10-Q

Table of Contents

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-Q

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

For the quarterly period ended June 30, 2023

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-Q is separately filed by Alliant Energy Corporation, Interstate Power and Light Company and Wisconsin Power and Light Company. Information contained in the Form 10-Q 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

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 registrant was 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, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an 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 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 ☒

Number of shares outstanding of each class of common stock as of June 30, 2023:

Alliant Energy Corporation, Common Stock, $0.01 par value, 252,719,092 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)

Table of Contents

TABLE OF CONTENTS

	Page
Definitions	1
Forward-looking Statements	1
Part I. Financial Information	3
Item 1. Condensed Consolidated Financial Statements (Unaudited)	3
Alliant Energy Corporation	3
Interstate Power and Light Company	6
Wisconsin Power and Light Company	9
Combined Notes to Condensed Consolidated Financial Statements	12
1. Summary of Significant Accounting Policies	12
2. Regulatory Matters	12
3. Property, Plant and Equipment	13
4. Receivables	13
5. Investments	14
6. Common Equity	14
7. Debt	16
8. Revenues	18
9. Income Taxes	18
10. Benefit Plans	19
11. Derivative Instruments	20
12. Fair Value Measurements	21
13. Commitments and Contingencies	23
14. Segments of Business	25
15. Related Parties	26
Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations	27
Item 3. Quantitative and Qualitative Disclosures About Market Risk	35
Item 4. Controls and Procedures	35
Part II. Other Information	35
Item 1. Legal Proceedings	35
Item 1A. Risk Factors	35
Item 2. Unregistered Sales of Equity Securities and Use of Proceeds	35
Item 5. Other Information	35
Item 6. Exhibits	36
Signatures	36

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DEFINITIONS

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

Abbreviation or Acronym	Definition	Abbreviation or Acronym	Definition
2022 Form 10-K	Combined Annual Report on Form 10-K filed by Alliant Energy, IPL and WPL for the year ended Dec. 31, 2022	IUB	Iowa Utilities Board
AEF	Alliant Energy Finance, LLC	MDA	Management’s Discussion and Analysis of Financial Condition and Results of Operations
AFUDC	Allowance for funds used during construction	MISO	Midcontinent Independent System Operator, Inc.
Alliant Energy	Alliant Energy Corporation	MW	Megawatt
ATC	American Transmission Company LLC	MWh	Megawatt-hour
ATC Holdings	Interest in American Transmission Company LLC and ATC Holdco LLC	N/A	Not applicable
Corporate Services	Alliant Energy Corporate Services, Inc.	Note(s)	Combined Notes to Condensed Consolidated Financial Statements
Dth	Dekatherm	OPEB	Other postretirement benefits
EGU	Electric generating unit	PPA	Purchased power agreement
EPA	U.S. Environmental Protection Agency	PSCW	Public Service Commission of Wisconsin
EPS	Earnings per weighted average common share	SEC	Securities and Exchange Commission
Financial Statements	Condensed Consolidated Financial Statements	U.S.	United States of America
FTR	Financial transmission right	West Riverside	West Riverside Energy Center and Solar Facility
GAAP	U.S. generally accepted accounting principles	Whiting Petroleum	Whiting Petroleum Corporation
IPL	Interstate Power and Light Company	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 direct or indirect effects resulting from cyber security incidents or attacks on Alliant Energy’s, IPL’s or WPL’s physical infrastructure, 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;

•inflation and higher interest rates;

•changes in the price of delivered natural gas, transmission, purchased electricity and delivered coal, particularly during elevated market prices, and any resulting changes to counterparty credit risk, due to shifts in supply and demand caused by market conditions, regulations and MISO’s seasonal resource adequacy process;

•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, capacity costs, deferred expenditures, deferred tax assets, tax expense, interest 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;

•the ability to obtain regulatory approval for construction projects with acceptable conditions;

•the ability to complete construction of renewable generation and storage projects by planned in-service dates and within the cost targets set by regulators due to cost increases of and access to materials, equipment and commodities, which could result from tariffs, duties or other assessments, such as any additional tariffs resulting from U.S. Department of Commerce investigations into and any decisions made regarding the sourcing of solar project materials and equipment from certain countries, 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;

•the ability to utilize tax credits generated to date, and those that may be generated in the future, before they expire, as well as the ability to transfer tax credits that may be generated in the future at adequate pricing;

•disruptions to ongoing operations and the supply of materials, services, equipment and commodities needed to construct solar generation, battery storage and electric and gas distribution projects, which may result from geopolitical issues, supplier manufacturing constraints, labor issues or transportation issues, and thus affect the ability to meet capacity requirements and result in increased capacity expense;

•the future development of technologies related to electrification, and the ability to reliably store and manage electricity;

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

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

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

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

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

•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;

•impacts that terrorist attacks 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;

•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;

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

•changes to MISO’s resource adequacy process establishing capacity planning reserve margin and capacity accreditation requirements that may impact how and when new and existing generating facilities, including 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, to add resources to meet the requirements of MISO’s process, or procure capacity in the market whereby such costs might not be recovered in rates;

•issues associated with environmental remediation and environmental compliance, including compliance with all environmental and emissions permits and future changes in environmental laws and regulations, including changes to the Coal Combustion Residuals Rule, Cross-State Air Pollution Rule emissions allowances and federal, state or local regulations for greenhouse gases emissions reductions from new and existing fossil-fueled EGUs under the Clean Air Act, and litigation associated with environmental requirements;

•increased pressure from customers, investors and other stakeholders to more rapidly reduce greenhouse gases 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;

•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 and successful resolution of warranty issues or contract disputes 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 operating, fuel-related and capital 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 construction activities, and recovery of costs associated with restoration activities, or on the operations of Alliant Energy’s investments;

•the direct or indirect effects resulting from the ongoing novel coronavirus (COVID-19) pandemic and the spread of variant strains;

•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, including settlement losses related to pension plans;

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

•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 changes in valuations of the assets held, as well as 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;

•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 Risk Factors in Item 1A in the 2022 Form 10-K.

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.

Available Information. Alliant Energy routinely posts important information on its website and considers the Investors section of its website, www.alliantenergy.com/investors, a channel of distribution for material information. Information contained on Alliant Energy’s website is not incorporated herein.

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PART I. FINANCIAL INFORMATION

ITEM 1. CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED)

ALLIANT ENERGY CORPORATION

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

	For the Three Months		For the Six Months
	Ended June 30,		Ended June 30,
	2023	2022	2023	2022
	(in millions, except per share amounts)
Revenues:
Electric utility	$799	$812	$1,567	$1,586
Gas utility	77	94	353	356
Other utility	13	13	25	23
Non-utility	23	24	45	47
Total revenues	912	943	1,990	2,012
Operating expenses:
Electric production fuel and purchased power	166	191	322	359
Electric transmission service	138	133	284	271
Cost of gas sold	33	48	215	216
Other operation and maintenance	163	166	338	320
Depreciation and amortization	167	166	333	332
Taxes other than income taxes	28	27	59	54
Total operating expenses	695	731	1,551	1,552
Operating income	217	212	439	460
Other (income) and deductions:
Interest expense	96	78	190	152
Equity income from unconsolidated investments, net	(14)	(16)	(31)	(32)
Allowance for funds used during construction	(24)	(13)	(43)	(24)
Other	(1)	—	2	1
Total other (income) and deductions	57	49	118	97
Income before income taxes	160	163	321	363
Income tax expense (benefit)	—	4	(2)	12
Net income attributable to Alliant Energy common shareowners	$160	$159	$323	$351
Weighted average number of common shares outstanding:
Basic	251.7	250.9	251.4	250.7
Diluted	251.9	251.1	251.6	251.0
Earnings per weighted average common share attributable to Alliant Energy common shareowners (basic and diluted)	$0.64	$0.63	$1.28	$1.40

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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ALLIANT ENERGY CORPORATION

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)

	June 30, 2023	December 31, 2022
	(in millions, except per share and share amounts)
ASSETS
Current assets:
Cash and cash equivalents	$13	$20
Accounts receivable, less allowance for expected credit losses	428	516
Production fuel, at weighted average cost	64	53
Gas stored underground, at weighted average cost	69	132
Materials and supplies, at weighted average cost	172	140
Regulatory assets	196	166
Other	196	223
Total current assets	1,138	1,250
Property, plant and equipment, net	16,306	16,247
Investments:
ATC Holdings	372	358
Other	212	201
Total investments	584	559
Other assets:
Regulatory assets	2,148	1,880
Deferred charges and other	207	227
Total other assets	2,355	2,107
Total assets	$20,383	$20,163

LIABILITIES AND EQUITY
Current liabilities:
Current maturities of long-term debt	$409	$408
Commercial paper	391	642
Other short-term borrowings	50	—
Accounts payable	585	756
Regulatory liabilities	121	206
Other	337	351
Total current liabilities	1,893	2,363
Long-term debt, net (excluding current portion)	8,186	7,668
Other liabilities:
Deferred tax liabilities	1,969	1,943
Regulatory liabilities	1,087	1,118
Pension and other benefit obligations	262	277
Other	534	518
Total other liabilities	3,852	3,856
Commitments and contingencies (Note 13)
Equity:
Alliant Energy Corporation common equity:
Common stock - $0.01 par value - 480,000,000 shares authorized; 252,719,092 and 251,134,966 shares outstanding	3	3
Additional paid-in capital	2,854	2,777
Retained earnings	3,606	3,509
Accumulated other comprehensive income	3	—
Shares in deferred compensation trust - 405,051 and 402,134 shares at a weighted average cost of $33.69 and $32.63 per share	(14)	(13)
Total Alliant Energy Corporation common equity	6,452	6,276
Total liabilities and equity	$20,383	$20,163

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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ALLIANT ENERGY CORPORATION

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

	For the Six Months
	Ended June 30,
	2023	2022
	(in millions)
Cash flows from operating activities:
Net income	$323	$351
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	333	332
Equity component of allowance for funds used during construction	(32)	(18)
Other	14	14
Other changes in assets and liabilities:
Accounts receivable	(186)	(283)
Gas stored underground	63	17
Derivative assets	86	(183)
Regulatory assets	(36)	(116)
Accounts payable	(84)	95
Derivative liabilities	18	86
Regulatory liabilities	(116)	74
Deferred income taxes	24	34
Other	(96)	(103)
Net cash flows from operating activities	311	300
Cash flows used for investing activities:
Construction and acquisition expenditures:
Utility business	(758)	(550)
Other	(62)	(43)
Cash receipts on sold receivables	272	233
Proceeds from sales of partial ownership interest in West Riverside	120	—
Other	(54)	(10)
Net cash flows used for investing activities	(482)	(370)
Cash flows from financing activities:
Common stock dividends	(226)	(215)
Proceeds from issuance of common stock, net	76	13
Proceeds from issuance of long-term debt	862	650
Payments to retire long-term debt	(404)	(304)
Net change in commercial paper and other short-term borrowings	(146)	(116)
Contributions from noncontrolling interest	—	29
Other	(1)	(7)
Net cash flows from financing activities	161	50
Net decrease in cash, cash equivalents and restricted cash	(10)	(20)
Cash, cash equivalents and restricted cash at beginning of period	24	40
Cash, cash equivalents and restricted cash at end of period	$14	$20
Supplemental cash flows information:
Cash (paid) refunded during the period for:
Interest	($179)	($146)
Income taxes, net	$3	($4)
Significant non-cash investing and financing activities:
Accrued capital expenditures	$300	$200
Beneficial interest obtained in exchange for securitized accounts receivable	$175	$244

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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INTERSTATE POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

	For the Three Months		For the Six Months
	Ended June 30,		Ended June 30,
	2023	2022	2023	2022
	(in millions)
Revenues:
Electric utility	$431	$442	$819	$843
Gas utility	44	52	194	191
Steam and other	12	12	24	22
Total revenues	487	506	1,037	1,056
Operating expenses:
Electric production fuel and purchased power	66	83	113	150
Electric transmission service	96	91	201	188
Cost of gas sold	20	27	116	112
Other operation and maintenance	85	87	181	171
Depreciation and amortization	96	95	191	189
Taxes other than income taxes	14	14	29	28
Total operating expenses	377	397	831	838
Operating income	110	109	206	218
Other (income) and deductions:
Interest expense	37	37	74	74
Allowance for funds used during construction	(4)	(3)	(8)	(5)
Other	1	—	3	(1)
Total other (income) and deductions	34	34	69	68
Income before income taxes	76	75	137	150
Income tax benefit	(13)	(12)	(24)	(23)
Net income	$89	$87	$161	$173

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 Condensed Consolidated Financial Statements.

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INTERSTATE POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)

	June 30, 2023	December 31, 2022
	(in millions, except per share and share amounts)
ASSETS
Current assets:
Cash and cash equivalents	$9	$15
Accounts receivable, less allowance for expected credit losses	204	259
Production fuel, at weighted average cost	31	23
Gas stored underground, at weighted average cost	27	60
Materials and supplies, at weighted average cost	100	83
Regulatory assets	90	85
Other	78	93
Total current assets	539	618
Property, plant and equipment, net	7,923	8,046
Other assets:
Regulatory assets	1,558	1,301
Deferred charges and other	101	110
Total other assets	1,659	1,411
Total assets	$10,121	$10,075

LIABILITIES AND EQUITY
Current liabilities:
Accounts payable	$247	$239
Accounts payable to associated companies	40	28
Accrued taxes	51	52
Accrued interest	35	35
Regulatory liabilities	73	114
Other	97	113
Total current liabilities	543	581
Long-term debt, net	3,702	3,646
Other liabilities:
Deferred tax liabilities	1,061	1,047
Regulatory liabilities	603	640
Pension and other benefit obligations	60	62
Other	283	291
Total other liabilities	2,007	2,040
Commitments and contingencies (Note 13)
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	2,847	2,807
Retained earnings	989	968
Total Interstate Power and Light Company common equity	3,869	3,808
Total liabilities and equity	$10,121	$10,075

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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INTERSTATE POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

	For the Six Months
	Ended June 30,
	2023	2022
	(in millions)
Cash flows from operating activities:
Net income	$161	$173
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	191	189
Other	2	(9)
Other changes in assets and liabilities:
Accounts receivable	(216)	(256)
Gas stored underground	33	12
Derivative assets	43	(123)
Regulatory assets	(2)	(52)
Accounts payable	(32)	67
Derivative liabilities	(9)	63
Regulatory liabilities	(78)	53
Deferred income taxes	8	24
Other	(49)	(58)
Net cash flows from operating activities	52	83
Cash flows from (used for) investing activities:
Construction and acquisition expenditures	(251)	(172)
Cash receipts on sold receivables	272	233
Other	(36)	(1)
Net cash flows from (used for) investing activities	(15)	60
Cash flows used for financing activities:
Common stock dividends	(140)	(160)
Capital contributions from parent	40	—
Net change in commercial paper	55	—
Other	2	(4)
Net cash flows used for financing activities	(43)	(164)
Net decrease in cash, cash equivalents and restricted cash	(6)	(21)
Cash, cash equivalents and restricted cash at beginning of period	15	34
Cash, cash equivalents and restricted cash at end of period	$9	$13
Supplemental cash flows information:
Cash (paid) refunded during the period for:
Interest	($74)	($74)
Income taxes, net	$25	$19
Significant non-cash investing and financing activities:
Accrued capital expenditures	$95	$45
Beneficial interest obtained in exchange for securitized accounts receivable	$175	$244

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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WISCONSIN POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

	For the Three Months		For the Six Months
	Ended June 30,		Ended June 30,
	2023	2022	2023	2022
	(in millions)
Revenues:
Electric utility	$368	$370	$748	$743
Gas utility	33	42	159	165
Other	1	1	1	1
Total revenues	402	413	908	909
Operating expenses:
Electric production fuel and purchased power	99	108	209	209
Electric transmission service	42	41	83	83
Cost of gas sold	13	21	99	104
Other operation and maintenance	67	67	133	123
Depreciation and amortization	69	69	137	139
Taxes other than income taxes	13	12	27	24
Total operating expenses	303	318	688	682
Operating income	99	95	220	227
Other (income) and deductions:
Interest expense	36	28	72	55
Allowance for funds used during construction	(19)	(10)	(35)	(18)
Other	(4)	—	(3)	—
Total other (income) and deductions	13	18	34	37
Income before income taxes	86	77	186	190
Income tax expense	14	14	26	34
Net income	$72	$63	$160	$156

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 Condensed Consolidated Financial Statements.

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WISCONSIN POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)

	June 30, 2023	December 31, 2022
	(in millions, except per share and share amounts)
ASSETS
Current assets:
Cash and cash equivalents	$3	$5
Accounts receivable, less allowance for expected credit losses	210	244
Production fuel, at weighted average cost	33	29
Gas stored underground, at weighted average cost	42	73
Materials and supplies, at weighted average cost	70	54
Regulatory assets	106	81
Prepaid gross receipts tax	47	42
Other	47	60
Total current assets	558	588
Property, plant and equipment, net	7,882	7,722
Other assets:
Regulatory assets	590	579
Deferred charges and other	69	98
Total other assets	659	677
Total assets	$9,099	$8,987

LIABILITIES AND EQUITY
Current liabilities:
Commercial paper	$44	$290
Accounts payable	277	456
Regulatory liabilities	48	92
Other	140	111
Total current liabilities	509	949
Long-term debt, net	3,068	2,770
Other liabilities:
Deferred tax liabilities	785	789
Regulatory liabilities	484	478
Pension and other benefit obligations	127	140
Other	387	370
Total other liabilities	1,783	1,777
Commitments and contingencies (Note 13)
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	2,413	2,233
Retained earnings	1,260	1,192
Total Wisconsin Power and Light Company common equity	3,739	3,491
Total liabilities and equity	$9,099	$8,987

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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WISCONSIN POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

	For the Six Months
	Ended June 30,
	2023	2022
	(in millions)
Cash flows from operating activities:
Net income	$160	$156
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	137	139
Equity component of allowance for funds used during construction	(26)	(14)
Other	(4)	18
Other changes in assets and liabilities:
Accounts receivable	33	(17)
Gas stored underground	31	5
Derivative assets	47	(60)
Regulatory assets	(35)	(65)
Accounts payable	(54)	38
Derivative liabilities	27	23
Regulatory liabilities	(38)	20
Other	(10)	(45)
Net cash flows from operating activities	268	198
Cash flows used for investing activities:
Construction and acquisition expenditures	(507)	(378)
Proceeds from sales of partial ownership interest in West Riverside	120	—
Other	(15)	(6)
Net cash flows used for investing activities	(402)	(384)
Cash flows from financing activities:
Common stock dividends	(92)	(89)
Capital contributions from parent	180	265
Proceeds from issuance of long-term debt	297	—
Net change in commercial paper	(246)	(14)
Contributions from noncontrolling interest	—	29
Other	(7)	(3)
Net cash flows from financing activities	132	188
Net increase (decrease) in cash, cash equivalents and restricted cash	(2)	2
Cash, cash equivalents and restricted cash at beginning of period	5	2
Cash, cash equivalents and restricted cash at end of period	$3	$4
Supplemental cash flows information:
Cash paid during the period for:
Interest	($69)	($54)
Income taxes, net	($42)	($31)
Significant non-cash investing and financing activities:
Accrued capital expenditures	$196	$150

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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ALLIANT ENERGY CORPORATION

INTERSTATE POWER AND LIGHT COMPANY

WISCONSIN POWER AND LIGHT COMPANY

COMBINED NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED)

NOTE 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

NOTE 1(a) General - The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the SEC. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the 2022 Form 10-K.

In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the six months ended June 30, 2023 are not necessarily indicative of results that may be expected for the year ending December 31, 2023.

A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred. Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.

NOTE 2. REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

Regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$957	$929	$868	$848	$89	$81
Pension and OPEB costs	378	392	190	197	188	195
Assets retired early	290	70	274	53	16	17
Asset retirement obligations	197	151	156	110	41	41
Commodity cost recovery	145	160	6	1	139	159
Derivatives	102	84	41	48	61	36
IPL’s Duane Arnold Energy Center PPA amendment	54	66	54	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	47	48	—	—	47	48
Other	174	146	59	63	115	83
	$2,344	$2,046	$1,648	$1,386	$696	$660

Assets retired early - In May 2023, IPL retired the coal-fired Lansing Generating Station and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and IPL’s balance sheets. The related regulatory asset balance as of June 30, 2023 was $226 million, which is currently included in IPL’s rate base and IPL is earning a return of and a return on the remaining balance. Continued recovery of the remaining net book value of Lansing is expected to be addressed in future IPL rate reviews.

Derivatives - Refer to Note 11 for discussion of changes in Alliant Energy’s, IPL’s and WPL’s derivative liabilities/assets during the six months ended June 30, 2023, which resulted in comparable changes to regulatory assets/liabilities on the balance sheets.

Regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$572	$579	$301	$303	$271	$276
Cost of removal obligations	405	398	260	259	145	139
Derivatives	90	210	48	115	42	95
Commodity cost recovery	39	40	15	38	24	2
Electric transmission cost recovery	19	20	14	10	5	10
WPL’s West Riverside liquidated damages	17	32	—	—	17	32
Other	66	45	38	29	28	16
	$1,208	$1,324	$676	$754	$532	$570

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WPL’s West Riverside liquidated damages - Pursuant to PSCW authorization, WPL’s amortization of liquidated damages related to West Riverside construction procurement contracts was used to offset increases in WPL’s retail electric 2022/2023 Test Period revenue requirement, which resulted in decreases in regulatory liabilities on Alliant Energy’s and WPL’s balance sheets and decreases in depreciation and amortization expenses in Alliant Energy’s and WPL’s income statements for the three and six months ended June 30, 2023.

NOTE 3. PROPERTY, PLANT AND EQUIPMENT

In March 2023 and June 2023, Madison Gas and Electric Company and WEC Energy Group, Inc., respectively, acquired partial ownership interests in West Riverside. The related proceeds are included in “Proceeds from sales of partial ownership interest in West Riverside” in investing activities in Alliant Energy’s and WPL’s cash flows statements for the six months ended June 30, 2023. As a result of these transactions, WPL’s undivided current ownership interest in West Riverside is 73.8%.

NOTE 4. RECEIVABLES

NOTE 4(a) - Accounts Receivable - For the three and six months ended June 30, 2023, Alliant Energy’s, IPL’s and WPL’s gross write-offs for accounts receivable were as follows (in millions):

	Originated in 2022		Originated in 2023
	Three Months	Six Months	Three Months	Six Months
Alliant Energy	$3	$8	$2	$2
IPL	2	5	1	1
WPL	1	3	1	1

NOTE 4(b) - Sales of Accounts Receivable - IPL maintains a Receivables Purchase and Sale Agreement (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 March 2023, IPL amended and extended through March 2024 the purchase commitment from the third party to which it sells its receivables. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. As of June 30, 2023, IPL had $50 million of available capacity under its sales of accounts receivable program. IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and six months ended June 30 were as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
Maximum outstanding aggregate cash proceeds	$110	$66	$110	$66
Average outstanding aggregate cash proceeds	101	18	79	11

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

	June 30, 2023	December 31, 2022
Customer accounts receivable	$148	$145
Unbilled utility revenues	100	132
Receivables sold to third party	248	277
Less: cash proceeds	60	80
Deferred proceeds	188	197
Less: allowance for expected credit losses	13	12
Fair value of deferred proceeds	$175	$185

As of June 30, 2023, outstanding receivables past due under the Receivables Agreement were $20 million. Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and six months ended June 30 were as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
Collections	$514	$500	$1,104	$1,061
Write-offs, net of recoveries	2	1	4	3

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NOTE 5. INVESTMENTS

Unconsolidated Equity Investments - Alliant Energy’s equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three and six months ended June 30 was as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
ATC Holdings	($12)	($11)	($25)	($23)
Other	(2)	(5)	(6)	(9)
	($14)	($16)	($31)	($32)

NOTE 6. COMMON EQUITY

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

Shares outstanding, January 1, 2023	251,134,966
At-the-market offering program	1,221,775
Shareowner Direct Plan	228,017
Equity-based compensation plans	134,334
Shares outstanding, June 30, 2023	252,719,092

At-the-Market Offering Program - In December 2022, Alliant Energy filed a prospectus supplement under which it may sell up to $225 million of its common stock through an at-the-market offering program. As of June 30, 2023, Alliant Energy issued 1,221,775 shares of common stock through this program and received cash proceeds of $64 million, net of $1 million in commissions and fees. Alliant Energy also had commitments not recognized on its balance sheet at June 30, 2023 to sell 172,701 shares of common stock under sales transactions executed through this program in late June 2023. Subsequent to June 30, 2023, Alliant Energy issued shares to settle these transactions in exchange for net cash proceeds of $9 million. The proceeds from the issuances of common stock were used for general corporate purposes.

Changes in Shareowners’ Equity - A summary of changes in shareowners’ equity was as follows (in millions):

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in
		Additional		Other	Deferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Noncontrolling	Total
	Stock	Capital	Earnings	Income (Loss)	Trust	Interest	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$3	$2,780	$3,559	($1)	($13)	$—	$6,328
Net income attributable to Alliant Energy common shareowners			160				160
Common stock dividends ($0.4525 per share)			(113)				(113)
At-the-market offering program and Shareowner Direct Plan issuances		70					70
Equity-based compensation plans and other		4			(1)		3
Other comprehensive income, net of tax				4			4
Ending balance, June 30, 2023	$3	$2,854	$3,606	$3	($14)	$—	$6,452
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$3	$2,750	$3,336	$—	($12)	$—	$6,077
Net income attributable to Alliant Energy common shareowners			159				159
Common stock dividends ($0.4275 per share)			(108)				(108)
Shareowner Direct Plan issuances		6					6
Equity-based compensation plans and other		3					3
Contributions from noncontrolling interest						29	29
Ending balance, June 30, 2022	$3	$2,759	$3,387	$—	($12)	$29	$6,166

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Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in
		Additional		Other	Deferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Noncontrolling	Total
	Stock	Capital	Earnings	Income (Loss)	Trust	Interest	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$3	$2,777	$3,509	$—	($13)	$—	$6,276
Net income attributable to Alliant Energy common shareowners			323				323
Common stock dividends ($0.905 per share)			(226)				(226)
At-the-market offering program and Shareowner Direct Plan issuances		76					76
Equity-based compensation plans and other		1			(1)		—
Other comprehensive income, net of tax				3			3
Ending balance, June 30, 2023	$3	$2,854	$3,606	$3	($14)	$—	$6,452
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$3	$2,749	$3,250	$—	($12)	$—	$5,990
Net income attributable to Alliant Energy common shareowners			351				351
Common stock dividends ($0.855 per share)			(215)				(215)
Shareowner Direct Plan issuances		13					13
Equity-based compensation plans and other		(3)	1				(2)
Contributions from noncontrolling interest						29	29
Ending balance, June 30, 2022	$3	$2,759	$3,387	$—	($12)	$29	$6,166

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$33	$2,807	$970	$3,810
Net income			89	89
Common stock dividends			(70)	(70)
Capital contributions from parent		40		40
Ending balance, June 30, 2023	$33	$2,847	$989	$3,869
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$33	$2,807	$935	$3,775
Net income			87	87
Common stock dividends			(80)	(80)
Ending balance, June 30, 2022	$33	$2,807	$942	$3,782

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$33	$2,807	$968	$3,808
Net income			161	161
Common stock dividends			(140)	(140)
Capital contributions from parent		40		40
Ending balance, June 30, 2023	$33	$2,847	$989	$3,869
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$33	$2,807	$929	$3,769
Net income			173	173
Common stock dividends			(160)	(160)
Ending balance, June 30, 2022	$33	$2,807	$942	$3,782

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WPL	Total WPL Common Equity
		Additional
	Common	Paid-In	Retained	Noncontrolling	Total
	Stock	Capital	Earnings	Interest	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$66	$2,413	$1,234	$—	$3,713
Net income			72		72
Common stock dividends			(46)		(46)
Ending balance, June 30, 2023	$66	$2,413	$1,260	$—	$3,739
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$66	$1,884	$1,101	$—	$3,051
Net income			63		63
Common stock dividends			(44)		(44)
Capital contributions from parent		85			85
Contributions from noncontrolling interest				29	29
Other		(1)			(1)
Ending balance, June 30, 2022	$66	$1,968	$1,120	$29	$3,183

WPL	Total WPL Common Equity
		Additional
	Common	Paid-In	Retained	Noncontrolling	Total
	Stock	Capital	Earnings	Interest	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$66	$2,233	$1,192	$—	$3,491
Net income			160		160
Common stock dividends			(92)		(92)
Capital contributions from parent		180			180
Ending balance, June 30, 2023	$66	$2,413	$1,260	$—	$3,739
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$66	$1,704	$1,053	$—	$2,823
Net income			156		156
Common stock dividends			(89)		(89)
Capital contributions from parent		265			265
Contributions from noncontrolling interest				29	29
Other		(1)			(1)
Ending balance, June 30, 2022	$66	$1,968	$1,120	$29	$3,183

NOTE 7. DEBT

NOTE 7(a) Short-term Debt - In March 2023, Alliant Energy, IPL and WPL extended their single credit facility agreement, which currently expires in December 2027, and reallocated credit facility capacity amounts to $450 million for Alliant Energy at the parent company level, $250 million for IPL and $300 million for WPL, within the $1 billion total commitment. Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions):

June 30, 2023	Alliant Energy	IPL	WPL
Amount outstanding	$391	$—	$44
Weighted average interest rates	5.3%	—%	5.2%
Available credit facility capacity (a)	$554	$195	$256

	Alliant Energy		IPL		WPL
Three Months Ended June 30	2023	2022	2023	2022	2023	2022
Maximum amount outstanding (based on daily outstanding balances)	$391	$441	$70	$—	$91	$222
Average amount outstanding (based on daily outstanding balances)	$88	$337	$6	$—	$18	$166
Weighted average interest rates	5.3%	1.0%	5.3%	—%	5.2%	0.9%
Six Months Ended June 30
Maximum amount outstanding (based on daily outstanding balances)	$793	$577	$70	$—	$349	$252
Average amount outstanding (based on daily outstanding balances)	$330	$390	$3	$—	$160	$185
Weighted average interest rates	4.8%	0.6%	5.3%	—%	4.8%	0.5%

(a)Alliant Energy’s and IPL’s available credit facility capacities reflect outstanding commercial paper classified as both short- and long-term debt at June 30, 2023.

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In January 2023, AEF received $50 million of proceeds from its December 2022 term loan credit agreement, which was classified as “Other short-term borrowings” on Alliant Energy’s balance sheet as of June 30, 2023.

NOTE 7(b) Long-term Debt - In June 2023, AEF retired its $400 million 3.75% senior notes. In March 2023, WPL issued $300 million of 4.95% debentures due 2033. WPL’s debentures were issued as green bonds, and an amount equal to or in excess of the net proceeds will be allocated or disbursed for the development and acquisition of its solar EGUs.

As of June 30, 2023, $55 million of commercial paper was recorded in “Long-term debt, net” on Alliant Energy’s and IPL’s balance sheets due to the existence of the long-term single credit facility that back-stops this commercial paper balance, along with Alliant Energy’s and IPL’s intent and ability to refinance these balances on a long-term basis. As of June 30, 2023, this commercial paper balance had a 5% interest rate.

Convertible Senior Notes - In March 2023, Alliant Energy issued $575 million of 3.875% convertible senior notes (the Notes), which are senior unsecured obligations, and used the net proceeds from the issuance for general corporate purposes. The Notes will mature on March 15, 2026 unless earlier converted or repurchased, and no sinking fund is provided for the Notes. Alliant Energy may not redeem the Notes prior to the maturity date. Holders may convert their Notes at their option at any time prior to the close of business on the business day immediately preceding December 15, 2025 only under the following circumstances:

•during any calendar quarter commencing after the calendar quarter ending on June 30, 2023 (and only during such calendar quarter), if the last reported sale price of Alliant Energy’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day during such period;

•during the 5 business day period after any 10 consecutive trading day period (the “measurement period”) in which the trading price (as defined in the related Indenture) per $1,000 principal amount of Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of Alliant Energy’s common stock and the conversion rate on each such trading day; or

•upon the occurrence of specified corporate events.

On or after December 15, 2025 until the close of business on the business day immediately preceding the maturity date, holders may convert all or any portion of their Notes at any time, regardless of the foregoing circumstances. Upon conversion of the Notes, Alliant Energy will pay cash up to the aggregate principal amount of the Notes to be converted and pay or deliver, as the case may be, cash, shares of its common stock or a combination of cash and shares of its common stock, at its election, in respect of the remainder, if any, of its conversion obligation in excess of the aggregate principal amount of the Notes being converted.

The initial conversion rate is 15.5461 shares of common stock per $1,000 principal amount of Notes (equivalent to an initial conversion price of approximately $64.32 per share of Alliant Energy’s common stock). The conversion rate is subject to adjustment in some events but will not be adjusted for any accrued and unpaid interest. In addition, following certain corporate events that occur prior to the maturity date, Alliant Energy will, in certain circumstances, increase the conversion rate for a holder who elects to convert its Notes in connection with such a corporate event.

If Alliant Energy undergoes a fundamental change (as defined in the related Indenture), then, subject to certain conditions, holders of the Notes may require Alliant Energy to repurchase for cash all or any portion of its Notes at a repurchase price equal to 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date.

As of June 30, 2023, the conditions allowing holders of the Notes to convert their Notes were not met, and as a result, the Notes were classified as “Long-term debt, net” on Alliant Energy’s balance sheet. As of June 30, 2023, the net carrying amount of the Notes was $566 million, with unamortized debt issuance costs of $9 million, and the estimated fair value (Level 2) of the Notes was $573 million. As of June 30, 2023, there were no shares of Alliant Energy’s common stock related to the potential conversion of the Notes included in diluted EPS based on Alliant Energy’s average stock prices and the relevant terms of the Notes.

