2.34
Diluted	$2.63	$2.47	$2.33

Refer to accompanying Combined Notes to Consolidated Financial Statements.

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ALLIANT ENERGY CORPORATION

CONSOLIDATED BALANCE SHEETS

	December 31,
	2021	2020
	(in millions, except per share and share amounts)
ASSETS
Current assets:
Cash and cash equivalents	$39	$54
Accounts receivable, less allowance for expected credit losses	440	412
Production fuel, at weighted average cost	51	66
Gas stored underground, at weighted average cost	82	46
Materials and supplies, at weighted average cost	113	105
Regulatory assets	104	81
Other	240	123
Total current assets	1,069	887
Property, plant and equipment, net	14,987	14,336
Investments:
ATC Holdings	338	331
Other	179	154
Total investments	517	485
Other assets:
Regulatory assets	1,836	1,929
Deferred charges and other	144	73
Total other assets	1,980	2,002
Total assets	$18,553	$17,710

LIABILITIES AND EQUITY
Current liabilities:
Current maturities of long-term debt	$633	$8
Commercial paper	515	389
Accounts payable	436	377
Accrued taxes	58	67
Regulatory liabilities	186	249
Other	226	207
Total current liabilities	2,054	1,297
Long-term debt, net (excluding current portion)	6,735	6,769
Other liabilities:
Deferred tax liabilities	1,927	1,814
Regulatory liabilities	1,085	1,057
Pension and other benefit obligations	374	511
Other	388	374
Total other liabilities	3,774	3,756
Commitments and contingencies (Note 17)
Equity:
Alliant Energy Corporation common equity:
Common stock - $0.01 par value - 480,000,000 shares authorized; 250,474,529 and 249,868,415 shares outstanding	3	2
Additional paid-in capital	2,749	2,704
Retained earnings	3,250	2,994
Accumulated other comprehensive loss	—	(1)
Shares in deferred compensation trust - 383,532 and 380,542 shares at a weighted average cost of $30.59 and $28.73 per share	(12)	(11)
Total Alliant Energy Corporation common equity	5,990	5,688
Cumulative preferred stock of Interstate Power and Light Company	—	200
Total equity	5,990	5,888
Total liabilities and equity	$18,553	$17,710

Refer to accompanying Combined Notes to Consolidated Financial Statements.

44

ALLIANT ENERGY CORPORATION

CONSOLIDATED STATEMENTS OF CASH FLOWS

	Year Ended December 31,
	2021	2020	2019
	(in millions)
Cash flows from operating activities:
Net income	$674	$624	$567
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	657	615	567
Deferred tax expense (benefit) and tax credits	(78)	(66)	56
Equity component of allowance for funds used during construction	(18)	(39)	(66)
Other	35	37	20
Other changes in assets and liabilities:
Accounts receivable	(530)	(468)	(472)
Derivative assets	(142)	(7)	2
Regulatory assets	51	(130)	(16)
Regulatory liabilities	(66)	(113)	(40)
Deferred income taxes	193	171	54
Pension and other benefit obligations	(137)	27	(25)
DAEC PPA amendment buyout payment	—	(110)	—
Other	(57)	(40)	13
Net cash flows from operating activities	582	501	660
Cash flows used for investing activities:
Construction and acquisition expenditures:
Utility business	(1,070)	(1,293)	(1,539)
Other	(99)	(73)	(101)
Cash receipts on sold receivables	502	458	413
Other	(61)	(43)	(60)
Net cash flows used for investing activities	(728)	(951)	(1,287)
Cash flows from financing activities:
Common stock dividends	(403)	(377)	(337)
Proceeds from issuance of common stock, net	28	247	390
Payments to redeem cumulative preferred stock of IPL	(200)	—	—
Proceeds from issuance of long-term debt	600	1,250	950
Payments to retire long-term debt	(8)	(657)	(256)
Net change in commercial paper	126	52	(104)
Other	(13)	(27)	(24)
Net cash flows from financing activities	130	488	619
Net increase (decrease) in cash, cash equivalents and restricted cash	(16)	38	(8)
Cash, cash equivalents and restricted cash at beginning of period	56	18	26
Cash, cash equivalents and restricted cash at end of period	$40	$56	$18
Supplemental cash flows information:
Cash (paid) refunded during the period for:
Interest	($272)	($274)	($268)
Income taxes, net	($3)	$5	$21
Significant non-cash investing and financing activities:
Accrued capital expenditures	$141	$131	$196
Beneficial interest obtained in exchange for securitized accounts receivable	$214	$188	$188

Refer to accompanying Combined Notes to Consolidated Financial Statements.

45

ALLIANT ENERGY CORPORATION

CONSOLIDATED STATEMENTS OF EQUITY

	Total Alliant Energy Common Equity
				Accumulated	Shares in	Cumulative
		Additional		Other	Deferred	Preferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Stock	Total
	Stock	Capital	Earnings	Income (Loss)	Trust	of IPL	Equity
	(in millions)
2019:
Beginning balance	$2	$2,046	$2,546	$2	($10)	$200	$4,786
Net income attributable to Alliant Energy common shareowners			557				557
Common stock dividends ($1.42 per share)			(337)				(337)
Equity forward settlements and Shareowner Direct Plan issuances		390					390
Equity-based compensation plans and other		10					10
Other comprehensive loss, net of tax				(1)			(1)
Ending balance	2	2,446	2,766	1	(10)	200	5,405
2020:
Net income attributable to Alliant Energy common shareowners			614				614
Common stock dividends ($1.52 per share)			(377)				(377)
Equity forward settlements and Shareowner Direct Plan issuances		247					247
Equity-based compensation plans and other		11			(1)		10
Adoption of new accounting standard, net of tax (refer to Note 1(l))			(9)				(9)
Other comprehensive loss, net of tax				(2)			(2)
Ending balance	2	2,704	2,994	(1)	(11)	200	5,888
2021:
Net income attributable to Alliant Energy common shareowners			659				659
Common stock dividends ($1.61 per share)			(403)				(403)
Shareowner Direct Plan issuances	1	27					28
Equity-based compensation plans and other		18			(1)		17
Redemption of IPL’s cumulative preferred stock						(200)	(200)
Other comprehensive income, net of tax				1			1
Ending balance	$3	$2,749	$3,250	$—	($12)	$—	$5,990

Refer to accompanying Combined Notes to Consolidated Financial Statements.

46

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Shareowner and the Board of Directors of Interstate Power and Light Company:

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Interstate Power and Light Company and subsidiaries (the “Company”) as of December 31, 2021 and 2020, the related consolidated statements of income, equity, and cash flows, for each of the three years in the period ended December 31, 2021, and the related notes and the schedule listed in the Index at Item 15 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2021 and 2020, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2021, in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits, we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company’s internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current-period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Regulatory Assets and Regulatory Liabilities - Impact of rate regulation on the financial statements - Refer to Notes 1 and 2 to the financial statements

Critical Audit Matter Description

Interstate Power and Light Company is subject to rate regulation by the Federal Energy Regulatory Commission and state commission in Iowa (collectively the “regulatory agencies”). Management has determined it meets the requirements under accounting principles generally accepted in the United States of America to prepare its financial statements applying the Regulated Operations Topic 980 of the Financial Accounting Standards Board’s Accounting Standards Codification. As of December 31, 2021, the Company had a recorded consolidated regulatory assets balance of $1,443 million and regulatory liabilities balance of $691 million.

The Company’s rates are subject to regulatory rate-setting processes and periodic earnings oversight. The regulation of rates is premised on the full recovery of prudently incurred costs and a reasonable rate of return on invested capital. Regulatory assets represent incurred costs that have been deferred and are probable of recovery in future customer rates. Regulatory liabilities represent obligations to make refunds to customers or amounts collected in rates for which the costs have not yet been incurred. The Company’s regulatory assets and regulatory liabilities are recognized in accordance with the rulings of the regulatory agencies. A change in these rulings may result in a material impact on results of operations and the amount of assets and liabilities in the financial statements. Future regulatory rulings may impact the carrying value and accounting treatment of the regulatory assets and regulatory liabilities.

47

We identified the impact of rate regulation as a critical audit matter due to the significant judgments made by management to support its assertions about impacted account balances and disclosures and the high degree of subjectivity involved in assessing the impact of future regulatory orders on the financial statements. Management judgments include assessing the likelihood of the recovery of incurred costs and refund of obligations to customers in future rates. Given that management’s accounting judgments are based on assumptions about the outcome of future decisions by the regulatory agencies, auditing these judgments required specialized knowledge of accounting for rate regulation and the rate-setting process due to its inherent complexities.

How the Critical Audit Matter Was Addressed in the Audit

Our audit procedures related to the regulatory filings by management and the uncertainty of future decisions by the regulatory agencies included the following, among others:

•We tested the design and operating effectiveness of management’s controls over the evaluation of regulatory assets and liabilities, including the monitoring and evaluation of regulatory developments that may affect the likelihood of recovering costs in future rates or of a future reduction in rates.

•We obtained and evaluated the Company’s analysis supporting the probability of recovery for regulatory assets or refund or future reduction in rates for regulatory liabilities not yet addressed in a regulatory order to assess the reasonability of management’s assertions.

•We inquired of management regarding current events impacting the Company and inspected minutes of the board of directors and other committees of the Company and evaluated whether matters were identified that may have an impact on recorded regulatory asset and liability balances.

•We read relevant regulatory orders, regulatory statutes, interpretations, procedural memorandums, filings made by interveners, and other publicly available information issued by the regulatory agencies that pertain to the Company as well as to other relevant public utilities. We evaluated the external information and assessed whether there were matters in such information that would be contradictory to the assessment of recovery of the Company’s regulatory assets or refund of regulatory liabilities.

•We inquired of management about property, plant, and equipment, net that may be abandoned. We inspected minutes of the board of directors and other committees of the Company, regulatory orders, and other filings with the regulatory agencies to identify evidence that may contradict management’s assertion regarding probability of an abandonment or that may have an impact on the recorded balances.

•We evaluated the Company’s disclosures related to the impacts of rate regulation and regulatory developments, including disclosures related to the regulatory balances recorded.

/s/ DELOITTE & TOUCHE LLP

Milwaukee, Wisconsin

February 18, 2022

We have served as the Company’s auditor since 2002.

48

INTERSTATE POWER AND LIGHT COMPANY

CONSOLIDATED STATEMENTS OF INCOME

	Year Ended December 31,
	2021	2020	2019
	(in millions)
Revenues:
Electric utility	$1,752	$1,695	$1,781
Gas utility	265	208	264
Steam and other	46	44	44
Total revenues	2,063	1,947	2,089
Operating expenses:
Electric production fuel and purchased power	295	352	435
Electric transmission service	367	298	340
Cost of gas sold	149	99	120
Other operation and maintenance	362	375	404
Depreciation and amortization	375	356	327
Taxes other than income taxes	55	57	60
Total operating expenses	1,603	1,537	1,686
Operating income	460	410	403
Other (income) and deductions:
Interest expense	139	139	127
Allowance for funds used during construction	(9)	(24)	(50)
Other	1	8	8
Total other (income) and deductions	131	123	85
Income before income taxes	329	287	318
Income tax expense (benefit)	(36)	(47)	24
Net income	365	334	294
Preferred dividend requirements	15	10	10
Net income available for common stock	$350	$324	$284

Earnings per share data is not disclosed given Alliant Energy Corporation is the sole shareowner of all shares of IPL’s common stock outstanding during the periods presented.

Refer to accompanying Combined Notes to Consolidated Financial Statements.

49

INTERSTATE POWER AND LIGHT COMPANY

CONSOLIDATED BALANCE SHEETS

	December 31,
	2021	2020
	(in millions, except per share and share amounts)
ASSETS
Current assets:
Cash and cash equivalents	$34	$50
Accounts receivable, less allowance for expected credit losses	241	210
Income tax refunds receivable	8	26
Production fuel, at weighted average cost	29	48
Gas stored underground, at weighted average cost	40	20
Materials and supplies, at weighted average cost	70	63
Regulatory assets	73	52
Other	69	27
Total current assets	564	496
Property, plant and equipment, net	7,983	7,889
Other assets:
Regulatory assets	1,370	1,431
Deferred charges and other	79	33
Total other assets	1,449	1,464
Total assets	$9,996	$9,849

LIABILITIES AND EQUITY
Current liabilities:
Accounts payable	$173	$162
Accounts payable to associated companies	39	45
Regulatory liabilities	84	103
Accrued taxes	56	54
Accrued interest	36	34
Other	67	49
Total current liabilities	455	447
Long-term debt, net	3,643	3,345
Other liabilities:
Deferred tax liabilities	1,083	1,035
Regulatory liabilities	607	573
Pension and other benefit obligations	127	186
Other	312	299
Total other liabilities	2,129	2,093
Commitments and contingencies (Note 17)
Equity:
Interstate Power and Light Company common equity:
Common stock - $2.50 par value - 24,000,000 shares authorized; 13,370,788 shares outstanding	33	33
Additional paid-in capital	2,807	2,752
Retained earnings	929	979
Total Interstate Power and Light Company common equity	3,769	3,764
Cumulative preferred stock	—	200
Total equity	3,769	3,964
Total liabilities and equity	$9,996	$9,849

Refer to accompanying Combined Notes to Consolidated Financial Statements.

50

INTERSTATE POWER AND LIGHT COMPANY

CONSOLIDATED STATEMENTS OF CASH FLOWS

	Year Ended December 31,
	2021	2020	2019
	(in millions)
Cash flows from (used for) operating activities:
Net income	$365	$334	$294
Adjustments to reconcile net income to net cash flows from (used for) operating activities:
Depreciation and amortization	375	356	327
Deferred tax expense (benefit) and tax credits	(14)	(52)	15
Equity component of allowance for funds used during construction	(7)	(17)	(35)
Other	11	12	1
Other changes in assets and liabilities:
Accounts receivable	(539)	(466)	(467)
Derivative assets	(55)	(7)	(5)
Regulatory assets	30	(93)	(11)
Accounts payable	15	6	(21)
Regulatory liabilities	1	(20)	2
Deferred income taxes	62	79	35
Pension and other benefit obligations	(59)	18	(11)
DAEC PPA amendment buyout payment	—	(110)	—
Other	(32)	(46)	49
Net cash flows from (used for) operating activities	153	(6)	173
Cash flows from (used for) investing activities:
Construction and acquisition expenditures	(384)	(687)	(1,020)
Cash receipts on sold receivables	502	458	413
Other	(27)	(72)	(60)
Net cash flows from (used for) investing activities	91	(301)	(667)
Cash flows from (used for) financing activities:
Common stock dividends	(400)	(236)	(168)
Capital contributions from parent	50	404	125
Payments to redeem cumulative preferred stock	(200)	—	—
Proceeds from issuance of long-term debt	300	400	600
Payments to retire long-term debt	—	(200)	—
Net change in commercial paper	—	—	(50)
Other	(10)	(20)	(16)
Net cash flows from (used for) financing activities	(260)	348	491
Net increase (decrease) in cash, cash equivalents and restricted cash	(16)	41	(3)
Cash, cash equivalents and restricted cash at beginning of period	50	9	12
Cash, cash equivalents and restricted cash at end of period	$34	$50	$9
Supplemental cash flows information:
Cash (paid) refunded during the period for:
Interest	($138)	($141)	($122)
Income taxes, net	$47	($18)	$7
Significant non-cash investing and financing activities:
Accrued capital expenditures	$57	$73	$112
Beneficial interest obtained in exchange for securitized accounts receivable	$214	$188	$188

Refer to accompanying Combined Notes to Consolidated Financial Statements.

51

INTERSTATE POWER AND LIGHT COMPANY

CONSOLIDATED STATEMENTS OF EQUITY

	Total IPL Common Equity
		Additional		Cumulative
	Common	Paid-In	Retained	Preferred	Total
	Stock	Capital	Earnings	Stock	Equity
	(in millions)
2019:
Beginning balance	$33	$2,223	$775	$200	$3,231
Net income available for common stock			284		284
Common stock dividends			(168)		(168)
Capital contributions from parent		125			125
Ending balance	33	2,348	891	200	3,472
2020:
Net income available for common stock			324		324
Common stock dividends			(236)		(236)
Capital contributions from parent		404			404
Ending balance	33	2,752	979	200	3,964
2021:
Net income available for common stock			350		350
Common stock dividends			(400)		(400)
Capital contributions from parent		50			50
Redemption of cumulative preferred stock				(200)	(200)
Other		5			5
Ending balance	$33	$2,807	$929	$—	$3,769

Refer to accompanying Combined Notes to Consolidated Financial Statements.

52

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Shareowner and the Board of Directors of Wisconsin Power and Light Company:

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Wisconsin Power and Light Company and subsidiary (the “Company”) as of December 31, 2021 and 2020, the related consolidated statements of income, equity, and cash flows, for each of the three years in the period ended December 31, 2021, and the related notes and the schedule listed in the Index at Item 15 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2021 and 2020, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2021, in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits, we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company’s internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current-period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Regulatory Assets and Regulatory Liabilities - Impact of rate regulation on the financial statements - Refer to Notes 1 and 2 to the financial statements

Critical Audit Matter Description

Wisconsin Power and Light Company is subject to rate regulation by the Federal Energy Regulatory Commission and state commission in Wisconsin (collectively the “regulatory agencies”). Management has determined it meets the requirements under accounting principles generally accepted in the United States of America to prepare its financial statements applying the Regulated Operations Topic 980 of the Financial Accounting Standards Board’s Accounting Standards Codification. As of December 31, 2021, the Company had a recorded consolidated regulatory assets balance of $497 million and regulatory liabilities balance of $580 million.

The Company’s rates are subject to regulatory rate-setting processes and periodic earnings oversight. The regulation of rates is premised on the full recovery of prudently incurred costs and a reasonable rate of return on invested capital. Regulatory assets represent incurred costs that have been deferred and are probable of recovery in future customer rates. Regulatory liabilities represent obligations to make refunds to customers or amounts collected in rates for which the costs have not yet been incurred. The Company’s regulatory assets and regulatory liabilities are recognized in accordance with the rulings of the regulatory agencies. A change in these rulings may result in a material impact on results of operations and the amount of assets and liabilities in the financial statements. Future regulatory rulings may impact the carrying value and accounting treatment of the regulatory assets and regulatory liabilities.

53

We identified the impact of rate regulation as a critical audit matter due to the significant judgments made by management to support its assertions about impacted account balances and disclosures and the high degree of subjectivity involved in assessing the impact of future regulatory orders on the financial statements. Management judgments include assessing the likelihood of the recovery of incurred costs and refund of obligations to customers in future rates. Given that management’s accounting judgments are based on assumptions about the outcome of future decisions by the regulatory agencies, auditing these judgments required specialized knowledge of accounting for rate regulation and the rate-setting process due to its inherent complexities.

How the Critical Audit Matter Was Addressed in the Audit

Our audit procedures related to the regulatory filings by management and the uncertainty of future decisions by the regulatory agencies included the following, among others:

•We tested the design and operating effectiveness of management’s controls over the evaluation of regulatory assets and liabilities, including the monitoring and evaluation of regulatory developments that may affect the likelihood of recovering costs in future rates or of a future reduction in rates.

•We obtained and evaluated the Company’s analysis supporting the probability of recovery for regulatory assets or refund or future reduction in rates for regulatory liabilities not yet addressed in a regulatory order to assess the reasonability of management’s assertions.

•We inquired of management regarding current events impacting the Company and inspected minutes of the board of directors and other committees of the Company and evaluated whether matters were identified that may have an impact on recorded regulatory asset and liability balances.

•We read relevant regulatory orders, regulatory statutes, interpretations, procedural memorandums, filings made by interveners, and other publicly available information issued by the regulatory agencies that pertain to the Company as well as to other relevant public utilities. We evaluated the external information and assessed whether there were matters in such information that would be contradictory to the assessment of recovery of the Company’s regulatory assets or refund of regulatory liabilities.

•We inquired of management about property, plant, and equipment, net that may be abandoned. We inspected minutes of the board of directors and other committees of the Company, regulatory orders, and other filings with the regulatory agencies to identify evidence that may contradict management’s assertion regarding probability of an abandonment or that may have an impact on the recorded balances.

•We evaluated the Company’s disclosures related to the impacts of rate regulation and regulatory developments, including disclosures related to the regulatory balances recorded.

/s/ DELOITTE & TOUCHE LLP

Milwaukee, Wisconsin

February 18, 2022

We have served as the Company’s auditor since 2002.

54

WISCONSIN POWER AND LIGHT COMPANY

CONSOLIDATED STATEMENTS OF INCOME

	Year Ended December 31,
	2021	2020	2019
	(in millions)
Revenues:
Electric utility	$1,329	$1,225	$1,283
Gas utility	191	165	191
Other	3	5	2
Total revenues	1,523	1,395	1,476
Operating expenses:
Electric production fuel and purchased power	347	300	342
Electric transmission service	170	151	141
Cost of gas sold	109	83	102
Other operation and maintenance	268	254	261
Depreciation and amortization	276	254	236
Taxes other than income taxes	45	47	47
Total operating expenses	1,215	1,089	1,129
Operating income	308	306	347
Other (income) and deductions:
Interest expense	105	104	102
Allowance for funds used during construction	(16)	(31)	(43)
Other	2	3	6
Total other (income) and deductions	91	76	65
Income before income taxes	217	230	282
Income tax expense (benefit)	(51)	(19)	49
Net income	$268	$249	$233

Earnings per share data is not disclosed given Alliant Energy Corporation is the sole shareowner of all shares of WPL’s common stock outstanding during the periods presented.

Refer to accompanying Combined Notes to Consolidated Financial Statements.

55

WISCONSIN POWER AND LIGHT COMPANY

CONSOLIDATED BALANCE SHEETS

	December 31,
	2021	2020
	(in millions, except per share and share amounts)
ASSETS
Current assets:
Cash and cash equivalents	$2	$3
Accounts receivable, less allowance for expected credit losses	188	192
Production fuel, at weighted average cost	23	18
Gas stored underground, at weighted average cost	42	26
Materials and supplies, at weighted average cost	41	40
Regulatory assets	31	29
Prepaid gross receipts tax	40	42
Other	86	12
Total current assets	453	362
Property, plant and equipment, net	6,538	6,022
Other assets:
Regulatory assets	466	498
Deferred charges and other	61	30
Total other assets	527	528
Total assets	$7,518	$6,912

LIABILITIES AND EQUITY
Current liabilities:
Current maturities of long-term debt	$250	$—
Commercial paper	236	257
Accounts payable	190	154
Accounts payable to associated companies	39	35
Regulatory liabilities	102	146
Other	73	82
Total current liabilities	890	674
Long-term debt, net (excluding current portion)	2,179	2,130
Other liabilities:
Deferred tax liabilities	753	702
Regulatory liabilities	478	484
Pension and other benefit obligations	159	222
Other	236	222
Total other liabilities	1,626	1,630
Commitments and contingencies (Note 17)
Equity:
Wisconsin Power and Light Company common equity:
Common stock - $5 par value - 18,000,000 shares authorized; 13,236,601 shares outstanding	66	66
Additional paid-in capital	1,704	1,459
Retained earnings	1,053	953
Total Wisconsin Power and Light Company common equity	2,823	2,478
Total liabilities and equity	$7,518	$6,912

Refer to accompanying Combined Notes to Consolidated Financial Statements.

56

WISCONSIN POWER AND LIGHT COMPANY

CONSOLIDATED STATEMENTS OF CASH FLOWS

	Year Ended December 31,
	2021	2020	2019
	(in millions)
Cash flows from operating activities:
Net income	$268	$249	$233
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	276	254	236
Deferred tax expense (benefit) and tax credits	(79)	(15)	24
Other	11	2	(12)
Other changes in assets and liabilities:
Derivative assets	(87)	—	6
Regulatory liabilities	(67)	(93)	(42)
Deferred income taxes	132	90	20
Pension and other benefit obligations	(63)	11	(7)
Other	(20)	(32)	(35)
Net cash flows from operating activities	371	466	423
Cash flows used for investing activities:
Construction and acquisition expenditures	(686)	(606)	(519)
Other	(30)	(7)	(38)
Net cash flows used for investing activities	(716)	(613)	(557)
Cash flows from financing activities:
Common stock dividends	(168)	(160)	(144)
Capital contributions from parent	245	25	125
Proceeds from issuance of long-term debt	300	350	350
Payments to retire long-term debt	—	(150)	(250)
Net change in commercial paper	(21)	89	63
Other	(12)	(8)	(15)
Net cash flows from financing activities	344	146	129
Net decrease in cash, cash equivalents and restricted cash	(1)	(1)	(5)
Cash, cash equivalents and restricted cash at beginning of period	3	4	9
Cash, cash equivalents and restricted cash at end of period	$2	$3	$4
Supplemental cash flows information:
Cash (paid) refunded during the period for:
Interest	($101)	($102)	($103)
Income taxes, net	($38)	$13	($29)
Significant non-cash investing and financing activities:
Accrued capital expenditures	$81	$55	$82

Refer to accompanying Combined Notes to Consolidated Financial Statements.

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WISCONSIN POWER AND LIGHT COMPANY

CONSOLIDATED STATEMENTS OF EQUITY

		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
	(in millions)
2019:
Beginning balance	$66	$1,309	$775	$2,150
Net income			233	233
Common stock dividends			(144)	(144)
Capital contributions from parent		125		125
Ending balance	66	1,434	864	2,364
2020:
Net income			249	249
Common stock dividends			(160)	(160)
Capital contributions from parent		25		25
Ending balance	66	1,459	953	2,478
2021:
Net income			268	268
Common stock dividends			(168)	(168)
Capital contributions from parent		245		245
Ending balance	$66	$1,704	$1,053	$2,823

Refer to accompanying Combined Notes to Consolidated Financial Statements.

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ALLIANT ENERGY CORPORATION

INTERSTATE POWER AND LIGHT COMPANY

WISCONSIN POWER AND LIGHT COMPANY

COMBINED NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

NOTE 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

NOTE 1(a) General -

Description of Business - Alliant Energy’s financial statements include the accounts of Alliant Energy and its consolidated subsidiaries. Alliant Energy is a Midwest U.S. energy holding company, whose primary wholly-owned subsidiaries are IPL, WPL, AEF and Corporate Services.

IPL’s financial statements include the accounts of IPL and its consolidated subsidiaries, including IPL SPE LLC, which is used for IPL’s sales of accounts receivable program. IPL is a direct subsidiary of Alliant Energy and is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Iowa. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa, and is engaged in the generation and distribution of steam for two customers in Cedar Rapids, Iowa.

WPL’s financial statements include the accounts of WPL and its consolidated subsidiary. WPL is a direct subsidiary of Alliant Energy and is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Wisconsin. WPL also sells electricity to wholesale customers in Wisconsin.

AEF is comprised of Travero, ATI, corporate venture investments, a non-utility wind farm, the Sheboygan Falls Energy Facility and other non-utility holdings. Travero includes a short-line rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; freight brokerage services; and a rail-served warehouse in Iowa, which began operations in 2021. ATI, a wholly-owned subsidiary of AEF, holds all of Alliant Energy’s interest in ATC Holdings. Corporate venture investments includes various minority ownership interests in regional and national venture funds, including a coalition with different energy companies across the U.S., working together to help identify and research innovative products, technologies and business models within the emerging energy economy. The non-utility wind farm includes a 50% cash equity ownership interest in a 225 MW wind farm located in Oklahoma. The Sheboygan Falls Energy Facility is a 347 MW, simple-cycle, natural gas-fired EGU near Sheboygan Falls, Wisconsin, which is leased to WPL for an initial period of 20 years ending in 2025.

Corporate Services is the subsidiary formed to provide administrative services to Alliant Energy and its subsidiaries.

In March 2020, COVID-19 was declared a global pandemic, which has resulted in widespread travel restrictions, closures of commercial spaces and industrial facilities, and more people working from home in Alliant Energy’s service territories. For 2020 and 2021, Alliant Energy, IPL and WPL considered the impact of COVID-19 on their overall business operations, financial condition, results of operations and cash flows, along with assumptions and estimates used. In 2020, Alliant Energy, IPL and WPL experienced higher electric residential sales and lower electric commercial and industrial sales as a result of the pandemic. In 2021, changes in COVID-19 impacts resulted in lower electric residential sales and higher electric commercial and industrial sales. The degree to which the COVID-19 pandemic may impact Alliant Energy, IPL and WPL in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities.

Basis of Presentation - The financial statements reflect investments in controlled subsidiaries on a consolidated basis and Alliant Energy’s, IPL’s and WPL’s proportionate shares of jointly-owned utility EGUs. Unconsolidated investments that Alliant Energy and WPL do not control are accounted for under the equity method of accounting. Under the equity method of accounting, Alliant Energy and WPL initially record the investment at cost, and adjust the carrying amount of the investment to recognize their respective share of the earnings or losses of the investee. Dividends received from an investee reduce the carrying amount of the equity investment. Investments that do not meet the criteria for consolidation or the equity method of accounting are accounted for under the cost method.

All intercompany balances and transactions, other than certain transactions affecting the rate-making process at IPL and WPL, have been eliminated from the financial statements. Such transactions not eliminated include costs that are recoverable from customers through rate-making processes. The financial statements are prepared in conformity with GAAP, which give recognition to the rate-making practices of FERC and state commissions having regulatory jurisdiction.

Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.

Use of Estimates - The preparation of the financial statements requires management to make estimates and assumptions that affect: (a) the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements; and (b) the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

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NOTE 1(b) Regulatory Assets and Regulatory Liabilities - Alliant Energy, IPL and WPL are subject to regulation by FERC and various state regulatory commissions. As a result, Alliant Energy, IPL and WPL are subject to GAAP provisions for regulated operations, which provide that rate-regulated public utilities record certain costs and credits allowed in the rate-making process in different periods than for non-utility entities. Regulatory assets generally represent incurred costs that have been deferred as such costs are probable of recovery in future customer rates. Regulatory liabilities generally represent obligations to make refunds to customers or amounts collected in rates for which the related costs have not yet been incurred. Amounts recorded as regulatory assets or regulatory liabilities are generally recognized in the income statements at the time they are reflected in rates.

NOTE 1(c) Income Taxes - The liability method of accounting is followed for deferred taxes, which requires the establishment of deferred tax assets and liabilities, as appropriate, for temporary differences between the tax basis of assets and liabilities and the amounts reported in the financial statements. Deferred taxes are recorded using currently enacted tax rates and estimates of state apportionment. Changes in deferred tax assets and liabilities associated with certain property-related differences at IPL are accounted for differently than other subsidiaries of Alliant Energy due to rate-making practices in Iowa. Rate-making practices in Iowa do not allow the impact of certain deferred tax expenses (benefits) to be included in the determination of retail rates. Based on these rate-making practices, deferred tax expense (benefit) related to these property-related differences at IPL is not recorded in the income statement but instead recorded to regulatory assets or regulatory liabilities until these temporary differences reverse. In Wisconsin, the PSCW allows rate recovery of deferred tax expense on all temporary differences.

Investment tax credits are deferred and amortized to income over the average lives of the related property. Federal Tax Reform repealed corporate federal alternative minimum tax and allowed unutilized alternative minimum tax credits to be refunded over four tax years beginning with the U.S. federal tax return for calendar year 2018. Pursuant to the Coronavirus Aid, Relief, and Economic Security Act, Alliant Energy received the remaining alternative minimum tax credits refunds in 2020. Other tax credits reduce income tax expense in the year claimed.

Alliant Energy files a consolidated federal income tax return and a combined return in Wisconsin, which include Alliant Energy and its subsidiaries. Alliant Energy subsidiaries with a presence in Iowa file as part of a consolidated return in Iowa.

Alliant Energy allocates consolidated income tax expense to its subsidiaries that are members of the group that file a consolidated or combined income tax return. IPL and WPL use the modified separate return approach for calculating their income tax provisions and related deferred tax assets and liabilities. IPL and WPL are assumed to file separate tax returns with the federal and state taxing authorities, except that net operating losses (and other current or deferred tax attributes) are characterized as realized (or realizable) by IPL and WPL when those tax attributes are realized (or realizable) by the consolidated tax return group of Alliant Energy (even if IPL and WPL would not otherwise have realized the attributes on a stand-alone basis). The difference in the income taxes recorded for IPL and WPL under the modified separate return method compared to the income taxes recorded on a separate return basis was not material in 2021, 2020 and 2019.

NOTE 1(d) Cash, Cash Equivalents and Restricted Cash - Cash and cash equivalents include short-term liquid investments that have original maturities of less than 90 days. At December 31, 2021, Alliant Energy’s and IPL’s cash and cash equivalents included $32 million of money market fund investments, with an interest rate of 0.04%. At December 31, 2021 and 2020, Alliant Energy’s restricted cash related to requirements in Sheboygan Power, LLC’s debt agreement.

NOTE 1(e) Property, Plant and Equipment -

Utility Plant -

General - Utility plant is recorded at the original cost of acquisition or construction, which includes material, labor, contractor services, AFUDC and allocable overheads, such as supervision, engineering, benefits, certain taxes and transportation. Repairs, replacements and renewals of items of property determined to be less than a unit of property or that do not increase the property’s life or functionality are charged to maintenance expense. Property, plant and equipment that is probable of being retired early is classified as plant anticipated to be retired early. Generally, ordinary retirements of utility plant and salvage value are netted and charged to accumulated depreciation upon removal from utility plant accounts and no gain or loss is recognized consistent with rate-making principles. However, if regulators have approved recovery of the remaining net book value of property, plant and equipment that is retired early, or such approval by regulators is probable, the remaining net book value is reclassified from property, plant and equipment to regulatory assets upon retirement.

Depreciation - IPL and WPL use a combination of remaining life and straight-line depreciation methods as approved by their respective regulatory commissions. The composite or group method of depreciation is used, in which a single depreciation rate is applied to the gross investment in a particular class of property. This method pools similar assets and then depreciates each group as a whole. Periodic depreciation studies are performed to determine the appropriate group lives, net salvage, estimated cost of removal and group depreciation rates. These depreciation studies are subject to review and approval by IPL’s and WPL’s respective regulatory commissions. Depreciation expense is included within the recoverable cost of service component of rates collected from customers. The average rates of depreciation for electric, gas and other properties, consistent with current rate-making practices, were as follows:

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	IPL			WPL
	2021	2020	2019	2021	2020	2019
Electric - generation	3.4%	3.5%	3.8%	3.5%	3.5%	3.6%
Electric - distribution	2.9%	2.8%	2.9%	2.6%	2.6%	2.6%
Electric - other	5.7%	5.2%	5.3%	7.4%	6.1%	5.8%
Gas	3.3%	3.3%	3.3%	2.4%	2.4%	2.5%
Other	6.1%	6.3%	5.9%	5.4%	5.9%	5.6%

AFUDC - AFUDC represents costs to finance construction additions, including a return on equity component and cost of debt component as required by regulatory accounting. AFUDC for IPL’s construction projects is calculated in accordance with FERC guidelines. AFUDC for WPL’s retail and wholesale jurisdiction construction projects is calculated in accordance with PSCW and FERC guidelines, respectively. The AFUDC rates, computed in accordance with the prescribed regulatory formula, were as follows:

	2021	2020	2019
IPL (Wind generation CWIP)	7.0%	7.1%	7.4%
IPL (other CWIP)	7.2%	7.2%	7.5%
WPL (retail jurisdiction)	7.0%	7.0%	6.8%
WPL (wholesale jurisdiction)	5.6%	6.3%	6.9%

In accordance with their respective regulatory commission decisions, IPL applies its AFUDC rates to 100% of applicable CWIP balances and WPL generally applies its AFUDC rates to 50% of applicable CWIP balances. WPL may apply its AFUDC rates to 100% of the retail portion of the CWIP balances for construction projects requiring a CA or CPCN that were approved by the PSCW after its then most recent rate order, including West Riverside and the first and second solar generation CAs.

Non-utility and Other Property -

General - Non-utility property is recorded at the original cost of acquisition or construction, which includes material, labor and contractor services. Repairs, replacements and renewals of items of property determined to be less than a unit of property or that do not increase the property’s life or functionality are charged to maintenance expense. Upon retirement or sale of non-utility property, the original cost and related accumulated depreciation are removed from the accounts and any gain or loss is included in the income statements.

Costs related to software developed or obtained for internal use are capitalized and amortized on a straight-line basis over the estimated useful life of the related software. If software is retired prior to being fully amortized, the remaining book value is recorded as a loss in the income statements.

NOTE 1(f) Revenue Recognition -

Utility - Revenues from Alliant Energy’s utility business are primarily from electric and gas sales to customers. Utility revenues are recognized over time as services are rendered or commodities are delivered to customers, and include billed and unbilled components. The billed component is based on the reading of customers’ meters, which occurs on a systematic basis throughout each reporting period and represents the fair value of the services provided or commodities delivered. The unbilled component is estimated and recorded at the end of each reporting period based on estimated amounts of energy delivered to customers since the end of each customer’s last billing period. The unbilled component is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates.

IPL and WPL accrue revenues from their wholesale customers to the extent that the actual net revenue requirements calculated in accordance with FERC-approved formula rates for the reporting period are higher or lower than the amounts billed to wholesale customers during such period. Regulatory assets or regulatory liabilities are recorded as the offset for these accrued revenues under formulaic rate-making programs. As of December 31, 2021, the related amounts accrued for IPL and WPL were not material.

IPL and WPL participate in bid/offer-based wholesale energy and ancillary services markets operated by MISO. The MISO transactions are grouped together, resulting in a net supply to or net purchase from MISO for each hour of each day. The net supply to MISO is recorded as bulk power sales in “Electric utility revenues” and the net purchase from MISO is recorded in “Electric production fuel and purchased power” in the income statements.

Non-utility - Revenues from Alliant Energy’s non-utility businesses are primarily from its Travero business and are recognized over time as services are rendered to customers.

Taxes Collected from Customers - Sales or various other taxes collected by certain of Alliant Energy’s subsidiaries on behalf of other agencies are recorded on a net basis and are not included in revenues.

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Other - Alliant Energy, IPL and WPL do not disclose the value of unsatisfied performance obligations for: (i) contracts with an original expected length of one year or less; and (ii) contracts for which revenue is recognized at the amount to which they have the right to invoice for services performed.

NOTE 1(g) Utility Cost Recovery Mechanisms

Electric Production Fuel and Purchased Power (Fuel-related Costs) - Fuel-related costs are incurred to generate and purchase electricity to meet the demand of IPL’s and WPL’s electric customers. These fuel-related costs include the cost of fossil fuels (primarily natural gas and coal) used to produce electricity at their EGUs, and electricity purchased from MISO wholesale energy markets and under PPAs. These fuel-related costs are recorded in “Electric production fuel and purchased power” in the income statements.

IPL Retail - The cost recovery mechanisms for IPL’s retail electric customers provide for monthly adjustments to their electric rates for changes in fuel-related costs. Changes in the under-/over-collection of these costs are recognized in “Electric production fuel and purchased power” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

WPL Retail - The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. If WPL’s actual fuel-related costs fall outside these fuel monitoring ranges, WPL is authorized to defer the incremental under-/over-collection of fuel-related costs that are outside the approved ranges. Deferral of under-collections are reduced to the extent actual return on common equity earned by WPL during the fuel cost plan year exceeds the most recently authorized return on common equity. Deferred amounts for fuel-related costs outside the approved fuel monitoring ranges are recognized in “Electric production fuel and purchased power” in Alliant Energy’s and WPL’s income statements. The cumulative effects of these deferred amounts are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and WPL’s balance sheets until they are reflected in future billings to customers.

IPL and WPL Wholesale - The cost recovery mechanisms for IPL’s and WPL’s wholesale electric customers provide for subsequent adjustments to their electric rates for changes in fuel-related costs. Changes in the under-/over-collection of these costs are recognized in “Electric production fuel and purchased power” in the income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Purchased Electric Capacity - PPAs help meet the electricity demand of IPL’s and WPL’s customers. Certain PPAs include minimum payments for IPL’s and WPL’s rights to electric generating capacity, which are charged each period to “Electric production fuel and purchased power” in the income statements. Purchased electric capacity expenses are recovered from IPL’s and WPL’s retail electric customers through changes in base rates determined during periodic rate proceedings. Purchased electric capacity expenses are recovered from IPL’s and WPL’s wholesale electric customers through annual changes in base rates determined by a formula rate structure.

Electric Transmission Service - Costs incurred for the transmission of electricity to meet the demands of IPL’s and WPL’s customers are charged to “Electric transmission service” in the income statements.

IPL Retail - Electric transmission service expense is recovered from IPL’s retail electric customers through a transmission cost rider. This cost recovery mechanism provides for periodic adjustments to electric rates charged to retail electric customers for changes in electric transmission service expense. Changes in the under-/over-collection of these costs are recognized in “Electric transmission service” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

WPL Retail - Electric transmission service expense is recovered from WPL’s retail electric customers through changes in base rates determined during periodic rate proceedings. Pursuant to escrow accounting treatment approved by the PSCW, the difference between actual electric transmission service expense incurred and the amount of electric transmission service costs collected from customers as electric revenues is recognized in “Electric transmission service” in Alliant Energy’s and WPL’s income statements. An offsetting amount is recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and WPL’s balance sheets until reflected in future billings to customers.

IPL and WPL Wholesale - IPL and WPL arrange transmission service for the majority of their respective wholesale electric customers. Electric transmission service expense is allocated to and recovered from these customers based on a load ratio share computation.

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Cost of Gas Sold - Costs are incurred for the purchase, transportation and storage of natural gas to serve IPL’s and WPL’s gas customers and the costs associated with the natural gas delivered to customers are charged to “Cost of gas sold” in the income statements. The tariffs for IPL’s and WPL’s retail gas customers provide for subsequent adjustments to their rates periodically for changes in the cost of gas sold. Changes in the under-/over-collection of these costs are also recognized in “Cost of gas sold” in the income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Energy Efficiency Costs - Costs incurred to fund energy efficiency programs and initiatives that help customers reduce their energy usage are charged to “Other operation and maintenance” in the income statements. Energy efficiency costs incurred by IPL are recovered from its retail electric and gas customers through energy efficiency and demand response cost recovery factor tariffs, which are revised annually and include a reconciliation to eliminate any under-/over-collection of energy efficiency costs from prior periods. Energy efficiency costs incurred by WPL are recovered from retail electric and gas customers through changes in base rates determined during periodic rate proceedings. Reconciliations of any under-/over-collection of energy efficiency costs from prior periods are also addressed in WPL’s periodic rate proceedings. Changes in the under-/over-collection of energy efficiency costs for IPL and WPL are recognized in “Other operation and maintenance” in the income statements. The cumulative effects of the under-/over-collection of these costs for IPL and WPL are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Renewable Energy Rider - Effective with the implementation of final rates covering the 2020 forward-looking Test Period, IPL recovers a return of, as well as earn a return on, its new wind generation placed in service in 2019 and 2020 from its retail electric customers through a renewable energy rider. Other applicable costs and tax benefits associated with the new wind generation, excluding operation and maintenance expenses, are also included in the rider. This cost recovery mechanism provides for annual adjustments to electric rates charged to IPL’s retail electric customers for actual renewable energy costs and tax benefits. Changes in the under-/over-collection of these costs are recognized in “Electric utility revenue” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs for IPL are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

NOTE 1(h) Financial Instruments - Financial instruments are periodically used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. The fair value of those financial instruments that are determined to be derivatives are recorded as assets or liabilities on the balance sheets. Certain commodity purchase and sales contracts qualified for and were designated under the normal purchase and sale exception, and were accounted for on the accrual basis of accounting. Alliant Energy, IPL and WPL have elected to not net the fair value amounts of derivatives subject to a master netting arrangement by counterparty. Alliant Energy, IPL and WPL do not offset fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) against fair value amounts recognized for derivative instruments that are executed with the same counterparty under the same master netting arrangement. Refer to Note 2 for discussion of the recognition of regulatory assets and regulatory liabilities related to the unrealized losses and gains on derivative instruments. Refer to Notes 15, 16 and 17(f) for further discussion of derivatives and related credit risk.

NOTE 1(i) Asset Impairments -

Property, Plant and Equipment of Regulated Operations - Property, plant and equipment of regulated operations are reviewed for possible impairment whenever events or changes in circumstances indicate all or a portion of the carrying value of the assets may be disallowed for rate-making purposes. If IPL or WPL are disallowed recovery of any portion of, or are only allowed a partial return on, the carrying value of their regulated property, plant and equipment that is under construction, has been recently completed or is probable of abandonment, or conclude it is probable recovery or a full return will be disallowed, then an impairment charge is recognized.

Property, Plant and Equipment of Non-utility Operations - Property, plant and equipment of non-utility operations are reviewed for possible impairment whenever events or changes in circumstances indicate the carrying value of the assets may not be recoverable. Impairment is indicated if the carrying value of an asset exceeds its undiscounted future cash flows. If an impairment is indicated, a charge is recognized equal to the amount the carrying value exceeds the asset’s fair value.

Unconsolidated Equity Investments - If events or circumstances indicate the carrying value of investments accounted for under the equity method of accounting exceeds fair value and the decline in value is other than temporary, potential impairment is assessed. If an impairment is indicated, a charge is recognized equal to the amount the carrying value exceeds the investment’s fair value.

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NOTE 1(j) Asset Retirement Obligations - The fair value of a legal obligation associated with the retirement of an asset is recorded as a liability when an asset is placed in service, when a legal obligation is subsequently identified or when sufficient information becomes available to determine a reasonable estimate of the fair value of future retirement costs. When an ARO is recorded as a liability, an equivalent amount is added to the asset cost. The fair value of AROs at inception is determined using discounted cash flows analyses. The liability is accreted to its present value and the capitalized cost is depreciated over the useful life of the related asset. Accretion and depreciation expenses related to AROs for IPL’s and WPL’s regulated operations are recorded to regulatory assets on the balance sheets. Revisions in estimated cash flows for IPL’s and WPL’s regulated operations are recorded as an increase or decrease to the ARO liability, with an offset to the asset cost, unless the asset is already retired and then the offset is recorded to regulatory assets or regulatory liabilities on the balance sheets. Upon regulatory approval to recover IPL’s AROs expenditures, its regulatory assets are amortized to depreciation and amortization expenses in Alliant Energy’s and IPL’s income statements over the same time period the ARO expenditures are recovered from IPL’s customers. WPL’s regulatory assets related to AROs are recovered as a component of depreciation rates pursuant to PSCW and FERC orders. Upon settlement of the ARO liability, an entity settles the obligation for its recorded amount or incurs a gain or loss. Any gains or losses related to AROs for IPL’s and WPL’s regulated operations are recorded to regulatory liabilities or regulatory assets on the balance sheets.

NOTE 1(k) Debt Issuance and Retirement Costs - Debt issuance costs and debt premiums or discounts are presented on the balance sheets as a direct adjustment to the carrying amount of the related debt liability, and are deferred and amortized over the expected life of each debt issue, considering maturity dates and, if applicable, redemption rights held by others. Alliant Energy’s non-utility businesses and Corporate Services record to interest expense in the period of retirement any unamortized debt issuance costs and debt premiums or discounts on debt retired early.

NOTE 1(l) Current Expected Credit Losses Estimates - Current expected credit losses are estimated for trade and other receivables and credit exposures on guarantees of the performance by third parties. The current expected credit losses for short-term trade receivables are based on estimates of losses resulting from the inability of customers to make required payments. The methodology used to estimate losses is based on historical write-offs, regional economic conditions, significant events that could impact collectability, such as impacts related to COVID-19, significant weather related matters including the derecho windstorm and related regulatory actions, and forecasted changes to the accounts receivable aging portfolio and write-offs. The current expected credit losses related to guarantees of the performance by third parties are estimated using both quantitative and qualitative information, which utilizes potential outcomes in a range of possible estimated amounts.

In 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 17(d) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s equity statement for 2020.

NOTE 1(m) Variable Interest Entities - An entity is considered a VIE if its equity investors do not have sufficient equity at risk for the entity to finance its activities without additional subordinated financial support from other parties, the entity is structured with disproportionate voting rights and substantially all of the entity’s activities are conducted on behalf of the investor with disproportionately fewer voting rights, or its equity investors lack any of the following characteristics: (1) power, through voting rights or similar rights, to direct the activities of the entity that most significantly impact the entity’s economic performance; (2) the obligation to absorb expected losses of the entity; or (3) the right to receive expected benefits of the entity. The primary beneficiary of a VIE is required to consolidate the VIE. The financial statements do not reflect any consolidation of VIEs.

NOTE 1(n) Leases - The determination of whether an arrangement qualifies as a lease occurs at the inception of the arrangement. Arrangements that qualify as leases are classified as either operating or finance. Operating and finance lease liabilities represent obligations to make payments arising from the lease. Operating and finance lease assets represent the right to use an underlying asset for the lease term and are recognized at the lease commencement date based on the present value of the lease payments over the lease term. Leases with initial terms less than 12 months are not recognized as leases. For operating leases, an incremental borrowing rate, as determined at the lease commencement date, is used to determine the present value of the lease payments. For finance leases, the rate implicit in the lease, if known, is used to determine the present value of the lease payments. If the rate implicit in the lease is not known, the incremental borrowing rate is used to determine the present value of the lease payments. Lease terms include options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Operating lease expense is recognized on a straight-line basis over the expected lease term. Finance lease expense is comprised of depreciation and amortization, and interest expenses. Finance lease assets related to leased land for solar generation are amortized on a straight-line basis over the lease term, and are accounted for as operating leases for rate-making purposes. All other finance lease assets are depreciated on a straight-line basis over the shorter of the useful life of the underlying asset or the lease term.

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NOTE 2. REGULATORY MATTERS

Regulatory Assets - Alliant Energy, IPL and WPL assess whether IPL’s and WPL’s regulatory assets are probable of future recovery by considering factors such as applicable regulations, recent orders by the applicable regulatory agencies, historical treatment of similar costs by the applicable regulatory agencies and regulatory environment changes. Based on these assessments, Alliant Energy, IPL and WPL believe the regulatory assets recognized as of December 31, 2021 are probable of future recovery. However, no assurance can be made that IPL and WPL will recover all of these regulatory assets in future rates. If future recovery of a regulatory asset ceases to be probable, the regulatory asset will be charged to expense. At December 31, regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Tax-related	$934	$890	$884	$843	$50	$47
Pension and OPEB costs	462	580	228	291	234	289
AROs	128	119	89	81	39	38
Assets retired early	92	113	66	77	26	36
IPL’s DAEC PPA amendment	90	110	90	110	—	—
WPL’s Western Wisconsin gas distribution expansion investments	52	55	—	—	52	55
Commodity cost recovery	42	4	2	1	40	3
Derivatives	8	26	4	13	4	13
Other	132	113	80	67	52	46
	$1,940	$2,010	$1,443	$1,483	$497	$527

At December 31, 2021, IPL and WPL had $75 million and $13 million, respectively, of regulatory assets that were not earning a return. IPL’s regulatory assets that were not earning a return consisted primarily of retired analog electric meters, emission allowances and costs for certain construction projects. WPL’s regulatory assets that were not earning a return consisted primarily of amounts related to the wholesale portion of under-collected costs, and costs for future expansion projects. The other regulatory assets reported in the above table either earn a return or the cash has not yet been expended, in which case the assets are offset by liabilities that also do not incur a carrying cost.

Tax-related - IPL and WPL record regulatory assets for certain temporary differences (primarily related to utility property, plant and equipment at IPL) that result in a decrease in current rates charged to customers and an increase in future rates charged to customers based on the timing of income tax expense that is used to determine such rates. These temporary differences for IPL include the impacts of qualifying deductions for repairs expenditures, allocation of mixed service costs, and Iowa accelerated tax depreciation, which all contribute to lower current income tax expense during the first part of an asset’s useful life and higher current income tax expense during the latter part of an asset’s useful life. These regulatory assets will be recovered from customers in the future when these temporary differences reverse resulting in additional current income tax expense used to determine customers’ rates.

Pension and other postretirement benefits costs - The IUB, PSCW and FERC have authorized IPL and WPL to record the previously unrecognized net actuarial gains and losses, and prior service costs and credits, as regulatory assets in lieu of accumulated other comprehensive loss on the balance sheets, as these amounts are expected to be recovered in future rates. These regulatory assets will be increased or decreased as the net actuarial gains or losses, and prior service costs or credits, are subsequently amortized and recognized as a component of net periodic benefit costs. Regulatory assets are also increased or decreased as a result of the annual defined benefit plan measurement process. Pension and OPEB costs are included within the recoverable cost of service component of rates charged to IPL’s and WPL’s retail and wholesale customers, which are based upon pension and OPEB costs determined in accordance with GAAP and are calculated in accordance with IPL’s and WPL’s respective regulatory jurisdictions.

AROs - Alliant Energy, IPL and WPL believe it is probable that certain differences between expenses accrued for AROs related to their utility operations and expenses recovered currently in rates will be recoverable in future rates, and are deferring the differences as regulatory assets.

Assets retired early - IPL and WPL have retired various natural gas- and coal-fired EGUs, and IPL has retired certain analog electric meters. As a result, the remaining net book value of these assets was reclassified from property, plant and equipment to a regulatory asset on their respective balance sheets. Details regarding the recovery of the remaining net book value of these assets from IPL’s and WPL’s customers are as follows (dollars in millions):

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Entity	Asset	Retirement Date	Regulatory Asset Balance as of Dec. 31, 2021	Recovery	Regulatory Approval
IPL	Sutherland Units 1 and 3	2017	$19	Return of and return on remaining net book value through 2027	IUB and FERC
IPL	M.L. Kapp Unit 2	2018	18	Return of and return on remaining net book value through 2029	IUB and FERC
IPL	Analog electric meters	2019	29	Return of remaining net book value through 2028	IUB and FERC
WPL	Nelson Dewey Units 1 and 2 and Edgewater Unit 3	2015	6	Return of and return on remaining net book value through 2022	PSCW and FERC
WPL	Edgewater Unit 4	2018	20	Return of and return on remaining net book value through 2028	PSCW and FERC

IPL’s DAEC PPA Amendment - In September 2020, IPL made a buyout payment of $110 million in exchange for shortening the term of its DAEC PPA by 5 years. The payment was included in “DAEC PPA amendment buyout payment” in Alliant Energy’s and IPL’s cash flows used for operating activities in 2020. The buyout payment, including a return on, will be recovered from IPL’s retail and wholesale customers from 2021 through the end of 2025, and is currently being amortized to “Electric production fuel and purchased power” in Alliant Energy’s and IPL’s income statements.

WPL’s Western Wisconsin gas distribution expansion investments - WPL made contributions in aid of construction to a third party for investments as part of its Western Wisconsin gas distribution expansion project. Pursuant to authorization by the PSCW, Alliant Energy and WPL have recorded a regulatory asset for these costs, and are authorized by the PSCW to recover these amounts from WPL’s retail gas customers in base rates from 2021 through the end of 2040.

Commodity cost recovery - Refer to Note 1(g) for details of IPL’s and WPL’s commodity cost recovery mechanisms. The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. In 2021, WPL’s actual fuel-related costs fell outside these fuel monitoring ranges, resulting in a $37 million deferral as of December 31, 2021.

Derivatives - In accordance with IPL’s and WPL’s fuel and natural gas recovery mechanisms, prudently incurred costs from derivative instruments are recoverable from customers in the future after any losses are realized, and gains from derivative instruments are refundable to customers in the future after any gains are realized. Based on these recovery mechanisms, the changes in the fair value of derivative liabilities/assets resulted in comparable changes to regulatory assets/liabilities on the balance sheets.

Regulatory Liabilities - At December 31, regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Tax-related	$585	$732	$312	$331	$273	$401
Cost of removal obligations	384	367	252	238	132	129
Derivatives	166	28	77	25	89	3
Electric transmission cost recovery	51	68	27	39	24	29
WPL’s West Riverside liquidated damages	36	38	—	—	36	38
Other	49	73	23	43	26	30
	$1,271	$1,306	$691	$676	$580	$630

Tax-related regulatory liabilities reduce revenue requirement calculations utilized in IPL’s and WPL’s respective rate proceedings. Cost of removal obligations, to the extent expensed through depreciation rates, reduce rate base. A significant portion of the remaining regulatory liabilities is not used to adjust revenue requirement calculations.

Tax-related - Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities are primarily related to excess deferred tax benefits resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform. The majority of these benefits related to accelerated depreciation are subject to tax normalization rules. These rules limit the rate at which these tax benefits are allowed to be passed on to customers. In 2021, Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities decreased primarily due to returning a portion of these excess deferred tax benefits back to customers.

Cost of removal obligations - Alliant Energy, IPL and WPL collect in rates future removal costs for many assets that do not have associated AROs or that have removal costs in addition to AROs. Alliant Energy, IPL and WPL record a regulatory liability for the amounts collected in rates for these future removal costs and reduce the regulatory liability for amounts spent on removal activities. Cash payments related to cost of removal obligations are included in “Other” in cash flows used for investing activities.

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Electric transmission cost recovery - Refer to Note 1(g) for details of IPL’s and WPL’s electric transmission cost recovery mechanisms. In 2020, pursuant to an IUB order, IPL issued $42 million of credits to its retail electric customers through its transmission cost rider for amounts previously collected in rates, which resulted in a reduction to “Electric transmission service” expense in Alliant Energy’s and IPL’s income statements in 2020.

WPL’s West Riverside liquidated damages - Pursuant to terms included in the related West Riverside construction procurement contracts, WPL reached agreement with the contractor on liquidated damages in 2020. A significant portion of the liquidated damages was settled by WPL offsetting amounts owed to the contractor that were previously withheld for payment, which were non-cash investing activities. In December 2020, the PSCW authorized WPL to record the liquidated damages as a regulatory liability, which the PSCW authorized to be returned to WPL’s retail customers in 2022 and 2023.

Derecho Windstorm - In August 2020, a derecho windstorm caused considerable damage to IPL’s electric distribution system in its service territory, and over 250,000 of its customers lost power. IPL completed its initial restoration and rebuilding efforts in August 2020 and permanent repairs to the system continue. As of December 31, 2021, approximately $140 million of costs from the windstorm were recorded substantially to “Property, plant and equipment, net” on Alliant Energy’s and IPL’s balance sheets. In December 2020, IPL received approval from the IUB for utilization of a regulatory account to track certain incremental costs and benefits incurred resulting from the windstorm. These incremental costs and benefits were not addressed in the IUB’s order for IPL’s 2020 forward-looking Test Period electric subsequent proceeding, and are expected to be addressed in future regulatory proceedings. Tax benefits and the incremental operation and maintenance expenses resulting from the windstorm were deferred and recorded as a net regulatory liability of $8 million as of December 31, 2021, which is included in “Other” regulatory liabilities in the above table.

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. In October 2019, IPL reached a settlement agreement with certain intervenor groups for an annual retail electric base rate increase of $127 million. In January 2020, the IUB issued an order approving the settlement with final rates, which were effective February 26, 2020. 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. In addition, as discussed in Note 1(g), the net impact of certain costs and benefits resulting from IPL’s 1,000 MW expansion of wind generation in 2019 and 2020 is being recovered from its retail electric customers through the renewable energy rider. The agreement also includes IPL providing retail electric billing credits, which began in the third quarter of 2020 through June 2021, and in aggregate include $27 million of excess deferred tax benefits and $8 million from a partial refund of interim rates implemented in 2019. In 2021, the IUB issued an order for IPL’s 2020 forward-looking Test Period electric subsequent proceeding, which compared actual revenues and costs to those initially forecasted by IPL, and authorized IPL to maintain its current retail electric rates.

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. In October 2019, IPL reached a settlement agreement with intervenor groups for an annual retail gas base rate increase of $12 million. In December 2019, the IUB issued an order approving the settlement with final rates, which were effective January 10, 2020. In 2021, the IUB issued an order for IPL’s 2020 forward-looking Test Period gas subsequent proceeding, which compared actual revenues and costs to those initially forecasted by IPL, and authorized IPL to maintain its current retail gas rates.

WPL’s Retail Electric and Gas Rate Review (2019/2020 Forward-looking Test Period) - In December 2018, the PSCW issued an order approving WPL’s proposed settlement for its retail electric and gas rate review covering the 2019/2020 Test Period, which was based on a stipulated agreement between WPL and intervenor groups. Under the settlement, WPL retail electric and gas base rates did not change from then current levels through the end of 2020. In September 2020, pursuant to an August 2020 PSCW order, WPL refunded $12 million of 2019 fuel-related cost over-collections to its retail electric customers. In addition, WPL’s amortization of excess deferred taxes resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform was used to offset increases in WPL’s 2020 increased revenue requirements.

WPL’s Retail Electric and Gas Rate Review (2021 Forward-looking Test Period) - In December 2020, the PSCW issued an order authorizing WPL to maintain its then current retail electric and gas base rates, authorized return on common equity, regulatory capital structure and earnings sharing mechanism through the end of 2021. WPL utilized anticipated fuel-related cost savings and excess deferred income tax benefits in 2021 to offset the revenue requirement impacts of increasing electric and gas rate base, including the Kossuth wind farm, which was placed in service in October 2020, and the expansion of its gas distribution system in Western Wisconsin, which was placed in service in November 2020.

WPL’s Retail Fuel-related Rate Filing (2020 Forward-looking Test Period) - In December 2019, WPL received an order from the PSCW authorizing an annual retail electric rate decrease of $29 million, or approximately 2%, effective January 1, 2020. The decrease primarily reflected a change in expected fuel-related costs in 2020.

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NOTE 3. 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
	2021	2020	2021	2020	2021	2020
Utility:
Electric plant:
Generation in service	$7,539	$8,222	$4,922	$4,884	$2,617	$3,338
Distribution in service	6,537	6,216	3,652	3,470	2,885	2,746
Other in service	540	536	363	358	177	178
Anticipated to be retired early (a)	2,094	1,269	487	459	1,607	810
Total electric plant	16,710	16,243	9,424	9,171	7,286	7,072
Gas plant in service	1,636	1,563	878	844	758	719
Other plant in service	621	534	398	354	223	180
Accumulated depreciation	(5,263)	(4,868)	(2,897)	(2,671)	(2,366)	(2,197)
Net plant	13,704	13,472	7,803	7,698	5,901	5,774
Leased Sheboygan Falls Energy Facility, net (b)	—	—	—	—	21	27
Leased land for solar generation, net	11	—	—	—	11	—
Construction work in progress	778	405	174	185	604	220
Other, net	7	7	6	6	1	1
Total utility	14,500	13,884	7,983	7,889	6,538	6,022
Non-utility and other:
Non-utility Generation, net (c)	75	79	—	—	—	—
Corporate Services and other, net (d)	412	373	—	—	—	—
Total non-utility and other	487	452	—	—	—	—
Total property, plant and equipment	$14,987	$14,336	$7,983	$7,889	$6,538	$6,022

(a)In 2020, IPL and WPL received approval from MISO to retire Lansing and Edgewater Unit 5, respectively, and currently anticipate retiring Lansing by the end of 2022 and Edgewater Unit 5 by early 2023. In 2021, WPL received approval from MISO to retire Columbia Units 1 and 2, and currently anticipates retiring Columbia Unit 1 by the end of 2023 and Columbia Unit 2 by the end of 2024. Alliant Energy and IPL concluded that Lansing, and Alliant Energy and WPL concluded that Edgewater Unit 5 and Columbia Units 1 and 2, met the criteria to be considered probable of abandonment as of December 31, 2021. IPL and WPL are currently allowed a full recovery of and a full return on its respective EGUs from both its retail and wholesale customers, and as a result, Alliant Energy, IPL and WPL concluded that no disallowance was required as of December 31, 2021. As of December 31, 2021, net book values were $245 million for Lansing, $527 million for Edgewater Unit 5, and $460 million for Columbia Units 1 and 2 in aggregate.

(b)Less accumulated amortization of $100 million and $95 million for WPL as of December 31, 2021 and 2020, respectively. For Alliant Energy, the leased Sheboygan Falls Energy Facility is eliminated 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 $67 million and $63 million for Alliant Energy as of December 31, 2021 and 2020, respectively.

(d)Less accumulated depreciation of $245 million and $210 million for Alliant Energy as of December 31, 2021 and 2020, 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
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Equity	$18	$39	$66	$7	$17	$35	$11	$22	$31
Debt	7	16	27	2	7	15	5	9	12
	$25	$55	$93	$9	$24	$50	$16	$31	$43

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 in 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

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Travero assets (a short-line rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; freight brokerage services; and a rail-served warehouse in Iowa, which began operations in 2021). All Corporate Services and Other property, plant and equipment are depreciated using the straight-line method over periods ranging from 5 to 30 years.

NOTE 4. JOINTLY-OWNED ELECTRIC UTILITY PLANT

Under joint ownership agreements with other utilities, IPL and WPL have undivided ownership interests in jointly-owned EGUs. Each of the respective owners is responsible for the financing of its portion of the construction costs. IPL’s and WPL’s shares of expenses from jointly-owned EGUs are included in the corresponding operating expenses (e.g., electric production fuel, other operation and maintenance, etc.) in the income statements. Information relative to IPL’s and WPL’s ownership interest in these jointly-owned EGUs at December 31, 2021 was as follows (dollars in millions):

	Ownership	Electric	Accumulated Provision	Construction
	Interest %	Plant	for Depreciation	Work in Progress
IPL
Ottumwa Unit 1	48.0%	$599	$214	$11
George Neal Unit 4	25.7%	193	100	2
George Neal Unit 3	28.0%	173	74	3
Louisa Unit 1	4.0%	40	23	—
		1,005	411	16
WPL
Columbia Units 1-2	53.5%	802	314	6
West Riverside Energy Center and Solar Garden	91.0%	706	33	3
Forward Wind Energy Center	42.6%	118	48	—
		1,626	395	9
Alliant Energy		$2,631	$806	$25

NOTE 5. RECEIVABLES

NOTE 5(a) Accounts Receivable - Details for accounts receivable included on the balance sheets as of December 31 were as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Customer	$93	$101	$—	$—	$82	$92
Unbilled utility revenues	91	82	—	—	91	82
Deferred proceeds	214	188	214	188	—	—
Other	53	59	28	23	25	35
Allowance for expected credit losses	(11)	(18)	(1)	(1)	(10)	(17)
	$440	$412	$241	$210	$188	$192

NOTE 5(b) Sales of Accounts Receivable - IPL maintains a Receivables Agreement whereby it may sell its customer accounts receivables, unbilled revenues and certain other accounts receivables to a third party through wholly-owned and consolidated special purpose entities. In April 2021, IPL amended and extended through March 2023 the purchase commitment from the third party to which it sells its receivables. IPL pays a monthly fee to the third party that varies based on interest rates, limits on cash proceeds and cash amounts received from the third party. Deferred proceeds represent IPL’s interest in the receivables sold to the third party. At IPL’s request, deferred proceeds are paid to IPL from collections of receivables, after paying any required expenses incurred by the third party and the collection agent. Corporate Services acts as collection agent for the third party and receives a fee for collection services. The Receivables Agreement can be terminated by the third party if arrears or write-offs exceed certain levels. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. IPL believes that the allowance for expected credit losses related to its sales of receivables is a reasonable approximation of credit risk of the customers that generated the receivables. Refer to Note 16 for discussion of the fair value of deferred proceeds.

Under the Receivables Agreement, IPL has the right to receive cash proceeds, up to a certain limit, from the third party in exchange for the receivables sold. Effective April 2021, the limit on cash proceeds is $110 million. Cash proceeds are used by IPL to meet short-term financing needs, and cannot exceed the current limit or amount of receivables available for sale, whichever is less. As of December 31, 2021, IPL had $109 million of available capacity under its sales of accounts receivable program. IPL’s maximum and average outstanding aggregate cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program were as follows (in millions):

	Maximum			Average
	2021	2020	2019	2021	2020	2019
Outstanding aggregate cash proceeds	$110	$96	$108	$46	$9	$36

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As of December 31, the attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

	2021	2020
Customer accounts receivable	$125	$114
Unbilled utility revenues	104	92
Receivables sold to third party	229	206
Less: cash proceeds	1	1
Deferred proceeds	228	205
Less: allowance for expected credit losses	14	17
Fair value of deferred proceeds	$214	$188
Outstanding receivables past due	$22	$27

Additional attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

	2021	2020	2019
Collections	$2,134	$2,025	$2,193
Write-offs, net of recoveries	9	7	19

NOTE 6. 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, 2021	2021	2020	2021	2020	2019
ATC Holdings	16%, 20%	$338	$331	($43)	($47)	($45)
Non-utility wind farm in Oklahoma	50%	99	103	(4)	(8)	(5)
Corporate venture investments	Various	52	31	(13)	(4)	(1)
Other	Various	19	11	(2)	(2)	(2)
		$508	$476	($62)	($61)	($53)

Summary aggregate financial information from the financial statements of these holdings is as follows (in millions):

	Alliant Energy
	2021	2020	2019
Revenues	$802	$801	$783
Operating income	357	376	359
Net income	358	343	340
As of December 31:
Current assets	112	121
Non-current assets	7,036	6,388
Current liabilities	455	317
Non-current liabilities	3,110	2,997
Noncontrolling interest	247	192

ATC Holdings - As of December 31, 2021, 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.

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 coalition with different energy companies across the U.S., working together to help identify and research innovative products, technologies and business models within the emerging energy economy.

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NOTE 7. COMMON EQUITY

Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows:

	2021	2020	2019
Shares outstanding, January 1	249,868,415	245,022,800	236,063,279
Equity forward agreements	—	4,275,127	8,358,973
Shareowner Direct Plan	492,565	472,283	501,808
Equity-based compensation plans	113,549	98,205	101,478
Other	—	—	(2,738)
Shares outstanding, December 31	250,474,529	249,868,415	245,022,800

At December 31, 2021, Alliant Energy had a total of 14 million shares available for issuance in the aggregate, pursuant to its 2020 OIP, Shareowner Direct Plan and 401(k) Savings Plan.

Equity Forward Agreements - In 2018, Alliant Energy entered into forward sale agreements with various counterparties in connection with a public offering of 8,358,973 shares of Alliant Energy common stock. In 2019, Alliant Energy settled $366 million under the forward sale agreements by delivering 8,358,973 shares of newly issued Alliant Energy common stock at a weighted average forward sale price of $43.75 per share. Alliant Energy used the net proceeds from the settlements for general corporate purposes.

In 2019, Alliant Energy entered into forward sale agreements with a counterparty in connection with a public offering of 4,275,127 shares of Alliant Energy common stock. In 2020, Alliant Energy settled $222 million under the forward sale agreements by delivering 4,275,127 shares of newly issued Alliant Energy common stock at a weighted average forward sale price of $51.98 per share. Alliant Energy used the net proceeds from the settlements for general corporate purposes.

Shareowner Direct Plan - Alliant Energy satisfies its requirements under the Shareowner Direct Plan (dividend reinvestment and stock purchase plan) by acquiring Alliant Energy common stock through original issue, rather than on the open market.

NOTE 8. PREFERRED STOCK

IPL is authorized to issue up to 16,000,000 shares of cumulative preferred stock in aggregate. Information related to IPL’s cumulative preferred stock at December 31, 2020 was as follows (dollars in millions):

Series	Liquidation Preference/Stated Value	Shares Authorized	Shares Outstanding	Carrying Value
5.1%	$25	8,000,000	8,000,000	$200

In December 2021, IPL redeemed all 8,000,000 outstanding shares of its 5.1% cumulative preferred stock at the $25 per share par value for $200 million plus accrued and unpaid dividends up to the redemption date. In 2021, Alliant Energy and IPL recorded a $5 million non-cash charge related to this transaction in “Preferred dividend requirements” in their income statements.

NOTE 9. DEBT

NOTE 9(a) Short-term Debt - Alliant Energy and its subsidiaries maintain committed bank lines of credit to provide short-term borrowing flexibility and back-stop liquidity for commercial paper outstanding. At December 31, 2021, the short-term borrowing capacity under a single credit facility agreement, which expires in December 2026, totaled $1 billion ($450 million for Alliant Energy at the parent company level, $250 million for IPL and $300 million for WPL). Subject to certain conditions, Alliant Energy (at the parent company level), IPL and WPL may each reallocate and change its sublimit up to $500 million, $400 million and $500 million, respectively, within the $1 billion total commitment. Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, classified as short-term debt was as follows (dollars in millions):

	Alliant Energy		IPL		WPL
December 31	2021	2020	2021	2020	2021	2020
Amount outstanding	$515	$389	$—	$—	$236	$257
Weighted average interest rates	0.2%	0.2%	N/A	N/A	0.2%	0.1%
Available credit facility capacity	$485	$611	$250	$250	$64	$43

	Alliant Energy		IPL		WPL
For the year ended	2021	2020	2021	2020	2021	2020
Maximum amount outstanding (based on daily outstanding balances)	$648	$495	$19	$8	$320	$266
Average amount outstanding (based on daily outstanding balances)	$459	$292	$—	$—	$172	$117
Weighted average interest rates	0.2%	0.7%	0.2%	0.5%	0.1%	0.7%

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NOTE 9(b) Long-Term Debt - Long-term debt, net as of December 31 was as follows (dollars in millions):

	2021			2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Senior Debentures (a):
3.25%, due 2024	$500	$500	$—	$500	$500	$—
3.4%, due 2025	250	250	—	250	250	—
5.5%, due 2025	50	50	—	50	50	—
4.1%, due 2028	500	500	—	500	500	—
3.6%, due 2029	300	300	—	300	300	—
2.3%, due 2030	400	400	—	400	400	—
6.45%, due 2033	100	100	—	100	100	—
6.3%, due 2034	125	125	—	125	125	—
6.25%, due 2039	300	300	—	300	300	—
4.7%, due 2043	250	250	—	250	250	—
3.7%, due 2046	300	300	—	300	300	—
3.5%, due 2049	300	300	—	300	300	—
3.1%, due 2051 (b)	300	300	—	—	—	—
	3,675	3,675	—	3,375	3,375	—
Debentures (a):
2.25%, due 2022	250	—	250	250	—	250
3.05%, due 2027	300	—	300	300	—	300
3%, due 2029	350	—	350	350	—	350
1.95%, due 2031 (c)	300	—	300	—	—	—
6.25%, due 2034	100	—	100	100	—	100
6.375%, due 2037	300	—	300	300	—	300
7.6%, due 2038	250	—	250	250	—	250
4.1%, due 2044	250	—	250	250	—	250
3.65%, due 2050	350	—	350	350	—	350
	2,450	—	2,450	2,150	—	2,150
Other:
AEF term loan credit agreement through March 2022, 1% at December 31, 2021 (with Alliant Energy as guarantor)	300	—	—	300	—	—
Corporate Services 3.45% senior notes, due 2022 (a)	75	—	—	75	—	—
AEF 3.75% senior notes, due 2023 (with Alliant Energy as guarantor) (a)	400	—	—	400	—	—
AEF 1.4% senior notes, due 2026 (with Alliant Energy as guarantor) (a)	200	—	—	200	—	—
AEF 4.25% senior notes, due 2028 (with Alliant Energy as guarantor) (a)	300	—	—	300	—	—
Sheboygan Power, LLC 5.06% senior secured notes, due 2022 to 2024 (secured by the Sheboygan Falls Energy Facility and related assets) (a)	24	—	—	31	—	—
Other, 1% at December 31, 2021, due 2022 to 2025	1	—	—	2	—	—
	1,300	—	—	1,308	—	—
Subtotal	7,425	3,675	2,450	6,833	3,375	2,150
Current maturities	(633)	—	(250)	(8)	—	—
Unamortized debt issuance costs	(42)	(23)	(15)	(41)	(22)	(14)
Unamortized debt (discount) and premium, net	(15)	(9)	(6)	(15)	(8)	(6)
Long-term debt, net (d)	$6,735	$3,643	$2,179	$6,769	$3,345	$2,130

(a)Contains optional redemption provisions which, if elected by the issuer at its sole discretion, could require material redemption premium payments by the issuer. The redemption premium payments under these optional redemption provisions are variable and dependent on applicable U.S. Treasury rates at the time of redemption.

(b)In November 2021, IPL issued $300 million of 3.1% senior debentures due 2051. The net proceeds from the issuance were used by IPL to retire its cumulative preferred stock in 2021 and for general corporate purposes.

(c)In September 2021, WPL issued $300 million of 1.95% debentures due 2031. The debentures were issued as green bonds, and an amount in excess of the net proceeds was disbursed for the construction and development of WPL’s wind and solar EGUs.

(d)There were no significant sinking fund requirements related to the outstanding long-term debt.

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Five-Year Schedule of Long-term Debt Maturities - At December 31, 2021, long-term debt maturities for 2022 through 2026 were as follows (in millions):

	2022	2023	2024	2025	2026
IPL	$—	$—	$500	$300	$—
WPL	250	—	—	—	—
Corporate Services	75	—	—	—	—
AEF	308	408	9	—	200
Alliant Energy	$633	$408	$509	$300	$200

Fair Value of Long-term Debt - Refer to Note 16 for information on the fair value of long-term debt outstanding.

NOTE 10. LEASES

Operating Leases - Alliant Energy’s, IPL’s and WPL’s operating leases primarily include leases of space on telecommunication towers and leases of property. Operating lease details are as follows (dollars in millions):

	December 31, 2021			December 31, 2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Property, plant and equipment, net	$14	$9	$5	$15	$9	$6
Other current liabilities	$2	$1	$1	$2	$1	$1
Other liabilities	12	8	4	13	8	5
Total operating lease liabilities	$14	$9	$5	$15	$9	$6
Weighted average remaining lease term	9 years	11 years	8 years	10 years	11 years	9 years
Weighted average discount rate	4%	4%	4%	4%	4%	4%

Finance Leases - WPL is currently leasing the Sheboygan Falls Energy Facility from AEF’s Non-utility Generation business through 2025, the initial lease term. WPL is responsible for the operation of the EGU and has exclusive rights to its output. This finance lease contains two lease renewal periods, which are not included in the finance lease obligation, as well as an option to purchase the facility at the end of the initial lease term. For Alliant Energy, the leased Sheboygan Falls Energy Facility is eliminated upon consolidation and is therefore is not reflected in Alliant Energy’s amounts below.

Related to its investments in solar generation, WPL entered into land lease agreements with unaffiliated parties that commenced in 2021. The leases have various terms with optional renewal periods that are assumed to be extended through the end of the estimated useful lives of the solar generating facilities. The leases do not contain purchase options and are fixed lease payments.

Finance lease details are as follows (dollars in millions):

	Alliant Energy	WPL
	December 31, 2021	December 31, 2021	December 31, 2020
Property, plant and equipment, net:
Sheboygan Falls Energy Facility	n/a	$21	$27
Leased land for solar generation	$11	11	—
	$11	$32	$27
Other current liabilities:
Sheboygan Falls Energy Facility	n/a	$10	$9
Leased land for solar generation	$1	1	—
	1	11	9
Other liabilities:
Sheboygan Falls Energy Facility	n/a	31	42
Leased land for solar generation	11	11	—
	11	42	42
Total finance lease liabilities	$12	$53	$51
Weighted average remaining lease term	34 years	10 years	4 years
Weighted average discount rate	3%	9%	11%
	2021	2021	2020	2019
Depreciation and amortization expenses	$—	$6	$6	$6
Interest expense	—	5	6	7
Total finance lease expense	$—	$11	$12	$13

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Expected Maturities - As of December 31, 2021, expected maturities of lease liabilities were as follows (in millions):

	2022	2023	2024	2025	2026	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$2	$2	$2	$2	$2	$7	$17	$3	$14
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	1	6	1	5
Finance Leases:
Alliant Energy	—	—	—	—	1	19	20	8	12
WPL	15	15	15	6	1	19	71	18	53

NOTE 11. REVENUES

Revenues from Alliant Energy’s, IPL’s and WPL’s utility businesses are primarily from electric and gas sales provided to customers based on approved tariffs or specific contracts with customers. IPL’s and WPL’s primary performance obligations under such arrangements are to deliver electricity and gas, and their customers simultaneously receive and consume the electricity and gas. For such arrangements, revenues are recognized equivalent to the value of the electricity or gas supplied during each period, including amounts billed during each period and changes in amounts estimated to be billed at the end of each period. IPL and WPL apply the right to invoice method to measure progress towards completing performance obligations to transfer electricity and gas to their customers.

IPL provides retail electric and gas service to customers in Iowa, and WPL provides retail and wholesale electric and retail gas service to customers in Wisconsin. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa, as well as steam from its Prairie Creek Generating Station to high-pressure steam customers in Iowa.

IPL’s and WPL’s retail electric and gas revenues include sales to residential, commercial and industrial customers. IPL’s and WPL’s retail electric and gas customer prices are based on IPL’s and WPL’s cost of service and are determined through general rate review proceedings and various tariff filings with the IUB and PSCW, respectively. Such tariff-based services provide electricity or gas to customers without a defined contractual term.

IPL and WPL have wholesale electric market-based rate authority from FERC allowing them to participate in wholesale energy markets (e.g. MISO) and transact directly with third parties. This authority from FERC allows sales of electricity referred to as bulk power sales based on current market values. FERC also allows IPL and WPL to enter into power supply agreements with municipalities and rural electric cooperatives with defined contractual terms, which include standard pricing mechanisms that are detailed in current tariffs accepted by FERC through wholesale rate review proceedings.

Revenues from Alliant Energy’s non-utility business customers are primarily from its Travero business, which includes a short-line rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; freight brokerage services; and a rail-served warehouse in Iowa, which began operations in 2021.

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Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Electric Utility:
Retail - residential	$1,115	$1,093	$1,092	$620	$602	$601	$495	$491	$491
Retail - commercial	763	718	770	508	474	510	255	244	260
Retail - industrial	893	841	889	505	488	504	388	353	385
Wholesale	187	168	177	57	57	64	130	111	113
Bulk power and other	123	100	136	62	74	102	61	26	34
Total Electric Utility	3,081	2,920	3,064	1,752	1,695	1,781	1,329	1,225	1,283
Gas Utility:
Retail - residential	257	214	259	146	116	149	111	98	110
Retail - commercial	139	107	133	79	59	75	60	48	58
Retail - industrial	17	12	16	12	8	12	5	4	4
Transportation/other	43	40	47	28	25	28	15	15	19
Total Gas Utility	456	373	455	265	208	264	191	165	191
Other Utility:
Steam	36	36	37	36	36	37	—	—	—
Other utility	13	13	9	10	8	7	3	5	2
Total Other Utility	49	49	46	46	44	44	3	5	2
Non-Utility and Other:
Travero and other	83	74	83	—	—	—	—	—	—
Total Non-Utility and Other	83	74	83	—	—	—	—	—	—
Total revenues	$3,669	$3,416	$3,648	$2,063	$1,947	$2,089	$1,523	$1,395	$1,476

NOTE 12. INCOME TAXES

Income Tax Expense (Benefit) - The components of “Income tax expense (benefit)” in the income statements were as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Current tax expense (benefit):
Federal	$1	$1	($7)	($21)	$6	($11)	$22	($11)	$12
State	3	8	24	(1)	(1)	24	6	7	13
IPL’s tax benefit riders	—	—	(4)	—	—	(4)	—	—	—
Deferred tax expense (benefit):
Federal	9	22	70	73	30	26	(75)	(9)	31
State	15	8	42	—	(2)	31	11	10	6
Production tax credits	(101)	(95)	(55)	(87)	(80)	(42)	(14)	(15)	(13)
Investment tax credits	(1)	(1)	(1)	—	—	—	(1)	(1)	—
	($74)	($57)	$69	($36)	($47)	$24	($51)	($19)	$49

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Income Tax Rates - The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	Alliant Energy						IPL						WPL
	2021		2020		2019		2021		2020		2019		2021		2020		2019
Statutory federal income tax rate	21	%	21	%	21	%	21	%	21	%	21	%	21	%	21	%	21	%
State income taxes, net of federal benefits	2		2		7		(1)		(1)		8		6		6		6
Amortization of excess deferred taxes (Refer to Note 2)	(18)		(13)		(1)		(4)		(5)		—		(43)		(26)		(2)
Production tax credits	(17)		(17)		(9)		(27)		(28)		(13)		(6)		(7)		(5)
Effect of rate-making on property-related differences	(1)		(3)		(6)		(2)		(4)		(10)		(1)		(2)		(3)
Adjustment for prior period taxes	1		1		1		2		1		3		—		—		—
IPL’s tax benefit riders	—		—		(1)		—		—		(1)		—		—		—
Other items, net	—		(1)		(1)		—		—		—		(1)		—		—
Overall income tax rate	(12	%)	(10	%)	11	%	(11	%)	(16	%)	8	%	(24	%)	(8	%)	17	%

Deferred Tax Assets and Liabilities - The deferred tax assets and liabilities included on the balance sheets at December 31 arise from the following temporary differences (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Deferred tax liabilities:
Property	$2,389	$2,232	$1,416	$1,312	$913	$854
ATC Holdings	123	116	—	—	—	—
Other	111	101	76	83	50	41
Total deferred tax liabilities	2,623	2,449	1,492	1,395	963	895
Deferred tax assets:
Federal credit carryforwards	560	454	345	258	192	175
Net operating losses carryforwards - federal	39	77	36	71	—	1
Net operating losses carryforwards - state	38	37	3	1	—	—
Other	65	73	25	30	18	18
Subtotal deferred tax assets	702	641	409	360	210	194
Valuation allowances	(6)	(6)	—	—	—	(1)
Total deferred tax assets	696	635	409	360	210	193
Total deferred tax liabilities, net	$1,927	$1,814	$1,083	$1,035	$753	$702

Carryforwards - At December 31, 2021, carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy	IPL	WPL
Federal net operating losses	2037	$186	$172	$1
State net operating losses	2022-2041	619	28	2
Federal tax credits	2022-2041	560	345	192

Valuation Allowances - Alliant Energy currently expects its federal net operating losses carryforwards will not be fully utilized until 2023. Because taxable income must be reduced by federal net operating losses carryforwards prior to utilizing federal tax credit carryforwards, Alliant Energy currently does not expect to utilize 2002 vintage federal credit carryforwards prior to their expiration in 2022, resulting in valuation allowances as of December 31, 2021.

Uncertain Tax Positions - At December 31, 2021, 2020 and 2019, there were no uncertain tax positions or penalties accrued related to uncertain tax positions. As of December 31, 2021, no material changes to unrecognized tax benefits are expected during the next 12 months.

Open tax years - Tax years that remain subject to the statute of limitations in the major jurisdictions for each of Alliant Energy, IPL and WPL are as follows:

Consolidated federal income tax returns (a)	2018	-	2020
Consolidated Iowa income tax returns (b)	2018	-	2020
Wisconsin combined tax returns (c)	2017	-	2020

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(a)The 2018 and 2019 federal tax returns are effectively settled as a result of participation in the IRS Compliance Assurance Program, which allows Alliant Energy and the IRS to work together to resolve issues related to Alliant Energy’s current tax year before filing its federal income tax return. The statute of limitations for these federal tax returns expires three years from each filing date.

(b)The statute of limitations for these Iowa tax returns expires three years from each filing date.

(c)The statute of limitations for these Wisconsin combined tax returns expires four years from each filing date.

Iowa Tax Reform - In 2018, Iowa tax reform was enacted, resulting in a reduction in the Iowa income tax rate from 12% to 9.8%, effective January 1, 2021, and the elimination of the deduction for federal income taxes, effective January 1, 2022, for taxes related to 2020 and prior.

NOTE 13. BENEFIT PLANS

NOTE 13(a) Pension and Other Postretirement Benefits Plans - Retirement benefits are provided to substantially all employees through various qualified and non-qualified non-contributory defined benefit pension plans (currently closed to new hires), and/or through defined contribution plans (including 401(k) savings plans). Benefits of the non-contributory defined benefit pension plans are based on the plan participant’s years of service, age and compensation. Benefits of the defined contribution plans are based on the plan participant’s years of service, age, compensation and contributions. Certain defined benefit postretirement health care and life benefits are provided to eligible retirees. In general, the retiree health care plans consist of fixed benefit subsidy structures and the retiree life insurance plans are non-contributory.

IPL and WPL account for their participation in Alliant Energy and Corporate Services sponsored plans as multiple-employer plans. For IPL and WPL, amounts below represent the amounts for their plan participants covered under plans they sponsor, as well as amounts directly assigned to them related to certain participants in the Alliant Energy and Corporate Services sponsored plans.

Assumptions - The assumptions for defined benefit pension and OPEB plans at the measurement date of December 31 were as follows:

	Defined Benefit Pension Plans									OPEB Plans
Alliant Energy	2021			2020			2019			2021	2020	2019
Discount rate for benefit obligations	2.91%			2.57%			3.48%			2.81%	2.31%	3.40%
Discount rate for net periodic cost	2.57%			3.48%			4.34%			2.31%	3.40%	4.24%
Expected rate of return on plan assets	7.10%			7.10%			7.60%			4.80%	4.50%	5.44%
Interest crediting rate for Alliant Energy Cash Balance Pension Plan	4.18%			4.76%			5.52%			N/A	N/A	N/A
Rate of compensation increase	3.30%	-	4.50%	3.65%	-	4.50%	3.65%	-	4.50%	N/A	N/A	N/A

	Qualified Defined Benefit Pension Plan			OPEB Plans
IPL	2021	2020	2019	2021	2020	2019
Discount rate for benefit obligations	2.94%	2.61%	3.51%	2.80%	2.28%	3.39%
Discount rate for net periodic cost	2.61%	3.51%	4.35%	2.28%	3.39%	4.23%
Expected rate of return on plan assets	7.10%	7.10%	7.60%	5.10%	4.50%	5.60%
Rate of compensation increase	3.30%	3.65%	3.65%	N/A	N/A	N/A

	Qualified Defined Benefit Pension Plan			OPEB Plans
WPL	2021	2020	2019	2021	2020	2019
Discount rate for benefit obligations	2.94%	2.64%	3.50%	2.79%	2.27%	3.39%
Discount rate for net periodic cost	2.64%	3.50%	4.35%	2.27%	3.39%	4.23%
Expected rate of return on plan assets	7.10%	7.10%	7.60%	4.02%	3.28%	3.81%
Rate of compensation increase	3.30%	3.65%	3.65%	N/A	N/A	N/A

Expected rate of return on plan assets - The expected rate of return on plan assets is based on projected asset class returns using target allocations. A forward-looking building blocks approach is used, and historical returns, survey information and capital market information are analyzed to support the expected rate of return on plan assets assumption. Refer to “Investment Strategy for Plan Assets” below for additional information related to investment strategy and mix of assets for the pension and OPEB plans.

Life Expectancy - The life expectancy assumption is used in determining the benefit obligation and net periodic benefit cost for defined benefit pension and OPEB plans. This assumption utilizes base mortality tables that were released in 2019 by the Society of Actuaries and mortality projection tables that were released in 2020 by the Society of Actuaries.

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Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans are included below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements.

Alliant Energy	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$11	$11	$10	$4	$3	$3
Interest cost	34	43	50	5	7	9
Expected return on plan assets (a)	(69)	(70)	(60)	(5)	(5)	(5)
Amortization of prior service credit (b)	—	—	(1)	—	—	—
Amortization of actuarial loss (c)	39	34	36	5	3	3
Settlement losses (d)	—	12	—	—	—	—
	$15	$30	$35	$9	$8	$10

IPL	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$7	$7	$6	$1	$1	$1
Interest cost	16	20	23	2	3	3
Expected return on plan assets (a)	(32)	(33)	(28)	(3)	(4)	(4)
Amortization of actuarial loss (c)	17	15	15	2	1	2
Settlement losses (d)	—	7	—	—	—	—
	$8	$16	$16	$2	$1	$2

WPL	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$4	$4	$3	$1	$2	$1
Interest cost	15	19	21	2	3	3
Expected return on plan assets (a)	(31)	(31)	(26)	—	(1)	(1)
Amortization of prior service credit (b)	—	—	—	—	(1)	—
Amortization of actuarial loss (c)	19	16	18	2	2	2
	$7	$8	$16	$5	$5	$5

(a)The expected return on plan assets is based on the expected rate of return on plan assets and the fair value approach to the market-related value of plan assets.

(b)Unrecognized prior service credits for the OPEB plans are amortized over the average future service period to full eligibility of the participants of each plan.

(c)Unrecognized net actuarial gains or losses in excess of 10% of the greater of the plans’ benefit obligations or assets are amortized over the average future service lives of plan participants, except for the Alliant Energy Cash Balance Pension Plan where gains or losses outside the 10% threshold are amortized over the time period the participants are expected to receive benefits.

(d)Settlement losses related to payments made to retired executives of Alliant Energy and lump sum payments related to IPL’s qualified defined benefit pension plan.

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Benefit Plan Assets and Obligations - A reconciliation of the funded status of qualified and non-qualified defined benefit pension and OPEB plans to the amounts recognized on the balance sheets at December 31 was as follows (in millions):

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$1,351	$1,280	$227	$214
Service cost	11	11	4	3
Interest cost	34	43	5	7
Plan participants’ contributions	—	—	5	4
Actuarial (gain) loss	(46)	132	(12)	18
Gross benefits paid	(99)	(115)	(19)	(19)
Net benefit obligation at December 31	1,251	1,351	210	227
Change in plan assets:
Fair value of plan assets at January 1	984	931	108	105
Actual return on plan assets	87	108	4	11
Employer contributions	39	60	8	7
Plan participants’ contributions	—	—	5	4
Gross benefits paid	(99)	(115)	(19)	(19)
Fair value of plan assets at December 31	1,011	984	106	108
Under funded status at December 31	($240)	($367)	($104)	($119)

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$13	$8
Current liabilities	(2)	(2)	(8)	(8)
Pension and other benefit obligations	(238)	(365)	(109)	(119)
Net amounts recognized at December 31	($240)	($367)	($104)	($119)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$429	$533	$38	$54
Prior service credit	(4)	(5)	(1)	(1)
	$425	$528	$37	$53

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$615	$581	$91	$86
Service cost	7	7	1	1
Interest cost	16	20	2	3
Plan participants’ contributions	—	—	2	1
Actuarial (gain) loss	(23)	60	(4)	8
Gross benefits paid	(48)	(53)	(8)	(8)
Net benefit obligation at December 31	567	615	84	91
Change in plan assets:
Fair value of plan assets at January 1	453	436	74	72
Actual return on plan assets	40	51	4	7
Employer contributions	17	19	2	2
Plan participants’ contributions	—	—	2	1
Gross benefits paid	(48)	(53)	(8)	(8)
Fair value of plan assets at December 31	462	453	74	74
Under funded status at December 31	($105)	($162)	($10)	($17)

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	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$10	$4
Current liabilities	—	(1)	(2)	(2)
Pension and other benefit obligations	(105)	(161)	(18)	(19)
Net amounts recognized at December 31	($105)	($162)	($10)	($17)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$180	$228	$13	$20
Prior service credit	(1)	(1)	—	—
	$179	$227	$13	$20

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$588	$550	$89	$85
Service cost	4	4	1	2
Interest cost	15	19	2	3
Plan participants’ contributions	—	—	2	2
Actuarial (gain) loss	(18)	55	(5)	5
Gross benefits paid	(43)	(40)	(8)	(8)
Net benefit obligation at December 31	546	588	81	89
Change in plan assets:
Fair value of plan assets at January 1	436	406	18	17
Actual return on plan assets	39	48	—	2
Employer contributions	18	22	5	5
Plan participants’ contributions	—	—	2	2
Gross benefits paid	(43)	(40)	(8)	(8)
Fair value of plan assets at December 31	450	436	17	18
Under funded status at December 31	($96)	($152)	($64)	($71)

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$3	$3
Current liabilities	—	—	(6)	(6)
Pension and other benefit obligations	(96)	(152)	(61)	(68)
Net amounts recognized at December 31	($96)	($152)	($64)	($71)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$188	$233	$18	$25
Prior service credit	(1)	(1)	(1)	(1)
	$187	$232	$17	$24

Actuarial gains related to benefit obligations in 2021 for defined benefit pension and OPEB plans were primarily due to increases in the discount rates. Actuarial losses related to benefit obligations in 2020 for defined benefit pension and OPEB plans were primarily due to decreases in the discount rates, partially offset by the impact of updated mortality projection tables.

Accumulated benefit obligations, aggregate amounts applicable to defined benefit pension and OPEB plans with accumulated benefit obligations in excess of plan assets, as well as defined benefit pension plans with projected benefit obligations in excess of plan assets as of the December 31 measurement date are as follows (in millions):

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Accumulated benefit obligations	$1,214	$1,305	$210	$227
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	1,214	1,305	210	227
Fair value of plan assets	1,011	984	106	108
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	1,251	1,351	N/A	N/A
Fair value of plan assets	1,011	984	N/A	N/A

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	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Accumulated benefit obligations	$546	$589	$84	$91
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	546	589	84	91
Fair value of plan assets	462	453	74	74
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	567	615	N/A	N/A
Fair value of plan assets	462	453	N/A	N/A

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Accumulated benefit obligations	$532	$573	$81	$89
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	532	573	81	89
Fair value of plan assets	450	436	17	18
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	546	588	N/A	N/A
Fair value of plan assets	450	436	N/A	N/A

In addition to the amounts recognized in regulatory assets in the above tables for IPL and WPL, regulatory assets were recognized for amounts associated with Corporate Services employees participating in other Alliant Energy sponsored benefit plans that were allocated to IPL and WPL at December 31 as follows (in millions):

	IPL		WPL
	2021	2020	2021	2020
Regulatory assets	$35	$44	$30	$34

Estimated Future Employer Contributions and Benefit Payments - Estimated funding for the qualified and non-qualified defined benefit pension and OPEB plans for 2022 is as follows (in millions):

	Alliant Energy	IPL	WPL
Defined benefit pension plans (a)	$2	$—	$—
OPEB plans	8	2	6

(a)Alliant Energy sponsors several non-qualified defined benefit pension plans that cover certain current and former key employees of IPL and WPL. Alliant Energy allocates pension costs to IPL and WPL for these plans. In addition, IPL and WPL amounts reflect funding for their non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.

Expected benefit payments for the qualified and non-qualified defined benefit plans, which reflect expected future service, as appropriate, are as follows (in millions):

Alliant Energy	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$85	$83	$82	$82	$83	$387
OPEB	18	17	17	17	16	71
	$103	$100	$99	$99	$99	$458

IPL	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$41	$40	$39	$39	$38	$174
OPEB	7	7	7	7	7	28
	$48	$47	$46	$46	$45	$202

WPL	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$37	$36	$35	$35	$34	$163
OPEB	7	7	7	7	6	27
	$44	$43	$42	$42	$40	$190

Investment Strategy for Plan Assets - Investment strategies for defined benefit pension and OPEB plan assets combine preservation of principal and prudent risk-taking to protect the integrity of plan assets, in order to meet the obligations to plan participants while minimizing benefit costs over the long term. Investment risk of plan assets is mitigated through diversification, including U.S. and international equity, fixed income and global asset strategies. Global asset strategies may include investments in global equity, global debt and currencies.

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Defined Benefit Pension Plan Assets - The asset mix of defined benefit pension plans is governed by allocation targets. The asset allocation is monitored regularly, and appropriate steps are taken as needed to rebalance the assets within the prescribed ranges. An overlay management service is also used to help maintain target allocations and meet liquidity needs. The overlay manager is authorized to use derivative financial instruments to facilitate this service. For separately managed accounts, prohibited investments include, but are not limited to, direct ownership of real estate, oil and gas limited partnerships, securities of the managers’ firms or affiliate firms, and Alliant Energy securities. At December 31, 2021, the current target ranges and actual allocations for the defined benefit pension plan assets were as follows:

	Target Range			Actual
	Allocation			Allocation
Cash and equivalents	0%	-	5%	3%
Equity securities - U.S.	14%	-	54%	34%
Equity securities - international	11%	-	31%	21%
Global asset securities	5%	-	15%	9%
Fixed income securities	25%	-	45%	33%

Other Postretirement Benefits Plan Assets - OPEB plan assets are comprised of specific assets within certain defined benefit pension plans (401(h) assets) as well as assets held in VEBA trusts. The investment strategy of the Corporate Services 401(h) assets mirrors those of the defined benefit pension plans, which are discussed above. For VEBA trusts with assets greater than $5 million and the WPL 401(h) assets, the mix among asset classes is governed by allocation targets. The asset allocation is monitored regularly, and appropriate steps are taken as needed to rebalance the assets within the prescribed ranges. At December 31, 2021, the current target ranges and actual allocations for VEBA trusts with assets greater than $5 million and the WPL 401(h) assets were as follows:

	Target Range			Actual
	Allocation			Allocation
Cash and equivalents	0%	-	5%	1%
Equity securities - U.S.	0%	-	55%	35%
Fixed income securities	40%	-	100%	64%

Fair Value Measurements - Fair value measurement accounting establishes three levels of fair value hierarchy that prioritize the inputs to valuation techniques used to measure fair value. Refer to Note 16 for discussion of levels within the fair value hierarchy. Level 1 items include investments in securities held in registered investment companies and directly held equity securities, which are valued at the closing price reported in the active market in which the securities are traded. Level 2 items include fixed income securities consisting of corporate and government bonds, which are valued at the closing price reported in the active market for similar assets in which the individual securities are traded or based on yields currently available on comparable securities of issuers with similar credit ratings. Certain investments that are measured at fair value using the net asset value practical expedient have not been classified in the fair value hierarchy. These fair value amounts are included below to reconcile the fair value hierarchy to the respective total plan assets.

At December 31, the fair values of qualified and non-qualified defined benefit pension plan assets were as follows (in millions):

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
Alliant Energy	Value	1	2	3	Value	1	2	3
Cash and equivalents	$35	$—	$35	$—	$46	$—	$46	$—
Equity securities - U.S.	256	256	—	—	182	182	—	—
Equity securities - international	—	—	—	—	151	151	—	—
Global asset securities	52	52	—	—	45	45	—	—
Fixed income securities	191	47	144	—	134	56	78	—
Total assets in fair value hierarchy	534	$355	$179	$—	558	$434	$124	$—
Assets measured at net asset value	477				426
Accrued investment income	1				1
Due to brokers, net (pending trades with brokers)	(1)				(1)
Total pension plan assets	$1,011				$984

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	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
IPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$16	$—	$16	$—	$21	$—	$21	$—
Equity securities - U.S.	117	117	—	—	84	84	—	—
Equity securities - international	—	—	—	—	69	69	—	—
Global asset securities	24	24	—	—	21	21	—	—
Fixed income securities	87	21	66	—	62	26	36	—
Total assets in fair value hierarchy	244	$162	$82	$—	257	$200	$57	$—
Assets measured at net asset value	218				196
Total pension plan assets	$462				$453

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
WPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$16	$—	$16	$—	$20	$—	$20	$—
Equity securities - U.S.	114	114	—	—	81	81	—	—
Equity securities - international	—	—	—	—	67	67	—	—
Global asset securities	23	23	—	—	20	20	—	—
Fixed income securities	85	21	64	—	59	25	34	—
Total assets in fair value hierarchy	238	$158	$80	$—	247	$193	$54	$—
Assets measured at net asset value	212				189
Total pension plan assets	$450				$436

At December 31, the fair values of OPEB plan assets were as follows (in millions):

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
Alliant Energy	Value	1	2	3	Value	1	2	3
Cash and equivalents	$5	$—	$5	$—	$2	$—	$2	$—
Equity securities - U.S.	11	11	—	—	4	4	—	—
Equity securities - international	—	—	—	—	3	3	—	—
Global asset securities	1	1	—	—	—	—	—	—
Fixed income securities	60	58	2	—	72	71	1	—
Total assets in fair value hierarchy	77	$70	$7	$—	81	$78	$3	$—
Assets measured at net asset value	29				27
Total OPEB plan assets	$106				$108

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
IPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$1	$—	$1	$—	$1	$—	$1	$—
Equity securities - U.S.	8	8	—	—	—	—	—	—
Fixed income securities	42	42	—	—	51	51	—	—
Total assets in fair value hierarchy	51	$50	$1	$—	52	$51	$1	$—
Assets measured at net asset value	23				22
Total OPEB plan assets	$74				$74

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
WPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$1	$—	$1	$—	$—	$—	$—	$—
Equity securities - U.S.	1	1	—	—	—	—	—	—
Fixed income securities	15	15	—	—	18	18	—	—
Total OPEB plan assets	$17	$16	$1	$—	$18	$18	$—	$—

For the various defined benefit pension and OPEB plans, Alliant Energy common stock represented less than 1% of assets directly held in the plans at December 31, 2021 and 2020.

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401(k) Savings Plans - A significant number of employees participate in defined contribution retirement plans (401(k) savings plans). Alliant Energy common stock directly held by participants represented 9% and 9% of total assets in the 401(k) savings plans at December 31, 2021 and 2020, respectively. Costs related to the 401(k) savings plans, which are partially based on the participants’ contributions and include allocated costs associated with Corporate Services employees for IPL and WPL, were as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
401(k) costs	$26	$25	$25	$13	$13	$13	$12	$12	$12

NOTE 13(b) Equity-based Compensation Plans - In 2020, Alliant Energy’s shareowners approved the 2020 OIP, which permits the grant of shares of Alliant Energy common stock, restricted stock, restricted stock units, performance shares, performance units, and other stock-based or cash-based awards to key employees. The 2020 OIP replaced the Amended and Restated 2010 OIP, which permitted similar grants. At December 31, 2021, performance shares and restricted stock units (performance- and time-vesting) were outstanding under the 2020 OIP and the Amended and Restated 2010 OIP, and 9 million shares of Alliant Energy common stock remained available for grants under the 2020 OIP. Alliant Energy satisfies share payouts related to equity awards through the issuance of new shares of its common stock. Alliant Energy also granted cash-based long-term awards, including performance units, restricted cash awards and restricted units, to certain key employees, under the DLIP. At December 31, 2021, no awards were outstanding under the DLIP. Nonvested awards generally do not have non-forfeitable rights to dividends or dividend equivalents when dividends are paid to common shareowners. A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Compensation expense	$14	$16	$26	$8	$9	$15	$6	$6	$10
Income tax benefits	4	4	7	2	2	4	2	2	3

As of December 31, 2021, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $5 million, $3 million and $2 million, respectively, which is expected to be recognized over a weighted average period of between one year and two years. Share-based compensation expense is recognized on a straight-line basis over the requisite service periods and is recorded in “Other operation and maintenance” in the income statements. As of December 31, 2021, 653,956 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

Performance Shares - Equity Awards - Payouts of 2021, 2020 and 2019 performance shares are contingent upon achievement over a three-year period of specified performance criteria, which currently is total shareowner return relative to an investor-owned utility peer group. Performance shares granted in 2021, 2020 and 2019 are to be paid out in shares of Alliant Energy common stock and are accounted for as equity awards. The fair value of each of these performance shares is based on the fair value of the underlying common stock on the grant date and the probability of satisfying the market condition contained in the agreement during a three-year performance period. The actual number of these performance shares that will be paid out upon vesting is dependent upon actual performance and may range from zero to 200% of the target number of shares. If minimum performance targets are not met during the performance period, these performance shares are forfeited. Compensation expense is recorded ratably over the performance period based on the fair value of the awards at the grant date. A summary of the 2021, 2020 and 2019 performance shares activity, with amounts representing the target number of awards, was as follows:

	2021		2020		2019
	Performance Shares - Equity	Weighted Average Grant Date Fair Value	Performance Shares - Equity	Weighted Average Grant Date Fair Value	Performance Shares - Equity	Weighted Average Grant Date Fair Value
Nonvested awards, January 1	129,156	$54.63	74,193	$47.44	—	$—
Granted	73,112	46.19	56,204	64.04	91,816	47.23
Forfeited	(5,839)	51.07	(1,241)	50.94	(17,623)	46.35
Nonvested awards, December 31	196,429	51.59	129,156	54.63	74,193	47.44

Performance Shares and Performance Units - Liability Awards - Payouts of performance shares granted prior to 2019 under the Amended and Restated 2010 OIP and performance units granted prior to 2019 under the DLIP to key employees were contingent upon achievement over three-year periods of specified performance criteria, which was total shareowner return relative to an investor-owned utility peer group. Performance shares granted prior to 2019 were able to be paid out in shares of Alliant Energy common stock, cash or a combination of cash and stock. Performance units granted prior to 2019 were paid out in cash. Alliant Energy assumed it would make future payouts of its performance shares granted prior to 2019 and performance units in cash; therefore, these performance shares and performance units were accounted for as liability awards. The fair value of each performance share and performance unit accounted for as a liability award was based on the closing market price of one share of Alliant Energy common stock at the end of the performance period. The actual payout for performance shares and performance units was dependent upon actual performance and may range from zero to 200% of the

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target number of awards. Compensation expense for these performance shares and performance units was recorded ratably over the performance period based on the fair value of the awards at each reporting period. A summary of these performance shares and performance units activity, with amounts representing the target number of awards, was as follows:

	Performance Shares (granted prior to 2019)			Performance Units (granted prior to 2019)
	2021	2020	2019	2021	2020	2019
Nonvested awards, January 1	68,307	131,872	203,188	16,801	34,574	57,761
Vested	(68,307)	(63,565)	(66,322)	(16,801)	(16,661)	(20,131)
Forfeited	—	—	(4,994)	—	(1,112)	(3,056)
Nonvested awards, December 31	—	68,307	131,872	—	16,801	34,574

Vested Awards - Certain performance shares and performance units vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows:

	Performance Shares (granted prior to 2019)			Performance Units (granted prior to 2019)
	2021	2020	2019	2021	2020	2019
	2018 Grant	2017 Grant	2016 Grant	2018 Grant	2017 Grant	2016 Grant
Performance awards vested	68,307	63,565	66,322	16,801	16,661	20,131
Percentage of target number of performance awards	172.5%	155.0%	142.5%	172.5%	155.0%	142.5%
Aggregate payout value (in millions)	$7	$6	$4	$2	$2	$1
Payout - cash (in millions)	$5	$5	$4	$2	$2	$1
Payout - common stock shares issued	13,644	9,543	6,447	N/A	N/A	N/A

Restricted Stock Units - Equity Awards - Payouts of 2021, 2020 and 2019 restricted stock units are based on the expiration of a three-year time-vesting period. Restricted stock units granted in 2021, 2020 and 2019 are to be paid out in shares of Alliant Energy common stock and are accounted for as equity awards. The fair value of each of these restricted stock units is based on the closing market price of one share of Alliant Energy common stock on the grant date of the award. Compensation expense is recorded ratably over the performance period based on the fair value of the awards on the grant date. A summary of the 2021, 2020 and 2019 restricted stock units activity was as follows:

	2021		2020		2019
	Restricted Stock Units - Equity	Weighted Average Grant Date Fair Value	Restricted Stock Units - Equity	Weighted Average Grant Date Fair Value	Restricted Stock Units - Equity	Weighted Average Grant Date Fair Value
Nonvested units, January 1	146,549	$51.54	89,281	$46.04	—	$—
Granted	80,152	48.65	61,056	59.42	105,348	45.98
Forfeited	(8,882)	49.84	(3,788)	49.01	(16,067)	45.63
Nonvested units, December 31	217,819	50.54	146,549	51.54	89,281	46.04

Restricted Stock Units - Liability Awards - Payouts of restricted stock units granted prior to 2019 were based on the expiration of a three-year time-vesting period and were able to be paid out in shares of Alliant Energy common stock, cash or a combination of cash and stock. Alliant Energy assumed it would make future payouts of its restricted stock units granted prior to 2019 in cash; therefore, restricted stock units granted prior to 2019 were accounted for as liability awards. The fair value of each restricted stock unit granted prior to 2019 was based on the closing market price of one share of Alliant Energy common stock at the end of the time-vesting period. Compensation expense was recorded ratably over the performance period based on the fair value of the awards at each reporting period. A summary of the restricted stock units granted prior to 2019 activity was as follows:

	2021	2020	2019
Nonvested units, January 1	58,550	113,033	174,163
Vested	(58,550)	(54,483)	(56,849)
Forfeited	—	—	(4,281)
Nonvested units, December 31	—	58,550	113,033

Performance Restricted Stock Units - Equity Awards - Payouts of performance restricted stock units are based upon achievement of certain performance targets during a three-year performance period, which currently includes specified growth of consolidated net income from continuing operations. The actual number of units that will be paid out upon vesting is dependent upon actual performance and may range from zero to 200% of the target number of units. If minimum performance targets are not met during the performance period, these units are forfeited. Performance restricted stock units are to be paid out in shares and are accounted for as equity awards. The fair value of each performance restricted stock unit is based on the closing market price of one share of Alliant Energy common stock on the grant date of the award. Compensation expense is recorded ratably over the performance period based on a probability assessment of payouts for the awards at each reporting period. A summary of the performance restricted stock units activity, with amounts representing the target number of units, was as follows:

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	2021		2020		2019
	Units	Weighted Average Grant Date Fair Value	Units	Weighted Average Grant Date Fair Value	Units	Weighted Average Grant Date Fair Value
Nonvested units, January 1	197,463	$47.31	206,065	$41.50	203,188	$37.23
Granted	73,112	48.66	56,204	59.37	91,816	46.10
Vested	(68,307)	38.60	(63,565)	39.12	(66,322)	33.93
Forfeited	(5,839)	50.46	(1,241)	49.25	(22,617)	44.00
Nonvested units, December 31	196,429	50.74	197,463	47.31	206,065	41.50

NOTE 13(c) Deferred Compensation Plan - Alliant Energy maintains a DCP under which key employees may defer up to 100% of base salary and short-term cash incentive compensation and directors may elect to defer all or part of their retainer and committee fees. Key employees who have made the maximum allowed contribution to the Alliant Energy 401(k) Savings Plan may receive an additional credit to the DCP. Key employees and directors may elect to have their deferrals credited to a company stock account, an interest account, equity accounts or mutual fund accounts based on certain benchmark funds.

