10-Q

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 September 30, 2020

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

Interstate Power and Light Company, 5.100% Series D Cumulative Perpetual Preferred Stock, $0.01 Par Value, Trading Symbol IPLDP, Nasdaq Global Select Market

Indicate by check mark whether the registrants (1) have filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrants were required to file such reports), and (2) have 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 registrants have 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 registrants were 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 registrants are large accelerated filers, accelerated filers, non-accelerated filers, smaller reporting companies, or emerging growth companies. 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 registrants are shell companies (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 September 30, 2020:

Alliant Energy Corporation, Common Stock, $0.01 par value, 249,760,663 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

	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	13
3. Receivables	14
4. Investments	14
5. Common Equity	15
6. Debt	17
7. Revenues	18
8. Income Taxes	19
9. Benefit Plans	19
10. Asset Retirement Obligations	20
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	36
Item 4. Controls and Procedures	37
Part II. Other Information	37
Item 1A. Risk Factors	37
Item 2. Unregistered Sales of Equity Securities and Use of Proceeds	38
Item 6. Exhibits	38
Signatures	39

DEFINITIONS

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

Abbreviation or Acronym	Definition	Abbreviation or Acronym	Definition
2019 Form 10-K	Combined Annual Report on Form 10-K filed by Alliant Energy, IPL and WPL for the year ended Dec. 31, 2019	GAAP	U.S. generally accepted accounting principles
AEF	Alliant Energy Finance, LLC	IPL	Interstate Power and Light Company
Alliant Energy	Alliant Energy Corporation	IUB	Iowa Utilities Board
ATC	American Transmission Company LLC	MDA	Management’s Discussion and Analysis of Financial Condition and Results of Operations
ATC Holdings	Interest in American Transmission Company LLC and ATC Holdco LLC	MISO	Midcontinent Independent System Operator, Inc.
Corporate Services	Alliant Energy Corporate Services, Inc.	MW	Megawatt
COVID-19	Novel coronavirus	MWh	Megawatt-hour
DAEC	Duane Arnold Energy Center	N/A	Not applicable
Dth	Dekatherm	Note(s)	Combined Notes to Condensed Consolidated Financial Statements
EGU	Electric generating unit	OPEB	Other postretirement benefits
EPA	U.S. Environmental Protection Agency	PPA	Purchased power agreement
EPS	Earnings per weighted average common share	PSCW	Public Service Commission of Wisconsin
Federal Tax Reform	Tax Cuts and Jobs Act	U.S.	United States of America
FERC	Federal Energy Regulatory Commission	West Riverside	West Riverside Energy Center
Financial Statements	Condensed Consolidated Financial Statements	Whiting Petroleum	Whiting Petroleum Corporation
FTR	Financial transmission right	WPL	Wisconsin Power and Light Company

FORWARD-LOOKING STATEMENTS

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

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

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

• the direct or indirect effects resulting from the COVID-19 pandemic on sales volumes, margins, operations, employees, contractors, vendors, the ability to complete construction projects, supply chains, customers’ inability to pay bills, suspension of disconnects and waiving of late fees applied to past due accounts, the market value of the assets that fund pension plans and the potential for additional funding requirements, the ability of counterparties to meet their obligations, compliance with regulatory requirements, the ability to implement regulatory plans, economic conditions and access to capital markets;

• 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;

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

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

• 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;

• 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;

1

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

• weather effects on results of utility operations;

• issues associated with environmental remediation and environmental compliance, including compliance with all environmental and emissions permits, the Coal Combustion Residuals Rule, future changes in environmental laws and regulations, including federal, state or local regulations for carbon dioxide emissions reductions from new and existing fossil-fueled EGUs, and litigation associated with environmental requirements;

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

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

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

• inflation and interest rates;

• the ability to complete construction of solar projects within the cost caps set by regulators and to meet all requirements to qualify for the full level of renewable tax credits;

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

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

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

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

• impacts that excessive heat, storms or natural disasters may have on Alliant Energy’s, IPL’s and WPL’s operations and recovery of costs associated with restoration activities, including those related to the August 2020 derecho windstorm, or on the operations of Alliant Energy’s investments;

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

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

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

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

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

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

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

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

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

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

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

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

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

• other factors listed in MDA and Item 1A Risk Factors, as well as Risk Factors in Item 1A in the 2019 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.

2

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 Nine Months
	Ended September 30,						Ended September 30,
	2020			2019			2020			2019
	(in millions, except per share amounts)
Revenues:
Electric utility		$852			$916			$2,257			$2,350
Gas utility	42			42			253			323
Other utility	10			11			32			33
Non-utility	16			21			57			62
Total revenues	920			990			2,599			2,768
Operating expenses:
Electric production fuel and purchased power	179			219			527			602
Electric transmission service	132			127			326			363
Cost of gas sold	11			9			117			151
Other operation and maintenance	143			174			465			527
Depreciation and amortization	156			144			454			424
Taxes other than income taxes	27			27			82			84
Total operating expenses	648			700			1,971			2,151
Operating income	272			290			628			617
Other (income) and deductions:
Interest expense	68			68			207			204
Equity income from unconsolidated investments, net	(15		)	(12		)	(46		)	(35		)
Allowance for funds used during construction	(13		)	(22		)	(51		)	(66		)
Other	3			4			7			11
Total other (income) and deductions	43			38			117			114
Income before income taxes	229			252			511			503
Income tax expense (benefit)	(20		)	23			(47		)	49
Net income	249			229			558			454
Preferred dividend requirements of Interstate Power and Light Company	3			3			8			8
Net income attributable to Alliant Energy common shareowners		$246			$226			$550			$446
Weighted average number of common shares outstanding:
Basic	249.7			239.1			247.9			237.7
Diluted	250.0			239.9			248.1			238.2
Earnings per weighted average common share attributable to Alliant Energy common shareowners:
Basic		$0.99			$0.95			$2.22			$1.88
Diluted		$0.98			$0.94			$2.22			$1.87

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

3

ALLIANT ENERGY CORPORATION

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)

	September 30, 2020		December 31, 2019
	(in millions, except per share and share amounts)
ASSETS
Current assets:
Cash and cash equivalents		$189		$16
Accounts receivable, less allowance for expected credit losses	399		402
Production fuel, at weighted average cost	62		78
Gas stored underground, at weighted average cost	48		49
Materials and supplies, at weighted average cost	113		100
Regulatory assets	74		87
Prepaid gross receipts tax	30		42
Other	118		102
Total current assets	1,033		876
Property, plant and equipment, net	14,199		13,527
Investments:
ATC Holdings	328		320
Other	150		148
Total investments	478		468
Other assets:
Regulatory assets	1,762		1,758
Deferred charges and other	68		72
Total other assets	1,830		1,830
Total assets		$17,540		$16,701

LIABILITIES AND EQUITY
Current liabilities:
Current maturities of long-term debt		$7			$657
Commercial paper	422			337
Accounts payable	417			422
Regulatory liabilities	163			212
Other	286			426
Total current liabilities	1,295			2,054
Long-term debt, net (excluding current portion)	6,574			5,533
Other liabilities:
Deferred tax liabilities	1,803			1,714
Regulatory liabilities	1,188			1,212
Pension and other benefit obligations	423			484
Other	348			299
Total other liabilities	3,762			3,709
Commitments and contingencies (Note 13)
Equity:
Alliant Energy Corporation common equity:
Common stock - $0.01 par value - 480,000,000 shares authorized; 249,760,663 and 245,022,800 shares	2			2
Additional paid-in capital	2,693			2,446
Retained earnings	3,026			2,766
Accumulated other comprehensive income (loss)	(1		)	1
Shares in deferred compensation trust - 374,246 and 381,232 shares at a weighted average cost of $28.28 and $26.24 per share	(11		)	(10		)
Total Alliant Energy Corporation common equity	5,709			5,205
Cumulative preferred stock of Interstate Power and Light Company	200			200
Total equity	5,909			5,405
Total liabilities and equity		$17,540			$16,701

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

4

ALLIANT ENERGY CORPORATION

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

	For the Nine Months
	Ended September 30,
	2020			2019
	(in millions)
Cash flows from operating activities:
Net income		$558			$454
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	454			424
Deferred tax expense (benefit) and tax credits	(48		)	53
Equity component of allowance for funds used during construction	(36		)	(46		)
Other	19			17
Other changes in assets and liabilities:
Accounts receivable	(316		)	(359		)
Regulatory liabilities	(72		)	(12		)
Deferred income taxes	143			45
Pension and other benefit obligations	(61		)	(33		)
DAEC PPA amendment buyout payment	(110		)	—
Other	(95		)	(34		)
Net cash flows from operating activities	436			509
Cash flows used for investing activities:
Construction and acquisition expenditures:
Utility business	(935		)	(1,004		)
Other	(39		)	(71		)
Cash receipts on sold receivables	318			256
Other	(23		)	(42		)
Net cash flows used for investing activities	(679		)	(861		)
Cash flows from financing activities:
Common stock dividends	(281		)	(253		)
Proceeds from issuance of common stock, net	241			185
Proceeds from issuance of long-term debt	1,050			950
Payments to retire long-term debt	(654		)	(253		)
Net change in commercial paper	85			(92		)
Other	(22		)	(11		)
Net cash flows from financing activities	419			526
Net increase in cash, cash equivalents and restricted cash	176			174
Cash, cash equivalents and restricted cash at beginning of period	18			26
Cash, cash equivalents and restricted cash at end of period		$194			$200
Supplemental cash flows information:
Cash (paid) refunded during the period for:
Interest		($197	)		($195	)
Income taxes, net		$6			$1
Significant non-cash investing and financing activities:
Accrued capital expenditures		$202			$254
Beneficial interest obtained in exchange for securitized accounts receivable		$201			$237

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

5

INTERSTATE POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

	For the Three Months						For the Nine Months
	Ended September 30,						Ended September 30,
	2020			2019			2020			2019
	(in millions)
Revenues:
Electric utility		$519			$561			$1,332			$1,373
Gas utility	24			25			141			188
Steam and other	10			11			31			32
Total revenues	553			597			1,504			1,593
Operating expenses:
Electric production fuel and purchased power	102			127			304			339
Electric transmission service	93			92			212			257
Cost of gas sold	6			6			63			80
Other operation and maintenance	85			100			269			306
Depreciation and amortization	89			84			264			243
Taxes other than income taxes	16			14			45			46
Total operating expenses	391			423			1,157			1,271
Operating income	162			174			347			322
Other (income) and deductions:
Interest expense	35			32			104			93
Allowance for funds used during construction	(6		)	(11		)	(21		)	(34		)
Other	1			2			3			5
Total other (income) and deductions	30			23			86			64
Income before income taxes	132			151			261			258
Income tax expense (benefit)	(19		)	7			(37		)	11
Net income	151			144			298			247
Preferred dividend requirements	3			3			8			8
Net income available for common stock		$148			$141			$290			$239

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.

6

INTERSTATE POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)

	September 30, 2020		December 31, 2019
	(in millions, except per share and share amounts)
ASSETS
Current assets:
Cash and cash equivalents		$185		$9
Accounts receivable, less allowance for expected credit losses	219		203
Production fuel, at weighted average cost	45		47
Gas stored underground, at weighted average cost	21		22
Materials and supplies, at weighted average cost	63		55
Regulatory assets	52		44
Other	53		29
Total current assets	638		409
Property, plant and equipment, net	7,818		7,481
Other assets:
Regulatory assets	1,366		1,356
Deferred charges and other	36		31
Total other assets	1,402		1,387
Total assets		$9,858		$9,277

LIABILITIES AND EQUITY
Current liabilities:
Current maturities of long-term debt		$—		$200
Accounts payable	231		207
Regulatory liabilities	117		116
Other	198		307
Total current liabilities	546		830
Long-term debt, net (excluding current portion)	3,344		2,947
Other liabilities:
Deferred tax liabilities	1,028		1,008
Regulatory liabilities	574		599
Pension and other benefit obligations	149		168
Other	287		253
Total other liabilities	2,038		2,028
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	2,693		2,348
Retained earnings	1,004		891
Total Interstate Power and Light Company common equity	3,730		3,272
Cumulative preferred stock	200		200
Total equity	3,930		3,472
Total liabilities and equity		$9,858		$9,277

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

7

INTERSTATE POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

	For the Nine Months
	Ended September 30,
	2020			2019
	(in millions)
Cash flows from operating activities:
Net income		$298			$247
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	264			243
Equity component of allowance for funds used during construction	(15		)	(25		)
Deferred tax benefit and tax credits	(42		)	(14		)
Other	6			2
Other changes in assets and liabilities:
Accounts receivable	(337		)	(365		)
Regulatory assets	(32		)	(13		)
Deferred income taxes	62			32
Pension and other benefit obligations	(19		)	(13		)
DAEC PPA amendment buyout payment	(110		)	—
Other	(56		)	45
Net cash flows from operating activities	19			139
Cash flows used for investing activities:
Construction and acquisition expenditures	(465		)	(696		)
Cash receipts on sold receivables	318			256
Other	(55		)	(44		)
Net cash flows used for investing activities	(202		)	(484		)
Cash flows from financing activities:
Common stock dividends	(177		)	(126		)
Capital contributions from parent	345			100
Proceeds from issuance of long-term debt	400			600
Payments to retire long-term debt	(200		)	—
Net change in commercial paper	—			(50		)
Other	(9		)	(6		)
Net cash flows from financing activities	359			518
Net increase in cash, cash equivalents and restricted cash	176			173
Cash, cash equivalents and restricted cash at beginning of period	9			12
Cash, cash equivalents and restricted cash at end of period		$185			$185
Supplemental cash flows information:
Cash (paid) refunded during the period for:
Interest		($109	)		($94	)
Income taxes, net		($12	)		$8
Significant non-cash investing and financing activities:
Accrued capital expenditures		$150			$180
Beneficial interest obtained in exchange for securitized accounts receivable		$201			$237

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

8

WISCONSIN POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

	For the Three Months						For the Nine Months
	Ended September 30,						Ended September 30,
	2020			2019			2020			2019
	(in millions)
Revenues:
Electric utility		$333			$355			$925			$977
Gas utility	18			17			112			135
Other	—			—			1			1
Total revenues	351			372			1,038			1,113
Operating expenses:
Electric production fuel and purchased power	78			92			223			263
Electric transmission service	39			36			114			106
Cost of gas sold	4			3			53			71
Other operation and maintenance	65			62			172			188
Depreciation and amortization	65			59			186			177
Taxes other than income taxes	11			12			35			35
Total operating expenses	262			264			783			840
Operating income	89			108			255			273
Other (income) and deductions:
Interest expense	26			25			78			77
Allowance for funds used during construction	(6		)	(11		)	(29		)	(31		)
Other	1			1			3			4
Total other (income) and deductions	21			15			52			50
Income before income taxes	68			93			203			223
Income tax expense (benefit)	(5		)	17			(17		)	40
Net income		$73			$76			$220			$183

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.

9

WISCONSIN POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)

	September 30, 2020		December 31, 2019
	(in millions, except per share and share amounts)
ASSETS
Current assets:
Cash and cash equivalents		$2		$4
Accounts receivable, less allowance for expected credit losses	170		191
Production fuel, at weighted average cost	17		31
Gas stored underground, at weighted average cost	27		27
Materials and supplies, at weighted average cost	48		43
Regulatory assets	22		43
Prepaid gross receipts tax	30		42
Other	22		62
Total current assets	338		443
Property, plant and equipment, net	5,977		5,638
Other assets:
Regulatory assets	396		402
Deferred charges and other	33		24
Total other assets	429		426
Total assets		$6,744		$6,507

LIABILITIES AND EQUITY
Current liabilities:
Current maturities of long-term debt		$—		$150
Commercial paper	139		168
Accounts payable	126		160
Regulatory liabilities	46		96
Other	117		116
Total current liabilities	428		690
Long-term debt, net (excluding current portion)	2,130		1,783
Other liabilities:
Deferred tax liabilities	696		626
Regulatory liabilities	614		613
Finance lease obligations - Sheboygan Falls Energy Facility	44		51
Pension and other benefit obligations	189		211
Other	161		169
Total other liabilities	1,704		1,670
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	1,459		1,434
Retained earnings	957		864
Total Wisconsin Power and Light Company common equity	2,482		2,364
Total liabilities and equity		$6,744		$6,507

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

10

WISCONSIN POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

	For the Nine Months
	Ended September 30,
	2020			2019
	(in millions)
Cash flows from operating activities:
Net income		$220			$183
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	186			177
Deferred tax expense (benefit) and tax credits	(9		)	55
Other	(8		)	(8		)
Other changes in assets and liabilities:
Regulatory liabilities	(61		)	(29		)
Deferred income taxes	79			16
Other	(5		)	(34		)
Net cash flows from operating activities	402			360
Cash flows used for investing activities:
Construction and acquisition expenditures	(470		)	(308		)
Other	5			(27		)
Net cash flows used for investing activities	(465		)	(335		)
Cash flows from (used for) financing activities:
Common stock dividends	(127		)	(108		)
Capital contributions from parent	25			100
Proceeds from issuance of long-term debt	350			350
Payments to retire long-term debt	(150		)	(250		)
Net change in commercial paper	(29		)	(105		)
Other	(8		)	(11		)
Net cash flows from (used for) financing activities	61			(24		)
Net increase (decrease) in cash, cash equivalents and restricted cash	(2		)	1
Cash, cash equivalents and restricted cash at beginning of period	4			9
Cash, cash equivalents and restricted cash at end of period		$2			$10
Supplemental cash flows information:
Cash (paid) refunded during the period for:
Interest		($71	)		($74	)
Income taxes, net		$5			($7	)
Significant non-cash investing and financing activities:
Accrued capital expenditures		$50			$70

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

11

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 Securities and Exchange Commission. 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 latest combined Annual Report on 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 nine months ended September 30, 2020 are not necessarily indicative of results that may be expected for the year ending December 31, 2020.

In March 2020, COVID-19 was declared a global pandemic, which has resulted in widespread travel restrictions, closures of commercial spaces and industrial facilities, and more people working from home in Alliant Energy’s service territories. For the three and nine months ended September 30, 2020, Alliant Energy, IPL and WPL considered the impact of COVID-19 on their overall business operations, financial condition, results of operations and cash flows, along with assumptions and estimates used. While the total expected impact of COVID-19 on future sales is currently unknown, Alliant Energy, IPL and WPL have experienced higher electric residential sales and lower electric commercial and industrial sales since the outset of the pandemic. The degree to which the COVID-19 pandemic may impact Alliant Energy, IPL and WPL in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities.

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 1(b) Cash and Cash Equivalents - At September 30, 2020, Alliant Energy’s and IPL’s cash and cash equivalents included $183 million and $183 million of money market fund investments, with weighted average interest rates of 0.1% and 0.1%, respectively.

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

NOTE 1(d) New Accounting Standards -

Credit Losses - In June 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 13(c) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s summary of changes in shareowners’ equity in Note 5 for the nine months ended September 30, 2020.

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NOTE 2. REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

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

	Alliant Energy				IPL				WPL
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Tax-related		$877		$818		$829		$777		$48		$41
Pension and OPEB costs	492		524		247		263		245		261
Assets retired early	118		134		79		88		39		46
Asset retirement obligations	115		112		79		76		36		36
IPL’s DAEC PPA amendment	110		108		110		108		—		—
Derivatives	20		39		8		18		12		21
Emission allowances	19		21		19		21		—		—
Other	85		89		47		49		38		40
		$1,836		$1,845		$1,418		$1,400		$418		$445

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

	Alliant Energy				IPL				WPL
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Tax-related		$746		$836		$334		$351		$412		$485
Cost of removal obligations	371		388		241		257		130		131
Electric transmission cost recovery	62		88		30		51		32		37
Derivatives	40		20		27		17		13		3
WPL’s West Riverside liquidated damages	36		—		—		—		36		—
Commodity cost recovery	22		24		19		9		3		15
WPL’s earnings sharing mechanism	22		22		—		—		22		22
Other	52		46		40		30		12		16
		$1,351		$1,424		$691		$715		$660		$709

Tax-related - Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities are primarily related to excess deferred tax benefits resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform. During the nine months ended September 30, 2020, Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities decreased primarily from returning a portion of these excess deferred tax benefits back to customers.

IPL’s DAEC PPA amendment - In September 2020, IPL made a buyout payment of $110 million in exchange for shortening the term of its DAEC PPA by 5 years. The payment was recorded as a reduction to “Other current liabilities” on Alliant Energy’s and IPL’s balance sheets and was included in “DAEC PPA amendment buyout payment” in Alliant Energy’s and IPL’s cash flows used for operating activities for the nine months ended September 30, 2020. The buyout payment will be recovered from IPL’s retail and wholesale customers beginning in the fourth quarter of 2020 through the end of 2025.

Electric transmission cost recovery - In the second quarter of 2020, pursuant to a June 2020 IUB order, IPL issued $42 million of credits to its retail electric customers through its transmission cost rider for amounts previously collected in rates, which resulted in a corresponding reduction to “Electric transmission service” expense in Alliant Energy’s and IPL’s income statements for the nine months ended September 30, 2020.

Refer to Note 13(f) for discussion of refunds received by IPL and WPL in 2020 related to MISO transmission owner return on equity complaints.

WPL’s West Riverside liquidated damages - Pursuant to terms included in the related West Riverside construction procurement contracts, WPL reached agreement with the contractor on liquidated damages in the third quarter of 2020. A significant portion of the liquidated damages was settled by WPL offsetting amounts owed to the contractor that were previously withheld for payment, which were non-cash investing activities. The liquidated damages are expected to be returned to WPL’s customers as determined in future regulatory proceedings.

August 2020 Derecho Windstorm - In August 2020, a derecho windstorm caused considerable damage to IPL’s electric distribution system in its service territory, and over 250,000 of its customers lost power. IPL completed its initial restoration and rebuilding efforts in August 2020 and expects permanent repairs to the system to continue throughout 2020. IPL’s current estimate of the total cost of the windstorm is approximately $140 million, and as of September 30, 2020, approximately $130 million was recorded substantially to “Property, plant and equipment, net” on Alliant Energy’s and IPL’s balance sheets. Tax benefits and the incremental operation and maintenance expenses resulting from the windstorm were deferred and recorded

13

as a net regulatory liability of $7 million as of September 30, 2020, which is included in “Other” regulatory liabilities in the above table. In November 2020, IPL filed a request with the IUB for utilization of a regulatory account to track certain incremental costs and benefits incurred resulting from the windstorm until IPL’s next rate proceeding.

NOTE 3. RECEIVABLES

Note 3(a) Accounts Receivable - Details for accounts receivable included on the balance sheets were as follows (in millions):

	Alliant Energy						IPL						WPL
	September 30, 2020			December 31, 2019			September 30, 2020			December 31, 2019			September 30, 2020			December 31, 2019
Customer		$95			$92			$—			$—			$86			$84
Unbilled utility revenues	62			82			—			—			62			82
Deferred proceeds	201			188			201			188			—			—
Other	54			47			20			16			33			31
Allowance for expected credit losses	(13		)	(7		)	(2		)	(1		)	(11		)	(6		)
		$399			$402			$219			$203			$170			$191

Note 3(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. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. As of September 30, 2020, IPL had $109 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 nine months ended September 30 were as follows (in millions):

	Three Months				Nine Months
	2020		2019		2020		2019
Maximum outstanding aggregate cash proceeds		$1		$103		$96		$108
Average outstanding aggregate cash proceeds	1		45		12		43

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

	September 30, 2020		December 31, 2019
Customer accounts receivable		$148		$125
Unbilled utility revenues	67		95
Other receivables	—		1
Receivables sold to third party	215		221
Less: cash proceeds	1		27
Deferred proceeds	214		194
Less: allowance for expected credit losses	13		6
Fair value of deferred proceeds		$201		$188

As of September 30, 2020, outstanding receivables past due under the Receivables Agreement were $27 million. Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and nine months ended September 30 were as follows (in millions):

	Three Months				Nine Months
	2020		2019		2020		2019
Collections		$561		$592		$1,555		$1,636
Write-offs, net of recoveries	1		3		4		11

NOTE 4. 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 nine months ended September 30 was as follows (in millions):

	Three Months						Nine Months
	2020			2019			2020			2019
ATC Holdings		($11	)		($11	)		($36	)		($30	)
Non-utility wind farm in Oklahoma	(2		)	—			(6		)	(3		)
Other	(2		)	(1		)	(4		)	(2		)
		($15	)		($12	)		($46	)		($35	)

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NOTE 5. COMMON EQUITY

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

Shares outstanding, January 1, 2020	245,022,800
Equity forward agreements	4,275,127
Shareowner Direct Plan	364,531
Equity-based compensation plans	98,205
Shares outstanding, September 30, 2020	249,760,663

Equity Forward Agreements - In November 2019, Alliant Energy entered into forward sale agreements with a counterparty in connection with a public offering of 4,275,127 shares of Alliant Energy common stock. The initial forward sale price of $52.235 per share was subject to daily adjustment based on a floating interest rate factor, and decreased by other fixed amounts specified in the forward sale agreements. In the first quarter of 2020, Alliant Energy settled $222 million under the forward sale agreements by delivering 4,275,127 shares of newly issued Alliant Energy common stock at a weighted average forward sale price of $51.98 per share. Alliant Energy used the net proceeds from the settlements for general corporate purposes.

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			Cumulative
			Additional					Other			Deferred			Preferred
	Common		Paid-In		Retained			Comprehensive			Compensation			Stock		Total
	Stock		Capital		Earnings			Income (Loss)			Trust			of IPL		Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$2		$2,683		$2,874			($1	)		($10	)		$200		$5,748
Net income attributable to Alliant Energy common shareowners					246											246
Common stock dividends ($0.38 per share)					(94		)									(94		)
Shareowner Direct Plan issuances			6													6
Equity-based compensation plans and other			4								(1		)			3
Ending balance, September 30, 2020		$2		$2,693		$3,026			($1	)		($11	)		$200		$5,909
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$2		$2,109		$2,598			$1			($10	)		$200		$4,900
Net income attributable to Alliant Energy common shareowners					226											226
Common stock dividends ($0.355 per share)					(85		)									(85		)
Equity forward settlements and Shareowner Direct Plan issuances			125													125
Equity-based compensation plans and other			3													3
Ending balance, September 30, 2019		$2		$2,237		$2,739			$1			($10	)		$200		$5,169

15

Alliant Energy	Total Alliant Energy Common Equity
								Accumulated			Shares in			Cumulative
			Additional					Other			Deferred			Preferred
	Common		Paid-In		Retained			Comprehensive			Compensation			Stock		Total
	Stock		Capital		Earnings			Income (Loss)			Trust			of IPL		Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$2		$2,446		$2,766			$1			($10	)		$200		$5,405
Net income attributable to Alliant Energy common shareowners					550											550
Common stock dividends ($1.14 per share)					(281		)									(281		)
Equity forward settlements and Shareowner Direct Plan issuances			241													241
Equity-based compensation plans and other			6								(1		)			5
Adoption of new accounting standard, net of tax (refer to Note 1(d))					(9		)									(9		)
Other comprehensive loss, net of tax								(2		)						(2		)
Ending balance, September 30, 2020		$2		$2,693		$3,026			($1	)		($11	)		$200		$5,909
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$2		$2,046		$2,546			$2			($10	)		$200		$4,786
Net income attributable to Alliant Energy common shareowners					446											446
Common stock dividends ($1.065 per share)					(253		)									(253		)
Equity forward settlements and Shareowner Direct Plan issuances			185													185
Equity-based compensation plans and other			6													6
Other comprehensive loss, net of tax								(1		)						(1		)
Ending balance, September 30, 2019		$2		$2,237		$2,739			$1			($10	)		$200		$5,169

IPL	Total IPL Common Equity
			Additional					Cumulative
	Common		Paid-In		Retained			Preferred		Total
	Stock		Capital		Earnings			Stock		Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$33		$2,523		$915			$200		$3,671
Net income available for common stock					148					148
Common stock dividends					(59		)			(59		)
Capital contributions from parent			170							170
Ending balance, September 30, 2020		$33		$2,693		$1,004			$200		$3,930
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$33		$2,323		$789			$200		$3,345
Net income available for common stock					141					141
Common stock dividends					(42		)			(42		)
Ending balance, September 30, 2019		$33		$2,323		$888			$200		$3,444

IPL	Total IPL Common Equity
			Additional					Cumulative
	Common		Paid-In		Retained			Preferred		Total
	Stock		Capital		Earnings			Stock		Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$33		$2,348		$891			$200		$3,472
Net income available for common stock					290					290
Common stock dividends					(177		)			(177		)
Capital contributions from parent			345							345
Ending balance, September 30, 2020		$33		$2,693		$1,004			$200		$3,930
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$33		$2,223		$775			$200		$3,231
Net income available for common stock					239					239
Common stock dividends					(126		)			(126		)
Capital contributions from parent			100							100
Ending balance, September 30, 2019		$33		$2,323		$888			$200		$3,444

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WPL			Additional					Total
	Common		Paid-In		Retained			Common
	Stock		Capital		Earnings			Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$66		$1,459		$927			$2,452
Net income					73			73
Common stock dividends					(43		)	(43		)
Ending balance, September 30, 2020		$66		$1,459		$957			$2,482
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$66		$1,309		$810			$2,185
Net income					76			76
Common stock dividends					(36		)	(36		)
Capital contributions from parent			100					100
Ending balance, September 30, 2019		$66		$1,409		$850			$2,325

WPL			Additional					Total
	Common		Paid-In		Retained			Common
	Stock		Capital		Earnings			Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$66		$1,434		$864			$2,364
Net income					220			220
Common stock dividends					(127		)	(127		)
Capital contributions from parent			25					25
Ending balance, September 30, 2020		$66		$1,459		$957			$2,482
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$66		$1,309		$775			$2,150
Net income					183			183
Common stock dividends					(108		)	(108		)
Capital contributions from parent			100					100
Ending balance, September 30, 2019		$66		$1,409		$850			$2,325

NOTE 6. DEBT

NOTE 6(a) Short-term Debt - Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, which currently expires in August 2023, classified as short-term debt was as follows (dollars in millions):

September 30, 2020	Alliant Energy	IPL	WPL
Amount outstanding	$422	$—	$139
Weighted average interest rates	0.2%	N/A	0.1%
Available credit facility capacity	$578	$250	$161

	Alliant Energy				IPL				WPL
Three Months Ended September 30	2020		2019		2020		2019		2020		2019
Maximum amount outstanding (based on daily outstanding balances)		$422		$472		$—		$—		$139		$90
Average amount outstanding (based on daily outstanding balances)		$252		$400		$—		$—		$83		$27
Weighted average interest rates	0.2%		2.5%		N/A		N/A		0.2%		2.3%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)		$463		$601		$8		$50		$212		$195
Average amount outstanding (based on daily outstanding balances)		$252		$476		$—		$—		$86		$102
Weighted average interest rates	1.1%		2.6%		0.5%		2.8%		1.2%		2.5%

NOTE 6(b) Long-term Debt - In March 2020, AEF entered into a $300 million variable rate (1% as of September 30, 2020) term loan credit agreement (with Alliant Energy as guarantor) and used the borrowings under this agreement to retire its $300 million variable rate term loan credit agreement that would have expired in April 2020. AEF’s current term loan credit agreement expires in March 2022 and includes substantially the same financial covenants that are included in Alliant Energy’s credit facility agreement.

17

In April 2020, WPL issued $350 million of 3.65% debentures due 2050. The net proceeds from the issuance were used by WPL to reduce borrowings under the single credit facility and for general corporate purposes. In June 2020, WPL retired its $150 million 4.6% debentures.

In June 2020, IPL issued $400 million of 2.3% senior debentures due 2030. The net proceeds from the issuance were used by IPL to retire its $200 million 3.65% senior debentures that would have matured in September 2020 and for general corporate purposes.

NOTE 7. 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 September 30	2020		2019		2020		2019		2020		2019
Electric Utility:
Retail - residential		$328		$332		$189		$196		$139		$136
Retail - commercial	210		231		142		158		68		73
Retail - industrial	241		264		149		158		92		106
Wholesale	47		50		17		18		30		32
Bulk power and other	26		39		22		31		4		8
Total Electric Utility	852		916		519		561		333		355
Gas Utility:
Retail - residential	22		20		12		12		10		8
Retail - commercial	10		10		6		6		4		4
Retail - industrial	2		3		1		2		1		1
Transportation/other	8		9		5		5		3		4
Total Gas Utility	42		42		24		25		18		17
Other Utility:
Steam	8		9		8		9		—		—
Other utility	2		2		2		2		—		—
Total Other Utility	10		11		10		11		—		—
Non-Utility and Other:
Transportation and other	16		21		—		—		—		—
Total Non-Utility and Other	16		21		—		—		—		—
Total revenues		$920		$990		$553		$597		$351		$372

	Alliant Energy				IPL				WPL
Nine Months Ended September 30	2020		2019		2020		2019		2020		2019
Electric Utility:
Retail - residential		$845		$840		$472		$470		$373		$370
Retail - commercial	556		583		371		386		185		197
Retail - industrial	648		686		384		392		264		294
Wholesale	127		137		44		49		83		88
Bulk power and other	81		104		61		76		20		28
Total Electric Utility	2,257		2,350		1,332		1,373		925		977
Gas Utility:
Retail - residential	146		187		79		109		67		78
Retail - commercial	70		90		38		50		32		40
Retail - industrial	8		10		5		7		3		3
Transportation/other	29		36		19		22		10		14
Total Gas Utility	253		323		141		188		112		135
Other Utility:
Steam	27		27		27		27		—		—
Other utility	5		6		4		5		1		1
Total Other Utility	32		33		31		32		1		1
Non-Utility and Other:
Transportation and other	57		62		—		—		—		—
Total Non-Utility and Other	57		62		—		—		—		—
Total revenues		$2,599		$2,768		$1,504		$1,593		$1,038		$1,113

18

NOTE 8. 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. The decreases in overall effective income tax rates for the three and nine months ended September 30, 2020 compared to the same periods in 2019 were primarily due to increases in production tax credits as a result of increased wind production in 2020 and increased amortization of excess deferred taxes primarily at WPL, which were used to offset increases in WPL’s 2020 increased revenue requirements.