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NOTE 8. 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
Three Months Ended June 30	2023	2022	2023	2022	2023	2022
Electric Utility:
Retail - residential	$284	$289	$151	$158	$133	$131
Retail - commercial	201	196	129	127	72	69
Retail - industrial	245	244	130	136	115	108
Wholesale	49	54	14	16	35	38
Bulk power and other	20	29	7	5	13	24
Total Electric Utility	799	812	431	442	368	370
Gas Utility:
Retail - residential	42	51	24	28	18	23
Retail - commercial	22	27	12	14	10	13
Retail - industrial	3	3	2	2	1	1
Transportation/other	10	13	6	8	4	5
Total Gas Utility	77	94	44	52	33	42
Other Utility:
Steam	11	11	11	11	—	—
Other utility	2	2	1	1	1	1
Total Other Utility	13	13	12	12	1	1
Non-Utility and Other:
Travero and other	23	24	—	—	—	—
Total Non-Utility and Other	23	24	—	—	—	—
Total revenues	$912	$943	$487	$506	$402	$413

	Alliant Energy		IPL		WPL
Six Months Ended June 30	2023	2022	2023	2022	2023	2022
Electric Utility:
Retail - residential	$569	$581	$294	$308	$275	$273
Retail - commercial	385	386	241	246	144	140
Retail - industrial	460	453	236	246	224	207
Wholesale	95	101	26	31	69	70
Bulk power and other	58	65	22	12	36	53
Total Electric Utility	1,567	1,586	819	843	748	743
Gas Utility:
Retail - residential	210	210	117	113	93	97
Retail - commercial	110	109	56	54	54	55
Retail - industrial	9	11	6	7	3	4
Transportation/other	24	26	15	17	9	9
Total Gas Utility	353	356	194	191	159	165
Other Utility:
Steam	22	20	22	20	—	—
Other utility	3	3	2	2	1	1
Total Other Utility	25	23	24	22	1	1
Non-Utility and Other:
Travero and other	45	47	—	—	—	—
Total Non-Utility and Other	45	47	—	—	—	—
Total revenues	$1,990	$2,012	$1,037	$1,056	$908	$909

NOTE 9. INCOME TAXES

Income Tax Rates - Overall effective income tax rates, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences.

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	Alliant Energy				IPL				WPL
	Three Months		Six Months		Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022
Overall income tax rate	—%	2%	(1%)	3%	(17%)	(16%)	(18%)	(15%)	16%	18%	14%	18%

Deferred Tax Assets and Liabilities -

Carryforwards - At June 30, 2023, the carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy	IPL	WPL
State net operating losses	2025-2043	$503	$8	$1
Federal tax credits	2030-2043	708	485	214

NOTE 10. BENEFIT PLANS

NOTE 10(a) Pension and OPEB Plans -

Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are 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.

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
Alliant Energy	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$2	$2	$4	$—	$1	$1	$2
Interest cost	12	9	23	18	2	2	4	3
Expected return on plan assets	(13)	(17)	(26)	(34)	(1)	(2)	(2)	(3)
Amortization of actuarial loss	7	8	14	16	1	—	1	1
	$7	$2	$13	$4	$2	$1	$4	$3

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
IPL	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$1	$2	$3	$—	$1	$—	$1
Interest cost	5	4	10	8	1	—	2	1
Expected return on plan assets	(6)	(8)	(13)	(16)	(1)	(1)	(2)	(2)
Amortization of actuarial loss	3	4	6	7	1	—	1	—
	$3	$1	$5	$2	$1	$—	$1	$—

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
WPL	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$1	$1	$2	$—	$—	$—	$—
Interest cost	5	4	10	8	1	—	2	1
Expected return on plan assets	(6)	(8)	(11)	(16)	—	—	—	—
Amortization of actuarial loss	4	4	7	8	—	1	—	1
	$4	$1	$7	$2	$1	$1	$2	$2

NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and six months ended June 30 was as follows (in millions):

	Alliant Energy				IPL				WPL
	Three Months		Six Months		Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022
Compensation expense	$3	$3	$6	$7	$2	$1	$3	$4	$1	$1	$2	$3
Income tax benefits	1	1	2	2	—	—	1	1	—	—	1	1

As of June 30, 2023, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $15 million, $8 million and $6 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years.

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For the six months ended June 30, 2023, performance shares, performance restricted stock units and restricted stock units were granted to key employees under existing plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards.

		Weighted Average
	Grants	Grant Date Fair Value
Performance shares	106,927	$55.68
Performance restricted stock units	122,178	52.77
Restricted stock units	104,849	52.81

As of June 30, 2023, 206,177 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

NOTE 11. DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Notional Amounts - As of June 30, 2023, 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):

	Electricity		FTRs		Natural Gas		Coal
	MWhs	Years	MWhs	Years	Dths	Years	Tons	Years
Alliant Energy	1,171	2023-2025	24,874	2023-2024	192,421	2023-2032	466	2023
IPL	537	2023-2025	10,163	2023-2024	92,087	2023-2030	224	2023
WPL	634	2023-2025	14,711	2023-2024	100,334	2023-2032	242	2023

Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Current derivative assets	$86	$111	$61	$69	$25	$42
Non-current derivative assets	61	126	34	69	27	57
Current derivative liabilities	54	59	27	40	27	19
Non-current derivative liabilities	43	20	10	6	33	14

During the six months ended June 30, 2023, Alliant Energy’s, IPL’s and WPL’s derivative assets decreased primarily due to settlements of natural gas, FTR and electricity contracts and lower natural gas prices, partially offset by new FTRs resulting from the annual FTR auction in the second quarter of 2023 operated by MISO. Alliant Energy’s and WPL’s derivative liabilities increased primarily due to lower natural gas prices. Based on IPL’s and WPL’s cost recovery mechanisms, the changes in the fair value of derivative liabilities/assets resulted in comparable changes to regulatory assets/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 up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At June 30, 2023 and December 31, 2022, 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, derivative assets and derivative liabilities related to commodity contracts would have been presented on the balance sheets as follows (in millions):

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	Alliant Energy		IPL		WPL
	Gross		Gross		Gross
	(as reported)	Net	(as reported)	Net	(as reported)	Net
June 30, 2023
Derivative assets	$147	$114	$95	$73	$52	$41
Derivative liabilities	97	64	37	15	60	49
December 31, 2022
Derivative assets	237	193	138	108	99	85
Derivative liabilities	79	35	46	16	33	19

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.

Interest Rate Derivative - In January 2023, AEF entered into a $300 million interest rate swap maturing in January 2026 to mitigate interest rate risk. Under the terms of the swap, AEF exchanged a variable interest rate for a fixed interest rate of 3.93% on a portion of its variable-rate term loan borrowings. The related interest rate derivative was valued based on quoted prices that utilize current market interest rate forecasts. As of June 30, 2023, $4 million of non-current interest rate derivative assets was recorded in “Deferred charges and other” on Alliant Energy’s balance sheet. This interest rate derivative was designated as a cash flow hedge, with changes in fair value recorded as other comprehensive income/loss. As of June 30, 2023, accumulated other comprehensive income included $3 million of income related to the interest rate swap. For the three and six months ended June 30, 2023, $1 million and $1 million, respectively, of reductions to interest expense were recorded in Alliant Energy’s income statement related to the interest rate swap.

NOTE 12. FAIR VALUE MEASUREMENTS

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 related estimated fair values of other financial instruments were as follows (in millions):

Alliant Energy	June 30, 2023					December 31, 2022
		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	$6	$6	$—	$—	$6	$10	$10	$—	$—	$10
Commodity derivatives	147	—	80	67	147	237	—	206	31	237
Interest rate derivatives	4	—	4	—	4	—	—	—	—	—
Deferred proceeds	175	—	—	175	175	185	—	—	185	185
Liabilities:
Commodity derivatives	97	—	84	13	97	79	—	67	12	79
Long-term debt (incl. current maturities)	8,595	—	7,950	1	7,951	8,076	—	7,338	1	7,339

IPL	June 30, 2023					December 31, 2022
		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	$6	$6	$—	$—	$6	$10	$10	$—	$—	$10
Commodity derivatives	95	—	44	51	95	138	—	111	27	138
Deferred proceeds	175	—	—	175	175	185	—	—	185	185
Liabilities:
Commodity derivatives	37	—	27	10	37	46	—	35	11	46
Long-term debt	3,702	—	3,321	—	3,321	3,646	—	3,228	—	3,228

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WPL	June 30, 2023					December 31, 2022
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Commodity derivatives	$52	$—	$36	$16	$52	$99	$—	$95	$4	$99
Liabilities:
Commodity derivatives	60	—	57	3	60	33	—	32	1	33
Long-term debt	3,068	—	2,875	—	2,875	2,770	—	2,542	—	2,542

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
Three Months Ended June 30	2023	2022	2023	2022
Beginning balance, April 1	($5)	$10	$153	$227
Total net losses included in changes in net assets (realized/unrealized)	(7)	(10)	—	—
Purchases	62	79	—	—
Sales	(1)	—	—	—
Settlements (a)	5	(7)	22	17
Ending balance, June 30	$54	$72	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($7)	($10)	$—	$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Six Months Ended June 30	2023	2022	2023	2022
Beginning balance, January 1	$19	$29	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(11)	(16)	—	—
Purchases	62	79	—	—
Sales	(1)	—	—	—
Settlements (a)	(15)	(20)	(10)	30
Ending balance, June 30	$54	$72	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($11)	($16)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Three Months Ended June 30	2023	2022	2023	2022
Beginning balance, April 1	$—	$7	$153	$227
Total net losses included in changes in net assets (realized/unrealized)	(13)	(3)	—	—
Purchases	51	58	—	—
Sales	(1)	—	—	—
Settlements (a)	4	(4)	22	17
Ending balance, June 30	$41	$58	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($13)	($3)	$—	$—

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IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Six Months Ended June 30	2023	2022	2023	2022
Beginning balance, January 1	$16	$18	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(12)	(7)	—	—
Purchases	51	58	—	—
Sales	(1)	—	—	—
Settlements (a)	(13)	(11)	(10)	30
Ending balance, June 30	$41	$58	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($12)	($8)	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Three Months Ended June 30	2023	2022
Beginning balance, April 1	($5)	$3
Total net gains (losses) included in changes in net assets (realized/unrealized)	6	(7)
Purchases	11	21
Settlements	1	(3)
Ending balance, June 30	$13	$14
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 June 30	$6	($7)

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Six Months Ended June 30	2023	2022
Beginning balance, January 1	$3	$11
Total net gains (losses) included in changes in net assets (realized/unrealized)	1	(9)
Purchases	11	21
Settlements	(2)	(9)
Ending balance, June 30	$13	$14
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 June 30	$1	($8)

(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 (liabilities) as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
June 30, 2023	($8)	$62	($5)	$46	($3)	$16
December 31, 2022	(10)	29	(9)	25	(1)	4

NOTE 13. COMMITMENTS AND CONTINGENCIES

NOTE 13(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects, including IPL’s and WPL’s expansion of solar generation. At June 30, 2023, Alliant Energy’s, IPL’s and WPL’s minimum future commitments for these projects were $188 million, $87 million and $101 million, respectively.

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NOTE 13(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 June 30, 2023, related minimum future commitments were as follows (in millions):

	Alliant Energy	IPL	WPL
Natural gas	$1,083	$494	$589
Coal	163	79	84
Other (a)	106	51	25
	$1,352	$624	$698

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2023.

NOTE 13(c) 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 June 30, 2023, the currently known partnership obligations for the abandonment obligations are estimated at $58 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 $58 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 June 30, 2023 and December 31, 2022, 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.

Whiting Petroleum completed a business combination with Oasis Petroleum Inc. in July 2022. The combined operations are now known as Chord Energy Corporation. The business combination is not expected to affect the scope of the Whiting Petroleum affiliate’s obligations to Alliant Energy or Alliant Energy’s related 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 $59 million as of June 30, 2023 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 June 30, 2023 and December 31, 2022.

NOTE 13(d) Environmental Matters -

Manufactured Gas Plant (MGP) 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 June 30, 2023, 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):

	Alliant Energy			IPL			WPL
Range of estimated future costs	$9	-	$36	$5	-	$11	$4	-	$25
Current and non-current environmental liabilities	$18			$8			$10

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 Clean Air Act 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.

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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: Cross-State Air Pollution Rule, Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including the Clean Air Act.

NOTE 13(e) MISO Transmission Owner Return on Equity Complaints - A group of stakeholders, including MISO cooperative and municipal utilities, previously filed complaints with the Federal Energy Regulatory Commission (FERC) requesting a reduction to the base return on equity authorized for MISO transmission owners, including ITC Midwest LLC and ATC. In 2019, FERC issued an order on the previously filed complaints and reduced the base return on equity authorized for the MISO transmission owners to 9.88% for November 12, 2013 through February 11, 2015, and subsequent to September 28, 2016. In 2020, FERC issued orders in response to various rehearing requests and increased the base return on equity authorized for the MISO transmission owners from 9.88% to 10.02% for November 12, 2013 through February 11, 2015, and subsequent to September 28, 2016. In August 2022, the U.S. Court of Appeals for the District of Columbia Circuit vacated FERC’s prior orders that established the base return on equity authorized for the MISO transmission owners and remanded the cases to FERC for further proceedings, which may result in additional changes to the base return on equity authorized for the MISO transmission owners. Any further changes in FERC’s decisions may have an impact on Alliant Energy’s share of ATC’s future earnings and customer costs.

NOTE 14. SEGMENTS OF BUSINESS

Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s business segments is as follows. Intersegment revenues were not material to their respective operations.

Alliant Energy					ATC Holdings,	Alliant
	Utility				Non-Utility,	Energy
	Electric	Gas	Other	Total	Parent and Other	Consolidated
	(in millions)
Three Months Ended June 30, 2023
Revenues	$799	$77	$13	$889	$23	$912
Operating income	200	2	7	209	8	217
Net income (loss) attributable to Alliant Energy common shareowners				161	(1)	160
Three Months Ended June 30, 2022
Revenues	$812	$94	$13	$919	$24	$943
Operating income	195	8	1	204	8	212
Net income attributable to Alliant Energy common shareowners				150	9	159

Alliant Energy					ATC Holdings,	Alliant
	Utility				Non-Utility,	Energy
	Electric	Gas	Other	Total	Parent and Other	Consolidated
	(in millions)
Six Months Ended June 30, 2023
Revenues	$1,567	$353	$25	$1,945	$45	$1,990
Operating income	363	52	11	426	13	439
Net income attributable to Alliant Energy common shareowners				321	2	323
Six Months Ended June 30, 2022
Revenues	$1,586	$356	$23	$1,965	$47	$2,012
Operating income	376	65	4	445	15	460
Net income attributable to Alliant Energy common shareowners				329	22	351

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IPL	Electric	Gas	Other	Total
	(in millions)
Three Months Ended June 30, 2023
Revenues	$431	$44	$12	$487
Operating income	105	—	5	110
Net income				89
Three Months Ended June 30, 2022
Revenues	$442	$52	$12	$506
Operating income	104	4	1	109
Net income				87
Six Months Ended June 30, 2023
Revenues	$819	$194	$24	$1,037
Operating income	171	27	8	206
Net income				161
Six Months Ended June 30, 2022
Revenues	$843	$191	$22	$1,056
Operating income	179	36	3	218
Net income				173

WPL	Electric	Gas	Other	Total
	(in millions)
Three Months Ended June 30, 2023
Revenues	$368	$33	$1	$402
Operating income	95	2	2	99
Net income				72
Three Months Ended June 30, 2022
Revenues	$370	$42	$1	$413
Operating income	91	4	—	95
Net income				63
Six Months Ended June 30, 2023
Revenues	$748	$159	$1	$908
Operating income	192	25	3	220
Net income				160
Six Months Ended June 30, 2022
Revenues	$743	$165	$1	$909
Operating income	197	29	1	227
Net income				156

NOTE 15. 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 for the three and six months ended June 30 were as follows (in millions):

	IPL				WPL
	Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022
Corporate Services billings	$48	$51	$88	$91	$43	$42	$80	$78
Sales credited	1	—	8	—	10	13	22	31
Purchases billed	94	129	187	223	2	39	17	61

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Net intercompany payables to Corporate Services were as follows (in millions):

	IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Net payables to Corporate Services	$116	$103	$73	$56

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 for the three and six months ended June 30 were as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
ATC billings to WPL	$44	$35	$78	$69
WPL billings to ATC	5	5	11	8

WPL owed ATC net amounts of $10 million as of June 30, 2023 and $10 million as of December 31, 2022.

ITEM 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

This MDA includes information relating to Alliant Energy, and IPL and WPL (collectively, the Utilities), as well as ATC Holdings, 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 the Notes included in this report, as well as the financial statements, notes and MDA included in the 2022 Form 10-K. Unless otherwise noted, all “per share” references in MDA refer to earnings per diluted share.

2023 HIGHLIGHTS

Key highlights since the filing of the 2022 Form 10-K include the following:

Customer Investments:

•In 2021, IPL filed for advance rate-making principles with the IUB for up to 400 MW of solar generation and 75 MW of battery storage. In April 2023, the IUB approved advance rate-making principles for up to 200 MW of solar generation. The IUB’s order included a cost target of $1,575/kilowatt, including AFUDC and transmission upgrade costs among other costs. Any reasonable and prudent costs incurred in excess of the cost target, as well as the related return on common equity, would need to be addressed in future IPL retail electric rate review filings. In May 2023, IPL requested reconsideration of certain ratemaking principles for the up to 200 MW of solar generation, including the cost target and return on common equity. In June 2023, IPL and the IUB filed a joint motion for remand of the other 200 MW of solar generation and 75 MW of battery storage for further reconsideration by the IUB, which was granted by the court. In June 2023, the IUB granted reconsideration of advance rate-making principles for the 400 MW of solar generation and 75 MW of battery storage. In August 2023, IPL reached a non-unanimous settlement agreement with the Iowa Office of Consumer Advocate, subject to IUB approval, for up to 400 MW of solar generation with a cost target of $735 million, including AFUDC and transmission upgrade costs, and a related return on common equity of 10.75%.

•In June 2023, WPL received an oral decision from the PSCW authorizing WPL to construct, own and operate 175 MW of battery storage, with 100 MW and 75 MW at the Grant County and Wood County solar projects, respectively. A written order from the PSCW is currently expected in the third quarter of 2023.

•In June 2023, WPL filed requests with the PSCW for approval to construct improvements at the natural gas-fired Neenah Energy Facility and Sheboygan Falls Energy Facility, which would increase the capacity and efficiency of the EGUs. Estimated construction costs for these projects are included in the anticipated construction and acquisition expenditures included in “Liquidity and Capital Resources” in the 2022 Form 10-K.

•In March 2023, the IUB issued a certificate of public convenience, use and necessity (GCU Certificate) granting IPL approval to construct, own and operate up to 50 MW of solar generation and up to 25 MW of battery storage at the Creston project in Union County, Iowa.

•In April 2023, the IUB issued a GCU Certificate granting IPL approval to construct, own and operate up to 150 MW of solar generation and up to 75 MW of battery storage at the Wever project in Lee County, Iowa.

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Rate Matters:

•In April 2023, WPL filed a retail electric and gas rate review with the PSCW for the 2024/2025 forward-looking Test Period. The key drivers for the filing include revenue requirement impacts of increasing electric and gas rate base, including investments in solar generation and battery storage. The filing requested approval for WPL to implement increases in annual rates for its retail electric and gas customers of $111 million and $17 million in 2024, respectively, with any granted rate changes expected to be effective on January 1, 2024. WPL’s filing also requested approval to implement an additional $71 million increase in annual rates for its retail electric customers in 2025, with any granted rate changes expected to be effective on January 1, 2025. WPL also requested to maintain its current authorized return on common equity of 10% and implement an approximate 56% common equity component of its regulatory capital structure, as well as receive continued recovery of and a return on the remaining net book value of Edgewater Unit 5, which is currently expected to be retired by June 1, 2025. A decision from the PSCW is expected by the end of 2023.

•IPL currently expects to file a retail electric and gas rate review with the IUB in the third quarter of 2023. The key drivers for the anticipated filing include revenue requirement impacts of increasing electric and gas rate base, including investments in solar generation.

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 for the three months ended June 30 were as follows (dollars in millions, except per share amounts):

	2023		2022
	Income (Loss)	EPS	Income (Loss)	EPS
Utilities and Corporate Services	$164	$0.65	$154	$0.61
ATC Holdings	8	0.03	8	0.03
Non-utility and Parent	(12)	(0.04)	(3)	(0.01)
Alliant Energy Consolidated	$160	$0.64	$159	$0.63

Alliant Energy’s Utilities and Corporate Services net income increased by $10 million for the three-month period, primarily due to higher revenue requirements and AFUDC from WPL’s capital investments, and lower electric fuel-related costs, net of recoveries at WPL. These items were partially offset by lower retail electric and gas sales due to the impact of temperatures on customer demand and higher interest expense.

Alliant Energy’s Non-utility and Parent net income decreased by $9 million for the three-month period, primarily due to higher interest expense.

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For the three and six months ended June 30, 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
Three Months	2023	2022	2023	2022	2023	2022
Operating income	$217	$212	$110	$109	$99	$95
Electric utility revenues	$799	$812	$431	$442	$368	$370
Electric production fuel and purchased power expenses	(166)	(191)	(66)	(83)	(99)	(108)
Electric transmission service expense	(138)	(133)	(96)	(91)	(42)	(41)
Utility Electric Margin (non-GAAP)	495	488	269	268	227	221
Gas utility revenues	77	94	44	52	33	42
Cost of gas sold expense	(33)	(48)	(20)	(27)	(13)	(21)
Utility Gas Margin (non-GAAP)	44	46	24	25	20	21
Other utility revenues	13	13	12	12	1	1
Non-utility revenues	23	24	—	—	—	—
Other operation and maintenance expenses	(163)	(166)	(85)	(87)	(67)	(67)
Depreciation and amortization expenses	(167)	(166)	(96)	(95)	(69)	(69)
Taxes other than income taxes expense	(28)	(27)	(14)	(14)	(13)	(12)
Operating income	$217	$212	$110	$109	$99	$95

	Alliant Energy		IPL		WPL
Six Months	2023	2022	2023	2022	2023	2022
Operating income	$439	$460	$206	$218	$220	$227
Electric utility revenues	$1,567	$1,586	$819	$843	$748	$743
Electric production fuel and purchased power expenses	(322)	(359)	(113)	(150)	(209)	(209)
Electric transmission service expense	(284)	(271)	(201)	(188)	(83)	(83)
Utility Electric Margin (non-GAAP)	961	956	505	505	456	451
Gas utility revenues	353	356	194	191	159	165
Cost of gas sold expense	(215)	(216)	(116)	(112)	(99)	(104)
Utility Gas Margin (non-GAAP)	138	140	78	79	60	61
Other utility revenues	25	23	24	22	1	1
Non-utility revenues	45	47	—	—	—	—
Other operation and maintenance expenses	(338)	(320)	(181)	(171)	(133)	(123)
Depreciation and amortization expenses	(333)	(332)	(191)	(189)	(137)	(139)
Taxes other than income taxes expense	(59)	(54)	(29)	(28)	(27)	(24)
Operating income	$439	$460	$206	$218	$220	$227

Operating Income Variances - Variances between periods in operating income for the three and six months ended June 30, 2023 compared to the same periods in 2022 were as follows (in millions):

	Three Months			Six Months
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Total higher utility electric margin variance (Refer to details below)	$7	$1	$6	$5	$—	$5
Total lower utility gas margin variance (Refer to details below)	(2)	(1)	(1)	(2)	(1)	(1)
Total (higher) lower other operation and maintenance expenses variance (Refer to details below)	3	2	—	(18)	(10)	(10)
Total (higher) lower depreciation and amortization expenses (Refer to Note 2 for discussion of reductions to WPL's depreciation and amortization expense, which was partially offset by WPL's solar generation placed in service in 2022)	(1)	(1)	—	(1)	(2)	2
Other	(2)	—	(1)	(5)	1	(3)
	$5	$1	$4	($21)	($12)	($7)

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Electric and Gas Revenues and Sales Summary - Electric and gas revenues (in millions), and MWh and Dth sales (in thousands), for the three and six months ended June 30 were as follows:

Alliant Energy	Electric				Gas
	Revenues		MWhs Sold		Revenues		Dths Sold
	2023	2022	2023	2022	2023	2022	2023	2022
Three Months
Retail	$730	$729	5,982	6,127	$67	$81	6,303	7,605
Sales for resale:
Wholesale	49	54	678	677	N/A	N/A	N/A	N/A
Bulk power and other	13	15	1,104	779	N/A	N/A	N/A	N/A
Transportation/Other	7	14	14	15	10	13	25,778	22,382
	$799	$812	7,778	7,598	$77	$94	32,081	29,987
Six Months
Retail	$1,414	$1,420	12,182	12,516	$329	$330	28,614	33,701
Sales for resale:
Wholesale	95	101	1,376	1,398	N/A	N/A	N/A	N/A
Bulk power and other	37	36	2,347	2,004	N/A	N/A	N/A	N/A
Transportation/Other	21	29	29	31	24	26	58,392	52,260
	$1,567	$1,586	15,934	15,949	$353	$356	87,006	85,961

IPL	Electric				Gas
	Revenues		MWhs Sold		Revenues		Dths Sold
	2023	2022	2023	2022	2023	2022	2023	2022
Three Months
Retail	$410	$421	3,320	3,434	$38	$44	2,946	3,778
Sales for resale:
Wholesale	14	16	178	179	N/A	N/A	N/A	N/A
Bulk power and other	1	(3)	360	243	N/A	N/A	N/A	N/A
Transportation/Other	6	8	8	8	6	8	9,555	10,154
	$431	$442	3,866	3,864	$44	$52	12,501	13,932
Six Months
Retail	$771	$800	6,863	7,085	$179	$174	14,406	17,380
Sales for resale:
Wholesale	26	31	365	373	N/A	N/A	N/A	N/A
Bulk power and other	9	(5)	856	646	N/A	N/A	N/A	N/A
Transportation/Other	13	17	16	16	15	17	21,589	22,174
	$819	$843	8,100	8,120	$194	$191	35,995	39,554

WPL	Electric				Gas
	Revenues		MWhs Sold		Revenues		Dths Sold
	2023	2022	2023	2022	2023	2022	2023	2022
Three Months
Retail	$320	$308	2,662	2,693	$29	$37	3,357	3,827
Sales for resale:
Wholesale	35	38	500	498	N/A	N/A	N/A	N/A
Bulk power and other	12	18	744	536	N/A	N/A	N/A	N/A
Transportation/Other	1	6	6	7	4	5	16,223	12,228
	$368	$370	3,912	3,734	$33	$42	19,580	16,055
Six Months
Retail	$643	$620	5,319	5,431	$150	$156	14,208	16,321
Sales for resale:
Wholesale	69	70	1,011	1,025	N/A	N/A	N/A	N/A
Bulk power and other	28	41	1,491	1,358	N/A	N/A	N/A	N/A
Transportation/Other	8	12	13	15	9	9	36,803	30,086
	$748	$743	7,834	7,829	$159	$165	51,011	46,407

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Sales Trends and Temperatures - Alliant Energy’s retail electric and gas sales volumes decreased 2% and 17%, respectively, for the three months ended June 30, 2023 compared to the same period in 2022, primarily due to changes in temperatures. Alliant Energy’s retail electric and gas sales volumes decreased 3% and 15%, respectively, for the six months ended June 30, 2023 compared to the same period in 2022, primarily due to changes in temperatures.

Estimated increases (decreases) to electric and gas margins from the impacts of temperatures for the three and six months ended June 30 were as follows (in millions):

	Electric Margins						Gas Margins
	Three Months			Six Months			Three Months			Six Months
	2023	2022	Change	2023	2022	Change	2023	2022	Change	2023	2022	Change
IPL	$—	$7	($7)	($4)	$11	($15)	($1)	$2	($3)	($4)	$4	($8)
WPL	—	8	(8)	(5)	10	(15)	(1)	—	(1)	(3)	2	(5)
Total Alliant Energy	$—	$15	($15)	($9)	$21	($30)	($2)	$2	($4)	($7)	$6	($13)

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 the three and six months ended June 30, 2023 compared to the same periods in 2022 as follows (in millions):

	Three Months			Six Months
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Lower WPL electric fuel-related costs, net of recoveries	$12	$—	$12	$13	$—	$13
Higher revenues at IPL due to changes in the renewable energy rider (mostly offset by changes in income taxes)	5	5	—	12	12	—
Estimated changes in sales volumes caused by temperatures	(15)	(7)	(8)	(30)	(15)	(15)
Other	5	3	2	10	3	7
	$7	$1	$6	$5	$—	$5

Utility Gas Margin Variances - The following items contributed to increased (decreased) utility gas margins for the three and six months ended June 30, 2023 compared to the same periods in 2022 as follows (in millions):

	Three Months			Six Months
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Estimated changes in sales volumes caused by temperatures	($4)	($3)	($1)	($13)	($8)	($5)
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)	1	1	—	7	7	—
Higher revenue requirements at WPL (a)	1	—	1	5	—	5
Other	—	1	(1)	(1)	—	(1)
	($2)	($1)	($1)	($2)	($1)	($1)

(a)In December 2022, the PSCW issued an order authorizing an annual base rate increase of $9 million for WPL’s retail gas customers, covering the 2023 forward-looking Test Period, which reflects changes in weighted average cost of capital, updated depreciation rates and modifications to certain regulatory asset and regulatory liability amortizations. These retail gas rate changes were effective on January 1, 2023 and extend through the end of 2023.

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Other Operation and Maintenance Expenses Variances - The following items contributed to (increased) decreased other operation and maintenance expenses for the three and six months ended June 30, 2023 compared to the same periods in 2022 as follows (in millions):

	Three Months			Six Months
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Higher energy efficiency expense at IPL (mostly offset by higher revenues)	($2)	($2)	$—	($9)	($9)	$—
Higher generation operation and maintenance expenses	(9)	(3)	(6)	(14)	(1)	(13)
Other	14	7	6	5	—	3
	$3	$2	$—	($18)	($10)	($10)

Other Income and Deductions Variances - The following items contributed to (increased) decreased other income and deductions for the three and six months ended June 30, 2023 compared to the same periods in 2022 as follows (in millions):

	Three Months			Six Months
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Higher interest expense primarily due to financings completed in 2023 and 2022, and higher interest rates	($18)	$—	($8)	($38)	$—	($17)
Higher AFUDC primarily due to changes in construction work in progress balances related to WPL’s solar generation	11	1	9	19	3	17
Other	(1)	(1)	4	(2)	(4)	3
	($8)	$—	$5	($21)	($1)	$3

Income Taxes - Refer to Note 9 for details of effective income tax rates.

LIQUIDITY AND CAPITAL RESOURCES

The liquidity and capital resources summary included in the 2022 Form 10-K has not changed materially, except as described below.

Liquidity Position - At June 30, 2023, Alliant Energy had $13 million of cash and cash equivalents, $554 million ($103 million at the parent company, $195 million at IPL and $256 million at WPL) of available capacity under the single revolving credit facility and $50 million of available capacity at IPL under its sales of accounts receivable program.

Capital Structure - Capital structures at June 30, 2023 were as follows (Long-term Debt (including current maturities) (LD); Short-term Debt (SD); Common Equity (CE)):

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

	Alliant Energy		IPL		WPL
	2023	2022	2023	2022	2023	2022
Cash, cash equivalents and restricted cash, January 1	$24	$40	$15	$34	$5	$2
Cash flows from (used for):
Operating activities	311	300	52	83	268	198
Investing activities	(482)	(370)	(15)	60	(402)	(384)
Financing activities	161	50	(43)	(164)	132	188
Net increase (decrease)	(10)	(20)	(6)	(21)	(2)	2
Cash, cash equivalents and restricted cash, June 30	$14	$20	$9	$13	$3	$4

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Operating Activities - The following items contributed to increased (decreased) operating activity cash flows for the six months ended June 30, 2023 compared to the same period in 2022 (in millions):

	Alliant Energy	IPL	WPL
Changes in levels of gas stored underground and prepaid gas costs	$49	$21	$28
Timing of WPL’s fuel-related cost recoveries from retail electric customers	41	—	41
Changes in cash collateral and deposit balances at Corporate Services	14	—	—
Timing of intercompany payments and receipts	—	8	35
Decreased collections from IPL’s and WPL’s retail customers caused by temperature impacts on electric and gas sales	(43)	(23)	(20)
Changes in interest payments	(33)	—	(15)
Higher contributions to qualified defined benefit pension plans	(12)	—	(12)
Other (primarily due to other changes in working capital)	(5)	(37)	13
	$11	($31)	$70

Investing Activities - The following items contributed to increased (decreased) investing activity cash flows for the six months ended June 30, 2023 compared to the same period in 2022 (in millions):

	Alliant Energy	IPL	WPL
Higher utility construction and acquisition expenditures (a)	($208)	($79)	($129)
Higher other construction and acquisition expenditures	(19)	—	—
Proceeds from sales of partial ownership interest in West Riverside	120	—	120
Changes in the amount of cash receipts on sold receivables	39	39	—
Other	(44)	(35)	(9)
	($112)	($75)	($18)

(a)Largely due to higher expenditures for IPL and WPL’s solar generation.

Construction and Acquisition Expenditures - In March 2023, WPL notified the PSCW that it currently expects estimated construction costs and related rate base additions associated with its 414 MW of new solar generation will exceed amounts approved by the PSCW in June 2022 by approximately 10-14% due to higher commodity, labor and other site-specific costs. A significant portion of these higher estimated construction costs are included in the anticipated construction and acquisition expenditures included in “Liquidity and Capital Resources” in the 2022 Form 10-K.

Financing Activities - The following items contributed to increased (decreased) financing activity cash flows for the six months ended June 30, 2023 compared to the same period in 2022 (in millions):

	Alliant Energy	IPL	WPL
Higher net proceeds from issuance of long-term debt	$212	$—	$297
Higher net proceeds from common stock issuances	63	—	—
Higher payments to retire long-term debt	(100)	—	—
Net changes in the amount of commercial paper and other short-term borrowings outstanding	(30)	55	(232)
Capital contributions from noncontrolling interest	(29)	—	(29)
(Higher) lower common stock dividends	(11)	20	(3)
Higher (lower) capital contributions from IPL’s and WPL’s parent company, Alliant Energy	—	40	(85)
Other	6	6	(4)
	$111	$121	($56)

State Regulatory Financing Authorization - In March 2023, WPL received authorization from the PSCW to have up to $500 million of short-term borrowings and/or letters of credit outstanding at any time through the expiration date of WPL’s credit facility agreement.

Common Stock Issuances - Refer to Note 6 for discussion of common stock issuances by Alliant Energy in 2023.

Short-term Debt - Refer to Note 7(a) for discussion of Alliant Energy’s, IPL’s and WPL’s single credit facility agreement that was amended and extended in March 2023, which includes a revised cross-default provision related to prepayment of material debt prior to the stated maturity and certain other confirming changes, as well as details for proceeds from AEF’s December 2022 term loan credit agreement.

Long-term Debt - Refer to Note 7(b) for discussion of various issuances and retirements of long-term debt by Alliant Energy, AEF, IPL and WPL in 2023.

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Interest Rate Risk - As of June 30, 2023, Alliant Energy’s exposure to risk resulting from changes in interest rates associated with variable-rate borrowings was mitigated primarily due to its issuance of convertible senior notes and an interest rate swap on a portion of its variable-rate term loan borrowings, as well as WPL’s issuance of green bonds, all of which were executed in the first quarter of 2023. 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 June 30, 2023, Alliant Energy’s annual pre-tax expense would increase by approximately $7 million.

Off-Balance Sheet Arrangements and Certain Financial Commitments - A summary of Alliant Energy’s and IPL’s off-balance sheet arrangements and Alliant Energy’s, IPL’s and WPL’s contractual obligations is included in the 2022 Form 10-K and has not changed materially from the items reported in the 2022 Form 10-K, except for the items described in Notes 4, 7 and 13.