Company Stock Account - The DCP does not permit diversification of deferrals credited to the company stock account and all distributions from participants’ company stock accounts are made in the form of shares of Alliant Energy common stock. The deferred compensation obligations for participants’ company stock accounts are recorded in “Additional paid-in capital” and the shares of Alliant Energy common stock held in a rabbi trust to satisfy this obligation are recorded in “Shares in deferred compensation trust” on Alliant Energy’s balance sheets. At December 31, the carrying value of the deferred compensation obligation for the company stock account and the shares in the deferred compensation trust based on the historical value of the shares of Alliant Energy common stock contributed to the rabbi trust, and the fair market value of the shares held in the rabbi trust, were as follows (in millions):

	2021	2020
Carrying value	$12	$11
Fair market value	24	20

Interest, Equity and Mutual Fund Accounts - Distributions from participants’ interest, equity and mutual fund accounts are in the form of cash payments. The deferred compensation obligations for participants’ interest, equity and mutual fund accounts are recorded in “Pension and other benefit obligations” on the balance sheets. At December 31, 2021 and 2020, the carrying value of Alliant Energy’s deferred compensation obligations for participants’ interest, equity and mutual fund accounts, which approximates fair market value, was $22 million and $22 million, respectively.

NOTE 14. ASSET RETIREMENT OBLIGATIONS

Recognized AROs relate to legal obligations for the removal, closure or dismantlement of several assets including, but not limited to, wind farms, ash ponds, active ash landfills, coal yards, above ground storage tanks and solar generation. Recognized AROs also include legal obligations for the management and final disposition of asbestos and polychlorinated biphenyls. AROs are recorded in “Other current liabilities” and “Other liabilities” on the balance sheets. Refer to Note 2 for information regarding regulatory assets related to AROs. A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Balance, January 1	$251	$196	$177	$134	$74	$62
Revisions in estimated cash flows	50	13	44	9	6	4
Liabilities settled	(17)	(13)	(13)	(9)	(4)	(4)
Liabilities incurred	3	48	—	38	3	10
Accretion expense	7	7	5	5	2	2
Balance, December 31	$294	$251	$213	$177	$81	$74

NOTE 15. DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Purpose - Derivative instruments are used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices, transmission congestion costs and rail transportation costs. Risk policies are maintained that govern the use of such derivative instruments. Derivative instruments were not designated as hedging instruments and included the following:

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Risk management purpose	Type of instrument
Mitigate pricing volatility for:
Fuel used to supply natural gas-fired EGUs	Natural gas swap, options and physical forward contracts (IPL and WPL)
Natural gas supplied to retail customers	Natural gas swap, options and physical forward contracts (IPL and WPL)
Fuel used at coal-fired EGUs	Coal physical forward contracts (IPL and WPL)
Optimize the value of natural gas pipeline capacity	Natural gas physical forward contracts (IPL and WPL)
	Natural gas swap contracts (IPL)
Manage transmission congestion costs	FTRs (IPL and WPL)
Manage rail transportation costs	Diesel fuel swap contracts (WPL)

Notional Amounts - As of December 31, 2021, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):

	FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	9,135	2022	191,670	2022-2030	3,193	2022-2023	3,024	2022
IPL	2,647	2022	100,560	2022-2030	1,270	2022-2023	—	—
WPL	6,488	2022	91,110	2022-2030	1,923	2022-2023	3,024	2022

Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheet as assets or liabilities. At December 31, the fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Current derivative assets	$113	$24	$48	$20	$65	$4
Non-current derivative assets	63	10	36	9	27	1
Current derivative liabilities	8	9	4	3	4	6
Non-current derivative liabilities	1	16	—	9	1	7

In 2021, Alliant Energy’s, IPL’s and WPL’s derivative assets increased and derivative liabilities decreased primarily as a result of higher natural gas prices. Based on IPL’s and WPL’s natural gas cost recovery mechanisms, this resulted in corresponding decreases in derivative regulatory assets and increases in derivative regulatory liabilities on the balance sheets.

Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At December 31, 2021 and 2020, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered.

Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at December 31, 2021 and 2020. Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement.

NOTE 16. FAIR VALUE MEASUREMENTS

Valuation Hierarchy - Fair value measurement accounting establishes three levels of fair value hierarchy that prioritize the inputs to valuation techniques used to measure fair value. Level 1 pricing inputs are quoted prices available in active markets for identical assets or liabilities as of the reporting date. Level 2 pricing inputs are quoted prices for similar assets or liabilities in active markets or quoted prices for identical or similar assets or liabilities in markets that are not active as of the reporting date. Level 3 pricing inputs are unobservable inputs for assets or liabilities for which little or no market data exist and require significant management judgment or estimation.

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The fair value hierarchy gives the highest priority to quoted prices in active markets (Level 1) and the lowest priority to unobservable data (Level 3). In some cases, the inputs used to measure fair value might fall in different levels of the fair value hierarchy. The lowest level input that is significant to a fair value measurement in its entirety determines the applicable level in the fair value hierarchy. Assessing the significance of a particular input to the fair value measurement in its entirety requires judgment, considering factors specific to the asset or liability.

Valuation Techniques -

Derivative assets and derivative liabilities - Swap, option and physical forward commodity contracts were non-exchange-based derivative instruments and were valued using indicative price quotations from a pricing vendor that provides daily exchange forward price settlements, from broker or dealer quotations, from market publications or from on-line exchanges. The indicative price quotations reflected the average of the bid-ask mid-point prices and were obtained from sources believed to provide the most liquid market for the commodity. A portion of these indicative price quotations were corroborated using quoted prices for similar assets or liabilities in active markets and categorized derivative instruments based on such indicative price quotations as Level 2. Commodity contracts that were valued using indicative price quotations based on significant assumptions such as seasonal or monthly shaping and indicative price quotations that could not be readily corroborated were categorized as Level 3. Swap, option and physical forward commodity contracts were predominately at liquid trading points. FTRs were valued using auction prices and were categorized as Level 3. Refer to Note 15 for additional details of derivative assets and derivative liabilities.

Deferred proceeds (sales of receivables) - The fair value of IPL’s deferred proceeds related to its sales of accounts receivable program was calculated each reporting date using the cost approach valuation technique. The fair value represents the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold due to the short-term nature of the collection period. These inputs were considered unobservable and deferred proceeds were categorized as Level 3. Deferred proceeds represent IPL’s maximum exposure to loss related to the receivables sold. Refer to Note 5(b) for additional information regarding deferred proceeds.

Long-term debt (including current maturities) - The fair value of long-term debt instruments was based on a discounted cash flow methodology using observable data from comparably traded securities with similar credit profiles, and was substantially classified as Level 2. Refer to Note 9(b) for additional information regarding long-term debt.

Fair Value of Financial Instruments - The carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. Carrying amounts and the related estimated fair values of other financial instruments at December 31 were as follows (in millions):

Alliant Energy	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Money market fund investments	$32	$32	$—	$—	$32	$44	$44	$—	$—	$44
Derivatives	176	—	146	30	176	34	—	5	29	34
Deferred proceeds	214	—	—	214	214	188	—	—	188	188
Liabilities and equity:
Derivatives	9	—	8	1	9	25	—	25	—	25
Long-term debt (incl. current maturities)	7,368	—	8,329	1	8,330	6,777	—	8,107	2	8,109

IPL	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Money market fund investments	$32	$32	$—	$—	$32	$44	$44	$—	$—	$44
Derivatives	84	—	65	19	84	29	—	3	26	29
Deferred proceeds	214	—	—	214	214	188	—	—	188	188
Liabilities and equity:
Derivatives	4	—	3	1	4	12	—	12	—	12
Long-term debt	3,643	—	4,124	—	4,124	3,345	—	4,021	—	4,021

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WPL	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Derivatives	$92	$—	$81	$11	$92	$5	$—	$2	$3	$5
Liabilities and equity:
Derivatives	5	—	5	—	5	13	—	13	—	13
Long-term debt (incl. current maturities)	2,429	—	2,862	—	2,862	2,130	—	2,690	—	2,690

Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions):

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
	2021	2020	2021	2020
Beginning balance, January 1	$29	$21	$188	$188
Total net gains included in changes in net assets (realized/unrealized)	6	11	—	—
Purchases	21	14	—	—
Sales	(1)	(1)	—	—
Settlements (a)	(26)	(16)	26	—
Ending balance, December 31	$29	$29	$214	$188
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at December 31	$6	$11	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
	2021	2020	2021	2020
Beginning balance, January 1	$26	$18	$188	$188
Total net gains (losses) included in changes in net assets (realized/unrealized)	(3)	10	—	—
Purchases	16	11	—	—
Sales	(1)	(1)	—	—
Settlements (a)	(20)	(12)	26	—
Ending balance, December 31	$18	$26	$214	$188
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at December 31	($3)	$10	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
	2021	2020
Beginning balance, January 1	$3	$3
Total net gains included in changes in net assets (realized/unrealized)	9	1
Purchases	5	3
Settlements	(6)	(4)
Ending balance, December 31	$11	$3
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at December 31	$9	$1

(a)Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold.

Commodity Contracts - The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets at December 31 as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
2021	$9	$20	$8	$10	$1	$10
2020	18	11	17	9	1	2

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NOTE 17. COMMITMENTS AND CONTINGENCIES

NOTE 17(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects, including WPL’s expansion of solar generation. At December 31, 2021, Alliant Energy’s and WPL’s minimum future commitments in 2022 for these projects were $178 million and $177 million, respectively.

NOTE 17(b) Other Purchase Commitments - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase commitments associated with other goods and services. At December 31, 2021, the related minimum future commitments were as follows (in millions):

Alliant Energy	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$307	$196	$144	$102	$88	$175	$1,012
Coal	63	46	25	3	—	—	137
Other (a)	82	14	8	5	2	25	136
	$452	$256	$177	$110	$90	$200	$1,285

IPL	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$148	$108	$84	$52	$42	$65	$499
Coal	32	27	17	3	—	—	79
Other (a)	34	4	2	2	2	23	67
	$214	$139	$103	$57	$44	$88	$645

WPL	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$159	$88	$60	$50	$46	$110	$513
Coal	31	19	8	—	—	—	58
Other (a)	33	1	1	1	1	—	37
	$223	$108	$69	$51	$47	$110	$608

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at December 31, 2021.

NOTE 17(c) Legal Proceedings - Alliant Energy, IPL and WPL are involved in legal and administrative proceedings before various courts and agencies with respect to matters arising in the ordinary course of business. Although unable to predict the outcome of these matters, Alliant Energy, IPL and WPL believe that appropriate reserves have been established and final disposition of these actions will not have a material effect on their financial condition or results of operations.

NOTE 17(d) Guarantees and Indemnifications -

Whiting Petroleum - Whiting Petroleum is an independent oil and gas company. In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee the partnership obligations of an affiliate of Whiting Petroleum under multiple general partnership agreements in the oil and gas industry. The guarantees do not include a maximum limit. Based on information made available to Alliant Energy by Whiting Petroleum, the Whiting Petroleum affiliate holds an approximate 6% share in the partnerships, and currently known obligations include costs associated with the future abandonment of certain facilities owned by the partnerships. The general partnerships were formed under California law, and Alliant Energy Resources, LLC may need to perform under the guarantees if the affiliate of Whiting Petroleum is unable to meet its partnership obligations.

As of December 31, 2021, the currently known partnership obligations for the abandonment obligations are estimated at $60 million, which represents Alliant Energy’s currently estimated maximum exposure under the guarantees. Alliant Energy estimates its expected loss to be a portion of the $60 million of known partnership abandonment obligations of the Whiting Petroleum affiliate and the other partners. Alliant Energy is not aware of any material liabilities related to these guarantees that it is probable that it will be obligated to pay; however, as of both December 31, 2021 and 2020, a liability of $5 million is recorded in “Other liabilities” on Alliant Energy’s balance sheets for expected credit losses related to the contingent obligations that are in the scope of these guarantees.

Non-utility Wind Farm in Oklahoma - In 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third-party under a long-term PPA. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and PPA. Alliant Energy’s obligations under the operating agreement were $67 million as of December 31, 2021 and will reduce annually until expiring in July 2047. Alliant Energy’s obligations under the PPA are subject to a maximum limit of $17 million and expire in December 2031, subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of December 31, 2021 and 2020.

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NOTE 17(e) Environmental Matters - Alliant Energy, IPL and WPL are subject to environmental regulations as a result of their current and past operations. These regulations are designed to protect public health and the environment and have resulted in compliance, remediation, containment and monitoring obligations, which are recorded as current and non-current environmental liabilities. Substantially all of the environmental liabilities recorded on the balance sheets relate to MGP sites.

Manufactured Gas Plant Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At December 31, 2021, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At December 31, 2021, such amounts for WPL were not material.

	Alliant Energy			IPL
Range of estimated future costs	$8	-	$24	$6	-	$18
Current and non-current environmental liabilities	11			8

IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential CAA issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include fuel switching or retiring Prairie Creek Units 1 and 3 by December 31, 2025. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers.

Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however future capital investments and/or modifications to EGUs and electric and gas distribution systems to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Effluent Limitation Guidelines, CCR Rule, and various legislation and EPA regulations to monitor and regulate the emission of GHG, including the CAA.

NOTE 17(f) Credit Risk - IPL provides retail electric and gas services in Iowa and wholesale electric service in Minnesota, Illinois and Iowa. WPL provides retail electric and gas services and wholesale electric service in Wisconsin. The geographic concentration of IPL’s and WPL’s customers did not contribute significantly to overall credit risk exposure. In addition, as a result of a diverse customer base, IPL and WPL did not have any significant credit risk concentration for receivables arising from the sale of electricity or gas services.

Alliant Energy, IPL and WPL are subject to credit risk related to the ability of counterparties to meet their contractual payment obligations or the potential non-performance of counterparties to deliver contracted commodities and other goods or services at the contracted price. Credit policies are maintained to mitigate credit risk. These credit policies include evaluation of the financial condition of certain counterparties, use of credit risk-related contingent provisions in certain agreements that require credit support from counterparties not meeting specific criteria, diversification of counterparties to reduce concentrations of credit risk and the use of standardized agreements that facilitate the netting of cash flows associated with certain counterparties. Based on these credit policies and counterparty diversification, as well as utility cost recovery mechanisms, it is unlikely that counterparty non-performance would have a material effect on financial condition or results of operations. However, there is no assurance that these items will protect against all losses from counterparty non-performance.

Refer to Notes 5(a) and 15 for details of allowances for expected credit losses and credit risk-related contingent features, respectively.

NOTE 17(g) Collective Bargaining Agreements - At December 31, 2021, employees covered by collective bargaining agreements represented 54%, 69% and 83% of total employees of Alliant Energy, IPL and WPL, respectively. In May 2022, WPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 965 expires, representing 26% and 83% of total employees of Alliant Energy and WPL, respectively.

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NOTE 18. SEGMENTS OF BUSINESS

Alliant Energy - Alliant Energy’s principal businesses as of December 31, 2021 are:

•Utility - includes the operations of IPL and WPL, which primarily serve retail customers in Iowa and Wisconsin. The utility business has three reportable segments: a) utility electric operations; b) utility gas operations; and c) utility other, which includes steam operations and the unallocated portions of the utility business. Various line items in the following tables are not allocated to the electric and gas segments for management reporting purposes, and therefore, are included only in “Total Utility.”

•ATC Holdings, Non-utility, Parent and Other - includes the operations of AEF and its subsidiaries, Corporate Services, the Alliant Energy parent company, and any Alliant Energy parent company consolidating adjustments. AEF is comprised of Alliant Energy’s interest in ATC Holdings, Travero, a non-utility wind farm, corporate venture investments, the Sheboygan Falls Energy Facility and other non-utility holdings.

Alliant Energy’s administrative support services are directly charged to the applicable segment where practicable. In all other cases, administrative support services are allocated to the applicable segment based on services agreements. Intersegment revenues were not material to Alliant Energy’s operations and there was no single customer whose revenues were 10% or more of Alliant Energy’s consolidated revenues. All of Alliant Energy’s operations and assets are located in the U.S. Certain financial information relating to Alliant Energy’s business segments, which represent the services provided to its customers, was as follows (in millions):

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2021	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$3,081	$456	$49	$3,586	$83	$3,669
Depreciation and amortization	591	54	6	651	6	657
Operating income (loss)	716	63	(11)	768	27	795
Interest expense				244	33	277
Equity income from unconsolidated investments, net	(2)	—	—	(2)	(60)	(62)
Income tax expense (benefit)				(87)	13	(74)
Net income attributable to Alliant Energy common shareowners				618	41	659
Total assets	14,924	1,487	1,103	17,514	1,039	18,553
Investments in equity method subsidiaries	17	—	—	17	491	508
Construction and acquisition expenditures	980	90	—	1,070	99	1,169

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2020	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$2,920	$373	$49	$3,342	$74	$3,416
Depreciation and amortization	556	49	5	610	5	615
Operating income (loss)	643	74	(1)	716	24	740
Interest expense				243	32	275
Equity income from unconsolidated investments, net	(2)	—	—	(2)	(59)	(61)
Income tax expense (benefit)				(66)	9	(57)
Net income attributable to Alliant Energy common shareowners				573	41	614
Total assets	14,358	1,413	990	16,761	949	17,710
Investments in equity method subsidiaries	11	—	—	11	465	476
Construction and acquisition expenditures	1,109	182	2	1,293	73	1,366

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2019	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$3,064	$455	$46	$3,565	$83	$3,648
Depreciation and amortization	513	47	3	563	4	567
Operating income	679	70	1	750	28	778
Interest expense				229	44	273
Equity income from unconsolidated investments, net	(1)	—	—	(1)	(52)	(53)
Income tax expense (benefit)				73	(4)	69
Net income attributable to Alliant Energy common shareowners				517	40	557
Total assets	13,659	1,269	856	15,784	917	16,701
Investments in equity method subsidiaries	9	—	—	9	449	458
Construction and acquisition expenditures	1,439	100	—	1,539	101	1,640

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IPL - IPL is a utility primarily serving retail customers in Iowa and includes three reportable segments: a) electric operations; b) gas operations; and c) other, which includes steam operations and the unallocated portions of the utility business. Various line items in the following tables are not allocated to the electric and gas segments for management reporting purposes, and therefore, are included only in “Total.” Intersegment revenues were not material to IPL’s operations and there was no single customer whose revenues were 10% or more of IPL’s consolidated revenues. All of IPL’s operations and assets are located in the U.S. Certain financial information relating to IPL’s business segments, which represent the services provided to its customers, was as follows (in millions):

2021	Electric	Gas	Other	Total
Revenues	$1,752	$265	$46	$2,063
Depreciation and amortization	338	31	6	375
Operating income (loss)	420	43	(3)	460
Interest expense				139
Income tax benefit				(36)
Net income available for common stock				350
Total assets	8,602	819	575	9,996
Construction and acquisition expenditures	342	42	—	384

2020	Electric	Gas	Other	Total
Revenues	$1,695	$208	$44	$1,947
Depreciation and amortization	321	30	5	356
Operating income	358	50	2	410
Interest expense				139
Income tax benefit				(47)
Net income available for common stock				324
Total assets	8,518	766	565	9,849
Construction and acquisition expenditures	626	59	2	687

2019	Electric	Gas	Other	Total
Revenues	$1,781	$264	$44	$2,089
Depreciation and amortization	295	29	3	327
Operating income	360	39	4	403
Interest expense				127
Income taxes				24
Net income available for common stock				284
Total assets	8,075	734	468	9,277
Construction and acquisition expenditures	964	56	—	1,020

WPL - WPL is a utility serving customers in Wisconsin and includes three reportable segments: a) electric operations; b) gas operations; and c) other, which includes the unallocated portions of the utility business. Various line items in the following tables are not allocated to the electric and gas segments for management reporting purposes, and therefore, are included only in “Total.” Intersegment revenues were not material to WPL’s operations and there was no single customer whose revenues were 10% or more of WPL’s consolidated revenues. All of WPL’s operations and assets are located in the U.S. Certain financial information relating to WPL’s business segments, which represent the services provided to its customers, was as follows (in millions):

2021	Electric	Gas	Other	Total
Revenues	$1,329	$191	$3	$1,523
Depreciation and amortization	253	23	—	276
Operating income (loss)	296	20	(8)	308
Interest expense				105
Income tax benefit				(51)
Net income				268
Total assets	6,322	668	528	7,518
Construction and acquisition expenditures	638	48	—	686

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2020	Electric	Gas	Other	Total
Revenues	$1,225	$165	$5	$1,395
Depreciation and amortization	235	19	—	254
Operating income (loss)	285	24	(3)	306
Interest expense				104
Income tax benefit				(19)
Net income				249
Total assets	5,840	647	425	6,912
Construction and acquisition expenditures	483	123	—	606

2019	Electric	Gas	Other	Total
Revenues	$1,283	$191	$2	$1,476
Depreciation and amortization	218	18	—	236
Operating income (loss)	319	31	(3)	347
Interest expense				102
Income taxes				49
Net income				233
Total assets	5,584	535	388	6,507
Construction and acquisition expenditures	475	44	—	519

NOTE 19. RELATED PARTIES

Service Agreements - Pursuant to service agreements, IPL and WPL receive various administrative and general services from an affiliate, Corporate Services. These services are billed to IPL and WPL at cost based on expenses incurred by Corporate Services for the benefit of IPL and WPL, respectively. These costs consisted primarily of employee compensation and benefits, fees associated with various professional services, depreciation and amortization of property, plant and equipment, and a return on net assets. Corporate Services also acts as agent on behalf of IPL and WPL pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases among IPL and WPL based on statements received from MISO. The amounts billed for services provided, sales credited and purchases were as follows (in millions):

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Corporate Services billings	$180	$176	$185	$154	$142	$142
Sales credited	22	35	68	23	3	7
Purchases billed	441	329	331	116	108	120

As of December 31, net intercompany payables to Corporate Services were as follows (in millions):

	2021	2020
IPL	$110	$110
WPL	83	73

ATC - Pursuant to various agreements, WPL receives a range of transmission services from ATC. WPL provides operation, maintenance, and construction services to ATC. WPL and ATC also bill each other for use of shared facilities owned by each party. The related amounts billed between the parties were as follows (in millions):

	2021	2020	2019
ATC billings to WPL	$122	$108	$109
WPL billings to ATC	18	10	13

As of December 31, 2021 and 2020, WPL owed ATC net amounts of $10 million and $9 million, respectively.

In 2020, WPL received $46 million from ATC related to construction deposits WPL previously provided ATC for transmission network upgrades for West Riverside, which is substantially recorded in “Other” in Alliant Energy’s and WPL’s cash flows from investing activities.

WPL’s Sheboygan Falls Energy Facility Lease - Refer to Note 10 for discussion of WPL’s Sheboygan Falls Energy Facility lease.

ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE

None.

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ITEM 9A. CONTROLS AND PROCEDURES

Alliant Energy’s, IPL’s and WPL’s management evaluated, with the participation of each of Alliant Energy’s, IPL’s and WPL’s Chief Executive Officer, Chief Financial Officer and Disclosure Committee, the effectiveness of the design and operation of Alliant Energy’s, IPL’s and WPL’s disclosure controls and procedures as of the end of the quarter ended December 31, 2021 pursuant to the requirements of the Securities Exchange Act of 1934, as amended. Based on their evaluation, the Chief Executive Officer and the Chief Financial Officer concluded that Alliant Energy’s, IPL’s and WPL’s disclosure controls and procedures were effective as of the end of the quarter ended December 31, 2021.

There was no change in Alliant Energy’s, IPL’s and WPL’s internal control over financial reporting that occurred during the quarter ended December 31, 2021 that has materially affected, or is reasonably likely to materially affect, Alliant Energy’s, IPL’s and WPL’s internal control over financial reporting.

Management’s Annual Report on Internal Control over Financial Reporting - The management of Alliant Energy, IPL and WPL are responsible for establishing and maintaining adequate internal control over financial reporting, as such term is defined in Rules 13a-15(f) and 15d-15(f) under the Securities Exchange Act of 1934. Alliant Energy’s, IPL’s and WPL’s internal control over financial reporting is designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with GAAP.

Because of the inherent limitations of internal control over financial reporting, misstatements may not be prevented or detected on a timely basis. Also, projections of any evaluation of the effectiveness of the internal control over financial reporting to future periods are subject to the risk that the controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Alliant Energy’s, IPL’s and WPL’s management assessed the effectiveness of their respective internal control over financial reporting as of December 31, 2021 using the criteria set forth in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission. Based on these assessments, Alliant Energy’s, IPL’s and WPL’s management concluded that, as of December 31, 2021, their respective internal control over financial reporting was effective.

Deloitte & Touche LLP, Alliant Energy’s independent registered public accounting firm, has audited Alliant Energy’s internal control over financial reporting. That report is included herein. This report does not include an attestation report of IPL’s and WPL’s independent registered public accounting firm regarding its assessment of IPL’s and WPL’s internal control over financial reporting.

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REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Shareowners and the Board of Directors of Alliant Energy Corporation:

Opinion on Internal Control over Financial Reporting

We have audited the internal control over financial reporting of Alliant Energy Corporation and subsidiaries (the “Company”) as of December 31, 2021, based on criteria established in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO). In our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2021, based on criteria established in Internal Control - Integrated Framework (2013) issued by COSO.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the consolidated financial statements as of and for the year ended December 31, 2021, of the Company and our report dated February 18, 2022, expressed an unqualified opinion on those financial statements.

Basis for Opinion

The Company’s management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting, included in the accompanying Management’s Annual Report on Internal Control over Financial Reporting. Our responsibility is to express an opinion on the Company’s internal control over financial reporting based on our audit. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audit in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on the assessed risk, and performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

Definition and Limitations of Internal Control over Financial Reporting

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

/s/ DELOITTE & TOUCHE LLP

Milwaukee, Wisconsin

February 18, 2022

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ITEM 9B. OTHER INFORMATION

None.

ITEM 9C. DISCLOSURE REGARDING FOREIGN JURISDICTIONS THAT PREVENT INSPECTIONS

None.

PART III

ITEM 10. DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE

The directors of Alliant Energy, IPL and WPL are the same, and therefore, the information required by Item 10 relating to directors and nominees for election of directors is the same for all registrants. The information required by Item 10 relating to directors and nominees for election of directors at the 2022 Annual Meeting of Shareowners, the timely filing of reports under Section 16 of the Securities Exchange Act of 1934, audit committees and audit committee financial experts, and Alliant Energy’s, IPL’s and WPL’s Code of Conduct is incorporated herein by reference to the relevant information in the 2022 Alliant Energy Proxy Statement, which will be filed with the SEC within 120 days after the end of Alliant Energy’s, IPL’s and WPL’s fiscal years. The code of ethics, also referred to as the Code of Conduct, of Alliant Energy, IPL and WPL are the same. Information regarding executive officers of Alliant Energy, IPL and WPL may be found in Part I of this report under the caption “Information About Executive Officers.”

ITEM 11. EXECUTIVE COMPENSATION

The directors and executive officers of Alliant Energy, IPL and WPL for which compensation information must be included are the same. Therefore, the information required by Item 11 for each of Alliant Energy, IPL and WPL is incorporated herein by reference to the relevant information in the 2022 Alliant Energy Proxy Statement, which will be filed with the SEC within 120 days after the end of Alliant Energy’s, IPL’s and WPL’s fiscal years.

ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS

Information regarding Alliant Energy’s equity compensation plans as of December 31, 2021 was as follows:

	(A)		(C)
	Number of securities to be	(B)	Number of securities remaining available
	issued upon exercise of	Weighted-average exercise	for future issuance under equity
	outstanding options,	price of outstanding options,	compensation plans (excluding
Plan Category	warrants and rights	warrants and rights	securities reflected in column (A))
Equity compensation plans approved by shareowners	365,362 (a)	$47.85	8,626,914 (b)
Equity compensation plans not approved by shareowners (c)	N/A	N/A	N/A (d)
	365,362	$47.85	8,626,914

(a)Represents performance shares, performance restricted stock units and restricted stock units granted under the 2020 OIP. Performance restricted stock units and performance shares are paid out in shares of Alliant Energy’s common stock. The performance share and performance restricted stock unit awards are adjusted by a performance multiplier, which ranges from zero to 200%, based on the performance criteria. The performance share and performance restricted stock unit awards included in column (A) of the table reflect an assumed payout in the form of Alliant Energy’s common stock at the maximum performance multiplier of 200%. Also included are restricted stock units granted under the 2020 OIP, which are paid out in shares of Alliant Energy’s common stock at the expiration of a three-year time-vesting period.

(b)All of the available shares under the 2020 OIP may be issued as awards in the form of shares of Alliant Energy’s common stock, restricted stock, restricted stock units, performance shares, performance units and other stock-based or cash-based awards. As of December 31, 2021, there were performance shares and restricted stock units (performance- and time-vesting) outstanding under the 2020 OIP.

(c)As of December 31, 2021, there were 383,532 shares of Alliant Energy’s common stock held under the DCP, which is described in Note 13(c).

(d)There is no limit on the number of shares of Alliant Energy’s common stock that may be held under the DCP.

The remainder of the information required by Item 12 for Alliant Energy, and the information required by Item 12 for each of IPL and WPL, is incorporated herein by reference to the relevant information in the 2022 Alliant Energy Proxy Statement, which will be filed with the SEC within 120 days after the end of Alliant Energy’s, IPL’s and WPL’s fiscal year.

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ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE

The information required by Item 13 for each of Alliant Energy, IPL and WPL is incorporated herein by reference to the relevant information in the 2022 Alliant Energy Proxy Statement, which will be filed with the SEC within 120 days after the end of Alliant Energy’s, IPL’s and WPL’s fiscal years.

ITEM 14. PRINCIPAL ACCOUNTING FEES AND SERVICES

ALLIANT ENERGY

The information required by Item 14 is incorporated herein by reference to the relevant information in the 2022 Alliant Energy Proxy Statement, which will be filed with the SEC within 120 days after the end of Alliant Energy’s fiscal year.

IPL AND WPL

Each of IPL’s and WPL’s Audit Committee of the Board of Directors has adopted a policy that requires advance approval of all audit, audit-related, tax and other permitted services performed by the independent registered public accounting firm. The policy provides for pre-approval by the Audit Committee of specifically defined audit and non-audit services after the Audit Committee is provided with the appropriate level of details regarding the specific services to be provided. The policy does not permit delegation of the Audit Committee’s authority to management. In the event the need for specific services arises between Audit Committee meetings, the Audit Committee has delegated to the Chairperson of the Audit Committee authority to approve permitted services provided that the Chairperson reports any decisions to the Audit Committee at its next scheduled meeting. The principal accounting fees billed to Alliant Energy by its independent registered public accounting firm, all of which were approved in advance by the Audit Committee, directly related and allocated to IPL and WPL were as follows (in thousands):

	IPL				WPL
	2021		2020		2021		2020
	Fees	% of Total	Fees	% of Total	Fees	% of Total	Fees	% of Total
Audit fees	$1,367	96%	$1,331	96%	$1,005	90%	$947	89%
Audit-related fees	49	4%	51	4%	85	8%	39	4%
Tax fees	3	—%	4	—%	18	2%	78	7%
All other fees	4	—%	3	—%	3	—%	2	—%
	$1,423	100%	$1,389	100%	$1,111	100%	$1,066	100%

IPL’s and WPL’s audit fees for 2021 and 2020 consisted of the respective fees billed for the audits of the financial statements of IPL and its subsidiaries and WPL and its subsidiary, for reviews of financial statements included in Form 10-Q filings, and for services normally provided in connection with statutory and regulatory filings, such as financing transactions. IPL’s and WPL’s audit fees also included their respective portion of fees for the 2021 and 2020 audits of Alliant Energy’s financial statements and effectiveness of internal controls over financial reporting. IPL’s and WPL’s audit-related fees for 2021 and 2020 consisted of the fees billed for services rendered related to employee benefits plan audits and other attest services. IPL’s and WPL’s tax fees for 2021 and 2020 consisted of the fees billed for professional services rendered for tax compliance, tax advice and tax planning, including all services performed by the tax professional staff of affiliates of the independent registered public accounting firm, except those rendered in connection with the audit. All other fees for 2021 and 2020 for IPL and WPL consisted of license fees for accounting research software products and virtual seminars. The Audit Committee does not consider the provision of non-audit services by the independent registered public accounting firm described above to be incompatible with maintaining independence of the independent registered public accounting firm.

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PART IV

ITEM 15. EXHIBITS, FINANCIAL STATEMENT SCHEDULES

(1)Consolidated Financial Statements - Refer to Item 8 Financial Statements and Supplementary Data for Alliant Energy’s, IPL’s and WPL’s financial statements and Reports of Independent Registered Public Accounting Firm (Public Company Accounting Oversight Board ID No. 34).

(2)Financial Statement Schedules -

SCHEDULE I - CONDENSED PARENT COMPANY FINANCIAL STATEMENTS

ALLIANT ENERGY CORPORATION (Parent Company Only)	Year Ended December 31,
CONDENSED STATEMENTS OF INCOME	2021	2020	2019
	(in millions)
Operating expenses	$5	$7	$2
Operating loss	(5)	(7)	(2)
Other (income) and deductions:
Equity earnings from consolidated subsidiaries	(664)	(625)	(562)
Interest expense	1	2	9
Other	1	4	7
Total other (income) and deductions	(662)	(619)	(546)
Income before income taxes	657	612	544
Income tax benefit	(5)	(4)	(15)
Net income	$662	$616	$559

Refer to accompanying Notes to Condensed Financial Statements.

ALLIANT ENERGY CORPORATION (Parent Company Only)	December 31,
CONDENSED BALANCE SHEETS	2021	2020
	(in millions)
ASSETS
Current assets:
Notes receivable from affiliated companies	$16	$32
Other	5	5
Total current assets	21	37
Investments:
Investments in consolidated subsidiaries	7,061	6,664
Other	2	2
Total investments	7,063	6,666
Other assets	96	88
Total assets	$7,180	$6,791

LIABILITIES AND EQUITY
Current liabilities:
Commercial paper	$279	$132
Notes payable to affiliated companies	900	937
Other	4	29
Total current liabilities	1,183	1,098
Other liabilities	2	2
Common equity:
Common stock and additional paid-in capital	2,752	2,706
Retained earnings	3,255	2,996
Shares in deferred compensation trust	(12)	(11)
Total common equity	5,995	5,691
Total liabilities and equity	$7,180	$6,791

Refer to accompanying Notes to Condensed Financial Statements.

99

ALLIANT ENERGY CORPORATION (Parent Company Only)	Year Ended December 31,
CONDENSED STATEMENTS OF CASH FLOWS	2021	2020	2019
	(in millions)
Net cash flows from operating activities	$494	$396	$305
Cash flows used for investing activities:
Capital contributions to consolidated subsidiaries	(295)	(429)	(250)
Net change in notes receivable from and payable to affiliates	(21)	201	8
Dividends from consolidated subsidiaries in excess of equity earnings	50	—	—
Net cash flows used for investing activities	(266)	(228)	(242)
Cash flows used for financing activities:
Common stock dividends	(403)	(377)	(338)
Proceeds from issuance of common stock, net	28	247	390
Net change in commercial paper	147	(37)	(116)
Other	—	(1)	1
Net cash flows used for financing activities	(228)	(168)	(63)
Net increase (decrease) in cash, cash equivalents and restricted cash	—	—	—
Cash, cash equivalents and restricted cash at beginning of period	—	—	—
Cash, cash equivalents and restricted cash at end of period	$—	$—	$—
Supplemental cash flows information:
Cash (paid) refunded during the period for:
Interest	($1)	($2)	($9)
Income taxes, net	4	10	14

Refer to accompanying Notes to Condensed Financial Statements.

ALLIANT ENERGY CORPORATION (Parent Company Only)

NOTES TO CONDENSED FINANCIAL STATEMENTS

Pursuant to rules and regulations of the SEC, the Condensed Financial Statements of Alliant Energy Corporation (Parent Company Only) do not reflect all of the information and notes normally included with financial statements prepared in accordance with GAAP. Therefore, these Condensed Financial Statements should be read in conjunction with the Financial Statements and related Notes included in the combined 2021 Form 10-K, Part II, Item 8, which is incorporated herein by reference.

In the Condensed Financial Statements of Alliant Energy Corporation (Parent Company Only), investments in subsidiaries are accounted for using the equity method.

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES

		Additions
	Balance,	Charged to	Charged to Other		Balance,
Description	January 1	Expense	Accounts (a)	Deductions (b)	December 31
	(in millions)

Valuation and Qualifying Accounts Which are Deducted in the Balance Sheet from the Assets to Which They Apply:

Accumulated Provision for Uncollectible Accounts:
	Alliant Energy (c)
		Year ended December 31, 2021	$18	$12	$—	$19	$11
		Year ended December 31, 2020	7	25	9	23	18
		Year ended December 31, 2019	10	17	2	22	7
	IPL (c)
		Year ended December 31, 2021	$1	$6	$—	$6	$1
		Year ended December 31, 2020	1	18	—	18	1
		Year ended December 31, 2019	3	16	—	18	1
	WPL
		Year ended December 31, 2021	$17	$6	$—	$13	$10
		Year ended December 31, 2020	6	7	9	5	17
		Year ended December 31, 2019	7	1	2	4	6

Note: The above provisions relate to various customer, notes and other receivable balances included in various line items on the respective balance sheets.

100

(a)Accumulated provision for uncollectible accounts: In accordance with its regulatory treatment, certain amounts provided by WPL are recorded in regulatory assets.

(b)Deductions are of the nature for which the reserves were created. In the case of the accumulated provision for uncollectible accounts, deductions from this reserve are reduced by recoveries of amounts previously written off.

(c)Refer to Note 5(b) for discussion of IPL’s sales of accounts receivable program.

NOTE: All other schedules are omitted because they are not applicable or not required, or because that required information is shown either in the financial statements or in the notes thereto.

(3)    Exhibits Required by SEC Regulation S-K - Pursuant to Item 601(b)(4)(iii) of Regulation S-K, the registrants agree to furnish to the SEC, upon request, any instrument defining the rights of holders of unregistered long-term debt not filed as an exhibit to this combined Form 10-K. No such instrument authorizes securities in excess of 10% of the total assets of Alliant Energy, IPL or WPL, as the case may be. The following exhibits for Alliant Energy, IPL and WPL are filed herewith or incorporated herein by reference.

Exhibit Number	Description
3.1	Restated Articles of Incorporation of Alliant Energy, as amended (incorporated by reference to Exhibit 4.1 to Alliant Energy’s Registration Statement on Form S-8 (Reg. No. 333-117654))
3.1a	Articles of Amendment to Restated Articles of Incorporation of Alliant Energy, as amended, effective May 4, 2016 (incorporated by reference to Exhibit 3.1 to Alliant Energy’s Form 10-Q for the quarter ended March 31, 2016 (File No. 1-9894))
3.2	Amended and Restated Bylaws of Alliant Energy, effective September 23, 2021 (incorporated by reference to Exhibit 3.1 to Alliant Energy’s Form 8-K, filed September 24, 2021 (File No. 1-9894))
3.3	Amended and Restated Articles of Incorporation of WPL, effective May 9, 2013 (incorporated by reference to Exhibit 3.4 to WPL’s Form 8-K, filed May 13, 2013 (File No. 0-337))
3.4	Amended and Restated Bylaws of WPL, effective October 27, 2020 (incorporated by reference to Exhibit 3.3 to WPL’s Form 8-K, filed October 29, 2020 (File No. 0-337))
3.5	Amended and Restated Articles of Incorporation of IPL, effective December 20, 2021 (incorporated by reference to Exhibit 3.1 to IPL’s Form 8-K, filed December 21, 2021 (File No. 1-4117))
3.6	Amended and Restated Bylaws of IPL, effective October 27, 2020 (incorporated by reference to Exhibit 3.2 to IPL’s Form 8-K, filed October 29, 2020 (File No. 1-4117))
4.1	Amended and Restated Five-Year Master Credit Agreement, effective December 17, 2021, among Alliant Energy, IPL, WPL, Wells Fargo Bank, National Association (N.A.) and the lender parties set forth therein (incorporated by reference to Exhibit 4.1 to Alliant Energy’s Form 8-K, filed December 21, 2021 (File No. 1-9894))
4.2	Senior Note Indenture, dated as of September 30, 2009, between Alliant Energy and Wells Fargo Bank, N.A. (incorporated by reference to Exhibit 4.28 to Alliant Energy’s Registration Statement on Form S-3 (Reg. No. 333-162214))
4.3	Indenture, dated as of June 12, 2018, among AEF, Alliant Energy, as guarantor, and The Bank of New York Mellon Trust Company, N.A., as trustee (incorporated by reference to Exhibit 4.1 to Alliant Energy’s Form 8-K, filed June 12, 2018 (File No. 1-9894))
4.4	Indenture, dated as of November 20, 2020, among AEF, Alliant Energy as guarantor, and The Bank of New York Mellon Trust Company, N.A., as trustee (incorporated by reference to Exhibit 4.1 to Alliant Energy’s Form 8-K, filed November 23, 2020 (File No. 1-9894)
4.5	Indenture, dated as of June 20, 1997, between WPL and Wells Fargo Bank, N.A., Successor, as Trustee (incorporated by reference to Exhibit 4.33 to Amendment No. 2 to WPL’s Registration Statement on Form S-3 (Reg. No. 033-60917))
4.5a	First Supplemental Indenture, dated September 16, 2021, among WPL, Wells Fargo Bank, N.A., as Original Trustee, and U.S. Bank N.A., as Series Trustee (incorporated by reference to Exhibit 4.1 to WPL's Form 8-K, filed September 16, 2021 (File No. 0-337))
4.6	Officers’ Certificate, dated as of July 28, 2004, creating WPL’s 6.25% Debentures due July 31, 2034 (incorporated by reference to Exhibit 4.1 to WPL’s Form 8-K, filed August 2, 2004 (File No. 0-337))
4.7	Officers’ Certificate, dated as of August 8, 2007, creating WPL’s 6.375% Debentures due August 15, 2037 (incorporated by reference to Exhibit 4.1 to WPL’s Form 8-K, filed August 9, 2007 (File No. 0-337))
4.8	Officer’s Certificate, dated as of October 1, 2008, creating WPL’s 7.60% Debentures due October 1, 2038 (incorporated by reference to Exhibit 4.2 to WPL’s Form 8-K, filed October 2, 2008 (File No. 0-337))
4.9	Officers’ Certificate, dated as of November 19, 2012, creating WPL’s 2.25% Debentures due November 15, 2022 (incorporated by reference to Exhibit 4.1 to WPL’s Form 8-K, filed November 19, 2012 (File No. 0-337))
4.10	Officers’ Certificate, dated as of October 14, 2014, creating WPL’s 4.10% Debentures due October 15, 2044 (incorporated by reference to Exhibit 4.1 to WPL’s Form 8-K, filed October 14, 2014 (File No. 0-337))
4.11	Officers’ Certificate, dated as of October 10, 2017, creating WPL’s 3.05% Debentures due October 15, 2027 (incorporated by reference to Exhibit 4.1 to WPL’s Form 8-K, filed October 10, 2017 (File No. 0-337))
4.12	Officers’ Certificate, dated as of June 24, 2019, creating WPL’s 3.00% Debentures due July 1, 2029 (incorporated by reference to Exhibit 4.1 to WPL’s Form 8-K, filed June 24, 2019 (File No. 0-337))
4.13	Officers’ Certificate, dated as of April 2, 2020, creating WPL’s 3.65% Debentures due April 1, 2050 (incorporated by reference to Exhibit 4.1 to WPL’s Form 8-K, filed April 2, 2020 (File No. 0-337))
4.14	Indenture (For Senior Unsecured Debt Securities), dated as of August 20, 2003, between IPL and The Bank of New York Mellon Trust Co., N.A. (f/k/a The Bank of New York Trust Co., N.A.), as Trustee (incorporated by reference to Exhibit 4.11 to IPL’s Registration Statement on Form S-3 (Reg. No. 333-108199))
4.15	Officer’s Certificate, dated as of October 14, 2003, creating IPL’s 6.45% Senior Debentures due October 15, 2033 (incorporated by reference to Exhibit 4.1 to IPL’s Form 8-K, filed October 15, 2003 (File No. 1-4117))
4.16	Officer’s Certificate, dated as of May 3, 2004, creating IPL’s 6.30% Senior Debentures due May 1, 2034 (incorporated by reference to Exhibit 4.1 to IPL’s Form 8-K, filed May 5, 2004 (File No. 1-4117))

101

Exhibit Number	Description
4.16a	Officer’s Certificate, dated as of August 2, 2004, reopening IPL’s 6.30% Senior Debentures due May 1, 2034 (incorporated by reference to Exhibit 4.1 to IPL’s Form 8-K, filed August 5, 2004 (File No. 1-4117))
4.17	Officer’s Certificate, dated as of July 18, 2005, creating IPL’s 5.50% Senior Debentures due July 15, 2025 (incorporated by reference to Exhibit 4 to IPL’s Form 8-K, filed July 19, 2005 (File No. 1-4117))
4.18	Officer’s Certificate, dated as of July 7, 2009, creating IPL’s 6.25% Senior Debentures due July 15, 2039 (incorporated by reference to Exhibit 4.1 to IPL’s Form 8-K, filed July 8, 2009 (File No. 1-4117))
4.19	Officer’s Certificate, dated as of October 8, 2013, creating IPL’s 4.70% Senior Debentures due October 15, 2043 (incorporated by reference to Exhibit 4.1 to IPL’s Form 8-K, filed October 8, 2013 (File No. 1-4117))
4.20	Officer’s Certificate, dated as of November 24, 2014, creating IPL’s 3.25% Senior Debentures due December 1, 2024 (incorporated by reference to Exhibit 4.1 to IPL’s Form 8-K, filed November 24, 2014 (File No. 1-4117))
4.20a	Officer’s Certificate, dated as of November 15, 2017, reopening IPL’s 3.25% Senior Debentures due December 1, 2024 (incorporated by reference to Exhibit 4.1 to IPL’s Form 8-K, filed November 15, 2017 (File No. 1-4117))
4.21	Officer’s Certificate, dated as of August 18, 2015, creating IPL’s 3.40% Senior Debentures due August 15, 2025 (incorporated by reference to Exhibit 4.1 to IPL’s Form 8-K, filed August 18, 2015 (File No. 1-4117))
4.22	Officer’s Certificate, dated as of September 15, 2016, creating IPL’s 3.70% Senior Debentures due September 15, 2046 (incorporated by reference to Exhibit 4.1 to IPL’s Form 8-K, filed September 15, 2016 (File No. 1-4117))
4.23	Officer’s Certificate, dated as of September 26, 2018, creating IPL’s 4.10% Senior Debentures due September 26, 2028 (incorporated by reference to Exhibit 4.1 to IPL’s Form 8-K, filed September 26, 2018 (File No. 1-4117))
4.24	Officer’s Certificate, dated as of April 1, 2019, creating IPL’s 3.60% Senior Debentures due April 1, 2029 (incorporated by reference to Exhibit 4.1 to IPL’s Form 8-K, filed April 1, 2019 (File No. 1-4117))
4.25	Officer’s Certificate, dated as of September 26, 2019, creating IPL’s 3.50% Senior Debentures due September 30, 2049 (incorporated by reference to Exhibit 4.1 to IPL’s Form 8-K, filed September 26, 2019 (File No. 1-4117))
4.26	Officer’s Certificate, dated as of June 2, 2020, creating IPL’s 2.3% Senior Debentures due June 1, 2030 (incorporated by reference to Exhibit 4.1 to IPL’s Form 8-K, filed June 2, 2020 (File No. 1-4117))
4.27	Officer’s Certificate, dated as of November 19, 2021, creating IPL’s 3.1% Senior Debentures due November 30, 2051 (incorporated by reference to Exhibit 4.1 to IPL’s Form 8-K, filed November 19, 2021 (File No. 1-4117))
4.28	Description of Common Stock of Alliant Energy (incorporated by reference to Exhibit 4.26 to Alliant Energy’s Form 10-K for the year 2019 (File No. 1-9894))
10.1	Term Loan Credit Agreement, dated as of March 3, 2020, among AEF, Alliant Energy, KeyBank N.A. and the lender parties set forth therein (incorporated by reference to Exhibit 10.1 to Alliant Energy’s Form 8-K, filed March 5, 2020 (File No. 1-9894))
10.2#	Amended and Restated OIP, amended in 2015 (incorporated by reference to Appendix A to Alliant Energy’s definitive proxy statement filed on Schedule 14A on March 24, 2015 (File No. 1-9894))
10.2a#	Amendment to the Amended and Restated OIP (incorporated by reference to Exhibit 10.6a to Alliant Energy’s Form 10-K for the year 2018 (File No. 1-9894))
10.2b#	Form of Performance Share Agreement pursuant to the Amended and Restated OIP, amended in 2019 (incorporated by reference to Exhibit 10.6c to Alliant Energy’s Form 10-K for the year 2018 (File No. 1-9894))
10.2c#	Form of Restricted Stock Unit Agreement pursuant to the Amended and Restated OIP, amended in 2019 (incorporated by reference to Exhibit 10.6e to Alliant Energy’s Form 10-K for the year 2018 (File No. 1-9894))
10.2d#	Form of Performance Restricted Stock Unit Agreement pursuant to the Amended and Restated OIP, amended in 2019 (incorporated by reference to Exhibit 10.6g to Alliant Energy’s Form 10-K for the year 2018 (File No. 1-9894))
10.3	2020 OIP (incorporated by reference to Appendix A to Alliant Energy’s definitive proxy statement filed on Schedule 14A on April 9, 2020 (File No. 1-9894))
10.3a#	Form of Performance Share Agreement pursuant to the 2020 OIP (incorporated by reference to Exhibit 10.1a to Alliant Energy’s Form 10-Q for the quarter ended June 30, 2020 (File No. 1-9894))
10.3b#	Form of Restricted Stock Unit Agreement pursuant to the 2020 OIP (incorporated by reference to Exhibit 10.1b to Alliant Energy’s Form 10-Q for the quarter ended June 30, 2020 (File No. 1-9894))
10.3c#	Form of Performance Restricted Stock Unit Agreement pursuant to the 2020 OIP (incorporated by reference to Exhibit 10.1c to Alliant Energy’s Form 10-Q for the quarter ended June 30, 2020 (File No. 1-9894))
10.3d#	Form of Performance Share Agreement pursuant to the 2020 OIP, amended in 2022
10.3e#	Form of Restricted Stock Unit Agreement pursuant to the 2020 OIP, amended in 2022
10.3f#	Form of Performance Restricted Stock Unit Agreement (Diversity Metric) pursuant to the 2020 OIP, amended in 2022
10.3g#	Form of Performance Restricted Stock Unit Agreement (Net Income Metric) pursuant to the 2020 OIP, amended in 2022
10.4#	DCP, as amended and restated effective January 1, 2011 (incorporated by reference to Exhibit 10.1 to Alliant Energy’s Form 8-K, filed December 14, 2010 (File No. 1-9894))
10.4a#	Amendment to the DCP, as amended and restated (incorporated by reference to Exhibit 10.2 to Alliant Energy’s Form 8-K, filed December 5, 2011 (File No. 1-9894))
10.5#	IES Industries Inc. Amended and Restated Key Employee Deferred Compensation Agreement, as amended (incorporated by reference to Exhibit 10.7 to Alliant Energy’s Form 10-K for the year 2015 (File No. 1-9894))
10.6#	Alliant Energy Rabbi Trust Agreement for DCPs (incorporated by reference to Exhibit 10.19 to Alliant Energy’s Form 10-K for the year 2005 (File No. 1-9894))
10.6a#	Amendment to the Alliant Energy Rabbi Trust Agreement for DCPs (incorporated by reference to Exhibit 10.2 to Alliant Energy’s Form 10-Q for the quarter ended June 30, 2015 (File No. 1-9894))
10.6b#	Second Amendment to the Alliant Energy Rabbi Trust Agreement for DCPs (incorporated by reference to Exhibit 10.3 to Alliant Energy’s Form 10-Q for the quarter ended June 30, 2015 (File No. 1-9894))
10.7#	Alliant Energy Excess Retirement Plan (incorporated by reference to Exhibit 10.1 to Alliant Energy’s Form 10-Q for the quarter ended September 30, 2008 (File No. 1-9894))

102

Exhibit Number	Description
10.7a#	Amendment to the Alliant Energy Excess Retirement Plan (incorporated by reference to Exhibit 10.4 to Alliant Energy’s Form 8-K, filed December 5, 2011 (File No. 1-9894))
10.8#	Form of Supplemental Retirement Plan (SRP) Agreement by and between Alliant Energy and J.O. Larsen (incorporated by reference to Exhibit 10.3 to Alliant Energy’s Form 8-K, filed December 12, 2008 (File No. 1-9894))
10.9#	Alliant Energy Defined Contribution SRP (incorporated by reference to Exhibit 10.1 to Alliant Energy’s Form 10-Q for the quarter ended September 30, 2010 (File No. 1-9894))
10.9a#	Amendment to the Alliant Energy Defined Contribution SRP (incorporated by reference to Exhibit 10.3 to Alliant Energy’s Form 8-K, filed December 5, 2011 (File No. 1-9894))
10.9b#	Amendment to the Alliant Energy Defined Contribution SRP (incorporated by reference to Exhibit 10.1 to Alliant Energy’s Form 8-K, filed March 12, 2014 (File No. 1-9894))
10.10#	Form of Key Executive Employment and Severance Agreement (KEESA), by and between Alliant Energy and J.O. Larsen (incorporated by reference to Exhibit 10.1 to Alliant Energy’s Form 8-K, filed October 28, 2021 (File No. 1-9894))
10.11#	Form of KEESA, by and between Alliant Energy and each of J.H. Gallegos, R.J. Durian, D.A. de Leon and T.L. Kouba (incorporated by reference to Exhibit 10.2 to Alliant Energy’s Form 8-K, filed October 28, 2021 (File No. 1-9894))
10.12#	Executive Officer Severance Benefit Plan, as amended and restated, effective October 29, 2018 (incorporated by reference to Exhibit 10.1 to Alliant Energy’s Form 10-Q for the quarter ended September 30, 2018 (File No. 1-9894))
10.13#	Terms of Alliant Energy Executive Performance Pay Plan (incorporated by reference to Exhibit 10.18 to Alliant Energy’s Form 10-K for the year 2015 (File No. 1-9894))
10.14#	Summary of Compensation and Benefits for Non-Employee Directors of Alliant Energy, IPL and WPL, effective January 1, 2022
21.1	Subsidiaries of Alliant Energy
23.1	Consent of Independent Registered Public Accounting Firm for Alliant Energy
23.2	Consent of Independent Registered Public Accounting Firm for IPL
23.3	Consent of Independent Registered Public Accounting Firm for WPL
31.1	Certification of the Chief Executive Officer for Alliant Energy
31.2	Certification of the Chief Financial Officer for Alliant Energy
31.3	Certification of the Chief Executive Officer for IPL
31.4	Certification of the Chief Financial Officer for IPL
31.5	Certification of the Chief Executive Officer for WPL
31.6	Certification of the Chief Financial Officer for WPL
32.1	Written Statement of the Chief Executive Officer and Chief Financial Officer Pursuant to 18 U.S.C.§1350 for Alliant Energy
32.2	Written Statement of the Chief Executive Officer and Chief Financial Officer Pursuant to 18 U.S.C.§1350 for IPL
32.3	Written Statement of the Chief Executive Officer and Chief Financial Officer Pursuant to 18 U.S.C.§1350 for WPL
101.INS	Inline XBRL Instance Document - the instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document
101.SCH	Inline XBRL Taxonomy Extension Schema Document
101.CAL	Inline XBRL Taxonomy Extension Calculation Linkbase Document
101.LAB	Inline XBRL Taxonomy Extension Label Linkbase Document
101.PRE	Inline XBRL Taxonomy Extension Presentation Linkbase Document
101.DEF	Inline XBRL Taxonomy Extension Definition Linkbase Document
104	Cover Page Interactive Data File (embedded within the Inline XBRL document)

# A management contract or compensatory plan or arrangement.

ITEM 16. FORM 10-K SUMMARY

None.

103

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrants have duly caused this report to be signed on their behalf by the undersigned, thereunto duly authorized on the 18th day of February 2022.

ALLIANT ENERGY	INTERSTATE POWER	WISCONSIN POWER
CORPORATION	AND LIGHT COMPANY	AND LIGHT COMPANY
By: /s/ John O. Larsen	By: /s/ John O. Larsen	By: /s/ John O. Larsen
John O. Larsen	John O. Larsen	John O. Larsen
Chair, President and Chief Executive Officer	Chair and Chief Executive Officer	Chair and Chief Executive Officer

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the Registrants and in the capacities indicated on the 18th day of February 2022.

ALLIANT ENERGY	INTERSTATE POWER	WISCONSIN POWER
CORPORATION	AND LIGHT COMPANY	AND LIGHT COMPANY
/s/ John O. Larsen	/s/ John O. Larsen	/s/ John O. Larsen
John O. Larsen	John O. Larsen	John O. Larsen
Chair, President, Chief Executive Officer and Director (Principal Executive Officer)	Chair, Chief Executive Officer and Director (Principal Executive Officer)	Chair, Chief Executive Officer and Director (Principal Executive Officer)
/s/ Robert J. Durian	/s/ Robert J. Durian	/s/ Robert J. Durian
Robert J. Durian	Robert J. Durian	Robert J. Durian
Executive Vice President and Chief Financial Officer (Principal Financial Officer)	Executive Vice President and Chief Financial Officer (Principal Financial Officer)	Executive Vice President and Chief Financial Officer (Principal Financial Officer)
/s/ Benjamin M. Bilitz	/s/ Benjamin M. Bilitz	/s/ Benjamin M. Bilitz
Benjamin M. Bilitz	Benjamin M. Bilitz	Benjamin M. Bilitz
Chief Accounting Officer and Controller (Principal Accounting Officer)	Chief Accounting Officer and Controller (Principal Accounting Officer)	Chief Accounting Officer and Controller (Principal Accounting Officer)
/s/ Patrick E. Allen	/s/ Patrick E. Allen	/s/ Patrick E. Allen
Patrick E. Allen, Director	Patrick E. Allen, Director	Patrick E. Allen, Director
/s/ N. Joy Falotico	/s/ N. Joy Falotico	/s/ N. Joy Falotico
N. Joy Falotico, Director	N. Joy Falotico, Director	N. Joy Falotico, Director
/s/ Michael D. Garcia	/s/ Michael D. Garcia	/s/ Michael D. Garcia
Michael D. Garcia, Director	Michael D. Garcia, Director	Michael D. Garcia, Director
/s/ Singleton B. McAllister	/s/ Singleton B. McAllister	/s/ Singleton B. McAllister
Singleton B. McAllister, Director	Singleton B. McAllister, Director	Singleton B. McAllister, Director
/s/ Roger K. Newport	/s/ Roger K. Newport	/s/ Roger K. Newport
Roger K. Newport, Director	Roger K. Newport, Director	Roger K. Newport, Director
/s/ Thomas F. O’Toole	/s/ Thomas F. O’Toole	/s/ Thomas F. O’Toole
Thomas F. O’Toole, Director	Thomas F. O’Toole, Director	Thomas F. O’Toole, Director
/s/ Dean C. Oestreich	/s/ Dean C. Oestreich	/s/ Dean C. Oestreich
Dean C. Oestreich, Director	Dean C. Oestreich, Director	Dean C. Oestreich, Director
/s/ Carol P. Sanders	/s/ Carol P. Sanders	/s/ Carol P. Sanders
Carol P. Sanders, Director	Carol P. Sanders, Director	Carol P. Sanders, Director
/s/ Susan D. Whiting	/s/ Susan D. Whiting	/s/ Susan D. Whiting
Susan D. Whiting, Director	Susan D. Whiting, Director	Susan D. Whiting, Director

104

EX-10.3D

Exhibit 10.3d

FORM OF ALLIANT ENERGY CORPORATION

PERFORMANCE SHARE AGREEMENT

THIS PERFORMANCE SHARE AGREEMENT (this “Agreement”) is made and entered into as of this ___ day of ______ 20__ (the “Grant Date”) by and between Alliant Energy Corporation, a Wisconsin corporation (the “Company”), and ###PARTICIPANT_NAME###, a key employee of the Company (the “Employee”).

R E C I T A L S

WHEREAS, the Company has in effect the Alliant Energy Corporation 2020 Omnibus Incentive Plan (the “Plan”), the terms of which, to the extent not stated herein, are specifically incorporated by reference in this Agreement and capitalized terms used herein which are not otherwise defined shall have the meaning set forth in the Plan;

WHEREAS, one of the purposes of the Plan is to permit the grant of various equity-based incentive awards, including performance shares (the “Performance Shares”), to individuals selected by the Compensation and Personnel Committee of the Board of Directors of the Company (the “Committee”);

WHEREAS, the Employee is now employed by the Company or an Affiliate of the Company in a key capacity and has exhibited judgment, initiative and efforts which have contributed materially to the successful performance of the Company and/or its Affiliates; and

WHEREAS, the Company desires the Employee to remain as an employee of the Company or its Affiliates and wishes to provide the Employee with the opportunity to secure or increase his or her stock ownership in the Company in order to develop even a stronger incentive to put forth maximum effort for the continued success and growth of the Company.

A G R E E M E N T

NOW, THEREFORE, in consideration of the premises and of the covenants and agreements herein set forth, the parties hereby mutually covenant and agree as follows:

1.Award. Subject to the terms of this Agreement and the Plan, the Employee is hereby granted ###TOTAL_AWARDS### target Performance Shares on the Grant Date. Performance Shares granted under this Agreement are units that will be reflected in a book account maintained by the Company during the Performance Period set forth below, and that will be settled in Shares to the extent provided in this Agreement and the Plan.

2.Performance Period; Performance Goals.

(a)The “Performance Period” is the period beginning on ###DATE### and ending on ###DATE###.

(b)Except as otherwise provided in this Agreement (including Section 9 below), the Performance Shares will become earned based on achievement of the requisite performance goal or performance goals (the “Performance Goals”) determined in accordance with the provisions of Exhibit 1, which is attached to and forms a part of this Agreement. Any unearned Performance Shares automatically will terminate and be cancelled, without the payment of any consideration following the last day of the Performance Period.

3.Settlement of Awards. Subject to Section 9 below, the Company shall deliver to the Employee one Share for each Performance Share earned by the Employee, as determined in accordance with the provisions of Exhibit 1, with fractional shares rounded up to the nearest whole share.

4.Time of Payment. Except as otherwise provided in this Agreement (including Section 9 below), payment of Performance Shares earned in accordance with the provisions of Section 3 will be delivered as soon as practicable (but in any event within 75 days) following the last day of the Performance Period set forth in

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Section 2(a), subject to the Committee approving in writing as to the satisfaction of the requisite Performance Goal or Goals.

5.Retirement, Disability, or Death During Performance Period and Prior to a Change in Control. If the Employee’s employment with the Company and its Affiliates terminates during the Performance Period and prior to a Change in Control because of the Employee’s Retirement (as defined below), Disability, or death, the Employee shall be entitled to the full value of the Award earned in accordance with Exhibit 1, determined at the end of the Performance Period, so long as the termination event occurs after the end of the first year of the Performance Period and only if and to the extent the Performance Goals are met. If the termination event occurs during the first year of the Performance Period, the Employee will be entitled to a prorated value of the Award, earned in accordance with Exhibit 1, determined at the end of the Performance Period and only if and to the extent the Performance Goals are met, based on a fraction, the numerator of which is the number of months the Employee was employed during the Performance Period and the denominator of which is 12.

6.Involuntary Termination Without Cause During Performance Period and Prior to a Change in Control. If the Employee’s employment with the Company and its Affiliates terminates during the Performance Period and prior to a Change in Control because of an Involuntary Termination without Cause (as defined below), the Employee shall be entitled to the prorated value of the Award earned, determined at the end of the Performance Period and only if and to the extent the Performance Goals are met, based on a fraction, the numerator of which is the number of months the Employee was employed during the Performance Period and the denominator of which is 36.

7.Other Terminations of Employment During Performance Period. If the Employee’s employment with the Company and its Affiliates terminates during the Performance Period and prior to a Change in Control for any reason other than the Employee’s Retirement, Disability, Involuntary Termination without Cause, or death, the Performance Shares granted under this Agreement automatically will terminate and be cancelled on the date of such termination of employment.

8.Dividend Equivalents.

(a)    After the Performance Period has ended (or, if a Change in Control occurs during the Performance Period, the effective date of the Change in Control), dividend equivalents (“Dividend Equivalents”) will be calculated and credited to the account of the Employee with respect to the percentage of Performance Shares that are earned (as determined in accordance with Section 3 or Section 9(a)(i) as applicable). Dividend Equivalents will be credited as additional Performance Shares, the number of which will be equal to the number of whole Shares that could be purchased with the amount of the Dividend Equivalents, based on the Fair Market Value of the Shares as of the dividend payment date and the number of earned Performance Shares (as determined in accordance with Section 3 or Section 9(a)(i) as applicable).

(b)    Any Dividend Equivalents credited to the Employee’s account pursuant to this Section 8 shall not be vested or paid until the dates of vesting or payment of the Performance Shares with respect to which such Dividend Equivalents are credited, and such Dividend Equivalents shall be subject to the same restrictions and other terms and conditions as apply to the Performance Shares with respect to which they were credited.

(c)    No Dividend Equivalents shall be credited to the Employee with respect to record dates occurring prior to the Grant Date or with respect to record dates occurring on or after the date, if any, on which the Performance Shares are cancelled and terminated.

9.Change in Control.

(a)    No Termination of Employment Prior to a Change in Control.

(i)    Notwithstanding anything to the contrary in the Plan, this Agreement, or the Employee’s employment agreement or any other agreement to which the Employee is a party, if a Change in Control occurs during the Performance Period and the Employee’s employment does not terminate before the effectiveness of the Change in Control, then the Employee shall be entitled to the target

2022 Performance Shares 2

Performance Shares, which automatically will convert into a contractual right to receive a cash payment (the “Cash Payment Right”) in an amount equal to (i) the number of target Performance Shares (including any additional Performance Shares determined in accordance with Section 8(a)), multiplied by (ii) the per Share Fair Market Value as of the trading day immediately preceding the effective date of the Change in Control. After such conversion, no interest or Dividend Equivalents will be accrued, credited or paid with respect to the Cash Payment Right. Any portion of the Performance Shares that is not converted into the Cash Payment Right automatically shall terminate and be cancelled immediately prior to the effectiveness of the Change in Control, without the payment of any consideration therefor.

(ii)    Notwithstanding anything to the contrary in the Plan, this Agreement, or the Employee’s employment agreement or any other agreement to which the Employee is a party, the Cash Payment Right shall be paid as soon as practicable (but in any event within 75 days) after the last day of the Performance Period set forth in Section 2(a), provided that the Employee remains continuously employed by the Company or an Affiliate or any successor thereto through the last day of such Performance Period. Notwithstanding the immediately preceding sentence, in the event that the Employee experiences a termination of employment due to the Employee’s Retirement (as defined below), Disability, or death or an involuntary termination of employment by action of the Company(or its successor)(other than a termination due to Cause) or due to the Employee’s resignation for Good Reason prior to the last day of the Performance Period set forth in Section 2(a), the Cash Payment Right will be paid in accordance with the first sentence of this Section 9(a)(ii) as though the Employee remained continuously employed by the Company or an Affiliate or any successor thereto through the last day of the Performance Period.

(b)    Certain Terminations of Employment Prior to a Change in Control. Solely for purposes of Sections 5 and 6 of the Agreement, if the Employee’s employment terminates for any of the reasons set forth in such Sections 5 and 6 prior to a Change in Control and a Change in Control occurs during the Performance Period, then the Employee shall be entitled to the earned Performance Shares determined in accordance with Section 9(a)(i) in lieu of any amount set forth in Section 5 or Section 6, as applicable, which Performance Shares automatically shall convert into a contractual right to receive the Cash Payment Right. After such conversion, no interest or Dividend Equivalents will be accrued, credited or paid with respect to the Cash Payment Right. For the avoidance of doubt, the Cash Payment Right will be paid at such time provided under Section 4.

10.Definitions.

(a)“Involuntary Termination without Cause” shall mean that the Employee experiences a termination of employment due to the Employee’s (i) receipt of a written notification that his or her position is being eliminated as a result of a structured job elimination program or (ii) resignation for a Pre-Change in Control Good Reason.

(b)“Pre-Change in Control Good Reason” shall mean that an applicable event occurs and the Employee provides notice to the Company of the existence of the event within 90 days of the initial existence of the event, the Company fails to cure the event within 30 days of such notice and the Employee resigns within 30 days following the last day of such 30-day cure period. The applicable events are any one or more of the following: (i) a material diminution in the Employee’s base compensation and (ii) a material diminution in the Employee’s authority, duties, or responsibilities.

(c)“Retirement” shall mean the Employee’s employment terminates (with the consent of the Company) after he or she has reached age 55 and the Employee’s age, in whole years, added to the number of whole years of the Employee’s continuous employment with the Company total 65 or more.

11.Non-transferability of Performance Shares. The Performance Shares shall not be assignable, alienable, saleable or transferable by the Employee other than by will or the laws of descent and distribution prior to settlement of the Awards pursuant to Section 3 (or, if applicable, Section 9); provided, however, that the Employee shall be entitled, in the manner provided in Section 13 hereof, to designate a beneficiary to receive any Shares or cash issuable with respect to the Award upon the death of the Employee.

2022 Performance Shares 3

12.Tax Withholding. The Company may deduct and withhold from any cash otherwise payable to the Employee such amount as may be required for the purpose of satisfying the Company’s obligation to withhold federal, state or local taxes. Further, in the event the amount so withheld is insufficient for such purpose, the Company may require that the Employee pay to the Company upon its demand or otherwise make arrangements satisfactory to the Company for payment of, such amount as may be requested by the Company in order to satisfy its obligation to withhold any such taxes.

Unless otherwise determined by the Company, by this Agreement, the Employee agrees that the Company shall withhold Shares otherwise issuable to the Employee (the “Withholding Election”) having a Fair Market Value on the date income is recognized (the “Tax Date”) pursuant to the settlement of the Award equal to the minimum amount required to be withheld (or such other applicable rate permitted by the Company that avoids adverse treatment for financial accounting purposes). If the number of Shares withheld to satisfy withholding tax requirements includes a fractional Share, the number of Shares withheld shall be reduced to the next lower whole number and the Employee shall deliver cash in lieu of such fractional Share, or otherwise make arrangements satisfactory to the Company for payment of such amount. Regardless of any action taken by the Company, the Employee understands that the ultimate liability for all tax-related items related to the Award is and remains the Employee’s responsibility and may exceed the amount, if any, withheld by the Company. The Employee further acknowledges that the Company (i) makes no representations or undertakings regarding the treatment of any tax-related items in connection with any aspect of the Award, including, but not limited to, the grant, vesting or settlement of the Award, the subsequent sale of Shares acquired pursuant to the Award, or the receipt of any dividends and/or Dividend Equivalents and (ii) does not commit to and is under no obligation to structure the terms of the grant or any other aspect of the Award to reduce or eliminate the Employee’s liability for tax-related items related to the Award or achieve any particular tax result.

13.Designation of Beneficiary. The Employee shall be permitted to designate one or more beneficiaries (each, a “Beneficiary”) on a Company-approved form who shall be entitled to payouts hereunder, to the extent payouts are made, after the death of the Employee. The terms and conditions of any such designation (including any changes thereto by the Employee) shall be subject to the terms and conditions of such Company-approved beneficiary designation form. If no such beneficiary designation is in effect at the time of the Employee’s death, or if no designated Beneficiary survives the Employee or if such designation conflicts with law, the Employee’s estate acting through his or her legal representative shall be entitled to receive payouts hereunder, to the extent they are made, after the death of the Employee. If the Committee is in doubt as to the right of any person to the Performance Shares or any payout thereunder, the Company may refuse to settle such matter, without liability for any interest or dividends on the Performance Shares, until the Committee determines the person entitled to the Performance Shares or any payout thereunder, or the Company may apply to any court of appropriate jurisdiction and such application shall be a complete discharge of the liability of the Company therefor.

14.Transfer Restriction. Any Shares delivered pursuant to Section 3 hereof shall thereafter be freely transferable by the Employee, provided that the Employee agrees for himself or herself and his or her heirs, legatees and legal representatives, with respect to all Shares acquired pursuant to the terms and conditions of this Agreement (or any Shares issued pursuant to a stock dividend or stock split thereon or any securities issued in lieu thereof or in substitution or exchange therefor), that he or she and his or her heirs, legatees and legal representatives will not sell or otherwise dispose of such shares except pursuant to a registration statement filed by the Company with the Securities and Exchange Commission under the Securities Act of 1933, as amended (the “Act”), or except in a transaction which is determined by counsel to the Company to be exempt from registration under the Act and any applicable state securities laws; and to execute and deliver to the Company such investment representations and warranties, and to take such other actions, as counsel for the Company determines may be necessary or appropriate for compliance with the Act and any other applicable securities laws. The Employee agrees that any certificates representing any of the Shares acquired pursuant to the terms and conditions of this Agreement may bear such legend or legends as the Company deems appropriate in order to assure compliance with applicable securities laws.

15.Status of Employee. The Employee shall not be deemed for any purposes to be a shareowner of the Company with respect to any of the Performance Shares except to the extent that the Company has delivered Shares pursuant to Section 3 hereof. Therefore, the Employee will not have the right of shareowners to vote or, subject to Section 8, to receive dividends or distributions of any kind prior to the Company delivering Shares pursuant to Section 3 hereof. Neither the Plan nor the Performance Shares

2022 Performance Shares 4

shall confer upon the Employee any right to continue as an employee of the Company or any of its Affiliates, nor to interfere in any way with the right of the Company to terminate the employment or directorship of the Employee at any time.

16.Powers of the Company Not Affected. The existence of the Performance Shares shall not affect in any way the right or power of the Company or its shareowners to make or authorize any or all adjustments, recapitalizations, reorganizations or other changes in the Company’s capital structure or its business, or any merger or consolidation of the Company, or any issuance of bonds, debentures, preferred or prior preference stock senior to or affecting the Shares or the rights thereof, or dissolution or liquidation of the Company, or any sale or transfer of all or any part of the Company’s assets or business or any other corporate act or proceeding, whether of a similar character or otherwise.

17.Interpretation by the Committee. As a condition of the granting of the Performance Shares, the Employee agrees, for himself or herself and for his or her legal representatives or guardians, that this Agreement shall be interpreted by the Committee and that any interpretation by the Committee of the terms of this Agreement and any determination made by the Committee pursuant to this Agreement shall be final, binding and conclusive.

18.Miscellaneous.

(a)This Agreement shall be governed and construed in accordance with the internal laws of the State of Wisconsin applicable to contracts made and to be performed therein between residents thereof. As a condition of the granting of the Performance Shares, the Employee irrevocably consents to the nonexclusive jurisdiction and venue of the state and federal courts located in the State of Wisconsin.

(b)The Plan and this Agreement set forth the entire understanding between the Company and the Employee with respect to the subject matter hereof and shall supersede in all respects, and the Employee hereby waives all rights under, any prior or other agreement or understanding between the parties with respect to such subject matter, including, but not limited to, any Key Executive Employment and Severance Agreement. For the avoidance of doubt, the Plan and this Agreement shall control in the event there is any express conflict between the Plan and this Agreement and any prior or other agreement or understanding between the parties.

(c)This Agreement may not be amended or modified except by the written consent of the parties hereto. Notwithstanding the foregoing, the Committee need not obtain Employee (or other interested party) consent for any such action: (i) to the extent the action is deemed necessary by the Committee to comply with any applicable law; (ii) to the extent the action is deemed necessary by the Committee to preserve favorable accounting or tax treatment for the Company of any Award; (iii) to the extent the Committee determines that such action does not materially and adversely affect the value of an Award or that such action is in the best interest of the affected Employee; or (iv) to the extent unilateral action by the Committee is permitted under Section 14(c) of the Plan.

(d)The Award and any Shares or cash issued thereunder shall be subject to potential cancellation, rescission, payback, recoupment or other action in accordance with the terms of any Company clawback policy (the “Clawback Policy”), as then in effect and as it may be amended from time to time, to the extent the Clawback Policy applies to the Award and any Shares or cash issued thereunder (including a Clawback Policy implemented or amendments made thereto after the Grant Date for the Award). By accepting the Performance Shares, the Employee agrees to execute any additional documents as may be requested by the Company to affect the Company’s application, implementation and adoption of a Clawback Policy with respect to the Award and any Shares or cash issued thereunder.

(e)The captions of this Agreement are inserted for convenience of reference only and shall not be taken into account in construing this Agreement.

2022 Performance Shares 5

IN WITNESS WHEREOF, the Company has caused this Agreement to be executed by its duly authorized officer and the Employee has hereunto affixed his or her hand as of the day and year first above written.

ALLIANT ENERGY CORPORATION
(the “Company”)

By:

Its:

EMPLOYEE:

Employee’s Signature

    ###PARTICIPANT_NAME###    
Employee’s Printed Name

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EXHIBIT 1

PERFORMANCE SHARE GRANT – PERFORMANCE GOALS

1.    Purpose: The purpose of this Exhibit 1 is to set forth the Performance Goal or Goals that will be applied to determine the amount of the Award that will be earned under the terms of the attached Performance Share Agreement (the “Agreement”). This Exhibit 1 is incorporated into and forms a part of the Agreement.

PARTICIPANT_NAME	20__
Grant Date	###GRANT_DATE###
Grant Date Fair Market Value	###MARKET_PRICE_AT_TIME_OF_GRANT###
Performance Shares (Target)	###TOTAL_AWARDS###
Performance Period	###DATE### through ###DATE###

2.    Performance Goals: The Award will be based on the Company’s Total Shareholder Return (TSR) performance (which represents stock price appreciation plus dividends reinvested) based on the three-year average relative to an investor-owned utility peer group. The peer group is defined as the group that comprises the Edison Electric Institute (EEI) Stock Index.

3.    Amount of Award: Actual awards will be based on Company performance as specified above and can range from 0 to 200 percent of target. The number of Performance Shares earned by the Employee shall be determined in accordance with the following schedule:

3-yr Total Shareholder Return – Percentile Relative to Peer Group*	% of Target Performance Shares  Paid Out
__ percentile or greater	___%
__ percentile	___%
__ percentile	___%
__ percentile	___%
__ percentile	___%
__ percentile	__%
__ percentile	__%
Below __ percentile	__%

* Peer Group consists of companies comprising the Edison Electric Institute (EEI) Stock Index.

** Awards will be prorated for achievement of performance between the performance targets: If the TSR percentile relative to the Peer Group is between any two data points, the corresponding percentage of Performance Shares earned shall be determined by interpolation between the corresponding data points.

2022 Performance Shares 7

EX-10.3E

Exhibit 10.3e

FORM OF ALLIANT ENERGY CORPORATION

RESTRICTED STOCK UNIT AGREEMENT

THIS RESTRICTED STOCK UNIT AGREEMENT (this “Agreement”) is made and entered into as of this ___ day of ________, 20__ (the “Grant Date”) by and between Alliant Energy Corporation, a Wisconsin corporation (the “Company”), and ###PARTICIPANT_NAME###, a key employee of the Company (the “Employee”).

R E C I T A L S

WHEREAS, the Company has in effect the Alliant Energy Corporation 2020 Omnibus Incentive Plan (the “Plan”), the terms of which, to the extent not stated herein, are specifically incorporated by reference in this Agreement and capitalized terms used herein which are not otherwise defined shall have the meaning set forth in the Plan;

WHEREAS, one of the purposes of the Plan is to permit the grant of various equity-based incentive awards, including time-vesting restricted stock units (“RSUs”), to individuals selected by the Compensation and Personnel Committee of the Board of Directors of the Company (the “Committee”);

WHEREAS, the Employee is now employed by the Company or an Affiliate of the Company in a key capacity and has exhibited judgment, initiative and efforts which have contributed materially to the successful performance of the Company and/or its Affiliates; and

WHEREAS, the Company desires the Employee to remain as an employee of the Company or its Affiliates and wishes to provide the Employee with the opportunity to secure or increase his or her stock ownership in the Company in order to develop even a stronger incentive to put forth maximum effort for the continued success and growth of the Company.

A G R E E M E N T

NOW, THEREFORE, in consideration of the premises and of the covenants and agreements herein set forth, the parties hereby mutually covenant and agree as follows:

1.Award. Subject to the terms of this Agreement and the Plan, the Employee is hereby granted ###TOTAL_AWARDS### RSUs on the Grant Date with a vesting commencement date of ###DATE### (the “Vesting Commencement Date”). RSUs granted under this Agreement are units that will be reflected in a book account maintained by the Company during the Term set forth below, and that will be settled in Shares to the extent provided in this Agreement and the Plan.

2.Term; Vesting Schedule.

(a)    The “Term” is the period beginning on the Vesting Commencement Date and ending on ###DATE###.

(b)    Except as otherwise provided in this Agreement (including Section 9 below), each RSU will become earned and vested (each a “Vested RSU” and, collectively, “Vested RSUs”) on the last day of the Term set forth in Section 2(a), if the Employee is continuously employed with the Company or any of its Affiliates through the last day of the Term.

3.Settlement of Awards. Subject to Section 9 below, the Company shall deliver to the Employee one Share for each Vested RSU, with fractional shares rounded up to the nearest whole share.

4.Time of Payment. Except as otherwise provided in this Agreement (including Section 9 below), payment of Vested RSUs will be delivered as soon as practicable (but in any event within 75 days) following the last day of the Term set forth in Section 2(a).

5.Retirement, Disability, or Death During the Term and Prior to a Change in Control. If the Employee’s employment with the Company and its Affiliates terminates during the Term and prior to a Change in Control because of the Employee’s Retirement (as defined below), Disability, or death, the full number of RSUs shall be treated as Vested

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RSUs, so long as the termination event occurs on or after the first anniversary of the Vesting Commencement Date. If the employment termination event occurs prior to the first anniversary of the Vesting Commencement Date, a pro-rated number of RSUs shall be treated as Vested RSUs, based on a fraction, the numerator of which is the number of months the Employee was employed during the Term and the denominator of which is 12. Any RSUs that do not become Vested RSUs automatically will terminate and be cancelled, without the payment of any consideration, on the date the Employee’s employment with the Company and its Affiliates terminates.

6.Involuntary Termination Without Cause During the Term and Prior to a Change in Control. If the Employee’s employment with the Company and its Affiliates terminates after the first anniversary of the Vesting Commencement Date and prior to a Change in Control because of an Involuntary Termination without Cause (as defined below), a pro-rated number of RSUs shall be treated as Vested RSUs, based on a fraction, the numerator of which is the number of months the Employee was employed following the Vesting Commencement Date and the denominator of which is 36. Any RSUs that do not become Vested RSUs automatically will terminate and be cancelled, without the payment of any consideration, on the date the Employee’s employment with the Company and its Affiliates terminates.

7.Other Terminations of Employment During Term and Prior to Change in Control. If the Employee’s employment with the Company and its Affiliates terminates during the Term and prior to a Change in Control for any reason other than the Employee’s Retirement, Disability, Involuntary Termination without Cause, or death, the RSUs granted under this Agreement automatically will terminate and be cancelled on the date of such termination of employment without the payment of any consideration.

8.Dividend Equivalents.

(a)    After the Term has ended (or, if a Change in Control occurs prior to the end of the Term, the effective date of the Change in Control), dividend equivalents (“Dividend Equivalents”) will be calculated and credited to the account of the Employee with respect to the number of Vested RSUs. Dividend Equivalents will be credited as additional RSUs, the number of which will be equal to the number of whole Shares that could be purchased with the amount of the Dividend Equivalents, based on the Fair Market Value of the Shares as of the dividend payment date and the number of Vested RSUs.

(b)    Any Dividend Equivalents credited to the Employee’s account pursuant to this Section 8 shall not be vested or paid until the dates of vesting or payment of the RSUs with respect to which such Dividend Equivalents are credited, and such Dividend Equivalents shall be subject to the same restrictions and other terms and conditions as apply to the RSUs with respect to which they were credited.

(c)    No Dividend Equivalents shall be credited to the Employee with respect to record dates occurring prior to the Grant Date or with respect to record dates occurring on or after the date, if any, on which the RSUs are cancelled and terminated.

9.Change in Control.

(a)    Notwithstanding anything to the contrary in the Plan, this Agreement, or the Employee’s employment agreement or any other agreement to which the Employee is a party, if a Change in Control occurs during the Term and the Employee’s employment does not terminate before the effectiveness of the Change in Control, then the RSUs automatically will vest and convert into a contractual right to receive a cash payment (the “Cash Payment Right”) in an amount equal to (i) the full number of RSUs (including any additional RSUs determined in accordance with Section 8(a)), multiplied by (ii) the per Share Fair Market Value as of the trading day immediately preceding the effective date of the Change in Control. After such conversion, no interest or Dividend Equivalents will be accrued, credited or paid with respect to the Cash Payment Right.

(b)    Notwithstanding anything to the contrary in the Plan, this Agreement, or the Employee’s employment agreement or any other agreement to which the Employee is a party, the Cash Payment Right shall be paid as soon as practicable (but in any event within 75 days) after the last day of the Term set forth in Section 2(a), provided that the Employee remains continuously employed by the Company or an Affiliate or any successor thereto through the last day of the Term. Notwithstanding the immediately preceding sentence, in the event that the Employee experiences a termination of employment due to the Employee’s Retirement (as defined below), Disability, or death or an involuntary termination of employment by action of the Company (or its successor) (other than a termination due to Cause) or due to the Employee’s resignation for Good Reason prior to the last day of the Term set forth in Section 2(a), the Cash Payment

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Right will be paid in accordance with the first sentence of this Section 9(b) as though the Employee remained continuously employed by the Company or an Affiliate or any successor thereto through the last day of the Term.

10.Definitions.

(a)“Involuntary Termination without Cause” shall mean that the Employee experiences a termination of employment due to the Employee’s (i) receipt of a written notification that his or her position is being eliminated as a result of a structured job elimination program or (ii) resignation for a Pre-Change in Control Good Reason.

(b)“Pre-Change in Control Good Reason” shall mean that an applicable event occurs and the Employee provides notice to the Company of the existence of the event within 90 days of the initial existence of the event, the Company fails to cure the event within 30 days of such notice and the Employee resigns within 30 days following the last day of such 30-day cure period. The applicable events are any one or more of the following: (i) a material diminution in the Employee’s base compensation and (ii) a material diminution in the Employee’s authority, duties, or responsibilities.

(c)“Retirement” shall mean the Employee’s employment terminates (with the consent of the Company) after he or she has reached age 55 and the Employee’s age, in whole years, added to the number of whole years of the Employee’s continuous employment with the Company total 65 or more.

11.Non-transferability of RSUs. The RSUs shall not be assignable, alienable, saleable or transferable by the Employee other than by will or the laws of descent and distribution prior to settlement of the Awards pursuant to Section 3 (or, if applicable, Section 9); provided, however, that the Employee shall be entitled, in the manner provided in Section 13 hereof, to designate a beneficiary to receive any Shares or cash issuable with respect to the Award upon the death of the Employee.

12.Tax Withholding. The Company may deduct and withhold from any cash otherwise payable to the Employee such amount as may be required for the purpose of satisfying the Company’s obligation to withhold federal, state or local taxes. Further, in the event the amount so withheld is insufficient for such purpose, the Company may require that the Employee pay to the Company upon its demand or otherwise make arrangements satisfactory to the Company for payment of, such amount as may be requested by the Company in order to satisfy its obligation to withhold any such taxes.

Unless otherwise determined by the Company, by this Agreement, the Employee agrees that the Company shall withhold Shares otherwise issuable to the Employee (the “Withholding Election”) having a Fair Market Value on the date income is recognized (the “Tax Date”) pursuant to the settlement of the Award equal to the minimum amount required to be withheld (or such other applicable rate permitted by the Company that avoids adverse treatment for financial accounting purposes). If the number of Shares withheld to satisfy withholding tax requirements includes a fractional Share, the number of Shares withheld shall be reduced to the next lower whole number and the Employee shall deliver cash in lieu of such fractional Share, or otherwise make arrangements satisfactory to the Company for payment of such amount. Regardless of any action taken by the Company, the Employee understands that the ultimate liability for all tax-related items related to the Award is and remains the Employee’s responsibility and may exceed the amount, if any, withheld by the Company. The Employee further acknowledges that the Company (i) makes no representations or undertakings regarding the treatment of any tax-related items in connection with any aspect of the Award, including, but not limited to, the grant, vesting or settlement of the Award, the subsequent sale of Shares acquired pursuant to the Award, or the receipt of any dividends and/or Dividend Equivalents and (ii) does not commit to and is under no obligation to structure the terms of the grant or any other aspect of the Award to reduce or eliminate the Employee’s liability for tax-related items related to the Award or achieve any particular tax result.

13.Designation of Beneficiary. The Employee shall be permitted to designate one or more beneficiaries (each, a “Beneficiary”) on a Company-approved form who shall be entitled to payouts hereunder, to the extent payouts are made, after the death of the Employee. The terms and conditions of any such designation (including any changes thereto by the Employee) shall be subject to the terms and conditions of such Company-approved beneficiary designation form. If no such beneficiary designation is in effect at the time of the Employee’s death, or if no designated Beneficiary survives the Employee or if such designation conflicts with law, the Employee’s estate acting through his or her legal representative shall be entitled to receive payouts hereunder, to the extent they are made, after the death of the Employee. If the Committee is in doubt as to the right of any person to the RSUs or any payout

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thereunder, the Company may refuse to settle such matter, without liability for any interest or dividends on the RSUs, until the Committee determines the person entitled to the RSUs or any payout thereunder, or the Company may apply to any court of appropriate jurisdiction and such application shall be a complete discharge of the liability of the Company therefor.

14.Transfer Restriction. Any Shares delivered pursuant to Section 3 hereof shall thereafter be freely transferable by the Employee, provided that the Employee agrees for himself or herself and his or her heirs, legatees and legal representatives, with respect to all Shares acquired pursuant to the terms and conditions of this Agreement (or any Shares issued pursuant to a stock dividend or stock split thereon or any securities issued in lieu thereof or in substitution or exchange therefor), that he or she and his or her heirs, legatees and legal representatives will not sell or otherwise dispose of such shares except pursuant to a registration statement filed by the Company with the Securities and Exchange Commission under the Securities Act of 1933, as amended (the “Act”), or except in a transaction which is determined by counsel to the Company to be exempt from registration under the Act and any applicable state securities laws; and to execute and deliver to the Company such investment representations and warranties, and to take such other actions, as counsel for the Company determines may be necessary or appropriate for compliance with the Act and any other applicable securities laws. The Employee agrees that any certificates representing any of the Shares acquired pursuant to the terms and conditions of this Agreement may bear such legend or legends as the Company deems appropriate in order to assure compliance with applicable securities laws.

15.Status of Employee. The Employee shall not be deemed for any purposes to be a shareowner of the Company with respect to any of the RSUs except to the extent that the Company has delivered Shares pursuant to Section 3 hereof. Therefore, the Employee will not have the right of shareowners to vote or, subject to Section 8, to receive dividends or distributions of any kind prior to the Company delivering Shares pursuant to Section 3 hereof. Neither the Plan nor the RSUs shall confer upon the Employee any right to continue as an employee of the Company or any of its Affiliates, nor to interfere in any way with the right of the Company to terminate the employment or directorship of the Employee at any time.

16.Powers of the Company Not Affected. The existence of the RSUs shall not affect in any way the right or power of the Company or its shareowners to make or authorize any or all adjustments, recapitalizations, reorganizations or other changes in the Company’s capital structure or its business, or any merger or consolidation of the Company, or any issuance of bonds, debentures, preferred or prior preference stock senior to or affecting the Shares or the rights thereof, or dissolution or liquidation of the Company, or any sale or transfer of all or any part of the Company’s assets or business or any other corporate act or proceeding, whether of a similar character or otherwise.

17.Interpretation by the Committee. As a condition of the granting of the RSUs, the Employee agrees, for himself or herself and for his or her legal representatives or guardians, that this Agreement shall be interpreted by the Committee and that any interpretation by the Committee of the terms of this Agreement and any determination made by the Committee pursuant to this Agreement shall be final, binding and conclusive.

18.Miscellaneous.

(a)This Agreement shall be governed and construed in accordance with the internal laws of the State of Wisconsin applicable to contracts made and to be performed therein between residents thereof. As a condition of the granting of the RSUs, the Employee irrevocably consents to the nonexclusive jurisdiction and venue of the state and federal courts located in the State of Wisconsin.

(b)The Plan and this Agreement set forth the entire understanding between the Company and the Employee with respect to the subject matter hereof and shall supersede in all respects, and the Employee hereby waives all rights under, any prior or other agreement or understanding between the parties with respect to such subject matter, including, but not limited to, any Key Executive Employment and Severance Agreement. For the avoidance of doubt, the Plan and this Agreement shall control in the event there is any express conflict between the Plan and this Agreement and any prior or other agreement or understanding between the parties.

(c)This Agreement may not be amended or modified except by the written consent of the parties hereto. Notwithstanding the foregoing, the Committee need not obtain Employee (or other interested party) consent for any such action: (i) to the extent the action is deemed necessary by the Committee to comply with any applicable law; (ii) to the extent the action is deemed necessary by the Committee to preserve favorable accounting or tax treatment for the Company of any Award; (iii) to the extent the Committee determines that

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such action does not materially and adversely affect the value of an Award or that such action is in the best interest of the affected Employee; or (iv) to the extent unilateral action by the Committee is permitted under Section 14(c) of the Plan.

(d)The Award and any Shares or cash issued thereunder shall be subject to potential cancellation, rescission, payback, recoupment or other action in accordance with the terms of any Company clawback policy (the “Clawback Policy”), as then in effect and as it may be amended from time to time, to the extent the Clawback Policy applies to the Award and any Shares or cash issued thereunder (including a Clawback Policy implemented or amendments made thereto after the Grant Date for the Award). By accepting the Award, the Employee agrees to execute any additional documents as may be requested by the Company to affect the Company’s application, implementation and adoption of a Clawback Policy with respect to the Award and any Shares or cash issued thereunder.

(e)The captions of this Agreement are inserted for convenience of reference only and shall not be taken into account in construing this Agreement.

IN WITNESS WHEREOF, the Company has caused this Agreement to be executed by its duly authorized officer and the Employee has hereunto affixed his or her hand as of the day and year first above written.

ALLIANT ENERGY CORPORATION
(the “Company”)

By:

Its:

EMPLOYEE:

Employee’s Signature

    ###PARTICIPANT_NAME###    
Employee’s Printed Name

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EX-10.3F

Exhibit 10.3f

FORM OF ALLIANT ENERGY CORPORATION

PERFORMANCE RESTRICTED STOCK UNIT AGREEMENT

THIS PERFORMANCE RESTRICTED STOCK UNIT AGREEMENT (this “Agreement”) is made and entered into as of this ____ day of ________ 20__ (the “Grant Date”) by and between Alliant Energy Corporation, a Wisconsin corporation (the “Company”), and ###PARTICIPANT_NAME###, a key employee of the Company (the “Employee”).

R E C I T A L S

WHEREAS, the Company has in effect the Alliant Energy Corporation 2020 Omnibus Incentive Plan (the “Plan”), the terms of which, to the extent not stated herein, are specifically incorporated by reference in this Agreement and capitalized terms used herein which are not otherwise defined shall have the meaning set forth in the Plan;

WHEREAS, one of the purposes of the Plan is to permit the grant of various equity-based incentive awards, including performance restricted stock units (“PRSUs”), to individuals selected by the Compensation and Personnel Committee of the Board of Directors of the Company (the “Committee”);

WHEREAS, the Employee is now employed by the Company or an Affiliate of the Company in a key capacity and has exhibited judgment, initiative and efforts which have contributed materially to the successful performance of the Company and/or its Affiliates; and

WHEREAS, the Company desires the Employee to remain as an employee of the Company or its Affiliates and wishes to provide the Employee with the opportunity to secure or increase their stock ownership in the Company in order to develop even a stronger incentive to put forth maximum effort for the continued success and growth of the Company.

A G R E E M E N T

NOW, THEREFORE, in consideration of the premises and of the covenants and agreements herein set forth, the parties hereby mutually covenant and agree as follows:

1.Award. Subject to the terms of this Agreement and the Plan, the Employee is hereby granted ###TOTAL_AWARDS### target PRSUs on the Grant Date. PRSUs granted under this Agreement are units that will be reflected in a book account maintained by the Company during the Performance Period set forth below, and that will be settled in Shares to the extent provided in this Agreement and the Plan.

2.Performance Period; Performance Goals.

(a)    The “Performance Period” is the period beginning on ###DATE### and ending on ###DATE###.

(b)    Except as otherwise provided in this Agreement (including Section 9 below), the PRSUs will become earned based on achievement of the requisite performance goal or performance goals (the “Performance Goals”) determined in accordance with the provisions of Exhibit 1, which is attached to and forms a part of this Agreement. Any unearned PRSUs automatically will terminate and be cancelled, without the payment of any consideration following the last day of the Performance Period.

3.Settlement of Awards. Subject to Section 9 below, the Company shall deliver to the Employee one Share for each PRSU earned by the Employee, as determined in accordance with the provisions of Exhibit 1, with fractional shares rounded up to the nearest whole share.

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4.Time of Payment. Except as otherwise provided in this Agreement (including Section 9 below), payment of PRSUs earned in accordance with the provisions of Section 3 will be delivered as soon as practicable (but in any event within 75 days) following the last day of the Performance Period set forth in Section 2(a), subject to the Committee approving in writing as to the satisfaction of the requisite Performance Goal or Goals.

5.Retirement, Disability, or Death During Performance Period and Prior to a Change in Control. If the Employee’s employment with the Company and its Affiliates terminates during the Performance Period and prior to a Change in Control because of the Employee’s Retirement (as defined below), Disability, or death, the Employee shall be entitled to the full value of the Award earned in accordance with Exhibit 1, determined at the end of the Performance Period, so long as the termination event occurs after the end of the first year of the Performance Period and only if and to the extent the Performance Goals are met. If the termination event occurs during the first year of the Performance Period, the Employee will be entitled to a prorated value of the Award, earned in accordance with Exhibit 1, determined at the end of the Performance Period and only if and to the extent the Performance Goals are met, based on a fraction, the numerator of which is the number of months the Employee was employed during the Performance Period and the denominator of which is 12.

6.Involuntary Termination Without Cause During Performance Period and Prior to a Change in Control. If the Employee’s employment with the Company and its Affiliates terminates during the Performance Period and prior to a Change in Control because of an Involuntary Termination without Cause (as defined below), the Employee shall be entitled to the prorated value of the Award earned, determined at the end of the Performance Period and only if and to the extent the Performance Goals are met, based on a fraction, the numerator of which is the number of months the Employee was employed during the Performance Period and the denominator of which is 36.

7.Other Terminations of Employment During Performance Period. If the Employee’s employment with the Company and its Affiliates terminates during the Performance Period and prior to a Change in Control for any reason other than the Employee’s Retirement, Disability, Involuntary Termination without Cause, or death, the PRSUs granted under this Agreement automatically will terminate and be cancelled on the date of such termination of employment.

8.Dividend Equivalents.

(a)    After the Performance Period has ended (or, if a Change in Control occurs during the Performance Period, the effective date of the Change in Control), dividend equivalents (“Dividend Equivalents”) will be calculated and credited to the account of the Employee with respect to the percentage of PRSUs that are earned (or payable in accordance with Section 9 in the event of a Change in Control). Dividend Equivalents will be credited as additional PRSUs, the number of which will be equal to the number of whole Shares that could be purchased with the amount of the Dividend Equivalents, based on the Fair Market Value of the Shares as of the dividend payment date and the number of earned PRSUs (or target PRSUs in accordance with Section 9 in the event of a Change in Control).

(b)    Any Dividend Equivalents credited to the Employee’s account pursuant to this Section 8 shall not be vested or paid until the dates of vesting or payment of the PRSUs with respect to which such Dividend Equivalents are credited, and such Dividend Equivalents shall be subject to the same restrictions and other terms and conditions as apply to the PRSUs with respect to which they were credited.

(c)    No Dividend Equivalents shall be credited to the Employee with respect to record dates occurring prior to the Grant Date or with respect to record dates occurring on or after the date, if any, on which the PRSUs are cancelled and terminated.

9.Change in Control.

(a)    No Termination of Employment Prior to a Change in Control.

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(i)    Notwithstanding anything to the contrary in the Plan, this Agreement, or the Employee’s employment agreement or any other agreement to which the Employee is a party, if a Change in Control occurs during the Performance Period and the Employee’s employment does not terminate before the effectiveness of the Change in Control, then the Employee shall be entitled to the target PRSUs, which automatically will convert into a contractual right to receive a cash payment (the “Cash Payment Right”) in an amount equal to (i) the number of target PRSUs (including any additional PRSUs determined in accordance with Section 8(a)), multiplied by (ii) the per Share Fair Market Value as of the trading day immediately preceding the effective date of the Change in Control. After such conversion, no interest or Dividend Equivalents will be accrued, credited or paid with respect to the Cash Payment Right. Any portion of the PRSUs that is not converted into the Cash Payment Right automatically shall terminate and be cancelled immediately prior to the effectiveness of the Change in Control, without the payment of any consideration therefor.

(ii)    Notwithstanding anything to the contrary in the Plan, this Agreement, or the Employee’s employment agreement or any other agreement to which the Employee is a party, the Cash Payment Right shall be paid as soon as practicable (but in any event within 75 days) after the last day of the Performance Period set forth in Section 2(a), provided that the Employee remains continuously employed by the Company or an Affiliate or any successor thereto through the last day of such Performance Period. Notwithstanding the immediately preceding sentence, in the event that the Employee experiences a termination of employment due to the Employee’s Retirement (as defined below), Disability, or death or an involuntary termination of employment by action of the Company (or its successor) (other than a termination due to Cause) or due to the Employee’s resignation for Good Reason prior to the last day of the Performance Period set forth in Section 2(a), the Cash Payment Right will be paid in accordance with the first sentence of this Section 9(a)(ii) as though the Employee remained continuously employed by the Company or an Affiliate or any successor thereto through the last day of the Performance Period.

(b)    Certain Terminations of Employment Prior to a Change in Control. Solely for purposes of Sections 5 and 6 of the Agreement, if the Employee’s employment terminates for any of the reasons set forth in such Sections 5 and 6 prior to a Change in Control and a Change in Control occurs during the Performance Period, then the Employee shall be entitled to the target PRSUs in lieu of any amount set forth in Section 5 or Section 6, as applicable, which PRSUs automatically shall convert into a contractual right to receive the Cash Payment Right. After such conversion, no interest or Dividend Equivalents will be accrued, credited or paid with respect to the Cash Payment Right. For the avoidance of doubt, the Cash Payment Right will be paid at such time provided under Section 4.

10.Definitions.

(a)“Involuntary Termination without Cause” shall mean that the Employee experiences a termination of employment due to the Employee’s (i) receipt of a written notification that his or her position is being eliminated as a result of a structured job elimination program or (ii) resignation for a Pre-Change in Control Good Reason.

(b)“Pre-Change in Control Good Reason” shall mean that an applicable event occurs and the Employee provides notice to the Company of the existence of the event within 90 days of the initial existence of the event, the Company fails to cure the event within 30 days of such notice and the Employee resigns within 30 days following the last day of such 30-day cure period. The applicable events are any one or more of the following: (i) a material diminution in the Employee’s base compensation and (ii) a material diminution in the Employee’s authority, duties, or responsibilities.

(c)“Retirement” shall mean the Employee’s employment terminates (with the consent of the Company) after he or she has reached age 55 and the Employee’s age, in whole years, added to the number of whole years of the Employee’s continuous employment with the Company total 65 or more.

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11.Non-transferability of PRSUs. The PRSUs shall not be assignable, alienable, saleable or transferable by the Employee other than by will or the laws of descent and distribution prior to settlement of the Awards pursuant to Section 3 (or, if applicable, Section 9); provided, however, that the Employee shall be entitled, in the manner provided in Section 13 hereof, to designate a beneficiary to receive any Shares or cash issuable with respect to the Award upon the death of the Employee.

12.Tax Withholding. The Company may deduct and withhold from any cash otherwise payable to the Employee such amount as may be required for the purpose of satisfying the Company’s obligation to withhold federal, state or local taxes. Further, in the event the amount so withheld is insufficient for such purpose, the Company may require that the Employee pay to the Company upon its demand or otherwise make arrangements satisfactory to the Company for payment of, such amount as may be requested by the Company in order to satisfy its obligation to withhold any such taxes.

Unless otherwise determined by the Company, by this Agreement, the Employee agrees that the Company shall withhold Shares otherwise issuable to the Employee (the “Withholding Election”) having a Fair Market Value on the date income is recognized (the “Tax Date”) pursuant to the settlement of the Award equal to the minimum amount required to be withheld (or such other applicable rate permitted by the Company that avoids adverse treatment for financial accounting purposes). If the number of Shares withheld to satisfy withholding tax requirements includes a fractional Share, the number of Shares withheld shall be reduced to the next lower whole number and the Employee shall deliver cash in lieu of such fractional Share, or otherwise make arrangements satisfactory to the Company for payment of such amount. Regardless of any action taken by the Company, the Employee understands that the ultimate liability for all tax-related items related to the Award is and remains the Employee’s responsibility and may exceed the amount, if any, withheld by the Company. The Employee further acknowledges that the Company (i) makes no representations or undertakings regarding the treatment of any tax-related items in connection with any aspect of the Award, including, but not limited to, the grant, vesting or settlement of the Award, the subsequent sale of Shares acquired pursuant to the Award, or the receipt of any dividends and/or Dividend Equivalents and (ii) does not commit to and is under no obligation to structure the terms of the grant or any other aspect of the Award to reduce or eliminate the Employee’s liability for tax-related items related to the Award or achieve any particular tax result.

13.Designation of Beneficiary. The Employee shall be permitted to designate one or more beneficiaries (each, a “Beneficiary”) on a Company-approved form who shall be entitled to payouts hereunder, to the extent payouts are made, after the death of the Employee. The terms and conditions of any such designation (including any changes thereto by the Employee) shall be subject to the terms and conditions of such Company-approved beneficiary designation form. If no such beneficiary designation is in effect at the time of the Employee’s death, or if no designated Beneficiary survives the Employee or if such designation conflicts with law, the Employee’s estate acting through his or her legal representative shall be entitled to receive payouts hereunder, to the extent they are made, after the death of the Employee. If the Committee is in doubt as to the right of any person to the PRSUs or any payout thereunder, the Company may refuse to settle such matter, without liability for any interest or dividends on the PRSUs, until the Committee determines the person entitled to the PRSUs or any payout thereunder, or the Company may apply to any court of appropriate jurisdiction and such application shall be a complete discharge of the liability of the Company therefor.

14.Transfer Restriction. Any Shares delivered pursuant to Section 3 hereof shall thereafter be freely transferable by the Employee, provided that the Employee agrees for himself or herself and his or her heirs, legatees and legal representatives, with respect to all Shares acquired pursuant to the terms and conditions of this Agreement (or any Shares issued pursuant to a stock dividend or stock split thereon or any securities issued in lieu thereof or in substitution or exchange therefor), that he or she and his or her heirs, legatees and legal representatives will not sell or otherwise dispose of such shares except pursuant to a registration statement filed by the Company with the Securities and Exchange Commission under the Securities Act of 1933, as amended (the “Act”), or except in a transaction which is determined by counsel to the Company to be exempt from registration under the Act and any applicable state securities laws; and to execute and deliver to the Company such investment representations and warranties, and to take such other actions, as counsel for the Company determines may be necessary or appropriate for compliance with the Act and any other applicable securities laws. The Employee agrees that any certificates representing any of the Shares acquired pursuant to the terms and conditions of this Agreement may bear such legend or legends as the Company deems appropriate in order to assure compliance with applicable securities laws.

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15.Status of Employee. The Employee shall not be deemed for any purposes to be a shareowner of the Company with respect to any of the PRSUs except to the extent that the Company has delivered Shares pursuant to Section 3 hereof. Therefore, the Employee will not have the right of shareowners to vote or, subject to Section 8, to receive dividends or distributions of any kind prior to the Company delivering Shares pursuant to Section 3 hereof. Neither the Plan nor the PRSUs shall confer upon the Employee any right to continue as an employee of the Company or any of its Affiliates, nor to interfere in any way with the right of the Company to terminate the employment or directorship of the Employee at any time.

16.Powers of the Company Not Affected. The existence of the PRSUs shall not affect in any way the right or power of the Company or its shareowners to make or authorize any or all adjustments, recapitalizations, reorganizations or other changes in the Company’s capital structure or its business, or any merger or consolidation of the Company, or any issuance of bonds, debentures, preferred or prior preference stock senior to or affecting the Shares or the rights thereof, or dissolution or liquidation of the Company, or any sale or transfer of all or any part of the Company’s assets or business or any other corporate act or proceeding, whether of a similar character or otherwise.

17.Interpretation by the Committee. As a condition of the granting of the PRSUs, the Employee agrees, for himself or herself and for his or her legal representatives or guardians, that this Agreement shall be interpreted by the Committee and that any interpretation by the Committee of the terms of this Agreement and any determination made by the Committee pursuant to this Agreement shall be final, binding and conclusive.

18.Miscellaneous.

(a)This Agreement shall be governed and construed in accordance with the internal laws of the State of Wisconsin applicable to contracts made and to be performed therein between residents thereof. As a condition of the granting of the PRSUs, the Employee irrevocably consents to the nonexclusive jurisdiction and venue of the state and federal courts located in the State of Wisconsin.

(b)The Plan and this Agreement set forth the entire understanding between the Company and the Employee with respect to the subject matter hereof and shall supersede in all respects, and the Employee hereby waives all rights under, any prior or other agreement or understanding between the parties with respect to such subject matter, including, but not limited to, any Key Executive Employment and Severance Agreement. For the avoidance of doubt, the Plan and this Agreement shall control in the event there is any express conflict between the Plan and this Agreement and any prior or other agreement or understanding between the parties.

(c)This Agreement may not be amended or modified except by the written consent of the parties hereto. Notwithstanding the foregoing, the Committee need not obtain Employee (or other interested party) consent for any such action: (i) to the extent the action is deemed necessary by the Committee to comply with any applicable law; (ii) to the extent the action is deemed necessary by the Committee to preserve favorable accounting or tax treatment for the Company of any Award; (iii) to the extent the Committee determines that such action does not materially and adversely affect the value of an Award or that such action is in the best interest of the affected Employee; or (iv) to the extent unilateral action by the Committee is permitted under Section 14(c) of the Plan.

(d)The Award and any Shares or cash issued thereunder shall be subject to potential cancellation, rescission, payback, recoupment or other action in accordance with the terms of any Company clawback policy (the “Clawback Policy”), as then in effect and as it may be amended from time to time, to the extent the Clawback Policy applies to the Award and any Shares or cash issued thereunder (including a Clawback Policy implemented or amendments made thereto after the Grant Date for the Award). By accepting the PRSUs, the Employee agrees to execute any additional documents as may be requested by the Company to affect the Company’s application, implementation and adoption of a Clawback Policy with respect to the Award and any Shares or cash issued thereunder.

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(e)The captions of this Agreement are inserted for convenience of reference only and shall not be taken into account in construing this Agreement.

* * *

[The signatures to this Agreement are on the next page.]

2022 Performance Restricted Stock Unit Diversity Metric 6

IN WITNESS WHEREOF, the Company has caused this Agreement to be executed by its duly authorized officer and the Employee has hereunto affixed his or her hand as of the day and year first above written.

ALLIANT ENERGY CORPORATION
(the “Company”)

By:

Its:

EMPLOYEE:

Employee’s Signature

    ###PARTICIPANT_NAME###    
Employee’s Printed Name

2022 Performance Restricted Stock Unit Diversity Metric 7

EXHIBIT 1

PERFORMANCE RESTRICTED STOCK UNIT GRANT - PERFORMANCE GOALS

1.    Purpose: The purpose of this Exhibit 1 is to set forth the Performance Goal or Goals that will be applied to determine the amount of the Award that will be earned under the terms of the attached Performance Restricted Stock Unit Agreement (the “Agreement”). This Exhibit 1 is incorporated into and forms a part of the Agreement.

PARTICIPANT_NAME	20__
Grant Date	###GRANT_DATE###
Grant Date Fair Market Value	###MARKET_PRICE_AT_TIME_OF_GRANT###
PRSUs (Target)	###TOTAL_AWARDS###
Performance Period	###DATE### through ###DATE###

2.    Performance Goal: The Award will be based on the Company’s workforce representation of (i) people of color and (ii) women measured at the end of the performance period, with each Performance Goal equally weighted and determined independently of the other.