	Alliant Energy				IPL				WPL
	Three Months		Nine Months		Three Months		Nine Months		Three Months		Nine Months
	2020	2019	2020	2019	2020	2019	2020	2019	2020	2019	2020	2019
Overall income tax rate	(9%)	9%	(9%)	10%	(14%)	5%	(14%)	4%	(7%)	18%	(8%)	18%

Deferred Tax Assets and Liabilities -

Carryforwards - At September 30, 2020, carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy		IPL		WPL
Federal net operating losses	2037		$371		$343		$3
State net operating losses	2020-2040	623		10		2
Federal tax credits	2022-2040	446		252		173

NOTE 9. BENEFIT PLANS

NOTE 9(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 nine months ended September 30 are included below (in millions). For IPL and WPL, amounts represent those 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						Nine Months						Three Months						Nine Months
Alliant Energy	2020			2019			2020			2019			2020			2019			2020			2019
Service cost		$3			$2			$8			$7			$1			$1			$3			$3
Interest cost	10			13			32			37			2			2			5			6
Expected return on plan assets	(17		)	(15		)	(52		)	(45		)	(1		)	(1		)	(4		)	(4		)
Amortization of actuarial loss	9			9			26			27			—			1			2			2
Settlement losses (a)	—			—			4			—			—			—			—			—
		$5			$9			$18			$26			$2			$3			$6			$7

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
IPL	2020			2019			2020			2019			2020			2019			2020			2019
Service cost		$2			$1			$5			$4			$—			$—			$1			$1
Interest cost	5			6			15			17			1			1			2			3
Expected return on plan assets	(8		)	(7		)	(24		)	(21		)	(1		)	(1		)	(3		)	(3		)
Amortization of actuarial loss	4			4			11			12			—			1			1			1
		$3			$4			$7			$12			$—			$1			$1			$2

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months					Nine Months
WPL	2020			2019			2020			2019			2020			2019		2020			2019
Service cost		$1			$1			$3			$3			$—			$—		$1			$1
Interest cost	5			5			14			16			1			1		2			3
Expected return on plan assets	(8		)	(6		)	(23		)	(20		)	(1		)	—		(1		)	(1		)
Amortization of actuarial loss	4			4			12			13			1			—		2			1
		$2			$4			$6			$12			$1			$1		$4			$4

(a) Settlement losses related to payments made to retired executives of Alliant Energy.

NOTE 9(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 nine months ended September 30 was as follows (in millions):

19

	Alliant Energy								IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months				Three Months				Nine Months
	2020		2019		2020		2019		2020		2019		2020		2019		2020		2019		2020		2019
Compensation expense		$5		$8		$10		$16		$3		$4		$6		$9		$2		$3		$4		$6
Income tax benefits	1		2		3		4		1		1		2		2		—		1		1		2

As of September 30, 2020, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $7 million, $4 million and $3 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years.

For the nine months ended September 30, 2020, performance shares, performance restricted stock units and restricted stock units were granted to key employees as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards. As of September 30, 2020, 276,070 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

		Weighted Average
	Grants	Grant Date Fair Value
Performance shares	55,303		$64.04
Performance restricted stock units	55,303	59.47
Restricted stock units	60,284	59.49

NOTE 10. ASSET RETIREMENT OBLIGATIONS

A reconciliation of the changes in asset retirement obligations associated with long-lived assets for the nine months ended September 30, 2020 is as follows (in millions):

	Alliant Energy			IPL
Balance, January 1		$196			$134
Revisions in estimated cash flows	1			—
Liabilities settled	(7		)	(5		)
Liabilities incurred (a)	38			38
Accretion expense	5			4
Balance, September 30		$233			$171

(a) During the nine months ended September 30, 2020, Alliant Energy and IPL recognized additional asset retirement obligations related to IPL’s newly constructed Whispering Willow North, Golden Plains and Richland wind sites. The increases in asset retirement obligations resulted in corresponding increases in property, plant and equipment, net on the respective balance sheets.

NOTE 11. DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Notional Amounts - As of September 30, 2020, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):

	FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	14,365	2020-2021	218,581	2020-2028	8,151	2020-2023	6,174	2020-2022
IPL	5,401	2020-2021	114,747	2020-2028	3,373	2020-2023	—	—
WPL	8,964	2020-2021	103,834	2020-2027	4,778	2020-2023	6,174	2020-2022

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
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Current derivative assets		$33		$16		$23		$12		$10		$4
Non-current derivative assets	15		11		11		10		4		1
Current derivative liabilities	6		19		2		9		4		10
Non-current derivative liabilities	13		19		6		9		7		10

20

Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At September 30, 2020 and December 31, 2019, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered.

Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at September 30, 2020 and December 31, 2019. Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement.

NOTE 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	September 30, 2020										December 31, 2019
			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		$183		$183		$—		$—		$183		$5		$5		$—		$—		$5
Derivatives	48		—		17		31		48		27		—		5		22		27
Deferred proceeds	201		—		—		201		201		188		—		—		188		188
Liabilities:
Derivatives	19		—		18		1		19		38		—		37		1		38
Long-term debt (incl. current maturities)	6,581		—		7,849		2		7,851		6,190		—		6,918		2		6,920

IPL	September 30, 2020										December 31, 2019
			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		$183		$183		$—		$—		$183		$5		$5		$—		$—		$5
Derivatives	34		—		7		27		34		22		—		3		19		22
Deferred proceeds	201		—		—		201		201		188		—		—		188		188
Liabilities:
Derivatives	8		—		7		1		8		18		—		17		1		18
Long-term debt (incl. current maturities)	3,344		—		3,987		—		3,987		3,147		—		3,489		—		3,489

WPL	September 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Derivatives		$14		$—		$10		$4		$14		$5		$—		$2		$3		$5
Liabilities:
Derivatives	11		—		11		—		11		20		—		20		—		20
Long-term debt (incl. current maturities)	2,130		—		2,667		—		2,667		1,933		—		2,268		—		2,268

21

Information for Alliant Energy’s and IPL’s fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions). Such amounts for WPL were not material.

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2020			2019			2020		2019
Beginning balance, July 1		$36			$13			$194		$215
Total net gains included in changes in net assets (realized/unrealized)	—			13			—		—
Transfers out of Level 3	—			(1		)	—		—
Sales	(1		)	—			—		—
Settlements (a)	(5		)	(3		)	7		22
Ending balance, September 30		$30			$22			$201		$237
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 September 30		($1	)		$13			$—		$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2020			2019			2020		2019
Beginning balance, January 1		$21			$12			$188		$119
Total net gains included in changes in net assets (realized/unrealized)	8			7			—		—
Transfers out of Level 3	—			3			—		—
Purchases	14			14			—		—
Sales	(1		)	—			—		—
Settlements (a)	(12		)	(14		)	13		118
Ending balance, September 30		$30			$22			$201		$237
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30		$8			$10			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2020			2019			2020		2019
Beginning balance, July 1		$32			$9			$194		$215
Total net gains (losses) included in changes in net assets (realized/unrealized)	(1		)	12			—		—
Transfers out of Level 3	—			(1		)	—		—
Sales	(1		)	—			—		—
Settlements (a)	(4		)	(2		)	7		22
Ending balance, September 30		$26			$18			$201		$237
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 September 30		($1	)		$12			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2020			2019			2020		2019
Beginning balance, January 1		$18			$9			$188		$119
Total net gains included in changes in net assets (realized/unrealized)	7			9			—		—
Transfers out of Level 3	—			2			—		—
Purchases	11			9			—		—
Sales	(1		)	—			—		—
Settlements (a)	(9		)	(11		)	13		118
Ending balance, September 30		$26			$18			$201		$237
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30		$7			$10			$—		$—

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

22

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

	Alliant Energy				IPL				WPL
	Excluding FTRs		FTRs		Excluding FTRs		FTRs		Excluding FTRs		FTRs
September 30, 2020		$18		$12		$17		$9		$1		$3
December 31, 2019	15		7		14		5		1		2

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. WPL’s projects include the expansion of solar and wind generation and its gas distribution system in Western Wisconsin. At September 30, 2020, Alliant Energy’s and WPL’s minimum future commitments for these projects were $21 million and $18 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 September 30, 2020, related minimum future commitments were as follows (in millions):

	Alliant Energy		IPL		WPL
Natural gas		$983		$508		$475
Coal (a)	125		70		55
Other (b)	111		49		31
		$1,219		$627		$561

(a) Corporate Services has historically entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. Such commitments were assigned to IPL and WPL based on information available as of September 30, 2020 regarding expected future usage, which is subject to change.

(b) Includes individual commitments incurred during the normal course of business that exceeded $1 million at September 30, 2020.

Refer to Note 2 for discussion of an amendment to shorten the term of the DAEC PPA, which resulted in IPL making a buyout payment in September 2020.

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 September 30, 2020, the currently known partnership obligations for the abandonment obligations are estimated at $68 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 $68 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, the new credit loss accounting standard adopted on January 1, 2020 requires recognition of a liability for expected credit losses related to the contingent obligations that are in the scope of these guarantees. With the adoption of this standard, Alliant Energy recorded a pre-tax $12 million cumulative effect adjustment to decrease the opening balance of retained earnings as of January 1, 2020.

Whiting Petroleum’s creditworthiness deteriorated in the first quarter of 2020, likely from significantly depressed oil and gas prices and general market conditions, and as a result, the credit loss liability was increased to $20 million in the first quarter of 2020. In April 2020, Whiting Petroleum filed for bankruptcy, and in September 2020, Whiting Petroleum completed its reorganization and emerged from bankruptcy. As a result of Whiting Petroleum’s completed bankruptcy proceedings, as well as additional information regarding the guarantees obtained from the bankruptcy proceedings, the credit loss liability was decreased to $5 million in the third quarter of 2020. The credit loss liability is recorded in “Other liabilities” on Alliant Energy’s balance sheet as of September 30, 2020. For the three and nine months ended September 30, 2020, the pre-tax credit loss adjustments of $15 million and $7 million, respectively, were recorded as reductions in Alliant Energy’s “Other operation and maintenance” expenses.

23

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 $74 million as of September 30, 2020 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 September 30, 2020 and December 31, 2019.

IPL’s Minnesota Electric Distribution Assets - IPL provided indemnifications associated with the 2015 sale of its Minnesota electric distribution assets for losses resulting from potential breach of IPL’s representations, warranties and obligations under the sale agreement. IPL has not recorded any material liabilities related to these indemnifications as of September 30, 2020 and December 31, 2019. The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expired in October 2020.

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 September 30, 2020, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At September 30, 2020, such amounts for WPL were not material.

	Alliant Energy				IPL
Range of estimated future costs		$12	-	$29		$9	-	$24
Current and non-current environmental liabilities	16				13

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 Burlington by December 31, 2021 and 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 to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: 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) Collective Bargaining Agreements - In August 2020, IPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 204 (Cedar Rapids) expired and a new agreement was reached, which expires August 31, 2024.

NOTE 13(f) MISO Transmission Owner Return on Equity Complaints - A group of MISO cooperative and municipal utilities previously filed complaints with FERC requesting a reduction to the base return on equity used by MISO transmission owners, including ITC Midwest LLC and ATC. The first complaint covered the period from November 12, 2013 through February 11, 2015. In 2017, IPL and WPL received refunds related to the first complaint period, which were subsequently refunded to their retail and wholesale customers. The second complaint covered the period from February 12, 2015 through May 11, 2016. In November 2019, FERC issued an order on the previously filed complaints and reduced the base return on equity used by the MISO transmission owners to 9.88% effective for the first complaint period and subsequent to September 28, 2016. The November 2019 FERC order also dismissed the second complaint; therefore, FERC did not direct refunds to be made for that complaint. In May 2020, FERC issued an order in response to various rehearing requests and increased the base return on equity used by the MISO transmission owners from 9.88% to 10.02% for the first complaint period and subsequent to September 28, 2016, which reduces the refunds originally anticipated to be received by IPL and WPL as a result of FERC’s November 2019 order.

For the nine months ended September 30, 2020, IPL and WPL received $15 million and $5 million, respectively, in refunds related to the FERC orders. In October 2020, FERC extended the time to complete additional refunds to September 2021.

24

IPL currently expects that all refunds will be returned to its retail electric customers after refund amounts and timing are known and a refund plan is approved by the IUB. WPL proposed to retain the refunds as part of WPL’s application with the PSCW to maintain its current retail electric base rates through the end of 2021. WPL currently expects that any refunds not utilized to maintain base rates would be returned to its customers in WPL’s next retail electric rate review proceeding. 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 September 30, 2020
Revenues		$852		$42			$10		$904		$16		$920
Operating income (loss)	251		(1		)	1		251		21		272
Net income attributable to Alliant Energy common shareowners								221		25		246
Three Months Ended September 30, 2019
Revenues		$916		$42			$11		$969		$21		$990
Operating income (loss)	284		(5		)	3		282		8		290
Net income attributable to Alliant Energy common shareowners								217		9		226

Alliant Energy									ATC Holdings,		Alliant
	Utility								Non-Utility,		Energy
	Electric		Gas		Other		Total		Parent and Other		Consolidated
	(in millions)
Nine Months Ended September 30, 2020
Revenues		$2,257		$253		$32		$2,542		$57		$2,599
Operating income	549		48		5		602		26		628
Net income attributable to Alliant Energy common shareowners							510		40		550
Nine Months Ended September 30, 2019
Revenues		$2,350		$323		$33		$2,706		$62		$2,768
Operating income	543		47		5		595		22		617
Net income attributable to Alliant Energy common shareowners							422		24		446

IPL	Electric		Gas			Other		Total
	(in millions)
Three Months Ended September 30, 2020
Revenues		$519		$24			$10		$553
Operating income	159		1			2		162
Net income available for common stock								148
Three Months Ended September 30, 2019
Revenues		$561		$25			$11		$597
Operating income (loss)	175		(4		)	3		174
Net income available for common stock								141
Nine Months Ended September 30, 2020
Revenues		$1,332		$141			$31		$1,504
Operating income	308		34			5		347
Net income available for common stock								290
Nine Months Ended September 30, 2019
Revenues		$1,373		$188			$32		$1,593
Operating income	291		26			5		322
Net income available for common stock								239

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WPL	Electric		Gas			Other			Total
	(in millions)
Three Months Ended September 30, 2020
Revenues		$333		$18			$—			$351
Operating income (loss)	92		(2		)	(1		)	89
Net income									73
Three Months Ended September 30, 2019
Revenues		$355		$17			$—			$372
Operating income (loss)	109		(1		)	—			108
Net income									76
Nine Months Ended September 30, 2020
Revenues		$925		$112			$1			$1,038
Operating income	241		14			—			255
Net income									220
Nine Months Ended September 30, 2019
Revenues		$977		$135			$1			$1,113
Operating income	252		21			—			273
Net income									183

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 nine months ended September 30 were as follows (in millions):

	IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months
	2020		2019		2020		2019		2020		2019		2020		2019
Corporate Services billings		$53		$47		$134		$137		$41		$36		$108		$104
Sales credited	10		23		35		50		—		2		4		6
Purchases billed	110		93		248		251		39		32		79		91

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

	IPL		WPL
	September 30, 2020	December 31, 2019	September 30, 2020	December 31, 2019
Net payables to Corporate Services	$119	$112	$77	$85

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 nine months ended September 30 were as follows (in millions):

	Three Months				Nine Months
	2020		2019		2020		2019
ATC billings to WPL		$27		$28		$80		$82
WPL billings to ATC	2		3		8		10

WPL owed ATC net amounts of $9 million as of September 30, 2020 and $9 million as of December 31, 2019. In the second quarter of 2020, WPL received $46 million from ATC related to construction deposits WPL previously provided ATC for transmission network upgrades for West Riverside, which is substantially recorded in “Other” in Alliant Energy’s and WPL’s cash flows from investing activities.

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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 2019 Form 10-K. Unless otherwise noted, all “per share” references in MDA refer to earnings per diluted share.

2020 HIGHLIGHTS

Key highlights since the filing of the 2019 Form 10-K include the following:

COVID-19:

The outbreak of COVID-19 has become a global pandemic and Alliant Energy’s service territories are not immune to the challenges presented by COVID-19. Despite these challenges, Alliant Energy, IPL and WPL continue to focus on providing the critical, reliable service their customers depend on, while emphasizing the health and welfare of their employees, customers and communities. Alliant Energy, IPL and WPL have not experienced significant impacts on their overall business operations, financial condition, results of operations or cash flows for the three and nine months ended September 30, 2020; however, the degree to which the COVID-19 pandemic may impact such items in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities. Alliant Energy has mitigated the impact of sales declines from COVID-19 by accelerating planned cost transformation activities. Actual and potential impacts from COVID-19 include, but are not limited to, the following:

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

While Alliant Energy has not experienced any significant issues to-date, it continues to monitor potential disruptions or constraints in materials and supplies from key suppliers. In addition, Alliant Energy’s construction projects are currently progressing as planned with added safety protocols, and while it continues to monitor its supply chain, there have been no immediate disruptions. Alliant Energy’s wind farms under construction during the pandemic were placed in service as previously planned to meet the timing requirements to qualify for the maximum renewable tax credits. In addition, Alliant Energy does not currently expect any material changes to its construction and acquisition expenditures plans disclosed in “Liquidity and Capital Resources” resulting from COVID-19.

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

Customer Impacts - COVID-19 has resulted in various travel restrictions and closures of commercial spaces and industrial facilities in Alliant Energy’s service territories. While the total expected impact of COVID-19 on future sales is currently unknown, Alliant Energy has experienced higher electric residential sales and lower electric commercial and industrial sales since the outset of the pandemic. For the nine months ended September 30, 2020 compared to the same period in 2019, Alliant Energy’s retail electric residential temperature-normalized sales increased 3%, and its retail electric commercial and industrial temperature-normalized sales decreased 4% in aggregate. While sales to retail electric commercial and industrial customers have largely recovered to pre-COVID-19 levels in the third quarter of 2020, given the continued uncertainty of COVID-19 impacts on sales, Alliant Energy currently expects a slight reduction in temperature-normalized retail sales in 2020 compared to 2019. From a sensitivity perspective, Alliant Energy currently estimates that an annual 1% increase/decrease in sales for each customer type would result in corresponding annual impacts of $0.02 EPS for its retail electric residential customers, $0.01 EPS for its retail electric commercial customers and $0.01 EPS for its retail electric industrial customers.

Liquidity and Capital Resources Impacts - In response to the uncertainty of the impacts of COVID-19, Alliant Energy enhanced its liquidity position in the first quarter of 2020 by settling $222 million under the equity forward sale agreements and AEF accelerating the refinancing of its $300 million term-loan credit agreement that would have been due in April 2020. In March 2020 and April 2020, Alliant Energy and WPL borrowed under the single credit facility for a portion of their cash needs to obtain more favorable interest rates than available in the commercial paper market. This single credit facility also allows borrowing capacity to shift among Alliant Energy (at the parent company level), IPL and WPL as needed. In April 2020, WPL issued $350 million of debentures due 2050, and in June 2020, IPL issued $400 million of senior debentures due 2030. In June 2020, IPL and WPL retired $200 million and $150 million of long-term debt, respectively, and there are no other material long-term debt maturities in 2020 and 2021. In addition, IPL maintains a sales of accounts receivable program as an alternative financing source; however, if customer arrears were to exceed certain levels, IPL’s access to the program may be restricted.

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Alliant Energy, IPL and WPL currently expect to maintain compliance with the financial covenants of the credit facility agreement, and Alliant Energy currently expects to maintain compliance with the financial covenants in AEF’s term loan credit agreement. In addition, Alliant Energy currently expects to have adequate liquidity to fulfill its contractual obligations, access to capital markets and continue with its planned quarterly dividend payments.

Credit Risk Impacts - Alliant Energy’s temporary suspension of service disconnects and waivers of late payment fees for its customers, as well as broad economic factors, may negatively impact its customers’ willingness and ability to pay, which could increase customer arrears and bad debts, and negatively impact Alliant Energy’s cash flows from operations. Currently, Alliant Energy does not anticipate any material credit risk related to its commodity transactions.

Regulatory Impacts - In March 2020, WPL received authorization from the PSCW to defer certain incremental costs incurred resulting from COVID-19, including bad debt expenses and foregone revenues from late payment fees and deposits. In June 2020, IPL filed a proposal with the IUB for utilization of a regulatory asset account to track increased expenses and other financial impacts incurred after March 1, 2020 resulting from COVID-19. The recovery of any authorized deferrals will be addressed in future regulatory proceedings. For the three and nine months ended September 30, 2020, such recorded amounts were not material.

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

August 2020 Derecho Windstorm:

In August 2020, a derecho windstorm caused considerable damage to IPL’s electric distribution system in its service territory, and over 250,000 of its customers lost power. IPL completed its initial restoration efforts in August 2020 and expects permanent repairs to the system to continue throughout 2020. Refer to Note 2 for further discussion, including IPL’s current estimate and requested regulatory treatment of certain incremental costs and benefits incurred resulting from the windstorm.

Rate Matters:

• Final retail electric rates for IPL’s 2020 Forward-looking Test Period rate review were effective February 26, 2020. Effective with the implementation of final rates, IPL started to recover a return of and return on its new wind generation placed in service in 2019 and 2020 through the renewable energy rider. IPL currently expects to file a subsequent proceeding with the IUB in the first half of 2021 for its 2020 Forward-looking Test Period retail electric and gas rate reviews, which will compare actual revenues and costs to those initially forecasted by IPL. IPL currently does not expect any rate adjustments from the subsequent proceeding.

• In August 2020, the PSCW issued an oral decision authorizing WPL to maintain its current retail electric and gas base rates, authorized return on common equity, regulatory capital structure and earnings sharing mechanism through the end of 2021. WPL will utilize anticipated fuel-related cost savings in 2021 to offset the revenue requirement impacts of the Kossuth wind farm, which was placed in service in October 2020. In addition, WPL will utilize excess deferred tax benefits to partially offset the revenue requirement of the expansion of its gas distribution system in Western Wisconsin, which is expected to be placed in service in late 2020. A written order from the PSCW is currently expected in the fourth quarter of 2020.

• In the second quarter of 2020, pursuant to a June 2020 IUB order, IPL issued $42 million of credits to its retail electric customers through its transmission cost rider for amounts previously collected in rates.

• In September 2020, pursuant to an August 2020 PSCW order, WPL refunded $12 million of 2019 fuel-related cost over-collections to its retail electric customers.

• In September 2020, IPL made a buyout payment of $110 million in exchange for shortening the term of its DAEC PPA by 5 years. Pursuant to IUB and FERC orders, the buyout payment will be recovered from IPL’s retail and wholesale customers beginning in the fourth quarter of 2020 and through the end of 2025.

• Beginning in the third quarter of 2020, IPL began providing retail electric billing credits that will continue through June 2021, which in aggregate include $27 million of excess deferred tax benefits and $8 million from a partial refund of interim rates implemented in 2019.

• WPL currently expects to file a retail electric and gas rate review with the PSCW in the second quarter of 2021 for either a single or multiple year forward-looking test period.

Customer Investments:

• In March 2020, IPL completed the construction of the Golden Plains wind farm in Iowa (200 MW).

• In April 2020, WPL received authorization from the PSCW to expand its gas distribution system in Western Wisconsin, which is currently expected to be completed in 2020.

• In May 2020, WPL completed the construction of the natural gas-fired West Riverside Energy Center (730 MW).

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• In May 2020, WPL filed a Certificate of Authority with the PSCW for approval to acquire, construct, own, and operate up to 675 MW of new solar generation in the following Wisconsin counties: Grant (200 MW in 2023), Sheboygan (150 MW in 2022), Wood (150 MW in 2022), Jefferson (75 MW in 2022), Richland (50 MW in 2022) and Rock (50 MW in 2023). The 675 MW of new solar generation would replace energy and capacity being eliminated with the planned retirement of the coal-fired Edgewater Generating Station (414 MW) by the end of 2022, which is subject to change depending on operational, regulatory, market and other factors. In addition, WPL currently expects to file a second Certificate of Authority with the PSCW in the first half of 2021 for approximately 325 MW of new solar generation. Estimated capital expenditures for these planned projects for 2020 through 2024 are included in the “Renewable projects” line in the construction and acquisition table in “Liquidity and Capital Resources.” WPL currently assumes that a portion of the construction costs will be financed by a tax equity partner, which is discussed in “IPL and WPL Solar Project Tax Equity Credits” in “Liquidity and Capital Resources.”

• In July 2020, Alliant Energy announced updated voluntary environmental-related goals based on its clean energy strategy. By 2030, Alliant Energy expects to reduce carbon dioxide emissions by 50% and water supply by 75% from 2005 levels from its owned fossil-fueled generation. By 2040, Alliant Energy expects to eliminate all coal-fired EGUs from its generating fleet, and by 2050, seeks to achieve an aspirational goal of net-zero carbon dioxide emissions from the electricity it generates. Future updates to sustainable energy plans and attaining these goals will depend on future economic developments, evolving energy technologies and emerging trends in Alliant Energy’s service territories.

• In September 2020, IPL completed the construction of the Richland wind farm in Iowa (130 MW).

• In October 2020, WPL completed the construction of the Kossuth wind farm in Iowa (150 MW).

• Alliant Energy’s cleaner energy strategy includes IPL’s planned development and acquisition of up to 400 MW of solar generation by the end of 2023 and up to 100 MW of distributed energy resources, including community solar and energy storage systems beginning in 2022. IPL currently plans to file for advance rate-making principles for the up to 400 MW of solar generation in the first half of 2021. Estimated capital expenditures for these planned projects for 2020 through 2024 are included in the “Renewable projects” line in the construction and acquisition table in “Liquidity and Capital Resources.” IPL currently assumes that a portion of the construction costs for the new solar generation will be financed by a tax equity partner, which is discussed in “IPL and WPL Solar Project Tax Equity Credits” in “Liquidity and Capital Resources.” The 400 MW of new solar generation would help replace a portion of the energy and capacity expected to be eliminated with the planned retirement of the coal-fired Lansing Generating Station (275 MW) by the end of 2022 and the expected reduction of energy and capacity resulting from the planned fuel switch of the Burlington Generating Station (212 MW) from coal to natural gas by the end of 2021. Both the Lansing Generating Station planned retirement and the planned fuel switch of the Burlington Generating Station are subject to change depending on operational, regulatory, market and other factors.

Financings and Common Stock Dividends:

• In March 2020, Alliant Energy settled $222 million under the equity forward sale agreements by delivering 4,275,127 shares of newly issued Alliant Energy common stock at a weighted average forward sale price of $51.98 per share.

• In March 2020, AEF entered into a $300 million variable rate (1% as of September 30, 2020) term loan credit agreement (with Alliant Energy as guarantor), which expires in March 2022, and used the borrowings under this agreement to retire its $300 million variable rate term loan credit agreement that would have expired in April 2020.

• In April 2020, WPL issued $350 million of 3.65% debentures due 2050. The net proceeds from the issuance were used by WPL to reduce borrowings under the single credit facility, which currently expires in August 2023, and for general corporate purposes. In June 2020, WPL retired its $150 million 4.6% debentures.

• In June 2020, IPL issued $400 million of 2.3% senior debentures due 2030. The net proceeds from the issuance were used by IPL to retire its $200 million 3.65% senior debentures that would have matured in September 2020 and for general corporate purposes.

• Refer to “Results of Operations” for discussion of expected issuances of common stock dividends and long-term debt in 2021.

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.

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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 September 30 were as follows (dollars in millions, except per share amounts):

	2020				2019
	Income		EPS		Income (Loss)			EPS
Utilities and Corporate Services		$224		$0.89		$220			$0.92
ATC Holdings	8		0.03		8			0.03
Non-utility and Parent	14		0.06		(2		)	(0.01		)
Alliant Energy Consolidated		$246		$0.98		$226			$0.94

Alliant Energy’s Utilities and Corporate Services net income increased by $4 million for the three-month period, primarily due to higher earnings resulting from IPL’s and WPL’s increasing rate base and timing of income taxes. These items were partially offset by higher depreciation expense and lower sales due to the derecho windstorm in Iowa.

Alliant Energy’s Non-utility and Parent net income increased by $16 million for the three-month period primarily due to an adjustment to the credit loss liability related to legacy guarantees associated with an affiliate of Whiting Petroleum and timing of income taxes.

For the three and nine months ended September 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	2020			2019			2020			2019			2020			2019
Operating income		$272			$290			$162			$174			$89			$108
Electric utility revenues		$852			$916			$519			$561			$333			$355
Electric production fuel and purchased power expenses	(179		)	(219		)	(102		)	(127		)	(78		)	(92		)
Electric transmission service expense	(132		)	(127		)	(93		)	(92		)	(39		)	(36		)
Utility Electric Margin (non-GAAP)	541			570			324			342			216			227
Gas utility revenues	42			42			24			25			18			17
Cost of gas sold	(11		)	(9		)	(6		)	(6		)	(4		)	(3		)
Utility Gas Margin (non-GAAP)	31			33			18			19			14			14
Other utility revenues	10			11			10			11			—			—
Non-utility revenues	16			21			—			—			—			—
Other operation and maintenance expenses	(143		)	(174		)	(85		)	(100		)	(65		)	(62		)
Depreciation and amortization expenses	(156		)	(144		)	(89		)	(84		)	(65		)	(59		)
Taxes other than income tax expense	(27		)	(27		)	(16		)	(14		)	(11		)	(12		)
Operating income		$272			$290			$162			$174			$89			$108

	Alliant Energy						IPL						WPL
Nine Months	2020			2019			2020			2019			2020			2019
Operating income		$628			$617			$347			$322			$255			$273
Electric utility revenues		$2,257			$2,350			$1,332			$1,373			$925			$977
Electric production fuel and purchased power expenses	(527		)	(602		)	(304		)	(339		)	(223		)	(263		)
Electric transmission service expense	(326		)	(363		)	(212		)	(257		)	(114		)	(106		)
Utility Electric Margin (non-GAAP)	1,404			1,385			816			777			588			608
Gas utility revenues	253			323			141			188			112			135
Cost of gas sold	(117		)	(151		)	(63		)	(80		)	(53		)	(71		)
Utility Gas Margin (non-GAAP)	136			172			78			108			59			64
Other utility revenues	32			33			31			32			1			1
Non-utility revenues	57			62			—			—			—			—
Other operation and maintenance expenses	(465		)	(527		)	(269		)	(306		)	(172		)	(188		)
Depreciation and amortization expenses	(454		)	(424		)	(264		)	(243		)	(186		)	(177		)
Taxes other than income tax expense	(82		)	(84		)	(45		)	(46		)	(35		)	(35		)
Operating income		$628			$617			$347			$322			$255			$273

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Operating Income Variances - Variances between periods in operating income for the three and nine months ended September 30, 2020 compared to the same periods in 2019 were as follows (in millions):

	Three Months									Nine Months
	Alliant Energy			IPL			WPL			Alliant Energy			IPL			WPL
Total higher (lower) utility electric margin variance (Refer to details below)		($29	)		($18	)		($11	)		$19			$39			($20	)
Total lower utility gas margin variance (Refer to details below)	(2		)	(1		)	—			(36		)	(30		)	(5		)
Total lower (higher) other operation and maintenance expenses variance (Refer to details below)	31			15			(3		)	62			37			16
Higher depreciation and amortization expense primarily due to additional plant in service in 2019 and 2020, including IPL’s new wind generation and WPL’s West Riverside Energy Center	(12		)	(5		)	(6		)	(30		)	(21		)	(9		)
Other	(6		)	(3		)	1			(4		)	—			—
		($18	)		($12	)		($19	)		$11			$25			($18	)

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

Alliant Energy	Electric						Gas
	Revenues				MWhs Sold		Revenues				Dths Sold
	2020		2019		2020	2019	2020		2019		2020	2019
Three Months
Retail		$779		$827	6,762	6,868		$34		$33	3,500	3,144
Sales for resale	54		72		1,453	2,003	N/A		N/A		N/A	N/A
Transportation/Other	19		17		17	23	8		9		24,842	25,021
		$852		$916	8,232	8,894		$42		$42	28,342	28,165
Nine Months
Retail		$2,049		$2,109	18,496	19,035		$224		$287	32,545	36,560
Sales for resale	162		190		4,962	4,835	N/A		N/A		N/A	N/A
Transportation/Other	46		51		53	71	29		36		79,546	71,814
		$2,257		$2,350	23,511	23,941		$253		$323	112,091	108,374

IPL	Electric						Gas
	Revenues				MWhs Sold		Revenues				Dths Sold
	2020		2019		2020	2019	2020		2019		2020	2019
Three Months
Retail		$480		$512	3,743	3,827		$19		$20	1,873	1,644
Sales for resale	25		38		765	1,414	N/A		N/A		N/A	N/A
Transportation/Other	14		11		9	9	5		5		9,020	8,701
		$519		$561	4,517	5,250		$24		$25	10,893	10,345
Nine Months
Retail		$1,227		$1,248	10,414	10,706		$122		$166	16,950	19,010
Sales for resale	75		95		3,090	3,241	N/A		N/A		N/A	N/A
Transportation/Other	30		30		27	27	19		22		29,127	28,528
		$1,332		$1,373	13,531	13,974		$141		$188	46,077	47,538

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WPL	Electric						Gas
	Revenues				MWhs Sold		Revenues				Dths Sold
	2020		2019		2020	2019	2020		2019		2020	2019
Three Months
Retail		$299		$315	3,019	3,041		$15		$13	1,627	1,500
Sales for resale	29		34		688	589	N/A		N/A		N/A	N/A
Transportation/Other	5		6		8	14	3		4		15,822	16,320
		$333		$355	3,715	3,644		$18		$17	17,449	17,820
Nine Months
Retail		$822		$861	8,082	8,329		$102		$121	15,595	17,550
Sales for resale	87		95		1,872	1,594	N/A		N/A		N/A	N/A
Transportation/Other	16		21		26	44	10		14		50,419	43,286
		$925		$977	9,980	9,967		$112		$135	66,014	60,836

Sales Trends and Temperatures - Alliant Energy’s retail electric sales volumes decreased 2% for the three months ended September 30, 2020 compared to the same period in 2019 primarily due to the impacts from the derecho windstorm in IPL’s service territory. Alliant Energy’s retail electric and gas sales volumes decreased 3% and 11% for the nine months ended September 30, 2020 compared to the same period in 2019, respectively, primarily due to the impacts from COVID-19, the derecho windstorm, and changes in temperatures in Alliant Energy’s service territories. The nine-month decrease in sales was partially offset by an extra day of sales during the first quarter of 2020 due to leap year. For the nine months ended September 30, 2020, COVID-19 impacts on sales volumes resulted in increases for retail electric residential sales volumes and decreases for retail electric commercial and industrial sales.