OTHER MATTERS

Critical Accounting Policies and Estimates - The summary of critical accounting policies and estimates included in the 2022 Form 10-K has not changed materially, except as described below.

Long-Lived Assets -

Regulated Operations -

Generating Units Subject to Early Retirement - In May 2023, IPL retired the Lansing Generating Station. IPL is currently allowed a full recovery of and a full return on this EGU from both its retail and wholesale customers, and as a result, Alliant Energy and IPL concluded that no impairment was required as of June 30, 2023. Refer to Note 2 for further discussion of the Lansing retirement.

Environmental Matters - The summary of environmental matters included in the 2022 Form 10-K has not changed materially, except as described below.

Environmental Regulation -

Clean Air Act (CAA) Section 111(d) - In May 2023, the EPA published proposed standards under Section 111(d) of the CAA, which establish emission guidelines for states to implement Best System of Emission Reduction standards for greenhouse gases emissions from existing fossil-fueled EGUs and certain combustion turbines, and would be phased in beginning in 2030. The EPA also proposed to repeal the Affordable Clean Energy rule. The EPA’s proposed standards would require states to implement plans to reduce carbon dioxide emissions from existing fossil-fueled EGUs and certain combustion turbines through various measures, including retirement, enforceable limits on operational capacity, co-firing with low-greenhouse gases fuels, or other technological controls. State plans must be submitted within 24 months of the final rule’s effective date and are subject to EPA approval. The proposed standards could impact IPL’s coal-fired Ottumwa Generating Station, George Neal Generating Station, Prairie Creek Generating Station Unit 3 and Louisa Generating Station, and IPL’s natural gas-fired Burlington Generating Station and Prairie Creek Generating Station Unit 4. In addition, the proposed standards could impact natural gas-fired combustion turbines with a capacity of 300 MW or more, including IPL’s Marshalltown Generating Station and Emery Generating Station, and WPL’s Riverside Energy Center and West Riverside Energy Center. The proposed standards are currently not expected to impact WPL’s coal-fired Columbia Energy Center or Edgewater Generating Station given current plans to retire these EGUs prior to the proposed 2030 implementation deadline. The timeline for expected issuance of the EPA’s final reconsidered 111(d) rule cannot be predicted with certainty, but is expected to be issued in 2024. 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 May 2023, the EPA published proposed standards under Section 111(b) of the CAA, which establish carbon dioxide emissions limits from certain new and reconstructed fossil-fueled EGUs and would apply prospectively. The timeline for expected issuance of the EPA’s final reconsidered 111(b) rule cannot be predicted with certainty, but is expected to be issued in 2024. Marshalltown and West Riverside are currently subject to the EPA’s Section 111(b) regulation. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these standards.

Coal Combustion Residuals (CCR) Rule - In May 2023, the EPA published proposed amendments to the CCR Rule, which regulates CCR as a non-hazardous waste. These proposed amendments would expand the scope of regulation to include coal ash ponds at sites that no longer produce electricity and inactive landfills, including some IPL and WPL facilities. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these updates.

Environmental Stewardship - Alliant Energy’s current voluntary environmental-related goals include the following:

•By 2030, reduce greenhouse gases emissions from its utility operations by 50% from 2005 levels, reduce its electric utility water supply by 75% from 2005 levels and electrify 100% of its owned light-duty fleet vehicles.

•By 2040, eliminate all coal-fired EGUs from its generating fleet and reduce greenhouse gases emissions from its utility operations by 80% from 2005 levels.

•By 2050, aspire to achieve net-zero greenhouse gases emissions from its utility operations.

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Alliant Energy’s aspirational greenhouse gases goal includes EPA reportable emissions based on applicable regulatory compliance requirements for carbon dioxide, methane and nitrous oxide from its owned fossil-fueled EGUs and distribution of natural gas. In addition, Alliant Energy’s environmental stewardship efforts include a goal to partner to plant more than 1 million trees by the end of 2030. 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.

ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

Quantitative and Qualitative Disclosures About Market Risk are reported in the 2022 Form 10-K and have not changed materially.

ITEM 4. 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 defined in Rule 13a-15(e) of the Securities Exchange Act of 1934, as amended) as of June 30, 2023 pursuant to the requirements of the Securities Exchange Act of 1934, as amended. Based on their evaluation, the Chief Executive Officers and the Chief Financial Officer concluded that Alliant Energy’s, IPL’s and WPL’s disclosure controls and procedures were effective as of the quarter ended June 30, 2023.

There was no change in Alliant Energy’s, IPL’s and WPL’s internal control over financial reporting that occurred during the quarter ended June 30, 2023 that has materially affected, or is reasonably likely to materially affect, Alliant Energy’s, IPL’s or WPL’s internal control over financial reporting.

PART II. OTHER INFORMATION

ITEM 1. 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.

ITEM 1A. RISK FACTORS

The risk factors described in Item 1A in the 2022 Form 10-K have not changed materially.

ITEM 2. UNREGISTERED SALES OF EQUITY SECURITIES AND USE OF PROCEEDS

A summary of Alliant Energy common stock repurchases for the quarter ended June 30, 2023 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)
April 1 through April 30	7,265	$55.05	—	N/A
May 1 through May 31	3,394	53.99	—	N/A
June 1 through June 30	29	52.52	—	N/A
	10,688	54.71	—

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

ITEM 5. OTHER INFORMATION

(c)During the quarter ended June 30, 2023, no director or officer of Alliant Energy, IPL or WPL adopted or terminated a Rule 10b5-1 trading arrangement or non-Rule 10b5-1 trading arrangement, as each term is defined in Item 408(a) of Regulation S-K.

35

Table of Contents

ITEM 6. EXHIBITS

The following Exhibits are filed herewith.

Exhibit Number	Description
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)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, Alliant Energy Corporation, Interstate Power and Light Company and Wisconsin Power and Light Company have each duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized on the 4th day of August 2023.

ALLIANT ENERGY CORPORATION
Registrant
By: /s/ Benjamin M. Bilitz	Chief Accounting Officer and Controller
Benjamin M. Bilitz	(Principal Accounting Officer and Authorized Signatory)

INTERSTATE POWER AND LIGHT COMPANY
Registrant
By: /s/ Benjamin M. Bilitz	Chief Accounting Officer and Controller
Benjamin M. Bilitz	(Principal Accounting Officer and Authorized Signatory)

WISCONSIN POWER AND LIGHT COMPANY
Registrant
By: /s/ Benjamin M. Bilitz	Chief Accounting Officer and Controller
Benjamin M. Bilitz	(Principal Accounting Officer and Authorized Signatory)

36

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 quarterly report on Form 10-Q 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: August 4, 2023

/s/ John O. Larsen

John O. Larsen

Chair 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 quarterly report on Form 10-Q 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: August 4, 2023

/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, Lisa M. Barton, certify that:

1.I have reviewed this quarterly report on Form 10-Q 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: August 4, 2023

/s/ Lisa M. Barton

Lisa M. Barton

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 quarterly report on Form 10-Q 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: August 4, 2023

/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, Lisa M. Barton, certify that:

1.I have reviewed this quarterly report on Form 10-Q 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: August 4, 2023

/s/ Lisa M. Barton

Lisa M. Barton

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 quarterly report on Form 10-Q 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: August 4, 2023

/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 Quarterly Report on Form 10-Q of the Company for the quarter ended June 30, 2023 (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

August 4, 2023

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 Quarterly Report on Form 10-Q of the Company for the quarter ended June 30, 2023 (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/ Lisa M. Barton

Lisa M. Barton

Chief Executive Officer

/s/ Robert J. Durian

Robert J. Durian

Executive Vice President and Chief Financial Officer

August 4, 2023

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 Quarterly Report on Form 10-Q of the Company for the quarter ended June 30, 2023 (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/ Lisa M. Barton

Lisa M. Barton

Chief Executive Officer

/s/ Robert J. Durian

Robert J. Durian

Executive Vice President and Chief Financial Officer

August 4, 2023

XML

Document And Entity Information	6 Months Ended
	Jun. 30, 2023 shares
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2023
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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding	252,719,092
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q2
Amendment Flag	false
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 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 Common Stock, Shares Outstanding	13,370,788
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 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 Common Stock, Shares Outstanding	13,236,601

XML

Condensed Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Revenues:
Electric utility	$ 799	$ 812	$ 1,567	$ 1,586
Gas utility	77	94	353	356
Other utility	13	13	25	23
Non-utility	23	24	45	47
Total revenues	912	943	1,990	2,012
Operating expenses:
Electric production fuel and purchased power	166	191	322	359
Electric transmission service	138	133	284	271
Cost of gas sold	33	48	215	216
Other operation and maintenance	163	166	338	320
Depreciation and amortization	167	166	333	332
Taxes other than income taxes	28	27	59	54
Total operating expenses	695	731	1,551	1,552
Operating income	217	212	439	460
Other (income) and deductions:
Interest expense	96	78	190	152
Equity income from unconsolidated investments, net	(14)	(16)	(31)	(32)
Allowance for funds used during construction	(24)	(13)	(43)	(24)
Other	(1)	0	2	1
Total other (income) and deductions	57	49	118	97
Income before income taxes	160	163	321	363
Income tax expense (benefit)	0	4	(2)	12
Net income			323	351
Net income attributable to common shareowners	$ 160	$ 159	$ 323	$ 351
Weighted average number of common shares outstanding:
Basic (in shares)	251,700	250,900	251,400	250,700
Diluted (in shares)	251,900	251,100	251,600	251,000
Earnings per weighted average common share attributable to Alliant Energy common shareowners:
Basic (in dollars per share)	$ 0.64	$ 0.63	$ 1.28	$ 1.40
Diluted (in dollars per share)	$ 0.64	$ 0.63	$ 1.28	$ 1.40
IPL [Member]
Revenues:
Electric utility	$ 431	$ 442	$ 819	$ 843
Gas utility	44	52	194	191
Other utility	12	12	24	22
Total revenues	487	506	1,037	1,056
Operating expenses:
Electric production fuel and purchased power	66	83	113	150
Electric transmission service	96	91	201	188
Cost of gas sold	20	27	116	112
Other operation and maintenance	85	87	181	171
Depreciation and amortization	96	95	191	189
Taxes other than income taxes	14	14	29	28
Total operating expenses	377	397	831	838
Operating income	110	109	206	218
Other (income) and deductions:
Interest expense	37	37	74	74
Allowance for funds used during construction	(4)	(3)	(8)	(5)
Other	1	0	3	(1)
Total other (income) and deductions	34	34	69	68
Income before income taxes	76	75	137	150
Income tax expense (benefit)	(13)	(12)	(24)	(23)
Net income	89	87	161	173
WPL [Member]
Revenues:
Electric utility	368	370	748	743
Gas utility	33	42	159	165
Other utility	1	1	1	1
Total revenues	402	413	908	909
Operating expenses:
Electric production fuel and purchased power	99	108	209	209
Electric transmission service	42	41	83	83
Cost of gas sold	13	21	99	104
Other operation and maintenance	67	67	133	123
Depreciation and amortization	69	69	137	139
Taxes other than income taxes	13	12	27	24
Total operating expenses	303	318	688	682
Operating income	99	95	220	227
Other (income) and deductions:
Interest expense	36	28	72	55
Allowance for funds used during construction	(19)	(10)	(35)	(18)
Other	(4)	0	(3)	0
Total other (income) and deductions	13	18	34	37
Income before income taxes	86	77	186	190
Income tax expense (benefit)	14	14	26	34
Net income	$ 72	$ 63	$ 160	$ 156

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Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 13	$ 20
Accounts receivable, less allowance for expected credit losses	428	516
Production fuel, at weighted average cost	64	53
Gas stored underground, at weighted average cost	69	132
Materials and supplies, at weighted average cost	172	140
Regulatory assets	196	166
Other	196	223
Total current assets	1,138	1,250
Property, plant and equipment, net	16,306	16,247
Investments:
ATC Holdings	372	358
Other	212	201
Total investments	584	559
Other assets:
Regulatory assets	2,148	1,880
Deferred charges and other	207	227
Total other assets	2,355	2,107
Total assets	20,383	20,163
Current liabilities:
Current maturities of long-term debt	409	408
Commercial paper	391	642
Other short-term borrowings	50	0
Accounts payable	585	756
Regulatory liabilities	121	206
Other	337	351
Total current liabilities	1,893	2,363
Long-term debt, net (excluding current portion)	8,186	7,668
Other liabilities:
Deferred tax liabilities	1,969	1,943
Regulatory liabilities	1,087	1,118
Pension and other benefit obligations	262	277
Other	534	518
Total other liabilities	3,852	3,856
Commitments and contingencies (Note 13)
Common equity:
Common stock	3	3
Additional paid-in capital	2,854	2,777
Retained earnings	3,606	3,509
Accumulated other comprehensive income	3	0
Shares in deferred compensation trust - 405,051 and 402,134 shares at a weighted average cost of $33.69 and $32.63 per share	(14)	(13)
Total common equity	6,452	6,276
Total liabilities and equity	20,383	20,163
IPL [Member]
Current assets:
Cash and cash equivalents	9	15
Accounts receivable, less allowance for expected credit losses	204	259
Production fuel, at weighted average cost	31	23
Gas stored underground, at weighted average cost	27	60
Materials and supplies, at weighted average cost	100	83
Regulatory assets	90	85
Other	78	93
Total current assets	539	618
Property, plant and equipment, net	7,923	8,046
Other assets:
Regulatory assets	1,558	1,301
Deferred charges and other	101	110
Total other assets	1,659	1,411
Total assets	10,121	10,075
Current liabilities:
Accounts payable	247	239
Accounts payable to associated companies	40	28
Accrued taxes	51	52
Accrued interest	35	35
Regulatory liabilities	73	114
Other	97	113
Total current liabilities	543	581
Long-term debt, net (excluding current portion)	3,702	3,646
Other liabilities:
Deferred tax liabilities	1,061	1,047
Regulatory liabilities	603	640
Pension and other benefit obligations	60	62
Other	283	291
Total other liabilities	2,007	2,040
Commitments and contingencies (Note 13)
Common equity:
Common stock	33	33
Additional paid-in capital	2,847	2,807
Retained earnings	989	968
Total common equity	3,869	3,808
Total liabilities and equity	10,121	10,075
WPL [Member]
Current assets:
Cash and cash equivalents	3	5
Accounts receivable, less allowance for expected credit losses	210	244
Production fuel, at weighted average cost	33	29
Gas stored underground, at weighted average cost	42	73
Materials and supplies, at weighted average cost	70	54
Regulatory assets	106	81
Prepaid gross receipts tax	47	42
Other	47	60
Total current assets	558	588
Property, plant and equipment, net	7,882	7,722
Other assets:
Regulatory assets	590	579
Deferred charges and other	69	98
Total other assets	659	677
Total assets	9,099	8,987
Current liabilities:
Commercial paper	44	290
Accounts payable	277	456
Regulatory liabilities	48	92
Other	140	111
Total current liabilities	509	949
Long-term debt, net (excluding current portion)	3,068	2,770
Other liabilities:
Deferred tax liabilities	785	789
Regulatory liabilities	484	478
Pension and other benefit obligations	127	140
Other	387	370
Total other liabilities	1,783	1,777
Commitments and contingencies (Note 13)
Common equity:
Common stock	66	66
Additional paid-in capital	2,413	2,233
Retained earnings	1,260	1,192
Total common equity	3,739	3,491
Total liabilities and equity	$ 9,099	$ 8,987

XML

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2023	Dec. 31, 2022
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)	252,719,092	251,134,966
Shares in deferred compensation trust (in shares)	405,051	402,134
Shares in deferred compensation trust, weighted average cost per share (in dollars per share)	$ 33.69	$ 32.63
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

Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities:
Net income	$ 323	$ 351
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	333	332
Equity component of allowance for funds used during construction	(32)	(18)
Other	14	14
Other changes in assets and liabilities:
Accounts receivable	(186)	(283)
Gas stored underground	63	17
Derivative assets	86	(183)
Regulatory assets	(36)	(116)
Accounts payable	(84)	95
Derivative liabilities	18	86
Regulatory liabilities	(116)	74
Deferred income taxes	24	34
Other	(96)	(103)
Net cash flows from operating activities	311	300
Cash flows from (used for) investing activities:
Utility business construction and acquisition expenditures	(758)	(550)
Other construction and acquisition expenditures	(62)	(43)
Cash receipts on sold receivables	272	233
Proceeds from sales of partial ownership interest in West Riverside	120	0
Other	(54)	(10)
Net cash flows from (used for) investing activities	(482)	(370)
Cash flows from (used for) financing activities:
Common stock dividends	(226)	(215)
Proceeds from issuance of common stock, net	76	13
Proceeds from issuance of long-term debt	862	650
Payments to retire long-term debt	(404)	(304)
Net change in commercial paper and other short-term borrowings	(146)	(116)
Contributions from noncontrolling interest	0	29
Other	(1)	(7)
Net cash flows from (used for) financing activities	161	50
Net increase (decrease) in cash, cash equivalents and restricted cash	(10)	(20)
Cash, cash equivalents and restricted cash at beginning of period	24	40
Cash, cash equivalents and restricted cash at end of period	14	20
Supplemental cash flows information:
Interest	(179)	(146)
Income taxes, net	3	(4)
Significant non-cash investing and financing activities:
Accrued capital expenditures	300	200
Beneficial interest obtained in exchange for securitized accounts receivable	175	244
IPL [Member]
Cash flows from operating activities:
Net income	161	173
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	191	189
Other	2	(9)
Other changes in assets and liabilities:
Accounts receivable	(216)	(256)
Gas stored underground	33	12
Derivative assets	43	(123)
Regulatory assets	(2)	(52)
Accounts payable	(32)	67
Derivative liabilities	(9)	63
Regulatory liabilities	(78)	53
Deferred income taxes	8	24
Other	(49)	(58)
Net cash flows from operating activities	52	83
Cash flows from (used for) investing activities:
Utility business construction and acquisition expenditures	(251)	(172)
Cash receipts on sold receivables	272	233
Other	(36)	(1)
Net cash flows from (used for) investing activities	(15)	60
Cash flows from (used for) financing activities:
Common stock dividends	(140)	(160)
Capital contributions from parent	40	0
Net change in commercial paper and other short-term borrowings	55	0
Other	2	(4)
Net cash flows from (used for) financing activities	(43)	(164)
Net increase (decrease) in cash, cash equivalents and restricted cash	(6)	(21)
Cash, cash equivalents and restricted cash at beginning of period	15	34
Cash, cash equivalents and restricted cash at end of period	9	13
Supplemental cash flows information:
Interest	(74)	(74)
Income taxes, net	25	19
Significant non-cash investing and financing activities:
Accrued capital expenditures	95	45
Beneficial interest obtained in exchange for securitized accounts receivable	175	244
WPL [Member]
Cash flows from operating activities:
Net income	160	156
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	137	139
Equity component of allowance for funds used during construction	(26)	(14)
Other	(4)	18
Other changes in assets and liabilities:
Accounts receivable	33	(17)
Gas stored underground	31	5
Derivative assets	47	(60)
Regulatory assets	(35)	(65)
Accounts payable	(54)	38
Derivative liabilities	27	23
Regulatory liabilities	(38)	20
Other	(10)	(45)
Net cash flows from operating activities	268	198
Cash flows from (used for) investing activities:
Utility business construction and acquisition expenditures	(507)	(378)
Proceeds from sales of partial ownership interest in West Riverside	120	0
Other	(15)	(6)
Net cash flows from (used for) investing activities	(402)	(384)
Cash flows from (used for) financing activities:
Common stock dividends	(92)	(89)
Capital contributions from parent	180	265
Proceeds from issuance of long-term debt	297	0
Net change in commercial paper and other short-term borrowings	(246)	(14)
Contributions from noncontrolling interest	0	29
Other	(7)	(3)
Net cash flows from (used for) financing activities	132	188
Net increase (decrease) in cash, cash equivalents and restricted cash	(2)	2
Cash, cash equivalents and restricted cash at beginning of period	5	2
Cash, cash equivalents and restricted cash at end of period	3	4
Supplemental cash flows information:
Interest	(69)	(54)
Income taxes, net	(42)	(31)
Significant non-cash investing and financing activities:
Accrued capital expenditures	$ 196	$ 150

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Summary Of Significant Accounting Policies

6 Months Ended

Jun. 30, 2023

Summary Of Significant Accounting Policies

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

NOTE 1(a) General - The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the SEC. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the 2022 Form 10-K.

In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the six months ended June 30, 2023 are not necessarily indicative of results that may be expected for the year ending December 31, 2023.

A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred. Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.

IPL [Member]

Summary Of Significant Accounting Policies

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

NOTE 1(a) General - The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the SEC. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the 2022 Form 10-K.

In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the six months ended June 30, 2023 are not necessarily indicative of results that may be expected for the year ending December 31, 2023.

A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred. Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.

WPL [Member]

Summary Of Significant Accounting Policies

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

NOTE 1(a) General - The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the SEC. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the 2022 Form 10-K.

In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the six months ended June 30, 2023 are not necessarily indicative of results that may be expected for the year ending December 31, 2023.

A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred. Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.

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Regulatory Matters

6 Months Ended

Jun. 30, 2023

Public Utilities, General Disclosures [Line Items]

Regulatory Matters

REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

Regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$957	$929	$868	$848	$89	$81
Pension and OPEB costs	378	392	190	197	188	195
Assets retired early	290	70	274	53	16	17
Asset retirement obligations	197	151	156	110	41	41
Commodity cost recovery	145	160	6	1	139	159
Derivatives	102	84	41	48	61	36
IPL’s Duane Arnold Energy Center PPA amendment	54	66	54	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	47	48	—	—	47	48
Other	174	146	59	63	115	83
	$2,344	$2,046	$1,648	$1,386	$696	$660

Assets retired early - In May 2023, IPL retired the coal-fired Lansing Generating Station and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and IPL’s balance sheets. The related regulatory asset balance as of June 30, 2023 was $226 million, which is currently included in IPL’s rate base and IPL is earning a return of and a return on the remaining balance. Continued recovery of the remaining net book value of Lansing is expected to be addressed in future IPL rate reviews.

Derivatives - Refer to Note 11 for discussion of changes in Alliant Energy’s, IPL’s and WPL’s derivative liabilities/assets during the six months ended June 30, 2023, which resulted in comparable changes to regulatory assets/liabilities on the balance sheets.

Regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$572	$579	$301	$303	$271	$276
Cost of removal obligations	405	398	260	259	145	139
Derivatives	90	210	48	115	42	95
Commodity cost recovery	39	40	15	38	24	2
Electric transmission cost recovery	19	20	14	10	5	10
WPL’s West Riverside liquidated damages	17	32	—	—	17	32
Other	66	45	38	29	28	16
	$1,208	$1,324	$676	$754	$532	$570

WPL’s West Riverside liquidated damages - Pursuant to PSCW authorization, WPL’s amortization of liquidated damages related to West Riverside construction procurement contracts was used to offset increases in WPL’s retail electric 2022/2023 Test Period revenue requirement, which resulted in decreases in regulatory liabilities on Alliant Energy’s and WPL’s balance sheets and decreases in depreciation and amortization expenses in Alliant Energy’s and WPL’s income statements for the three and six months ended June 30, 2023.

IPL [Member]

Public Utilities, General Disclosures [Line Items]

Regulatory Matters

REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

Regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$957	$929	$868	$848	$89	$81
Pension and OPEB costs	378	392	190	197	188	195
Assets retired early	290	70	274	53	16	17
Asset retirement obligations	197	151	156	110	41	41
Commodity cost recovery	145	160	6	1	139	159
Derivatives	102	84	41	48	61	36
IPL’s Duane Arnold Energy Center PPA amendment	54	66	54	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	47	48	—	—	47	48
Other	174	146	59	63	115	83
	$2,344	$2,046	$1,648	$1,386	$696	$660

Assets retired early - In May 2023, IPL retired the coal-fired Lansing Generating Station and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and IPL’s balance sheets. The related regulatory asset balance as of June 30, 2023 was $226 million, which is currently included in IPL’s rate base and IPL is earning a return of and a return on the remaining balance. Continued recovery of the remaining net book value of Lansing is expected to be addressed in future IPL rate reviews.

Derivatives - Refer to Note 11 for discussion of changes in Alliant Energy’s, IPL’s and WPL’s derivative liabilities/assets during the six months ended June 30, 2023, which resulted in comparable changes to regulatory assets/liabilities on the balance sheets.

Regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$572	$579	$301	$303	$271	$276
Cost of removal obligations	405	398	260	259	145	139
Derivatives	90	210	48	115	42	95
Commodity cost recovery	39	40	15	38	24	2
Electric transmission cost recovery	19	20	14	10	5	10
WPL’s West Riverside liquidated damages	17	32	—	—	17	32
Other	66	45	38	29	28	16
	$1,208	$1,324	$676	$754	$532	$570

WPL’s West Riverside liquidated damages - Pursuant to PSCW authorization, WPL’s amortization of liquidated damages related to West Riverside construction procurement contracts was used to offset increases in WPL’s retail electric 2022/2023 Test Period revenue requirement, which resulted in decreases in regulatory liabilities on Alliant Energy’s and WPL’s balance sheets and decreases in depreciation and amortization expenses in Alliant Energy’s and WPL’s income statements for the three and six months ended June 30, 2023.

WPL [Member]

Public Utilities, General Disclosures [Line Items]

Regulatory Matters

REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

Regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$957	$929	$868	$848	$89	$81
Pension and OPEB costs	378	392	190	197	188	195
Assets retired early	290	70	274	53	16	17
Asset retirement obligations	197	151	156	110	41	41
Commodity cost recovery	145	160	6	1	139	159
Derivatives	102	84	41	48	61	36
IPL’s Duane Arnold Energy Center PPA amendment	54	66	54	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	47	48	—	—	47	48
Other	174	146	59	63	115	83
	$2,344	$2,046	$1,648	$1,386	$696	$660

Assets retired early - In May 2023, IPL retired the coal-fired Lansing Generating Station and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset on Alliant Energy’s and IPL’s balance sheets. The related regulatory asset balance as of June 30, 2023 was $226 million, which is currently included in IPL’s rate base and IPL is earning a return of and a return on the remaining balance. Continued recovery of the remaining net book value of Lansing is expected to be addressed in future IPL rate reviews.

Derivatives - Refer to Note 11 for discussion of changes in Alliant Energy’s, IPL’s and WPL’s derivative liabilities/assets during the six months ended June 30, 2023, which resulted in comparable changes to regulatory assets/liabilities on the balance sheets.

Regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$572	$579	$301	$303	$271	$276
Cost of removal obligations	405	398	260	259	145	139
Derivatives	90	210	48	115	42	95
Commodity cost recovery	39	40	15	38	24	2
Electric transmission cost recovery	19	20	14	10	5	10
WPL’s West Riverside liquidated damages	17	32	—	—	17	32
Other	66	45	38	29	28	16
	$1,208	$1,324	$676	$754	$532	$570

WPL’s West Riverside liquidated damages - Pursuant to PSCW authorization, WPL’s amortization of liquidated damages related to West Riverside construction procurement contracts was used to offset increases in WPL’s retail electric 2022/2023 Test Period revenue requirement, which resulted in decreases in regulatory liabilities on Alliant Energy’s and WPL’s balance sheets and decreases in depreciation and amortization expenses in Alliant Energy’s and WPL’s income statements for the three and six months ended June 30, 2023.

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Property, Plant and Equipment	6 Months Ended
	Jun. 30, 2023
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENTIn March 2023 and June 2023, Madison Gas and Electric Company and WEC Energy Group, Inc., respectively, acquired partial ownership interests in West Riverside. The related proceeds are included in “Proceeds from sales of partial ownership interest in West Riverside” in investing activities in Alliant Energy’s and WPL’s cash flows statements for the six months ended June 30, 2023. As a result of these transactions, WPL’s undivided current ownership interest in West Riverside is 73.8%.
IPL [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENTIn March 2023 and June 2023, Madison Gas and Electric Company and WEC Energy Group, Inc., respectively, acquired partial ownership interests in West Riverside. The related proceeds are included in “Proceeds from sales of partial ownership interest in West Riverside” in investing activities in Alliant Energy’s and WPL’s cash flows statements for the six months ended June 30, 2023. As a result of these transactions, WPL’s undivided current ownership interest in West Riverside is 73.8%.
WPL [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENTIn March 2023 and June 2023, Madison Gas and Electric Company and WEC Energy Group, Inc., respectively, acquired partial ownership interests in West Riverside. The related proceeds are included in “Proceeds from sales of partial ownership interest in West Riverside” in investing activities in Alliant Energy’s and WPL’s cash flows statements for the six months ended June 30, 2023. As a result of these transactions, WPL’s undivided current ownership interest in West Riverside is 73.8%.

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Receivables

6 Months Ended

Jun. 30, 2023

Receivables [Line Items]

Receivables

RECEIVABLES

NOTE 4(a) - Accounts Receivable - For the three and six months ended June 30, 2023, Alliant Energy’s, IPL’s and WPL’s gross write-offs for accounts receivable were as follows (in millions):

	Originated in 2022		Originated in 2023
	Three Months	Six Months	Three Months	Six Months
Alliant Energy	$3	$8	$2	$2
IPL	2	5	1	1
WPL	1	3	1	1

NOTE 4(b) - Sales of Accounts Receivable - IPL maintains a Receivables Purchase and Sale Agreement (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 March 2023, IPL amended and extended through March 2024 the purchase commitment from the third party to which it sells its receivables. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. As of June 30, 2023, IPL had $50 million of available capacity under its sales of accounts receivable program. IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and six months ended June 30 were as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
Maximum outstanding aggregate cash proceeds	$110	$66	$110	$66
Average outstanding aggregate cash proceeds	101	18	79	11

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

	June 30, 2023	December 31, 2022
Customer accounts receivable	$148	$145
Unbilled utility revenues	100	132
Receivables sold to third party	248	277
Less: cash proceeds	60	80
Deferred proceeds	188	197
Less: allowance for expected credit losses	13	12
Fair value of deferred proceeds	$175	$185

As of June 30, 2023, outstanding receivables past due under the Receivables Agreement were $20 million. Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and six months ended June 30 were as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
Collections	$514	$500	$1,104	$1,061
Write-offs, net of recoveries	2	1	4	3

IPL [Member]

Receivables [Line Items]

Receivables

RECEIVABLES

NOTE 4(a) - Accounts Receivable - For the three and six months ended June 30, 2023, Alliant Energy’s, IPL’s and WPL’s gross write-offs for accounts receivable were as follows (in millions):

	Originated in 2022		Originated in 2023
	Three Months	Six Months	Three Months	Six Months
Alliant Energy	$3	$8	$2	$2
IPL	2	5	1	1
WPL	1	3	1	1

NOTE 4(b) - Sales of Accounts Receivable - IPL maintains a Receivables Purchase and Sale Agreement (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 March 2023, IPL amended and extended through March 2024 the purchase commitment from the third party to which it sells its receivables. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. As of June 30, 2023, IPL had $50 million of available capacity under its sales of accounts receivable program. IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and six months ended June 30 were as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
Maximum outstanding aggregate cash proceeds	$110	$66	$110	$66
Average outstanding aggregate cash proceeds	101	18	79	11

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

	June 30, 2023	December 31, 2022
Customer accounts receivable	$148	$145
Unbilled utility revenues	100	132
Receivables sold to third party	248	277
Less: cash proceeds	60	80
Deferred proceeds	188	197
Less: allowance for expected credit losses	13	12
Fair value of deferred proceeds	$175	$185

As of June 30, 2023, outstanding receivables past due under the Receivables Agreement were $20 million. Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and six months ended June 30 were as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
Collections	$514	$500	$1,104	$1,061
Write-offs, net of recoveries	2	1	4	3

WPL [Member]

Receivables [Line Items]

Receivables

RECEIVABLES

NOTE 4(a) - Accounts Receivable - For the three and six months ended June 30, 2023, Alliant Energy’s, IPL’s and WPL’s gross write-offs for accounts receivable were as follows (in millions):

	Originated in 2022		Originated in 2023
	Three Months	Six Months	Three Months	Six Months
Alliant Energy	$3	$8	$2	$2
IPL	2	5	1	1
WPL	1	3	1	1

XML

Investments

6 Months Ended

Jun. 30, 2023

Schedule of Equity Method Investments [Line Items]

Investments

INVESTMENTS

Unconsolidated Equity Investments - Alliant Energy’s equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three and six months ended June 30 was as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
ATC Holdings	($12)	($11)	($25)	($23)
Other	(2)	(5)	(6)	(9)
	($14)	($16)	($31)	($32)

XML

Common Equity

6 Months Ended

Jun. 30, 2023

Common Equity [Line Items]

Common Equity

COMMON EQUITY

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

Shares outstanding, January 1, 2023	251,134,966
At-the-market offering program	1,221,775
Shareowner Direct Plan	228,017
Equity-based compensation plans	134,334
Shares outstanding, June 30, 2023	252,719,092

At-the-Market Offering Program - In December 2022, Alliant Energy filed a prospectus supplement under which it may sell up to $225 million of its common stock through an at-the-market offering program. As of June 30, 2023, Alliant Energy issued 1,221,775 shares of common stock through this program and received cash proceeds of $64 million, net of $1 million in commissions and fees. Alliant Energy also had commitments not recognized on its balance sheet at June 30, 2023 to sell 172,701 shares of common stock under sales transactions executed through this program in late June 2023. Subsequent to June 30, 2023, Alliant Energy issued shares to settle these transactions in exchange for net cash proceeds of $9 million. The proceeds from the issuances of common stock were used for general corporate purposes.