3.    Amount of Award: Actual awards will be based on Company performance as specified above and can range from 0 to 200 percent of target PRSUs granted based on the achievement level of each Performance Goal below. Subject to Section 9 of the Agreement, the number of PRSUs earned by the Employee shall be determined in accordance with the following schedule, with the sum of the applicable percentages of target PRSUs earned under each Performance Goal resulting in the final payout percentage of the Award:

Workforce Representation of People of Color (50% Weight)	Percentage of Target PRSUs Earned
___%	___%
___%	___%
___%	___%

Workforce Representation of Women (50% Weight)	Percentage of Target PRSUs Earned
___%	___%
___%	___%
___%	___%

PRSUs will be prorated for achievement of performance between the performance targets: If achievement of a Performance Goal is between any two data points, the corresponding percentage of PRSUs earned shall be determined by interpolation between the corresponding data points.

2022 Performance Restricted Stock Unit Diversity Metric 8

EX-10.3G

Exhibit 10.3g

FORM OF ALLIANT ENERGY CORPORATION

PERFORMANCE RESTRICTED STOCK UNIT AGREEMENT

THIS PERFORMANCE RESTRICTED STOCK UNIT AGREEMENT (this “Agreement”) is made and entered into as of this ____ day of ________ 20__ (the “Grant Date”) by and between Alliant Energy Corporation, a Wisconsin corporation (the “Company”), and ###PARTICIPANT_NAME###, a key employee of the Company (the “Employee”).

R E C I T A L S

WHEREAS, the Company has in effect the Alliant Energy Corporation 2020 Omnibus Incentive Plan (the “Plan”), the terms of which, to the extent not stated herein, are specifically incorporated by reference in this Agreement and capitalized terms used herein which are not otherwise defined shall have the meaning set forth in the Plan;

WHEREAS, one of the purposes of the Plan is to permit the grant of various equity-based incentive awards, including performance restricted stock units (“PRSUs”), to individuals selected by the Compensation and Personnel Committee of the Board of Directors of the Company (the “Committee”);

WHEREAS, the Employee is now employed by the Company or an Affiliate of the Company in a key capacity and has exhibited judgment, initiative and efforts which have contributed materially to the successful performance of the Company and/or its Affiliates; and

WHEREAS, the Company desires the Employee to remain as an employee of the Company or its Affiliates and wishes to provide the Employee with the opportunity to secure or increase their stock ownership in the Company in order to develop even a stronger incentive to put forth maximum effort for the continued success and growth of the Company.

A G R E E M E N T

NOW, THEREFORE, in consideration of the premises and of the covenants and agreements herein set forth, the parties hereby mutually covenant and agree as follows:

1.Award. Subject to the terms of this Agreement and the Plan, the Employee is hereby granted ###TOTAL_AWARDS### target PRSUs on the Grant Date. PRSUs granted under this Agreement are units that will be reflected in a book account maintained by the Company during the Performance Period set forth below, and that will be settled in Shares to the extent provided in this Agreement and the Plan.

2.Performance Period; Performance Goals.

(a)    The “Performance Period” is the period beginning on ###DATE### and ending on ###DATE###.

(b)    Except as otherwise provided in this Agreement (including Section 9 below), the PRSUs will become earned based on achievement of the requisite performance goal or performance goals (the “Performance Goals”) determined in accordance with the provisions of Exhibit 1, which is attached to and forms a part of this Agreement. Any unearned PRSUs automatically will terminate and be cancelled, without the payment of any consideration following the last day of the Performance Period.

3.Settlement of Awards. Subject to Section 9 below, the Company shall deliver to the Employee one Share for each PRSU earned by the Employee, as determined in accordance with the provisions of Exhibit 1, with fractional shares rounded up to the nearest whole share.

2022 Performance Restricted Stock Unit Net Income Metric 1

4.Time of Payment. Except as otherwise provided in this Agreement (including Section 9 below), payment of PRSUs earned in accordance with the provisions of Section 3 will be delivered as soon as practicable (but in any event within 75 days) following the last day of the Performance Period set forth in Section 2(a), subject to the Committee approving in writing as to the satisfaction of the requisite Performance Goal or Goals.

5.Retirement, Disability, or Death During Performance Period and Prior to a Change in Control. If the Employee’s employment with the Company and its Affiliates terminates during the Performance Period and prior to a Change in Control because of the Employee’s Retirement (as defined below), Disability, or death, the Employee shall be entitled to the full value of the Award earned in accordance with Exhibit 1, determined at the end of the Performance Period, so long as the termination event occurs after the end of the first year of the Performance Period and only if and to the extent the Performance Goals are met. If the termination event occurs during the first year of the Performance Period, the Employee will be entitled to a prorated value of the Award, earned in accordance with Exhibit 1, determined at the end of the Performance Period and only if and to the extent the Performance Goals are met, based on a fraction, the numerator of which is the number of months the Employee was employed during the Performance Period and the denominator of which is 12.

6.Involuntary Termination Without Cause During Performance Period and Prior to a Change in Control. If the Employee’s employment with the Company and its Affiliates terminates during the Performance Period and prior to a Change in Control because of an Involuntary Termination without Cause (as defined below), the Employee shall be entitled to the prorated value of the Award earned, determined at the end of the Performance Period and only if and to the extent the Performance Goals are met, based on a fraction, the numerator of which is the number of months the Employee was employed during the Performance Period and the denominator of which is 36.

7.Other Terminations of Employment During Performance Period. If the Employee’s employment with the Company and its Affiliates terminates during the Performance Period and prior to a Change in Control for any reason other than the Employee’s Retirement, Disability, Involuntary Termination without Cause, or death, the PRSUs granted under this Agreement automatically will terminate and be cancelled on the date of such termination of employment.

8.Dividend Equivalents.

(a)    After the Performance Period has ended (or, if a Change in Control occurs during the Performance Period, the effective date of the Change in Control), dividend equivalents (“Dividend Equivalents”) will be calculated and credited to the account of the Employee with respect to the percentage of PRSUs that are earned (or payable in accordance with Section 9 in the event of a Change in Control). Dividend Equivalents will be credited as additional PRSUs, the number of which will be equal to the number of whole Shares that could be purchased with the amount of the Dividend Equivalents, based on the Fair Market Value of the Shares as of the dividend payment date and the number of earned PRSUs (or target PRSUs in accordance with Section 9 in the event of a Change in Control).

(b)    Any Dividend Equivalents credited to the Employee’s account pursuant to this Section 8 shall not be vested or paid until the dates of vesting or payment of the PRSUs with respect to which such Dividend Equivalents are credited, and such Dividend Equivalents shall be subject to the same restrictions and other terms and conditions as apply to the PRSUs with respect to which they were credited.

(c)    No Dividend Equivalents shall be credited to the Employee with respect to record dates occurring prior to the Grant Date or with respect to record dates occurring on or after the date, if any, on which the PRSUs are cancelled and terminated.

9.Change in Control.

(a)    No Termination of Employment Prior to a Change in Control.

(i)    Notwithstanding anything to the contrary in the Plan, this Agreement, or the Employee’s employment agreement or any other agreement to which the Employee is a party, if a Change in

2022 Performance Restricted Stock Unit Net Income Metric 2

Control occurs during the Performance Period and the Employee’s employment does not terminate before the effectiveness of the Change in Control, then the Employee shall be entitled to the target PRSUs, which automatically will convert into a contractual right to receive a cash payment (the “Cash Payment Right”) in an amount equal to (i) the number of target PRSUs (including any additional PRSUs determined in accordance with Section 8(a)), multiplied by (ii) the per Share Fair Market Value as of the trading day immediately preceding the effective date of the Change in Control. After such conversion, no interest or Dividend Equivalents will be accrued, credited or paid with respect to the Cash Payment Right. Any portion of the PRSUs that is not converted into the Cash Payment Right automatically shall terminate and be cancelled immediately prior to the effectiveness of the Change in Control, without the payment of any consideration therefore.

(ii)    Notwithstanding anything to the contrary in the Plan, this Agreement, or the Employee’s employment agreement or any other agreement to which the Employee is a party, the Cash Payment Right shall be paid as soon as practicable (but in any event within 75 days) after the last day of the Performance Period set forth in Section 2(a), provided that the Employee remains continuously employed by the Company or an Affiliate or any successor thereto through the last day of such Performance Period. Notwithstanding the immediately preceding sentence, in the event that the Employee experiences a termination of employment due to the Employee’s Retirement (as defined below), Disability, or death or an involuntary termination of employment by action of the Company (or its successor) (other than a termination due to Cause) or due to the Employee’s resignation for Good Reason prior to the last day of the Performance Period set forth in Section 2(a), the Cash Payment Right will be paid in accordance with the first sentence of this Section 9(a)(ii) as though the Employee remained continuously employed by the Company or an Affiliate or any successor thereto through the last day of the Performance Period.

(b)    Certain Terminations of Employment Prior to a Change in Control. Solely for purposes of Sections 5 and 6 of the Agreement, if the Employee’s employment terminates for any of the reasons set forth in such Sections 5 and 6 prior to a Change in Control and a Change in Control occurs during the Performance Period, then the Employee shall be entitled to the target PRSUs in lieu of any amount set forth in Section 5 or Section 6, as applicable, which PRSUs automatically shall convert into a contractual right to receive the Cash Payment Right. After such conversion, no interest or Dividend Equivalents will be accrued, credited or paid with respect to the Cash Payment Right. For the avoidance of doubt, the Cash Payment Right will be paid at such time provided under Section 4.

10.Definitions.

(a)“Involuntary Termination without Cause” shall mean that the Employee experiences a termination of employment due to the Employee’s (i) receipt of a written notification that his or her position is being eliminated as a result of a structured job elimination program or (ii) resignation for a Pre-Change in Control Good Reason.

(b)“Pre-Change in Control Good Reason” shall mean that an applicable event occurs and the Employee provides notice to the Company of the existence of the event within 90 days of the initial existence of the event, the Company fails to cure the event within 30 days of such notice and the Employee resigns within 30 days following the last day of such 30-day cure period. The applicable events are any one or more of the following: (i) a material diminution in the Employee’s base compensation and (ii) a material diminution in the Employee’s authority, duties, or responsibilities.

(c)“Retirement” shall mean the Employee’s employment terminates (with the consent of the Company) after he or she has reached age 55 and the Employee’s age, in whole years, added to the number of whole years of the Employee’s continuous employment with the Company total 65 or more.

11.Non-transferability of PRSUs. The PRSUs shall not be assignable, alienable, saleable or transferable by the Employee other than by will or the laws of descent and distribution prior to settlement of the Awards pursuant to Section 3 (or, if applicable, Section 9); provided, however, that the Employee shall be entitled, in the manner provided in Section 13 hereof, to designate a beneficiary to receive any Shares or cash issuable with respect to the Award upon the death of the Employee.

2022 Performance Restricted Stock Unit Net Income Metric 3

12.Tax Withholding. The Company may deduct and withhold from any cash otherwise payable to the Employee such amount as may be required for the purpose of satisfying the Company’s obligation to withhold federal, state or local taxes. Further, in the event the amount so withheld is insufficient for such purpose, the Company may require that the Employee pay to the Company upon its demand or otherwise make arrangements satisfactory to the Company for payment of, such amount as may be requested by the Company in order to satisfy its obligation to withhold any such taxes.

Unless otherwise determined by the Company, by this Agreement, the Employee agrees that the Company shall withhold Shares otherwise issuable to the Employee (the “Withholding Election”) having a Fair Market Value on the date income is recognized (the “Tax Date”) pursuant to the settlement of the Award equal to the minimum amount required to be withheld (or such other applicable rate permitted by the Company that avoids adverse treatment for financial accounting purposes). If the number of Shares withheld to satisfy withholding tax requirements includes a fractional Share, the number of Shares withheld shall be reduced to the next lower whole number and the Employee shall deliver cash in lieu of such fractional Share, or otherwise make arrangements satisfactory to the Company for payment of such amount. Regardless of any action taken by the Company, the Employee understands that the ultimate liability for all tax-related items related to the Award is and remains the Employee’s responsibility and may exceed the amount, if any, withheld by the Company. The Employee further acknowledges that the Company (i) makes no representations or undertakings regarding the treatment of any tax-related items in connection with any aspect of the Award, including, but not limited to, the grant, vesting or settlement of the Award, the subsequent sale of Shares acquired pursuant to the Award, or the receipt of any dividends and/or Dividend Equivalents and (ii) does not commit to and is under no obligation to structure the terms of the grant or any other aspect of the Award to reduce or eliminate the Employee’s liability for tax-related items related to the Award or achieve any particular tax result.

13.Designation of Beneficiary. The Employee shall be permitted to designate one or more beneficiaries (each, a “Beneficiary”) on a Company-approved form who shall be entitled to payouts hereunder, to the extent payouts are made, after the death of the Employee. The terms and conditions of any such designation (including any changes thereto by the Employee) shall be subject to the terms and conditions of such Company-approved beneficiary designation form. If no such beneficiary designation is in effect at the time of the Employee’s death, or if no designated Beneficiary survives the Employee or if such designation conflicts with law, the Employee’s estate acting through his or her legal representative shall be entitled to receive payouts hereunder, to the extent they are made, after the death of the Employee. If the Committee is in doubt as to the right of any person to the PRSUs or any payout thereunder, the Company may refuse to settle such matter, without liability for any interest or dividends on the PRSUs, until the Committee determines the person entitled to the PRSUs or any payout thereunder, or the Company may apply to any court of appropriate jurisdiction and such application shall be a complete discharge of the liability of the Company therefor.

14.Transfer Restriction. Any Shares delivered pursuant to Section 3 hereof shall thereafter be freely transferable by the Employee, provided that the Employee agrees for himself or herself and his or her heirs, legatees and legal representatives, with respect to all Shares acquired pursuant to the terms and conditions of this Agreement (or any Shares issued pursuant to a stock dividend or stock split thereon or any securities issued in lieu thereof or in substitution or exchange therefor), that he or she and his or her heirs, legatees and legal representatives will not sell or otherwise dispose of such shares except pursuant to a registration statement filed by the Company with the Securities and Exchange Commission under the Securities Act of 1933, as amended (the “Act”), or except in a transaction which is determined by counsel to the Company to be exempt from registration under the Act and any applicable state securities laws; and to execute and deliver to the Company such investment representations and warranties, and to take such other actions, as counsel for the Company determines may be necessary or appropriate for compliance with the Act and any other applicable securities laws. The Employee agrees that any certificates representing any of the Shares acquired pursuant to the terms and conditions of this Agreement may bear such legend or legends as the Company deems appropriate in order to assure compliance with applicable securities laws.

15.Status of Employee. The Employee shall not be deemed for any purposes to be a shareowner of the Company with respect to any of the PRSUs except to the extent that the Company has delivered Shares pursuant to Section 3 hereof. Therefore, the Employee will not have the right of shareowners to vote or, subject to Section 8, to receive dividends or distributions of any kind prior to the Company delivering Shares pursuant to Section 3 hereof. Neither the Plan nor the PRSUs shall confer upon the Employee any right to

2022 Performance Restricted Stock Unit Net Income Metric 4

continue as an employee of the Company or any of its Affiliates, nor to interfere in any way with the right of the Company to terminate the employment or directorship of the Employee at any time.

16.Powers of the Company Not Affected. The existence of the PRSUs shall not affect in any way the right or power of the Company or its shareowners to make or authorize any or all adjustments, recapitalizations, reorganizations or other changes in the Company’s capital structure or its business, or any merger or consolidation of the Company, or any issuance of bonds, debentures, preferred or prior preference stock senior to or affecting the Shares or the rights thereof, or dissolution or liquidation of the Company, or any sale or transfer of all or any part of the Company’s assets or business or any other corporate act or proceeding, whether of a similar character or otherwise.

17.Interpretation by the Committee. As a condition of the granting of the PRSUs, the Employee agrees, for himself or herself and for his or her legal representatives or guardians, that this Agreement shall be interpreted by the Committee and that any interpretation by the Committee of the terms of this Agreement and any determination made by the Committee pursuant to this Agreement shall be final, binding and conclusive.

18.Miscellaneous.

(a)This Agreement shall be governed and construed in accordance with the internal laws of the State of Wisconsin applicable to contracts made and to be performed therein between residents thereof. As a condition of the granting of the PRSUs, the Employee irrevocably consents to the nonexclusive jurisdiction and venue of the state and federal courts located in the State of Wisconsin.

(b)The Plan and this Agreement set forth the entire understanding between the Company and the Employee with respect to the subject matter hereof and shall supersede in all respects, and the Employee hereby waives all rights under, any prior or other agreement or understanding between the parties with respect to such subject matter, including, but not limited to, any Key Executive Employment and Severance Agreement. For the avoidance of doubt, the Plan and this Agreement shall control in the event there is any express conflict between the Plan and this Agreement and any prior or other agreement or understanding between the parties.

(c)This Agreement may not be amended or modified except by the written consent of the parties hereto. Notwithstanding the foregoing, the Committee need not obtain Employee (or other interested party) consent for any such action: (i) to the extent the action is deemed necessary by the Committee to comply with any applicable law; (ii) to the extent the action is deemed necessary by the Committee to preserve favorable accounting or tax treatment for the Company of any Award; (iii) to the extent the Committee determines that such action does not materially and adversely affect the value of an Award or that such action is in the best interest of the affected Employee; or (iv) to the extent unilateral action by the Committee is permitted under Section 14(c) of the Plan.

(d)The Award and any Shares or cash issued thereunder shall be subject to potential cancellation, rescission, payback, recoupment or other action in accordance with the terms of any Company clawback policy (the “Clawback Policy”), as then in effect and as it may be amended from time to time, to the extent the Clawback Policy applies to the Award and any Shares or cash issued thereunder (including a Clawback Policy implemented or amendments made thereto after the Grant Date for the Award). By accepting the PRSUs, the Employee agrees to execute any additional documents as may be requested by the Company to affect the Company’s application, implementation and adoption of a Clawback Policy with respect to the Award and any Shares or cash issued thereunder.

(e)The captions of this Agreement are inserted for convenience of reference only and shall not be taken into account in construing this Agreement.

* * *

[The signatures to this Agreement are on the next page.]

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IN WITNESS WHEREOF, the Company has caused this Agreement to be executed by its duly authorized officer and the Employee has hereunto affixed his or her hand as of the day and year first above written.

ALLIANT ENERGY CORPORATION
(the “Company”)

By:

Its:

EMPLOYEE:

Employee’s Signature

    ###PARTICIPANT_NAME###    
Employee’s Printed Name

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EXHIBIT 1

PERFORMANCE RESTRICTED STOCK UNIT GRANT - PERFORMANCE GOALS

1.    Purpose: The purpose of this Exhibit 1 is to set forth the Performance Goal or Goals that will be applied to determine the amount of the Award that will be earned under the terms of the attached Performance Restricted Stock Unit Agreement (the “Agreement”). This Exhibit 1 is incorporated into and forms a part of the Agreement.

PARTICIPANT_NAME	20__
Grant Date	###GRANT_DATE###
Grant Date Fair Market Value	###MARKET_PRICE_AT_TIME_OF_GRANT###
PRSUs (Target)	###TOTAL_AWARDS###
Performance Period	###DATE### through ###DATE###

2.    Performance Goal: The Award will be based on the Company’s cumulative consolidated Net Income from Continuing Operations during the performance period (“Cumulative ConsolidatedNet Income from Continuing Operations”). To determine whether the Performance Goal is satisfied, Net Income from Continuing Operations will be calculated excluding the effects of the following, if the amount is over $4,000,000 on a pre-tax basis and is not considered in the annual budget approved by the Board: (i) charges for reorganizing and restructuring; (ii) discontinued operations; (iii) asset write-downs; (iv) gains or losses on the disposition of an asset or business; (v) mergers, acquisitions or dispositions; and (vi) extraordinary, unusual and/or non-recurring items of gain or loss, that in all of the foregoing the Company identifies in its audited financial statements, including notes to the financial statements (i.e., footnotes), or the Management’s Discussion and Analysis section of the Company’s periodic reports.

3.    Amount of Award: Actual awards will be based on Company performance as specified above and can range from 0 to 200 percent of target PRSUs granted. Subject to Section 9 of the Agreement, the number of PRSUs earned by the Employee shall be determined in accordance with the following schedule:

Cumulative Consolidated Net Income from Continuing Operations (Millions)	Percentage of Target PRSUs Earned
$____ or Greater	___%
$____	___%
$____	___%
Below $____	___%

PRSUs will be prorated for achievement of performance between the performance targets: If Cumulative Net Income from Continuing Operations is between any two data points, the corresponding percentage of PRSUs earned shall be determined by interpolation between the corresponding data points.

2022 Performance Restricted Stock Unit Net Income Metric 7

EX-10.14

Exhibit 10.14

ALLIANT ENERGY CORPORATION

INTERSTATE POWER AND LIGHT COMPANY

WISCONSIN POWER AND LIGHT COMPANY

Summary of Compensation and Benefits for

Non-Employee Directors

Effective January 1, 2022

Effective January 1, 2022, the aggregate compensation for non-employee members of the Board of Directors (the “Board”) of Alliant Energy Corporation, Interstate Power and Light Company and Wisconsin Power and Light Company will be as follows:

Non-employee members of the Board will be entitled to receive the following annual retainers as applicable:

•$260,000 for each non-employee director;

•$30,000 for the Lead Independent Director of the Board;

•$20,000 for the Chairperson of each the Audit Committee and the Compensation and Personnel Committee of the Board;

•$5,000 for each member of the Audit Committee of the Board other than the Chairperson;

•$15,000 for the Chairperson of each the Nominating and Governance Committee and the Operations Committee of the Board.

Payments of all retainers shall be in cash and shall be paid quarterly in advance.

Each director may, and is encouraged to, voluntarily elect an amount of any of the cash compensation retainers to purchase common stock of Alliant Energy Corporation under the Shareowner Direct Plan or to have an amount be deferred in the Alliant Energy Deferred Compensation Plan Stock Account.

Alliant Energy Corporation maintains a Director’s Charitable Award Program for directors who were elected or appointed to the Board on or prior to January 1, 2005. Under the Program, when a director dies, Alliant Energy Corporation will donate a total of $500,000 to one qualified charitable organization or divide that amount among a maximum of five qualified charitable organizations selected by the individual director. All deductions for charitable contributions are taken by Alliant Energy Corporation, and the donations are funded by Alliant Energy Corporation through life insurance policies on the directors.

Directors are eligible to participate in the Alliant Energy matching gift programs, which are generally available to all eligible employees and/or retirees. Under these programs, Alliant Energy or the Alliant Energy Foundation provides matching funds to eligible charities based on contributions from the Directors.

Directors are reimbursed for travel and other necessary expenses incurred in the performance of their responsibilities as members of the Board of Directors.

EX-21.1

Exhibit 21.1

ALLIANT ENERGY CORPORATION

SUBSIDIARIES OF THE REGISTRANT

The following are deemed to be significant subsidiaries of Alliant Energy Corporation as of December 31, 2021:

Name of Subsidiary	State of Incorporation
Interstate Power and Light Company	Iowa
Wisconsin Power and Light Company	Wisconsin

EX-23.1

Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in Registration Statement Nos. 333-238690, 333-230331, 333-211148, 333-168812, 333-117654, and 333-51126 on Form S-8 and Registration Statement Nos. 333-251353 and 333-249909 on Form S-3 of our reports dated February 18, 2022, relating to the consolidated financial statements of Alliant Energy Corporation and subsidiaries (the “Company”), and the effectiveness of the Company’s internal control over financial reporting, appearing in this Annual Report on Form 10-K of Alliant Energy Corporation for the year ended December 31, 2021.

/s/ DELOITTE & TOUCHE LLP

Milwaukee, Wisconsin

February 18, 2022

EX-23.2

Exhibit 23.2

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in Registration Statement No. 333-251353-01 on Form S-3 of our report dated February 18, 2022, relating to the consolidated financial statements of Interstate Power and Light Company and subsidiaries appearing in this Annual Report on Form 10-K of Interstate Power and Light Company for the year ended December 31, 2021.

/s/ DELOITTE & TOUCHE LLP

Milwaukee, Wisconsin

February 18, 2022

EX-23.3

Exhibit 23.3

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in Registration Statement No. 333-251353-02 on Form S-3 of our report dated February 18, 2022, relating to the consolidated financial statements of Wisconsin Power and Light Company and subsidiary appearing in this Annual Report on Form 10-K of Wisconsin Power and Light Company for the year ended December 31, 2021.

/s/ DELOITTE & TOUCHE LLP

Milwaukee, Wisconsin

February 18, 2022

EX-31.1

Exhibit 31.1

Certification of the Chief Executive Officer for Alliant Energy Corporation

I, John O. Larsen, certify that:

1.I have reviewed this annual report on Form 10-K of Alliant Energy Corporation;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5.The registrant’s other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: February 18, 2022

/s/ John O. Larsen

John O. Larsen

Chair, President and Chief Executive Officer

EX-31.2

Exhibit 31.2

Certification of the Chief Financial Officer for Alliant Energy Corporation

I, Robert J. Durian, certify that:

1.I have reviewed this annual report on Form 10-K of Alliant Energy Corporation;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5.The registrant’s other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: February 18, 2022

/s/ Robert J. Durian

Robert J. Durian

Executive Vice President and Chief Financial Officer

EX-31.3

Exhibit 31.3

Certification of the Chief Executive Officer for Interstate Power and Light Company

I, John O. Larsen, certify that:

1.I have reviewed this annual report on Form 10-K of Interstate Power and Light Company;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5.The registrant’s other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: February 18, 2022

/s/ John O. Larsen

John O. Larsen

Chair and Chief Executive Officer

EX-31.4

Exhibit 31.4

Certification of the Chief Financial Officer for Interstate Power and Light Company

I, Robert J. Durian, certify that:

1.I have reviewed this annual report on Form 10-K of Interstate Power and Light Company;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5.The registrant’s other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: February 18, 2022

/s/ Robert J. Durian

Robert J. Durian

Executive Vice President and Chief Financial Officer

EX-31.5

Exhibit 31.5

Certification of the Chief Executive Officer for Wisconsin Power and Light Company

I, John O. Larsen, certify that:

1.I have reviewed this annual report on Form 10-K of Wisconsin Power and Light Company;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5.The registrant’s other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: February 18, 2022

/s/ John O. Larsen

John O. Larsen

Chair and Chief Executive Officer

EX-31.6

Exhibit 31.6

Certification of the Chief Financial Officer for Wisconsin Power and Light Company

I, Robert J. Durian, certify that:

1.I have reviewed this annual report on Form 10-K of Wisconsin Power and Light Company;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5.The registrant’s other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: February 18, 2022

/s/ Robert J. Durian

Robert J. Durian

Executive Vice President and Chief Financial Officer

EX-32.1

Exhibit 32.1

Written Statement of the Chief Executive Officer and Chief Financial Officer

Pursuant to 18 U.S.C. §1350

Solely for the purposes of complying with 18 U.S.C. §1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, we, the undersigned Chief Executive Officer and Chief Financial Officer of Alliant Energy Corporation (the “Company”), hereby certify, based on our knowledge, that the Annual Report on Form 10-K of the Company for the year ended December 31, 2021 (the “Report”) fully complies with the requirements of Section 13(a) of the Securities Exchange Act of 1934 and that information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ John O. Larsen

John O. Larsen

Chair, President and Chief Executive Officer

/s/ Robert J. Durian

Robert J. Durian

Executive Vice President and Chief Financial Officer

February 18, 2022

EX-32.2

Exhibit 32.2

Written Statement of the Chief Executive Officer and Chief Financial Officer

Pursuant to 18 U.S.C. §1350

Solely for the purposes of complying with 18 U.S.C. §1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, we, the undersigned Chief Executive Officer and Chief Financial Officer of Interstate Power and Light Company (the “Company”), hereby certify, based on our knowledge, that the Annual Report on Form 10-K of the Company for the year ended December 31, 2021 (the “Report”) fully complies with the requirements of Section 13(a) of the Securities Exchange Act of 1934 and that information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ John O. Larsen

John O. Larsen

Chair and Chief Executive Officer

/s/ Robert J. Durian

Robert J. Durian

Executive Vice President and Chief Financial Officer

February 18, 2022

EX-32.3

Exhibit 32.3

Written Statement of the Chief Executive Officer and Chief Financial Officer

Pursuant to 18 U.S.C. §1350

Solely for the purposes of complying with 18 U.S.C. §1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, we, the undersigned Chief Executive Officer and Chief Financial Officer of Wisconsin Power and Light Company (the “Company”), hereby certify, based on our knowledge, that the Annual Report on Form 10-K of the Company for the year ended December 31, 2021 (the “Report”) fully complies with the requirements of Section 13(a) of the Securities Exchange Act of 1934 and that information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ John O. Larsen

John O. Larsen

Chair and Chief Executive Officer

/s/ Robert J. Durian

Robert J. Durian

Executive Vice President and Chief Financial Officer

February 18, 2022

XML

Document And Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Jan. 31, 2022	Jun. 30, 2021
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Document Transition Report	false
Entity Registrant Name	ALLIANT ENERGY CORP
Entity Central Index Key	0000352541
Entity Incorporation, State or Country Code	WI
Entity Address, Address Line One	4902 N. Biltmore Lane
Entity Address, City or Town	Madison
Entity Address, State or Province	WI
Entity Address, Postal Zip Code	53718
City Area Code	608
Local Phone Number	458-3311
Entity File Number	1-9894
Entity Tax Identification Number	39-1380265
Title of 12(b) Security	Common Stock, $0.01 Par Value
Trading Symbol	LNT
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 13,900.0
Entity Common Stock, Shares Outstanding		250,478,681
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Documents Incorporated by Reference	Portions of the Proxy Statement relating to Alliant Energy Corporation’s 2022 Annual Meeting of Shareowners are, or will be upon filing with the Securities and Exchange Commission, incorporated by reference into Part III hereof.
Auditor Name	DELOITTE & TOUCHE LLP
Auditor Location	Milwaukee, Wisconsin
Auditor Firm ID	34
IPL [Member]
Entity Information [Line Items]
Entity Registrant Name	INTERSTATE POWER & LIGHT CO
Entity Central Index Key	0000052485
Entity Incorporation, State or Country Code	IA
Entity Address, Address Line One	Alliant Energy Tower
Entity Address, City or Town	Cedar Rapids
Entity Address, State or Province	IA
Entity Address, Postal Zip Code	52401
City Area Code	319
Local Phone Number	786-4411
Entity File Number	1-4117
Entity Tax Identification Number	42-0331370
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			0.0
Entity Common Stock, Shares Outstanding		13,370,788
Auditor Name	DELOITTE & TOUCHE LLP
Auditor Location	Milwaukee, Wisconsin
Auditor Firm ID	34
WPL [Member]
Entity Information [Line Items]
Entity Registrant Name	WISCONSIN POWER & LIGHT CO
Entity Central Index Key	0000107832
Entity Incorporation, State or Country Code	WI
Entity Address, Address Line One	4902 N. Biltmore Lane
Entity Address, City or Town	Madison
Entity Address, State or Province	WI
Entity Address, Postal Zip Code	53718
City Area Code	608
Local Phone Number	458-3311
Entity File Number	0-337
Entity Tax Identification Number	39-0714890
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 0.0
Entity Common Stock, Shares Outstanding		13,236,601
Auditor Name	DELOITTE & TOUCHE LLP
Auditor Location	Milwaukee, Wisconsin
Auditor Firm ID	34

XML

Consolidated Statements Of Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues:
Electric utility	$ 3,081	$ 2,920	$ 3,064
Gas utility	456	373	455
Other utility	49	49	46
Non-utility	83	74	83
Total revenues	3,669	3,416	3,648
Operating expenses:
Electric production fuel and purchased power	642	652	777
Electric transmission service	537	449	481
Cost of gas sold	258	182	222
Other operation and maintenance	676	670	712
Depreciation and amortization	657	615	567
Taxes other than income taxes	104	108	111
Total operating expenses	2,874	2,676	2,870
Operating income (loss)	795	740	778
Other (income) and deductions:
Interest expense	277	275	273
Equity income from unconsolidated investments, net	(62)	(61)	(53)
Allowance for funds used during construction	(25)	(55)	(93)
Other	5	14	15
Total other (income) and deductions	195	173	142
Income before income taxes	600	567	636
Income tax expense (benefit)	(74)	(57)	69
Net income	674	624	567
Preferred dividend requirements of Interstate Power and Light Company	15	10	10
Net income attributable to common shareowners	$ 659	$ 614	$ 557
Weighted average number of common shares outstanding:
Basic (in shares)	250.2	248.4	238.5
Diluted (in shares)	250.7	248.7	239.0
Earnings per weighted average common share attributable to Alliant Energy common shareowners:
Basic (in dollars per share)	$ 2.63	$ 2.47	$ 2.34
Diluted (in dollars per share)	$ 2.63	$ 2.47	$ 2.33
IPL [Member]
Revenues:
Electric utility	$ 1,752	$ 1,695	$ 1,781
Gas utility	265	208	264
Other utility	46	44	44
Total revenues	2,063	1,947	2,089
Operating expenses:
Electric production fuel and purchased power	295	352	435
Electric transmission service	367	298	340
Cost of gas sold	149	99	120
Other operation and maintenance	362	375	404
Depreciation and amortization	375	356	327
Taxes other than income taxes	55	57	60
Total operating expenses	1,603	1,537	1,686
Operating income (loss)	460	410	403
Other (income) and deductions:
Interest expense	139	139	127
Allowance for funds used during construction	(9)	(24)	(50)
Other	1	8	8
Total other (income) and deductions	131	123	85
Income before income taxes	329	287	318
Income tax expense (benefit)	(36)	(47)	24
Net income	365	334	294
Preferred dividend requirements of Interstate Power and Light Company	15	10	10
Net income attributable to common shareowners	350	324	284
WPL [Member]
Revenues:
Electric utility	1,329	1,225	1,283
Gas utility	191	165	191
Other utility	3	5	2
Total revenues	1,523	1,395	1,476
Operating expenses:
Electric production fuel and purchased power	347	300	342
Electric transmission service	170	151	141
Cost of gas sold	109	83	102
Other operation and maintenance	268	254	261
Depreciation and amortization	276	254	236
Taxes other than income taxes	45	47	47
Total operating expenses	1,215	1,089	1,129
Operating income (loss)	308	306	347
Other (income) and deductions:
Interest expense	105	104	102
Allowance for funds used during construction	(16)	(31)	(43)
Other	2	3	6
Total other (income) and deductions	91	76	65
Income before income taxes	217	230	282
Income tax expense (benefit)	(51)	(19)	49
Net income	$ 268	$ 249	$ 233

XML

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 39	$ 54
Accounts receivable, less allowance for expected credit losses	440	412
Production fuel, at weighted average cost	51	66
Gas stored underground, at weighted average cost	82	46
Materials and supplies, at weighted average cost	113	105
Regulatory assets	104	81
Other	240	123
Total current assets	1,069	887
Property, plant and equipment, net	14,987	14,336
Investments:
ATC Holdings	338	331
Other	179	154
Total investments	517	485
Other assets:
Regulatory assets	1,836	1,929
Deferred charges and other	144	73
Total other assets	1,980	2,002
Total assets	18,553	17,710
Current liabilities:
Current maturities of long-term debt	633	8
Commercial paper	515	389
Accounts payable	436	377
Accrued taxes	58	67
Regulatory liabilities	186	249
Other	226	207
Total current liabilities	2,054	1,297
Long-term debt, net (excluding current portion)	6,735	6,769
Other liabilities:
Deferred tax liabilities	1,927	1,814
Regulatory liabilities	1,085	1,057
Pension and other benefit obligations	374	511
Other	388	374
Total other liabilities	3,774	3,756
Commitments and contingencies (Note 17)
Common equity:
Common stock	3	2
Additional paid-in capital	2,749	2,704
Retained earnings	3,250	2,994
Accumulated other comprehensive loss	0	(1)
Shares in deferred compensation trust - 383,532 and 380,542 shares at a weighted average cost of $30.59 and $28.73 per share	(12)	(11)
Total common equity	5,990	5,688
Cumulative preferred stock of Interstate Power and Light Company	0	200
Total equity	5,990	5,888
Total liabilities and equity	18,553	17,710
IPL [Member]
Current assets:
Cash and cash equivalents	34	50
Accounts receivable, less allowance for expected credit losses	241	210
Income taxes refunds receivable	8	26
Production fuel, at weighted average cost	29	48
Gas stored underground, at weighted average cost	40	20
Materials and supplies, at weighted average cost	70	63
Regulatory assets	73	52
Other	69	27
Total current assets	564	496
Property, plant and equipment, net	7,983	7,889
Other assets:
Regulatory assets	1,370	1,431
Deferred charges and other	79	33
Total other assets	1,449	1,464
Total assets	9,996	9,849
Current liabilities:
Current maturities of long-term debt	0	0
Commercial paper	0	0
Accounts payable	173	162
Accounts payable to associated companies	39	45
Accrued taxes	56	54
Regulatory liabilities	84	103
Accrued interest	36	34
Other	67	49
Total current liabilities	455	447
Long-term debt, net (excluding current portion)	3,643	3,345
Other liabilities:
Deferred tax liabilities	1,083	1,035
Regulatory liabilities	607	573
Pension and other benefit obligations	127	186
Other	312	299
Total other liabilities	2,129	2,093
Commitments and contingencies (Note 17)
Common equity:
Common stock	33	33
Additional paid-in capital	2,807	2,752
Retained earnings	929	979
Total common equity	3,769	3,764
Cumulative preferred stock of Interstate Power and Light Company	0	200
Total equity	3,769	3,964
Total liabilities and equity	9,996	9,849
WPL [Member]
Current assets:
Cash and cash equivalents	2	3
Accounts receivable, less allowance for expected credit losses	188	192
Production fuel, at weighted average cost	23	18
Gas stored underground, at weighted average cost	42	26
Materials and supplies, at weighted average cost	41	40
Regulatory assets	31	29
Prepaid gross receipts tax	40	42
Other	86	12
Total current assets	453	362
Property, plant and equipment, net	6,538	6,022
Other assets:
Regulatory assets	466	498
Deferred charges and other	61	30
Total other assets	527	528
Total assets	7,518	6,912
Current liabilities:
Current maturities of long-term debt	250	0
Commercial paper	236	257
Accounts payable	190	154
Accounts payable to associated companies	39	35
Regulatory liabilities	102	146
Other	73	82
Total current liabilities	890	674
Long-term debt, net (excluding current portion)	2,179	2,130
Other liabilities:
Deferred tax liabilities	753	702
Regulatory liabilities	478	484
Pension and other benefit obligations	159	222
Other	236	222
Total other liabilities	1,626	1,630
Commitments and contingencies (Note 17)
Common equity:
Common stock	66	66
Additional paid-in capital	1,704	1,459
Retained earnings	1,053	953
Total common equity	2,823	2,478
Total equity	2,823	2,478
Total liabilities and equity	$ 7,518	$ 6,912

XML

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	480,000,000	480,000,000
Common stock, shares outstanding (in shares)	250,474,529	249,868,415
Shares in deferred compensation trust (in shares)	383,532	380,542
Shares in deferred compensation trust, weighted average cost per share (in dollars per share)	$ 30.59	$ 28.73
IPL [Member]
Common stock, par value (in dollars per share)	$ 2.50	$ 2.50
Common stock, shares authorized (in shares)	24,000,000	24,000,000
Common stock, shares outstanding (in shares)	13,370,788	13,370,788
WPL [Member]
Common stock, par value (in dollars per share)	$ 5	$ 5
Common stock, shares authorized (in shares)	18,000,000	18,000,000
Common stock, shares outstanding (in shares)	13,236,601	13,236,601

XML

Consolidated Statements Of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from (used for) operating activities:
Net income	$ 674	$ 624	$ 567
Adjustments to reconcile net income to net cash flows from (used for) operating activities:
Depreciation and amortization	657	615	567
Deferred tax expense (benefit) and tax credits	(78)	(66)	56
Equity component of allowance for funds used during construction	(18)	(39)	(66)
Other	35	37	20
Other changes in assets and liabilities:
Accounts receivable	(530)	(468)	(472)
Derivative assets	(142)	(7)	2
Regulatory assets	51	(130)	(16)
Regulatory liabilities	(66)	(113)	(40)
Deferred income taxes	193	171	54
Pension and other benefit obligations	(137)	27	(25)
DAEC PPA amendment buyout payment	0	(110)	0
Other	(57)	(40)	13
Net cash flows from (used for) operating activities	582	501	660
Cash flows from (used for) investing activities:
Utility construction and acquisition expenditures	(1,070)	(1,293)	(1,539)
Other construction and acquisition expenditures	(99)	(73)	(101)
Cash receipts on sold receivables	502	458	413
Other	(61)	(43)	(60)
Net cash flows from (used for) investing activities	(728)	(951)	(1,287)
Cash flows from financing activities:
Common stock dividends	(403)	(377)	(337)
Proceeds from issuance of common stock, net	28	247	390
Payments to redeem cumulative preferred stock of IPL	(200)	0	0
Proceeds from issuance of long-term debt	600	1,250	950
Payments to retire long-term debt	(8)	(657)	(256)
Net change in commercial paper	126	52	(104)
Other	(13)	(27)	(24)
Net cash flows from (used for) financing activities	130	488	619
Net increase (decrease) in cash, cash equivalents and restricted cash	(16)	38	(8)
Cash, cash equivalents and restricted cash at beginning of period	56	18	26
Cash, cash equivalents and restricted cash at end of period	40	56	18
Supplemental cash flows information:
Interest	(272)	(274)	(268)
Income taxes, net	(3)	5	21
Significant non-cash investing and financing activities:
Accrued capital expenditures	141	131	196
Beneficial interest obtained in exchange for securitized accounts receivable	214	188	188
IPL [Member]
Cash flows from (used for) operating activities:
Net income	365	334	294
Adjustments to reconcile net income to net cash flows from (used for) operating activities:
Depreciation and amortization	375	356	327
Deferred tax expense (benefit) and tax credits	(14)	(52)	15
Equity component of allowance for funds used during construction	(7)	(17)	(35)
Other	11	12	1
Other changes in assets and liabilities:
Accounts receivable	(539)	(466)	(467)
Derivative assets	(55)	(7)	(5)
Regulatory assets	30	(93)	(11)
Accounts payable	15	6	(21)
Regulatory liabilities	1	(20)	2
Deferred income taxes	62	79	35
Pension and other benefit obligations	(59)	18	(11)
DAEC PPA amendment buyout payment	0	(110)	0
Other	(32)	(46)	49
Net cash flows from (used for) operating activities	153	(6)	173
Cash flows from (used for) investing activities:
Utility construction and acquisition expenditures	(384)	(687)	(1,020)
Cash receipts on sold receivables	502	458	413
Other	(27)	(72)	(60)
Net cash flows from (used for) investing activities	91	(301)	(667)
Cash flows from financing activities:
Common stock dividends	(400)	(236)	(168)
Capital contributions from parent	50	404	125
Payments to redeem cumulative preferred stock of IPL	(200)	0	0
Proceeds from issuance of long-term debt	300	400	600
Payments to retire long-term debt	0	(200)	0
Net change in commercial paper	0	0	(50)
Other	(10)	(20)	(16)
Net cash flows from (used for) financing activities	(260)	348	491
Net increase (decrease) in cash, cash equivalents and restricted cash	(16)	41	(3)
Cash, cash equivalents and restricted cash at beginning of period	50	9	12
Cash, cash equivalents and restricted cash at end of period	34	50	9
Supplemental cash flows information:
Interest	(138)	(141)	(122)
Income taxes, net	47	(18)	7
Significant non-cash investing and financing activities:
Accrued capital expenditures	57	73	112
Beneficial interest obtained in exchange for securitized accounts receivable	214	188	188
WPL [Member]
Cash flows from (used for) operating activities:
Net income	268	249	233
Adjustments to reconcile net income to net cash flows from (used for) operating activities:
Depreciation and amortization	276	254	236
Deferred tax expense (benefit) and tax credits	(79)	(15)	24
Other	11	2	(12)
Other changes in assets and liabilities:
Derivative assets	(87)	0	6
Regulatory liabilities	(67)	(93)	(42)
Deferred income taxes	132	90	20
Pension and other benefit obligations	(63)	11	(7)
Other	(20)	(32)	(35)
Net cash flows from (used for) operating activities	371	466	423
Cash flows from (used for) investing activities:
Utility construction and acquisition expenditures	(686)	(606)	(519)
Other	(30)	(7)	(38)
Net cash flows from (used for) investing activities	(716)	(613)	(557)
Cash flows from financing activities:
Common stock dividends	(168)	(160)	(144)
Capital contributions from parent	245	25	125
Proceeds from issuance of long-term debt	300	350	350
Payments to retire long-term debt	0	(150)	(250)
Net change in commercial paper	(21)	89	63
Other	(12)	(8)	(15)
Net cash flows from (used for) financing activities	344	146	129
Net increase (decrease) in cash, cash equivalents and restricted cash	(1)	(1)	(5)
Cash, cash equivalents and restricted cash at beginning of period	3	4	9
Cash, cash equivalents and restricted cash at end of period	2	3	4
Supplemental cash flows information:
Interest	(101)	(102)	(103)
Income taxes, net	(38)	13	(29)
Significant non-cash investing and financing activities:
Accrued capital expenditures	$ 81	$ 55	$ 82

XML

Consolidated Statements of Common Equity - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment [Member]	IPL [Member]	WPL [Member]	Common Stock [Member]	Common Stock [Member] IPL [Member]	Common Stock [Member] WPL [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] IPL [Member]	Additional Paid-in Capital [Member] WPL [Member]	Retained Earnings [Member]	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Retained Earnings [Member] IPL [Member]	Retained Earnings [Member] WPL [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Shares in Deferred Compensation Trust [Member]	Cumulative Preferred Stock [Member]	Cumulative Preferred Stock [Member] IPL [Member]
Beginning balance at Dec. 31, 2018					$ 2	$ 33	$ 66	$ 2,046	$ 2,223	$ 1,309	$ 2,546		$ 775	$ 775	$ 2	$ (10)	$ 200	$ 200
Beginning balance at Dec. 31, 2018	$ 4,786		$ 3,231	$ 2,150
Increase (Decrease) in Shareowners' Equity [Roll Forward]
Net income attributable to common shareowners	557		284								557		284
Net income	567		294	233										233
Common stock dividends	(337)		(168)	(144)							(337)		(168)	(144)
Equity forward settlements and Shareowner Direct Plan issuances	390							390
Capital contributions from parent			125	125					125	125
Equity-based compensation plans and other	10							10
Payments to redeem cumulative preferred stock of IPL	0		0
Other comprehensive income (loss), net of tax	(1)														(1)
Ending balance at Dec. 31, 2019					2	33	66	2,446	2,348	1,434	2,766		891	864	1	(10)	200	200
Ending balance at Dec. 31, 2019	5,405		3,472	2,364
Increase (Decrease) in Shareowners' Equity [Roll Forward]
Adoption of new accounting standard, net of tax		$ (9)										$ (9)
Net income attributable to common shareowners	614		324								614		324
Net income	624		334	249										249
Common stock dividends	(377)		(236)	(160)							(377)		(236)	(160)
Equity forward settlements and Shareowner Direct Plan issuances	247							247
Capital contributions from parent			404	25					404	25
Equity-based compensation plans and other	10							11								(1)
Payments to redeem cumulative preferred stock of IPL	0		0
Other comprehensive income (loss), net of tax	(2)														(2)
Ending balance at Dec. 31, 2020	5,688		3,764	2,478	2	33	66	2,704	2,752	1,459	2,994		979	953	(1)	(11)	200	200
Ending balance at Dec. 31, 2020	5,888		3,964	2,478
Increase (Decrease) in Shareowners' Equity [Roll Forward]
Adoption of new accounting standard, net of tax	2,994		979	953
Net income attributable to common shareowners	659		350								659		350
Net income	674		365	268										268
Common stock dividends	(403)		(400)	(168)							(403)		(400)	(168)
Equity forward settlements and Shareowner Direct Plan issuances	28				1			27
Capital contributions from parent			50	245					50	245
Equity-based compensation plans and other	17		5					18	5							(1)
Payments to redeem cumulative preferred stock of IPL	(200)		(200)														(200)	(200)
Other comprehensive income (loss), net of tax	1														1
Ending balance at Dec. 31, 2021	5,990		3,769	2,823	$ 3	$ 33	$ 66	$ 2,749	$ 2,807	$ 1,704	$ 3,250		$ 929	$ 1,053	$ 0	$ (12)	$ 0	$ 0
Ending balance at Dec. 31, 2021	5,990		3,769	2,823
Increase (Decrease) in Shareowners' Equity [Roll Forward]
Adoption of new accounting standard, net of tax	$ 3,250		$ 929	$ 1,053

XML

Consolidated Statements of Common Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Stockholders' Equity [Abstract]
Common stock dividends (in dollars per share)	$ 1.61	$ 1.52	$ 1.42

XML

Summary Of Significant Accounting Policies

12 Months Ended

Dec. 31, 2021

Summary Of Significant Accounting Policies

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES(a) General -

Description of Business - Alliant Energy’s financial statements include the accounts of Alliant Energy and its consolidated subsidiaries. Alliant Energy is a Midwest U.S. energy holding company, whose primary wholly-owned subsidiaries are IPL, WPL, AEF and Corporate Services.

IPL’s financial statements include the accounts of IPL and its consolidated subsidiaries, including IPL SPE LLC, which is used for IPL’s sales of accounts receivable program. IPL is a direct subsidiary of Alliant Energy and is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Iowa. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa, and is engaged in the generation and distribution of steam for two customers in Cedar Rapids, Iowa.

WPL’s financial statements include the accounts of WPL and its consolidated subsidiary. WPL is a direct subsidiary of Alliant Energy and is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Wisconsin. WPL also sells electricity to wholesale customers in Wisconsin.

AEF is comprised of Travero, ATI, corporate venture investments, a non-utility wind farm, the Sheboygan Falls Energy Facility and other non-utility holdings. Travero includes a short-line rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; freight brokerage services; and a rail-served warehouse in Iowa, which began operations in 2021. ATI, a wholly-owned subsidiary of AEF, holds all of Alliant Energy’s interest in ATC Holdings. Corporate venture investments includes various minority ownership interests in regional and national venture funds, including a coalition with different energy companies across the U.S., working together to help identify and research innovative products, technologies and business models within the emerging energy economy. The non-utility wind farm includes a 50% cash equity ownership interest in a 225 MW wind farm located in Oklahoma. The Sheboygan Falls Energy Facility is a 347 MW, simple-cycle, natural gas-fired EGU near Sheboygan Falls, Wisconsin, which is leased to WPL for an initial period of 20 years ending in 2025.

Corporate Services is the subsidiary formed to provide administrative services to Alliant Energy and its subsidiaries.

In March 2020, COVID-19 was declared a global pandemic, which has resulted in widespread travel restrictions, closures of commercial spaces and industrial facilities, and more people working from home in Alliant Energy’s service territories. For 2020 and 2021, Alliant Energy, IPL and WPL considered the impact of COVID-19 on their overall business operations, financial condition, results of operations and cash flows, along with assumptions and estimates used. In 2020, Alliant Energy, IPL and WPL experienced higher electric residential sales and lower electric commercial and industrial sales as a result of the pandemic. In 2021, changes in COVID-19 impacts resulted in lower electric residential sales and higher electric commercial and industrial sales. The degree to which the COVID-19 pandemic may impact Alliant Energy, IPL and WPL in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities.

Basis of Presentation - The financial statements reflect investments in controlled subsidiaries on a consolidated basis and Alliant Energy’s, IPL’s and WPL’s proportionate shares of jointly-owned utility EGUs. Unconsolidated investments that Alliant Energy and WPL do not control are accounted for under the equity method of accounting. Under the equity method of accounting, Alliant Energy and WPL initially record the investment at cost, and adjust the carrying amount of the investment to recognize their respective share of the earnings or losses of the investee. Dividends received from an investee reduce the carrying amount of the equity investment. Investments that do not meet the criteria for consolidation or the equity method of accounting are accounted for under the cost method.

All intercompany balances and transactions, other than certain transactions affecting the rate-making process at IPL and WPL, have been eliminated from the financial statements. Such transactions not eliminated include costs that are recoverable from customers through rate-making processes. The financial statements are prepared in conformity with GAAP, which give recognition to the rate-making practices of FERC and state commissions having regulatory jurisdiction.

Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.

Use of Estimates - The preparation of the financial statements requires management to make estimates and assumptions that affect: (a) the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements; and (b) the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

(b) Regulatory Assets and Regulatory Liabilities - Alliant Energy, IPL and WPL are subject to regulation by FERC and various state regulatory commissions. As a result, Alliant Energy, IPL and WPL are subject to GAAP provisions for regulated operations, which provide that rate-regulated public utilities record certain costs and credits allowed in the rate-making process in different periods than for non-utility entities. Regulatory assets generally represent incurred costs that have been deferred as such costs are probable of recovery in future customer rates. Regulatory liabilities generally represent obligations to make refunds to customers or amounts collected in rates for which the related costs have not yet been incurred. Amounts recorded as regulatory assets or regulatory liabilities are generally recognized in the income statements at the time they are reflected in rates.(c) Income Taxes - The liability method of accounting is followed for deferred taxes, which requires the establishment of deferred tax assets and liabilities, as appropriate, for temporary differences between the tax basis of assets and liabilities and the amounts reported in the financial statements. Deferred taxes are recorded using currently enacted tax rates and estimates of state apportionment. Changes in deferred tax assets and liabilities associated with certain property-related differences at IPL are accounted for differently than other subsidiaries of Alliant Energy due to rate-making practices in Iowa. Rate-making practices in Iowa do not allow the impact of certain deferred tax expenses (benefits) to be included in the determination of retail rates. Based on these rate-making practices, deferred tax expense (benefit) related to these property-related differences at IPL is not recorded in the income statement but instead recorded to regulatory assets or regulatory liabilities until these temporary differences reverse. In Wisconsin, the PSCW allows rate recovery of deferred tax expense on all temporary differences.

Investment tax credits are deferred and amortized to income over the average lives of the related property. Federal Tax Reform repealed corporate federal alternative minimum tax and allowed unutilized alternative minimum tax credits to be refunded over four tax years beginning with the U.S. federal tax return for calendar year 2018. Pursuant to the Coronavirus Aid, Relief, and Economic Security Act, Alliant Energy received the remaining alternative minimum tax credits refunds in 2020. Other tax credits reduce income tax expense in the year claimed.

Alliant Energy files a consolidated federal income tax return and a combined return in Wisconsin, which include Alliant Energy and its subsidiaries. Alliant Energy subsidiaries with a presence in Iowa file as part of a consolidated return in Iowa.

Alliant Energy allocates consolidated income tax expense to its subsidiaries that are members of the group that file a consolidated or combined income tax return. IPL and WPL use the modified separate return approach for calculating their income tax provisions and related deferred tax assets and liabilities. IPL and WPL are assumed to file separate tax returns with the federal and state taxing authorities, except that net operating losses (and other current or deferred tax attributes) are characterized as realized (or realizable) by IPL and WPL when those tax attributes are realized (or realizable) by the consolidated tax return group of Alliant Energy (even if IPL and WPL would not otherwise have realized the attributes on a stand-alone basis). The difference in the income taxes recorded for IPL and WPL under the modified separate return method compared to the income taxes recorded on a separate return basis was not material in 2021, 2020 and 2019.

(d) Cash, Cash Equivalents and Restricted Cash - Cash and cash equivalents include short-term liquid investments that have original maturities of less than 90 days. At December 31, 2021, Alliant Energy’s and IPL’s cash and cash equivalents included $32 million of money market fund investments, with an interest rate of 0.04%. At December 31, 2021 and 2020, Alliant Energy’s restricted cash related to requirements in Sheboygan Power, LLC’s debt agreement.(e) Property, Plant and Equipment -

Utility Plant -

General - Utility plant is recorded at the original cost of acquisition or construction, which includes material, labor, contractor services, AFUDC and allocable overheads, such as supervision, engineering, benefits, certain taxes and transportation. Repairs, replacements and renewals of items of property determined to be less than a unit of property or that do not increase the property’s life or functionality are charged to maintenance expense. Property, plant and equipment that is probable of being retired early is classified as plant anticipated to be retired early. Generally, ordinary retirements of utility plant and salvage value are netted and charged to accumulated depreciation upon removal from utility plant accounts and no gain or loss is recognized consistent with rate-making principles. However, if regulators have approved recovery of the remaining net book value of property, plant and equipment that is retired early, or such approval by regulators is probable, the remaining net book value is reclassified from property, plant and equipment to regulatory assets upon retirement.

Depreciation - IPL and WPL use a combination of remaining life and straight-line depreciation methods as approved by their respective regulatory commissions. The composite or group method of depreciation is used, in which a single depreciation rate is applied to the gross investment in a particular class of property. This method pools similar assets and then depreciates each group as a whole. Periodic depreciation studies are performed to determine the appropriate group lives, net salvage, estimated cost of removal and group depreciation rates. These depreciation studies are subject to review and approval by IPL’s and WPL’s respective regulatory commissions. Depreciation expense is included within the recoverable cost of service component of rates collected from customers. The average rates of depreciation for electric, gas and other properties, consistent with current rate-making practices, were as follows:

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Electric - generation	3.4%	3.5%	3.8%	3.5%	3.5%	3.6%
Electric - distribution	2.9%	2.8%	2.9%	2.6%	2.6%	2.6%
Electric - other	5.7%	5.2%	5.3%	7.4%	6.1%	5.8%
Gas	3.3%	3.3%	3.3%	2.4%	2.4%	2.5%
Other	6.1%	6.3%	5.9%	5.4%	5.9%	5.6%

AFUDC - AFUDC represents costs to finance construction additions, including a return on equity component and cost of debt component as required by regulatory accounting. AFUDC for IPL’s construction projects is calculated in accordance with FERC guidelines. AFUDC for WPL’s retail and wholesale jurisdiction construction projects is calculated in accordance with PSCW and FERC guidelines, respectively. The AFUDC rates, computed in accordance with the prescribed regulatory formula, were as follows:

	2021	2020	2019
IPL (Wind generation CWIP)	7.0%	7.1%	7.4%
IPL (other CWIP)	7.2%	7.2%	7.5%
WPL (retail jurisdiction)	7.0%	7.0%	6.8%
WPL (wholesale jurisdiction)	5.6%	6.3%	6.9%

In accordance with their respective regulatory commission decisions, IPL applies its AFUDC rates to 100% of applicable CWIP balances and WPL generally applies its AFUDC rates to 50% of applicable CWIP balances. WPL may apply its AFUDC rates to 100% of the retail portion of the CWIP balances for construction projects requiring a CA or CPCN that were approved by the PSCW after its then most recent rate order, including West Riverside and the first and second solar generation CAs.

Non-utility and Other Property -

General - Non-utility property is recorded at the original cost of acquisition or construction, which includes material, labor and contractor services. Repairs, replacements and renewals of items of property determined to be less than a unit of property or that do not increase the property’s life or functionality are charged to maintenance expense. Upon retirement or sale of non-utility property, the original cost and related accumulated depreciation are removed from the accounts and any gain or loss is included in the income statements.

Costs related to software developed or obtained for internal use are capitalized and amortized on a straight-line basis over the estimated useful life of the related software. If software is retired prior to being fully amortized, the remaining book value is recorded as a loss in the income statements.

(f) Revenue Recognition -

Utility - Revenues from Alliant Energy’s utility business are primarily from electric and gas sales to customers. Utility revenues are recognized over time as services are rendered or commodities are delivered to customers, and include billed and unbilled components. The billed component is based on the reading of customers’ meters, which occurs on a systematic basis throughout each reporting period and represents the fair value of the services provided or commodities delivered. The unbilled component is estimated and recorded at the end of each reporting period based on estimated amounts of energy delivered to customers since the end of each customer’s last billing period. The unbilled component is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates.

IPL and WPL accrue revenues from their wholesale customers to the extent that the actual net revenue requirements calculated in accordance with FERC-approved formula rates for the reporting period are higher or lower than the amounts billed to wholesale customers during such period. Regulatory assets or regulatory liabilities are recorded as the offset for these accrued revenues under formulaic rate-making programs. As of December 31, 2021, the related amounts accrued for IPL and WPL were not material.

IPL and WPL participate in bid/offer-based wholesale energy and ancillary services markets operated by MISO. The MISO transactions are grouped together, resulting in a net supply to or net purchase from MISO for each hour of each day. The net supply to MISO is recorded as bulk power sales in “Electric utility revenues” and the net purchase from MISO is recorded in “Electric production fuel and purchased power” in the income statements.

Non-utility - Revenues from Alliant Energy’s non-utility businesses are primarily from its Travero business and are recognized over time as services are rendered to customers.

Taxes Collected from Customers - Sales or various other taxes collected by certain of Alliant Energy’s subsidiaries on behalf of other agencies are recorded on a net basis and are not included in revenues.

Other - Alliant Energy, IPL and WPL do not disclose the value of unsatisfied performance obligations for: (i) contracts with an original expected length of one year or less; and (ii) contracts for which revenue is recognized at the amount to which they have the right to invoice for services performed.(g) Utility Cost Recovery Mechanisms

Electric Production Fuel and Purchased Power (Fuel-related Costs) - Fuel-related costs are incurred to generate and purchase electricity to meet the demand of IPL’s and WPL’s electric customers. These fuel-related costs include the cost of fossil fuels (primarily natural gas and coal) used to produce electricity at their EGUs, and electricity purchased from MISO wholesale energy markets and under PPAs. These fuel-related costs are recorded in “Electric production fuel and purchased power” in the income statements.

IPL Retail - The cost recovery mechanisms for IPL’s retail electric customers provide for monthly adjustments to their electric rates for changes in fuel-related costs. Changes in the under-/over-collection of these costs are recognized in “Electric production fuel and purchased power” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

WPL Retail - The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. If WPL’s actual fuel-related costs fall outside these fuel monitoring ranges, WPL is authorized to defer the incremental under-/over-collection of fuel-related costs that are outside the approved ranges. Deferral of under-collections are reduced to the extent actual return on common equity earned by WPL during the fuel cost plan year exceeds the most recently authorized return on common equity. Deferred amounts for fuel-related costs outside the approved fuel monitoring ranges are recognized in “Electric production fuel and purchased power” in Alliant Energy’s and WPL’s income statements. The cumulative effects of these deferred amounts are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and WPL’s balance sheets until they are reflected in future billings to customers.

IPL and WPL Wholesale - The cost recovery mechanisms for IPL’s and WPL’s wholesale electric customers provide for subsequent adjustments to their electric rates for changes in fuel-related costs. Changes in the under-/over-collection of these costs are recognized in “Electric production fuel and purchased power” in the income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Purchased Electric Capacity - PPAs help meet the electricity demand of IPL’s and WPL’s customers. Certain PPAs include minimum payments for IPL’s and WPL’s rights to electric generating capacity, which are charged each period to “Electric production fuel and purchased power” in the income statements. Purchased electric capacity expenses are recovered from IPL’s and WPL’s retail electric customers through changes in base rates determined during periodic rate proceedings. Purchased electric capacity expenses are recovered from IPL’s and WPL’s wholesale electric customers through annual changes in base rates determined by a formula rate structure.

Electric Transmission Service - Costs incurred for the transmission of electricity to meet the demands of IPL’s and WPL’s customers are charged to “Electric transmission service” in the income statements.

IPL Retail - Electric transmission service expense is recovered from IPL’s retail electric customers through a transmission cost rider. This cost recovery mechanism provides for periodic adjustments to electric rates charged to retail electric customers for changes in electric transmission service expense. Changes in the under-/over-collection of these costs are recognized in “Electric transmission service” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

WPL Retail - Electric transmission service expense is recovered from WPL’s retail electric customers through changes in base rates determined during periodic rate proceedings. Pursuant to escrow accounting treatment approved by the PSCW, the difference between actual electric transmission service expense incurred and the amount of electric transmission service costs collected from customers as electric revenues is recognized in “Electric transmission service” in Alliant Energy’s and WPL’s income statements. An offsetting amount is recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and WPL’s balance sheets until reflected in future billings to customers.

IPL and WPL Wholesale - IPL and WPL arrange transmission service for the majority of their respective wholesale electric customers. Electric transmission service expense is allocated to and recovered from these customers based on a load ratio share computation.

Cost of Gas Sold - Costs are incurred for the purchase, transportation and storage of natural gas to serve IPL’s and WPL’s gas customers and the costs associated with the natural gas delivered to customers are charged to “Cost of gas sold” in the income statements. The tariffs for IPL’s and WPL’s retail gas customers provide for subsequent adjustments to their rates periodically for changes in the cost of gas sold. Changes in the under-/over-collection of these costs are also recognized in “Cost of gas sold” in the income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Energy Efficiency Costs - Costs incurred to fund energy efficiency programs and initiatives that help customers reduce their energy usage are charged to “Other operation and maintenance” in the income statements. Energy efficiency costs incurred by IPL are recovered from its retail electric and gas customers through energy efficiency and demand response cost recovery factor tariffs, which are revised annually and include a reconciliation to eliminate any under-/over-collection of energy efficiency costs from prior periods. Energy efficiency costs incurred by WPL are recovered from retail electric and gas customers through changes in base rates determined during periodic rate proceedings. Reconciliations of any under-/over-collection of energy efficiency costs from prior periods are also addressed in WPL’s periodic rate proceedings. Changes in the under-/over-collection of energy efficiency costs for IPL and WPL are recognized in “Other operation and maintenance” in the income statements. The cumulative effects of the under-/over-collection of these costs for IPL and WPL are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Renewable Energy Rider - Effective with the implementation of final rates covering the 2020 forward-looking Test Period, IPL recovers a return of, as well as earn a return on, its new wind generation placed in service in 2019 and 2020 from its retail electric customers through a renewable energy rider. Other applicable costs and tax benefits associated with the new wind generation, excluding operation and maintenance expenses, are also included in the rider. This cost recovery mechanism provides for annual adjustments to electric rates charged to IPL’s retail electric customers for actual renewable energy costs and tax benefits. Changes in the under-/over-collection of these costs are recognized in “Electric utility revenue” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs for IPL are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

(h) Financial Instruments - Financial instruments are periodically used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. The fair value of those financial instruments that are determined to be derivatives are recorded as assets or liabilities on the balance sheets. Certain commodity purchase and sales contracts qualified for and were designated under the normal purchase and sale exception, and were accounted for on the accrual basis of accounting. Alliant Energy, IPL and WPL have elected to not net the fair value amounts of derivatives subject to a master netting arrangement by counterparty. Alliant Energy, IPL and WPL do not offset fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) against fair value amounts recognized for derivative instruments that are executed with the same counterparty under the same master netting arrangement. Refer to Note 2 for discussion of the recognition of regulatory assets and regulatory liabilities related to the unrealized losses and gains on derivative instruments. Refer to Notes 15, 16 and 17(f) for further discussion of derivatives and related credit risk.(i) Asset Impairments -

Property, Plant and Equipment of Regulated Operations - Property, plant and equipment of regulated operations are reviewed for possible impairment whenever events or changes in circumstances indicate all or a portion of the carrying value of the assets may be disallowed for rate-making purposes. If IPL or WPL are disallowed recovery of any portion of, or are only allowed a partial return on, the carrying value of their regulated property, plant and equipment that is under construction, has been recently completed or is probable of abandonment, or conclude it is probable recovery or a full return will be disallowed, then an impairment charge is recognized.

Property, Plant and Equipment of Non-utility Operations - Property, plant and equipment of non-utility operations are reviewed for possible impairment whenever events or changes in circumstances indicate the carrying value of the assets may not be recoverable. Impairment is indicated if the carrying value of an asset exceeds its undiscounted future cash flows. If an impairment is indicated, a charge is recognized equal to the amount the carrying value exceeds the asset’s fair value.

Unconsolidated Equity Investments - If events or circumstances indicate the carrying value of investments accounted for under the equity method of accounting exceeds fair value and the decline in value is other than temporary, potential impairment is assessed. If an impairment is indicated, a charge is recognized equal to the amount the carrying value exceeds the investment’s fair value.

(j) Asset Retirement Obligations - The fair value of a legal obligation associated with the retirement of an asset is recorded as a liability when an asset is placed in service, when a legal obligation is subsequently identified or when sufficient information becomes available to determine a reasonable estimate of the fair value of future retirement costs. When an ARO is recorded as a liability, an equivalent amount is added to the asset cost. The fair value of AROs at inception is determined using discounted cash flows analyses. The liability is accreted to its present value and the capitalized cost is depreciated over the useful life of the related asset. Accretion and depreciation expenses related to AROs for IPL’s and WPL’s regulated operations are recorded to regulatory assets on the balance sheets. Revisions in estimated cash flows for IPL’s and WPL’s regulated operations are recorded as an increase or decrease to the ARO liability, with an offset to the asset cost, unless the asset is already retired and then the offset is recorded to regulatory assets or regulatory liabilities on the balance sheets. Upon regulatory approval to recover IPL’s AROs expenditures, its regulatory assets are amortized to depreciation and amortization expenses in Alliant Energy’s and IPL’s income statements over the same time period the ARO expenditures are recovered from IPL’s customers. WPL’s regulatory assets related to AROs are recovered as a component of depreciation rates pursuant to PSCW and FERC orders. Upon settlement of the ARO liability, an entity settles the obligation for its recorded amount or incurs a gain or loss. Any gains or losses related to AROs for IPL’s and WPL’s regulated operations are recorded to regulatory liabilities or regulatory assets on the balance sheets.(k) Debt Issuance and Retirement Costs - Debt issuance costs and debt premiums or discounts are presented on the balance sheets as a direct adjustment to the carrying amount of the related debt liability, and are deferred and amortized over the expected life of each debt issue, considering maturity dates and, if applicable, redemption rights held by others. Alliant Energy’s non-utility businesses and Corporate Services record to interest expense in the period of retirement any unamortized debt issuance costs and debt premiums or discounts on debt retired early.(l) Current Expected Credit Losses Estimates - Current expected credit losses are estimated for trade and other receivables and credit exposures on guarantees of the performance by third parties. The current expected credit losses for short-term trade receivables are based on estimates of losses resulting from the inability of customers to make required payments. The methodology used to estimate losses is based on historical write-offs, regional economic conditions, significant events that could impact collectability, such as impacts related to COVID-19, significant weather related matters including the derecho windstorm and related regulatory actions, and forecasted changes to the accounts receivable aging portfolio and write-offs. The current expected credit losses related to guarantees of the performance by third parties are estimated using both quantitative and qualitative information, which utilizes potential outcomes in a range of possible estimated amounts.In 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 17(d) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s equity statement for 2020.(m) Variable Interest Entities - An entity is considered a VIE if its equity investors do not have sufficient equity at risk for the entity to finance its activities without additional subordinated financial support from other parties, the entity is structured with disproportionate voting rights and substantially all of the entity’s activities are conducted on behalf of the investor with disproportionately fewer voting rights, or its equity investors lack any of the following characteristics: (1) power, through voting rights or similar rights, to direct the activities of the entity that most significantly impact the entity’s economic performance; (2) the obligation to absorb expected losses of the entity; or (3) the right to receive expected benefits of the entity. The primary beneficiary of a VIE is required to consolidate the VIE. The financial statements do not reflect any consolidation of VIEs.(n) Leases - The determination of whether an arrangement qualifies as a lease occurs at the inception of the arrangement. Arrangements that qualify as leases are classified as either operating or finance. Operating and finance lease liabilities represent obligations to make payments arising from the lease. Operating and finance lease assets represent the right to use an underlying asset for the lease term and are recognized at the lease commencement date based on the present value of the lease payments over the lease term. Leases with initial terms less than 12 months are not recognized as leases. For operating leases, an incremental borrowing rate, as determined at the lease commencement date, is used to determine the present value of the lease payments. For finance leases, the rate implicit in the lease, if known, is used to determine the present value of the lease payments. If the rate implicit in the lease is not known, the incremental borrowing rate is used to determine the present value of the lease payments. Lease terms include options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Operating lease expense is recognized on a straight-line basis over the expected lease term. Finance lease expense is comprised of depreciation and amortization, and interest expenses. Finance lease assets related to leased land for solar generation are amortized on a straight-line basis over the lease term, and are accounted for as operating leases for rate-making purposes. All other finance lease assets are depreciated on a straight-line basis over the shorter of the useful life of the underlying asset or the lease term.

IPL [Member]

Summary Of Significant Accounting Policies

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES(a) General -

Description of Business - Alliant Energy’s financial statements include the accounts of Alliant Energy and its consolidated subsidiaries. Alliant Energy is a Midwest U.S. energy holding company, whose primary wholly-owned subsidiaries are IPL, WPL, AEF and Corporate Services.

IPL’s financial statements include the accounts of IPL and its consolidated subsidiaries, including IPL SPE LLC, which is used for IPL’s sales of accounts receivable program. IPL is a direct subsidiary of Alliant Energy and is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Iowa. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa, and is engaged in the generation and distribution of steam for two customers in Cedar Rapids, Iowa.

WPL’s financial statements include the accounts of WPL and its consolidated subsidiary. WPL is a direct subsidiary of Alliant Energy and is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Wisconsin. WPL also sells electricity to wholesale customers in Wisconsin.

AEF is comprised of Travero, ATI, corporate venture investments, a non-utility wind farm, the Sheboygan Falls Energy Facility and other non-utility holdings. Travero includes a short-line rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; freight brokerage services; and a rail-served warehouse in Iowa, which began operations in 2021. ATI, a wholly-owned subsidiary of AEF, holds all of Alliant Energy’s interest in ATC Holdings. Corporate venture investments includes various minority ownership interests in regional and national venture funds, including a coalition with different energy companies across the U.S., working together to help identify and research innovative products, technologies and business models within the emerging energy economy. The non-utility wind farm includes a 50% cash equity ownership interest in a 225 MW wind farm located in Oklahoma. The Sheboygan Falls Energy Facility is a 347 MW, simple-cycle, natural gas-fired EGU near Sheboygan Falls, Wisconsin, which is leased to WPL for an initial period of 20 years ending in 2025.

Corporate Services is the subsidiary formed to provide administrative services to Alliant Energy and its subsidiaries.

In March 2020, COVID-19 was declared a global pandemic, which has resulted in widespread travel restrictions, closures of commercial spaces and industrial facilities, and more people working from home in Alliant Energy’s service territories. For 2020 and 2021, Alliant Energy, IPL and WPL considered the impact of COVID-19 on their overall business operations, financial condition, results of operations and cash flows, along with assumptions and estimates used. In 2020, Alliant Energy, IPL and WPL experienced higher electric residential sales and lower electric commercial and industrial sales as a result of the pandemic. In 2021, changes in COVID-19 impacts resulted in lower electric residential sales and higher electric commercial and industrial sales. The degree to which the COVID-19 pandemic may impact Alliant Energy, IPL and WPL in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities.

Basis of Presentation - The financial statements reflect investments in controlled subsidiaries on a consolidated basis and Alliant Energy’s, IPL’s and WPL’s proportionate shares of jointly-owned utility EGUs. Unconsolidated investments that Alliant Energy and WPL do not control are accounted for under the equity method of accounting. Under the equity method of accounting, Alliant Energy and WPL initially record the investment at cost, and adjust the carrying amount of the investment to recognize their respective share of the earnings or losses of the investee. Dividends received from an investee reduce the carrying amount of the equity investment. Investments that do not meet the criteria for consolidation or the equity method of accounting are accounted for under the cost method.

All intercompany balances and transactions, other than certain transactions affecting the rate-making process at IPL and WPL, have been eliminated from the financial statements. Such transactions not eliminated include costs that are recoverable from customers through rate-making processes. The financial statements are prepared in conformity with GAAP, which give recognition to the rate-making practices of FERC and state commissions having regulatory jurisdiction.

Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.

Use of Estimates - The preparation of the financial statements requires management to make estimates and assumptions that affect: (a) the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements; and (b) the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

(b) Regulatory Assets and Regulatory Liabilities - Alliant Energy, IPL and WPL are subject to regulation by FERC and various state regulatory commissions. As a result, Alliant Energy, IPL and WPL are subject to GAAP provisions for regulated operations, which provide that rate-regulated public utilities record certain costs and credits allowed in the rate-making process in different periods than for non-utility entities. Regulatory assets generally represent incurred costs that have been deferred as such costs are probable of recovery in future customer rates. Regulatory liabilities generally represent obligations to make refunds to customers or amounts collected in rates for which the related costs have not yet been incurred. Amounts recorded as regulatory assets or regulatory liabilities are generally recognized in the income statements at the time they are reflected in rates.(c) Income Taxes - The liability method of accounting is followed for deferred taxes, which requires the establishment of deferred tax assets and liabilities, as appropriate, for temporary differences between the tax basis of assets and liabilities and the amounts reported in the financial statements. Deferred taxes are recorded using currently enacted tax rates and estimates of state apportionment. Changes in deferred tax assets and liabilities associated with certain property-related differences at IPL are accounted for differently than other subsidiaries of Alliant Energy due to rate-making practices in Iowa. Rate-making practices in Iowa do not allow the impact of certain deferred tax expenses (benefits) to be included in the determination of retail rates. Based on these rate-making practices, deferred tax expense (benefit) related to these property-related differences at IPL is not recorded in the income statement but instead recorded to regulatory assets or regulatory liabilities until these temporary differences reverse. In Wisconsin, the PSCW allows rate recovery of deferred tax expense on all temporary differences.

Investment tax credits are deferred and amortized to income over the average lives of the related property. Federal Tax Reform repealed corporate federal alternative minimum tax and allowed unutilized alternative minimum tax credits to be refunded over four tax years beginning with the U.S. federal tax return for calendar year 2018. Pursuant to the Coronavirus Aid, Relief, and Economic Security Act, Alliant Energy received the remaining alternative minimum tax credits refunds in 2020. Other tax credits reduce income tax expense in the year claimed.

Alliant Energy files a consolidated federal income tax return and a combined return in Wisconsin, which include Alliant Energy and its subsidiaries. Alliant Energy subsidiaries with a presence in Iowa file as part of a consolidated return in Iowa.

Alliant Energy allocates consolidated income tax expense to its subsidiaries that are members of the group that file a consolidated or combined income tax return. IPL and WPL use the modified separate return approach for calculating their income tax provisions and related deferred tax assets and liabilities. IPL and WPL are assumed to file separate tax returns with the federal and state taxing authorities, except that net operating losses (and other current or deferred tax attributes) are characterized as realized (or realizable) by IPL and WPL when those tax attributes are realized (or realizable) by the consolidated tax return group of Alliant Energy (even if IPL and WPL would not otherwise have realized the attributes on a stand-alone basis). The difference in the income taxes recorded for IPL and WPL under the modified separate return method compared to the income taxes recorded on a separate return basis was not material in 2021, 2020 and 2019.

(d) Cash, Cash Equivalents and Restricted Cash - Cash and cash equivalents include short-term liquid investments that have original maturities of less than 90 days. At December 31, 2021, Alliant Energy’s and IPL’s cash and cash equivalents included $32 million of money market fund investments, with an interest rate of 0.04%. At December 31, 2021 and 2020, Alliant Energy’s restricted cash related to requirements in Sheboygan Power, LLC’s debt agreement.(e) Property, Plant and Equipment -

Utility Plant -

General - Utility plant is recorded at the original cost of acquisition or construction, which includes material, labor, contractor services, AFUDC and allocable overheads, such as supervision, engineering, benefits, certain taxes and transportation. Repairs, replacements and renewals of items of property determined to be less than a unit of property or that do not increase the property’s life or functionality are charged to maintenance expense. Property, plant and equipment that is probable of being retired early is classified as plant anticipated to be retired early. Generally, ordinary retirements of utility plant and salvage value are netted and charged to accumulated depreciation upon removal from utility plant accounts and no gain or loss is recognized consistent with rate-making principles. However, if regulators have approved recovery of the remaining net book value of property, plant and equipment that is retired early, or such approval by regulators is probable, the remaining net book value is reclassified from property, plant and equipment to regulatory assets upon retirement.

Depreciation - IPL and WPL use a combination of remaining life and straight-line depreciation methods as approved by their respective regulatory commissions. The composite or group method of depreciation is used, in which a single depreciation rate is applied to the gross investment in a particular class of property. This method pools similar assets and then depreciates each group as a whole. Periodic depreciation studies are performed to determine the appropriate group lives, net salvage, estimated cost of removal and group depreciation rates. These depreciation studies are subject to review and approval by IPL’s and WPL’s respective regulatory commissions. Depreciation expense is included within the recoverable cost of service component of rates collected from customers. The average rates of depreciation for electric, gas and other properties, consistent with current rate-making practices, were as follows:

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Electric - generation	3.4%	3.5%	3.8%	3.5%	3.5%	3.6%
Electric - distribution	2.9%	2.8%	2.9%	2.6%	2.6%	2.6%
Electric - other	5.7%	5.2%	5.3%	7.4%	6.1%	5.8%
Gas	3.3%	3.3%	3.3%	2.4%	2.4%	2.5%
Other	6.1%	6.3%	5.9%	5.4%	5.9%	5.6%

AFUDC - AFUDC represents costs to finance construction additions, including a return on equity component and cost of debt component as required by regulatory accounting. AFUDC for IPL’s construction projects is calculated in accordance with FERC guidelines. AFUDC for WPL’s retail and wholesale jurisdiction construction projects is calculated in accordance with PSCW and FERC guidelines, respectively. The AFUDC rates, computed in accordance with the prescribed regulatory formula, were as follows:

	2021	2020	2019
IPL (Wind generation CWIP)	7.0%	7.1%	7.4%
IPL (other CWIP)	7.2%	7.2%	7.5%
WPL (retail jurisdiction)	7.0%	7.0%	6.8%
WPL (wholesale jurisdiction)	5.6%	6.3%	6.9%

In accordance with their respective regulatory commission decisions, IPL applies its AFUDC rates to 100% of applicable CWIP balances and WPL generally applies its AFUDC rates to 50% of applicable CWIP balances. WPL may apply its AFUDC rates to 100% of the retail portion of the CWIP balances for construction projects requiring a CA or CPCN that were approved by the PSCW after its then most recent rate order, including West Riverside and the first and second solar generation CAs.

Non-utility and Other Property -

General - Non-utility property is recorded at the original cost of acquisition or construction, which includes material, labor and contractor services. Repairs, replacements and renewals of items of property determined to be less than a unit of property or that do not increase the property’s life or functionality are charged to maintenance expense. Upon retirement or sale of non-utility property, the original cost and related accumulated depreciation are removed from the accounts and any gain or loss is included in the income statements.

Costs related to software developed or obtained for internal use are capitalized and amortized on a straight-line basis over the estimated useful life of the related software. If software is retired prior to being fully amortized, the remaining book value is recorded as a loss in the income statements.

(f) Revenue Recognition -

Utility - Revenues from Alliant Energy’s utility business are primarily from electric and gas sales to customers. Utility revenues are recognized over time as services are rendered or commodities are delivered to customers, and include billed and unbilled components. The billed component is based on the reading of customers’ meters, which occurs on a systematic basis throughout each reporting period and represents the fair value of the services provided or commodities delivered. The unbilled component is estimated and recorded at the end of each reporting period based on estimated amounts of energy delivered to customers since the end of each customer’s last billing period. The unbilled component is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates.

IPL and WPL accrue revenues from their wholesale customers to the extent that the actual net revenue requirements calculated in accordance with FERC-approved formula rates for the reporting period are higher or lower than the amounts billed to wholesale customers during such period. Regulatory assets or regulatory liabilities are recorded as the offset for these accrued revenues under formulaic rate-making programs. As of December 31, 2021, the related amounts accrued for IPL and WPL were not material.

IPL and WPL participate in bid/offer-based wholesale energy and ancillary services markets operated by MISO. The MISO transactions are grouped together, resulting in a net supply to or net purchase from MISO for each hour of each day. The net supply to MISO is recorded as bulk power sales in “Electric utility revenues” and the net purchase from MISO is recorded in “Electric production fuel and purchased power” in the income statements.

Non-utility - Revenues from Alliant Energy’s non-utility businesses are primarily from its Travero business and are recognized over time as services are rendered to customers.

Taxes Collected from Customers - Sales or various other taxes collected by certain of Alliant Energy’s subsidiaries on behalf of other agencies are recorded on a net basis and are not included in revenues.

Other - Alliant Energy, IPL and WPL do not disclose the value of unsatisfied performance obligations for: (i) contracts with an original expected length of one year or less; and (ii) contracts for which revenue is recognized at the amount to which they have the right to invoice for services performed.(g) Utility Cost Recovery Mechanisms

Electric Production Fuel and Purchased Power (Fuel-related Costs) - Fuel-related costs are incurred to generate and purchase electricity to meet the demand of IPL’s and WPL’s electric customers. These fuel-related costs include the cost of fossil fuels (primarily natural gas and coal) used to produce electricity at their EGUs, and electricity purchased from MISO wholesale energy markets and under PPAs. These fuel-related costs are recorded in “Electric production fuel and purchased power” in the income statements.

IPL Retail - The cost recovery mechanisms for IPL’s retail electric customers provide for monthly adjustments to their electric rates for changes in fuel-related costs. Changes in the under-/over-collection of these costs are recognized in “Electric production fuel and purchased power” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

WPL Retail - The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. If WPL’s actual fuel-related costs fall outside these fuel monitoring ranges, WPL is authorized to defer the incremental under-/over-collection of fuel-related costs that are outside the approved ranges. Deferral of under-collections are reduced to the extent actual return on common equity earned by WPL during the fuel cost plan year exceeds the most recently authorized return on common equity. Deferred amounts for fuel-related costs outside the approved fuel monitoring ranges are recognized in “Electric production fuel and purchased power” in Alliant Energy’s and WPL’s income statements. The cumulative effects of these deferred amounts are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and WPL’s balance sheets until they are reflected in future billings to customers.

IPL and WPL Wholesale - The cost recovery mechanisms for IPL’s and WPL’s wholesale electric customers provide for subsequent adjustments to their electric rates for changes in fuel-related costs. Changes in the under-/over-collection of these costs are recognized in “Electric production fuel and purchased power” in the income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Purchased Electric Capacity - PPAs help meet the electricity demand of IPL’s and WPL’s customers. Certain PPAs include minimum payments for IPL’s and WPL’s rights to electric generating capacity, which are charged each period to “Electric production fuel and purchased power” in the income statements. Purchased electric capacity expenses are recovered from IPL’s and WPL’s retail electric customers through changes in base rates determined during periodic rate proceedings. Purchased electric capacity expenses are recovered from IPL’s and WPL’s wholesale electric customers through annual changes in base rates determined by a formula rate structure.

Electric Transmission Service - Costs incurred for the transmission of electricity to meet the demands of IPL’s and WPL’s customers are charged to “Electric transmission service” in the income statements.

IPL Retail - Electric transmission service expense is recovered from IPL’s retail electric customers through a transmission cost rider. This cost recovery mechanism provides for periodic adjustments to electric rates charged to retail electric customers for changes in electric transmission service expense. Changes in the under-/over-collection of these costs are recognized in “Electric transmission service” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

WPL Retail - Electric transmission service expense is recovered from WPL’s retail electric customers through changes in base rates determined during periodic rate proceedings. Pursuant to escrow accounting treatment approved by the PSCW, the difference between actual electric transmission service expense incurred and the amount of electric transmission service costs collected from customers as electric revenues is recognized in “Electric transmission service” in Alliant Energy’s and WPL’s income statements. An offsetting amount is recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and WPL’s balance sheets until reflected in future billings to customers.

IPL and WPL Wholesale - IPL and WPL arrange transmission service for the majority of their respective wholesale electric customers. Electric transmission service expense is allocated to and recovered from these customers based on a load ratio share computation.

Cost of Gas Sold - Costs are incurred for the purchase, transportation and storage of natural gas to serve IPL’s and WPL’s gas customers and the costs associated with the natural gas delivered to customers are charged to “Cost of gas sold” in the income statements. The tariffs for IPL’s and WPL’s retail gas customers provide for subsequent adjustments to their rates periodically for changes in the cost of gas sold. Changes in the under-/over-collection of these costs are also recognized in “Cost of gas sold” in the income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Energy Efficiency Costs - Costs incurred to fund energy efficiency programs and initiatives that help customers reduce their energy usage are charged to “Other operation and maintenance” in the income statements. Energy efficiency costs incurred by IPL are recovered from its retail electric and gas customers through energy efficiency and demand response cost recovery factor tariffs, which are revised annually and include a reconciliation to eliminate any under-/over-collection of energy efficiency costs from prior periods. Energy efficiency costs incurred by WPL are recovered from retail electric and gas customers through changes in base rates determined during periodic rate proceedings. Reconciliations of any under-/over-collection of energy efficiency costs from prior periods are also addressed in WPL’s periodic rate proceedings. Changes in the under-/over-collection of energy efficiency costs for IPL and WPL are recognized in “Other operation and maintenance” in the income statements. The cumulative effects of the under-/over-collection of these costs for IPL and WPL are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Renewable Energy Rider - Effective with the implementation of final rates covering the 2020 forward-looking Test Period, IPL recovers a return of, as well as earn a return on, its new wind generation placed in service in 2019 and 2020 from its retail electric customers through a renewable energy rider. Other applicable costs and tax benefits associated with the new wind generation, excluding operation and maintenance expenses, are also included in the rider. This cost recovery mechanism provides for annual adjustments to electric rates charged to IPL’s retail electric customers for actual renewable energy costs and tax benefits. Changes in the under-/over-collection of these costs are recognized in “Electric utility revenue” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs for IPL are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

(h) Financial Instruments - Financial instruments are periodically used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. The fair value of those financial instruments that are determined to be derivatives are recorded as assets or liabilities on the balance sheets. Certain commodity purchase and sales contracts qualified for and were designated under the normal purchase and sale exception, and were accounted for on the accrual basis of accounting. Alliant Energy, IPL and WPL have elected to not net the fair value amounts of derivatives subject to a master netting arrangement by counterparty. Alliant Energy, IPL and WPL do not offset fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) against fair value amounts recognized for derivative instruments that are executed with the same counterparty under the same master netting arrangement. Refer to Note 2 for discussion of the recognition of regulatory assets and regulatory liabilities related to the unrealized losses and gains on derivative instruments. Refer to Notes 15, 16 and 17(f) for further discussion of derivatives and related credit risk.(i) Asset Impairments -

Property, Plant and Equipment of Regulated Operations - Property, plant and equipment of regulated operations are reviewed for possible impairment whenever events or changes in circumstances indicate all or a portion of the carrying value of the assets may be disallowed for rate-making purposes. If IPL or WPL are disallowed recovery of any portion of, or are only allowed a partial return on, the carrying value of their regulated property, plant and equipment that is under construction, has been recently completed or is probable of abandonment, or conclude it is probable recovery or a full return will be disallowed, then an impairment charge is recognized.

Property, Plant and Equipment of Non-utility Operations - Property, plant and equipment of non-utility operations are reviewed for possible impairment whenever events or changes in circumstances indicate the carrying value of the assets may not be recoverable. Impairment is indicated if the carrying value of an asset exceeds its undiscounted future cash flows. If an impairment is indicated, a charge is recognized equal to the amount the carrying value exceeds the asset’s fair value.

Unconsolidated Equity Investments - If events or circumstances indicate the carrying value of investments accounted for under the equity method of accounting exceeds fair value and the decline in value is other than temporary, potential impairment is assessed. If an impairment is indicated, a charge is recognized equal to the amount the carrying value exceeds the investment’s fair value.

(j) Asset Retirement Obligations - The fair value of a legal obligation associated with the retirement of an asset is recorded as a liability when an asset is placed in service, when a legal obligation is subsequently identified or when sufficient information becomes available to determine a reasonable estimate of the fair value of future retirement costs. When an ARO is recorded as a liability, an equivalent amount is added to the asset cost. The fair value of AROs at inception is determined using discounted cash flows analyses. The liability is accreted to its present value and the capitalized cost is depreciated over the useful life of the related asset. Accretion and depreciation expenses related to AROs for IPL’s and WPL’s regulated operations are recorded to regulatory assets on the balance sheets. Revisions in estimated cash flows for IPL’s and WPL’s regulated operations are recorded as an increase or decrease to the ARO liability, with an offset to the asset cost, unless the asset is already retired and then the offset is recorded to regulatory assets or regulatory liabilities on the balance sheets. Upon regulatory approval to recover IPL’s AROs expenditures, its regulatory assets are amortized to depreciation and amortization expenses in Alliant Energy’s and IPL’s income statements over the same time period the ARO expenditures are recovered from IPL’s customers. WPL’s regulatory assets related to AROs are recovered as a component of depreciation rates pursuant to PSCW and FERC orders. Upon settlement of the ARO liability, an entity settles the obligation for its recorded amount or incurs a gain or loss. Any gains or losses related to AROs for IPL’s and WPL’s regulated operations are recorded to regulatory liabilities or regulatory assets on the balance sheets.(k) Debt Issuance and Retirement Costs - Debt issuance costs and debt premiums or discounts are presented on the balance sheets as a direct adjustment to the carrying amount of the related debt liability, and are deferred and amortized over the expected life of each debt issue, considering maturity dates and, if applicable, redemption rights held by others. Alliant Energy’s non-utility businesses and Corporate Services record to interest expense in the period of retirement any unamortized debt issuance costs and debt premiums or discounts on debt retired early.(l) Current Expected Credit Losses Estimates - Current expected credit losses are estimated for trade and other receivables and credit exposures on guarantees of the performance by third parties. The current expected credit losses for short-term trade receivables are based on estimates of losses resulting from the inability of customers to make required payments. The methodology used to estimate losses is based on historical write-offs, regional economic conditions, significant events that could impact collectability, such as impacts related to COVID-19, significant weather related matters including the derecho windstorm and related regulatory actions, and forecasted changes to the accounts receivable aging portfolio and write-offs. The current expected credit losses related to guarantees of the performance by third parties are estimated using both quantitative and qualitative information, which utilizes potential outcomes in a range of possible estimated amounts.In 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 17(d) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s equity statement for 2020.(m) Variable Interest Entities - An entity is considered a VIE if its equity investors do not have sufficient equity at risk for the entity to finance its activities without additional subordinated financial support from other parties, the entity is structured with disproportionate voting rights and substantially all of the entity’s activities are conducted on behalf of the investor with disproportionately fewer voting rights, or its equity investors lack any of the following characteristics: (1) power, through voting rights or similar rights, to direct the activities of the entity that most significantly impact the entity’s economic performance; (2) the obligation to absorb expected losses of the entity; or (3) the right to receive expected benefits of the entity. The primary beneficiary of a VIE is required to consolidate the VIE. The financial statements do not reflect any consolidation of VIEs.(n) Leases - The determination of whether an arrangement qualifies as a lease occurs at the inception of the arrangement. Arrangements that qualify as leases are classified as either operating or finance. Operating and finance lease liabilities represent obligations to make payments arising from the lease. Operating and finance lease assets represent the right to use an underlying asset for the lease term and are recognized at the lease commencement date based on the present value of the lease payments over the lease term. Leases with initial terms less than 12 months are not recognized as leases. For operating leases, an incremental borrowing rate, as determined at the lease commencement date, is used to determine the present value of the lease payments. For finance leases, the rate implicit in the lease, if known, is used to determine the present value of the lease payments. If the rate implicit in the lease is not known, the incremental borrowing rate is used to determine the present value of the lease payments. Lease terms include options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Operating lease expense is recognized on a straight-line basis over the expected lease term. Finance lease expense is comprised of depreciation and amortization, and interest expenses. Finance lease assets related to leased land for solar generation are amortized on a straight-line basis over the lease term, and are accounted for as operating leases for rate-making purposes. All other finance lease assets are depreciated on a straight-line basis over the shorter of the useful life of the underlying asset or the lease term.

WPL [Member]

Summary Of Significant Accounting Policies

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES(a) General -

Description of Business - Alliant Energy’s financial statements include the accounts of Alliant Energy and its consolidated subsidiaries. Alliant Energy is a Midwest U.S. energy holding company, whose primary wholly-owned subsidiaries are IPL, WPL, AEF and Corporate Services.

IPL’s financial statements include the accounts of IPL and its consolidated subsidiaries, including IPL SPE LLC, which is used for IPL’s sales of accounts receivable program. IPL is a direct subsidiary of Alliant Energy and is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Iowa. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa, and is engaged in the generation and distribution of steam for two customers in Cedar Rapids, Iowa.

WPL’s financial statements include the accounts of WPL and its consolidated subsidiary. WPL is a direct subsidiary of Alliant Energy and is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Wisconsin. WPL also sells electricity to wholesale customers in Wisconsin.

AEF is comprised of Travero, ATI, corporate venture investments, a non-utility wind farm, the Sheboygan Falls Energy Facility and other non-utility holdings. Travero includes a short-line rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; freight brokerage services; and a rail-served warehouse in Iowa, which began operations in 2021. ATI, a wholly-owned subsidiary of AEF, holds all of Alliant Energy’s interest in ATC Holdings. Corporate venture investments includes various minority ownership interests in regional and national venture funds, including a coalition with different energy companies across the U.S., working together to help identify and research innovative products, technologies and business models within the emerging energy economy. The non-utility wind farm includes a 50% cash equity ownership interest in a 225 MW wind farm located in Oklahoma. The Sheboygan Falls Energy Facility is a 347 MW, simple-cycle, natural gas-fired EGU near Sheboygan Falls, Wisconsin, which is leased to WPL for an initial period of 20 years ending in 2025.

Corporate Services is the subsidiary formed to provide administrative services to Alliant Energy and its subsidiaries.

In March 2020, COVID-19 was declared a global pandemic, which has resulted in widespread travel restrictions, closures of commercial spaces and industrial facilities, and more people working from home in Alliant Energy’s service territories. For 2020 and 2021, Alliant Energy, IPL and WPL considered the impact of COVID-19 on their overall business operations, financial condition, results of operations and cash flows, along with assumptions and estimates used. In 2020, Alliant Energy, IPL and WPL experienced higher electric residential sales and lower electric commercial and industrial sales as a result of the pandemic. In 2021, changes in COVID-19 impacts resulted in lower electric residential sales and higher electric commercial and industrial sales. The degree to which the COVID-19 pandemic may impact Alliant Energy, IPL and WPL in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities.

Basis of Presentation - The financial statements reflect investments in controlled subsidiaries on a consolidated basis and Alliant Energy’s, IPL’s and WPL’s proportionate shares of jointly-owned utility EGUs. Unconsolidated investments that Alliant Energy and WPL do not control are accounted for under the equity method of accounting. Under the equity method of accounting, Alliant Energy and WPL initially record the investment at cost, and adjust the carrying amount of the investment to recognize their respective share of the earnings or losses of the investee. Dividends received from an investee reduce the carrying amount of the equity investment. Investments that do not meet the criteria for consolidation or the equity method of accounting are accounted for under the cost method.

All intercompany balances and transactions, other than certain transactions affecting the rate-making process at IPL and WPL, have been eliminated from the financial statements. Such transactions not eliminated include costs that are recoverable from customers through rate-making processes. The financial statements are prepared in conformity with GAAP, which give recognition to the rate-making practices of FERC and state commissions having regulatory jurisdiction.

Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.

Use of Estimates - The preparation of the financial statements requires management to make estimates and assumptions that affect: (a) the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements; and (b) the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

(b) Regulatory Assets and Regulatory Liabilities - Alliant Energy, IPL and WPL are subject to regulation by FERC and various state regulatory commissions. As a result, Alliant Energy, IPL and WPL are subject to GAAP provisions for regulated operations, which provide that rate-regulated public utilities record certain costs and credits allowed in the rate-making process in different periods than for non-utility entities. Regulatory assets generally represent incurred costs that have been deferred as such costs are probable of recovery in future customer rates. Regulatory liabilities generally represent obligations to make refunds to customers or amounts collected in rates for which the related costs have not yet been incurred. Amounts recorded as regulatory assets or regulatory liabilities are generally recognized in the income statements at the time they are reflected in rates.(c) Income Taxes - The liability method of accounting is followed for deferred taxes, which requires the establishment of deferred tax assets and liabilities, as appropriate, for temporary differences between the tax basis of assets and liabilities and the amounts reported in the financial statements. Deferred taxes are recorded using currently enacted tax rates and estimates of state apportionment. Changes in deferred tax assets and liabilities associated with certain property-related differences at IPL are accounted for differently than other subsidiaries of Alliant Energy due to rate-making practices in Iowa. Rate-making practices in Iowa do not allow the impact of certain deferred tax expenses (benefits) to be included in the determination of retail rates. Based on these rate-making practices, deferred tax expense (benefit) related to these property-related differences at IPL is not recorded in the income statement but instead recorded to regulatory assets or regulatory liabilities until these temporary differences reverse. In Wisconsin, the PSCW allows rate recovery of deferred tax expense on all temporary differences.

Investment tax credits are deferred and amortized to income over the average lives of the related property. Federal Tax Reform repealed corporate federal alternative minimum tax and allowed unutilized alternative minimum tax credits to be refunded over four tax years beginning with the U.S. federal tax return for calendar year 2018. Pursuant to the Coronavirus Aid, Relief, and Economic Security Act, Alliant Energy received the remaining alternative minimum tax credits refunds in 2020. Other tax credits reduce income tax expense in the year claimed.

Alliant Energy files a consolidated federal income tax return and a combined return in Wisconsin, which include Alliant Energy and its subsidiaries. Alliant Energy subsidiaries with a presence in Iowa file as part of a consolidated return in Iowa.

Alliant Energy allocates consolidated income tax expense to its subsidiaries that are members of the group that file a consolidated or combined income tax return. IPL and WPL use the modified separate return approach for calculating their income tax provisions and related deferred tax assets and liabilities. IPL and WPL are assumed to file separate tax returns with the federal and state taxing authorities, except that net operating losses (and other current or deferred tax attributes) are characterized as realized (or realizable) by IPL and WPL when those tax attributes are realized (or realizable) by the consolidated tax return group of Alliant Energy (even if IPL and WPL would not otherwise have realized the attributes on a stand-alone basis). The difference in the income taxes recorded for IPL and WPL under the modified separate return method compared to the income taxes recorded on a separate return basis was not material in 2021, 2020 and 2019.

(d) Cash, Cash Equivalents and Restricted Cash - Cash and cash equivalents include short-term liquid investments that have original maturities of less than 90 days. At December 31, 2021, Alliant Energy’s and IPL’s cash and cash equivalents included $32 million of money market fund investments, with an interest rate of 0.04%. At December 31, 2021 and 2020, Alliant Energy’s restricted cash related to requirements in Sheboygan Power, LLC’s debt agreement.(e) Property, Plant and Equipment -

Utility Plant -

General - Utility plant is recorded at the original cost of acquisition or construction, which includes material, labor, contractor services, AFUDC and allocable overheads, such as supervision, engineering, benefits, certain taxes and transportation. Repairs, replacements and renewals of items of property determined to be less than a unit of property or that do not increase the property’s life or functionality are charged to maintenance expense. Property, plant and equipment that is probable of being retired early is classified as plant anticipated to be retired early. Generally, ordinary retirements of utility plant and salvage value are netted and charged to accumulated depreciation upon removal from utility plant accounts and no gain or loss is recognized consistent with rate-making principles. However, if regulators have approved recovery of the remaining net book value of property, plant and equipment that is retired early, or such approval by regulators is probable, the remaining net book value is reclassified from property, plant and equipment to regulatory assets upon retirement.

Depreciation - IPL and WPL use a combination of remaining life and straight-line depreciation methods as approved by their respective regulatory commissions. The composite or group method of depreciation is used, in which a single depreciation rate is applied to the gross investment in a particular class of property. This method pools similar assets and then depreciates each group as a whole. Periodic depreciation studies are performed to determine the appropriate group lives, net salvage, estimated cost of removal and group depreciation rates. These depreciation studies are subject to review and approval by IPL’s and WPL’s respective regulatory commissions. Depreciation expense is included within the recoverable cost of service component of rates collected from customers. The average rates of depreciation for electric, gas and other properties, consistent with current rate-making practices, were as follows:

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Electric - generation	3.4%	3.5%	3.8%	3.5%	3.5%	3.6%
Electric - distribution	2.9%	2.8%	2.9%	2.6%	2.6%	2.6%
Electric - other	5.7%	5.2%	5.3%	7.4%	6.1%	5.8%
Gas	3.3%	3.3%	3.3%	2.4%	2.4%	2.5%
Other	6.1%	6.3%	5.9%	5.4%	5.9%	5.6%

AFUDC - AFUDC represents costs to finance construction additions, including a return on equity component and cost of debt component as required by regulatory accounting. AFUDC for IPL’s construction projects is calculated in accordance with FERC guidelines. AFUDC for WPL’s retail and wholesale jurisdiction construction projects is calculated in accordance with PSCW and FERC guidelines, respectively. The AFUDC rates, computed in accordance with the prescribed regulatory formula, were as follows:

	2021	2020	2019
IPL (Wind generation CWIP)	7.0%	7.1%	7.4%
IPL (other CWIP)	7.2%	7.2%	7.5%
WPL (retail jurisdiction)	7.0%	7.0%	6.8%
WPL (wholesale jurisdiction)	5.6%	6.3%	6.9%

In accordance with their respective regulatory commission decisions, IPL applies its AFUDC rates to 100% of applicable CWIP balances and WPL generally applies its AFUDC rates to 50% of applicable CWIP balances. WPL may apply its AFUDC rates to 100% of the retail portion of the CWIP balances for construction projects requiring a CA or CPCN that were approved by the PSCW after its then most recent rate order, including West Riverside and the first and second solar generation CAs.

Non-utility and Other Property -

General - Non-utility property is recorded at the original cost of acquisition or construction, which includes material, labor and contractor services. Repairs, replacements and renewals of items of property determined to be less than a unit of property or that do not increase the property’s life or functionality are charged to maintenance expense. Upon retirement or sale of non-utility property, the original cost and related accumulated depreciation are removed from the accounts and any gain or loss is included in the income statements.

Costs related to software developed or obtained for internal use are capitalized and amortized on a straight-line basis over the estimated useful life of the related software. If software is retired prior to being fully amortized, the remaining book value is recorded as a loss in the income statements.

(f) Revenue Recognition -

Utility - Revenues from Alliant Energy’s utility business are primarily from electric and gas sales to customers. Utility revenues are recognized over time as services are rendered or commodities are delivered to customers, and include billed and unbilled components. The billed component is based on the reading of customers’ meters, which occurs on a systematic basis throughout each reporting period and represents the fair value of the services provided or commodities delivered. The unbilled component is estimated and recorded at the end of each reporting period based on estimated amounts of energy delivered to customers since the end of each customer’s last billing period. The unbilled component is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates.

IPL and WPL accrue revenues from their wholesale customers to the extent that the actual net revenue requirements calculated in accordance with FERC-approved formula rates for the reporting period are higher or lower than the amounts billed to wholesale customers during such period. Regulatory assets or regulatory liabilities are recorded as the offset for these accrued revenues under formulaic rate-making programs. As of December 31, 2021, the related amounts accrued for IPL and WPL were not material.

IPL and WPL participate in bid/offer-based wholesale energy and ancillary services markets operated by MISO. The MISO transactions are grouped together, resulting in a net supply to or net purchase from MISO for each hour of each day. The net supply to MISO is recorded as bulk power sales in “Electric utility revenues” and the net purchase from MISO is recorded in “Electric production fuel and purchased power” in the income statements.

Non-utility - Revenues from Alliant Energy’s non-utility businesses are primarily from its Travero business and are recognized over time as services are rendered to customers.

Taxes Collected from Customers - Sales or various other taxes collected by certain of Alliant Energy’s subsidiaries on behalf of other agencies are recorded on a net basis and are not included in revenues.

Other - Alliant Energy, IPL and WPL do not disclose the value of unsatisfied performance obligations for: (i) contracts with an original expected length of one year or less; and (ii) contracts for which revenue is recognized at the amount to which they have the right to invoice for services performed.(g) Utility Cost Recovery Mechanisms

Electric Production Fuel and Purchased Power (Fuel-related Costs) - Fuel-related costs are incurred to generate and purchase electricity to meet the demand of IPL’s and WPL’s electric customers. These fuel-related costs include the cost of fossil fuels (primarily natural gas and coal) used to produce electricity at their EGUs, and electricity purchased from MISO wholesale energy markets and under PPAs. These fuel-related costs are recorded in “Electric production fuel and purchased power” in the income statements.

IPL Retail - The cost recovery mechanisms for IPL’s retail electric customers provide for monthly adjustments to their electric rates for changes in fuel-related costs. Changes in the under-/over-collection of these costs are recognized in “Electric production fuel and purchased power” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

WPL Retail - The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. If WPL’s actual fuel-related costs fall outside these fuel monitoring ranges, WPL is authorized to defer the incremental under-/over-collection of fuel-related costs that are outside the approved ranges. Deferral of under-collections are reduced to the extent actual return on common equity earned by WPL during the fuel cost plan year exceeds the most recently authorized return on common equity. Deferred amounts for fuel-related costs outside the approved fuel monitoring ranges are recognized in “Electric production fuel and purchased power” in Alliant Energy’s and WPL’s income statements. The cumulative effects of these deferred amounts are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and WPL’s balance sheets until they are reflected in future billings to customers.

IPL and WPL Wholesale - The cost recovery mechanisms for IPL’s and WPL’s wholesale electric customers provide for subsequent adjustments to their electric rates for changes in fuel-related costs. Changes in the under-/over-collection of these costs are recognized in “Electric production fuel and purchased power” in the income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Purchased Electric Capacity - PPAs help meet the electricity demand of IPL’s and WPL’s customers. Certain PPAs include minimum payments for IPL’s and WPL’s rights to electric generating capacity, which are charged each period to “Electric production fuel and purchased power” in the income statements. Purchased electric capacity expenses are recovered from IPL’s and WPL’s retail electric customers through changes in base rates determined during periodic rate proceedings. Purchased electric capacity expenses are recovered from IPL’s and WPL’s wholesale electric customers through annual changes in base rates determined by a formula rate structure.

Electric Transmission Service - Costs incurred for the transmission of electricity to meet the demands of IPL’s and WPL’s customers are charged to “Electric transmission service” in the income statements.

IPL Retail - Electric transmission service expense is recovered from IPL’s retail electric customers through a transmission cost rider. This cost recovery mechanism provides for periodic adjustments to electric rates charged to retail electric customers for changes in electric transmission service expense. Changes in the under-/over-collection of these costs are recognized in “Electric transmission service” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

WPL Retail - Electric transmission service expense is recovered from WPL’s retail electric customers through changes in base rates determined during periodic rate proceedings. Pursuant to escrow accounting treatment approved by the PSCW, the difference between actual electric transmission service expense incurred and the amount of electric transmission service costs collected from customers as electric revenues is recognized in “Electric transmission service” in Alliant Energy’s and WPL’s income statements. An offsetting amount is recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and WPL’s balance sheets until reflected in future billings to customers.

IPL and WPL Wholesale - IPL and WPL arrange transmission service for the majority of their respective wholesale electric customers. Electric transmission service expense is allocated to and recovered from these customers based on a load ratio share computation.

Cost of Gas Sold - Costs are incurred for the purchase, transportation and storage of natural gas to serve IPL’s and WPL’s gas customers and the costs associated with the natural gas delivered to customers are charged to “Cost of gas sold” in the income statements. The tariffs for IPL’s and WPL’s retail gas customers provide for subsequent adjustments to their rates periodically for changes in the cost of gas sold. Changes in the under-/over-collection of these costs are also recognized in “Cost of gas sold” in the income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Energy Efficiency Costs - Costs incurred to fund energy efficiency programs and initiatives that help customers reduce their energy usage are charged to “Other operation and maintenance” in the income statements. Energy efficiency costs incurred by IPL are recovered from its retail electric and gas customers through energy efficiency and demand response cost recovery factor tariffs, which are revised annually and include a reconciliation to eliminate any under-/over-collection of energy efficiency costs from prior periods. Energy efficiency costs incurred by WPL are recovered from retail electric and gas customers through changes in base rates determined during periodic rate proceedings. Reconciliations of any under-/over-collection of energy efficiency costs from prior periods are also addressed in WPL’s periodic rate proceedings. Changes in the under-/over-collection of energy efficiency costs for IPL and WPL are recognized in “Other operation and maintenance” in the income statements. The cumulative effects of the under-/over-collection of these costs for IPL and WPL are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Renewable Energy Rider - Effective with the implementation of final rates covering the 2020 forward-looking Test Period, IPL recovers a return of, as well as earn a return on, its new wind generation placed in service in 2019 and 2020 from its retail electric customers through a renewable energy rider. Other applicable costs and tax benefits associated with the new wind generation, excluding operation and maintenance expenses, are also included in the rider. This cost recovery mechanism provides for annual adjustments to electric rates charged to IPL’s retail electric customers for actual renewable energy costs and tax benefits. Changes in the under-/over-collection of these costs are recognized in “Electric utility revenue” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs for IPL are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

(h) Financial Instruments - Financial instruments are periodically used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. The fair value of those financial instruments that are determined to be derivatives are recorded as assets or liabilities on the balance sheets. Certain commodity purchase and sales contracts qualified for and were designated under the normal purchase and sale exception, and were accounted for on the accrual basis of accounting. Alliant Energy, IPL and WPL have elected to not net the fair value amounts of derivatives subject to a master netting arrangement by counterparty. Alliant Energy, IPL and WPL do not offset fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) against fair value amounts recognized for derivative instruments that are executed with the same counterparty under the same master netting arrangement. Refer to Note 2 for discussion of the recognition of regulatory assets and regulatory liabilities related to the unrealized losses and gains on derivative instruments. Refer to Notes 15, 16 and 17(f) for further discussion of derivatives and related credit risk.(i) Asset Impairments -

Property, Plant and Equipment of Regulated Operations - Property, plant and equipment of regulated operations are reviewed for possible impairment whenever events or changes in circumstances indicate all or a portion of the carrying value of the assets may be disallowed for rate-making purposes. If IPL or WPL are disallowed recovery of any portion of, or are only allowed a partial return on, the carrying value of their regulated property, plant and equipment that is under construction, has been recently completed or is probable of abandonment, or conclude it is probable recovery or a full return will be disallowed, then an impairment charge is recognized.