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

	Electric Margins														Gas Margins
	Three Months							Nine Months							Three Months						Nine Months
	2020		2019		Change			2020		2019		Change			2020		2019		Change		2020			2019		Change
IPL		$3		$4		($1	)		$2		$7		($5	)		$—		$—		$—		$—			$4		($4	)
WPL	3		2		1			3		2		1			—		—		—		(1		)	2		(3		)
Total Alliant Energy		$6		$6		$—			$5		$9		($4	)		$—		$—		$—		($1	)		$6		($7	)

Utility Electric Margin Variances - The following items contributed to increased (decreased) utility electric margins for the three and nine months ended September 30, 2020 compared to the same periods in 2019 as follows (in millions):

	Three Months									Nine Months
	Alliant Energy			IPL			WPL			Alliant Energy			IPL			WPL
Impact of IPL’s retail electric final and interim rate increases effective February 2020 and April 2019, respectively (a)		$7			$7			$—			$54			$54			$—
Higher revenues at IPL due to credits on customers’ bills in 2019 related to production tax credits through the fuel-related cost recovery mechanism (offset by changes in income tax)	3			3			—			13			13			—
Higher revenues at IPL due to changes in electric tax benefit rider credits on customers’ bills (offset by changes in income tax)	—			—			—			6			6			—
Higher WPL electric fuel-related costs, net of recoveries	(12		)	—			(12		)	(12		)	—			(12		)
Changes in timing of collection of electric transmission service costs at WPL	(3		)	—			(3		)	(8		)	—			(8		)
Lower revenues at IPL due to credits on customers’ bills in 2020 related to excess deferred amortization through the tax benefit rider (offset by changes in income tax)	(8		)	(8		)	—			(8		)	(8		)	—
Lower revenues at IPL related to changes in recovery amounts for energy efficiency costs through the energy efficiency rider (mostly offset by changes in energy efficiency expense)	(5		)	(5		)	—			(4		)	(4		)	—
Estimated changes in sales volumes caused by temperatures	—			(1		)	1			(4		)	(5		)	1
Other (includes lower temperature-normalized sales primarily due to the derecho windstorm and COVID-19 impacts)	(11		)	(14		)	3			(18		)	(17		)	(1		)
		($29	)		($18	)		($11	)		$19			$39			($20	)

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(a) IPL’s interim retail electric base rate increase was effective April 1, 2019 and final retail electric base rate increase was effective February 26, 2020. Effective with final rates, the recovery of, and return on, IPL’s new wind generation placed in service in 2019 and 2020 is provided through the renewable energy rider. Both interim and final rate increases include a reduction for anticipated production tax credits for IPL’s new wind generation. This reduction is expected to be offset by a reduction in income tax expense resulting from production tax credits recognized from this new wind generation.

Utility Gas Margin Variances - The following items contributed to increased (decreased) utility gas margins for the three and nine months ended September 30, 2020 compared to the same periods in 2019 as follows (in millions):

	Three Months								Nine Months
	Alliant Energy			IPL			WPL		Alliant Energy			IPL			WPL
Lower revenues at IPL related to changes in recovery amounts for energy efficiency costs through the energy efficiency rider (mostly offset by changes in energy efficiency expense)		($2	)		($2	)		$—		($29	)		($29	)		$—
Estimated changes in sales volumes caused by temperatures	—			—			—		(7		)	(4		)	(3		)
Impact of IPL’s retail gas rate increase effective January 2020	1			1			—		8			8			—
Other (includes lower temperature-normalized sales primarily due to COVID-19 impacts)	(1		)	—			—		(8		)	(5		)	(2		)
		($2	)		($1	)		$—		($36	)		($30	)		($5	)

Other Operation and Maintenance Expenses Variances - The following items contributed to (increased) decreased other operation and maintenance expenses for the three and nine months ended September 30, 2020 compared to the same periods in 2019 as follows (in millions):

	Three Months							Nine Months
	Alliant Energy		IPL		WPL			Alliant Energy		IPL		WPL
Lower energy efficiency expense at IPL (primarily offset by lower gas revenues)		$6		$6		$—			$32		$32		$—
Lower generation operation and maintenance expenses	3		3		—			12		5		7
Credit loss adjustments related to guarantees for an affiliate of Whiting Petroleum (Refer to Note 13(c))	15		—		—			7		—		—
Other	7		6		(3		)	11		—		9
		$31		$15		($3	)		$62		$37		$16

Other Income and Deductions Variances - The following items contributed to (increased) decreased other income and deductions for the three and nine months ended September 30, 2020 compared to the same periods in 2019 as follows (in millions):

	Three Months									Nine Months
	Alliant Energy			IPL			WPL			Alliant Energy			IPL			WPL
Higher interest expense primarily due to higher average outstanding long-term debt balances		$—			($3	)		($1	)		($3	)		($11	)		($1	)
Lower allowance for funds used during construction primarily due to changes in construction work in progress balances related to IPL’s new wind generation and WPL’s West Riverside Energy Center and new wind generation	(9		)	(5		)	(5		)	(15		)	(13		)	(2		)
Other (Refer to Note 4 for details of increased income from unconsolidated equity investments)	4			1			—			15			2			1
		($5	)		($7	)		($6	)		($3	)		($22	)		($2	)

Income Taxes - Alliant Energy’s overall effective income tax rates were (9)% and 9% for the three months ended September 30, 2020 and 2019, and (9)% and 10% for the nine months ended September 30, 2020 and 2019, respectively. The decrease in effective income tax rates is primarily due to increases in production tax credits as a result of increased wind production in 2020 and increases of amortization of excess deferred taxes primarily at WPL. WPL’s 2020 increased revenue requirements are offset by returning to customers a portion of the excess deferred income tax credits from Federal Tax Reform. Excess deferred income taxes and production tax credits are recognized based on an estimated annual effective tax rate, which contributed to a positive earnings variance during the nine months ended September 30, 2020. This positive earnings variance is expected to reverse by the end of 2020.

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Other Future Considerations - In addition to items discussed in MDA and the Notes in Item 1, the following key items could impact Alliant Energy’s, IPL’s and WPL’s future financial condition or results of operations:

• Financing Plans - WPL and AEF each currently expect to issue up to $300 million of long-term debt by the end of 2021.

• Common Stock Dividends - Alliant Energy announced a 6% increase in its targeted 2021 annual common stock dividend to $1.61 per share, which is equivalent to a quarterly rate of $0.4025 per share, beginning with the February 2021 dividend payment. The timing and amount of future dividends is subject to an approved dividend declaration from Alliant Energy’s Board of Directors, and is dependent upon earnings expectations, capital requirements, and general financial business conditions, among other factors.

• Higher Earnings on Increasing Rate Base - Alliant Energy, IPL and WPL currently expect an increase in earnings in 2021 compared to 2020 due to impacts from increasing revenue requirements related to investments in the utility business, including IPL’s and WPL’s wind investments, WPL’s Western Wisconsin gas distribution system expansion, and the impacts of IPL’s DAEC PPA amendment buyout payment.

• Depreciation and Amortization Expenses - Alliant Energy, IPL and WPL currently expect an increase in depreciation and amortization expenses in 2021 compared to 2020 due to property additions, including IPL’s and WPL’s expansion of wind generation and WPL’s natural gas-fired West Riverside Energy Center.

• Allowance for Funds Used During Construction - Alliant Energy currently expects allowance for funds used during construction to decrease in 2021 compared to 2020 primarily due to decreased construction work in progress balances related to IPL’s and WPL’s wind generation and WPL’s West Riverside Energy Center, which were placed in service in 2020.

LIQUIDITY AND CAPITAL RESOURCES

The liquidity and capital resources summary included in the 2019 Form 10-K has not changed materially, except as described below.

COVID-19 and Derecho Windstorm Considerations - Refer to “2020 Highlights” for discussion of COVID-19 and the derecho windstorm and the current and expected impacts on Alliant Energy’s, IPL’s and WPL’s liquidity and capital resources.

Liquidity Position - At September 30, 2020, Alliant Energy had $189 million of cash and cash equivalents, $578 million ($167 million at the parent company, $250 million at IPL and $161 million at WPL) of available capacity under the single revolving credit facility and $109 million of available capacity at IPL under its sales of accounts receivable program.

Capital Structure - Capital structures at September 30, 2020 were as follows (Long-term Debt (including current maturities) (LD); Short-term Debt (SD); Common Equity (CE); IPL’s Preferred Stock (PS)):

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

	Alliant Energy						IPL						WPL
	2020			2019			2020			2019			2020			2019
Cash, cash equivalents and restricted cash, January 1		$18			$26			$9			$12			$4			$9
Cash flows from (used for):
Operating activities	436			509			19			139			402			360
Investing activities	(679		)	(861		)	(202		)	(484		)	(465		)	(335		)
Financing activities	419			526			359			518			61			(24		)
Net increase (decrease)	176			174			176			173			(2		)	1
Cash, cash equivalents and restricted cash, September 30		$194			$200			$185			$185			$2			$10

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Operating Activities - The following items contributed to increased (decreased) operating activity cash flows for the nine months ended September 30, 2020 compared to the same period in 2019 (in millions):

	Alliant Energy			IPL			WPL
DAEC PPA amendment buyout payment in 2020 (Refer to Note 2)		($110	)		($110	)		$—
Amounts issued to IPL’s retail electric customers in 2020 through its transmission cost rider for amounts previously collected in rates (Refer to Note 2)	(42		)	(42		)	—
Decreased collections from IPL’s and WPL’s retail customers caused by temperature impacts on electric and gas sales	(11		)	(9		)	(2		)
Changes in interest payments	(2		)	(15		)	3
Higher collections from IPL’s retail electric and gas base rate increases	62			62			—
Changes in levels of production fuel	24			(3		)	27
Refunds received in 2020 related to the MISO transmission owner return on equity complaint FERC orders (Refer to Note 13(f))	20			15			5
Changes in income taxes paid/refunded	5			(20		)	12
Other (primarily due to other changes in working capital)	(19		)	2			(3		)
		($73	)		($120	)		$42

Investing Activities - The following items contributed to increased (decreased) investing activity cash flows for the nine months ended September 30, 2020 compared to the same period in 2019 (in millions):

	Alliant Energy			IPL			WPL
Changes in the amount of cash receipts on sold receivables		$62			$62			$—
Refund from ATC in 2020 for construction deposits WPL previously provided to ATC for transmission network upgrades for West Riverside	42			—			42
Lower (higher) utility construction and acquisition expenditures (a)	69			231			(162		)
Expenditures for new acquisitions at AEF in 2019	13			—			—
Other	(4		)	(11		)	(10		)
		$182			$282			($130	)

(a) Largely due to lower expenditures for IPL’s expansion of wind generation, IPL’s advanced metering infrastructure and WPL’s West Riverside Energy Center, partially offset by higher expenditures for IPL’s and WPL’s electric and gas distribution systems (which include the derecho windstorm) and WPL’s expansion of wind generation.

Construction and Acquisition Expenditures - Construction and acquisition expenditures for 2020 through 2024 are currently anticipated as follows (in millions). Cost estimates represent Alliant Energy’s, IPL’s and WPL’s portion of construction expenditures and exclude allowance for funds used during construction and capitalized interest, if applicable. Such estimates do not include IPL’s September 2020 $110 million buyout payment related to the DAEC PPA, do not reflect any potential proceeds if neighboring utilities exercise options for a partial ownership in West Riverside, and do not reflect the assumed portion of construction costs that are expected to be financed by tax equity partners, as discussed below in “IPL and WPL Solar Project Tax Equity Credits.” Refer to “2020 Highlights” for discussion of IPL’s and WPL’s planned new solar generation (such amounts are included in the “Renewable projects” line in the table below).

	Alliant Energy										IPL										WPL
	2020		2021		2022		2023		2024		2020		2021		2022		2023		2024		2020		2021		2022		2023		2024
Generation:
Renewable projects		$265		$485		$750		$635		$320		$120		$45		$270		$270		$50		$145		$440		$480		$365		$270
Other	150		90		180		175		90		50		45		135		135		55		100		45		45		40		35
Distribution:
Electric systems	675		470		435		535		695		420		240		225		290		375		255		230		210		245		320
Gas systems	170		70		75		70		70		50		35		40		30		30		120		35		35		40		40
Other	120		180		185		190		195		30		10		10		10		25		10		15		10		10		10
		$1,380		$1,295		$1,625		$1,605		$1,370		$670		$375		$680		$735		$535		$630		$765		$780		$700		$675

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Financing Activities - The following items contributed to increased (decreased) financing activity cash flows for the nine months ended September 30, 2020 compared to the same period in 2019 (in millions):

	Alliant Energy			IPL			WPL
Lower (higher) payments to retire long-term debt		($401	)		($200	)		$100
Net changes in the amount of commercial paper outstanding	177			50			76
Higher (lower) net proceeds from issuance of long-term debt	100			(200		)	—
Higher net proceeds from common stock issuances	56			—			—
Higher (lower) capital contributions from IPL’s and WPL’s parent company, Alliant Energy	—			245			(75		)
Other (includes higher dividend payments in 2020)	(39		)	(54		)	(16		)
		($107	)		($159	)		$85

IPL and WPL Solar Project Tax Equity Credits - IPL and WPL each propose to own and operate their planned solar projects, which are currently expected to qualify for 30% investment tax credits, through a tax equity partnership, with approximately 35% to 45% of the construction costs financed with capital from the tax equity partner. This would allow IPL’s and WPL’s customers to share the costs of the solar projects with an investment partner for 10 years or less, while ensuring their customers receive energy, capacity, and renewable energy credit benefits from the projects. IPL and WPL would expect to purchase the tax equity partner’s interest in the solar projects within 10 years of operation, and then convert to a traditional ownership structure for the remainder of the useful life of the projects. Assuming a portion of the construction costs are financed by the tax equity partner, IPL would receive approximately $205 million from the tax equity partner in 2023, and WPL would receive approximately $210 million in 2022 and $275 million in 2023. IPL and WPL would expect to include their portion of capital expenditures, less the amounts financed by the tax equity partner, in their respective rate base.

State Regulatory Financing Authorizations - In September 2020, WPL received authorization from the PSCW to issue up to $1 billion of long-term debt securities in aggregate through December 2023.

Common Stock Issuances and Common Stock Dividends - Refer to Note 5 for discussion of common stock issuances by Alliant Energy in 2020. Refer to “Results of Operations” for discussion of expected common stock dividends in 2021.

Long-term Debt - Refer to Note 6(b) for discussion of IPL’s, WPL’s and AEF’s issuances and retirements of long-term debt in 2020. Refer to “Results of Operations” for discussion of expected issuances of long-term debt in 2021.

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 2019 Form 10-K and has not changed materially from the items reported in the 2019 Form 10-K, except for the items described in Notes 3, 6 and 13.

OTHER MATTERS

Critical Accounting Policies and Estimates - The summary of critical accounting policies and estimates included in the 2019 Form 10-K has not changed materially, except as described below.

Contingencies - Effective January 1, 2020 upon the adoption of the new accounting standard for credit losses, certain contingencies, such as Alliant Energy Resources, LLC’s guarantees of the partnership obligations of an affiliate of Whiting Petroleum, require estimation each reporting period of the expected credit losses on those contingencies. These estimates require significant judgment and would result in recognition of a credit loss liability sooner than the previous accounting standards, which required recognition when the contingency became probable and could be reasonably estimated based on then currently available information. With respect to Alliant Energy’s guarantees of the partnership obligations of an affiliate of Whiting Petroleum, the most significant judgments in determining the credit loss liability were the estimate of the exposure under the guarantees and the methodology used for calculating the credit loss liability. As of September 30, 2020, Alliant Energy currently estimates the exposure to be a portion of the known partnership abandonment obligations. The methodology used to determine the credit loss liability considers both quantitative and qualitative information, which utilizes potential outcomes in a range of possible estimated amounts. Factors considered include market and external data points, the creditworthiness of the other partners, Whiting Petroleum’s emergence from bankruptcy in the third quarter of 2020, and a portion of forecasted cash flow expenditures associated with the abandonment obligations based on information made available to Alliant Energy. Note 1(c) provides discussion of the adoption of the new accounting standard for credit losses. Note 13(c) provides further discussion of contingencies assessed at January 1, 2020 and September 30, 2020, including impacts to Alliant Energy Resources, LLC’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum and to the other partners, as well as adjustments to the credit loss liability recorded in the third quarter of 2020.

ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

Quantitative and Qualitative Disclosures About Market Risk are reported in the 2019 Form 10-K and have not changed materially.

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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 of September 30, 2020 pursuant to the requirements of the Securities Exchange Act of 1934, as amended. Based on their evaluation, the Chief Executive Officer and the Chief Financial Officer concluded that Alliant Energy’s, IPL’s and WPL’s disclosure controls and procedures were effective as of the quarter ended September 30, 2020.

There was no change in Alliant Energy’s, IPL’s and WPL’s internal control over financial reporting that occurred during the quarter ended September 30, 2020 that has materially affected, or is reasonably likely to materially affect, Alliant Energy’s, IPL’s or WPL’s internal control over financial reporting. Alliant Energy, IPL and WPL have not experienced any material impact to their internal control over financial reporting due to the COVID-19 pandemic, and continue to monitor and assess the impact COVID-19 has on their internal controls.

PART II. OTHER INFORMATION

ITEM 1A. RISK FACTORS

The risk factors described in Item 1A in the 2019 Form 10-K have not changed materially, except as described below.

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

Although we expect an increase in residential sales due to these closures, our commercial and industrial sales may be significantly reduced. The negative impacts on the economy could adversely impact the market value of the assets that fund our pension plans, which could necessitate accelerated funding of the plans to meet minimum federal government requirements. The negative impacts on the economy could also adversely impact the ability of counterparties to meet contractual payment obligations, including guarantees, or deliver contracted commodities and other goods or services at the contracted price, which could increase company expenses. Our access to the capital markets could be adversely affected by COVID-19, which could cause us to need alternative sources of funding for our operations and for working capital, any of which could increase our cost of capital.

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

The degree to which COVID-19 may impact our business operations, financial condition and results of operations is unknown at this time and will depend on future developments, including the ultimate geographic spread of COVID-19, the severity of the disease, the duration of the outbreak, possible resurgence of the disease at a later date, and further actions that may be taken by governmental and regulatory authorities.

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

A summary of Alliant Energy common stock repurchases for the quarter ended September 30, 2020 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)
July 1 through July 31	4,009		$49.07	—	N/A
August 1 through August 31	2,680	53.91		—	N/A
September 1 through September 30	64	52.11		—	N/A
	6,753	51.02		—

(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 6. EXHIBITS

The following Exhibits are filed herewith or incorporated herein by reference.

Exhibit Number	Description
3.1	Amended and Restated Bylaws of Alliant Energy, effective October 27, 2020 (incorporated by reference to Exhibit 3.1 to Alliant Energy’s Form 8-K, filed October 29, 2020 (File No. 1-9894))
3.2	Amended and Restated Bylaws of IPL, effective October 27, 2020 (incorporated by reference to Exhibit 3.2 to IPL’s Form 8-K, filed October 29, 2020 (File No. 1-4117))
3.3	Amended and Restated Bylaws of WPL, effective October 27, 2020 (incorporated by reference to Exhibit 3.3 to WPL’s Form 8-K, filed October 29, 2020 (File No. 0-337))
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)

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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 3rd day of November 2020.

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)

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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: November 3, 2020

/s/ John O. Larsen

John O. Larsen

Chairman, President and Chief Executive Officer

EX-31.2

Exhibit 31.2

Certification of the Chief Financial Officer for Alliant Energy Corporation

I, Robert J. Durian, certify that:

1. I have reviewed this 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: November 3, 2020

/s/ Robert J. Durian

Robert J. Durian

Executive Vice President and Chief Financial Officer

EX-31.3

Exhibit 31.3

Certification of the Chief Executive Officer for Interstate Power and Light Company

I, John O. Larsen, certify that:

1. I have reviewed this 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: November 3, 2020

/s/ John O. Larsen

John O. Larsen

Chairman and Chief Executive Officer

EX-31.4

Exhibit 31.4

Certification of the Chief Financial Officer for Interstate Power and Light Company

I, Robert J. Durian, certify that:

1. I have reviewed this 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 rolein the registrant’s internal control over financial reporting.

Date: November 3, 2020

/s/ Robert J. Durian

Robert J. Durian

Executive Vice President and Chief Financial Officer

EX-31.5

Exhibit 31.5

Certification of the Chief Executive Officer for Wisconsin Power and Light Company

I, John O. Larsen, certify that:

1. I have reviewed this 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: November 3, 2020

/s/ John O. Larsen

John O. Larsen

Chairman and Chief Executive Officer

EX-31.6

Exhibit 31.6

Certification of the Chief Financial Officer for Wisconsin Power and Light Company

I, Robert J. Durian, certify that:

1. I have reviewed this 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: November 3, 2020

/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 September 30, 2020 (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

Chairman, President and Chief Executive Officer

/s/ Robert J. Durian

Robert J. Durian

Executive Vice President and Chief Financial Officer

November 3, 2020

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 September 30, 2020 (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

Chairman and Chief Executive Officer

/s/ Robert J. Durian

Robert J. Durian

Executive Vice President and Chief Financial Officer

November 3, 2020

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 September 30, 2020 (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

Chairman and Chief Executive Officer

/s/ Robert J. Durian

Robert J. Durian

Executive Vice President and Chief Financial Officer

November 3, 2020

XML

Document And Entity Information	9 Months Ended
	Sep. 30, 2020 shares
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
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	249,760,663
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
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
Title of 12(b) Security	5.100% Series D Cumulative Perpetual Preferred Stock, $0.01 Par Value
Trading Symbol	IPLDP
Security Exchange Name	NASDAQ
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 Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Electric utility	$ 852	$ 916	$ 2,257	$ 2,350
Gas utility	42	42	253	323
Other utility	10	11	32	33
Non-utility	16	21	57	62
Total revenues	920	990	2,599	2,768
Operating expenses:
Electric production fuel and purchased power	179	219	527	602
Electric transmission service	132	127	326	363
Cost of gas sold	11	9	117	151
Other operation and maintenance	143	174	465	527
Depreciation and amortization	156	144	454	424
Taxes other than income taxes	27	27	82	84
Total operating expenses	648	700	1,971	2,151
Operating income	272	290	628	617
Other (income) and deductions:
Interest expense	68	68	207	204
Equity income from unconsolidated investments, net	(15)	(12)	(46)	(35)
Allowance for funds used during construction	(13)	(22)	(51)	(66)
Other	3	4	7	11
Total other (income) and deductions	43	38	117	114
Income before income taxes	229	252	511	503
Income tax expense (benefit)	(20)	23	(47)	49
Net income	249	229	558	454
Preferred dividend requirements of Interstate Power and Light Company	3	3	8	8
Net income attributable to common shareowners	$ 246	$ 226	$ 550	$ 446
Weighted average number of common shares outstanding:
Basic (in shares)	249.7	239.1	247.9	237.7
Diluted (in shares)	250.0	239.9	248.1	238.2
Earnings per weighted average common share attributable to Alliant Energy common shareowners:
Basic (in dollars per share)	$ 0.99	$ 0.95	$ 2.22	$ 1.88
Diluted (in dollars per share)	$ 0.98	$ 0.94	$ 2.22	$ 1.87
IPL [Member]
Revenues:
Electric utility	$ 519	$ 561	$ 1,332	$ 1,373
Gas utility	24	25	141	188
Other utility	10	11	31	32
Total revenues	553	597	1,504	1,593
Operating expenses:
Electric production fuel and purchased power	102	127	304	339
Electric transmission service	93	92	212	257
Cost of gas sold	6	6	63	80
Other operation and maintenance	85	100	269	306
Depreciation and amortization	89	84	264	243
Taxes other than income taxes	16	14	45	46
Total operating expenses	391	423	1,157	1,271
Operating income	162	174	347	322
Other (income) and deductions:
Interest expense	35	32	104	93
Allowance for funds used during construction	(6)	(11)	(21)	(34)
Other	1	2	3	5
Total other (income) and deductions	30	23	86	64
Income before income taxes	132	151	261	258
Income tax expense (benefit)	(19)	7	(37)	11
Net income	151	144	298	247
Preferred dividend requirements of Interstate Power and Light Company	3	3	8	8
Net income attributable to common shareowners	148	141	290	239
WPL [Member]
Revenues:
Electric utility	333	355	925	977
Gas utility	18	17	112	135
Other utility	0	0	1	1
Total revenues	351	372	1,038	1,113
Operating expenses:
Electric production fuel and purchased power	78	92	223	263
Electric transmission service	39	36	114	106
Cost of gas sold	4	3	53	71
Other operation and maintenance	65	62	172	188
Depreciation and amortization	65	59	186	177
Taxes other than income taxes	11	12	35	35
Total operating expenses	262	264	783	840
Operating income	89	108	255	273
Other (income) and deductions:
Interest expense	26	25	78	77
Allowance for funds used during construction	(6)	(11)	(29)	(31)
Other	1	1	3	4
Total other (income) and deductions	21	15	52	50
Income before income taxes	68	93	203	223
Income tax expense (benefit)	(5)	17	(17)	40
Net income	$ 73	$ 76	$ 220	$ 183

XML

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 189	$ 16
Accounts receivable, less allowance for expected credit losses	399	402
Production fuel, at weighted average cost	62	78
Gas stored underground, at weighted average cost	48	49
Materials and supplies, at weighted average cost	113	100
Regulatory assets	74	87
Prepaid gross receipts tax	30	42
Other	118	102
Total current assets	1,033	876
Property, plant and equipment, net	14,199	13,527
Investments:
ATC Holdings	328	320
Other	150	148
Total investments	478	468
Other assets:
Regulatory assets	1,762	1,758
Deferred charges and other	68	72
Total other assets	1,830	1,830
Total assets	17,540	16,701
Current liabilities:
Current maturities of long-term debt	7	657
Commercial paper	422	337
Accounts payable	417	422
Regulatory liabilities	163	212
Other	286	426
Total current liabilities	1,295	2,054
Long-term debt, net (excluding current portion)	6,574	5,533
Other liabilities:
Deferred tax liabilities	1,803	1,714
Regulatory liabilities	1,188	1,212
Pension and other benefit obligations	423	484
Other	348	299
Total other liabilities	3,762	3,709
Commitments and contingencies (Note 13)
Common equity:
Common stock	2	2
Additional paid-in capital	2,693	2,446
Retained earnings	3,026	2,766
Accumulated other comprehensive income (loss)	(1)	1
Shares in deferred compensation trust - 374,246 and 381,232 shares at a weighted average cost of $28.28 and $26.24 per share	(11)	(10)
Total common equity	5,709	5,205
Cumulative preferred stock of Interstate Power and Light Company	200	200
Total equity	5,909	5,405
Total liabilities and equity	17,540	16,701
IPL [Member]
Current assets:
Cash and cash equivalents	185	9
Accounts receivable, less allowance for expected credit losses	219	203
Production fuel, at weighted average cost	45	47
Gas stored underground, at weighted average cost	21	22
Materials and supplies, at weighted average cost	63	55
Regulatory assets	52	44
Other	53	29
Total current assets	638	409
Property, plant and equipment, net	7,818	7,481
Other assets:
Regulatory assets	1,366	1,356
Deferred charges and other	36	31
Total other assets	1,402	1,387
Total assets	9,858	9,277
Current liabilities:
Current maturities of long-term debt	0	200
Accounts payable	231	207
Regulatory liabilities	117	116
Other	198	307
Total current liabilities	546	830
Long-term debt, net (excluding current portion)	3,344	2,947
Other liabilities:
Deferred tax liabilities	1,028	1,008
Regulatory liabilities	574	599
Pension and other benefit obligations	149	168
Other	287	253
Total other liabilities	2,038	2,028
Commitments and contingencies (Note 13)
Common equity:
Common stock	33	33
Additional paid-in capital	2,693	2,348
Retained earnings	1,004	891
Total common equity	3,730	3,272
Cumulative preferred stock of Interstate Power and Light Company	200	200
Total equity	3,930	3,472
Total liabilities and equity	9,858	9,277
WPL [Member]
Current assets:
Cash and cash equivalents	2	4
Accounts receivable, less allowance for expected credit losses	170	191
Production fuel, at weighted average cost	17	31
Gas stored underground, at weighted average cost	27	27
Materials and supplies, at weighted average cost	48	43
Regulatory assets	22	43
Prepaid gross receipts tax	30	42
Other	22	62
Total current assets	338	443
Property, plant and equipment, net	5,977	5,638
Other assets:
Regulatory assets	396	402
Deferred charges and other	33	24
Total other assets	429	426
Total assets	6,744	6,507
Current liabilities:
Current maturities of long-term debt	0	150
Commercial paper	139	168
Accounts payable	126	160
Regulatory liabilities	46	96
Other	117	116
Total current liabilities	428	690
Long-term debt, net (excluding current portion)	2,130	1,783
Other liabilities:
Deferred tax liabilities	696	626
Regulatory liabilities	614	613
Finance lease obligations - Sheboygan Falls Energy Facility	44	51
Pension and other benefit obligations	189	211
Other	161	169
Total other liabilities	1,704	1,670
Commitments and contingencies (Note 13)
Common equity:
Common stock	66	66
Additional paid-in capital	1,459	1,434
Retained earnings	957	864
Total common equity	2,482	2,364
Total equity	2,482	2,364
Total liabilities and equity	$ 6,744	$ 6,507

XML

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2020	Dec. 31, 2019
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)	249,760,663	245,022,800
Shares in deferred compensation trust (in shares)	374,246	381,232
Shares in deferred compensation trust, weighted average cost per share (in dollars per share)	$ 28.28	$ 26.24
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)	$ 5.00	$ 5.00
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	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income	$ 558	$ 454
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	454	424
Deferred tax expense (benefit) and tax credits	(48)	53
Equity component of allowance for funds used during construction	(36)	(46)
Other	19	17
Other changes in assets and liabilities:
Accounts receivable	(316)	(359)
Regulatory liabilities	(72)	(12)
Deferred income taxes	143	45
Pension and other benefit obligations	(61)	(33)
DAEC PPA amendment buyout payment	(110)	0
Other	(95)	(34)
Net cash flows from operating activities	436	509
Cash flows used for investing activities:
Utility business construction and acquisition expenditures	(935)	(1,004)
Other construction and acquisition expenditures	(39)	(71)
Cash receipts on sold receivables	318	256
Other	(23)	(42)
Net cash flows used for investing activities	(679)	(861)
Cash flows from (used for) financing activities:
Common stock dividends	(281)	(253)
Proceeds from issuance of common stock, net	241	185
Proceeds from issuance of long-term debt	1,050	950
Payments to retire long-term debt	(654)	(253)
Net change in commercial paper	85	(92)
Other	(22)	(11)
Net cash flows from (used for) financing activities	419	526
Net increase (decrease) in cash, cash equivalents and restricted cash	176	174
Cash, cash equivalents and restricted cash at beginning of period	18	26
Cash, cash equivalents and restricted cash at end of period	194	200
Supplemental cash flows information:
Interest	(197)	(195)
Income taxes, net	6	1
Significant non-cash investing and financing activities:
Accrued capital expenditures	202	254
Beneficial interest obtained in exchange for securitized accounts receivable	201	237
IPL [Member]
Cash flows from operating activities:
Net income	298	247
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	264	243
Deferred tax expense (benefit) and tax credits	(42)	(14)
Equity component of allowance for funds used during construction	(15)	(25)
Other	6	2
Other changes in assets and liabilities:
Accounts receivable	(337)	(365)
Regulatory assets	(32)	(13)
Deferred income taxes	62	32
Pension and other benefit obligations	(19)	(13)
DAEC PPA amendment buyout payment	(110)	0
Other	(56)	45
Net cash flows from operating activities	19	139
Cash flows used for investing activities:
Utility business construction and acquisition expenditures	(465)	(696)
Cash receipts on sold receivables	318	256
Other	(55)	(44)
Net cash flows used for investing activities	(202)	(484)
Cash flows from (used for) financing activities:
Common stock dividends	(177)	(126)
Capital contributions from parent	345	100
Proceeds from issuance of long-term debt	400	600
Payments to retire long-term debt	(200)	0
Net change in commercial paper	0	(50)
Other	(9)	(6)
Net cash flows from (used for) financing activities	359	518
Net increase (decrease) in cash, cash equivalents and restricted cash	176	173
Cash, cash equivalents and restricted cash at beginning of period	9	12
Cash, cash equivalents and restricted cash at end of period	185	185
Supplemental cash flows information:
Interest	(109)	(94)
Income taxes, net	(12)	8
Significant non-cash investing and financing activities:
Accrued capital expenditures	150	180
Beneficial interest obtained in exchange for securitized accounts receivable	201	237
WPL [Member]
Cash flows from operating activities:
Net income	220	183
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	186	177
Deferred tax expense (benefit) and tax credits	(9)	55
Other	(8)	(8)
Other changes in assets and liabilities:
Regulatory liabilities	(61)	(29)
Deferred income taxes	79	16
Other	(5)	(34)
Net cash flows from operating activities	402	360
Cash flows used for investing activities:
Utility business construction and acquisition expenditures	(470)	(308)
Other	5	(27)
Net cash flows used for investing activities	(465)	(335)
Cash flows from (used for) financing activities:
Common stock dividends	(127)	(108)
Capital contributions from parent	25	100
Proceeds from issuance of long-term debt	350	350
Payments to retire long-term debt	(150)	(250)
Net change in commercial paper	(29)	(105)
Other	(8)	(11)
Net cash flows from (used for) financing activities	61	(24)
Net increase (decrease) in cash, cash equivalents and restricted cash	(2)	1
Cash, cash equivalents and restricted cash at beginning of period	4	9
Cash, cash equivalents and restricted cash at end of period	2	10
Supplemental cash flows information:
Interest	(71)	(74)
Income taxes, net	5	(7)
Significant non-cash investing and financing activities:
Accrued capital expenditures	$ 50	$ 70

XML

Summary Of Significant Accounting Policies

9 Months Ended

Sep. 30, 2020

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 Securities and Exchange Commission. 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 latest combined Annual Report on 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 nine months ended September 30, 2020 are not necessarily indicative of results that may be expected for the year ending December 31, 2020.

In March 2020, COVID-19 was declared a global pandemic, which has resulted in widespread travel restrictions, closures of commercial spaces and industrial facilities, and more people working from home in Alliant Energy’s service territories. For the three and nine months ended September 30, 2020, Alliant Energy, IPL and WPL considered the impact of COVID-19 on their overall business operations, financial condition, results of operations and cash flows, along with assumptions and estimates used. While the total expected impact of COVID-19 on future sales is currently unknown, Alliant Energy, IPL and WPL have experienced higher electric residential sales and lower electric commercial and industrial sales since the outset of the pandemic. The degree to which the COVID-19 pandemic may impact Alliant Energy, IPL and WPL in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities.

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 1(b) Cash and Cash Equivalents - At September 30, 2020, Alliant Energy’s and IPL’s cash and cash equivalents included $183 million and $183 million of money market fund investments, with weighted average interest rates of 0.1% and 0.1%, respectively.