Changes in Shareowners’ Equity - A summary of changes in shareowners’ equity was as follows (in millions):

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in
		Additional		Other	Deferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Noncontrolling	Total
	Stock	Capital	Earnings	Income (Loss)	Trust	Interest	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$3	$2,780	$3,559	($1)	($13)	$—	$6,328
Net income attributable to Alliant Energy common shareowners			160				160
Common stock dividends ($0.4525 per share)			(113)				(113)
At-the-market offering program and Shareowner Direct Plan issuances		70					70
Equity-based compensation plans and other		4			(1)		3
Other comprehensive income, net of tax				4			4
Ending balance, June 30, 2023	$3	$2,854	$3,606	$3	($14)	$—	$6,452
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$3	$2,750	$3,336	$—	($12)	$—	$6,077
Net income attributable to Alliant Energy common shareowners			159				159
Common stock dividends ($0.4275 per share)			(108)				(108)
Shareowner Direct Plan issuances		6					6
Equity-based compensation plans and other		3					3
Contributions from noncontrolling interest						29	29
Ending balance, June 30, 2022	$3	$2,759	$3,387	$—	($12)	$29	$6,166

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in
		Additional		Other	Deferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Noncontrolling	Total
	Stock	Capital	Earnings	Income (Loss)	Trust	Interest	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$3	$2,777	$3,509	$—	($13)	$—	$6,276
Net income attributable to Alliant Energy common shareowners			323				323
Common stock dividends ($0.905 per share)			(226)				(226)
At-the-market offering program and Shareowner Direct Plan issuances		76					76
Equity-based compensation plans and other		1			(1)		—
Other comprehensive income, net of tax				3			3
Ending balance, June 30, 2023	$3	$2,854	$3,606	$3	($14)	$—	$6,452
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$3	$2,749	$3,250	$—	($12)	$—	$5,990
Net income attributable to Alliant Energy common shareowners			351				351
Common stock dividends ($0.855 per share)			(215)				(215)
Shareowner Direct Plan issuances		13					13
Equity-based compensation plans and other		(3)	1				(2)
Contributions from noncontrolling interest						29	29
Ending balance, June 30, 2022	$3	$2,759	$3,387	$—	($12)	$29	$6,166

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$33	$2,807	$970	$3,810
Net income			89	89
Common stock dividends			(70)	(70)
Capital contributions from parent		40		40
Ending balance, June 30, 2023	$33	$2,847	$989	$3,869
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$33	$2,807	$935	$3,775
Net income			87	87
Common stock dividends			(80)	(80)
Ending balance, June 30, 2022	$33	$2,807	$942	$3,782

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$33	$2,807	$968	$3,808
Net income			161	161
Common stock dividends			(140)	(140)
Capital contributions from parent		40		40
Ending balance, June 30, 2023	$33	$2,847	$989	$3,869
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$33	$2,807	$929	$3,769
Net income			173	173
Common stock dividends			(160)	(160)
Ending balance, June 30, 2022	$33	$2,807	$942	$3,782

WPL	Total WPL Common Equity
		Additional
	Common	Paid-In	Retained	Noncontrolling	Total
	Stock	Capital	Earnings	Interest	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$66	$2,413	$1,234	$—	$3,713
Net income			72		72
Common stock dividends			(46)		(46)
Ending balance, June 30, 2023	$66	$2,413	$1,260	$—	$3,739
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$66	$1,884	$1,101	$—	$3,051
Net income			63		63
Common stock dividends			(44)		(44)
Capital contributions from parent		85			85
Contributions from noncontrolling interest				29	29
Other		(1)			(1)
Ending balance, June 30, 2022	$66	$1,968	$1,120	$29	$3,183

WPL	Total WPL Common Equity
		Additional
	Common	Paid-In	Retained	Noncontrolling	Total
	Stock	Capital	Earnings	Interest	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$66	$2,233	$1,192	$—	$3,491
Net income			160		160
Common stock dividends			(92)		(92)
Capital contributions from parent		180			180
Ending balance, June 30, 2023	$66	$2,413	$1,260	$—	$3,739
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$66	$1,704	$1,053	$—	$2,823
Net income			156		156
Common stock dividends			(89)		(89)
Capital contributions from parent		265			265
Contributions from noncontrolling interest				29	29
Other		(1)			(1)
Ending balance, June 30, 2022	$66	$1,968	$1,120	$29	$3,183

IPL [Member]

Common Equity [Line Items]

Common Equity

COMMON EQUITY

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

Shares outstanding, January 1, 2023	251,134,966
At-the-market offering program	1,221,775
Shareowner Direct Plan	228,017
Equity-based compensation plans	134,334
Shares outstanding, June 30, 2023	252,719,092

At-the-Market Offering Program - In December 2022, Alliant Energy filed a prospectus supplement under which it may sell up to $225 million of its common stock through an at-the-market offering program. As of June 30, 2023, Alliant Energy issued 1,221,775 shares of common stock through this program and received cash proceeds of $64 million, net of $1 million in commissions and fees. Alliant Energy also had commitments not recognized on its balance sheet at June 30, 2023 to sell 172,701 shares of common stock under sales transactions executed through this program in late June 2023. Subsequent to June 30, 2023, Alliant Energy issued shares to settle these transactions in exchange for net cash proceeds of $9 million. The proceeds from the issuances of common stock were used for general corporate purposes.

Changes in Shareowners’ Equity - A summary of changes in shareowners’ equity was as follows (in millions):

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in
		Additional		Other	Deferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Noncontrolling	Total
	Stock	Capital	Earnings	Income (Loss)	Trust	Interest	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$3	$2,780	$3,559	($1)	($13)	$—	$6,328
Net income attributable to Alliant Energy common shareowners			160				160
Common stock dividends ($0.4525 per share)			(113)				(113)
At-the-market offering program and Shareowner Direct Plan issuances		70					70
Equity-based compensation plans and other		4			(1)		3
Other comprehensive income, net of tax				4			4
Ending balance, June 30, 2023	$3	$2,854	$3,606	$3	($14)	$—	$6,452
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$3	$2,750	$3,336	$—	($12)	$—	$6,077
Net income attributable to Alliant Energy common shareowners			159				159
Common stock dividends ($0.4275 per share)			(108)				(108)
Shareowner Direct Plan issuances		6					6
Equity-based compensation plans and other		3					3
Contributions from noncontrolling interest						29	29
Ending balance, June 30, 2022	$3	$2,759	$3,387	$—	($12)	$29	$6,166

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in
		Additional		Other	Deferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Noncontrolling	Total
	Stock	Capital	Earnings	Income (Loss)	Trust	Interest	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$3	$2,777	$3,509	$—	($13)	$—	$6,276
Net income attributable to Alliant Energy common shareowners			323				323
Common stock dividends ($0.905 per share)			(226)				(226)
At-the-market offering program and Shareowner Direct Plan issuances		76					76
Equity-based compensation plans and other		1			(1)		—
Other comprehensive income, net of tax				3			3
Ending balance, June 30, 2023	$3	$2,854	$3,606	$3	($14)	$—	$6,452
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$3	$2,749	$3,250	$—	($12)	$—	$5,990
Net income attributable to Alliant Energy common shareowners			351				351
Common stock dividends ($0.855 per share)			(215)				(215)
Shareowner Direct Plan issuances		13					13
Equity-based compensation plans and other		(3)	1				(2)
Contributions from noncontrolling interest						29	29
Ending balance, June 30, 2022	$3	$2,759	$3,387	$—	($12)	$29	$6,166

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$33	$2,807	$970	$3,810
Net income			89	89
Common stock dividends			(70)	(70)
Capital contributions from parent		40		40
Ending balance, June 30, 2023	$33	$2,847	$989	$3,869
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$33	$2,807	$935	$3,775
Net income			87	87
Common stock dividends			(80)	(80)
Ending balance, June 30, 2022	$33	$2,807	$942	$3,782

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$33	$2,807	$968	$3,808
Net income			161	161
Common stock dividends			(140)	(140)
Capital contributions from parent		40		40
Ending balance, June 30, 2023	$33	$2,847	$989	$3,869
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$33	$2,807	$929	$3,769
Net income			173	173
Common stock dividends			(160)	(160)
Ending balance, June 30, 2022	$33	$2,807	$942	$3,782

WPL	Total WPL Common Equity
		Additional
	Common	Paid-In	Retained	Noncontrolling	Total
	Stock	Capital	Earnings	Interest	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$66	$2,413	$1,234	$—	$3,713
Net income			72		72
Common stock dividends			(46)		(46)
Ending balance, June 30, 2023	$66	$2,413	$1,260	$—	$3,739
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$66	$1,884	$1,101	$—	$3,051
Net income			63		63
Common stock dividends			(44)		(44)
Capital contributions from parent		85			85
Contributions from noncontrolling interest				29	29
Other		(1)			(1)
Ending balance, June 30, 2022	$66	$1,968	$1,120	$29	$3,183

WPL	Total WPL Common Equity
		Additional
	Common	Paid-In	Retained	Noncontrolling	Total
	Stock	Capital	Earnings	Interest	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$66	$2,233	$1,192	$—	$3,491
Net income			160		160
Common stock dividends			(92)		(92)
Capital contributions from parent		180			180
Ending balance, June 30, 2023	$66	$2,413	$1,260	$—	$3,739
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$66	$1,704	$1,053	$—	$2,823
Net income			156		156
Common stock dividends			(89)		(89)
Capital contributions from parent		265			265
Contributions from noncontrolling interest				29	29
Other		(1)			(1)
Ending balance, June 30, 2022	$66	$1,968	$1,120	$29	$3,183

WPL [Member]

Common Equity [Line Items]

Common Equity

COMMON EQUITY

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

Shares outstanding, January 1, 2023	251,134,966
At-the-market offering program	1,221,775
Shareowner Direct Plan	228,017
Equity-based compensation plans	134,334
Shares outstanding, June 30, 2023	252,719,092

At-the-Market Offering Program - In December 2022, Alliant Energy filed a prospectus supplement under which it may sell up to $225 million of its common stock through an at-the-market offering program. As of June 30, 2023, Alliant Energy issued 1,221,775 shares of common stock through this program and received cash proceeds of $64 million, net of $1 million in commissions and fees. Alliant Energy also had commitments not recognized on its balance sheet at June 30, 2023 to sell 172,701 shares of common stock under sales transactions executed through this program in late June 2023. Subsequent to June 30, 2023, Alliant Energy issued shares to settle these transactions in exchange for net cash proceeds of $9 million. The proceeds from the issuances of common stock were used for general corporate purposes.

Changes in Shareowners’ Equity - A summary of changes in shareowners’ equity was as follows (in millions):

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in
		Additional		Other	Deferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Noncontrolling	Total
	Stock	Capital	Earnings	Income (Loss)	Trust	Interest	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$3	$2,780	$3,559	($1)	($13)	$—	$6,328
Net income attributable to Alliant Energy common shareowners			160				160
Common stock dividends ($0.4525 per share)			(113)				(113)
At-the-market offering program and Shareowner Direct Plan issuances		70					70
Equity-based compensation plans and other		4			(1)		3
Other comprehensive income, net of tax				4			4
Ending balance, June 30, 2023	$3	$2,854	$3,606	$3	($14)	$—	$6,452
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$3	$2,750	$3,336	$—	($12)	$—	$6,077
Net income attributable to Alliant Energy common shareowners			159				159
Common stock dividends ($0.4275 per share)			(108)				(108)
Shareowner Direct Plan issuances		6					6
Equity-based compensation plans and other		3					3
Contributions from noncontrolling interest						29	29
Ending balance, June 30, 2022	$3	$2,759	$3,387	$—	($12)	$29	$6,166

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in
		Additional		Other	Deferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Noncontrolling	Total
	Stock	Capital	Earnings	Income (Loss)	Trust	Interest	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$3	$2,777	$3,509	$—	($13)	$—	$6,276
Net income attributable to Alliant Energy common shareowners			323				323
Common stock dividends ($0.905 per share)			(226)				(226)
At-the-market offering program and Shareowner Direct Plan issuances		76					76
Equity-based compensation plans and other		1			(1)		—
Other comprehensive income, net of tax				3			3
Ending balance, June 30, 2023	$3	$2,854	$3,606	$3	($14)	$—	$6,452
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$3	$2,749	$3,250	$—	($12)	$—	$5,990
Net income attributable to Alliant Energy common shareowners			351				351
Common stock dividends ($0.855 per share)			(215)				(215)
Shareowner Direct Plan issuances		13					13
Equity-based compensation plans and other		(3)	1				(2)
Contributions from noncontrolling interest						29	29
Ending balance, June 30, 2022	$3	$2,759	$3,387	$—	($12)	$29	$6,166

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$33	$2,807	$970	$3,810
Net income			89	89
Common stock dividends			(70)	(70)
Capital contributions from parent		40		40
Ending balance, June 30, 2023	$33	$2,847	$989	$3,869
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$33	$2,807	$935	$3,775
Net income			87	87
Common stock dividends			(80)	(80)
Ending balance, June 30, 2022	$33	$2,807	$942	$3,782

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$33	$2,807	$968	$3,808
Net income			161	161
Common stock dividends			(140)	(140)
Capital contributions from parent		40		40
Ending balance, June 30, 2023	$33	$2,847	$989	$3,869
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$33	$2,807	$929	$3,769
Net income			173	173
Common stock dividends			(160)	(160)
Ending balance, June 30, 2022	$33	$2,807	$942	$3,782

WPL	Total WPL Common Equity
		Additional
	Common	Paid-In	Retained	Noncontrolling	Total
	Stock	Capital	Earnings	Interest	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$66	$2,413	$1,234	$—	$3,713
Net income			72		72
Common stock dividends			(46)		(46)
Ending balance, June 30, 2023	$66	$2,413	$1,260	$—	$3,739
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$66	$1,884	$1,101	$—	$3,051
Net income			63		63
Common stock dividends			(44)		(44)
Capital contributions from parent		85			85
Contributions from noncontrolling interest				29	29
Other		(1)			(1)
Ending balance, June 30, 2022	$66	$1,968	$1,120	$29	$3,183

WPL	Total WPL Common Equity
		Additional
	Common	Paid-In	Retained	Noncontrolling	Total
	Stock	Capital	Earnings	Interest	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$66	$2,233	$1,192	$—	$3,491
Net income			160		160
Common stock dividends			(92)		(92)
Capital contributions from parent		180			180
Ending balance, June 30, 2023	$66	$2,413	$1,260	$—	$3,739
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$66	$1,704	$1,053	$—	$2,823
Net income			156		156
Common stock dividends			(89)		(89)
Capital contributions from parent		265			265
Contributions from noncontrolling interest				29	29
Other		(1)			(1)
Ending balance, June 30, 2022	$66	$1,968	$1,120	$29	$3,183

XML

Debt

6 Months Ended

Jun. 30, 2023

Debt [Line Items]

Debt

DEBT

NOTE 7(a) Short-term Debt - In March 2023, Alliant Energy, IPL and WPL extended their single credit facility agreement, which currently expires in December 2027, and reallocated credit facility capacity amounts to $450 million for Alliant Energy at the parent company level, $250 million for IPL and $300 million for WPL, within the $1 billion total commitment. Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions):

June 30, 2023	Alliant Energy	IPL	WPL
Amount outstanding	$391	$—	$44
Weighted average interest rates	5.3%	—%	5.2%
Available credit facility capacity (a)	$554	$195	$256

	Alliant Energy		IPL		WPL
Three Months Ended June 30	2023	2022	2023	2022	2023	2022
Maximum amount outstanding (based on daily outstanding balances)	$391	$441	$70	$—	$91	$222
Average amount outstanding (based on daily outstanding balances)	$88	$337	$6	$—	$18	$166
Weighted average interest rates	5.3%	1.0%	5.3%	—%	5.2%	0.9%
Six Months Ended June 30
Maximum amount outstanding (based on daily outstanding balances)	$793	$577	$70	$—	$349	$252
Average amount outstanding (based on daily outstanding balances)	$330	$390	$3	$—	$160	$185
Weighted average interest rates	4.8%	0.6%	5.3%	—%	4.8%	0.5%

(a)Alliant Energy’s and IPL’s available credit facility capacities reflect outstanding commercial paper classified as both short- and long-term debt at June 30, 2023.

In January 2023, AEF received $50 million of proceeds from its December 2022 term loan credit agreement, which was classified as “Other short-term borrowings” on Alliant Energy’s balance sheet as of June 30, 2023.

NOTE 7(b) Long-term Debt - In June 2023, AEF retired its $400 million 3.75% senior notes. In March 2023, WPL issued $300 million of 4.95% debentures due 2033. WPL’s debentures were issued as green bonds, and an amount equal to or in excess of the net proceeds will be allocated or disbursed for the development and acquisition of its solar EGUs.

As of June 30, 2023, $55 million of commercial paper was recorded in “Long-term debt, net” on Alliant Energy’s and IPL’s balance sheets due to the existence of the long-term single credit facility that back-stops this commercial paper balance, along with Alliant Energy’s and IPL’s intent and ability to refinance these balances on a long-term basis. As of June 30, 2023, this commercial paper balance had a 5% interest rate.

Convertible Senior Notes - In March 2023, Alliant Energy issued $575 million of 3.875% convertible senior notes (the Notes), which are senior unsecured obligations, and used the net proceeds from the issuance for general corporate purposes. The Notes will mature on March 15, 2026 unless earlier converted or repurchased, and no sinking fund is provided for the Notes. Alliant Energy may not redeem the Notes prior to the maturity date. Holders may convert their Notes at their option at any time prior to the close of business on the business day immediately preceding December 15, 2025 only under the following circumstances:

•during any calendar quarter commencing after the calendar quarter ending on June 30, 2023 (and only during such calendar quarter), if the last reported sale price of Alliant Energy’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day during such period;

•during the 5 business day period after any 10 consecutive trading day period (the “measurement period”) in which the trading price (as defined in the related Indenture) per $1,000 principal amount of Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of Alliant Energy’s common stock and the conversion rate on each such trading day; or

•upon the occurrence of specified corporate events.

On or after December 15, 2025 until the close of business on the business day immediately preceding the maturity date, holders may convert all or any portion of their Notes at any time, regardless of the foregoing circumstances. Upon conversion of the Notes, Alliant Energy will pay cash up to the aggregate principal amount of the Notes to be converted and pay or deliver, as the case may be, cash, shares of its common stock or a combination of cash and shares of its common stock, at its election, in respect of the remainder, if any, of its conversion obligation in excess of the aggregate principal amount of the Notes being converted.

The initial conversion rate is 15.5461 shares of common stock per $1,000 principal amount of Notes (equivalent to an initial conversion price of approximately $64.32 per share of Alliant Energy’s common stock). The conversion rate is subject to adjustment in some events but will not be adjusted for any accrued and unpaid interest. In addition, following certain corporate events that occur prior to the maturity date, Alliant Energy will, in certain circumstances, increase the conversion rate for a holder who elects to convert its Notes in connection with such a corporate event.

If Alliant Energy undergoes a fundamental change (as defined in the related Indenture), then, subject to certain conditions, holders of the Notes may require Alliant Energy to repurchase for cash all or any portion of its Notes at a repurchase price equal to 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date.

As of June 30, 2023, the conditions allowing holders of the Notes to convert their Notes were not met, and as a result, the Notes were classified as “Long-term debt, net” on Alliant Energy’s balance sheet. As of June 30, 2023, the net carrying amount of the Notes was $566 million, with unamortized debt issuance costs of $9 million, and the estimated fair value (Level 2) of the Notes was $573 million. As of June 30, 2023, there were no shares of Alliant Energy’s common stock related to the potential conversion of the Notes included in diluted EPS based on Alliant Energy’s average stock prices and the relevant terms of the Notes.

IPL [Member]

Debt [Line Items]

Debt

DEBT

NOTE 7(a) Short-term Debt - In March 2023, Alliant Energy, IPL and WPL extended their single credit facility agreement, which currently expires in December 2027, and reallocated credit facility capacity amounts to $450 million for Alliant Energy at the parent company level, $250 million for IPL and $300 million for WPL, within the $1 billion total commitment. Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions):

June 30, 2023	Alliant Energy	IPL	WPL
Amount outstanding	$391	$—	$44
Weighted average interest rates	5.3%	—%	5.2%
Available credit facility capacity (a)	$554	$195	$256

	Alliant Energy		IPL		WPL
Three Months Ended June 30	2023	2022	2023	2022	2023	2022
Maximum amount outstanding (based on daily outstanding balances)	$391	$441	$70	$—	$91	$222
Average amount outstanding (based on daily outstanding balances)	$88	$337	$6	$—	$18	$166
Weighted average interest rates	5.3%	1.0%	5.3%	—%	5.2%	0.9%
Six Months Ended June 30
Maximum amount outstanding (based on daily outstanding balances)	$793	$577	$70	$—	$349	$252
Average amount outstanding (based on daily outstanding balances)	$330	$390	$3	$—	$160	$185
Weighted average interest rates	4.8%	0.6%	5.3%	—%	4.8%	0.5%

(a)Alliant Energy’s and IPL’s available credit facility capacities reflect outstanding commercial paper classified as both short- and long-term debt at June 30, 2023.

In January 2023, AEF received $50 million of proceeds from its December 2022 term loan credit agreement, which was classified as “Other short-term borrowings” on Alliant Energy’s balance sheet as of June 30, 2023.

NOTE 7(b) Long-term Debt - In June 2023, AEF retired its $400 million 3.75% senior notes. In March 2023, WPL issued $300 million of 4.95% debentures due 2033. WPL’s debentures were issued as green bonds, and an amount equal to or in excess of the net proceeds will be allocated or disbursed for the development and acquisition of its solar EGUs.

As of June 30, 2023, $55 million of commercial paper was recorded in “Long-term debt, net” on Alliant Energy’s and IPL’s balance sheets due to the existence of the long-term single credit facility that back-stops this commercial paper balance, along with Alliant Energy’s and IPL’s intent and ability to refinance these balances on a long-term basis. As of June 30, 2023, this commercial paper balance had a 5% interest rate.

WPL [Member]

Debt [Line Items]

Debt

DEBT

NOTE 7(a) Short-term Debt - In March 2023, Alliant Energy, IPL and WPL extended their single credit facility agreement, which currently expires in December 2027, and reallocated credit facility capacity amounts to $450 million for Alliant Energy at the parent company level, $250 million for IPL and $300 million for WPL, within the $1 billion total commitment. Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions):

June 30, 2023	Alliant Energy	IPL	WPL
Amount outstanding	$391	$—	$44
Weighted average interest rates	5.3%	—%	5.2%
Available credit facility capacity (a)	$554	$195	$256

	Alliant Energy		IPL		WPL
Three Months Ended June 30	2023	2022	2023	2022	2023	2022
Maximum amount outstanding (based on daily outstanding balances)	$391	$441	$70	$—	$91	$222
Average amount outstanding (based on daily outstanding balances)	$88	$337	$6	$—	$18	$166
Weighted average interest rates	5.3%	1.0%	5.3%	—%	5.2%	0.9%
Six Months Ended June 30
Maximum amount outstanding (based on daily outstanding balances)	$793	$577	$70	$—	$349	$252
Average amount outstanding (based on daily outstanding balances)	$330	$390	$3	$—	$160	$185
Weighted average interest rates	4.8%	0.6%	5.3%	—%	4.8%	0.5%

(a)Alliant Energy’s and IPL’s available credit facility capacities reflect outstanding commercial paper classified as both short- and long-term debt at June 30, 2023.

In January 2023, AEF received $50 million of proceeds from its December 2022 term loan credit agreement, which was classified as “Other short-term borrowings” on Alliant Energy’s balance sheet as of June 30, 2023.

NOTE 7(b) Long-term Debt - In June 2023, AEF retired its $400 million 3.75% senior notes. In March 2023, WPL issued $300 million of 4.95% debentures due 2033. WPL’s debentures were issued as green bonds, and an amount equal to or in excess of the net proceeds will be allocated or disbursed for the development and acquisition of its solar EGUs.

XML

Revenues

6 Months Ended

Jun. 30, 2023

Disaggregation of Revenue [Line Items]

Revenues from Contracts with Customers

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
Three Months Ended June 30	2023	2022	2023	2022	2023	2022
Electric Utility:
Retail - residential	$284	$289	$151	$158	$133	$131
Retail - commercial	201	196	129	127	72	69
Retail - industrial	245	244	130	136	115	108
Wholesale	49	54	14	16	35	38
Bulk power and other	20	29	7	5	13	24
Total Electric Utility	799	812	431	442	368	370
Gas Utility:
Retail - residential	42	51	24	28	18	23
Retail - commercial	22	27	12	14	10	13
Retail - industrial	3	3	2	2	1	1
Transportation/other	10	13	6	8	4	5
Total Gas Utility	77	94	44	52	33	42
Other Utility:
Steam	11	11	11	11	—	—
Other utility	2	2	1	1	1	1
Total Other Utility	13	13	12	12	1	1
Non-Utility and Other:
Travero and other	23	24	—	—	—	—
Total Non-Utility and Other	23	24	—	—	—	—
Total revenues	$912	$943	$487	$506	$402	$413

	Alliant Energy		IPL		WPL
Six Months Ended June 30	2023	2022	2023	2022	2023	2022
Electric Utility:
Retail - residential	$569	$581	$294	$308	$275	$273
Retail - commercial	385	386	241	246	144	140
Retail - industrial	460	453	236	246	224	207
Wholesale	95	101	26	31	69	70
Bulk power and other	58	65	22	12	36	53
Total Electric Utility	1,567	1,586	819	843	748	743
Gas Utility:
Retail - residential	210	210	117	113	93	97
Retail - commercial	110	109	56	54	54	55
Retail - industrial	9	11	6	7	3	4
Transportation/other	24	26	15	17	9	9
Total Gas Utility	353	356	194	191	159	165
Other Utility:
Steam	22	20	22	20	—	—
Other utility	3	3	2	2	1	1
Total Other Utility	25	23	24	22	1	1
Non-Utility and Other:
Travero and other	45	47	—	—	—	—
Total Non-Utility and Other	45	47	—	—	—	—
Total revenues	$1,990	$2,012	$1,037	$1,056	$908	$909

IPL [Member]

Disaggregation of Revenue [Line Items]

Revenues from Contracts with Customers

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
Three Months Ended June 30	2023	2022	2023	2022	2023	2022
Electric Utility:
Retail - residential	$284	$289	$151	$158	$133	$131
Retail - commercial	201	196	129	127	72	69
Retail - industrial	245	244	130	136	115	108
Wholesale	49	54	14	16	35	38
Bulk power and other	20	29	7	5	13	24
Total Electric Utility	799	812	431	442	368	370
Gas Utility:
Retail - residential	42	51	24	28	18	23
Retail - commercial	22	27	12	14	10	13
Retail - industrial	3	3	2	2	1	1
Transportation/other	10	13	6	8	4	5
Total Gas Utility	77	94	44	52	33	42
Other Utility:
Steam	11	11	11	11	—	—
Other utility	2	2	1	1	1	1
Total Other Utility	13	13	12	12	1	1
Non-Utility and Other:
Travero and other	23	24	—	—	—	—
Total Non-Utility and Other	23	24	—	—	—	—
Total revenues	$912	$943	$487	$506	$402	$413

	Alliant Energy		IPL		WPL
Six Months Ended June 30	2023	2022	2023	2022	2023	2022
Electric Utility:
Retail - residential	$569	$581	$294	$308	$275	$273
Retail - commercial	385	386	241	246	144	140
Retail - industrial	460	453	236	246	224	207
Wholesale	95	101	26	31	69	70
Bulk power and other	58	65	22	12	36	53
Total Electric Utility	1,567	1,586	819	843	748	743
Gas Utility:
Retail - residential	210	210	117	113	93	97
Retail - commercial	110	109	56	54	54	55
Retail - industrial	9	11	6	7	3	4
Transportation/other	24	26	15	17	9	9
Total Gas Utility	353	356	194	191	159	165
Other Utility:
Steam	22	20	22	20	—	—
Other utility	3	3	2	2	1	1
Total Other Utility	25	23	24	22	1	1
Non-Utility and Other:
Travero and other	45	47	—	—	—	—
Total Non-Utility and Other	45	47	—	—	—	—
Total revenues	$1,990	$2,012	$1,037	$1,056	$908	$909

WPL [Member]

Disaggregation of Revenue [Line Items]

Revenues from Contracts with Customers

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
Three Months Ended June 30	2023	2022	2023	2022	2023	2022
Electric Utility:
Retail - residential	$284	$289	$151	$158	$133	$131
Retail - commercial	201	196	129	127	72	69
Retail - industrial	245	244	130	136	115	108
Wholesale	49	54	14	16	35	38
Bulk power and other	20	29	7	5	13	24
Total Electric Utility	799	812	431	442	368	370
Gas Utility:
Retail - residential	42	51	24	28	18	23
Retail - commercial	22	27	12	14	10	13
Retail - industrial	3	3	2	2	1	1
Transportation/other	10	13	6	8	4	5
Total Gas Utility	77	94	44	52	33	42
Other Utility:
Steam	11	11	11	11	—	—
Other utility	2	2	1	1	1	1
Total Other Utility	13	13	12	12	1	1
Non-Utility and Other:
Travero and other	23	24	—	—	—	—
Total Non-Utility and Other	23	24	—	—	—	—
Total revenues	$912	$943	$487	$506	$402	$413

	Alliant Energy		IPL		WPL
Six Months Ended June 30	2023	2022	2023	2022	2023	2022
Electric Utility:
Retail - residential	$569	$581	$294	$308	$275	$273
Retail - commercial	385	386	241	246	144	140
Retail - industrial	460	453	236	246	224	207
Wholesale	95	101	26	31	69	70
Bulk power and other	58	65	22	12	36	53
Total Electric Utility	1,567	1,586	819	843	748	743
Gas Utility:
Retail - residential	210	210	117	113	93	97
Retail - commercial	110	109	56	54	54	55
Retail - industrial	9	11	6	7	3	4
Transportation/other	24	26	15	17	9	9
Total Gas Utility	353	356	194	191	159	165
Other Utility:
Steam	22	20	22	20	—	—
Other utility	3	3	2	2	1	1
Total Other Utility	25	23	24	22	1	1
Non-Utility and Other:
Travero and other	45	47	—	—	—	—
Total Non-Utility and Other	45	47	—	—	—	—
Total revenues	$1,990	$2,012	$1,037	$1,056	$908	$909

XML

Income Taxes

6 Months Ended

Jun. 30, 2023

Income Taxes [Line Items]

Income Taxes

INCOME TAXESIncome Tax Rates - Overall effective income tax rates, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences.

	Alliant Energy				IPL				WPL
	Three Months		Six Months		Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022
Overall income tax rate	—%	2%	(1%)	3%	(17%)	(16%)	(18%)	(15%)	16%	18%	14%	18%

Deferred Tax Assets and Liabilities -

Carryforwards - At June 30, 2023, the carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy	IPL	WPL
State net operating losses	2025-2043	$503	$8	$1
Federal tax credits	2030-2043	708	485	214

IPL [Member]

Income Taxes [Line Items]

Income Taxes

INCOME TAXESIncome Tax Rates - Overall effective income tax rates, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences.

	Alliant Energy				IPL				WPL
	Three Months		Six Months		Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022
Overall income tax rate	—%	2%	(1%)	3%	(17%)	(16%)	(18%)	(15%)	16%	18%	14%	18%

Deferred Tax Assets and Liabilities -

Carryforwards - At June 30, 2023, the carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy	IPL	WPL
State net operating losses	2025-2043	$503	$8	$1
Federal tax credits	2030-2043	708	485	214

WPL [Member]

Income Taxes [Line Items]

Income Taxes

INCOME TAXESIncome Tax Rates - Overall effective income tax rates, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences.

	Alliant Energy				IPL				WPL
	Three Months		Six Months		Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022
Overall income tax rate	—%	2%	(1%)	3%	(17%)	(16%)	(18%)	(15%)	16%	18%	14%	18%

Deferred Tax Assets and Liabilities -

Carryforwards - At June 30, 2023, the carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy	IPL	WPL
State net operating losses	2025-2043	$503	$8	$1
Federal tax credits	2030-2043	708	485	214

XML

Benefit Plans

6 Months Ended

Jun. 30, 2023

Benefit Plans

BENEFIT PLANS

NOTE 10(a) Pension and OPEB Plans -

Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are 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.

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
Alliant Energy	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$2	$2	$4	$—	$1	$1	$2
Interest cost	12	9	23	18	2	2	4	3
Expected return on plan assets	(13)	(17)	(26)	(34)	(1)	(2)	(2)	(3)
Amortization of actuarial loss	7	8	14	16	1	—	1	1
	$7	$2	$13	$4	$2	$1	$4	$3

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
IPL	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$1	$2	$3	$—	$1	$—	$1
Interest cost	5	4	10	8	1	—	2	1
Expected return on plan assets	(6)	(8)	(13)	(16)	(1)	(1)	(2)	(2)
Amortization of actuarial loss	3	4	6	7	1	—	1	—
	$3	$1	$5	$2	$1	$—	$1	$—

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
WPL	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$1	$1	$2	$—	$—	$—	$—
Interest cost	5	4	10	8	1	—	2	1
Expected return on plan assets	(6)	(8)	(11)	(16)	—	—	—	—
Amortization of actuarial loss	4	4	7	8	—	1	—	1
	$4	$1	$7	$2	$1	$1	$2	$2

NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and six months ended June 30 was as follows (in millions):

	Alliant Energy				IPL				WPL
	Three Months		Six Months		Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022
Compensation expense	$3	$3	$6	$7	$2	$1	$3	$4	$1	$1	$2	$3
Income tax benefits	1	1	2	2	—	—	1	1	—	—	1	1

As of June 30, 2023, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $15 million, $8 million and $6 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years.

For the six months ended June 30, 2023, performance shares, performance restricted stock units and restricted stock units were granted to key employees under existing plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards.

		Weighted Average
	Grants	Grant Date Fair Value
Performance shares	106,927	$55.68
Performance restricted stock units	122,178	52.77
Restricted stock units	104,849	52.81

As of June 30, 2023, 206,177 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

IPL [Member]

Benefit Plans

BENEFIT PLANS

NOTE 10(a) Pension and OPEB Plans -

Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are 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.

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
Alliant Energy	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$2	$2	$4	$—	$1	$1	$2
Interest cost	12	9	23	18	2	2	4	3
Expected return on plan assets	(13)	(17)	(26)	(34)	(1)	(2)	(2)	(3)
Amortization of actuarial loss	7	8	14	16	1	—	1	1
	$7	$2	$13	$4	$2	$1	$4	$3

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
IPL	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$1	$2	$3	$—	$1	$—	$1
Interest cost	5	4	10	8	1	—	2	1
Expected return on plan assets	(6)	(8)	(13)	(16)	(1)	(1)	(2)	(2)
Amortization of actuarial loss	3	4	6	7	1	—	1	—
	$3	$1	$5	$2	$1	$—	$1	$—

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
WPL	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$1	$1	$2	$—	$—	$—	$—
Interest cost	5	4	10	8	1	—	2	1
Expected return on plan assets	(6)	(8)	(11)	(16)	—	—	—	—
Amortization of actuarial loss	4	4	7	8	—	1	—	1
	$4	$1	$7	$2	$1	$1	$2	$2

NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and six months ended June 30 was as follows (in millions):

	Alliant Energy				IPL				WPL
	Three Months		Six Months		Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022
Compensation expense	$3	$3	$6	$7	$2	$1	$3	$4	$1	$1	$2	$3
Income tax benefits	1	1	2	2	—	—	1	1	—	—	1	1

As of June 30, 2023, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $15 million, $8 million and $6 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years.

For the six months ended June 30, 2023, performance shares, performance restricted stock units and restricted stock units were granted to key employees under existing plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards.

		Weighted Average
	Grants	Grant Date Fair Value
Performance shares	106,927	$55.68
Performance restricted stock units	122,178	52.77
Restricted stock units	104,849	52.81

As of June 30, 2023, 206,177 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

WPL [Member]

Benefit Plans

BENEFIT PLANS

NOTE 10(a) Pension and OPEB Plans -

Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are 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.