Property, Plant and Equipment of Non-utility Operations - Property, plant and equipment of non-utility operations are reviewed for possible impairment whenever events or changes in circumstances indicate the carrying value of the assets may not be recoverable. Impairment is indicated if the carrying value of an asset exceeds its undiscounted future cash flows. If an impairment is indicated, a charge is recognized equal to the amount the carrying value exceeds the asset’s fair value.

Unconsolidated Equity Investments - If events or circumstances indicate the carrying value of investments accounted for under the equity method of accounting exceeds fair value and the decline in value is other than temporary, potential impairment is assessed. If an impairment is indicated, a charge is recognized equal to the amount the carrying value exceeds the investment’s fair value.

(j) Asset Retirement Obligations - The fair value of a legal obligation associated with the retirement of an asset is recorded as a liability when an asset is placed in service, when a legal obligation is subsequently identified or when sufficient information becomes available to determine a reasonable estimate of the fair value of future retirement costs. When an ARO is recorded as a liability, an equivalent amount is added to the asset cost. The fair value of AROs at inception is determined using discounted cash flows analyses. The liability is accreted to its present value and the capitalized cost is depreciated over the useful life of the related asset. Accretion and depreciation expenses related to AROs for IPL’s and WPL’s regulated operations are recorded to regulatory assets on the balance sheets. Revisions in estimated cash flows for IPL’s and WPL’s regulated operations are recorded as an increase or decrease to the ARO liability, with an offset to the asset cost, unless the asset is already retired and then the offset is recorded to regulatory assets or regulatory liabilities on the balance sheets. Upon regulatory approval to recover IPL’s AROs expenditures, its regulatory assets are amortized to depreciation and amortization expenses in Alliant Energy’s and IPL’s income statements over the same time period the ARO expenditures are recovered from IPL’s customers. WPL’s regulatory assets related to AROs are recovered as a component of depreciation rates pursuant to PSCW and FERC orders. Upon settlement of the ARO liability, an entity settles the obligation for its recorded amount or incurs a gain or loss. Any gains or losses related to AROs for IPL’s and WPL’s regulated operations are recorded to regulatory liabilities or regulatory assets on the balance sheets.(k) Debt Issuance and Retirement Costs - Debt issuance costs and debt premiums or discounts are presented on the balance sheets as a direct adjustment to the carrying amount of the related debt liability, and are deferred and amortized over the expected life of each debt issue, considering maturity dates and, if applicable, redemption rights held by others. Alliant Energy’s non-utility businesses and Corporate Services record to interest expense in the period of retirement any unamortized debt issuance costs and debt premiums or discounts on debt retired early.(l) Current Expected Credit Losses Estimates - Current expected credit losses are estimated for trade and other receivables and credit exposures on guarantees of the performance by third parties. The current expected credit losses for short-term trade receivables are based on estimates of losses resulting from the inability of customers to make required payments. The methodology used to estimate losses is based on historical write-offs, regional economic conditions, significant events that could impact collectability, such as impacts related to COVID-19, significant weather related matters including the derecho windstorm and related regulatory actions, and forecasted changes to the accounts receivable aging portfolio and write-offs. The current expected credit losses related to guarantees of the performance by third parties are estimated using both quantitative and qualitative information, which utilizes potential outcomes in a range of possible estimated amounts.In 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 17(d) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s equity statement for 2020.(m) Variable Interest Entities - An entity is considered a VIE if its equity investors do not have sufficient equity at risk for the entity to finance its activities without additional subordinated financial support from other parties, the entity is structured with disproportionate voting rights and substantially all of the entity’s activities are conducted on behalf of the investor with disproportionately fewer voting rights, or its equity investors lack any of the following characteristics: (1) power, through voting rights or similar rights, to direct the activities of the entity that most significantly impact the entity’s economic performance; (2) the obligation to absorb expected losses of the entity; or (3) the right to receive expected benefits of the entity. The primary beneficiary of a VIE is required to consolidate the VIE. The financial statements do not reflect any consolidation of VIEs.(n) Leases - The determination of whether an arrangement qualifies as a lease occurs at the inception of the arrangement. Arrangements that qualify as leases are classified as either operating or finance. Operating and finance lease liabilities represent obligations to make payments arising from the lease. Operating and finance lease assets represent the right to use an underlying asset for the lease term and are recognized at the lease commencement date based on the present value of the lease payments over the lease term. Leases with initial terms less than 12 months are not recognized as leases. For operating leases, an incremental borrowing rate, as determined at the lease commencement date, is used to determine the present value of the lease payments. For finance leases, the rate implicit in the lease, if known, is used to determine the present value of the lease payments. If the rate implicit in the lease is not known, the incremental borrowing rate is used to determine the present value of the lease payments. Lease terms include options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Operating lease expense is recognized on a straight-line basis over the expected lease term. Finance lease expense is comprised of depreciation and amortization, and interest expenses. Finance lease assets related to leased land for solar generation are amortized on a straight-line basis over the lease term, and are accounted for as operating leases for rate-making purposes. All other finance lease assets are depreciated on a straight-line basis over the shorter of the useful life of the underlying asset or the lease term.

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Regulatory Matters

12 Months Ended

Dec. 31, 2021

Regulatory Matters [Line Items]

Regulatory Matters

REGULATORY MATTERS

Regulatory Assets - Alliant Energy, IPL and WPL assess whether IPL’s and WPL’s regulatory assets are probable of future recovery by considering factors such as applicable regulations, recent orders by the applicable regulatory agencies, historical treatment of similar costs by the applicable regulatory agencies and regulatory environment changes. Based on these assessments, Alliant Energy, IPL and WPL believe the regulatory assets recognized as of December 31, 2021 are probable of future recovery. However, no assurance can be made that IPL and WPL will recover all of these regulatory assets in future rates. If future recovery of a regulatory asset ceases to be probable, the regulatory asset will be charged to expense. At December 31, regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Tax-related	$934	$890	$884	$843	$50	$47
Pension and OPEB costs	462	580	228	291	234	289
AROs	128	119	89	81	39	38
Assets retired early	92	113	66	77	26	36
IPL’s DAEC PPA amendment	90	110	90	110	—	—
WPL’s Western Wisconsin gas distribution expansion investments	52	55	—	—	52	55
Commodity cost recovery	42	4	2	1	40	3
Derivatives	8	26	4	13	4	13
Other	132	113	80	67	52	46
	$1,940	$2,010	$1,443	$1,483	$497	$527

At December 31, 2021, IPL and WPL had $75 million and $13 million, respectively, of regulatory assets that were not earning a return. IPL’s regulatory assets that were not earning a return consisted primarily of retired analog electric meters, emission allowances and costs for certain construction projects. WPL’s regulatory assets that were not earning a return consisted primarily of amounts related to the wholesale portion of under-collected costs, and costs for future expansion projects. The other regulatory assets reported in the above table either earn a return or the cash has not yet been expended, in which case the assets are offset by liabilities that also do not incur a carrying cost.

Tax-related - IPL and WPL record regulatory assets for certain temporary differences (primarily related to utility property, plant and equipment at IPL) that result in a decrease in current rates charged to customers and an increase in future rates charged to customers based on the timing of income tax expense that is used to determine such rates. These temporary differences for IPL include the impacts of qualifying deductions for repairs expenditures, allocation of mixed service costs, and Iowa accelerated tax depreciation, which all contribute to lower current income tax expense during the first part of an asset’s useful life and higher current income tax expense during the latter part of an asset’s useful life. These regulatory assets will be recovered from customers in the future when these temporary differences reverse resulting in additional current income tax expense used to determine customers’ rates.

Pension and other postretirement benefits costs - The IUB, PSCW and FERC have authorized IPL and WPL to record the previously unrecognized net actuarial gains and losses, and prior service costs and credits, as regulatory assets in lieu of accumulated other comprehensive loss on the balance sheets, as these amounts are expected to be recovered in future rates. These regulatory assets will be increased or decreased as the net actuarial gains or losses, and prior service costs or credits, are subsequently amortized and recognized as a component of net periodic benefit costs. Regulatory assets are also increased or decreased as a result of the annual defined benefit plan measurement process. Pension and OPEB costs are included within the recoverable cost of service component of rates charged to IPL’s and WPL’s retail and wholesale customers, which are based upon pension and OPEB costs determined in accordance with GAAP and are calculated in accordance with IPL’s and WPL’s respective regulatory jurisdictions.

AROs - Alliant Energy, IPL and WPL believe it is probable that certain differences between expenses accrued for AROs related to their utility operations and expenses recovered currently in rates will be recoverable in future rates, and are deferring the differences as regulatory assets.

Assets retired early - IPL and WPL have retired various natural gas- and coal-fired EGUs, and IPL has retired certain analog electric meters. As a result, the remaining net book value of these assets was reclassified from property, plant and equipment to a regulatory asset on their respective balance sheets. Details regarding the recovery of the remaining net book value of these assets from IPL’s and WPL’s customers are as follows (dollars in millions):

Entity	Asset	Retirement Date	Regulatory Asset Balance as of Dec. 31, 2021	Recovery	Regulatory Approval
IPL	Sutherland Units 1 and 3	2017	$19	Return of and return on remaining net book value through 2027	IUB and FERC
IPL	M.L. Kapp Unit 2	2018	18	Return of and return on remaining net book value through 2029	IUB and FERC
IPL	Analog electric meters	2019	29	Return of remaining net book value through 2028	IUB and FERC
WPL	Nelson Dewey Units 1 and 2 and Edgewater Unit 3	2015	6	Return of and return on remaining net book value through 2022	PSCW and FERC
WPL	Edgewater Unit 4	2018	20	Return of and return on remaining net book value through 2028	PSCW and FERC

IPL’s DAEC PPA Amendment - In September 2020, IPL made a buyout payment of $110 million in exchange for shortening the term of its DAEC PPA by 5 years. The payment was included in “DAEC PPA amendment buyout payment” in Alliant Energy’s and IPL’s cash flows used for operating activities in 2020. The buyout payment, including a return on, will be recovered from IPL’s retail and wholesale customers from 2021 through the end of 2025, and is currently being amortized to “Electric production fuel and purchased power” in Alliant Energy’s and IPL’s income statements.

WPL’s Western Wisconsin gas distribution expansion investments - WPL made contributions in aid of construction to a third party for investments as part of its Western Wisconsin gas distribution expansion project. Pursuant to authorization by the PSCW, Alliant Energy and WPL have recorded a regulatory asset for these costs, and are authorized by the PSCW to recover these amounts from WPL’s retail gas customers in base rates from 2021 through the end of 2040.

Commodity cost recovery - Refer to Note 1(g) for details of IPL’s and WPL’s commodity cost recovery mechanisms. The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. In 2021, WPL’s actual fuel-related costs fell outside these fuel monitoring ranges, resulting in a $37 million deferral as of December 31, 2021.

Derivatives - In accordance with IPL’s and WPL’s fuel and natural gas recovery mechanisms, prudently incurred costs from derivative instruments are recoverable from customers in the future after any losses are realized, and gains from derivative instruments are refundable to customers in the future after any gains are realized. Based on these recovery mechanisms, the changes in the fair value of derivative liabilities/assets resulted in comparable changes to regulatory assets/liabilities on the balance sheets.

Regulatory Liabilities - At December 31, regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Tax-related	$585	$732	$312	$331	$273	$401
Cost of removal obligations	384	367	252	238	132	129
Derivatives	166	28	77	25	89	3
Electric transmission cost recovery	51	68	27	39	24	29
WPL’s West Riverside liquidated damages	36	38	—	—	36	38
Other	49	73	23	43	26	30
	$1,271	$1,306	$691	$676	$580	$630

Tax-related regulatory liabilities reduce revenue requirement calculations utilized in IPL’s and WPL’s respective rate proceedings. Cost of removal obligations, to the extent expensed through depreciation rates, reduce rate base. A significant portion of the remaining regulatory liabilities is not used to adjust revenue requirement calculations.

Tax-related - Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities are primarily related to excess deferred tax benefits resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform. The majority of these benefits related to accelerated depreciation are subject to tax normalization rules. These rules limit the rate at which these tax benefits are allowed to be passed on to customers. In 2021, Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities decreased primarily due to returning a portion of these excess deferred tax benefits back to customers.

Cost of removal obligations - Alliant Energy, IPL and WPL collect in rates future removal costs for many assets that do not have associated AROs or that have removal costs in addition to AROs. Alliant Energy, IPL and WPL record a regulatory liability for the amounts collected in rates for these future removal costs and reduce the regulatory liability for amounts spent on removal activities. Cash payments related to cost of removal obligations are included in “Other” in cash flows used for investing activities.

Electric transmission cost recovery - Refer to Note 1(g) for details of IPL’s and WPL’s electric transmission cost recovery mechanisms. In 2020, pursuant to an IUB order, IPL issued $42 million of credits to its retail electric customers through its transmission cost rider for amounts previously collected in rates, which resulted in a reduction to “Electric transmission service” expense in Alliant Energy’s and IPL’s income statements in 2020.

WPL’s West Riverside liquidated damages - Pursuant to terms included in the related West Riverside construction procurement contracts, WPL reached agreement with the contractor on liquidated damages in 2020. A significant portion of the liquidated damages was settled by WPL offsetting amounts owed to the contractor that were previously withheld for payment, which were non-cash investing activities. In December 2020, the PSCW authorized WPL to record the liquidated damages as a regulatory liability, which the PSCW authorized to be returned to WPL’s retail customers in 2022 and 2023.

Derecho Windstorm - In August 2020, a derecho windstorm caused considerable damage to IPL’s electric distribution system in its service territory, and over 250,000 of its customers lost power. IPL completed its initial restoration and rebuilding efforts in August 2020 and permanent repairs to the system continue. As of December 31, 2021, approximately $140 million of costs from the windstorm were recorded substantially to “Property, plant and equipment, net” on Alliant Energy’s and IPL’s balance sheets. In December 2020, IPL received approval from the IUB for utilization of a regulatory account to track certain incremental costs and benefits incurred resulting from the windstorm. These incremental costs and benefits were not addressed in the IUB’s order for IPL’s 2020 forward-looking Test Period electric subsequent proceeding, and are expected to be addressed in future regulatory proceedings. Tax benefits and the incremental operation and maintenance expenses resulting from the windstorm were deferred and recorded as a net regulatory liability of $8 million as of December 31, 2021, which is included in “Other” regulatory liabilities in the above table.

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. In October 2019, IPL reached a settlement agreement with certain intervenor groups for an annual retail electric base rate increase of $127 million. In January 2020, the IUB issued an order approving the settlement with final rates, which were effective February 26, 2020. 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. In addition, as discussed in Note 1(g), the net impact of certain costs and benefits resulting from IPL’s 1,000 MW expansion of wind generation in 2019 and 2020 is being recovered from its retail electric customers through the renewable energy rider. The agreement also includes IPL providing retail electric billing credits, which began in the third quarter of 2020 through June 2021, and in aggregate include $27 million of excess deferred tax benefits and $8 million from a partial refund of interim rates implemented in 2019. In 2021, the IUB issued an order for IPL’s 2020 forward-looking Test Period electric subsequent proceeding, which compared actual revenues and costs to those initially forecasted by IPL, and authorized IPL to maintain its current retail electric rates.

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. In October 2019, IPL reached a settlement agreement with intervenor groups for an annual retail gas base rate increase of $12 million. In December 2019, the IUB issued an order approving the settlement with final rates, which were effective January 10, 2020. In 2021, the IUB issued an order for IPL’s 2020 forward-looking Test Period gas subsequent proceeding, which compared actual revenues and costs to those initially forecasted by IPL, and authorized IPL to maintain its current retail gas rates.

WPL’s Retail Electric and Gas Rate Review (2019/2020 Forward-looking Test Period) - In December 2018, the PSCW issued an order approving WPL’s proposed settlement for its retail electric and gas rate review covering the 2019/2020 Test Period, which was based on a stipulated agreement between WPL and intervenor groups. Under the settlement, WPL retail electric and gas base rates did not change from then current levels through the end of 2020. In September 2020, pursuant to an August 2020 PSCW order, WPL refunded $12 million of 2019 fuel-related cost over-collections to its retail electric customers. In addition, WPL’s amortization of excess deferred taxes resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform was used to offset increases in WPL’s 2020 increased revenue requirements.

WPL’s Retail Electric and Gas Rate Review (2021 Forward-looking Test Period) - In December 2020, the PSCW issued an order authorizing WPL to maintain its then current retail electric and gas base rates, authorized return on common equity, regulatory capital structure and earnings sharing mechanism through the end of 2021. WPL utilized anticipated fuel-related cost savings and excess deferred income tax benefits in 2021 to offset the revenue requirement impacts of increasing electric and gas rate base, including the Kossuth wind farm, which was placed in service in October 2020, and the expansion of its gas distribution system in Western Wisconsin, which was placed in service in November 2020.

WPL’s Retail Fuel-related Rate Filing (2020 Forward-looking Test Period) - In December 2019, WPL received an order from the PSCW authorizing an annual retail electric rate decrease of $29 million, or approximately 2%, effective January 1, 2020. The decrease primarily reflected a change in expected fuel-related costs in 2020.

IPL [Member]

Regulatory Matters [Line Items]

Regulatory Matters

REGULATORY MATTERS

Regulatory Assets - Alliant Energy, IPL and WPL assess whether IPL’s and WPL’s regulatory assets are probable of future recovery by considering factors such as applicable regulations, recent orders by the applicable regulatory agencies, historical treatment of similar costs by the applicable regulatory agencies and regulatory environment changes. Based on these assessments, Alliant Energy, IPL and WPL believe the regulatory assets recognized as of December 31, 2021 are probable of future recovery. However, no assurance can be made that IPL and WPL will recover all of these regulatory assets in future rates. If future recovery of a regulatory asset ceases to be probable, the regulatory asset will be charged to expense. At December 31, regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Tax-related	$934	$890	$884	$843	$50	$47
Pension and OPEB costs	462	580	228	291	234	289
AROs	128	119	89	81	39	38
Assets retired early	92	113	66	77	26	36
IPL’s DAEC PPA amendment	90	110	90	110	—	—
WPL’s Western Wisconsin gas distribution expansion investments	52	55	—	—	52	55
Commodity cost recovery	42	4	2	1	40	3
Derivatives	8	26	4	13	4	13
Other	132	113	80	67	52	46
	$1,940	$2,010	$1,443	$1,483	$497	$527

At December 31, 2021, IPL and WPL had $75 million and $13 million, respectively, of regulatory assets that were not earning a return. IPL’s regulatory assets that were not earning a return consisted primarily of retired analog electric meters, emission allowances and costs for certain construction projects. WPL’s regulatory assets that were not earning a return consisted primarily of amounts related to the wholesale portion of under-collected costs, and costs for future expansion projects. The other regulatory assets reported in the above table either earn a return or the cash has not yet been expended, in which case the assets are offset by liabilities that also do not incur a carrying cost.

Tax-related - IPL and WPL record regulatory assets for certain temporary differences (primarily related to utility property, plant and equipment at IPL) that result in a decrease in current rates charged to customers and an increase in future rates charged to customers based on the timing of income tax expense that is used to determine such rates. These temporary differences for IPL include the impacts of qualifying deductions for repairs expenditures, allocation of mixed service costs, and Iowa accelerated tax depreciation, which all contribute to lower current income tax expense during the first part of an asset’s useful life and higher current income tax expense during the latter part of an asset’s useful life. These regulatory assets will be recovered from customers in the future when these temporary differences reverse resulting in additional current income tax expense used to determine customers’ rates.

Pension and other postretirement benefits costs - The IUB, PSCW and FERC have authorized IPL and WPL to record the previously unrecognized net actuarial gains and losses, and prior service costs and credits, as regulatory assets in lieu of accumulated other comprehensive loss on the balance sheets, as these amounts are expected to be recovered in future rates. These regulatory assets will be increased or decreased as the net actuarial gains or losses, and prior service costs or credits, are subsequently amortized and recognized as a component of net periodic benefit costs. Regulatory assets are also increased or decreased as a result of the annual defined benefit plan measurement process. Pension and OPEB costs are included within the recoverable cost of service component of rates charged to IPL’s and WPL’s retail and wholesale customers, which are based upon pension and OPEB costs determined in accordance with GAAP and are calculated in accordance with IPL’s and WPL’s respective regulatory jurisdictions.

AROs - Alliant Energy, IPL and WPL believe it is probable that certain differences between expenses accrued for AROs related to their utility operations and expenses recovered currently in rates will be recoverable in future rates, and are deferring the differences as regulatory assets.

Assets retired early - IPL and WPL have retired various natural gas- and coal-fired EGUs, and IPL has retired certain analog electric meters. As a result, the remaining net book value of these assets was reclassified from property, plant and equipment to a regulatory asset on their respective balance sheets. Details regarding the recovery of the remaining net book value of these assets from IPL’s and WPL’s customers are as follows (dollars in millions):

Entity	Asset	Retirement Date	Regulatory Asset Balance as of Dec. 31, 2021	Recovery	Regulatory Approval
IPL	Sutherland Units 1 and 3	2017	$19	Return of and return on remaining net book value through 2027	IUB and FERC
IPL	M.L. Kapp Unit 2	2018	18	Return of and return on remaining net book value through 2029	IUB and FERC
IPL	Analog electric meters	2019	29	Return of remaining net book value through 2028	IUB and FERC
WPL	Nelson Dewey Units 1 and 2 and Edgewater Unit 3	2015	6	Return of and return on remaining net book value through 2022	PSCW and FERC
WPL	Edgewater Unit 4	2018	20	Return of and return on remaining net book value through 2028	PSCW and FERC

IPL’s DAEC PPA Amendment - In September 2020, IPL made a buyout payment of $110 million in exchange for shortening the term of its DAEC PPA by 5 years. The payment was included in “DAEC PPA amendment buyout payment” in Alliant Energy’s and IPL’s cash flows used for operating activities in 2020. The buyout payment, including a return on, will be recovered from IPL’s retail and wholesale customers from 2021 through the end of 2025, and is currently being amortized to “Electric production fuel and purchased power” in Alliant Energy’s and IPL’s income statements.

WPL’s Western Wisconsin gas distribution expansion investments - WPL made contributions in aid of construction to a third party for investments as part of its Western Wisconsin gas distribution expansion project. Pursuant to authorization by the PSCW, Alliant Energy and WPL have recorded a regulatory asset for these costs, and are authorized by the PSCW to recover these amounts from WPL’s retail gas customers in base rates from 2021 through the end of 2040.

Commodity cost recovery - Refer to Note 1(g) for details of IPL’s and WPL’s commodity cost recovery mechanisms. The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. In 2021, WPL’s actual fuel-related costs fell outside these fuel monitoring ranges, resulting in a $37 million deferral as of December 31, 2021.

Derivatives - In accordance with IPL’s and WPL’s fuel and natural gas recovery mechanisms, prudently incurred costs from derivative instruments are recoverable from customers in the future after any losses are realized, and gains from derivative instruments are refundable to customers in the future after any gains are realized. Based on these recovery mechanisms, the changes in the fair value of derivative liabilities/assets resulted in comparable changes to regulatory assets/liabilities on the balance sheets.

Regulatory Liabilities - At December 31, regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Tax-related	$585	$732	$312	$331	$273	$401
Cost of removal obligations	384	367	252	238	132	129
Derivatives	166	28	77	25	89	3
Electric transmission cost recovery	51	68	27	39	24	29
WPL’s West Riverside liquidated damages	36	38	—	—	36	38
Other	49	73	23	43	26	30
	$1,271	$1,306	$691	$676	$580	$630

Tax-related regulatory liabilities reduce revenue requirement calculations utilized in IPL’s and WPL’s respective rate proceedings. Cost of removal obligations, to the extent expensed through depreciation rates, reduce rate base. A significant portion of the remaining regulatory liabilities is not used to adjust revenue requirement calculations.

Tax-related - Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities are primarily related to excess deferred tax benefits resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform. The majority of these benefits related to accelerated depreciation are subject to tax normalization rules. These rules limit the rate at which these tax benefits are allowed to be passed on to customers. In 2021, Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities decreased primarily due to returning a portion of these excess deferred tax benefits back to customers.

Cost of removal obligations - Alliant Energy, IPL and WPL collect in rates future removal costs for many assets that do not have associated AROs or that have removal costs in addition to AROs. Alliant Energy, IPL and WPL record a regulatory liability for the amounts collected in rates for these future removal costs and reduce the regulatory liability for amounts spent on removal activities. Cash payments related to cost of removal obligations are included in “Other” in cash flows used for investing activities.

Electric transmission cost recovery - Refer to Note 1(g) for details of IPL’s and WPL’s electric transmission cost recovery mechanisms. In 2020, pursuant to an IUB order, IPL issued $42 million of credits to its retail electric customers through its transmission cost rider for amounts previously collected in rates, which resulted in a reduction to “Electric transmission service” expense in Alliant Energy’s and IPL’s income statements in 2020.

WPL’s West Riverside liquidated damages - Pursuant to terms included in the related West Riverside construction procurement contracts, WPL reached agreement with the contractor on liquidated damages in 2020. A significant portion of the liquidated damages was settled by WPL offsetting amounts owed to the contractor that were previously withheld for payment, which were non-cash investing activities. In December 2020, the PSCW authorized WPL to record the liquidated damages as a regulatory liability, which the PSCW authorized to be returned to WPL’s retail customers in 2022 and 2023.

Derecho Windstorm - In August 2020, a derecho windstorm caused considerable damage to IPL’s electric distribution system in its service territory, and over 250,000 of its customers lost power. IPL completed its initial restoration and rebuilding efforts in August 2020 and permanent repairs to the system continue. As of December 31, 2021, approximately $140 million of costs from the windstorm were recorded substantially to “Property, plant and equipment, net” on Alliant Energy’s and IPL’s balance sheets. In December 2020, IPL received approval from the IUB for utilization of a regulatory account to track certain incremental costs and benefits incurred resulting from the windstorm. These incremental costs and benefits were not addressed in the IUB’s order for IPL’s 2020 forward-looking Test Period electric subsequent proceeding, and are expected to be addressed in future regulatory proceedings. Tax benefits and the incremental operation and maintenance expenses resulting from the windstorm were deferred and recorded as a net regulatory liability of $8 million as of December 31, 2021, which is included in “Other” regulatory liabilities in the above table.

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. In October 2019, IPL reached a settlement agreement with certain intervenor groups for an annual retail electric base rate increase of $127 million. In January 2020, the IUB issued an order approving the settlement with final rates, which were effective February 26, 2020. 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. In addition, as discussed in Note 1(g), the net impact of certain costs and benefits resulting from IPL’s 1,000 MW expansion of wind generation in 2019 and 2020 is being recovered from its retail electric customers through the renewable energy rider. The agreement also includes IPL providing retail electric billing credits, which began in the third quarter of 2020 through June 2021, and in aggregate include $27 million of excess deferred tax benefits and $8 million from a partial refund of interim rates implemented in 2019. In 2021, the IUB issued an order for IPL’s 2020 forward-looking Test Period electric subsequent proceeding, which compared actual revenues and costs to those initially forecasted by IPL, and authorized IPL to maintain its current retail electric rates.

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. In October 2019, IPL reached a settlement agreement with intervenor groups for an annual retail gas base rate increase of $12 million. In December 2019, the IUB issued an order approving the settlement with final rates, which were effective January 10, 2020. In 2021, the IUB issued an order for IPL’s 2020 forward-looking Test Period gas subsequent proceeding, which compared actual revenues and costs to those initially forecasted by IPL, and authorized IPL to maintain its current retail gas rates.

WPL’s Retail Electric and Gas Rate Review (2019/2020 Forward-looking Test Period) - In December 2018, the PSCW issued an order approving WPL’s proposed settlement for its retail electric and gas rate review covering the 2019/2020 Test Period, which was based on a stipulated agreement between WPL and intervenor groups. Under the settlement, WPL retail electric and gas base rates did not change from then current levels through the end of 2020. In September 2020, pursuant to an August 2020 PSCW order, WPL refunded $12 million of 2019 fuel-related cost over-collections to its retail electric customers. In addition, WPL’s amortization of excess deferred taxes resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform was used to offset increases in WPL’s 2020 increased revenue requirements.

WPL’s Retail Electric and Gas Rate Review (2021 Forward-looking Test Period) - In December 2020, the PSCW issued an order authorizing WPL to maintain its then current retail electric and gas base rates, authorized return on common equity, regulatory capital structure and earnings sharing mechanism through the end of 2021. WPL utilized anticipated fuel-related cost savings and excess deferred income tax benefits in 2021 to offset the revenue requirement impacts of increasing electric and gas rate base, including the Kossuth wind farm, which was placed in service in October 2020, and the expansion of its gas distribution system in Western Wisconsin, which was placed in service in November 2020.

WPL’s Retail Fuel-related Rate Filing (2020 Forward-looking Test Period) - In December 2019, WPL received an order from the PSCW authorizing an annual retail electric rate decrease of $29 million, or approximately 2%, effective January 1, 2020. The decrease primarily reflected a change in expected fuel-related costs in 2020.

WPL [Member]

Regulatory Matters [Line Items]

Regulatory Matters

REGULATORY MATTERS

Regulatory Assets - Alliant Energy, IPL and WPL assess whether IPL’s and WPL’s regulatory assets are probable of future recovery by considering factors such as applicable regulations, recent orders by the applicable regulatory agencies, historical treatment of similar costs by the applicable regulatory agencies and regulatory environment changes. Based on these assessments, Alliant Energy, IPL and WPL believe the regulatory assets recognized as of December 31, 2021 are probable of future recovery. However, no assurance can be made that IPL and WPL will recover all of these regulatory assets in future rates. If future recovery of a regulatory asset ceases to be probable, the regulatory asset will be charged to expense. At December 31, regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Tax-related	$934	$890	$884	$843	$50	$47
Pension and OPEB costs	462	580	228	291	234	289
AROs	128	119	89	81	39	38
Assets retired early	92	113	66	77	26	36
IPL’s DAEC PPA amendment	90	110	90	110	—	—
WPL’s Western Wisconsin gas distribution expansion investments	52	55	—	—	52	55
Commodity cost recovery	42	4	2	1	40	3
Derivatives	8	26	4	13	4	13
Other	132	113	80	67	52	46
	$1,940	$2,010	$1,443	$1,483	$497	$527

At December 31, 2021, IPL and WPL had $75 million and $13 million, respectively, of regulatory assets that were not earning a return. IPL’s regulatory assets that were not earning a return consisted primarily of retired analog electric meters, emission allowances and costs for certain construction projects. WPL’s regulatory assets that were not earning a return consisted primarily of amounts related to the wholesale portion of under-collected costs, and costs for future expansion projects. The other regulatory assets reported in the above table either earn a return or the cash has not yet been expended, in which case the assets are offset by liabilities that also do not incur a carrying cost.

Tax-related - IPL and WPL record regulatory assets for certain temporary differences (primarily related to utility property, plant and equipment at IPL) that result in a decrease in current rates charged to customers and an increase in future rates charged to customers based on the timing of income tax expense that is used to determine such rates. These temporary differences for IPL include the impacts of qualifying deductions for repairs expenditures, allocation of mixed service costs, and Iowa accelerated tax depreciation, which all contribute to lower current income tax expense during the first part of an asset’s useful life and higher current income tax expense during the latter part of an asset’s useful life. These regulatory assets will be recovered from customers in the future when these temporary differences reverse resulting in additional current income tax expense used to determine customers’ rates.

Pension and other postretirement benefits costs - The IUB, PSCW and FERC have authorized IPL and WPL to record the previously unrecognized net actuarial gains and losses, and prior service costs and credits, as regulatory assets in lieu of accumulated other comprehensive loss on the balance sheets, as these amounts are expected to be recovered in future rates. These regulatory assets will be increased or decreased as the net actuarial gains or losses, and prior service costs or credits, are subsequently amortized and recognized as a component of net periodic benefit costs. Regulatory assets are also increased or decreased as a result of the annual defined benefit plan measurement process. Pension and OPEB costs are included within the recoverable cost of service component of rates charged to IPL’s and WPL’s retail and wholesale customers, which are based upon pension and OPEB costs determined in accordance with GAAP and are calculated in accordance with IPL’s and WPL’s respective regulatory jurisdictions.

AROs - Alliant Energy, IPL and WPL believe it is probable that certain differences between expenses accrued for AROs related to their utility operations and expenses recovered currently in rates will be recoverable in future rates, and are deferring the differences as regulatory assets.

Assets retired early - IPL and WPL have retired various natural gas- and coal-fired EGUs, and IPL has retired certain analog electric meters. As a result, the remaining net book value of these assets was reclassified from property, plant and equipment to a regulatory asset on their respective balance sheets. Details regarding the recovery of the remaining net book value of these assets from IPL’s and WPL’s customers are as follows (dollars in millions):

Entity	Asset	Retirement Date	Regulatory Asset Balance as of Dec. 31, 2021	Recovery	Regulatory Approval
IPL	Sutherland Units 1 and 3	2017	$19	Return of and return on remaining net book value through 2027	IUB and FERC
IPL	M.L. Kapp Unit 2	2018	18	Return of and return on remaining net book value through 2029	IUB and FERC
IPL	Analog electric meters	2019	29	Return of remaining net book value through 2028	IUB and FERC
WPL	Nelson Dewey Units 1 and 2 and Edgewater Unit 3	2015	6	Return of and return on remaining net book value through 2022	PSCW and FERC
WPL	Edgewater Unit 4	2018	20	Return of and return on remaining net book value through 2028	PSCW and FERC

IPL’s DAEC PPA Amendment - In September 2020, IPL made a buyout payment of $110 million in exchange for shortening the term of its DAEC PPA by 5 years. The payment was included in “DAEC PPA amendment buyout payment” in Alliant Energy’s and IPL’s cash flows used for operating activities in 2020. The buyout payment, including a return on, will be recovered from IPL’s retail and wholesale customers from 2021 through the end of 2025, and is currently being amortized to “Electric production fuel and purchased power” in Alliant Energy’s and IPL’s income statements.

WPL’s Western Wisconsin gas distribution expansion investments - WPL made contributions in aid of construction to a third party for investments as part of its Western Wisconsin gas distribution expansion project. Pursuant to authorization by the PSCW, Alliant Energy and WPL have recorded a regulatory asset for these costs, and are authorized by the PSCW to recover these amounts from WPL’s retail gas customers in base rates from 2021 through the end of 2040.

Commodity cost recovery - Refer to Note 1(g) for details of IPL’s and WPL’s commodity cost recovery mechanisms. The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. In 2021, WPL’s actual fuel-related costs fell outside these fuel monitoring ranges, resulting in a $37 million deferral as of December 31, 2021.

Derivatives - In accordance with IPL’s and WPL’s fuel and natural gas recovery mechanisms, prudently incurred costs from derivative instruments are recoverable from customers in the future after any losses are realized, and gains from derivative instruments are refundable to customers in the future after any gains are realized. Based on these recovery mechanisms, the changes in the fair value of derivative liabilities/assets resulted in comparable changes to regulatory assets/liabilities on the balance sheets.

Regulatory Liabilities - At December 31, regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Tax-related	$585	$732	$312	$331	$273	$401
Cost of removal obligations	384	367	252	238	132	129
Derivatives	166	28	77	25	89	3
Electric transmission cost recovery	51	68	27	39	24	29
WPL’s West Riverside liquidated damages	36	38	—	—	36	38
Other	49	73	23	43	26	30
	$1,271	$1,306	$691	$676	$580	$630

Tax-related regulatory liabilities reduce revenue requirement calculations utilized in IPL’s and WPL’s respective rate proceedings. Cost of removal obligations, to the extent expensed through depreciation rates, reduce rate base. A significant portion of the remaining regulatory liabilities is not used to adjust revenue requirement calculations.

Tax-related - Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities are primarily related to excess deferred tax benefits resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform. The majority of these benefits related to accelerated depreciation are subject to tax normalization rules. These rules limit the rate at which these tax benefits are allowed to be passed on to customers. In 2021, Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities decreased primarily due to returning a portion of these excess deferred tax benefits back to customers.

Cost of removal obligations - Alliant Energy, IPL and WPL collect in rates future removal costs for many assets that do not have associated AROs or that have removal costs in addition to AROs. Alliant Energy, IPL and WPL record a regulatory liability for the amounts collected in rates for these future removal costs and reduce the regulatory liability for amounts spent on removal activities. Cash payments related to cost of removal obligations are included in “Other” in cash flows used for investing activities.

Electric transmission cost recovery - Refer to Note 1(g) for details of IPL’s and WPL’s electric transmission cost recovery mechanisms. In 2020, pursuant to an IUB order, IPL issued $42 million of credits to its retail electric customers through its transmission cost rider for amounts previously collected in rates, which resulted in a reduction to “Electric transmission service” expense in Alliant Energy’s and IPL’s income statements in 2020.

WPL’s West Riverside liquidated damages - Pursuant to terms included in the related West Riverside construction procurement contracts, WPL reached agreement with the contractor on liquidated damages in 2020. A significant portion of the liquidated damages was settled by WPL offsetting amounts owed to the contractor that were previously withheld for payment, which were non-cash investing activities. In December 2020, the PSCW authorized WPL to record the liquidated damages as a regulatory liability, which the PSCW authorized to be returned to WPL’s retail customers in 2022 and 2023.

Derecho Windstorm - In August 2020, a derecho windstorm caused considerable damage to IPL’s electric distribution system in its service territory, and over 250,000 of its customers lost power. IPL completed its initial restoration and rebuilding efforts in August 2020 and permanent repairs to the system continue. As of December 31, 2021, approximately $140 million of costs from the windstorm were recorded substantially to “Property, plant and equipment, net” on Alliant Energy’s and IPL’s balance sheets. In December 2020, IPL received approval from the IUB for utilization of a regulatory account to track certain incremental costs and benefits incurred resulting from the windstorm. These incremental costs and benefits were not addressed in the IUB’s order for IPL’s 2020 forward-looking Test Period electric subsequent proceeding, and are expected to be addressed in future regulatory proceedings. Tax benefits and the incremental operation and maintenance expenses resulting from the windstorm were deferred and recorded as a net regulatory liability of $8 million as of December 31, 2021, which is included in “Other” regulatory liabilities in the above table.

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. In October 2019, IPL reached a settlement agreement with certain intervenor groups for an annual retail electric base rate increase of $127 million. In January 2020, the IUB issued an order approving the settlement with final rates, which were effective February 26, 2020. 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. In addition, as discussed in Note 1(g), the net impact of certain costs and benefits resulting from IPL’s 1,000 MW expansion of wind generation in 2019 and 2020 is being recovered from its retail electric customers through the renewable energy rider. The agreement also includes IPL providing retail electric billing credits, which began in the third quarter of 2020 through June 2021, and in aggregate include $27 million of excess deferred tax benefits and $8 million from a partial refund of interim rates implemented in 2019. In 2021, the IUB issued an order for IPL’s 2020 forward-looking Test Period electric subsequent proceeding, which compared actual revenues and costs to those initially forecasted by IPL, and authorized IPL to maintain its current retail electric rates.

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. In October 2019, IPL reached a settlement agreement with intervenor groups for an annual retail gas base rate increase of $12 million. In December 2019, the IUB issued an order approving the settlement with final rates, which were effective January 10, 2020. In 2021, the IUB issued an order for IPL’s 2020 forward-looking Test Period gas subsequent proceeding, which compared actual revenues and costs to those initially forecasted by IPL, and authorized IPL to maintain its current retail gas rates.

WPL’s Retail Electric and Gas Rate Review (2019/2020 Forward-looking Test Period) - In December 2018, the PSCW issued an order approving WPL’s proposed settlement for its retail electric and gas rate review covering the 2019/2020 Test Period, which was based on a stipulated agreement between WPL and intervenor groups. Under the settlement, WPL retail electric and gas base rates did not change from then current levels through the end of 2020. In September 2020, pursuant to an August 2020 PSCW order, WPL refunded $12 million of 2019 fuel-related cost over-collections to its retail electric customers. In addition, WPL’s amortization of excess deferred taxes resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform was used to offset increases in WPL’s 2020 increased revenue requirements.

WPL’s Retail Electric and Gas Rate Review (2021 Forward-looking Test Period) - In December 2020, the PSCW issued an order authorizing WPL to maintain its then current retail electric and gas base rates, authorized return on common equity, regulatory capital structure and earnings sharing mechanism through the end of 2021. WPL utilized anticipated fuel-related cost savings and excess deferred income tax benefits in 2021 to offset the revenue requirement impacts of increasing electric and gas rate base, including the Kossuth wind farm, which was placed in service in October 2020, and the expansion of its gas distribution system in Western Wisconsin, which was placed in service in November 2020.

WPL’s Retail Fuel-related Rate Filing (2020 Forward-looking Test Period) - In December 2019, WPL received an order from the PSCW authorizing an annual retail electric rate decrease of $29 million, or approximately 2%, effective January 1, 2020. The decrease primarily reflected a change in expected fuel-related costs in 2020.

XML

Property, Plant and Equipment

12 Months Ended

Dec. 31, 2021

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
	2021	2020	2021	2020	2021	2020
Utility:
Electric plant:
Generation in service	$7,539	$8,222	$4,922	$4,884	$2,617	$3,338
Distribution in service	6,537	6,216	3,652	3,470	2,885	2,746
Other in service	540	536	363	358	177	178
Anticipated to be retired early (a)	2,094	1,269	487	459	1,607	810
Total electric plant	16,710	16,243	9,424	9,171	7,286	7,072
Gas plant in service	1,636	1,563	878	844	758	719
Other plant in service	621	534	398	354	223	180
Accumulated depreciation	(5,263)	(4,868)	(2,897)	(2,671)	(2,366)	(2,197)
Net plant	13,704	13,472	7,803	7,698	5,901	5,774
Leased Sheboygan Falls Energy Facility, net (b)	—	—	—	—	21	27
Leased land for solar generation, net	11	—	—	—	11	—
Construction work in progress	778	405	174	185	604	220
Other, net	7	7	6	6	1	1
Total utility	14,500	13,884	7,983	7,889	6,538	6,022
Non-utility and other:
Non-utility Generation, net (c)	75	79	—	—	—	—
Corporate Services and other, net (d)	412	373	—	—	—	—
Total non-utility and other	487	452	—	—	—	—
Total property, plant and equipment	$14,987	$14,336	$7,983	$7,889	$6,538	$6,022

(a)In 2020, IPL and WPL received approval from MISO to retire Lansing and Edgewater Unit 5, respectively, and currently anticipate retiring Lansing by the end of 2022 and Edgewater Unit 5 by early 2023. In 2021, WPL received approval from MISO to retire Columbia Units 1 and 2, and currently anticipates retiring Columbia Unit 1 by the end of 2023 and Columbia Unit 2 by the end of 2024. Alliant Energy and IPL concluded that Lansing, and Alliant Energy and WPL concluded that Edgewater Unit 5 and Columbia Units 1 and 2, met the criteria to be considered probable of abandonment as of December 31, 2021. IPL and WPL are currently allowed a full recovery of and a full return on its respective EGUs from both its retail and wholesale customers, and as a result, Alliant Energy, IPL and WPL concluded that no disallowance was required as of December 31, 2021. As of December 31, 2021, net book values were $245 million for Lansing, $527 million for Edgewater Unit 5, and $460 million for Columbia Units 1 and 2 in aggregate.

(b)Less accumulated amortization of $100 million and $95 million for WPL as of December 31, 2021 and 2020, respectively. For Alliant Energy, the leased Sheboygan Falls Energy Facility is eliminated 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 $67 million and $63 million for Alliant Energy as of December 31, 2021 and 2020, respectively.

(d)Less accumulated depreciation of $245 million and $210 million for Alliant Energy as of December 31, 2021 and 2020, 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
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Equity	$18	$39	$66	$7	$17	$35	$11	$22	$31
Debt	7	16	27	2	7	15	5	9	12
	$25	$55	$93	$9	$24	$50	$16	$31	$43

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 in 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 rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; freight brokerage services; and a rail-served warehouse in Iowa, which began operations in 2021). 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
	2021	2020	2021	2020	2021	2020
Utility:
Electric plant:
Generation in service	$7,539	$8,222	$4,922	$4,884	$2,617	$3,338
Distribution in service	6,537	6,216	3,652	3,470	2,885	2,746
Other in service	540	536	363	358	177	178
Anticipated to be retired early (a)	2,094	1,269	487	459	1,607	810
Total electric plant	16,710	16,243	9,424	9,171	7,286	7,072
Gas plant in service	1,636	1,563	878	844	758	719
Other plant in service	621	534	398	354	223	180
Accumulated depreciation	(5,263)	(4,868)	(2,897)	(2,671)	(2,366)	(2,197)
Net plant	13,704	13,472	7,803	7,698	5,901	5,774
Leased Sheboygan Falls Energy Facility, net (b)	—	—	—	—	21	27
Leased land for solar generation, net	11	—	—	—	11	—
Construction work in progress	778	405	174	185	604	220
Other, net	7	7	6	6	1	1
Total utility	14,500	13,884	7,983	7,889	6,538	6,022
Non-utility and other:
Non-utility Generation, net (c)	75	79	—	—	—	—
Corporate Services and other, net (d)	412	373	—	—	—	—
Total non-utility and other	487	452	—	—	—	—
Total property, plant and equipment	$14,987	$14,336	$7,983	$7,889	$6,538	$6,022

(a)In 2020, IPL and WPL received approval from MISO to retire Lansing and Edgewater Unit 5, respectively, and currently anticipate retiring Lansing by the end of 2022 and Edgewater Unit 5 by early 2023. In 2021, WPL received approval from MISO to retire Columbia Units 1 and 2, and currently anticipates retiring Columbia Unit 1 by the end of 2023 and Columbia Unit 2 by the end of 2024. Alliant Energy and IPL concluded that Lansing, and Alliant Energy and WPL concluded that Edgewater Unit 5 and Columbia Units 1 and 2, met the criteria to be considered probable of abandonment as of December 31, 2021. IPL and WPL are currently allowed a full recovery of and a full return on its respective EGUs from both its retail and wholesale customers, and as a result, Alliant Energy, IPL and WPL concluded that no disallowance was required as of December 31, 2021. As of December 31, 2021, net book values were $245 million for Lansing, $527 million for Edgewater Unit 5, and $460 million for Columbia Units 1 and 2 in aggregate.

(b)Less accumulated amortization of $100 million and $95 million for WPL as of December 31, 2021 and 2020, respectively. For Alliant Energy, the leased Sheboygan Falls Energy Facility is eliminated 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 $67 million and $63 million for Alliant Energy as of December 31, 2021 and 2020, respectively.

(d)Less accumulated depreciation of $245 million and $210 million for Alliant Energy as of December 31, 2021 and 2020, 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
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Equity	$18	$39	$66	$7	$17	$35	$11	$22	$31
Debt	7	16	27	2	7	15	5	9	12
	$25	$55	$93	$9	$24	$50	$16	$31	$43

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
	2021	2020	2021	2020	2021	2020
Utility:
Electric plant:
Generation in service	$7,539	$8,222	$4,922	$4,884	$2,617	$3,338
Distribution in service	6,537	6,216	3,652	3,470	2,885	2,746
Other in service	540	536	363	358	177	178
Anticipated to be retired early (a)	2,094	1,269	487	459	1,607	810
Total electric plant	16,710	16,243	9,424	9,171	7,286	7,072
Gas plant in service	1,636	1,563	878	844	758	719
Other plant in service	621	534	398	354	223	180
Accumulated depreciation	(5,263)	(4,868)	(2,897)	(2,671)	(2,366)	(2,197)
Net plant	13,704	13,472	7,803	7,698	5,901	5,774
Leased Sheboygan Falls Energy Facility, net (b)	—	—	—	—	21	27
Leased land for solar generation, net	11	—	—	—	11	—
Construction work in progress	778	405	174	185	604	220
Other, net	7	7	6	6	1	1
Total utility	14,500	13,884	7,983	7,889	6,538	6,022
Non-utility and other:
Non-utility Generation, net (c)	75	79	—	—	—	—
Corporate Services and other, net (d)	412	373	—	—	—	—
Total non-utility and other	487	452	—	—	—	—
Total property, plant and equipment	$14,987	$14,336	$7,983	$7,889	$6,538	$6,022

(a)In 2020, IPL and WPL received approval from MISO to retire Lansing and Edgewater Unit 5, respectively, and currently anticipate retiring Lansing by the end of 2022 and Edgewater Unit 5 by early 2023. In 2021, WPL received approval from MISO to retire Columbia Units 1 and 2, and currently anticipates retiring Columbia Unit 1 by the end of 2023 and Columbia Unit 2 by the end of 2024. Alliant Energy and IPL concluded that Lansing, and Alliant Energy and WPL concluded that Edgewater Unit 5 and Columbia Units 1 and 2, met the criteria to be considered probable of abandonment as of December 31, 2021. IPL and WPL are currently allowed a full recovery of and a full return on its respective EGUs from both its retail and wholesale customers, and as a result, Alliant Energy, IPL and WPL concluded that no disallowance was required as of December 31, 2021. As of December 31, 2021, net book values were $245 million for Lansing, $527 million for Edgewater Unit 5, and $460 million for Columbia Units 1 and 2 in aggregate.

(b)Less accumulated amortization of $100 million and $95 million for WPL as of December 31, 2021 and 2020, respectively. For Alliant Energy, the leased Sheboygan Falls Energy Facility is eliminated 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 $67 million and $63 million for Alliant Energy as of December 31, 2021 and 2020, respectively.

(d)Less accumulated depreciation of $245 million and $210 million for Alliant Energy as of December 31, 2021 and 2020, 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
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Equity	$18	$39	$66	$7	$17	$35	$11	$22	$31
Debt	7	16	27	2	7	15	5	9	12
	$25	$55	$93	$9	$24	$50	$16	$31	$43

XML

Jointly-Owned Electric Utility Plant

12 Months Ended

Dec. 31, 2021

Jointly-Owned Electric Utility Plant

JOINTLY-OWNED ELECTRIC UTILITY PLANT

Under joint ownership agreements with other utilities, IPL and WPL have undivided ownership interests in jointly-owned EGUs. Each of the respective owners is responsible for the financing of its portion of the construction costs. IPL’s and WPL’s shares of expenses from jointly-owned EGUs are included in the corresponding operating expenses (e.g., electric production fuel, other operation and maintenance, etc.) in the income statements. Information relative to IPL’s and WPL’s ownership interest in these jointly-owned EGUs at December 31, 2021 was as follows (dollars in millions):

	Ownership	Electric	Accumulated Provision	Construction
	Interest %	Plant	for Depreciation	Work in Progress
IPL
Ottumwa Unit 1	48.0%	$599	$214	$11
George Neal Unit 4	25.7%	193	100	2
George Neal Unit 3	28.0%	173	74	3
Louisa Unit 1	4.0%	40	23	—
		1,005	411	16
WPL
Columbia Units 1-2	53.5%	802	314	6
West Riverside Energy Center and Solar Garden	91.0%	706	33	3
Forward Wind Energy Center	42.6%	118	48	—
		1,626	395	9
Alliant Energy		$2,631	$806	$25

IPL [Member]

Jointly-Owned Electric Utility Plant

JOINTLY-OWNED ELECTRIC UTILITY PLANT

Under joint ownership agreements with other utilities, IPL and WPL have undivided ownership interests in jointly-owned EGUs. Each of the respective owners is responsible for the financing of its portion of the construction costs. IPL’s and WPL’s shares of expenses from jointly-owned EGUs are included in the corresponding operating expenses (e.g., electric production fuel, other operation and maintenance, etc.) in the income statements. Information relative to IPL’s and WPL’s ownership interest in these jointly-owned EGUs at December 31, 2021 was as follows (dollars in millions):

	Ownership	Electric	Accumulated Provision	Construction
	Interest %	Plant	for Depreciation	Work in Progress
IPL
Ottumwa Unit 1	48.0%	$599	$214	$11
George Neal Unit 4	25.7%	193	100	2
George Neal Unit 3	28.0%	173	74	3
Louisa Unit 1	4.0%	40	23	—
		1,005	411	16
WPL
Columbia Units 1-2	53.5%	802	314	6
West Riverside Energy Center and Solar Garden	91.0%	706	33	3
Forward Wind Energy Center	42.6%	118	48	—
		1,626	395	9
Alliant Energy		$2,631	$806	$25

WPL [Member]

Jointly-Owned Electric Utility Plant

JOINTLY-OWNED ELECTRIC UTILITY PLANT

Under joint ownership agreements with other utilities, IPL and WPL have undivided ownership interests in jointly-owned EGUs. Each of the respective owners is responsible for the financing of its portion of the construction costs. IPL’s and WPL’s shares of expenses from jointly-owned EGUs are included in the corresponding operating expenses (e.g., electric production fuel, other operation and maintenance, etc.) in the income statements. Information relative to IPL’s and WPL’s ownership interest in these jointly-owned EGUs at December 31, 2021 was as follows (dollars in millions):

	Ownership	Electric	Accumulated Provision	Construction
	Interest %	Plant	for Depreciation	Work in Progress
IPL
Ottumwa Unit 1	48.0%	$599	$214	$11
George Neal Unit 4	25.7%	193	100	2
George Neal Unit 3	28.0%	173	74	3
Louisa Unit 1	4.0%	40	23	—
		1,005	411	16
WPL
Columbia Units 1-2	53.5%	802	314	6
West Riverside Energy Center and Solar Garden	91.0%	706	33	3
Forward Wind Energy Center	42.6%	118	48	—
		1,626	395	9
Alliant Energy		$2,631	$806	$25

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Receivables

12 Months Ended

Dec. 31, 2021

Accounts Receivable [Line Items]

Receivables

RECEIVABLES(a) Accounts Receivable - Details for accounts receivable included on the balance sheets as of December 31 were as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Customer	$93	$101	$—	$—	$82	$92
Unbilled utility revenues	91	82	—	—	91	82
Deferred proceeds	214	188	214	188	—	—
Other	53	59	28	23	25	35
Allowance for expected credit losses	(11)	(18)	(1)	(1)	(10)	(17)
	$440	$412	$241	$210	$188	$192

(b) Sales of Accounts Receivable - IPL maintains a Receivables Agreement whereby it may sell its customer accounts receivables, unbilled revenues and certain other accounts receivables to a third party through wholly-owned and consolidated special purpose entities. In April 2021, IPL amended and extended through March 2023 the purchase commitment from the third party to which it sells its receivables. IPL pays a monthly fee to the third party that varies based on interest rates, limits on cash proceeds and cash amounts received from the third party. Deferred proceeds represent IPL’s interest in the receivables sold to the third party. At IPL’s request, deferred proceeds are paid to IPL from collections of receivables, after paying any required expenses incurred by the third party and the collection agent. Corporate Services acts as collection agent for the third party and receives a fee for collection services. The Receivables Agreement can be terminated by the third party if arrears or write-offs exceed certain levels. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. IPL believes that the allowance for expected credit losses related to its sales of receivables is a reasonable approximation of credit risk of the customers that generated the receivables. Refer to Note 16 for discussion of the fair value of deferred proceeds.

Under the Receivables Agreement, IPL has the right to receive cash proceeds, up to a certain limit, from the third party in exchange for the receivables sold. Effective April 2021, the limit on cash proceeds is $110 million. Cash proceeds are used by IPL to meet short-term financing needs, and cannot exceed the current limit or amount of receivables available for sale, whichever is less. As of December 31, 2021, IPL had $109 million of available capacity under its sales of accounts receivable program. IPL’s maximum and average outstanding aggregate cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program were as follows (in millions):

	Maximum			Average
	2021	2020	2019	2021	2020	2019
Outstanding aggregate cash proceeds	$110	$96	$108	$46	$9	$36

As of December 31, the attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

	2021	2020
Customer accounts receivable	$125	$114
Unbilled utility revenues	104	92
Receivables sold to third party	229	206
Less: cash proceeds	1	1
Deferred proceeds	228	205
Less: allowance for expected credit losses	14	17
Fair value of deferred proceeds	$214	$188
Outstanding receivables past due	$22	$27

Additional attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

	2021	2020	2019
Collections	$2,134	$2,025	$2,193
Write-offs, net of recoveries	9	7	19

IPL [Member]

Accounts Receivable [Line Items]

Receivables

RECEIVABLES(a) Accounts Receivable - Details for accounts receivable included on the balance sheets as of December 31 were as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Customer	$93	$101	$—	$—	$82	$92
Unbilled utility revenues	91	82	—	—	91	82
Deferred proceeds	214	188	214	188	—	—
Other	53	59	28	23	25	35
Allowance for expected credit losses	(11)	(18)	(1)	(1)	(10)	(17)
	$440	$412	$241	$210	$188	$192

(b) Sales of Accounts Receivable - IPL maintains a Receivables Agreement whereby it may sell its customer accounts receivables, unbilled revenues and certain other accounts receivables to a third party through wholly-owned and consolidated special purpose entities. In April 2021, IPL amended and extended through March 2023 the purchase commitment from the third party to which it sells its receivables. IPL pays a monthly fee to the third party that varies based on interest rates, limits on cash proceeds and cash amounts received from the third party. Deferred proceeds represent IPL’s interest in the receivables sold to the third party. At IPL’s request, deferred proceeds are paid to IPL from collections of receivables, after paying any required expenses incurred by the third party and the collection agent. Corporate Services acts as collection agent for the third party and receives a fee for collection services. The Receivables Agreement can be terminated by the third party if arrears or write-offs exceed certain levels. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. IPL believes that the allowance for expected credit losses related to its sales of receivables is a reasonable approximation of credit risk of the customers that generated the receivables. Refer to Note 16 for discussion of the fair value of deferred proceeds.

Under the Receivables Agreement, IPL has the right to receive cash proceeds, up to a certain limit, from the third party in exchange for the receivables sold. Effective April 2021, the limit on cash proceeds is $110 million. Cash proceeds are used by IPL to meet short-term financing needs, and cannot exceed the current limit or amount of receivables available for sale, whichever is less. As of December 31, 2021, IPL had $109 million of available capacity under its sales of accounts receivable program. IPL’s maximum and average outstanding aggregate cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program were as follows (in millions):

	Maximum			Average
	2021	2020	2019	2021	2020	2019
Outstanding aggregate cash proceeds	$110	$96	$108	$46	$9	$36

As of December 31, the attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

	2021	2020
Customer accounts receivable	$125	$114
Unbilled utility revenues	104	92
Receivables sold to third party	229	206
Less: cash proceeds	1	1
Deferred proceeds	228	205
Less: allowance for expected credit losses	14	17
Fair value of deferred proceeds	$214	$188
Outstanding receivables past due	$22	$27

Additional attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

	2021	2020	2019
Collections	$2,134	$2,025	$2,193
Write-offs, net of recoveries	9	7	19

WPL [Member]

Accounts Receivable [Line Items]

Receivables

RECEIVABLES(a) Accounts Receivable - Details for accounts receivable included on the balance sheets as of December 31 were as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Customer	$93	$101	$—	$—	$82	$92
Unbilled utility revenues	91	82	—	—	91	82
Deferred proceeds	214	188	214	188	—	—
Other	53	59	28	23	25	35
Allowance for expected credit losses	(11)	(18)	(1)	(1)	(10)	(17)
	$440	$412	$241	$210	$188	$192

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Investments

12 Months Ended

Dec. 31, 2021

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, 2021	2021	2020	2021	2020	2019
ATC Holdings	16%, 20%	$338	$331	($43)	($47)	($45)
Non-utility wind farm in Oklahoma	50%	99	103	(4)	(8)	(5)
Corporate venture investments	Various	52	31	(13)	(4)	(1)
Other	Various	19	11	(2)	(2)	(2)
		$508	$476	($62)	($61)	($53)

Summary aggregate financial information from the financial statements of these holdings is as follows (in millions):

	Alliant Energy
	2021	2020	2019
Revenues	$802	$801	$783
Operating income	357	376	359
Net income	358	343	340
As of December 31:
Current assets	112	121
Non-current assets	7,036	6,388
Current liabilities	455	317
Non-current liabilities	3,110	2,997
Noncontrolling interest	247	192

ATC Holdings - As of December 31, 2021, 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.

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 coalition with different energy companies across the U.S., working together to help identify and research innovative products, technologies and business models within the emerging energy economy.

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Common Equity

12 Months Ended

Dec. 31, 2021

Schedule of Common Equity [Line Items]

Common Equity

COMMON EQUITY

Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows:

	2021	2020	2019
Shares outstanding, January 1	249,868,415	245,022,800	236,063,279
Equity forward agreements	—	4,275,127	8,358,973
Shareowner Direct Plan	492,565	472,283	501,808
Equity-based compensation plans	113,549	98,205	101,478
Other	—	—	(2,738)
Shares outstanding, December 31	250,474,529	249,868,415	245,022,800

At December 31, 2021, Alliant Energy had a total of 14 million shares available for issuance in the aggregate, pursuant to its 2020 OIP, Shareowner Direct Plan and 401(k) Savings Plan.

Equity Forward Agreements - In 2018, Alliant Energy entered into forward sale agreements with various counterparties in connection with a public offering of 8,358,973 shares of Alliant Energy common stock. In 2019, Alliant Energy settled $366 million under the forward sale agreements by delivering 8,358,973 shares of newly issued Alliant Energy common stock at a weighted average forward sale price of $43.75 per share. Alliant Energy used the net proceeds from the settlements for general corporate purposes.

In 2019, Alliant Energy entered into forward sale agreements with a counterparty in connection with a public offering of 4,275,127 shares of Alliant Energy common stock. In 2020, Alliant Energy settled $222 million under the forward sale agreements by delivering 4,275,127 shares of newly issued Alliant Energy common stock at a weighted average forward sale price of $51.98 per share. Alliant Energy used the net proceeds from the settlements for general corporate purposes.

Shareowner Direct Plan - Alliant Energy satisfies its requirements under the Shareowner Direct Plan (dividend reinvestment and stock purchase plan) by acquiring Alliant Energy common stock through original issue, rather than on the open market.

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Preferred Stock

12 Months Ended

Dec. 31, 2021

Preferred Stock

PREFERRED STOCK

IPL is authorized to issue up to 16,000,000 shares of cumulative preferred stock in aggregate. Information related to IPL’s cumulative preferred stock at December 31, 2020 was as follows (dollars in millions):

Series	Liquidation Preference/Stated Value	Shares Authorized	Shares Outstanding	Carrying Value
5.1%	$25	8,000,000	8,000,000	$200

In December 2021, IPL redeemed all 8,000,000 outstanding shares of its 5.1% cumulative preferred stock at the $25 per share par value for $200 million plus accrued and unpaid dividends up to the redemption date. In 2021, Alliant Energy and IPL recorded a $5 million non-cash charge related to this transaction in “Preferred dividend requirements” in their income statements.

IPL [Member]

Preferred Stock

PREFERRED STOCK

IPL is authorized to issue up to 16,000,000 shares of cumulative preferred stock in aggregate. Information related to IPL’s cumulative preferred stock at December 31, 2020 was as follows (dollars in millions):

Series	Liquidation Preference/Stated Value	Shares Authorized	Shares Outstanding	Carrying Value
5.1%	$25	8,000,000	8,000,000	$200

In December 2021, IPL redeemed all 8,000,000 outstanding shares of its 5.1% cumulative preferred stock at the $25 per share par value for $200 million plus accrued and unpaid dividends up to the redemption date. In 2021, Alliant Energy and IPL recorded a $5 million non-cash charge related to this transaction in “Preferred dividend requirements” in their income statements.

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Debt

12 Months Ended

Dec. 31, 2021

Debt Instrument [Line Items]

Debt

DEBT(a) Short-term Debt - Alliant Energy and its subsidiaries maintain committed bank lines of credit to provide short-term borrowing flexibility and back-stop liquidity for commercial paper outstanding. At December 31, 2021, the short-term borrowing capacity under a single credit facility agreement, which expires in December 2026, totaled $1 billion ($450 million for Alliant Energy at the parent company level, $250 million for IPL and $300 million for WPL). Subject to certain conditions, Alliant Energy (at the parent company level), IPL and WPL may each reallocate and change its sublimit up to $500 million, $400 million and $500 million, respectively, within the $1 billion total commitment. Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, classified as short-term debt was as follows (dollars in millions):

	Alliant Energy		IPL		WPL
December 31	2021	2020	2021	2020	2021	2020
Amount outstanding	$515	$389	$—	$—	$236	$257
Weighted average interest rates	0.2%	0.2%	N/A	N/A	0.2%	0.1%
Available credit facility capacity	$485	$611	$250	$250	$64	$43

	Alliant Energy		IPL		WPL
For the year ended	2021	2020	2021	2020	2021	2020
Maximum amount outstanding (based on daily outstanding balances)	$648	$495	$19	$8	$320	$266
Average amount outstanding (based on daily outstanding balances)	$459	$292	$—	$—	$172	$117
Weighted average interest rates	0.2%	0.7%	0.2%	0.5%	0.1%	0.7%

(b) Long-Term Debt - Long-term debt, net as of December 31 was as follows (dollars in millions):

	2021			2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Senior Debentures (a):
3.25%, due 2024	$500	$500	$—	$500	$500	$—
3.4%, due 2025	250	250	—	250	250	—
5.5%, due 2025	50	50	—	50	50	—
4.1%, due 2028	500	500	—	500	500	—
3.6%, due 2029	300	300	—	300	300	—
2.3%, due 2030	400	400	—	400	400	—
6.45%, due 2033	100	100	—	100	100	—
6.3%, due 2034	125	125	—	125	125	—
6.25%, due 2039	300	300	—	300	300	—
4.7%, due 2043	250	250	—	250	250	—
3.7%, due 2046	300	300	—	300	300	—
3.5%, due 2049	300	300	—	300	300	—
3.1%, due 2051 (b)	300	300	—	—	—	—
	3,675	3,675	—	3,375	3,375	—
Debentures (a):
2.25%, due 2022	250	—	250	250	—	250
3.05%, due 2027	300	—	300	300	—	300
3%, due 2029	350	—	350	350	—	350
1.95%, due 2031 (c)	300	—	300	—	—	—
6.25%, due 2034	100	—	100	100	—	100
6.375%, due 2037	300	—	300	300	—	300
7.6%, due 2038	250	—	250	250	—	250
4.1%, due 2044	250	—	250	250	—	250
3.65%, due 2050	350	—	350	350	—	350
	2,450	—	2,450	2,150	—	2,150
Other:
AEF term loan credit agreement through March 2022, 1% at December 31, 2021 (with Alliant Energy as guarantor)	300	—	—	300	—	—
Corporate Services 3.45% senior notes, due 2022 (a)	75	—	—	75	—	—
AEF 3.75% senior notes, due 2023 (with Alliant Energy as guarantor) (a)	400	—	—	400	—	—
AEF 1.4% senior notes, due 2026 (with Alliant Energy as guarantor) (a)	200	—	—	200	—	—
AEF 4.25% senior notes, due 2028 (with Alliant Energy as guarantor) (a)	300	—	—	300	—	—
Sheboygan Power, LLC 5.06% senior secured notes, due 2022 to 2024 (secured by the Sheboygan Falls Energy Facility and related assets) (a)	24	—	—	31	—	—
Other, 1% at December 31, 2021, due 2022 to 2025	1	—	—	2	—	—
	1,300	—	—	1,308	—	—
Subtotal	7,425	3,675	2,450	6,833	3,375	2,150
Current maturities	(633)	—	(250)	(8)	—	—
Unamortized debt issuance costs	(42)	(23)	(15)	(41)	(22)	(14)
Unamortized debt (discount) and premium, net	(15)	(9)	(6)	(15)	(8)	(6)
Long-term debt, net (d)	$6,735	$3,643	$2,179	$6,769	$3,345	$2,130

(a)Contains optional redemption provisions which, if elected by the issuer at its sole discretion, could require material redemption premium payments by the issuer. The redemption premium payments under these optional redemption provisions are variable and dependent on applicable U.S. Treasury rates at the time of redemption.

(b)In November 2021, IPL issued $300 million of 3.1% senior debentures due 2051. The net proceeds from the issuance were used by IPL to retire its cumulative preferred stock in 2021 and for general corporate purposes.

(c)In September 2021, WPL issued $300 million of 1.95% debentures due 2031. The debentures were issued as green bonds, and an amount in excess of the net proceeds was disbursed for the construction and development of WPL’s wind and solar EGUs.

(d)There were no significant sinking fund requirements related to the outstanding long-term debt.

Five-Year Schedule of Long-term Debt Maturities - At December 31, 2021, long-term debt maturities for 2022 through 2026 were as follows (in millions):

	2022	2023	2024	2025	2026
IPL	$—	$—	$500	$300	$—
WPL	250	—	—	—	—
Corporate Services	75	—	—	—	—
AEF	308	408	9	—	200
Alliant Energy	$633	$408	$509	$300	$200

Fair Value of Long-term Debt - Refer to Note 16 for information on the fair value of long-term debt outstanding.

IPL [Member]

Debt Instrument [Line Items]

Debt

DEBT(a) Short-term Debt - Alliant Energy and its subsidiaries maintain committed bank lines of credit to provide short-term borrowing flexibility and back-stop liquidity for commercial paper outstanding. At December 31, 2021, the short-term borrowing capacity under a single credit facility agreement, which expires in December 2026, totaled $1 billion ($450 million for Alliant Energy at the parent company level, $250 million for IPL and $300 million for WPL). Subject to certain conditions, Alliant Energy (at the parent company level), IPL and WPL may each reallocate and change its sublimit up to $500 million, $400 million and $500 million, respectively, within the $1 billion total commitment. Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, classified as short-term debt was as follows (dollars in millions):

	Alliant Energy		IPL		WPL
December 31	2021	2020	2021	2020	2021	2020
Amount outstanding	$515	$389	$—	$—	$236	$257
Weighted average interest rates	0.2%	0.2%	N/A	N/A	0.2%	0.1%
Available credit facility capacity	$485	$611	$250	$250	$64	$43

	Alliant Energy		IPL		WPL
For the year ended	2021	2020	2021	2020	2021	2020
Maximum amount outstanding (based on daily outstanding balances)	$648	$495	$19	$8	$320	$266
Average amount outstanding (based on daily outstanding balances)	$459	$292	$—	$—	$172	$117
Weighted average interest rates	0.2%	0.7%	0.2%	0.5%	0.1%	0.7%

(b) Long-Term Debt - Long-term debt, net as of December 31 was as follows (dollars in millions):

	2021			2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Senior Debentures (a):
3.25%, due 2024	$500	$500	$—	$500	$500	$—
3.4%, due 2025	250	250	—	250	250	—
5.5%, due 2025	50	50	—	50	50	—
4.1%, due 2028	500	500	—	500	500	—
3.6%, due 2029	300	300	—	300	300	—
2.3%, due 2030	400	400	—	400	400	—
6.45%, due 2033	100	100	—	100	100	—
6.3%, due 2034	125	125	—	125	125	—
6.25%, due 2039	300	300	—	300	300	—
4.7%, due 2043	250	250	—	250	250	—
3.7%, due 2046	300	300	—	300	300	—
3.5%, due 2049	300	300	—	300	300	—
3.1%, due 2051 (b)	300	300	—	—	—	—
	3,675	3,675	—	3,375	3,375	—
Debentures (a):
2.25%, due 2022	250	—	250	250	—	250
3.05%, due 2027	300	—	300	300	—	300
3%, due 2029	350	—	350	350	—	350
1.95%, due 2031 (c)	300	—	300	—	—	—
6.25%, due 2034	100	—	100	100	—	100
6.375%, due 2037	300	—	300	300	—	300
7.6%, due 2038	250	—	250	250	—	250
4.1%, due 2044	250	—	250	250	—	250
3.65%, due 2050	350	—	350	350	—	350
	2,450	—	2,450	2,150	—	2,150
Other:
AEF term loan credit agreement through March 2022, 1% at December 31, 2021 (with Alliant Energy as guarantor)	300	—	—	300	—	—
Corporate Services 3.45% senior notes, due 2022 (a)	75	—	—	75	—	—
AEF 3.75% senior notes, due 2023 (with Alliant Energy as guarantor) (a)	400	—	—	400	—	—
AEF 1.4% senior notes, due 2026 (with Alliant Energy as guarantor) (a)	200	—	—	200	—	—
AEF 4.25% senior notes, due 2028 (with Alliant Energy as guarantor) (a)	300	—	—	300	—	—
Sheboygan Power, LLC 5.06% senior secured notes, due 2022 to 2024 (secured by the Sheboygan Falls Energy Facility and related assets) (a)	24	—	—	31	—	—
Other, 1% at December 31, 2021, due 2022 to 2025	1	—	—	2	—	—
	1,300	—	—	1,308	—	—
Subtotal	7,425	3,675	2,450	6,833	3,375	2,150
Current maturities	(633)	—	(250)	(8)	—	—
Unamortized debt issuance costs	(42)	(23)	(15)	(41)	(22)	(14)
Unamortized debt (discount) and premium, net	(15)	(9)	(6)	(15)	(8)	(6)
Long-term debt, net (d)	$6,735	$3,643	$2,179	$6,769	$3,345	$2,130

(a)Contains optional redemption provisions which, if elected by the issuer at its sole discretion, could require material redemption premium payments by the issuer. The redemption premium payments under these optional redemption provisions are variable and dependent on applicable U.S. Treasury rates at the time of redemption.

(b)In November 2021, IPL issued $300 million of 3.1% senior debentures due 2051. The net proceeds from the issuance were used by IPL to retire its cumulative preferred stock in 2021 and for general corporate purposes.

(c)In September 2021, WPL issued $300 million of 1.95% debentures due 2031. The debentures were issued as green bonds, and an amount in excess of the net proceeds was disbursed for the construction and development of WPL’s wind and solar EGUs.

(d)There were no significant sinking fund requirements related to the outstanding long-term debt.

Five-Year Schedule of Long-term Debt Maturities - At December 31, 2021, long-term debt maturities for 2022 through 2026 were as follows (in millions):

	2022	2023	2024	2025	2026
IPL	$—	$—	$500	$300	$—
WPL	250	—	—	—	—
Corporate Services	75	—	—	—	—
AEF	308	408	9	—	200
Alliant Energy	$633	$408	$509	$300	$200

Fair Value of Long-term Debt - Refer to Note 16 for information on the fair value of long-term debt outstanding.

WPL [Member]

Debt Instrument [Line Items]

Debt

DEBT(a) Short-term Debt - Alliant Energy and its subsidiaries maintain committed bank lines of credit to provide short-term borrowing flexibility and back-stop liquidity for commercial paper outstanding. At December 31, 2021, the short-term borrowing capacity under a single credit facility agreement, which expires in December 2026, totaled $1 billion ($450 million for Alliant Energy at the parent company level, $250 million for IPL and $300 million for WPL). Subject to certain conditions, Alliant Energy (at the parent company level), IPL and WPL may each reallocate and change its sublimit up to $500 million, $400 million and $500 million, respectively, within the $1 billion total commitment. Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, classified as short-term debt was as follows (dollars in millions):

	Alliant Energy		IPL		WPL
December 31	2021	2020	2021	2020	2021	2020
Amount outstanding	$515	$389	$—	$—	$236	$257
Weighted average interest rates	0.2%	0.2%	N/A	N/A	0.2%	0.1%
Available credit facility capacity	$485	$611	$250	$250	$64	$43

	Alliant Energy		IPL		WPL
For the year ended	2021	2020	2021	2020	2021	2020
Maximum amount outstanding (based on daily outstanding balances)	$648	$495	$19	$8	$320	$266
Average amount outstanding (based on daily outstanding balances)	$459	$292	$—	$—	$172	$117
Weighted average interest rates	0.2%	0.7%	0.2%	0.5%	0.1%	0.7%

(b) Long-Term Debt - Long-term debt, net as of December 31 was as follows (dollars in millions):

	2021			2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Senior Debentures (a):
3.25%, due 2024	$500	$500	$—	$500	$500	$—
3.4%, due 2025	250	250	—	250	250	—
5.5%, due 2025	50	50	—	50	50	—
4.1%, due 2028	500	500	—	500	500	—
3.6%, due 2029	300	300	—	300	300	—
2.3%, due 2030	400	400	—	400	400	—
6.45%, due 2033	100	100	—	100	100	—
6.3%, due 2034	125	125	—	125	125	—
6.25%, due 2039	300	300	—	300	300	—
4.7%, due 2043	250	250	—	250	250	—
3.7%, due 2046	300	300	—	300	300	—
3.5%, due 2049	300	300	—	300	300	—
3.1%, due 2051 (b)	300	300	—	—	—	—
	3,675	3,675	—	3,375	3,375	—
Debentures (a):
2.25%, due 2022	250	—	250	250	—	250
3.05%, due 2027	300	—	300	300	—	300
3%, due 2029	350	—	350	350	—	350
1.95%, due 2031 (c)	300	—	300	—	—	—
6.25%, due 2034	100	—	100	100	—	100
6.375%, due 2037	300	—	300	300	—	300
7.6%, due 2038	250	—	250	250	—	250
4.1%, due 2044	250	—	250	250	—	250
3.65%, due 2050	350	—	350	350	—	350
	2,450	—	2,450	2,150	—	2,150
Other:
AEF term loan credit agreement through March 2022, 1% at December 31, 2021 (with Alliant Energy as guarantor)	300	—	—	300	—	—
Corporate Services 3.45% senior notes, due 2022 (a)	75	—	—	75	—	—
AEF 3.75% senior notes, due 2023 (with Alliant Energy as guarantor) (a)	400	—	—	400	—	—
AEF 1.4% senior notes, due 2026 (with Alliant Energy as guarantor) (a)	200	—	—	200	—	—
AEF 4.25% senior notes, due 2028 (with Alliant Energy as guarantor) (a)	300	—	—	300	—	—
Sheboygan Power, LLC 5.06% senior secured notes, due 2022 to 2024 (secured by the Sheboygan Falls Energy Facility and related assets) (a)	24	—	—	31	—	—
Other, 1% at December 31, 2021, due 2022 to 2025	1	—	—	2	—	—
	1,300	—	—	1,308	—	—
Subtotal	7,425	3,675	2,450	6,833	3,375	2,150
Current maturities	(633)	—	(250)	(8)	—	—
Unamortized debt issuance costs	(42)	(23)	(15)	(41)	(22)	(14)
Unamortized debt (discount) and premium, net	(15)	(9)	(6)	(15)	(8)	(6)
Long-term debt, net (d)	$6,735	$3,643	$2,179	$6,769	$3,345	$2,130

(a)Contains optional redemption provisions which, if elected by the issuer at its sole discretion, could require material redemption premium payments by the issuer. The redemption premium payments under these optional redemption provisions are variable and dependent on applicable U.S. Treasury rates at the time of redemption.

(b)In November 2021, IPL issued $300 million of 3.1% senior debentures due 2051. The net proceeds from the issuance were used by IPL to retire its cumulative preferred stock in 2021 and for general corporate purposes.

(c)In September 2021, WPL issued $300 million of 1.95% debentures due 2031. The debentures were issued as green bonds, and an amount in excess of the net proceeds was disbursed for the construction and development of WPL’s wind and solar EGUs.

(d)There were no significant sinking fund requirements related to the outstanding long-term debt.

Five-Year Schedule of Long-term Debt Maturities - At December 31, 2021, long-term debt maturities for 2022 through 2026 were as follows (in millions):

	2022	2023	2024	2025	2026
IPL	$—	$—	$500	$300	$—
WPL	250	—	—	—	—
Corporate Services	75	—	—	—	—
AEF	308	408	9	—	200
Alliant Energy	$633	$408	$509	$300	$200

Fair Value of Long-term Debt - Refer to Note 16 for information on the fair value of long-term debt outstanding.

XML

Leases

12 Months Ended

Dec. 31, 2021

Leases [Line Items]

Operating Leases

LEASES

Operating Leases - Alliant Energy’s, IPL’s and WPL’s operating leases primarily include leases of space on telecommunication towers and leases of property. Operating lease details are as follows (dollars in millions):

	December 31, 2021			December 31, 2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Property, plant and equipment, net	$14	$9	$5	$15	$9	$6
Other current liabilities	$2	$1	$1	$2	$1	$1
Other liabilities	12	8	4	13	8	5
Total operating lease liabilities	$14	$9	$5	$15	$9	$6
Weighted average remaining lease term	9 years	11 years	8 years	10 years	11 years	9 years
Weighted average discount rate	4%	4%	4%	4%	4%	4%

Finance Leases - WPL is currently leasing the Sheboygan Falls Energy Facility from AEF’s Non-utility Generation business through 2025, the initial lease term. WPL is responsible for the operation of the EGU and has exclusive rights to its output. This finance lease contains two lease renewal periods, which are not included in the finance lease obligation, as well as an option to purchase the facility at the end of the initial lease term. For Alliant Energy, the leased Sheboygan Falls Energy Facility is eliminated upon consolidation and is therefore is not reflected in Alliant Energy’s amounts below.

Related to its investments in solar generation, WPL entered into land lease agreements with unaffiliated parties that commenced in 2021. The leases have various terms with optional renewal periods that are assumed to be extended through the end of the estimated useful lives of the solar generating facilities. The leases do not contain purchase options and are fixed lease payments.

Finance lease details are as follows (dollars in millions):

	Alliant Energy	WPL
	December 31, 2021	December 31, 2021	December 31, 2020
Property, plant and equipment, net:
Sheboygan Falls Energy Facility	n/a	$21	$27
Leased land for solar generation	$11	11	—
	$11	$32	$27
Other current liabilities:
Sheboygan Falls Energy Facility	n/a	$10	$9
Leased land for solar generation	$1	1	—
	1	11	9
Other liabilities:
Sheboygan Falls Energy Facility	n/a	31	42
Leased land for solar generation	11	11	—
	11	42	42
Total finance lease liabilities	$12	$53	$51
Weighted average remaining lease term	34 years	10 years	4 years
Weighted average discount rate	3%	9%	11%
	2021	2021	2020	2019
Depreciation and amortization expenses	$—	$6	$6	$6
Interest expense	—	5	6	7
Total finance lease expense	$—	$11	$12	$13

Expected Maturities - As of December 31, 2021, expected maturities of lease liabilities were as follows (in millions):

	2022	2023	2024	2025	2026	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$2	$2	$2	$2	$2	$7	$17	$3	$14
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	1	6	1	5
Finance Leases:
Alliant Energy	—	—	—	—	1	19	20	8	12
WPL	15	15	15	6	1	19	71	18	53

Finance Leases

LEASES

Operating Leases - Alliant Energy’s, IPL’s and WPL’s operating leases primarily include leases of space on telecommunication towers and leases of property. Operating lease details are as follows (dollars in millions):

	December 31, 2021			December 31, 2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Property, plant and equipment, net	$14	$9	$5	$15	$9	$6
Other current liabilities	$2	$1	$1	$2	$1	$1
Other liabilities	12	8	4	13	8	5
Total operating lease liabilities	$14	$9	$5	$15	$9	$6
Weighted average remaining lease term	9 years	11 years	8 years	10 years	11 years	9 years
Weighted average discount rate	4%	4%	4%	4%	4%	4%

Finance Leases - WPL is currently leasing the Sheboygan Falls Energy Facility from AEF’s Non-utility Generation business through 2025, the initial lease term. WPL is responsible for the operation of the EGU and has exclusive rights to its output. This finance lease contains two lease renewal periods, which are not included in the finance lease obligation, as well as an option to purchase the facility at the end of the initial lease term. For Alliant Energy, the leased Sheboygan Falls Energy Facility is eliminated upon consolidation and is therefore is not reflected in Alliant Energy’s amounts below.

Related to its investments in solar generation, WPL entered into land lease agreements with unaffiliated parties that commenced in 2021. The leases have various terms with optional renewal periods that are assumed to be extended through the end of the estimated useful lives of the solar generating facilities. The leases do not contain purchase options and are fixed lease payments.

Finance lease details are as follows (dollars in millions):

	Alliant Energy	WPL
	December 31, 2021	December 31, 2021	December 31, 2020
Property, plant and equipment, net:
Sheboygan Falls Energy Facility	n/a	$21	$27
Leased land for solar generation	$11	11	—
	$11	$32	$27
Other current liabilities:
Sheboygan Falls Energy Facility	n/a	$10	$9
Leased land for solar generation	$1	1	—
	1	11	9
Other liabilities:
Sheboygan Falls Energy Facility	n/a	31	42
Leased land for solar generation	11	11	—
	11	42	42
Total finance lease liabilities	$12	$53	$51
Weighted average remaining lease term	34 years	10 years	4 years
Weighted average discount rate	3%	9%	11%
	2021	2021	2020	2019
Depreciation and amortization expenses	$—	$6	$6	$6
Interest expense	—	5	6	7
Total finance lease expense	$—	$11	$12	$13

Expected Maturities - As of December 31, 2021, expected maturities of lease liabilities were as follows (in millions):

	2022	2023	2024	2025	2026	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$2	$2	$2	$2	$2	$7	$17	$3	$14
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	1	6	1	5
Finance Leases:
Alliant Energy	—	—	—	—	1	19	20	8	12
WPL	15	15	15	6	1	19	71	18	53

IPL [Member]

Leases [Line Items]

Operating Leases

LEASES

Operating Leases - Alliant Energy’s, IPL’s and WPL’s operating leases primarily include leases of space on telecommunication towers and leases of property. Operating lease details are as follows (dollars in millions):

	December 31, 2021			December 31, 2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Property, plant and equipment, net	$14	$9	$5	$15	$9	$6
Other current liabilities	$2	$1	$1	$2	$1	$1
Other liabilities	12	8	4	13	8	5
Total operating lease liabilities	$14	$9	$5	$15	$9	$6
Weighted average remaining lease term	9 years	11 years	8 years	10 years	11 years	9 years
Weighted average discount rate	4%	4%	4%	4%	4%	4%

Finance Leases - WPL is currently leasing the Sheboygan Falls Energy Facility from AEF’s Non-utility Generation business through 2025, the initial lease term. WPL is responsible for the operation of the EGU and has exclusive rights to its output. This finance lease contains two lease renewal periods, which are not included in the finance lease obligation, as well as an option to purchase the facility at the end of the initial lease term. For Alliant Energy, the leased Sheboygan Falls Energy Facility is eliminated upon consolidation and is therefore is not reflected in Alliant Energy’s amounts below.

Related to its investments in solar generation, WPL entered into land lease agreements with unaffiliated parties that commenced in 2021. The leases have various terms with optional renewal periods that are assumed to be extended through the end of the estimated useful lives of the solar generating facilities. The leases do not contain purchase options and are fixed lease payments.

Finance lease details are as follows (dollars in millions):

	Alliant Energy	WPL
	December 31, 2021	December 31, 2021	December 31, 2020
Property, plant and equipment, net:
Sheboygan Falls Energy Facility	n/a	$21	$27
Leased land for solar generation	$11	11	—
	$11	$32	$27
Other current liabilities:
Sheboygan Falls Energy Facility	n/a	$10	$9
Leased land for solar generation	$1	1	—
	1	11	9
Other liabilities:
Sheboygan Falls Energy Facility	n/a	31	42
Leased land for solar generation	11	11	—
	11	42	42
Total finance lease liabilities	$12	$53	$51
Weighted average remaining lease term	34 years	10 years	4 years
Weighted average discount rate	3%	9%	11%
	2021	2021	2020	2019
Depreciation and amortization expenses	$—	$6	$6	$6
Interest expense	—	5	6	7
Total finance lease expense	$—	$11	$12	$13

Expected Maturities - As of December 31, 2021, expected maturities of lease liabilities were as follows (in millions):

	2022	2023	2024	2025	2026	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$2	$2	$2	$2	$2	$7	$17	$3	$14
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	1	6	1	5
Finance Leases:
Alliant Energy	—	—	—	—	1	19	20	8	12
WPL	15	15	15	6	1	19	71	18	53

WPL [Member]

Leases [Line Items]

Operating Leases

LEASES

Operating Leases - Alliant Energy’s, IPL’s and WPL’s operating leases primarily include leases of space on telecommunication towers and leases of property. Operating lease details are as follows (dollars in millions):

	December 31, 2021			December 31, 2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Property, plant and equipment, net	$14	$9	$5	$15	$9	$6
Other current liabilities	$2	$1	$1	$2	$1	$1
Other liabilities	12	8	4	13	8	5
Total operating lease liabilities	$14	$9	$5	$15	$9	$6
Weighted average remaining lease term	9 years	11 years	8 years	10 years	11 years	9 years
Weighted average discount rate	4%	4%	4%	4%	4%	4%

Finance Leases - WPL is currently leasing the Sheboygan Falls Energy Facility from AEF’s Non-utility Generation business through 2025, the initial lease term. WPL is responsible for the operation of the EGU and has exclusive rights to its output. This finance lease contains two lease renewal periods, which are not included in the finance lease obligation, as well as an option to purchase the facility at the end of the initial lease term. For Alliant Energy, the leased Sheboygan Falls Energy Facility is eliminated upon consolidation and is therefore is not reflected in Alliant Energy’s amounts below.

Related to its investments in solar generation, WPL entered into land lease agreements with unaffiliated parties that commenced in 2021. The leases have various terms with optional renewal periods that are assumed to be extended through the end of the estimated useful lives of the solar generating facilities. The leases do not contain purchase options and are fixed lease payments.

Finance lease details are as follows (dollars in millions):

	Alliant Energy	WPL
	December 31, 2021	December 31, 2021	December 31, 2020
Property, plant and equipment, net:
Sheboygan Falls Energy Facility	n/a	$21	$27
Leased land for solar generation	$11	11	—
	$11	$32	$27
Other current liabilities:
Sheboygan Falls Energy Facility	n/a	$10	$9
Leased land for solar generation	$1	1	—
	1	11	9
Other liabilities:
Sheboygan Falls Energy Facility	n/a	31	42
Leased land for solar generation	11	11	—
	11	42	42
Total finance lease liabilities	$12	$53	$51
Weighted average remaining lease term	34 years	10 years	4 years
Weighted average discount rate	3%	9%	11%
	2021	2021	2020	2019
Depreciation and amortization expenses	$—	$6	$6	$6
Interest expense	—	5	6	7
Total finance lease expense	$—	$11	$12	$13

Expected Maturities - As of December 31, 2021, expected maturities of lease liabilities were as follows (in millions):

	2022	2023	2024	2025	2026	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$2	$2	$2	$2	$2	$7	$17	$3	$14
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	1	6	1	5
Finance Leases:
Alliant Energy	—	—	—	—	1	19	20	8	12
WPL	15	15	15	6	1	19	71	18	53

Finance Leases

LEASES

Operating Leases - Alliant Energy’s, IPL’s and WPL’s operating leases primarily include leases of space on telecommunication towers and leases of property. Operating lease details are as follows (dollars in millions):

	December 31, 2021			December 31, 2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Property, plant and equipment, net	$14	$9	$5	$15	$9	$6
Other current liabilities	$2	$1	$1	$2	$1	$1
Other liabilities	12	8	4	13	8	5
Total operating lease liabilities	$14	$9	$5	$15	$9	$6
Weighted average remaining lease term	9 years	11 years	8 years	10 years	11 years	9 years
Weighted average discount rate	4%	4%	4%	4%	4%	4%

Finance Leases - WPL is currently leasing the Sheboygan Falls Energy Facility from AEF’s Non-utility Generation business through 2025, the initial lease term. WPL is responsible for the operation of the EGU and has exclusive rights to its output. This finance lease contains two lease renewal periods, which are not included in the finance lease obligation, as well as an option to purchase the facility at the end of the initial lease term. For Alliant Energy, the leased Sheboygan Falls Energy Facility is eliminated upon consolidation and is therefore is not reflected in Alliant Energy’s amounts below.

Related to its investments in solar generation, WPL entered into land lease agreements with unaffiliated parties that commenced in 2021. The leases have various terms with optional renewal periods that are assumed to be extended through the end of the estimated useful lives of the solar generating facilities. The leases do not contain purchase options and are fixed lease payments.

Finance lease details are as follows (dollars in millions):

	Alliant Energy	WPL
	December 31, 2021	December 31, 2021	December 31, 2020
Property, plant and equipment, net:
Sheboygan Falls Energy Facility	n/a	$21	$27
Leased land for solar generation	$11	11	—
	$11	$32	$27
Other current liabilities:
Sheboygan Falls Energy Facility	n/a	$10	$9
Leased land for solar generation	$1	1	—
	1	11	9
Other liabilities:
Sheboygan Falls Energy Facility	n/a	31	42
Leased land for solar generation	11	11	—
	11	42	42
Total finance lease liabilities	$12	$53	$51
Weighted average remaining lease term	34 years	10 years	4 years
Weighted average discount rate	3%	9%	11%
	2021	2021	2020	2019
Depreciation and amortization expenses	$—	$6	$6	$6
Interest expense	—	5	6	7
Total finance lease expense	$—	$11	$12	$13

Expected Maturities - As of December 31, 2021, expected maturities of lease liabilities were as follows (in millions):

	2022	2023	2024	2025	2026	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$2	$2	$2	$2	$2	$7	$17	$3	$14
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	1	6	1	5
Finance Leases:
Alliant Energy	—	—	—	—	1	19	20	8	12
WPL	15	15	15	6	1	19	71	18	53

XML

Revenues

12 Months Ended

Dec. 31, 2021

Disaggregation of Revenue [Line Items]

Revenues

REVENUES

Revenues from Alliant Energy’s, IPL’s and WPL’s utility businesses are primarily from electric and gas sales provided to customers based on approved tariffs or specific contracts with customers. IPL’s and WPL’s primary performance obligations under such arrangements are to deliver electricity and gas, and their customers simultaneously receive and consume the electricity and gas. For such arrangements, revenues are recognized equivalent to the value of the electricity or gas supplied during each period, including amounts billed during each period and changes in amounts estimated to be billed at the end of each period. IPL and WPL apply the right to invoice method to measure progress towards completing performance obligations to transfer electricity and gas to their customers.

IPL provides retail electric and gas service to customers in Iowa, and WPL provides retail and wholesale electric and retail gas service to customers in Wisconsin. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa, as well as steam from its Prairie Creek Generating Station to high-pressure steam customers in Iowa.

IPL’s and WPL’s retail electric and gas revenues include sales to residential, commercial and industrial customers. IPL’s and WPL’s retail electric and gas customer prices are based on IPL’s and WPL’s cost of service and are determined through general rate review proceedings and various tariff filings with the IUB and PSCW, respectively. Such tariff-based services provide electricity or gas to customers without a defined contractual term.

IPL and WPL have wholesale electric market-based rate authority from FERC allowing them to participate in wholesale energy markets (e.g. MISO) and transact directly with third parties. This authority from FERC allows sales of electricity referred to as bulk power sales based on current market values. FERC also allows IPL and WPL to enter into power supply agreements with municipalities and rural electric cooperatives with defined contractual terms, which include standard pricing mechanisms that are detailed in current tariffs accepted by FERC through wholesale rate review proceedings.

Revenues from Alliant Energy’s non-utility business customers are primarily from its Travero business, which includes a short-line rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; freight brokerage services; and a rail-served warehouse in Iowa, which began operations in 2021.

Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Electric Utility:
Retail - residential	$1,115	$1,093	$1,092	$620	$602	$601	$495	$491	$491
Retail - commercial	763	718	770	508	474	510	255	244	260
Retail - industrial	893	841	889	505	488	504	388	353	385
Wholesale	187	168	177	57	57	64	130	111	113
Bulk power and other	123	100	136	62	74	102	61	26	34
Total Electric Utility	3,081	2,920	3,064	1,752	1,695	1,781	1,329	1,225	1,283
Gas Utility:
Retail - residential	257	214	259	146	116	149	111	98	110
Retail - commercial	139	107	133	79	59	75	60	48	58
Retail - industrial	17	12	16	12	8	12	5	4	4
Transportation/other	43	40	47	28	25	28	15	15	19
Total Gas Utility	456	373	455	265	208	264	191	165	191
Other Utility:
Steam	36	36	37	36	36	37	—	—	—
Other utility	13	13	9	10	8	7	3	5	2
Total Other Utility	49	49	46	46	44	44	3	5	2
Non-Utility and Other:
Travero and other	83	74	83	—	—	—	—	—	—
Total Non-Utility and Other	83	74	83	—	—	—	—	—	—
Total revenues	$3,669	$3,416	$3,648	$2,063	$1,947	$2,089	$1,523	$1,395	$1,476

IPL [Member]

Disaggregation of Revenue [Line Items]

Revenues

REVENUES

Revenues from Alliant Energy’s, IPL’s and WPL’s utility businesses are primarily from electric and gas sales provided to customers based on approved tariffs or specific contracts with customers. IPL’s and WPL’s primary performance obligations under such arrangements are to deliver electricity and gas, and their customers simultaneously receive and consume the electricity and gas. For such arrangements, revenues are recognized equivalent to the value of the electricity or gas supplied during each period, including amounts billed during each period and changes in amounts estimated to be billed at the end of each period. IPL and WPL apply the right to invoice method to measure progress towards completing performance obligations to transfer electricity and gas to their customers.

IPL provides retail electric and gas service to customers in Iowa, and WPL provides retail and wholesale electric and retail gas service to customers in Wisconsin. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa, as well as steam from its Prairie Creek Generating Station to high-pressure steam customers in Iowa.

IPL’s and WPL’s retail electric and gas revenues include sales to residential, commercial and industrial customers. IPL’s and WPL’s retail electric and gas customer prices are based on IPL’s and WPL’s cost of service and are determined through general rate review proceedings and various tariff filings with the IUB and PSCW, respectively. Such tariff-based services provide electricity or gas to customers without a defined contractual term.

IPL and WPL have wholesale electric market-based rate authority from FERC allowing them to participate in wholesale energy markets (e.g. MISO) and transact directly with third parties. This authority from FERC allows sales of electricity referred to as bulk power sales based on current market values. FERC also allows IPL and WPL to enter into power supply agreements with municipalities and rural electric cooperatives with defined contractual terms, which include standard pricing mechanisms that are detailed in current tariffs accepted by FERC through wholesale rate review proceedings.

Revenues from Alliant Energy’s non-utility business customers are primarily from its Travero business, which includes a short-line rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; freight brokerage services; and a rail-served warehouse in Iowa, which began operations in 2021.

Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Electric Utility:
Retail - residential	$1,115	$1,093	$1,092	$620	$602	$601	$495	$491	$491
Retail - commercial	763	718	770	508	474	510	255	244	260
Retail - industrial	893	841	889	505	488	504	388	353	385
Wholesale	187	168	177	57	57	64	130	111	113
Bulk power and other	123	100	136	62	74	102	61	26	34
Total Electric Utility	3,081	2,920	3,064	1,752	1,695	1,781	1,329	1,225	1,283
Gas Utility:
Retail - residential	257	214	259	146	116	149	111	98	110
Retail - commercial	139	107	133	79	59	75	60	48	58
Retail - industrial	17	12	16	12	8	12	5	4	4
Transportation/other	43	40	47	28	25	28	15	15	19
Total Gas Utility	456	373	455	265	208	264	191	165	191
Other Utility:
Steam	36	36	37	36	36	37	—	—	—
Other utility	13	13	9	10	8	7	3	5	2
Total Other Utility	49	49	46	46	44	44	3	5	2
Non-Utility and Other:
Travero and other	83	74	83	—	—	—	—	—	—
Total Non-Utility and Other	83	74	83	—	—	—	—	—	—
Total revenues	$3,669	$3,416	$3,648	$2,063	$1,947	$2,089	$1,523	$1,395	$1,476

WPL [Member]

Disaggregation of Revenue [Line Items]

Revenues

REVENUES

Revenues from Alliant Energy’s, IPL’s and WPL’s utility businesses are primarily from electric and gas sales provided to customers based on approved tariffs or specific contracts with customers. IPL’s and WPL’s primary performance obligations under such arrangements are to deliver electricity and gas, and their customers simultaneously receive and consume the electricity and gas. For such arrangements, revenues are recognized equivalent to the value of the electricity or gas supplied during each period, including amounts billed during each period and changes in amounts estimated to be billed at the end of each period. IPL and WPL apply the right to invoice method to measure progress towards completing performance obligations to transfer electricity and gas to their customers.

IPL provides retail electric and gas service to customers in Iowa, and WPL provides retail and wholesale electric and retail gas service to customers in Wisconsin. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa, as well as steam from its Prairie Creek Generating Station to high-pressure steam customers in Iowa.

IPL’s and WPL’s retail electric and gas revenues include sales to residential, commercial and industrial customers. IPL’s and WPL’s retail electric and gas customer prices are based on IPL’s and WPL’s cost of service and are determined through general rate review proceedings and various tariff filings with the IUB and PSCW, respectively. Such tariff-based services provide electricity or gas to customers without a defined contractual term.

IPL and WPL have wholesale electric market-based rate authority from FERC allowing them to participate in wholesale energy markets (e.g. MISO) and transact directly with third parties. This authority from FERC allows sales of electricity referred to as bulk power sales based on current market values. FERC also allows IPL and WPL to enter into power supply agreements with municipalities and rural electric cooperatives with defined contractual terms, which include standard pricing mechanisms that are detailed in current tariffs accepted by FERC through wholesale rate review proceedings.

Revenues from Alliant Energy’s non-utility business customers are primarily from its Travero business, which includes a short-line rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; freight brokerage services; and a rail-served warehouse in Iowa, which began operations in 2021.

Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Electric Utility:
Retail - residential	$1,115	$1,093	$1,092	$620	$602	$601	$495	$491	$491
Retail - commercial	763	718	770	508	474	510	255	244	260
Retail - industrial	893	841	889	505	488	504	388	353	385
Wholesale	187	168	177	57	57	64	130	111	113
Bulk power and other	123	100	136	62	74	102	61	26	34
Total Electric Utility	3,081	2,920	3,064	1,752	1,695	1,781	1,329	1,225	1,283
Gas Utility:
Retail - residential	257	214	259	146	116	149	111	98	110
Retail - commercial	139	107	133	79	59	75	60	48	58
Retail - industrial	17	12	16	12	8	12	5	4	4
Transportation/other	43	40	47	28	25	28	15	15	19
Total Gas Utility	456	373	455	265	208	264	191	165	191
Other Utility:
Steam	36	36	37	36	36	37	—	—	—
Other utility	13	13	9	10	8	7	3	5	2
Total Other Utility	49	49	46	46	44	44	3	5	2
Non-Utility and Other:
Travero and other	83	74	83	—	—	—	—	—	—
Total Non-Utility and Other	83	74	83	—	—	—	—	—	—
Total revenues	$3,669	$3,416	$3,648	$2,063	$1,947	$2,089	$1,523	$1,395	$1,476

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Income Taxes

12 Months Ended

Dec. 31, 2021

Income Tax [Line Items]

Income Taxes

INCOME TAXES

Income Tax Expense (Benefit) - The components of “Income tax expense (benefit)” in the income statements were as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Current tax expense (benefit):
Federal	$1	$1	($7)	($21)	$6	($11)	$22	($11)	$12
State	3	8	24	(1)	(1)	24	6	7	13
IPL’s tax benefit riders	—	—	(4)	—	—	(4)	—	—	—
Deferred tax expense (benefit):
Federal	9	22	70	73	30	26	(75)	(9)	31
State	15	8	42	—	(2)	31	11	10	6
Production tax credits	(101)	(95)	(55)	(87)	(80)	(42)	(14)	(15)	(13)
Investment tax credits	(1)	(1)	(1)	—	—	—	(1)	(1)	—
	($74)	($57)	$69	($36)	($47)	$24	($51)	($19)	$49

Income Tax Rates - The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	Alliant Energy						IPL						WPL
	2021		2020		2019		2021		2020		2019		2021		2020		2019
Statutory federal income tax rate	21	%	21	%	21	%	21	%	21	%	21	%	21	%	21	%	21	%
State income taxes, net of federal benefits	2		2		7		(1)		(1)		8		6		6		6
Amortization of excess deferred taxes (Refer to Note 2)	(18)		(13)		(1)		(4)		(5)		—		(43)		(26)		(2)
Production tax credits	(17)		(17)		(9)		(27)		(28)		(13)		(6)		(7)		(5)
Effect of rate-making on property-related differences	(1)		(3)		(6)		(2)		(4)		(10)		(1)		(2)		(3)
Adjustment for prior period taxes	1		1		1		2		1		3		—		—		—
IPL’s tax benefit riders	—		—		(1)		—		—		(1)		—		—		—
Other items, net	—		(1)		(1)		—		—		—		(1)		—		—
Overall income tax rate	(12	%)	(10	%)	11	%	(11	%)	(16	%)	8	%	(24	%)	(8	%)	17	%

Deferred Tax Assets and Liabilities - The deferred tax assets and liabilities included on the balance sheets at December 31 arise from the following temporary differences (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Deferred tax liabilities:
Property	$2,389	$2,232	$1,416	$1,312	$913	$854
ATC Holdings	123	116	—	—	—	—
Other	111	101	76	83	50	41
Total deferred tax liabilities	2,623	2,449	1,492	1,395	963	895
Deferred tax assets:
Federal credit carryforwards	560	454	345	258	192	175
Net operating losses carryforwards - federal	39	77	36	71	—	1
Net operating losses carryforwards - state	38	37	3	1	—	—
Other	65	73	25	30	18	18
Subtotal deferred tax assets	702	641	409	360	210	194
Valuation allowances	(6)	(6)	—	—	—	(1)
Total deferred tax assets	696	635	409	360	210	193
Total deferred tax liabilities, net	$1,927	$1,814	$1,083	$1,035	$753	$702

Carryforwards - At December 31, 2021, carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy	IPL	WPL
Federal net operating losses	2037	$186	$172	$1
State net operating losses	2022-2041	619	28	2
Federal tax credits	2022-2041	560	345	192

Valuation Allowances - Alliant Energy currently expects its federal net operating losses carryforwards will not be fully utilized until 2023. Because taxable income must be reduced by federal net operating losses carryforwards prior to utilizing federal tax credit carryforwards, Alliant Energy currently does not expect to utilize 2002 vintage federal credit carryforwards prior to their expiration in 2022, resulting in valuation allowances as of December 31, 2021.

Uncertain Tax Positions - At December 31, 2021, 2020 and 2019, there were no uncertain tax positions or penalties accrued related to uncertain tax positions. As of December 31, 2021, no material changes to unrecognized tax benefits are expected during the next 12 months.

Open tax years - Tax years that remain subject to the statute of limitations in the major jurisdictions for each of Alliant Energy, IPL and WPL are as follows:

Consolidated federal income tax returns (a)	2018	-	2020
Consolidated Iowa income tax returns (b)	2018	-	2020
Wisconsin combined tax returns (c)	2017	-	2020

(a)The 2018 and 2019 federal tax returns are effectively settled as a result of participation in the IRS Compliance Assurance Program, which allows Alliant Energy and the IRS to work together to resolve issues related to Alliant Energy’s current tax year before filing its federal income tax return. The statute of limitations for these federal tax returns expires three years from each filing date.

(b)The statute of limitations for these Iowa tax returns expires three years from each filing date.

(c)The statute of limitations for these Wisconsin combined tax returns expires four years from each filing date.

Iowa Tax Reform - In 2018, Iowa tax reform was enacted, resulting in a reduction in the Iowa income tax rate from 12% to 9.8%, effective January 1, 2021, and the elimination of the deduction for federal income taxes, effective January 1, 2022, for taxes related to 2020 and prior.

IPL [Member]

Income Tax [Line Items]

Income Taxes

INCOME TAXES

Income Tax Expense (Benefit) - The components of “Income tax expense (benefit)” in the income statements were as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Current tax expense (benefit):
Federal	$1	$1	($7)	($21)	$6	($11)	$22	($11)	$12
State	3	8	24	(1)	(1)	24	6	7	13
IPL’s tax benefit riders	—	—	(4)	—	—	(4)	—	—	—
Deferred tax expense (benefit):
Federal	9	22	70	73	30	26	(75)	(9)	31
State	15	8	42	—	(2)	31	11	10	6
Production tax credits	(101)	(95)	(55)	(87)	(80)	(42)	(14)	(15)	(13)
Investment tax credits	(1)	(1)	(1)	—	—	—	(1)	(1)	—
	($74)	($57)	$69	($36)	($47)	$24	($51)	($19)	$49

Income Tax Rates - The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	Alliant Energy						IPL						WPL
	2021		2020		2019		2021		2020		2019		2021		2020		2019
Statutory federal income tax rate	21	%	21	%	21	%	21	%	21	%	21	%	21	%	21	%	21	%
State income taxes, net of federal benefits	2		2		7		(1)		(1)		8		6		6		6
Amortization of excess deferred taxes (Refer to Note 2)	(18)		(13)		(1)		(4)		(5)		—		(43)		(26)		(2)
Production tax credits	(17)		(17)		(9)		(27)		(28)		(13)		(6)		(7)		(5)
Effect of rate-making on property-related differences	(1)		(3)		(6)		(2)		(4)		(10)		(1)		(2)		(3)
Adjustment for prior period taxes	1		1		1		2		1		3		—		—		—
IPL’s tax benefit riders	—		—		(1)		—		—		(1)		—		—		—
Other items, net	—		(1)		(1)		—		—		—		(1)		—		—
Overall income tax rate	(12	%)	(10	%)	11	%	(11	%)	(16	%)	8	%	(24	%)	(8	%)	17	%

Deferred Tax Assets and Liabilities - The deferred tax assets and liabilities included on the balance sheets at December 31 arise from the following temporary differences (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Deferred tax liabilities:
Property	$2,389	$2,232	$1,416	$1,312	$913	$854
ATC Holdings	123	116	—	—	—	—
Other	111	101	76	83	50	41
Total deferred tax liabilities	2,623	2,449	1,492	1,395	963	895
Deferred tax assets:
Federal credit carryforwards	560	454	345	258	192	175
Net operating losses carryforwards - federal	39	77	36	71	—	1
Net operating losses carryforwards - state	38	37	3	1	—	—
Other	65	73	25	30	18	18
Subtotal deferred tax assets	702	641	409	360	210	194
Valuation allowances	(6)	(6)	—	—	—	(1)
Total deferred tax assets	696	635	409	360	210	193
Total deferred tax liabilities, net	$1,927	$1,814	$1,083	$1,035	$753	$702

Carryforwards - At December 31, 2021, carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy	IPL	WPL
Federal net operating losses	2037	$186	$172	$1
State net operating losses	2022-2041	619	28	2
Federal tax credits	2022-2041	560	345	192

Valuation Allowances - Alliant Energy currently expects its federal net operating losses carryforwards will not be fully utilized until 2023. Because taxable income must be reduced by federal net operating losses carryforwards prior to utilizing federal tax credit carryforwards, Alliant Energy currently does not expect to utilize 2002 vintage federal credit carryforwards prior to their expiration in 2022, resulting in valuation allowances as of December 31, 2021.

Uncertain Tax Positions - At December 31, 2021, 2020 and 2019, there were no uncertain tax positions or penalties accrued related to uncertain tax positions. As of December 31, 2021, no material changes to unrecognized tax benefits are expected during the next 12 months.

Open tax years - Tax years that remain subject to the statute of limitations in the major jurisdictions for each of Alliant Energy, IPL and WPL are as follows:

Consolidated federal income tax returns (a)	2018	-	2020
Consolidated Iowa income tax returns (b)	2018	-	2020
Wisconsin combined tax returns (c)	2017	-	2020

(a)The 2018 and 2019 federal tax returns are effectively settled as a result of participation in the IRS Compliance Assurance Program, which allows Alliant Energy and the IRS to work together to resolve issues related to Alliant Energy’s current tax year before filing its federal income tax return. The statute of limitations for these federal tax returns expires three years from each filing date.

(b)The statute of limitations for these Iowa tax returns expires three years from each filing date.

(c)The statute of limitations for these Wisconsin combined tax returns expires four years from each filing date.

Iowa Tax Reform - In 2018, Iowa tax reform was enacted, resulting in a reduction in the Iowa income tax rate from 12% to 9.8%, effective January 1, 2021, and the elimination of the deduction for federal income taxes, effective January 1, 2022, for taxes related to 2020 and prior.