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

NOTE 1(d) New Accounting Standards -

Credit Losses - In June 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 13(c) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s summary of changes in shareowners’ equity in Note 5 for the nine months ended September 30, 2020.

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 Securities and Exchange Commission. 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 latest combined Annual Report on 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 nine months ended September 30, 2020 are not necessarily indicative of results that may be expected for the year ending December 31, 2020.

In March 2020, COVID-19 was declared a global pandemic, which has resulted in widespread travel restrictions, closures of commercial spaces and industrial facilities, and more people working from home in Alliant Energy’s service territories. For the three and nine months ended September 30, 2020, Alliant Energy, IPL and WPL considered the impact of COVID-19 on their overall business operations, financial condition, results of operations and cash flows, along with assumptions and estimates used. While the total expected impact of COVID-19 on future sales is currently unknown, Alliant Energy, IPL and WPL have experienced higher electric residential sales and lower electric commercial and industrial sales since the outset of the pandemic. The degree to which the COVID-19 pandemic may impact Alliant Energy, IPL and WPL in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities.

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 1(b) Cash and Cash Equivalents - At September 30, 2020, Alliant Energy’s and IPL’s cash and cash equivalents included $183 million and $183 million of money market fund investments, with weighted average interest rates of 0.1% and 0.1%, respectively.

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

NOTE 1(d) New Accounting Standards -

Credit Losses - In June 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 13(c) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s summary of changes in shareowners’ equity in Note 5 for the nine months ended September 30, 2020.

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 Securities and Exchange Commission. 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 latest combined Annual Report on 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 nine months ended September 30, 2020 are not necessarily indicative of results that may be expected for the year ending December 31, 2020.

In March 2020, COVID-19 was declared a global pandemic, which has resulted in widespread travel restrictions, closures of commercial spaces and industrial facilities, and more people working from home in Alliant Energy’s service territories. For the three and nine months ended September 30, 2020, Alliant Energy, IPL and WPL considered the impact of COVID-19 on their overall business operations, financial condition, results of operations and cash flows, along with assumptions and estimates used. While the total expected impact of COVID-19 on future sales is currently unknown, Alliant Energy, IPL and WPL have experienced higher electric residential sales and lower electric commercial and industrial sales since the outset of the pandemic. The degree to which the COVID-19 pandemic may impact Alliant Energy, IPL and WPL in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities.

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 1(b) Cash and Cash Equivalents - At September 30, 2020, Alliant Energy’s and IPL’s cash and cash equivalents included $183 million and $183 million of money market fund investments, with weighted average interest rates of 0.1% and 0.1%, respectively.

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

NOTE 1(d) New Accounting Standards -

Credit Losses - In June 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 13(c) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s summary of changes in shareowners’ equity in Note 5 for the nine months ended September 30, 2020.

XML

Regulatory Matters

9 Months Ended

Sep. 30, 2020

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
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Tax-related		$877		$818		$829		$777		$48		$41
Pension and OPEB costs	492		524		247		263		245		261
Assets retired early	118		134		79		88		39		46
Asset retirement obligations	115		112		79		76		36		36
IPL’s DAEC PPA amendment	110		108		110		108		—		—
Derivatives	20		39		8		18		12		21
Emission allowances	19		21		19		21		—		—
Other	85		89		47		49		38		40
		$1,836		$1,845		$1,418		$1,400		$418		$445

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

	Alliant Energy				IPL				WPL
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Tax-related		$746		$836		$334		$351		$412		$485
Cost of removal obligations	371		388		241		257		130		131
Electric transmission cost recovery	62		88		30		51		32		37
Derivatives	40		20		27		17		13		3
WPL’s West Riverside liquidated damages	36		—		—		—		36		—
Commodity cost recovery	22		24		19		9		3		15
WPL’s earnings sharing mechanism	22		22		—		—		22		22
Other	52		46		40		30		12		16
		$1,351		$1,424		$691		$715		$660		$709

Tax-related - Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities are primarily related to excess deferred tax benefits resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform. During the nine months ended September 30, 2020, Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities decreased primarily from returning a portion of these excess deferred tax benefits back to customers.

IPL’s DAEC PPA amendment - In September 2020, IPL made a buyout payment of $110 million in exchange for shortening the term of its DAEC PPA by 5 years. The payment was recorded as a reduction to “Other current liabilities” on Alliant Energy’s and IPL’s balance sheets and was included in “DAEC PPA amendment buyout payment” in Alliant Energy’s and IPL’s cash flows used for operating activities for the nine months ended September 30, 2020. The buyout payment will be recovered from IPL’s retail and wholesale customers beginning in the fourth quarter of 2020 through the end of 2025.

Electric transmission cost recovery - In the second quarter of 2020, pursuant to a June 2020 IUB order, IPL issued $42 million of credits to its retail electric customers through its transmission cost rider for amounts previously collected in rates, which resulted in a corresponding reduction to “Electric transmission service” expense in Alliant Energy’s and IPL’s income statements for the nine months ended September 30, 2020.

Refer to Note 13(f) for discussion of refunds received by IPL and WPL in 2020 related to MISO transmission owner return on equity complaints.

WPL’s West Riverside liquidated damages - Pursuant to terms included in the related West Riverside construction procurement contracts, WPL reached agreement with the contractor on liquidated damages in the third quarter of 2020. A significant portion of the liquidated damages was settled by WPL offsetting amounts owed to the contractor that were previously withheld for payment, which were non-cash investing activities. The liquidated damages are expected to be returned to WPL’s customers as determined in future regulatory proceedings.

August 2020 Derecho Windstorm - In August 2020, a derecho windstorm caused considerable damage to IPL’s electric distribution system in its service territory, and over 250,000 of its customers lost power. IPL completed its initial restoration and rebuilding efforts in August 2020 and expects permanent repairs to the system to continue throughout 2020. IPL’s current estimate of the total cost of the windstorm is approximately $140 million, and as of September 30, 2020, approximately $130 million was recorded substantially to “Property, plant and equipment, net” on Alliant Energy’s and IPL’s balance sheets. Tax benefits and the incremental operation and maintenance expenses resulting from the windstorm were deferred and recorded

as a net regulatory liability of $7 million as of September 30, 2020, which is included in “Other” regulatory liabilities in the above table. In November 2020, IPL filed a request with the IUB for utilization of a regulatory account to track certain incremental costs and benefits incurred resulting from the windstorm until IPL’s next rate proceeding.

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
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Tax-related		$877		$818		$829		$777		$48		$41
Pension and OPEB costs	492		524		247		263		245		261
Assets retired early	118		134		79		88		39		46
Asset retirement obligations	115		112		79		76		36		36
IPL’s DAEC PPA amendment	110		108		110		108		—		—
Derivatives	20		39		8		18		12		21
Emission allowances	19		21		19		21		—		—
Other	85		89		47		49		38		40
		$1,836		$1,845		$1,418		$1,400		$418		$445

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

	Alliant Energy				IPL				WPL
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Tax-related		$746		$836		$334		$351		$412		$485
Cost of removal obligations	371		388		241		257		130		131
Electric transmission cost recovery	62		88		30		51		32		37
Derivatives	40		20		27		17		13		3
WPL’s West Riverside liquidated damages	36		—		—		—		36		—
Commodity cost recovery	22		24		19		9		3		15
WPL’s earnings sharing mechanism	22		22		—		—		22		22
Other	52		46		40		30		12		16
		$1,351		$1,424		$691		$715		$660		$709

Tax-related - Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities are primarily related to excess deferred tax benefits resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform. During the nine months ended September 30, 2020, Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities decreased primarily from returning a portion of these excess deferred tax benefits back to customers.

IPL’s DAEC PPA amendment - In September 2020, IPL made a buyout payment of $110 million in exchange for shortening the term of its DAEC PPA by 5 years. The payment was recorded as a reduction to “Other current liabilities” on Alliant Energy’s and IPL’s balance sheets and was included in “DAEC PPA amendment buyout payment” in Alliant Energy’s and IPL’s cash flows used for operating activities for the nine months ended September 30, 2020. The buyout payment will be recovered from IPL’s retail and wholesale customers beginning in the fourth quarter of 2020 through the end of 2025.

Electric transmission cost recovery - In the second quarter of 2020, pursuant to a June 2020 IUB order, IPL issued $42 million of credits to its retail electric customers through its transmission cost rider for amounts previously collected in rates, which resulted in a corresponding reduction to “Electric transmission service” expense in Alliant Energy’s and IPL’s income statements for the nine months ended September 30, 2020.

Refer to Note 13(f) for discussion of refunds received by IPL and WPL in 2020 related to MISO transmission owner return on equity complaints.

WPL’s West Riverside liquidated damages - Pursuant to terms included in the related West Riverside construction procurement contracts, WPL reached agreement with the contractor on liquidated damages in the third quarter of 2020. A significant portion of the liquidated damages was settled by WPL offsetting amounts owed to the contractor that were previously withheld for payment, which were non-cash investing activities. The liquidated damages are expected to be returned to WPL’s customers as determined in future regulatory proceedings.

August 2020 Derecho Windstorm - In August 2020, a derecho windstorm caused considerable damage to IPL’s electric distribution system in its service territory, and over 250,000 of its customers lost power. IPL completed its initial restoration and rebuilding efforts in August 2020 and expects permanent repairs to the system to continue throughout 2020. IPL’s current estimate of the total cost of the windstorm is approximately $140 million, and as of September 30, 2020, approximately $130 million was recorded substantially to “Property, plant and equipment, net” on Alliant Energy’s and IPL’s balance sheets. Tax benefits and the incremental operation and maintenance expenses resulting from the windstorm were deferred and recorded

as a net regulatory liability of $7 million as of September 30, 2020, which is included in “Other” regulatory liabilities in the above table. In November 2020, IPL filed a request with the IUB for utilization of a regulatory account to track certain incremental costs and benefits incurred resulting from the windstorm until IPL’s next rate proceeding.

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
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Tax-related		$877		$818		$829		$777		$48		$41
Pension and OPEB costs	492		524		247		263		245		261
Assets retired early	118		134		79		88		39		46
Asset retirement obligations	115		112		79		76		36		36
IPL’s DAEC PPA amendment	110		108		110		108		—		—
Derivatives	20		39		8		18		12		21
Emission allowances	19		21		19		21		—		—
Other	85		89		47		49		38		40
		$1,836		$1,845		$1,418		$1,400		$418		$445

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

	Alliant Energy				IPL				WPL
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Tax-related		$746		$836		$334		$351		$412		$485
Cost of removal obligations	371		388		241		257		130		131
Electric transmission cost recovery	62		88		30		51		32		37
Derivatives	40		20		27		17		13		3
WPL’s West Riverside liquidated damages	36		—		—		—		36		—
Commodity cost recovery	22		24		19		9		3		15
WPL’s earnings sharing mechanism	22		22		—		—		22		22
Other	52		46		40		30		12		16
		$1,351		$1,424		$691		$715		$660		$709

Tax-related - Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities are primarily related to excess deferred tax benefits resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform. During the nine months ended September 30, 2020, Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities decreased primarily from returning a portion of these excess deferred tax benefits back to customers.

IPL’s DAEC PPA amendment - In September 2020, IPL made a buyout payment of $110 million in exchange for shortening the term of its DAEC PPA by 5 years. The payment was recorded as a reduction to “Other current liabilities” on Alliant Energy’s and IPL’s balance sheets and was included in “DAEC PPA amendment buyout payment” in Alliant Energy’s and IPL’s cash flows used for operating activities for the nine months ended September 30, 2020. The buyout payment will be recovered from IPL’s retail and wholesale customers beginning in the fourth quarter of 2020 through the end of 2025.

Electric transmission cost recovery - In the second quarter of 2020, pursuant to a June 2020 IUB order, IPL issued $42 million of credits to its retail electric customers through its transmission cost rider for amounts previously collected in rates, which resulted in a corresponding reduction to “Electric transmission service” expense in Alliant Energy’s and IPL’s income statements for the nine months ended September 30, 2020.

Refer to Note 13(f) for discussion of refunds received by IPL and WPL in 2020 related to MISO transmission owner return on equity complaints.

WPL’s West Riverside liquidated damages - Pursuant to terms included in the related West Riverside construction procurement contracts, WPL reached agreement with the contractor on liquidated damages in the third quarter of 2020. A significant portion of the liquidated damages was settled by WPL offsetting amounts owed to the contractor that were previously withheld for payment, which were non-cash investing activities. The liquidated damages are expected to be returned to WPL’s customers as determined in future regulatory proceedings.

August 2020 Derecho Windstorm - In August 2020, a derecho windstorm caused considerable damage to IPL’s electric distribution system in its service territory, and over 250,000 of its customers lost power. IPL completed its initial restoration and rebuilding efforts in August 2020 and expects permanent repairs to the system to continue throughout 2020. IPL’s current estimate of the total cost of the windstorm is approximately $140 million, and as of September 30, 2020, approximately $130 million was recorded substantially to “Property, plant and equipment, net” on Alliant Energy’s and IPL’s balance sheets. Tax benefits and the incremental operation and maintenance expenses resulting from the windstorm were deferred and recorded

as a net regulatory liability of $7 million as of September 30, 2020, which is included in “Other” regulatory liabilities in the above table. In November 2020, IPL filed a request with the IUB for utilization of a regulatory account to track certain incremental costs and benefits incurred resulting from the windstorm until IPL’s next rate proceeding.

XML

Receivables

9 Months Ended

Sep. 30, 2020

Receivables [Line Items]

Receivables

RECEIVABLES

Note 3(a) Accounts Receivable - Details for accounts receivable included on the balance sheets were as follows (in millions):

	Alliant Energy						IPL						WPL
	September 30, 2020			December 31, 2019			September 30, 2020			December 31, 2019			September 30, 2020			December 31, 2019
Customer		$95			$92			$—			$—			$86			$84
Unbilled utility revenues	62			82			—			—			62			82
Deferred proceeds	201			188			201			188			—			—
Other	54			47			20			16			33			31
Allowance for expected credit losses	(13		)	(7		)	(2		)	(1		)	(11		)	(6		)
		$399			$402			$219			$203			$170			$191

Note 3(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. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. As of September 30, 2020, IPL had $109 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 nine months ended September 30 were as follows (in millions):

	Three Months				Nine Months
	2020		2019		2020		2019
Maximum outstanding aggregate cash proceeds		$1		$103		$96		$108
Average outstanding aggregate cash proceeds	1		45		12		43

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

	September 30, 2020		December 31, 2019
Customer accounts receivable		$148		$125
Unbilled utility revenues	67		95
Other receivables	—		1
Receivables sold to third party	215		221
Less: cash proceeds	1		27
Deferred proceeds	214		194
Less: allowance for expected credit losses	13		6
Fair value of deferred proceeds		$201		$188

As of September 30, 2020, outstanding receivables past due under the Receivables Agreement were $27 million. Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and nine months ended September 30 were as follows (in millions):

	Three Months				Nine Months
	2020		2019		2020		2019
Collections		$561		$592		$1,555		$1,636
Write-offs, net of recoveries	1		3		4		11

IPL [Member]

Receivables [Line Items]

Receivables

RECEIVABLES

Note 3(a) Accounts Receivable - Details for accounts receivable included on the balance sheets were as follows (in millions):

	Alliant Energy						IPL						WPL
	September 30, 2020			December 31, 2019			September 30, 2020			December 31, 2019			September 30, 2020			December 31, 2019
Customer		$95			$92			$—			$—			$86			$84
Unbilled utility revenues	62			82			—			—			62			82
Deferred proceeds	201			188			201			188			—			—
Other	54			47			20			16			33			31
Allowance for expected credit losses	(13		)	(7		)	(2		)	(1		)	(11		)	(6		)
		$399			$402			$219			$203			$170			$191

Note 3(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. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. As of September 30, 2020, IPL had $109 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 nine months ended September 30 were as follows (in millions):

	Three Months				Nine Months
	2020		2019		2020		2019
Maximum outstanding aggregate cash proceeds		$1		$103		$96		$108
Average outstanding aggregate cash proceeds	1		45		12		43

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

	September 30, 2020		December 31, 2019
Customer accounts receivable		$148		$125
Unbilled utility revenues	67		95
Other receivables	—		1
Receivables sold to third party	215		221
Less: cash proceeds	1		27
Deferred proceeds	214		194
Less: allowance for expected credit losses	13		6
Fair value of deferred proceeds		$201		$188

As of September 30, 2020, outstanding receivables past due under the Receivables Agreement were $27 million. Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and nine months ended September 30 were as follows (in millions):

	Three Months				Nine Months
	2020		2019		2020		2019
Collections		$561		$592		$1,555		$1,636
Write-offs, net of recoveries	1		3		4		11

WPL [Member]

Receivables [Line Items]

Receivables

RECEIVABLES

Note 3(a) Accounts Receivable - Details for accounts receivable included on the balance sheets were as follows (in millions):

	Alliant Energy						IPL						WPL
	September 30, 2020			December 31, 2019			September 30, 2020			December 31, 2019			September 30, 2020			December 31, 2019
Customer		$95			$92			$—			$—			$86			$84
Unbilled utility revenues	62			82			—			—			62			82
Deferred proceeds	201			188			201			188			—			—
Other	54			47			20			16			33			31
Allowance for expected credit losses	(13		)	(7		)	(2		)	(1		)	(11		)	(6		)
		$399			$402			$219			$203			$170			$191

XML

Investments

9 Months Ended

Sep. 30, 2020

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 nine months ended September 30 was as follows (in millions):

	Three Months						Nine Months
	2020			2019			2020			2019
ATC Holdings		($11	)		($11	)		($36	)		($30	)
Non-utility wind farm in Oklahoma	(2		)	—			(6		)	(3		)
Other	(2		)	(1		)	(4		)	(2		)
		($15	)		($12	)		($46	)		($35	)

XML

Common Equity

9 Months Ended

Sep. 30, 2020

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, 2020	245,022,800
Equity forward agreements	4,275,127
Shareowner Direct Plan	364,531
Equity-based compensation plans	98,205
Shares outstanding, September 30, 2020	249,760,663

Equity Forward Agreements - In November 2019, Alliant Energy entered into forward sale agreements with a counterparty in connection with a public offering of 4,275,127 shares of Alliant Energy common stock. The initial forward sale price of $52.235 per share was subject to daily adjustment based on a floating interest rate factor, and decreased by other fixed amounts specified in the forward sale agreements. In the first quarter of 2020, Alliant Energy settled $222 million under the forward sale agreements by delivering 4,275,127 shares of newly issued Alliant Energy common stock at a weighted average forward sale price of $51.98 per share. Alliant Energy used the net proceeds from the settlements for general corporate purposes.

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			Cumulative
			Additional					Other			Deferred			Preferred
	Common		Paid-In		Retained			Comprehensive			Compensation			Stock		Total
	Stock		Capital		Earnings			Income (Loss)			Trust			of IPL		Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$2		$2,683		$2,874			($1	)		($10	)		$200		$5,748
Net income attributable to Alliant Energy common shareowners					246											246
Common stock dividends ($0.38 per share)					(94		)									(94		)
Shareowner Direct Plan issuances			6													6
Equity-based compensation plans and other			4								(1		)			3
Ending balance, September 30, 2020		$2		$2,693		$3,026			($1	)		($11	)		$200		$5,909
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$2		$2,109		$2,598			$1			($10	)		$200		$4,900
Net income attributable to Alliant Energy common shareowners					226											226
Common stock dividends ($0.355 per share)					(85		)									(85		)
Equity forward settlements and Shareowner Direct Plan issuances			125													125
Equity-based compensation plans and other			3													3
Ending balance, September 30, 2019		$2		$2,237		$2,739			$1			($10	)		$200		$5,169

Alliant Energy	Total Alliant Energy Common Equity
								Accumulated			Shares in			Cumulative
			Additional					Other			Deferred			Preferred
	Common		Paid-In		Retained			Comprehensive			Compensation			Stock		Total
	Stock		Capital		Earnings			Income (Loss)			Trust			of IPL		Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$2		$2,446		$2,766			$1			($10	)		$200		$5,405
Net income attributable to Alliant Energy common shareowners					550											550
Common stock dividends ($1.14 per share)					(281		)									(281		)
Equity forward settlements and Shareowner Direct Plan issuances			241													241
Equity-based compensation plans and other			6								(1		)			5
Adoption of new accounting standard, net of tax (refer to Note 1(d))					(9		)									(9		)
Other comprehensive loss, net of tax								(2		)						(2		)
Ending balance, September 30, 2020		$2		$2,693		$3,026			($1	)		($11	)		$200		$5,909
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$2		$2,046		$2,546			$2			($10	)		$200		$4,786
Net income attributable to Alliant Energy common shareowners					446											446
Common stock dividends ($1.065 per share)					(253		)									(253		)
Equity forward settlements and Shareowner Direct Plan issuances			185													185
Equity-based compensation plans and other			6													6
Other comprehensive loss, net of tax								(1		)						(1		)
Ending balance, September 30, 2019		$2		$2,237		$2,739			$1			($10	)		$200		$5,169

IPL	Total IPL Common Equity
			Additional					Cumulative
	Common		Paid-In		Retained			Preferred		Total
	Stock		Capital		Earnings			Stock		Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$33		$2,523		$915			$200		$3,671
Net income available for common stock					148					148
Common stock dividends					(59		)			(59		)
Capital contributions from parent			170							170
Ending balance, September 30, 2020		$33		$2,693		$1,004			$200		$3,930
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$33		$2,323		$789			$200		$3,345
Net income available for common stock					141					141
Common stock dividends					(42		)			(42		)
Ending balance, September 30, 2019		$33		$2,323		$888			$200		$3,444

IPL	Total IPL Common Equity
			Additional					Cumulative
	Common		Paid-In		Retained			Preferred		Total
	Stock		Capital		Earnings			Stock		Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$33		$2,348		$891			$200		$3,472
Net income available for common stock					290					290
Common stock dividends					(177		)			(177		)
Capital contributions from parent			345							345
Ending balance, September 30, 2020		$33		$2,693		$1,004			$200		$3,930
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$33		$2,223		$775			$200		$3,231
Net income available for common stock					239					239
Common stock dividends					(126		)			(126		)
Capital contributions from parent			100							100
Ending balance, September 30, 2019		$33		$2,323		$888			$200		$3,444

WPL			Additional					Total
	Common		Paid-In		Retained			Common
	Stock		Capital		Earnings			Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$66		$1,459		$927			$2,452
Net income					73			73
Common stock dividends					(43		)	(43		)
Ending balance, September 30, 2020		$66		$1,459		$957			$2,482
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$66		$1,309		$810			$2,185
Net income					76			76
Common stock dividends					(36		)	(36		)
Capital contributions from parent			100					100
Ending balance, September 30, 2019		$66		$1,409		$850			$2,325

WPL			Additional					Total
	Common		Paid-In		Retained			Common
	Stock		Capital		Earnings			Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$66		$1,434		$864			$2,364
Net income					220			220
Common stock dividends					(127		)	(127		)
Capital contributions from parent			25					25
Ending balance, September 30, 2020		$66		$1,459		$957			$2,482
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$66		$1,309		$775			$2,150
Net income					183			183
Common stock dividends					(108		)	(108		)
Capital contributions from parent			100					100
Ending balance, September 30, 2019		$66		$1,409		$850			$2,325

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, 2020	245,022,800
Equity forward agreements	4,275,127
Shareowner Direct Plan	364,531
Equity-based compensation plans	98,205
Shares outstanding, September 30, 2020	249,760,663

Equity Forward Agreements - In November 2019, Alliant Energy entered into forward sale agreements with a counterparty in connection with a public offering of 4,275,127 shares of Alliant Energy common stock. The initial forward sale price of $52.235 per share was subject to daily adjustment based on a floating interest rate factor, and decreased by other fixed amounts specified in the forward sale agreements. In the first quarter of 2020, Alliant Energy settled $222 million under the forward sale agreements by delivering 4,275,127 shares of newly issued Alliant Energy common stock at a weighted average forward sale price of $51.98 per share. Alliant Energy used the net proceeds from the settlements for general corporate purposes.

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			Cumulative
			Additional					Other			Deferred			Preferred
	Common		Paid-In		Retained			Comprehensive			Compensation			Stock		Total
	Stock		Capital		Earnings			Income (Loss)			Trust			of IPL		Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$2		$2,683		$2,874			($1	)		($10	)		$200		$5,748
Net income attributable to Alliant Energy common shareowners					246											246
Common stock dividends ($0.38 per share)					(94		)									(94		)
Shareowner Direct Plan issuances			6													6
Equity-based compensation plans and other			4								(1		)			3
Ending balance, September 30, 2020		$2		$2,693		$3,026			($1	)		($11	)		$200		$5,909
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$2		$2,109		$2,598			$1			($10	)		$200		$4,900
Net income attributable to Alliant Energy common shareowners					226											226
Common stock dividends ($0.355 per share)					(85		)									(85		)
Equity forward settlements and Shareowner Direct Plan issuances			125													125
Equity-based compensation plans and other			3													3
Ending balance, September 30, 2019		$2		$2,237		$2,739			$1			($10	)		$200		$5,169

Alliant Energy	Total Alliant Energy Common Equity
								Accumulated			Shares in			Cumulative
			Additional					Other			Deferred			Preferred
	Common		Paid-In		Retained			Comprehensive			Compensation			Stock		Total
	Stock		Capital		Earnings			Income (Loss)			Trust			of IPL		Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$2		$2,446		$2,766			$1			($10	)		$200		$5,405
Net income attributable to Alliant Energy common shareowners					550											550
Common stock dividends ($1.14 per share)					(281		)									(281		)
Equity forward settlements and Shareowner Direct Plan issuances			241													241
Equity-based compensation plans and other			6								(1		)			5
Adoption of new accounting standard, net of tax (refer to Note 1(d))					(9		)									(9		)
Other comprehensive loss, net of tax								(2		)						(2		)
Ending balance, September 30, 2020		$2		$2,693		$3,026			($1	)		($11	)		$200		$5,909
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$2		$2,046		$2,546			$2			($10	)		$200		$4,786
Net income attributable to Alliant Energy common shareowners					446											446
Common stock dividends ($1.065 per share)					(253		)									(253		)
Equity forward settlements and Shareowner Direct Plan issuances			185													185
Equity-based compensation plans and other			6													6
Other comprehensive loss, net of tax								(1		)						(1		)
Ending balance, September 30, 2019		$2		$2,237		$2,739			$1			($10	)		$200		$5,169

IPL	Total IPL Common Equity
			Additional					Cumulative
	Common		Paid-In		Retained			Preferred		Total
	Stock		Capital		Earnings			Stock		Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$33		$2,523		$915			$200		$3,671
Net income available for common stock					148					148
Common stock dividends					(59		)			(59		)
Capital contributions from parent			170							170
Ending balance, September 30, 2020		$33		$2,693		$1,004			$200		$3,930
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$33		$2,323		$789			$200		$3,345
Net income available for common stock					141					141
Common stock dividends					(42		)			(42		)
Ending balance, September 30, 2019		$33		$2,323		$888			$200		$3,444

IPL	Total IPL Common Equity
			Additional					Cumulative
	Common		Paid-In		Retained			Preferred		Total
	Stock		Capital		Earnings			Stock		Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$33		$2,348		$891			$200		$3,472
Net income available for common stock					290					290
Common stock dividends					(177		)			(177		)
Capital contributions from parent			345							345
Ending balance, September 30, 2020		$33		$2,693		$1,004			$200		$3,930
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$33		$2,223		$775			$200		$3,231
Net income available for common stock					239					239
Common stock dividends					(126		)			(126		)
Capital contributions from parent			100							100
Ending balance, September 30, 2019		$33		$2,323		$888			$200		$3,444

WPL			Additional					Total
	Common		Paid-In		Retained			Common
	Stock		Capital		Earnings			Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$66		$1,459		$927			$2,452
Net income					73			73
Common stock dividends					(43		)	(43		)
Ending balance, September 30, 2020		$66		$1,459		$957			$2,482
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$66		$1,309		$810			$2,185
Net income					76			76
Common stock dividends					(36		)	(36		)
Capital contributions from parent			100					100
Ending balance, September 30, 2019		$66		$1,409		$850			$2,325

WPL			Additional					Total
	Common		Paid-In		Retained			Common
	Stock		Capital		Earnings			Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$66		$1,434		$864			$2,364
Net income					220			220
Common stock dividends					(127		)	(127		)
Capital contributions from parent			25					25
Ending balance, September 30, 2020		$66		$1,459		$957			$2,482
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$66		$1,309		$775			$2,150
Net income					183			183
Common stock dividends					(108		)	(108		)
Capital contributions from parent			100					100
Ending balance, September 30, 2019		$66		$1,409		$850			$2,325

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, 2020	245,022,800
Equity forward agreements	4,275,127
Shareowner Direct Plan	364,531
Equity-based compensation plans	98,205
Shares outstanding, September 30, 2020	249,760,663

Equity Forward Agreements - In November 2019, Alliant Energy entered into forward sale agreements with a counterparty in connection with a public offering of 4,275,127 shares of Alliant Energy common stock. The initial forward sale price of $52.235 per share was subject to daily adjustment based on a floating interest rate factor, and decreased by other fixed amounts specified in the forward sale agreements. In the first quarter of 2020, Alliant Energy settled $222 million under the forward sale agreements by delivering 4,275,127 shares of newly issued Alliant Energy common stock at a weighted average forward sale price of $51.98 per share. Alliant Energy used the net proceeds from the settlements for general corporate purposes.

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			Cumulative
			Additional					Other			Deferred			Preferred
	Common		Paid-In		Retained			Comprehensive			Compensation			Stock		Total
	Stock		Capital		Earnings			Income (Loss)			Trust			of IPL		Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$2		$2,683		$2,874			($1	)		($10	)		$200		$5,748
Net income attributable to Alliant Energy common shareowners					246											246
Common stock dividends ($0.38 per share)					(94		)									(94		)
Shareowner Direct Plan issuances			6													6
Equity-based compensation plans and other			4								(1		)			3
Ending balance, September 30, 2020		$2		$2,693		$3,026			($1	)		($11	)		$200		$5,909
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$2		$2,109		$2,598			$1			($10	)		$200		$4,900
Net income attributable to Alliant Energy common shareowners					226											226
Common stock dividends ($0.355 per share)					(85		)									(85		)
Equity forward settlements and Shareowner Direct Plan issuances			125													125
Equity-based compensation plans and other			3													3
Ending balance, September 30, 2019		$2		$2,237		$2,739			$1			($10	)		$200		$5,169

Alliant Energy	Total Alliant Energy Common Equity
								Accumulated			Shares in			Cumulative
			Additional					Other			Deferred			Preferred
	Common		Paid-In		Retained			Comprehensive			Compensation			Stock		Total
	Stock		Capital		Earnings			Income (Loss)			Trust			of IPL		Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$2		$2,446		$2,766			$1			($10	)		$200		$5,405
Net income attributable to Alliant Energy common shareowners					550											550
Common stock dividends ($1.14 per share)					(281		)									(281		)
Equity forward settlements and Shareowner Direct Plan issuances			241													241
Equity-based compensation plans and other			6								(1		)			5
Adoption of new accounting standard, net of tax (refer to Note 1(d))					(9		)									(9		)
Other comprehensive loss, net of tax								(2		)						(2		)
Ending balance, September 30, 2020		$2		$2,693		$3,026			($1	)		($11	)		$200		$5,909
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$2		$2,046		$2,546			$2			($10	)		$200		$4,786
Net income attributable to Alliant Energy common shareowners					446											446
Common stock dividends ($1.065 per share)					(253		)									(253		)
Equity forward settlements and Shareowner Direct Plan issuances			185													185
Equity-based compensation plans and other			6													6
Other comprehensive loss, net of tax								(1		)						(1		)
Ending balance, September 30, 2019		$2		$2,237		$2,739			$1			($10	)		$200		$5,169

IPL	Total IPL Common Equity
			Additional					Cumulative
	Common		Paid-In		Retained			Preferred		Total
	Stock		Capital		Earnings			Stock		Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$33		$2,523		$915			$200		$3,671
Net income available for common stock					148					148
Common stock dividends					(59		)			(59		)
Capital contributions from parent			170							170
Ending balance, September 30, 2020		$33		$2,693		$1,004			$200		$3,930
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$33		$2,323		$789			$200		$3,345
Net income available for common stock					141					141
Common stock dividends					(42		)			(42		)
Ending balance, September 30, 2019		$33		$2,323		$888			$200		$3,444

IPL	Total IPL Common Equity
			Additional					Cumulative
	Common		Paid-In		Retained			Preferred		Total
	Stock		Capital		Earnings			Stock		Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$33		$2,348		$891			$200		$3,472
Net income available for common stock					290					290
Common stock dividends					(177		)			(177		)
Capital contributions from parent			345							345
Ending balance, September 30, 2020		$33		$2,693		$1,004			$200		$3,930
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$33		$2,223		$775			$200		$3,231
Net income available for common stock					239					239
Common stock dividends					(126		)			(126		)
Capital contributions from parent			100							100
Ending balance, September 30, 2019		$33		$2,323		$888			$200		$3,444

WPL			Additional					Total
	Common		Paid-In		Retained			Common
	Stock		Capital		Earnings			Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$66		$1,459		$927			$2,452
Net income					73			73
Common stock dividends					(43		)	(43		)
Ending balance, September 30, 2020		$66		$1,459		$957			$2,482
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$66		$1,309		$810			$2,185
Net income					76			76
Common stock dividends					(36		)	(36		)
Capital contributions from parent			100					100
Ending balance, September 30, 2019		$66		$1,409		$850			$2,325

WPL			Additional					Total
	Common		Paid-In		Retained			Common
	Stock		Capital		Earnings			Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$66		$1,434		$864			$2,364
Net income					220			220
Common stock dividends					(127		)	(127		)
Capital contributions from parent			25					25
Ending balance, September 30, 2020		$66		$1,459		$957			$2,482
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$66		$1,309		$775			$2,150
Net income					183			183
Common stock dividends					(108		)	(108		)
Capital contributions from parent			100					100
Ending balance, September 30, 2019		$66		$1,409		$850			$2,325

XML

Debt

9 Months Ended

Sep. 30, 2020

Debt [Line Items]

Debt

DEBT

NOTE 6(a) Short-term Debt - Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, which currently expires in August 2023, classified as short-term debt was as follows (dollars in millions):

September 30, 2020	Alliant Energy	IPL	WPL
Amount outstanding	$422	$—	$139
Weighted average interest rates	0.2%	N/A	0.1%
Available credit facility capacity	$578	$250	$161

	Alliant Energy				IPL				WPL
Three Months Ended September 30	2020		2019		2020		2019		2020		2019
Maximum amount outstanding (based on daily outstanding balances)		$422		$472		$—		$—		$139		$90
Average amount outstanding (based on daily outstanding balances)		$252		$400		$—		$—		$83		$27
Weighted average interest rates	0.2%		2.5%		N/A		N/A		0.2%		2.3%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)		$463		$601		$8		$50		$212		$195
Average amount outstanding (based on daily outstanding balances)		$252		$476		$—		$—		$86		$102
Weighted average interest rates	1.1%		2.6%		0.5%		2.8%		1.2%		2.5%

NOTE 6(b) Long-term Debt - In March 2020, AEF entered into a $300 million variable rate (1% as of September 30, 2020) term loan credit agreement (with Alliant Energy as guarantor) and used the borrowings under this agreement to retire its $300 million variable rate term loan credit agreement that would have expired in April 2020. AEF’s current term loan credit agreement expires in March 2022 and includes substantially the same financial covenants that are included in Alliant Energy’s credit facility agreement.