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
Alliant Energy	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$2	$2	$4	$—	$1	$1	$2
Interest cost	12	9	23	18	2	2	4	3
Expected return on plan assets	(13)	(17)	(26)	(34)	(1)	(2)	(2)	(3)
Amortization of actuarial loss	7	8	14	16	1	—	1	1
	$7	$2	$13	$4	$2	$1	$4	$3

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
IPL	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$1	$2	$3	$—	$1	$—	$1
Interest cost	5	4	10	8	1	—	2	1
Expected return on plan assets	(6)	(8)	(13)	(16)	(1)	(1)	(2)	(2)
Amortization of actuarial loss	3	4	6	7	1	—	1	—
	$3	$1	$5	$2	$1	$—	$1	$—

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
WPL	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$1	$1	$2	$—	$—	$—	$—
Interest cost	5	4	10	8	1	—	2	1
Expected return on plan assets	(6)	(8)	(11)	(16)	—	—	—	—
Amortization of actuarial loss	4	4	7	8	—	1	—	1
	$4	$1	$7	$2	$1	$1	$2	$2

NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and six months ended June 30 was as follows (in millions):

	Alliant Energy				IPL				WPL
	Three Months		Six Months		Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022
Compensation expense	$3	$3	$6	$7	$2	$1	$3	$4	$1	$1	$2	$3
Income tax benefits	1	1	2	2	—	—	1	1	—	—	1	1

As of June 30, 2023, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $15 million, $8 million and $6 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years.

For the six months ended June 30, 2023, performance shares, performance restricted stock units and restricted stock units were granted to key employees under existing plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards.

		Weighted Average
	Grants	Grant Date Fair Value
Performance shares	106,927	$55.68
Performance restricted stock units	122,178	52.77
Restricted stock units	104,849	52.81

As of June 30, 2023, 206,177 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

XML

Derivative Instruments

6 Months Ended

Jun. 30, 2023

Derivative Instruments [Line Items]

Derivative Instruments

DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Notional Amounts - As of June 30, 2023, 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):

	Electricity		FTRs		Natural Gas		Coal
	MWhs	Years	MWhs	Years	Dths	Years	Tons	Years
Alliant Energy	1,171	2023-2025	24,874	2023-2024	192,421	2023-2032	466	2023
IPL	537	2023-2025	10,163	2023-2024	92,087	2023-2030	224	2023
WPL	634	2023-2025	14,711	2023-2024	100,334	2023-2032	242	2023

Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Current derivative assets	$86	$111	$61	$69	$25	$42
Non-current derivative assets	61	126	34	69	27	57
Current derivative liabilities	54	59	27	40	27	19
Non-current derivative liabilities	43	20	10	6	33	14

During the six months ended June 30, 2023, Alliant Energy’s, IPL’s and WPL’s derivative assets decreased primarily due to settlements of natural gas, FTR and electricity contracts and lower natural gas prices, partially offset by new FTRs resulting from the annual FTR auction in the second quarter of 2023 operated by MISO. Alliant Energy’s and WPL’s derivative liabilities increased primarily due to lower natural gas prices. Based on IPL’s and WPL’s cost recovery mechanisms, the changes in the fair value of derivative liabilities/assets resulted in comparable changes to regulatory assets/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 up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At June 30, 2023 and December 31, 2022, 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, derivative assets and derivative liabilities related to commodity contracts would have been presented on the balance sheets as follows (in millions):

	Alliant Energy		IPL		WPL
	Gross		Gross		Gross
	(as reported)	Net	(as reported)	Net	(as reported)	Net
June 30, 2023
Derivative assets	$147	$114	$95	$73	$52	$41
Derivative liabilities	97	64	37	15	60	49
December 31, 2022
Derivative assets	237	193	138	108	99	85
Derivative liabilities	79	35	46	16	33	19

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.

Interest Rate Derivative - In January 2023, AEF entered into a $300 million interest rate swap maturing in January 2026 to mitigate interest rate risk. Under the terms of the swap, AEF exchanged a variable interest rate for a fixed interest rate of 3.93% on a portion of its variable-rate term loan borrowings. The related interest rate derivative was valued based on quoted prices that utilize current market interest rate forecasts. As of June 30, 2023, $4 million of non-current interest rate derivative assets was recorded in “Deferred charges and other” on Alliant Energy’s balance sheet. This interest rate derivative was designated as a cash flow hedge, with changes in fair value recorded as other comprehensive income/loss. As of June 30, 2023, accumulated other comprehensive income included $3 million of income related to the interest rate swap. For the three and six months ended June 30, 2023, $1 million and $1 million, respectively, of reductions to interest expense were recorded in Alliant Energy’s income statement related to the interest rate swap.

IPL [Member]

Derivative Instruments [Line Items]

Derivative Instruments

DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Notional Amounts - As of June 30, 2023, 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):

	Electricity		FTRs		Natural Gas		Coal
	MWhs	Years	MWhs	Years	Dths	Years	Tons	Years
Alliant Energy	1,171	2023-2025	24,874	2023-2024	192,421	2023-2032	466	2023
IPL	537	2023-2025	10,163	2023-2024	92,087	2023-2030	224	2023
WPL	634	2023-2025	14,711	2023-2024	100,334	2023-2032	242	2023

Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Current derivative assets	$86	$111	$61	$69	$25	$42
Non-current derivative assets	61	126	34	69	27	57
Current derivative liabilities	54	59	27	40	27	19
Non-current derivative liabilities	43	20	10	6	33	14

During the six months ended June 30, 2023, Alliant Energy’s, IPL’s and WPL’s derivative assets decreased primarily due to settlements of natural gas, FTR and electricity contracts and lower natural gas prices, partially offset by new FTRs resulting from the annual FTR auction in the second quarter of 2023 operated by MISO. Alliant Energy’s and WPL’s derivative liabilities increased primarily due to lower natural gas prices. Based on IPL’s and WPL’s cost recovery mechanisms, the changes in the fair value of derivative liabilities/assets resulted in comparable changes to regulatory assets/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 up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At June 30, 2023 and December 31, 2022, 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, derivative assets and derivative liabilities related to commodity contracts would have been presented on the balance sheets as follows (in millions):

	Alliant Energy		IPL		WPL
	Gross		Gross		Gross
	(as reported)	Net	(as reported)	Net	(as reported)	Net
June 30, 2023
Derivative assets	$147	$114	$95	$73	$52	$41
Derivative liabilities	97	64	37	15	60	49
December 31, 2022
Derivative assets	237	193	138	108	99	85
Derivative liabilities	79	35	46	16	33	19

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 Instruments [Line Items]

Derivative Instruments

DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Notional Amounts - As of June 30, 2023, 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):

	Electricity		FTRs		Natural Gas		Coal
	MWhs	Years	MWhs	Years	Dths	Years	Tons	Years
Alliant Energy	1,171	2023-2025	24,874	2023-2024	192,421	2023-2032	466	2023
IPL	537	2023-2025	10,163	2023-2024	92,087	2023-2030	224	2023
WPL	634	2023-2025	14,711	2023-2024	100,334	2023-2032	242	2023

Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Current derivative assets	$86	$111	$61	$69	$25	$42
Non-current derivative assets	61	126	34	69	27	57
Current derivative liabilities	54	59	27	40	27	19
Non-current derivative liabilities	43	20	10	6	33	14

During the six months ended June 30, 2023, Alliant Energy’s, IPL’s and WPL’s derivative assets decreased primarily due to settlements of natural gas, FTR and electricity contracts and lower natural gas prices, partially offset by new FTRs resulting from the annual FTR auction in the second quarter of 2023 operated by MISO. Alliant Energy’s and WPL’s derivative liabilities increased primarily due to lower natural gas prices. Based on IPL’s and WPL’s cost recovery mechanisms, the changes in the fair value of derivative liabilities/assets resulted in comparable changes to regulatory assets/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 up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At June 30, 2023 and December 31, 2022, 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, derivative assets and derivative liabilities related to commodity contracts would have been presented on the balance sheets as follows (in millions):

	Alliant Energy		IPL		WPL
	Gross		Gross		Gross
	(as reported)	Net	(as reported)	Net	(as reported)	Net
June 30, 2023
Derivative assets	$147	$114	$95	$73	$52	$41
Derivative liabilities	97	64	37	15	60	49
December 31, 2022
Derivative assets	237	193	138	108	99	85
Derivative liabilities	79	35	46	16	33	19

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.

XML

Fair Value Measurements

6 Months Ended

Jun. 30, 2023

Fair Value Measurements

FAIR VALUE MEASUREMENTS

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 related estimated fair values of other financial instruments were as follows (in millions):

Alliant Energy	June 30, 2023					December 31, 2022
		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	$6	$6	$—	$—	$6	$10	$10	$—	$—	$10
Commodity derivatives	147	—	80	67	147	237	—	206	31	237
Interest rate derivatives	4	—	4	—	4	—	—	—	—	—
Deferred proceeds	175	—	—	175	175	185	—	—	185	185
Liabilities:
Commodity derivatives	97	—	84	13	97	79	—	67	12	79
Long-term debt (incl. current maturities)	8,595	—	7,950	1	7,951	8,076	—	7,338	1	7,339

IPL	June 30, 2023					December 31, 2022
		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	$6	$6	$—	$—	$6	$10	$10	$—	$—	$10
Commodity derivatives	95	—	44	51	95	138	—	111	27	138
Deferred proceeds	175	—	—	175	175	185	—	—	185	185
Liabilities:
Commodity derivatives	37	—	27	10	37	46	—	35	11	46
Long-term debt	3,702	—	3,321	—	3,321	3,646	—	3,228	—	3,228

WPL	June 30, 2023					December 31, 2022
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Commodity derivatives	$52	$—	$36	$16	$52	$99	$—	$95	$4	$99
Liabilities:
Commodity derivatives	60	—	57	3	60	33	—	32	1	33
Long-term debt	3,068	—	2,875	—	2,875	2,770	—	2,542	—	2,542

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
Three Months Ended June 30	2023	2022	2023	2022
Beginning balance, April 1	($5)	$10	$153	$227
Total net losses included in changes in net assets (realized/unrealized)	(7)	(10)	—	—
Purchases	62	79	—	—
Sales	(1)	—	—	—
Settlements (a)	5	(7)	22	17
Ending balance, June 30	$54	$72	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($7)	($10)	$—	$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Six Months Ended June 30	2023	2022	2023	2022
Beginning balance, January 1	$19	$29	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(11)	(16)	—	—
Purchases	62	79	—	—
Sales	(1)	—	—	—
Settlements (a)	(15)	(20)	(10)	30
Ending balance, June 30	$54	$72	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($11)	($16)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Three Months Ended June 30	2023	2022	2023	2022
Beginning balance, April 1	$—	$7	$153	$227
Total net losses included in changes in net assets (realized/unrealized)	(13)	(3)	—	—
Purchases	51	58	—	—
Sales	(1)	—	—	—
Settlements (a)	4	(4)	22	17
Ending balance, June 30	$41	$58	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($13)	($3)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Six Months Ended June 30	2023	2022	2023	2022
Beginning balance, January 1	$16	$18	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(12)	(7)	—	—
Purchases	51	58	—	—
Sales	(1)	—	—	—
Settlements (a)	(13)	(11)	(10)	30
Ending balance, June 30	$41	$58	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($12)	($8)	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Three Months Ended June 30	2023	2022
Beginning balance, April 1	($5)	$3
Total net gains (losses) included in changes in net assets (realized/unrealized)	6	(7)
Purchases	11	21
Settlements	1	(3)
Ending balance, June 30	$13	$14
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 June 30	$6	($7)

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Six Months Ended June 30	2023	2022
Beginning balance, January 1	$3	$11
Total net gains (losses) included in changes in net assets (realized/unrealized)	1	(9)
Purchases	11	21
Settlements	(2)	(9)
Ending balance, June 30	$13	$14
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 June 30	$1	($8)

(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 (liabilities) as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
June 30, 2023	($8)	$62	($5)	$46	($3)	$16
December 31, 2022	(10)	29	(9)	25	(1)	4

IPL [Member]

Fair Value Measurements

FAIR VALUE MEASUREMENTS

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 related estimated fair values of other financial instruments were as follows (in millions):

Alliant Energy	June 30, 2023					December 31, 2022
		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	$6	$6	$—	$—	$6	$10	$10	$—	$—	$10
Commodity derivatives	147	—	80	67	147	237	—	206	31	237
Interest rate derivatives	4	—	4	—	4	—	—	—	—	—
Deferred proceeds	175	—	—	175	175	185	—	—	185	185
Liabilities:
Commodity derivatives	97	—	84	13	97	79	—	67	12	79
Long-term debt (incl. current maturities)	8,595	—	7,950	1	7,951	8,076	—	7,338	1	7,339

IPL	June 30, 2023					December 31, 2022
		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	$6	$6	$—	$—	$6	$10	$10	$—	$—	$10
Commodity derivatives	95	—	44	51	95	138	—	111	27	138
Deferred proceeds	175	—	—	175	175	185	—	—	185	185
Liabilities:
Commodity derivatives	37	—	27	10	37	46	—	35	11	46
Long-term debt	3,702	—	3,321	—	3,321	3,646	—	3,228	—	3,228

WPL	June 30, 2023					December 31, 2022
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Commodity derivatives	$52	$—	$36	$16	$52	$99	$—	$95	$4	$99
Liabilities:
Commodity derivatives	60	—	57	3	60	33	—	32	1	33
Long-term debt	3,068	—	2,875	—	2,875	2,770	—	2,542	—	2,542

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
Three Months Ended June 30	2023	2022	2023	2022
Beginning balance, April 1	($5)	$10	$153	$227
Total net losses included in changes in net assets (realized/unrealized)	(7)	(10)	—	—
Purchases	62	79	—	—
Sales	(1)	—	—	—
Settlements (a)	5	(7)	22	17
Ending balance, June 30	$54	$72	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($7)	($10)	$—	$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Six Months Ended June 30	2023	2022	2023	2022
Beginning balance, January 1	$19	$29	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(11)	(16)	—	—
Purchases	62	79	—	—
Sales	(1)	—	—	—
Settlements (a)	(15)	(20)	(10)	30
Ending balance, June 30	$54	$72	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($11)	($16)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Three Months Ended June 30	2023	2022	2023	2022
Beginning balance, April 1	$—	$7	$153	$227
Total net losses included in changes in net assets (realized/unrealized)	(13)	(3)	—	—
Purchases	51	58	—	—
Sales	(1)	—	—	—
Settlements (a)	4	(4)	22	17
Ending balance, June 30	$41	$58	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($13)	($3)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Six Months Ended June 30	2023	2022	2023	2022
Beginning balance, January 1	$16	$18	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(12)	(7)	—	—
Purchases	51	58	—	—
Sales	(1)	—	—	—
Settlements (a)	(13)	(11)	(10)	30
Ending balance, June 30	$41	$58	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($12)	($8)	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Three Months Ended June 30	2023	2022
Beginning balance, April 1	($5)	$3
Total net gains (losses) included in changes in net assets (realized/unrealized)	6	(7)
Purchases	11	21
Settlements	1	(3)
Ending balance, June 30	$13	$14
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 June 30	$6	($7)

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Six Months Ended June 30	2023	2022
Beginning balance, January 1	$3	$11
Total net gains (losses) included in changes in net assets (realized/unrealized)	1	(9)
Purchases	11	21
Settlements	(2)	(9)
Ending balance, June 30	$13	$14
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 June 30	$1	($8)

(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 (liabilities) as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
June 30, 2023	($8)	$62	($5)	$46	($3)	$16
December 31, 2022	(10)	29	(9)	25	(1)	4

WPL [Member]

Fair Value Measurements

FAIR VALUE MEASUREMENTS

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 related estimated fair values of other financial instruments were as follows (in millions):

Alliant Energy	June 30, 2023					December 31, 2022
		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	$6	$6	$—	$—	$6	$10	$10	$—	$—	$10
Commodity derivatives	147	—	80	67	147	237	—	206	31	237
Interest rate derivatives	4	—	4	—	4	—	—	—	—	—
Deferred proceeds	175	—	—	175	175	185	—	—	185	185
Liabilities:
Commodity derivatives	97	—	84	13	97	79	—	67	12	79
Long-term debt (incl. current maturities)	8,595	—	7,950	1	7,951	8,076	—	7,338	1	7,339

IPL	June 30, 2023					December 31, 2022
		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	$6	$6	$—	$—	$6	$10	$10	$—	$—	$10
Commodity derivatives	95	—	44	51	95	138	—	111	27	138
Deferred proceeds	175	—	—	175	175	185	—	—	185	185
Liabilities:
Commodity derivatives	37	—	27	10	37	46	—	35	11	46
Long-term debt	3,702	—	3,321	—	3,321	3,646	—	3,228	—	3,228

WPL	June 30, 2023					December 31, 2022
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Commodity derivatives	$52	$—	$36	$16	$52	$99	$—	$95	$4	$99
Liabilities:
Commodity derivatives	60	—	57	3	60	33	—	32	1	33
Long-term debt	3,068	—	2,875	—	2,875	2,770	—	2,542	—	2,542

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
Three Months Ended June 30	2023	2022	2023	2022
Beginning balance, April 1	($5)	$10	$153	$227
Total net losses included in changes in net assets (realized/unrealized)	(7)	(10)	—	—
Purchases	62	79	—	—
Sales	(1)	—	—	—
Settlements (a)	5	(7)	22	17
Ending balance, June 30	$54	$72	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($7)	($10)	$—	$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Six Months Ended June 30	2023	2022	2023	2022
Beginning balance, January 1	$19	$29	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(11)	(16)	—	—
Purchases	62	79	—	—
Sales	(1)	—	—	—
Settlements (a)	(15)	(20)	(10)	30
Ending balance, June 30	$54	$72	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($11)	($16)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Three Months Ended June 30	2023	2022	2023	2022
Beginning balance, April 1	$—	$7	$153	$227
Total net losses included in changes in net assets (realized/unrealized)	(13)	(3)	—	—
Purchases	51	58	—	—
Sales	(1)	—	—	—
Settlements (a)	4	(4)	22	17
Ending balance, June 30	$41	$58	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($13)	($3)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Six Months Ended June 30	2023	2022	2023	2022
Beginning balance, January 1	$16	$18	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(12)	(7)	—	—
Purchases	51	58	—	—
Sales	(1)	—	—	—
Settlements (a)	(13)	(11)	(10)	30
Ending balance, June 30	$41	$58	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($12)	($8)	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Three Months Ended June 30	2023	2022
Beginning balance, April 1	($5)	$3
Total net gains (losses) included in changes in net assets (realized/unrealized)	6	(7)
Purchases	11	21
Settlements	1	(3)
Ending balance, June 30	$13	$14
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 June 30	$6	($7)

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Six Months Ended June 30	2023	2022
Beginning balance, January 1	$3	$11
Total net gains (losses) included in changes in net assets (realized/unrealized)	1	(9)
Purchases	11	21
Settlements	(2)	(9)
Ending balance, June 30	$13	$14
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 June 30	$1	($8)

(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 (liabilities) as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
June 30, 2023	($8)	$62	($5)	$46	($3)	$16
December 31, 2022	(10)	29	(9)	25	(1)	4

XML

Commitments And Contingencies

6 Months Ended

Jun. 30, 2023

Commitments and Contingencies Disclosure

COMMITMENTS AND CONTINGENCIESNOTE 13(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects, including IPL’s and WPL’s expansion of solar generation. At June 30, 2023, Alliant Energy’s, IPL’s and WPL’s minimum future commitments for these projects were $188 million, $87 million and $101 million, respectively.

NOTE 13(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 June 30, 2023, related minimum future commitments were as follows (in millions):

	Alliant Energy	IPL	WPL
Natural gas	$1,083	$494	$589
Coal	163	79	84
Other (a)	106	51	25
	$1,352	$624	$698

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2023.

NOTE 13(c) 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 June 30, 2023, the currently known partnership obligations for the abandonment obligations are estimated at $58 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 $58 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 June 30, 2023 and December 31, 2022, 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.

Whiting Petroleum completed a business combination with Oasis Petroleum Inc. in July 2022. The combined operations are now known as Chord Energy Corporation. The business combination is not expected to affect the scope of the Whiting Petroleum affiliate’s obligations to Alliant Energy or Alliant Energy’s related 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 $59 million as of June 30, 2023 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 June 30, 2023 and December 31, 2022.

NOTE 13(d) Environmental Matters -

Manufactured Gas Plant (MGP) 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 June 30, 2023, 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):

	Alliant Energy			IPL			WPL
Range of estimated future costs	$9	-	$36	$5	-	$11	$4	-	$25
Current and non-current environmental liabilities	$18			$8			$10

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 Clean Air Act 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: Cross-State Air Pollution Rule, Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including the Clean Air Act.

NOTE 13(e) MISO Transmission Owner Return on Equity Complaints - A group of stakeholders, including MISO cooperative and municipal utilities, previously filed complaints with the Federal Energy Regulatory Commission (FERC) requesting a reduction to the base return on equity authorized for MISO transmission owners, including ITC Midwest LLC and ATC. In 2019, FERC issued an order on the previously filed complaints and reduced the base return on equity authorized for the MISO transmission owners to 9.88% for November 12, 2013 through February 11, 2015, and subsequent to September 28, 2016. In 2020, FERC issued orders in response to various rehearing requests and increased the base return on equity authorized for the MISO transmission owners from 9.88% to 10.02% for November 12, 2013 through February 11, 2015, and subsequent to September 28, 2016. In August 2022, the U.S. Court of Appeals for the District of Columbia Circuit vacated FERC’s prior orders that established the base return on equity authorized for the MISO transmission owners and remanded the cases to FERC for further proceedings, which may result in additional changes to the base return on equity authorized for the MISO transmission owners. Any further changes in FERC’s decisions may have an impact on Alliant Energy’s share of ATC’s future earnings and customer costs.

IPL [Member]

Commitments and Contingencies Disclosure

COMMITMENTS AND CONTINGENCIESNOTE 13(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects, including IPL’s and WPL’s expansion of solar generation. At June 30, 2023, Alliant Energy’s, IPL’s and WPL’s minimum future commitments for these projects were $188 million, $87 million and $101 million, respectively.

NOTE 13(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 June 30, 2023, related minimum future commitments were as follows (in millions):

	Alliant Energy	IPL	WPL
Natural gas	$1,083	$494	$589
Coal	163	79	84
Other (a)	106	51	25
	$1,352	$624	$698

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2023.

NOTE 13(c) 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 June 30, 2023, the currently known partnership obligations for the abandonment obligations are estimated at $58 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 $58 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 June 30, 2023 and December 31, 2022, 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.

Whiting Petroleum completed a business combination with Oasis Petroleum Inc. in July 2022. The combined operations are now known as Chord Energy Corporation. The business combination is not expected to affect the scope of the Whiting Petroleum affiliate’s obligations to Alliant Energy or Alliant Energy’s related 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 $59 million as of June 30, 2023 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 June 30, 2023 and December 31, 2022.

NOTE 13(d) Environmental Matters -

Manufactured Gas Plant (MGP) 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 June 30, 2023, 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):

	Alliant Energy			IPL			WPL
Range of estimated future costs	$9	-	$36	$5	-	$11	$4	-	$25
Current and non-current environmental liabilities	$18			$8			$10

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 Clean Air Act 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: Cross-State Air Pollution Rule, Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including the Clean Air Act.

NOTE 13(e) MISO Transmission Owner Return on Equity Complaints - A group of stakeholders, including MISO cooperative and municipal utilities, previously filed complaints with the Federal Energy Regulatory Commission (FERC) requesting a reduction to the base return on equity authorized for MISO transmission owners, including ITC Midwest LLC and ATC. In 2019, FERC issued an order on the previously filed complaints and reduced the base return on equity authorized for the MISO transmission owners to 9.88% for November 12, 2013 through February 11, 2015, and subsequent to September 28, 2016. In 2020, FERC issued orders in response to various rehearing requests and increased the base return on equity authorized for the MISO transmission owners from 9.88% to 10.02% for November 12, 2013 through February 11, 2015, and subsequent to September 28, 2016. In August 2022, the U.S. Court of Appeals for the District of Columbia Circuit vacated FERC’s prior orders that established the base return on equity authorized for the MISO transmission owners and remanded the cases to FERC for further proceedings, which may result in additional changes to the base return on equity authorized for the MISO transmission owners. Any further changes in FERC’s decisions may have an impact on Alliant Energy’s share of ATC’s future earnings and customer costs.

WPL [Member]

Commitments and Contingencies Disclosure

COMMITMENTS AND CONTINGENCIESNOTE 13(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects, including IPL’s and WPL’s expansion of solar generation. At June 30, 2023, Alliant Energy’s, IPL’s and WPL’s minimum future commitments for these projects were $188 million, $87 million and $101 million, respectively.

NOTE 13(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 June 30, 2023, related minimum future commitments were as follows (in millions):

	Alliant Energy	IPL	WPL
Natural gas	$1,083	$494	$589
Coal	163	79	84
Other (a)	106	51	25
	$1,352	$624	$698

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2023.

NOTE 13(c) 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 June 30, 2023, the currently known partnership obligations for the abandonment obligations are estimated at $58 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 $58 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 June 30, 2023 and December 31, 2022, 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.

Whiting Petroleum completed a business combination with Oasis Petroleum Inc. in July 2022. The combined operations are now known as Chord Energy Corporation. The business combination is not expected to affect the scope of the Whiting Petroleum affiliate’s obligations to Alliant Energy or Alliant Energy’s related 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 $59 million as of June 30, 2023 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 June 30, 2023 and December 31, 2022.

NOTE 13(d) Environmental Matters -

Manufactured Gas Plant (MGP) 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 June 30, 2023, 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):

	Alliant Energy			IPL			WPL
Range of estimated future costs	$9	-	$36	$5	-	$11	$4	-	$25
Current and non-current environmental liabilities	$18			$8			$10

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 Clean Air Act 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: Cross-State Air Pollution Rule, Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including the Clean Air Act.

NOTE 13(e) MISO Transmission Owner Return on Equity Complaints - A group of stakeholders, including MISO cooperative and municipal utilities, previously filed complaints with the Federal Energy Regulatory Commission (FERC) requesting a reduction to the base return on equity authorized for MISO transmission owners, including ITC Midwest LLC and ATC. In 2019, FERC issued an order on the previously filed complaints and reduced the base return on equity authorized for the MISO transmission owners to 9.88% for November 12, 2013 through February 11, 2015, and subsequent to September 28, 2016. In 2020, FERC issued orders in response to various rehearing requests and increased the base return on equity authorized for the MISO transmission owners from 9.88% to 10.02% for November 12, 2013 through February 11, 2015, and subsequent to September 28, 2016. In August 2022, the U.S. Court of Appeals for the District of Columbia Circuit vacated FERC’s prior orders that established the base return on equity authorized for the MISO transmission owners and remanded the cases to FERC for further proceedings, which may result in additional changes to the base return on equity authorized for the MISO transmission owners. Any further changes in FERC’s decisions may have an impact on Alliant Energy’s share of ATC’s future earnings and customer costs.

XML

Segments Of Business

6 Months Ended

Jun. 30, 2023

Segment Reporting Information [Line Items]

Segments Of Business

SEGMENTS OF BUSINESS

Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s business segments is as follows. Intersegment revenues were not material to their respective operations.

Alliant Energy					ATC Holdings,	Alliant
	Utility				Non-Utility,	Energy
	Electric	Gas	Other	Total	Parent and Other	Consolidated
	(in millions)
Three Months Ended June 30, 2023
Revenues	$799	$77	$13	$889	$23	$912
Operating income	200	2	7	209	8	217
Net income (loss) attributable to Alliant Energy common shareowners				161	(1)	160
Three Months Ended June 30, 2022
Revenues	$812	$94	$13	$919	$24	$943
Operating income	195	8	1	204	8	212
Net income attributable to Alliant Energy common shareowners				150	9	159

Alliant Energy					ATC Holdings,	Alliant
	Utility				Non-Utility,	Energy
	Electric	Gas	Other	Total	Parent and Other	Consolidated
	(in millions)
Six Months Ended June 30, 2023
Revenues	$1,567	$353	$25	$1,945	$45	$1,990
Operating income	363	52	11	426	13	439
Net income attributable to Alliant Energy common shareowners				321	2	323
Six Months Ended June 30, 2022
Revenues	$1,586	$356	$23	$1,965	$47	$2,012
Operating income	376	65	4	445	15	460
Net income attributable to Alliant Energy common shareowners				329	22	351

IPL	Electric	Gas	Other	Total
	(in millions)
Three Months Ended June 30, 2023
Revenues	$431	$44	$12	$487
Operating income	105	—	5	110
Net income				89
Three Months Ended June 30, 2022
Revenues	$442	$52	$12	$506
Operating income	104	4	1	109
Net income				87
Six Months Ended June 30, 2023
Revenues	$819	$194	$24	$1,037
Operating income	171	27	8	206
Net income				161
Six Months Ended June 30, 2022
Revenues	$843	$191	$22	$1,056
Operating income	179	36	3	218
Net income				173

WPL	Electric	Gas	Other	Total
	(in millions)
Three Months Ended June 30, 2023
Revenues	$368	$33	$1	$402
Operating income	95	2	2	99
Net income				72
Three Months Ended June 30, 2022
Revenues	$370	$42	$1	$413
Operating income	91	4	—	95
Net income				63
Six Months Ended June 30, 2023
Revenues	$748	$159	$1	$908
Operating income	192	25	3	220
Net income				160
Six Months Ended June 30, 2022
Revenues	$743	$165	$1	$909
Operating income	197	29	1	227
Net income				156

IPL [Member]

Segment Reporting Information [Line Items]

Segments Of Business

SEGMENTS OF BUSINESS

Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s business segments is as follows. Intersegment revenues were not material to their respective operations.

Alliant Energy					ATC Holdings,	Alliant
	Utility				Non-Utility,	Energy
	Electric	Gas	Other	Total	Parent and Other	Consolidated
	(in millions)
Three Months Ended June 30, 2023
Revenues	$799	$77	$13	$889	$23	$912
Operating income	200	2	7	209	8	217
Net income (loss) attributable to Alliant Energy common shareowners				161	(1)	160
Three Months Ended June 30, 2022
Revenues	$812	$94	$13	$919	$24	$943
Operating income	195	8	1	204	8	212
Net income attributable to Alliant Energy common shareowners				150	9	159

Alliant Energy					ATC Holdings,	Alliant
	Utility				Non-Utility,	Energy
	Electric	Gas	Other	Total	Parent and Other	Consolidated
	(in millions)
Six Months Ended June 30, 2023
Revenues	$1,567	$353	$25	$1,945	$45	$1,990
Operating income	363	52	11	426	13	439
Net income attributable to Alliant Energy common shareowners				321	2	323
Six Months Ended June 30, 2022
Revenues	$1,586	$356	$23	$1,965	$47	$2,012
Operating income	376	65	4	445	15	460
Net income attributable to Alliant Energy common shareowners				329	22	351

IPL	Electric	Gas	Other	Total
	(in millions)
Three Months Ended June 30, 2023
Revenues	$431	$44	$12	$487
Operating income	105	—	5	110
Net income				89
Three Months Ended June 30, 2022
Revenues	$442	$52	$12	$506
Operating income	104	4	1	109
Net income				87
Six Months Ended June 30, 2023
Revenues	$819	$194	$24	$1,037
Operating income	171	27	8	206
Net income				161
Six Months Ended June 30, 2022
Revenues	$843	$191	$22	$1,056
Operating income	179	36	3	218
Net income				173

WPL	Electric	Gas	Other	Total
	(in millions)
Three Months Ended June 30, 2023
Revenues	$368	$33	$1	$402
Operating income	95	2	2	99
Net income				72
Three Months Ended June 30, 2022
Revenues	$370	$42	$1	$413
Operating income	91	4	—	95
Net income				63
Six Months Ended June 30, 2023
Revenues	$748	$159	$1	$908
Operating income	192	25	3	220
Net income				160
Six Months Ended June 30, 2022
Revenues	$743	$165	$1	$909
Operating income	197	29	1	227
Net income				156

WPL [Member]

Segment Reporting Information [Line Items]

Segments Of Business

SEGMENTS OF BUSINESS

Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s business segments is as follows. Intersegment revenues were not material to their respective operations.

Alliant Energy					ATC Holdings,	Alliant
	Utility				Non-Utility,	Energy
	Electric	Gas	Other	Total	Parent and Other	Consolidated
	(in millions)
Three Months Ended June 30, 2023
Revenues	$799	$77	$13	$889	$23	$912
Operating income	200	2	7	209	8	217
Net income (loss) attributable to Alliant Energy common shareowners				161	(1)	160
Three Months Ended June 30, 2022
Revenues	$812	$94	$13	$919	$24	$943
Operating income	195	8	1	204	8	212
Net income attributable to Alliant Energy common shareowners				150	9	159

Alliant Energy					ATC Holdings,	Alliant
	Utility				Non-Utility,	Energy
	Electric	Gas	Other	Total	Parent and Other	Consolidated
	(in millions)
Six Months Ended June 30, 2023
Revenues	$1,567	$353	$25	$1,945	$45	$1,990
Operating income	363	52	11	426	13	439
Net income attributable to Alliant Energy common shareowners				321	2	323
Six Months Ended June 30, 2022
Revenues	$1,586	$356	$23	$1,965	$47	$2,012
Operating income	376	65	4	445	15	460
Net income attributable to Alliant Energy common shareowners				329	22	351

IPL	Electric	Gas	Other	Total
	(in millions)
Three Months Ended June 30, 2023
Revenues	$431	$44	$12	$487
Operating income	105	—	5	110
Net income				89
Three Months Ended June 30, 2022
Revenues	$442	$52	$12	$506
Operating income	104	4	1	109
Net income				87
Six Months Ended June 30, 2023
Revenues	$819	$194	$24	$1,037
Operating income	171	27	8	206
Net income				161
Six Months Ended June 30, 2022
Revenues	$843	$191	$22	$1,056
Operating income	179	36	3	218
Net income				173

WPL	Electric	Gas	Other	Total
	(in millions)
Three Months Ended June 30, 2023
Revenues	$368	$33	$1	$402
Operating income	95	2	2	99
Net income				72
Three Months Ended June 30, 2022
Revenues	$370	$42	$1	$413
Operating income	91	4	—	95
Net income				63
Six Months Ended June 30, 2023
Revenues	$748	$159	$1	$908
Operating income	192	25	3	220
Net income				160
Six Months Ended June 30, 2022
Revenues	$743	$165	$1	$909
Operating income	197	29	1	227
Net income				156

XML

Related Parties

6 Months Ended

Jun. 30, 2023

Related Party Transactions [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 for the three and six months ended June 30 were as follows (in millions):

	IPL				WPL
	Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022
Corporate Services billings	$48	$51	$88	$91	$43	$42	$80	$78
Sales credited	1	—	8	—	10	13	22	31
Purchases billed	94	129	187	223	2	39	17	61

Net intercompany payables to Corporate Services were as follows (in millions):

	IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Net payables to Corporate Services	$116	$103	$73	$56

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 for the three and six months ended June 30 were as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
ATC billings to WPL	$44	$35	$78	$69
WPL billings to ATC	5	5	11	8

WPL owed ATC net amounts of $10 million as of June 30, 2023 and $10 million as of December 31, 2022.