WPL [Member]

Income Tax [Line Items]

Income Taxes

INCOME TAXES

Income Tax Expense (Benefit) - The components of “Income tax expense (benefit)” in the income statements were as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Current tax expense (benefit):
Federal	$1	$1	($7)	($21)	$6	($11)	$22	($11)	$12
State	3	8	24	(1)	(1)	24	6	7	13
IPL’s tax benefit riders	—	—	(4)	—	—	(4)	—	—	—
Deferred tax expense (benefit):
Federal	9	22	70	73	30	26	(75)	(9)	31
State	15	8	42	—	(2)	31	11	10	6
Production tax credits	(101)	(95)	(55)	(87)	(80)	(42)	(14)	(15)	(13)
Investment tax credits	(1)	(1)	(1)	—	—	—	(1)	(1)	—
	($74)	($57)	$69	($36)	($47)	$24	($51)	($19)	$49

Income Tax Rates - The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	Alliant Energy						IPL						WPL
	2021		2020		2019		2021		2020		2019		2021		2020		2019
Statutory federal income tax rate	21	%	21	%	21	%	21	%	21	%	21	%	21	%	21	%	21	%
State income taxes, net of federal benefits	2		2		7		(1)		(1)		8		6		6		6
Amortization of excess deferred taxes (Refer to Note 2)	(18)		(13)		(1)		(4)		(5)		—		(43)		(26)		(2)
Production tax credits	(17)		(17)		(9)		(27)		(28)		(13)		(6)		(7)		(5)
Effect of rate-making on property-related differences	(1)		(3)		(6)		(2)		(4)		(10)		(1)		(2)		(3)
Adjustment for prior period taxes	1		1		1		2		1		3		—		—		—
IPL’s tax benefit riders	—		—		(1)		—		—		(1)		—		—		—
Other items, net	—		(1)		(1)		—		—		—		(1)		—		—
Overall income tax rate	(12	%)	(10	%)	11	%	(11	%)	(16	%)	8	%	(24	%)	(8	%)	17	%

Deferred Tax Assets and Liabilities - The deferred tax assets and liabilities included on the balance sheets at December 31 arise from the following temporary differences (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Deferred tax liabilities:
Property	$2,389	$2,232	$1,416	$1,312	$913	$854
ATC Holdings	123	116	—	—	—	—
Other	111	101	76	83	50	41
Total deferred tax liabilities	2,623	2,449	1,492	1,395	963	895
Deferred tax assets:
Federal credit carryforwards	560	454	345	258	192	175
Net operating losses carryforwards - federal	39	77	36	71	—	1
Net operating losses carryforwards - state	38	37	3	1	—	—
Other	65	73	25	30	18	18
Subtotal deferred tax assets	702	641	409	360	210	194
Valuation allowances	(6)	(6)	—	—	—	(1)
Total deferred tax assets	696	635	409	360	210	193
Total deferred tax liabilities, net	$1,927	$1,814	$1,083	$1,035	$753	$702

Carryforwards - At December 31, 2021, carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy	IPL	WPL
Federal net operating losses	2037	$186	$172	$1
State net operating losses	2022-2041	619	28	2
Federal tax credits	2022-2041	560	345	192

Valuation Allowances - Alliant Energy currently expects its federal net operating losses carryforwards will not be fully utilized until 2023. Because taxable income must be reduced by federal net operating losses carryforwards prior to utilizing federal tax credit carryforwards, Alliant Energy currently does not expect to utilize 2002 vintage federal credit carryforwards prior to their expiration in 2022, resulting in valuation allowances as of December 31, 2021.

Uncertain Tax Positions - At December 31, 2021, 2020 and 2019, there were no uncertain tax positions or penalties accrued related to uncertain tax positions. As of December 31, 2021, no material changes to unrecognized tax benefits are expected during the next 12 months.

Open tax years - Tax years that remain subject to the statute of limitations in the major jurisdictions for each of Alliant Energy, IPL and WPL are as follows:

Consolidated federal income tax returns (a)	2018	-	2020
Consolidated Iowa income tax returns (b)	2018	-	2020
Wisconsin combined tax returns (c)	2017	-	2020

(a)The 2018 and 2019 federal tax returns are effectively settled as a result of participation in the IRS Compliance Assurance Program, which allows Alliant Energy and the IRS to work together to resolve issues related to Alliant Energy’s current tax year before filing its federal income tax return. The statute of limitations for these federal tax returns expires three years from each filing date.

(b)The statute of limitations for these Iowa tax returns expires three years from each filing date.

(c)The statute of limitations for these Wisconsin combined tax returns expires four years from each filing date.

Iowa Tax Reform - In 2018, Iowa tax reform was enacted, resulting in a reduction in the Iowa income tax rate from 12% to 9.8%, effective January 1, 2021, and the elimination of the deduction for federal income taxes, effective January 1, 2022, for taxes related to 2020 and prior.

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Benefit Plans

12 Months Ended

Dec. 31, 2021

Benefit Plans

BENEFIT PLANS(a) Pension and Other Postretirement Benefits Plans - Retirement benefits are provided to substantially all employees through various qualified and non-qualified non-contributory defined benefit pension plans (currently closed to new hires), and/or through defined contribution plans (including 401(k) savings plans). Benefits of the non-contributory defined benefit pension plans are based on the plan participant’s years of service, age and compensation. Benefits of the defined contribution plans are based on the plan participant’s years of service, age, compensation and contributions. Certain defined benefit postretirement health care and life benefits are provided to eligible retirees. In general, the retiree health care plans consist of fixed benefit subsidy structures and the retiree life insurance plans are non-contributory.

IPL and WPL account for their participation in Alliant Energy and Corporate Services sponsored plans as multiple-employer plans. For IPL and WPL, amounts below represent the amounts for their plan participants covered under plans they sponsor, as well as amounts directly assigned to them related to certain participants in the Alliant Energy and Corporate Services sponsored plans.

Assumptions - The assumptions for defined benefit pension and OPEB plans at the measurement date of December 31 were as follows:

	Defined Benefit Pension Plans									OPEB Plans
Alliant Energy	2021			2020			2019			2021	2020	2019
Discount rate for benefit obligations	2.91%			2.57%			3.48%			2.81%	2.31%	3.40%
Discount rate for net periodic cost	2.57%			3.48%			4.34%			2.31%	3.40%	4.24%
Expected rate of return on plan assets	7.10%			7.10%			7.60%			4.80%	4.50%	5.44%
Interest crediting rate for Alliant Energy Cash Balance Pension Plan	4.18%			4.76%			5.52%			N/A	N/A	N/A
Rate of compensation increase	3.30%	-	4.50%	3.65%	-	4.50%	3.65%	-	4.50%	N/A	N/A	N/A

	Qualified Defined Benefit Pension Plan			OPEB Plans
IPL	2021	2020	2019	2021	2020	2019
Discount rate for benefit obligations	2.94%	2.61%	3.51%	2.80%	2.28%	3.39%
Discount rate for net periodic cost	2.61%	3.51%	4.35%	2.28%	3.39%	4.23%
Expected rate of return on plan assets	7.10%	7.10%	7.60%	5.10%	4.50%	5.60%
Rate of compensation increase	3.30%	3.65%	3.65%	N/A	N/A	N/A

	Qualified Defined Benefit Pension Plan			OPEB Plans
WPL	2021	2020	2019	2021	2020	2019
Discount rate for benefit obligations	2.94%	2.64%	3.50%	2.79%	2.27%	3.39%
Discount rate for net periodic cost	2.64%	3.50%	4.35%	2.27%	3.39%	4.23%
Expected rate of return on plan assets	7.10%	7.10%	7.60%	4.02%	3.28%	3.81%
Rate of compensation increase	3.30%	3.65%	3.65%	N/A	N/A	N/A

Expected rate of return on plan assets - The expected rate of return on plan assets is based on projected asset class returns using target allocations. A forward-looking building blocks approach is used, and historical returns, survey information and capital market information are analyzed to support the expected rate of return on plan assets assumption. Refer to “Investment Strategy for Plan Assets” below for additional information related to investment strategy and mix of assets for the pension and OPEB plans.

Life Expectancy - The life expectancy assumption is used in determining the benefit obligation and net periodic benefit cost for defined benefit pension and OPEB plans. This assumption utilizes base mortality tables that were released in 2019 by the Society of Actuaries and mortality projection tables that were released in 2020 by the Society of Actuaries.

Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans are included below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements.

Alliant Energy	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$11	$11	$10	$4	$3	$3
Interest cost	34	43	50	5	7	9
Expected return on plan assets (a)	(69)	(70)	(60)	(5)	(5)	(5)
Amortization of prior service credit (b)	—	—	(1)	—	—	—
Amortization of actuarial loss (c)	39	34	36	5	3	3
Settlement losses (d)	—	12	—	—	—	—
	$15	$30	$35	$9	$8	$10

IPL	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$7	$7	$6	$1	$1	$1
Interest cost	16	20	23	2	3	3
Expected return on plan assets (a)	(32)	(33)	(28)	(3)	(4)	(4)
Amortization of actuarial loss (c)	17	15	15	2	1	2
Settlement losses (d)	—	7	—	—	—	—
	$8	$16	$16	$2	$1	$2

WPL	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$4	$4	$3	$1	$2	$1
Interest cost	15	19	21	2	3	3
Expected return on plan assets (a)	(31)	(31)	(26)	—	(1)	(1)
Amortization of prior service credit (b)	—	—	—	—	(1)	—
Amortization of actuarial loss (c)	19	16	18	2	2	2
	$7	$8	$16	$5	$5	$5

(a)The expected return on plan assets is based on the expected rate of return on plan assets and the fair value approach to the market-related value of plan assets.

(b)Unrecognized prior service credits for the OPEB plans are amortized over the average future service period to full eligibility of the participants of each plan.

(c)Unrecognized net actuarial gains or losses in excess of 10% of the greater of the plans’ benefit obligations or assets are amortized over the average future service lives of plan participants, except for the Alliant Energy Cash Balance Pension Plan where gains or losses outside the 10% threshold are amortized over the time period the participants are expected to receive benefits.

(d)Settlement losses related to payments made to retired executives of Alliant Energy and lump sum payments related to IPL’s qualified defined benefit pension plan.

Benefit Plan Assets and Obligations - A reconciliation of the funded status of qualified and non-qualified defined benefit pension and OPEB plans to the amounts recognized on the balance sheets at December 31 was as follows (in millions):

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$1,351	$1,280	$227	$214
Service cost	11	11	4	3
Interest cost	34	43	5	7
Plan participants’ contributions	—	—	5	4
Actuarial (gain) loss	(46)	132	(12)	18
Gross benefits paid	(99)	(115)	(19)	(19)
Net benefit obligation at December 31	1,251	1,351	210	227
Change in plan assets:
Fair value of plan assets at January 1	984	931	108	105
Actual return on plan assets	87	108	4	11
Employer contributions	39	60	8	7
Plan participants’ contributions	—	—	5	4
Gross benefits paid	(99)	(115)	(19)	(19)
Fair value of plan assets at December 31	1,011	984	106	108
Under funded status at December 31	($240)	($367)	($104)	($119)

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$13	$8
Current liabilities	(2)	(2)	(8)	(8)
Pension and other benefit obligations	(238)	(365)	(109)	(119)
Net amounts recognized at December 31	($240)	($367)	($104)	($119)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$429	$533	$38	$54
Prior service credit	(4)	(5)	(1)	(1)
	$425	$528	$37	$53

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$615	$581	$91	$86
Service cost	7	7	1	1
Interest cost	16	20	2	3
Plan participants’ contributions	—	—	2	1
Actuarial (gain) loss	(23)	60	(4)	8
Gross benefits paid	(48)	(53)	(8)	(8)
Net benefit obligation at December 31	567	615	84	91
Change in plan assets:
Fair value of plan assets at January 1	453	436	74	72
Actual return on plan assets	40	51	4	7
Employer contributions	17	19	2	2
Plan participants’ contributions	—	—	2	1
Gross benefits paid	(48)	(53)	(8)	(8)
Fair value of plan assets at December 31	462	453	74	74
Under funded status at December 31	($105)	($162)	($10)	($17)

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$10	$4
Current liabilities	—	(1)	(2)	(2)
Pension and other benefit obligations	(105)	(161)	(18)	(19)
Net amounts recognized at December 31	($105)	($162)	($10)	($17)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$180	$228	$13	$20
Prior service credit	(1)	(1)	—	—
	$179	$227	$13	$20

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$588	$550	$89	$85
Service cost	4	4	1	2
Interest cost	15	19	2	3
Plan participants’ contributions	—	—	2	2
Actuarial (gain) loss	(18)	55	(5)	5
Gross benefits paid	(43)	(40)	(8)	(8)
Net benefit obligation at December 31	546	588	81	89
Change in plan assets:
Fair value of plan assets at January 1	436	406	18	17
Actual return on plan assets	39	48	—	2
Employer contributions	18	22	5	5
Plan participants’ contributions	—	—	2	2
Gross benefits paid	(43)	(40)	(8)	(8)
Fair value of plan assets at December 31	450	436	17	18
Under funded status at December 31	($96)	($152)	($64)	($71)

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$3	$3
Current liabilities	—	—	(6)	(6)
Pension and other benefit obligations	(96)	(152)	(61)	(68)
Net amounts recognized at December 31	($96)	($152)	($64)	($71)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$188	$233	$18	$25
Prior service credit	(1)	(1)	(1)	(1)
	$187	$232	$17	$24

Actuarial gains related to benefit obligations in 2021 for defined benefit pension and OPEB plans were primarily due to increases in the discount rates. Actuarial losses related to benefit obligations in 2020 for defined benefit pension and OPEB plans were primarily due to decreases in the discount rates, partially offset by the impact of updated mortality projection tables.

Accumulated benefit obligations, aggregate amounts applicable to defined benefit pension and OPEB plans with accumulated benefit obligations in excess of plan assets, as well as defined benefit pension plans with projected benefit obligations in excess of plan assets as of the December 31 measurement date are as follows (in millions):

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Accumulated benefit obligations	$1,214	$1,305	$210	$227
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	1,214	1,305	210	227
Fair value of plan assets	1,011	984	106	108
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	1,251	1,351	N/A	N/A
Fair value of plan assets	1,011	984	N/A	N/A

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Accumulated benefit obligations	$546	$589	$84	$91
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	546	589	84	91
Fair value of plan assets	462	453	74	74
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	567	615	N/A	N/A
Fair value of plan assets	462	453	N/A	N/A

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Accumulated benefit obligations	$532	$573	$81	$89
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	532	573	81	89
Fair value of plan assets	450	436	17	18
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	546	588	N/A	N/A
Fair value of plan assets	450	436	N/A	N/A

In addition to the amounts recognized in regulatory assets in the above tables for IPL and WPL, regulatory assets were recognized for amounts associated with Corporate Services employees participating in other Alliant Energy sponsored benefit plans that were allocated to IPL and WPL at December 31 as follows (in millions):

	IPL		WPL
	2021	2020	2021	2020
Regulatory assets	$35	$44	$30	$34

Estimated Future Employer Contributions and Benefit Payments - Estimated funding for the qualified and non-qualified defined benefit pension and OPEB plans for 2022 is as follows (in millions):

	Alliant Energy	IPL	WPL
Defined benefit pension plans (a)	$2	$—	$—
OPEB plans	8	2	6

(a)Alliant Energy sponsors several non-qualified defined benefit pension plans that cover certain current and former key employees of IPL and WPL. Alliant Energy allocates pension costs to IPL and WPL for these plans. In addition, IPL and WPL amounts reflect funding for their non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.

Expected benefit payments for the qualified and non-qualified defined benefit plans, which reflect expected future service, as appropriate, are as follows (in millions):

Alliant Energy	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$85	$83	$82	$82	$83	$387
OPEB	18	17	17	17	16	71
	$103	$100	$99	$99	$99	$458

IPL	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$41	$40	$39	$39	$38	$174
OPEB	7	7	7	7	7	28
	$48	$47	$46	$46	$45	$202

WPL	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$37	$36	$35	$35	$34	$163
OPEB	7	7	7	7	6	27
	$44	$43	$42	$42	$40	$190

Investment Strategy for Plan Assets - Investment strategies for defined benefit pension and OPEB plan assets combine preservation of principal and prudent risk-taking to protect the integrity of plan assets, in order to meet the obligations to plan participants while minimizing benefit costs over the long term. Investment risk of plan assets is mitigated through diversification, including U.S. and international equity, fixed income and global asset strategies. Global asset strategies may include investments in global equity, global debt and currencies.

Defined Benefit Pension Plan Assets - The asset mix of defined benefit pension plans is governed by allocation targets. The asset allocation is monitored regularly, and appropriate steps are taken as needed to rebalance the assets within the prescribed ranges. An overlay management service is also used to help maintain target allocations and meet liquidity needs. The overlay manager is authorized to use derivative financial instruments to facilitate this service. For separately managed accounts, prohibited investments include, but are not limited to, direct ownership of real estate, oil and gas limited partnerships, securities of the managers’ firms or affiliate firms, and Alliant Energy securities. At December 31, 2021, the current target ranges and actual allocations for the defined benefit pension plan assets were as follows:

	Target Range			Actual
	Allocation			Allocation
Cash and equivalents	0%	-	5%	3%
Equity securities - U.S.	14%	-	54%	34%
Equity securities - international	11%	-	31%	21%
Global asset securities	5%	-	15%	9%
Fixed income securities	25%	-	45%	33%

Other Postretirement Benefits Plan Assets - OPEB plan assets are comprised of specific assets within certain defined benefit pension plans (401(h) assets) as well as assets held in VEBA trusts. The investment strategy of the Corporate Services 401(h) assets mirrors those of the defined benefit pension plans, which are discussed above. For VEBA trusts with assets greater than $5 million and the WPL 401(h) assets, the mix among asset classes is governed by allocation targets. The asset allocation is monitored regularly, and appropriate steps are taken as needed to rebalance the assets within the prescribed ranges. At December 31, 2021, the current target ranges and actual allocations for VEBA trusts with assets greater than $5 million and the WPL 401(h) assets were as follows:

	Target Range			Actual
	Allocation			Allocation
Cash and equivalents	0%	-	5%	1%
Equity securities - U.S.	0%	-	55%	35%
Fixed income securities	40%	-	100%	64%

Fair Value Measurements - Fair value measurement accounting establishes three levels of fair value hierarchy that prioritize the inputs to valuation techniques used to measure fair value. Refer to Note 16 for discussion of levels within the fair value hierarchy. Level 1 items include investments in securities held in registered investment companies and directly held equity securities, which are valued at the closing price reported in the active market in which the securities are traded. Level 2 items include fixed income securities consisting of corporate and government bonds, which are valued at the closing price reported in the active market for similar assets in which the individual securities are traded or based on yields currently available on comparable securities of issuers with similar credit ratings. Certain investments that are measured at fair value using the net asset value practical expedient have not been classified in the fair value hierarchy. These fair value amounts are included below to reconcile the fair value hierarchy to the respective total plan assets.

At December 31, the fair values of qualified and non-qualified defined benefit pension plan assets were as follows (in millions):

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
Alliant Energy	Value	1	2	3	Value	1	2	3
Cash and equivalents	$35	$—	$35	$—	$46	$—	$46	$—
Equity securities - U.S.	256	256	—	—	182	182	—	—
Equity securities - international	—	—	—	—	151	151	—	—
Global asset securities	52	52	—	—	45	45	—	—
Fixed income securities	191	47	144	—	134	56	78	—
Total assets in fair value hierarchy	534	$355	$179	$—	558	$434	$124	$—
Assets measured at net asset value	477				426
Accrued investment income	1				1
Due to brokers, net (pending trades with brokers)	(1)				(1)
Total pension plan assets	$1,011				$984

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
IPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$16	$—	$16	$—	$21	$—	$21	$—
Equity securities - U.S.	117	117	—	—	84	84	—	—
Equity securities - international	—	—	—	—	69	69	—	—
Global asset securities	24	24	—	—	21	21	—	—
Fixed income securities	87	21	66	—	62	26	36	—
Total assets in fair value hierarchy	244	$162	$82	$—	257	$200	$57	$—
Assets measured at net asset value	218				196
Total pension plan assets	$462				$453

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
WPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$16	$—	$16	$—	$20	$—	$20	$—
Equity securities - U.S.	114	114	—	—	81	81	—	—
Equity securities - international	—	—	—	—	67	67	—	—
Global asset securities	23	23	—	—	20	20	—	—
Fixed income securities	85	21	64	—	59	25	34	—
Total assets in fair value hierarchy	238	$158	$80	$—	247	$193	$54	$—
Assets measured at net asset value	212				189
Total pension plan assets	$450				$436

At December 31, the fair values of OPEB plan assets were as follows (in millions):

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
Alliant Energy	Value	1	2	3	Value	1	2	3
Cash and equivalents	$5	$—	$5	$—	$2	$—	$2	$—
Equity securities - U.S.	11	11	—	—	4	4	—	—
Equity securities - international	—	—	—	—	3	3	—	—
Global asset securities	1	1	—	—	—	—	—	—
Fixed income securities	60	58	2	—	72	71	1	—
Total assets in fair value hierarchy	77	$70	$7	$—	81	$78	$3	$—
Assets measured at net asset value	29				27
Total OPEB plan assets	$106				$108

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
IPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$1	$—	$1	$—	$1	$—	$1	$—
Equity securities - U.S.	8	8	—	—	—	—	—	—
Fixed income securities	42	42	—	—	51	51	—	—
Total assets in fair value hierarchy	51	$50	$1	$—	52	$51	$1	$—
Assets measured at net asset value	23				22
Total OPEB plan assets	$74				$74

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
WPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$1	$—	$1	$—	$—	$—	$—	$—
Equity securities - U.S.	1	1	—	—	—	—	—	—
Fixed income securities	15	15	—	—	18	18	—	—
Total OPEB plan assets	$17	$16	$1	$—	$18	$18	$—	$—

For the various defined benefit pension and OPEB plans, Alliant Energy common stock represented less than 1% of assets directly held in the plans at December 31, 2021 and 2020.

401(k) Savings Plans - A significant number of employees participate in defined contribution retirement plans (401(k) savings plans). Alliant Energy common stock directly held by participants represented 9% and 9% of total assets in the 401(k) savings plans at December 31, 2021 and 2020, respectively. Costs related to the 401(k) savings plans, which are partially based on the participants’ contributions and include allocated costs associated with Corporate Services employees for IPL and WPL, were as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
401(k) costs	$26	$25	$25	$13	$13	$13	$12	$12	$12

(b) Equity-based Compensation Plans - In 2020, Alliant Energy’s shareowners approved the 2020 OIP, which permits the grant of shares of Alliant Energy common stock, restricted stock, restricted stock units, performance shares, performance units, and other stock-based or cash-based awards to key employees. The 2020 OIP replaced the Amended and Restated 2010 OIP, which permitted similar grants. At December 31, 2021, performance shares and restricted stock units (performance- and time-vesting) were outstanding under the 2020 OIP and the Amended and Restated 2010 OIP, and 9 million shares of Alliant Energy common stock remained available for grants under the 2020 OIP. Alliant Energy satisfies share payouts related to equity awards through the issuance of new shares of its common stock. Alliant Energy also granted cash-based long-term awards, including performance units, restricted cash awards and restricted units, to certain key employees, under the DLIP. At December 31, 2021, no awards were outstanding under the DLIP. Nonvested awards generally do not have non-forfeitable rights to dividends or dividend equivalents when dividends are paid to common shareowners. A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Compensation expense	$14	$16	$26	$8	$9	$15	$6	$6	$10
Income tax benefits	4	4	7	2	2	4	2	2	3

As of December 31, 2021, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $5 million, $3 million and $2 million, respectively, which is expected to be recognized over a weighted average period of between one year and two years. Share-based compensation expense is recognized on a straight-line basis over the requisite service periods and is recorded in “Other operation and maintenance” in the income statements. As of December 31, 2021, 653,956 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

Performance Shares - Equity Awards - Payouts of 2021, 2020 and 2019 performance shares are contingent upon achievement over a three-year period of specified performance criteria, which currently is total shareowner return relative to an investor-owned utility peer group. Performance shares granted in 2021, 2020 and 2019 are to be paid out in shares of Alliant Energy common stock and are accounted for as equity awards. The fair value of each of these performance shares is based on the fair value of the underlying common stock on the grant date and the probability of satisfying the market condition contained in the agreement during a three-year performance period. The actual number of these performance shares that will be paid out upon vesting is dependent upon actual performance and may range from zero to 200% of the target number of shares. If minimum performance targets are not met during the performance period, these performance shares are forfeited. Compensation expense is recorded ratably over the performance period based on the fair value of the awards at the grant date. A summary of the 2021, 2020 and 2019 performance shares activity, with amounts representing the target number of awards, was as follows:

	2021		2020		2019
	Performance Shares - Equity	Weighted Average Grant Date Fair Value	Performance Shares - Equity	Weighted Average Grant Date Fair Value	Performance Shares - Equity	Weighted Average Grant Date Fair Value
Nonvested awards, January 1	129,156	$54.63	74,193	$47.44	—	$—
Granted	73,112	46.19	56,204	64.04	91,816	47.23
Forfeited	(5,839)	51.07	(1,241)	50.94	(17,623)	46.35
Nonvested awards, December 31	196,429	51.59	129,156	54.63	74,193	47.44

Performance Shares and Performance Units - Liability Awards - Payouts of performance shares granted prior to 2019 under the Amended and Restated 2010 OIP and performance units granted prior to 2019 under the DLIP to key employees were contingent upon achievement over three-year periods of specified performance criteria, which was total shareowner return relative to an investor-owned utility peer group. Performance shares granted prior to 2019 were able to be paid out in shares of Alliant Energy common stock, cash or a combination of cash and stock. Performance units granted prior to 2019 were paid out in cash. Alliant Energy assumed it would make future payouts of its performance shares granted prior to 2019 and performance units in cash; therefore, these performance shares and performance units were accounted for as liability awards. The fair value of each performance share and performance unit accounted for as a liability award was based on the closing market price of one share of Alliant Energy common stock at the end of the performance period. The actual payout for performance shares and performance units was dependent upon actual performance and may range from zero to 200% of the

target number of awards. Compensation expense for these performance shares and performance units was recorded ratably over the performance period based on the fair value of the awards at each reporting period. A summary of these performance shares and performance units activity, with amounts representing the target number of awards, was as follows:

	Performance Shares (granted prior to 2019)			Performance Units (granted prior to 2019)
	2021	2020	2019	2021	2020	2019
Nonvested awards, January 1	68,307	131,872	203,188	16,801	34,574	57,761
Vested	(68,307)	(63,565)	(66,322)	(16,801)	(16,661)	(20,131)
Forfeited	—	—	(4,994)	—	(1,112)	(3,056)
Nonvested awards, December 31	—	68,307	131,872	—	16,801	34,574

Vested Awards - Certain performance shares and performance units vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows:

	Performance Shares (granted prior to 2019)			Performance Units (granted prior to 2019)
	2021	2020	2019	2021	2020	2019
	2018 Grant	2017 Grant	2016 Grant	2018 Grant	2017 Grant	2016 Grant
Performance awards vested	68,307	63,565	66,322	16,801	16,661	20,131
Percentage of target number of performance awards	172.5%	155.0%	142.5%	172.5%	155.0%	142.5%
Aggregate payout value (in millions)	$7	$6	$4	$2	$2	$1
Payout - cash (in millions)	$5	$5	$4	$2	$2	$1
Payout - common stock shares issued	13,644	9,543	6,447	N/A	N/A	N/A

Restricted Stock Units - Equity Awards - Payouts of 2021, 2020 and 2019 restricted stock units are based on the expiration of a three-year time-vesting period. Restricted stock units granted in 2021, 2020 and 2019 are to be paid out in shares of Alliant Energy common stock and are accounted for as equity awards. The fair value of each of these restricted stock units is based on the closing market price of one share of Alliant Energy common stock on the grant date of the award. Compensation expense is recorded ratably over the performance period based on the fair value of the awards on the grant date. A summary of the 2021, 2020 and 2019 restricted stock units activity was as follows:

	2021		2020		2019
	Restricted Stock Units - Equity	Weighted Average Grant Date Fair Value	Restricted Stock Units - Equity	Weighted Average Grant Date Fair Value	Restricted Stock Units - Equity	Weighted Average Grant Date Fair Value
Nonvested units, January 1	146,549	$51.54	89,281	$46.04	—	$—
Granted	80,152	48.65	61,056	59.42	105,348	45.98
Forfeited	(8,882)	49.84	(3,788)	49.01	(16,067)	45.63
Nonvested units, December 31	217,819	50.54	146,549	51.54	89,281	46.04

Restricted Stock Units - Liability Awards - Payouts of restricted stock units granted prior to 2019 were based on the expiration of a three-year time-vesting period and were able to be paid out in shares of Alliant Energy common stock, cash or a combination of cash and stock. Alliant Energy assumed it would make future payouts of its restricted stock units granted prior to 2019 in cash; therefore, restricted stock units granted prior to 2019 were accounted for as liability awards. The fair value of each restricted stock unit granted prior to 2019 was based on the closing market price of one share of Alliant Energy common stock at the end of the time-vesting period. Compensation expense was recorded ratably over the performance period based on the fair value of the awards at each reporting period. A summary of the restricted stock units granted prior to 2019 activity was as follows:

	2021	2020	2019
Nonvested units, January 1	58,550	113,033	174,163
Vested	(58,550)	(54,483)	(56,849)
Forfeited	—	—	(4,281)
Nonvested units, December 31	—	58,550	113,033

Performance Restricted Stock Units - Equity Awards - Payouts of performance restricted stock units are based upon achievement of certain performance targets during a three-year performance period, which currently includes specified growth of consolidated net income from continuing operations. The actual number of units that will be paid out upon vesting is dependent upon actual performance and may range from zero to 200% of the target number of units. If minimum performance targets are not met during the performance period, these units are forfeited. Performance restricted stock units are to be paid out in shares and are accounted for as equity awards. The fair value of each performance restricted stock unit is based on the closing market price of one share of Alliant Energy common stock on the grant date of the award. Compensation expense is recorded ratably over the performance period based on a probability assessment of payouts for the awards at each reporting period. A summary of the performance restricted stock units activity, with amounts representing the target number of units, was as follows:

	2021		2020		2019
	Units	Weighted Average Grant Date Fair Value	Units	Weighted Average Grant Date Fair Value	Units	Weighted Average Grant Date Fair Value
Nonvested units, January 1	197,463	$47.31	206,065	$41.50	203,188	$37.23
Granted	73,112	48.66	56,204	59.37	91,816	46.10
Vested	(68,307)	38.60	(63,565)	39.12	(66,322)	33.93
Forfeited	(5,839)	50.46	(1,241)	49.25	(22,617)	44.00
Nonvested units, December 31	196,429	50.74	197,463	47.31	206,065	41.50

(c) Deferred Compensation Plan - Alliant Energy maintains a DCP under which key employees may defer up to 100% of base salary and short-term cash incentive compensation and directors may elect to defer all or part of their retainer and committee fees. Key employees who have made the maximum allowed contribution to the Alliant Energy 401(k) Savings Plan may receive an additional credit to the DCP. Key employees and directors may elect to have their deferrals credited to a company stock account, an interest account, equity accounts or mutual fund accounts based on certain benchmark funds.

Company Stock Account - The DCP does not permit diversification of deferrals credited to the company stock account and all distributions from participants’ company stock accounts are made in the form of shares of Alliant Energy common stock. The deferred compensation obligations for participants’ company stock accounts are recorded in “Additional paid-in capital” and the shares of Alliant Energy common stock held in a rabbi trust to satisfy this obligation are recorded in “Shares in deferred compensation trust” on Alliant Energy’s balance sheets. At December 31, the carrying value of the deferred compensation obligation for the company stock account and the shares in the deferred compensation trust based on the historical value of the shares of Alliant Energy common stock contributed to the rabbi trust, and the fair market value of the shares held in the rabbi trust, were as follows (in millions):

	2021	2020
Carrying value	$12	$11
Fair market value	24	20

Interest, Equity and Mutual Fund Accounts - Distributions from participants’ interest, equity and mutual fund accounts are in the form of cash payments. The deferred compensation obligations for participants’ interest, equity and mutual fund accounts are recorded in “Pension and other benefit obligations” on the balance sheets. At December 31, 2021 and 2020, the carrying value of Alliant Energy’s deferred compensation obligations for participants’ interest, equity and mutual fund accounts, which approximates fair market value, was $22 million and $22 million, respectively.

IPL [Member]

Benefit Plans

BENEFIT PLANS(a) Pension and Other Postretirement Benefits Plans - Retirement benefits are provided to substantially all employees through various qualified and non-qualified non-contributory defined benefit pension plans (currently closed to new hires), and/or through defined contribution plans (including 401(k) savings plans). Benefits of the non-contributory defined benefit pension plans are based on the plan participant’s years of service, age and compensation. Benefits of the defined contribution plans are based on the plan participant’s years of service, age, compensation and contributions. Certain defined benefit postretirement health care and life benefits are provided to eligible retirees. In general, the retiree health care plans consist of fixed benefit subsidy structures and the retiree life insurance plans are non-contributory.

IPL and WPL account for their participation in Alliant Energy and Corporate Services sponsored plans as multiple-employer plans. For IPL and WPL, amounts below represent the amounts for their plan participants covered under plans they sponsor, as well as amounts directly assigned to them related to certain participants in the Alliant Energy and Corporate Services sponsored plans.

Assumptions - The assumptions for defined benefit pension and OPEB plans at the measurement date of December 31 were as follows:

	Defined Benefit Pension Plans									OPEB Plans
Alliant Energy	2021			2020			2019			2021	2020	2019
Discount rate for benefit obligations	2.91%			2.57%			3.48%			2.81%	2.31%	3.40%
Discount rate for net periodic cost	2.57%			3.48%			4.34%			2.31%	3.40%	4.24%
Expected rate of return on plan assets	7.10%			7.10%			7.60%			4.80%	4.50%	5.44%
Interest crediting rate for Alliant Energy Cash Balance Pension Plan	4.18%			4.76%			5.52%			N/A	N/A	N/A
Rate of compensation increase	3.30%	-	4.50%	3.65%	-	4.50%	3.65%	-	4.50%	N/A	N/A	N/A

	Qualified Defined Benefit Pension Plan			OPEB Plans
IPL	2021	2020	2019	2021	2020	2019
Discount rate for benefit obligations	2.94%	2.61%	3.51%	2.80%	2.28%	3.39%
Discount rate for net periodic cost	2.61%	3.51%	4.35%	2.28%	3.39%	4.23%
Expected rate of return on plan assets	7.10%	7.10%	7.60%	5.10%	4.50%	5.60%
Rate of compensation increase	3.30%	3.65%	3.65%	N/A	N/A	N/A

	Qualified Defined Benefit Pension Plan			OPEB Plans
WPL	2021	2020	2019	2021	2020	2019
Discount rate for benefit obligations	2.94%	2.64%	3.50%	2.79%	2.27%	3.39%
Discount rate for net periodic cost	2.64%	3.50%	4.35%	2.27%	3.39%	4.23%
Expected rate of return on plan assets	7.10%	7.10%	7.60%	4.02%	3.28%	3.81%
Rate of compensation increase	3.30%	3.65%	3.65%	N/A	N/A	N/A

Expected rate of return on plan assets - The expected rate of return on plan assets is based on projected asset class returns using target allocations. A forward-looking building blocks approach is used, and historical returns, survey information and capital market information are analyzed to support the expected rate of return on plan assets assumption. Refer to “Investment Strategy for Plan Assets” below for additional information related to investment strategy and mix of assets for the pension and OPEB plans.

Life Expectancy - The life expectancy assumption is used in determining the benefit obligation and net periodic benefit cost for defined benefit pension and OPEB plans. This assumption utilizes base mortality tables that were released in 2019 by the Society of Actuaries and mortality projection tables that were released in 2020 by the Society of Actuaries.

Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans are included below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements.

Alliant Energy	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$11	$11	$10	$4	$3	$3
Interest cost	34	43	50	5	7	9
Expected return on plan assets (a)	(69)	(70)	(60)	(5)	(5)	(5)
Amortization of prior service credit (b)	—	—	(1)	—	—	—
Amortization of actuarial loss (c)	39	34	36	5	3	3
Settlement losses (d)	—	12	—	—	—	—
	$15	$30	$35	$9	$8	$10

IPL	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$7	$7	$6	$1	$1	$1
Interest cost	16	20	23	2	3	3
Expected return on plan assets (a)	(32)	(33)	(28)	(3)	(4)	(4)
Amortization of actuarial loss (c)	17	15	15	2	1	2
Settlement losses (d)	—	7	—	—	—	—
	$8	$16	$16	$2	$1	$2

WPL	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$4	$4	$3	$1	$2	$1
Interest cost	15	19	21	2	3	3
Expected return on plan assets (a)	(31)	(31)	(26)	—	(1)	(1)
Amortization of prior service credit (b)	—	—	—	—	(1)	—
Amortization of actuarial loss (c)	19	16	18	2	2	2
	$7	$8	$16	$5	$5	$5

(a)The expected return on plan assets is based on the expected rate of return on plan assets and the fair value approach to the market-related value of plan assets.

(b)Unrecognized prior service credits for the OPEB plans are amortized over the average future service period to full eligibility of the participants of each plan.

(c)Unrecognized net actuarial gains or losses in excess of 10% of the greater of the plans’ benefit obligations or assets are amortized over the average future service lives of plan participants, except for the Alliant Energy Cash Balance Pension Plan where gains or losses outside the 10% threshold are amortized over the time period the participants are expected to receive benefits.

(d)Settlement losses related to payments made to retired executives of Alliant Energy and lump sum payments related to IPL’s qualified defined benefit pension plan.

Benefit Plan Assets and Obligations - A reconciliation of the funded status of qualified and non-qualified defined benefit pension and OPEB plans to the amounts recognized on the balance sheets at December 31 was as follows (in millions):

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$1,351	$1,280	$227	$214
Service cost	11	11	4	3
Interest cost	34	43	5	7
Plan participants’ contributions	—	—	5	4
Actuarial (gain) loss	(46)	132	(12)	18
Gross benefits paid	(99)	(115)	(19)	(19)
Net benefit obligation at December 31	1,251	1,351	210	227
Change in plan assets:
Fair value of plan assets at January 1	984	931	108	105
Actual return on plan assets	87	108	4	11
Employer contributions	39	60	8	7
Plan participants’ contributions	—	—	5	4
Gross benefits paid	(99)	(115)	(19)	(19)
Fair value of plan assets at December 31	1,011	984	106	108
Under funded status at December 31	($240)	($367)	($104)	($119)

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$13	$8
Current liabilities	(2)	(2)	(8)	(8)
Pension and other benefit obligations	(238)	(365)	(109)	(119)
Net amounts recognized at December 31	($240)	($367)	($104)	($119)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$429	$533	$38	$54
Prior service credit	(4)	(5)	(1)	(1)
	$425	$528	$37	$53

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$615	$581	$91	$86
Service cost	7	7	1	1
Interest cost	16	20	2	3
Plan participants’ contributions	—	—	2	1
Actuarial (gain) loss	(23)	60	(4)	8
Gross benefits paid	(48)	(53)	(8)	(8)
Net benefit obligation at December 31	567	615	84	91
Change in plan assets:
Fair value of plan assets at January 1	453	436	74	72
Actual return on plan assets	40	51	4	7
Employer contributions	17	19	2	2
Plan participants’ contributions	—	—	2	1
Gross benefits paid	(48)	(53)	(8)	(8)
Fair value of plan assets at December 31	462	453	74	74
Under funded status at December 31	($105)	($162)	($10)	($17)

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$10	$4
Current liabilities	—	(1)	(2)	(2)
Pension and other benefit obligations	(105)	(161)	(18)	(19)
Net amounts recognized at December 31	($105)	($162)	($10)	($17)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$180	$228	$13	$20
Prior service credit	(1)	(1)	—	—
	$179	$227	$13	$20

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$588	$550	$89	$85
Service cost	4	4	1	2
Interest cost	15	19	2	3
Plan participants’ contributions	—	—	2	2
Actuarial (gain) loss	(18)	55	(5)	5
Gross benefits paid	(43)	(40)	(8)	(8)
Net benefit obligation at December 31	546	588	81	89
Change in plan assets:
Fair value of plan assets at January 1	436	406	18	17
Actual return on plan assets	39	48	—	2
Employer contributions	18	22	5	5
Plan participants’ contributions	—	—	2	2
Gross benefits paid	(43)	(40)	(8)	(8)
Fair value of plan assets at December 31	450	436	17	18
Under funded status at December 31	($96)	($152)	($64)	($71)

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$3	$3
Current liabilities	—	—	(6)	(6)
Pension and other benefit obligations	(96)	(152)	(61)	(68)
Net amounts recognized at December 31	($96)	($152)	($64)	($71)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$188	$233	$18	$25
Prior service credit	(1)	(1)	(1)	(1)
	$187	$232	$17	$24

Actuarial gains related to benefit obligations in 2021 for defined benefit pension and OPEB plans were primarily due to increases in the discount rates. Actuarial losses related to benefit obligations in 2020 for defined benefit pension and OPEB plans were primarily due to decreases in the discount rates, partially offset by the impact of updated mortality projection tables.

Accumulated benefit obligations, aggregate amounts applicable to defined benefit pension and OPEB plans with accumulated benefit obligations in excess of plan assets, as well as defined benefit pension plans with projected benefit obligations in excess of plan assets as of the December 31 measurement date are as follows (in millions):

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Accumulated benefit obligations	$1,214	$1,305	$210	$227
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	1,214	1,305	210	227
Fair value of plan assets	1,011	984	106	108
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	1,251	1,351	N/A	N/A
Fair value of plan assets	1,011	984	N/A	N/A

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Accumulated benefit obligations	$546	$589	$84	$91
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	546	589	84	91
Fair value of plan assets	462	453	74	74
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	567	615	N/A	N/A
Fair value of plan assets	462	453	N/A	N/A

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Accumulated benefit obligations	$532	$573	$81	$89
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	532	573	81	89
Fair value of plan assets	450	436	17	18
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	546	588	N/A	N/A
Fair value of plan assets	450	436	N/A	N/A

In addition to the amounts recognized in regulatory assets in the above tables for IPL and WPL, regulatory assets were recognized for amounts associated with Corporate Services employees participating in other Alliant Energy sponsored benefit plans that were allocated to IPL and WPL at December 31 as follows (in millions):

	IPL		WPL
	2021	2020	2021	2020
Regulatory assets	$35	$44	$30	$34

Estimated Future Employer Contributions and Benefit Payments - Estimated funding for the qualified and non-qualified defined benefit pension and OPEB plans for 2022 is as follows (in millions):

	Alliant Energy	IPL	WPL
Defined benefit pension plans (a)	$2	$—	$—
OPEB plans	8	2	6

(a)Alliant Energy sponsors several non-qualified defined benefit pension plans that cover certain current and former key employees of IPL and WPL. Alliant Energy allocates pension costs to IPL and WPL for these plans. In addition, IPL and WPL amounts reflect funding for their non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.

Expected benefit payments for the qualified and non-qualified defined benefit plans, which reflect expected future service, as appropriate, are as follows (in millions):

Alliant Energy	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$85	$83	$82	$82	$83	$387
OPEB	18	17	17	17	16	71
	$103	$100	$99	$99	$99	$458

IPL	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$41	$40	$39	$39	$38	$174
OPEB	7	7	7	7	7	28
	$48	$47	$46	$46	$45	$202

WPL	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$37	$36	$35	$35	$34	$163
OPEB	7	7	7	7	6	27
	$44	$43	$42	$42	$40	$190

Investment Strategy for Plan Assets - Investment strategies for defined benefit pension and OPEB plan assets combine preservation of principal and prudent risk-taking to protect the integrity of plan assets, in order to meet the obligations to plan participants while minimizing benefit costs over the long term. Investment risk of plan assets is mitigated through diversification, including U.S. and international equity, fixed income and global asset strategies. Global asset strategies may include investments in global equity, global debt and currencies.

Defined Benefit Pension Plan Assets - The asset mix of defined benefit pension plans is governed by allocation targets. The asset allocation is monitored regularly, and appropriate steps are taken as needed to rebalance the assets within the prescribed ranges. An overlay management service is also used to help maintain target allocations and meet liquidity needs. The overlay manager is authorized to use derivative financial instruments to facilitate this service. For separately managed accounts, prohibited investments include, but are not limited to, direct ownership of real estate, oil and gas limited partnerships, securities of the managers’ firms or affiliate firms, and Alliant Energy securities. At December 31, 2021, the current target ranges and actual allocations for the defined benefit pension plan assets were as follows:

	Target Range			Actual
	Allocation			Allocation
Cash and equivalents	0%	-	5%	3%
Equity securities - U.S.	14%	-	54%	34%
Equity securities - international	11%	-	31%	21%
Global asset securities	5%	-	15%	9%
Fixed income securities	25%	-	45%	33%

Other Postretirement Benefits Plan Assets - OPEB plan assets are comprised of specific assets within certain defined benefit pension plans (401(h) assets) as well as assets held in VEBA trusts. The investment strategy of the Corporate Services 401(h) assets mirrors those of the defined benefit pension plans, which are discussed above. For VEBA trusts with assets greater than $5 million and the WPL 401(h) assets, the mix among asset classes is governed by allocation targets. The asset allocation is monitored regularly, and appropriate steps are taken as needed to rebalance the assets within the prescribed ranges. At December 31, 2021, the current target ranges and actual allocations for VEBA trusts with assets greater than $5 million and the WPL 401(h) assets were as follows:

	Target Range			Actual
	Allocation			Allocation
Cash and equivalents	0%	-	5%	1%
Equity securities - U.S.	0%	-	55%	35%
Fixed income securities	40%	-	100%	64%

Fair Value Measurements - Fair value measurement accounting establishes three levels of fair value hierarchy that prioritize the inputs to valuation techniques used to measure fair value. Refer to Note 16 for discussion of levels within the fair value hierarchy. Level 1 items include investments in securities held in registered investment companies and directly held equity securities, which are valued at the closing price reported in the active market in which the securities are traded. Level 2 items include fixed income securities consisting of corporate and government bonds, which are valued at the closing price reported in the active market for similar assets in which the individual securities are traded or based on yields currently available on comparable securities of issuers with similar credit ratings. Certain investments that are measured at fair value using the net asset value practical expedient have not been classified in the fair value hierarchy. These fair value amounts are included below to reconcile the fair value hierarchy to the respective total plan assets.

At December 31, the fair values of qualified and non-qualified defined benefit pension plan assets were as follows (in millions):

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
Alliant Energy	Value	1	2	3	Value	1	2	3
Cash and equivalents	$35	$—	$35	$—	$46	$—	$46	$—
Equity securities - U.S.	256	256	—	—	182	182	—	—
Equity securities - international	—	—	—	—	151	151	—	—
Global asset securities	52	52	—	—	45	45	—	—
Fixed income securities	191	47	144	—	134	56	78	—
Total assets in fair value hierarchy	534	$355	$179	$—	558	$434	$124	$—
Assets measured at net asset value	477				426
Accrued investment income	1				1
Due to brokers, net (pending trades with brokers)	(1)				(1)
Total pension plan assets	$1,011				$984

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
IPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$16	$—	$16	$—	$21	$—	$21	$—
Equity securities - U.S.	117	117	—	—	84	84	—	—
Equity securities - international	—	—	—	—	69	69	—	—
Global asset securities	24	24	—	—	21	21	—	—
Fixed income securities	87	21	66	—	62	26	36	—
Total assets in fair value hierarchy	244	$162	$82	$—	257	$200	$57	$—
Assets measured at net asset value	218				196
Total pension plan assets	$462				$453

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
WPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$16	$—	$16	$—	$20	$—	$20	$—
Equity securities - U.S.	114	114	—	—	81	81	—	—
Equity securities - international	—	—	—	—	67	67	—	—
Global asset securities	23	23	—	—	20	20	—	—
Fixed income securities	85	21	64	—	59	25	34	—
Total assets in fair value hierarchy	238	$158	$80	$—	247	$193	$54	$—
Assets measured at net asset value	212				189
Total pension plan assets	$450				$436

At December 31, the fair values of OPEB plan assets were as follows (in millions):

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
Alliant Energy	Value	1	2	3	Value	1	2	3
Cash and equivalents	$5	$—	$5	$—	$2	$—	$2	$—
Equity securities - U.S.	11	11	—	—	4	4	—	—
Equity securities - international	—	—	—	—	3	3	—	—
Global asset securities	1	1	—	—	—	—	—	—
Fixed income securities	60	58	2	—	72	71	1	—
Total assets in fair value hierarchy	77	$70	$7	$—	81	$78	$3	$—
Assets measured at net asset value	29				27
Total OPEB plan assets	$106				$108

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
IPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$1	$—	$1	$—	$1	$—	$1	$—
Equity securities - U.S.	8	8	—	—	—	—	—	—
Fixed income securities	42	42	—	—	51	51	—	—
Total assets in fair value hierarchy	51	$50	$1	$—	52	$51	$1	$—
Assets measured at net asset value	23				22
Total OPEB plan assets	$74				$74

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
WPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$1	$—	$1	$—	$—	$—	$—	$—
Equity securities - U.S.	1	1	—	—	—	—	—	—
Fixed income securities	15	15	—	—	18	18	—	—
Total OPEB plan assets	$17	$16	$1	$—	$18	$18	$—	$—

For the various defined benefit pension and OPEB plans, Alliant Energy common stock represented less than 1% of assets directly held in the plans at December 31, 2021 and 2020.

401(k) Savings Plans - A significant number of employees participate in defined contribution retirement plans (401(k) savings plans). Alliant Energy common stock directly held by participants represented 9% and 9% of total assets in the 401(k) savings plans at December 31, 2021 and 2020, respectively. Costs related to the 401(k) savings plans, which are partially based on the participants’ contributions and include allocated costs associated with Corporate Services employees for IPL and WPL, were as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
401(k) costs	$26	$25	$25	$13	$13	$13	$12	$12	$12

(b) Equity-based Compensation Plans - In 2020, Alliant Energy’s shareowners approved the 2020 OIP, which permits the grant of shares of Alliant Energy common stock, restricted stock, restricted stock units, performance shares, performance units, and other stock-based or cash-based awards to key employees. The 2020 OIP replaced the Amended and Restated 2010 OIP, which permitted similar grants. At December 31, 2021, performance shares and restricted stock units (performance- and time-vesting) were outstanding under the 2020 OIP and the Amended and Restated 2010 OIP, and 9 million shares of Alliant Energy common stock remained available for grants under the 2020 OIP. Alliant Energy satisfies share payouts related to equity awards through the issuance of new shares of its common stock. Alliant Energy also granted cash-based long-term awards, including performance units, restricted cash awards and restricted units, to certain key employees, under the DLIP. At December 31, 2021, no awards were outstanding under the DLIP. Nonvested awards generally do not have non-forfeitable rights to dividends or dividend equivalents when dividends are paid to common shareowners. A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Compensation expense	$14	$16	$26	$8	$9	$15	$6	$6	$10
Income tax benefits	4	4	7	2	2	4	2	2	3

As of December 31, 2021, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $5 million, $3 million and $2 million, respectively, which is expected to be recognized over a weighted average period of between one year and two years. Share-based compensation expense is recognized on a straight-line basis over the requisite service periods and is recorded in “Other operation and maintenance” in the income statements. As of December 31, 2021, 653,956 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

Performance Shares - Equity Awards - Payouts of 2021, 2020 and 2019 performance shares are contingent upon achievement over a three-year period of specified performance criteria, which currently is total shareowner return relative to an investor-owned utility peer group. Performance shares granted in 2021, 2020 and 2019 are to be paid out in shares of Alliant Energy common stock and are accounted for as equity awards. The fair value of each of these performance shares is based on the fair value of the underlying common stock on the grant date and the probability of satisfying the market condition contained in the agreement during a three-year performance period. The actual number of these performance shares that will be paid out upon vesting is dependent upon actual performance and may range from zero to 200% of the target number of shares. If minimum performance targets are not met during the performance period, these performance shares are forfeited. Compensation expense is recorded ratably over the performance period based on the fair value of the awards at the grant date. A summary of the 2021, 2020 and 2019 performance shares activity, with amounts representing the target number of awards, was as follows:

	2021		2020		2019
	Performance Shares - Equity	Weighted Average Grant Date Fair Value	Performance Shares - Equity	Weighted Average Grant Date Fair Value	Performance Shares - Equity	Weighted Average Grant Date Fair Value
Nonvested awards, January 1	129,156	$54.63	74,193	$47.44	—	$—
Granted	73,112	46.19	56,204	64.04	91,816	47.23
Forfeited	(5,839)	51.07	(1,241)	50.94	(17,623)	46.35
Nonvested awards, December 31	196,429	51.59	129,156	54.63	74,193	47.44

Performance Shares and Performance Units - Liability Awards - Payouts of performance shares granted prior to 2019 under the Amended and Restated 2010 OIP and performance units granted prior to 2019 under the DLIP to key employees were contingent upon achievement over three-year periods of specified performance criteria, which was total shareowner return relative to an investor-owned utility peer group. Performance shares granted prior to 2019 were able to be paid out in shares of Alliant Energy common stock, cash or a combination of cash and stock. Performance units granted prior to 2019 were paid out in cash. Alliant Energy assumed it would make future payouts of its performance shares granted prior to 2019 and performance units in cash; therefore, these performance shares and performance units were accounted for as liability awards. The fair value of each performance share and performance unit accounted for as a liability award was based on the closing market price of one share of Alliant Energy common stock at the end of the performance period. The actual payout for performance shares and performance units was dependent upon actual performance and may range from zero to 200% of the

target number of awards. Compensation expense for these performance shares and performance units was recorded ratably over the performance period based on the fair value of the awards at each reporting period. A summary of these performance shares and performance units activity, with amounts representing the target number of awards, was as follows:

	Performance Shares (granted prior to 2019)			Performance Units (granted prior to 2019)
	2021	2020	2019	2021	2020	2019
Nonvested awards, January 1	68,307	131,872	203,188	16,801	34,574	57,761
Vested	(68,307)	(63,565)	(66,322)	(16,801)	(16,661)	(20,131)
Forfeited	—	—	(4,994)	—	(1,112)	(3,056)
Nonvested awards, December 31	—	68,307	131,872	—	16,801	34,574

Vested Awards - Certain performance shares and performance units vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows:

	Performance Shares (granted prior to 2019)			Performance Units (granted prior to 2019)
	2021	2020	2019	2021	2020	2019
	2018 Grant	2017 Grant	2016 Grant	2018 Grant	2017 Grant	2016 Grant
Performance awards vested	68,307	63,565	66,322	16,801	16,661	20,131
Percentage of target number of performance awards	172.5%	155.0%	142.5%	172.5%	155.0%	142.5%
Aggregate payout value (in millions)	$7	$6	$4	$2	$2	$1
Payout - cash (in millions)	$5	$5	$4	$2	$2	$1
Payout - common stock shares issued	13,644	9,543	6,447	N/A	N/A	N/A

Restricted Stock Units - Equity Awards - Payouts of 2021, 2020 and 2019 restricted stock units are based on the expiration of a three-year time-vesting period. Restricted stock units granted in 2021, 2020 and 2019 are to be paid out in shares of Alliant Energy common stock and are accounted for as equity awards. The fair value of each of these restricted stock units is based on the closing market price of one share of Alliant Energy common stock on the grant date of the award. Compensation expense is recorded ratably over the performance period based on the fair value of the awards on the grant date. A summary of the 2021, 2020 and 2019 restricted stock units activity was as follows:

	2021		2020		2019
	Restricted Stock Units - Equity	Weighted Average Grant Date Fair Value	Restricted Stock Units - Equity	Weighted Average Grant Date Fair Value	Restricted Stock Units - Equity	Weighted Average Grant Date Fair Value
Nonvested units, January 1	146,549	$51.54	89,281	$46.04	—	$—
Granted	80,152	48.65	61,056	59.42	105,348	45.98
Forfeited	(8,882)	49.84	(3,788)	49.01	(16,067)	45.63
Nonvested units, December 31	217,819	50.54	146,549	51.54	89,281	46.04

Restricted Stock Units - Liability Awards - Payouts of restricted stock units granted prior to 2019 were based on the expiration of a three-year time-vesting period and were able to be paid out in shares of Alliant Energy common stock, cash or a combination of cash and stock. Alliant Energy assumed it would make future payouts of its restricted stock units granted prior to 2019 in cash; therefore, restricted stock units granted prior to 2019 were accounted for as liability awards. The fair value of each restricted stock unit granted prior to 2019 was based on the closing market price of one share of Alliant Energy common stock at the end of the time-vesting period. Compensation expense was recorded ratably over the performance period based on the fair value of the awards at each reporting period. A summary of the restricted stock units granted prior to 2019 activity was as follows:

	2021	2020	2019
Nonvested units, January 1	58,550	113,033	174,163
Vested	(58,550)	(54,483)	(56,849)
Forfeited	—	—	(4,281)
Nonvested units, December 31	—	58,550	113,033

Performance Restricted Stock Units - Equity Awards - Payouts of performance restricted stock units are based upon achievement of certain performance targets during a three-year performance period, which currently includes specified growth of consolidated net income from continuing operations. The actual number of units that will be paid out upon vesting is dependent upon actual performance and may range from zero to 200% of the target number of units. If minimum performance targets are not met during the performance period, these units are forfeited. Performance restricted stock units are to be paid out in shares and are accounted for as equity awards. The fair value of each performance restricted stock unit is based on the closing market price of one share of Alliant Energy common stock on the grant date of the award. Compensation expense is recorded ratably over the performance period based on a probability assessment of payouts for the awards at each reporting period. A summary of the performance restricted stock units activity, with amounts representing the target number of units, was as follows:

	2021		2020		2019
	Units	Weighted Average Grant Date Fair Value	Units	Weighted Average Grant Date Fair Value	Units	Weighted Average Grant Date Fair Value
Nonvested units, January 1	197,463	$47.31	206,065	$41.50	203,188	$37.23
Granted	73,112	48.66	56,204	59.37	91,816	46.10
Vested	(68,307)	38.60	(63,565)	39.12	(66,322)	33.93
Forfeited	(5,839)	50.46	(1,241)	49.25	(22,617)	44.00
Nonvested units, December 31	196,429	50.74	197,463	47.31	206,065	41.50

WPL [Member]

Benefit Plans

BENEFIT PLANS(a) Pension and Other Postretirement Benefits Plans - Retirement benefits are provided to substantially all employees through various qualified and non-qualified non-contributory defined benefit pension plans (currently closed to new hires), and/or through defined contribution plans (including 401(k) savings plans). Benefits of the non-contributory defined benefit pension plans are based on the plan participant’s years of service, age and compensation. Benefits of the defined contribution plans are based on the plan participant’s years of service, age, compensation and contributions. Certain defined benefit postretirement health care and life benefits are provided to eligible retirees. In general, the retiree health care plans consist of fixed benefit subsidy structures and the retiree life insurance plans are non-contributory.

IPL and WPL account for their participation in Alliant Energy and Corporate Services sponsored plans as multiple-employer plans. For IPL and WPL, amounts below represent the amounts for their plan participants covered under plans they sponsor, as well as amounts directly assigned to them related to certain participants in the Alliant Energy and Corporate Services sponsored plans.

Assumptions - The assumptions for defined benefit pension and OPEB plans at the measurement date of December 31 were as follows:

	Defined Benefit Pension Plans									OPEB Plans
Alliant Energy	2021			2020			2019			2021	2020	2019
Discount rate for benefit obligations	2.91%			2.57%			3.48%			2.81%	2.31%	3.40%
Discount rate for net periodic cost	2.57%			3.48%			4.34%			2.31%	3.40%	4.24%
Expected rate of return on plan assets	7.10%			7.10%			7.60%			4.80%	4.50%	5.44%
Interest crediting rate for Alliant Energy Cash Balance Pension Plan	4.18%			4.76%			5.52%			N/A	N/A	N/A
Rate of compensation increase	3.30%	-	4.50%	3.65%	-	4.50%	3.65%	-	4.50%	N/A	N/A	N/A

	Qualified Defined Benefit Pension Plan			OPEB Plans
IPL	2021	2020	2019	2021	2020	2019
Discount rate for benefit obligations	2.94%	2.61%	3.51%	2.80%	2.28%	3.39%
Discount rate for net periodic cost	2.61%	3.51%	4.35%	2.28%	3.39%	4.23%
Expected rate of return on plan assets	7.10%	7.10%	7.60%	5.10%	4.50%	5.60%
Rate of compensation increase	3.30%	3.65%	3.65%	N/A	N/A	N/A

	Qualified Defined Benefit Pension Plan			OPEB Plans
WPL	2021	2020	2019	2021	2020	2019
Discount rate for benefit obligations	2.94%	2.64%	3.50%	2.79%	2.27%	3.39%
Discount rate for net periodic cost	2.64%	3.50%	4.35%	2.27%	3.39%	4.23%
Expected rate of return on plan assets	7.10%	7.10%	7.60%	4.02%	3.28%	3.81%
Rate of compensation increase	3.30%	3.65%	3.65%	N/A	N/A	N/A

Expected rate of return on plan assets - The expected rate of return on plan assets is based on projected asset class returns using target allocations. A forward-looking building blocks approach is used, and historical returns, survey information and capital market information are analyzed to support the expected rate of return on plan assets assumption. Refer to “Investment Strategy for Plan Assets” below for additional information related to investment strategy and mix of assets for the pension and OPEB plans.

Life Expectancy - The life expectancy assumption is used in determining the benefit obligation and net periodic benefit cost for defined benefit pension and OPEB plans. This assumption utilizes base mortality tables that were released in 2019 by the Society of Actuaries and mortality projection tables that were released in 2020 by the Society of Actuaries.

Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans are included below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements.

Alliant Energy	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$11	$11	$10	$4	$3	$3
Interest cost	34	43	50	5	7	9
Expected return on plan assets (a)	(69)	(70)	(60)	(5)	(5)	(5)
Amortization of prior service credit (b)	—	—	(1)	—	—	—
Amortization of actuarial loss (c)	39	34	36	5	3	3
Settlement losses (d)	—	12	—	—	—	—
	$15	$30	$35	$9	$8	$10

IPL	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$7	$7	$6	$1	$1	$1
Interest cost	16	20	23	2	3	3
Expected return on plan assets (a)	(32)	(33)	(28)	(3)	(4)	(4)
Amortization of actuarial loss (c)	17	15	15	2	1	2
Settlement losses (d)	—	7	—	—	—	—
	$8	$16	$16	$2	$1	$2

WPL	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$4	$4	$3	$1	$2	$1
Interest cost	15	19	21	2	3	3
Expected return on plan assets (a)	(31)	(31)	(26)	—	(1)	(1)
Amortization of prior service credit (b)	—	—	—	—	(1)	—
Amortization of actuarial loss (c)	19	16	18	2	2	2
	$7	$8	$16	$5	$5	$5

(a)The expected return on plan assets is based on the expected rate of return on plan assets and the fair value approach to the market-related value of plan assets.

(b)Unrecognized prior service credits for the OPEB plans are amortized over the average future service period to full eligibility of the participants of each plan.

(c)Unrecognized net actuarial gains or losses in excess of 10% of the greater of the plans’ benefit obligations or assets are amortized over the average future service lives of plan participants, except for the Alliant Energy Cash Balance Pension Plan where gains or losses outside the 10% threshold are amortized over the time period the participants are expected to receive benefits.

(d)Settlement losses related to payments made to retired executives of Alliant Energy and lump sum payments related to IPL’s qualified defined benefit pension plan.

Benefit Plan Assets and Obligations - A reconciliation of the funded status of qualified and non-qualified defined benefit pension and OPEB plans to the amounts recognized on the balance sheets at December 31 was as follows (in millions):

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$1,351	$1,280	$227	$214
Service cost	11	11	4	3
Interest cost	34	43	5	7
Plan participants’ contributions	—	—	5	4
Actuarial (gain) loss	(46)	132	(12)	18
Gross benefits paid	(99)	(115)	(19)	(19)
Net benefit obligation at December 31	1,251	1,351	210	227
Change in plan assets:
Fair value of plan assets at January 1	984	931	108	105
Actual return on plan assets	87	108	4	11
Employer contributions	39	60	8	7
Plan participants’ contributions	—	—	5	4
Gross benefits paid	(99)	(115)	(19)	(19)
Fair value of plan assets at December 31	1,011	984	106	108
Under funded status at December 31	($240)	($367)	($104)	($119)

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$13	$8
Current liabilities	(2)	(2)	(8)	(8)
Pension and other benefit obligations	(238)	(365)	(109)	(119)
Net amounts recognized at December 31	($240)	($367)	($104)	($119)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$429	$533	$38	$54
Prior service credit	(4)	(5)	(1)	(1)
	$425	$528	$37	$53

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$615	$581	$91	$86
Service cost	7	7	1	1
Interest cost	16	20	2	3
Plan participants’ contributions	—	—	2	1
Actuarial (gain) loss	(23)	60	(4)	8
Gross benefits paid	(48)	(53)	(8)	(8)
Net benefit obligation at December 31	567	615	84	91
Change in plan assets:
Fair value of plan assets at January 1	453	436	74	72
Actual return on plan assets	40	51	4	7
Employer contributions	17	19	2	2
Plan participants’ contributions	—	—	2	1
Gross benefits paid	(48)	(53)	(8)	(8)
Fair value of plan assets at December 31	462	453	74	74
Under funded status at December 31	($105)	($162)	($10)	($17)

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$10	$4
Current liabilities	—	(1)	(2)	(2)
Pension and other benefit obligations	(105)	(161)	(18)	(19)
Net amounts recognized at December 31	($105)	($162)	($10)	($17)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$180	$228	$13	$20
Prior service credit	(1)	(1)	—	—
	$179	$227	$13	$20

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$588	$550	$89	$85
Service cost	4	4	1	2
Interest cost	15	19	2	3
Plan participants’ contributions	—	—	2	2
Actuarial (gain) loss	(18)	55	(5)	5
Gross benefits paid	(43)	(40)	(8)	(8)
Net benefit obligation at December 31	546	588	81	89
Change in plan assets:
Fair value of plan assets at January 1	436	406	18	17
Actual return on plan assets	39	48	—	2
Employer contributions	18	22	5	5
Plan participants’ contributions	—	—	2	2
Gross benefits paid	(43)	(40)	(8)	(8)
Fair value of plan assets at December 31	450	436	17	18
Under funded status at December 31	($96)	($152)	($64)	($71)

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$3	$3
Current liabilities	—	—	(6)	(6)
Pension and other benefit obligations	(96)	(152)	(61)	(68)
Net amounts recognized at December 31	($96)	($152)	($64)	($71)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$188	$233	$18	$25
Prior service credit	(1)	(1)	(1)	(1)
	$187	$232	$17	$24

Actuarial gains related to benefit obligations in 2021 for defined benefit pension and OPEB plans were primarily due to increases in the discount rates. Actuarial losses related to benefit obligations in 2020 for defined benefit pension and OPEB plans were primarily due to decreases in the discount rates, partially offset by the impact of updated mortality projection tables.

Accumulated benefit obligations, aggregate amounts applicable to defined benefit pension and OPEB plans with accumulated benefit obligations in excess of plan assets, as well as defined benefit pension plans with projected benefit obligations in excess of plan assets as of the December 31 measurement date are as follows (in millions):

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Accumulated benefit obligations	$1,214	$1,305	$210	$227
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	1,214	1,305	210	227
Fair value of plan assets	1,011	984	106	108
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	1,251	1,351	N/A	N/A
Fair value of plan assets	1,011	984	N/A	N/A

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Accumulated benefit obligations	$546	$589	$84	$91
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	546	589	84	91
Fair value of plan assets	462	453	74	74
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	567	615	N/A	N/A
Fair value of plan assets	462	453	N/A	N/A

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Accumulated benefit obligations	$532	$573	$81	$89
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	532	573	81	89
Fair value of plan assets	450	436	17	18
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	546	588	N/A	N/A
Fair value of plan assets	450	436	N/A	N/A

In addition to the amounts recognized in regulatory assets in the above tables for IPL and WPL, regulatory assets were recognized for amounts associated with Corporate Services employees participating in other Alliant Energy sponsored benefit plans that were allocated to IPL and WPL at December 31 as follows (in millions):

	IPL		WPL
	2021	2020	2021	2020
Regulatory assets	$35	$44	$30	$34

Estimated Future Employer Contributions and Benefit Payments - Estimated funding for the qualified and non-qualified defined benefit pension and OPEB plans for 2022 is as follows (in millions):

	Alliant Energy	IPL	WPL
Defined benefit pension plans (a)	$2	$—	$—
OPEB plans	8	2	6

(a)Alliant Energy sponsors several non-qualified defined benefit pension plans that cover certain current and former key employees of IPL and WPL. Alliant Energy allocates pension costs to IPL and WPL for these plans. In addition, IPL and WPL amounts reflect funding for their non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.

Expected benefit payments for the qualified and non-qualified defined benefit plans, which reflect expected future service, as appropriate, are as follows (in millions):

Alliant Energy	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$85	$83	$82	$82	$83	$387
OPEB	18	17	17	17	16	71
	$103	$100	$99	$99	$99	$458

IPL	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$41	$40	$39	$39	$38	$174
OPEB	7	7	7	7	7	28
	$48	$47	$46	$46	$45	$202

WPL	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$37	$36	$35	$35	$34	$163
OPEB	7	7	7	7	6	27
	$44	$43	$42	$42	$40	$190

Investment Strategy for Plan Assets - Investment strategies for defined benefit pension and OPEB plan assets combine preservation of principal and prudent risk-taking to protect the integrity of plan assets, in order to meet the obligations to plan participants while minimizing benefit costs over the long term. Investment risk of plan assets is mitigated through diversification, including U.S. and international equity, fixed income and global asset strategies. Global asset strategies may include investments in global equity, global debt and currencies.

Defined Benefit Pension Plan Assets - The asset mix of defined benefit pension plans is governed by allocation targets. The asset allocation is monitored regularly, and appropriate steps are taken as needed to rebalance the assets within the prescribed ranges. An overlay management service is also used to help maintain target allocations and meet liquidity needs. The overlay manager is authorized to use derivative financial instruments to facilitate this service. For separately managed accounts, prohibited investments include, but are not limited to, direct ownership of real estate, oil and gas limited partnerships, securities of the managers’ firms or affiliate firms, and Alliant Energy securities. At December 31, 2021, the current target ranges and actual allocations for the defined benefit pension plan assets were as follows:

	Target Range			Actual
	Allocation			Allocation
Cash and equivalents	0%	-	5%	3%
Equity securities - U.S.	14%	-	54%	34%
Equity securities - international	11%	-	31%	21%
Global asset securities	5%	-	15%	9%
Fixed income securities	25%	-	45%	33%

Other Postretirement Benefits Plan Assets - OPEB plan assets are comprised of specific assets within certain defined benefit pension plans (401(h) assets) as well as assets held in VEBA trusts. The investment strategy of the Corporate Services 401(h) assets mirrors those of the defined benefit pension plans, which are discussed above. For VEBA trusts with assets greater than $5 million and the WPL 401(h) assets, the mix among asset classes is governed by allocation targets. The asset allocation is monitored regularly, and appropriate steps are taken as needed to rebalance the assets within the prescribed ranges. At December 31, 2021, the current target ranges and actual allocations for VEBA trusts with assets greater than $5 million and the WPL 401(h) assets were as follows:

	Target Range			Actual
	Allocation			Allocation
Cash and equivalents	0%	-	5%	1%
Equity securities - U.S.	0%	-	55%	35%
Fixed income securities	40%	-	100%	64%

Fair Value Measurements - Fair value measurement accounting establishes three levels of fair value hierarchy that prioritize the inputs to valuation techniques used to measure fair value. Refer to Note 16 for discussion of levels within the fair value hierarchy. Level 1 items include investments in securities held in registered investment companies and directly held equity securities, which are valued at the closing price reported in the active market in which the securities are traded. Level 2 items include fixed income securities consisting of corporate and government bonds, which are valued at the closing price reported in the active market for similar assets in which the individual securities are traded or based on yields currently available on comparable securities of issuers with similar credit ratings. Certain investments that are measured at fair value using the net asset value practical expedient have not been classified in the fair value hierarchy. These fair value amounts are included below to reconcile the fair value hierarchy to the respective total plan assets.

At December 31, the fair values of qualified and non-qualified defined benefit pension plan assets were as follows (in millions):

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
Alliant Energy	Value	1	2	3	Value	1	2	3
Cash and equivalents	$35	$—	$35	$—	$46	$—	$46	$—
Equity securities - U.S.	256	256	—	—	182	182	—	—
Equity securities - international	—	—	—	—	151	151	—	—
Global asset securities	52	52	—	—	45	45	—	—
Fixed income securities	191	47	144	—	134	56	78	—
Total assets in fair value hierarchy	534	$355	$179	$—	558	$434	$124	$—
Assets measured at net asset value	477				426
Accrued investment income	1				1
Due to brokers, net (pending trades with brokers)	(1)				(1)
Total pension plan assets	$1,011				$984

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
IPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$16	$—	$16	$—	$21	$—	$21	$—
Equity securities - U.S.	117	117	—	—	84	84	—	—
Equity securities - international	—	—	—	—	69	69	—	—
Global asset securities	24	24	—	—	21	21	—	—
Fixed income securities	87	21	66	—	62	26	36	—
Total assets in fair value hierarchy	244	$162	$82	$—	257	$200	$57	$—
Assets measured at net asset value	218				196
Total pension plan assets	$462				$453

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
WPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$16	$—	$16	$—	$20	$—	$20	$—
Equity securities - U.S.	114	114	—	—	81	81	—	—
Equity securities - international	—	—	—	—	67	67	—	—
Global asset securities	23	23	—	—	20	20	—	—
Fixed income securities	85	21	64	—	59	25	34	—
Total assets in fair value hierarchy	238	$158	$80	$—	247	$193	$54	$—
Assets measured at net asset value	212				189
Total pension plan assets	$450				$436

At December 31, the fair values of OPEB plan assets were as follows (in millions):

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
Alliant Energy	Value	1	2	3	Value	1	2	3
Cash and equivalents	$5	$—	$5	$—	$2	$—	$2	$—
Equity securities - U.S.	11	11	—	—	4	4	—	—
Equity securities - international	—	—	—	—	3	3	—	—
Global asset securities	1	1	—	—	—	—	—	—
Fixed income securities	60	58	2	—	72	71	1	—
Total assets in fair value hierarchy	77	$70	$7	$—	81	$78	$3	$—
Assets measured at net asset value	29				27
Total OPEB plan assets	$106				$108

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
IPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$1	$—	$1	$—	$1	$—	$1	$—
Equity securities - U.S.	8	8	—	—	—	—	—	—
Fixed income securities	42	42	—	—	51	51	—	—
Total assets in fair value hierarchy	51	$50	$1	$—	52	$51	$1	$—
Assets measured at net asset value	23				22
Total OPEB plan assets	$74				$74

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
WPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$1	$—	$1	$—	$—	$—	$—	$—
Equity securities - U.S.	1	1	—	—	—	—	—	—
Fixed income securities	15	15	—	—	18	18	—	—
Total OPEB plan assets	$17	$16	$1	$—	$18	$18	$—	$—

For the various defined benefit pension and OPEB plans, Alliant Energy common stock represented less than 1% of assets directly held in the plans at December 31, 2021 and 2020.

401(k) Savings Plans - A significant number of employees participate in defined contribution retirement plans (401(k) savings plans). Alliant Energy common stock directly held by participants represented 9% and 9% of total assets in the 401(k) savings plans at December 31, 2021 and 2020, respectively. Costs related to the 401(k) savings plans, which are partially based on the participants’ contributions and include allocated costs associated with Corporate Services employees for IPL and WPL, were as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
401(k) costs	$26	$25	$25	$13	$13	$13	$12	$12	$12

(b) Equity-based Compensation Plans - In 2020, Alliant Energy’s shareowners approved the 2020 OIP, which permits the grant of shares of Alliant Energy common stock, restricted stock, restricted stock units, performance shares, performance units, and other stock-based or cash-based awards to key employees. The 2020 OIP replaced the Amended and Restated 2010 OIP, which permitted similar grants. At December 31, 2021, performance shares and restricted stock units (performance- and time-vesting) were outstanding under the 2020 OIP and the Amended and Restated 2010 OIP, and 9 million shares of Alliant Energy common stock remained available for grants under the 2020 OIP. Alliant Energy satisfies share payouts related to equity awards through the issuance of new shares of its common stock. Alliant Energy also granted cash-based long-term awards, including performance units, restricted cash awards and restricted units, to certain key employees, under the DLIP. At December 31, 2021, no awards were outstanding under the DLIP. Nonvested awards generally do not have non-forfeitable rights to dividends or dividend equivalents when dividends are paid to common shareowners. A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Compensation expense	$14	$16	$26	$8	$9	$15	$6	$6	$10
Income tax benefits	4	4	7	2	2	4	2	2	3

As of December 31, 2021, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $5 million, $3 million and $2 million, respectively, which is expected to be recognized over a weighted average period of between one year and two years. Share-based compensation expense is recognized on a straight-line basis over the requisite service periods and is recorded in “Other operation and maintenance” in the income statements. As of December 31, 2021, 653,956 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

Performance Shares - Equity Awards - Payouts of 2021, 2020 and 2019 performance shares are contingent upon achievement over a three-year period of specified performance criteria, which currently is total shareowner return relative to an investor-owned utility peer group. Performance shares granted in 2021, 2020 and 2019 are to be paid out in shares of Alliant Energy common stock and are accounted for as equity awards. The fair value of each of these performance shares is based on the fair value of the underlying common stock on the grant date and the probability of satisfying the market condition contained in the agreement during a three-year performance period. The actual number of these performance shares that will be paid out upon vesting is dependent upon actual performance and may range from zero to 200% of the target number of shares. If minimum performance targets are not met during the performance period, these performance shares are forfeited. Compensation expense is recorded ratably over the performance period based on the fair value of the awards at the grant date. A summary of the 2021, 2020 and 2019 performance shares activity, with amounts representing the target number of awards, was as follows:

	2021		2020		2019
	Performance Shares - Equity	Weighted Average Grant Date Fair Value	Performance Shares - Equity	Weighted Average Grant Date Fair Value	Performance Shares - Equity	Weighted Average Grant Date Fair Value
Nonvested awards, January 1	129,156	$54.63	74,193	$47.44	—	$—
Granted	73,112	46.19	56,204	64.04	91,816	47.23
Forfeited	(5,839)	51.07	(1,241)	50.94	(17,623)	46.35
Nonvested awards, December 31	196,429	51.59	129,156	54.63	74,193	47.44

Performance Shares and Performance Units - Liability Awards - Payouts of performance shares granted prior to 2019 under the Amended and Restated 2010 OIP and performance units granted prior to 2019 under the DLIP to key employees were contingent upon achievement over three-year periods of specified performance criteria, which was total shareowner return relative to an investor-owned utility peer group. Performance shares granted prior to 2019 were able to be paid out in shares of Alliant Energy common stock, cash or a combination of cash and stock. Performance units granted prior to 2019 were paid out in cash. Alliant Energy assumed it would make future payouts of its performance shares granted prior to 2019 and performance units in cash; therefore, these performance shares and performance units were accounted for as liability awards. The fair value of each performance share and performance unit accounted for as a liability award was based on the closing market price of one share of Alliant Energy common stock at the end of the performance period. The actual payout for performance shares and performance units was dependent upon actual performance and may range from zero to 200% of the

target number of awards. Compensation expense for these performance shares and performance units was recorded ratably over the performance period based on the fair value of the awards at each reporting period. A summary of these performance shares and performance units activity, with amounts representing the target number of awards, was as follows:

	Performance Shares (granted prior to 2019)			Performance Units (granted prior to 2019)
	2021	2020	2019	2021	2020	2019
Nonvested awards, January 1	68,307	131,872	203,188	16,801	34,574	57,761
Vested	(68,307)	(63,565)	(66,322)	(16,801)	(16,661)	(20,131)
Forfeited	—	—	(4,994)	—	(1,112)	(3,056)
Nonvested awards, December 31	—	68,307	131,872	—	16,801	34,574

Vested Awards - Certain performance shares and performance units vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows:

	Performance Shares (granted prior to 2019)			Performance Units (granted prior to 2019)
	2021	2020	2019	2021	2020	2019
	2018 Grant	2017 Grant	2016 Grant	2018 Grant	2017 Grant	2016 Grant
Performance awards vested	68,307	63,565	66,322	16,801	16,661	20,131
Percentage of target number of performance awards	172.5%	155.0%	142.5%	172.5%	155.0%	142.5%
Aggregate payout value (in millions)	$7	$6	$4	$2	$2	$1
Payout - cash (in millions)	$5	$5	$4	$2	$2	$1
Payout - common stock shares issued	13,644	9,543	6,447	N/A	N/A	N/A

Restricted Stock Units - Equity Awards - Payouts of 2021, 2020 and 2019 restricted stock units are based on the expiration of a three-year time-vesting period. Restricted stock units granted in 2021, 2020 and 2019 are to be paid out in shares of Alliant Energy common stock and are accounted for as equity awards. The fair value of each of these restricted stock units is based on the closing market price of one share of Alliant Energy common stock on the grant date of the award. Compensation expense is recorded ratably over the performance period based on the fair value of the awards on the grant date. A summary of the 2021, 2020 and 2019 restricted stock units activity was as follows:

	2021		2020		2019
	Restricted Stock Units - Equity	Weighted Average Grant Date Fair Value	Restricted Stock Units - Equity	Weighted Average Grant Date Fair Value	Restricted Stock Units - Equity	Weighted Average Grant Date Fair Value
Nonvested units, January 1	146,549	$51.54	89,281	$46.04	—	$—
Granted	80,152	48.65	61,056	59.42	105,348	45.98
Forfeited	(8,882)	49.84	(3,788)	49.01	(16,067)	45.63
Nonvested units, December 31	217,819	50.54	146,549	51.54	89,281	46.04

Restricted Stock Units - Liability Awards - Payouts of restricted stock units granted prior to 2019 were based on the expiration of a three-year time-vesting period and were able to be paid out in shares of Alliant Energy common stock, cash or a combination of cash and stock. Alliant Energy assumed it would make future payouts of its restricted stock units granted prior to 2019 in cash; therefore, restricted stock units granted prior to 2019 were accounted for as liability awards. The fair value of each restricted stock unit granted prior to 2019 was based on the closing market price of one share of Alliant Energy common stock at the end of the time-vesting period. Compensation expense was recorded ratably over the performance period based on the fair value of the awards at each reporting period. A summary of the restricted stock units granted prior to 2019 activity was as follows:

	2021	2020	2019
Nonvested units, January 1	58,550	113,033	174,163
Vested	(58,550)	(54,483)	(56,849)
Forfeited	—	—	(4,281)
Nonvested units, December 31	—	58,550	113,033

Performance Restricted Stock Units - Equity Awards - Payouts of performance restricted stock units are based upon achievement of certain performance targets during a three-year performance period, which currently includes specified growth of consolidated net income from continuing operations. The actual number of units that will be paid out upon vesting is dependent upon actual performance and may range from zero to 200% of the target number of units. If minimum performance targets are not met during the performance period, these units are forfeited. Performance restricted stock units are to be paid out in shares and are accounted for as equity awards. The fair value of each performance restricted stock unit is based on the closing market price of one share of Alliant Energy common stock on the grant date of the award. Compensation expense is recorded ratably over the performance period based on a probability assessment of payouts for the awards at each reporting period. A summary of the performance restricted stock units activity, with amounts representing the target number of units, was as follows:

	2021		2020		2019
	Units	Weighted Average Grant Date Fair Value	Units	Weighted Average Grant Date Fair Value	Units	Weighted Average Grant Date Fair Value
Nonvested units, January 1	197,463	$47.31	206,065	$41.50	203,188	$37.23
Granted	73,112	48.66	56,204	59.37	91,816	46.10
Vested	(68,307)	38.60	(63,565)	39.12	(66,322)	33.93
Forfeited	(5,839)	50.46	(1,241)	49.25	(22,617)	44.00
Nonvested units, December 31	196,429	50.74	197,463	47.31	206,065	41.50

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Asset Retirement Obligations

12 Months Ended

Dec. 31, 2021

Schedule of Asset Retirement Obligations [Line Items]

Asset Retirement Obligations (AROs)

ASSET RETIREMENT OBLIGATIONS

Recognized AROs relate to legal obligations for the removal, closure or dismantlement of several assets including, but not limited to, wind farms, ash ponds, active ash landfills, coal yards, above ground storage tanks and solar generation. Recognized AROs also include legal obligations for the management and final disposition of asbestos and polychlorinated biphenyls. AROs are recorded in “Other current liabilities” and “Other liabilities” on the balance sheets. Refer to Note 2 for information regarding regulatory assets related to AROs. A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Balance, January 1	$251	$196	$177	$134	$74	$62
Revisions in estimated cash flows	50	13	44	9	6	4
Liabilities settled	(17)	(13)	(13)	(9)	(4)	(4)
Liabilities incurred	3	48	—	38	3	10
Accretion expense	7	7	5	5	2	2
Balance, December 31	$294	$251	$213	$177	$81	$74

IPL [Member]

Schedule of Asset Retirement Obligations [Line Items]

Asset Retirement Obligations (AROs)

ASSET RETIREMENT OBLIGATIONS

Recognized AROs relate to legal obligations for the removal, closure or dismantlement of several assets including, but not limited to, wind farms, ash ponds, active ash landfills, coal yards, above ground storage tanks and solar generation. Recognized AROs also include legal obligations for the management and final disposition of asbestos and polychlorinated biphenyls. AROs are recorded in “Other current liabilities” and “Other liabilities” on the balance sheets. Refer to Note 2 for information regarding regulatory assets related to AROs. A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Balance, January 1	$251	$196	$177	$134	$74	$62
Revisions in estimated cash flows	50	13	44	9	6	4
Liabilities settled	(17)	(13)	(13)	(9)	(4)	(4)
Liabilities incurred	3	48	—	38	3	10
Accretion expense	7	7	5	5	2	2
Balance, December 31	$294	$251	$213	$177	$81	$74

WPL [Member]

Schedule of Asset Retirement Obligations [Line Items]

Asset Retirement Obligations (AROs)

ASSET RETIREMENT OBLIGATIONS

Recognized AROs relate to legal obligations for the removal, closure or dismantlement of several assets including, but not limited to, wind farms, ash ponds, active ash landfills, coal yards, above ground storage tanks and solar generation. Recognized AROs also include legal obligations for the management and final disposition of asbestos and polychlorinated biphenyls. AROs are recorded in “Other current liabilities” and “Other liabilities” on the balance sheets. Refer to Note 2 for information regarding regulatory assets related to AROs. A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Balance, January 1	$251	$196	$177	$134	$74	$62
Revisions in estimated cash flows	50	13	44	9	6	4
Liabilities settled	(17)	(13)	(13)	(9)	(4)	(4)
Liabilities incurred	3	48	—	38	3	10
Accretion expense	7	7	5	5	2	2
Balance, December 31	$294	$251	$213	$177	$81	$74

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Derivative Instruments

12 Months Ended

Dec. 31, 2021

Derivative [Line Items]

Derivative Instruments

DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Purpose - Derivative instruments are used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices, transmission congestion costs and rail transportation costs. Risk policies are maintained that govern the use of such derivative instruments. Derivative instruments were not designated as hedging instruments and included the following:

Risk management purpose	Type of instrument
Mitigate pricing volatility for:
Fuel used to supply natural gas-fired EGUs	Natural gas swap, options and physical forward contracts (IPL and WPL)
Natural gas supplied to retail customers	Natural gas swap, options and physical forward contracts (IPL and WPL)
Fuel used at coal-fired EGUs	Coal physical forward contracts (IPL and WPL)
Optimize the value of natural gas pipeline capacity	Natural gas physical forward contracts (IPL and WPL)
	Natural gas swap contracts (IPL)
Manage transmission congestion costs	FTRs (IPL and WPL)
Manage rail transportation costs	Diesel fuel swap contracts (WPL)

Notional Amounts - As of December 31, 2021, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):

	FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	9,135	2022	191,670	2022-2030	3,193	2022-2023	3,024	2022
IPL	2,647	2022	100,560	2022-2030	1,270	2022-2023	—	—
WPL	6,488	2022	91,110	2022-2030	1,923	2022-2023	3,024	2022

Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheet as assets or liabilities. At December 31, the fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Current derivative assets	$113	$24	$48	$20	$65	$4
Non-current derivative assets	63	10	36	9	27	1
Current derivative liabilities	8	9	4	3	4	6
Non-current derivative liabilities	1	16	—	9	1	7

In 2021, Alliant Energy’s, IPL’s and WPL’s derivative assets increased and derivative liabilities decreased primarily as a result of higher natural gas prices. Based on IPL’s and WPL’s natural gas cost recovery mechanisms, this resulted in corresponding decreases in derivative regulatory assets and increases in derivative regulatory liabilities on the balance sheets.

Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At December 31, 2021 and 2020, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered.

Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at December 31, 2021 and 2020. Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement.

IPL [Member]

Derivative [Line Items]

Derivative Instruments

DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Purpose - Derivative instruments are used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices, transmission congestion costs and rail transportation costs. Risk policies are maintained that govern the use of such derivative instruments. Derivative instruments were not designated as hedging instruments and included the following:

Risk management purpose	Type of instrument
Mitigate pricing volatility for:
Fuel used to supply natural gas-fired EGUs	Natural gas swap, options and physical forward contracts (IPL and WPL)
Natural gas supplied to retail customers	Natural gas swap, options and physical forward contracts (IPL and WPL)
Fuel used at coal-fired EGUs	Coal physical forward contracts (IPL and WPL)
Optimize the value of natural gas pipeline capacity	Natural gas physical forward contracts (IPL and WPL)
	Natural gas swap contracts (IPL)
Manage transmission congestion costs	FTRs (IPL and WPL)
Manage rail transportation costs	Diesel fuel swap contracts (WPL)

Notional Amounts - As of December 31, 2021, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):

	FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	9,135	2022	191,670	2022-2030	3,193	2022-2023	3,024	2022
IPL	2,647	2022	100,560	2022-2030	1,270	2022-2023	—	—
WPL	6,488	2022	91,110	2022-2030	1,923	2022-2023	3,024	2022

Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheet as assets or liabilities. At December 31, the fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Current derivative assets	$113	$24	$48	$20	$65	$4
Non-current derivative assets	63	10	36	9	27	1
Current derivative liabilities	8	9	4	3	4	6
Non-current derivative liabilities	1	16	—	9	1	7

In 2021, Alliant Energy’s, IPL’s and WPL’s derivative assets increased and derivative liabilities decreased primarily as a result of higher natural gas prices. Based on IPL’s and WPL’s natural gas cost recovery mechanisms, this resulted in corresponding decreases in derivative regulatory assets and increases in derivative regulatory liabilities on the balance sheets.

Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At December 31, 2021 and 2020, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered.

Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at December 31, 2021 and 2020. Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement.

WPL [Member]

Derivative [Line Items]

Derivative Instruments

DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Purpose - Derivative instruments are used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices, transmission congestion costs and rail transportation costs. Risk policies are maintained that govern the use of such derivative instruments. Derivative instruments were not designated as hedging instruments and included the following:

Risk management purpose	Type of instrument
Mitigate pricing volatility for:
Fuel used to supply natural gas-fired EGUs	Natural gas swap, options and physical forward contracts (IPL and WPL)
Natural gas supplied to retail customers	Natural gas swap, options and physical forward contracts (IPL and WPL)
Fuel used at coal-fired EGUs	Coal physical forward contracts (IPL and WPL)
Optimize the value of natural gas pipeline capacity	Natural gas physical forward contracts (IPL and WPL)
	Natural gas swap contracts (IPL)
Manage transmission congestion costs	FTRs (IPL and WPL)
Manage rail transportation costs	Diesel fuel swap contracts (WPL)

Notional Amounts - As of December 31, 2021, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):

	FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	9,135	2022	191,670	2022-2030	3,193	2022-2023	3,024	2022
IPL	2,647	2022	100,560	2022-2030	1,270	2022-2023	—	—
WPL	6,488	2022	91,110	2022-2030	1,923	2022-2023	3,024	2022

Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheet as assets or liabilities. At December 31, the fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Current derivative assets	$113	$24	$48	$20	$65	$4
Non-current derivative assets	63	10	36	9	27	1
Current derivative liabilities	8	9	4	3	4	6
Non-current derivative liabilities	1	16	—	9	1	7

In 2021, Alliant Energy’s, IPL’s and WPL’s derivative assets increased and derivative liabilities decreased primarily as a result of higher natural gas prices. Based on IPL’s and WPL’s natural gas cost recovery mechanisms, this resulted in corresponding decreases in derivative regulatory assets and increases in derivative regulatory liabilities on the balance sheets.

Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At December 31, 2021 and 2020, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered.

Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at December 31, 2021 and 2020. Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement.

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Fair Value Measurements

12 Months Ended

Dec. 31, 2021

Fair Value Measurements

FAIR VALUE MEASUREMENTSValuation Hierarchy - Fair value measurement accounting establishes three levels of fair value hierarchy that prioritize the inputs to valuation techniques used to measure fair value. Level 1 pricing inputs are quoted prices available in active markets for identical assets or liabilities as of the reporting date. Level 2 pricing inputs are quoted prices for similar assets or liabilities in active markets or quoted prices for identical or similar assets or liabilities in markets that are not active as of the reporting date. Level 3 pricing inputs are unobservable inputs for assets or liabilities for which little or no market data exist and require significant management judgment or estimation.

The fair value hierarchy gives the highest priority to quoted prices in active markets (Level 1) and the lowest priority to unobservable data (Level 3). In some cases, the inputs used to measure fair value might fall in different levels of the fair value hierarchy. The lowest level input that is significant to a fair value measurement in its entirety determines the applicable level in the fair value hierarchy. Assessing the significance of a particular input to the fair value measurement in its entirety requires judgment, considering factors specific to the asset or liability.

Valuation Techniques -

Derivative assets and derivative liabilities - Swap, option and physical forward commodity contracts were non-exchange-based derivative instruments and were valued using indicative price quotations from a pricing vendor that provides daily exchange forward price settlements, from broker or dealer quotations, from market publications or from on-line exchanges. The indicative price quotations reflected the average of the bid-ask mid-point prices and were obtained from sources believed to provide the most liquid market for the commodity. A portion of these indicative price quotations were corroborated using quoted prices for similar assets or liabilities in active markets and categorized derivative instruments based on such indicative price quotations as Level 2. Commodity contracts that were valued using indicative price quotations based on significant assumptions such as seasonal or monthly shaping and indicative price quotations that could not be readily corroborated were categorized as Level 3. Swap, option and physical forward commodity contracts were predominately at liquid trading points. FTRs were valued using auction prices and were categorized as Level 3. Refer to Note 15 for additional details of derivative assets and derivative liabilities.

Deferred proceeds (sales of receivables) - The fair value of IPL’s deferred proceeds related to its sales of accounts receivable program was calculated each reporting date using the cost approach valuation technique. The fair value represents the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold due to the short-term nature of the collection period. These inputs were considered unobservable and deferred proceeds were categorized as Level 3. Deferred proceeds represent IPL’s maximum exposure to loss related to the receivables sold. Refer to Note 5(b) for additional information regarding deferred proceeds.

Long-term debt (including current maturities) - The fair value of long-term debt instruments was based on a discounted cash flow methodology using observable data from comparably traded securities with similar credit profiles, and was substantially classified as Level 2. Refer to Note 9(b) for additional information regarding long-term debt.

Fair Value of Financial Instruments - The carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. Carrying amounts and the related estimated fair values of other financial instruments at December 31 were as follows (in millions):

Alliant Energy	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Money market fund investments	$32	$32	$—	$—	$32	$44	$44	$—	$—	$44
Derivatives	176	—	146	30	176	34	—	5	29	34
Deferred proceeds	214	—	—	214	214	188	—	—	188	188
Liabilities and equity:
Derivatives	9	—	8	1	9	25	—	25	—	25
Long-term debt (incl. current maturities)	7,368	—	8,329	1	8,330	6,777	—	8,107	2	8,109

IPL	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Money market fund investments	$32	$32	$—	$—	$32	$44	$44	$—	$—	$44
Derivatives	84	—	65	19	84	29	—	3	26	29
Deferred proceeds	214	—	—	214	214	188	—	—	188	188
Liabilities and equity:
Derivatives	4	—	3	1	4	12	—	12	—	12
Long-term debt	3,643	—	4,124	—	4,124	3,345	—	4,021	—	4,021

WPL	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Derivatives	$92	$—	$81	$11	$92	$5	$—	$2	$3	$5
Liabilities and equity:
Derivatives	5	—	5	—	5	13	—	13	—	13
Long-term debt (incl. current maturities)	2,429	—	2,862	—	2,862	2,130	—	2,690	—	2,690

Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions):

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
	2021	2020	2021	2020
Beginning balance, January 1	$29	$21	$188	$188
Total net gains included in changes in net assets (realized/unrealized)	6	11	—	—
Purchases	21	14	—	—
Sales	(1)	(1)	—	—
Settlements (a)	(26)	(16)	26	—
Ending balance, December 31	$29	$29	$214	$188
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at December 31	$6	$11	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
	2021	2020	2021	2020
Beginning balance, January 1	$26	$18	$188	$188
Total net gains (losses) included in changes in net assets (realized/unrealized)	(3)	10	—	—
Purchases	16	11	—	—
Sales	(1)	(1)	—	—
Settlements (a)	(20)	(12)	26	—
Ending balance, December 31	$18	$26	$214	$188
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at December 31	($3)	$10	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
	2021	2020
Beginning balance, January 1	$3	$3
Total net gains included in changes in net assets (realized/unrealized)	9	1
Purchases	5	3
Settlements	(6)	(4)
Ending balance, December 31	$11	$3
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at December 31	$9	$1

(a)Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold.

Commodity Contracts - The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets at December 31 as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
2021	$9	$20	$8	$10	$1	$10
2020	18	11	17	9	1	2

IPL [Member]

Fair Value Measurements

FAIR VALUE MEASUREMENTSValuation Hierarchy - Fair value measurement accounting establishes three levels of fair value hierarchy that prioritize the inputs to valuation techniques used to measure fair value. Level 1 pricing inputs are quoted prices available in active markets for identical assets or liabilities as of the reporting date. Level 2 pricing inputs are quoted prices for similar assets or liabilities in active markets or quoted prices for identical or similar assets or liabilities in markets that are not active as of the reporting date. Level 3 pricing inputs are unobservable inputs for assets or liabilities for which little or no market data exist and require significant management judgment or estimation.

The fair value hierarchy gives the highest priority to quoted prices in active markets (Level 1) and the lowest priority to unobservable data (Level 3). In some cases, the inputs used to measure fair value might fall in different levels of the fair value hierarchy. The lowest level input that is significant to a fair value measurement in its entirety determines the applicable level in the fair value hierarchy. Assessing the significance of a particular input to the fair value measurement in its entirety requires judgment, considering factors specific to the asset or liability.

Valuation Techniques -

Derivative assets and derivative liabilities - Swap, option and physical forward commodity contracts were non-exchange-based derivative instruments and were valued using indicative price quotations from a pricing vendor that provides daily exchange forward price settlements, from broker or dealer quotations, from market publications or from on-line exchanges. The indicative price quotations reflected the average of the bid-ask mid-point prices and were obtained from sources believed to provide the most liquid market for the commodity. A portion of these indicative price quotations were corroborated using quoted prices for similar assets or liabilities in active markets and categorized derivative instruments based on such indicative price quotations as Level 2. Commodity contracts that were valued using indicative price quotations based on significant assumptions such as seasonal or monthly shaping and indicative price quotations that could not be readily corroborated were categorized as Level 3. Swap, option and physical forward commodity contracts were predominately at liquid trading points. FTRs were valued using auction prices and were categorized as Level 3. Refer to Note 15 for additional details of derivative assets and derivative liabilities.

Deferred proceeds (sales of receivables) - The fair value of IPL’s deferred proceeds related to its sales of accounts receivable program was calculated each reporting date using the cost approach valuation technique. The fair value represents the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold due to the short-term nature of the collection period. These inputs were considered unobservable and deferred proceeds were categorized as Level 3. Deferred proceeds represent IPL’s maximum exposure to loss related to the receivables sold. Refer to Note 5(b) for additional information regarding deferred proceeds.

Long-term debt (including current maturities) - The fair value of long-term debt instruments was based on a discounted cash flow methodology using observable data from comparably traded securities with similar credit profiles, and was substantially classified as Level 2. Refer to Note 9(b) for additional information regarding long-term debt.

Fair Value of Financial Instruments - The carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. Carrying amounts and the related estimated fair values of other financial instruments at December 31 were as follows (in millions):

Alliant Energy	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Money market fund investments	$32	$32	$—	$—	$32	$44	$44	$—	$—	$44
Derivatives	176	—	146	30	176	34	—	5	29	34
Deferred proceeds	214	—	—	214	214	188	—	—	188	188
Liabilities and equity:
Derivatives	9	—	8	1	9	25	—	25	—	25
Long-term debt (incl. current maturities)	7,368	—	8,329	1	8,330	6,777	—	8,107	2	8,109

IPL	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Money market fund investments	$32	$32	$—	$—	$32	$44	$44	$—	$—	$44
Derivatives	84	—	65	19	84	29	—	3	26	29
Deferred proceeds	214	—	—	214	214	188	—	—	188	188
Liabilities and equity:
Derivatives	4	—	3	1	4	12	—	12	—	12
Long-term debt	3,643	—	4,124	—	4,124	3,345	—	4,021	—	4,021

WPL	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Derivatives	$92	$—	$81	$11	$92	$5	$—	$2	$3	$5
Liabilities and equity:
Derivatives	5	—	5	—	5	13	—	13	—	13
Long-term debt (incl. current maturities)	2,429	—	2,862	—	2,862	2,130	—	2,690	—	2,690

Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions):

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
	2021	2020	2021	2020
Beginning balance, January 1	$29	$21	$188	$188
Total net gains included in changes in net assets (realized/unrealized)	6	11	—	—
Purchases	21	14	—	—
Sales	(1)	(1)	—	—
Settlements (a)	(26)	(16)	26	—
Ending balance, December 31	$29	$29	$214	$188
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at December 31	$6	$11	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
	2021	2020	2021	2020
Beginning balance, January 1	$26	$18	$188	$188
Total net gains (losses) included in changes in net assets (realized/unrealized)	(3)	10	—	—
Purchases	16	11	—	—
Sales	(1)	(1)	—	—
Settlements (a)	(20)	(12)	26	—
Ending balance, December 31	$18	$26	$214	$188
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at December 31	($3)	$10	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
	2021	2020
Beginning balance, January 1	$3	$3
Total net gains included in changes in net assets (realized/unrealized)	9	1
Purchases	5	3
Settlements	(6)	(4)
Ending balance, December 31	$11	$3
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at December 31	$9	$1

(a)Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold.

Commodity Contracts - The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets at December 31 as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
2021	$9	$20	$8	$10	$1	$10
2020	18	11	17	9	1	2

WPL [Member]

Fair Value Measurements

FAIR VALUE MEASUREMENTSValuation Hierarchy - Fair value measurement accounting establishes three levels of fair value hierarchy that prioritize the inputs to valuation techniques used to measure fair value. Level 1 pricing inputs are quoted prices available in active markets for identical assets or liabilities as of the reporting date. Level 2 pricing inputs are quoted prices for similar assets or liabilities in active markets or quoted prices for identical or similar assets or liabilities in markets that are not active as of the reporting date. Level 3 pricing inputs are unobservable inputs for assets or liabilities for which little or no market data exist and require significant management judgment or estimation.

The fair value hierarchy gives the highest priority to quoted prices in active markets (Level 1) and the lowest priority to unobservable data (Level 3). In some cases, the inputs used to measure fair value might fall in different levels of the fair value hierarchy. The lowest level input that is significant to a fair value measurement in its entirety determines the applicable level in the fair value hierarchy. Assessing the significance of a particular input to the fair value measurement in its entirety requires judgment, considering factors specific to the asset or liability.

Valuation Techniques -

Derivative assets and derivative liabilities - Swap, option and physical forward commodity contracts were non-exchange-based derivative instruments and were valued using indicative price quotations from a pricing vendor that provides daily exchange forward price settlements, from broker or dealer quotations, from market publications or from on-line exchanges. The indicative price quotations reflected the average of the bid-ask mid-point prices and were obtained from sources believed to provide the most liquid market for the commodity. A portion of these indicative price quotations were corroborated using quoted prices for similar assets or liabilities in active markets and categorized derivative instruments based on such indicative price quotations as Level 2. Commodity contracts that were valued using indicative price quotations based on significant assumptions such as seasonal or monthly shaping and indicative price quotations that could not be readily corroborated were categorized as Level 3. Swap, option and physical forward commodity contracts were predominately at liquid trading points. FTRs were valued using auction prices and were categorized as Level 3. Refer to Note 15 for additional details of derivative assets and derivative liabilities.

Deferred proceeds (sales of receivables) - The fair value of IPL’s deferred proceeds related to its sales of accounts receivable program was calculated each reporting date using the cost approach valuation technique. The fair value represents the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold due to the short-term nature of the collection period. These inputs were considered unobservable and deferred proceeds were categorized as Level 3. Deferred proceeds represent IPL’s maximum exposure to loss related to the receivables sold. Refer to Note 5(b) for additional information regarding deferred proceeds.

Long-term debt (including current maturities) - The fair value of long-term debt instruments was based on a discounted cash flow methodology using observable data from comparably traded securities with similar credit profiles, and was substantially classified as Level 2. Refer to Note 9(b) for additional information regarding long-term debt.

Fair Value of Financial Instruments - The carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. Carrying amounts and the related estimated fair values of other financial instruments at December 31 were as follows (in millions):

Alliant Energy	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Money market fund investments	$32	$32	$—	$—	$32	$44	$44	$—	$—	$44
Derivatives	176	—	146	30	176	34	—	5	29	34
Deferred proceeds	214	—	—	214	214	188	—	—	188	188
Liabilities and equity:
Derivatives	9	—	8	1	9	25	—	25	—	25
Long-term debt (incl. current maturities)	7,368	—	8,329	1	8,330	6,777	—	8,107	2	8,109

IPL	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Money market fund investments	$32	$32	$—	$—	$32	$44	$44	$—	$—	$44
Derivatives	84	—	65	19	84	29	—	3	26	29
Deferred proceeds	214	—	—	214	214	188	—	—	188	188
Liabilities and equity:
Derivatives	4	—	3	1	4	12	—	12	—	12
Long-term debt	3,643	—	4,124	—	4,124	3,345	—	4,021	—	4,021

WPL	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Derivatives	$92	$—	$81	$11	$92	$5	$—	$2	$3	$5
Liabilities and equity:
Derivatives	5	—	5	—	5	13	—	13	—	13
Long-term debt (incl. current maturities)	2,429	—	2,862	—	2,862	2,130	—	2,690	—	2,690

Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions):

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
	2021	2020	2021	2020
Beginning balance, January 1	$29	$21	$188	$188
Total net gains included in changes in net assets (realized/unrealized)	6	11	—	—
Purchases	21	14	—	—
Sales	(1)	(1)	—	—
Settlements (a)	(26)	(16)	26	—
Ending balance, December 31	$29	$29	$214	$188
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at December 31	$6	$11	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
	2021	2020	2021	2020
Beginning balance, January 1	$26	$18	$188	$188
Total net gains (losses) included in changes in net assets (realized/unrealized)	(3)	10	—	—
Purchases	16	11	—	—
Sales	(1)	(1)	—	—
Settlements (a)	(20)	(12)	26	—
Ending balance, December 31	$18	$26	$214	$188
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at December 31	($3)	$10	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
	2021	2020
Beginning balance, January 1	$3	$3
Total net gains included in changes in net assets (realized/unrealized)	9	1
Purchases	5	3
Settlements	(6)	(4)
Ending balance, December 31	$11	$3
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at December 31	$9	$1

(a)Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold.

Commodity Contracts - The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets at December 31 as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
2021	$9	$20	$8	$10	$1	$10
2020	18	11	17	9	1	2

XML

Commitments And Contingencies

12 Months Ended

Dec. 31, 2021

Commitments And Contingencies

COMMITMENTS AND CONTINGENCIES(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects, including WPL’s expansion of solar generation. At December 31, 2021, Alliant Energy’s and WPL’s minimum future commitments in 2022 for these projects were $178 million and $177 million, respectively.(b) Other Purchase Commitments - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase commitments associated with other goods and services. At December 31, 2021, the related minimum future commitments were as follows (in millions):

Alliant Energy	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$307	$196	$144	$102	$88	$175	$1,012
Coal	63	46	25	3	—	—	137
Other (a)	82	14	8	5	2	25	136
	$452	$256	$177	$110	$90	$200	$1,285

IPL	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$148	$108	$84	$52	$42	$65	$499
Coal	32	27	17	3	—	—	79
Other (a)	34	4	2	2	2	23	67
	$214	$139	$103	$57	$44	$88	$645

WPL	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$159	$88	$60	$50	$46	$110	$513
Coal	31	19	8	—	—	—	58
Other (a)	33	1	1	1	1	—	37
	$223	$108	$69	$51	$47	$110	$608

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at December 31, 2021.

(c) Legal Proceedings - Alliant Energy, IPL and WPL are involved in legal and administrative proceedings before various courts and agencies with respect to matters arising in the ordinary course of business. Although unable to predict the outcome of these matters, Alliant Energy, IPL and WPL believe that appropriate reserves have been established and final disposition of these actions will not have a material effect on their financial condition or results of operations.(d) Guarantees and Indemnifications -

Whiting Petroleum - Whiting Petroleum is an independent oil and gas company. In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee the partnership obligations of an affiliate of Whiting Petroleum under multiple general partnership agreements in the oil and gas industry. The guarantees do not include a maximum limit. Based on information made available to Alliant Energy by Whiting Petroleum, the Whiting Petroleum affiliate holds an approximate 6% share in the partnerships, and currently known obligations include costs associated with the future abandonment of certain facilities owned by the partnerships. The general partnerships were formed under California law, and Alliant Energy Resources, LLC may need to perform under the guarantees if the affiliate of Whiting Petroleum is unable to meet its partnership obligations.

As of December 31, 2021, the currently known partnership obligations for the abandonment obligations are estimated at $60 million, which represents Alliant Energy’s currently estimated maximum exposure under the guarantees. Alliant Energy estimates its expected loss to be a portion of the $60 million of known partnership abandonment obligations of the Whiting Petroleum affiliate and the other partners. Alliant Energy is not aware of any material liabilities related to these guarantees that it is probable that it will be obligated to pay; however, as of both December 31, 2021 and 2020, a liability of $5 million is recorded in “Other liabilities” on Alliant Energy’s balance sheets for expected credit losses related to the contingent obligations that are in the scope of these guarantees.

Non-utility Wind Farm in Oklahoma - In 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third-party under a long-term PPA. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and PPA. Alliant Energy’s obligations under the operating agreement were $67 million as of December 31, 2021 and will reduce annually until expiring in July 2047. Alliant Energy’s obligations under the PPA are subject to a maximum limit of $17 million and expire in December 2031, subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of December 31, 2021 and 2020.

(e) Environmental Matters - Alliant Energy, IPL and WPL are subject to environmental regulations as a result of their current and past operations. These regulations are designed to protect public health and the environment and have resulted in compliance, remediation, containment and monitoring obligations, which are recorded as current and non-current environmental liabilities. Substantially all of the environmental liabilities recorded on the balance sheets relate to MGP sites.

Manufactured Gas Plant Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At December 31, 2021, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At December 31, 2021, such amounts for WPL were not material.

	Alliant Energy			IPL
Range of estimated future costs	$8	-	$24	$6	-	$18
Current and non-current environmental liabilities	11			8

IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential CAA issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include fuel switching or retiring Prairie Creek Units 1 and 3 by December 31, 2025. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers.

Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however future capital investments and/or modifications to EGUs and electric and gas distribution systems to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Effluent Limitation Guidelines, CCR Rule, and various legislation and EPA regulations to monitor and regulate the emission of GHG, including the CAA.

(f) Credit Risk - IPL provides retail electric and gas services in Iowa and wholesale electric service in Minnesota, Illinois and Iowa. WPL provides retail electric and gas services and wholesale electric service in Wisconsin. The geographic concentration of IPL’s and WPL’s customers did not contribute significantly to overall credit risk exposure. In addition, as a result of a diverse customer base, IPL and WPL did not have any significant credit risk concentration for receivables arising from the sale of electricity or gas services.

Alliant Energy, IPL and WPL are subject to credit risk related to the ability of counterparties to meet their contractual payment obligations or the potential non-performance of counterparties to deliver contracted commodities and other goods or services at the contracted price. Credit policies are maintained to mitigate credit risk. These credit policies include evaluation of the financial condition of certain counterparties, use of credit risk-related contingent provisions in certain agreements that require credit support from counterparties not meeting specific criteria, diversification of counterparties to reduce concentrations of credit risk and the use of standardized agreements that facilitate the netting of cash flows associated with certain counterparties. Based on these credit policies and counterparty diversification, as well as utility cost recovery mechanisms, it is unlikely that counterparty non-performance would have a material effect on financial condition or results of operations. However, there is no assurance that these items will protect against all losses from counterparty non-performance.

Refer to Notes 5(a) and 15 for details of allowances for expected credit losses and credit risk-related contingent features, respectively.

(g) Collective Bargaining Agreements - At December 31, 2021, employees covered by collective bargaining agreements represented 54%, 69% and 83% of total employees of Alliant Energy, IPL and WPL, respectively. In May 2022, WPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 965 expires, representing 26% and 83% of total employees of Alliant Energy and WPL, respectively.