In April 2020, WPL issued $350 million of 3.65% debentures due 2050. The net proceeds from the issuance were used by WPL to reduce borrowings under the single credit facility and for general corporate purposes. In June 2020, WPL retired its $150 million 4.6% debentures.

In June 2020, IPL issued $400 million of 2.3% senior debentures due 2030. The net proceeds from the issuance were used by IPL to retire its $200 million 3.65% senior debentures that would have matured in September 2020 and for general corporate purposes.

IPL [Member]

Debt [Line Items]

Debt

DEBT

NOTE 6(a) Short-term Debt - Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, which currently expires in August 2023, classified as short-term debt was as follows (dollars in millions):

September 30, 2020	Alliant Energy	IPL	WPL
Amount outstanding	$422	$—	$139
Weighted average interest rates	0.2%	N/A	0.1%
Available credit facility capacity	$578	$250	$161

	Alliant Energy				IPL				WPL
Three Months Ended September 30	2020		2019		2020		2019		2020		2019
Maximum amount outstanding (based on daily outstanding balances)		$422		$472		$—		$—		$139		$90
Average amount outstanding (based on daily outstanding balances)		$252		$400		$—		$—		$83		$27
Weighted average interest rates	0.2%		2.5%		N/A		N/A		0.2%		2.3%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)		$463		$601		$8		$50		$212		$195
Average amount outstanding (based on daily outstanding balances)		$252		$476		$—		$—		$86		$102
Weighted average interest rates	1.1%		2.6%		0.5%		2.8%		1.2%		2.5%

NOTE 6(b) Long-term Debt - In March 2020, AEF entered into a $300 million variable rate (1% as of September 30, 2020) term loan credit agreement (with Alliant Energy as guarantor) and used the borrowings under this agreement to retire its $300 million variable rate term loan credit agreement that would have expired in April 2020. AEF’s current term loan credit agreement expires in March 2022 and includes substantially the same financial covenants that are included in Alliant Energy’s credit facility agreement.

In April 2020, WPL issued $350 million of 3.65% debentures due 2050. The net proceeds from the issuance were used by WPL to reduce borrowings under the single credit facility and for general corporate purposes. In June 2020, WPL retired its $150 million 4.6% debentures.

In June 2020, IPL issued $400 million of 2.3% senior debentures due 2030. The net proceeds from the issuance were used by IPL to retire its $200 million 3.65% senior debentures that would have matured in September 2020 and for general corporate purposes.

WPL [Member]

Debt [Line Items]

Debt

DEBT

NOTE 6(a) Short-term Debt - Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, which currently expires in August 2023, classified as short-term debt was as follows (dollars in millions):

September 30, 2020	Alliant Energy	IPL	WPL
Amount outstanding	$422	$—	$139
Weighted average interest rates	0.2%	N/A	0.1%
Available credit facility capacity	$578	$250	$161

	Alliant Energy				IPL				WPL
Three Months Ended September 30	2020		2019		2020		2019		2020		2019
Maximum amount outstanding (based on daily outstanding balances)		$422		$472		$—		$—		$139		$90
Average amount outstanding (based on daily outstanding balances)		$252		$400		$—		$—		$83		$27
Weighted average interest rates	0.2%		2.5%		N/A		N/A		0.2%		2.3%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)		$463		$601		$8		$50		$212		$195
Average amount outstanding (based on daily outstanding balances)		$252		$476		$—		$—		$86		$102
Weighted average interest rates	1.1%		2.6%		0.5%		2.8%		1.2%		2.5%

NOTE 6(b) Long-term Debt - In March 2020, AEF entered into a $300 million variable rate (1% as of September 30, 2020) term loan credit agreement (with Alliant Energy as guarantor) and used the borrowings under this agreement to retire its $300 million variable rate term loan credit agreement that would have expired in April 2020. AEF’s current term loan credit agreement expires in March 2022 and includes substantially the same financial covenants that are included in Alliant Energy’s credit facility agreement.

In April 2020, WPL issued $350 million of 3.65% debentures due 2050. The net proceeds from the issuance were used by WPL to reduce borrowings under the single credit facility and for general corporate purposes. In June 2020, WPL retired its $150 million 4.6% debentures.

In June 2020, IPL issued $400 million of 2.3% senior debentures due 2030. The net proceeds from the issuance were used by IPL to retire its $200 million 3.65% senior debentures that would have matured in September 2020 and for general corporate purposes.

XML

Revenues

9 Months Ended

Sep. 30, 2020

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 September 30	2020		2019		2020		2019		2020		2019
Electric Utility:
Retail - residential		$328		$332		$189		$196		$139		$136
Retail - commercial	210		231		142		158		68		73
Retail - industrial	241		264		149		158		92		106
Wholesale	47		50		17		18		30		32
Bulk power and other	26		39		22		31		4		8
Total Electric Utility	852		916		519		561		333		355
Gas Utility:
Retail - residential	22		20		12		12		10		8
Retail - commercial	10		10		6		6		4		4
Retail - industrial	2		3		1		2		1		1
Transportation/other	8		9		5		5		3		4
Total Gas Utility	42		42		24		25		18		17
Other Utility:
Steam	8		9		8		9		—		—
Other utility	2		2		2		2		—		—
Total Other Utility	10		11		10		11		—		—
Non-Utility and Other:
Transportation and other	16		21		—		—		—		—
Total Non-Utility and Other	16		21		—		—		—		—
Total revenues		$920		$990		$553		$597		$351		$372

	Alliant Energy				IPL				WPL
Nine Months Ended September 30	2020		2019		2020		2019		2020		2019
Electric Utility:
Retail - residential		$845		$840		$472		$470		$373		$370
Retail - commercial	556		583		371		386		185		197
Retail - industrial	648		686		384		392		264		294
Wholesale	127		137		44		49		83		88
Bulk power and other	81		104		61		76		20		28
Total Electric Utility	2,257		2,350		1,332		1,373		925		977
Gas Utility:
Retail - residential	146		187		79		109		67		78
Retail - commercial	70		90		38		50		32		40
Retail - industrial	8		10		5		7		3		3
Transportation/other	29		36		19		22		10		14
Total Gas Utility	253		323		141		188		112		135
Other Utility:
Steam	27		27		27		27		—		—
Other utility	5		6		4		5		1		1
Total Other Utility	32		33		31		32		1		1
Non-Utility and Other:
Transportation and other	57		62		—		—		—		—
Total Non-Utility and Other	57		62		—		—		—		—
Total revenues		$2,599		$2,768		$1,504		$1,593		$1,038		$1,113

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 September 30	2020		2019		2020		2019		2020		2019
Electric Utility:
Retail - residential		$328		$332		$189		$196		$139		$136
Retail - commercial	210		231		142		158		68		73
Retail - industrial	241		264		149		158		92		106
Wholesale	47		50		17		18		30		32
Bulk power and other	26		39		22		31		4		8
Total Electric Utility	852		916		519		561		333		355
Gas Utility:
Retail - residential	22		20		12		12		10		8
Retail - commercial	10		10		6		6		4		4
Retail - industrial	2		3		1		2		1		1
Transportation/other	8		9		5		5		3		4
Total Gas Utility	42		42		24		25		18		17
Other Utility:
Steam	8		9		8		9		—		—
Other utility	2		2		2		2		—		—
Total Other Utility	10		11		10		11		—		—
Non-Utility and Other:
Transportation and other	16		21		—		—		—		—
Total Non-Utility and Other	16		21		—		—		—		—
Total revenues		$920		$990		$553		$597		$351		$372

	Alliant Energy				IPL				WPL
Nine Months Ended September 30	2020		2019		2020		2019		2020		2019
Electric Utility:
Retail - residential		$845		$840		$472		$470		$373		$370
Retail - commercial	556		583		371		386		185		197
Retail - industrial	648		686		384		392		264		294
Wholesale	127		137		44		49		83		88
Bulk power and other	81		104		61		76		20		28
Total Electric Utility	2,257		2,350		1,332		1,373		925		977
Gas Utility:
Retail - residential	146		187		79		109		67		78
Retail - commercial	70		90		38		50		32		40
Retail - industrial	8		10		5		7		3		3
Transportation/other	29		36		19		22		10		14
Total Gas Utility	253		323		141		188		112		135
Other Utility:
Steam	27		27		27		27		—		—
Other utility	5		6		4		5		1		1
Total Other Utility	32		33		31		32		1		1
Non-Utility and Other:
Transportation and other	57		62		—		—		—		—
Total Non-Utility and Other	57		62		—		—		—		—
Total revenues		$2,599		$2,768		$1,504		$1,593		$1,038		$1,113

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 September 30	2020		2019		2020		2019		2020		2019
Electric Utility:
Retail - residential		$328		$332		$189		$196		$139		$136
Retail - commercial	210		231		142		158		68		73
Retail - industrial	241		264		149		158		92		106
Wholesale	47		50		17		18		30		32
Bulk power and other	26		39		22		31		4		8
Total Electric Utility	852		916		519		561		333		355
Gas Utility:
Retail - residential	22		20		12		12		10		8
Retail - commercial	10		10		6		6		4		4
Retail - industrial	2		3		1		2		1		1
Transportation/other	8		9		5		5		3		4
Total Gas Utility	42		42		24		25		18		17
Other Utility:
Steam	8		9		8		9		—		—
Other utility	2		2		2		2		—		—
Total Other Utility	10		11		10		11		—		—
Non-Utility and Other:
Transportation and other	16		21		—		—		—		—
Total Non-Utility and Other	16		21		—		—		—		—
Total revenues		$920		$990		$553		$597		$351		$372

	Alliant Energy				IPL				WPL
Nine Months Ended September 30	2020		2019		2020		2019		2020		2019
Electric Utility:
Retail - residential		$845		$840		$472		$470		$373		$370
Retail - commercial	556		583		371		386		185		197
Retail - industrial	648		686		384		392		264		294
Wholesale	127		137		44		49		83		88
Bulk power and other	81		104		61		76		20		28
Total Electric Utility	2,257		2,350		1,332		1,373		925		977
Gas Utility:
Retail - residential	146		187		79		109		67		78
Retail - commercial	70		90		38		50		32		40
Retail - industrial	8		10		5		7		3		3
Transportation/other	29		36		19		22		10		14
Total Gas Utility	253		323		141		188		112		135
Other Utility:
Steam	27		27		27		27		—		—
Other utility	5		6		4		5		1		1
Total Other Utility	32		33		31		32		1		1
Non-Utility and Other:
Transportation and other	57		62		—		—		—		—
Total Non-Utility and Other	57		62		—		—		—		—
Total revenues		$2,599		$2,768		$1,504		$1,593		$1,038		$1,113

XML

Income Taxes

9 Months Ended

Sep. 30, 2020

Income Taxes [Line Items]

Income Taxes

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. The decreases in overall effective income tax rates for the three and nine months ended September 30, 2020 compared to the same periods in 2019 were primarily due to increases in production tax credits as a result of increased wind production in 2020 and increased amortization of excess deferred taxes primarily at WPL, which were used to offset increases in WPL’s 2020 increased revenue requirements.

	Alliant Energy				IPL				WPL
	Three Months		Nine Months		Three Months		Nine Months		Three Months		Nine Months
	2020	2019	2020	2019	2020	2019	2020	2019	2020	2019	2020	2019
Overall income tax rate	(9%)	9%	(9%)	10%	(14%)	5%	(14%)	4%	(7%)	18%	(8%)	18%

Deferred Tax Assets and Liabilities -

Carryforwards - At September 30, 2020, carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy		IPL		WPL
Federal net operating losses	2037		$371		$343		$3
State net operating losses	2020-2040	623		10		2
Federal tax credits	2022-2040	446		252		173

IPL [Member]

Income Taxes [Line Items]

Income Taxes

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. The decreases in overall effective income tax rates for the three and nine months ended September 30, 2020 compared to the same periods in 2019 were primarily due to increases in production tax credits as a result of increased wind production in 2020 and increased amortization of excess deferred taxes primarily at WPL, which were used to offset increases in WPL’s 2020 increased revenue requirements.

	Alliant Energy				IPL				WPL
	Three Months		Nine Months		Three Months		Nine Months		Three Months		Nine Months
	2020	2019	2020	2019	2020	2019	2020	2019	2020	2019	2020	2019
Overall income tax rate	(9%)	9%	(9%)	10%	(14%)	5%	(14%)	4%	(7%)	18%	(8%)	18%

Deferred Tax Assets and Liabilities -

Carryforwards - At September 30, 2020, carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy		IPL		WPL
Federal net operating losses	2037		$371		$343		$3
State net operating losses	2020-2040	623		10		2
Federal tax credits	2022-2040	446		252		173

WPL [Member]

Income Taxes [Line Items]

Income Taxes

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. The decreases in overall effective income tax rates for the three and nine months ended September 30, 2020 compared to the same periods in 2019 were primarily due to increases in production tax credits as a result of increased wind production in 2020 and increased amortization of excess deferred taxes primarily at WPL, which were used to offset increases in WPL’s 2020 increased revenue requirements.

	Alliant Energy				IPL				WPL
	Three Months		Nine Months		Three Months		Nine Months		Three Months		Nine Months
	2020	2019	2020	2019	2020	2019	2020	2019	2020	2019	2020	2019
Overall income tax rate	(9%)	9%	(9%)	10%	(14%)	5%	(14%)	4%	(7%)	18%	(8%)	18%

Deferred Tax Assets and Liabilities -

Carryforwards - At September 30, 2020, carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy		IPL		WPL
Federal net operating losses	2037		$371		$343		$3
State net operating losses	2020-2040	623		10		2
Federal tax credits	2022-2040	446		252		173

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Benefit Plans

9 Months Ended

Sep. 30, 2020

Benefit Plans

BENEFIT PLANS

NOTE 9(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 nine months ended September 30 are included below (in millions). For IPL and WPL, amounts represent those 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						Nine Months						Three Months						Nine Months
Alliant Energy	2020			2019			2020			2019			2020			2019			2020			2019
Service cost		$3			$2			$8			$7			$1			$1			$3			$3
Interest cost	10			13			32			37			2			2			5			6
Expected return on plan assets	(17		)	(15		)	(52		)	(45		)	(1		)	(1		)	(4		)	(4		)
Amortization of actuarial loss	9			9			26			27			—			1			2			2
Settlement losses (a)	—			—			4			—			—			—			—			—
		$5			$9			$18			$26			$2			$3			$6			$7

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
IPL	2020			2019			2020			2019			2020			2019			2020			2019
Service cost		$2			$1			$5			$4			$—			$—			$1			$1
Interest cost	5			6			15			17			1			1			2			3
Expected return on plan assets	(8		)	(7		)	(24		)	(21		)	(1		)	(1		)	(3		)	(3		)
Amortization of actuarial loss	4			4			11			12			—			1			1			1
		$3			$4			$7			$12			$—			$1			$1			$2

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months					Nine Months
WPL	2020			2019			2020			2019			2020			2019		2020			2019
Service cost		$1			$1			$3			$3			$—			$—		$1			$1
Interest cost	5			5			14			16			1			1		2			3
Expected return on plan assets	(8		)	(6		)	(23		)	(20		)	(1		)	—		(1		)	(1		)
Amortization of actuarial loss	4			4			12			13			1			—		2			1
		$2			$4			$6			$12			$1			$1		$4			$4

(a) Settlement losses related to payments made to retired executives of Alliant Energy.

NOTE 9(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 nine months ended September 30 was as follows (in millions):

	Alliant Energy								IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months				Three Months				Nine Months
	2020		2019		2020		2019		2020		2019		2020		2019		2020		2019		2020		2019
Compensation expense		$5		$8		$10		$16		$3		$4		$6		$9		$2		$3		$4		$6
Income tax benefits	1		2		3		4		1		1		2		2		—		1		1		2

As of September 30, 2020, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $7 million, $4 million and $3 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years.

For the nine months ended September 30, 2020, performance shares, performance restricted stock units and restricted stock units were granted to key employees as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards. As of September 30, 2020, 276,070 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

		Weighted Average
	Grants	Grant Date Fair Value
Performance shares	55,303		$64.04
Performance restricted stock units	55,303	59.47
Restricted stock units	60,284	59.49

IPL [Member]

Benefit Plans

BENEFIT PLANS

NOTE 9(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 nine months ended September 30 are included below (in millions). For IPL and WPL, amounts represent those 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						Nine Months						Three Months						Nine Months
Alliant Energy	2020			2019			2020			2019			2020			2019			2020			2019
Service cost		$3			$2			$8			$7			$1			$1			$3			$3
Interest cost	10			13			32			37			2			2			5			6
Expected return on plan assets	(17		)	(15		)	(52		)	(45		)	(1		)	(1		)	(4		)	(4		)
Amortization of actuarial loss	9			9			26			27			—			1			2			2
Settlement losses (a)	—			—			4			—			—			—			—			—
		$5			$9			$18			$26			$2			$3			$6			$7

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
IPL	2020			2019			2020			2019			2020			2019			2020			2019
Service cost		$2			$1			$5			$4			$—			$—			$1			$1
Interest cost	5			6			15			17			1			1			2			3
Expected return on plan assets	(8		)	(7		)	(24		)	(21		)	(1		)	(1		)	(3		)	(3		)
Amortization of actuarial loss	4			4			11			12			—			1			1			1
		$3			$4			$7			$12			$—			$1			$1			$2

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months					Nine Months
WPL	2020			2019			2020			2019			2020			2019		2020			2019
Service cost		$1			$1			$3			$3			$—			$—		$1			$1
Interest cost	5			5			14			16			1			1		2			3
Expected return on plan assets	(8		)	(6		)	(23		)	(20		)	(1		)	—		(1		)	(1		)
Amortization of actuarial loss	4			4			12			13			1			—		2			1
		$2			$4			$6			$12			$1			$1		$4			$4

(a) Settlement losses related to payments made to retired executives of Alliant Energy.

NOTE 9(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 nine months ended September 30 was as follows (in millions):

	Alliant Energy								IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months				Three Months				Nine Months
	2020		2019		2020		2019		2020		2019		2020		2019		2020		2019		2020		2019
Compensation expense		$5		$8		$10		$16		$3		$4		$6		$9		$2		$3		$4		$6
Income tax benefits	1		2		3		4		1		1		2		2		—		1		1		2

As of September 30, 2020, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $7 million, $4 million and $3 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years.

For the nine months ended September 30, 2020, performance shares, performance restricted stock units and restricted stock units were granted to key employees as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards. As of September 30, 2020, 276,070 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

		Weighted Average
	Grants	Grant Date Fair Value
Performance shares	55,303		$64.04
Performance restricted stock units	55,303	59.47
Restricted stock units	60,284	59.49

WPL [Member]

Benefit Plans

BENEFIT PLANS

NOTE 9(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 nine months ended September 30 are included below (in millions). For IPL and WPL, amounts represent those 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						Nine Months						Three Months						Nine Months
Alliant Energy	2020			2019			2020			2019			2020			2019			2020			2019
Service cost		$3			$2			$8			$7			$1			$1			$3			$3
Interest cost	10			13			32			37			2			2			5			6
Expected return on plan assets	(17		)	(15		)	(52		)	(45		)	(1		)	(1		)	(4		)	(4		)
Amortization of actuarial loss	9			9			26			27			—			1			2			2
Settlement losses (a)	—			—			4			—			—			—			—			—
		$5			$9			$18			$26			$2			$3			$6			$7

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
IPL	2020			2019			2020			2019			2020			2019			2020			2019
Service cost		$2			$1			$5			$4			$—			$—			$1			$1
Interest cost	5			6			15			17			1			1			2			3
Expected return on plan assets	(8		)	(7		)	(24		)	(21		)	(1		)	(1		)	(3		)	(3		)
Amortization of actuarial loss	4			4			11			12			—			1			1			1
		$3			$4			$7			$12			$—			$1			$1			$2

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months					Nine Months
WPL	2020			2019			2020			2019			2020			2019		2020			2019
Service cost		$1			$1			$3			$3			$—			$—		$1			$1
Interest cost	5			5			14			16			1			1		2			3
Expected return on plan assets	(8		)	(6		)	(23		)	(20		)	(1		)	—		(1		)	(1		)
Amortization of actuarial loss	4			4			12			13			1			—		2			1
		$2			$4			$6			$12			$1			$1		$4			$4

(a) Settlement losses related to payments made to retired executives of Alliant Energy.

NOTE 9(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 nine months ended September 30 was as follows (in millions):

	Alliant Energy								IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months				Three Months				Nine Months
	2020		2019		2020		2019		2020		2019		2020		2019		2020		2019		2020		2019
Compensation expense		$5		$8		$10		$16		$3		$4		$6		$9		$2		$3		$4		$6
Income tax benefits	1		2		3		4		1		1		2		2		—		1		1		2

As of September 30, 2020, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $7 million, $4 million and $3 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years.

For the nine months ended September 30, 2020, performance shares, performance restricted stock units and restricted stock units were granted to key employees as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards. As of September 30, 2020, 276,070 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

		Weighted Average
	Grants	Grant Date Fair Value
Performance shares	55,303		$64.04
Performance restricted stock units	55,303	59.47
Restricted stock units	60,284	59.49

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Asset Retirement Obligations

9 Months Ended

Sep. 30, 2020

Asset Retirement Obligations [Line Items]

Asset Retirement Obligations

ASSET RETIREMENT OBLIGATIONS

A reconciliation of the changes in asset retirement obligations associated with long-lived assets for the nine months ended September 30, 2020 is as follows (in millions):

	Alliant Energy			IPL
Balance, January 1		$196			$134
Revisions in estimated cash flows	1			—
Liabilities settled	(7		)	(5		)
Liabilities incurred (a)	38			38
Accretion expense	5			4
Balance, September 30		$233			$171

(a)

During the nine months ended September 30, 2020, Alliant Energy and IPL recognized additional asset retirement obligations related to IPL’s newly constructed Whispering Willow North, Golden Plains and Richland wind sites. The increases in asset retirement obligations resulted in corresponding increases in property, plant and equipment, net on the respective balance sheets.

IPL [Member]

Asset Retirement Obligations [Line Items]

Asset Retirement Obligations

ASSET RETIREMENT OBLIGATIONS

A reconciliation of the changes in asset retirement obligations associated with long-lived assets for the nine months ended September 30, 2020 is as follows (in millions):

	Alliant Energy			IPL
Balance, January 1		$196			$134
Revisions in estimated cash flows	1			—
Liabilities settled	(7		)	(5		)
Liabilities incurred (a)	38			38
Accretion expense	5			4
Balance, September 30		$233			$171

(a)

During the nine months ended September 30, 2020, Alliant Energy and IPL recognized additional asset retirement obligations related to IPL’s newly constructed Whispering Willow North, Golden Plains and Richland wind sites. The increases in asset retirement obligations resulted in corresponding increases in property, plant and equipment, net on the respective balance sheets.

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Derivative Instruments

9 Months Ended

Sep. 30, 2020

Derivative Instruments [Line Items]

Derivative Instruments

DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Notional Amounts - As of September 30, 2020, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):

	FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	14,365	2020-2021	218,581	2020-2028	8,151	2020-2023	6,174	2020-2022
IPL	5,401	2020-2021	114,747	2020-2028	3,373	2020-2023	—	—
WPL	8,964	2020-2021	103,834	2020-2027	4,778	2020-2023	6,174	2020-2022

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
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Current derivative assets		$33		$16		$23		$12		$10		$4
Non-current derivative assets	15		11		11		10		4		1
Current derivative liabilities	6		19		2		9		4		10
Non-current derivative liabilities	13		19		6		9		7		10

Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At September 30, 2020 and December 31, 2019, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered.

Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at September 30, 2020 and December 31, 2019. Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement.

IPL [Member]

Derivative Instruments [Line Items]

Derivative Instruments

DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Notional Amounts - As of September 30, 2020, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):

	FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	14,365	2020-2021	218,581	2020-2028	8,151	2020-2023	6,174	2020-2022
IPL	5,401	2020-2021	114,747	2020-2028	3,373	2020-2023	—	—
WPL	8,964	2020-2021	103,834	2020-2027	4,778	2020-2023	6,174	2020-2022

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
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Current derivative assets		$33		$16		$23		$12		$10		$4
Non-current derivative assets	15		11		11		10		4		1
Current derivative liabilities	6		19		2		9		4		10
Non-current derivative liabilities	13		19		6		9		7		10

Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At September 30, 2020 and December 31, 2019, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered.

Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at September 30, 2020 and December 31, 2019. 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 September 30, 2020, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):

	FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	14,365	2020-2021	218,581	2020-2028	8,151	2020-2023	6,174	2020-2022
IPL	5,401	2020-2021	114,747	2020-2028	3,373	2020-2023	—	—
WPL	8,964	2020-2021	103,834	2020-2027	4,778	2020-2023	6,174	2020-2022

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
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Current derivative assets		$33		$16		$23		$12		$10		$4
Non-current derivative assets	15		11		11		10		4		1
Current derivative liabilities	6		19		2		9		4		10
Non-current derivative liabilities	13		19		6		9		7		10

Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At September 30, 2020 and December 31, 2019, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered.

Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at September 30, 2020 and December 31, 2019. Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement.

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Fair Value Measurements

9 Months Ended

Sep. 30, 2020

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	September 30, 2020										December 31, 2019
			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		$183		$183		$—		$—		$183		$5		$5		$—		$—		$5
Derivatives	48		—		17		31		48		27		—		5		22		27
Deferred proceeds	201		—		—		201		201		188		—		—		188		188
Liabilities:
Derivatives	19		—		18		1		19		38		—		37		1		38
Long-term debt (incl. current maturities)	6,581		—		7,849		2		7,851		6,190		—		6,918		2		6,920

IPL	September 30, 2020										December 31, 2019
			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		$183		$183		$—		$—		$183		$5		$5		$—		$—		$5
Derivatives	34		—		7		27		34		22		—		3		19		22
Deferred proceeds	201		—		—		201		201		188		—		—		188		188
Liabilities:
Derivatives	8		—		7		1		8		18		—		17		1		18
Long-term debt (incl. current maturities)	3,344		—		3,987		—		3,987		3,147		—		3,489		—		3,489

WPL	September 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Derivatives		$14		$—		$10		$4		$14		$5		$—		$2		$3		$5
Liabilities:
Derivatives	11		—		11		—		11		20		—		20		—		20
Long-term debt (incl. current maturities)	2,130		—		2,667		—		2,667		1,933		—		2,268		—		2,268

Information for Alliant Energy’s and IPL’s fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions). Such amounts for WPL were not material.

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2020			2019			2020		2019
Beginning balance, July 1		$36			$13			$194		$215
Total net gains included in changes in net assets (realized/unrealized)	—			13			—		—
Transfers out of Level 3	—			(1		)	—		—
Sales	(1		)	—			—		—
Settlements (a)	(5		)	(3		)	7		22
Ending balance, September 30		$30			$22			$201		$237
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 September 30		($1	)		$13			$—		$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2020			2019			2020		2019
Beginning balance, January 1		$21			$12			$188		$119
Total net gains included in changes in net assets (realized/unrealized)	8			7			—		—
Transfers out of Level 3	—			3			—		—
Purchases	14			14			—		—
Sales	(1		)	—			—		—
Settlements (a)	(12		)	(14		)	13		118
Ending balance, September 30		$30			$22			$201		$237
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30		$8			$10			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2020			2019			2020		2019
Beginning balance, July 1		$32			$9			$194		$215
Total net gains (losses) included in changes in net assets (realized/unrealized)	(1		)	12			—		—
Transfers out of Level 3	—			(1		)	—		—
Sales	(1		)	—			—		—
Settlements (a)	(4		)	(2		)	7		22
Ending balance, September 30		$26			$18			$201		$237
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 September 30		($1	)		$12			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2020			2019			2020		2019
Beginning balance, January 1		$18			$9			$188		$119
Total net gains included in changes in net assets (realized/unrealized)	7			9			—		—
Transfers out of Level 3	—			2			—		—
Purchases	11			9			—		—
Sales	(1		)	—			—		—
Settlements (a)	(9		)	(11		)	13		118
Ending balance, September 30		$26			$18			$201		$237
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30		$7			$10			$—		$—

(a) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for doubtful accounts 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 as follows (in millions):

	Alliant Energy				IPL				WPL
	Excluding FTRs		FTRs		Excluding FTRs		FTRs		Excluding FTRs		FTRs
September 30, 2020		$18		$12		$17		$9		$1		$3
December 31, 2019	15		7		14		5		1		2

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	September 30, 2020										December 31, 2019
			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		$183		$183		$—		$—		$183		$5		$5		$—		$—		$5
Derivatives	48		—		17		31		48		27		—		5		22		27
Deferred proceeds	201		—		—		201		201		188		—		—		188		188
Liabilities:
Derivatives	19		—		18		1		19		38		—		37		1		38
Long-term debt (incl. current maturities)	6,581		—		7,849		2		7,851		6,190		—		6,918		2		6,920

IPL	September 30, 2020										December 31, 2019
			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		$183		$183		$—		$—		$183		$5		$5		$—		$—		$5
Derivatives	34		—		7		27		34		22		—		3		19		22
Deferred proceeds	201		—		—		201		201		188		—		—		188		188
Liabilities:
Derivatives	8		—		7		1		8		18		—		17		1		18
Long-term debt (incl. current maturities)	3,344		—		3,987		—		3,987		3,147		—		3,489		—		3,489

WPL	September 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Derivatives		$14		$—		$10		$4		$14		$5		$—		$2		$3		$5
Liabilities:
Derivatives	11		—		11		—		11		20		—		20		—		20
Long-term debt (incl. current maturities)	2,130		—		2,667		—		2,667		1,933		—		2,268		—		2,268

Information for Alliant Energy’s and IPL’s fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions). Such amounts for WPL were not material.

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2020			2019			2020		2019
Beginning balance, July 1		$36			$13			$194		$215
Total net gains included in changes in net assets (realized/unrealized)	—			13			—		—
Transfers out of Level 3	—			(1		)	—		—
Sales	(1		)	—			—		—
Settlements (a)	(5		)	(3		)	7		22
Ending balance, September 30		$30			$22			$201		$237
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 September 30		($1	)		$13			$—		$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2020			2019			2020		2019
Beginning balance, January 1		$21			$12			$188		$119
Total net gains included in changes in net assets (realized/unrealized)	8			7			—		—
Transfers out of Level 3	—			3			—		—
Purchases	14			14			—		—
Sales	(1		)	—			—		—
Settlements (a)	(12		)	(14		)	13		118
Ending balance, September 30		$30			$22			$201		$237
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30		$8			$10			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2020			2019			2020		2019
Beginning balance, July 1		$32			$9			$194		$215
Total net gains (losses) included in changes in net assets (realized/unrealized)	(1		)	12			—		—
Transfers out of Level 3	—			(1		)	—		—
Sales	(1		)	—			—		—
Settlements (a)	(4		)	(2		)	7		22
Ending balance, September 30		$26			$18			$201		$237
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 September 30		($1	)		$12			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2020			2019			2020		2019
Beginning balance, January 1		$18			$9			$188		$119
Total net gains included in changes in net assets (realized/unrealized)	7			9			—		—
Transfers out of Level 3	—			2			—		—
Purchases	11			9			—		—
Sales	(1		)	—			—		—
Settlements (a)	(9		)	(11		)	13		118
Ending balance, September 30		$26			$18			$201		$237
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30		$7			$10			$—		$—

(a) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for doubtful accounts 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 as follows (in millions):

	Alliant Energy				IPL				WPL
	Excluding FTRs		FTRs		Excluding FTRs		FTRs		Excluding FTRs		FTRs
September 30, 2020		$18		$12		$17		$9		$1		$3
December 31, 2019	15		7		14		5		1		2

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	September 30, 2020										December 31, 2019
			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		$183		$183		$—		$—		$183		$5		$5		$—		$—		$5
Derivatives	48		—		17		31		48		27		—		5		22		27
Deferred proceeds	201		—		—		201		201		188		—		—		188		188
Liabilities:
Derivatives	19		—		18		1		19		38		—		37		1		38
Long-term debt (incl. current maturities)	6,581		—		7,849		2		7,851		6,190		—		6,918		2		6,920

IPL	September 30, 2020										December 31, 2019
			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		$183		$183		$—		$—		$183		$5		$5		$—		$—		$5
Derivatives	34		—		7		27		34		22		—		3		19		22
Deferred proceeds	201		—		—		201		201		188		—		—		188		188
Liabilities:
Derivatives	8		—		7		1		8		18		—		17		1		18
Long-term debt (incl. current maturities)	3,344		—		3,987		—		3,987		3,147		—		3,489		—		3,489

WPL	September 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Derivatives		$14		$—		$10		$4		$14		$5		$—		$2		$3		$5
Liabilities:
Derivatives	11		—		11		—		11		20		—		20		—		20
Long-term debt (incl. current maturities)	2,130		—		2,667		—		2,667		1,933		—		2,268		—		2,268

Information for Alliant Energy’s and IPL’s fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions). Such amounts for WPL were not material.