IPL [Member]

Related Party Transactions [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 for the three and six months ended June 30 were as follows (in millions):

	IPL				WPL
	Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022
Corporate Services billings	$48	$51	$88	$91	$43	$42	$80	$78
Sales credited	1	—	8	—	10	13	22	31
Purchases billed	94	129	187	223	2	39	17	61

Net intercompany payables to Corporate Services were as follows (in millions):

	IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Net payables to Corporate Services	$116	$103	$73	$56

WPL [Member]

Related Party Transactions [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 for the three and six months ended June 30 were as follows (in millions):

	IPL				WPL
	Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022
Corporate Services billings	$48	$51	$88	$91	$43	$42	$80	$78
Sales credited	1	—	8	—	10	13	22	31
Purchases billed	94	129	187	223	2	39	17	61

Net intercompany payables to Corporate Services were as follows (in millions):

	IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Net payables to Corporate Services	$116	$103	$73	$56

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 for the three and six months ended June 30 were as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
ATC billings to WPL	$44	$35	$78	$69
WPL billings to ATC	5	5	11	8

WPL owed ATC net amounts of $10 million as of June 30, 2023 and $10 million as of December 31, 2022.

XML

Pay vs Performance Disclosure - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Pay vs Performance Disclosure
Net income	$ 323	$ 351

XML

Insider Trading Arrangements	3 Months Ended
	Jun. 30, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

XML

Summary Of Significant Accounting Policies (Policy)	6 Months Ended
	Jun. 30, 2023
General, Basis of Accounting	The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the SEC. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the 2022 Form 10-K.In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the six months ended June 30, 2023 are not necessarily indicative of results that may be expected for the year ending December 31, 2023.
General, Use of Estimates	A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred.
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.
IPL [Member]
General, Basis of Accounting	The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the SEC. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the 2022 Form 10-K.In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the six months ended June 30, 2023 are not necessarily indicative of results that may be expected for the year ending December 31, 2023.
General, Use of Estimates	A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred.
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.
WPL [Member]
General, Basis of Accounting	The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the SEC. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the 2022 Form 10-K.In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the six months ended June 30, 2023 are not necessarily indicative of results that may be expected for the year ending December 31, 2023.
General, Use of Estimates	A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred.
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.

XML

Regulatory Matters (Tables)

6 Months Ended

Jun. 30, 2023

Regulatory Assets [Line Items]

Regulatory Assets

Regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$957	$929	$868	$848	$89	$81
Pension and OPEB costs	378	392	190	197	188	195
Assets retired early	290	70	274	53	16	17
Asset retirement obligations	197	151	156	110	41	41
Commodity cost recovery	145	160	6	1	139	159
Derivatives	102	84	41	48	61	36
IPL’s Duane Arnold Energy Center PPA amendment	54	66	54	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	47	48	—	—	47	48
Other	174	146	59	63	115	83
	$2,344	$2,046	$1,648	$1,386	$696	$660

Regulatory Liabilities

Regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$572	$579	$301	$303	$271	$276
Cost of removal obligations	405	398	260	259	145	139
Derivatives	90	210	48	115	42	95
Commodity cost recovery	39	40	15	38	24	2
Electric transmission cost recovery	19	20	14	10	5	10
WPL’s West Riverside liquidated damages	17	32	—	—	17	32
Other	66	45	38	29	28	16
	$1,208	$1,324	$676	$754	$532	$570

IPL [Member]

Regulatory Assets [Line Items]

Regulatory Assets

Regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$957	$929	$868	$848	$89	$81
Pension and OPEB costs	378	392	190	197	188	195
Assets retired early	290	70	274	53	16	17
Asset retirement obligations	197	151	156	110	41	41
Commodity cost recovery	145	160	6	1	139	159
Derivatives	102	84	41	48	61	36
IPL’s Duane Arnold Energy Center PPA amendment	54	66	54	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	47	48	—	—	47	48
Other	174	146	59	63	115	83
	$2,344	$2,046	$1,648	$1,386	$696	$660

Regulatory Liabilities

Regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$572	$579	$301	$303	$271	$276
Cost of removal obligations	405	398	260	259	145	139
Derivatives	90	210	48	115	42	95
Commodity cost recovery	39	40	15	38	24	2
Electric transmission cost recovery	19	20	14	10	5	10
WPL’s West Riverside liquidated damages	17	32	—	—	17	32
Other	66	45	38	29	28	16
	$1,208	$1,324	$676	$754	$532	$570

WPL [Member]

Regulatory Assets [Line Items]

Regulatory Assets

Regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$957	$929	$868	$848	$89	$81
Pension and OPEB costs	378	392	190	197	188	195
Assets retired early	290	70	274	53	16	17
Asset retirement obligations	197	151	156	110	41	41
Commodity cost recovery	145	160	6	1	139	159
Derivatives	102	84	41	48	61	36
IPL’s Duane Arnold Energy Center PPA amendment	54	66	54	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	47	48	—	—	47	48
Other	174	146	59	63	115	83
	$2,344	$2,046	$1,648	$1,386	$696	$660

Regulatory Liabilities

Regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$572	$579	$301	$303	$271	$276
Cost of removal obligations	405	398	260	259	145	139
Derivatives	90	210	48	115	42	95
Commodity cost recovery	39	40	15	38	24	2
Electric transmission cost recovery	19	20	14	10	5	10
WPL’s West Riverside liquidated damages	17	32	—	—	17	32
Other	66	45	38	29	28	16
	$1,208	$1,324	$676	$754	$532	$570

XML

Receivables (Tables)

6 Months Ended

Jun. 30, 2023

Receivables [Line Items]

Gross Write-offs For Accounts Receivable

For the three and six months ended June 30, 2023, Alliant Energy’s, IPL’s and WPL’s gross write-offs for accounts receivable were as follows (in millions):

	Originated in 2022		Originated in 2023
	Three Months	Six Months	Three Months	Six Months
Alliant Energy	$3	$8	$2	$2
IPL	2	5	1	1
WPL	1	3	1	1

Maximum And Average Outstanding Cash Proceeds

IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and six months ended June 30 were as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
Maximum outstanding aggregate cash proceeds	$110	$66	$110	$66
Average outstanding aggregate cash proceeds	101	18	79	11

Attributes of Receivables Sold Under the Receivables Agreement

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

	June 30, 2023	December 31, 2022
Customer accounts receivable	$148	$145
Unbilled utility revenues	100	132
Receivables sold to third party	248	277
Less: cash proceeds	60	80
Deferred proceeds	188	197
Less: allowance for expected credit losses	13	12
Fair value of deferred proceeds	$175	$185

Additional Attributes Of Receivables Sold Under The Receivables Agreement

Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and six months ended June 30 were as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
Collections	$514	$500	$1,104	$1,061
Write-offs, net of recoveries	2	1	4	3

IPL [Member]

Receivables [Line Items]

Gross Write-offs For Accounts Receivable

For the three and six months ended June 30, 2023, Alliant Energy’s, IPL’s and WPL’s gross write-offs for accounts receivable were as follows (in millions):

	Originated in 2022		Originated in 2023
	Three Months	Six Months	Three Months	Six Months
Alliant Energy	$3	$8	$2	$2
IPL	2	5	1	1
WPL	1	3	1	1

Maximum And Average Outstanding Cash Proceeds

IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and six months ended June 30 were as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
Maximum outstanding aggregate cash proceeds	$110	$66	$110	$66
Average outstanding aggregate cash proceeds	101	18	79	11

Attributes of Receivables Sold Under the Receivables Agreement

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

	June 30, 2023	December 31, 2022
Customer accounts receivable	$148	$145
Unbilled utility revenues	100	132
Receivables sold to third party	248	277
Less: cash proceeds	60	80
Deferred proceeds	188	197
Less: allowance for expected credit losses	13	12
Fair value of deferred proceeds	$175	$185

Additional Attributes Of Receivables Sold Under The Receivables Agreement

Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and six months ended June 30 were as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
Collections	$514	$500	$1,104	$1,061
Write-offs, net of recoveries	2	1	4	3

WPL [Member]

Receivables [Line Items]

Gross Write-offs For Accounts Receivable

For the three and six months ended June 30, 2023, Alliant Energy’s, IPL’s and WPL’s gross write-offs for accounts receivable were as follows (in millions):

	Originated in 2022		Originated in 2023
	Three Months	Six Months	Three Months	Six Months
Alliant Energy	$3	$8	$2	$2
IPL	2	5	1	1
WPL	1	3	1	1

XML

Investments (Tables)

6 Months Ended

Jun. 30, 2023

Schedule of Equity Method Investments [Line Items]

Unconsolidated Equity Investments

Alliant Energy’s equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three and six months ended June 30 was as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
ATC Holdings	($12)	($11)	($25)	($23)
Other	(2)	(5)	(6)	(9)
	($14)	($16)	($31)	($32)

XML

Common Equity (Tables)

6 Months Ended

Jun. 30, 2023

Schedule of Capitalization, Equity [Line Items]

Common Share Activity

A summary of Alliant Energy’s common stock activity was as follows:

Shares outstanding, January 1, 2023	251,134,966
At-the-market offering program	1,221,775
Shareowner Direct Plan	228,017
Equity-based compensation plans	134,334
Shares outstanding, June 30, 2023	252,719,092

Changes in Shareowners' Equity

A summary of changes in shareowners’ equity was as follows (in millions):

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in
		Additional		Other	Deferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Noncontrolling	Total
	Stock	Capital	Earnings	Income (Loss)	Trust	Interest	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$3	$2,780	$3,559	($1)	($13)	$—	$6,328
Net income attributable to Alliant Energy common shareowners			160				160
Common stock dividends ($0.4525 per share)			(113)				(113)
At-the-market offering program and Shareowner Direct Plan issuances		70					70
Equity-based compensation plans and other		4			(1)		3
Other comprehensive income, net of tax				4			4
Ending balance, June 30, 2023	$3	$2,854	$3,606	$3	($14)	$—	$6,452
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$3	$2,750	$3,336	$—	($12)	$—	$6,077
Net income attributable to Alliant Energy common shareowners			159				159
Common stock dividends ($0.4275 per share)			(108)				(108)
Shareowner Direct Plan issuances		6					6
Equity-based compensation plans and other		3					3
Contributions from noncontrolling interest						29	29
Ending balance, June 30, 2022	$3	$2,759	$3,387	$—	($12)	$29	$6,166

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in
		Additional		Other	Deferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Noncontrolling	Total
	Stock	Capital	Earnings	Income (Loss)	Trust	Interest	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$3	$2,777	$3,509	$—	($13)	$—	$6,276
Net income attributable to Alliant Energy common shareowners			323				323
Common stock dividends ($0.905 per share)			(226)				(226)
At-the-market offering program and Shareowner Direct Plan issuances		76					76
Equity-based compensation plans and other		1			(1)		—
Other comprehensive income, net of tax				3			3
Ending balance, June 30, 2023	$3	$2,854	$3,606	$3	($14)	$—	$6,452
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$3	$2,749	$3,250	$—	($12)	$—	$5,990
Net income attributable to Alliant Energy common shareowners			351				351
Common stock dividends ($0.855 per share)			(215)				(215)
Shareowner Direct Plan issuances		13					13
Equity-based compensation plans and other		(3)	1				(2)
Contributions from noncontrolling interest						29	29
Ending balance, June 30, 2022	$3	$2,759	$3,387	$—	($12)	$29	$6,166

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$33	$2,807	$970	$3,810
Net income			89	89
Common stock dividends			(70)	(70)
Capital contributions from parent		40		40
Ending balance, June 30, 2023	$33	$2,847	$989	$3,869
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$33	$2,807	$935	$3,775
Net income			87	87
Common stock dividends			(80)	(80)
Ending balance, June 30, 2022	$33	$2,807	$942	$3,782

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$33	$2,807	$968	$3,808
Net income			161	161
Common stock dividends			(140)	(140)
Capital contributions from parent		40		40
Ending balance, June 30, 2023	$33	$2,847	$989	$3,869
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$33	$2,807	$929	$3,769
Net income			173	173
Common stock dividends			(160)	(160)
Ending balance, June 30, 2022	$33	$2,807	$942	$3,782

WPL	Total WPL Common Equity
		Additional
	Common	Paid-In	Retained	Noncontrolling	Total
	Stock	Capital	Earnings	Interest	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$66	$2,413	$1,234	$—	$3,713
Net income			72		72
Common stock dividends			(46)		(46)
Ending balance, June 30, 2023	$66	$2,413	$1,260	$—	$3,739
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$66	$1,884	$1,101	$—	$3,051
Net income			63		63
Common stock dividends			(44)		(44)
Capital contributions from parent		85			85
Contributions from noncontrolling interest				29	29
Other		(1)			(1)
Ending balance, June 30, 2022	$66	$1,968	$1,120	$29	$3,183

WPL	Total WPL Common Equity
		Additional
	Common	Paid-In	Retained	Noncontrolling	Total
	Stock	Capital	Earnings	Interest	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$66	$2,233	$1,192	$—	$3,491
Net income			160		160
Common stock dividends			(92)		(92)
Capital contributions from parent		180			180
Ending balance, June 30, 2023	$66	$2,413	$1,260	$—	$3,739
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$66	$1,704	$1,053	$—	$2,823
Net income			156		156
Common stock dividends			(89)		(89)
Capital contributions from parent		265			265
Contributions from noncontrolling interest				29	29
Other		(1)			(1)
Ending balance, June 30, 2022	$66	$1,968	$1,120	$29	$3,183

IPL [Member]

Schedule of Capitalization, Equity [Line Items]

Changes in Shareowners' Equity

A summary of changes in shareowners’ equity was as follows (in millions):

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in
		Additional		Other	Deferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Noncontrolling	Total
	Stock	Capital	Earnings	Income (Loss)	Trust	Interest	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$3	$2,780	$3,559	($1)	($13)	$—	$6,328
Net income attributable to Alliant Energy common shareowners			160				160
Common stock dividends ($0.4525 per share)			(113)				(113)
At-the-market offering program and Shareowner Direct Plan issuances		70					70
Equity-based compensation plans and other		4			(1)		3
Other comprehensive income, net of tax				4			4
Ending balance, June 30, 2023	$3	$2,854	$3,606	$3	($14)	$—	$6,452
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$3	$2,750	$3,336	$—	($12)	$—	$6,077
Net income attributable to Alliant Energy common shareowners			159				159
Common stock dividends ($0.4275 per share)			(108)				(108)
Shareowner Direct Plan issuances		6					6
Equity-based compensation plans and other		3					3
Contributions from noncontrolling interest						29	29
Ending balance, June 30, 2022	$3	$2,759	$3,387	$—	($12)	$29	$6,166

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in
		Additional		Other	Deferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Noncontrolling	Total
	Stock	Capital	Earnings	Income (Loss)	Trust	Interest	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$3	$2,777	$3,509	$—	($13)	$—	$6,276
Net income attributable to Alliant Energy common shareowners			323				323
Common stock dividends ($0.905 per share)			(226)				(226)
At-the-market offering program and Shareowner Direct Plan issuances		76					76
Equity-based compensation plans and other		1			(1)		—
Other comprehensive income, net of tax				3			3
Ending balance, June 30, 2023	$3	$2,854	$3,606	$3	($14)	$—	$6,452
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$3	$2,749	$3,250	$—	($12)	$—	$5,990
Net income attributable to Alliant Energy common shareowners			351				351
Common stock dividends ($0.855 per share)			(215)				(215)
Shareowner Direct Plan issuances		13					13
Equity-based compensation plans and other		(3)	1				(2)
Contributions from noncontrolling interest						29	29
Ending balance, June 30, 2022	$3	$2,759	$3,387	$—	($12)	$29	$6,166

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$33	$2,807	$970	$3,810
Net income			89	89
Common stock dividends			(70)	(70)
Capital contributions from parent		40		40
Ending balance, June 30, 2023	$33	$2,847	$989	$3,869
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$33	$2,807	$935	$3,775
Net income			87	87
Common stock dividends			(80)	(80)
Ending balance, June 30, 2022	$33	$2,807	$942	$3,782

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$33	$2,807	$968	$3,808
Net income			161	161
Common stock dividends			(140)	(140)
Capital contributions from parent		40		40
Ending balance, June 30, 2023	$33	$2,847	$989	$3,869
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$33	$2,807	$929	$3,769
Net income			173	173
Common stock dividends			(160)	(160)
Ending balance, June 30, 2022	$33	$2,807	$942	$3,782

WPL	Total WPL Common Equity
		Additional
	Common	Paid-In	Retained	Noncontrolling	Total
	Stock	Capital	Earnings	Interest	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$66	$2,413	$1,234	$—	$3,713
Net income			72		72
Common stock dividends			(46)		(46)
Ending balance, June 30, 2023	$66	$2,413	$1,260	$—	$3,739
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$66	$1,884	$1,101	$—	$3,051
Net income			63		63
Common stock dividends			(44)		(44)
Capital contributions from parent		85			85
Contributions from noncontrolling interest				29	29
Other		(1)			(1)
Ending balance, June 30, 2022	$66	$1,968	$1,120	$29	$3,183

WPL	Total WPL Common Equity
		Additional
	Common	Paid-In	Retained	Noncontrolling	Total
	Stock	Capital	Earnings	Interest	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$66	$2,233	$1,192	$—	$3,491
Net income			160		160
Common stock dividends			(92)		(92)
Capital contributions from parent		180			180
Ending balance, June 30, 2023	$66	$2,413	$1,260	$—	$3,739
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$66	$1,704	$1,053	$—	$2,823
Net income			156		156
Common stock dividends			(89)		(89)
Capital contributions from parent		265			265
Contributions from noncontrolling interest				29	29
Other		(1)			(1)
Ending balance, June 30, 2022	$66	$1,968	$1,120	$29	$3,183

WPL [Member]

Schedule of Capitalization, Equity [Line Items]

Changes in Shareowners' Equity

A summary of changes in shareowners’ equity was as follows (in millions):

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in
		Additional		Other	Deferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Noncontrolling	Total
	Stock	Capital	Earnings	Income (Loss)	Trust	Interest	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$3	$2,780	$3,559	($1)	($13)	$—	$6,328
Net income attributable to Alliant Energy common shareowners			160				160
Common stock dividends ($0.4525 per share)			(113)				(113)
At-the-market offering program and Shareowner Direct Plan issuances		70					70
Equity-based compensation plans and other		4			(1)		3
Other comprehensive income, net of tax				4			4
Ending balance, June 30, 2023	$3	$2,854	$3,606	$3	($14)	$—	$6,452
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$3	$2,750	$3,336	$—	($12)	$—	$6,077
Net income attributable to Alliant Energy common shareowners			159				159
Common stock dividends ($0.4275 per share)			(108)				(108)
Shareowner Direct Plan issuances		6					6
Equity-based compensation plans and other		3					3
Contributions from noncontrolling interest						29	29
Ending balance, June 30, 2022	$3	$2,759	$3,387	$—	($12)	$29	$6,166

Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in
		Additional		Other	Deferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Noncontrolling	Total
	Stock	Capital	Earnings	Income (Loss)	Trust	Interest	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$3	$2,777	$3,509	$—	($13)	$—	$6,276
Net income attributable to Alliant Energy common shareowners			323				323
Common stock dividends ($0.905 per share)			(226)				(226)
At-the-market offering program and Shareowner Direct Plan issuances		76					76
Equity-based compensation plans and other		1			(1)		—
Other comprehensive income, net of tax				3			3
Ending balance, June 30, 2023	$3	$2,854	$3,606	$3	($14)	$—	$6,452
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$3	$2,749	$3,250	$—	($12)	$—	$5,990
Net income attributable to Alliant Energy common shareowners			351				351
Common stock dividends ($0.855 per share)			(215)				(215)
Shareowner Direct Plan issuances		13					13
Equity-based compensation plans and other		(3)	1				(2)
Contributions from noncontrolling interest						29	29
Ending balance, June 30, 2022	$3	$2,759	$3,387	$—	($12)	$29	$6,166

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$33	$2,807	$970	$3,810
Net income			89	89
Common stock dividends			(70)	(70)
Capital contributions from parent		40		40
Ending balance, June 30, 2023	$33	$2,847	$989	$3,869
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$33	$2,807	$935	$3,775
Net income			87	87
Common stock dividends			(80)	(80)
Ending balance, June 30, 2022	$33	$2,807	$942	$3,782

IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$33	$2,807	$968	$3,808
Net income			161	161
Common stock dividends			(140)	(140)
Capital contributions from parent		40		40
Ending balance, June 30, 2023	$33	$2,847	$989	$3,869
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$33	$2,807	$929	$3,769
Net income			173	173
Common stock dividends			(160)	(160)
Ending balance, June 30, 2022	$33	$2,807	$942	$3,782

WPL	Total WPL Common Equity
		Additional
	Common	Paid-In	Retained	Noncontrolling	Total
	Stock	Capital	Earnings	Interest	Equity
Three Months Ended June 30, 2023
Beginning balance, March 31, 2023	$66	$2,413	$1,234	$—	$3,713
Net income			72		72
Common stock dividends			(46)		(46)
Ending balance, June 30, 2023	$66	$2,413	$1,260	$—	$3,739
Three Months Ended June 30, 2022
Beginning balance, March 31, 2022	$66	$1,884	$1,101	$—	$3,051
Net income			63		63
Common stock dividends			(44)		(44)
Capital contributions from parent		85			85
Contributions from noncontrolling interest				29	29
Other		(1)			(1)
Ending balance, June 30, 2022	$66	$1,968	$1,120	$29	$3,183

WPL	Total WPL Common Equity
		Additional
	Common	Paid-In	Retained	Noncontrolling	Total
	Stock	Capital	Earnings	Interest	Equity
Six Months Ended June 30, 2023
Beginning balance, December 31, 2022	$66	$2,233	$1,192	$—	$3,491
Net income			160		160
Common stock dividends			(92)		(92)
Capital contributions from parent		180			180
Ending balance, June 30, 2023	$66	$2,413	$1,260	$—	$3,739
Six Months Ended June 30, 2022
Beginning balance, December 31, 2021	$66	$1,704	$1,053	$—	$2,823
Net income			156		156
Common stock dividends			(89)		(89)
Capital contributions from parent		265			265
Contributions from noncontrolling interest				29	29
Other		(1)			(1)
Ending balance, June 30, 2022	$66	$1,968	$1,120	$29	$3,183

XML

Debt (Tables)

6 Months Ended

Jun. 30, 2023

Short-term Debt [Line Items]

Other Short-Term Borrowings

Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions):

June 30, 2023	Alliant Energy	IPL	WPL
Amount outstanding	$391	$—	$44
Weighted average interest rates	5.3%	—%	5.2%
Available credit facility capacity (a)	$554	$195	$256

	Alliant Energy		IPL		WPL
Three Months Ended June 30	2023	2022	2023	2022	2023	2022
Maximum amount outstanding (based on daily outstanding balances)	$391	$441	$70	$—	$91	$222
Average amount outstanding (based on daily outstanding balances)	$88	$337	$6	$—	$18	$166
Weighted average interest rates	5.3%	1.0%	5.3%	—%	5.2%	0.9%
Six Months Ended June 30
Maximum amount outstanding (based on daily outstanding balances)	$793	$577	$70	$—	$349	$252
Average amount outstanding (based on daily outstanding balances)	$330	$390	$3	$—	$160	$185
Weighted average interest rates	4.8%	0.6%	5.3%	—%	4.8%	0.5%

(a)Alliant Energy’s and IPL’s available credit facility capacities reflect outstanding commercial paper classified as both short- and long-term debt at June 30, 2023.

IPL [Member]

Short-term Debt [Line Items]

Other Short-Term Borrowings

Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions):

June 30, 2023	Alliant Energy	IPL	WPL
Amount outstanding	$391	$—	$44
Weighted average interest rates	5.3%	—%	5.2%
Available credit facility capacity (a)	$554	$195	$256

	Alliant Energy		IPL		WPL
Three Months Ended June 30	2023	2022	2023	2022	2023	2022
Maximum amount outstanding (based on daily outstanding balances)	$391	$441	$70	$—	$91	$222
Average amount outstanding (based on daily outstanding balances)	$88	$337	$6	$—	$18	$166
Weighted average interest rates	5.3%	1.0%	5.3%	—%	5.2%	0.9%
Six Months Ended June 30
Maximum amount outstanding (based on daily outstanding balances)	$793	$577	$70	$—	$349	$252
Average amount outstanding (based on daily outstanding balances)	$330	$390	$3	$—	$160	$185
Weighted average interest rates	4.8%	0.6%	5.3%	—%	4.8%	0.5%

(a)Alliant Energy’s and IPL’s available credit facility capacities reflect outstanding commercial paper classified as both short- and long-term debt at June 30, 2023.

WPL [Member]

Short-term Debt [Line Items]

Other Short-Term Borrowings

Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions):

June 30, 2023	Alliant Energy	IPL	WPL
Amount outstanding	$391	$—	$44
Weighted average interest rates	5.3%	—%	5.2%
Available credit facility capacity (a)	$554	$195	$256

	Alliant Energy		IPL		WPL
Three Months Ended June 30	2023	2022	2023	2022	2023	2022
Maximum amount outstanding (based on daily outstanding balances)	$391	$441	$70	$—	$91	$222
Average amount outstanding (based on daily outstanding balances)	$88	$337	$6	$—	$18	$166
Weighted average interest rates	5.3%	1.0%	5.3%	—%	5.2%	0.9%
Six Months Ended June 30
Maximum amount outstanding (based on daily outstanding balances)	$793	$577	$70	$—	$349	$252
Average amount outstanding (based on daily outstanding balances)	$330	$390	$3	$—	$160	$185
Weighted average interest rates	4.8%	0.6%	5.3%	—%	4.8%	0.5%

(a)Alliant Energy’s and IPL’s available credit facility capacities reflect outstanding commercial paper classified as both short- and long-term debt at June 30, 2023.

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Revenues (Tables)

6 Months Ended

Jun. 30, 2023

Disaggregation of Revenue [Line Items]

Disaggregation of Revenue

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

	Alliant Energy		IPL		WPL
Three Months Ended June 30	2023	2022	2023	2022	2023	2022
Electric Utility:
Retail - residential	$284	$289	$151	$158	$133	$131
Retail - commercial	201	196	129	127	72	69
Retail - industrial	245	244	130	136	115	108
Wholesale	49	54	14	16	35	38
Bulk power and other	20	29	7	5	13	24
Total Electric Utility	799	812	431	442	368	370
Gas Utility:
Retail - residential	42	51	24	28	18	23
Retail - commercial	22	27	12	14	10	13
Retail - industrial	3	3	2	2	1	1
Transportation/other	10	13	6	8	4	5
Total Gas Utility	77	94	44	52	33	42
Other Utility:
Steam	11	11	11	11	—	—
Other utility	2	2	1	1	1	1
Total Other Utility	13	13	12	12	1	1
Non-Utility and Other:
Travero and other	23	24	—	—	—	—
Total Non-Utility and Other	23	24	—	—	—	—
Total revenues	$912	$943	$487	$506	$402	$413

	Alliant Energy		IPL		WPL
Six Months Ended June 30	2023	2022	2023	2022	2023	2022
Electric Utility:
Retail - residential	$569	$581	$294	$308	$275	$273
Retail - commercial	385	386	241	246	144	140
Retail - industrial	460	453	236	246	224	207
Wholesale	95	101	26	31	69	70
Bulk power and other	58	65	22	12	36	53
Total Electric Utility	1,567	1,586	819	843	748	743
Gas Utility:
Retail - residential	210	210	117	113	93	97
Retail - commercial	110	109	56	54	54	55
Retail - industrial	9	11	6	7	3	4
Transportation/other	24	26	15	17	9	9
Total Gas Utility	353	356	194	191	159	165
Other Utility:
Steam	22	20	22	20	—	—
Other utility	3	3	2	2	1	1
Total Other Utility	25	23	24	22	1	1
Non-Utility and Other:
Travero and other	45	47	—	—	—	—
Total Non-Utility and Other	45	47	—	—	—	—
Total revenues	$1,990	$2,012	$1,037	$1,056	$908	$909

IPL [Member]

Disaggregation of Revenue [Line Items]

Disaggregation of Revenue

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

	Alliant Energy		IPL		WPL
Three Months Ended June 30	2023	2022	2023	2022	2023	2022
Electric Utility:
Retail - residential	$284	$289	$151	$158	$133	$131
Retail - commercial	201	196	129	127	72	69
Retail - industrial	245	244	130	136	115	108
Wholesale	49	54	14	16	35	38
Bulk power and other	20	29	7	5	13	24
Total Electric Utility	799	812	431	442	368	370
Gas Utility:
Retail - residential	42	51	24	28	18	23
Retail - commercial	22	27	12	14	10	13
Retail - industrial	3	3	2	2	1	1
Transportation/other	10	13	6	8	4	5
Total Gas Utility	77	94	44	52	33	42
Other Utility:
Steam	11	11	11	11	—	—
Other utility	2	2	1	1	1	1
Total Other Utility	13	13	12	12	1	1
Non-Utility and Other:
Travero and other	23	24	—	—	—	—
Total Non-Utility and Other	23	24	—	—	—	—
Total revenues	$912	$943	$487	$506	$402	$413

	Alliant Energy		IPL		WPL
Six Months Ended June 30	2023	2022	2023	2022	2023	2022
Electric Utility:
Retail - residential	$569	$581	$294	$308	$275	$273
Retail - commercial	385	386	241	246	144	140
Retail - industrial	460	453	236	246	224	207
Wholesale	95	101	26	31	69	70
Bulk power and other	58	65	22	12	36	53
Total Electric Utility	1,567	1,586	819	843	748	743
Gas Utility:
Retail - residential	210	210	117	113	93	97
Retail - commercial	110	109	56	54	54	55
Retail - industrial	9	11	6	7	3	4
Transportation/other	24	26	15	17	9	9
Total Gas Utility	353	356	194	191	159	165
Other Utility:
Steam	22	20	22	20	—	—
Other utility	3	3	2	2	1	1
Total Other Utility	25	23	24	22	1	1
Non-Utility and Other:
Travero and other	45	47	—	—	—	—
Total Non-Utility and Other	45	47	—	—	—	—
Total revenues	$1,990	$2,012	$1,037	$1,056	$908	$909

WPL [Member]

Disaggregation of Revenue [Line Items]

Disaggregation of Revenue

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

	Alliant Energy		IPL		WPL
Three Months Ended June 30	2023	2022	2023	2022	2023	2022
Electric Utility:
Retail - residential	$284	$289	$151	$158	$133	$131
Retail - commercial	201	196	129	127	72	69
Retail - industrial	245	244	130	136	115	108
Wholesale	49	54	14	16	35	38
Bulk power and other	20	29	7	5	13	24
Total Electric Utility	799	812	431	442	368	370
Gas Utility:
Retail - residential	42	51	24	28	18	23
Retail - commercial	22	27	12	14	10	13
Retail - industrial	3	3	2	2	1	1
Transportation/other	10	13	6	8	4	5
Total Gas Utility	77	94	44	52	33	42
Other Utility:
Steam	11	11	11	11	—	—
Other utility	2	2	1	1	1	1
Total Other Utility	13	13	12	12	1	1
Non-Utility and Other:
Travero and other	23	24	—	—	—	—
Total Non-Utility and Other	23	24	—	—	—	—
Total revenues	$912	$943	$487	$506	$402	$413

	Alliant Energy		IPL		WPL
Six Months Ended June 30	2023	2022	2023	2022	2023	2022
Electric Utility:
Retail - residential	$569	$581	$294	$308	$275	$273
Retail - commercial	385	386	241	246	144	140
Retail - industrial	460	453	236	246	224	207
Wholesale	95	101	26	31	69	70
Bulk power and other	58	65	22	12	36	53
Total Electric Utility	1,567	1,586	819	843	748	743
Gas Utility:
Retail - residential	210	210	117	113	93	97
Retail - commercial	110	109	56	54	54	55
Retail - industrial	9	11	6	7	3	4
Transportation/other	24	26	15	17	9	9
Total Gas Utility	353	356	194	191	159	165
Other Utility:
Steam	22	20	22	20	—	—
Other utility	3	3	2	2	1	1
Total Other Utility	25	23	24	22	1	1
Non-Utility and Other:
Travero and other	45	47	—	—	—	—
Total Non-Utility and Other	45	47	—	—	—	—
Total revenues	$1,990	$2,012	$1,037	$1,056	$908	$909

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Income Taxes (Tables)

6 Months Ended

Jun. 30, 2023

Income Taxes [Line Items]

Schedule Of Effective Income Tax Rates

Overall effective income tax rates, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences.

	Alliant Energy				IPL				WPL
	Three Months		Six Months		Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022
Overall income tax rate	—%	2%	(1%)	3%	(17%)	(16%)	(18%)	(15%)	16%	18%	14%	18%

Summary Of Tax Credit Carryforwards

At June 30, 2023, the carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy	IPL	WPL
State net operating losses	2025-2043	$503	$8	$1
Federal tax credits	2030-2043	708	485	214

IPL [Member]

Income Taxes [Line Items]

Schedule Of Effective Income Tax Rates

Overall effective income tax rates, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences.

	Alliant Energy				IPL				WPL
	Three Months		Six Months		Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022
Overall income tax rate	—%	2%	(1%)	3%	(17%)	(16%)	(18%)	(15%)	16%	18%	14%	18%

Summary Of Tax Credit Carryforwards

At June 30, 2023, the carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy	IPL	WPL
State net operating losses	2025-2043	$503	$8	$1
Federal tax credits	2030-2043	708	485	214

WPL [Member]

Income Taxes [Line Items]

Schedule Of Effective Income Tax Rates

Overall effective income tax rates, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences.

	Alliant Energy				IPL				WPL
	Three Months		Six Months		Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022
Overall income tax rate	—%	2%	(1%)	3%	(17%)	(16%)	(18%)	(15%)	16%	18%	14%	18%

Summary Of Tax Credit Carryforwards

At June 30, 2023, the carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy	IPL	WPL
State net operating losses	2025-2043	$503	$8	$1
Federal tax credits	2030-2043	708	485	214

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Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2023

Defined Benefit Plan Disclosure [Line Items]

Net Periodic Benefit Costs

The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are 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.