IPL [Member]

Commitments And Contingencies

COMMITMENTS AND CONTINGENCIES(b) Other Purchase Commitments - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase commitments associated with other goods and services. At December 31, 2021, the related minimum future commitments were as follows (in millions):

Alliant Energy	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$307	$196	$144	$102	$88	$175	$1,012
Coal	63	46	25	3	—	—	137
Other (a)	82	14	8	5	2	25	136
	$452	$256	$177	$110	$90	$200	$1,285

IPL	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$148	$108	$84	$52	$42	$65	$499
Coal	32	27	17	3	—	—	79
Other (a)	34	4	2	2	2	23	67
	$214	$139	$103	$57	$44	$88	$645

WPL	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$159	$88	$60	$50	$46	$110	$513
Coal	31	19	8	—	—	—	58
Other (a)	33	1	1	1	1	—	37
	$223	$108	$69	$51	$47	$110	$608

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at December 31, 2021.

(c) Legal Proceedings - Alliant Energy, IPL and WPL are involved in legal and administrative proceedings before various courts and agencies with respect to matters arising in the ordinary course of business. Although unable to predict the outcome of these matters, Alliant Energy, IPL and WPL believe that appropriate reserves have been established and final disposition of these actions will not have a material effect on their financial condition or results of operations.(e) Environmental Matters - Alliant Energy, IPL and WPL are subject to environmental regulations as a result of their current and past operations. These regulations are designed to protect public health and the environment and have resulted in compliance, remediation, containment and monitoring obligations, which are recorded as current and non-current environmental liabilities. Substantially all of the environmental liabilities recorded on the balance sheets relate to MGP sites.

Manufactured Gas Plant Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At December 31, 2021, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At December 31, 2021, such amounts for WPL were not material.

	Alliant Energy			IPL
Range of estimated future costs	$8	-	$24	$6	-	$18
Current and non-current environmental liabilities	11			8

IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential CAA issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include fuel switching or retiring Prairie Creek Units 1 and 3 by December 31, 2025. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers.

Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however future capital investments and/or modifications to EGUs and electric and gas distribution systems to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Effluent Limitation Guidelines, CCR Rule, and various legislation and EPA regulations to monitor and regulate the emission of GHG, including the CAA.

(f) Credit Risk - IPL provides retail electric and gas services in Iowa and wholesale electric service in Minnesota, Illinois and Iowa. WPL provides retail electric and gas services and wholesale electric service in Wisconsin. The geographic concentration of IPL’s and WPL’s customers did not contribute significantly to overall credit risk exposure. In addition, as a result of a diverse customer base, IPL and WPL did not have any significant credit risk concentration for receivables arising from the sale of electricity or gas services.

Alliant Energy, IPL and WPL are subject to credit risk related to the ability of counterparties to meet their contractual payment obligations or the potential non-performance of counterparties to deliver contracted commodities and other goods or services at the contracted price. Credit policies are maintained to mitigate credit risk. These credit policies include evaluation of the financial condition of certain counterparties, use of credit risk-related contingent provisions in certain agreements that require credit support from counterparties not meeting specific criteria, diversification of counterparties to reduce concentrations of credit risk and the use of standardized agreements that facilitate the netting of cash flows associated with certain counterparties. Based on these credit policies and counterparty diversification, as well as utility cost recovery mechanisms, it is unlikely that counterparty non-performance would have a material effect on financial condition or results of operations. However, there is no assurance that these items will protect against all losses from counterparty non-performance.

Refer to Notes 5(a) and 15 for details of allowances for expected credit losses and credit risk-related contingent features, respectively.

(g) Collective Bargaining Agreements - At December 31, 2021, employees covered by collective bargaining agreements represented 54%, 69% and 83% of total employees of Alliant Energy, IPL and WPL, respectively. In May 2022, WPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 965 expires, representing 26% and 83% of total employees of Alliant Energy and WPL, respectively.

WPL [Member]

Commitments And Contingencies

COMMITMENTS AND CONTINGENCIES(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects, including WPL’s expansion of solar generation. At December 31, 2021, Alliant Energy’s and WPL’s minimum future commitments in 2022 for these projects were $178 million and $177 million, respectively.(b) Other Purchase Commitments - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase commitments associated with other goods and services. At December 31, 2021, the related minimum future commitments were as follows (in millions):

Alliant Energy	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$307	$196	$144	$102	$88	$175	$1,012
Coal	63	46	25	3	—	—	137
Other (a)	82	14	8	5	2	25	136
	$452	$256	$177	$110	$90	$200	$1,285

IPL	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$148	$108	$84	$52	$42	$65	$499
Coal	32	27	17	3	—	—	79
Other (a)	34	4	2	2	2	23	67
	$214	$139	$103	$57	$44	$88	$645

WPL	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$159	$88	$60	$50	$46	$110	$513
Coal	31	19	8	—	—	—	58
Other (a)	33	1	1	1	1	—	37
	$223	$108	$69	$51	$47	$110	$608

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at December 31, 2021.

(c) Legal Proceedings - Alliant Energy, IPL and WPL are involved in legal and administrative proceedings before various courts and agencies with respect to matters arising in the ordinary course of business. Although unable to predict the outcome of these matters, Alliant Energy, IPL and WPL believe that appropriate reserves have been established and final disposition of these actions will not have a material effect on their financial condition or results of operations.(e) Environmental Matters - Alliant Energy, IPL and WPL are subject to environmental regulations as a result of their current and past operations. These regulations are designed to protect public health and the environment and have resulted in compliance, remediation, containment and monitoring obligations, which are recorded as current and non-current environmental liabilities. Substantially all of the environmental liabilities recorded on the balance sheets relate to MGP sites.

Manufactured Gas Plant Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At December 31, 2021, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At December 31, 2021, such amounts for WPL were not material.

	Alliant Energy			IPL
Range of estimated future costs	$8	-	$24	$6	-	$18
Current and non-current environmental liabilities	11			8

IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential CAA issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include fuel switching or retiring Prairie Creek Units 1 and 3 by December 31, 2025. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers.

Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however future capital investments and/or modifications to EGUs and electric and gas distribution systems to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Effluent Limitation Guidelines, CCR Rule, and various legislation and EPA regulations to monitor and regulate the emission of GHG, including the CAA.

(f) Credit Risk - IPL provides retail electric and gas services in Iowa and wholesale electric service in Minnesota, Illinois and Iowa. WPL provides retail electric and gas services and wholesale electric service in Wisconsin. The geographic concentration of IPL’s and WPL’s customers did not contribute significantly to overall credit risk exposure. In addition, as a result of a diverse customer base, IPL and WPL did not have any significant credit risk concentration for receivables arising from the sale of electricity or gas services.

Alliant Energy, IPL and WPL are subject to credit risk related to the ability of counterparties to meet their contractual payment obligations or the potential non-performance of counterparties to deliver contracted commodities and other goods or services at the contracted price. Credit policies are maintained to mitigate credit risk. These credit policies include evaluation of the financial condition of certain counterparties, use of credit risk-related contingent provisions in certain agreements that require credit support from counterparties not meeting specific criteria, diversification of counterparties to reduce concentrations of credit risk and the use of standardized agreements that facilitate the netting of cash flows associated with certain counterparties. Based on these credit policies and counterparty diversification, as well as utility cost recovery mechanisms, it is unlikely that counterparty non-performance would have a material effect on financial condition or results of operations. However, there is no assurance that these items will protect against all losses from counterparty non-performance.

Refer to Notes 5(a) and 15 for details of allowances for expected credit losses and credit risk-related contingent features, respectively.

(g) Collective Bargaining Agreements - At December 31, 2021, employees covered by collective bargaining agreements represented 54%, 69% and 83% of total employees of Alliant Energy, IPL and WPL, respectively. In May 2022, WPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 965 expires, representing 26% and 83% of total employees of Alliant Energy and WPL, respectively.

XML

Segments Of Business

12 Months Ended

Dec. 31, 2021

Segment Reporting Information [Line Items]

Segments Of Business

SEGMENTS OF BUSINESS

Alliant Energy - Alliant Energy’s principal businesses as of December 31, 2021 are:

•Utility - includes the operations of IPL and WPL, which primarily serve retail customers in Iowa and Wisconsin. The utility business has three reportable segments: a) utility electric operations; b) utility gas operations; and c) utility other, which includes steam operations and the unallocated portions of the utility business. Various line items in the following tables are not allocated to the electric and gas segments for management reporting purposes, and therefore, are included only in “Total Utility.”

•ATC Holdings, Non-utility, Parent and Other - includes the operations of AEF and its subsidiaries, Corporate Services, the Alliant Energy parent company, and any Alliant Energy parent company consolidating adjustments. AEF is comprised of Alliant Energy’s interest in ATC Holdings, Travero, a non-utility wind farm, corporate venture investments, the Sheboygan Falls Energy Facility and other non-utility holdings.

Alliant Energy’s administrative support services are directly charged to the applicable segment where practicable. In all other cases, administrative support services are allocated to the applicable segment based on services agreements. Intersegment revenues were not material to Alliant Energy’s operations and there was no single customer whose revenues were 10% or more of Alliant Energy’s consolidated revenues. All of Alliant Energy’s operations and assets are located in the U.S. Certain financial information relating to Alliant Energy’s business segments, which represent the services provided to its customers, was as follows (in millions):

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2021	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$3,081	$456	$49	$3,586	$83	$3,669
Depreciation and amortization	591	54	6	651	6	657
Operating income (loss)	716	63	(11)	768	27	795
Interest expense				244	33	277
Equity income from unconsolidated investments, net	(2)	—	—	(2)	(60)	(62)
Income tax expense (benefit)				(87)	13	(74)
Net income attributable to Alliant Energy common shareowners				618	41	659
Total assets	14,924	1,487	1,103	17,514	1,039	18,553
Investments in equity method subsidiaries	17	—	—	17	491	508
Construction and acquisition expenditures	980	90	—	1,070	99	1,169

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2020	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$2,920	$373	$49	$3,342	$74	$3,416
Depreciation and amortization	556	49	5	610	5	615
Operating income (loss)	643	74	(1)	716	24	740
Interest expense				243	32	275
Equity income from unconsolidated investments, net	(2)	—	—	(2)	(59)	(61)
Income tax expense (benefit)				(66)	9	(57)
Net income attributable to Alliant Energy common shareowners				573	41	614
Total assets	14,358	1,413	990	16,761	949	17,710
Investments in equity method subsidiaries	11	—	—	11	465	476
Construction and acquisition expenditures	1,109	182	2	1,293	73	1,366

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2019	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$3,064	$455	$46	$3,565	$83	$3,648
Depreciation and amortization	513	47	3	563	4	567
Operating income	679	70	1	750	28	778
Interest expense				229	44	273
Equity income from unconsolidated investments, net	(1)	—	—	(1)	(52)	(53)
Income tax expense (benefit)				73	(4)	69
Net income attributable to Alliant Energy common shareowners				517	40	557
Total assets	13,659	1,269	856	15,784	917	16,701
Investments in equity method subsidiaries	9	—	—	9	449	458
Construction and acquisition expenditures	1,439	100	—	1,539	101	1,640

IPL - IPL is a utility primarily serving retail customers in Iowa and includes three reportable segments: a) electric operations; b) gas operations; and c) other, which includes steam operations and the unallocated portions of the utility business. Various line items in the following tables are not allocated to the electric and gas segments for management reporting purposes, and therefore, are included only in “Total.” Intersegment revenues were not material to IPL’s operations and there was no single customer whose revenues were 10% or more of IPL’s consolidated revenues. All of IPL’s operations and assets are located in the U.S. Certain financial information relating to IPL’s business segments, which represent the services provided to its customers, was as follows (in millions):

2021	Electric	Gas	Other	Total
Revenues	$1,752	$265	$46	$2,063
Depreciation and amortization	338	31	6	375
Operating income (loss)	420	43	(3)	460
Interest expense				139
Income tax benefit				(36)
Net income available for common stock				350
Total assets	8,602	819	575	9,996
Construction and acquisition expenditures	342	42	—	384

2020	Electric	Gas	Other	Total
Revenues	$1,695	$208	$44	$1,947
Depreciation and amortization	321	30	5	356
Operating income	358	50	2	410
Interest expense				139
Income tax benefit				(47)
Net income available for common stock				324
Total assets	8,518	766	565	9,849
Construction and acquisition expenditures	626	59	2	687

2019	Electric	Gas	Other	Total
Revenues	$1,781	$264	$44	$2,089
Depreciation and amortization	295	29	3	327
Operating income	360	39	4	403
Interest expense				127
Income taxes				24
Net income available for common stock				284
Total assets	8,075	734	468	9,277
Construction and acquisition expenditures	964	56	—	1,020

WPL - WPL is a utility serving customers in Wisconsin and includes three reportable segments: a) electric operations; b) gas operations; and c) other, which includes the unallocated portions of the utility business. Various line items in the following tables are not allocated to the electric and gas segments for management reporting purposes, and therefore, are included only in “Total.” Intersegment revenues were not material to WPL’s operations and there was no single customer whose revenues were 10% or more of WPL’s consolidated revenues. All of WPL’s operations and assets are located in the U.S. Certain financial information relating to WPL’s business segments, which represent the services provided to its customers, was as follows (in millions):

2021	Electric	Gas	Other	Total
Revenues	$1,329	$191	$3	$1,523
Depreciation and amortization	253	23	—	276
Operating income (loss)	296	20	(8)	308
Interest expense				105
Income tax benefit				(51)
Net income				268
Total assets	6,322	668	528	7,518
Construction and acquisition expenditures	638	48	—	686

2020	Electric	Gas	Other	Total
Revenues	$1,225	$165	$5	$1,395
Depreciation and amortization	235	19	—	254
Operating income (loss)	285	24	(3)	306
Interest expense				104
Income tax benefit				(19)
Net income				249
Total assets	5,840	647	425	6,912
Construction and acquisition expenditures	483	123	—	606

2019	Electric	Gas	Other	Total
Revenues	$1,283	$191	$2	$1,476
Depreciation and amortization	218	18	—	236
Operating income (loss)	319	31	(3)	347
Interest expense				102
Income taxes				49
Net income				233
Total assets	5,584	535	388	6,507
Construction and acquisition expenditures	475	44	—	519

IPL [Member]

Segment Reporting Information [Line Items]

Segments Of Business

SEGMENTS OF BUSINESS

Alliant Energy - Alliant Energy’s principal businesses as of December 31, 2021 are:

•Utility - includes the operations of IPL and WPL, which primarily serve retail customers in Iowa and Wisconsin. The utility business has three reportable segments: a) utility electric operations; b) utility gas operations; and c) utility other, which includes steam operations and the unallocated portions of the utility business. Various line items in the following tables are not allocated to the electric and gas segments for management reporting purposes, and therefore, are included only in “Total Utility.”

•ATC Holdings, Non-utility, Parent and Other - includes the operations of AEF and its subsidiaries, Corporate Services, the Alliant Energy parent company, and any Alliant Energy parent company consolidating adjustments. AEF is comprised of Alliant Energy’s interest in ATC Holdings, Travero, a non-utility wind farm, corporate venture investments, the Sheboygan Falls Energy Facility and other non-utility holdings.

Alliant Energy’s administrative support services are directly charged to the applicable segment where practicable. In all other cases, administrative support services are allocated to the applicable segment based on services agreements. Intersegment revenues were not material to Alliant Energy’s operations and there was no single customer whose revenues were 10% or more of Alliant Energy’s consolidated revenues. All of Alliant Energy’s operations and assets are located in the U.S. Certain financial information relating to Alliant Energy’s business segments, which represent the services provided to its customers, was as follows (in millions):

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2021	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$3,081	$456	$49	$3,586	$83	$3,669
Depreciation and amortization	591	54	6	651	6	657
Operating income (loss)	716	63	(11)	768	27	795
Interest expense				244	33	277
Equity income from unconsolidated investments, net	(2)	—	—	(2)	(60)	(62)
Income tax expense (benefit)				(87)	13	(74)
Net income attributable to Alliant Energy common shareowners				618	41	659
Total assets	14,924	1,487	1,103	17,514	1,039	18,553
Investments in equity method subsidiaries	17	—	—	17	491	508
Construction and acquisition expenditures	980	90	—	1,070	99	1,169

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2020	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$2,920	$373	$49	$3,342	$74	$3,416
Depreciation and amortization	556	49	5	610	5	615
Operating income (loss)	643	74	(1)	716	24	740
Interest expense				243	32	275
Equity income from unconsolidated investments, net	(2)	—	—	(2)	(59)	(61)
Income tax expense (benefit)				(66)	9	(57)
Net income attributable to Alliant Energy common shareowners				573	41	614
Total assets	14,358	1,413	990	16,761	949	17,710
Investments in equity method subsidiaries	11	—	—	11	465	476
Construction and acquisition expenditures	1,109	182	2	1,293	73	1,366

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2019	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$3,064	$455	$46	$3,565	$83	$3,648
Depreciation and amortization	513	47	3	563	4	567
Operating income	679	70	1	750	28	778
Interest expense				229	44	273
Equity income from unconsolidated investments, net	(1)	—	—	(1)	(52)	(53)
Income tax expense (benefit)				73	(4)	69
Net income attributable to Alliant Energy common shareowners				517	40	557
Total assets	13,659	1,269	856	15,784	917	16,701
Investments in equity method subsidiaries	9	—	—	9	449	458
Construction and acquisition expenditures	1,439	100	—	1,539	101	1,640

IPL - IPL is a utility primarily serving retail customers in Iowa and includes three reportable segments: a) electric operations; b) gas operations; and c) other, which includes steam operations and the unallocated portions of the utility business. Various line items in the following tables are not allocated to the electric and gas segments for management reporting purposes, and therefore, are included only in “Total.” Intersegment revenues were not material to IPL’s operations and there was no single customer whose revenues were 10% or more of IPL’s consolidated revenues. All of IPL’s operations and assets are located in the U.S. Certain financial information relating to IPL’s business segments, which represent the services provided to its customers, was as follows (in millions):

2021	Electric	Gas	Other	Total
Revenues	$1,752	$265	$46	$2,063
Depreciation and amortization	338	31	6	375
Operating income (loss)	420	43	(3)	460
Interest expense				139
Income tax benefit				(36)
Net income available for common stock				350
Total assets	8,602	819	575	9,996
Construction and acquisition expenditures	342	42	—	384

2020	Electric	Gas	Other	Total
Revenues	$1,695	$208	$44	$1,947
Depreciation and amortization	321	30	5	356
Operating income	358	50	2	410
Interest expense				139
Income tax benefit				(47)
Net income available for common stock				324
Total assets	8,518	766	565	9,849
Construction and acquisition expenditures	626	59	2	687

2019	Electric	Gas	Other	Total
Revenues	$1,781	$264	$44	$2,089
Depreciation and amortization	295	29	3	327
Operating income	360	39	4	403
Interest expense				127
Income taxes				24
Net income available for common stock				284
Total assets	8,075	734	468	9,277
Construction and acquisition expenditures	964	56	—	1,020

WPL - WPL is a utility serving customers in Wisconsin and includes three reportable segments: a) electric operations; b) gas operations; and c) other, which includes the unallocated portions of the utility business. Various line items in the following tables are not allocated to the electric and gas segments for management reporting purposes, and therefore, are included only in “Total.” Intersegment revenues were not material to WPL’s operations and there was no single customer whose revenues were 10% or more of WPL’s consolidated revenues. All of WPL’s operations and assets are located in the U.S. Certain financial information relating to WPL’s business segments, which represent the services provided to its customers, was as follows (in millions):

2021	Electric	Gas	Other	Total
Revenues	$1,329	$191	$3	$1,523
Depreciation and amortization	253	23	—	276
Operating income (loss)	296	20	(8)	308
Interest expense				105
Income tax benefit				(51)
Net income				268
Total assets	6,322	668	528	7,518
Construction and acquisition expenditures	638	48	—	686

2020	Electric	Gas	Other	Total
Revenues	$1,225	$165	$5	$1,395
Depreciation and amortization	235	19	—	254
Operating income (loss)	285	24	(3)	306
Interest expense				104
Income tax benefit				(19)
Net income				249
Total assets	5,840	647	425	6,912
Construction and acquisition expenditures	483	123	—	606

2019	Electric	Gas	Other	Total
Revenues	$1,283	$191	$2	$1,476
Depreciation and amortization	218	18	—	236
Operating income (loss)	319	31	(3)	347
Interest expense				102
Income taxes				49
Net income				233
Total assets	5,584	535	388	6,507
Construction and acquisition expenditures	475	44	—	519

WPL [Member]

Segment Reporting Information [Line Items]

Segments Of Business

SEGMENTS OF BUSINESS

Alliant Energy - Alliant Energy’s principal businesses as of December 31, 2021 are:

•Utility - includes the operations of IPL and WPL, which primarily serve retail customers in Iowa and Wisconsin. The utility business has three reportable segments: a) utility electric operations; b) utility gas operations; and c) utility other, which includes steam operations and the unallocated portions of the utility business. Various line items in the following tables are not allocated to the electric and gas segments for management reporting purposes, and therefore, are included only in “Total Utility.”

•ATC Holdings, Non-utility, Parent and Other - includes the operations of AEF and its subsidiaries, Corporate Services, the Alliant Energy parent company, and any Alliant Energy parent company consolidating adjustments. AEF is comprised of Alliant Energy’s interest in ATC Holdings, Travero, a non-utility wind farm, corporate venture investments, the Sheboygan Falls Energy Facility and other non-utility holdings.

Alliant Energy’s administrative support services are directly charged to the applicable segment where practicable. In all other cases, administrative support services are allocated to the applicable segment based on services agreements. Intersegment revenues were not material to Alliant Energy’s operations and there was no single customer whose revenues were 10% or more of Alliant Energy’s consolidated revenues. All of Alliant Energy’s operations and assets are located in the U.S. Certain financial information relating to Alliant Energy’s business segments, which represent the services provided to its customers, was as follows (in millions):

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2021	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$3,081	$456	$49	$3,586	$83	$3,669
Depreciation and amortization	591	54	6	651	6	657
Operating income (loss)	716	63	(11)	768	27	795
Interest expense				244	33	277
Equity income from unconsolidated investments, net	(2)	—	—	(2)	(60)	(62)
Income tax expense (benefit)				(87)	13	(74)
Net income attributable to Alliant Energy common shareowners				618	41	659
Total assets	14,924	1,487	1,103	17,514	1,039	18,553
Investments in equity method subsidiaries	17	—	—	17	491	508
Construction and acquisition expenditures	980	90	—	1,070	99	1,169

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2020	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$2,920	$373	$49	$3,342	$74	$3,416
Depreciation and amortization	556	49	5	610	5	615
Operating income (loss)	643	74	(1)	716	24	740
Interest expense				243	32	275
Equity income from unconsolidated investments, net	(2)	—	—	(2)	(59)	(61)
Income tax expense (benefit)				(66)	9	(57)
Net income attributable to Alliant Energy common shareowners				573	41	614
Total assets	14,358	1,413	990	16,761	949	17,710
Investments in equity method subsidiaries	11	—	—	11	465	476
Construction and acquisition expenditures	1,109	182	2	1,293	73	1,366

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2019	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$3,064	$455	$46	$3,565	$83	$3,648
Depreciation and amortization	513	47	3	563	4	567
Operating income	679	70	1	750	28	778
Interest expense				229	44	273
Equity income from unconsolidated investments, net	(1)	—	—	(1)	(52)	(53)
Income tax expense (benefit)				73	(4)	69
Net income attributable to Alliant Energy common shareowners				517	40	557
Total assets	13,659	1,269	856	15,784	917	16,701
Investments in equity method subsidiaries	9	—	—	9	449	458
Construction and acquisition expenditures	1,439	100	—	1,539	101	1,640

IPL - IPL is a utility primarily serving retail customers in Iowa and includes three reportable segments: a) electric operations; b) gas operations; and c) other, which includes steam operations and the unallocated portions of the utility business. Various line items in the following tables are not allocated to the electric and gas segments for management reporting purposes, and therefore, are included only in “Total.” Intersegment revenues were not material to IPL’s operations and there was no single customer whose revenues were 10% or more of IPL’s consolidated revenues. All of IPL’s operations and assets are located in the U.S. Certain financial information relating to IPL’s business segments, which represent the services provided to its customers, was as follows (in millions):

2021	Electric	Gas	Other	Total
Revenues	$1,752	$265	$46	$2,063
Depreciation and amortization	338	31	6	375
Operating income (loss)	420	43	(3)	460
Interest expense				139
Income tax benefit				(36)
Net income available for common stock				350
Total assets	8,602	819	575	9,996
Construction and acquisition expenditures	342	42	—	384

2020	Electric	Gas	Other	Total
Revenues	$1,695	$208	$44	$1,947
Depreciation and amortization	321	30	5	356
Operating income	358	50	2	410
Interest expense				139
Income tax benefit				(47)
Net income available for common stock				324
Total assets	8,518	766	565	9,849
Construction and acquisition expenditures	626	59	2	687

2019	Electric	Gas	Other	Total
Revenues	$1,781	$264	$44	$2,089
Depreciation and amortization	295	29	3	327
Operating income	360	39	4	403
Interest expense				127
Income taxes				24
Net income available for common stock				284
Total assets	8,075	734	468	9,277
Construction and acquisition expenditures	964	56	—	1,020

WPL - WPL is a utility serving customers in Wisconsin and includes three reportable segments: a) electric operations; b) gas operations; and c) other, which includes the unallocated portions of the utility business. Various line items in the following tables are not allocated to the electric and gas segments for management reporting purposes, and therefore, are included only in “Total.” Intersegment revenues were not material to WPL’s operations and there was no single customer whose revenues were 10% or more of WPL’s consolidated revenues. All of WPL’s operations and assets are located in the U.S. Certain financial information relating to WPL’s business segments, which represent the services provided to its customers, was as follows (in millions):

2021	Electric	Gas	Other	Total
Revenues	$1,329	$191	$3	$1,523
Depreciation and amortization	253	23	—	276
Operating income (loss)	296	20	(8)	308
Interest expense				105
Income tax benefit				(51)
Net income				268
Total assets	6,322	668	528	7,518
Construction and acquisition expenditures	638	48	—	686

2020	Electric	Gas	Other	Total
Revenues	$1,225	$165	$5	$1,395
Depreciation and amortization	235	19	—	254
Operating income (loss)	285	24	(3)	306
Interest expense				104
Income tax benefit				(19)
Net income				249
Total assets	5,840	647	425	6,912
Construction and acquisition expenditures	483	123	—	606

2019	Electric	Gas	Other	Total
Revenues	$1,283	$191	$2	$1,476
Depreciation and amortization	218	18	—	236
Operating income (loss)	319	31	(3)	347
Interest expense				102
Income taxes				49
Net income				233
Total assets	5,584	535	388	6,507
Construction and acquisition expenditures	475	44	—	519

XML

Related Parties

12 Months Ended

Dec. 31, 2021

Related Party Transaction [Line Items]

Related Parties

RELATED PARTIES

Service Agreements - Pursuant to service agreements, IPL and WPL receive various administrative and general services from an affiliate, Corporate Services. These services are billed to IPL and WPL at cost based on expenses incurred by Corporate Services for the benefit of IPL and WPL, respectively. These costs consisted primarily of employee compensation and benefits, fees associated with various professional services, depreciation and amortization of property, plant and equipment, and a return on net assets. Corporate Services also acts as agent on behalf of IPL and WPL pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases among IPL and WPL based on statements received from MISO. The amounts billed for services provided, sales credited and purchases were as follows (in millions):

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Corporate Services billings	$180	$176	$185	$154	$142	$142
Sales credited	22	35	68	23	3	7
Purchases billed	441	329	331	116	108	120

As of December 31, net intercompany payables to Corporate Services were as follows (in millions):

	2021	2020
IPL	$110	$110
WPL	83	73

ATC - Pursuant to various agreements, WPL receives a range of transmission services from ATC. WPL provides operation, maintenance, and construction services to ATC. WPL and ATC also bill each other for use of shared facilities owned by each party. The related amounts billed between the parties were as follows (in millions):

	2021	2020	2019
ATC billings to WPL	$122	$108	$109
WPL billings to ATC	18	10	13

As of December 31, 2021 and 2020, WPL owed ATC net amounts of $10 million and $9 million, respectively.

In 2020, WPL received $46 million from ATC related to construction deposits WPL previously provided ATC for transmission network upgrades for West Riverside, which is substantially recorded in “Other” in Alliant Energy’s and WPL’s cash flows from investing activities.

WPL’s Sheboygan Falls Energy Facility Lease - Refer to Note 10 for discussion of WPL’s Sheboygan Falls Energy Facility lease.

IPL [Member]

Related Party Transaction [Line Items]

Related Parties

RELATED PARTIES

Service Agreements - Pursuant to service agreements, IPL and WPL receive various administrative and general services from an affiliate, Corporate Services. These services are billed to IPL and WPL at cost based on expenses incurred by Corporate Services for the benefit of IPL and WPL, respectively. These costs consisted primarily of employee compensation and benefits, fees associated with various professional services, depreciation and amortization of property, plant and equipment, and a return on net assets. Corporate Services also acts as agent on behalf of IPL and WPL pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases among IPL and WPL based on statements received from MISO. The amounts billed for services provided, sales credited and purchases were as follows (in millions):

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Corporate Services billings	$180	$176	$185	$154	$142	$142
Sales credited	22	35	68	23	3	7
Purchases billed	441	329	331	116	108	120

As of December 31, net intercompany payables to Corporate Services were as follows (in millions):

	2021	2020
IPL	$110	$110
WPL	83	73

WPL [Member]

Related Party Transaction [Line Items]

Related Parties

RELATED PARTIES

Service Agreements - Pursuant to service agreements, IPL and WPL receive various administrative and general services from an affiliate, Corporate Services. These services are billed to IPL and WPL at cost based on expenses incurred by Corporate Services for the benefit of IPL and WPL, respectively. These costs consisted primarily of employee compensation and benefits, fees associated with various professional services, depreciation and amortization of property, plant and equipment, and a return on net assets. Corporate Services also acts as agent on behalf of IPL and WPL pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases among IPL and WPL based on statements received from MISO. The amounts billed for services provided, sales credited and purchases were as follows (in millions):

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Corporate Services billings	$180	$176	$185	$154	$142	$142
Sales credited	22	35	68	23	3	7
Purchases billed	441	329	331	116	108	120

As of December 31, net intercompany payables to Corporate Services were as follows (in millions):

	2021	2020
IPL	$110	$110
WPL	83	73

ATC - Pursuant to various agreements, WPL receives a range of transmission services from ATC. WPL provides operation, maintenance, and construction services to ATC. WPL and ATC also bill each other for use of shared facilities owned by each party. The related amounts billed between the parties were as follows (in millions):

	2021	2020	2019
ATC billings to WPL	$122	$108	$109
WPL billings to ATC	18	10	13

As of December 31, 2021 and 2020, WPL owed ATC net amounts of $10 million and $9 million, respectively.

In 2020, WPL received $46 million from ATC related to construction deposits WPL previously provided ATC for transmission network upgrades for West Riverside, which is substantially recorded in “Other” in Alliant Energy’s and WPL’s cash flows from investing activities.

WPL’s Sheboygan Falls Energy Facility Lease - Refer to Note 10 for discussion of WPL’s Sheboygan Falls Energy Facility lease.

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Condensed Parent Company Financial Statements

12 Months Ended

Dec. 31, 2021

Condensed Financial Information Disclosure [Abstract]

Condensed Parent Company Financial Statements

SCHEDULE I - CONDENSED PARENT COMPANY FINANCIAL STATEMENTS

ALLIANT ENERGY CORPORATION (Parent Company Only)	Year Ended December 31,
CONDENSED STATEMENTS OF INCOME	2021	2020	2019
	(in millions)
Operating expenses	$5	$7	$2
Operating loss	(5)	(7)	(2)
Other (income) and deductions:
Equity earnings from consolidated subsidiaries	(664)	(625)	(562)
Interest expense	1	2	9
Other	1	4	7
Total other (income) and deductions	(662)	(619)	(546)
Income before income taxes	657	612	544
Income tax benefit	(5)	(4)	(15)
Net income	$662	$616	$559

Refer to accompanying Notes to Condensed Financial Statements.

ALLIANT ENERGY CORPORATION (Parent Company Only)	December 31,
CONDENSED BALANCE SHEETS	2021	2020
	(in millions)
ASSETS
Current assets:
Notes receivable from affiliated companies	$16	$32
Other	5	5
Total current assets	21	37
Investments:
Investments in consolidated subsidiaries	7,061	6,664
Other	2	2
Total investments	7,063	6,666
Other assets	96	88
Total assets	$7,180	$6,791

LIABILITIES AND EQUITY
Current liabilities:
Commercial paper	$279	$132
Notes payable to affiliated companies	900	937
Other	4	29
Total current liabilities	1,183	1,098
Other liabilities	2	2
Common equity:
Common stock and additional paid-in capital	2,752	2,706
Retained earnings	3,255	2,996
Shares in deferred compensation trust	(12)	(11)
Total common equity	5,995	5,691
Total liabilities and equity	$7,180	$6,791

Refer to accompanying Notes to Condensed Financial Statements.

ALLIANT ENERGY CORPORATION (Parent Company Only)	Year Ended December 31,
CONDENSED STATEMENTS OF CASH FLOWS	2021	2020	2019
	(in millions)
Net cash flows from operating activities	$494	$396	$305
Cash flows used for investing activities:
Capital contributions to consolidated subsidiaries	(295)	(429)	(250)
Net change in notes receivable from and payable to affiliates	(21)	201	8
Dividends from consolidated subsidiaries in excess of equity earnings	50	—	—
Net cash flows used for investing activities	(266)	(228)	(242)
Cash flows used for financing activities:
Common stock dividends	(403)	(377)	(338)
Proceeds from issuance of common stock, net	28	247	390
Net change in commercial paper	147	(37)	(116)
Other	—	(1)	1
Net cash flows used for financing activities	(228)	(168)	(63)
Net increase (decrease) in cash, cash equivalents and restricted cash	—	—	—
Cash, cash equivalents and restricted cash at beginning of period	—	—	—
Cash, cash equivalents and restricted cash at end of period	$—	$—	$—
Supplemental cash flows information:
Cash (paid) refunded during the period for:
Interest	($1)	($2)	($9)
Income taxes, net	4	10	14

Refer to accompanying Notes to Condensed Financial Statements.

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Valuation and Qualifying Accounts And Reserves

12 Months Ended

Dec. 31, 2021

SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]

Valuation and Qualifying Accounts And Reserves

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES

		Additions
	Balance,	Charged to	Charged to Other		Balance,
Description	January 1	Expense	Accounts (a)	Deductions (b)	December 31
	(in millions)

Valuation and Qualifying Accounts Which are Deducted in the Balance Sheet from the Assets to Which They Apply:

Accumulated Provision for Uncollectible Accounts:
	Alliant Energy (c)
		Year ended December 31, 2021	$18	$12	$—	$19	$11
		Year ended December 31, 2020	7	25	9	23	18
		Year ended December 31, 2019	10	17	2	22	7
	IPL (c)
		Year ended December 31, 2021	$1	$6	$—	$6	$1
		Year ended December 31, 2020	1	18	—	18	1
		Year ended December 31, 2019	3	16	—	18	1
	WPL
		Year ended December 31, 2021	$17	$6	$—	$13	$10
		Year ended December 31, 2020	6	7	9	5	17
		Year ended December 31, 2019	7	1	2	4	6

Note: The above provisions relate to various customer, notes and other receivable balances included in various line items on the respective balance sheets.

(a)Accumulated provision for uncollectible accounts: In accordance with its regulatory treatment, certain amounts provided by WPL are recorded in regulatory assets.

(b)Deductions are of the nature for which the reserves were created. In the case of the accumulated provision for uncollectible accounts, deductions from this reserve are reduced by recoveries of amounts previously written off.

(c)Refer to Note 5(b) for discussion of IPL’s sales of accounts receivable program.

IPL [Member]

SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]

Valuation and Qualifying Accounts And Reserves

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES

		Additions
	Balance,	Charged to	Charged to Other		Balance,
Description	January 1	Expense	Accounts (a)	Deductions (b)	December 31
	(in millions)

Valuation and Qualifying Accounts Which are Deducted in the Balance Sheet from the Assets to Which They Apply:

Accumulated Provision for Uncollectible Accounts:
	Alliant Energy (c)
		Year ended December 31, 2021	$18	$12	$—	$19	$11
		Year ended December 31, 2020	7	25	9	23	18
		Year ended December 31, 2019	10	17	2	22	7
	IPL (c)
		Year ended December 31, 2021	$1	$6	$—	$6	$1
		Year ended December 31, 2020	1	18	—	18	1
		Year ended December 31, 2019	3	16	—	18	1
	WPL
		Year ended December 31, 2021	$17	$6	$—	$13	$10
		Year ended December 31, 2020	6	7	9	5	17
		Year ended December 31, 2019	7	1	2	4	6

Note: The above provisions relate to various customer, notes and other receivable balances included in various line items on the respective balance sheets.

(a)Accumulated provision for uncollectible accounts: In accordance with its regulatory treatment, certain amounts provided by WPL are recorded in regulatory assets.

(b)Deductions are of the nature for which the reserves were created. In the case of the accumulated provision for uncollectible accounts, deductions from this reserve are reduced by recoveries of amounts previously written off.

(c)Refer to Note 5(b) for discussion of IPL’s sales of accounts receivable program.

WPL [Member]

SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]

Valuation and Qualifying Accounts And Reserves

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES

		Additions
	Balance,	Charged to	Charged to Other		Balance,
Description	January 1	Expense	Accounts (a)	Deductions (b)	December 31
	(in millions)

Valuation and Qualifying Accounts Which are Deducted in the Balance Sheet from the Assets to Which They Apply:

Accumulated Provision for Uncollectible Accounts:
	Alliant Energy (c)
		Year ended December 31, 2021	$18	$12	$—	$19	$11
		Year ended December 31, 2020	7	25	9	23	18
		Year ended December 31, 2019	10	17	2	22	7
	IPL (c)
		Year ended December 31, 2021	$1	$6	$—	$6	$1
		Year ended December 31, 2020	1	18	—	18	1
		Year ended December 31, 2019	3	16	—	18	1
	WPL
		Year ended December 31, 2021	$17	$6	$—	$13	$10
		Year ended December 31, 2020	6	7	9	5	17
		Year ended December 31, 2019	7	1	2	4	6

Note: The above provisions relate to various customer, notes and other receivable balances included in various line items on the respective balance sheets.

(a)Accumulated provision for uncollectible accounts: In accordance with its regulatory treatment, certain amounts provided by WPL are recorded in regulatory assets.

(b)Deductions are of the nature for which the reserves were created. In the case of the accumulated provision for uncollectible accounts, deductions from this reserve are reduced by recoveries of amounts previously written off.

(c)Refer to Note 5(b) for discussion of IPL’s sales of accounts receivable program.

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Summary Of Significant Accounting Policies (Policy)

12 Months Ended

Dec. 31, 2021

Property, Plant and Equipment [Line Items]

General, Basis of Presentation

The financial statements reflect investments in controlled subsidiaries on a consolidated basis and Alliant Energy’s, IPL’s and WPL’s proportionate shares of jointly-owned utility EGUs. Unconsolidated investments that Alliant Energy and WPL do not control are accounted for under the equity method of accounting. Under the equity method of accounting, Alliant Energy and WPL initially record the investment at cost, and adjust the carrying amount of the investment to recognize their respective share of the earnings or losses of the investee. Dividends received from an investee reduce the carrying amount of the equity investment. Investments that do not meet the criteria for consolidation or the equity method of accounting are accounted for under the cost method.All intercompany balances and transactions, other than certain transactions affecting the rate-making process at IPL and WPL, have been eliminated from the financial statements. Such transactions not eliminated include costs that are recoverable from customers through rate-making processes.

General, Basis of Accounting

The financial statements are prepared in conformity with GAAP, which give recognition to the rate-making practices of FERC and state commissions having regulatory jurisdiction.

General, Reclassification

Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.

General, Use of Estimates

The preparation of the financial statements requires management to make estimates and assumptions that affect: (a) the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements; and (b) the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

Regulatory Assets and Regulatory Liabilities

Alliant Energy, IPL and WPL are subject to regulation by FERC and various state regulatory commissions. As a result, Alliant Energy, IPL and WPL are subject to GAAP provisions for regulated operations, which provide that rate-regulated public utilities record certain costs and credits allowed in the rate-making process in different periods than for non-utility entities. Regulatory assets generally represent incurred costs that have been deferred as such costs are probable of recovery in future customer rates. Regulatory liabilities generally represent obligations to make refunds to customers or amounts collected in rates for which the related costs have not yet been incurred. Amounts recorded as regulatory assets or regulatory liabilities are generally recognized in the income statements at the time they are reflected in rates.

Income Taxes

The liability method of accounting is followed for deferred taxes, which requires the establishment of deferred tax assets and liabilities, as appropriate, for temporary differences between the tax basis of assets and liabilities and the amounts reported in the financial statements. Deferred taxes are recorded using currently enacted tax rates and estimates of state apportionment. Changes in deferred tax assets and liabilities associated with certain property-related differences at IPL are accounted for differently than other subsidiaries of Alliant Energy due to rate-making practices in Iowa. Rate-making practices in Iowa do not allow the impact of certain deferred tax expenses (benefits) to be included in the determination of retail rates. Based on these rate-making practices, deferred tax expense (benefit) related to these property-related differences at IPL is not recorded in the income statement but instead recorded to regulatory assets or regulatory liabilities until these temporary differences reverse. In Wisconsin, the PSCW allows rate recovery of deferred tax expense on all temporary differences.

Investment tax credits are deferred and amortized to income over the average lives of the related property. Federal Tax Reform repealed corporate federal alternative minimum tax and allowed unutilized alternative minimum tax credits to be refunded over four tax years beginning with the U.S. federal tax return for calendar year 2018. Pursuant to the Coronavirus Aid, Relief, and Economic Security Act, Alliant Energy received the remaining alternative minimum tax credits refunds in 2020. Other tax credits reduce income tax expense in the year claimed.

Alliant Energy files a consolidated federal income tax return and a combined return in Wisconsin, which include Alliant Energy and its subsidiaries. Alliant Energy subsidiaries with a presence in Iowa file as part of a consolidated return in Iowa.

Alliant Energy allocates consolidated income tax expense to its subsidiaries that are members of the group that file a consolidated or combined income tax return. IPL and WPL use the modified separate return approach for calculating their income tax provisions and related deferred tax assets and liabilities. IPL and WPL are assumed to file separate tax returns with the federal and state taxing authorities, except that net operating losses (and other current or deferred tax attributes) are characterized as realized (or realizable) by IPL and WPL when those tax attributes are realized (or realizable) by the consolidated tax return group of Alliant Energy (even if IPL and WPL would not otherwise have realized the attributes on a stand-alone basis). The difference in the income taxes recorded for IPL and WPL under the modified separate return method compared to the income taxes recorded on a separate return basis was not material in 2021, 2020 and 2019.

Cash, Cash Equivalents and Restricted Cash

Cash and cash equivalents include short-term liquid investments that have original maturities of less than 90 days. At December 31, 2021, Alliant Energy’s and IPL’s cash and cash equivalents included $32 million of money market fund investments, with an interest rate of 0.04%. At December 31, 2021 and 2020, Alliant Energy’s restricted cash related to requirements in Sheboygan Power, LLC’s debt agreement.

Property, Plant and Equipment

Utility Plant -

General - Utility plant is recorded at the original cost of acquisition or construction, which includes material, labor, contractor services, AFUDC and allocable overheads, such as supervision, engineering, benefits, certain taxes and transportation. Repairs, replacements and renewals of items of property determined to be less than a unit of property or that do not increase the property’s life or functionality are charged to maintenance expense. Property, plant and equipment that is probable of being retired early is classified as plant anticipated to be retired early. Generally, ordinary retirements of utility plant and salvage value are netted and charged to accumulated depreciation upon removal from utility plant accounts and no gain or loss is recognized consistent with rate-making principles. However, if regulators have approved recovery of the remaining net book value of property, plant and equipment that is retired early, or such approval by regulators is probable, the remaining net book value is reclassified from property, plant and equipment to regulatory assets upon retirement.

Non-utility and Other Property -

General - Non-utility property is recorded at the original cost of acquisition or construction, which includes material, labor and contractor services. Repairs, replacements and renewals of items of property determined to be less than a unit of property or that do not increase the property’s life or functionality are charged to maintenance expense. Upon retirement or sale of non-utility property, the original cost and related accumulated depreciation are removed from the accounts and any gain or loss is included in the income statements.

Costs related to software developed or obtained for internal use are capitalized and amortized on a straight-line basis over the estimated useful life of the related software. If software is retired prior to being fully amortized, the remaining book value is recorded as a loss in the income statements.

Depreciation

IPL and WPL use a combination of remaining life and straight-line depreciation methods as approved by their respective regulatory commissions. The composite or group method of depreciation is used, in which a single depreciation rate is applied to the gross investment in a particular class of property. This method pools similar assets and then depreciates each group as a whole. Periodic depreciation studies are performed to determine the appropriate group lives, net salvage, estimated cost of removal and group depreciation rates. These depreciation studies are subject to review and approval by IPL’s and WPL’s respective regulatory commissions. Depreciation expense is included within the recoverable cost of service component of rates collected from customers. The average rates of depreciation for electric, gas and other properties, consistent with current rate-making practices, were as follows:

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Electric - generation	3.4%	3.5%	3.8%	3.5%	3.5%	3.6%
Electric - distribution	2.9%	2.8%	2.9%	2.6%	2.6%	2.6%
Electric - other	5.7%	5.2%	5.3%	7.4%	6.1%	5.8%
Gas	3.3%	3.3%	3.3%	2.4%	2.4%	2.5%
Other	6.1%	6.3%	5.9%	5.4%	5.9%	5.6%

AFUDC

AFUDC represents costs to finance construction additions, including a return on equity component and cost of debt component as required by regulatory accounting. AFUDC for IPL’s construction projects is calculated in accordance with FERC guidelines. AFUDC for WPL’s retail and wholesale jurisdiction construction projects is calculated in accordance with PSCW and FERC guidelines, respectively. The AFUDC rates, computed in accordance with the prescribed regulatory formula, were as follows:

	2021	2020	2019
IPL (Wind generation CWIP)	7.0%	7.1%	7.4%
IPL (other CWIP)	7.2%	7.2%	7.5%
WPL (retail jurisdiction)	7.0%	7.0%	6.8%
WPL (wholesale jurisdiction)	5.6%	6.3%	6.9%

In accordance with their respective regulatory commission decisions, IPL applies its AFUDC rates to 100% of applicable CWIP balances and WPL generally applies its AFUDC rates to 50% of applicable CWIP balances. WPL may apply its AFUDC rates to 100% of the retail portion of the CWIP balances for construction projects requiring a CA or CPCN that were approved by the PSCW after its then most recent rate order, including West Riverside and the first and second solar generation CAs.

Revenue Recognition

Utility - Revenues from Alliant Energy’s utility business are primarily from electric and gas sales to customers. Utility revenues are recognized over time as services are rendered or commodities are delivered to customers, and include billed and unbilled components. The billed component is based on the reading of customers’ meters, which occurs on a systematic basis throughout each reporting period and represents the fair value of the services provided or commodities delivered. The unbilled component is estimated and recorded at the end of each reporting period based on estimated amounts of energy delivered to customers since the end of each customer’s last billing period. The unbilled component is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates.

IPL and WPL accrue revenues from their wholesale customers to the extent that the actual net revenue requirements calculated in accordance with FERC-approved formula rates for the reporting period are higher or lower than the amounts billed to wholesale customers during such period. Regulatory assets or regulatory liabilities are recorded as the offset for these accrued revenues under formulaic rate-making programs. As of December 31, 2021, the related amounts accrued for IPL and WPL were not material.

IPL and WPL participate in bid/offer-based wholesale energy and ancillary services markets operated by MISO. The MISO transactions are grouped together, resulting in a net supply to or net purchase from MISO for each hour of each day. The net supply to MISO is recorded as bulk power sales in “Electric utility revenues” and the net purchase from MISO is recorded in “Electric production fuel and purchased power” in the income statements.

Non-utility - Revenues from Alliant Energy’s non-utility businesses are primarily from its Travero business and are recognized over time as services are rendered to customers.

Taxes Collected from Customers - Sales or various other taxes collected by certain of Alliant Energy’s subsidiaries on behalf of other agencies are recorded on a net basis and are not included in revenues.

Other - Alliant Energy, IPL and WPL do not disclose the value of unsatisfied performance obligations for: (i) contracts with an original expected length of one year or less; and (ii) contracts for which revenue is recognized at the amount to which they have the right to invoice for services performed.

Utility Cost Recovery Mechanisms

Electric Production Fuel and Purchased Power (Fuel-related Costs) - Fuel-related costs are incurred to generate and purchase electricity to meet the demand of IPL’s and WPL’s electric customers. These fuel-related costs include the cost of fossil fuels (primarily natural gas and coal) used to produce electricity at their EGUs, and electricity purchased from MISO wholesale energy markets and under PPAs. These fuel-related costs are recorded in “Electric production fuel and purchased power” in the income statements.

IPL Retail - The cost recovery mechanisms for IPL’s retail electric customers provide for monthly adjustments to their electric rates for changes in fuel-related costs. Changes in the under-/over-collection of these costs are recognized in “Electric production fuel and purchased power” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

WPL Retail - The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. If WPL’s actual fuel-related costs fall outside these fuel monitoring ranges, WPL is authorized to defer the incremental under-/over-collection of fuel-related costs that are outside the approved ranges. Deferral of under-collections are reduced to the extent actual return on common equity earned by WPL during the fuel cost plan year exceeds the most recently authorized return on common equity. Deferred amounts for fuel-related costs outside the approved fuel monitoring ranges are recognized in “Electric production fuel and purchased power” in Alliant Energy’s and WPL’s income statements. The cumulative effects of these deferred amounts are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and WPL’s balance sheets until they are reflected in future billings to customers.

IPL and WPL Wholesale - The cost recovery mechanisms for IPL’s and WPL’s wholesale electric customers provide for subsequent adjustments to their electric rates for changes in fuel-related costs. Changes in the under-/over-collection of these costs are recognized in “Electric production fuel and purchased power” in the income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Purchased Electric Capacity - PPAs help meet the electricity demand of IPL’s and WPL’s customers. Certain PPAs include minimum payments for IPL’s and WPL’s rights to electric generating capacity, which are charged each period to “Electric production fuel and purchased power” in the income statements. Purchased electric capacity expenses are recovered from IPL’s and WPL’s retail electric customers through changes in base rates determined during periodic rate proceedings. Purchased electric capacity expenses are recovered from IPL’s and WPL’s wholesale electric customers through annual changes in base rates determined by a formula rate structure.

Electric Transmission Service - Costs incurred for the transmission of electricity to meet the demands of IPL’s and WPL’s customers are charged to “Electric transmission service” in the income statements.

IPL Retail - Electric transmission service expense is recovered from IPL’s retail electric customers through a transmission cost rider. This cost recovery mechanism provides for periodic adjustments to electric rates charged to retail electric customers for changes in electric transmission service expense. Changes in the under-/over-collection of these costs are recognized in “Electric transmission service” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

WPL Retail - Electric transmission service expense is recovered from WPL’s retail electric customers through changes in base rates determined during periodic rate proceedings. Pursuant to escrow accounting treatment approved by the PSCW, the difference between actual electric transmission service expense incurred and the amount of electric transmission service costs collected from customers as electric revenues is recognized in “Electric transmission service” in Alliant Energy’s and WPL’s income statements. An offsetting amount is recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and WPL’s balance sheets until reflected in future billings to customers.

IPL and WPL Wholesale - IPL and WPL arrange transmission service for the majority of their respective wholesale electric customers. Electric transmission service expense is allocated to and recovered from these customers based on a load ratio share computation.

Cost of Gas Sold - Costs are incurred for the purchase, transportation and storage of natural gas to serve IPL’s and WPL’s gas customers and the costs associated with the natural gas delivered to customers are charged to “Cost of gas sold” in the income statements. The tariffs for IPL’s and WPL’s retail gas customers provide for subsequent adjustments to their rates periodically for changes in the cost of gas sold. Changes in the under-/over-collection of these costs are also recognized in “Cost of gas sold” in the income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Energy Efficiency Costs - Costs incurred to fund energy efficiency programs and initiatives that help customers reduce their energy usage are charged to “Other operation and maintenance” in the income statements. Energy efficiency costs incurred by IPL are recovered from its retail electric and gas customers through energy efficiency and demand response cost recovery factor tariffs, which are revised annually and include a reconciliation to eliminate any under-/over-collection of energy efficiency costs from prior periods. Energy efficiency costs incurred by WPL are recovered from retail electric and gas customers through changes in base rates determined during periodic rate proceedings. Reconciliations of any under-/over-collection of energy efficiency costs from prior periods are also addressed in WPL’s periodic rate proceedings. Changes in the under-/over-collection of energy efficiency costs for IPL and WPL are recognized in “Other operation and maintenance” in the income statements. The cumulative effects of the under-/over-collection of these costs for IPL and WPL are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Renewable Energy Rider - Effective with the implementation of final rates covering the 2020 forward-looking Test Period, IPL recovers a return of, as well as earn a return on, its new wind generation placed in service in 2019 and 2020 from its retail electric customers through a renewable energy rider. Other applicable costs and tax benefits associated with the new wind generation, excluding operation and maintenance expenses, are also included in the rider. This cost recovery mechanism provides for annual adjustments to electric rates charged to IPL’s retail electric customers for actual renewable energy costs and tax benefits. Changes in the under-/over-collection of these costs are recognized in “Electric utility revenue” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs for IPL are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

Financial Instruments

Financial instruments are periodically used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. The fair value of those financial instruments that are determined to be derivatives are recorded as assets or liabilities on the balance sheets. Certain commodity purchase and sales contracts qualified for and were designated under the normal purchase and sale exception, and were accounted for on the accrual basis of accounting. Alliant Energy, IPL and WPL have elected to not net the fair value amounts of derivatives subject to a master netting arrangement by counterparty. Alliant Energy, IPL and WPL do not offset fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) against fair value amounts recognized for derivative instruments that are executed with the same counterparty under the same master netting arrangement.

Asset Impairments

Property, Plant and Equipment of Regulated Operations - Property, plant and equipment of regulated operations are reviewed for possible impairment whenever events or changes in circumstances indicate all or a portion of the carrying value of the assets may be disallowed for rate-making purposes. If IPL or WPL are disallowed recovery of any portion of, or are only allowed a partial return on, the carrying value of their regulated property, plant and equipment that is under construction, has been recently completed or is probable of abandonment, or conclude it is probable recovery or a full return will be disallowed, then an impairment charge is recognized.

Property, Plant and Equipment of Non-utility Operations - Property, plant and equipment of non-utility operations are reviewed for possible impairment whenever events or changes in circumstances indicate the carrying value of the assets may not be recoverable. Impairment is indicated if the carrying value of an asset exceeds its undiscounted future cash flows. If an impairment is indicated, a charge is recognized equal to the amount the carrying value exceeds the asset’s fair value.

Unconsolidated Equity Investments - If events or circumstances indicate the carrying value of investments accounted for under the equity method of accounting exceeds fair value and the decline in value is other than temporary, potential impairment is assessed. If an impairment is indicated, a charge is recognized equal to the amount the carrying value exceeds the investment’s fair value.

Asset Retirement Obligations

The fair value of a legal obligation associated with the retirement of an asset is recorded as a liability when an asset is placed in service, when a legal obligation is subsequently identified or when sufficient information becomes available to determine a reasonable estimate of the fair value of future retirement costs. When an ARO is recorded as a liability, an equivalent amount is added to the asset cost. The fair value of AROs at inception is determined using discounted cash flows analyses. The liability is accreted to its present value and the capitalized cost is depreciated over the useful life of the related asset. Accretion and depreciation expenses related to AROs for IPL’s and WPL’s regulated operations are recorded to regulatory assets on the balance sheets. Revisions in estimated cash flows for IPL’s and WPL’s regulated operations are recorded as an increase or decrease to the ARO liability, with an offset to the asset cost, unless the asset is already retired and then the offset is recorded to regulatory assets or regulatory liabilities on the balance sheets. Upon regulatory approval to recover IPL’s AROs expenditures, its regulatory assets are amortized to depreciation and amortization expenses in Alliant Energy’s and IPL’s income statements over the same time period the ARO expenditures are recovered from IPL’s customers. WPL’s regulatory assets related to AROs are recovered as a component of depreciation rates pursuant to PSCW and FERC orders. Upon settlement of the ARO liability, an entity settles the obligation for its recorded amount or incurs a gain or loss. Any gains or losses related to AROs for IPL’s and WPL’s regulated operations are recorded to regulatory liabilities or regulatory assets on the balance sheets.

Debt Issuance and Retirement Costs

Debt issuance costs and debt premiums or discounts are presented on the balance sheets as a direct adjustment to the carrying amount of the related debt liability, and are deferred and amortized over the expected life of each debt issue, considering maturity dates and, if applicable, redemption rights held by others. Alliant Energy’s non-utility businesses and Corporate Services record to interest expense in the period of retirement any unamortized debt issuance costs and debt premiums or discounts on debt retired early.

Current Expected Credit Losses Estimates

Current expected credit losses are estimated for trade and other receivables and credit exposures on guarantees of the performance by third parties. The current expected credit losses for short-term trade receivables are based on estimates of losses resulting from the inability of customers to make required payments. The methodology used to estimate losses is based on historical write-offs, regional economic conditions, significant events that could impact collectability, such as impacts related to COVID-19, significant weather related matters including the derecho windstorm and related regulatory actions, and forecasted changes to the accounts receivable aging portfolio and write-offs. The current expected credit losses related to guarantees of the performance by third parties are estimated using both quantitative and qualitative information, which utilizes potential outcomes in a range of possible estimated amounts.In 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 17(d) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s equity statement for 2020.

Variable Interest Entities

An entity is considered a VIE if its equity investors do not have sufficient equity at risk for the entity to finance its activities without additional subordinated financial support from other parties, the entity is structured with disproportionate voting rights and substantially all of the entity’s activities are conducted on behalf of the investor with disproportionately fewer voting rights, or its equity investors lack any of the following characteristics: (1) power, through voting rights or similar rights, to direct the activities of the entity that most significantly impact the entity’s economic performance; (2) the obligation to absorb expected losses of the entity; or (3) the right to receive expected benefits of the entity. The primary beneficiary of a VIE is required to consolidate the VIE. The financial statements do not reflect any consolidation of VIEs.

Leases

The determination of whether an arrangement qualifies as a lease occurs at the inception of the arrangement. Arrangements that qualify as leases are classified as either operating or finance. Operating and finance lease liabilities represent obligations to make payments arising from the lease. Operating and finance lease assets represent the right to use an underlying asset for the lease term and are recognized at the lease commencement date based on the present value of the lease payments over the lease term. Leases with initial terms less than 12 months are not recognized as leases. For operating leases, an incremental borrowing rate, as determined at the lease commencement date, is used to determine the present value of the lease payments. For finance leases, the rate implicit in the lease, if known, is used to determine the present value of the lease payments. If the rate implicit in the lease is not known, the incremental borrowing rate is used to determine the present value of the lease payments. Lease terms include options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Operating lease expense is recognized on a straight-line basis over the expected lease term. Finance lease expense is comprised of depreciation and amortization, and interest expenses. Finance lease assets related to leased land for solar generation are amortized on a straight-line basis over the lease term, and are accounted for as operating leases for rate-making purposes. All other finance lease assets are depreciated on a straight-line basis over the shorter of the useful life of the underlying asset or the lease term.

IPL [Member]

Property, Plant and Equipment [Line Items]

General, Basis of Presentation

The financial statements reflect investments in controlled subsidiaries on a consolidated basis and Alliant Energy’s, IPL’s and WPL’s proportionate shares of jointly-owned utility EGUs. Unconsolidated investments that Alliant Energy and WPL do not control are accounted for under the equity method of accounting. Under the equity method of accounting, Alliant Energy and WPL initially record the investment at cost, and adjust the carrying amount of the investment to recognize their respective share of the earnings or losses of the investee. Dividends received from an investee reduce the carrying amount of the equity investment. Investments that do not meet the criteria for consolidation or the equity method of accounting are accounted for under the cost method.All intercompany balances and transactions, other than certain transactions affecting the rate-making process at IPL and WPL, have been eliminated from the financial statements. Such transactions not eliminated include costs that are recoverable from customers through rate-making processes.

General, Basis of Accounting

The financial statements are prepared in conformity with GAAP, which give recognition to the rate-making practices of FERC and state commissions having regulatory jurisdiction.

General, Reclassification

Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.

General, Use of Estimates

The preparation of the financial statements requires management to make estimates and assumptions that affect: (a) the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements; and (b) the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

Regulatory Assets and Regulatory Liabilities

Alliant Energy, IPL and WPL are subject to regulation by FERC and various state regulatory commissions. As a result, Alliant Energy, IPL and WPL are subject to GAAP provisions for regulated operations, which provide that rate-regulated public utilities record certain costs and credits allowed in the rate-making process in different periods than for non-utility entities. Regulatory assets generally represent incurred costs that have been deferred as such costs are probable of recovery in future customer rates. Regulatory liabilities generally represent obligations to make refunds to customers or amounts collected in rates for which the related costs have not yet been incurred. Amounts recorded as regulatory assets or regulatory liabilities are generally recognized in the income statements at the time they are reflected in rates.

Income Taxes

The liability method of accounting is followed for deferred taxes, which requires the establishment of deferred tax assets and liabilities, as appropriate, for temporary differences between the tax basis of assets and liabilities and the amounts reported in the financial statements. Deferred taxes are recorded using currently enacted tax rates and estimates of state apportionment. Changes in deferred tax assets and liabilities associated with certain property-related differences at IPL are accounted for differently than other subsidiaries of Alliant Energy due to rate-making practices in Iowa. Rate-making practices in Iowa do not allow the impact of certain deferred tax expenses (benefits) to be included in the determination of retail rates. Based on these rate-making practices, deferred tax expense (benefit) related to these property-related differences at IPL is not recorded in the income statement but instead recorded to regulatory assets or regulatory liabilities until these temporary differences reverse. In Wisconsin, the PSCW allows rate recovery of deferred tax expense on all temporary differences.

Investment tax credits are deferred and amortized to income over the average lives of the related property. Federal Tax Reform repealed corporate federal alternative minimum tax and allowed unutilized alternative minimum tax credits to be refunded over four tax years beginning with the U.S. federal tax return for calendar year 2018. Pursuant to the Coronavirus Aid, Relief, and Economic Security Act, Alliant Energy received the remaining alternative minimum tax credits refunds in 2020. Other tax credits reduce income tax expense in the year claimed.

Alliant Energy files a consolidated federal income tax return and a combined return in Wisconsin, which include Alliant Energy and its subsidiaries. Alliant Energy subsidiaries with a presence in Iowa file as part of a consolidated return in Iowa.

Alliant Energy allocates consolidated income tax expense to its subsidiaries that are members of the group that file a consolidated or combined income tax return. IPL and WPL use the modified separate return approach for calculating their income tax provisions and related deferred tax assets and liabilities. IPL and WPL are assumed to file separate tax returns with the federal and state taxing authorities, except that net operating losses (and other current or deferred tax attributes) are characterized as realized (or realizable) by IPL and WPL when those tax attributes are realized (or realizable) by the consolidated tax return group of Alliant Energy (even if IPL and WPL would not otherwise have realized the attributes on a stand-alone basis). The difference in the income taxes recorded for IPL and WPL under the modified separate return method compared to the income taxes recorded on a separate return basis was not material in 2021, 2020 and 2019.

Cash, Cash Equivalents and Restricted Cash

Cash and cash equivalents include short-term liquid investments that have original maturities of less than 90 days. At December 31, 2021, Alliant Energy’s and IPL’s cash and cash equivalents included $32 million of money market fund investments, with an interest rate of 0.04%. At December 31, 2021 and 2020, Alliant Energy’s restricted cash related to requirements in Sheboygan Power, LLC’s debt agreement.

Property, Plant and Equipment

Utility Plant -

General - Utility plant is recorded at the original cost of acquisition or construction, which includes material, labor, contractor services, AFUDC and allocable overheads, such as supervision, engineering, benefits, certain taxes and transportation. Repairs, replacements and renewals of items of property determined to be less than a unit of property or that do not increase the property’s life or functionality are charged to maintenance expense. Property, plant and equipment that is probable of being retired early is classified as plant anticipated to be retired early. Generally, ordinary retirements of utility plant and salvage value are netted and charged to accumulated depreciation upon removal from utility plant accounts and no gain or loss is recognized consistent with rate-making principles. However, if regulators have approved recovery of the remaining net book value of property, plant and equipment that is retired early, or such approval by regulators is probable, the remaining net book value is reclassified from property, plant and equipment to regulatory assets upon retirement.

Non-utility and Other Property -

General - Non-utility property is recorded at the original cost of acquisition or construction, which includes material, labor and contractor services. Repairs, replacements and renewals of items of property determined to be less than a unit of property or that do not increase the property’s life or functionality are charged to maintenance expense. Upon retirement or sale of non-utility property, the original cost and related accumulated depreciation are removed from the accounts and any gain or loss is included in the income statements.

Costs related to software developed or obtained for internal use are capitalized and amortized on a straight-line basis over the estimated useful life of the related software. If software is retired prior to being fully amortized, the remaining book value is recorded as a loss in the income statements.

Depreciation

IPL and WPL use a combination of remaining life and straight-line depreciation methods as approved by their respective regulatory commissions. The composite or group method of depreciation is used, in which a single depreciation rate is applied to the gross investment in a particular class of property. This method pools similar assets and then depreciates each group as a whole. Periodic depreciation studies are performed to determine the appropriate group lives, net salvage, estimated cost of removal and group depreciation rates. These depreciation studies are subject to review and approval by IPL’s and WPL’s respective regulatory commissions. Depreciation expense is included within the recoverable cost of service component of rates collected from customers. The average rates of depreciation for electric, gas and other properties, consistent with current rate-making practices, were as follows:

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Electric - generation	3.4%	3.5%	3.8%	3.5%	3.5%	3.6%
Electric - distribution	2.9%	2.8%	2.9%	2.6%	2.6%	2.6%
Electric - other	5.7%	5.2%	5.3%	7.4%	6.1%	5.8%
Gas	3.3%	3.3%	3.3%	2.4%	2.4%	2.5%
Other	6.1%	6.3%	5.9%	5.4%	5.9%	5.6%

AFUDC

AFUDC represents costs to finance construction additions, including a return on equity component and cost of debt component as required by regulatory accounting. AFUDC for IPL’s construction projects is calculated in accordance with FERC guidelines. AFUDC for WPL’s retail and wholesale jurisdiction construction projects is calculated in accordance with PSCW and FERC guidelines, respectively. The AFUDC rates, computed in accordance with the prescribed regulatory formula, were as follows:

	2021	2020	2019
IPL (Wind generation CWIP)	7.0%	7.1%	7.4%
IPL (other CWIP)	7.2%	7.2%	7.5%
WPL (retail jurisdiction)	7.0%	7.0%	6.8%
WPL (wholesale jurisdiction)	5.6%	6.3%	6.9%

In accordance with their respective regulatory commission decisions, IPL applies its AFUDC rates to 100% of applicable CWIP balances and WPL generally applies its AFUDC rates to 50% of applicable CWIP balances. WPL may apply its AFUDC rates to 100% of the retail portion of the CWIP balances for construction projects requiring a CA or CPCN that were approved by the PSCW after its then most recent rate order, including West Riverside and the first and second solar generation CAs.

Revenue Recognition

Utility - Revenues from Alliant Energy’s utility business are primarily from electric and gas sales to customers. Utility revenues are recognized over time as services are rendered or commodities are delivered to customers, and include billed and unbilled components. The billed component is based on the reading of customers’ meters, which occurs on a systematic basis throughout each reporting period and represents the fair value of the services provided or commodities delivered. The unbilled component is estimated and recorded at the end of each reporting period based on estimated amounts of energy delivered to customers since the end of each customer’s last billing period. The unbilled component is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates.

IPL and WPL accrue revenues from their wholesale customers to the extent that the actual net revenue requirements calculated in accordance with FERC-approved formula rates for the reporting period are higher or lower than the amounts billed to wholesale customers during such period. Regulatory assets or regulatory liabilities are recorded as the offset for these accrued revenues under formulaic rate-making programs. As of December 31, 2021, the related amounts accrued for IPL and WPL were not material.

IPL and WPL participate in bid/offer-based wholesale energy and ancillary services markets operated by MISO. The MISO transactions are grouped together, resulting in a net supply to or net purchase from MISO for each hour of each day. The net supply to MISO is recorded as bulk power sales in “Electric utility revenues” and the net purchase from MISO is recorded in “Electric production fuel and purchased power” in the income statements.

Non-utility - Revenues from Alliant Energy’s non-utility businesses are primarily from its Travero business and are recognized over time as services are rendered to customers.

Taxes Collected from Customers - Sales or various other taxes collected by certain of Alliant Energy’s subsidiaries on behalf of other agencies are recorded on a net basis and are not included in revenues.

Other - Alliant Energy, IPL and WPL do not disclose the value of unsatisfied performance obligations for: (i) contracts with an original expected length of one year or less; and (ii) contracts for which revenue is recognized at the amount to which they have the right to invoice for services performed.

Utility Cost Recovery Mechanisms

Electric Production Fuel and Purchased Power (Fuel-related Costs) - Fuel-related costs are incurred to generate and purchase electricity to meet the demand of IPL’s and WPL’s electric customers. These fuel-related costs include the cost of fossil fuels (primarily natural gas and coal) used to produce electricity at their EGUs, and electricity purchased from MISO wholesale energy markets and under PPAs. These fuel-related costs are recorded in “Electric production fuel and purchased power” in the income statements.

IPL Retail - The cost recovery mechanisms for IPL’s retail electric customers provide for monthly adjustments to their electric rates for changes in fuel-related costs. Changes in the under-/over-collection of these costs are recognized in “Electric production fuel and purchased power” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

WPL Retail - The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. If WPL’s actual fuel-related costs fall outside these fuel monitoring ranges, WPL is authorized to defer the incremental under-/over-collection of fuel-related costs that are outside the approved ranges. Deferral of under-collections are reduced to the extent actual return on common equity earned by WPL during the fuel cost plan year exceeds the most recently authorized return on common equity. Deferred amounts for fuel-related costs outside the approved fuel monitoring ranges are recognized in “Electric production fuel and purchased power” in Alliant Energy’s and WPL’s income statements. The cumulative effects of these deferred amounts are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and WPL’s balance sheets until they are reflected in future billings to customers.

IPL and WPL Wholesale - The cost recovery mechanisms for IPL’s and WPL’s wholesale electric customers provide for subsequent adjustments to their electric rates for changes in fuel-related costs. Changes in the under-/over-collection of these costs are recognized in “Electric production fuel and purchased power” in the income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Purchased Electric Capacity - PPAs help meet the electricity demand of IPL’s and WPL’s customers. Certain PPAs include minimum payments for IPL’s and WPL’s rights to electric generating capacity, which are charged each period to “Electric production fuel and purchased power” in the income statements. Purchased electric capacity expenses are recovered from IPL’s and WPL’s retail electric customers through changes in base rates determined during periodic rate proceedings. Purchased electric capacity expenses are recovered from IPL’s and WPL’s wholesale electric customers through annual changes in base rates determined by a formula rate structure.

Electric Transmission Service - Costs incurred for the transmission of electricity to meet the demands of IPL’s and WPL’s customers are charged to “Electric transmission service” in the income statements.

IPL Retail - Electric transmission service expense is recovered from IPL’s retail electric customers through a transmission cost rider. This cost recovery mechanism provides for periodic adjustments to electric rates charged to retail electric customers for changes in electric transmission service expense. Changes in the under-/over-collection of these costs are recognized in “Electric transmission service” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

WPL Retail - Electric transmission service expense is recovered from WPL’s retail electric customers through changes in base rates determined during periodic rate proceedings. Pursuant to escrow accounting treatment approved by the PSCW, the difference between actual electric transmission service expense incurred and the amount of electric transmission service costs collected from customers as electric revenues is recognized in “Electric transmission service” in Alliant Energy’s and WPL’s income statements. An offsetting amount is recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and WPL’s balance sheets until reflected in future billings to customers.

IPL and WPL Wholesale - IPL and WPL arrange transmission service for the majority of their respective wholesale electric customers. Electric transmission service expense is allocated to and recovered from these customers based on a load ratio share computation.

Cost of Gas Sold - Costs are incurred for the purchase, transportation and storage of natural gas to serve IPL’s and WPL’s gas customers and the costs associated with the natural gas delivered to customers are charged to “Cost of gas sold” in the income statements. The tariffs for IPL’s and WPL’s retail gas customers provide for subsequent adjustments to their rates periodically for changes in the cost of gas sold. Changes in the under-/over-collection of these costs are also recognized in “Cost of gas sold” in the income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Energy Efficiency Costs - Costs incurred to fund energy efficiency programs and initiatives that help customers reduce their energy usage are charged to “Other operation and maintenance” in the income statements. Energy efficiency costs incurred by IPL are recovered from its retail electric and gas customers through energy efficiency and demand response cost recovery factor tariffs, which are revised annually and include a reconciliation to eliminate any under-/over-collection of energy efficiency costs from prior periods. Energy efficiency costs incurred by WPL are recovered from retail electric and gas customers through changes in base rates determined during periodic rate proceedings. Reconciliations of any under-/over-collection of energy efficiency costs from prior periods are also addressed in WPL’s periodic rate proceedings. Changes in the under-/over-collection of energy efficiency costs for IPL and WPL are recognized in “Other operation and maintenance” in the income statements. The cumulative effects of the under-/over-collection of these costs for IPL and WPL are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Renewable Energy Rider - Effective with the implementation of final rates covering the 2020 forward-looking Test Period, IPL recovers a return of, as well as earn a return on, its new wind generation placed in service in 2019 and 2020 from its retail electric customers through a renewable energy rider. Other applicable costs and tax benefits associated with the new wind generation, excluding operation and maintenance expenses, are also included in the rider. This cost recovery mechanism provides for annual adjustments to electric rates charged to IPL’s retail electric customers for actual renewable energy costs and tax benefits. Changes in the under-/over-collection of these costs are recognized in “Electric utility revenue” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs for IPL are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

Financial Instruments

Financial instruments are periodically used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. The fair value of those financial instruments that are determined to be derivatives are recorded as assets or liabilities on the balance sheets. Certain commodity purchase and sales contracts qualified for and were designated under the normal purchase and sale exception, and were accounted for on the accrual basis of accounting. Alliant Energy, IPL and WPL have elected to not net the fair value amounts of derivatives subject to a master netting arrangement by counterparty. Alliant Energy, IPL and WPL do not offset fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) against fair value amounts recognized for derivative instruments that are executed with the same counterparty under the same master netting arrangement.

Asset Impairments

Property, Plant and Equipment of Regulated Operations - Property, plant and equipment of regulated operations are reviewed for possible impairment whenever events or changes in circumstances indicate all or a portion of the carrying value of the assets may be disallowed for rate-making purposes. If IPL or WPL are disallowed recovery of any portion of, or are only allowed a partial return on, the carrying value of their regulated property, plant and equipment that is under construction, has been recently completed or is probable of abandonment, or conclude it is probable recovery or a full return will be disallowed, then an impairment charge is recognized.

Property, Plant and Equipment of Non-utility Operations - Property, plant and equipment of non-utility operations are reviewed for possible impairment whenever events or changes in circumstances indicate the carrying value of the assets may not be recoverable. Impairment is indicated if the carrying value of an asset exceeds its undiscounted future cash flows. If an impairment is indicated, a charge is recognized equal to the amount the carrying value exceeds the asset’s fair value.

Unconsolidated Equity Investments - If events or circumstances indicate the carrying value of investments accounted for under the equity method of accounting exceeds fair value and the decline in value is other than temporary, potential impairment is assessed. If an impairment is indicated, a charge is recognized equal to the amount the carrying value exceeds the investment’s fair value.

Asset Retirement Obligations

The fair value of a legal obligation associated with the retirement of an asset is recorded as a liability when an asset is placed in service, when a legal obligation is subsequently identified or when sufficient information becomes available to determine a reasonable estimate of the fair value of future retirement costs. When an ARO is recorded as a liability, an equivalent amount is added to the asset cost. The fair value of AROs at inception is determined using discounted cash flows analyses. The liability is accreted to its present value and the capitalized cost is depreciated over the useful life of the related asset. Accretion and depreciation expenses related to AROs for IPL’s and WPL’s regulated operations are recorded to regulatory assets on the balance sheets. Revisions in estimated cash flows for IPL’s and WPL’s regulated operations are recorded as an increase or decrease to the ARO liability, with an offset to the asset cost, unless the asset is already retired and then the offset is recorded to regulatory assets or regulatory liabilities on the balance sheets. Upon regulatory approval to recover IPL’s AROs expenditures, its regulatory assets are amortized to depreciation and amortization expenses in Alliant Energy’s and IPL’s income statements over the same time period the ARO expenditures are recovered from IPL’s customers. WPL’s regulatory assets related to AROs are recovered as a component of depreciation rates pursuant to PSCW and FERC orders. Upon settlement of the ARO liability, an entity settles the obligation for its recorded amount or incurs a gain or loss. Any gains or losses related to AROs for IPL’s and WPL’s regulated operations are recorded to regulatory liabilities or regulatory assets on the balance sheets.

Debt Issuance and Retirement Costs

Debt issuance costs and debt premiums or discounts are presented on the balance sheets as a direct adjustment to the carrying amount of the related debt liability, and are deferred and amortized over the expected life of each debt issue, considering maturity dates and, if applicable, redemption rights held by others. Alliant Energy’s non-utility businesses and Corporate Services record to interest expense in the period of retirement any unamortized debt issuance costs and debt premiums or discounts on debt retired early.

Current Expected Credit Losses Estimates

Current expected credit losses are estimated for trade and other receivables and credit exposures on guarantees of the performance by third parties. The current expected credit losses for short-term trade receivables are based on estimates of losses resulting from the inability of customers to make required payments. The methodology used to estimate losses is based on historical write-offs, regional economic conditions, significant events that could impact collectability, such as impacts related to COVID-19, significant weather related matters including the derecho windstorm and related regulatory actions, and forecasted changes to the accounts receivable aging portfolio and write-offs. The current expected credit losses related to guarantees of the performance by third parties are estimated using both quantitative and qualitative information, which utilizes potential outcomes in a range of possible estimated amounts.In 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 17(d) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s equity statement for 2020.

Variable Interest Entities

An entity is considered a VIE if its equity investors do not have sufficient equity at risk for the entity to finance its activities without additional subordinated financial support from other parties, the entity is structured with disproportionate voting rights and substantially all of the entity’s activities are conducted on behalf of the investor with disproportionately fewer voting rights, or its equity investors lack any of the following characteristics: (1) power, through voting rights or similar rights, to direct the activities of the entity that most significantly impact the entity’s economic performance; (2) the obligation to absorb expected losses of the entity; or (3) the right to receive expected benefits of the entity. The primary beneficiary of a VIE is required to consolidate the VIE. The financial statements do not reflect any consolidation of VIEs.

Leases

The determination of whether an arrangement qualifies as a lease occurs at the inception of the arrangement. Arrangements that qualify as leases are classified as either operating or finance. Operating and finance lease liabilities represent obligations to make payments arising from the lease. Operating and finance lease assets represent the right to use an underlying asset for the lease term and are recognized at the lease commencement date based on the present value of the lease payments over the lease term. Leases with initial terms less than 12 months are not recognized as leases. For operating leases, an incremental borrowing rate, as determined at the lease commencement date, is used to determine the present value of the lease payments. For finance leases, the rate implicit in the lease, if known, is used to determine the present value of the lease payments. If the rate implicit in the lease is not known, the incremental borrowing rate is used to determine the present value of the lease payments. Lease terms include options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Operating lease expense is recognized on a straight-line basis over the expected lease term. Finance lease expense is comprised of depreciation and amortization, and interest expenses. Finance lease assets related to leased land for solar generation are amortized on a straight-line basis over the lease term, and are accounted for as operating leases for rate-making purposes. All other finance lease assets are depreciated on a straight-line basis over the shorter of the useful life of the underlying asset or the lease term.

WPL [Member]

Property, Plant and Equipment [Line Items]

General, Basis of Presentation

The financial statements reflect investments in controlled subsidiaries on a consolidated basis and Alliant Energy’s, IPL’s and WPL’s proportionate shares of jointly-owned utility EGUs. Unconsolidated investments that Alliant Energy and WPL do not control are accounted for under the equity method of accounting. Under the equity method of accounting, Alliant Energy and WPL initially record the investment at cost, and adjust the carrying amount of the investment to recognize their respective share of the earnings or losses of the investee. Dividends received from an investee reduce the carrying amount of the equity investment. Investments that do not meet the criteria for consolidation or the equity method of accounting are accounted for under the cost method.All intercompany balances and transactions, other than certain transactions affecting the rate-making process at IPL and WPL, have been eliminated from the financial statements. Such transactions not eliminated include costs that are recoverable from customers through rate-making processes.

General, Basis of Accounting

The financial statements are prepared in conformity with GAAP, which give recognition to the rate-making practices of FERC and state commissions having regulatory jurisdiction.

General, Reclassification

Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.

General, Use of Estimates

The preparation of the financial statements requires management to make estimates and assumptions that affect: (a) the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements; and (b) the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

Regulatory Assets and Regulatory Liabilities

Alliant Energy, IPL and WPL are subject to regulation by FERC and various state regulatory commissions. As a result, Alliant Energy, IPL and WPL are subject to GAAP provisions for regulated operations, which provide that rate-regulated public utilities record certain costs and credits allowed in the rate-making process in different periods than for non-utility entities. Regulatory assets generally represent incurred costs that have been deferred as such costs are probable of recovery in future customer rates. Regulatory liabilities generally represent obligations to make refunds to customers or amounts collected in rates for which the related costs have not yet been incurred. Amounts recorded as regulatory assets or regulatory liabilities are generally recognized in the income statements at the time they are reflected in rates.

Income Taxes

The liability method of accounting is followed for deferred taxes, which requires the establishment of deferred tax assets and liabilities, as appropriate, for temporary differences between the tax basis of assets and liabilities and the amounts reported in the financial statements. Deferred taxes are recorded using currently enacted tax rates and estimates of state apportionment. Changes in deferred tax assets and liabilities associated with certain property-related differences at IPL are accounted for differently than other subsidiaries of Alliant Energy due to rate-making practices in Iowa. Rate-making practices in Iowa do not allow the impact of certain deferred tax expenses (benefits) to be included in the determination of retail rates. Based on these rate-making practices, deferred tax expense (benefit) related to these property-related differences at IPL is not recorded in the income statement but instead recorded to regulatory assets or regulatory liabilities until these temporary differences reverse. In Wisconsin, the PSCW allows rate recovery of deferred tax expense on all temporary differences.

Investment tax credits are deferred and amortized to income over the average lives of the related property. Federal Tax Reform repealed corporate federal alternative minimum tax and allowed unutilized alternative minimum tax credits to be refunded over four tax years beginning with the U.S. federal tax return for calendar year 2018. Pursuant to the Coronavirus Aid, Relief, and Economic Security Act, Alliant Energy received the remaining alternative minimum tax credits refunds in 2020. Other tax credits reduce income tax expense in the year claimed.

Alliant Energy files a consolidated federal income tax return and a combined return in Wisconsin, which include Alliant Energy and its subsidiaries. Alliant Energy subsidiaries with a presence in Iowa file as part of a consolidated return in Iowa.

Alliant Energy allocates consolidated income tax expense to its subsidiaries that are members of the group that file a consolidated or combined income tax return. IPL and WPL use the modified separate return approach for calculating their income tax provisions and related deferred tax assets and liabilities. IPL and WPL are assumed to file separate tax returns with the federal and state taxing authorities, except that net operating losses (and other current or deferred tax attributes) are characterized as realized (or realizable) by IPL and WPL when those tax attributes are realized (or realizable) by the consolidated tax return group of Alliant Energy (even if IPL and WPL would not otherwise have realized the attributes on a stand-alone basis). The difference in the income taxes recorded for IPL and WPL under the modified separate return method compared to the income taxes recorded on a separate return basis was not material in 2021, 2020 and 2019.

Cash, Cash Equivalents and Restricted Cash

Cash and cash equivalents include short-term liquid investments that have original maturities of less than 90 days. At December 31, 2021, Alliant Energy’s and IPL’s cash and cash equivalents included $32 million of money market fund investments, with an interest rate of 0.04%. At December 31, 2021 and 2020, Alliant Energy’s restricted cash related to requirements in Sheboygan Power, LLC’s debt agreement.

Property, Plant and Equipment

Utility Plant -

General - Utility plant is recorded at the original cost of acquisition or construction, which includes material, labor, contractor services, AFUDC and allocable overheads, such as supervision, engineering, benefits, certain taxes and transportation. Repairs, replacements and renewals of items of property determined to be less than a unit of property or that do not increase the property’s life or functionality are charged to maintenance expense. Property, plant and equipment that is probable of being retired early is classified as plant anticipated to be retired early. Generally, ordinary retirements of utility plant and salvage value are netted and charged to accumulated depreciation upon removal from utility plant accounts and no gain or loss is recognized consistent with rate-making principles. However, if regulators have approved recovery of the remaining net book value of property, plant and equipment that is retired early, or such approval by regulators is probable, the remaining net book value is reclassified from property, plant and equipment to regulatory assets upon retirement.

Non-utility and Other Property -

General - Non-utility property is recorded at the original cost of acquisition or construction, which includes material, labor and contractor services. Repairs, replacements and renewals of items of property determined to be less than a unit of property or that do not increase the property’s life or functionality are charged to maintenance expense. Upon retirement or sale of non-utility property, the original cost and related accumulated depreciation are removed from the accounts and any gain or loss is included in the income statements.

Costs related to software developed or obtained for internal use are capitalized and amortized on a straight-line basis over the estimated useful life of the related software. If software is retired prior to being fully amortized, the remaining book value is recorded as a loss in the income statements.

Depreciation

IPL and WPL use a combination of remaining life and straight-line depreciation methods as approved by their respective regulatory commissions. The composite or group method of depreciation is used, in which a single depreciation rate is applied to the gross investment in a particular class of property. This method pools similar assets and then depreciates each group as a whole. Periodic depreciation studies are performed to determine the appropriate group lives, net salvage, estimated cost of removal and group depreciation rates. These depreciation studies are subject to review and approval by IPL’s and WPL’s respective regulatory commissions. Depreciation expense is included within the recoverable cost of service component of rates collected from customers. The average rates of depreciation for electric, gas and other properties, consistent with current rate-making practices, were as follows:

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Electric - generation	3.4%	3.5%	3.8%	3.5%	3.5%	3.6%
Electric - distribution	2.9%	2.8%	2.9%	2.6%	2.6%	2.6%
Electric - other	5.7%	5.2%	5.3%	7.4%	6.1%	5.8%
Gas	3.3%	3.3%	3.3%	2.4%	2.4%	2.5%
Other	6.1%	6.3%	5.9%	5.4%	5.9%	5.6%

AFUDC

AFUDC represents costs to finance construction additions, including a return on equity component and cost of debt component as required by regulatory accounting. AFUDC for IPL’s construction projects is calculated in accordance with FERC guidelines. AFUDC for WPL’s retail and wholesale jurisdiction construction projects is calculated in accordance with PSCW and FERC guidelines, respectively. The AFUDC rates, computed in accordance with the prescribed regulatory formula, were as follows:

	2021	2020	2019
IPL (Wind generation CWIP)	7.0%	7.1%	7.4%
IPL (other CWIP)	7.2%	7.2%	7.5%
WPL (retail jurisdiction)	7.0%	7.0%	6.8%
WPL (wholesale jurisdiction)	5.6%	6.3%	6.9%

In accordance with their respective regulatory commission decisions, IPL applies its AFUDC rates to 100% of applicable CWIP balances and WPL generally applies its AFUDC rates to 50% of applicable CWIP balances. WPL may apply its AFUDC rates to 100% of the retail portion of the CWIP balances for construction projects requiring a CA or CPCN that were approved by the PSCW after its then most recent rate order, including West Riverside and the first and second solar generation CAs.

Revenue Recognition

Utility - Revenues from Alliant Energy’s utility business are primarily from electric and gas sales to customers. Utility revenues are recognized over time as services are rendered or commodities are delivered to customers, and include billed and unbilled components. The billed component is based on the reading of customers’ meters, which occurs on a systematic basis throughout each reporting period and represents the fair value of the services provided or commodities delivered. The unbilled component is estimated and recorded at the end of each reporting period based on estimated amounts of energy delivered to customers since the end of each customer’s last billing period. The unbilled component is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates.

IPL and WPL accrue revenues from their wholesale customers to the extent that the actual net revenue requirements calculated in accordance with FERC-approved formula rates for the reporting period are higher or lower than the amounts billed to wholesale customers during such period. Regulatory assets or regulatory liabilities are recorded as the offset for these accrued revenues under formulaic rate-making programs. As of December 31, 2021, the related amounts accrued for IPL and WPL were not material.

IPL and WPL participate in bid/offer-based wholesale energy and ancillary services markets operated by MISO. The MISO transactions are grouped together, resulting in a net supply to or net purchase from MISO for each hour of each day. The net supply to MISO is recorded as bulk power sales in “Electric utility revenues” and the net purchase from MISO is recorded in “Electric production fuel and purchased power” in the income statements.

Non-utility - Revenues from Alliant Energy’s non-utility businesses are primarily from its Travero business and are recognized over time as services are rendered to customers.

Taxes Collected from Customers - Sales or various other taxes collected by certain of Alliant Energy’s subsidiaries on behalf of other agencies are recorded on a net basis and are not included in revenues.

Other - Alliant Energy, IPL and WPL do not disclose the value of unsatisfied performance obligations for: (i) contracts with an original expected length of one year or less; and (ii) contracts for which revenue is recognized at the amount to which they have the right to invoice for services performed.

Utility Cost Recovery Mechanisms

Electric Production Fuel and Purchased Power (Fuel-related Costs) - Fuel-related costs are incurred to generate and purchase electricity to meet the demand of IPL’s and WPL’s electric customers. These fuel-related costs include the cost of fossil fuels (primarily natural gas and coal) used to produce electricity at their EGUs, and electricity purchased from MISO wholesale energy markets and under PPAs. These fuel-related costs are recorded in “Electric production fuel and purchased power” in the income statements.

IPL Retail - The cost recovery mechanisms for IPL’s retail electric customers provide for monthly adjustments to their electric rates for changes in fuel-related costs. Changes in the under-/over-collection of these costs are recognized in “Electric production fuel and purchased power” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

WPL Retail - The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. If WPL’s actual fuel-related costs fall outside these fuel monitoring ranges, WPL is authorized to defer the incremental under-/over-collection of fuel-related costs that are outside the approved ranges. Deferral of under-collections are reduced to the extent actual return on common equity earned by WPL during the fuel cost plan year exceeds the most recently authorized return on common equity. Deferred amounts for fuel-related costs outside the approved fuel monitoring ranges are recognized in “Electric production fuel and purchased power” in Alliant Energy’s and WPL’s income statements. The cumulative effects of these deferred amounts are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and WPL’s balance sheets until they are reflected in future billings to customers.

IPL and WPL Wholesale - The cost recovery mechanisms for IPL’s and WPL’s wholesale electric customers provide for subsequent adjustments to their electric rates for changes in fuel-related costs. Changes in the under-/over-collection of these costs are recognized in “Electric production fuel and purchased power” in the income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Purchased Electric Capacity - PPAs help meet the electricity demand of IPL’s and WPL’s customers. Certain PPAs include minimum payments for IPL’s and WPL’s rights to electric generating capacity, which are charged each period to “Electric production fuel and purchased power” in the income statements. Purchased electric capacity expenses are recovered from IPL’s and WPL’s retail electric customers through changes in base rates determined during periodic rate proceedings. Purchased electric capacity expenses are recovered from IPL’s and WPL’s wholesale electric customers through annual changes in base rates determined by a formula rate structure.

Electric Transmission Service - Costs incurred for the transmission of electricity to meet the demands of IPL’s and WPL’s customers are charged to “Electric transmission service” in the income statements.

IPL Retail - Electric transmission service expense is recovered from IPL’s retail electric customers through a transmission cost rider. This cost recovery mechanism provides for periodic adjustments to electric rates charged to retail electric customers for changes in electric transmission service expense. Changes in the under-/over-collection of these costs are recognized in “Electric transmission service” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

WPL Retail - Electric transmission service expense is recovered from WPL’s retail electric customers through changes in base rates determined during periodic rate proceedings. Pursuant to escrow accounting treatment approved by the PSCW, the difference between actual electric transmission service expense incurred and the amount of electric transmission service costs collected from customers as electric revenues is recognized in “Electric transmission service” in Alliant Energy’s and WPL’s income statements. An offsetting amount is recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and WPL’s balance sheets until reflected in future billings to customers.

IPL and WPL Wholesale - IPL and WPL arrange transmission service for the majority of their respective wholesale electric customers. Electric transmission service expense is allocated to and recovered from these customers based on a load ratio share computation.

Cost of Gas Sold - Costs are incurred for the purchase, transportation and storage of natural gas to serve IPL’s and WPL’s gas customers and the costs associated with the natural gas delivered to customers are charged to “Cost of gas sold” in the income statements. The tariffs for IPL’s and WPL’s retail gas customers provide for subsequent adjustments to their rates periodically for changes in the cost of gas sold. Changes in the under-/over-collection of these costs are also recognized in “Cost of gas sold” in the income statements. The cumulative effects of the under-/over-collection of these costs are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Energy Efficiency Costs - Costs incurred to fund energy efficiency programs and initiatives that help customers reduce their energy usage are charged to “Other operation and maintenance” in the income statements. Energy efficiency costs incurred by IPL are recovered from its retail electric and gas customers through energy efficiency and demand response cost recovery factor tariffs, which are revised annually and include a reconciliation to eliminate any under-/over-collection of energy efficiency costs from prior periods. Energy efficiency costs incurred by WPL are recovered from retail electric and gas customers through changes in base rates determined during periodic rate proceedings. Reconciliations of any under-/over-collection of energy efficiency costs from prior periods are also addressed in WPL’s periodic rate proceedings. Changes in the under-/over-collection of energy efficiency costs for IPL and WPL are recognized in “Other operation and maintenance” in the income statements. The cumulative effects of the under-/over-collection of these costs for IPL and WPL are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers.

Renewable Energy Rider - Effective with the implementation of final rates covering the 2020 forward-looking Test Period, IPL recovers a return of, as well as earn a return on, its new wind generation placed in service in 2019 and 2020 from its retail electric customers through a renewable energy rider. Other applicable costs and tax benefits associated with the new wind generation, excluding operation and maintenance expenses, are also included in the rider. This cost recovery mechanism provides for annual adjustments to electric rates charged to IPL’s retail electric customers for actual renewable energy costs and tax benefits. Changes in the under-/over-collection of these costs are recognized in “Electric utility revenue” in Alliant Energy’s and IPL’s income statements. The cumulative effects of the under-/over-collection of these costs for IPL are recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and IPL’s balance sheets until they are reflected in future billings to customers.

Financial Instruments

Financial instruments are periodically used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. The fair value of those financial instruments that are determined to be derivatives are recorded as assets or liabilities on the balance sheets. Certain commodity purchase and sales contracts qualified for and were designated under the normal purchase and sale exception, and were accounted for on the accrual basis of accounting. Alliant Energy, IPL and WPL have elected to not net the fair value amounts of derivatives subject to a master netting arrangement by counterparty. Alliant Energy, IPL and WPL do not offset fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) against fair value amounts recognized for derivative instruments that are executed with the same counterparty under the same master netting arrangement.

Asset Impairments

Property, Plant and Equipment of Regulated Operations - Property, plant and equipment of regulated operations are reviewed for possible impairment whenever events or changes in circumstances indicate all or a portion of the carrying value of the assets may be disallowed for rate-making purposes. If IPL or WPL are disallowed recovery of any portion of, or are only allowed a partial return on, the carrying value of their regulated property, plant and equipment that is under construction, has been recently completed or is probable of abandonment, or conclude it is probable recovery or a full return will be disallowed, then an impairment charge is recognized.

Property, Plant and Equipment of Non-utility Operations - Property, plant and equipment of non-utility operations are reviewed for possible impairment whenever events or changes in circumstances indicate the carrying value of the assets may not be recoverable. Impairment is indicated if the carrying value of an asset exceeds its undiscounted future cash flows. If an impairment is indicated, a charge is recognized equal to the amount the carrying value exceeds the asset’s fair value.

Unconsolidated Equity Investments - If events or circumstances indicate the carrying value of investments accounted for under the equity method of accounting exceeds fair value and the decline in value is other than temporary, potential impairment is assessed. If an impairment is indicated, a charge is recognized equal to the amount the carrying value exceeds the investment’s fair value.

Asset Retirement Obligations

The fair value of a legal obligation associated with the retirement of an asset is recorded as a liability when an asset is placed in service, when a legal obligation is subsequently identified or when sufficient information becomes available to determine a reasonable estimate of the fair value of future retirement costs. When an ARO is recorded as a liability, an equivalent amount is added to the asset cost. The fair value of AROs at inception is determined using discounted cash flows analyses. The liability is accreted to its present value and the capitalized cost is depreciated over the useful life of the related asset. Accretion and depreciation expenses related to AROs for IPL’s and WPL’s regulated operations are recorded to regulatory assets on the balance sheets. Revisions in estimated cash flows for IPL’s and WPL’s regulated operations are recorded as an increase or decrease to the ARO liability, with an offset to the asset cost, unless the asset is already retired and then the offset is recorded to regulatory assets or regulatory liabilities on the balance sheets. Upon regulatory approval to recover IPL’s AROs expenditures, its regulatory assets are amortized to depreciation and amortization expenses in Alliant Energy’s and IPL’s income statements over the same time period the ARO expenditures are recovered from IPL’s customers. WPL’s regulatory assets related to AROs are recovered as a component of depreciation rates pursuant to PSCW and FERC orders. Upon settlement of the ARO liability, an entity settles the obligation for its recorded amount or incurs a gain or loss. Any gains or losses related to AROs for IPL’s and WPL’s regulated operations are recorded to regulatory liabilities or regulatory assets on the balance sheets.

Debt Issuance and Retirement Costs

Debt issuance costs and debt premiums or discounts are presented on the balance sheets as a direct adjustment to the carrying amount of the related debt liability, and are deferred and amortized over the expected life of each debt issue, considering maturity dates and, if applicable, redemption rights held by others. Alliant Energy’s non-utility businesses and Corporate Services record to interest expense in the period of retirement any unamortized debt issuance costs and debt premiums or discounts on debt retired early.

Current Expected Credit Losses Estimates

Current expected credit losses are estimated for trade and other receivables and credit exposures on guarantees of the performance by third parties. The current expected credit losses for short-term trade receivables are based on estimates of losses resulting from the inability of customers to make required payments. The methodology used to estimate losses is based on historical write-offs, regional economic conditions, significant events that could impact collectability, such as impacts related to COVID-19, significant weather related matters including the derecho windstorm and related regulatory actions, and forecasted changes to the accounts receivable aging portfolio and write-offs. The current expected credit losses related to guarantees of the performance by third parties are estimated using both quantitative and qualitative information, which utilizes potential outcomes in a range of possible estimated amounts.In 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 17(d) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s equity statement for 2020.

Variable Interest Entities

An entity is considered a VIE if its equity investors do not have sufficient equity at risk for the entity to finance its activities without additional subordinated financial support from other parties, the entity is structured with disproportionate voting rights and substantially all of the entity’s activities are conducted on behalf of the investor with disproportionately fewer voting rights, or its equity investors lack any of the following characteristics: (1) power, through voting rights or similar rights, to direct the activities of the entity that most significantly impact the entity’s economic performance; (2) the obligation to absorb expected losses of the entity; or (3) the right to receive expected benefits of the entity. The primary beneficiary of a VIE is required to consolidate the VIE. The financial statements do not reflect any consolidation of VIEs.

Leases

The determination of whether an arrangement qualifies as a lease occurs at the inception of the arrangement. Arrangements that qualify as leases are classified as either operating or finance. Operating and finance lease liabilities represent obligations to make payments arising from the lease. Operating and finance lease assets represent the right to use an underlying asset for the lease term and are recognized at the lease commencement date based on the present value of the lease payments over the lease term. Leases with initial terms less than 12 months are not recognized as leases. For operating leases, an incremental borrowing rate, as determined at the lease commencement date, is used to determine the present value of the lease payments. For finance leases, the rate implicit in the lease, if known, is used to determine the present value of the lease payments. If the rate implicit in the lease is not known, the incremental borrowing rate is used to determine the present value of the lease payments. Lease terms include options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Operating lease expense is recognized on a straight-line basis over the expected lease term. Finance lease expense is comprised of depreciation and amortization, and interest expenses. Finance lease assets related to leased land for solar generation are amortized on a straight-line basis over the lease term, and are accounted for as operating leases for rate-making purposes. All other finance lease assets are depreciated on a straight-line basis over the shorter of the useful life of the underlying asset or the lease term.

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Summary Of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2021

Schedule of Average Rates of Depreciation

The average rates of depreciation for electric, gas and other properties, consistent with current rate-making practices, were as follows:

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Electric - generation	3.4%	3.5%	3.8%	3.5%	3.5%	3.6%
Electric - distribution	2.9%	2.8%	2.9%	2.6%	2.6%	2.6%
Electric - other	5.7%	5.2%	5.3%	7.4%	6.1%	5.8%
Gas	3.3%	3.3%	3.3%	2.4%	2.4%	2.5%
Other	6.1%	6.3%	5.9%	5.4%	5.9%	5.6%

Schedule of Allowance for Funds Used During Construction Rates

The AFUDC rates, computed in accordance with the prescribed regulatory formula, were as follows:

	2021	2020	2019
IPL (Wind generation CWIP)	7.0%	7.1%	7.4%
IPL (other CWIP)	7.2%	7.2%	7.5%
WPL (retail jurisdiction)	7.0%	7.0%	6.8%
WPL (wholesale jurisdiction)	5.6%	6.3%	6.9%

IPL [Member]

Schedule of Average Rates of Depreciation

The average rates of depreciation for electric, gas and other properties, consistent with current rate-making practices, were as follows:

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Electric - generation	3.4%	3.5%	3.8%	3.5%	3.5%	3.6%
Electric - distribution	2.9%	2.8%	2.9%	2.6%	2.6%	2.6%
Electric - other	5.7%	5.2%	5.3%	7.4%	6.1%	5.8%
Gas	3.3%	3.3%	3.3%	2.4%	2.4%	2.5%
Other	6.1%	6.3%	5.9%	5.4%	5.9%	5.6%

Schedule of Allowance for Funds Used During Construction Rates

The AFUDC rates, computed in accordance with the prescribed regulatory formula, were as follows:

	2021	2020	2019
IPL (Wind generation CWIP)	7.0%	7.1%	7.4%
IPL (other CWIP)	7.2%	7.2%	7.5%
WPL (retail jurisdiction)	7.0%	7.0%	6.8%
WPL (wholesale jurisdiction)	5.6%	6.3%	6.9%

WPL [Member]

Schedule of Average Rates of Depreciation

The average rates of depreciation for electric, gas and other properties, consistent with current rate-making practices, were as follows:

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Electric - generation	3.4%	3.5%	3.8%	3.5%	3.5%	3.6%
Electric - distribution	2.9%	2.8%	2.9%	2.6%	2.6%	2.6%
Electric - other	5.7%	5.2%	5.3%	7.4%	6.1%	5.8%
Gas	3.3%	3.3%	3.3%	2.4%	2.4%	2.5%
Other	6.1%	6.3%	5.9%	5.4%	5.9%	5.6%

Schedule of Allowance for Funds Used During Construction Rates

The AFUDC rates, computed in accordance with the prescribed regulatory formula, were as follows:

	2021	2020	2019
IPL (Wind generation CWIP)	7.0%	7.1%	7.4%
IPL (other CWIP)	7.2%	7.2%	7.5%
WPL (retail jurisdiction)	7.0%	7.0%	6.8%
WPL (wholesale jurisdiction)	5.6%	6.3%	6.9%

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Regulatory Matters (Tables)

12 Months Ended

Dec. 31, 2021

Regulatory Assets [Line Items]

Schedule of Regulatory Assets

At December 31, regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Tax-related	$934	$890	$884	$843	$50	$47
Pension and OPEB costs	462	580	228	291	234	289
AROs	128	119	89	81	39	38
Assets retired early	92	113	66	77	26	36
IPL’s DAEC PPA amendment	90	110	90	110	—	—
WPL’s Western Wisconsin gas distribution expansion investments	52	55	—	—	52	55
Commodity cost recovery	42	4	2	1	40	3
Derivatives	8	26	4	13	4	13
Other	132	113	80	67	52	46
	$1,940	$2,010	$1,443	$1,483	$497	$527

Schedule of Assets Retired Early

Details regarding the recovery of the remaining net book value of these assets from IPL’s and WPL’s customers are as follows (dollars in millions):

Entity	Asset	Retirement Date	Regulatory Asset Balance as of Dec. 31, 2021	Recovery	Regulatory Approval
IPL	Sutherland Units 1 and 3	2017	$19	Return of and return on remaining net book value through 2027	IUB and FERC
IPL	M.L. Kapp Unit 2	2018	18	Return of and return on remaining net book value through 2029	IUB and FERC
IPL	Analog electric meters	2019	29	Return of remaining net book value through 2028	IUB and FERC
WPL	Nelson Dewey Units 1 and 2 and Edgewater Unit 3	2015	6	Return of and return on remaining net book value through 2022	PSCW and FERC
WPL	Edgewater Unit 4	2018	20	Return of and return on remaining net book value through 2028	PSCW and FERC

Schedule of Regulatory Liabilities

At December 31, regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Tax-related	$585	$732	$312	$331	$273	$401
Cost of removal obligations	384	367	252	238	132	129
Derivatives	166	28	77	25	89	3
Electric transmission cost recovery	51	68	27	39	24	29
WPL’s West Riverside liquidated damages	36	38	—	—	36	38
Other	49	73	23	43	26	30
	$1,271	$1,306	$691	$676	$580	$630

IPL [Member]

Regulatory Assets [Line Items]

Schedule of Regulatory Assets

At December 31, regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Tax-related	$934	$890	$884	$843	$50	$47
Pension and OPEB costs	462	580	228	291	234	289
AROs	128	119	89	81	39	38
Assets retired early	92	113	66	77	26	36
IPL’s DAEC PPA amendment	90	110	90	110	—	—
WPL’s Western Wisconsin gas distribution expansion investments	52	55	—	—	52	55
Commodity cost recovery	42	4	2	1	40	3
Derivatives	8	26	4	13	4	13
Other	132	113	80	67	52	46
	$1,940	$2,010	$1,443	$1,483	$497	$527

Schedule of Assets Retired Early

Details regarding the recovery of the remaining net book value of these assets from IPL’s and WPL’s customers are as follows (dollars in millions):

Entity	Asset	Retirement Date	Regulatory Asset Balance as of Dec. 31, 2021	Recovery	Regulatory Approval
IPL	Sutherland Units 1 and 3	2017	$19	Return of and return on remaining net book value through 2027	IUB and FERC
IPL	M.L. Kapp Unit 2	2018	18	Return of and return on remaining net book value through 2029	IUB and FERC
IPL	Analog electric meters	2019	29	Return of remaining net book value through 2028	IUB and FERC
WPL	Nelson Dewey Units 1 and 2 and Edgewater Unit 3	2015	6	Return of and return on remaining net book value through 2022	PSCW and FERC
WPL	Edgewater Unit 4	2018	20	Return of and return on remaining net book value through 2028	PSCW and FERC

Schedule of Regulatory Liabilities

At December 31, regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Tax-related	$585	$732	$312	$331	$273	$401
Cost of removal obligations	384	367	252	238	132	129
Derivatives	166	28	77	25	89	3
Electric transmission cost recovery	51	68	27	39	24	29
WPL’s West Riverside liquidated damages	36	38	—	—	36	38
Other	49	73	23	43	26	30
	$1,271	$1,306	$691	$676	$580	$630

WPL [Member]

Regulatory Assets [Line Items]

Schedule of Regulatory Assets

At December 31, regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Tax-related	$934	$890	$884	$843	$50	$47
Pension and OPEB costs	462	580	228	291	234	289
AROs	128	119	89	81	39	38
Assets retired early	92	113	66	77	26	36
IPL’s DAEC PPA amendment	90	110	90	110	—	—
WPL’s Western Wisconsin gas distribution expansion investments	52	55	—	—	52	55
Commodity cost recovery	42	4	2	1	40	3
Derivatives	8	26	4	13	4	13
Other	132	113	80	67	52	46
	$1,940	$2,010	$1,443	$1,483	$497	$527

Schedule of Assets Retired Early

Details regarding the recovery of the remaining net book value of these assets from IPL’s and WPL’s customers are as follows (dollars in millions):

Entity	Asset	Retirement Date	Regulatory Asset Balance as of Dec. 31, 2021	Recovery	Regulatory Approval
IPL	Sutherland Units 1 and 3	2017	$19	Return of and return on remaining net book value through 2027	IUB and FERC
IPL	M.L. Kapp Unit 2	2018	18	Return of and return on remaining net book value through 2029	IUB and FERC
IPL	Analog electric meters	2019	29	Return of remaining net book value through 2028	IUB and FERC
WPL	Nelson Dewey Units 1 and 2 and Edgewater Unit 3	2015	6	Return of and return on remaining net book value through 2022	PSCW and FERC
WPL	Edgewater Unit 4	2018	20	Return of and return on remaining net book value through 2028	PSCW and FERC

Schedule of Regulatory Liabilities

At December 31, regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Tax-related	$585	$732	$312	$331	$273	$401
Cost of removal obligations	384	367	252	238	132	129
Derivatives	166	28	77	25	89	3
Electric transmission cost recovery	51	68	27	39	24	29
WPL’s West Riverside liquidated damages	36	38	—	—	36	38
Other	49	73	23	43	26	30
	$1,271	$1,306	$691	$676	$580	$630

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Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2021

Property, Plant and Equipment [Line Items]

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
	2021	2020	2021	2020	2021	2020
Utility:
Electric plant:
Generation in service	$7,539	$8,222	$4,922	$4,884	$2,617	$3,338
Distribution in service	6,537	6,216	3,652	3,470	2,885	2,746
Other in service	540	536	363	358	177	178
Anticipated to be retired early (a)	2,094	1,269	487	459	1,607	810
Total electric plant	16,710	16,243	9,424	9,171	7,286	7,072
Gas plant in service	1,636	1,563	878	844	758	719
Other plant in service	621	534	398	354	223	180
Accumulated depreciation	(5,263)	(4,868)	(2,897)	(2,671)	(2,366)	(2,197)
Net plant	13,704	13,472	7,803	7,698	5,901	5,774
Leased Sheboygan Falls Energy Facility, net (b)	—	—	—	—	21	27
Leased land for solar generation, net	11	—	—	—	11	—
Construction work in progress	778	405	174	185	604	220
Other, net	7	7	6	6	1	1
Total utility	14,500	13,884	7,983	7,889	6,538	6,022
Non-utility and other:
Non-utility Generation, net (c)	75	79	—	—	—	—
Corporate Services and other, net (d)	412	373	—	—	—	—
Total non-utility and other	487	452	—	—	—	—
Total property, plant and equipment	$14,987	$14,336	$7,983	$7,889	$6,538	$6,022

(a)In 2020, IPL and WPL received approval from MISO to retire Lansing and Edgewater Unit 5, respectively, and currently anticipate retiring Lansing by the end of 2022 and Edgewater Unit 5 by early 2023. In 2021, WPL received approval from MISO to retire Columbia Units 1 and 2, and currently anticipates retiring Columbia Unit 1 by the end of 2023 and Columbia Unit 2 by the end of 2024. Alliant Energy and IPL concluded that Lansing, and Alliant Energy and WPL concluded that Edgewater Unit 5 and Columbia Units 1 and 2, met the criteria to be considered probable of abandonment as of December 31, 2021. IPL and WPL are currently allowed a full recovery of and a full return on its respective EGUs from both its retail and wholesale customers, and as a result, Alliant Energy, IPL and WPL concluded that no disallowance was required as of December 31, 2021. As of December 31, 2021, net book values were $245 million for Lansing, $527 million for Edgewater Unit 5, and $460 million for Columbia Units 1 and 2 in aggregate.

(b)Less accumulated amortization of $100 million and $95 million for WPL as of December 31, 2021 and 2020, respectively. For Alliant Energy, the leased Sheboygan Falls Energy Facility is eliminated 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 $67 million and $63 million for Alliant Energy as of December 31, 2021 and 2020, respectively.

(d)Less accumulated depreciation of $245 million and $210 million for Alliant Energy as of December 31, 2021 and 2020, respectively.