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2020			2019			2020		2019
Beginning balance, July 1		$36			$13			$194		$215
Total net gains included in changes in net assets (realized/unrealized)	—			13			—		—
Transfers out of Level 3	—			(1		)	—		—
Sales	(1		)	—			—		—
Settlements (a)	(5		)	(3		)	7		22
Ending balance, September 30		$30			$22			$201		$237
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 September 30		($1	)		$13			$—		$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2020			2019			2020		2019
Beginning balance, January 1		$21			$12			$188		$119
Total net gains included in changes in net assets (realized/unrealized)	8			7			—		—
Transfers out of Level 3	—			3			—		—
Purchases	14			14			—		—
Sales	(1		)	—			—		—
Settlements (a)	(12		)	(14		)	13		118
Ending balance, September 30		$30			$22			$201		$237
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30		$8			$10			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2020			2019			2020		2019
Beginning balance, July 1		$32			$9			$194		$215
Total net gains (losses) included in changes in net assets (realized/unrealized)	(1		)	12			—		—
Transfers out of Level 3	—			(1		)	—		—
Sales	(1		)	—			—		—
Settlements (a)	(4		)	(2		)	7		22
Ending balance, September 30		$26			$18			$201		$237
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 September 30		($1	)		$12			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2020			2019			2020		2019
Beginning balance, January 1		$18			$9			$188		$119
Total net gains included in changes in net assets (realized/unrealized)	7			9			—		—
Transfers out of Level 3	—			2			—		—
Purchases	11			9			—		—
Sales	(1		)	—			—		—
Settlements (a)	(9		)	(11		)	13		118
Ending balance, September 30		$26			$18			$201		$237
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30		$7			$10			$—		$—

(a) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for doubtful accounts 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 as follows (in millions):

	Alliant Energy				IPL				WPL
	Excluding FTRs		FTRs		Excluding FTRs		FTRs		Excluding FTRs		FTRs
September 30, 2020		$18		$12		$17		$9		$1		$3
December 31, 2019	15		7		14		5		1		2

XML

Commitments And Contingencies

9 Months Ended

Sep. 30, 2020

Commitments and Contingencies Disclosure

COMMITMENTS AND CONTINGENCIES

NOTE 13(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects. WPL’s projects include the expansion of solar and wind generation and its gas distribution system in Western Wisconsin. At September 30, 2020, Alliant Energy’s and WPL’s minimum future commitments for these projects were $21 million and $18 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 September 30, 2020, related minimum future commitments were as follows (in millions):

	Alliant Energy		IPL		WPL
Natural gas		$983		$508		$475
Coal (a)	125		70		55
Other (b)	111		49		31
		$1,219		$627		$561

(a) Corporate Services has historically entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. Such commitments were assigned to IPL and WPL based on information available as of September 30, 2020 regarding expected future usage, which is subject to change.

(b) Includes individual commitments incurred during the normal course of business that exceeded $1 million at September 30, 2020.

Refer to Note 2 for discussion of an amendment to shorten the term of the DAEC PPA, which resulted in IPL making a buyout payment in September 2020.

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 September 30, 2020, the currently known partnership obligations for the abandonment obligations are estimated at $68 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 $68 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, the new credit loss accounting standard adopted on January 1, 2020 requires recognition of a liability for expected credit losses related to the contingent obligations that are in the scope of these guarantees. With the adoption of this standard, Alliant Energy recorded a pre-tax $12 million cumulative effect adjustment to decrease the opening balance of retained earnings as of January 1, 2020.

Whiting Petroleum’s creditworthiness deteriorated in the first quarter of 2020, likely from significantly depressed oil and gas prices and general market conditions, and as a result, the credit loss liability was increased to $20 million in the first quarter of 2020. In April 2020, Whiting Petroleum filed for bankruptcy, and in September 2020, Whiting Petroleum completed its reorganization and emerged from bankruptcy. As a result of Whiting Petroleum’s completed bankruptcy proceedings, as well as additional information regarding the guarantees obtained from the bankruptcy proceedings, the credit loss liability was decreased to $5 million in the third quarter of 2020. The credit loss liability is recorded in “Other liabilities” on Alliant Energy’s balance sheet as of September 30, 2020. For the three and nine months ended September 30, 2020, the pre-tax credit loss adjustments of $15 million and $7 million, respectively, were recorded as reductions in Alliant Energy’s “Other operation and maintenance” expenses.

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 $74 million as of September 30, 2020 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 September 30, 2020 and December 31, 2019.

IPL’s Minnesota Electric Distribution Assets - IPL provided indemnifications associated with the 2015 sale of its Minnesota electric distribution assets for losses resulting from potential breach of IPL’s representations, warranties and obligations under the sale agreement. IPL has not recorded any material liabilities related to these indemnifications as of September 30, 2020 and December 31, 2019. The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expired in October 2020.

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 September 30, 2020, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At September 30, 2020, such amounts for WPL were not material.

	Alliant Energy				IPL
Range of estimated future costs		$12	-	$29		$9	-	$24
Current and non-current environmental liabilities	16				13

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 Burlington by December 31, 2021 and 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 to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: 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) Collective Bargaining Agreements - In August 2020, IPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 204 (Cedar Rapids) expired and a new agreement was reached, which expires August 31, 2024.

NOTE 13(f) MISO Transmission Owner Return on Equity Complaints - A group of MISO cooperative and municipal utilities previously filed complaints with FERC requesting a reduction to the base return on equity used by MISO transmission owners, including ITC Midwest LLC and ATC. The first complaint covered the period from November 12, 2013 through February 11, 2015. In 2017, IPL and WPL received refunds related to the first complaint period, which were subsequently refunded to their retail and wholesale customers. The second complaint covered the period from February 12, 2015 through May 11, 2016. In November 2019, FERC issued an order on the previously filed complaints and reduced the base return on equity used by the MISO transmission owners to 9.88% effective for the first complaint period and subsequent to September 28, 2016. The November 2019 FERC order also dismissed the second complaint; therefore, FERC did not direct refunds to be made for that complaint. In May 2020, FERC issued an order in response to various rehearing requests and increased the base return on equity used by the MISO transmission owners from 9.88% to 10.02% for the first complaint period and subsequent to September 28, 2016, which reduces the refunds originally anticipated to be received by IPL and WPL as a result of FERC’s November 2019 order.

For the nine months ended September 30, 2020, IPL and WPL received $15 million and $5 million, respectively, in refunds related to the FERC orders. In October 2020, FERC extended the time to complete additional refunds to September 2021.

IPL currently expects that all refunds will be returned to its retail electric customers after refund amounts and timing are known and a refund plan is approved by the IUB. WPL proposed to retain the refunds as part of WPL’s application with the PSCW to maintain its current retail electric base rates through the end of 2021. WPL currently expects that any refunds not utilized to maintain base rates would be returned to its customers in WPL’s next retail electric rate review proceeding. 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 CONTINGENCIES

NOTE 13(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects. WPL’s projects include the expansion of solar and wind generation and its gas distribution system in Western Wisconsin. At September 30, 2020, Alliant Energy’s and WPL’s minimum future commitments for these projects were $21 million and $18 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 September 30, 2020, related minimum future commitments were as follows (in millions):

	Alliant Energy		IPL		WPL
Natural gas		$983		$508		$475
Coal (a)	125		70		55
Other (b)	111		49		31
		$1,219		$627		$561

(a) Corporate Services has historically entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. Such commitments were assigned to IPL and WPL based on information available as of September 30, 2020 regarding expected future usage, which is subject to change.

(b) Includes individual commitments incurred during the normal course of business that exceeded $1 million at September 30, 2020.

Refer to Note 2 for discussion of an amendment to shorten the term of the DAEC PPA, which resulted in IPL making a buyout payment in September 2020.

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 September 30, 2020, the currently known partnership obligations for the abandonment obligations are estimated at $68 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 $68 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, the new credit loss accounting standard adopted on January 1, 2020 requires recognition of a liability for expected credit losses related to the contingent obligations that are in the scope of these guarantees. With the adoption of this standard, Alliant Energy recorded a pre-tax $12 million cumulative effect adjustment to decrease the opening balance of retained earnings as of January 1, 2020.

Whiting Petroleum’s creditworthiness deteriorated in the first quarter of 2020, likely from significantly depressed oil and gas prices and general market conditions, and as a result, the credit loss liability was increased to $20 million in the first quarter of 2020. In April 2020, Whiting Petroleum filed for bankruptcy, and in September 2020, Whiting Petroleum completed its reorganization and emerged from bankruptcy. As a result of Whiting Petroleum’s completed bankruptcy proceedings, as well as additional information regarding the guarantees obtained from the bankruptcy proceedings, the credit loss liability was decreased to $5 million in the third quarter of 2020. The credit loss liability is recorded in “Other liabilities” on Alliant Energy’s balance sheet as of September 30, 2020. For the three and nine months ended September 30, 2020, the pre-tax credit loss adjustments of $15 million and $7 million, respectively, were recorded as reductions in Alliant Energy’s “Other operation and maintenance” expenses.

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 $74 million as of September 30, 2020 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 September 30, 2020 and December 31, 2019.

IPL’s Minnesota Electric Distribution Assets - IPL provided indemnifications associated with the 2015 sale of its Minnesota electric distribution assets for losses resulting from potential breach of IPL’s representations, warranties and obligations under the sale agreement. IPL has not recorded any material liabilities related to these indemnifications as of September 30, 2020 and December 31, 2019. The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expired in October 2020.

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 September 30, 2020, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At September 30, 2020, such amounts for WPL were not material.

	Alliant Energy				IPL
Range of estimated future costs		$12	-	$29		$9	-	$24
Current and non-current environmental liabilities	16				13

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 Burlington by December 31, 2021 and 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 to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: 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) Collective Bargaining Agreements - In August 2020, IPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 204 (Cedar Rapids) expired and a new agreement was reached, which expires August 31, 2024.

NOTE 13(f) MISO Transmission Owner Return on Equity Complaints - A group of MISO cooperative and municipal utilities previously filed complaints with FERC requesting a reduction to the base return on equity used by MISO transmission owners, including ITC Midwest LLC and ATC. The first complaint covered the period from November 12, 2013 through February 11, 2015. In 2017, IPL and WPL received refunds related to the first complaint period, which were subsequently refunded to their retail and wholesale customers. The second complaint covered the period from February 12, 2015 through May 11, 2016. In November 2019, FERC issued an order on the previously filed complaints and reduced the base return on equity used by the MISO transmission owners to 9.88% effective for the first complaint period and subsequent to September 28, 2016. The November 2019 FERC order also dismissed the second complaint; therefore, FERC did not direct refunds to be made for that complaint. In May 2020, FERC issued an order in response to various rehearing requests and increased the base return on equity used by the MISO transmission owners from 9.88% to 10.02% for the first complaint period and subsequent to September 28, 2016, which reduces the refunds originally anticipated to be received by IPL and WPL as a result of FERC’s November 2019 order.

For the nine months ended September 30, 2020, IPL and WPL received $15 million and $5 million, respectively, in refunds related to the FERC orders. In October 2020, FERC extended the time to complete additional refunds to September 2021.

IPL currently expects that all refunds will be returned to its retail electric customers after refund amounts and timing are known and a refund plan is approved by the IUB. WPL proposed to retain the refunds as part of WPL’s application with the PSCW to maintain its current retail electric base rates through the end of 2021. WPL currently expects that any refunds not utilized to maintain base rates would be returned to its customers in WPL’s next retail electric rate review proceeding. 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 CONTINGENCIES

NOTE 13(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects. WPL’s projects include the expansion of solar and wind generation and its gas distribution system in Western Wisconsin. At September 30, 2020, Alliant Energy’s and WPL’s minimum future commitments for these projects were $21 million and $18 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 September 30, 2020, related minimum future commitments were as follows (in millions):

	Alliant Energy		IPL		WPL
Natural gas		$983		$508		$475
Coal (a)	125		70		55
Other (b)	111		49		31
		$1,219		$627		$561

(a) Corporate Services has historically entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. Such commitments were assigned to IPL and WPL based on information available as of September 30, 2020 regarding expected future usage, which is subject to change.

(b) Includes individual commitments incurred during the normal course of business that exceeded $1 million at September 30, 2020.

Refer to Note 2 for discussion of an amendment to shorten the term of the DAEC PPA, which resulted in IPL making a buyout payment in September 2020.

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 September 30, 2020, the currently known partnership obligations for the abandonment obligations are estimated at $68 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 $68 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, the new credit loss accounting standard adopted on January 1, 2020 requires recognition of a liability for expected credit losses related to the contingent obligations that are in the scope of these guarantees. With the adoption of this standard, Alliant Energy recorded a pre-tax $12 million cumulative effect adjustment to decrease the opening balance of retained earnings as of January 1, 2020.

Whiting Petroleum’s creditworthiness deteriorated in the first quarter of 2020, likely from significantly depressed oil and gas prices and general market conditions, and as a result, the credit loss liability was increased to $20 million in the first quarter of 2020. In April 2020, Whiting Petroleum filed for bankruptcy, and in September 2020, Whiting Petroleum completed its reorganization and emerged from bankruptcy. As a result of Whiting Petroleum’s completed bankruptcy proceedings, as well as additional information regarding the guarantees obtained from the bankruptcy proceedings, the credit loss liability was decreased to $5 million in the third quarter of 2020. The credit loss liability is recorded in “Other liabilities” on Alliant Energy’s balance sheet as of September 30, 2020. For the three and nine months ended September 30, 2020, the pre-tax credit loss adjustments of $15 million and $7 million, respectively, were recorded as reductions in Alliant Energy’s “Other operation and maintenance” expenses.

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 $74 million as of September 30, 2020 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 September 30, 2020 and December 31, 2019.

IPL’s Minnesota Electric Distribution Assets - IPL provided indemnifications associated with the 2015 sale of its Minnesota electric distribution assets for losses resulting from potential breach of IPL’s representations, warranties and obligations under the sale agreement. IPL has not recorded any material liabilities related to these indemnifications as of September 30, 2020 and December 31, 2019. The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expired in October 2020.

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 September 30, 2020, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At September 30, 2020, such amounts for WPL were not material.

	Alliant Energy				IPL
Range of estimated future costs		$12	-	$29		$9	-	$24
Current and non-current environmental liabilities	16				13

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 Burlington by December 31, 2021 and 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 to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: 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) Collective Bargaining Agreements - In August 2020, IPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 204 (Cedar Rapids) expired and a new agreement was reached, which expires August 31, 2024.

NOTE 13(f) MISO Transmission Owner Return on Equity Complaints - A group of MISO cooperative and municipal utilities previously filed complaints with FERC requesting a reduction to the base return on equity used by MISO transmission owners, including ITC Midwest LLC and ATC. The first complaint covered the period from November 12, 2013 through February 11, 2015. In 2017, IPL and WPL received refunds related to the first complaint period, which were subsequently refunded to their retail and wholesale customers. The second complaint covered the period from February 12, 2015 through May 11, 2016. In November 2019, FERC issued an order on the previously filed complaints and reduced the base return on equity used by the MISO transmission owners to 9.88% effective for the first complaint period and subsequent to September 28, 2016. The November 2019 FERC order also dismissed the second complaint; therefore, FERC did not direct refunds to be made for that complaint. In May 2020, FERC issued an order in response to various rehearing requests and increased the base return on equity used by the MISO transmission owners from 9.88% to 10.02% for the first complaint period and subsequent to September 28, 2016, which reduces the refunds originally anticipated to be received by IPL and WPL as a result of FERC’s November 2019 order.

For the nine months ended September 30, 2020, IPL and WPL received $15 million and $5 million, respectively, in refunds related to the FERC orders. In October 2020, FERC extended the time to complete additional refunds to September 2021.

IPL currently expects that all refunds will be returned to its retail electric customers after refund amounts and timing are known and a refund plan is approved by the IUB. WPL proposed to retain the refunds as part of WPL’s application with the PSCW to maintain its current retail electric base rates through the end of 2021. WPL currently expects that any refunds not utilized to maintain base rates would be returned to its customers in WPL’s next retail electric rate review proceeding. 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

9 Months Ended

Sep. 30, 2020

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 September 30, 2020
Revenues		$852		$42			$10		$904		$16		$920
Operating income (loss)	251		(1		)	1		251		21		272
Net income attributable to Alliant Energy common shareowners								221		25		246
Three Months Ended September 30, 2019
Revenues		$916		$42			$11		$969		$21		$990
Operating income (loss)	284		(5		)	3		282		8		290
Net income attributable to Alliant Energy common shareowners								217		9		226

Alliant Energy									ATC Holdings,		Alliant
	Utility								Non-Utility,		Energy
	Electric		Gas		Other		Total		Parent and Other		Consolidated
	(in millions)
Nine Months Ended September 30, 2020
Revenues		$2,257		$253		$32		$2,542		$57		$2,599
Operating income	549		48		5		602		26		628
Net income attributable to Alliant Energy common shareowners							510		40		550
Nine Months Ended September 30, 2019
Revenues		$2,350		$323		$33		$2,706		$62		$2,768
Operating income	543		47		5		595		22		617
Net income attributable to Alliant Energy common shareowners							422		24		446

IPL	Electric		Gas			Other		Total
	(in millions)
Three Months Ended September 30, 2020
Revenues		$519		$24			$10		$553
Operating income	159		1			2		162
Net income available for common stock								148
Three Months Ended September 30, 2019
Revenues		$561		$25			$11		$597
Operating income (loss)	175		(4		)	3		174
Net income available for common stock								141
Nine Months Ended September 30, 2020
Revenues		$1,332		$141			$31		$1,504
Operating income	308		34			5		347
Net income available for common stock								290
Nine Months Ended September 30, 2019
Revenues		$1,373		$188			$32		$1,593
Operating income	291		26			5		322
Net income available for common stock								239

WPL	Electric		Gas			Other			Total
	(in millions)
Three Months Ended September 30, 2020
Revenues		$333		$18			$—			$351
Operating income (loss)	92		(2		)	(1		)	89
Net income									73
Three Months Ended September 30, 2019
Revenues		$355		$17			$—			$372
Operating income (loss)	109		(1		)	—			108
Net income									76
Nine Months Ended September 30, 2020
Revenues		$925		$112			$1			$1,038
Operating income	241		14			—			255
Net income									220
Nine Months Ended September 30, 2019
Revenues		$977		$135			$1			$1,113
Operating income	252		21			—			273
Net income									183

IPL [Member]

Segment Reporting Information [Line Items]

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 September 30, 2020
Revenues		$852		$42			$10		$904		$16		$920
Operating income (loss)	251		(1		)	1		251		21		272
Net income attributable to Alliant Energy common shareowners								221		25		246
Three Months Ended September 30, 2019
Revenues		$916		$42			$11		$969		$21		$990
Operating income (loss)	284		(5		)	3		282		8		290
Net income attributable to Alliant Energy common shareowners								217		9		226

Alliant Energy									ATC Holdings,		Alliant
	Utility								Non-Utility,		Energy
	Electric		Gas		Other		Total		Parent and Other		Consolidated
	(in millions)
Nine Months Ended September 30, 2020
Revenues		$2,257		$253		$32		$2,542		$57		$2,599
Operating income	549		48		5		602		26		628
Net income attributable to Alliant Energy common shareowners							510		40		550
Nine Months Ended September 30, 2019
Revenues		$2,350		$323		$33		$2,706		$62		$2,768
Operating income	543		47		5		595		22		617
Net income attributable to Alliant Energy common shareowners							422		24		446

IPL	Electric		Gas			Other		Total
	(in millions)
Three Months Ended September 30, 2020
Revenues		$519		$24			$10		$553
Operating income	159		1			2		162
Net income available for common stock								148
Three Months Ended September 30, 2019
Revenues		$561		$25			$11		$597
Operating income (loss)	175		(4		)	3		174
Net income available for common stock								141
Nine Months Ended September 30, 2020
Revenues		$1,332		$141			$31		$1,504
Operating income	308		34			5		347
Net income available for common stock								290
Nine Months Ended September 30, 2019
Revenues		$1,373		$188			$32		$1,593
Operating income	291		26			5		322
Net income available for common stock								239

WPL	Electric		Gas			Other			Total
	(in millions)
Three Months Ended September 30, 2020
Revenues		$333		$18			$—			$351
Operating income (loss)	92		(2		)	(1		)	89
Net income									73
Three Months Ended September 30, 2019
Revenues		$355		$17			$—			$372
Operating income (loss)	109		(1		)	—			108
Net income									76
Nine Months Ended September 30, 2020
Revenues		$925		$112			$1			$1,038
Operating income	241		14			—			255
Net income									220
Nine Months Ended September 30, 2019
Revenues		$977		$135			$1			$1,113
Operating income	252		21			—			273
Net income									183

WPL [Member]

Segment Reporting Information [Line Items]

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 September 30, 2020
Revenues		$852		$42			$10		$904		$16		$920
Operating income (loss)	251		(1		)	1		251		21		272
Net income attributable to Alliant Energy common shareowners								221		25		246
Three Months Ended September 30, 2019
Revenues		$916		$42			$11		$969		$21		$990
Operating income (loss)	284		(5		)	3		282		8		290
Net income attributable to Alliant Energy common shareowners								217		9		226

Alliant Energy									ATC Holdings,		Alliant
	Utility								Non-Utility,		Energy
	Electric		Gas		Other		Total		Parent and Other		Consolidated
	(in millions)
Nine Months Ended September 30, 2020
Revenues		$2,257		$253		$32		$2,542		$57		$2,599
Operating income	549		48		5		602		26		628
Net income attributable to Alliant Energy common shareowners							510		40		550
Nine Months Ended September 30, 2019
Revenues		$2,350		$323		$33		$2,706		$62		$2,768
Operating income	543		47		5		595		22		617
Net income attributable to Alliant Energy common shareowners							422		24		446

IPL	Electric		Gas			Other		Total
	(in millions)
Three Months Ended September 30, 2020
Revenues		$519		$24			$10		$553
Operating income	159		1			2		162
Net income available for common stock								148
Three Months Ended September 30, 2019
Revenues		$561		$25			$11		$597
Operating income (loss)	175		(4		)	3		174
Net income available for common stock								141
Nine Months Ended September 30, 2020
Revenues		$1,332		$141			$31		$1,504
Operating income	308		34			5		347
Net income available for common stock								290
Nine Months Ended September 30, 2019
Revenues		$1,373		$188			$32		$1,593
Operating income	291		26			5		322
Net income available for common stock								239

WPL	Electric		Gas			Other			Total
	(in millions)
Three Months Ended September 30, 2020
Revenues		$333		$18			$—			$351
Operating income (loss)	92		(2		)	(1		)	89
Net income									73
Three Months Ended September 30, 2019
Revenues		$355		$17			$—			$372
Operating income (loss)	109		(1		)	—			108
Net income									76
Nine Months Ended September 30, 2020
Revenues		$925		$112			$1			$1,038
Operating income	241		14			—			255
Net income									220
Nine Months Ended September 30, 2019
Revenues		$977		$135			$1			$1,113
Operating income	252		21			—			273
Net income									183

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Related Parties

9 Months Ended

Sep. 30, 2020

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 nine months ended September 30 were as follows (in millions):

	IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months
	2020		2019		2020		2019		2020		2019		2020		2019
Corporate Services billings		$53		$47		$134		$137		$41		$36		$108		$104
Sales credited	10		23		35		50		—		2		4		6
Purchases billed	110		93		248		251		39		32		79		91

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

	IPL		WPL
	September 30, 2020	December 31, 2019	September 30, 2020	December 31, 2019
Net payables to Corporate Services	$119	$112	$77	$85

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 nine months ended September 30 were as follows (in millions):

	Three Months				Nine Months
	2020		2019		2020		2019
ATC billings to WPL		$27		$28		$80		$82
WPL billings to ATC	2		3		8		10

WPL owed ATC net amounts of $9 million as of September 30, 2020 and $9 million as of December 31, 2019. In the second quarter of 2020, WPL received $46 million from ATC related to construction deposits WPL previously provided ATC for transmission network upgrades for West Riverside, which is substantially recorded in “Other” in Alliant Energy’s and WPL’s cash flows from investing activities.

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 nine months ended September 30 were as follows (in millions):

	IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months
	2020		2019		2020		2019		2020		2019		2020		2019
Corporate Services billings		$53		$47		$134		$137		$41		$36		$108		$104
Sales credited	10		23		35		50		—		2		4		6
Purchases billed	110		93		248		251		39		32		79		91

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

	IPL		WPL
	September 30, 2020	December 31, 2019	September 30, 2020	December 31, 2019
Net payables to Corporate Services	$119	$112	$77	$85

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 nine months ended September 30 were as follows (in millions):

	IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months
	2020		2019		2020		2019		2020		2019		2020		2019
Corporate Services billings		$53		$47		$134		$137		$41		$36		$108		$104
Sales credited	10		23		35		50		—		2		4		6
Purchases billed	110		93		248		251		39		32		79		91

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

	IPL		WPL
	September 30, 2020	December 31, 2019	September 30, 2020	December 31, 2019
Net payables to Corporate Services	$119	$112	$77	$85

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 nine months ended September 30 were as follows (in millions):

	Three Months				Nine Months
	2020		2019		2020		2019
ATC billings to WPL		$27		$28		$80		$82
WPL billings to ATC	2		3		8		10

WPL owed ATC net amounts of $9 million as of September 30, 2020 and $9 million as of December 31, 2019. In the second quarter of 2020, WPL received $46 million from ATC related to construction deposits WPL previously provided ATC for transmission network upgrades for West Riverside, which is substantially recorded in “Other” in Alliant Energy’s and WPL’s cash flows from investing activities.

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Summary Of Significant Accounting Policies (Policy)

9 Months Ended

Sep. 30, 2020

General, Basis of Accounting

The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. 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 latest combined Annual Report on 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 nine months ended September 30, 2020 are not necessarily indicative of results that may be expected for the year ending December 31, 2020.

General, COVID-19

In March 2020, COVID-19 was declared a global pandemic, which has resulted in widespread travel restrictions, closures of commercial spaces and industrial facilities, and more people working from home in Alliant Energy’s service territories. For the three and nine months ended September 30, 2020, Alliant Energy, IPL and WPL considered the impact of COVID-19 on their overall business operations, financial condition, results of operations and cash flows, along with assumptions and estimates used. While the total expected impact of COVID-19 on future sales is currently unknown, Alliant Energy, IPL and WPL have experienced higher electric residential sales and lower electric commercial and industrial sales since the outset of the pandemic. The degree to which the COVID-19 pandemic may impact Alliant Energy, IPL and WPL in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities.

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.

Cash and Cash Equivalents

At September 30, 2020, Alliant Energy’s and IPL’s cash and cash equivalents included $183 million and $183 million of money market fund investments, with weighted average interest rates of 0.1% and 0.1%, respectively.

Current Expected Credit Losses Estimates

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

New Accounting Standards

Credit Losses - In June 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 13(c) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s summary of changes in shareowners’ equity in Note 5 for the nine months ended September 30, 2020.

IPL [Member]

General, Basis of Accounting

The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. 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 latest combined Annual Report on 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 nine months ended September 30, 2020 are not necessarily indicative of results that may be expected for the year ending December 31, 2020.

General, COVID-19

In March 2020, COVID-19 was declared a global pandemic, which has resulted in widespread travel restrictions, closures of commercial spaces and industrial facilities, and more people working from home in Alliant Energy’s service territories. For the three and nine months ended September 30, 2020, Alliant Energy, IPL and WPL considered the impact of COVID-19 on their overall business operations, financial condition, results of operations and cash flows, along with assumptions and estimates used. While the total expected impact of COVID-19 on future sales is currently unknown, Alliant Energy, IPL and WPL have experienced higher electric residential sales and lower electric commercial and industrial sales since the outset of the pandemic. The degree to which the COVID-19 pandemic may impact Alliant Energy, IPL and WPL in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities.

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.

Cash and Cash Equivalents

At September 30, 2020, Alliant Energy’s and IPL’s cash and cash equivalents included $183 million and $183 million of money market fund investments, with weighted average interest rates of 0.1% and 0.1%, respectively.

Current Expected Credit Losses Estimates

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

New Accounting Standards

Credit Losses - In June 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 13(c) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s summary of changes in shareowners’ equity in Note 5 for the nine months ended September 30, 2020.

WPL [Member]

General, Basis of Accounting

The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. 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 latest combined Annual Report on 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 nine months ended September 30, 2020 are not necessarily indicative of results that may be expected for the year ending December 31, 2020.

General, COVID-19

In March 2020, COVID-19 was declared a global pandemic, which has resulted in widespread travel restrictions, closures of commercial spaces and industrial facilities, and more people working from home in Alliant Energy’s service territories. For the three and nine months ended September 30, 2020, Alliant Energy, IPL and WPL considered the impact of COVID-19 on their overall business operations, financial condition, results of operations and cash flows, along with assumptions and estimates used. While the total expected impact of COVID-19 on future sales is currently unknown, Alliant Energy, IPL and WPL have experienced higher electric residential sales and lower electric commercial and industrial sales since the outset of the pandemic. The degree to which the COVID-19 pandemic may impact Alliant Energy, IPL and WPL in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities.

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.

Current Expected Credit Losses Estimates

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

New Accounting Standards

Credit Losses - In June 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 13(c) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s summary of changes in shareowners’ equity in Note 5 for the nine months ended September 30, 2020.

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Regulatory Matters (Tables)

9 Months Ended

Sep. 30, 2020

Regulatory Assets [Line Items]

Regulatory Assets

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

	Alliant Energy				IPL				WPL
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Tax-related		$877		$818		$829		$777		$48		$41
Pension and OPEB costs	492		524		247		263		245		261
Assets retired early	118		134		79		88		39		46
Asset retirement obligations	115		112		79		76		36		36
IPL’s DAEC PPA amendment	110		108		110		108		—		—
Derivatives	20		39		8		18		12		21
Emission allowances	19		21		19		21		—		—
Other	85		89		47		49		38		40
		$1,836		$1,845		$1,418		$1,400		$418		$445

Regulatory Liabilities

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

	Alliant Energy				IPL				WPL
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Tax-related		$746		$836		$334		$351		$412		$485
Cost of removal obligations	371		388		241		257		130		131
Electric transmission cost recovery	62		88		30		51		32		37
Derivatives	40		20		27		17		13		3
WPL’s West Riverside liquidated damages	36		—		—		—		36		—
Commodity cost recovery	22		24		19		9		3		15
WPL’s earnings sharing mechanism	22		22		—		—		22		22
Other	52		46		40		30		12		16
		$1,351		$1,424		$691		$715		$660		$709

IPL [Member]

Regulatory Assets [Line Items]

Regulatory Assets

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

	Alliant Energy				IPL				WPL
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Tax-related		$877		$818		$829		$777		$48		$41
Pension and OPEB costs	492		524		247		263		245		261
Assets retired early	118		134		79		88		39		46
Asset retirement obligations	115		112		79		76		36		36
IPL’s DAEC PPA amendment	110		108		110		108		—		—
Derivatives	20		39		8		18		12		21
Emission allowances	19		21		19		21		—		—
Other	85		89		47		49		38		40
		$1,836		$1,845		$1,418		$1,400		$418		$445

Regulatory Liabilities

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

	Alliant Energy				IPL				WPL
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Tax-related		$746		$836		$334		$351		$412		$485
Cost of removal obligations	371		388		241		257		130		131
Electric transmission cost recovery	62		88		30		51		32		37
Derivatives	40		20		27		17		13		3
WPL’s West Riverside liquidated damages	36		—		—		—		36		—
Commodity cost recovery	22		24		19		9		3		15
WPL’s earnings sharing mechanism	22		22		—		—		22		22
Other	52		46		40		30		12		16
		$1,351		$1,424		$691		$715		$660		$709

WPL [Member]

Regulatory Assets [Line Items]

Regulatory Assets

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

	Alliant Energy				IPL				WPL
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Tax-related		$877		$818		$829		$777		$48		$41
Pension and OPEB costs	492		524		247		263		245		261
Assets retired early	118		134		79		88		39		46
Asset retirement obligations	115		112		79		76		36		36
IPL’s DAEC PPA amendment	110		108		110		108		—		—
Derivatives	20		39		8		18		12		21
Emission allowances	19		21		19		21		—		—
Other	85		89		47		49		38		40
		$1,836		$1,845		$1,418		$1,400		$418		$445

Regulatory Liabilities

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

	Alliant Energy				IPL				WPL
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Tax-related		$746		$836		$334		$351		$412		$485
Cost of removal obligations	371		388		241		257		130		131
Electric transmission cost recovery	62		88		30		51		32		37
Derivatives	40		20		27		17		13		3
WPL’s West Riverside liquidated damages	36		—		—		—		36		—
Commodity cost recovery	22		24		19		9		3		15
WPL’s earnings sharing mechanism	22		22		—		—		22		22
Other	52		46		40		30		12		16
		$1,351		$1,424		$691		$715		$660		$709

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Receivables (Tables)

9 Months Ended

Sep. 30, 2020

Receivables [Line Items]

Accounts Receivable Details

Details for accounts receivable included on the balance sheets were as follows (in millions):

	Alliant Energy						IPL						WPL
	September 30, 2020			December 31, 2019			September 30, 2020			December 31, 2019			September 30, 2020			December 31, 2019
Customer		$95			$92			$—			$—			$86			$84
Unbilled utility revenues	62			82			—			—			62			82
Deferred proceeds	201			188			201			188			—			—
Other	54			47			20			16			33			31
Allowance for expected credit losses	(13		)	(7		)	(2		)	(1		)	(11		)	(6		)
		$399			$402			$219			$203			$170			$191

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 nine months ended September 30 were as follows (in millions):

	Three Months				Nine Months
	2020		2019		2020		2019
Maximum outstanding aggregate cash proceeds		$1		$103		$96		$108
Average outstanding aggregate cash proceeds	1		45		12		43

Schedule of Sales Of Accounts Receivable Sold Under Agreement Table Text Block

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

	September 30, 2020		December 31, 2019
Customer accounts receivable		$148		$125
Unbilled utility revenues	67		95
Other receivables	—		1
Receivables sold to third party	215		221
Less: cash proceeds	1		27
Deferred proceeds	214		194
Less: allowance for expected credit losses	13		6
Fair value of deferred proceeds		$201		$188

Additional Attributes Of Receivables Sold Under The Receivables Agreement

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

	Three Months				Nine Months
	2020		2019		2020		2019
Collections		$561		$592		$1,555		$1,636
Write-offs, net of recoveries	1		3		4		11

IPL [Member]

Receivables [Line Items]

Accounts Receivable Details

Details for accounts receivable included on the balance sheets were as follows (in millions):

	Alliant Energy						IPL						WPL
	September 30, 2020			December 31, 2019			September 30, 2020			December 31, 2019			September 30, 2020			December 31, 2019
Customer		$95			$92			$—			$—			$86			$84
Unbilled utility revenues	62			82			—			—			62			82
Deferred proceeds	201			188			201			188			—			—
Other	54			47			20			16			33			31
Allowance for expected credit losses	(13		)	(7		)	(2		)	(1		)	(11		)	(6		)
		$399			$402			$219			$203			$170			$191

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 nine months ended September 30 were as follows (in millions):

	Three Months				Nine Months
	2020		2019		2020		2019
Maximum outstanding aggregate cash proceeds		$1		$103		$96		$108
Average outstanding aggregate cash proceeds	1		45		12		43

Schedule of Sales Of Accounts Receivable Sold Under Agreement Table Text Block

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

	September 30, 2020		December 31, 2019
Customer accounts receivable		$148		$125
Unbilled utility revenues	67		95
Other receivables	—		1
Receivables sold to third party	215		221
Less: cash proceeds	1		27
Deferred proceeds	214		194
Less: allowance for expected credit losses	13		6
Fair value of deferred proceeds		$201		$188