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
Alliant Energy	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$2	$2	$4	$—	$1	$1	$2
Interest cost	12	9	23	18	2	2	4	3
Expected return on plan assets	(13)	(17)	(26)	(34)	(1)	(2)	(2)	(3)
Amortization of actuarial loss	7	8	14	16	1	—	1	1
	$7	$2	$13	$4	$2	$1	$4	$3

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
IPL	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$1	$2	$3	$—	$1	$—	$1
Interest cost	5	4	10	8	1	—	2	1
Expected return on plan assets	(6)	(8)	(13)	(16)	(1)	(1)	(2)	(2)
Amortization of actuarial loss	3	4	6	7	1	—	1	—
	$3	$1	$5	$2	$1	$—	$1	$—

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
WPL	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$1	$1	$2	$—	$—	$—	$—
Interest cost	5	4	10	8	1	—	2	1
Expected return on plan assets	(6)	(8)	(11)	(16)	—	—	—	—
Amortization of actuarial loss	4	4	7	8	—	1	—	1
	$4	$1	$7	$2	$1	$1	$2	$2

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 for the three and six months ended June 30 was as follows (in millions):

	Alliant Energy				IPL				WPL
	Three Months		Six Months		Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022
Compensation expense	$3	$3	$6	$7	$2	$1	$3	$4	$1	$1	$2	$3
Income tax benefits	1	1	2	2	—	—	1	1	—	—	1	1

Schedule Of Equity-based Compensation Plans Activity

For the six months ended June 30, 2023, performance shares, performance restricted stock units and restricted stock units were granted to key employees under existing plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards.

		Weighted Average
	Grants	Grant Date Fair Value
Performance shares	106,927	$55.68
Performance restricted stock units	122,178	52.77
Restricted stock units	104,849	52.81

IPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Net Periodic Benefit Costs

The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are 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.

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
Alliant Energy	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$2	$2	$4	$—	$1	$1	$2
Interest cost	12	9	23	18	2	2	4	3
Expected return on plan assets	(13)	(17)	(26)	(34)	(1)	(2)	(2)	(3)
Amortization of actuarial loss	7	8	14	16	1	—	1	1
	$7	$2	$13	$4	$2	$1	$4	$3

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
IPL	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$1	$2	$3	$—	$1	$—	$1
Interest cost	5	4	10	8	1	—	2	1
Expected return on plan assets	(6)	(8)	(13)	(16)	(1)	(1)	(2)	(2)
Amortization of actuarial loss	3	4	6	7	1	—	1	—
	$3	$1	$5	$2	$1	$—	$1	$—

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
WPL	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$1	$1	$2	$—	$—	$—	$—
Interest cost	5	4	10	8	1	—	2	1
Expected return on plan assets	(6)	(8)	(11)	(16)	—	—	—	—
Amortization of actuarial loss	4	4	7	8	—	1	—	1
	$4	$1	$7	$2	$1	$1	$2	$2

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 for the three and six months ended June 30 was as follows (in millions):

	Alliant Energy				IPL				WPL
	Three Months		Six Months		Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022
Compensation expense	$3	$3	$6	$7	$2	$1	$3	$4	$1	$1	$2	$3
Income tax benefits	1	1	2	2	—	—	1	1	—	—	1	1

Schedule Of Equity-based Compensation Plans Activity

For the six months ended June 30, 2023, performance shares, performance restricted stock units and restricted stock units were granted to key employees under existing plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards.

		Weighted Average
	Grants	Grant Date Fair Value
Performance shares	106,927	$55.68
Performance restricted stock units	122,178	52.77
Restricted stock units	104,849	52.81

WPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Net Periodic Benefit Costs

The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are 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.

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
Alliant Energy	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$2	$2	$4	$—	$1	$1	$2
Interest cost	12	9	23	18	2	2	4	3
Expected return on plan assets	(13)	(17)	(26)	(34)	(1)	(2)	(2)	(3)
Amortization of actuarial loss	7	8	14	16	1	—	1	1
	$7	$2	$13	$4	$2	$1	$4	$3

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
IPL	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$1	$2	$3	$—	$1	$—	$1
Interest cost	5	4	10	8	1	—	2	1
Expected return on plan assets	(6)	(8)	(13)	(16)	(1)	(1)	(2)	(2)
Amortization of actuarial loss	3	4	6	7	1	—	1	—
	$3	$1	$5	$2	$1	$—	$1	$—

	Defined Benefit Pension Plans				OPEB Plans
	Three Months		Six Months		Three Months		Six Months
WPL	2023	2022	2023	2022	2023	2022	2023	2022
Service cost	$1	$1	$1	$2	$—	$—	$—	$—
Interest cost	5	4	10	8	1	—	2	1
Expected return on plan assets	(6)	(8)	(11)	(16)	—	—	—	—
Amortization of actuarial loss	4	4	7	8	—	1	—	1
	$4	$1	$7	$2	$1	$1	$2	$2

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 for the three and six months ended June 30 was as follows (in millions):

	Alliant Energy				IPL				WPL
	Three Months		Six Months		Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022
Compensation expense	$3	$3	$6	$7	$2	$1	$3	$4	$1	$1	$2	$3
Income tax benefits	1	1	2	2	—	—	1	1	—	—	1	1

Schedule Of Equity-based Compensation Plans Activity

For the six months ended June 30, 2023, performance shares, performance restricted stock units and restricted stock units were granted to key employees under existing plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards.

		Weighted Average
	Grants	Grant Date Fair Value
Performance shares	106,927	$55.68
Performance restricted stock units	122,178	52.77
Restricted stock units	104,849	52.81

XML

Derivative Instruments (Tables)

6 Months Ended

Jun. 30, 2023

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

As of June 30, 2023, 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):

	Electricity		FTRs		Natural Gas		Coal
	MWhs	Years	MWhs	Years	Dths	Years	Tons	Years
Alliant Energy	1,171	2023-2025	24,874	2023-2024	192,421	2023-2032	466	2023
IPL	537	2023-2025	10,163	2023-2024	92,087	2023-2030	224	2023
WPL	634	2023-2025	14,711	2023-2024	100,334	2023-2032	242	2023

Fair Value Of Financial Instruments

Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Current derivative assets	$86	$111	$61	$69	$25	$42
Non-current derivative assets	61	126	34	69	27	57
Current derivative liabilities	54	59	27	40	27	19
Non-current derivative liabilities	43	20	10	6	33	14

Balance Sheet Offsetting

However, if the fair value amounts of derivative instruments by counterparty were netted, derivative assets and derivative liabilities related to commodity contracts would have been presented on the balance sheets as follows (in millions):

	Alliant Energy		IPL		WPL
	Gross		Gross		Gross
	(as reported)	Net	(as reported)	Net	(as reported)	Net
June 30, 2023
Derivative assets	$147	$114	$95	$73	$52	$41
Derivative liabilities	97	64	37	15	60	49
December 31, 2022
Derivative assets	237	193	138	108	99	85
Derivative liabilities	79	35	46	16	33	19

IPL [Member]

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

As of June 30, 2023, 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):

	Electricity		FTRs		Natural Gas		Coal
	MWhs	Years	MWhs	Years	Dths	Years	Tons	Years
Alliant Energy	1,171	2023-2025	24,874	2023-2024	192,421	2023-2032	466	2023
IPL	537	2023-2025	10,163	2023-2024	92,087	2023-2030	224	2023
WPL	634	2023-2025	14,711	2023-2024	100,334	2023-2032	242	2023

Fair Value Of Financial Instruments

Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Current derivative assets	$86	$111	$61	$69	$25	$42
Non-current derivative assets	61	126	34	69	27	57
Current derivative liabilities	54	59	27	40	27	19
Non-current derivative liabilities	43	20	10	6	33	14

Balance Sheet Offsetting

However, if the fair value amounts of derivative instruments by counterparty were netted, derivative assets and derivative liabilities related to commodity contracts would have been presented on the balance sheets as follows (in millions):

	Alliant Energy		IPL		WPL
	Gross		Gross		Gross
	(as reported)	Net	(as reported)	Net	(as reported)	Net
June 30, 2023
Derivative assets	$147	$114	$95	$73	$52	$41
Derivative liabilities	97	64	37	15	60	49
December 31, 2022
Derivative assets	237	193	138	108	99	85
Derivative liabilities	79	35	46	16	33	19

WPL [Member]

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

As of June 30, 2023, 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):

	Electricity		FTRs		Natural Gas		Coal
	MWhs	Years	MWhs	Years	Dths	Years	Tons	Years
Alliant Energy	1,171	2023-2025	24,874	2023-2024	192,421	2023-2032	466	2023
IPL	537	2023-2025	10,163	2023-2024	92,087	2023-2030	224	2023
WPL	634	2023-2025	14,711	2023-2024	100,334	2023-2032	242	2023

Fair Value Of Financial Instruments

Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions):

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Current derivative assets	$86	$111	$61	$69	$25	$42
Non-current derivative assets	61	126	34	69	27	57
Current derivative liabilities	54	59	27	40	27	19
Non-current derivative liabilities	43	20	10	6	33	14

Balance Sheet Offsetting

However, if the fair value amounts of derivative instruments by counterparty were netted, derivative assets and derivative liabilities related to commodity contracts would have been presented on the balance sheets as follows (in millions):

	Alliant Energy		IPL		WPL
	Gross		Gross		Gross
	(as reported)	Net	(as reported)	Net	(as reported)	Net
June 30, 2023
Derivative assets	$147	$114	$95	$73	$52	$41
Derivative liabilities	97	64	37	15	60	49
December 31, 2022
Derivative assets	237	193	138	108	99	85
Derivative liabilities	79	35	46	16	33	19

XML

Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2023

Statement [Line Items]

Fair Value Measurements

Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions):

Alliant Energy	June 30, 2023					December 31, 2022
		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	$6	$6	$—	$—	$6	$10	$10	$—	$—	$10
Commodity derivatives	147	—	80	67	147	237	—	206	31	237
Interest rate derivatives	4	—	4	—	4	—	—	—	—	—
Deferred proceeds	175	—	—	175	175	185	—	—	185	185
Liabilities:
Commodity derivatives	97	—	84	13	97	79	—	67	12	79
Long-term debt (incl. current maturities)	8,595	—	7,950	1	7,951	8,076	—	7,338	1	7,339

IPL	June 30, 2023					December 31, 2022
		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	$6	$6	$—	$—	$6	$10	$10	$—	$—	$10
Commodity derivatives	95	—	44	51	95	138	—	111	27	138
Deferred proceeds	175	—	—	175	175	185	—	—	185	185
Liabilities:
Commodity derivatives	37	—	27	10	37	46	—	35	11	46
Long-term debt	3,702	—	3,321	—	3,321	3,646	—	3,228	—	3,228

WPL	June 30, 2023					December 31, 2022
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Commodity derivatives	$52	$—	$36	$16	$52	$99	$—	$95	$4	$99
Liabilities:
Commodity derivatives	60	—	57	3	60	33	—	32	1	33
Long-term debt	3,068	—	2,875	—	2,875	2,770	—	2,542	—	2,542

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
Three Months Ended June 30	2023	2022	2023	2022
Beginning balance, April 1	($5)	$10	$153	$227
Total net losses included in changes in net assets (realized/unrealized)	(7)	(10)	—	—
Purchases	62	79	—	—
Sales	(1)	—	—	—
Settlements (a)	5	(7)	22	17
Ending balance, June 30	$54	$72	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($7)	($10)	$—	$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Six Months Ended June 30	2023	2022	2023	2022
Beginning balance, January 1	$19	$29	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(11)	(16)	—	—
Purchases	62	79	—	—
Sales	(1)	—	—	—
Settlements (a)	(15)	(20)	(10)	30
Ending balance, June 30	$54	$72	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($11)	($16)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Three Months Ended June 30	2023	2022	2023	2022
Beginning balance, April 1	$—	$7	$153	$227
Total net losses included in changes in net assets (realized/unrealized)	(13)	(3)	—	—
Purchases	51	58	—	—
Sales	(1)	—	—	—
Settlements (a)	4	(4)	22	17
Ending balance, June 30	$41	$58	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($13)	($3)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Six Months Ended June 30	2023	2022	2023	2022
Beginning balance, January 1	$16	$18	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(12)	(7)	—	—
Purchases	51	58	—	—
Sales	(1)	—	—	—
Settlements (a)	(13)	(11)	(10)	30
Ending balance, June 30	$41	$58	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($12)	($8)	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Three Months Ended June 30	2023	2022
Beginning balance, April 1	($5)	$3
Total net gains (losses) included in changes in net assets (realized/unrealized)	6	(7)
Purchases	11	21
Settlements	1	(3)
Ending balance, June 30	$13	$14
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 June 30	$6	($7)

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Six Months Ended June 30	2023	2022
Beginning balance, January 1	$3	$11
Total net gains (losses) included in changes in net assets (realized/unrealized)	1	(9)
Purchases	11	21
Settlements	(2)	(9)
Ending balance, June 30	$13	$14
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 June 30	$1	($8)

(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 (liabilities) as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
June 30, 2023	($8)	$62	($5)	$46	($3)	$16
December 31, 2022	(10)	29	(9)	25	(1)	4

IPL [Member]

Statement [Line Items]

Fair Value Measurements

Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions):

Alliant Energy	June 30, 2023					December 31, 2022
		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	$6	$6	$—	$—	$6	$10	$10	$—	$—	$10
Commodity derivatives	147	—	80	67	147	237	—	206	31	237
Interest rate derivatives	4	—	4	—	4	—	—	—	—	—
Deferred proceeds	175	—	—	175	175	185	—	—	185	185
Liabilities:
Commodity derivatives	97	—	84	13	97	79	—	67	12	79
Long-term debt (incl. current maturities)	8,595	—	7,950	1	7,951	8,076	—	7,338	1	7,339

IPL	June 30, 2023					December 31, 2022
		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	$6	$6	$—	$—	$6	$10	$10	$—	$—	$10
Commodity derivatives	95	—	44	51	95	138	—	111	27	138
Deferred proceeds	175	—	—	175	175	185	—	—	185	185
Liabilities:
Commodity derivatives	37	—	27	10	37	46	—	35	11	46
Long-term debt	3,702	—	3,321	—	3,321	3,646	—	3,228	—	3,228

WPL	June 30, 2023					December 31, 2022
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Commodity derivatives	$52	$—	$36	$16	$52	$99	$—	$95	$4	$99
Liabilities:
Commodity derivatives	60	—	57	3	60	33	—	32	1	33
Long-term debt	3,068	—	2,875	—	2,875	2,770	—	2,542	—	2,542

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
Three Months Ended June 30	2023	2022	2023	2022
Beginning balance, April 1	($5)	$10	$153	$227
Total net losses included in changes in net assets (realized/unrealized)	(7)	(10)	—	—
Purchases	62	79	—	—
Sales	(1)	—	—	—
Settlements (a)	5	(7)	22	17
Ending balance, June 30	$54	$72	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($7)	($10)	$—	$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Six Months Ended June 30	2023	2022	2023	2022
Beginning balance, January 1	$19	$29	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(11)	(16)	—	—
Purchases	62	79	—	—
Sales	(1)	—	—	—
Settlements (a)	(15)	(20)	(10)	30
Ending balance, June 30	$54	$72	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($11)	($16)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Three Months Ended June 30	2023	2022	2023	2022
Beginning balance, April 1	$—	$7	$153	$227
Total net losses included in changes in net assets (realized/unrealized)	(13)	(3)	—	—
Purchases	51	58	—	—
Sales	(1)	—	—	—
Settlements (a)	4	(4)	22	17
Ending balance, June 30	$41	$58	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($13)	($3)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Six Months Ended June 30	2023	2022	2023	2022
Beginning balance, January 1	$16	$18	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(12)	(7)	—	—
Purchases	51	58	—	—
Sales	(1)	—	—	—
Settlements (a)	(13)	(11)	(10)	30
Ending balance, June 30	$41	$58	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($12)	($8)	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Three Months Ended June 30	2023	2022
Beginning balance, April 1	($5)	$3
Total net gains (losses) included in changes in net assets (realized/unrealized)	6	(7)
Purchases	11	21
Settlements	1	(3)
Ending balance, June 30	$13	$14
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 June 30	$6	($7)

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Six Months Ended June 30	2023	2022
Beginning balance, January 1	$3	$11
Total net gains (losses) included in changes in net assets (realized/unrealized)	1	(9)
Purchases	11	21
Settlements	(2)	(9)
Ending balance, June 30	$13	$14
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 June 30	$1	($8)

(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 (liabilities) as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
June 30, 2023	($8)	$62	($5)	$46	($3)	$16
December 31, 2022	(10)	29	(9)	25	(1)	4

WPL [Member]

Statement [Line Items]

Fair Value Measurements

Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions):

Alliant Energy	June 30, 2023					December 31, 2022
		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	$6	$6	$—	$—	$6	$10	$10	$—	$—	$10
Commodity derivatives	147	—	80	67	147	237	—	206	31	237
Interest rate derivatives	4	—	4	—	4	—	—	—	—	—
Deferred proceeds	175	—	—	175	175	185	—	—	185	185
Liabilities:
Commodity derivatives	97	—	84	13	97	79	—	67	12	79
Long-term debt (incl. current maturities)	8,595	—	7,950	1	7,951	8,076	—	7,338	1	7,339

IPL	June 30, 2023					December 31, 2022
		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	$6	$6	$—	$—	$6	$10	$10	$—	$—	$10
Commodity derivatives	95	—	44	51	95	138	—	111	27	138
Deferred proceeds	175	—	—	175	175	185	—	—	185	185
Liabilities:
Commodity derivatives	37	—	27	10	37	46	—	35	11	46
Long-term debt	3,702	—	3,321	—	3,321	3,646	—	3,228	—	3,228

WPL	June 30, 2023					December 31, 2022
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Commodity derivatives	$52	$—	$36	$16	$52	$99	$—	$95	$4	$99
Liabilities:
Commodity derivatives	60	—	57	3	60	33	—	32	1	33
Long-term debt	3,068	—	2,875	—	2,875	2,770	—	2,542	—	2,542

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
Three Months Ended June 30	2023	2022	2023	2022
Beginning balance, April 1	($5)	$10	$153	$227
Total net losses included in changes in net assets (realized/unrealized)	(7)	(10)	—	—
Purchases	62	79	—	—
Sales	(1)	—	—	—
Settlements (a)	5	(7)	22	17
Ending balance, June 30	$54	$72	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($7)	($10)	$—	$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Six Months Ended June 30	2023	2022	2023	2022
Beginning balance, January 1	$19	$29	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(11)	(16)	—	—
Purchases	62	79	—	—
Sales	(1)	—	—	—
Settlements (a)	(15)	(20)	(10)	30
Ending balance, June 30	$54	$72	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($11)	($16)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Three Months Ended June 30	2023	2022	2023	2022
Beginning balance, April 1	$—	$7	$153	$227
Total net losses included in changes in net assets (realized/unrealized)	(13)	(3)	—	—
Purchases	51	58	—	—
Sales	(1)	—	—	—
Settlements (a)	4	(4)	22	17
Ending balance, June 30	$41	$58	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($13)	($3)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Six Months Ended June 30	2023	2022	2023	2022
Beginning balance, January 1	$16	$18	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(12)	(7)	—	—
Purchases	51	58	—	—
Sales	(1)	—	—	—
Settlements (a)	(13)	(11)	(10)	30
Ending balance, June 30	$41	$58	$175	$244
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30	($12)	($8)	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Three Months Ended June 30	2023	2022
Beginning balance, April 1	($5)	$3
Total net gains (losses) included in changes in net assets (realized/unrealized)	6	(7)
Purchases	11	21
Settlements	1	(3)
Ending balance, June 30	$13	$14
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 June 30	$6	($7)

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Six Months Ended June 30	2023	2022
Beginning balance, January 1	$3	$11
Total net gains (losses) included in changes in net assets (realized/unrealized)	1	(9)
Purchases	11	21
Settlements	(2)	(9)
Ending balance, June 30	$13	$14
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 June 30	$1	($8)

(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 (liabilities) as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
June 30, 2023	($8)	$62	($5)	$46	($3)	$16
December 31, 2022	(10)	29	(9)	25	(1)	4

XML

Commitments And Contingencies (Tables)

6 Months Ended

Jun. 30, 2023

Commitments and Contingencies [Line Items]

Other Purchase Commitments

At June 30, 2023, related minimum future commitments were as follows (in millions):

	Alliant Energy	IPL	WPL
Natural gas	$1,083	$494	$589
Coal	163	79	84
Other (a)	106	51	25
	$1,352	$624	$698

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2023.

MGP Site Estimated Future Costs And Recorded Liabilities

At June 30, 2023, 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):

	Alliant Energy			IPL			WPL
Range of estimated future costs	$9	-	$36	$5	-	$11	$4	-	$25
Current and non-current environmental liabilities	$18			$8			$10

IPL [Member]

Commitments and Contingencies [Line Items]

Other Purchase Commitments

At June 30, 2023, related minimum future commitments were as follows (in millions):

	Alliant Energy	IPL	WPL
Natural gas	$1,083	$494	$589
Coal	163	79	84
Other (a)	106	51	25
	$1,352	$624	$698

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2023.

MGP Site Estimated Future Costs And Recorded Liabilities

At June 30, 2023, 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):

	Alliant Energy			IPL			WPL
Range of estimated future costs	$9	-	$36	$5	-	$11	$4	-	$25
Current and non-current environmental liabilities	$18			$8			$10

WPL [Member]

Commitments and Contingencies [Line Items]

Other Purchase Commitments

At June 30, 2023, related minimum future commitments were as follows (in millions):

	Alliant Energy	IPL	WPL
Natural gas	$1,083	$494	$589
Coal	163	79	84
Other (a)	106	51	25
	$1,352	$624	$698

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2023.

MGP Site Estimated Future Costs And Recorded Liabilities

At June 30, 2023, 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):

	Alliant Energy			IPL			WPL
Range of estimated future costs	$9	-	$36	$5	-	$11	$4	-	$25
Current and non-current environmental liabilities	$18			$8			$10

XML

Segments Of Business (Tables)

6 Months Ended

Jun. 30, 2023

Segment Reporting Information [Line Items]

Schedule Of Segments Of Business

Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s business segments is as follows. Intersegment revenues were not material to their respective operations.

Alliant Energy					ATC Holdings,	Alliant
	Utility				Non-Utility,	Energy
	Electric	Gas	Other	Total	Parent and Other	Consolidated
	(in millions)
Three Months Ended June 30, 2023
Revenues	$799	$77	$13	$889	$23	$912
Operating income	200	2	7	209	8	217
Net income (loss) attributable to Alliant Energy common shareowners				161	(1)	160
Three Months Ended June 30, 2022
Revenues	$812	$94	$13	$919	$24	$943
Operating income	195	8	1	204	8	212
Net income attributable to Alliant Energy common shareowners				150	9	159

Alliant Energy					ATC Holdings,	Alliant
	Utility				Non-Utility,	Energy
	Electric	Gas	Other	Total	Parent and Other	Consolidated
	(in millions)
Six Months Ended June 30, 2023
Revenues	$1,567	$353	$25	$1,945	$45	$1,990
Operating income	363	52	11	426	13	439
Net income attributable to Alliant Energy common shareowners				321	2	323
Six Months Ended June 30, 2022
Revenues	$1,586	$356	$23	$1,965	$47	$2,012
Operating income	376	65	4	445	15	460
Net income attributable to Alliant Energy common shareowners				329	22	351

IPL	Electric	Gas	Other	Total
	(in millions)
Three Months Ended June 30, 2023
Revenues	$431	$44	$12	$487
Operating income	105	—	5	110
Net income				89
Three Months Ended June 30, 2022
Revenues	$442	$52	$12	$506
Operating income	104	4	1	109
Net income				87
Six Months Ended June 30, 2023
Revenues	$819	$194	$24	$1,037
Operating income	171	27	8	206
Net income				161
Six Months Ended June 30, 2022
Revenues	$843	$191	$22	$1,056
Operating income	179	36	3	218
Net income				173

WPL	Electric	Gas	Other	Total
	(in millions)
Three Months Ended June 30, 2023
Revenues	$368	$33	$1	$402
Operating income	95	2	2	99
Net income				72
Three Months Ended June 30, 2022
Revenues	$370	$42	$1	$413
Operating income	91	4	—	95
Net income				63
Six Months Ended June 30, 2023
Revenues	$748	$159	$1	$908
Operating income	192	25	3	220
Net income				160
Six Months Ended June 30, 2022
Revenues	$743	$165	$1	$909
Operating income	197	29	1	227
Net income				156

IPL [Member]

Segment Reporting Information [Line Items]

Schedule Of Segments Of Business

Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s business segments is as follows. Intersegment revenues were not material to their respective operations.

Alliant Energy					ATC Holdings,	Alliant
	Utility				Non-Utility,	Energy
	Electric	Gas	Other	Total	Parent and Other	Consolidated
	(in millions)
Three Months Ended June 30, 2023
Revenues	$799	$77	$13	$889	$23	$912
Operating income	200	2	7	209	8	217
Net income (loss) attributable to Alliant Energy common shareowners				161	(1)	160
Three Months Ended June 30, 2022
Revenues	$812	$94	$13	$919	$24	$943
Operating income	195	8	1	204	8	212
Net income attributable to Alliant Energy common shareowners				150	9	159

Alliant Energy					ATC Holdings,	Alliant
	Utility				Non-Utility,	Energy
	Electric	Gas	Other	Total	Parent and Other	Consolidated
	(in millions)
Six Months Ended June 30, 2023
Revenues	$1,567	$353	$25	$1,945	$45	$1,990
Operating income	363	52	11	426	13	439
Net income attributable to Alliant Energy common shareowners				321	2	323
Six Months Ended June 30, 2022
Revenues	$1,586	$356	$23	$1,965	$47	$2,012
Operating income	376	65	4	445	15	460
Net income attributable to Alliant Energy common shareowners				329	22	351

IPL	Electric	Gas	Other	Total
	(in millions)
Three Months Ended June 30, 2023
Revenues	$431	$44	$12	$487
Operating income	105	—	5	110
Net income				89
Three Months Ended June 30, 2022
Revenues	$442	$52	$12	$506
Operating income	104	4	1	109
Net income				87
Six Months Ended June 30, 2023
Revenues	$819	$194	$24	$1,037
Operating income	171	27	8	206
Net income				161
Six Months Ended June 30, 2022
Revenues	$843	$191	$22	$1,056
Operating income	179	36	3	218
Net income				173

WPL	Electric	Gas	Other	Total
	(in millions)
Three Months Ended June 30, 2023
Revenues	$368	$33	$1	$402
Operating income	95	2	2	99
Net income				72
Three Months Ended June 30, 2022
Revenues	$370	$42	$1	$413
Operating income	91	4	—	95
Net income				63
Six Months Ended June 30, 2023
Revenues	$748	$159	$1	$908
Operating income	192	25	3	220
Net income				160
Six Months Ended June 30, 2022
Revenues	$743	$165	$1	$909
Operating income	197	29	1	227
Net income				156

WPL [Member]

Segment Reporting Information [Line Items]

Schedule Of Segments Of Business

Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s business segments is as follows. Intersegment revenues were not material to their respective operations.

Alliant Energy					ATC Holdings,	Alliant
	Utility				Non-Utility,	Energy
	Electric	Gas	Other	Total	Parent and Other	Consolidated
	(in millions)
Three Months Ended June 30, 2023
Revenues	$799	$77	$13	$889	$23	$912
Operating income	200	2	7	209	8	217
Net income (loss) attributable to Alliant Energy common shareowners				161	(1)	160
Three Months Ended June 30, 2022
Revenues	$812	$94	$13	$919	$24	$943
Operating income	195	8	1	204	8	212
Net income attributable to Alliant Energy common shareowners				150	9	159

Alliant Energy					ATC Holdings,	Alliant
	Utility				Non-Utility,	Energy
	Electric	Gas	Other	Total	Parent and Other	Consolidated
	(in millions)
Six Months Ended June 30, 2023
Revenues	$1,567	$353	$25	$1,945	$45	$1,990
Operating income	363	52	11	426	13	439
Net income attributable to Alliant Energy common shareowners				321	2	323
Six Months Ended June 30, 2022
Revenues	$1,586	$356	$23	$1,965	$47	$2,012
Operating income	376	65	4	445	15	460
Net income attributable to Alliant Energy common shareowners				329	22	351

IPL	Electric	Gas	Other	Total
	(in millions)
Three Months Ended June 30, 2023
Revenues	$431	$44	$12	$487
Operating income	105	—	5	110
Net income				89
Three Months Ended June 30, 2022
Revenues	$442	$52	$12	$506
Operating income	104	4	1	109
Net income				87
Six Months Ended June 30, 2023
Revenues	$819	$194	$24	$1,037
Operating income	171	27	8	206
Net income				161
Six Months Ended June 30, 2022
Revenues	$843	$191	$22	$1,056
Operating income	179	36	3	218
Net income				173

WPL	Electric	Gas	Other	Total
	(in millions)
Three Months Ended June 30, 2023
Revenues	$368	$33	$1	$402
Operating income	95	2	2	99
Net income				72
Three Months Ended June 30, 2022
Revenues	$370	$42	$1	$413
Operating income	91	4	—	95
Net income				63
Six Months Ended June 30, 2023
Revenues	$748	$159	$1	$908
Operating income	192	25	3	220
Net income				160
Six Months Ended June 30, 2022
Revenues	$743	$165	$1	$909
Operating income	197	29	1	227
Net income				156

XML

Related Parties (Tables)

6 Months Ended

Jun. 30, 2023

Related Party Transactions [Line Items]

Services Provided, Sales Credited And Purchases

The amounts billed for services provided, sales credited and purchases for the three and six months ended June 30 were as follows (in millions):

	IPL				WPL
	Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022
Corporate Services billings	$48	$51	$88	$91	$43	$42	$80	$78
Sales credited	1	—	8	—	10	13	22	31
Purchases billed	94	129	187	223	2	39	17	61

Net Intercompany Payables

Net intercompany payables to Corporate Services were as follows (in millions):

	IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Net payables to Corporate Services	$116	$103	$73	$56

Related Amounts Billed Between Parties

The related amounts billed between the parties for the three and six months ended June 30 were as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
ATC billings to WPL	$44	$35	$78	$69
WPL billings to ATC	5	5	11	8

IPL [Member]

Related Party Transactions [Line Items]

Services Provided, Sales Credited And Purchases

The amounts billed for services provided, sales credited and purchases for the three and six months ended June 30 were as follows (in millions):

	IPL				WPL
	Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022
Corporate Services billings	$48	$51	$88	$91	$43	$42	$80	$78
Sales credited	1	—	8	—	10	13	22	31
Purchases billed	94	129	187	223	2	39	17	61

Net Intercompany Payables

Net intercompany payables to Corporate Services were as follows (in millions):

	IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Net payables to Corporate Services	$116	$103	$73	$56

WPL [Member]

Related Party Transactions [Line Items]

Services Provided, Sales Credited And Purchases

The amounts billed for services provided, sales credited and purchases for the three and six months ended June 30 were as follows (in millions):

	IPL				WPL
	Three Months		Six Months		Three Months		Six Months
	2023	2022	2023	2022	2023	2022	2023	2022
Corporate Services billings	$48	$51	$88	$91	$43	$42	$80	$78
Sales credited	1	—	8	—	10	13	22	31
Purchases billed	94	129	187	223	2	39	17	61

Net Intercompany Payables

Net intercompany payables to Corporate Services were as follows (in millions):

	IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Net payables to Corporate Services	$116	$103	$73	$56

Related Amounts Billed Between Parties

The related amounts billed between the parties for the three and six months ended June 30 were as follows (in millions):

	Three Months		Six Months
	2023	2022	2023	2022
ATC billings to WPL	$44	$35	$78	$69
WPL billings to ATC	5	5	11	8

XML

Regulatory Matters (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Regulatory Matters [Line Items]
Regulatory assets	$ 2,344	$ 2,046
IPL [Member]
Regulatory Matters [Line Items]
Regulatory assets	1,648	1,386
WPL [Member]
Regulatory Matters [Line Items]
Regulatory assets	696	660
Assets retired early [Member]
Regulatory Matters [Line Items]
Regulatory assets	290	70
Assets retired early [Member] | IPL [Member]
Regulatory Matters [Line Items]
Regulatory assets	274	53
Assets retired early [Member] | WPL [Member]
Regulatory Matters [Line Items]
Regulatory assets	16	$ 17
Assets retired early [Member] | Lansing Generating Station
Regulatory Matters [Line Items]
Regulatory assets	226
Assets retired early [Member] | Lansing Generating Station | IPL [Member]
Regulatory Matters [Line Items]
Regulatory assets	$ 226

XML

Regulatory Matters (Regulatory Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Regulatory Assets [Line Items]
Regulatory assets	$ 2,344	$ 2,046
Tax-related [Member]
Regulatory Assets [Line Items]
Regulatory assets	957	929
Pension and OPEB costs [Member]
Regulatory Assets [Line Items]
Regulatory assets	378	392
Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	290	70
Asset retirement obligations [Member]
Regulatory Assets [Line Items]
Regulatory assets	197	151
Commodity cost recovery [Member]
Regulatory Assets [Line Items]
Regulatory assets	145	160
Derivatives [Member]
Regulatory Assets [Line Items]
Regulatory assets	102	84
IPL's Duane Arnold Energy Center PPA amendment [Member]
Regulatory Assets [Line Items]
Regulatory assets	54	66
WPL's Western Wisconsin gas distribution expansion investments [Member]
Regulatory Assets [Line Items]
Regulatory assets	47	48
Other [Member]
Regulatory Assets [Line Items]
Regulatory assets	174	146
IPL [Member]
Regulatory Assets [Line Items]
Regulatory assets	1,648	1,386
IPL [Member] | Tax-related [Member]
Regulatory Assets [Line Items]
Regulatory assets	868	848
IPL [Member] | Pension and OPEB costs [Member]
Regulatory Assets [Line Items]
Regulatory assets	190	197
IPL [Member] | Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	274	53
IPL [Member] | Asset retirement obligations [Member]
Regulatory Assets [Line Items]
Regulatory assets	156	110
IPL [Member] | Commodity cost recovery [Member]
Regulatory Assets [Line Items]
Regulatory assets	6	1
IPL [Member] | Derivatives [Member]
Regulatory Assets [Line Items]
Regulatory assets	41	48
IPL [Member] | IPL's Duane Arnold Energy Center PPA amendment [Member]
Regulatory Assets [Line Items]
Regulatory assets	54	66
IPL [Member] | Other [Member]
Regulatory Assets [Line Items]
Regulatory assets	59	63
WPL [Member]
Regulatory Assets [Line Items]
Regulatory assets	696	660
WPL [Member] | Tax-related [Member]
Regulatory Assets [Line Items]
Regulatory assets	89	81
WPL [Member] | Pension and OPEB costs [Member]
Regulatory Assets [Line Items]
Regulatory assets	188	195
WPL [Member] | Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	16	17
WPL [Member] | Asset retirement obligations [Member]
Regulatory Assets [Line Items]
Regulatory assets	41	41
WPL [Member] | Commodity cost recovery [Member]
Regulatory Assets [Line Items]
Regulatory assets	139	159
WPL [Member] | Derivatives [Member]
Regulatory Assets [Line Items]
Regulatory assets	61	36
WPL [Member] | WPL's Western Wisconsin gas distribution expansion investments [Member]
Regulatory Assets [Line Items]
Regulatory assets	47	48
WPL [Member] | Other [Member]
Regulatory Assets [Line Items]
Regulatory assets	$ 115	$ 83