Allowance For Funds Used During Construction

The amount of AFUDC generated by equity and debt components was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Equity	$18	$39	$66	$7	$17	$35	$11	$22	$31
Debt	7	16	27	2	7	15	5	9	12
	$25	$55	$93	$9	$24	$50	$16	$31	$43

IPL [Member]

Property, Plant and Equipment [Line Items]

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
	2021	2020	2021	2020	2021	2020
Utility:
Electric plant:
Generation in service	$7,539	$8,222	$4,922	$4,884	$2,617	$3,338
Distribution in service	6,537	6,216	3,652	3,470	2,885	2,746
Other in service	540	536	363	358	177	178
Anticipated to be retired early (a)	2,094	1,269	487	459	1,607	810
Total electric plant	16,710	16,243	9,424	9,171	7,286	7,072
Gas plant in service	1,636	1,563	878	844	758	719
Other plant in service	621	534	398	354	223	180
Accumulated depreciation	(5,263)	(4,868)	(2,897)	(2,671)	(2,366)	(2,197)
Net plant	13,704	13,472	7,803	7,698	5,901	5,774
Leased Sheboygan Falls Energy Facility, net (b)	—	—	—	—	21	27
Leased land for solar generation, net	11	—	—	—	11	—
Construction work in progress	778	405	174	185	604	220
Other, net	7	7	6	6	1	1
Total utility	14,500	13,884	7,983	7,889	6,538	6,022
Non-utility and other:
Non-utility Generation, net (c)	75	79	—	—	—	—
Corporate Services and other, net (d)	412	373	—	—	—	—
Total non-utility and other	487	452	—	—	—	—
Total property, plant and equipment	$14,987	$14,336	$7,983	$7,889	$6,538	$6,022

(a)In 2020, IPL and WPL received approval from MISO to retire Lansing and Edgewater Unit 5, respectively, and currently anticipate retiring Lansing by the end of 2022 and Edgewater Unit 5 by early 2023. In 2021, WPL received approval from MISO to retire Columbia Units 1 and 2, and currently anticipates retiring Columbia Unit 1 by the end of 2023 and Columbia Unit 2 by the end of 2024. Alliant Energy and IPL concluded that Lansing, and Alliant Energy and WPL concluded that Edgewater Unit 5 and Columbia Units 1 and 2, met the criteria to be considered probable of abandonment as of December 31, 2021. IPL and WPL are currently allowed a full recovery of and a full return on its respective EGUs from both its retail and wholesale customers, and as a result, Alliant Energy, IPL and WPL concluded that no disallowance was required as of December 31, 2021. As of December 31, 2021, net book values were $245 million for Lansing, $527 million for Edgewater Unit 5, and $460 million for Columbia Units 1 and 2 in aggregate.

(b)Less accumulated amortization of $100 million and $95 million for WPL as of December 31, 2021 and 2020, respectively. For Alliant Energy, the leased Sheboygan Falls Energy Facility is eliminated 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 $67 million and $63 million for Alliant Energy as of December 31, 2021 and 2020, respectively.

(d)Less accumulated depreciation of $245 million and $210 million for Alliant Energy as of December 31, 2021 and 2020, respectively.

Allowance For Funds Used During Construction

The amount of AFUDC generated by equity and debt components was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Equity	$18	$39	$66	$7	$17	$35	$11	$22	$31
Debt	7	16	27	2	7	15	5	9	12
	$25	$55	$93	$9	$24	$50	$16	$31	$43

WPL [Member]

Property, Plant and Equipment [Line Items]

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
	2021	2020	2021	2020	2021	2020
Utility:
Electric plant:
Generation in service	$7,539	$8,222	$4,922	$4,884	$2,617	$3,338
Distribution in service	6,537	6,216	3,652	3,470	2,885	2,746
Other in service	540	536	363	358	177	178
Anticipated to be retired early (a)	2,094	1,269	487	459	1,607	810
Total electric plant	16,710	16,243	9,424	9,171	7,286	7,072
Gas plant in service	1,636	1,563	878	844	758	719
Other plant in service	621	534	398	354	223	180
Accumulated depreciation	(5,263)	(4,868)	(2,897)	(2,671)	(2,366)	(2,197)
Net plant	13,704	13,472	7,803	7,698	5,901	5,774
Leased Sheboygan Falls Energy Facility, net (b)	—	—	—	—	21	27
Leased land for solar generation, net	11	—	—	—	11	—
Construction work in progress	778	405	174	185	604	220
Other, net	7	7	6	6	1	1
Total utility	14,500	13,884	7,983	7,889	6,538	6,022
Non-utility and other:
Non-utility Generation, net (c)	75	79	—	—	—	—
Corporate Services and other, net (d)	412	373	—	—	—	—
Total non-utility and other	487	452	—	—	—	—
Total property, plant and equipment	$14,987	$14,336	$7,983	$7,889	$6,538	$6,022

(a)In 2020, IPL and WPL received approval from MISO to retire Lansing and Edgewater Unit 5, respectively, and currently anticipate retiring Lansing by the end of 2022 and Edgewater Unit 5 by early 2023. In 2021, WPL received approval from MISO to retire Columbia Units 1 and 2, and currently anticipates retiring Columbia Unit 1 by the end of 2023 and Columbia Unit 2 by the end of 2024. Alliant Energy and IPL concluded that Lansing, and Alliant Energy and WPL concluded that Edgewater Unit 5 and Columbia Units 1 and 2, met the criteria to be considered probable of abandonment as of December 31, 2021. IPL and WPL are currently allowed a full recovery of and a full return on its respective EGUs from both its retail and wholesale customers, and as a result, Alliant Energy, IPL and WPL concluded that no disallowance was required as of December 31, 2021. As of December 31, 2021, net book values were $245 million for Lansing, $527 million for Edgewater Unit 5, and $460 million for Columbia Units 1 and 2 in aggregate.

(b)Less accumulated amortization of $100 million and $95 million for WPL as of December 31, 2021 and 2020, respectively. For Alliant Energy, the leased Sheboygan Falls Energy Facility is eliminated 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 $67 million and $63 million for Alliant Energy as of December 31, 2021 and 2020, respectively.

(d)Less accumulated depreciation of $245 million and $210 million for Alliant Energy as of December 31, 2021 and 2020, respectively.

Allowance For Funds Used During Construction

The amount of AFUDC generated by equity and debt components was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Equity	$18	$39	$66	$7	$17	$35	$11	$22	$31
Debt	7	16	27	2	7	15	5	9	12
	$25	$55	$93	$9	$24	$50	$16	$31	$43

XML

Jointly-Owned Electric Utility Plant (Tables)

12 Months Ended

Dec. 31, 2021

Jointly Owned Electric Utility Plant [Line Items]

Components of Jointly-Owned Electric Utility Plants

Information relative to IPL’s and WPL’s ownership interest in these jointly-owned EGUs at December 31, 2021 was as follows (dollars in millions):

	Ownership	Electric	Accumulated Provision	Construction
	Interest %	Plant	for Depreciation	Work in Progress
IPL
Ottumwa Unit 1	48.0%	$599	$214	$11
George Neal Unit 4	25.7%	193	100	2
George Neal Unit 3	28.0%	173	74	3
Louisa Unit 1	4.0%	40	23	—
		1,005	411	16
WPL
Columbia Units 1-2	53.5%	802	314	6
West Riverside Energy Center and Solar Garden	91.0%	706	33	3
Forward Wind Energy Center	42.6%	118	48	—
		1,626	395	9
Alliant Energy		$2,631	$806	$25

IPL [Member]

Jointly Owned Electric Utility Plant [Line Items]

Components of Jointly-Owned Electric Utility Plants

Information relative to IPL’s and WPL’s ownership interest in these jointly-owned EGUs at December 31, 2021 was as follows (dollars in millions):

	Ownership	Electric	Accumulated Provision	Construction
	Interest %	Plant	for Depreciation	Work in Progress
IPL
Ottumwa Unit 1	48.0%	$599	$214	$11
George Neal Unit 4	25.7%	193	100	2
George Neal Unit 3	28.0%	173	74	3
Louisa Unit 1	4.0%	40	23	—
		1,005	411	16
WPL
Columbia Units 1-2	53.5%	802	314	6
West Riverside Energy Center and Solar Garden	91.0%	706	33	3
Forward Wind Energy Center	42.6%	118	48	—
		1,626	395	9
Alliant Energy		$2,631	$806	$25

WPL [Member]

Jointly Owned Electric Utility Plant [Line Items]

Components of Jointly-Owned Electric Utility Plants

Information relative to IPL’s and WPL’s ownership interest in these jointly-owned EGUs at December 31, 2021 was as follows (dollars in millions):

	Ownership	Electric	Accumulated Provision	Construction
	Interest %	Plant	for Depreciation	Work in Progress
IPL
Ottumwa Unit 1	48.0%	$599	$214	$11
George Neal Unit 4	25.7%	193	100	2
George Neal Unit 3	28.0%	173	74	3
Louisa Unit 1	4.0%	40	23	—
		1,005	411	16
WPL
Columbia Units 1-2	53.5%	802	314	6
West Riverside Energy Center and Solar Garden	91.0%	706	33	3
Forward Wind Energy Center	42.6%	118	48	—
		1,626	395	9
Alliant Energy		$2,631	$806	$25

XML

Receivables (Tables)

12 Months Ended

Dec. 31, 2021

Accounts Receivable [Line Items]

Accounts Receivable Details

Details for accounts receivable included on the balance sheets as of December 31 were as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Customer	$93	$101	$—	$—	$82	$92
Unbilled utility revenues	91	82	—	—	91	82
Deferred proceeds	214	188	214	188	—	—
Other	53	59	28	23	25	35
Allowance for expected credit losses	(11)	(18)	(1)	(1)	(10)	(17)
	$440	$412	$241	$210	$188	$192

Maximum And Average Outstanding Cash Proceeds

IPL’s maximum and average outstanding aggregate cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program were as follows (in millions):

	Maximum			Average
	2021	2020	2019	2021	2020	2019
Outstanding aggregate cash proceeds	$110	$96	$108	$46	$9	$36

Receivables Sold Under the Agreement

As of December 31, the attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

	2021	2020
Customer accounts receivable	$125	$114
Unbilled utility revenues	104	92
Receivables sold to third party	229	206
Less: cash proceeds	1	1
Deferred proceeds	228	205
Less: allowance for expected credit losses	14	17
Fair value of deferred proceeds	$214	$188
Outstanding receivables past due	$22	$27

Additional Attributes Of Receivables Sold Under The Agreement

Additional attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

	2021	2020	2019
Collections	$2,134	$2,025	$2,193
Write-offs, net of recoveries	9	7	19

IPL [Member]

Accounts Receivable [Line Items]

Accounts Receivable Details

Details for accounts receivable included on the balance sheets as of December 31 were as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Customer	$93	$101	$—	$—	$82	$92
Unbilled utility revenues	91	82	—	—	91	82
Deferred proceeds	214	188	214	188	—	—
Other	53	59	28	23	25	35
Allowance for expected credit losses	(11)	(18)	(1)	(1)	(10)	(17)
	$440	$412	$241	$210	$188	$192

Maximum And Average Outstanding Cash Proceeds

IPL’s maximum and average outstanding aggregate cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program were as follows (in millions):

	Maximum			Average
	2021	2020	2019	2021	2020	2019
Outstanding aggregate cash proceeds	$110	$96	$108	$46	$9	$36

Receivables Sold Under the Agreement

As of December 31, the attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

	2021	2020
Customer accounts receivable	$125	$114
Unbilled utility revenues	104	92
Receivables sold to third party	229	206
Less: cash proceeds	1	1
Deferred proceeds	228	205
Less: allowance for expected credit losses	14	17
Fair value of deferred proceeds	$214	$188
Outstanding receivables past due	$22	$27

Additional Attributes Of Receivables Sold Under The Agreement

Additional attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

	2021	2020	2019
Collections	$2,134	$2,025	$2,193
Write-offs, net of recoveries	9	7	19

WPL [Member]

Accounts Receivable [Line Items]

Accounts Receivable Details

Details for accounts receivable included on the balance sheets as of December 31 were as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Customer	$93	$101	$—	$—	$82	$92
Unbilled utility revenues	91	82	—	—	91	82
Deferred proceeds	214	188	214	188	—	—
Other	53	59	28	23	25	35
Allowance for expected credit losses	(11)	(18)	(1)	(1)	(10)	(17)
	$440	$412	$241	$210	$188	$192

XML

Investments (Tables)

12 Months Ended

Dec. 31, 2021

Schedule of Equity Method Investments [Line Items]

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, 2021	2021	2020	2021	2020	2019
ATC Holdings	16%, 20%	$338	$331	($43)	($47)	($45)
Non-utility wind farm in Oklahoma	50%	99	103	(4)	(8)	(5)
Corporate venture investments	Various	52	31	(13)	(4)	(1)
Other	Various	19	11	(2)	(2)	(2)
		$508	$476	($62)	($61)	($53)

Summary Financial Information

Summary aggregate financial information from the financial statements of these holdings is as follows (in millions):

	Alliant Energy
	2021	2020	2019
Revenues	$802	$801	$783
Operating income	357	376	359
Net income	358	343	340
As of December 31:
Current assets	112	121
Non-current assets	7,036	6,388
Current liabilities	455	317
Non-current liabilities	3,110	2,997
Noncontrolling interest	247	192

XML

Common Equity (Tables)

12 Months Ended

Dec. 31, 2021

Schedule of Common Equity [Line Items]

Common Stock Activity

A summary of Alliant Energy’s common stock activity was as follows:

	2021	2020	2019
Shares outstanding, January 1	249,868,415	245,022,800	236,063,279
Equity forward agreements	—	4,275,127	8,358,973
Shareowner Direct Plan	492,565	472,283	501,808
Equity-based compensation plans	113,549	98,205	101,478
Other	—	—	(2,738)
Shares outstanding, December 31	250,474,529	249,868,415	245,022,800

XML

Preferred Stock (Tables)

12 Months Ended

Dec. 31, 2021

Class of Stock [Line Items]

Schedule of Carrying Value of Cumulative Preferred Stock

Information related to IPL’s cumulative preferred stock at December 31, 2020 was as follows (dollars in millions):

Series	Liquidation Preference/Stated Value	Shares Authorized	Shares Outstanding	Carrying Value
5.1%	$25	8,000,000	8,000,000	$200

IPL [Member]

Class of Stock [Line Items]

Schedule of Carrying Value of Cumulative Preferred Stock

Information related to IPL’s cumulative preferred stock at December 31, 2020 was as follows (dollars in millions):

Series	Liquidation Preference/Stated Value	Shares Authorized	Shares Outstanding	Carrying Value
5.1%	$25	8,000,000	8,000,000	$200

XML

Debt (Tables)

12 Months Ended

Dec. 31, 2021

Debt Instrument [Line Items]

Schedule of Other Short-term Borrowings

Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, classified as short-term debt was as follows (dollars in millions):

	Alliant Energy		IPL		WPL
December 31	2021	2020	2021	2020	2021	2020
Amount outstanding	$515	$389	$—	$—	$236	$257
Weighted average interest rates	0.2%	0.2%	N/A	N/A	0.2%	0.1%
Available credit facility capacity	$485	$611	$250	$250	$64	$43

	Alliant Energy		IPL		WPL
For the year ended	2021	2020	2021	2020	2021	2020
Maximum amount outstanding (based on daily outstanding balances)	$648	$495	$19	$8	$320	$266
Average amount outstanding (based on daily outstanding balances)	$459	$292	$—	$—	$172	$117
Weighted average interest rates	0.2%	0.7%	0.2%	0.5%	0.1%	0.7%

Schedule of Long-term Debt

Long-term debt, net as of December 31 was as follows (dollars in millions):

	2021			2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Senior Debentures (a):
3.25%, due 2024	$500	$500	$—	$500	$500	$—
3.4%, due 2025	250	250	—	250	250	—
5.5%, due 2025	50	50	—	50	50	—
4.1%, due 2028	500	500	—	500	500	—
3.6%, due 2029	300	300	—	300	300	—
2.3%, due 2030	400	400	—	400	400	—
6.45%, due 2033	100	100	—	100	100	—
6.3%, due 2034	125	125	—	125	125	—
6.25%, due 2039	300	300	—	300	300	—
4.7%, due 2043	250	250	—	250	250	—
3.7%, due 2046	300	300	—	300	300	—
3.5%, due 2049	300	300	—	300	300	—
3.1%, due 2051 (b)	300	300	—	—	—	—
	3,675	3,675	—	3,375	3,375	—
Debentures (a):
2.25%, due 2022	250	—	250	250	—	250
3.05%, due 2027	300	—	300	300	—	300
3%, due 2029	350	—	350	350	—	350
1.95%, due 2031 (c)	300	—	300	—	—	—
6.25%, due 2034	100	—	100	100	—	100
6.375%, due 2037	300	—	300	300	—	300
7.6%, due 2038	250	—	250	250	—	250
4.1%, due 2044	250	—	250	250	—	250
3.65%, due 2050	350	—	350	350	—	350
	2,450	—	2,450	2,150	—	2,150
Other:
AEF term loan credit agreement through March 2022, 1% at December 31, 2021 (with Alliant Energy as guarantor)	300	—	—	300	—	—
Corporate Services 3.45% senior notes, due 2022 (a)	75	—	—	75	—	—
AEF 3.75% senior notes, due 2023 (with Alliant Energy as guarantor) (a)	400	—	—	400	—	—
AEF 1.4% senior notes, due 2026 (with Alliant Energy as guarantor) (a)	200	—	—	200	—	—
AEF 4.25% senior notes, due 2028 (with Alliant Energy as guarantor) (a)	300	—	—	300	—	—
Sheboygan Power, LLC 5.06% senior secured notes, due 2022 to 2024 (secured by the Sheboygan Falls Energy Facility and related assets) (a)	24	—	—	31	—	—
Other, 1% at December 31, 2021, due 2022 to 2025	1	—	—	2	—	—
	1,300	—	—	1,308	—	—
Subtotal	7,425	3,675	2,450	6,833	3,375	2,150
Current maturities	(633)	—	(250)	(8)	—	—
Unamortized debt issuance costs	(42)	(23)	(15)	(41)	(22)	(14)
Unamortized debt (discount) and premium, net	(15)	(9)	(6)	(15)	(8)	(6)
Long-term debt, net (d)	$6,735	$3,643	$2,179	$6,769	$3,345	$2,130

(a)Contains optional redemption provisions which, if elected by the issuer at its sole discretion, could require material redemption premium payments by the issuer. The redemption premium payments under these optional redemption provisions are variable and dependent on applicable U.S. Treasury rates at the time of redemption.

(b)In November 2021, IPL issued $300 million of 3.1% senior debentures due 2051. The net proceeds from the issuance were used by IPL to retire its cumulative preferred stock in 2021 and for general corporate purposes.

(c)In September 2021, WPL issued $300 million of 1.95% debentures due 2031. The debentures were issued as green bonds, and an amount in excess of the net proceeds was disbursed for the construction and development of WPL’s wind and solar EGUs.

(d)There were no significant sinking fund requirements related to the outstanding long-term debt.

Schedule of Maturities of Long-term Debt

At December 31, 2021, long-term debt maturities for 2022 through 2026 were as follows (in millions):

	2022	2023	2024	2025	2026
IPL	$—	$—	$500	$300	$—
WPL	250	—	—	—	—
Corporate Services	75	—	—	—	—
AEF	308	408	9	—	200
Alliant Energy	$633	$408	$509	$300	$200

IPL [Member]

Debt Instrument [Line Items]

Schedule of Other Short-term Borrowings

Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, classified as short-term debt was as follows (dollars in millions):

	Alliant Energy		IPL		WPL
December 31	2021	2020	2021	2020	2021	2020
Amount outstanding	$515	$389	$—	$—	$236	$257
Weighted average interest rates	0.2%	0.2%	N/A	N/A	0.2%	0.1%
Available credit facility capacity	$485	$611	$250	$250	$64	$43

	Alliant Energy		IPL		WPL
For the year ended	2021	2020	2021	2020	2021	2020
Maximum amount outstanding (based on daily outstanding balances)	$648	$495	$19	$8	$320	$266
Average amount outstanding (based on daily outstanding balances)	$459	$292	$—	$—	$172	$117
Weighted average interest rates	0.2%	0.7%	0.2%	0.5%	0.1%	0.7%

Schedule of Long-term Debt

Long-term debt, net as of December 31 was as follows (dollars in millions):

	2021			2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Senior Debentures (a):
3.25%, due 2024	$500	$500	$—	$500	$500	$—
3.4%, due 2025	250	250	—	250	250	—
5.5%, due 2025	50	50	—	50	50	—
4.1%, due 2028	500	500	—	500	500	—
3.6%, due 2029	300	300	—	300	300	—
2.3%, due 2030	400	400	—	400	400	—
6.45%, due 2033	100	100	—	100	100	—
6.3%, due 2034	125	125	—	125	125	—
6.25%, due 2039	300	300	—	300	300	—
4.7%, due 2043	250	250	—	250	250	—
3.7%, due 2046	300	300	—	300	300	—
3.5%, due 2049	300	300	—	300	300	—
3.1%, due 2051 (b)	300	300	—	—	—	—
	3,675	3,675	—	3,375	3,375	—
Debentures (a):
2.25%, due 2022	250	—	250	250	—	250
3.05%, due 2027	300	—	300	300	—	300
3%, due 2029	350	—	350	350	—	350
1.95%, due 2031 (c)	300	—	300	—	—	—
6.25%, due 2034	100	—	100	100	—	100
6.375%, due 2037	300	—	300	300	—	300
7.6%, due 2038	250	—	250	250	—	250
4.1%, due 2044	250	—	250	250	—	250
3.65%, due 2050	350	—	350	350	—	350
	2,450	—	2,450	2,150	—	2,150
Other:
AEF term loan credit agreement through March 2022, 1% at December 31, 2021 (with Alliant Energy as guarantor)	300	—	—	300	—	—
Corporate Services 3.45% senior notes, due 2022 (a)	75	—	—	75	—	—
AEF 3.75% senior notes, due 2023 (with Alliant Energy as guarantor) (a)	400	—	—	400	—	—
AEF 1.4% senior notes, due 2026 (with Alliant Energy as guarantor) (a)	200	—	—	200	—	—
AEF 4.25% senior notes, due 2028 (with Alliant Energy as guarantor) (a)	300	—	—	300	—	—
Sheboygan Power, LLC 5.06% senior secured notes, due 2022 to 2024 (secured by the Sheboygan Falls Energy Facility and related assets) (a)	24	—	—	31	—	—
Other, 1% at December 31, 2021, due 2022 to 2025	1	—	—	2	—	—
	1,300	—	—	1,308	—	—
Subtotal	7,425	3,675	2,450	6,833	3,375	2,150
Current maturities	(633)	—	(250)	(8)	—	—
Unamortized debt issuance costs	(42)	(23)	(15)	(41)	(22)	(14)
Unamortized debt (discount) and premium, net	(15)	(9)	(6)	(15)	(8)	(6)
Long-term debt, net (d)	$6,735	$3,643	$2,179	$6,769	$3,345	$2,130

(a)Contains optional redemption provisions which, if elected by the issuer at its sole discretion, could require material redemption premium payments by the issuer. The redemption premium payments under these optional redemption provisions are variable and dependent on applicable U.S. Treasury rates at the time of redemption.

(b)In November 2021, IPL issued $300 million of 3.1% senior debentures due 2051. The net proceeds from the issuance were used by IPL to retire its cumulative preferred stock in 2021 and for general corporate purposes.

(c)In September 2021, WPL issued $300 million of 1.95% debentures due 2031. The debentures were issued as green bonds, and an amount in excess of the net proceeds was disbursed for the construction and development of WPL’s wind and solar EGUs.

(d)There were no significant sinking fund requirements related to the outstanding long-term debt.

Schedule of Maturities of Long-term Debt

At December 31, 2021, long-term debt maturities for 2022 through 2026 were as follows (in millions):

	2022	2023	2024	2025	2026
IPL	$—	$—	$500	$300	$—
WPL	250	—	—	—	—
Corporate Services	75	—	—	—	—
AEF	308	408	9	—	200
Alliant Energy	$633	$408	$509	$300	$200

WPL [Member]

Debt Instrument [Line Items]

Schedule of Other Short-term Borrowings

Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, classified as short-term debt was as follows (dollars in millions):

	Alliant Energy		IPL		WPL
December 31	2021	2020	2021	2020	2021	2020
Amount outstanding	$515	$389	$—	$—	$236	$257
Weighted average interest rates	0.2%	0.2%	N/A	N/A	0.2%	0.1%
Available credit facility capacity	$485	$611	$250	$250	$64	$43

	Alliant Energy		IPL		WPL
For the year ended	2021	2020	2021	2020	2021	2020
Maximum amount outstanding (based on daily outstanding balances)	$648	$495	$19	$8	$320	$266
Average amount outstanding (based on daily outstanding balances)	$459	$292	$—	$—	$172	$117
Weighted average interest rates	0.2%	0.7%	0.2%	0.5%	0.1%	0.7%

Schedule of Long-term Debt

Long-term debt, net as of December 31 was as follows (dollars in millions):

	2021			2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Senior Debentures (a):
3.25%, due 2024	$500	$500	$—	$500	$500	$—
3.4%, due 2025	250	250	—	250	250	—
5.5%, due 2025	50	50	—	50	50	—
4.1%, due 2028	500	500	—	500	500	—
3.6%, due 2029	300	300	—	300	300	—
2.3%, due 2030	400	400	—	400	400	—
6.45%, due 2033	100	100	—	100	100	—
6.3%, due 2034	125	125	—	125	125	—
6.25%, due 2039	300	300	—	300	300	—
4.7%, due 2043	250	250	—	250	250	—
3.7%, due 2046	300	300	—	300	300	—
3.5%, due 2049	300	300	—	300	300	—
3.1%, due 2051 (b)	300	300	—	—	—	—
	3,675	3,675	—	3,375	3,375	—
Debentures (a):
2.25%, due 2022	250	—	250	250	—	250
3.05%, due 2027	300	—	300	300	—	300
3%, due 2029	350	—	350	350	—	350
1.95%, due 2031 (c)	300	—	300	—	—	—
6.25%, due 2034	100	—	100	100	—	100
6.375%, due 2037	300	—	300	300	—	300
7.6%, due 2038	250	—	250	250	—	250
4.1%, due 2044	250	—	250	250	—	250
3.65%, due 2050	350	—	350	350	—	350
	2,450	—	2,450	2,150	—	2,150
Other:
AEF term loan credit agreement through March 2022, 1% at December 31, 2021 (with Alliant Energy as guarantor)	300	—	—	300	—	—
Corporate Services 3.45% senior notes, due 2022 (a)	75	—	—	75	—	—
AEF 3.75% senior notes, due 2023 (with Alliant Energy as guarantor) (a)	400	—	—	400	—	—
AEF 1.4% senior notes, due 2026 (with Alliant Energy as guarantor) (a)	200	—	—	200	—	—
AEF 4.25% senior notes, due 2028 (with Alliant Energy as guarantor) (a)	300	—	—	300	—	—
Sheboygan Power, LLC 5.06% senior secured notes, due 2022 to 2024 (secured by the Sheboygan Falls Energy Facility and related assets) (a)	24	—	—	31	—	—
Other, 1% at December 31, 2021, due 2022 to 2025	1	—	—	2	—	—
	1,300	—	—	1,308	—	—
Subtotal	7,425	3,675	2,450	6,833	3,375	2,150
Current maturities	(633)	—	(250)	(8)	—	—
Unamortized debt issuance costs	(42)	(23)	(15)	(41)	(22)	(14)
Unamortized debt (discount) and premium, net	(15)	(9)	(6)	(15)	(8)	(6)
Long-term debt, net (d)	$6,735	$3,643	$2,179	$6,769	$3,345	$2,130

(a)Contains optional redemption provisions which, if elected by the issuer at its sole discretion, could require material redemption premium payments by the issuer. The redemption premium payments under these optional redemption provisions are variable and dependent on applicable U.S. Treasury rates at the time of redemption.

(b)In November 2021, IPL issued $300 million of 3.1% senior debentures due 2051. The net proceeds from the issuance were used by IPL to retire its cumulative preferred stock in 2021 and for general corporate purposes.

(c)In September 2021, WPL issued $300 million of 1.95% debentures due 2031. The debentures were issued as green bonds, and an amount in excess of the net proceeds was disbursed for the construction and development of WPL’s wind and solar EGUs.

(d)There were no significant sinking fund requirements related to the outstanding long-term debt.

Schedule of Maturities of Long-term Debt

At December 31, 2021, long-term debt maturities for 2022 through 2026 were as follows (in millions):

	2022	2023	2024	2025	2026
IPL	$—	$—	$500	$300	$—
WPL	250	—	—	—	—
Corporate Services	75	—	—	—	—
AEF	308	408	9	—	200
Alliant Energy	$633	$408	$509	$300	$200

XML

Leases (Tables)

12 Months Ended

Dec. 31, 2021

Leases [Line Items]

Schedule of Operating Lease Details

Operating lease details are as follows (dollars in millions):

	December 31, 2021			December 31, 2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Property, plant and equipment, net	$14	$9	$5	$15	$9	$6
Other current liabilities	$2	$1	$1	$2	$1	$1
Other liabilities	12	8	4	13	8	5
Total operating lease liabilities	$14	$9	$5	$15	$9	$6
Weighted average remaining lease term	9 years	11 years	8 years	10 years	11 years	9 years
Weighted average discount rate	4%	4%	4%	4%	4%	4%

Schedule of Finance Lease Details

Finance lease details are as follows (dollars in millions):

	Alliant Energy	WPL
	December 31, 2021	December 31, 2021	December 31, 2020
Property, plant and equipment, net:
Sheboygan Falls Energy Facility	n/a	$21	$27
Leased land for solar generation	$11	11	—
	$11	$32	$27
Other current liabilities:
Sheboygan Falls Energy Facility	n/a	$10	$9
Leased land for solar generation	$1	1	—
	1	11	9
Other liabilities:
Sheboygan Falls Energy Facility	n/a	31	42
Leased land for solar generation	11	11	—
	11	42	42
Total finance lease liabilities	$12	$53	$51
Weighted average remaining lease term	34 years	10 years	4 years
Weighted average discount rate	3%	9%	11%
	2021	2021	2020	2019
Depreciation and amortization expenses	$—	$6	$6	$6
Interest expense	—	5	6	7
Total finance lease expense	$—	$11	$12	$13

Schedule of Operating Lease Liability Maturities

As of December 31, 2021, expected maturities of lease liabilities were as follows (in millions):

	2022	2023	2024	2025	2026	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$2	$2	$2	$2	$2	$7	$17	$3	$14
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	1	6	1	5
Finance Leases:
Alliant Energy	—	—	—	—	1	19	20	8	12
WPL	15	15	15	6	1	19	71	18	53

Schedule of Finance Lease Liability Maturities

As of December 31, 2021, expected maturities of lease liabilities were as follows (in millions):

	2022	2023	2024	2025	2026	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$2	$2	$2	$2	$2	$7	$17	$3	$14
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	1	6	1	5
Finance Leases:
Alliant Energy	—	—	—	—	1	19	20	8	12
WPL	15	15	15	6	1	19	71	18	53

IPL [Member]

Leases [Line Items]

Schedule of Operating Lease Details

Operating lease details are as follows (dollars in millions):

	December 31, 2021			December 31, 2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Property, plant and equipment, net	$14	$9	$5	$15	$9	$6
Other current liabilities	$2	$1	$1	$2	$1	$1
Other liabilities	12	8	4	13	8	5
Total operating lease liabilities	$14	$9	$5	$15	$9	$6
Weighted average remaining lease term	9 years	11 years	8 years	10 years	11 years	9 years
Weighted average discount rate	4%	4%	4%	4%	4%	4%

Schedule of Operating Lease Liability Maturities

As of December 31, 2021, expected maturities of lease liabilities were as follows (in millions):

	2022	2023	2024	2025	2026	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$2	$2	$2	$2	$2	$7	$17	$3	$14
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	1	6	1	5
Finance Leases:
Alliant Energy	—	—	—	—	1	19	20	8	12
WPL	15	15	15	6	1	19	71	18	53

WPL [Member]

Leases [Line Items]

Schedule of Operating Lease Details

Operating lease details are as follows (dollars in millions):

	December 31, 2021			December 31, 2020
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Property, plant and equipment, net	$14	$9	$5	$15	$9	$6
Other current liabilities	$2	$1	$1	$2	$1	$1
Other liabilities	12	8	4	13	8	5
Total operating lease liabilities	$14	$9	$5	$15	$9	$6
Weighted average remaining lease term	9 years	11 years	8 years	10 years	11 years	9 years
Weighted average discount rate	4%	4%	4%	4%	4%	4%

Schedule of Finance Lease Details

Finance lease details are as follows (dollars in millions):

	Alliant Energy	WPL
	December 31, 2021	December 31, 2021	December 31, 2020
Property, plant and equipment, net:
Sheboygan Falls Energy Facility	n/a	$21	$27
Leased land for solar generation	$11	11	—
	$11	$32	$27
Other current liabilities:
Sheboygan Falls Energy Facility	n/a	$10	$9
Leased land for solar generation	$1	1	—
	1	11	9
Other liabilities:
Sheboygan Falls Energy Facility	n/a	31	42
Leased land for solar generation	11	11	—
	11	42	42
Total finance lease liabilities	$12	$53	$51
Weighted average remaining lease term	34 years	10 years	4 years
Weighted average discount rate	3%	9%	11%
	2021	2021	2020	2019
Depreciation and amortization expenses	$—	$6	$6	$6
Interest expense	—	5	6	7
Total finance lease expense	$—	$11	$12	$13

Schedule of Operating Lease Liability Maturities

As of December 31, 2021, expected maturities of lease liabilities were as follows (in millions):

	2022	2023	2024	2025	2026	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$2	$2	$2	$2	$2	$7	$17	$3	$14
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	1	6	1	5
Finance Leases:
Alliant Energy	—	—	—	—	1	19	20	8	12
WPL	15	15	15	6	1	19	71	18	53

Schedule of Finance Lease Liability Maturities

As of December 31, 2021, expected maturities of lease liabilities were as follows (in millions):

	2022	2023	2024	2025	2026	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$2	$2	$2	$2	$2	$7	$17	$3	$14
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	1	6	1	5
Finance Leases:
Alliant Energy	—	—	—	—	1	19	20	8	12
WPL	15	15	15	6	1	19	71	18	53

XML

Revenues (Tables)

12 Months Ended

Dec. 31, 2021

Disaggregation of Revenue [Line Items]

Disaggregation of Revenues

Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Electric Utility:
Retail - residential	$1,115	$1,093	$1,092	$620	$602	$601	$495	$491	$491
Retail - commercial	763	718	770	508	474	510	255	244	260
Retail - industrial	893	841	889	505	488	504	388	353	385
Wholesale	187	168	177	57	57	64	130	111	113
Bulk power and other	123	100	136	62	74	102	61	26	34
Total Electric Utility	3,081	2,920	3,064	1,752	1,695	1,781	1,329	1,225	1,283
Gas Utility:
Retail - residential	257	214	259	146	116	149	111	98	110
Retail - commercial	139	107	133	79	59	75	60	48	58
Retail - industrial	17	12	16	12	8	12	5	4	4
Transportation/other	43	40	47	28	25	28	15	15	19
Total Gas Utility	456	373	455	265	208	264	191	165	191
Other Utility:
Steam	36	36	37	36	36	37	—	—	—
Other utility	13	13	9	10	8	7	3	5	2
Total Other Utility	49	49	46	46	44	44	3	5	2
Non-Utility and Other:
Travero and other	83	74	83	—	—	—	—	—	—
Total Non-Utility and Other	83	74	83	—	—	—	—	—	—
Total revenues	$3,669	$3,416	$3,648	$2,063	$1,947	$2,089	$1,523	$1,395	$1,476

IPL [Member]

Disaggregation of Revenue [Line Items]

Disaggregation of Revenues

Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Electric Utility:
Retail - residential	$1,115	$1,093	$1,092	$620	$602	$601	$495	$491	$491
Retail - commercial	763	718	770	508	474	510	255	244	260
Retail - industrial	893	841	889	505	488	504	388	353	385
Wholesale	187	168	177	57	57	64	130	111	113
Bulk power and other	123	100	136	62	74	102	61	26	34
Total Electric Utility	3,081	2,920	3,064	1,752	1,695	1,781	1,329	1,225	1,283
Gas Utility:
Retail - residential	257	214	259	146	116	149	111	98	110
Retail - commercial	139	107	133	79	59	75	60	48	58
Retail - industrial	17	12	16	12	8	12	5	4	4
Transportation/other	43	40	47	28	25	28	15	15	19
Total Gas Utility	456	373	455	265	208	264	191	165	191
Other Utility:
Steam	36	36	37	36	36	37	—	—	—
Other utility	13	13	9	10	8	7	3	5	2
Total Other Utility	49	49	46	46	44	44	3	5	2
Non-Utility and Other:
Travero and other	83	74	83	—	—	—	—	—	—
Total Non-Utility and Other	83	74	83	—	—	—	—	—	—
Total revenues	$3,669	$3,416	$3,648	$2,063	$1,947	$2,089	$1,523	$1,395	$1,476

WPL [Member]

Disaggregation of Revenue [Line Items]

Disaggregation of Revenues

Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Electric Utility:
Retail - residential	$1,115	$1,093	$1,092	$620	$602	$601	$495	$491	$491
Retail - commercial	763	718	770	508	474	510	255	244	260
Retail - industrial	893	841	889	505	488	504	388	353	385
Wholesale	187	168	177	57	57	64	130	111	113
Bulk power and other	123	100	136	62	74	102	61	26	34
Total Electric Utility	3,081	2,920	3,064	1,752	1,695	1,781	1,329	1,225	1,283
Gas Utility:
Retail - residential	257	214	259	146	116	149	111	98	110
Retail - commercial	139	107	133	79	59	75	60	48	58
Retail - industrial	17	12	16	12	8	12	5	4	4
Transportation/other	43	40	47	28	25	28	15	15	19
Total Gas Utility	456	373	455	265	208	264	191	165	191
Other Utility:
Steam	36	36	37	36	36	37	—	—	—
Other utility	13	13	9	10	8	7	3	5	2
Total Other Utility	49	49	46	46	44	44	3	5	2
Non-Utility and Other:
Travero and other	83	74	83	—	—	—	—	—	—
Total Non-Utility and Other	83	74	83	—	—	—	—	—	—
Total revenues	$3,669	$3,416	$3,648	$2,063	$1,947	$2,089	$1,523	$1,395	$1,476

XML

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax [Line Items]

Schedule of Components of Income Tax Expense (Benefit)

The components of “Income tax expense (benefit)” in the income statements were as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Current tax expense (benefit):
Federal	$1	$1	($7)	($21)	$6	($11)	$22	($11)	$12
State	3	8	24	(1)	(1)	24	6	7	13
IPL’s tax benefit riders	—	—	(4)	—	—	(4)	—	—	—
Deferred tax expense (benefit):
Federal	9	22	70	73	30	26	(75)	(9)	31
State	15	8	42	—	(2)	31	11	10	6
Production tax credits	(101)	(95)	(55)	(87)	(80)	(42)	(14)	(15)	(13)
Investment tax credits	(1)	(1)	(1)	—	—	—	(1)	(1)	—
	($74)	($57)	$69	($36)	($47)	$24	($51)	($19)	$49

Schedule Of Effective Income Tax Rates

The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	Alliant Energy						IPL						WPL
	2021		2020		2019		2021		2020		2019		2021		2020		2019
Statutory federal income tax rate	21	%	21	%	21	%	21	%	21	%	21	%	21	%	21	%	21	%
State income taxes, net of federal benefits	2		2		7		(1)		(1)		8		6		6		6
Amortization of excess deferred taxes (Refer to Note 2)	(18)		(13)		(1)		(4)		(5)		—		(43)		(26)		(2)
Production tax credits	(17)		(17)		(9)		(27)		(28)		(13)		(6)		(7)		(5)
Effect of rate-making on property-related differences	(1)		(3)		(6)		(2)		(4)		(10)		(1)		(2)		(3)
Adjustment for prior period taxes	1		1		1		2		1		3		—		—		—
IPL’s tax benefit riders	—		—		(1)		—		—		(1)		—		—		—
Other items, net	—		(1)		(1)		—		—		—		(1)		—		—
Overall income tax rate	(12	%)	(10	%)	11	%	(11	%)	(16	%)	8	%	(24	%)	(8	%)	17	%

Schedule of Deferred Tax Assets and Liabilities

The deferred tax assets and liabilities included on the balance sheets at December 31 arise from the following temporary differences (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Deferred tax liabilities:
Property	$2,389	$2,232	$1,416	$1,312	$913	$854
ATC Holdings	123	116	—	—	—	—
Other	111	101	76	83	50	41
Total deferred tax liabilities	2,623	2,449	1,492	1,395	963	895
Deferred tax assets:
Federal credit carryforwards	560	454	345	258	192	175
Net operating losses carryforwards - federal	39	77	36	71	—	1
Net operating losses carryforwards - state	38	37	3	1	—	—
Other	65	73	25	30	18	18
Subtotal deferred tax assets	702	641	409	360	210	194
Valuation allowances	(6)	(6)	—	—	—	(1)
Total deferred tax assets	696	635	409	360	210	193
Total deferred tax liabilities, net	$1,927	$1,814	$1,083	$1,035	$753	$702

Summary Of Tax Credit Carryforwards

At December 31, 2021, carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy	IPL	WPL
Federal net operating losses	2037	$186	$172	$1
State net operating losses	2022-2041	619	28	2
Federal tax credits	2022-2041	560	345	192

Schedule Of Open Tax Years

Tax years that remain subject to the statute of limitations in the major jurisdictions for each of Alliant Energy, IPL and WPL are as follows:

Consolidated federal income tax returns (a)	2018	-	2020
Consolidated Iowa income tax returns (b)	2018	-	2020
Wisconsin combined tax returns (c)	2017	-	2020

(a)The 2018 and 2019 federal tax returns are effectively settled as a result of participation in the IRS Compliance Assurance Program, which allows Alliant Energy and the IRS to work together to resolve issues related to Alliant Energy’s current tax year before filing its federal income tax return. The statute of limitations for these federal tax returns expires three years from each filing date.

(b)The statute of limitations for these Iowa tax returns expires three years from each filing date.

(c)The statute of limitations for these Wisconsin combined tax returns expires four years from each filing date.

IPL [Member]

Income Tax [Line Items]

Schedule of Components of Income Tax Expense (Benefit)

The components of “Income tax expense (benefit)” in the income statements were as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Current tax expense (benefit):
Federal	$1	$1	($7)	($21)	$6	($11)	$22	($11)	$12
State	3	8	24	(1)	(1)	24	6	7	13
IPL’s tax benefit riders	—	—	(4)	—	—	(4)	—	—	—
Deferred tax expense (benefit):
Federal	9	22	70	73	30	26	(75)	(9)	31
State	15	8	42	—	(2)	31	11	10	6
Production tax credits	(101)	(95)	(55)	(87)	(80)	(42)	(14)	(15)	(13)
Investment tax credits	(1)	(1)	(1)	—	—	—	(1)	(1)	—
	($74)	($57)	$69	($36)	($47)	$24	($51)	($19)	$49

Schedule Of Effective Income Tax Rates

The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	Alliant Energy						IPL						WPL
	2021		2020		2019		2021		2020		2019		2021		2020		2019
Statutory federal income tax rate	21	%	21	%	21	%	21	%	21	%	21	%	21	%	21	%	21	%
State income taxes, net of federal benefits	2		2		7		(1)		(1)		8		6		6		6
Amortization of excess deferred taxes (Refer to Note 2)	(18)		(13)		(1)		(4)		(5)		—		(43)		(26)		(2)
Production tax credits	(17)		(17)		(9)		(27)		(28)		(13)		(6)		(7)		(5)
Effect of rate-making on property-related differences	(1)		(3)		(6)		(2)		(4)		(10)		(1)		(2)		(3)
Adjustment for prior period taxes	1		1		1		2		1		3		—		—		—
IPL’s tax benefit riders	—		—		(1)		—		—		(1)		—		—		—
Other items, net	—		(1)		(1)		—		—		—		(1)		—		—
Overall income tax rate	(12	%)	(10	%)	11	%	(11	%)	(16	%)	8	%	(24	%)	(8	%)	17	%

Schedule of Deferred Tax Assets and Liabilities

The deferred tax assets and liabilities included on the balance sheets at December 31 arise from the following temporary differences (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Deferred tax liabilities:
Property	$2,389	$2,232	$1,416	$1,312	$913	$854
ATC Holdings	123	116	—	—	—	—
Other	111	101	76	83	50	41
Total deferred tax liabilities	2,623	2,449	1,492	1,395	963	895
Deferred tax assets:
Federal credit carryforwards	560	454	345	258	192	175
Net operating losses carryforwards - federal	39	77	36	71	—	1
Net operating losses carryforwards - state	38	37	3	1	—	—
Other	65	73	25	30	18	18
Subtotal deferred tax assets	702	641	409	360	210	194
Valuation allowances	(6)	(6)	—	—	—	(1)
Total deferred tax assets	696	635	409	360	210	193
Total deferred tax liabilities, net	$1,927	$1,814	$1,083	$1,035	$753	$702

Summary Of Tax Credit Carryforwards

At December 31, 2021, carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy	IPL	WPL
Federal net operating losses	2037	$186	$172	$1
State net operating losses	2022-2041	619	28	2
Federal tax credits	2022-2041	560	345	192

Schedule Of Open Tax Years

Tax years that remain subject to the statute of limitations in the major jurisdictions for each of Alliant Energy, IPL and WPL are as follows:

Consolidated federal income tax returns (a)	2018	-	2020
Consolidated Iowa income tax returns (b)	2018	-	2020
Wisconsin combined tax returns (c)	2017	-	2020

(a)The 2018 and 2019 federal tax returns are effectively settled as a result of participation in the IRS Compliance Assurance Program, which allows Alliant Energy and the IRS to work together to resolve issues related to Alliant Energy’s current tax year before filing its federal income tax return. The statute of limitations for these federal tax returns expires three years from each filing date.

(b)The statute of limitations for these Iowa tax returns expires three years from each filing date.

(c)The statute of limitations for these Wisconsin combined tax returns expires four years from each filing date.

WPL [Member]

Income Tax [Line Items]

Schedule of Components of Income Tax Expense (Benefit)

The components of “Income tax expense (benefit)” in the income statements were as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Current tax expense (benefit):
Federal	$1	$1	($7)	($21)	$6	($11)	$22	($11)	$12
State	3	8	24	(1)	(1)	24	6	7	13
IPL’s tax benefit riders	—	—	(4)	—	—	(4)	—	—	—
Deferred tax expense (benefit):
Federal	9	22	70	73	30	26	(75)	(9)	31
State	15	8	42	—	(2)	31	11	10	6
Production tax credits	(101)	(95)	(55)	(87)	(80)	(42)	(14)	(15)	(13)
Investment tax credits	(1)	(1)	(1)	—	—	—	(1)	(1)	—
	($74)	($57)	$69	($36)	($47)	$24	($51)	($19)	$49

Schedule Of Effective Income Tax Rates

The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	Alliant Energy						IPL						WPL
	2021		2020		2019		2021		2020		2019		2021		2020		2019
Statutory federal income tax rate	21	%	21	%	21	%	21	%	21	%	21	%	21	%	21	%	21	%
State income taxes, net of federal benefits	2		2		7		(1)		(1)		8		6		6		6
Amortization of excess deferred taxes (Refer to Note 2)	(18)		(13)		(1)		(4)		(5)		—		(43)		(26)		(2)
Production tax credits	(17)		(17)		(9)		(27)		(28)		(13)		(6)		(7)		(5)
Effect of rate-making on property-related differences	(1)		(3)		(6)		(2)		(4)		(10)		(1)		(2)		(3)
Adjustment for prior period taxes	1		1		1		2		1		3		—		—		—
IPL’s tax benefit riders	—		—		(1)		—		—		(1)		—		—		—
Other items, net	—		(1)		(1)		—		—		—		(1)		—		—
Overall income tax rate	(12	%)	(10	%)	11	%	(11	%)	(16	%)	8	%	(24	%)	(8	%)	17	%

Schedule of Deferred Tax Assets and Liabilities

The deferred tax assets and liabilities included on the balance sheets at December 31 arise from the following temporary differences (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Deferred tax liabilities:
Property	$2,389	$2,232	$1,416	$1,312	$913	$854
ATC Holdings	123	116	—	—	—	—
Other	111	101	76	83	50	41
Total deferred tax liabilities	2,623	2,449	1,492	1,395	963	895
Deferred tax assets:
Federal credit carryforwards	560	454	345	258	192	175
Net operating losses carryforwards - federal	39	77	36	71	—	1
Net operating losses carryforwards - state	38	37	3	1	—	—
Other	65	73	25	30	18	18
Subtotal deferred tax assets	702	641	409	360	210	194
Valuation allowances	(6)	(6)	—	—	—	(1)
Total deferred tax assets	696	635	409	360	210	193
Total deferred tax liabilities, net	$1,927	$1,814	$1,083	$1,035	$753	$702

Summary Of Tax Credit Carryforwards

At December 31, 2021, carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy	IPL	WPL
Federal net operating losses	2037	$186	$172	$1
State net operating losses	2022-2041	619	28	2
Federal tax credits	2022-2041	560	345	192

Schedule Of Open Tax Years

Tax years that remain subject to the statute of limitations in the major jurisdictions for each of Alliant Energy, IPL and WPL are as follows:

Consolidated federal income tax returns (a)	2018	-	2020
Consolidated Iowa income tax returns (b)	2018	-	2020
Wisconsin combined tax returns (c)	2017	-	2020

(a)The 2018 and 2019 federal tax returns are effectively settled as a result of participation in the IRS Compliance Assurance Program, which allows Alliant Energy and the IRS to work together to resolve issues related to Alliant Energy’s current tax year before filing its federal income tax return. The statute of limitations for these federal tax returns expires three years from each filing date.

(b)The statute of limitations for these Iowa tax returns expires three years from each filing date.

(c)The statute of limitations for these Wisconsin combined tax returns expires four years from each filing date.

XML

Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2021

Defined Benefit Plan Disclosure [Line Items]

Assumptions Used To Measure Benefit Plans

The assumptions for defined benefit pension and OPEB plans at the measurement date of December 31 were as follows:

	Defined Benefit Pension Plans									OPEB Plans
Alliant Energy	2021			2020			2019			2021	2020	2019
Discount rate for benefit obligations	2.91%			2.57%			3.48%			2.81%	2.31%	3.40%
Discount rate for net periodic cost	2.57%			3.48%			4.34%			2.31%	3.40%	4.24%
Expected rate of return on plan assets	7.10%			7.10%			7.60%			4.80%	4.50%	5.44%
Interest crediting rate for Alliant Energy Cash Balance Pension Plan	4.18%			4.76%			5.52%			N/A	N/A	N/A
Rate of compensation increase	3.30%	-	4.50%	3.65%	-	4.50%	3.65%	-	4.50%	N/A	N/A	N/A

	Qualified Defined Benefit Pension Plan			OPEB Plans
IPL	2021	2020	2019	2021	2020	2019
Discount rate for benefit obligations	2.94%	2.61%	3.51%	2.80%	2.28%	3.39%
Discount rate for net periodic cost	2.61%	3.51%	4.35%	2.28%	3.39%	4.23%
Expected rate of return on plan assets	7.10%	7.10%	7.60%	5.10%	4.50%	5.60%
Rate of compensation increase	3.30%	3.65%	3.65%	N/A	N/A	N/A

	Qualified Defined Benefit Pension Plan			OPEB Plans
WPL	2021	2020	2019	2021	2020	2019
Discount rate for benefit obligations	2.94%	2.64%	3.50%	2.79%	2.27%	3.39%
Discount rate for net periodic cost	2.64%	3.50%	4.35%	2.27%	3.39%	4.23%
Expected rate of return on plan assets	7.10%	7.10%	7.60%	4.02%	3.28%	3.81%
Rate of compensation increase	3.30%	3.65%	3.65%	N/A	N/A	N/A

Net Periodic Benefit Costs

The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans are included below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements.

Alliant Energy	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$11	$11	$10	$4	$3	$3
Interest cost	34	43	50	5	7	9
Expected return on plan assets (a)	(69)	(70)	(60)	(5)	(5)	(5)
Amortization of prior service credit (b)	—	—	(1)	—	—	—
Amortization of actuarial loss (c)	39	34	36	5	3	3
Settlement losses (d)	—	12	—	—	—	—
	$15	$30	$35	$9	$8	$10

IPL	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$7	$7	$6	$1	$1	$1
Interest cost	16	20	23	2	3	3
Expected return on plan assets (a)	(32)	(33)	(28)	(3)	(4)	(4)
Amortization of actuarial loss (c)	17	15	15	2	1	2
Settlement losses (d)	—	7	—	—	—	—
	$8	$16	$16	$2	$1	$2

WPL	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$4	$4	$3	$1	$2	$1
Interest cost	15	19	21	2	3	3
Expected return on plan assets (a)	(31)	(31)	(26)	—	(1)	(1)
Amortization of prior service credit (b)	—	—	—	—	(1)	—
Amortization of actuarial loss (c)	19	16	18	2	2	2
	$7	$8	$16	$5	$5	$5

(a)The expected return on plan assets is based on the expected rate of return on plan assets and the fair value approach to the market-related value of plan assets.

(b)Unrecognized prior service credits for the OPEB plans are amortized over the average future service period to full eligibility of the participants of each plan.

(c)Unrecognized net actuarial gains or losses in excess of 10% of the greater of the plans’ benefit obligations or assets are amortized over the average future service lives of plan participants, except for the Alliant Energy Cash Balance Pension Plan where gains or losses outside the 10% threshold are amortized over the time period the participants are expected to receive benefits.

(d)Settlement losses related to payments made to retired executives of Alliant Energy and lump sum payments related to IPL’s qualified defined benefit pension plan.

Funded Status Of Benefit Plans

A reconciliation of the funded status of qualified and non-qualified defined benefit pension and OPEB plans to the amounts recognized on the balance sheets at December 31 was as follows (in millions):

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$1,351	$1,280	$227	$214
Service cost	11	11	4	3
Interest cost	34	43	5	7
Plan participants’ contributions	—	—	5	4
Actuarial (gain) loss	(46)	132	(12)	18
Gross benefits paid	(99)	(115)	(19)	(19)
Net benefit obligation at December 31	1,251	1,351	210	227
Change in plan assets:
Fair value of plan assets at January 1	984	931	108	105
Actual return on plan assets	87	108	4	11
Employer contributions	39	60	8	7
Plan participants’ contributions	—	—	5	4
Gross benefits paid	(99)	(115)	(19)	(19)
Fair value of plan assets at December 31	1,011	984	106	108
Under funded status at December 31	($240)	($367)	($104)	($119)

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$13	$8
Current liabilities	(2)	(2)	(8)	(8)
Pension and other benefit obligations	(238)	(365)	(109)	(119)
Net amounts recognized at December 31	($240)	($367)	($104)	($119)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$429	$533	$38	$54
Prior service credit	(4)	(5)	(1)	(1)
	$425	$528	$37	$53

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$615	$581	$91	$86
Service cost	7	7	1	1
Interest cost	16	20	2	3
Plan participants’ contributions	—	—	2	1
Actuarial (gain) loss	(23)	60	(4)	8
Gross benefits paid	(48)	(53)	(8)	(8)
Net benefit obligation at December 31	567	615	84	91
Change in plan assets:
Fair value of plan assets at January 1	453	436	74	72
Actual return on plan assets	40	51	4	7
Employer contributions	17	19	2	2
Plan participants’ contributions	—	—	2	1
Gross benefits paid	(48)	(53)	(8)	(8)
Fair value of plan assets at December 31	462	453	74	74
Under funded status at December 31	($105)	($162)	($10)	($17)

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$10	$4
Current liabilities	—	(1)	(2)	(2)
Pension and other benefit obligations	(105)	(161)	(18)	(19)
Net amounts recognized at December 31	($105)	($162)	($10)	($17)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$180	$228	$13	$20
Prior service credit	(1)	(1)	—	—
	$179	$227	$13	$20

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$588	$550	$89	$85
Service cost	4	4	1	2
Interest cost	15	19	2	3
Plan participants’ contributions	—	—	2	2
Actuarial (gain) loss	(18)	55	(5)	5
Gross benefits paid	(43)	(40)	(8)	(8)
Net benefit obligation at December 31	546	588	81	89
Change in plan assets:
Fair value of plan assets at January 1	436	406	18	17
Actual return on plan assets	39	48	—	2
Employer contributions	18	22	5	5
Plan participants’ contributions	—	—	2	2
Gross benefits paid	(43)	(40)	(8)	(8)
Fair value of plan assets at December 31	450	436	17	18
Under funded status at December 31	($96)	($152)	($64)	($71)

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$3	$3
Current liabilities	—	—	(6)	(6)
Pension and other benefit obligations	(96)	(152)	(61)	(68)
Net amounts recognized at December 31	($96)	($152)	($64)	($71)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$188	$233	$18	$25
Prior service credit	(1)	(1)	(1)	(1)
	$187	$232	$17	$24

Accumulated Benefit Obligations

Accumulated benefit obligations, aggregate amounts applicable to defined benefit pension and OPEB plans with accumulated benefit obligations in excess of plan assets, as well as defined benefit pension plans with projected benefit obligations in excess of plan assets as of the December 31 measurement date are as follows (in millions):

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Accumulated benefit obligations	$1,214	$1,305	$210	$227
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	1,214	1,305	210	227
Fair value of plan assets	1,011	984	106	108
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	1,251	1,351	N/A	N/A
Fair value of plan assets	1,011	984	N/A	N/A

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Accumulated benefit obligations	$546	$589	$84	$91
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	546	589	84	91
Fair value of plan assets	462	453	74	74
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	567	615	N/A	N/A
Fair value of plan assets	462	453	N/A	N/A

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Accumulated benefit obligations	$532	$573	$81	$89
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	532	573	81	89
Fair value of plan assets	450	436	17	18
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	546	588	N/A	N/A
Fair value of plan assets	450	436	N/A	N/A

Regulatory Assets

In addition to the amounts recognized in regulatory assets in the above tables for IPL and WPL, regulatory assets were recognized for amounts associated with Corporate Services employees participating in other Alliant Energy sponsored benefit plans that were allocated to IPL and WPL at December 31 as follows (in millions):

	IPL		WPL
	2021	2020	2021	2020
Regulatory assets	$35	$44	$30	$34

Estimated Future Employer Contributions

Estimated funding for the qualified and non-qualified defined benefit pension and OPEB plans for 2022 is as follows (in millions):

	Alliant Energy	IPL	WPL
Defined benefit pension plans (a)	$2	$—	$—
OPEB plans	8	2	6

(a)Alliant Energy sponsors several non-qualified defined benefit pension plans that cover certain current and former key employees of IPL and WPL. Alliant Energy allocates pension costs to IPL and WPL for these plans. In addition, IPL and WPL amounts reflect funding for their non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.

Expected Benefit Payments

Expected benefit payments for the qualified and non-qualified defined benefit plans, which reflect expected future service, as appropriate, are as follows (in millions):

Alliant Energy	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$85	$83	$82	$82	$83	$387
OPEB	18	17	17	17	16	71
	$103	$100	$99	$99	$99	$458

IPL	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$41	$40	$39	$39	$38	$174
OPEB	7	7	7	7	7	28
	$48	$47	$46	$46	$45	$202

WPL	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$37	$36	$35	$35	$34	$163
OPEB	7	7	7	7	6	27
	$44	$43	$42	$42	$40	$190

Recognized Compensation Expense And Income Tax Benefits

A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Compensation expense	$14	$16	$26	$8	$9	$15	$6	$6	$10
Income tax benefits	4	4	7	2	2	4	2	2	3

Schedule of Carrying Value and Fair Market Value of the Deferred Compensation Obligation

At December 31, the carrying value of the deferred compensation obligation for the company stock account and the shares in the deferred compensation trust based on the historical value of the shares of Alliant Energy common stock contributed to the rabbi trust, and the fair market value of the shares held in the rabbi trust, were as follows (in millions):

	2021	2020
Carrying value	$12	$11
Fair market value	24	20

IPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Assumptions Used To Measure Benefit Plans

The assumptions for defined benefit pension and OPEB plans at the measurement date of December 31 were as follows:

	Defined Benefit Pension Plans									OPEB Plans
Alliant Energy	2021			2020			2019			2021	2020	2019
Discount rate for benefit obligations	2.91%			2.57%			3.48%			2.81%	2.31%	3.40%
Discount rate for net periodic cost	2.57%			3.48%			4.34%			2.31%	3.40%	4.24%
Expected rate of return on plan assets	7.10%			7.10%			7.60%			4.80%	4.50%	5.44%
Interest crediting rate for Alliant Energy Cash Balance Pension Plan	4.18%			4.76%			5.52%			N/A	N/A	N/A
Rate of compensation increase	3.30%	-	4.50%	3.65%	-	4.50%	3.65%	-	4.50%	N/A	N/A	N/A

	Qualified Defined Benefit Pension Plan			OPEB Plans
IPL	2021	2020	2019	2021	2020	2019
Discount rate for benefit obligations	2.94%	2.61%	3.51%	2.80%	2.28%	3.39%
Discount rate for net periodic cost	2.61%	3.51%	4.35%	2.28%	3.39%	4.23%
Expected rate of return on plan assets	7.10%	7.10%	7.60%	5.10%	4.50%	5.60%
Rate of compensation increase	3.30%	3.65%	3.65%	N/A	N/A	N/A

	Qualified Defined Benefit Pension Plan			OPEB Plans
WPL	2021	2020	2019	2021	2020	2019
Discount rate for benefit obligations	2.94%	2.64%	3.50%	2.79%	2.27%	3.39%
Discount rate for net periodic cost	2.64%	3.50%	4.35%	2.27%	3.39%	4.23%
Expected rate of return on plan assets	7.10%	7.10%	7.60%	4.02%	3.28%	3.81%
Rate of compensation increase	3.30%	3.65%	3.65%	N/A	N/A	N/A

Net Periodic Benefit Costs

The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans are included below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements.

Alliant Energy	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$11	$11	$10	$4	$3	$3
Interest cost	34	43	50	5	7	9
Expected return on plan assets (a)	(69)	(70)	(60)	(5)	(5)	(5)
Amortization of prior service credit (b)	—	—	(1)	—	—	—
Amortization of actuarial loss (c)	39	34	36	5	3	3
Settlement losses (d)	—	12	—	—	—	—
	$15	$30	$35	$9	$8	$10

IPL	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$7	$7	$6	$1	$1	$1
Interest cost	16	20	23	2	3	3
Expected return on plan assets (a)	(32)	(33)	(28)	(3)	(4)	(4)
Amortization of actuarial loss (c)	17	15	15	2	1	2
Settlement losses (d)	—	7	—	—	—	—
	$8	$16	$16	$2	$1	$2

WPL	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$4	$4	$3	$1	$2	$1
Interest cost	15	19	21	2	3	3
Expected return on plan assets (a)	(31)	(31)	(26)	—	(1)	(1)
Amortization of prior service credit (b)	—	—	—	—	(1)	—
Amortization of actuarial loss (c)	19	16	18	2	2	2
	$7	$8	$16	$5	$5	$5

(a)The expected return on plan assets is based on the expected rate of return on plan assets and the fair value approach to the market-related value of plan assets.

(b)Unrecognized prior service credits for the OPEB plans are amortized over the average future service period to full eligibility of the participants of each plan.

(c)Unrecognized net actuarial gains or losses in excess of 10% of the greater of the plans’ benefit obligations or assets are amortized over the average future service lives of plan participants, except for the Alliant Energy Cash Balance Pension Plan where gains or losses outside the 10% threshold are amortized over the time period the participants are expected to receive benefits.

(d)Settlement losses related to payments made to retired executives of Alliant Energy and lump sum payments related to IPL’s qualified defined benefit pension plan.

Funded Status Of Benefit Plans

A reconciliation of the funded status of qualified and non-qualified defined benefit pension and OPEB plans to the amounts recognized on the balance sheets at December 31 was as follows (in millions):

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$1,351	$1,280	$227	$214
Service cost	11	11	4	3
Interest cost	34	43	5	7
Plan participants’ contributions	—	—	5	4
Actuarial (gain) loss	(46)	132	(12)	18
Gross benefits paid	(99)	(115)	(19)	(19)
Net benefit obligation at December 31	1,251	1,351	210	227
Change in plan assets:
Fair value of plan assets at January 1	984	931	108	105
Actual return on plan assets	87	108	4	11
Employer contributions	39	60	8	7
Plan participants’ contributions	—	—	5	4
Gross benefits paid	(99)	(115)	(19)	(19)
Fair value of plan assets at December 31	1,011	984	106	108
Under funded status at December 31	($240)	($367)	($104)	($119)

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$13	$8
Current liabilities	(2)	(2)	(8)	(8)
Pension and other benefit obligations	(238)	(365)	(109)	(119)
Net amounts recognized at December 31	($240)	($367)	($104)	($119)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$429	$533	$38	$54
Prior service credit	(4)	(5)	(1)	(1)
	$425	$528	$37	$53

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$615	$581	$91	$86
Service cost	7	7	1	1
Interest cost	16	20	2	3
Plan participants’ contributions	—	—	2	1
Actuarial (gain) loss	(23)	60	(4)	8
Gross benefits paid	(48)	(53)	(8)	(8)
Net benefit obligation at December 31	567	615	84	91
Change in plan assets:
Fair value of plan assets at January 1	453	436	74	72
Actual return on plan assets	40	51	4	7
Employer contributions	17	19	2	2
Plan participants’ contributions	—	—	2	1
Gross benefits paid	(48)	(53)	(8)	(8)
Fair value of plan assets at December 31	462	453	74	74
Under funded status at December 31	($105)	($162)	($10)	($17)

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$10	$4
Current liabilities	—	(1)	(2)	(2)
Pension and other benefit obligations	(105)	(161)	(18)	(19)
Net amounts recognized at December 31	($105)	($162)	($10)	($17)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$180	$228	$13	$20
Prior service credit	(1)	(1)	—	—
	$179	$227	$13	$20

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$588	$550	$89	$85
Service cost	4	4	1	2
Interest cost	15	19	2	3
Plan participants’ contributions	—	—	2	2
Actuarial (gain) loss	(18)	55	(5)	5
Gross benefits paid	(43)	(40)	(8)	(8)
Net benefit obligation at December 31	546	588	81	89
Change in plan assets:
Fair value of plan assets at January 1	436	406	18	17
Actual return on plan assets	39	48	—	2
Employer contributions	18	22	5	5
Plan participants’ contributions	—	—	2	2
Gross benefits paid	(43)	(40)	(8)	(8)
Fair value of plan assets at December 31	450	436	17	18
Under funded status at December 31	($96)	($152)	($64)	($71)

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$3	$3
Current liabilities	—	—	(6)	(6)
Pension and other benefit obligations	(96)	(152)	(61)	(68)
Net amounts recognized at December 31	($96)	($152)	($64)	($71)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$188	$233	$18	$25
Prior service credit	(1)	(1)	(1)	(1)
	$187	$232	$17	$24

Accumulated Benefit Obligations

Accumulated benefit obligations, aggregate amounts applicable to defined benefit pension and OPEB plans with accumulated benefit obligations in excess of plan assets, as well as defined benefit pension plans with projected benefit obligations in excess of plan assets as of the December 31 measurement date are as follows (in millions):

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Accumulated benefit obligations	$1,214	$1,305	$210	$227
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	1,214	1,305	210	227
Fair value of plan assets	1,011	984	106	108
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	1,251	1,351	N/A	N/A
Fair value of plan assets	1,011	984	N/A	N/A

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Accumulated benefit obligations	$546	$589	$84	$91
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	546	589	84	91
Fair value of plan assets	462	453	74	74
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	567	615	N/A	N/A
Fair value of plan assets	462	453	N/A	N/A

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Accumulated benefit obligations	$532	$573	$81	$89
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	532	573	81	89
Fair value of plan assets	450	436	17	18
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	546	588	N/A	N/A
Fair value of plan assets	450	436	N/A	N/A

Regulatory Assets

In addition to the amounts recognized in regulatory assets in the above tables for IPL and WPL, regulatory assets were recognized for amounts associated with Corporate Services employees participating in other Alliant Energy sponsored benefit plans that were allocated to IPL and WPL at December 31 as follows (in millions):

	IPL		WPL
	2021	2020	2021	2020
Regulatory assets	$35	$44	$30	$34

Estimated Future Employer Contributions

Estimated funding for the qualified and non-qualified defined benefit pension and OPEB plans for 2022 is as follows (in millions):

	Alliant Energy	IPL	WPL
Defined benefit pension plans (a)	$2	$—	$—
OPEB plans	8	2	6

(a)Alliant Energy sponsors several non-qualified defined benefit pension plans that cover certain current and former key employees of IPL and WPL. Alliant Energy allocates pension costs to IPL and WPL for these plans. In addition, IPL and WPL amounts reflect funding for their non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.

Expected Benefit Payments

Expected benefit payments for the qualified and non-qualified defined benefit plans, which reflect expected future service, as appropriate, are as follows (in millions):

Alliant Energy	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$85	$83	$82	$82	$83	$387
OPEB	18	17	17	17	16	71
	$103	$100	$99	$99	$99	$458

IPL	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$41	$40	$39	$39	$38	$174
OPEB	7	7	7	7	7	28
	$48	$47	$46	$46	$45	$202

WPL	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$37	$36	$35	$35	$34	$163
OPEB	7	7	7	7	6	27
	$44	$43	$42	$42	$40	$190

Recognized Compensation Expense And Income Tax Benefits

A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Compensation expense	$14	$16	$26	$8	$9	$15	$6	$6	$10
Income tax benefits	4	4	7	2	2	4	2	2	3

WPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Assumptions Used To Measure Benefit Plans

The assumptions for defined benefit pension and OPEB plans at the measurement date of December 31 were as follows:

	Defined Benefit Pension Plans									OPEB Plans
Alliant Energy	2021			2020			2019			2021	2020	2019
Discount rate for benefit obligations	2.91%			2.57%			3.48%			2.81%	2.31%	3.40%
Discount rate for net periodic cost	2.57%			3.48%			4.34%			2.31%	3.40%	4.24%
Expected rate of return on plan assets	7.10%			7.10%			7.60%			4.80%	4.50%	5.44%
Interest crediting rate for Alliant Energy Cash Balance Pension Plan	4.18%			4.76%			5.52%			N/A	N/A	N/A
Rate of compensation increase	3.30%	-	4.50%	3.65%	-	4.50%	3.65%	-	4.50%	N/A	N/A	N/A

	Qualified Defined Benefit Pension Plan			OPEB Plans
IPL	2021	2020	2019	2021	2020	2019
Discount rate for benefit obligations	2.94%	2.61%	3.51%	2.80%	2.28%	3.39%
Discount rate for net periodic cost	2.61%	3.51%	4.35%	2.28%	3.39%	4.23%
Expected rate of return on plan assets	7.10%	7.10%	7.60%	5.10%	4.50%	5.60%
Rate of compensation increase	3.30%	3.65%	3.65%	N/A	N/A	N/A

	Qualified Defined Benefit Pension Plan			OPEB Plans
WPL	2021	2020	2019	2021	2020	2019
Discount rate for benefit obligations	2.94%	2.64%	3.50%	2.79%	2.27%	3.39%
Discount rate for net periodic cost	2.64%	3.50%	4.35%	2.27%	3.39%	4.23%
Expected rate of return on plan assets	7.10%	7.10%	7.60%	4.02%	3.28%	3.81%
Rate of compensation increase	3.30%	3.65%	3.65%	N/A	N/A	N/A

Net Periodic Benefit Costs

The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans are included below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements.

Alliant Energy	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$11	$11	$10	$4	$3	$3
Interest cost	34	43	50	5	7	9
Expected return on plan assets (a)	(69)	(70)	(60)	(5)	(5)	(5)
Amortization of prior service credit (b)	—	—	(1)	—	—	—
Amortization of actuarial loss (c)	39	34	36	5	3	3
Settlement losses (d)	—	12	—	—	—	—
	$15	$30	$35	$9	$8	$10

IPL	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$7	$7	$6	$1	$1	$1
Interest cost	16	20	23	2	3	3
Expected return on plan assets (a)	(32)	(33)	(28)	(3)	(4)	(4)
Amortization of actuarial loss (c)	17	15	15	2	1	2
Settlement losses (d)	—	7	—	—	—	—
	$8	$16	$16	$2	$1	$2

WPL	Defined Benefit Pension Plans			OPEB Plans
	2021	2020	2019	2021	2020	2019
Service cost	$4	$4	$3	$1	$2	$1
Interest cost	15	19	21	2	3	3
Expected return on plan assets (a)	(31)	(31)	(26)	—	(1)	(1)
Amortization of prior service credit (b)	—	—	—	—	(1)	—
Amortization of actuarial loss (c)	19	16	18	2	2	2
	$7	$8	$16	$5	$5	$5

(a)The expected return on plan assets is based on the expected rate of return on plan assets and the fair value approach to the market-related value of plan assets.

(b)Unrecognized prior service credits for the OPEB plans are amortized over the average future service period to full eligibility of the participants of each plan.

(c)Unrecognized net actuarial gains or losses in excess of 10% of the greater of the plans’ benefit obligations or assets are amortized over the average future service lives of plan participants, except for the Alliant Energy Cash Balance Pension Plan where gains or losses outside the 10% threshold are amortized over the time period the participants are expected to receive benefits.

(d)Settlement losses related to payments made to retired executives of Alliant Energy and lump sum payments related to IPL’s qualified defined benefit pension plan.

Funded Status Of Benefit Plans

A reconciliation of the funded status of qualified and non-qualified defined benefit pension and OPEB plans to the amounts recognized on the balance sheets at December 31 was as follows (in millions):

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$1,351	$1,280	$227	$214
Service cost	11	11	4	3
Interest cost	34	43	5	7
Plan participants’ contributions	—	—	5	4
Actuarial (gain) loss	(46)	132	(12)	18
Gross benefits paid	(99)	(115)	(19)	(19)
Net benefit obligation at December 31	1,251	1,351	210	227
Change in plan assets:
Fair value of plan assets at January 1	984	931	108	105
Actual return on plan assets	87	108	4	11
Employer contributions	39	60	8	7
Plan participants’ contributions	—	—	5	4
Gross benefits paid	(99)	(115)	(19)	(19)
Fair value of plan assets at December 31	1,011	984	106	108
Under funded status at December 31	($240)	($367)	($104)	($119)

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$13	$8
Current liabilities	(2)	(2)	(8)	(8)
Pension and other benefit obligations	(238)	(365)	(109)	(119)
Net amounts recognized at December 31	($240)	($367)	($104)	($119)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$429	$533	$38	$54
Prior service credit	(4)	(5)	(1)	(1)
	$425	$528	$37	$53

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$615	$581	$91	$86
Service cost	7	7	1	1
Interest cost	16	20	2	3
Plan participants’ contributions	—	—	2	1
Actuarial (gain) loss	(23)	60	(4)	8
Gross benefits paid	(48)	(53)	(8)	(8)
Net benefit obligation at December 31	567	615	84	91
Change in plan assets:
Fair value of plan assets at January 1	453	436	74	72
Actual return on plan assets	40	51	4	7
Employer contributions	17	19	2	2
Plan participants’ contributions	—	—	2	1
Gross benefits paid	(48)	(53)	(8)	(8)
Fair value of plan assets at December 31	462	453	74	74
Under funded status at December 31	($105)	($162)	($10)	($17)

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$10	$4
Current liabilities	—	(1)	(2)	(2)
Pension and other benefit obligations	(105)	(161)	(18)	(19)
Net amounts recognized at December 31	($105)	($162)	($10)	($17)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$180	$228	$13	$20
Prior service credit	(1)	(1)	—	—
	$179	$227	$13	$20

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Change in benefit obligation:
Net benefit obligation at January 1	$588	$550	$89	$85
Service cost	4	4	1	2
Interest cost	15	19	2	3
Plan participants’ contributions	—	—	2	2
Actuarial (gain) loss	(18)	55	(5)	5
Gross benefits paid	(43)	(40)	(8)	(8)
Net benefit obligation at December 31	546	588	81	89
Change in plan assets:
Fair value of plan assets at January 1	436	406	18	17
Actual return on plan assets	39	48	—	2
Employer contributions	18	22	5	5
Plan participants’ contributions	—	—	2	2
Gross benefits paid	(43)	(40)	(8)	(8)
Fair value of plan assets at December 31	450	436	17	18
Under funded status at December 31	($96)	($152)	($64)	($71)

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Amounts recognized on the balance sheets consist of:
Non-current assets	$—	$—	$3	$3
Current liabilities	—	—	(6)	(6)
Pension and other benefit obligations	(96)	(152)	(61)	(68)
Net amounts recognized at December 31	($96)	($152)	($64)	($71)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	$188	$233	$18	$25
Prior service credit	(1)	(1)	(1)	(1)
	$187	$232	$17	$24

Accumulated Benefit Obligations

Accumulated benefit obligations, aggregate amounts applicable to defined benefit pension and OPEB plans with accumulated benefit obligations in excess of plan assets, as well as defined benefit pension plans with projected benefit obligations in excess of plan assets as of the December 31 measurement date are as follows (in millions):

	Defined Benefit Pension Plans		OPEB Plans
Alliant Energy	2021	2020	2021	2020
Accumulated benefit obligations	$1,214	$1,305	$210	$227
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	1,214	1,305	210	227
Fair value of plan assets	1,011	984	106	108
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	1,251	1,351	N/A	N/A
Fair value of plan assets	1,011	984	N/A	N/A

	Defined Benefit Pension Plans		OPEB Plans
IPL	2021	2020	2021	2020
Accumulated benefit obligations	$546	$589	$84	$91
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	546	589	84	91
Fair value of plan assets	462	453	74	74
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	567	615	N/A	N/A
Fair value of plan assets	462	453	N/A	N/A

	Defined Benefit Pension Plans		OPEB Plans
WPL	2021	2020	2021	2020
Accumulated benefit obligations	$532	$573	$81	$89
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	532	573	81	89
Fair value of plan assets	450	436	17	18
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	546	588	N/A	N/A
Fair value of plan assets	450	436	N/A	N/A

Regulatory Assets

In addition to the amounts recognized in regulatory assets in the above tables for IPL and WPL, regulatory assets were recognized for amounts associated with Corporate Services employees participating in other Alliant Energy sponsored benefit plans that were allocated to IPL and WPL at December 31 as follows (in millions):

	IPL		WPL
	2021	2020	2021	2020
Regulatory assets	$35	$44	$30	$34

Estimated Future Employer Contributions

Estimated funding for the qualified and non-qualified defined benefit pension and OPEB plans for 2022 is as follows (in millions):

	Alliant Energy	IPL	WPL
Defined benefit pension plans (a)	$2	$—	$—
OPEB plans	8	2	6

(a)Alliant Energy sponsors several non-qualified defined benefit pension plans that cover certain current and former key employees of IPL and WPL. Alliant Energy allocates pension costs to IPL and WPL for these plans. In addition, IPL and WPL amounts reflect funding for their non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.

Expected Benefit Payments

Expected benefit payments for the qualified and non-qualified defined benefit plans, which reflect expected future service, as appropriate, are as follows (in millions):

Alliant Energy	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$85	$83	$82	$82	$83	$387
OPEB	18	17	17	17	16	71
	$103	$100	$99	$99	$99	$458

IPL	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$41	$40	$39	$39	$38	$174
OPEB	7	7	7	7	7	28
	$48	$47	$46	$46	$45	$202

WPL	2022	2023	2024	2025	2026	2027 - 2031
Defined benefit pension benefits	$37	$36	$35	$35	$34	$163
OPEB	7	7	7	7	6	27
	$44	$43	$42	$42	$40	$190

Recognized Compensation Expense And Income Tax Benefits

A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards was as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Compensation expense	$14	$16	$26	$8	$9	$15	$6	$6	$10
Income tax benefits	4	4	7	2	2	4	2	2	3

Pension Plans, Defined Benefit [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair Value Of Plan Assets By Asset Category, Fair Value Hierarchy Level and Allocations

At December 31, 2021, the current target ranges and actual allocations for the defined benefit pension plan assets were as follows:

	Target Range			Actual
	Allocation			Allocation
Cash and equivalents	0%	-	5%	3%
Equity securities - U.S.	14%	-	54%	34%
Equity securities - international	11%	-	31%	21%
Global asset securities	5%	-	15%	9%
Fixed income securities	25%	-	45%	33%

At December 31, the fair values of qualified and non-qualified defined benefit pension plan assets were as follows (in millions):

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
Alliant Energy	Value	1	2	3	Value	1	2	3
Cash and equivalents	$35	$—	$35	$—	$46	$—	$46	$—
Equity securities - U.S.	256	256	—	—	182	182	—	—
Equity securities - international	—	—	—	—	151	151	—	—
Global asset securities	52	52	—	—	45	45	—	—
Fixed income securities	191	47	144	—	134	56	78	—
Total assets in fair value hierarchy	534	$355	$179	$—	558	$434	$124	$—
Assets measured at net asset value	477				426
Accrued investment income	1				1
Due to brokers, net (pending trades with brokers)	(1)				(1)
Total pension plan assets	$1,011				$984

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
IPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$16	$—	$16	$—	$21	$—	$21	$—
Equity securities - U.S.	117	117	—	—	84	84	—	—
Equity securities - international	—	—	—	—	69	69	—	—
Global asset securities	24	24	—	—	21	21	—	—
Fixed income securities	87	21	66	—	62	26	36	—
Total assets in fair value hierarchy	244	$162	$82	$—	257	$200	$57	$—
Assets measured at net asset value	218				196
Total pension plan assets	$462				$453

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
WPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$16	$—	$16	$—	$20	$—	$20	$—
Equity securities - U.S.	114	114	—	—	81	81	—	—
Equity securities - international	—	—	—	—	67	67	—	—
Global asset securities	23	23	—	—	20	20	—	—
Fixed income securities	85	21	64	—	59	25	34	—
Total assets in fair value hierarchy	238	$158	$80	$—	247	$193	$54	$—
Assets measured at net asset value	212				189
Total pension plan assets	$450				$436

Pension Plans, Defined Benefit [Member] | IPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair Value Of Plan Assets By Asset Category, Fair Value Hierarchy Level and Allocations

At December 31, 2021, the current target ranges and actual allocations for the defined benefit pension plan assets were as follows:

	Target Range			Actual
	Allocation			Allocation
Cash and equivalents	0%	-	5%	3%
Equity securities - U.S.	14%	-	54%	34%
Equity securities - international	11%	-	31%	21%
Global asset securities	5%	-	15%	9%
Fixed income securities	25%	-	45%	33%

At December 31, the fair values of qualified and non-qualified defined benefit pension plan assets were as follows (in millions):

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
Alliant Energy	Value	1	2	3	Value	1	2	3
Cash and equivalents	$35	$—	$35	$—	$46	$—	$46	$—
Equity securities - U.S.	256	256	—	—	182	182	—	—
Equity securities - international	—	—	—	—	151	151	—	—
Global asset securities	52	52	—	—	45	45	—	—
Fixed income securities	191	47	144	—	134	56	78	—
Total assets in fair value hierarchy	534	$355	$179	$—	558	$434	$124	$—
Assets measured at net asset value	477				426
Accrued investment income	1				1
Due to brokers, net (pending trades with brokers)	(1)				(1)
Total pension plan assets	$1,011				$984

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
IPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$16	$—	$16	$—	$21	$—	$21	$—
Equity securities - U.S.	117	117	—	—	84	84	—	—
Equity securities - international	—	—	—	—	69	69	—	—
Global asset securities	24	24	—	—	21	21	—	—
Fixed income securities	87	21	66	—	62	26	36	—
Total assets in fair value hierarchy	244	$162	$82	$—	257	$200	$57	$—
Assets measured at net asset value	218				196
Total pension plan assets	$462				$453

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
WPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$16	$—	$16	$—	$20	$—	$20	$—
Equity securities - U.S.	114	114	—	—	81	81	—	—
Equity securities - international	—	—	—	—	67	67	—	—
Global asset securities	23	23	—	—	20	20	—	—
Fixed income securities	85	21	64	—	59	25	34	—
Total assets in fair value hierarchy	238	$158	$80	$—	247	$193	$54	$—
Assets measured at net asset value	212				189
Total pension plan assets	$450				$436

Pension Plans, Defined Benefit [Member] | WPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair Value Of Plan Assets By Asset Category, Fair Value Hierarchy Level and Allocations

At December 31, 2021, the current target ranges and actual allocations for the defined benefit pension plan assets were as follows:

	Target Range			Actual
	Allocation			Allocation
Cash and equivalents	0%	-	5%	3%
Equity securities - U.S.	14%	-	54%	34%
Equity securities - international	11%	-	31%	21%
Global asset securities	5%	-	15%	9%
Fixed income securities	25%	-	45%	33%

At December 31, the fair values of qualified and non-qualified defined benefit pension plan assets were as follows (in millions):

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
Alliant Energy	Value	1	2	3	Value	1	2	3
Cash and equivalents	$35	$—	$35	$—	$46	$—	$46	$—
Equity securities - U.S.	256	256	—	—	182	182	—	—
Equity securities - international	—	—	—	—	151	151	—	—
Global asset securities	52	52	—	—	45	45	—	—
Fixed income securities	191	47	144	—	134	56	78	—
Total assets in fair value hierarchy	534	$355	$179	$—	558	$434	$124	$—
Assets measured at net asset value	477				426
Accrued investment income	1				1
Due to brokers, net (pending trades with brokers)	(1)				(1)
Total pension plan assets	$1,011				$984

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
IPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$16	$—	$16	$—	$21	$—	$21	$—
Equity securities - U.S.	117	117	—	—	84	84	—	—
Equity securities - international	—	—	—	—	69	69	—	—
Global asset securities	24	24	—	—	21	21	—	—
Fixed income securities	87	21	66	—	62	26	36	—
Total assets in fair value hierarchy	244	$162	$82	$—	257	$200	$57	$—
Assets measured at net asset value	218				196
Total pension plan assets	$462				$453

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
WPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$16	$—	$16	$—	$20	$—	$20	$—
Equity securities - U.S.	114	114	—	—	81	81	—	—
Equity securities - international	—	—	—	—	67	67	—	—
Global asset securities	23	23	—	—	20	20	—	—
Fixed income securities	85	21	64	—	59	25	34	—
Total assets in fair value hierarchy	238	$158	$80	$—	247	$193	$54	$—
Assets measured at net asset value	212				189
Total pension plan assets	$450				$436

Other Postretirement Benefits Plans [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair Value Of Plan Assets By Asset Category, Fair Value Hierarchy Level and Allocations

At December 31, 2021, the current target ranges and actual allocations for VEBA trusts with assets greater than $5 million and the WPL 401(h) assets were as follows:

	Target Range			Actual
	Allocation			Allocation
Cash and equivalents	0%	-	5%	1%
Equity securities - U.S.	0%	-	55%	35%
Fixed income securities	40%	-	100%	64%

At December 31, the fair values of OPEB plan assets were as follows (in millions):

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
Alliant Energy	Value	1	2	3	Value	1	2	3
Cash and equivalents	$5	$—	$5	$—	$2	$—	$2	$—
Equity securities - U.S.	11	11	—	—	4	4	—	—
Equity securities - international	—	—	—	—	3	3	—	—
Global asset securities	1	1	—	—	—	—	—	—
Fixed income securities	60	58	2	—	72	71	1	—
Total assets in fair value hierarchy	77	$70	$7	$—	81	$78	$3	$—
Assets measured at net asset value	29				27
Total OPEB plan assets	$106				$108

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
IPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$1	$—	$1	$—	$1	$—	$1	$—
Equity securities - U.S.	8	8	—	—	—	—	—	—
Fixed income securities	42	42	—	—	51	51	—	—
Total assets in fair value hierarchy	51	$50	$1	$—	52	$51	$1	$—
Assets measured at net asset value	23				22
Total OPEB plan assets	$74				$74

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
WPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$1	$—	$1	$—	$—	$—	$—	$—
Equity securities - U.S.	1	1	—	—	—	—	—	—
Fixed income securities	15	15	—	—	18	18	—	—
Total OPEB plan assets	$17	$16	$1	$—	$18	$18	$—	$—

Other Postretirement Benefits Plans [Member] | IPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair Value Of Plan Assets By Asset Category, Fair Value Hierarchy Level and Allocations

At December 31, 2021, the current target ranges and actual allocations for VEBA trusts with assets greater than $5 million and the WPL 401(h) assets were as follows:

	Target Range			Actual
	Allocation			Allocation
Cash and equivalents	0%	-	5%	1%
Equity securities - U.S.	0%	-	55%	35%
Fixed income securities	40%	-	100%	64%

At December 31, the fair values of OPEB plan assets were as follows (in millions):

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
Alliant Energy	Value	1	2	3	Value	1	2	3
Cash and equivalents	$5	$—	$5	$—	$2	$—	$2	$—
Equity securities - U.S.	11	11	—	—	4	4	—	—
Equity securities - international	—	—	—	—	3	3	—	—
Global asset securities	1	1	—	—	—	—	—	—
Fixed income securities	60	58	2	—	72	71	1	—
Total assets in fair value hierarchy	77	$70	$7	$—	81	$78	$3	$—
Assets measured at net asset value	29				27
Total OPEB plan assets	$106				$108

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
IPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$1	$—	$1	$—	$1	$—	$1	$—
Equity securities - U.S.	8	8	—	—	—	—	—	—
Fixed income securities	42	42	—	—	51	51	—	—
Total assets in fair value hierarchy	51	$50	$1	$—	52	$51	$1	$—
Assets measured at net asset value	23				22
Total OPEB plan assets	$74				$74

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
WPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$1	$—	$1	$—	$—	$—	$—	$—
Equity securities - U.S.	1	1	—	—	—	—	—	—
Fixed income securities	15	15	—	—	18	18	—	—
Total OPEB plan assets	$17	$16	$1	$—	$18	$18	$—	$—

Other Postretirement Benefits Plans [Member] | WPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair Value Of Plan Assets By Asset Category, Fair Value Hierarchy Level and Allocations

At December 31, 2021, the current target ranges and actual allocations for VEBA trusts with assets greater than $5 million and the WPL 401(h) assets were as follows:

	Target Range			Actual
	Allocation			Allocation
Cash and equivalents	0%	-	5%	1%
Equity securities - U.S.	0%	-	55%	35%
Fixed income securities	40%	-	100%	64%

At December 31, the fair values of OPEB plan assets were as follows (in millions):

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
Alliant Energy	Value	1	2	3	Value	1	2	3
Cash and equivalents	$5	$—	$5	$—	$2	$—	$2	$—
Equity securities - U.S.	11	11	—	—	4	4	—	—
Equity securities - international	—	—	—	—	3	3	—	—
Global asset securities	1	1	—	—	—	—	—	—
Fixed income securities	60	58	2	—	72	71	1	—
Total assets in fair value hierarchy	77	$70	$7	$—	81	$78	$3	$—
Assets measured at net asset value	29				27
Total OPEB plan assets	$106				$108

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
IPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$1	$—	$1	$—	$1	$—	$1	$—
Equity securities - U.S.	8	8	—	—	—	—	—	—
Fixed income securities	42	42	—	—	51	51	—	—
Total assets in fair value hierarchy	51	$50	$1	$—	52	$51	$1	$—
Assets measured at net asset value	23				22
Total OPEB plan assets	$74				$74

	2021				2020
	Fair	Level	Level	Level	Fair	Level	Level	Level
WPL	Value	1	2	3	Value	1	2	3
Cash and equivalents	$1	$—	$1	$—	$—	$—	$—	$—
Equity securities - U.S.	1	1	—	—	—	—	—	—
Fixed income securities	15	15	—	—	18	18	—	—
Total OPEB plan assets	$17	$16	$1	$—	$18	$18	$—	$—

401(k) Savings Plan [Member]

Defined Benefit Plan Disclosure [Line Items]

Employees Participate In Defined Contribution Retirement Plans

Costs related to the 401(k) savings plans, which are partially based on the participants’ contributions and include allocated costs associated with Corporate Services employees for IPL and WPL, were as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
401(k) costs	$26	$25	$25	$13	$13	$13	$12	$12	$12

401(k) Savings Plan [Member] | IPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Employees Participate In Defined Contribution Retirement Plans

Costs related to the 401(k) savings plans, which are partially based on the participants’ contributions and include allocated costs associated with Corporate Services employees for IPL and WPL, were as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
401(k) costs	$26	$25	$25	$13	$13	$13	$12	$12	$12

401(k) Savings Plan [Member] | WPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Employees Participate In Defined Contribution Retirement Plans

Costs related to the 401(k) savings plans, which are partially based on the participants’ contributions and include allocated costs associated with Corporate Services employees for IPL and WPL, were as follows (in millions):

	Alliant Energy			IPL			WPL
	2021	2020	2019	2021	2020	2019	2021	2020	2019
401(k) costs	$26	$25	$25	$13	$13	$13	$12	$12	$12

Performance Shares Equity Awards [Member]

Defined Benefit Plan Disclosure [Line Items]

Schedule Of Equity-based Compensation Plans Activity

A summary of the 2021, 2020 and 2019 performance shares activity, with amounts representing the target number of awards, was as follows:

	2021		2020		2019
	Performance Shares - Equity	Weighted Average Grant Date Fair Value	Performance Shares - Equity	Weighted Average Grant Date Fair Value	Performance Shares - Equity	Weighted Average Grant Date Fair Value
Nonvested awards, January 1	129,156	$54.63	74,193	$47.44	—	$—
Granted	73,112	46.19	56,204	64.04	91,816	47.23
Forfeited	(5,839)	51.07	(1,241)	50.94	(17,623)	46.35
Nonvested awards, December 31	196,429	51.59	129,156	54.63	74,193	47.44

Performance Shares and Performance Units Liability Awards [Member]

Defined Benefit Plan Disclosure [Line Items]

Schedule Of Equity-based Compensation Plans Activity

A summary of these performance shares and performance units activity, with amounts representing the target number of awards, was as follows:

	Performance Shares (granted prior to 2019)			Performance Units (granted prior to 2019)
	2021	2020	2019	2021	2020	2019
Nonvested awards, January 1	68,307	131,872	203,188	16,801	34,574	57,761
Vested	(68,307)	(63,565)	(66,322)	(16,801)	(16,661)	(20,131)
Forfeited	—	—	(4,994)	—	(1,112)	(3,056)
Nonvested awards, December 31	—	68,307	131,872	—	16,801	34,574

Certain performance shares and performance units vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows:

	Performance Shares (granted prior to 2019)			Performance Units (granted prior to 2019)
	2021	2020	2019	2021	2020	2019
	2018 Grant	2017 Grant	2016 Grant	2018 Grant	2017 Grant	2016 Grant
Performance awards vested	68,307	63,565	66,322	16,801	16,661	20,131
Percentage of target number of performance awards	172.5%	155.0%	142.5%	172.5%	155.0%	142.5%
Aggregate payout value (in millions)	$7	$6	$4	$2	$2	$1
Payout - cash (in millions)	$5	$5	$4	$2	$2	$1
Payout - common stock shares issued	13,644	9,543	6,447	N/A	N/A	N/A

Restricted Stock Units Equity Awards [Member]

Defined Benefit Plan Disclosure [Line Items]

Schedule Of Equity-based Compensation Plans Activity

A summary of the 2021, 2020 and 2019 restricted stock units activity was as follows:

	2021		2020		2019
	Restricted Stock Units - Equity	Weighted Average Grant Date Fair Value	Restricted Stock Units - Equity	Weighted Average Grant Date Fair Value	Restricted Stock Units - Equity	Weighted Average Grant Date Fair Value
Nonvested units, January 1	146,549	$51.54	89,281	$46.04	—	$—
Granted	80,152	48.65	61,056	59.42	105,348	45.98
Forfeited	(8,882)	49.84	(3,788)	49.01	(16,067)	45.63
Nonvested units, December 31	217,819	50.54	146,549	51.54	89,281	46.04

Restricted Stock Unit Liability Awards [Member]

Defined Benefit Plan Disclosure [Line Items]

Schedule Of Equity-based Compensation Plans Activity

A summary of the restricted stock units granted prior to 2019 activity was as follows:

	2021	2020	2019
Nonvested units, January 1	58,550	113,033	174,163
Vested	(58,550)	(54,483)	(56,849)
Forfeited	—	—	(4,281)
Nonvested units, December 31	—	58,550	113,033

Performance Restricted Stock Units Equity Awards [Member]

Defined Benefit Plan Disclosure [Line Items]

Schedule Of Equity-based Compensation Plans Activity

A summary of the performance restricted stock units activity, with amounts representing the target number of units, was as follows:

	2021		2020		2019
	Units	Weighted Average Grant Date Fair Value	Units	Weighted Average Grant Date Fair Value	Units	Weighted Average Grant Date Fair Value
Nonvested units, January 1	197,463	$47.31	206,065	$41.50	203,188	$37.23
Granted	73,112	48.66	56,204	59.37	91,816	46.10
Vested	(68,307)	38.60	(63,565)	39.12	(66,322)	33.93
Forfeited	(5,839)	50.46	(1,241)	49.25	(22,617)	44.00
Nonvested units, December 31	196,429	50.74	197,463	47.31	206,065	41.50

XML

Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2021

Schedule of Asset Retirement Obligations [Line Items]

Reconciliation Of Changes In Asset Retirement Obligations (AROs)

A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Balance, January 1	$251	$196	$177	$134	$74	$62
Revisions in estimated cash flows	50	13	44	9	6	4
Liabilities settled	(17)	(13)	(13)	(9)	(4)	(4)
Liabilities incurred	3	48	—	38	3	10
Accretion expense	7	7	5	5	2	2
Balance, December 31	$294	$251	$213	$177	$81	$74

IPL [Member]

Schedule of Asset Retirement Obligations [Line Items]

Reconciliation Of Changes In Asset Retirement Obligations (AROs)

A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Balance, January 1	$251	$196	$177	$134	$74	$62
Revisions in estimated cash flows	50	13	44	9	6	4
Liabilities settled	(17)	(13)	(13)	(9)	(4)	(4)
Liabilities incurred	3	48	—	38	3	10
Accretion expense	7	7	5	5	2	2
Balance, December 31	$294	$251	$213	$177	$81	$74

WPL [Member]

Schedule of Asset Retirement Obligations [Line Items]

Reconciliation Of Changes In Asset Retirement Obligations (AROs)

A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Balance, January 1	$251	$196	$177	$134	$74	$62
Revisions in estimated cash flows	50	13	44	9	6	4
Liabilities settled	(17)	(13)	(13)	(9)	(4)	(4)
Liabilities incurred	3	48	—	38	3	10
Accretion expense	7	7	5	5	2	2
Balance, December 31	$294	$251	$213	$177	$81	$74

XML

Derivative Instruments (Tables)

12 Months Ended

Dec. 31, 2021

Derivative [Line Items]

Notional Amounts of Derivative Instruments

As of December 31, 2021, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):

	FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	9,135	2022	191,670	2022-2030	3,193	2022-2023	3,024	2022
IPL	2,647	2022	100,560	2022-2030	1,270	2022-2023	—	—
WPL	6,488	2022	91,110	2022-2030	1,923	2022-2023	3,024	2022

Fair Value of Financial Instruments

At December 31, the fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Current derivative assets	$113	$24	$48	$20	$65	$4
Non-current derivative assets	63	10	36	9	27	1
Current derivative liabilities	8	9	4	3	4	6
Non-current derivative liabilities	1	16	—	9	1	7

IPL [Member]

Derivative [Line Items]

Notional Amounts of Derivative Instruments

As of December 31, 2021, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):

	FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	9,135	2022	191,670	2022-2030	3,193	2022-2023	3,024	2022
IPL	2,647	2022	100,560	2022-2030	1,270	2022-2023	—	—
WPL	6,488	2022	91,110	2022-2030	1,923	2022-2023	3,024	2022

Fair Value of Financial Instruments

At December 31, the fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Current derivative assets	$113	$24	$48	$20	$65	$4
Non-current derivative assets	63	10	36	9	27	1
Current derivative liabilities	8	9	4	3	4	6
Non-current derivative liabilities	1	16	—	9	1	7

WPL [Member]

Derivative [Line Items]

Notional Amounts of Derivative Instruments

As of December 31, 2021, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):

	FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	9,135	2022	191,670	2022-2030	3,193	2022-2023	3,024	2022
IPL	2,647	2022	100,560	2022-2030	1,270	2022-2023	—	—
WPL	6,488	2022	91,110	2022-2030	1,923	2022-2023	3,024	2022

Fair Value of Financial Instruments

At December 31, the fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions):

	Alliant Energy		IPL		WPL
	2021	2020	2021	2020	2021	2020
Current derivative assets	$113	$24	$48	$20	$65	$4
Non-current derivative assets	63	10	36	9	27	1
Current derivative liabilities	8	9	4	3	4	6
Non-current derivative liabilities	1	16	—	9	1	7

XML

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Recurring Fair Value Measurements

Carrying amounts and the related estimated fair values of other financial instruments at December 31 were as follows (in millions):

Alliant Energy	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Money market fund investments	$32	$32	$—	$—	$32	$44	$44	$—	$—	$44
Derivatives	176	—	146	30	176	34	—	5	29	34
Deferred proceeds	214	—	—	214	214	188	—	—	188	188
Liabilities and equity:
Derivatives	9	—	8	1	9	25	—	25	—	25
Long-term debt (incl. current maturities)	7,368	—	8,329	1	8,330	6,777	—	8,107	2	8,109

IPL	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Money market fund investments	$32	$32	$—	$—	$32	$44	$44	$—	$—	$44
Derivatives	84	—	65	19	84	29	—	3	26	29
Deferred proceeds	214	—	—	214	214	188	—	—	188	188
Liabilities and equity:
Derivatives	4	—	3	1	4	12	—	12	—	12
Long-term debt	3,643	—	4,124	—	4,124	3,345	—	4,021	—	4,021

WPL	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Derivatives	$92	$—	$81	$11	$92	$5	$—	$2	$3	$5
Liabilities and equity:
Derivatives	5	—	5	—	5	13	—	13	—	13
Long-term debt (incl. current maturities)	2,429	—	2,862	—	2,862	2,130	—	2,690	—	2,690

Fair Value Measurements Using Significant Unobservable Inputs

Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions):

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
	2021	2020	2021	2020
Beginning balance, January 1	$29	$21	$188	$188
Total net gains included in changes in net assets (realized/unrealized)	6	11	—	—
Purchases	21	14	—	—
Sales	(1)	(1)	—	—
Settlements (a)	(26)	(16)	26	—
Ending balance, December 31	$29	$29	$214	$188
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at December 31	$6	$11	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
	2021	2020	2021	2020
Beginning balance, January 1	$26	$18	$188	$188
Total net gains (losses) included in changes in net assets (realized/unrealized)	(3)	10	—	—
Purchases	16	11	—	—
Sales	(1)	(1)	—	—
Settlements (a)	(20)	(12)	26	—
Ending balance, December 31	$18	$26	$214	$188
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at December 31	($3)	$10	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
	2021	2020
Beginning balance, January 1	$3	$3
Total net gains included in changes in net assets (realized/unrealized)	9	1
Purchases	5	3
Settlements	(6)	(4)
Ending balance, December 31	$11	$3
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at December 31	$9	$1

(a)Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold.

Fair Value Of Net Derivative Assets (Liabilities)

The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets at December 31 as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
2021	$9	$20	$8	$10	$1	$10
2020	18	11	17	9	1	2

IPL [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Recurring Fair Value Measurements

Carrying amounts and the related estimated fair values of other financial instruments at December 31 were as follows (in millions):

Alliant Energy	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Money market fund investments	$32	$32	$—	$—	$32	$44	$44	$—	$—	$44
Derivatives	176	—	146	30	176	34	—	5	29	34
Deferred proceeds	214	—	—	214	214	188	—	—	188	188
Liabilities and equity:
Derivatives	9	—	8	1	9	25	—	25	—	25
Long-term debt (incl. current maturities)	7,368	—	8,329	1	8,330	6,777	—	8,107	2	8,109

IPL	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Money market fund investments	$32	$32	$—	$—	$32	$44	$44	$—	$—	$44
Derivatives	84	—	65	19	84	29	—	3	26	29
Deferred proceeds	214	—	—	214	214	188	—	—	188	188
Liabilities and equity:
Derivatives	4	—	3	1	4	12	—	12	—	12
Long-term debt	3,643	—	4,124	—	4,124	3,345	—	4,021	—	4,021

WPL	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Derivatives	$92	$—	$81	$11	$92	$5	$—	$2	$3	$5
Liabilities and equity:
Derivatives	5	—	5	—	5	13	—	13	—	13
Long-term debt (incl. current maturities)	2,429	—	2,862	—	2,862	2,130	—	2,690	—	2,690

Fair Value Measurements Using Significant Unobservable Inputs

Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions):

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
	2021	2020	2021	2020
Beginning balance, January 1	$29	$21	$188	$188
Total net gains included in changes in net assets (realized/unrealized)	6	11	—	—
Purchases	21	14	—	—
Sales	(1)	(1)	—	—
Settlements (a)	(26)	(16)	26	—
Ending balance, December 31	$29	$29	$214	$188
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at December 31	$6	$11	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
	2021	2020	2021	2020
Beginning balance, January 1	$26	$18	$188	$188
Total net gains (losses) included in changes in net assets (realized/unrealized)	(3)	10	—	—
Purchases	16	11	—	—
Sales	(1)	(1)	—	—
Settlements (a)	(20)	(12)	26	—
Ending balance, December 31	$18	$26	$214	$188
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at December 31	($3)	$10	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
	2021	2020
Beginning balance, January 1	$3	$3
Total net gains included in changes in net assets (realized/unrealized)	9	1
Purchases	5	3
Settlements	(6)	(4)
Ending balance, December 31	$11	$3
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at December 31	$9	$1

(a)Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold.

Fair Value Of Net Derivative Assets (Liabilities)

The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets at December 31 as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
2021	$9	$20	$8	$10	$1	$10
2020	18	11	17	9	1	2

WPL [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Recurring Fair Value Measurements

Carrying amounts and the related estimated fair values of other financial instruments at December 31 were as follows (in millions):

Alliant Energy	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Money market fund investments	$32	$32	$—	$—	$32	$44	$44	$—	$—	$44
Derivatives	176	—	146	30	176	34	—	5	29	34
Deferred proceeds	214	—	—	214	214	188	—	—	188	188
Liabilities and equity:
Derivatives	9	—	8	1	9	25	—	25	—	25
Long-term debt (incl. current maturities)	7,368	—	8,329	1	8,330	6,777	—	8,107	2	8,109

IPL	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Money market fund investments	$32	$32	$—	$—	$32	$44	$44	$—	$—	$44
Derivatives	84	—	65	19	84	29	—	3	26	29
Deferred proceeds	214	—	—	214	214	188	—	—	188	188
Liabilities and equity:
Derivatives	4	—	3	1	4	12	—	12	—	12
Long-term debt	3,643	—	4,124	—	4,124	3,345	—	4,021	—	4,021

WPL	2021					2020
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Derivatives	$92	$—	$81	$11	$92	$5	$—	$2	$3	$5
Liabilities and equity:
Derivatives	5	—	5	—	5	13	—	13	—	13
Long-term debt (incl. current maturities)	2,429	—	2,862	—	2,862	2,130	—	2,690	—	2,690

Fair Value Of Net Derivative Assets (Liabilities)

The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets at December 31 as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
2021	$9	$20	$8	$10	$1	$10
2020	18	11	17	9	1	2

XML

Commitments And Contingencies (Tables)

12 Months Ended

Dec. 31, 2021

Long-term Purchase Commitment [Line Items]

Other Purchase Commitments

At December 31, 2021, the related minimum future commitments were as follows (in millions):

Alliant Energy	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$307	$196	$144	$102	$88	$175	$1,012
Coal	63	46	25	3	—	—	137
Other (a)	82	14	8	5	2	25	136
	$452	$256	$177	$110	$90	$200	$1,285

IPL	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$148	$108	$84	$52	$42	$65	$499
Coal	32	27	17	3	—	—	79
Other (a)	34	4	2	2	2	23	67
	$214	$139	$103	$57	$44	$88	$645

WPL	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$159	$88	$60	$50	$46	$110	$513
Coal	31	19	8	—	—	—	58
Other (a)	33	1	1	1	1	—	37
	$223	$108	$69	$51	$47	$110	$608

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at December 31, 2021.

Schedule of Environmental Liabilities

At December 31, 2021, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At December 31, 2021, such amounts for WPL were not material.

	Alliant Energy			IPL
Range of estimated future costs	$8	-	$24	$6	-	$18
Current and non-current environmental liabilities	11			8

IPL [Member]

Long-term Purchase Commitment [Line Items]

Other Purchase Commitments

At December 31, 2021, the related minimum future commitments were as follows (in millions):

Alliant Energy	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$307	$196	$144	$102	$88	$175	$1,012
Coal	63	46	25	3	—	—	137
Other (a)	82	14	8	5	2	25	136
	$452	$256	$177	$110	$90	$200	$1,285

IPL	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$148	$108	$84	$52	$42	$65	$499
Coal	32	27	17	3	—	—	79
Other (a)	34	4	2	2	2	23	67
	$214	$139	$103	$57	$44	$88	$645

WPL	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$159	$88	$60	$50	$46	$110	$513
Coal	31	19	8	—	—	—	58
Other (a)	33	1	1	1	1	—	37
	$223	$108	$69	$51	$47	$110	$608

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at December 31, 2021.

Schedule of Environmental Liabilities

At December 31, 2021, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At December 31, 2021, such amounts for WPL were not material.

	Alliant Energy			IPL
Range of estimated future costs	$8	-	$24	$6	-	$18
Current and non-current environmental liabilities	11			8

WPL [Member]

Long-term Purchase Commitment [Line Items]

Other Purchase Commitments

At December 31, 2021, the related minimum future commitments were as follows (in millions):

Alliant Energy	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$307	$196	$144	$102	$88	$175	$1,012
Coal	63	46	25	3	—	—	137
Other (a)	82	14	8	5	2	25	136
	$452	$256	$177	$110	$90	$200	$1,285

IPL	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$148	$108	$84	$52	$42	$65	$499
Coal	32	27	17	3	—	—	79
Other (a)	34	4	2	2	2	23	67
	$214	$139	$103	$57	$44	$88	$645

WPL	2022	2023	2024	2025	2026	Thereafter	Total
Natural gas	$159	$88	$60	$50	$46	$110	$513
Coal	31	19	8	—	—	—	58
Other (a)	33	1	1	1	1	—	37
	$223	$108	$69	$51	$47	$110	$608

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at December 31, 2021.