Additional Attributes Of Receivables Sold Under The Receivables Agreement

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

	Three Months				Nine Months
	2020		2019		2020		2019
Collections		$561		$592		$1,555		$1,636
Write-offs, net of recoveries	1		3		4		11

WPL [Member]

Receivables [Line Items]

Accounts Receivable Details

Details for accounts receivable included on the balance sheets were as follows (in millions):

	Alliant Energy						IPL						WPL
	September 30, 2020			December 31, 2019			September 30, 2020			December 31, 2019			September 30, 2020			December 31, 2019
Customer		$95			$92			$—			$—			$86			$84
Unbilled utility revenues	62			82			—			—			62			82
Deferred proceeds	201			188			201			188			—			—
Other	54			47			20			16			33			31
Allowance for expected credit losses	(13		)	(7		)	(2		)	(1		)	(11		)	(6		)
		$399			$402			$219			$203			$170			$191

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Investments (Tables)

9 Months Ended

Sep. 30, 2020

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 nine months ended September 30 was as follows (in millions):

	Three Months						Nine Months
	2020			2019			2020			2019
ATC Holdings		($11	)		($11	)		($36	)		($30	)
Non-utility wind farm in Oklahoma	(2		)	—			(6		)	(3		)
Other	(2		)	(1		)	(4		)	(2		)
		($15	)		($12	)		($46	)		($35	)

XML

Common Equity (Tables)

9 Months Ended

Sep. 30, 2020

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, 2020	245,022,800
Equity forward agreements	4,275,127
Shareowner Direct Plan	364,531
Equity-based compensation plans	98,205
Shares outstanding, September 30, 2020	249,760,663

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			Cumulative
			Additional					Other			Deferred			Preferred
	Common		Paid-In		Retained			Comprehensive			Compensation			Stock		Total
	Stock		Capital		Earnings			Income (Loss)			Trust			of IPL		Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$2		$2,683		$2,874			($1	)		($10	)		$200		$5,748
Net income attributable to Alliant Energy common shareowners					246											246
Common stock dividends ($0.38 per share)					(94		)									(94		)
Shareowner Direct Plan issuances			6													6
Equity-based compensation plans and other			4								(1		)			3
Ending balance, September 30, 2020		$2		$2,693		$3,026			($1	)		($11	)		$200		$5,909
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$2		$2,109		$2,598			$1			($10	)		$200		$4,900
Net income attributable to Alliant Energy common shareowners					226											226
Common stock dividends ($0.355 per share)					(85		)									(85		)
Equity forward settlements and Shareowner Direct Plan issuances			125													125
Equity-based compensation plans and other			3													3
Ending balance, September 30, 2019		$2		$2,237		$2,739			$1			($10	)		$200		$5,169

Alliant Energy	Total Alliant Energy Common Equity
								Accumulated			Shares in			Cumulative
			Additional					Other			Deferred			Preferred
	Common		Paid-In		Retained			Comprehensive			Compensation			Stock		Total
	Stock		Capital		Earnings			Income (Loss)			Trust			of IPL		Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$2		$2,446		$2,766			$1			($10	)		$200		$5,405
Net income attributable to Alliant Energy common shareowners					550											550
Common stock dividends ($1.14 per share)					(281		)									(281		)
Equity forward settlements and Shareowner Direct Plan issuances			241													241
Equity-based compensation plans and other			6								(1		)			5
Adoption of new accounting standard, net of tax (refer to Note 1(d))					(9		)									(9		)
Other comprehensive loss, net of tax								(2		)						(2		)
Ending balance, September 30, 2020		$2		$2,693		$3,026			($1	)		($11	)		$200		$5,909
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$2		$2,046		$2,546			$2			($10	)		$200		$4,786
Net income attributable to Alliant Energy common shareowners					446											446
Common stock dividends ($1.065 per share)					(253		)									(253		)
Equity forward settlements and Shareowner Direct Plan issuances			185													185
Equity-based compensation plans and other			6													6
Other comprehensive loss, net of tax								(1		)						(1		)
Ending balance, September 30, 2019		$2		$2,237		$2,739			$1			($10	)		$200		$5,169

IPL	Total IPL Common Equity
			Additional					Cumulative
	Common		Paid-In		Retained			Preferred		Total
	Stock		Capital		Earnings			Stock		Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$33		$2,523		$915			$200		$3,671
Net income available for common stock					148					148
Common stock dividends					(59		)			(59		)
Capital contributions from parent			170							170
Ending balance, September 30, 2020		$33		$2,693		$1,004			$200		$3,930
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$33		$2,323		$789			$200		$3,345
Net income available for common stock					141					141
Common stock dividends					(42		)			(42		)
Ending balance, September 30, 2019		$33		$2,323		$888			$200		$3,444

IPL	Total IPL Common Equity
			Additional					Cumulative
	Common		Paid-In		Retained			Preferred		Total
	Stock		Capital		Earnings			Stock		Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$33		$2,348		$891			$200		$3,472
Net income available for common stock					290					290
Common stock dividends					(177		)			(177		)
Capital contributions from parent			345							345
Ending balance, September 30, 2020		$33		$2,693		$1,004			$200		$3,930
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$33		$2,223		$775			$200		$3,231
Net income available for common stock					239					239
Common stock dividends					(126		)			(126		)
Capital contributions from parent			100							100
Ending balance, September 30, 2019		$33		$2,323		$888			$200		$3,444

WPL			Additional					Total
	Common		Paid-In		Retained			Common
	Stock		Capital		Earnings			Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$66		$1,459		$927			$2,452
Net income					73			73
Common stock dividends					(43		)	(43		)
Ending balance, September 30, 2020		$66		$1,459		$957			$2,482
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$66		$1,309		$810			$2,185
Net income					76			76
Common stock dividends					(36		)	(36		)
Capital contributions from parent			100					100
Ending balance, September 30, 2019		$66		$1,409		$850			$2,325

WPL			Additional					Total
	Common		Paid-In		Retained			Common
	Stock		Capital		Earnings			Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$66		$1,434		$864			$2,364
Net income					220			220
Common stock dividends					(127		)	(127		)
Capital contributions from parent			25					25
Ending balance, September 30, 2020		$66		$1,459		$957			$2,482
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$66		$1,309		$775			$2,150
Net income					183			183
Common stock dividends					(108		)	(108		)
Capital contributions from parent			100					100
Ending balance, September 30, 2019		$66		$1,409		$850			$2,325

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			Cumulative
			Additional					Other			Deferred			Preferred
	Common		Paid-In		Retained			Comprehensive			Compensation			Stock		Total
	Stock		Capital		Earnings			Income (Loss)			Trust			of IPL		Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$2		$2,683		$2,874			($1	)		($10	)		$200		$5,748
Net income attributable to Alliant Energy common shareowners					246											246
Common stock dividends ($0.38 per share)					(94		)									(94		)
Shareowner Direct Plan issuances			6													6
Equity-based compensation plans and other			4								(1		)			3
Ending balance, September 30, 2020		$2		$2,693		$3,026			($1	)		($11	)		$200		$5,909
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$2		$2,109		$2,598			$1			($10	)		$200		$4,900
Net income attributable to Alliant Energy common shareowners					226											226
Common stock dividends ($0.355 per share)					(85		)									(85		)
Equity forward settlements and Shareowner Direct Plan issuances			125													125
Equity-based compensation plans and other			3													3
Ending balance, September 30, 2019		$2		$2,237		$2,739			$1			($10	)		$200		$5,169

Alliant Energy	Total Alliant Energy Common Equity
								Accumulated			Shares in			Cumulative
			Additional					Other			Deferred			Preferred
	Common		Paid-In		Retained			Comprehensive			Compensation			Stock		Total
	Stock		Capital		Earnings			Income (Loss)			Trust			of IPL		Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$2		$2,446		$2,766			$1			($10	)		$200		$5,405
Net income attributable to Alliant Energy common shareowners					550											550
Common stock dividends ($1.14 per share)					(281		)									(281		)
Equity forward settlements and Shareowner Direct Plan issuances			241													241
Equity-based compensation plans and other			6								(1		)			5
Adoption of new accounting standard, net of tax (refer to Note 1(d))					(9		)									(9		)
Other comprehensive loss, net of tax								(2		)						(2		)
Ending balance, September 30, 2020		$2		$2,693		$3,026			($1	)		($11	)		$200		$5,909
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$2		$2,046		$2,546			$2			($10	)		$200		$4,786
Net income attributable to Alliant Energy common shareowners					446											446
Common stock dividends ($1.065 per share)					(253		)									(253		)
Equity forward settlements and Shareowner Direct Plan issuances			185													185
Equity-based compensation plans and other			6													6
Other comprehensive loss, net of tax								(1		)						(1		)
Ending balance, September 30, 2019		$2		$2,237		$2,739			$1			($10	)		$200		$5,169

IPL	Total IPL Common Equity
			Additional					Cumulative
	Common		Paid-In		Retained			Preferred		Total
	Stock		Capital		Earnings			Stock		Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$33		$2,523		$915			$200		$3,671
Net income available for common stock					148					148
Common stock dividends					(59		)			(59		)
Capital contributions from parent			170							170
Ending balance, September 30, 2020		$33		$2,693		$1,004			$200		$3,930
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$33		$2,323		$789			$200		$3,345
Net income available for common stock					141					141
Common stock dividends					(42		)			(42		)
Ending balance, September 30, 2019		$33		$2,323		$888			$200		$3,444

IPL	Total IPL Common Equity
			Additional					Cumulative
	Common		Paid-In		Retained			Preferred		Total
	Stock		Capital		Earnings			Stock		Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$33		$2,348		$891			$200		$3,472
Net income available for common stock					290					290
Common stock dividends					(177		)			(177		)
Capital contributions from parent			345							345
Ending balance, September 30, 2020		$33		$2,693		$1,004			$200		$3,930
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$33		$2,223		$775			$200		$3,231
Net income available for common stock					239					239
Common stock dividends					(126		)			(126		)
Capital contributions from parent			100							100
Ending balance, September 30, 2019		$33		$2,323		$888			$200		$3,444

WPL			Additional					Total
	Common		Paid-In		Retained			Common
	Stock		Capital		Earnings			Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$66		$1,459		$927			$2,452
Net income					73			73
Common stock dividends					(43		)	(43		)
Ending balance, September 30, 2020		$66		$1,459		$957			$2,482
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$66		$1,309		$810			$2,185
Net income					76			76
Common stock dividends					(36		)	(36		)
Capital contributions from parent			100					100
Ending balance, September 30, 2019		$66		$1,409		$850			$2,325

WPL			Additional					Total
	Common		Paid-In		Retained			Common
	Stock		Capital		Earnings			Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$66		$1,434		$864			$2,364
Net income					220			220
Common stock dividends					(127		)	(127		)
Capital contributions from parent			25					25
Ending balance, September 30, 2020		$66		$1,459		$957			$2,482
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$66		$1,309		$775			$2,150
Net income					183			183
Common stock dividends					(108		)	(108		)
Capital contributions from parent			100					100
Ending balance, September 30, 2019		$66		$1,409		$850			$2,325

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			Cumulative
			Additional					Other			Deferred			Preferred
	Common		Paid-In		Retained			Comprehensive			Compensation			Stock		Total
	Stock		Capital		Earnings			Income (Loss)			Trust			of IPL		Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$2		$2,683		$2,874			($1	)		($10	)		$200		$5,748
Net income attributable to Alliant Energy common shareowners					246											246
Common stock dividends ($0.38 per share)					(94		)									(94		)
Shareowner Direct Plan issuances			6													6
Equity-based compensation plans and other			4								(1		)			3
Ending balance, September 30, 2020		$2		$2,693		$3,026			($1	)		($11	)		$200		$5,909
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$2		$2,109		$2,598			$1			($10	)		$200		$4,900
Net income attributable to Alliant Energy common shareowners					226											226
Common stock dividends ($0.355 per share)					(85		)									(85		)
Equity forward settlements and Shareowner Direct Plan issuances			125													125
Equity-based compensation plans and other			3													3
Ending balance, September 30, 2019		$2		$2,237		$2,739			$1			($10	)		$200		$5,169

Alliant Energy	Total Alliant Energy Common Equity
								Accumulated			Shares in			Cumulative
			Additional					Other			Deferred			Preferred
	Common		Paid-In		Retained			Comprehensive			Compensation			Stock		Total
	Stock		Capital		Earnings			Income (Loss)			Trust			of IPL		Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$2		$2,446		$2,766			$1			($10	)		$200		$5,405
Net income attributable to Alliant Energy common shareowners					550											550
Common stock dividends ($1.14 per share)					(281		)									(281		)
Equity forward settlements and Shareowner Direct Plan issuances			241													241
Equity-based compensation plans and other			6								(1		)			5
Adoption of new accounting standard, net of tax (refer to Note 1(d))					(9		)									(9		)
Other comprehensive loss, net of tax								(2		)						(2		)
Ending balance, September 30, 2020		$2		$2,693		$3,026			($1	)		($11	)		$200		$5,909
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$2		$2,046		$2,546			$2			($10	)		$200		$4,786
Net income attributable to Alliant Energy common shareowners					446											446
Common stock dividends ($1.065 per share)					(253		)									(253		)
Equity forward settlements and Shareowner Direct Plan issuances			185													185
Equity-based compensation plans and other			6													6
Other comprehensive loss, net of tax								(1		)						(1		)
Ending balance, September 30, 2019		$2		$2,237		$2,739			$1			($10	)		$200		$5,169

IPL	Total IPL Common Equity
			Additional					Cumulative
	Common		Paid-In		Retained			Preferred		Total
	Stock		Capital		Earnings			Stock		Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$33		$2,523		$915			$200		$3,671
Net income available for common stock					148					148
Common stock dividends					(59		)			(59		)
Capital contributions from parent			170							170
Ending balance, September 30, 2020		$33		$2,693		$1,004			$200		$3,930
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$33		$2,323		$789			$200		$3,345
Net income available for common stock					141					141
Common stock dividends					(42		)			(42		)
Ending balance, September 30, 2019		$33		$2,323		$888			$200		$3,444

IPL	Total IPL Common Equity
			Additional					Cumulative
	Common		Paid-In		Retained			Preferred		Total
	Stock		Capital		Earnings			Stock		Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$33		$2,348		$891			$200		$3,472
Net income available for common stock					290					290
Common stock dividends					(177		)			(177		)
Capital contributions from parent			345							345
Ending balance, September 30, 2020		$33		$2,693		$1,004			$200		$3,930
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$33		$2,223		$775			$200		$3,231
Net income available for common stock					239					239
Common stock dividends					(126		)			(126		)
Capital contributions from parent			100							100
Ending balance, September 30, 2019		$33		$2,323		$888			$200		$3,444

WPL			Additional					Total
	Common		Paid-In		Retained			Common
	Stock		Capital		Earnings			Equity
Three Months Ended September 30, 2020
Beginning balance, June 30, 2020		$66		$1,459		$927			$2,452
Net income					73			73
Common stock dividends					(43		)	(43		)
Ending balance, September 30, 2020		$66		$1,459		$957			$2,482
Three Months Ended September 30, 2019
Beginning balance, June 30, 2019		$66		$1,309		$810			$2,185
Net income					76			76
Common stock dividends					(36		)	(36		)
Capital contributions from parent			100					100
Ending balance, September 30, 2019		$66		$1,409		$850			$2,325

WPL			Additional					Total
	Common		Paid-In		Retained			Common
	Stock		Capital		Earnings			Equity
Nine Months Ended September 30, 2020
Beginning balance, December 31, 2019		$66		$1,434		$864			$2,364
Net income					220			220
Common stock dividends					(127		)	(127		)
Capital contributions from parent			25					25
Ending balance, September 30, 2020		$66		$1,459		$957			$2,482
Nine Months Ended September 30, 2019
Beginning balance, December 31, 2018		$66		$1,309		$775			$2,150
Net income					183			183
Common stock dividends					(108		)	(108		)
Capital contributions from parent			100					100
Ending balance, September 30, 2019		$66		$1,409		$850			$2,325

XML

Debt (Tables)

9 Months Ended

Sep. 30, 2020

Short-term Debt [Line Items]

Other Short-Term Borrowings

Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, which currently expires in August 2023, classified as short-term debt was as follows (dollars in millions):

September 30, 2020	Alliant Energy	IPL	WPL
Amount outstanding	$422	$—	$139
Weighted average interest rates	0.2%	N/A	0.1%
Available credit facility capacity	$578	$250	$161

	Alliant Energy				IPL				WPL
Three Months Ended September 30	2020		2019		2020		2019		2020		2019
Maximum amount outstanding (based on daily outstanding balances)		$422		$472		$—		$—		$139		$90
Average amount outstanding (based on daily outstanding balances)		$252		$400		$—		$—		$83		$27
Weighted average interest rates	0.2%		2.5%		N/A		N/A		0.2%		2.3%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)		$463		$601		$8		$50		$212		$195
Average amount outstanding (based on daily outstanding balances)		$252		$476		$—		$—		$86		$102
Weighted average interest rates	1.1%		2.6%		0.5%		2.8%		1.2%		2.5%

IPL [Member]

Short-term Debt [Line Items]

Other Short-Term Borrowings

Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, which currently expires in August 2023, classified as short-term debt was as follows (dollars in millions):

September 30, 2020	Alliant Energy	IPL	WPL
Amount outstanding	$422	$—	$139
Weighted average interest rates	0.2%	N/A	0.1%
Available credit facility capacity	$578	$250	$161

	Alliant Energy				IPL				WPL
Three Months Ended September 30	2020		2019		2020		2019		2020		2019
Maximum amount outstanding (based on daily outstanding balances)		$422		$472		$—		$—		$139		$90
Average amount outstanding (based on daily outstanding balances)		$252		$400		$—		$—		$83		$27
Weighted average interest rates	0.2%		2.5%		N/A		N/A		0.2%		2.3%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)		$463		$601		$8		$50		$212		$195
Average amount outstanding (based on daily outstanding balances)		$252		$476		$—		$—		$86		$102
Weighted average interest rates	1.1%		2.6%		0.5%		2.8%		1.2%		2.5%

WPL [Member]

Short-term Debt [Line Items]

Other Short-Term Borrowings

Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, which currently expires in August 2023, classified as short-term debt was as follows (dollars in millions):

September 30, 2020	Alliant Energy	IPL	WPL
Amount outstanding	$422	$—	$139
Weighted average interest rates	0.2%	N/A	0.1%
Available credit facility capacity	$578	$250	$161

	Alliant Energy				IPL				WPL
Three Months Ended September 30	2020		2019		2020		2019		2020		2019
Maximum amount outstanding (based on daily outstanding balances)		$422		$472		$—		$—		$139		$90
Average amount outstanding (based on daily outstanding balances)		$252		$400		$—		$—		$83		$27
Weighted average interest rates	0.2%		2.5%		N/A		N/A		0.2%		2.3%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)		$463		$601		$8		$50		$212		$195
Average amount outstanding (based on daily outstanding balances)		$252		$476		$—		$—		$86		$102
Weighted average interest rates	1.1%		2.6%		0.5%		2.8%		1.2%		2.5%

XML

Revenues (Tables)

9 Months Ended

Sep. 30, 2020

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 September 30	2020		2019		2020		2019		2020		2019
Electric Utility:
Retail - residential		$328		$332		$189		$196		$139		$136
Retail - commercial	210		231		142		158		68		73
Retail - industrial	241		264		149		158		92		106
Wholesale	47		50		17		18		30		32
Bulk power and other	26		39		22		31		4		8
Total Electric Utility	852		916		519		561		333		355
Gas Utility:
Retail - residential	22		20		12		12		10		8
Retail - commercial	10		10		6		6		4		4
Retail - industrial	2		3		1		2		1		1
Transportation/other	8		9		5		5		3		4
Total Gas Utility	42		42		24		25		18		17
Other Utility:
Steam	8		9		8		9		—		—
Other utility	2		2		2		2		—		—
Total Other Utility	10		11		10		11		—		—
Non-Utility and Other:
Transportation and other	16		21		—		—		—		—
Total Non-Utility and Other	16		21		—		—		—		—
Total revenues		$920		$990		$553		$597		$351		$372

	Alliant Energy				IPL				WPL
Nine Months Ended September 30	2020		2019		2020		2019		2020		2019
Electric Utility:
Retail - residential		$845		$840		$472		$470		$373		$370
Retail - commercial	556		583		371		386		185		197
Retail - industrial	648		686		384		392		264		294
Wholesale	127		137		44		49		83		88
Bulk power and other	81		104		61		76		20		28
Total Electric Utility	2,257		2,350		1,332		1,373		925		977
Gas Utility:
Retail - residential	146		187		79		109		67		78
Retail - commercial	70		90		38		50		32		40
Retail - industrial	8		10		5		7		3		3
Transportation/other	29		36		19		22		10		14
Total Gas Utility	253		323		141		188		112		135
Other Utility:
Steam	27		27		27		27		—		—
Other utility	5		6		4		5		1		1
Total Other Utility	32		33		31		32		1		1
Non-Utility and Other:
Transportation and other	57		62		—		—		—		—
Total Non-Utility and Other	57		62		—		—		—		—
Total revenues		$2,599		$2,768		$1,504		$1,593		$1,038		$1,113

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 September 30	2020		2019		2020		2019		2020		2019
Electric Utility:
Retail - residential		$328		$332		$189		$196		$139		$136
Retail - commercial	210		231		142		158		68		73
Retail - industrial	241		264		149		158		92		106
Wholesale	47		50		17		18		30		32
Bulk power and other	26		39		22		31		4		8
Total Electric Utility	852		916		519		561		333		355
Gas Utility:
Retail - residential	22		20		12		12		10		8
Retail - commercial	10		10		6		6		4		4
Retail - industrial	2		3		1		2		1		1
Transportation/other	8		9		5		5		3		4
Total Gas Utility	42		42		24		25		18		17
Other Utility:
Steam	8		9		8		9		—		—
Other utility	2		2		2		2		—		—
Total Other Utility	10		11		10		11		—		—
Non-Utility and Other:
Transportation and other	16		21		—		—		—		—
Total Non-Utility and Other	16		21		—		—		—		—
Total revenues		$920		$990		$553		$597		$351		$372

	Alliant Energy				IPL				WPL
Nine Months Ended September 30	2020		2019		2020		2019		2020		2019
Electric Utility:
Retail - residential		$845		$840		$472		$470		$373		$370
Retail - commercial	556		583		371		386		185		197
Retail - industrial	648		686		384		392		264		294
Wholesale	127		137		44		49		83		88
Bulk power and other	81		104		61		76		20		28
Total Electric Utility	2,257		2,350		1,332		1,373		925		977
Gas Utility:
Retail - residential	146		187		79		109		67		78
Retail - commercial	70		90		38		50		32		40
Retail - industrial	8		10		5		7		3		3
Transportation/other	29		36		19		22		10		14
Total Gas Utility	253		323		141		188		112		135
Other Utility:
Steam	27		27		27		27		—		—
Other utility	5		6		4		5		1		1
Total Other Utility	32		33		31		32		1		1
Non-Utility and Other:
Transportation and other	57		62		—		—		—		—
Total Non-Utility and Other	57		62		—		—		—		—
Total revenues		$2,599		$2,768		$1,504		$1,593		$1,038		$1,113

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 September 30	2020		2019		2020		2019		2020		2019
Electric Utility:
Retail - residential		$328		$332		$189		$196		$139		$136
Retail - commercial	210		231		142		158		68		73
Retail - industrial	241		264		149		158		92		106
Wholesale	47		50		17		18		30		32
Bulk power and other	26		39		22		31		4		8
Total Electric Utility	852		916		519		561		333		355
Gas Utility:
Retail - residential	22		20		12		12		10		8
Retail - commercial	10		10		6		6		4		4
Retail - industrial	2		3		1		2		1		1
Transportation/other	8		9		5		5		3		4
Total Gas Utility	42		42		24		25		18		17
Other Utility:
Steam	8		9		8		9		—		—
Other utility	2		2		2		2		—		—
Total Other Utility	10		11		10		11		—		—
Non-Utility and Other:
Transportation and other	16		21		—		—		—		—
Total Non-Utility and Other	16		21		—		—		—		—
Total revenues		$920		$990		$553		$597		$351		$372

	Alliant Energy				IPL				WPL
Nine Months Ended September 30	2020		2019		2020		2019		2020		2019
Electric Utility:
Retail - residential		$845		$840		$472		$470		$373		$370
Retail - commercial	556		583		371		386		185		197
Retail - industrial	648		686		384		392		264		294
Wholesale	127		137		44		49		83		88
Bulk power and other	81		104		61		76		20		28
Total Electric Utility	2,257		2,350		1,332		1,373		925		977
Gas Utility:
Retail - residential	146		187		79		109		67		78
Retail - commercial	70		90		38		50		32		40
Retail - industrial	8		10		5		7		3		3
Transportation/other	29		36		19		22		10		14
Total Gas Utility	253		323		141		188		112		135
Other Utility:
Steam	27		27		27		27		—		—
Other utility	5		6		4		5		1		1
Total Other Utility	32		33		31		32		1		1
Non-Utility and Other:
Transportation and other	57		62		—		—		—		—
Total Non-Utility and Other	57		62		—		—		—		—
Total revenues		$2,599		$2,768		$1,504		$1,593		$1,038		$1,113

XML

Income Taxes (Tables)

9 Months Ended

Sep. 30, 2020

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. The decreases in overall effective income tax rates for the three and nine months ended September 30, 2020 compared to the same periods in 2019 were primarily due to increases in production tax credits as a result of increased wind production in 2020 and increased amortization of excess deferred taxes primarily at WPL, which were used to offset increases in WPL’s 2020 increased revenue requirements.

	Alliant Energy				IPL				WPL
	Three Months		Nine Months		Three Months		Nine Months		Three Months		Nine Months
	2020	2019	2020	2019	2020	2019	2020	2019	2020	2019	2020	2019
Overall income tax rate	(9%)	9%	(9%)	10%	(14%)	5%	(14%)	4%	(7%)	18%	(8%)	18%

Summary Of Tax Credit Carryforwards

At September 30, 2020, carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy		IPL		WPL
Federal net operating losses	2037		$371		$343		$3
State net operating losses	2020-2040	623		10		2
Federal tax credits	2022-2040	446		252		173

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. The decreases in overall effective income tax rates for the three and nine months ended September 30, 2020 compared to the same periods in 2019 were primarily due to increases in production tax credits as a result of increased wind production in 2020 and increased amortization of excess deferred taxes primarily at WPL, which were used to offset increases in WPL’s 2020 increased revenue requirements.

	Alliant Energy				IPL				WPL
	Three Months		Nine Months		Three Months		Nine Months		Three Months		Nine Months
	2020	2019	2020	2019	2020	2019	2020	2019	2020	2019	2020	2019
Overall income tax rate	(9%)	9%	(9%)	10%	(14%)	5%	(14%)	4%	(7%)	18%	(8%)	18%

Summary Of Tax Credit Carryforwards

At September 30, 2020, carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy		IPL		WPL
Federal net operating losses	2037		$371		$343		$3
State net operating losses	2020-2040	623		10		2
Federal tax credits	2022-2040	446		252		173

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. The decreases in overall effective income tax rates for the three and nine months ended September 30, 2020 compared to the same periods in 2019 were primarily due to increases in production tax credits as a result of increased wind production in 2020 and increased amortization of excess deferred taxes primarily at WPL, which were used to offset increases in WPL’s 2020 increased revenue requirements.

	Alliant Energy				IPL				WPL
	Three Months		Nine Months		Three Months		Nine Months		Three Months		Nine Months
	2020	2019	2020	2019	2020	2019	2020	2019	2020	2019	2020	2019
Overall income tax rate	(9%)	9%	(9%)	10%	(14%)	5%	(14%)	4%	(7%)	18%	(8%)	18%

Summary Of Tax Credit Carryforwards

At September 30, 2020, carryforwards and expiration dates were estimated as follows (in millions):

	Range of Expiration Dates	Alliant Energy		IPL		WPL
Federal net operating losses	2037		$371		$343		$3
State net operating losses	2020-2040	623		10		2
Federal tax credits	2022-2040	446		252		173

XML

Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2020

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 nine months ended September 30 are included below (in millions). For IPL and WPL, amounts represent those 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						Nine Months						Three Months						Nine Months
Alliant Energy	2020			2019			2020			2019			2020			2019			2020			2019
Service cost		$3			$2			$8			$7			$1			$1			$3			$3
Interest cost	10			13			32			37			2			2			5			6
Expected return on plan assets	(17		)	(15		)	(52		)	(45		)	(1		)	(1		)	(4		)	(4		)
Amortization of actuarial loss	9			9			26			27			—			1			2			2
Settlement losses (a)	—			—			4			—			—			—			—			—
		$5			$9			$18			$26			$2			$3			$6			$7

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
IPL	2020			2019			2020			2019			2020			2019			2020			2019
Service cost		$2			$1			$5			$4			$—			$—			$1			$1
Interest cost	5			6			15			17			1			1			2			3
Expected return on plan assets	(8		)	(7		)	(24		)	(21		)	(1		)	(1		)	(3		)	(3		)
Amortization of actuarial loss	4			4			11			12			—			1			1			1
		$3			$4			$7			$12			$—			$1			$1			$2

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months					Nine Months
WPL	2020			2019			2020			2019			2020			2019		2020			2019
Service cost		$1			$1			$3			$3			$—			$—		$1			$1
Interest cost	5			5			14			16			1			1		2			3
Expected return on plan assets	(8		)	(6		)	(23		)	(20		)	(1		)	—		(1		)	(1		)
Amortization of actuarial loss	4			4			12			13			1			—		2			1
		$2			$4			$6			$12			$1			$1		$4			$4

(a) Settlement losses related to payments made to retired executives of Alliant Energy.

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 nine months ended September 30 was as follows (in millions):

	Alliant Energy								IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months				Three Months				Nine Months
	2020		2019		2020		2019		2020		2019		2020		2019		2020		2019		2020		2019
Compensation expense		$5		$8		$10		$16		$3		$4		$6		$9		$2		$3		$4		$6
Income tax benefits	1		2		3		4		1		1		2		2		—		1		1		2

Schedule Of Equity-based Compensation Plans Activity

For the nine months ended September 30, 2020, performance shares, performance restricted stock units and restricted stock units were granted to key employees as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards. As of September 30, 2020, 276,070 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

		Weighted Average
	Grants	Grant Date Fair Value
Performance shares	55,303		$64.04
Performance restricted stock units	55,303	59.47
Restricted stock units	60,284	59.49

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 nine months ended September 30 are included below (in millions). For IPL and WPL, amounts represent those 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						Nine Months						Three Months						Nine Months
Alliant Energy	2020			2019			2020			2019			2020			2019			2020			2019
Service cost		$3			$2			$8			$7			$1			$1			$3			$3
Interest cost	10			13			32			37			2			2			5			6
Expected return on plan assets	(17		)	(15		)	(52		)	(45		)	(1		)	(1		)	(4		)	(4		)
Amortization of actuarial loss	9			9			26			27			—			1			2			2
Settlement losses (a)	—			—			4			—			—			—			—			—
		$5			$9			$18			$26			$2			$3			$6			$7

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
IPL	2020			2019			2020			2019			2020			2019			2020			2019
Service cost		$2			$1			$5			$4			$—			$—			$1			$1
Interest cost	5			6			15			17			1			1			2			3
Expected return on plan assets	(8		)	(7		)	(24		)	(21		)	(1		)	(1		)	(3		)	(3		)
Amortization of actuarial loss	4			4			11			12			—			1			1			1
		$3			$4			$7			$12			$—			$1			$1			$2

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months					Nine Months
WPL	2020			2019			2020			2019			2020			2019		2020			2019
Service cost		$1			$1			$3			$3			$—			$—		$1			$1
Interest cost	5			5			14			16			1			1		2			3
Expected return on plan assets	(8		)	(6		)	(23		)	(20		)	(1		)	—		(1		)	(1		)
Amortization of actuarial loss	4			4			12			13			1			—		2			1
		$2			$4			$6			$12			$1			$1		$4			$4

(a) Settlement losses related to payments made to retired executives of Alliant Energy.

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 nine months ended September 30 was as follows (in millions):

	Alliant Energy								IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months				Three Months				Nine Months
	2020		2019		2020		2019		2020		2019		2020		2019		2020		2019		2020		2019
Compensation expense		$5		$8		$10		$16		$3		$4		$6		$9		$2		$3		$4		$6
Income tax benefits	1		2		3		4		1		1		2		2		—		1		1		2

Schedule Of Equity-based Compensation Plans Activity

For the nine months ended September 30, 2020, performance shares, performance restricted stock units and restricted stock units were granted to key employees as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards. As of September 30, 2020, 276,070 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

		Weighted Average
	Grants	Grant Date Fair Value
Performance shares	55,303		$64.04
Performance restricted stock units	55,303	59.47
Restricted stock units	60,284	59.49

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 nine months ended September 30 are included below (in millions). For IPL and WPL, amounts represent those 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						Nine Months						Three Months						Nine Months
Alliant Energy	2020			2019			2020			2019			2020			2019			2020			2019
Service cost		$3			$2			$8			$7			$1			$1			$3			$3
Interest cost	10			13			32			37			2			2			5			6
Expected return on plan assets	(17		)	(15		)	(52		)	(45		)	(1		)	(1		)	(4		)	(4		)
Amortization of actuarial loss	9			9			26			27			—			1			2			2
Settlement losses (a)	—			—			4			—			—			—			—			—
		$5			$9			$18			$26			$2			$3			$6			$7

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
IPL	2020			2019			2020			2019			2020			2019			2020			2019
Service cost		$2			$1			$5			$4			$—			$—			$1			$1
Interest cost	5			6			15			17			1			1			2			3
Expected return on plan assets	(8		)	(7		)	(24		)	(21		)	(1		)	(1		)	(3		)	(3		)
Amortization of actuarial loss	4			4			11			12			—			1			1			1
		$3			$4			$7			$12			$—			$1			$1			$2

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months					Nine Months
WPL	2020			2019			2020			2019			2020			2019		2020			2019
Service cost		$1			$1			$3			$3			$—			$—		$1			$1
Interest cost	5			5			14			16			1			1		2			3
Expected return on plan assets	(8		)	(6		)	(23		)	(20		)	(1		)	—		(1		)	(1		)
Amortization of actuarial loss	4			4			12			13			1			—		2			1
		$2			$4			$6			$12			$1			$1		$4			$4

(a) Settlement losses related to payments made to retired executives of Alliant Energy.