XML

Regulatory Matters (Regulatory Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Regulatory Liabilities [Line Items]
Regulatory liabilities	$ 1,208	$ 1,324
Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	572	579
Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	405	398
Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	90	210
Commodity cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	39	40
Electric transmission cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	19	20
WPL's West Riverside liquidated damages [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	17	32
Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	66	45
IPL [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	676	754
IPL [Member] | Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	301	303
IPL [Member] | Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	260	259
IPL [Member] | Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	48	115
IPL [Member] | Commodity cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	15	38
IPL [Member] | Electric transmission cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	14	10
IPL [Member] | Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	38	29
WPL [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	532	570
WPL [Member] | Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	271	276
WPL [Member] | Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	145	139
WPL [Member] | Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	42	95
WPL [Member] | Commodity cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	24	2
WPL [Member] | Electric transmission cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	5	10
WPL [Member] | WPL's West Riverside liquidated damages [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	17	32
WPL [Member] | Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	$ 28	$ 16

XML

Property, Plant and Equipment (Narrative) (Details)	Jun. 30, 2023
WPL [Member] | West Riverside Energy Center [Member]
Property, Plant and Equipment [Line Items]
Ownership interest, percent	73.80%

XML

Receivables (Narrative) (Details) - Receivables Sold [Member] - IPL [Member] $ in Millions	Jun. 30, 2023 USD ($)
Receivables [Line Items]
Available capacity	$ 50
Financial Asset, Past Due [Member]
Receivables [Line Items]
Outstanding receivables past due	$ 20

XML

Receivables (Gross Write-offs For Accounts Receivable) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Gross write-offs for accounts receivable, originated in 2022	$ 3	$ 8
Gross write-offs for accounts receivable, originated in 2023	2	2
IPL [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Gross write-offs for accounts receivable, originated in 2022	2	5
Gross write-offs for accounts receivable, originated in 2023	1	1
WPL [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Gross write-offs for accounts receivable, originated in 2022	1	3
Gross write-offs for accounts receivable, originated in 2023	$ 1	$ 1

XML

Receivables (Maximum And Average Outstanding Cash Proceeds) (Details) - IPL [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Maximum [Member]
Receivables [Line Items]
Maximum outstanding aggregate cash proceeds (based on daily outstanding balances)	$ 110	$ 66	$ 110	$ 66
Average [Member]
Receivables [Line Items]
Average outstanding aggregate cash proceeds (based on daily outstanding balances)	$ 101	$ 18	$ 79	$ 11

XML

Receivables (Receivables Sold Under The Agreement) (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Receivables [Line Items]
Fair value of deferred proceeds	$ 175	$ 185
IPL [Member]
Receivables [Line Items]
Fair value of deferred proceeds	175	185
Receivables Sold [Member] | IPL [Member]
Receivables [Line Items]
Customer accounts receivable	148	145
Unbilled utility revenues	100	132
Receivables sold to third party	248	277
Less: cash proceeds	60	80
Deferred proceeds	188	197
Less: allowance for expected credit losses	13	12
Fair value of deferred proceeds	$ 175	$ 185

XML

Receivables (Additional Attributes Of Receivables Sold Under The Agreement) (Details) - IPL [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Receivables [Line Items]
Collections	$ 514	$ 500	$ 1,104	$ 1,061
Write-offs, net of recoveries	$ 2	$ 1	$ 4	$ 3

XML

Investments (Unconsolidated Equity Investments) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Schedule of Equity Method Investments [Line Items]
Equity (income) loss from unconsolidated investments, net	$ (14)	$ (16)	$ (31)	$ (32)
ATC Holdings [Member]
Schedule of Equity Method Investments [Line Items]
Equity (income) loss from unconsolidated investments, net	(12)	(11)	(25)	(23)
Other [Member]
Schedule of Equity Method Investments [Line Items]
Equity (income) loss from unconsolidated investments, net	(2)	(5)	(6)	(9)
Total [Member]
Schedule of Equity Method Investments [Line Items]
Equity (income) loss from unconsolidated investments, net	$ (14)	$ (16)	$ (31)	$ (32)

XML

Common Equity (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 31, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2023
Common Equity [Line Items]
Proceeds from issuance of common stock, net		$ 70	$ 6	$ 76	$ 13
Common stock issued during period, At-the-market offering program (in shares)				134,334
At The Market Offering Program
Common Equity [Line Items]
Proceeds from issuance of common stock, net				$ 64
Fees and commissions from issuance of common stock				$ 1
Common stock issued during period, At-the-market offering program (in shares)				1,221,775
At The Market Offering Program | Subsequent Event [Member]
Common Equity [Line Items]
Proceeds from issuance of common stock, net	$ 9
Common stock issued during period, At-the-market offering program (in shares)	172,701
At The Market Offering Program | Forecast [Member]
Common Equity [Line Items]
Maximum aggregate gross sales price of common stock that can be offered and sold						$ 225

XML

Common Equity (Common Share Activity) (Details) - shares	1 Months Ended	6 Months Ended
	Jul. 31, 2023	Jun. 30, 2023
Common Stock Oustanding [Roll Forward]
Shares outstanding, January 1, 2023 (in shares)	252,719,092	251,134,966
Shareowner Direct Plan (in shares)		228,017
Equity-based compensation plans (in shares)		134,334
Shares outstanding, June 30, 2023 (in shares)		252,719,092
At The Market Offering Program
Common Stock Oustanding [Roll Forward]
Equity-based compensation plans (in shares)		1,221,775
At The Market Offering Program | Subsequent Event [Member]
Common Stock Oustanding [Roll Forward]
Equity-based compensation plans (in shares)	172,701

XML

Common Equity (Changes in Shareowners' Equity) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance			$ 6,276
Beginning balance	$ 6,328	$ 6,077	6,276	$ 5,990
Net income attributable to common shareowners	160	159	323	351
Net income			323	351
Common stock dividends	(113)	(108)	(226)	(215)
At-the-market offering program and Shareowner Direct Plan issuances	70	6	76	13
Equity-based compensation plans and other	3	3	0	(2)
Other comprehensive income, net of tax	4		3
Contributions from noncontrolling interest		29	0	29
Ending balance	6,452		6,452
Ending balance	$ 6,452	$ 6,166	$ 6,452	$ 6,166
Common stock dividends (in dollars per share)	$ 0.4525	$ 0.4275	$ 0.905	$ 0.855
Common Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	$ 3	$ 3	$ 3	$ 3
At-the-market offering program and Shareowner Direct Plan issuances
Ending balance	3	3	3	3
Additional Paid-in Capital [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	2,780	2,750	2,777	2,749
At-the-market offering program and Shareowner Direct Plan issuances	70	6	76	13
Equity-based compensation plans and other	4	3	1	(3)
Ending balance	2,854	2,759	2,854	2,759
Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	3,559	3,336	3,509	3,250
Net income attributable to common shareowners	160	159	323	351
Common stock dividends	(113)	(108)	(226)	(215)
Equity-based compensation plans and other				1
Ending balance	3,606	3,387	3,606	3,387
Accumulated Other Comprehensive Income (Loss) [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	(1)	0	0	0
Other comprehensive income, net of tax	4		3
Ending balance	3	0	3	0
Shares in Deferred Compensation Trust [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	(13)	(12)	(13)	(12)
Equity-based compensation plans and other	(1)		(1)
Ending balance	(14)	(12)	(14)	(12)
Noncontrolling Interest [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	0	0	0	0
Contributions from noncontrolling interest		29		29
Ending balance	0	29	0	29
IPL [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance			3,808
Beginning balance	3,810	3,775	3,808	3,769
Net income	89	87	161	173
Common stock dividends	(70)	(80)	(140)	(160)
Capital contributions from parent	40		40	0
Ending balance	3,869		3,869
Ending balance	3,869	3,782	3,869	3,782
IPL [Member] | Common Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	33	33	33	33
Ending balance	33	33	33	33
IPL [Member] | Additional Paid-in Capital [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	2,807	2,807	2,807	2,807
Capital contributions from parent	40		40
Ending balance	2,847	2,807	2,847	2,807
IPL [Member] | Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	970	935	968	929
Net income	89	87	161	173
Common stock dividends	(70)	(80)	(140)	(160)
Ending balance	989	942	989	942
WPL [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance			3,491
Beginning balance	3,713	3,051	3,491	2,823
Net income	72	63	160	156
Common stock dividends	(46)	(44)	(92)	(89)
Equity-based compensation plans and other		(1)		(1)
Capital contributions from parent		85	180	265
Contributions from noncontrolling interest		29	0	29
Ending balance	3,739		3,739
Ending balance	3,739	3,183	3,739	3,183
WPL [Member] | Common Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	66	66	66	66
Ending balance	66	66	66	66
WPL [Member] | Additional Paid-in Capital [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	2,413	1,884	2,233	1,704
Equity-based compensation plans and other		(1)		(1)
Capital contributions from parent		85	180	265
Ending balance	2,413	1,968	2,413	1,968
WPL [Member] | Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	1,234	1,101	1,192	1,053
Net income	72	63	160	156
Common stock dividends	(46)	(44)	(92)	(89)
Ending balance	1,260	1,120	1,260	1,120
WPL [Member] | Noncontrolling Interest [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	0	0	0	0
Contributions from noncontrolling interest		29		29
Ending balance	$ 0	$ 29	$ 0	$ 29

XML

Debt (Narrative) (Details)	6 Months Ended
	Jun. 30, 2023 USD ($) Integer $ / shares shares	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Debt [Line Items]
Line of credit facility, current borrowing capacity	$ 1,000,000,000
Payments to retire long-term debt	404,000,000	$ 304,000,000
Long-term commercial paper	$ 55,000,000
Long-term commercial paper, percent	5.00%
Long-term debt, fair value	$ 7,951,000,000		$ 7,339,000,000
Parent Company [Member]
Debt [Line Items]
Line of credit facility, current borrowing capacity	450,000,000
IPL [Member]
Debt [Line Items]
Line of credit facility, current borrowing capacity	250,000,000
Long-term commercial paper	$ 55,000,000
Long-term commercial paper, percent	5.00%
Long-term debt, fair value	$ 3,321,000,000		3,228,000,000
WPL [Member]
Debt [Line Items]
Line of credit facility, current borrowing capacity	300,000,000
Long-term debt, fair value	2,875,000,000		$ 2,542,000,000
Term Loan Credit Agreement [Member] | Term loan credit agreement through March 2024 [Member] | Alliant Energy Finance LLC [Member]
Debt [Line Items]
Long-term debt	50,000,000
Senior Notes [Member] | 3.75% senior notes, due 2023 [Member] | Alliant Energy Finance LLC [Member]
Debt [Line Items]
Payments to retire long-term debt	$ 400,000,000
Interest rate, percent	3.75%
Debentures [Member] | 4.95% debenture, due 2033 [Member] | WPL [Member]
Debt [Line Items]
Long-term debt	$ 300,000,000
Interest rate, percent	4.95%
Convertible Senior Notes [Member]
Debt [Line Items]
Trading days | Integer	20
Trading days consecutive | Integer	30
Convertible Senior Notes [Member] | 3.875% convertible senior notes, due 2026 [Member]
Debt [Line Items]
Long-term debt	$ 575,000,000
Interest rate, percent	3.875%
Trading days | Integer	5
Trading days consecutive | Integer	10
Principal amount of Notes conversion rate applied to	$ 1,000
Initial conversion ratio	15.5461
Initial conversion price | $ / shares	$ 64.32
Fundamental change repurchase conversion price, percent	100.00%
Long-term debt, carrying value	$ 566,000,000
Unamortized debt issuance costs	9,000,000
Long-term debt, fair value	$ 573,000,000
Shares included in diluted earnings per share (in shares) | shares	0
Convertible Senior Notes [Member] | 3.875% convertible senior notes, due 2026 [Member] | Maximum [Member]
Debt [Line Items]
Conversion price, percent	130.00%
Convertible Senior Notes [Member] | 3.875% convertible senior notes, due 2026 [Member] | Minimum [Member]
Debt [Line Items]
Conversion price, percent	98.00%

XML

Debt (Credit Facilities) (Details) $ in Millions	Jun. 30, 2023 USD ($)
Debt [Line Items]
Amount outstanding	$ 391
Weighted average interest rates	5.30%
Available credit facility capacity	$ 554
IPL [Member]
Debt [Line Items]
Amount outstanding	$ 0
Weighted average interest rates	0.00%
Available credit facility capacity	$ 195
WPL [Member]
Debt [Line Items]
Amount outstanding	$ 44
Weighted average interest rates	5.20%
Available credit facility capacity	$ 256

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Debt (Other Short-Term Borrowings) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Debt [Line Items]
Maximum amount outstanding (based on daily outstanding balances)	$ 391	$ 441	$ 793	$ 577
Average amount outstanding (based on daily outstanding balances)	$ 88	$ 337	$ 330	$ 390
Weighted average interest rates	5.30%	1.00%	4.80%	0.60%
IPL [Member]
Debt [Line Items]
Maximum amount outstanding (based on daily outstanding balances)	$ 70	$ 0	$ 70	$ 0
Average amount outstanding (based on daily outstanding balances)	$ 6	$ 0	$ 3	$ 0
Weighted average interest rates	5.30%	0.00%	5.30%	0.00%
WPL [Member]
Debt [Line Items]
Maximum amount outstanding (based on daily outstanding balances)	$ 91	$ 222	$ 349	$ 252
Average amount outstanding (based on daily outstanding balances)	$ 18	$ 166	$ 160	$ 185
Weighted average interest rates	5.20%	0.90%	4.80%	0.50%

XML

Revenue (Disaggregation of Revenues) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 912	$ 943	$ 1,990	$ 2,012
Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	799	812	1,567	1,586
Electric [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	284	289	569	581
Electric [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	201	196	385	386
Electric [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	245	244	460	453
Electric [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	49	54	95	101
Electric [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	20	29	58	65
Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	77	94	353	356
Gas [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	42	51	210	210
Gas [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	22	27	110	109
Gas [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3	3	9	11
Gas [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10	13	24	26
Other Utility [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	13	13	25	23
Other Utility [Member] | Steam [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	11	11	22	20
Other Utility [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2	2	3	3
Non-utility and Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	23	24	45	47
Non-utility and Other [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	23	24	45	47
IPL [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	487	506	1,037	1,056
IPL [Member] | Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	431	442	819	843
IPL [Member] | Electric [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	151	158	294	308
IPL [Member] | Electric [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	129	127	241	246
IPL [Member] | Electric [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	130	136	236	246
IPL [Member] | Electric [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	14	16	26	31
IPL [Member] | Electric [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7	5	22	12
IPL [Member] | Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	44	52	194	191
IPL [Member] | Gas [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	24	28	117	113
IPL [Member] | Gas [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	12	14	56	54
IPL [Member] | Gas [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2	2	6	7
IPL [Member] | Gas [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6	8	15	17
IPL [Member] | Other Utility [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	12	12	24	22
IPL [Member] | Other Utility [Member] | Steam [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	11	11	22	20
IPL [Member] | Other Utility [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	1	2	2
WPL [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	402	413	908	909
WPL [Member] | Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	368	370	748	743
WPL [Member] | Electric [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	133	131	275	273
WPL [Member] | Electric [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	72	69	144	140
WPL [Member] | Electric [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	115	108	224	207
WPL [Member] | Electric [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	35	38	69	70
WPL [Member] | Electric [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	13	24	36	53
WPL [Member] | Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	33	42	159	165
WPL [Member] | Gas [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	18	23	93	97
WPL [Member] | Gas [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10	13	54	55
WPL [Member] | Gas [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	1	3	4
WPL [Member] | Gas [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4	5	9	9
WPL [Member] | Other Utility [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	1	1	1
WPL [Member] | Other Utility [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 1	$ 1	$ 1	$ 1

XML

Income Taxes (Schedule Of Effective Income Tax Rates) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Effective Tax Rate [Line Items]
Overall income tax rate	0.00%	2.00%	(1.00%)	3.00%
IPL [Member]
Effective Tax Rate [Line Items]
Overall income tax rate	(17.00%)	(16.00%)	(18.00%)	(15.00%)
WPL [Member]
Effective Tax Rate [Line Items]
Overall income tax rate	16.00%	18.00%	14.00%	18.00%

XML

Income Taxes (Summary Of Tax Credit Carryforwards) (Details) $ in Millions	Jun. 30, 2023 USD ($)
State [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	$ 503
Federal [Member]
Carryforwards [Line Items]
Tax credits, carryforward amount	708
IPL [Member] | State [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	8
IPL [Member] | Federal [Member]
Carryforwards [Line Items]
Tax credits, carryforward amount	485
WPL [Member] | State [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	1
WPL [Member] | Federal [Member]
Carryforwards [Line Items]
Tax credits, carryforward amount	$ 214

XML

Benefit Plans (Narrative) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2023 USD ($) shares
Defined Benefit Plan Disclosure [Line Items]
Unrecognized compensation cost	$ 15
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized compensation cost recognized over a weighted average period	1 year
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized compensation cost recognized over a weighted average period	2 years
IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized compensation cost	$ 8
WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized compensation cost	$ 6
Omnibus Incentive Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Shares included in diluted earnings per share (in shares) | shares	206,177

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Benefit Plans (Defined Benefit Pension And Other Postretirement Benefits Plans) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1	$ 2	$ 2	$ 4
Interest cost	12	9	23	18
Expected return on plan assets	(13)	(17)	(26)	(34)
Amortization of actuarial loss	7	8	14	16
Total	7	2	13	4
OPEB Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	1	1	2
Interest cost	2	2	4	3
Expected return on plan assets	(1)	(2)	(2)	(3)
Amortization of actuarial loss	1	0	1	1
Total	2	1	4	3
IPL [Member] | Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	2	3
Interest cost	5	4	10	8
Expected return on plan assets	(6)	(8)	(13)	(16)
Amortization of actuarial loss	3	4	6	7
Total	3	1	5	2
IPL [Member] | OPEB Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	1	0	1
Interest cost	1	0	2	1
Expected return on plan assets	(1)	(1)	(2)	(2)
Amortization of actuarial loss	1	0	1	0
Total	1	0	1	0
WPL [Member] | Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	1	2
Interest cost	5	4	10	8
Expected return on plan assets	(6)	(8)	(11)	(16)
Amortization of actuarial loss	4	4	7	8
Total	4	1	7	2
WPL [Member] | OPEB Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	1	0	2	1
Expected return on plan assets	0	0	0	0
Amortization of actuarial loss	0	1	0	1
Total	$ 1	$ 1	$ 2	$ 2

XML

Benefit Plans (Recognized Compensation Expense And Income Tax Benefits) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Compensation expense	$ 3	$ 3	$ 6	$ 7
Income tax benefits	1	1	2	2
IPL [Member]
Compensation expense	2	1	3	4
Income tax benefits	0	0	1	1
WPL [Member]
Compensation expense	1	1	2	3
Income tax benefits	$ 0	$ 0	$ 1	$ 1

XML

Benefit Plans (Summary Of Equity-based Compensation Plans Grants) (Details)	6 Months Ended
	Jun. 30, 2023 $ / shares shares
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants (in shares/units) | shares	106,927
Weighted average grant date fair value (in dollars per share/unit) | $ / shares	$ 55.68
Performance Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants (in shares/units) | shares	122,178
Weighted average grant date fair value (in dollars per share/unit) | $ / shares	$ 52.77
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants (in shares/units) | shares	104,849
Weighted average grant date fair value (in dollars per share/unit) | $ / shares	$ 52.81

XML

Derivative Instruments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Derivative Instruments [Line Items]
Non-current interest rate swap liabilities	$ 534		$ 534		$ 518
Accumulated other comprehensive loss, interest rate swap	3		3		$ 0
Interest expense, interest rate swap	96	$ 78	190	$ 152
Alliant Energy Finance LLC [Member] | Interest Rate Swap [Member] | Term Loan Credit Agreement [Member]
Derivative Instruments [Line Items]
Interest rate swap	$ 300		$ 300
Interest rate swap, fixed interest rate percentage	3.93%		3.93%
Non-current interest rate swap liabilities	$ 4		$ 4
Accumulated other comprehensive loss, interest rate swap	3		3
Interest expense, interest rate swap	$ 1		$ 1

XML

Derivative Instruments (Notional Amounts Of Derivative Instruments) (Details) - Commodity [Member] T in Thousands, MWh in Thousands, Dekatherms in Thousands	6 Months Ended
	Jun. 30, 2023 Dekatherms MWh T
Electricity (MWhs) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	1,171
Electricity (MWhs) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	537
Electricity (MWhs) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	634
FTRs (MWhs) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	24,874
FTRs (MWhs) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	10,163
FTRs (MWhs) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	14,711
Natural Gas (Dths) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Dths) | Dekatherms	192,421
Natural Gas (Dths) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Dths) | Dekatherms	92,087
Natural Gas (Dths) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Dths) | Dekatherms	100,334
Coal (Tons) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Tons) | T	466
Coal (Tons) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Tons) | T	224
Coal (Tons) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Tons) | T	242

XML

Derivative Instruments (Fair Value Of Financial Instruments) (Details) - Commodity Contracts [Member] - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Current derivative assets	$ 86	$ 111
Non-current derivative assets	61	126
Current derivative liabilities	54	59
Non-current derivative liabilities	43	20
IPL [Member]
Derivatives, Fair Value [Line Items]
Current derivative assets	61	69
Non-current derivative assets	34	69
Current derivative liabilities	27	40
Non-current derivative liabilities	10	6
WPL [Member]
Derivatives, Fair Value [Line Items]
Current derivative assets	25	42
Non-current derivative assets	27	57
Current derivative liabilities	27	19
Non-current derivative liabilities	$ 33	$ 14

XML

Derivative Instruments (Balance Sheet Offsetting) (Details) - Commodity Contracts [Member] - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Derivative Instruments [Line Items]
Derivative assets, Gross (as reported)	$ 147	$ 237
Derivative assets, Net	114	193
Derivative liabilities, Gross (as reported)	97	79
Derivative liabilities, Net	64	35
IPL [Member]
Derivative Instruments [Line Items]
Derivative assets, Gross (as reported)	95	138
Derivative assets, Net	73	108
Derivative liabilities, Gross (as reported)	37	46
Derivative liabilities, Net	15	16
WPL [Member]
Derivative Instruments [Line Items]
Derivative assets, Gross (as reported)	52	99
Derivative assets, Net	41	85
Derivative liabilities, Gross (as reported)	60	33
Derivative liabilities, Net	$ 49	$ 19

XML

Fair Value Measurements (Fair Value Measurements) (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Assets:
Money market fund investments	$ 6	$ 10
Deferred proceeds	175	185
Liabilities:
Long-term debt (incl. current maturities)	7,951	7,339
IPL [Member]
Assets:
Money market fund investments	6	10
Deferred proceeds	175	185
Liabilities:
Long-term debt (incl. current maturities)	3,321	3,228
WPL [Member]
Liabilities:
Long-term debt (incl. current maturities)	2,875	2,542
Commodity Contracts [Member]
Assets:
Derivatives	147	237
Liabilities:
Derivatives	97	79
Commodity Contracts [Member] | IPL [Member]
Assets:
Derivatives	95	138
Liabilities:
Derivatives	37	46
Commodity Contracts [Member] | WPL [Member]
Assets:
Derivatives	52	99
Liabilities:
Derivatives	60	33
Interest Rate Swap [Member]
Assets:
Derivatives	4	0
Level 1 [Member]
Assets:
Money market fund investments	6	10
Deferred proceeds	0	0
Liabilities:
Long-term debt (incl. current maturities)	0	0
Level 1 [Member] | IPL [Member]
Assets:
Money market fund investments	6	10
Deferred proceeds	0	0
Liabilities:
Long-term debt (incl. current maturities)	0	0
Level 1 [Member] | WPL [Member]
Liabilities:
Long-term debt (incl. current maturities)	0	0
Level 1 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	0	0
Liabilities:
Derivatives	0	0
Level 1 [Member] | Commodity Contracts [Member] | IPL [Member]
Assets:
Derivatives	0	0
Liabilities:
Derivatives	0	0
Level 1 [Member] | Commodity Contracts [Member] | WPL [Member]
Assets:
Derivatives	0	0
Liabilities:
Derivatives	0	0
Level 1 [Member] | Interest Rate Swap [Member]
Assets:
Derivatives	0	0
Level 2 [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	0	0
Liabilities:
Long-term debt (incl. current maturities)	7,950	7,338
Level 2 [Member] | IPL [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	0	0
Liabilities:
Long-term debt (incl. current maturities)	3,321	3,228
Level 2 [Member] | WPL [Member]
Liabilities:
Long-term debt (incl. current maturities)	2,875	2,542
Level 2 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	80	206
Liabilities:
Derivatives	84	67
Level 2 [Member] | Commodity Contracts [Member] | IPL [Member]
Assets:
Derivatives	44	111
Liabilities:
Derivatives	27	35
Level 2 [Member] | Commodity Contracts [Member] | WPL [Member]
Assets:
Derivatives	36	95
Liabilities:
Derivatives	57	32
Level 2 [Member] | Interest Rate Swap [Member]
Assets:
Derivatives	4	0
Level 3 [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	175	185
Liabilities:
Long-term debt (incl. current maturities)	1	1
Level 3 [Member] | IPL [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	175	185
Liabilities:
Long-term debt (incl. current maturities)	0	0
Level 3 [Member] | WPL [Member]
Liabilities:
Long-term debt (incl. current maturities)	0	0
Level 3 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	67	31
Liabilities:
Derivatives	13	12
Level 3 [Member] | Commodity Contracts [Member] | IPL [Member]
Assets:
Derivatives	51	27
Liabilities:
Derivatives	10	11
Level 3 [Member] | Commodity Contracts [Member] | WPL [Member]
Assets:
Derivatives	16	4
Liabilities:
Derivatives	3	1
Level 3 [Member] | Interest Rate Swap [Member]
Assets:
Derivatives	0	0
Carrying Amount [Member]
Assets:
Money market fund investments	6	10
Deferred proceeds	175	185
Liabilities:
Long-term debt (incl. current maturities)	8,595	8,076
Carrying Amount [Member] | IPL [Member]
Assets:
Money market fund investments	6	10
Deferred proceeds	175	185
Liabilities:
Long-term debt (incl. current maturities)	3,702	3,646
Carrying Amount [Member] | WPL [Member]
Liabilities:
Long-term debt (incl. current maturities)	3,068	2,770
Carrying Amount [Member] | Commodity Contracts [Member]
Assets:
Derivatives	147	237
Liabilities:
Derivatives	97	79
Carrying Amount [Member] | Commodity Contracts [Member] | IPL [Member]
Assets:
Derivatives	95	138
Liabilities:
Derivatives	37	46
Carrying Amount [Member] | Commodity Contracts [Member] | WPL [Member]
Assets:
Derivatives	52	99
Liabilities:
Derivatives	60	33
Carrying Amount [Member] | Interest Rate Swap [Member]
Assets:
Derivatives	$ 4	$ 0

XML

Fair Value Measurements (Fair Value Measurements Using Significant Unobservable Inputs) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Commodity Contracts [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ (5)	$ 10	$ 19	$ 29
Total net gains (losses) included in changes in net assets (realized/unrealized)	(7)	(10)	(11)	(16)
Purchases	62	79	62	79
Sales	(1)	0	(1)	0
Settlements	5	(7)	(15)	(20)
Ending balance	54	72	54	72
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 June 30	(7)	(10)	(11)	(16)
Commodity Contracts [Member] | IPL [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	0	7	16	18
Total net gains (losses) included in changes in net assets (realized/unrealized)	(13)	(3)	(12)	(7)
Purchases	51	58	51	58
Sales	(1)	0	(1)	0
Settlements	4	(4)	(13)	(11)
Ending balance	41	58	41	58
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 June 30	(13)	(3)	(12)	(8)
Commodity Contracts [Member] | WPL [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(5)	3	3	11
Total net gains (losses) included in changes in net assets (realized/unrealized)	6	(7)	1	(9)
Purchases	11	21	11	21
Settlements	1	(3)	(2)	(9)
Ending balance	13	14	13	14
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 June 30	6	(7)	1	(8)
Deferred Proceeds [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	153	227	185	214
Total net gains (losses) included in changes in net assets (realized/unrealized)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	22	17	(10)	30
Ending balance	175	244	175	244
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 June 30	0	0	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	153	227	185	214
Total net gains (losses) included in changes in net assets (realized/unrealized)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	22	17	(10)	30
Ending balance	175	244	175	244
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 June 30	$ 0	$ 0	$ 0	$ 0

XML

Fair Value Measurements (Fair Value Of Net Derivative Assets (Liabilities)) (Details) - Commodity Contracts [Member] - USD ($) $ in Millions	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	$ 54	$ (5)	$ 19	$ 72	$ 10	$ 29
Excluding Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative liabilities	(8)		(10)
Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	62		29
IPL [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	41	0	16	58	7	18
IPL [Member] | Excluding Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative liabilities	(5)		(9)
IPL [Member] | Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	46		25
WPL [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	13	$ (5)	3	$ 14	$ 3	$ 11
WPL [Member] | Excluding Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative liabilities	(3)		(1)
WPL [Member] | Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	$ 16		$ 4

XML

Commitments And Contingencies (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended	9 Months Ended
	Jun. 30, 2023	Sep. 30, 2021	Sep. 30, 2020
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 1,352
IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	624
WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	698
Capital Purchase Commitment [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	188
Capital Purchase Commitment [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	87
Capital Purchase Commitment [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	101
Indemnification Agreement [Member]
Commitments and Contingencies [Line Items]
Obligations, maximum	59
Indemnification Agreement [Member] | Purchased Power [Member]
Commitments and Contingencies [Line Items]
Obligations, maximum	$ 17
Whiting Petroleum Affiliate [Member]
Commitments and Contingencies [Line Items]
Partnership share, percent	6.00%
Obligations, maximum	$ 58
Credit loss liability	$ 5
Federal Energy Regulatory Commission [Member]
Commitments and Contingencies [Line Items]
MISO base return on equity, percentage		10.02%	9.88%

XML

Commitments And Contingencies (Other Purchase Commitments) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2023 USD ($)
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 1,352
Individual commitments incurred	1
IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	624
Individual commitments incurred	1
WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	698
Individual commitments incurred	1
Natural gas [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	1,083
Natural gas [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	494
Natural gas [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	589
Coal [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	163
Coal [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	79
Coal [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	84
Other [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	106
Other [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	51
Other [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 25

XML

Commitments And Contingencies (MPG Site Estimated Future Costs And Recorded Liabilities) (Details) - Natural Gas Processing Plant [Member] $ in Millions	6 Months Ended
	Jun. 30, 2023 USD ($)
Commitments and Contingencies [Line Items]
Current and non-current environmental liabilities	$ 18
IPL [Member]
Commitments and Contingencies [Line Items]
Current and non-current environmental liabilities	8
WPL [Member]
Commitments and Contingencies [Line Items]
Current and non-current environmental liabilities	10
Minimum [Member]
Commitments and Contingencies [Line Items]
Range of estimated future costs	9
Minimum [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Range of estimated future costs	5
Minimum [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Range of estimated future costs	4
Maximum [Member]
Commitments and Contingencies [Line Items]
Range of estimated future costs	36
Maximum [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Range of estimated future costs	11
Maximum [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Range of estimated future costs	$ 25

XML

Segments Of Business (Schedule Of Segments Of Business) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Revenues	$ 912	$ 943	$ 1,990	$ 2,012
Operating income	217	212	439	460
Net income (loss) attributable to common shareowners	160	159	323	351
Net income			323	351
IPL [Member]
Segment Reporting Information [Line Items]
Revenues	487	506	1,037	1,056
Operating income	110	109	206	218
Net income	89	87	161	173
WPL [Member]
Segment Reporting Information [Line Items]
Revenues	402	413	908	909
Operating income	99	95	220	227
Net income	72	63	160	156
Electric [Member]
Segment Reporting Information [Line Items]
Revenues	799	812	1,567	1,586
Operating income	200	195	363	376
Electric [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	431	442	819	843
Operating income	105	104	171	179
Electric [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	368	370	748	743
Operating income	95	91	192	197
Gas [Member]
Segment Reporting Information [Line Items]
Revenues	77	94	353	356
Operating income	2	8	52	65
Gas [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	44	52	194	191
Operating income	0	4	27	36
Gas [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	33	42	159	165
Operating income	2	4	25	29
Other Utility [Member]
Segment Reporting Information [Line Items]
Revenues	13	13	25	23
Operating income	7	1	11	4
Other Utility [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	12	12	24	22
Operating income	5	1	8	3
Other Utility [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	1	1	1	1
Operating income	2	0	3	1
Utility Business [Member]
Segment Reporting Information [Line Items]
Revenues	889	919	1,945	1,965
Operating income	209	204	426	445
Net income (loss) attributable to common shareowners	161	150	321	329
ATC Holdings, Non-Utility, Parent and Other [Member]
Segment Reporting Information [Line Items]
Revenues	23	24	45	47
Operating income	8	8	13	15
Net income (loss) attributable to common shareowners	$ (1)	$ 9	$ 2	$ 22

XML

Related Parties (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
WPL [Member] | WPL Owed ATC LLC [Member] | Related Party [Member]
Related Party Transactions [Line Items]
Net amounts owed	$ 10	$ 10

XML

Related Parties (Service Agreements) (Details) - Corporate Services [Member] - Subsidiary of Common Parent [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Corporate Services Billings [Member] | IPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	$ 48	$ 51	$ 88	$ 91
Corporate Services Billings [Member] | WPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	43	42	80	78
Sales Credited [Member] | IPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	1	0	8	0
Sales Credited [Member] | WPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	10	13	22	31
Purchases Billed [Member] | IPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	94	129	187	223
Purchases Billed [Member] | WPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	$ 2	$ 39	$ 17	$ 61

XML

Related Parties (Net Intercompany Payables) (Details) - Subsidiary of Common Parent [Member] - Corporate Services [Member] - Related Party [Member] - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
IPL [Member]
Related Party Transactions [Line Items]
Net amounts owed	$ 116	$ 103
WPL [Member]
Related Party Transactions [Line Items]
Net amounts owed	$ 73	$ 56

XML

Related Parties (Amounts Billed Between Parties) (Details) - ATC LLC [Member] - WPL [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
ATC Billings To WPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	$ 44	$ 35	$ 78	$ 69
WPL Billings To ATC [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	$ 5	$ 5	$ 11	$ 8