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Segments Of Business (Tables)

12 Months Ended

Dec. 31, 2021

Segment Reporting Information [Line Items]

Schedule of Segments of Business

Certain financial information relating to Alliant Energy’s business segments, which represent the services provided to its customers, was as follows (in millions):

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2021	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$3,081	$456	$49	$3,586	$83	$3,669
Depreciation and amortization	591	54	6	651	6	657
Operating income (loss)	716	63	(11)	768	27	795
Interest expense				244	33	277
Equity income from unconsolidated investments, net	(2)	—	—	(2)	(60)	(62)
Income tax expense (benefit)				(87)	13	(74)
Net income attributable to Alliant Energy common shareowners				618	41	659
Total assets	14,924	1,487	1,103	17,514	1,039	18,553
Investments in equity method subsidiaries	17	—	—	17	491	508
Construction and acquisition expenditures	980	90	—	1,070	99	1,169

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2020	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$2,920	$373	$49	$3,342	$74	$3,416
Depreciation and amortization	556	49	5	610	5	615
Operating income (loss)	643	74	(1)	716	24	740
Interest expense				243	32	275
Equity income from unconsolidated investments, net	(2)	—	—	(2)	(59)	(61)
Income tax expense (benefit)				(66)	9	(57)
Net income attributable to Alliant Energy common shareowners				573	41	614
Total assets	14,358	1,413	990	16,761	949	17,710
Investments in equity method subsidiaries	11	—	—	11	465	476
Construction and acquisition expenditures	1,109	182	2	1,293	73	1,366

					ATC Holdings,
	Utility				Non-utility,	Alliant Energy
2019	Electric	Gas	Other	Total	Parent and Other	Consolidated
Revenues	$3,064	$455	$46	$3,565	$83	$3,648
Depreciation and amortization	513	47	3	563	4	567
Operating income	679	70	1	750	28	778
Interest expense				229	44	273
Equity income from unconsolidated investments, net	(1)	—	—	(1)	(52)	(53)
Income tax expense (benefit)				73	(4)	69
Net income attributable to Alliant Energy common shareowners				517	40	557
Total assets	13,659	1,269	856	15,784	917	16,701
Investments in equity method subsidiaries	9	—	—	9	449	458
Construction and acquisition expenditures	1,439	100	—	1,539	101	1,640

IPL [Member]

Segment Reporting Information [Line Items]

Schedule of Segments of Business

Certain financial information relating to IPL’s business segments, which represent the services provided to its customers, was as follows (in millions):

2021	Electric	Gas	Other	Total
Revenues	$1,752	$265	$46	$2,063
Depreciation and amortization	338	31	6	375
Operating income (loss)	420	43	(3)	460
Interest expense				139
Income tax benefit				(36)
Net income available for common stock				350
Total assets	8,602	819	575	9,996
Construction and acquisition expenditures	342	42	—	384

2020	Electric	Gas	Other	Total
Revenues	$1,695	$208	$44	$1,947
Depreciation and amortization	321	30	5	356
Operating income	358	50	2	410
Interest expense				139
Income tax benefit				(47)
Net income available for common stock				324
Total assets	8,518	766	565	9,849
Construction and acquisition expenditures	626	59	2	687

2019	Electric	Gas	Other	Total
Revenues	$1,781	$264	$44	$2,089
Depreciation and amortization	295	29	3	327
Operating income	360	39	4	403
Interest expense				127
Income taxes				24
Net income available for common stock				284
Total assets	8,075	734	468	9,277
Construction and acquisition expenditures	964	56	—	1,020

WPL [Member]

Segment Reporting Information [Line Items]

Schedule of Segments of Business

Certain financial information relating to WPL’s business segments, which represent the services provided to its customers, was as follows (in millions):

2021	Electric	Gas	Other	Total
Revenues	$1,329	$191	$3	$1,523
Depreciation and amortization	253	23	—	276
Operating income (loss)	296	20	(8)	308
Interest expense				105
Income tax benefit				(51)
Net income				268
Total assets	6,322	668	528	7,518
Construction and acquisition expenditures	638	48	—	686

2020	Electric	Gas	Other	Total
Revenues	$1,225	$165	$5	$1,395
Depreciation and amortization	235	19	—	254
Operating income (loss)	285	24	(3)	306
Interest expense				104
Income tax benefit				(19)
Net income				249
Total assets	5,840	647	425	6,912
Construction and acquisition expenditures	483	123	—	606

2019	Electric	Gas	Other	Total
Revenues	$1,283	$191	$2	$1,476
Depreciation and amortization	218	18	—	236
Operating income (loss)	319	31	(3)	347
Interest expense				102
Income taxes				49
Net income				233
Total assets	5,584	535	388	6,507
Construction and acquisition expenditures	475	44	—	519

XML

Related Parties (Tables)

12 Months Ended

Dec. 31, 2021

Related Party Transaction [Line Items]

Services Provided, Sales Credited And Purchases Billed

The amounts billed for services provided, sales credited and purchases were as follows (in millions):

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Corporate Services billings	$180	$176	$185	$154	$142	$142
Sales credited	22	35	68	23	3	7
Purchases billed	441	329	331	116	108	120

Net Intercompany Payables

As of December 31, net intercompany payables to Corporate Services were as follows (in millions):

	2021	2020
IPL	$110	$110
WPL	83	73

Related Amounts Billed Between Parties

The related amounts billed between the parties were as follows (in millions):

	2021	2020	2019
ATC billings to WPL	$122	$108	$109
WPL billings to ATC	18	10	13

IPL [Member]

Related Party Transaction [Line Items]

Services Provided, Sales Credited And Purchases Billed

The amounts billed for services provided, sales credited and purchases were as follows (in millions):

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Corporate Services billings	$180	$176	$185	$154	$142	$142
Sales credited	22	35	68	23	3	7
Purchases billed	441	329	331	116	108	120

Net Intercompany Payables

As of December 31, net intercompany payables to Corporate Services were as follows (in millions):

	2021	2020
IPL	$110	$110
WPL	83	73

WPL [Member]

Related Party Transaction [Line Items]

Services Provided, Sales Credited And Purchases Billed

The amounts billed for services provided, sales credited and purchases were as follows (in millions):

	IPL			WPL
	2021	2020	2019	2021	2020	2019
Corporate Services billings	$180	$176	$185	$154	$142	$142
Sales credited	22	35	68	23	3	7
Purchases billed	441	329	331	116	108	120

Net Intercompany Payables

As of December 31, net intercompany payables to Corporate Services were as follows (in millions):

	2021	2020
IPL	$110	$110
WPL	83	73

Related Amounts Billed Between Parties

The related amounts billed between the parties were as follows (in millions):

	2021	2020	2019
ATC billings to WPL	$122	$108	$109
WPL billings to ATC	18	10	13

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Condensed Parent Company Financial Statements (Tables)

12 Months Ended

Dec. 31, 2021

Condensed Financial Information Disclosure [Abstract]

Condensed Statements of Income

ALLIANT ENERGY CORPORATION (Parent Company Only)	Year Ended December 31,
CONDENSED STATEMENTS OF INCOME	2021	2020	2019
	(in millions)
Operating expenses	$5	$7	$2
Operating loss	(5)	(7)	(2)
Other (income) and deductions:
Equity earnings from consolidated subsidiaries	(664)	(625)	(562)
Interest expense	1	2	9
Other	1	4	7
Total other (income) and deductions	(662)	(619)	(546)
Income before income taxes	657	612	544
Income tax benefit	(5)	(4)	(15)
Net income	$662	$616	$559

Refer to accompanying Notes to Condensed Financial Statements.

Condensed Balance Sheets

ALLIANT ENERGY CORPORATION (Parent Company Only)	December 31,
CONDENSED BALANCE SHEETS	2021	2020
	(in millions)
ASSETS
Current assets:
Notes receivable from affiliated companies	$16	$32
Other	5	5
Total current assets	21	37
Investments:
Investments in consolidated subsidiaries	7,061	6,664
Other	2	2
Total investments	7,063	6,666
Other assets	96	88
Total assets	$7,180	$6,791

LIABILITIES AND EQUITY
Current liabilities:
Commercial paper	$279	$132
Notes payable to affiliated companies	900	937
Other	4	29
Total current liabilities	1,183	1,098
Other liabilities	2	2
Common equity:
Common stock and additional paid-in capital	2,752	2,706
Retained earnings	3,255	2,996
Shares in deferred compensation trust	(12)	(11)
Total common equity	5,995	5,691
Total liabilities and equity	$7,180	$6,791

Refer to accompanying Notes to Condensed Financial Statements.

Condensed Statements of Cash Flows

ALLIANT ENERGY CORPORATION (Parent Company Only)	Year Ended December 31,
CONDENSED STATEMENTS OF CASH FLOWS	2021	2020	2019
	(in millions)
Net cash flows from operating activities	$494	$396	$305
Cash flows used for investing activities:
Capital contributions to consolidated subsidiaries	(295)	(429)	(250)
Net change in notes receivable from and payable to affiliates	(21)	201	8
Dividends from consolidated subsidiaries in excess of equity earnings	50	—	—
Net cash flows used for investing activities	(266)	(228)	(242)
Cash flows used for financing activities:
Common stock dividends	(403)	(377)	(338)
Proceeds from issuance of common stock, net	28	247	390
Net change in commercial paper	147	(37)	(116)
Other	—	(1)	1
Net cash flows used for financing activities	(228)	(168)	(63)
Net increase (decrease) in cash, cash equivalents and restricted cash	—	—	—
Cash, cash equivalents and restricted cash at beginning of period	—	—	—
Cash, cash equivalents and restricted cash at end of period	$—	$—	$—
Supplemental cash flows information:
Cash (paid) refunded during the period for:
Interest	($1)	($2)	($9)
Income taxes, net	4	10	14

Refer to accompanying Notes to Condensed Financial Statements.

XML

Summary Of Significant Accounting Policies (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) customer MW	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Cash, Cash Equivalents and Restricted Cash [Abstract]
Money market fund investments	$ 32	$ 44
Money market fund investments interest rate, percentage	0.04%
Current and Expected Credit Loss Estimates:
Adoption of new accounting standard, net of tax	$ (3,250)	(2,994)
Cumulative Effect, Period of Adoption, Adjustment [Member]
Current and Expected Credit Loss Estimates:
New accounting standard, cumulative effect adjustment to retained earnings, pre-tax			$ 12
Adoption of new accounting standard, net of tax			$ 9
IPL [Member]
General:
Generation and distribution of steam, number of customers served (in customers) | customer	2
Electric capacity of wind farm (in megawatts) | MW	1,000
Cash, Cash Equivalents and Restricted Cash [Abstract]
Money market fund investments	$ 32	44
Money market fund investments interest rate, percentage	0.04%
Property, Plant and Equipment:
AFUDC accrual recorded, percentage of estimated CWIP	100.00%
Current and Expected Credit Loss Estimates:
Adoption of new accounting standard, net of tax	$ (929)	(979)
WPL [Member]
Property, Plant and Equipment:
AFUDC accrual recorded, percentage of estimated CWIP	50.00%
AFUDC rates, projects with approval	100.00%
Current and Expected Credit Loss Estimates:
Adoption of new accounting standard, net of tax	$ (1,053)	$ (953)
Alliant Energy Finance, LLC [Member]
General:
Ownership interest	50.00%
Electric capacity of wind farm (in megawatts) | MW	225
Sheboygan Falls Energy Facility [Member]
General:
Fossil-fueled EGU capacity (in megawatts) | MW	347
Finance lease, lease term	20 years

XML

Summary Of Significant Accounting Policies (Schedule Of Average Rates Of Depreciation) (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Electric - generation [Member] | IPL [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Average rate of depreciation	3.40%	3.50%	3.80%
Electric - generation [Member] | WPL [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Average rate of depreciation	3.50%	3.50%	3.60%
Electric - distribution [Member] | IPL [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Average rate of depreciation	2.90%	2.80%	2.90%
Electric - distribution [Member] | WPL [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Average rate of depreciation	2.60%	2.60%	2.60%
Electric - other [Member] | IPL [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Average rate of depreciation	5.70%	5.20%	5.30%
Electric - other [Member] | WPL [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Average rate of depreciation	7.40%	6.10%	5.80%
Gas [Member] | IPL [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Average rate of depreciation	3.30%	3.30%	3.30%
Gas [Member] | WPL [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Average rate of depreciation	2.40%	2.40%	2.50%
Other [Member] | IPL [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Average rate of depreciation	6.10%	6.30%	5.90%
Other [Member] | WPL [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Average rate of depreciation	5.40%	5.90%	5.60%

XML

Summary Of Significant Accounting Policies (Schedule Of Allowance For Funds Used During Construction Recovery Rate) (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
IPL [Member] | IPL (Wind generation CWIP) [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Recovery rates	7.00%	7.10%	7.40%
IPL [Member] | IPL (other CWIP) [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Recovery rates	7.20%	7.20%	7.50%
WPL [Member] | WPL (retail jurisdiction) [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Recovery rates	7.00%	7.00%	6.80%
WPL [Member] | WPL (wholesale jurisdiction) [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Recovery rates	5.60%	6.30%	6.90%

XML

Regulatory Matters (Narrative) (Details) $ in Millions	1 Months Ended		12 Months Ended
	Sep. 30, 2020 USD ($)	Aug. 31, 2020 customer	Dec. 31, 2021 USD ($) MW	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Regulatory Matters [Line Items]
Regulatory assets			$ 1,940	$ 2,010
Credits issued to customers			(66)	(113)	$ (40)
Regulatory liabilities			1,271	1,306
Electric transmission cost recovery [Member]
Regulatory Matters [Line Items]
Regulatory liabilities			51	68
IPL [Member]
Regulatory Matters [Line Items]
Regulatory assets not earning a return			75
Regulatory assets			1,443	1,483
Credits issued to customers			$ 1	(20)	2
Electric capacity of wind farm (in megawatts) | MW			1,000
Regulatory liabilities			$ 691	676
IPL [Member] | Electric transmission cost recovery [Member]
Regulatory Matters [Line Items]
Credits issued to customers				42
Regulatory liabilities			27	39
IPL [Member] | Derecho windstorm [Member]
Regulatory Matters [Line Items]
Number of customers without power, derecho windstorm (number of customers) | customer		250,000
Derecho windstorm repair and rebuilding costs			140
Net regulatory liability, derecho windstorm			8
WPL [Member]
Regulatory Matters [Line Items]
Regulatory assets not earning a return			13
Regulatory assets			497	527
Credits issued to customers			(67)	(93)	(42)
Regulatory liabilities			580	630
WPL [Member] | Electric transmission cost recovery [Member]
Regulatory Matters [Line Items]
Regulatory liabilities			24	29
2020 Test Period Retail Electric [Member] | IPL [Member]
Regulatory Matters [Line Items]
Interim rate increase (decrease), amount					$ 90
Authorized increase (decrease) in final rates, amount				127
2020 Test Period Retail Electric [Member] | IPL [Member] | Tax-related [Member]
Regulatory Matters [Line Items]
Regulatory liabilities				27
2020 Test Period Retail Electric [Member] | IPL [Member] | Revenue subject to refund [Member]
Regulatory Matters [Line Items]
Regulatory liabilities				8
2020 Test Period Retail Electric [Member] | WPL [Member]
Regulatory Matters [Line Items]
Authorized increase (decrease) in final rates, amount				$ 29
Authorized increase (decrease) in final rates, percentage				2.00%
2020 Test Period Retail Gas [Member] | IPL [Member]
Regulatory Matters [Line Items]
Authorized increase (decrease) in final rates, amount				$ 12
2019 Test Period Retail Electric [Member] | WPL [Member] | Revenue subject to refund [Member]
Regulatory Matters [Line Items]
Credits issued to customers				$ 12
Deferred Fuel Costs | WPL [Member]
Regulatory Matters [Line Items]
Regulatory assets			$ 37
DAEC PPA [Member]
Regulatory Matters [Line Items]
Buyout payment	$ 110
PPA term amendment			5 years

XML

Regulatory Matters (Regulatory Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Regulatory Assets [Line Items]
Regulatory assets	$ 1,940	$ 2,010
Tax-related [Member]
Regulatory Assets [Line Items]
Regulatory assets	934	890
Pension and OPEB costs [Member]
Regulatory Assets [Line Items]
Regulatory assets	462	580
AROs [Member]
Regulatory Assets [Line Items]
Regulatory assets	128	119
Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	92	113
IPL's DAEC PPA amendment [Member]
Regulatory Assets [Line Items]
Regulatory assets	90	110
WPL's Western Wisconsin gas distribution expansion investments [Member]
Regulatory Assets [Line Items]
Regulatory assets	52	55
Commodity cost recovery [Member]
Regulatory Assets [Line Items]
Regulatory assets	42	4
Derivatives [Member]
Regulatory Assets [Line Items]
Regulatory assets	8	26
Other [Member]
Regulatory Assets [Line Items]
Regulatory assets	132	113
IPL [Member]
Regulatory Assets [Line Items]
Regulatory assets	1,443	1,483
IPL [Member] | Tax-related [Member]
Regulatory Assets [Line Items]
Regulatory assets	884	843
IPL [Member] | Pension and OPEB costs [Member]
Regulatory Assets [Line Items]
Regulatory assets	228	291
IPL [Member] | AROs [Member]
Regulatory Assets [Line Items]
Regulatory assets	89	81
IPL [Member] | Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	66	77
IPL [Member] | IPL's DAEC PPA amendment [Member]
Regulatory Assets [Line Items]
Regulatory assets	90	110
IPL [Member] | Commodity cost recovery [Member]
Regulatory Assets [Line Items]
Regulatory assets	2	1
IPL [Member] | Derivatives [Member]
Regulatory Assets [Line Items]
Regulatory assets	4	13
IPL [Member] | Other [Member]
Regulatory Assets [Line Items]
Regulatory assets	80	67
WPL [Member]
Regulatory Assets [Line Items]
Regulatory assets	497	527
WPL [Member] | Tax-related [Member]
Regulatory Assets [Line Items]
Regulatory assets	50	47
WPL [Member] | Pension and OPEB costs [Member]
Regulatory Assets [Line Items]
Regulatory assets	234	289
WPL [Member] | AROs [Member]
Regulatory Assets [Line Items]
Regulatory assets	39	38
WPL [Member] | Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	26	36
WPL [Member] | WPL's Western Wisconsin gas distribution expansion investments [Member]
Regulatory Assets [Line Items]
Regulatory assets	52	55
WPL [Member] | Commodity cost recovery [Member]
Regulatory Assets [Line Items]
Regulatory assets	40	3
WPL [Member] | Derivatives [Member]
Regulatory Assets [Line Items]
Regulatory assets	4	13
WPL [Member] | Other [Member]
Regulatory Assets [Line Items]
Regulatory assets	$ 52	$ 46

XML

Regulatory Matters (Assets Retired Early) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Regulatory Assets [Line Items]
Regulatory assets	$ 1,940	$ 2,010
Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	92	113
IPL [Member]
Regulatory Assets [Line Items]
Regulatory assets	1,443	1,483
IPL [Member] | Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	66	77
IPL [Member] | Assets retired early [Member] | Sutherland Units 1 and 3 [Member]
Regulatory Assets [Line Items]
Regulatory assets	19
IPL [Member] | Assets retired early [Member] | M.L. Kapp Unit 2 [Member]
Regulatory Assets [Line Items]
Regulatory assets	18
IPL [Member] | Assets retired early [Member] | Analog Electric Meters [Member]
Regulatory Assets [Line Items]
Regulatory assets	29
WPL [Member]
Regulatory Assets [Line Items]
Regulatory assets	497	527
WPL [Member] | Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	26	$ 36
WPL [Member] | Assets retired early [Member] | Nelson Dewey Units 1 and 2 and Edgewater Unit 3 [Member]
Regulatory Assets [Line Items]
Regulatory assets	6
WPL [Member] | Assets retired early [Member] | Edgewater Unit 4 [Member]
Regulatory Assets [Line Items]
Regulatory assets	$ 20

XML

Regulatory Matters (Regulatory Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Regulatory Liabilities [Line Items]
Regulatory liabilities	$ 1,271	$ 1,306
Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	585	732
Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	384	367
Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	166	28
Electric transmission cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	51	68
WPL's West Riverside liquidated damages [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	36	38
Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	49	73
IPL [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	691	676
IPL [Member] | Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	312	331
IPL [Member] | Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	252	238
IPL [Member] | Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	77	25
IPL [Member] | Electric transmission cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	27	39
IPL [Member] | Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	23	43
WPL [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	580	630
WPL [Member] | Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	273	401
WPL [Member] | Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	132	129
WPL [Member] | Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	89	3
WPL [Member] | Electric transmission cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	24	29
WPL [Member] | WPL's West Riverside liquidated damages [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	36	38
WPL [Member] | Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	$ 26	$ 30

XML

Property, Plant and Equipment (Narrative) (Details)	12 Months Ended
	Dec. 31, 2021
Corporate Services [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Corporate Services [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	30 years
Sheboygan Falls Energy Facility [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	35 years
Customer Billing And Information System [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	12 years
Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years

XML

Property, Plant and Equipment (Property, Plant and Equipment) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	$ 2,094	$ 1,269
Total electric plant	16,710	16,243
Gas plant in service	1,636	1,563
Other plant in service	621	534
Accumulated depreciation	(5,263)	(4,868)
Net plant	13,704	13,472
Leased land for solar generation, net	11	0
Construction work in progress	778	405
Other, net	7	7
Total utility	14,500	13,884
Non-utility Generation, net	75	79
Corporate Services and other, net	412	373
Total non-utility and other	487	452
Total property, plant and equipment	14,987	14,336
Non-utility Generation, accumulated depreciation	67	63
Corporate Services and other, accumulated depreciation	245	210
Generation [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	7,539	8,222
Distribution [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	6,537	6,216
Other [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	540	536
IPL [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	487	459
Total electric plant	9,424	9,171
Gas plant in service	878	844
Other plant in service	398	354
Accumulated depreciation	(2,897)	(2,671)
Net plant	7,803	7,698
Construction work in progress	174	185
Other, net	6	6
Total utility	7,983	7,889
Total property, plant and equipment	7,983	7,889
IPL [Member] | Lansing [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	245
IPL [Member] | Generation [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	4,922	4,884
IPL [Member] | Distribution [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	3,652	3,470
IPL [Member] | Other [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	363	358
WPL [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	1,607	810
Total electric plant	7,286	7,072
Gas plant in service	758	719
Other plant in service	223	180
Accumulated depreciation	(2,366)	(2,197)
Net plant	5,901	5,774
Leased Sheboygan Falls Energy Facility, net	21	27
Leased land for solar generation, net	11	0
Construction work in progress	604	220
Other, net	1	1
Total utility	6,538	6,022
Total property, plant and equipment	6,538	6,022
Leased Sheboygan Falls Energy Facility, accumulated depreciation	100	95
WPL [Member] | Edgewater Unit 5 [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	527
WPL [Member] | Columbia Units 1 And 2 [Member]
Property, Plant and Equipment [Line Items]
Electric plant anticipated to be retired early	460
WPL [Member] | Generation [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	2,617	3,338
WPL [Member] | Distribution [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	2,885	2,746
WPL [Member] | Other [Member]
Property, Plant and Equipment [Line Items]
Electric plant in service	$ 177	$ 178

XML

Property, Plant and Equipment (Equity and Debt AFUDC) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Allowance for funds used during construction	$ 25	$ 55	$ 93
Equity [Member]
Property, Plant and Equipment [Line Items]
Allowance for funds used during construction	18	39	66
Debt [Member]
Property, Plant and Equipment [Line Items]
Allowance for funds used during construction	7	16	27
IPL [Member]
Property, Plant and Equipment [Line Items]
Allowance for funds used during construction	9	24	50
IPL [Member] | Equity [Member]
Property, Plant and Equipment [Line Items]
Allowance for funds used during construction	7	17	35
IPL [Member] | Debt [Member]
Property, Plant and Equipment [Line Items]
Allowance for funds used during construction	2	7	15
WPL [Member]
Property, Plant and Equipment [Line Items]
Allowance for funds used during construction	16	31	43
WPL [Member] | Equity [Member]
Property, Plant and Equipment [Line Items]
Allowance for funds used during construction	11	22	31
WPL [Member] | Debt [Member]
Property, Plant and Equipment [Line Items]
Allowance for funds used during construction	$ 5	$ 9	$ 12

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Jointly-Owned Electric Utility Plant (Details) $ in Millions	Dec. 31, 2021 USD ($)
Jointly Owned Electric Utility Plant [Line Items]
Electric Plant	$ 2,631
Accumulated Provision for Depreciation	806
Construction Work in Progress	25
IPL [Member]
Jointly Owned Electric Utility Plant [Line Items]
Electric Plant	1,005
Accumulated Provision for Depreciation	411
Construction Work in Progress	16
WPL [Member]
Jointly Owned Electric Utility Plant [Line Items]
Electric Plant	1,626
Accumulated Provision for Depreciation	395
Construction Work in Progress	$ 9
Ottumwa Unit 1 [Member] | IPL [Member]
Jointly Owned Electric Utility Plant [Line Items]
Ownership Interest %	48.00%
Electric Plant	$ 599
Accumulated Provision for Depreciation	214
Construction Work in Progress	$ 11
George Neal Unit 4 [Member] | IPL [Member]
Jointly Owned Electric Utility Plant [Line Items]
Ownership Interest %	25.70%
Electric Plant	$ 193
Accumulated Provision for Depreciation	100
Construction Work in Progress	$ 2
George Neal Unit 3 [Member] | IPL [Member]
Jointly Owned Electric Utility Plant [Line Items]
Ownership Interest %	28.00%
Electric Plant	$ 173
Accumulated Provision for Depreciation	74
Construction Work in Progress	$ 3
Louisa Unit 1 [Member] | IPL [Member]
Jointly Owned Electric Utility Plant [Line Items]
Ownership Interest %	4.00%
Electric Plant	$ 40
Accumulated Provision for Depreciation	23
Construction Work in Progress	$ 0
Columbia Units 1-2 [Member] | WPL [Member]
Jointly Owned Electric Utility Plant [Line Items]
Ownership Interest %	53.50%
Electric Plant	$ 802
Accumulated Provision for Depreciation	314
Construction Work in Progress	$ 6
West Riverside Energy Center and Solar Garden [Member] | WPL [Member]
Jointly Owned Electric Utility Plant [Line Items]
Ownership Interest %	91.00%
Electric Plant	$ 706
Accumulated Provision for Depreciation	33
Construction Work in Progress	$ 3
Forward Wind Energy Center [Member] | WPL [Member]
Jointly Owned Electric Utility Plant [Line Items]
Ownership Interest %	42.60%
Electric Plant	$ 118
Accumulated Provision for Depreciation	48
Construction Work in Progress	$ 0

XML

Receivables (Narrative) (Details) $ in Millions	Dec. 31, 2021 USD ($)
Maximum [Member]
Accounts Receivable [Line Items]
Limit on cash proceeds to be received from third-party	$ 110
Financing Receivable [Member] | IPL [Member]
Accounts Receivable [Line Items]
Available capacity	$ 109

XML

Receivables (Details of Accounts Receivable) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Accounts Receivable [Line Items]
Customer	$ 93	$ 101
Unbilled utility revenues	91	82
Deferred proceeds	214	188
Other	53	59
Allowance for expected credit losses	(11)	(18)
Accounts receivable, less allowance for expected credit losses	440	412
IPL [Member]
Accounts Receivable [Line Items]
Customer	0	0
Unbilled utility revenues	0	0
Deferred proceeds	214	188
Other	28	23
Allowance for expected credit losses	(1)	(1)
Accounts receivable, less allowance for expected credit losses	241	210
WPL [Member]
Accounts Receivable [Line Items]
Customer	82	92
Unbilled utility revenues	91	82
Other	25	35
Allowance for expected credit losses	(10)	(17)
Accounts receivable, less allowance for expected credit losses	$ 188	$ 192

XML

Receivables (Maximum And Average Outstanding Cash Proceeds) (Details) - IPL [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Maximum [Member]
Accounts Receivable [Line Items]
Outstanding aggregate cash proceeds (based on daily outstanding balances)	$ 110	$ 96	$ 108
Average [Member]
Accounts Receivable [Line Items]
Outstanding aggregate cash proceeds (based on daily outstanding balances)	$ 46	$ 9	$ 36

XML

Receivables (Receivables Sold Under The Agreement) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Accounts Receivable [Line Items]
Fair value of deferred proceeds	$ 214	$ 188
IPL [Member]
Accounts Receivable [Line Items]
Fair value of deferred proceeds	214	188
Financing Receivable [Member] | IPL [Member]
Accounts Receivable [Line Items]
Customer accounts receivable	125	114
Unbilled utility revenues	104	92
Receivables sold to third party	229	206
Less: cash proceeds	1	1
Deferred proceeds	228	205
Less: allowance for expected credit losses	14	17
Fair value of deferred proceeds	214	188
Financing Receivable [Member] | IPL [Member] | Financial Asset, Past Due
Accounts Receivable [Line Items]
Outstanding receivables past due	$ 22	$ 27

XML

Receivables (Additional Attributes Of Receivables Sold Under The Agreement) (Details) - IPL [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts Receivable [Line Items]
Collections	$ 2,134	$ 2,025	$ 2,193
Write-offs, net of recoveries	$ 9	$ 7	$ 19

XML

Investments (Narrative) (Details)	Dec. 31, 2021
ATC LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest	16.00%
ATC Holdco LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest	20.00%

XML

Investments (Unconsolidated Equity Investments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Carrying value	$ 508	$ 476	$ 458
Equity (income) / loss	(62)	(61)	(53)
ATC Holdings [Member]
Schedule of Equity Method Investments [Line Items]
Carrying value	338	331
Equity (income) / loss	$ (43)	(47)	(45)
ATC LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest	16.00%
ATC Holdco LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest	20.00%
Non-utility wind farm in Oklahoma [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest	50.00%
Carrying value	$ 99	103
Equity (income) / loss	(4)	(8)	(5)
Corporate venture investments [Member]
Schedule of Equity Method Investments [Line Items]
Carrying value	52	31
Equity (income) / loss	(13)	(4)	(1)
Other [Member]
Schedule of Equity Method Investments [Line Items]
Carrying value	19	11
Equity (income) / loss	(2)	(2)	(2)
Total [Member]
Schedule of Equity Method Investments [Line Items]
Carrying value	508	476
Equity (income) / loss	$ (62)	$ (61)	$ (53)

XML

Investments (Summary Financial Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues	$ 3,669	$ 3,416	$ 3,648
Current assets	1,069	887
Current liabilities	2,054	1,297
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]
Revenues	802	801	783
Operating income	357	376	359
Net income	358	343	$ 340
Current assets	112	121
Non-current assets	7,036	6,388
Current liabilities	455	317
Non-current liabilities	3,110	2,997
Noncontrolling interest	$ 247	$ 192

XML

Common Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Common Equity [Line Items]
Shares available for issuance under the 2020 OIP, Shareowner Direct Plan and 401(k) Savings Plan (in shares)	14,000,000
Proceeds from issuance of common stock, net	$ 28	$ 247	$ 390
Equity Forward Agreements [Member]
Schedule of Common Equity [Line Items]
Common stock issued during the period (in shares)	0	4,275,127	8,358,973
Proceeds from issuance of common stock, net		$ 222	$ 366
Initial forward sale price (in dollars per share)		$ 51.98	$ 43.75

XML

Common Equity (Common Share Activity) (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Common Stock Oustanding [Roll Forward]
Shares outstanding, January 1 (in shares)	249,868,415	245,022,800	236,063,279
Common stock issued during the period, Shareowner Direct Plan (in shares)	492,565	472,283	501,808
Common stock issued during the period, Equity-based compensation plans (in shares)	113,549	98,205	101,478
Common stock issued during the period, Other (in shares)	0	0	(2,738)
Shares outstanding, December 31 (in shares)	250,474,529	249,868,415	245,022,800
Equity Forward Agreements [Member]
Common Stock Oustanding [Roll Forward]
Common stock issued during the period (in shares)	0	4,275,127	8,358,973

XML

Preferred Stock (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Temporary Equity [Line Items]
Payments to redeem cumulative preferred stock of IPL	$ 200	$ 0	$ 0
Cumulative Preferred Stock [Member] | 5.1% [Member]
Temporary Equity [Line Items]
Non-cash charge, preferred stock redemption	5
IPL [Member]
Temporary Equity [Line Items]
Payments to redeem cumulative preferred stock of IPL	$ 200	$ 0	$ 0
IPL [Member] | Cumulative Preferred Stock [Member]
Temporary Equity [Line Items]
Shares authorized (in shares)	16,000,000
IPL [Member] | Cumulative Preferred Stock [Member] | 5.1% [Member]
Temporary Equity [Line Items]
Shares authorized (in shares)		8,000,000
Shares outstanding (in shares)		8,000,000
Cumulative preferred stock rate		5.10%
Preferred stock redemption price per share (in dollars per share)		$ 25
Payments to redeem cumulative preferred stock of IPL	$ 200
Non-cash charge, preferred stock redemption	$ 5

XML

Preferred Stock (Carrying Value Of Cumulative Preferred Stock) (Details) - IPL [Member] - Cumulative Preferred Stock [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021
Temporary Equity [Line Items]
Shares Authorized (in shares)		16,000,000
5.1% [Member]
Temporary Equity [Line Items]
Series	5.10%
Liquidation Preference/Stated Value (in dollars per share)	$ 25
Shares Authorized (in shares)	8,000,000
Preferred Stock, Shares Outstanding	8,000,000
Cumulative preferred stock	$ 200

XML

Debt (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Line of credit facility, current borrowing capacity		$ 1,000
Parent Company [Member]
Debt Instrument [Line Items]
Line of credit facility, current borrowing capacity		450
IPL [Member]
Debt Instrument [Line Items]
Line of credit facility, current borrowing capacity		250
WPL [Member]
Debt Instrument [Line Items]
Line of credit facility, current borrowing capacity		$ 300
Forecast [Member] | Parent Company [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 500
Forecast [Member] | IPL [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	400
Forecast [Member] | WPL [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 500

XML

Debt (Credit Facilities) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Commercial paper and borrowings under the single credit facility:
Amount outstanding	$ 515	$ 389
Weighted average interest rates	0.20%	0.20%
Available credit facility capacity	$ 485	$ 611
IPL [Member]
Commercial paper and borrowings under the single credit facility:
Amount outstanding	0	0
Available credit facility capacity	250	250
WPL [Member]
Commercial paper and borrowings under the single credit facility:
Amount outstanding	$ 236	$ 257
Weighted average interest rates	0.20%	0.10%
Available credit facility capacity	$ 64	$ 43

XML

Debt (Other Short-Term Borrowings) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Maximum amount outstanding (based on daily outstanding balances)	$ 648	$ 495
Average amount outstanding (based on daily outstanding balances)	$ 459	$ 292
Weighted average interest rates	0.20%	0.70%
IPL [Member]
Debt Instrument [Line Items]
Maximum amount outstanding (based on daily outstanding balances)	$ 19	$ 8
Average amount outstanding (based on daily outstanding balances)	$ 0	$ 0
Weighted average interest rates	0.20%	0.50%
WPL [Member]
Debt Instrument [Line Items]
Maximum amount outstanding (based on daily outstanding balances)	$ 320	$ 266
Average amount outstanding (based on daily outstanding balances)	$ 172	$ 117
Weighted average interest rates	0.10%	0.70%

XML

Debt (Long-term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Long-term debt	$ 7,425	$ 6,833
Current maturities	(633)	(8)
Unamortized debt issuance costs	(42)	(41)
Unamortized debt (discount) and premium, net	(15)	(15)
Long-term debt, net	6,735	6,769
Senior Debentures [Member]
Debt Instrument [Line Items]
Long-term debt	3,675	3,375
Senior Debentures [Member] | 3.25% senior debenture, due 2024 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 500	$ 500
Interest rate	3.25%	3.25%
Senior Debentures [Member] | 3.4% senior debenture, due 2025 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 250	$ 250
Interest rate	3.40%	3.40%
Senior Debentures [Member] | 5.5% senior debenture, due 2025 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 50	$ 50
Interest rate	5.50%	5.50%
Senior Debentures [Member] | 4.1% senior debenture, due 2028 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 500	$ 500
Interest rate	4.10%	4.10%
Senior Debentures [Member] | 3.6% senior debenture, due 2029 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300	$ 300
Interest rate	3.60%	3.60%
Senior Debentures [Member] | 2.3% senior debenture, due 2030 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 400	$ 400
Interest rate	2.30%	2.30%
Senior Debentures [Member] | 6.45% senior debenture, due 2033 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 100	$ 100
Interest rate	6.45%	6.45%
Senior Debentures [Member] | 6.3% senior debenture, due 2034 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 125	$ 125
Interest rate	6.30%	6.30%
Senior Debentures [Member] | 6.25% senior debenture, due 2039 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300	$ 300
Interest rate	6.25%	6.25%
Senior Debentures [Member] | 4.7% senior debenture, due 2043 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 250	$ 250
Interest rate	4.70%	4.70%
Senior Debentures [Member] | 3.7% senior debenture, due 2046 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300	$ 300
Interest rate	3.70%	3.70%
Senior Debentures [Member] | 3.5% senior debenture, due 2049 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300	$ 300
Interest rate	3.50%	3.50%
Senior Debentures [Member] | 3.1% senior debenture, due 2051 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300
Interest rate	3.10%
Debentures [Member]
Debt Instrument [Line Items]
Long-term debt	$ 2,450	$ 2,150
Debentures [Member] | 2.25% debenture, due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 250	$ 250
Interest rate	2.25%	2.25%
Debentures [Member] | 3.05% debenture, due 2027 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300	$ 300
Interest rate	3.05%	3.05%
Debentures [Member] | 3% debenture, due 2029 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 350	$ 350
Interest rate	3.00%	3.00%
Debentures [Member] | 1.95% debenture, due 2031 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300
Interest rate	1.95%
Debentures [Member] | 6.25% debenture, due 2034 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 100	$ 100
Interest rate	6.25%	6.25%
Debentures [Member] | 6.375% debenture, due 2037 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300	$ 300
Interest rate	6.375%	6.375%
Debentures [Member] | 7.6% debenture, due 2038 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 250	$ 250
Interest rate	7.60%	7.60%
Debentures [Member] | 4.1% debenture, due 2044 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 250	$ 250
Interest rate	4.10%	4.10%
Debentures [Member] | 3.65% debenture, due 2050 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 350	$ 350
Interest rate	3.65%	3.65%
Other Long Term Debt [Member]
Debt Instrument [Line Items]
Long-term debt	$ 1,300	$ 1,308
Other [Member] | Other, 1% at December 31, 2021, due 2022 to 2025 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 1	2
Interest rate	1.00%
IPL [Member]
Debt Instrument [Line Items]
Long-term debt	$ 3,675	3,375
Current maturities	0	0
Unamortized debt issuance costs	(23)	(22)
Unamortized debt (discount) and premium, net	(9)	(8)
Long-term debt, net	3,643	3,345
IPL [Member] | Senior Debentures [Member]
Debt Instrument [Line Items]
Long-term debt	3,675	3,375
IPL [Member] | Senior Debentures [Member] | 3.25% senior debenture, due 2024 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 500	$ 500
Interest rate	3.25%	3.25%
IPL [Member] | Senior Debentures [Member] | 3.4% senior debenture, due 2025 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 250	$ 250
Interest rate	3.40%	3.40%
IPL [Member] | Senior Debentures [Member] | 5.5% senior debenture, due 2025 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 50	$ 50
Interest rate	5.50%	5.50%
IPL [Member] | Senior Debentures [Member] | 4.1% senior debenture, due 2028 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 500	$ 500
Interest rate	4.10%	4.10%
IPL [Member] | Senior Debentures [Member] | 3.6% senior debenture, due 2029 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300	$ 300
Interest rate	3.60%	3.60%
IPL [Member] | Senior Debentures [Member] | 2.3% senior debenture, due 2030 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 400	$ 400
Interest rate	2.30%	2.30%
IPL [Member] | Senior Debentures [Member] | 6.45% senior debenture, due 2033 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 100	$ 100
Interest rate	6.45%	6.45%
IPL [Member] | Senior Debentures [Member] | 6.3% senior debenture, due 2034 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 125	$ 125
Interest rate	6.30%	6.30%
IPL [Member] | Senior Debentures [Member] | 6.25% senior debenture, due 2039 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300	$ 300
Interest rate	6.25%	6.25%
IPL [Member] | Senior Debentures [Member] | 4.7% senior debenture, due 2043 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 250	$ 250
Interest rate	4.70%	4.70%
IPL [Member] | Senior Debentures [Member] | 3.7% senior debenture, due 2046 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300	$ 300
Interest rate	3.70%	3.70%
IPL [Member] | Senior Debentures [Member] | 3.5% senior debenture, due 2049 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300	$ 300
Interest rate	3.50%	3.50%
IPL [Member] | Senior Debentures [Member] | 3.1% senior debenture, due 2051 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300
Interest rate	3.10%
WPL [Member]
Debt Instrument [Line Items]
Long-term debt	$ 2,450	$ 2,150
Current maturities	(250)	0
Unamortized debt issuance costs	(15)	(14)
Unamortized debt (discount) and premium, net	(6)	(6)
Long-term debt, net	2,179	2,130
WPL [Member] | Debentures [Member]
Debt Instrument [Line Items]
Long-term debt	2,450	2,150
WPL [Member] | Debentures [Member] | 2.25% debenture, due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 250	$ 250
Interest rate	2.25%	2.25%
WPL [Member] | Debentures [Member] | 3.05% debenture, due 2027 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300	$ 300
Interest rate	3.05%	3.05%
WPL [Member] | Debentures [Member] | 3% debenture, due 2029 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 350	$ 350
Interest rate	3.00%	3.00%
WPL [Member] | Debentures [Member] | 1.95% debenture, due 2031 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300
Interest rate	1.95%
WPL [Member] | Debentures [Member] | 6.25% debenture, due 2034 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 100	$ 100
Interest rate	6.25%	6.25%
WPL [Member] | Debentures [Member] | 6.375% debenture, due 2037 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300	$ 300
Interest rate	6.375%	6.375%
WPL [Member] | Debentures [Member] | 7.6% debenture, due 2038 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 250	$ 250
Interest rate	7.60%	7.60%
WPL [Member] | Debentures [Member] | 4.1% debenture, due 2044 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 250	$ 250
Interest rate	4.10%	4.10%
WPL [Member] | Debentures [Member] | 3.65% debenture, due 2050 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 350	$ 350
Interest rate	3.65%	3.65%
Alliant Energy Finance, LLC [Member] | Term Loan Credit Agreement [Member] | Term loan credit agreement through March 2022
Debt Instrument [Line Items]
Long-term debt	$ 300	$ 300
Interest rate	1.00%
Alliant Energy Finance, LLC [Member] | Senior Notes [Member] | 3.75% senior notes, due 2023 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 400	$ 400
Interest rate	3.75%	3.75%
Alliant Energy Finance, LLC [Member] | Senior Notes [Member] | 1.4% senior notes, due 2026 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 200	$ 200
Interest rate	1.40%	1.40%
Alliant Energy Finance, LLC [Member] | Senior Notes [Member] | 4.25% senior notes, due 2028 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300	$ 300
Interest rate	4.25%	4.25%
Corporate Services [Member] | Senior Notes [Member] | 3.45% senior notes, due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 75	$ 75
Interest rate	3.45%	3.45%
Sheboygan Power, LLC [Member] | Senior Secured Notes [Member] | 5.06% senior secured notes, due 2022 to 2024 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 24	$ 31
Interest rate	5.06%	5.06%

XML

Debt (Schedule Of Debt Maturities) (Details) $ in Millions	Dec. 31, 2021 USD ($)
2022	$ 633
2023	408
2024	509
2025	300
2026	200
IPL [Member]
2022	0
2023	0
2024	500
2025	300
2026	0
WPL [Member]
2022	250
2023	0
2024	0
2025	0
2026	0
Corporate Services [Member]
2022	75
2023	0
2024	0
2025	0
2026	0
Alliant Energy Finance, LLC [Member]
2022	308
2023	408
2024	9
2025	0
2026	$ 200

XML

Leases (Narrative) (Details)	12 Months Ended
	Dec. 31, 2021 lease_renewal_period_option
Sheboygan Falls Energy Facility [Member] | WPL [Member]
Leases [Line Items]
Finance lease, renewal options (in number of renewal periods)	2

XML

Leases (Operating Leases) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Leases [Line Items]
Operating leases assets, Property, plant and equipment, net	$ 14	$ 15
Operating leases liabilities, Other current liabilities	2	2
Operating leases liabilities, Other liabilities	12	13
Operating leases liabilities, Total	$ 14	$ 15
Operating leases, Weighted average remaining lease term	9 years	10 years
Operating leases, Weighted average discount rate, percent	4.00%	4.00%
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other	Other
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other	Other
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets
IPL [Member]
Leases [Line Items]
Operating leases assets, Property, plant and equipment, net	$ 9	$ 9
Operating leases liabilities, Other current liabilities	1	1
Operating leases liabilities, Other liabilities	8	8
Operating leases liabilities, Total	$ 9	$ 9
Operating leases, Weighted average remaining lease term	11 years	11 years
Operating leases, Weighted average discount rate, percent	4.00%	4.00%
WPL [Member]
Leases [Line Items]
Operating leases assets, Property, plant and equipment, net	$ 5	$ 6
Operating leases liabilities, Other current liabilities	1	1
Operating leases liabilities, Other liabilities	4	5
Operating leases liabilities, Total	$ 5	$ 6
Operating leases, Weighted average remaining lease term	8 years	9 years
Operating leases, Weighted average discount rate, percent	4.00%	4.00%

XML

Leases (Finance Lease) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Leases [Line Items]
Finance lease assets, Property, plant and equipment, net	$ 11
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other	Other
Finance lease liabilities, Other current liabilities	$ 1
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other	Other
Finance lease liabilities, Other liabilities	$ 11
Finance lease liabilities, Total	$ 12
Finance lease, Weighted average remaining lease term	34 years
Finance lease, Weighted average discount rate, percent	3.00%
Finance lease, Depreciation and amortization expense	$ 0
Finance lease, Interest expense	0
Finance lease, Total expense	$ 0
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets
Leased land for solar generation [Member]
Leases [Line Items]
Finance lease assets, Property, plant and equipment, net	$ 11
Finance lease liabilities, Other current liabilities	1
Finance lease liabilities, Other liabilities	11
WPL [Member]
Leases [Line Items]
Finance lease assets, Property, plant and equipment, net	32	$ 27
Finance lease liabilities, Other current liabilities	11	9
Finance lease liabilities, Other liabilities	42	42
Finance lease liabilities, Total	$ 53	$ 51
Finance lease, Weighted average remaining lease term	10 years	4 years
Finance lease, Weighted average discount rate, percent	9.00%	11.00%
Finance lease, Depreciation and amortization expense	$ 6	$ 6	$ 6
Finance lease, Interest expense	5	6	7
Finance lease, Total expense	11	12	$ 13
WPL [Member] | Sheboygan Falls Energy Facility [Member]
Leases [Line Items]
Finance lease assets, Property, plant and equipment, net	21	27
Finance lease liabilities, Other current liabilities	10	9
Finance lease liabilities, Other liabilities	31	42
WPL [Member] | Leased land for solar generation [Member]
Leases [Line Items]
Finance lease assets, Property, plant and equipment, net	11	0
Finance lease liabilities, Other current liabilities	1	0
Finance lease liabilities, Other liabilities	$ 11	$ 0

XML

Leases (Expected Maturities of Operating and Finance Lease Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Leases [Line Items]
Operating Leases Liability, 2022	$ 2
Operating Leases Liability, 2023	2
Operating Leases Liability, 2024	2
Operating Leases Liability, 2025	2
Operating Leases Liability, 2026	2
Operating Leases Liability, Thereafter	7
Operating Leases Liability, Total	17
Operating Leases Liability, Less: amount representing interest	3
Operating Leases Liability, Present value of minimum lease payments	14	$ 15
Finance Lease Liability, 2022	0
Finance Lease Liability, 2023	0
Finance Lease Liability, 2024	0
Finance Lease Liability, 2025	0
Finance Lease Liability, 2026	1
Finance Lease Liability, Thereafter	19
Finance Lease Liability, Total	20
Finance Lease Liability, Less: amount representing interest	8
Finance Lease Liability, Present value of minimum lease payments	12
IPL [Member]
Leases [Line Items]
Operating Leases Liability, 2022	1
Operating Leases Liability, 2023	1
Operating Leases Liability, 2024	1
Operating Leases Liability, 2025	1
Operating Leases Liability, 2026	1
Operating Leases Liability, Thereafter	6
Operating Leases Liability, Total	11
Operating Leases Liability, Less: amount representing interest	2
Operating Leases Liability, Present value of minimum lease payments	9	9
WPL [Member]
Leases [Line Items]
Operating Leases Liability, 2022	1
Operating Leases Liability, 2023	1
Operating Leases Liability, 2024	1
Operating Leases Liability, 2025	1
Operating Leases Liability, 2026	1
Operating Leases Liability, Thereafter	1
Operating Leases Liability, Total	6
Operating Leases Liability, Less: amount representing interest	1
Operating Leases Liability, Present value of minimum lease payments	5	6
Finance Lease Liability, 2022	15
Finance Lease Liability, 2023	15
Finance Lease Liability, 2024	15
Finance Lease Liability, 2025	6
Finance Lease Liability, 2026	1
Finance Lease Liability, Thereafter	19
Finance Lease Liability, Total	71
Finance Lease Liability, Less: amount representing interest	18
Finance Lease Liability, Present value of minimum lease payments	$ 53	$ 51

XML

Disaggregation of Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 3,669	$ 3,416	$ 3,648
IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	2,063	1,947	2,089
WPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,523	1,395	1,476
Electric [Member]
Disaggregation of Revenue [Line Items]
Revenues	3,081	2,920	3,064
Electric [Member] | IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,752	1,695	1,781
Electric [Member] | WPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,329	1,225	1,283
Electric [Member] | Retail - Residential [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,115	1,093	1,092
Electric [Member] | Retail - Residential [Member] | IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	620	602	601
Electric [Member] | Retail - Residential [Member] | WPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	495	491	491
Electric [Member] | Retail - Commercial [Member]
Disaggregation of Revenue [Line Items]
Revenues	763	718	770
Electric [Member] | Retail - Commercial [Member] | IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	508	474	510
Electric [Member] | Retail - Commercial [Member] | WPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	255	244	260
Electric [Member] | Retail - Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenues	893	841	889
Electric [Member] | Retail - Industrial [Member] | IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	505	488	504
Electric [Member] | Retail - Industrial [Member] | WPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	388	353	385
Electric [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenues	187	168	177
Electric [Member] | Wholesale [Member] | IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	57	57	64
Electric [Member] | Wholesale [Member] | WPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	130	111	113
Electric [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenues	123	100	136
Electric [Member] | Other [Member] | IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	62	74	102
Electric [Member] | Other [Member] | WPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	61	26	34
Gas [Member]
Disaggregation of Revenue [Line Items]
Revenues	456	373	455
Gas [Member] | IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	265	208	264
Gas [Member] | WPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	191	165	191
Gas [Member] | Retail - Residential [Member]
Disaggregation of Revenue [Line Items]
Revenues	257	214	259
Gas [Member] | Retail - Residential [Member] | IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	146	116	149
Gas [Member] | Retail - Residential [Member] | WPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	111	98	110
Gas [Member] | Retail - Commercial [Member]
Disaggregation of Revenue [Line Items]
Revenues	139	107	133
Gas [Member] | Retail - Commercial [Member] | IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	79	59	75
Gas [Member] | Retail - Commercial [Member] | WPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	60	48	58
Gas [Member] | Retail - Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenues	17	12	16
Gas [Member] | Retail - Industrial [Member] | IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	12	8	12
Gas [Member] | Retail - Industrial [Member] | WPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	5	4	4
Gas [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenues	43	40	47
Gas [Member] | Other [Member] | IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	28	25	28
Gas [Member] | Other [Member] | WPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	15	15	19
Other Utility [Member]
Disaggregation of Revenue [Line Items]
Revenues	49	49	46
Other Utility [Member] | IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	46	44	44
Other Utility [Member] | WPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	3	5	2
Other Utility [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenues	13	13	9
Other Utility [Member] | Other [Member] | IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	10	8	7
Other Utility [Member] | Other [Member] | WPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	3	5	2
Other Utility [Member] | Steam [Member]
Disaggregation of Revenue [Line Items]
Revenues	36	36	37
Other Utility [Member] | Steam [Member] | IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues	36	36	37
Non-Utility and Other [Member]
Disaggregation of Revenue [Line Items]
Revenues	83	74	83
Non-Utility and Other [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 83	$ 74	$ 83

XML

Income Taxes (Narrative) (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax [Line Items]
Overall income tax rate	(12.00%)	(10.00%)	11.00%
IPL [Member]
Income Tax [Line Items]
Overall income tax rate	(11.00%)	(16.00%)	8.00%
WPL [Member]
Income Tax [Line Items]
Overall income tax rate	(24.00%)	(8.00%)	17.00%
State [Member]
Income Tax [Line Items]
Overall income tax rate	9.80%	12.00%
State [Member] | IPL [Member]
Income Tax [Line Items]
Overall income tax rate	9.80%	12.00%
State [Member] | WPL [Member]
Income Tax [Line Items]
Overall income tax rate	9.80%	12.00%

XML

Income Taxes (Schedule Of Components Of Income Tax) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current tax expense (benefit):
Federal	$ 1	$ 1	$ (7)
State	3	8	24
Deferred tax expense (benefit):
Federal	9	22	70
State	15	8	42
Production tax credits	(101)	(95)	(55)
Investment tax credits	(1)	(1)	(1)
Income tax expense (benefit)	(74)	(57)	69
IPL's tax benefit riders [Member]
Current tax expense (benefit):
IPL's tax benefit riders	0	0	(4)
IPL [Member]
Current tax expense (benefit):
Federal	(21)	6	(11)
State	(1)	(1)	24
Deferred tax expense (benefit):
Federal	73	30	26
State	0	(2)	31
Production tax credits	(87)	(80)	(42)
Investment tax credits	0	0	0
Income tax expense (benefit)	(36)	(47)	24
IPL [Member] | IPL's tax benefit riders [Member]
Current tax expense (benefit):
IPL's tax benefit riders	0	0	(4)
WPL [Member]
Current tax expense (benefit):
Federal	22	(11)	12
State	6	7	13
Deferred tax expense (benefit):
Federal	(75)	(9)	31
State	11	10	6
Production tax credits	(14)	(15)	(13)
Investment tax credits	(1)	(1)	0
Income tax expense (benefit)	$ (51)	$ (19)	$ 49

XML

Income Taxes (Schedule Of Effective Income Tax Rates) (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Effective Tax Rate [Line Items]
Statutory federal income tax rate	21.00%	21.00%	21.00%
State income taxes, net of federal benefits	2.00%	2.00%	7.00%
Amortization of excess deferred taxes	(18.00%)	(13.00%)	(1.00%)
Production tax credits	(17.00%)	(17.00%)	(9.00%)
Effect of rate-making on property-related differences	(1.00%)	(3.00%)	(6.00%)
Adjustment for prior period taxes	1.00%	1.00%	1.00%
Other items, net	0.00%	(1.00%)	(1.00%)
Overall income tax rate	(12.00%)	(10.00%)	11.00%
IPL [Member]
Effective Tax Rate [Line Items]
Statutory federal income tax rate	21.00%	21.00%	21.00%
State income taxes, net of federal benefits	(1.00%)	(1.00%)	8.00%
Amortization of excess deferred taxes	(4.00%)	(5.00%)	0.00%
Production tax credits	(27.00%)	(28.00%)	(13.00%)
Effect of rate-making on property-related differences	(2.00%)	(4.00%)	(10.00%)
Adjustment for prior period taxes	2.00%	1.00%	3.00%
Other items, net	0.00%	0.00%	0.00%
Overall income tax rate	(11.00%)	(16.00%)	8.00%
WPL [Member]
Effective Tax Rate [Line Items]
Statutory federal income tax rate	21.00%	21.00%	21.00%
State income taxes, net of federal benefits	6.00%	6.00%	6.00%
Amortization of excess deferred taxes	(43.00%)	(26.00%)	(2.00%)
Production tax credits	(6.00%)	(7.00%)	(5.00%)
Effect of rate-making on property-related differences	(1.00%)	(2.00%)	(3.00%)
Adjustment for prior period taxes	0.00%	0.00%	0.00%
Other items, net	(1.00%)	0.00%	0.00%
Overall income tax rate	(24.00%)	(8.00%)	17.00%
IPL's tax benefit riders [Member]
Effective Tax Rate [Line Items]
IPL’s tax benefit riders	0.00%	0.00%	(1.00%)
IPL's tax benefit riders [Member] | IPL [Member]
Effective Tax Rate [Line Items]
IPL’s tax benefit riders	0.00%	0.00%	(1.00%)

XML

Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Deferred tax liabilities, property	$ 2,389	$ 2,232
Deferred tax liabilities, other	111	101
Total deferred tax liabilities	2,623	2,449
Deferred tax assets, federal credit carryforwards	560	454
Deferred tax assets, net operating losses carryforwards - federal	39	77
Deferred tax assets, net operating losses carryforwards - state	38	37
Deferred tax assets, other	65	73
Subtotal deferred tax assets	702	641
Deferred tax assets, valuation allowances	(6)	(6)
Total deferred tax assets	696	635
Total deferred tax liabilities, net	1,927	1,814
IPL [Member]
Deferred tax liabilities, property	1,416	1,312
Deferred tax liabilities, other	76	83
Total deferred tax liabilities	1,492	1,395
Deferred tax assets, federal credit carryforwards	345	258
Deferred tax assets, net operating losses carryforwards - federal	36	71
Deferred tax assets, net operating losses carryforwards - state	3	1
Deferred tax assets, other	25	30
Subtotal deferred tax assets	409	360
Deferred tax assets, valuation allowances	0	0
Total deferred tax assets	409	360
Total deferred tax liabilities, net	1,083	1,035
WPL [Member]
Deferred tax liabilities, property	913	854
Deferred tax liabilities, other	50	41
Total deferred tax liabilities	963	895
Deferred tax assets, federal credit carryforwards	192	175
Deferred tax assets, net operating losses carryforwards - federal	0	1
Deferred tax assets, net operating losses carryforwards - state	0	0
Deferred tax assets, other	18	18
Subtotal deferred tax assets	210	194
Deferred tax assets, valuation allowances	0	(1)
Total deferred tax assets	210	193
Total deferred tax liabilities, net	753	702
ATC Holdings [Member]
Deferred tax liabilities, ATC Holdings	$ 123	$ 116

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Income Taxes (Summary Of Tax Credit Carryforwards) (Details) $ in Millions	Dec. 31, 2021 USD ($)
Federal [Member]
Tax carryforwards, net operating losses	$ 186
Tax carryforwards, tax credits	560
Federal [Member] | IPL [Member]
Tax carryforwards, net operating losses	172
Tax carryforwards, tax credits	345
Federal [Member] | WPL [Member]
Tax carryforwards, net operating losses	1
Tax carryforwards, tax credits	192
State [Member]
Tax carryforwards, net operating losses	619
State [Member] | IPL [Member]
Tax carryforwards, net operating losses	28
State [Member] | WPL [Member]
Tax carryforwards, net operating losses	$ 2

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Income Taxes (Schedule Of Uncertain Tax Positions) (Details)	12 Months Ended
	Dec. 31, 2021
Statute of limitations, expiration period from extended due date of federal tax return	3 years
Statute of limitations, expiration period from extended due date of Iowa tax return	3 years
Statute of limitations, expiration period from extended due date of Wisconsin tax return	4 years

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Benefit Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Benefit Plans [Line Items]
Total plan assets (less than 1%), percentage of common stock	1.00%	1.00%
Common stock percentage in assets held in 401(k) saving plans	9.00%	9.00%
Unrecognized compensation cost	$ 5
Percentage of base salary and short-term cash incentive compensation	100.00%
Carrying value of deferred compensation obligations	$ 22	$ 22
Performance Shares Equity Awards [Member]
Benefit Plans [Line Items]
Performance period	3 years
Performance Shares and Performance Units Liability Awards [Member]
Benefit Plans [Line Items]
Performance period	3 years
Instrument valuation based on shares of common stock, number of shares	1
Restricted Stock Units Equity Awards [Member]
Benefit Plans [Line Items]
Performance period	3 years
Instrument valuation based on shares of common stock, number of shares	1
Restricted Stock Units Liability Awards [Member]
Benefit Plans [Line Items]
Performance period	3 years
Instrument valuation based on shares of common stock, number of shares	1
Performance Restricted Stock Units Equity Awards [Member]
Benefit Plans [Line Items]
Performance period	3 years
Instrument valuation based on shares of common stock, number of shares	1
Minimum [Member]
Benefit Plans [Line Items]
Unrecognized compensation cost recognized over a weighted average period	1 year
Minimum [Member] | Performance Shares Equity Awards [Member]
Benefit Plans [Line Items]
Actual number of shares paid out upon vesting, percentage of target shares	0.00%
Minimum [Member] | Performance Shares and Performance Units Liability Awards [Member]
Benefit Plans [Line Items]
Actual number of shares paid out upon vesting, percentage of target shares	0.00%
Minimum [Member] | Performance Restricted Stock Units Equity Awards [Member]
Benefit Plans [Line Items]
Actual number of shares paid out upon vesting, percentage of target shares	0.00%
Maximum [Member]
Benefit Plans [Line Items]
Unrecognized compensation cost recognized over a weighted average period	2 years
Maximum [Member] | Performance Shares Equity Awards [Member]
Benefit Plans [Line Items]
Actual number of shares paid out upon vesting, percentage of target shares	200.00%
Maximum [Member] | Performance Shares and Performance Units Liability Awards [Member]
Benefit Plans [Line Items]
Actual number of shares paid out upon vesting, percentage of target shares	200.00%
Maximum [Member] | Performance Restricted Stock Units Equity Awards [Member]
Benefit Plans [Line Items]
Actual number of shares paid out upon vesting, percentage of target shares	200.00%
IPL [Member]
Benefit Plans [Line Items]
Unrecognized compensation cost	$ 3
WPL [Member]
Benefit Plans [Line Items]
Unrecognized compensation cost	2
Other Postretirement Benefits Plans [Member]
Benefit Plans [Line Items]
Plan asset threshold for long-term allocation targets	5
Other Postretirement Benefits Plans [Member] | IPL [Member]
Benefit Plans [Line Items]
Plan asset threshold for long-term allocation targets	5
Other Postretirement Benefits Plans [Member] | WPL [Member]
Benefit Plans [Line Items]
Plan asset threshold for long-term allocation targets	$ 5
Omnibus Incentive Plan [Member]
Benefit Plans [Line Items]
Shares available for issuance under the Amended and Restated OIP (in shares)	9,000,000
Shares included in diluted earnings per share (in shares)	653,956

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Benefit Plans (Assumptions Used To Measure Benefit Plans) (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligations	2.91%	2.57%	3.48%
Discount rate for net periodic cost	2.57%	3.48%	4.34%
Expected rate of return on plan assets	7.10%	7.10%	7.60%
Interest crediting rate for Alliant Energy Cash Balance Pension Plan	4.18%	4.76%	5.52%
Pension Plans, Defined Benefit [Member] | IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligations	2.94%	2.61%	3.51%
Discount rate for net periodic cost	2.61%	3.51%	4.35%
Expected rate of return on plan assets	7.10%	7.10%	7.60%
Rate of compensation increase	3.30%	3.65%	3.65%
Pension Plans, Defined Benefit [Member] | WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligations	2.94%	2.64%	3.50%
Discount rate for net periodic cost	2.64%	3.50%	4.35%
Expected rate of return on plan assets	7.10%	7.10%	7.60%
Rate of compensation increase	3.30%	3.65%	3.65%
Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligations	2.81%	2.31%	3.40%
Discount rate for net periodic cost	2.31%	3.40%	4.24%
Expected rate of return on plan assets	4.80%	4.50%	5.44%
Other Postretirement Benefits Plans [Member] | IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligations	2.80%	2.28%	3.39%
Discount rate for net periodic cost	2.28%	3.39%	4.23%
Expected rate of return on plan assets	5.10%	4.50%	5.60%
Other Postretirement Benefits Plans [Member] | WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligations	2.79%	2.27%	3.39%
Discount rate for net periodic cost	2.27%	3.39%	4.23%
Expected rate of return on plan assets	4.02%	3.28%	3.81%
Minimum [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	3.30%	3.65%	3.65%
Maximum [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	4.50%	4.50%	4.50%

XML

Benefit Plans (Defined Benefit Pension And Other Postretirement Benefits Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 11	$ 11	$ 10
Interest cost	34	43	50
Expected return on plan assets	(69)	(70)	(60)
Amortization of prior service cost (credit)	0	0	(1)
Amortization of actuarial loss	39	34	36
Settlement losses	0	12	0
Total	15	30	35
Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	3	3
Interest cost	5	7	9
Expected return on plan assets	(5)	(5)	(5)
Amortization of prior service cost (credit)	0	0	0
Amortization of actuarial loss	5	3	3
Settlement losses	0	0	0
Total	9	8	10
IPL [Member] | Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	7	7	6
Interest cost	16	20	23
Expected return on plan assets	(32)	(33)	(28)
Amortization of actuarial loss	17	15	15
Settlement losses	0	7	0
Total	8	16	16
IPL [Member] | Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	1
Interest cost	2	3	3
Expected return on plan assets	(3)	(4)	(4)
Amortization of actuarial loss	2	1	2
Settlement losses	0	0	0
Total	2	1	2
WPL [Member] | Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	4	3
Interest cost	15	19	21
Expected return on plan assets	(31)	(31)	(26)
Amortization of prior service cost (credit)	0	0	0
Amortization of actuarial loss	19	16	18
Total	7	8	16
WPL [Member] | Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2	1
Interest cost	2	3	3
Expected return on plan assets	0	(1)	(1)
Amortization of prior service cost (credit)	0	(1)	0
Amortization of actuarial loss	2	2	2
Total	$ 5	$ 5	$ 5

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Benefit Plans (Funded Status of Benefits Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligations	$ 1,251	$ 1,351
Change in benefit obligation:
Net benefit obligation at January 1	1,351	1,280
Service cost	11	11	$ 10
Interest cost	34	43	50
Plan participants' contributions	0	0
Actuarial (gain) loss	(46)	132
Gross benefits paid	(99)	(115)
Net benefit obligation at December 31	1,251	1,351	1,280
Change in plan assets:
Fair value of plan assets at January 1	984	931
Actual return on plan assets	87	108
Employer contributions	39	60
Plan participants' contributions	0	0
Gross benefits paid	(99)	(115)
Fair value of plan assets at December 31	1,011	984	931
Under funded status at December 31	(240)	(367)
Fair value of plan assets	1,011	984	931
Pension Plans, Defined Benefit [Member] | IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligations	567	615
Change in benefit obligation:
Net benefit obligation at January 1	615	581
Service cost	7	7	6
Interest cost	16	20	23
Plan participants' contributions	0	0
Actuarial (gain) loss	(23)	60
Gross benefits paid	(48)	(53)
Net benefit obligation at December 31	567	615	581
Change in plan assets:
Fair value of plan assets at January 1	453	436
Actual return on plan assets	40	51
Employer contributions	17	19
Plan participants' contributions	0	0
Gross benefits paid	(48)	(53)
Fair value of plan assets at December 31	462	453	436
Under funded status at December 31	(105)	(162)
Fair value of plan assets	462	453	436
Pension Plans, Defined Benefit [Member] | WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligations	546	588
Change in benefit obligation:
Net benefit obligation at January 1	588	550
Service cost	4	4	3
Interest cost	15	19	21
Plan participants' contributions	0	0
Actuarial (gain) loss	(18)	55
Gross benefits paid	(43)	(40)
Net benefit obligation at December 31	546	588	550
Change in plan assets:
Fair value of plan assets at January 1	436	406
Actual return on plan assets	39	48
Employer contributions	18	22
Plan participants' contributions	0	0
Gross benefits paid	(43)	(40)
Fair value of plan assets at December 31	450	436	406
Under funded status at December 31	(96)	(152)
Fair value of plan assets	450	436	406
Other Postretirement Benefits Plans [Member]
Change in benefit obligation:
Net benefit obligation at January 1	227	214
Service cost	4	3	3
Interest cost	5	7	9
Plan participants' contributions	5	4
Actuarial (gain) loss	(12)	18
Gross benefits paid	(19)	(19)
Net benefit obligation at December 31	210	227	214
Change in plan assets:
Fair value of plan assets at January 1	108	105
Actual return on plan assets	4	11
Employer contributions	8	7
Plan participants' contributions	5	4
Gross benefits paid	(19)	(19)
Fair value of plan assets at December 31	106	108	105
Under funded status at December 31	(104)	(119)
Fair value of plan assets	106	108	105
Other Postretirement Benefits Plans [Member] | IPL [Member]
Change in benefit obligation:
Net benefit obligation at January 1	91	86
Service cost	1	1	1
Interest cost	2	3	3
Plan participants' contributions	2	1
Actuarial (gain) loss	(4)	8
Gross benefits paid	(8)	(8)
Net benefit obligation at December 31	84	91	86
Change in plan assets:
Fair value of plan assets at January 1	74	72
Actual return on plan assets	4	7
Employer contributions	2	2
Plan participants' contributions	2	1
Gross benefits paid	(8)	(8)
Fair value of plan assets at December 31	74	74	72
Under funded status at December 31	(10)	(17)
Fair value of plan assets	74	74	72
Other Postretirement Benefits Plans [Member] | WPL [Member]
Change in benefit obligation:
Net benefit obligation at January 1	89	85
Service cost	1	2	1
Interest cost	2	3	3
Plan participants' contributions	2	2
Actuarial (gain) loss	(5)	5
Gross benefits paid	(8)	(8)
Net benefit obligation at December 31	81	89	85
Change in plan assets:
Fair value of plan assets at January 1	18	17
Actual return on plan assets	0	2
Employer contributions	5	5
Plan participants' contributions	2	2
Gross benefits paid	(8)	(8)
Fair value of plan assets at December 31	17	18	17
Under funded status at December 31	(64)	(71)
Fair value of plan assets	$ 17	$ 18	$ 17

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Benefit Plans (Amounts Recognized On The Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Amounts recognized on the balance sheets consist of:
Pension and other benefit obligations	$ (374)	$ (511)
Pension Plans, Defined Benefit [Member]
Amounts recognized on the balance sheets consist of:
Non-current assets	0	0
Current liabilities	(2)	(2)
Pension and other benefit obligations	(238)	(365)
Net amounts recognized at December 31	(240)	(367)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	429	533
Prior service credit	(4)	(5)
Net amount recognized at December 31	425	528
Other Postretirement Benefits Plans [Member]
Amounts recognized on the balance sheets consist of:
Non-current assets	13	8
Current liabilities	(8)	(8)
Pension and other benefit obligations	(109)	(119)
Net amounts recognized at December 31	(104)	(119)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	38	54
Prior service credit	(1)	(1)
Net amount recognized at December 31	37	53
IPL [Member]
Amounts recognized on the balance sheets consist of:
Pension and other benefit obligations	(127)	(186)
IPL [Member] | Pension Plans, Defined Benefit [Member]
Amounts recognized on the balance sheets consist of:
Non-current assets	0	0
Current liabilities	0	(1)
Pension and other benefit obligations	(105)	(161)
Net amounts recognized at December 31	(105)	(162)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	180	228
Prior service credit	(1)	(1)
Net amount recognized at December 31	179	227
IPL [Member] | Other Postretirement Benefits Plans [Member]
Amounts recognized on the balance sheets consist of:
Non-current assets	10	4
Current liabilities	(2)	(2)
Pension and other benefit obligations	(18)	(19)
Net amounts recognized at December 31	(10)	(17)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	13	20
Prior service credit	0	0
Net amount recognized at December 31	13	20
WPL [Member]
Amounts recognized on the balance sheets consist of:
Pension and other benefit obligations	(159)	(222)
WPL [Member] | Pension Plans, Defined Benefit [Member]
Amounts recognized on the balance sheets consist of:
Non-current assets	0	0
Current liabilities	0	0
Pension and other benefit obligations	(96)	(152)
Net amounts recognized at December 31	(96)	(152)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	188	233
Prior service credit	(1)	(1)
Net amount recognized at December 31	187	232
WPL [Member] | Other Postretirement Benefits Plans [Member]
Amounts recognized on the balance sheets consist of:
Non-current assets	3	3
Current liabilities	(6)	(6)
Pension and other benefit obligations	(61)	(68)
Net amounts recognized at December 31	(64)	(71)
Amounts recognized in Regulatory Assets consist of:
Net actuarial loss	18	25
Prior service credit	(1)	(1)
Net amount recognized at December 31	$ 17	$ 24

XML

Benefit Plans (Accumulated Benefit Obligations) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligations	$ 1,214	$ 1,305
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	1,214	1,305
Fair value of plan assets	1,011	984
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	1,251	1,351
Fair value of plan assets	1,011	984
Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligations	210	227
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	210	227
Fair value of plan assets	106	108
IPL [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligations	546	589
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	546	589
Fair value of plan assets	462	453
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	567	615
Fair value of plan assets	462	453
IPL [Member] | Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligations	84	91
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	84	91
Fair value of plan assets	74	74
WPL [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligations	532	573
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	532	573
Fair value of plan assets	450	436
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	546	588
Fair value of plan assets	450	436
WPL [Member] | Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligations	81	89
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	81	89
Fair value of plan assets	$ 17	$ 18

XML

Benefit Plans (Regulatory Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets	$ 35	$ 44
WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets	$ 30	$ 34

XML

Benefit Plans (Estimated Future Funding) (Details) - Forecast [Member] $ in Millions	Dec. 31, 2022 USD ($)
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated funding for calendar year 2022	$ 2
Defined Benefit Pension Plans [Member] | IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated funding for calendar year 2022	0
Defined Benefit Pension Plans [Member] | WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated funding for calendar year 2022	0
Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated funding for calendar year 2022	8
Other Postretirement Benefits Plans [Member] | IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated funding for calendar year 2022	2
Other Postretirement Benefits Plans [Member] | WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated funding for calendar year 2022	$ 6

XML

Benefit Plans (Expected Benefit Payments) (Details) $ in Millions	Dec. 31, 2021 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Expected benefit payments, 2022	$ 103
Expected benefit payments, 2023	100
Expected benefit payments, 2024	99
Expected benefit payments, 2025	99
Expected benefit payments, 2026	99
Expected benefit payments, 2027 - 2031	458
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected benefit payments, 2022	85
Expected benefit payments, 2023	83
Expected benefit payments, 2024	82
Expected benefit payments, 2025	82
Expected benefit payments, 2026	83
Expected benefit payments, 2027 - 2031	387
Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected benefit payments, 2022	18
Expected benefit payments, 2023	17
Expected benefit payments, 2024	17
Expected benefit payments, 2025	17
Expected benefit payments, 2026	16
Expected benefit payments, 2027 - 2031	71
IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected benefit payments, 2022	48
Expected benefit payments, 2023	47
Expected benefit payments, 2024	46
Expected benefit payments, 2025	46
Expected benefit payments, 2026	45
Expected benefit payments, 2027 - 2031	202
IPL [Member] | Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected benefit payments, 2022	41
Expected benefit payments, 2023	40
Expected benefit payments, 2024	39
Expected benefit payments, 2025	39
Expected benefit payments, 2026	38
Expected benefit payments, 2027 - 2031	174
IPL [Member] | Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected benefit payments, 2022	7
Expected benefit payments, 2023	7
Expected benefit payments, 2024	7
Expected benefit payments, 2025	7
Expected benefit payments, 2026	7
Expected benefit payments, 2027 - 2031	28
WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected benefit payments, 2022	44
Expected benefit payments, 2023	43
Expected benefit payments, 2024	42
Expected benefit payments, 2025	42
Expected benefit payments, 2026	40
Expected benefit payments, 2027 - 2031	190
WPL [Member] | Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected benefit payments, 2022	37
Expected benefit payments, 2023	36
Expected benefit payments, 2024	35
Expected benefit payments, 2025	35
Expected benefit payments, 2026	34
Expected benefit payments, 2027 - 2031	163
WPL [Member] | Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected benefit payments, 2022	7
Expected benefit payments, 2023	7
Expected benefit payments, 2024	7
Expected benefit payments, 2025	7
Expected benefit payments, 2026	6
Expected benefit payments, 2027 - 2031	$ 27

XML

Benefit Plans (Allocation Of Plan Assets) (Details)	Dec. 31, 2021
Pension Plans, Defined Benefit [Member] | Cash and equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation, percentage	3.00%
Pension Plans, Defined Benefit [Member] | Equity securites - U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation, percentage	34.00%
Pension Plans, Defined Benefit [Member] | Equity securities - international [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation, percentage	21.00%
Pension Plans, Defined Benefit [Member] | Global asset securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation, percentage	9.00%
Pension Plans, Defined Benefit [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation, percentage	33.00%
Other Postretirement Benefits Plans [Member] | Cash and equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation, percentage	1.00%
Other Postretirement Benefits Plans [Member] | Equity securites - U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation, percentage	35.00%
Other Postretirement Benefits Plans [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation, percentage	64.00%
Minimum [Member] | Pension Plans, Defined Benefit [Member] | Cash and equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	0.00%
Minimum [Member] | Pension Plans, Defined Benefit [Member] | Equity securites - U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	14.00%
Minimum [Member] | Pension Plans, Defined Benefit [Member] | Equity securities - international [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	11.00%
Minimum [Member] | Pension Plans, Defined Benefit [Member] | Global asset securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	5.00%
Minimum [Member] | Pension Plans, Defined Benefit [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	25.00%
Minimum [Member] | Other Postretirement Benefits Plans [Member] | Cash and equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	0.00%
Minimum [Member] | Other Postretirement Benefits Plans [Member] | Equity securites - U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	0.00%
Minimum [Member] | Other Postretirement Benefits Plans [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	40.00%
Maximum [Member] | Pension Plans, Defined Benefit [Member] | Cash and equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	5.00%
Maximum [Member] | Pension Plans, Defined Benefit [Member] | Equity securites - U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	54.00%
Maximum [Member] | Pension Plans, Defined Benefit [Member] | Equity securities - international [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	31.00%
Maximum [Member] | Pension Plans, Defined Benefit [Member] | Global asset securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	15.00%
Maximum [Member] | Pension Plans, Defined Benefit [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	45.00%
Maximum [Member] | Other Postretirement Benefits Plans [Member] | Cash and equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	5.00%
Maximum [Member] | Other Postretirement Benefits Plans [Member] | Equity securites - U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	55.00%
Maximum [Member] | Other Postretirement Benefits Plans [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target range allocation, percentage	100.00%

XML

Benefit Plans (Fair Value Of Plan Assets By Asset Category And Fair Value Hierarchy Level) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 1,011.0	$ 984.0	$ 931.0
Pension Plans, Defined Benefit [Member] | Assets measured at net asset value [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	477.0	426.0
Pension Plans, Defined Benefit [Member] | Cash and equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	35.0	46.0
Pension Plans, Defined Benefit [Member] | Cash and equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | Cash and equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	35.0	46.0
Pension Plans, Defined Benefit [Member] | Cash and equivalents [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | Equity securites - U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	256.0	182.0
Pension Plans, Defined Benefit [Member] | Equity securites - U.S. [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	256.0	182.0
Pension Plans, Defined Benefit [Member] | Equity securites - U.S. [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | Equity securites - U.S. [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | Equity securities - international [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	151.0
Pension Plans, Defined Benefit [Member] | Equity securities - international [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	151.0
Pension Plans, Defined Benefit [Member] | Equity securities - international [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | Equity securities - international [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | Global asset securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	52.0	45.0
Pension Plans, Defined Benefit [Member] | Global asset securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	52.0	45.0
Pension Plans, Defined Benefit [Member] | Global asset securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | Global asset securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	191.0	134.0
Pension Plans, Defined Benefit [Member] | Fixed income securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	47.0	56.0
Pension Plans, Defined Benefit [Member] | Fixed income securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	144.0	78.0
Pension Plans, Defined Benefit [Member] | Fixed income securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | Subtotal [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	534.0	558.0
Pension Plans, Defined Benefit [Member] | Subtotal [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	355.0	434.0
Pension Plans, Defined Benefit [Member] | Subtotal [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	179.0	124.0
Pension Plans, Defined Benefit [Member] | Subtotal [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | Accrued investment income [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0	1.0
Pension Plans, Defined Benefit [Member] | IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	462.0	453.0	436.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Assets measured at net asset value [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	218.0	196.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Cash and equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	16.0	21.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Cash and equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Cash and equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	16.0	21.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Cash and equivalents [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Equity securites - U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	117.0	84.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Equity securites - U.S. [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	117.0	84.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Equity securites - U.S. [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Equity securites - U.S. [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Equity securities - international [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	69.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Equity securities - international [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	69.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Equity securities - international [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Equity securities - international [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Global asset securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24.0	21.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Global asset securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24.0	21.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Global asset securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Global asset securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	87.0	62.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Fixed income securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	21.0	26.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Fixed income securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	66.0	36.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Fixed income securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Subtotal [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	244.0	257.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Subtotal [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	162.0	200.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Subtotal [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	82.0	57.0
Pension Plans, Defined Benefit [Member] | IPL [Member] | Subtotal [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	450.0	436.0	406.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Assets measured at net asset value [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	212.0	189.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Cash and equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	16.0	20.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Cash and equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Cash and equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	16.0	20.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Cash and equivalents [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Equity securites - U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	114.0	81.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Equity securites - U.S. [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	114.0	81.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Equity securites - U.S. [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Equity securites - U.S. [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Equity securities - international [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	67.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Equity securities - international [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	67.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Equity securities - international [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Equity securities - international [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Global asset securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	23.0	20.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Global asset securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	23.0	20.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Global asset securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Global asset securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	85.0	59.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Fixed income securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	21.0	25.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Fixed income securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	64.0	34.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Fixed income securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Subtotal [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	238.0	247.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Subtotal [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	158.0	193.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Subtotal [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	80.0	54.0
Pension Plans, Defined Benefit [Member] | WPL [Member] | Subtotal [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	106.0	108.0	105.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	70.0	78.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7.0	3.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Assets measured at net asset value [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	29.0	27.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Cash and equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5.0	2.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Cash and equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Cash and equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5.0	2.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Cash and equivalents [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity securites - U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	11.0	4.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity securites - U.S. [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	11.0	4.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity securites - U.S. [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity securites - U.S. [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity securities - international [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	3.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity securities - international [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	3.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity securities - international [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity securities - international [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Global asset securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Global asset securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Global asset securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Global asset securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	60.0	72.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fixed income securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	58.0	71.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fixed income securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2.0	1.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fixed income securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Subtotal [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	77.0	81.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	74.0	74.0	72.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	50.0	51.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0	1.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Assets measured at net asset value [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	23.0	22.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Cash and equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0	1.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Cash and equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Cash and equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0	1.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Cash and equivalents [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Equity securites - U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Equity securites - U.S. [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Equity securites - U.S. [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Equity securites - U.S. [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	42.0	51.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Fixed income securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	42.0	51.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Fixed income securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Fixed income securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | IPL [Member] | Subtotal [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	51.0	52.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17.0	18.0	$ 17.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	16.0	18.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member] | Cash and equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member] | Cash and equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member] | Cash and equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member] | Cash and equivalents [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member] | Equity securites - U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member] | Equity securites - U.S. [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member] | Equity securites - U.S. [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member] | Equity securites - U.S. [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15.0	18.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member] | Fixed income securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15.0	18.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member] | Fixed income securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Other Postretirement Benefit Plans, Defined Benefit [Member] | WPL [Member] | Fixed income securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Defined Benefit Plan Due To Brokers Net [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ (1.0)	$ (1.0)

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Benefit Plans (Employees Participate In Defined Contribution Retirement Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
401(k) costs	$ 26	$ 25	$ 25
IPL [Member]
401(k) costs	13	13	13
WPL [Member]
401(k) costs	$ 12	$ 12	$ 12

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Benefit Plans (Recognized Compensation Expense And Income Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Compensation expense	$ 14	$ 16	$ 26
Income tax benefits	4	4	7
IPL [Member]
Compensation expense	8	9	15
Income tax benefits	2	2	4
WPL [Member]
Compensation expense	6	6	10
Income tax benefits	$ 2	$ 2	$ 3

XML

Benefit Plans (Summary Of Performance Shares and Performance Units Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Performance Shares Equity Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested, January 1 (in shares/awards)	129,156	74,193	0
Nonvested, January 1, weighted average grant date fair value (in dollars per share)	$ 54.63	$ 47.44	$ 0
Granted (in shares/awards)	73,112	56,204	91,816
Granted, weighted average grant date fair value (in dollars per share)	$ 46.19	$ 64.04	$ 47.23
Forfeited (in shares/awards)	(5,839)	(1,241)	(17,623)
Forfeited, weighted average grant date fair value (in dollars per share)	$ 51.07	$ 50.94	$ 46.35
Nonvested, December 31 (in shares/awards)	196,429	129,156	74,193
Nonvested, December 31, weighted average grant date fair value (in dollars per share)	$ 51.59	$ 54.63	$ 47.44
Performance Shares Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested, January 1 (in shares/awards)	68,307	131,872	203,188
Vested (in shares/awards)	(68,307)	(63,565)	(66,322)
Forfeited (in shares/awards)	0	0	(4,994)
Nonvested, December 31 (in shares/awards)	0	68,307	131,872
Performance Units Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested, January 1 (in shares/awards)	16,801	34,574	57,761
Vested (in shares/awards)	(16,801)	(16,661)	(20,131)
Forfeited (in shares/awards)	0	(1,112)	(3,056)
Nonvested, December 31 (in shares/awards)	0	16,801	34,574

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Benefit Plans (Summary Of Performance Shares and Performance Units Vested Awards) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Performance Shares Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares/awards)	68,307	63,565	66,322
Performance Units Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares/awards)	16,801	16,661	20,131
2018 Grant [Member] | Performance Shares Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares/awards)	68,307
Vested percentage of the target	172.50%
Cash and stock payout value	$ 7
Cash payout value	$ 5
Common stock shares from vested performance shares (in shares)	13,644
2018 Grant [Member] | Performance Units Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares/awards)	16,801
Vested percentage of the target	172.50%
Cash and stock payout value	$ 2
Cash payout value	$ 2
2017 Grant [Member] | Performance Shares Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares/awards)		63,565
Vested percentage of the target		155.00%
Cash and stock payout value		$ 6
Cash payout value		$ 5
Common stock shares from vested performance shares (in shares)		9,543
2017 Grant [Member] | Performance Units Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares/awards)		16,661
Vested percentage of the target		155.00%
Cash and stock payout value		$ 2
Cash payout value		$ 2
2016 Grant [Member] | Performance Shares Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares/awards)			66,322
Vested percentage of the target			142.50%
Cash and stock payout value			$ 4
Cash payout value			$ 4
Common stock shares from vested performance shares (in shares)			6,447
2016 Grant [Member] | Performance Units Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares/awards)			20,131
Vested percentage of the target			142.50%
Cash and stock payout value			$ 1
Cash payout value			$ 1

XML

Benefit Plans (Summary of Restricted Stock Units) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restricted Stock Units Equity Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested, January 1 (in shares/awards)	146,549	89,281	0
Nonvested, January 1, weighted average grant date fair value (in dollars per share)	$ 51.54	$ 46.04	$ 0
Granted (in shares/awards)	80,152	61,056	105,348
Granted, weighted average grant date fair value (in dollars per share)	$ 48.65	$ 59.42	$ 45.98
Forfeited (in shares/awards)	(8,882)	(3,788)	(16,067)
Forfeited, weighted average grant date fair value (in dollars per share)	$ 49.84	$ 49.01	$ 45.63
Nonvested, December 31 (in shares/awards)	217,819	146,549	89,281
Nonvested, December 31, weighted average grant date fair value (in dollars per share)	$ 50.54	$ 51.54	$ 46.04
Restricted Stock Units Liability Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested, January 1 (in shares/awards)	58,550	113,033	174,163
Vested (in shares/awards)	(58,550)	(54,483)	(56,849)
Forfeited (in shares/awards)	0	0	(4,281)
Nonvested, December 31 (in shares/awards)	0	58,550	113,033

XML

Benefit Plans (Summary of Performance Restricted Stock Units) (Details) - Performance Restricted Stock Units Equity Awards [Member] - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested, January 1 (in shares/awards)	197,463	206,065	203,188
Nonvested, January 1, weighted average grant date fair value (in dollars per share)	$ 47.31	$ 41.50	$ 37.23
Granted (in shares/awards)	73,112	56,204	91,816
Granted, weighted average grant date fair value (in dollars per share)	$ 48.66	$ 59.37	$ 46.10
Vested (in shares/awards)	(68,307)	(63,565)	(66,322)
Vested, weighted average grant date fair value (in dollars per share)	$ 38.60	$ 39.12	$ 33.93
Forfeited (in shares/awards)	(5,839)	(1,241)	(22,617)
Forfeited, weighted average grant date fair value (in dollars per share)	$ 50.46	$ 49.25	$ 44.00
Nonvested, December 31 (in shares/awards)	196,429	197,463	206,065
Nonvested, December 31, weighted average grant date fair value (in dollars per share)	$ 50.74	$ 47.31	$ 41.50

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Benefit Plans (Carrying Value And Fair Market Value Of The Deferred Compensation Obligation for Company Stock Account) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Carrying value of deferred compensation obligation	$ 12	$ 11
Fair market value of deferred compensation obligation	$ 24	$ 20

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Asset Retirement Obligations (Reconciliation Of Changes In Asset Retirement Obligations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance, January 1	$ 251	$ 196
Revisions in estimated cash flows	50	13
Liabilities settled	(17)	(13)
Liabilities incurred	3	48
Accretion expense	7	7
Balance, December 31	294	251
IPL [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance, January 1	177	134
Revisions in estimated cash flows	44	9
Liabilities settled	(13)	(9)
Liabilities incurred	0	38
Accretion expense	5	5
Balance, December 31	213	177
WPL [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance, January 1	74	62
Revisions in estimated cash flows	6	4
Liabilities settled	(4)	(4)
Liabilities incurred	3	10
Accretion expense	2	2
Balance, December 31	$ 81	$ 74

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Derivative Instruments (Notional Amounts Of Derivative Instruments) (Details) - Commodity [Member] gal in Thousands, T in Thousands, MWh in Thousands, Dekatherms in Thousands	12 Months Ended
	Dec. 31, 2021 Dekatherms MWh T gal
FTRs (MWhs) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs) | MWh	9,135
FTRs (MWhs) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs) | MWh	2,647
FTRs (MWhs) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs) | MWh	6,488
Gas (Dths) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Dths) | Dekatherms	191,670
Gas (Dths) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Dths) | Dekatherms	100,560
Gas (Dths) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Dths) | Dekatherms	91,110
Coal (Tons) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Tons) | T	3,193
Coal (Tons) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Tons) | T	1,270
Coal (Tons) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Tons) | T	1,923
Diesel Fuel (gallons) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Gallons) | gal	3,024
Diesel Fuel (gallons) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Gallons) | gal	0
Diesel Fuel (gallons) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Gallons) | gal	3,024

XML

Derivative Instruments (Fair Value Of Financial Instruments) (Details) - Commodity Contracts [Member] - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Current derivative assets	$ 113	$ 24
Non-current derivative assets	63	10
Current derivative liabilities	8	9
Non-current derivative liabilities	1	16
IPL [Member]
Derivatives, Fair Value [Line Items]
Current derivative assets	48	20
Non-current derivative assets	36	9
Current derivative liabilities	4	3
Non-current derivative liabilities	0	9
WPL [Member]
Derivatives, Fair Value [Line Items]
Current derivative assets	65	4
Non-current derivative assets	27	1
Current derivative liabilities	4	6
Non-current derivative liabilities	$ 1	$ 7

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Fair Value Measurements (Recurring Fair Value Measurements) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Assets:
Money market fund investments	$ 32	$ 44
Deferred proceeds	214	188
Liabilities and equity:
Long-term debt (including current maturities)	8,330	8,109
Commodity Contracts [Member]
Assets:
Derivatives	176	34
Liabilities and equity:
Derivatives	9	25
Level 1 [Member]
Assets:
Money market fund investments	32	44
Deferred proceeds	0	0
Liabilities and equity:
Long-term debt (including current maturities)	0	0
Level 1 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	0	0
Liabilities and equity:
Derivatives	0	0
Level 2 [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	0	0
Liabilities and equity:
Long-term debt (including current maturities)	8,329	8,107
Level 2 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	146	5
Liabilities and equity:
Derivatives	8	25
Level 3 [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	214	188
Liabilities and equity:
Long-term debt (including current maturities)	1	2
Level 3 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	30	29
Liabilities and equity:
Derivatives	1	0
Carrying Amount [Member]
Assets:
Money market fund investments	32	44
Deferred proceeds	214	188
Liabilities and equity:
Long-term debt (including current maturities)	7,368	6,777
Carrying Amount [Member] | Commodity Contracts [Member]
Assets:
Derivatives	176	34
Liabilities and equity:
Derivatives	9	25
IPL [Member]
Assets:
Money market fund investments	32	44
Deferred proceeds	214	188
Liabilities and equity:
Long-term debt (including current maturities)	4,124	4,021
IPL [Member] | Commodity Contracts [Member]
Assets:
Derivatives	84	29
Liabilities and equity:
Derivatives	4	12
IPL [Member] | Level 1 [Member]
Assets:
Money market fund investments	32	44
Deferred proceeds	0	0
Liabilities and equity:
Long-term debt (including current maturities)	0	0
IPL [Member] | Level 1 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	0	0
Liabilities and equity:
Derivatives	0	0
IPL [Member] | Level 2 [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	0	0
Liabilities and equity:
Long-term debt (including current maturities)	4,124	4,021
IPL [Member] | Level 2 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	65	3
Liabilities and equity:
Derivatives	3	12
IPL [Member] | Level 3 [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	214	188
Liabilities and equity:
Long-term debt (including current maturities)	0	0
IPL [Member] | Level 3 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	19	26
Liabilities and equity:
Derivatives	1	0
IPL [Member] | Carrying Amount [Member]
Assets:
Money market fund investments	32	44
Deferred proceeds	214	188
Liabilities and equity:
Long-term debt (including current maturities)	3,643	3,345
IPL [Member] | Carrying Amount [Member] | Commodity Contracts [Member]
Assets:
Derivatives	84	29
Liabilities and equity:
Derivatives	4	12
WPL [Member]
Liabilities and equity:
Long-term debt (including current maturities)	2,862	2,690
WPL [Member] | Commodity Contracts [Member]
Assets:
Derivatives	92	5
Liabilities and equity:
Derivatives	5	13
WPL [Member] | Level 1 [Member]
Liabilities and equity:
Long-term debt (including current maturities)	0	0
WPL [Member] | Level 1 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	0	0
Liabilities and equity:
Derivatives	0	0
WPL [Member] | Level 2 [Member]
Liabilities and equity:
Long-term debt (including current maturities)	2,862	2,690
WPL [Member] | Level 2 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	81	2
Liabilities and equity:
Derivatives	5	13
WPL [Member] | Level 3 [Member]
Liabilities and equity:
Long-term debt (including current maturities)	0	0
WPL [Member] | Level 3 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	11	3
Liabilities and equity:
Derivatives	0	0
WPL [Member] | Carrying Amount [Member]
Liabilities and equity:
Long-term debt (including current maturities)	2,429	2,130
WPL [Member] | Carrying Amount [Member] | Commodity Contracts [Member]
Assets:
Derivatives	92	5
Liabilities and equity:
Derivatives	$ 5	$ 13

XML

Fair Value Measurements (Fair Value Measurements Using Significant Unobservable Inputs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Commodity Contracts Derivative Assets and (Liabilities), net [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, January 1	$ 29	$ 21
Total net gains (losses) included in changes in net assets (realized/unrealized)	6	11
Purchases	21	14
Sales	(1)	(1)
Settlements	(26)	(16)
Ending balance, December 31	29	29
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at December 31	6	11
Commodity Contracts Derivative Assets and (Liabilities), net [Member] | IPL [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, January 1	26	18
Total net gains (losses) included in changes in net assets (realized/unrealized)	(3)	10
Purchases	16	11
Sales	(1)	(1)
Settlements	(20)	(12)
Ending balance, December 31	18	26
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at December 31	(3)	10
Commodity Contracts Derivative Assets and (Liabilities), net [Member] | WPL [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, January 1	3	3
Total net gains (losses) included in changes in net assets (realized/unrealized)	9	1
Purchases	5	3
Settlements	(6)	(4)
Ending balance, December 31	11	3
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at December 31	9	1
Deferred Proceeds [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, January 1	188	188
Total net gains (losses) included in changes in net assets (realized/unrealized)	0	0
Purchases	0	0
Sales	0	0
Settlements	26	0
Ending balance, December 31	214	188
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at December 31	0	0
Deferred Proceeds [Member] | IPL [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, January 1	188	188
Total net gains (losses) included in changes in net assets (realized/unrealized)	0	0
Purchases	0	0
Sales	0	0
Settlements	26	0
Ending balance, December 31	214	188
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at December 31	$ 0	$ 0

XML

Fair Value Measurements (Fair Value Of Net Derivative Assets (Liabilities)) (Details) - Commodity Contracts [Member] - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, net derivative assets	$ 29	$ 29	$ 21
Excluding FTRs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, net derivative assets	9	18
FTRs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, net derivative assets	20	11
IPL [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, net derivative assets	18	26	18
IPL [Member] | Excluding FTRs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, net derivative assets	8	17
IPL [Member] | FTRs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, net derivative assets	10	9
WPL [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, net derivative assets	11	3	$ 3
WPL [Member] | Excluding FTRs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, net derivative assets	1	1
WPL [Member] | FTRs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, net derivative assets	$ 10	$ 2

XML

Commitments And Contingencies (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)
Workforce Subject to Collective Bargaining Arrangements [Member]
Long-term Purchase Commitment [Line Items]
Employees covered by collective bargaining agreement	54.00%
Workforce Subject to Collective Bargaining Arrangements Expiring within One Year [Member]
Long-term Purchase Commitment [Line Items]
Employees covered by collective bargaining agreement	26.00%
Whiting Petroleum Affiliate [Member]
Long-term Purchase Commitment [Line Items]
Partnership share, percent	6.00%
Obligations, maximum	$ 60
Credit loss liability	5
Capital Purchase Commitment [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments	$ 178
IPL [Member] | Workforce Subject to Collective Bargaining Arrangements [Member]
Long-term Purchase Commitment [Line Items]
Employees covered by collective bargaining agreement	69.00%
WPL [Member] | Workforce Subject to Collective Bargaining Arrangements [Member]
Long-term Purchase Commitment [Line Items]
Employees covered by collective bargaining agreement	83.00%
WPL [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring within One Year [Member]
Long-term Purchase Commitment [Line Items]
Employees covered by collective bargaining agreement	83.00%
WPL [Member] | Capital Purchase Commitment [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments	$ 177
Indemnification Agreement [Member]
Long-term Purchase Commitment [Line Items]
Obligations, maximum	67
Indemnification Agreement [Member] | Purchased Power [Member]
Long-term Purchase Commitment [Line Items]
Obligations, maximum	$ 17

XML

Commitments And Contingencies (Other Purchase Commitments) (Details) $ in Millions	Dec. 31, 2021 USD ($)
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2022	$ 452
Minimum future commitments, 2023	256
Minimum future commitments, 2024	177
Minimum future commitments, 2025	110
Minimum future commitments, 2026	90
Minimum future commitments, Thereafter	200
Minimum future commitments, Total	1,285
Individual commitments incurred	1
Natural Gas [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2022	307
Minimum future commitments, 2023	196
Minimum future commitments, 2024	144
Minimum future commitments, 2025	102
Minimum future commitments, 2026	88
Minimum future commitments, Thereafter	175
Minimum future commitments, Total	1,012
Coal [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2022	63
Minimum future commitments, 2023	46
Minimum future commitments, 2024	25
Minimum future commitments, 2025	3
Minimum future commitments, 2026	0
Minimum future commitments, Thereafter	0
Minimum future commitments, Total	137
Other [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2022	82
Minimum future commitments, 2023	14
Minimum future commitments, 2024	8
Minimum future commitments, 2025	5
Minimum future commitments, 2026	2
Minimum future commitments, Thereafter	25
Minimum future commitments, Total	136
IPL [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2022	214
Minimum future commitments, 2023	139
Minimum future commitments, 2024	103
Minimum future commitments, 2025	57
Minimum future commitments, 2026	44
Minimum future commitments, Thereafter	88
Minimum future commitments, Total	645
IPL [Member] | Natural Gas [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2022	148
Minimum future commitments, 2023	108
Minimum future commitments, 2024	84
Minimum future commitments, 2025	52
Minimum future commitments, 2026	42
Minimum future commitments, Thereafter	65
Minimum future commitments, Total	499
IPL [Member] | Coal [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2022	32
Minimum future commitments, 2023	27
Minimum future commitments, 2024	17
Minimum future commitments, 2025	3
Minimum future commitments, 2026	0
Minimum future commitments, Thereafter	0
Minimum future commitments, Total	79
IPL [Member] | Other [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2022	34
Minimum future commitments, 2023	4
Minimum future commitments, 2024	2
Minimum future commitments, 2025	2
Minimum future commitments, 2026	2
Minimum future commitments, Thereafter	23
Minimum future commitments, Total	67
WPL [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2022	223
Minimum future commitments, 2023	108
Minimum future commitments, 2024	69
Minimum future commitments, 2025	51
Minimum future commitments, 2026	47
Minimum future commitments, Thereafter	110
Minimum future commitments, Total	608
WPL [Member] | Natural Gas [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2022	159
Minimum future commitments, 2023	88
Minimum future commitments, 2024	60
Minimum future commitments, 2025	50
Minimum future commitments, 2026	46
Minimum future commitments, Thereafter	110
Minimum future commitments, Total	513
WPL [Member] | Coal [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2022	31
Minimum future commitments, 2023	19
Minimum future commitments, 2024	8
Minimum future commitments, 2025	0
Minimum future commitments, 2026	0
Minimum future commitments, Thereafter	0
Minimum future commitments, Total	58
WPL [Member] | Other [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2022	33
Minimum future commitments, 2023	1
Minimum future commitments, 2024	1
Minimum future commitments, 2025	1
Minimum future commitments, 2026	1
Minimum future commitments, Thereafter	0
Minimum future commitments, Total	$ 37

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Commitments And Contingencies (Schedule Of Environmental Liabilities) (Details) - Natural Gas Processing Plant [Member] $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)
Current and non-current environmental liabilities	$ 11
IPL [Member]
Current and non-current environmental liabilities	8
Minimum [Member]
Range of estimated future costs	8
Minimum [Member] | IPL [Member]
Range of estimated future costs	6
Maximum [Member]
Range of estimated future costs	24
Maximum [Member] | IPL [Member]
Range of estimated future costs	$ 18

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Segments Of Business (Narrative) (Details)	12 Months Ended
	Dec. 31, 2021 segment
Utility Business [Member]
Segment Reporting Information [Line Items]
Number of reportable segments (in segments)	3
IPL [Member]
Segment Reporting Information [Line Items]
Number of reportable segments (in segments)	3
WPL [Member]
Segment Reporting Information [Line Items]
Number of reportable segments (in segments)	3

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Segments Of Business (Schedule Of Segment Of Business) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenues	$ 3,669	$ 3,416	$ 3,648
Depreciation and amortization	657	615	567
Operating income (loss)	795	740	778
Interest expense	277	275	273
Equity income from unconsolidated investments, net	(62)	(61)	(53)
Income tax expense (benefit)	(74)	(57)	69
Net income attributable to common shareowners	659	614	557
Total assets	18,553	17,710	16,701
Investments in equity method subsidiaries	508	476	458
Construction and acquisition expenditures	1,169	1,366	1,640
IPL [Member]
Segment Reporting Information [Line Items]
Revenues	2,063	1,947	2,089
Operating income (loss)	460	410	403
Interest expense	139	139	127
Income tax expense (benefit)	(36)	(47)	24
Net income attributable to common shareowners	350	324	284
Total assets	9,996	9,849
WPL [Member]
Segment Reporting Information [Line Items]
Revenues	1,523	1,395	1,476
Operating income (loss)	308	306	347
Interest expense	105	104	102
Income tax expense (benefit)	(51)	(19)	49
Total assets	7,518	6,912
Electric [Member]
Segment Reporting Information [Line Items]
Revenues	3,081	2,920	3,064
Depreciation and amortization	591	556	513
Operating income (loss)	716	643	679
Equity income from unconsolidated investments, net	(2)	(2)	(1)
Total assets	14,924	14,358	13,659
Investments in equity method subsidiaries	17	11	9
Construction and acquisition expenditures	980	1,109	1,439
Electric [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	1,752	1,695	1,781
Depreciation and amortization	338	321	295
Operating income (loss)	420	358	360
Total assets	8,602	8,518	8,075
Construction and acquisition expenditures	342	626	964
Electric [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	1,329	1,225	1,283
Depreciation and amortization	253	235	218
Operating income (loss)	296	285	319
Total assets	6,322	5,840	5,584
Construction and acquisition expenditures	638	483	475
Gas [Member]
Segment Reporting Information [Line Items]
Revenues	456	373	455
Depreciation and amortization	54	49	47
Operating income (loss)	63	74	70
Equity income from unconsolidated investments, net	0	0	0
Total assets	1,487	1,413	1,269
Investments in equity method subsidiaries	0	0	0
Construction and acquisition expenditures	90	182	100
Gas [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	265	208	264
Depreciation and amortization	31	30	29
Operating income (loss)	43	50	39
Total assets	819	766	734
Construction and acquisition expenditures	42	59	56
Gas [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	191	165	191
Depreciation and amortization	23	19	18
Operating income (loss)	20	24	31
Total assets	668	647	535
Construction and acquisition expenditures	48	123	44
Other Utility [Member]
Segment Reporting Information [Line Items]
Revenues	49	49	46
Depreciation and amortization	6	5	3
Operating income (loss)	(11)	(1)	1
Equity income from unconsolidated investments, net	0	0	0
Total assets	1,103	990	856
Investments in equity method subsidiaries	0	0	0
Construction and acquisition expenditures	0	2	0
Other Utility [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	46	44	44
Depreciation and amortization	6	5	3
Operating income (loss)	(3)	2	4
Total assets	575	565	468
Construction and acquisition expenditures	0	2	0
Other Utility [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	3	5	2
Depreciation and amortization	0	0	0
Operating income (loss)	(8)	(3)	(3)
Total assets	528	425	388
Construction and acquisition expenditures	0	0	0
Utility Business [Member]
Segment Reporting Information [Line Items]
Revenues	3,586	3,342	3,565
Depreciation and amortization	651	610	563
Operating income (loss)	768	716	750
Interest expense	244	243	229
Equity income from unconsolidated investments, net	(2)	(2)	(1)
Income tax expense (benefit)	(87)	(66)	73
Net income attributable to common shareowners	618	573	517
Total assets	17,514	16,761	15,784
Investments in equity method subsidiaries	17	11	9
Construction and acquisition expenditures	1,070	1,293	1,539
Utility Business [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	2,063	1,947	2,089
Depreciation and amortization	375	356	327
Operating income (loss)	460	410	403
Interest expense	139	139	127
Income tax expense (benefit)	(36)	(47)	24
Net income attributable to common shareowners	350	324	284
Total assets	9,996	9,849	9,277
Construction and acquisition expenditures	384	687	1,020
Utility Business [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	1,523	1,395	1,476
Depreciation and amortization	276	254	236
Operating income (loss)	308	306	347
Interest expense	105	104	102
Income tax expense (benefit)	(51)	(19)	49
Net income attributable to common shareowners	268	249	233
Total assets	7,518	6,912	6,507
Construction and acquisition expenditures	686	606	519
Non-Utility [Member]
Segment Reporting Information [Line Items]
Revenues	83	74	83
Depreciation and amortization	6	5	4
Operating income (loss)	27	24	28
Interest expense	33	32	44
Equity income from unconsolidated investments, net	(60)	(59)	(52)
Income tax expense (benefit)	13	9	(4)
Net income attributable to common shareowners	41	41	40
Total assets	1,039	949	917
Investments in equity method subsidiaries	491	465	449
Construction and acquisition expenditures	$ 99	$ 73	$ 101

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Related Parties (Narrative) (Details) - WPL [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021
Related Party Transaction [Line Items]
Receipt of construction deposits	$ 46
WPL Owed ATC [Member]
Related Party Transaction [Line Items]
Net amounts owed	$ 9	$ 10

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Related Parties (Service Agreements) (Details) - Corporate Services [Member] - Subsidiary of Common Parent [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Administrative and General Services Billings [Member] | IPL [Member]
Related Party Transaction [Line Items]
Amounts billed between related parties	$ 180	$ 176	$ 185
Administrative and General Services Billings [Member] | WPL [Member]
Related Party Transaction [Line Items]
Amounts billed between related parties	154	142	142
Transmission Sales Credited [Member] | IPL [Member]
Related Party Transaction [Line Items]
Amounts billed between related parties	22	35	68
Transmission Sales Credited [Member] | WPL [Member]
Related Party Transaction [Line Items]
Amounts billed between related parties	23	3	7
Transmission Purchases Billed [Member] | IPL [Member]
Related Party Transaction [Line Items]
Amounts billed between related parties	441	329	331
Transmission Purchases Billed [Member] | WPL [Member]
Related Party Transaction [Line Items]
Amounts billed between related parties	$ 116	$ 108	$ 120

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Related Parties (Net Intercompany Payables) (Details) - Corporate Services [Member] - Subsidiary of Common Parent [Member] - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
IPL [Member]
Related Party Transaction [Line Items]
Intercompany payables to Corporate Services	$ 110	$ 110
WPL [Member]
Related Party Transaction [Line Items]
Intercompany payables to Corporate Services	$ 83	$ 73

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Related Parties (Related Amounts Billed Between Parties) (Details) - WPL [Member] - ATC LLC [Member] - Equity Method Investment [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
ATC Billings To WPL [Member]
Related Party Transaction [Line Items]
Amounts billed between related parties	$ 122	$ 108	$ 109
WPL Billings To ATC [Member]
Related Party Transaction [Line Items]
Amounts billed between related parties	$ 18	$ 10	$ 13

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Condensed Parent Company Financial Statements (Condensed Statements Of Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating expenses	$ 2,874	$ 2,676	$ 2,870
Operating income (loss)	795	740	778
Other (income) and deductions:
Equity earnings from consolidated subsidiaries	(62)	(61)	(53)
Interest expense	277	275	273
Total other (income) and deductions	195	173	142
Income before income taxes	600	567	636
Income tax benefit	(74)	(57)	69
Net income	674	624	567
Parent Company [Member]
Operating expenses	5	7	2
Operating income (loss)	(5)	(7)	(2)
Other (income) and deductions:
Equity earnings from consolidated subsidiaries	(664)	(625)	(562)
Interest expense	1	2	9
Other	1	4	7
Total other (income) and deductions	(662)	(619)	(546)
Income before income taxes	657	612	544
Income tax benefit	(5)	(4)	(15)
Net income	$ 662	$ 616	$ 559

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Condensed Parent Company Financial Statements (Condensed Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Other	$ 240	$ 123
Total current assets	1,069	887
Investments:
Other	179	154
Total investments	517	485
Other assets	1,980	2,002
Total assets	18,553	17,710	$ 16,701
Current liabilities:
Commercial paper	515	389
Other	226	207
Total current liabilities	2,054	1,297
Other liabilities	388	374
Common Equity:
Retained earnings	3,250	2,994
Shares in deferred compensation trust	(12)	(11)
Total common equity	5,990	5,688
Total liabilities and equity	18,553	17,710
Parent Company [Member]
Current assets:
Notes receivable from affiliated companies	16	32
Other	5	5
Total current assets	21	37
Investments:
Investments in consolidated subsidiaries	7,061	6,664
Other	2	2
Total investments	7,063	6,666
Other assets	96	88
Total assets	7,180	6,791
Current liabilities:
Commercial paper	279	132
Notes payable to affiliated companies	900	937
Other	4	29
Total current liabilities	1,183	1,098
Other liabilities	2	2
Common Equity:
Common stock and additional paid-in capital	2,752	2,706
Retained earnings	3,255	2,996
Shares in deferred compensation trust	(12)	(11)
Total common equity	5,995	5,691
Total liabilities and equity	$ 7,180	$ 6,791

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Condensed Parent Company Financial Statements (Condensed Statements of Cash Flows) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net cash flows from operating activities	$ 582.0	$ 501.0	$ 660.0
Cash flows from (used for) investing activities:
Dividends from consolidated subsidiaries in excess of equity earnings	(61.0)	(43.0)	(60.0)
Net cash flows from (used for) investing activities	(728.0)	(951.0)	(1,287.0)
Cash flows used for financing activities:
Common stock dividends	(403.0)	(377.0)	(337.0)
Proceeds from issuance of common stock, net	28.0	247.0	390.0
Net change in commercial paper	126.0	52.0	(104.0)
Other	(13.0)	(27.0)	(24.0)
Net cash flows from (used for) financing activities	130.0	488.0	619.0
Net increase (decrease) in cash, cash equivalents and restricted cash	(16.0)	38.0	(8.0)
Cash, cash equivalents and restricted cash at beginning of period	56.0	18.0	26.0
Cash, cash equivalents and restricted cash at end of period	40.0	56.0	18.0
Supplemental cash flows information:
Interest	(272.0)	(274.0)	(268.0)
Income taxes, net	(3.0)	5.0	21.0
Parent Company [Member]
Net cash flows from operating activities	494.0	396.0	305.0
Cash flows from (used for) investing activities:
Capital contributions to consolidated subsidiaries	(295.0)	(429.0)	(250.0)
Net change in notes receivable from and payable to affiliates	(21.0)	201.0	8.0
Dividends from consolidated subsidiaries in excess of equity earnings	50.0	0.0	0.0
Net cash flows from (used for) investing activities	(266.0)	(228.0)	(242.0)
Cash flows used for financing activities:
Common stock dividends	(403.0)	(377.0)	(338.0)
Proceeds from issuance of common stock, net	28.0	247.0	390.0
Net change in commercial paper	147.0	(37.0)	(116.0)
Other	0.0	(1.0)	1.0
Net cash flows from (used for) financing activities	(228.0)	(168.0)	(63.0)
Net increase (decrease) in cash, cash equivalents and restricted cash	0.0	0.0	0.0
Cash, cash equivalents and restricted cash at beginning of period	0.0	0.0	0.0
Cash, cash equivalents and restricted cash at end of period	0.0	0.0	0.0
Supplemental cash flows information:
Interest	(1.0)	(2.0)	(9.0)
Income taxes, net	$ 4.0	$ 10.0	$ 14.0

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Valuation And Qualifying Accounts and Reserves (Details) - Accumulated Provision for Uncollectible Accounts [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	$ 18.0	$ 7.0	$ 10.0
Charged to Expense	12.0	25.0	17.0
Charged to Other Accounts	0.0	9.0	2.0
Deductions	19.0	23.0	22.0
Ending Balance	11.0	18.0	7.0
IPL [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	1.0	1.0	3.0
Charged to Expense	6.0	18.0	16.0
Charged to Other Accounts	0.0	0.0	0.0
Deductions	6.0	18.0	18.0
Ending Balance	1.0	1.0	1.0
WPL [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	17.0	6.0	7.0
Charged to Expense	6.0	7.0	1.0
Charged to Other Accounts	0.0	9.0	2.0
Deductions	13.0	5.0	4.0
Ending Balance	$ 10.0	$ 17.0	$ 6.0