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 nine months ended September 30 was as follows (in millions):

	Alliant Energy								IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months				Three Months				Nine Months
	2020		2019		2020		2019		2020		2019		2020		2019		2020		2019		2020		2019
Compensation expense		$5		$8		$10		$16		$3		$4		$6		$9		$2		$3		$4		$6
Income tax benefits	1		2		3		4		1		1		2		2		—		1		1		2

Schedule Of Equity-based Compensation Plans Activity

For the nine months ended September 30, 2020, performance shares, performance restricted stock units and restricted stock units were granted to key employees as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards. As of September 30, 2020, 276,070 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

		Weighted Average
	Grants	Grant Date Fair Value
Performance shares	55,303		$64.04
Performance restricted stock units	55,303	59.47
Restricted stock units	60,284	59.49

XML

Asset Retirement Obligations (Tables)

9 Months Ended

Sep. 30, 2020

Schedule of Asset Retirement Obligations [Line Items]

Reconciliation of Changes in Asset Retirement Obligations

A reconciliation of the changes in asset retirement obligations associated with long-lived assets for the nine months ended September 30, 2020 is as follows (in millions):

	Alliant Energy			IPL
Balance, January 1		$196			$134
Revisions in estimated cash flows	1			—
Liabilities settled	(7		)	(5		)
Liabilities incurred (a)	38			38
Accretion expense	5			4
Balance, September 30		$233			$171

(a)

During the nine months ended September 30, 2020, Alliant Energy and IPL recognized additional asset retirement obligations related to IPL’s newly constructed Whispering Willow North, Golden Plains and Richland wind sites. The increases in asset retirement obligations resulted in corresponding increases in property, plant and equipment, net on the respective balance sheets.

IPL [Member]

Schedule of Asset Retirement Obligations [Line Items]

Reconciliation of Changes in Asset Retirement Obligations

A reconciliation of the changes in asset retirement obligations associated with long-lived assets for the nine months ended September 30, 2020 is as follows (in millions):

	Alliant Energy			IPL
Balance, January 1		$196			$134
Revisions in estimated cash flows	1			—
Liabilities settled	(7		)	(5		)
Liabilities incurred (a)	38			38
Accretion expense	5			4
Balance, September 30		$233			$171

(a)

During the nine months ended September 30, 2020, Alliant Energy and IPL recognized additional asset retirement obligations related to IPL’s newly constructed Whispering Willow North, Golden Plains and Richland wind sites. The increases in asset retirement obligations resulted in corresponding increases in property, plant and equipment, net on the respective balance sheets.

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Derivative Instruments (Tables)

9 Months Ended

Sep. 30, 2020

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

As of September 30, 2020, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):

	FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	14,365	2020-2021	218,581	2020-2028	8,151	2020-2023	6,174	2020-2022
IPL	5,401	2020-2021	114,747	2020-2028	3,373	2020-2023	—	—
WPL	8,964	2020-2021	103,834	2020-2027	4,778	2020-2023	6,174	2020-2022

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
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Current derivative assets		$33		$16		$23		$12		$10		$4
Non-current derivative assets	15		11		11		10		4		1
Current derivative liabilities	6		19		2		9		4		10
Non-current derivative liabilities	13		19		6		9		7		10

IPL [Member]

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

As of September 30, 2020, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):

	FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	14,365	2020-2021	218,581	2020-2028	8,151	2020-2023	6,174	2020-2022
IPL	5,401	2020-2021	114,747	2020-2028	3,373	2020-2023	—	—
WPL	8,964	2020-2021	103,834	2020-2027	4,778	2020-2023	6,174	2020-2022

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
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Current derivative assets		$33		$16		$23		$12		$10		$4
Non-current derivative assets	15		11		11		10		4		1
Current derivative liabilities	6		19		2		9		4		10
Non-current derivative liabilities	13		19		6		9		7		10

WPL [Member]

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

As of September 30, 2020, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):

	FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	14,365	2020-2021	218,581	2020-2028	8,151	2020-2023	6,174	2020-2022
IPL	5,401	2020-2021	114,747	2020-2028	3,373	2020-2023	—	—
WPL	8,964	2020-2021	103,834	2020-2027	4,778	2020-2023	6,174	2020-2022

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
	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Current derivative assets		$33		$16		$23		$12		$10		$4
Non-current derivative assets	15		11		11		10		4		1
Current derivative liabilities	6		19		2		9		4		10
Non-current derivative liabilities	13		19		6		9		7		10

XML

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2020

Statement [Line Items]

Fair Value Measurements

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

Alliant Energy	September 30, 2020										December 31, 2019
			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		$183		$183		$—		$—		$183		$5		$5		$—		$—		$5
Derivatives	48		—		17		31		48		27		—		5		22		27
Deferred proceeds	201		—		—		201		201		188		—		—		188		188
Liabilities:
Derivatives	19		—		18		1		19		38		—		37		1		38
Long-term debt (incl. current maturities)	6,581		—		7,849		2		7,851		6,190		—		6,918		2		6,920

IPL	September 30, 2020										December 31, 2019
			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		$183		$183		$—		$—		$183		$5		$5		$—		$—		$5
Derivatives	34		—		7		27		34		22		—		3		19		22
Deferred proceeds	201		—		—		201		201		188		—		—		188		188
Liabilities:
Derivatives	8		—		7		1		8		18		—		17		1		18
Long-term debt (incl. current maturities)	3,344		—		3,987		—		3,987		3,147		—		3,489		—		3,489

WPL	September 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Derivatives		$14		$—		$10		$4		$14		$5		$—		$2		$3		$5
Liabilities:
Derivatives	11		—		11		—		11		20		—		20		—		20
Long-term debt (incl. current maturities)	2,130		—		2,667		—		2,667		1,933		—		2,268		—		2,268

Fair Value Measurements Using Significant Unobservable Inputs

Information for Alliant Energy’s and IPL’s fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions). Such amounts for WPL were not material.

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2020			2019			2020		2019
Beginning balance, July 1		$36			$13			$194		$215
Total net gains included in changes in net assets (realized/unrealized)	—			13			—		—
Transfers out of Level 3	—			(1		)	—		—
Sales	(1		)	—			—		—
Settlements (a)	(5		)	(3		)	7		22
Ending balance, September 30		$30			$22			$201		$237
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 September 30		($1	)		$13			$—		$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2020			2019			2020		2019
Beginning balance, January 1		$21			$12			$188		$119
Total net gains included in changes in net assets (realized/unrealized)	8			7			—		—
Transfers out of Level 3	—			3			—		—
Purchases	14			14			—		—
Sales	(1		)	—			—		—
Settlements (a)	(12		)	(14		)	13		118
Ending balance, September 30		$30			$22			$201		$237
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30		$8			$10			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2020			2019			2020		2019
Beginning balance, July 1		$32			$9			$194		$215
Total net gains (losses) included in changes in net assets (realized/unrealized)	(1		)	12			—		—
Transfers out of Level 3	—			(1		)	—		—
Sales	(1		)	—			—		—
Settlements (a)	(4		)	(2		)	7		22
Ending balance, September 30		$26			$18			$201		$237
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 September 30		($1	)		$12			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2020			2019			2020		2019
Beginning balance, January 1		$18			$9			$188		$119
Total net gains included in changes in net assets (realized/unrealized)	7			9			—		—
Transfers out of Level 3	—			2			—		—
Purchases	11			9			—		—
Sales	(1		)	—			—		—
Settlements (a)	(9		)	(11		)	13		118
Ending balance, September 30		$26			$18			$201		$237
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30		$7			$10			$—		$—

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

Fair Value Of Net Derivative Assets

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

	Alliant Energy				IPL				WPL
	Excluding FTRs		FTRs		Excluding FTRs		FTRs		Excluding FTRs		FTRs
September 30, 2020		$18		$12		$17		$9		$1		$3
December 31, 2019	15		7		14		5		1		2

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	September 30, 2020										December 31, 2019
			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		$183		$183		$—		$—		$183		$5		$5		$—		$—		$5
Derivatives	48		—		17		31		48		27		—		5		22		27
Deferred proceeds	201		—		—		201		201		188		—		—		188		188
Liabilities:
Derivatives	19		—		18		1		19		38		—		37		1		38
Long-term debt (incl. current maturities)	6,581		—		7,849		2		7,851		6,190		—		6,918		2		6,920

IPL	September 30, 2020										December 31, 2019
			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		$183		$183		$—		$—		$183		$5		$5		$—		$—		$5
Derivatives	34		—		7		27		34		22		—		3		19		22
Deferred proceeds	201		—		—		201		201		188		—		—		188		188
Liabilities:
Derivatives	8		—		7		1		8		18		—		17		1		18
Long-term debt (incl. current maturities)	3,344		—		3,987		—		3,987		3,147		—		3,489		—		3,489

WPL	September 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Derivatives		$14		$—		$10		$4		$14		$5		$—		$2		$3		$5
Liabilities:
Derivatives	11		—		11		—		11		20		—		20		—		20
Long-term debt (incl. current maturities)	2,130		—		2,667		—		2,667		1,933		—		2,268		—		2,268

Fair Value Measurements Using Significant Unobservable Inputs

Information for Alliant Energy’s and IPL’s fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions). Such amounts for WPL were not material.

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2020			2019			2020		2019
Beginning balance, July 1		$36			$13			$194		$215
Total net gains included in changes in net assets (realized/unrealized)	—			13			—		—
Transfers out of Level 3	—			(1		)	—		—
Sales	(1		)	—			—		—
Settlements (a)	(5		)	(3		)	7		22
Ending balance, September 30		$30			$22			$201		$237
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 September 30		($1	)		$13			$—		$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2020			2019			2020		2019
Beginning balance, January 1		$21			$12			$188		$119
Total net gains included in changes in net assets (realized/unrealized)	8			7			—		—
Transfers out of Level 3	—			3			—		—
Purchases	14			14			—		—
Sales	(1		)	—			—		—
Settlements (a)	(12		)	(14		)	13		118
Ending balance, September 30		$30			$22			$201		$237
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30		$8			$10			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2020			2019			2020		2019
Beginning balance, July 1		$32			$9			$194		$215
Total net gains (losses) included in changes in net assets (realized/unrealized)	(1		)	12			—		—
Transfers out of Level 3	—			(1		)	—		—
Sales	(1		)	—			—		—
Settlements (a)	(4		)	(2		)	7		22
Ending balance, September 30		$26			$18			$201		$237
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 September 30		($1	)		$12			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2020			2019			2020		2019
Beginning balance, January 1		$18			$9			$188		$119
Total net gains included in changes in net assets (realized/unrealized)	7			9			—		—
Transfers out of Level 3	—			2			—		—
Purchases	11			9			—		—
Sales	(1		)	—			—		—
Settlements (a)	(9		)	(11		)	13		118
Ending balance, September 30		$26			$18			$201		$237
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30		$7			$10			$—		$—

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

Fair Value Of Net Derivative Assets

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

	Alliant Energy				IPL				WPL
	Excluding FTRs		FTRs		Excluding FTRs		FTRs		Excluding FTRs		FTRs
September 30, 2020		$18		$12		$17		$9		$1		$3
December 31, 2019	15		7		14		5		1		2

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	September 30, 2020										December 31, 2019
			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		$183		$183		$—		$—		$183		$5		$5		$—		$—		$5
Derivatives	48		—		17		31		48		27		—		5		22		27
Deferred proceeds	201		—		—		201		201		188		—		—		188		188
Liabilities:
Derivatives	19		—		18		1		19		38		—		37		1		38
Long-term debt (incl. current maturities)	6,581		—		7,849		2		7,851		6,190		—		6,918		2		6,920

IPL	September 30, 2020										December 31, 2019
			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		$183		$183		$—		$—		$183		$5		$5		$—		$—		$5
Derivatives	34		—		7		27		34		22		—		3		19		22
Deferred proceeds	201		—		—		201		201		188		—		—		188		188
Liabilities:
Derivatives	8		—		7		1		8		18		—		17		1		18
Long-term debt (incl. current maturities)	3,344		—		3,987		—		3,987		3,147		—		3,489		—		3,489

WPL	September 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Derivatives		$14		$—		$10		$4		$14		$5		$—		$2		$3		$5
Liabilities:
Derivatives	11		—		11		—		11		20		—		20		—		20
Long-term debt (incl. current maturities)	2,130		—		2,667		—		2,667		1,933		—		2,268		—		2,268

Fair Value Of Net Derivative Assets

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

	Alliant Energy				IPL				WPL
	Excluding FTRs		FTRs		Excluding FTRs		FTRs		Excluding FTRs		FTRs
September 30, 2020		$18		$12		$17		$9		$1		$3
December 31, 2019	15		7		14		5		1		2

XML

Commitments And Contingencies (Tables)

9 Months Ended

Sep. 30, 2020

Commitments and Contingencies [Line Items]

Other Purchase Commitments

At September 30, 2020, related minimum future commitments were as follows (in millions):

	Alliant Energy		IPL		WPL
Natural gas		$983		$508		$475
Coal (a)	125		70		55
Other (b)	111		49		31
		$1,219		$627		$561

(a) Corporate Services has historically entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. Such commitments were assigned to IPL and WPL based on information available as of September 30, 2020 regarding expected future usage, which is subject to change.

(b)

Includes individual commitments incurred during the normal course of business that exceeded $1 million at September 30, 2020.

MGP Site Estimated Future Costs And Recorded Liabilities

At September 30, 2020, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At September 30, 2020, such amounts for WPL were not material.

	Alliant Energy				IPL
Range of estimated future costs		$12	-	$29		$9	-	$24
Current and non-current environmental liabilities	16				13

IPL [Member]

Commitments and Contingencies [Line Items]

Other Purchase Commitments

At September 30, 2020, related minimum future commitments were as follows (in millions):

	Alliant Energy		IPL		WPL
Natural gas		$983		$508		$475
Coal (a)	125		70		55
Other (b)	111		49		31
		$1,219		$627		$561

(a) Corporate Services has historically entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. Such commitments were assigned to IPL and WPL based on information available as of September 30, 2020 regarding expected future usage, which is subject to change.

(b)

Includes individual commitments incurred during the normal course of business that exceeded $1 million at September 30, 2020.

MGP Site Estimated Future Costs And Recorded Liabilities

At September 30, 2020, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At September 30, 2020, such amounts for WPL were not material.

	Alliant Energy				IPL
Range of estimated future costs		$12	-	$29		$9	-	$24
Current and non-current environmental liabilities	16				13

WPL [Member]

Commitments and Contingencies [Line Items]

Other Purchase Commitments

At September 30, 2020, related minimum future commitments were as follows (in millions):

	Alliant Energy		IPL		WPL
Natural gas		$983		$508		$475
Coal (a)	125		70		55
Other (b)	111		49		31
		$1,219		$627		$561

(a) Corporate Services has historically entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. Such commitments were assigned to IPL and WPL based on information available as of September 30, 2020 regarding expected future usage, which is subject to change.

(b)

Includes individual commitments incurred during the normal course of business that exceeded $1 million at September 30, 2020.

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Segments Of Business (Tables)

9 Months Ended

Sep. 30, 2020

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 September 30, 2020
Revenues		$852		$42			$10		$904		$16		$920
Operating income (loss)	251		(1		)	1		251		21		272
Net income attributable to Alliant Energy common shareowners								221		25		246
Three Months Ended September 30, 2019
Revenues		$916		$42			$11		$969		$21		$990
Operating income (loss)	284		(5		)	3		282		8		290
Net income attributable to Alliant Energy common shareowners								217		9		226

Alliant Energy									ATC Holdings,		Alliant
	Utility								Non-Utility,		Energy
	Electric		Gas		Other		Total		Parent and Other		Consolidated
	(in millions)
Nine Months Ended September 30, 2020
Revenues		$2,257		$253		$32		$2,542		$57		$2,599
Operating income	549		48		5		602		26		628
Net income attributable to Alliant Energy common shareowners							510		40		550
Nine Months Ended September 30, 2019
Revenues		$2,350		$323		$33		$2,706		$62		$2,768
Operating income	543		47		5		595		22		617
Net income attributable to Alliant Energy common shareowners							422		24		446

IPL	Electric		Gas			Other		Total
	(in millions)
Three Months Ended September 30, 2020
Revenues		$519		$24			$10		$553
Operating income	159		1			2		162
Net income available for common stock								148
Three Months Ended September 30, 2019
Revenues		$561		$25			$11		$597
Operating income (loss)	175		(4		)	3		174
Net income available for common stock								141
Nine Months Ended September 30, 2020
Revenues		$1,332		$141			$31		$1,504
Operating income	308		34			5		347
Net income available for common stock								290
Nine Months Ended September 30, 2019
Revenues		$1,373		$188			$32		$1,593
Operating income	291		26			5		322
Net income available for common stock								239

WPL	Electric		Gas			Other			Total
	(in millions)
Three Months Ended September 30, 2020
Revenues		$333		$18			$—			$351
Operating income (loss)	92		(2		)	(1		)	89
Net income									73
Three Months Ended September 30, 2019
Revenues		$355		$17			$—			$372
Operating income (loss)	109		(1		)	—			108
Net income									76
Nine Months Ended September 30, 2020
Revenues		$925		$112			$1			$1,038
Operating income	241		14			—			255
Net income									220
Nine Months Ended September 30, 2019
Revenues		$977		$135			$1			$1,113
Operating income	252		21			—			273
Net income									183

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 September 30, 2020
Revenues		$852		$42			$10		$904		$16		$920
Operating income (loss)	251		(1		)	1		251		21		272
Net income attributable to Alliant Energy common shareowners								221		25		246
Three Months Ended September 30, 2019
Revenues		$916		$42			$11		$969		$21		$990
Operating income (loss)	284		(5		)	3		282		8		290
Net income attributable to Alliant Energy common shareowners								217		9		226

Alliant Energy									ATC Holdings,		Alliant
	Utility								Non-Utility,		Energy
	Electric		Gas		Other		Total		Parent and Other		Consolidated
	(in millions)
Nine Months Ended September 30, 2020
Revenues		$2,257		$253		$32		$2,542		$57		$2,599
Operating income	549		48		5		602		26		628
Net income attributable to Alliant Energy common shareowners							510		40		550
Nine Months Ended September 30, 2019
Revenues		$2,350		$323		$33		$2,706		$62		$2,768
Operating income	543		47		5		595		22		617
Net income attributable to Alliant Energy common shareowners							422		24		446

IPL	Electric		Gas			Other		Total
	(in millions)
Three Months Ended September 30, 2020
Revenues		$519		$24			$10		$553
Operating income	159		1			2		162
Net income available for common stock								148
Three Months Ended September 30, 2019
Revenues		$561		$25			$11		$597
Operating income (loss)	175		(4		)	3		174
Net income available for common stock								141
Nine Months Ended September 30, 2020
Revenues		$1,332		$141			$31		$1,504
Operating income	308		34			5		347
Net income available for common stock								290
Nine Months Ended September 30, 2019
Revenues		$1,373		$188			$32		$1,593
Operating income	291		26			5		322
Net income available for common stock								239

WPL	Electric		Gas			Other			Total
	(in millions)
Three Months Ended September 30, 2020
Revenues		$333		$18			$—			$351
Operating income (loss)	92		(2		)	(1		)	89
Net income									73
Three Months Ended September 30, 2019
Revenues		$355		$17			$—			$372
Operating income (loss)	109		(1		)	—			108
Net income									76
Nine Months Ended September 30, 2020
Revenues		$925		$112			$1			$1,038
Operating income	241		14			—			255
Net income									220
Nine Months Ended September 30, 2019
Revenues		$977		$135			$1			$1,113
Operating income	252		21			—			273
Net income									183

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 September 30, 2020
Revenues		$852		$42			$10		$904		$16		$920
Operating income (loss)	251		(1		)	1		251		21		272
Net income attributable to Alliant Energy common shareowners								221		25		246
Three Months Ended September 30, 2019
Revenues		$916		$42			$11		$969		$21		$990
Operating income (loss)	284		(5		)	3		282		8		290
Net income attributable to Alliant Energy common shareowners								217		9		226

Alliant Energy									ATC Holdings,		Alliant
	Utility								Non-Utility,		Energy
	Electric		Gas		Other		Total		Parent and Other		Consolidated
	(in millions)
Nine Months Ended September 30, 2020
Revenues		$2,257		$253		$32		$2,542		$57		$2,599
Operating income	549		48		5		602		26		628
Net income attributable to Alliant Energy common shareowners							510		40		550
Nine Months Ended September 30, 2019
Revenues		$2,350		$323		$33		$2,706		$62		$2,768
Operating income	543		47		5		595		22		617
Net income attributable to Alliant Energy common shareowners							422		24		446

IPL	Electric		Gas			Other		Total
	(in millions)
Three Months Ended September 30, 2020
Revenues		$519		$24			$10		$553
Operating income	159		1			2		162
Net income available for common stock								148
Three Months Ended September 30, 2019
Revenues		$561		$25			$11		$597
Operating income (loss)	175		(4		)	3		174
Net income available for common stock								141
Nine Months Ended September 30, 2020
Revenues		$1,332		$141			$31		$1,504
Operating income	308		34			5		347
Net income available for common stock								290
Nine Months Ended September 30, 2019
Revenues		$1,373		$188			$32		$1,593
Operating income	291		26			5		322
Net income available for common stock								239

WPL	Electric		Gas			Other			Total
	(in millions)
Three Months Ended September 30, 2020
Revenues		$333		$18			$—			$351
Operating income (loss)	92		(2		)	(1		)	89
Net income									73
Three Months Ended September 30, 2019
Revenues		$355		$17			$—			$372
Operating income (loss)	109		(1		)	—			108
Net income									76
Nine Months Ended September 30, 2020
Revenues		$925		$112			$1			$1,038
Operating income	241		14			—			255
Net income									220
Nine Months Ended September 30, 2019
Revenues		$977		$135			$1			$1,113
Operating income	252		21			—			273
Net income									183

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Related Parties (Tables)

9 Months Ended

Sep. 30, 2020

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 nine months ended September 30 were as follows (in millions):

	IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months
	2020		2019		2020		2019		2020		2019		2020		2019
Corporate Services billings		$53		$47		$134		$137		$41		$36		$108		$104
Sales credited	10		23		35		50		—		2		4		6
Purchases billed	110		93		248		251		39		32		79		91

Net Intercompany Payables

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

	IPL		WPL
	September 30, 2020	December 31, 2019	September 30, 2020	December 31, 2019
Net payables to Corporate Services	$119	$112	$77	$85

Related Amounts Billed Between Parties

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

	Three Months				Nine Months
	2020		2019		2020		2019
ATC billings to WPL		$27		$28		$80		$82
WPL billings to ATC	2		3		8		10

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 nine months ended September 30 were as follows (in millions):

	IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months
	2020		2019		2020		2019		2020		2019		2020		2019
Corporate Services billings		$53		$47		$134		$137		$41		$36		$108		$104
Sales credited	10		23		35		50		—		2		4		6
Purchases billed	110		93		248		251		39		32		79		91

Net Intercompany Payables

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

	IPL		WPL
	September 30, 2020	December 31, 2019	September 30, 2020	December 31, 2019
Net payables to Corporate Services	$119	$112	$77	$85

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 nine months ended September 30 were as follows (in millions):

	IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months
	2020		2019		2020		2019		2020		2019		2020		2019
Corporate Services billings		$53		$47		$134		$137		$41		$36		$108		$104
Sales credited	10		23		35		50		—		2		4		6
Purchases billed	110		93		248		251		39		32		79		91

Net Intercompany Payables

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

	IPL		WPL
	September 30, 2020	December 31, 2019	September 30, 2020	December 31, 2019
Net payables to Corporate Services	$119	$112	$77	$85

Related Amounts Billed Between Parties

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

	Three Months				Nine Months
	2020		2019		2020		2019
ATC billings to WPL		$27		$28		$80		$82
WPL billings to ATC	2		3		8		10

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Summary Of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Money market fund investments	$ 183	$ 5
Money market fund investments interest rate, percentage	0.10%
IPL [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Money market fund investments	$ 183	5
Money market fund investments interest rate, percentage	0.10%
Credit Losses ASU [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New accounting standard, cumulative effect adjustment to retained earnings, pre-tax		12
New accounting standard, cumulative effect adjustment to retained earnings, after-tax		$ 9

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Regulatory Matters (Narrative) (Details) $ in Millions	1 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2020 USD ($)	Aug. 31, 2020 customer	Jun. 30, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2020 USD ($)
Regulatory Matters [Line Items]
Credits issued to customers				$ (72)	$ (12)
Electric transmission cost recovery [Member] | IPL [Member]
Regulatory Matters [Line Items]
Credits issued to customers			$ 42
DAEC PPA [Member]
Regulatory Matters [Line Items]
Buyout payment	$ 110
PPA term amendment	5 years
Derecho windstorm [Member]
Regulatory Matters [Line Items]
Net regulatory liability, derecho windstorm	$ 7			7
Derecho windstorm [Member] | IPL [Member]
Regulatory Matters [Line Items]
Number of customers without power, derecho windstorm (number of customers) | customer		250,000
Derecho windstorm repair and rebuilding costs	$ 130			$ 130
Derecho windstorm [Member] | Forecast [Member] | IPL [Member]
Regulatory Matters [Line Items]
Derecho windstorm repair and rebuilding costs						$ 140

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Regulatory Matters (Regulatory Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Regulatory Assets [Line Items]
Regulatory assets	$ 1,836	$ 1,845
Tax-related [Member]
Regulatory Assets [Line Items]
Regulatory assets	877	818
Pension and OPEB costs [Member]
Regulatory Assets [Line Items]
Regulatory assets	492	524
Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	118	134
Asset retirement obligations [Member]
Regulatory Assets [Line Items]
Regulatory assets	115	112
IPL's DAEC PPA amendment [Member]
Regulatory Assets [Line Items]
Regulatory assets	110	108
Derivatives [Member]
Regulatory Assets [Line Items]
Regulatory assets	20	39
Emission allowances [Member]
Regulatory Assets [Line Items]
Regulatory assets	19	21
Other [Member]
Regulatory Assets [Line Items]
Regulatory assets	85	89
IPL [Member]
Regulatory Assets [Line Items]
Regulatory assets	1,418	1,400
IPL [Member] | Tax-related [Member]
Regulatory Assets [Line Items]
Regulatory assets	829	777
IPL [Member] | Pension and OPEB costs [Member]
Regulatory Assets [Line Items]
Regulatory assets	247	263
IPL [Member] | Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	79	88
IPL [Member] | Asset retirement obligations [Member]
Regulatory Assets [Line Items]
Regulatory assets	79	76
IPL [Member] | IPL's DAEC PPA amendment [Member]
Regulatory Assets [Line Items]
Regulatory assets	110	108
IPL [Member] | Derivatives [Member]
Regulatory Assets [Line Items]
Regulatory assets	8	18
IPL [Member] | Emission allowances [Member]
Regulatory Assets [Line Items]
Regulatory assets	19	21
IPL [Member] | Other [Member]
Regulatory Assets [Line Items]
Regulatory assets	47	49
WPL [Member]
Regulatory Assets [Line Items]
Regulatory assets	418	445
WPL [Member] | Tax-related [Member]
Regulatory Assets [Line Items]
Regulatory assets	48	41
WPL [Member] | Pension and OPEB costs [Member]
Regulatory Assets [Line Items]
Regulatory assets	245	261
WPL [Member] | Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	39	46
WPL [Member] | Asset retirement obligations [Member]
Regulatory Assets [Line Items]
Regulatory assets	36	36
WPL [Member] | Derivatives [Member]
Regulatory Assets [Line Items]
Regulatory assets	12	21
WPL [Member] | Other [Member]
Regulatory Assets [Line Items]
Regulatory assets	$ 38	$ 40

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Regulatory Matters (Regulatory Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Regulatory Liabilities [Line Items]
Regulatory liabilities	$ 1,351	$ 1,424
Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	746	836
Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	371	388
Electric transmission cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	62	88
Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	40	20
WPL's West Riverside liquidated damages [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	36	0
Commodity cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	22	24
WPL's earnings sharing mechanism [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	22	22
Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	52	46
IPL [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	691	715
IPL [Member] | Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	334	351
IPL [Member] | Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	241	257
IPL [Member] | Electric transmission cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	30	51
IPL [Member] | Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	27	17
IPL [Member] | Commodity cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	19	9
IPL [Member] | Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	40	30
WPL [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	660	709
WPL [Member] | Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	412	485
WPL [Member] | Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	130	131
WPL [Member] | Electric transmission cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	32	37
WPL [Member] | Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	13	3
WPL [Member] | WPL's West Riverside liquidated damages [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	36
WPL [Member] | Commodity cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	3	15
WPL [Member] | WPL's earnings sharing mechanism [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	22	22
WPL [Member] | Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	$ 12	$ 16

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Receivables (Narrative) (Details) - Receivables Sold [Member] - IPL [Member] $ in Millions	Sep. 30, 2020 USD ($)
Receivables [Line Items]
Available capacity	$ 109
Outstanding receivables past due	$ 27

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Receivables (Details of Accounts Receivable) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Receivables [Line Items]
Customer	$ 95	$ 92
Unbilled utility revenues	62	82
Deferred proceeds	201	188
Other	54	47
Allowance for expected credit losses	(13)	(7)
Accounts receivable, less allowance for expected credit losses	399	402
IPL [Member]
Receivables [Line Items]
Customer	0	0
Unbilled utility revenues	0	0
Deferred proceeds	201	188
Other	20	16
Allowance for expected credit losses	(2)	(1)
Accounts receivable, less allowance for expected credit losses	219	203
WPL [Member]
Receivables [Line Items]
Customer	86	84
Unbilled utility revenues	62	82
Other	33	31
Allowance for expected credit losses	(11)	(6)
Accounts receivable, less allowance for expected credit losses	$ 170	$ 191

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Receivables (Maximum And Average Outstanding Cash Proceeds) (Details) - IPL [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Maximum [Member]
Receivables [Line Items]
Outstanding aggregate cash proceeds (based on daily outstanding balances)	$ 1	$ 103	$ 96	$ 108
Average [Member]
Receivables [Line Items]
Outstanding aggregate cash proceeds (based on daily outstanding balances)	$ 1	$ 45	$ 12	$ 43

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Receivables (Receivables Sold Under The Agreement) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Receivables [Line Items]
Fair value of deferred proceeds	$ 201	$ 188
IPL [Member]
Receivables [Line Items]
Fair value of deferred proceeds	201	188
Receivables Sold [Member] | IPL [Member]
Receivables [Line Items]
Customer accounts receivable	148	125
Unbilled utility revenues	67	95
Other receivables	0	1
Receivables sold to third party	215	221
Less: cash proceeds	1	27
Deferred proceeds	214	194
Less: allowance for expected credit losses	13	6
Fair value of deferred proceeds	$ 201	$ 188

XML

Receivables (Additional Attributes Of Receivables Sold Under The Agreement) (Details) - IPL [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Receivables [Line Items]
Collections	$ 561	$ 592	$ 1,555	$ 1,636
Write-offs, net of recoveries	$ 1	$ 3	$ 4	$ 11

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Investments (Unconsolidated Equity Investments) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule of Equity Method Investments [Line Items]
Equity income from unconsolidated investments, net	$ (15)	$ (12)	$ (46)	$ (35)
ATC Holdings [Member]
Schedule of Equity Method Investments [Line Items]
Equity income from unconsolidated investments, net	(11)	(11)	(36)	(30)
Non-utility wind farm in Oklahoma [Member]
Schedule of Equity Method Investments [Line Items]
Equity income from unconsolidated investments, net	(2)	0	(6)	(3)
Other [Member]
Schedule of Equity Method Investments [Line Items]
Equity income from unconsolidated investments, net	$ (2)	$ (1)	$ (4)	$ (2)

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Common Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended			9 Months Ended
	Nov. 30, 2019	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Common Equity [Line Items]
Proceeds from issuance of common stock, net		$ 6		$ 125	$ 241	$ 185
Equity Forward Agreements [Member]
Common Equity [Line Items]
Common stock to be issued, equity forward agreements (in shares)	4,275,127
Forward sales price (in dollars per share)	$ 52.235		$ 51.98
Proceeds from issuance of common stock, net			$ 222
Common stock issued during the period, equity forward agreements (in shares)			4,275,127		4,275,127

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Common Equity (Common Share Activity) (Details) - shares	3 Months Ended	9 Months Ended
	Mar. 31, 2020	Sep. 30, 2020
Common Stock Oustanding [Roll Forward]
Shares outstanding, January 1, 2020 (in shares)	245,022,800	245,022,800
Shareowner Direct Plan (in shares)		364,531
Equity-based compensation plans (in shares)		98,205
Shares outstanding, September 30, 2020 (in shares)		249,760,663
Equity Forward Agreements [Member]
Common Stock Oustanding [Roll Forward]
Equity forward agreements (in shares)	4,275,127	4,275,127

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Common Equity (Changes in Shareowners' Equity) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance			$ 5,205
Beginning balance	$ 5,748	$ 4,900	5,405	$ 4,786
Net income attributable to common shareowners	246	226	550	446
Net income	249	229	558	454
Common stock dividends	(94)	(85)	(281)	(253)
Equity forward settlements and Shareowner Direct Plan issuances	6	125	241	185
Equity-based compensation plans and other	3	3	5	6
Adoption of new accounting standard, net of tax			(9)
Other comprehensive loss, net of tax			(2)	(1)
Ending balance	5,709		5,709
Ending balance	$ 5,909	$ 5,169	$ 5,909	$ 5,169
Common stock dividends (in dollars per share)	$ 0.38	$ 0.355	$ 1.14	$ 1.065
Common Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	$ 2	$ 2	$ 2	$ 2
Ending balance	2	2	2	2
Additional Paid-in Capital [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	2,683	2,109	2,446	2,046
Equity forward settlements and Shareowner Direct Plan issuances	6	125	241	185
Equity-based compensation plans and other	4	3	6	6
Ending balance	2,693	2,237	2,693	2,237
Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	2,874	2,598	2,766	2,546
Net income attributable to common shareowners	246	226	550	446
Common stock dividends	(94)	(85)	(281)	(253)
Ending balance	3,026	2,739	3,026	2,739
Accumulated Other Comprehensive Income (Loss) [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	(1)	1	1	2
Other comprehensive loss, net of tax			(2)	(1)
Ending balance	(1)	1	(1)	1
Shares in Deferred Compensation Trust [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	(10)	(10)	(10)	(10)
Equity-based compensation plans and other	(1)		(1)
Ending balance	(11)	(10)	(11)	(10)
Cumulative Preferred Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	200	200	200	200
Ending balance	200	200	200	200
IPL [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance			3,272
Beginning balance	3,671	3,345	3,472	3,231
Net income attributable to common shareowners	148	141	290	239
Net income	151	144	298	247
Common stock dividends	(59)	(42)	(177)	(126)
Capital contributions from parent	170		345	100
Ending balance	3,730		3,730
Ending balance	3,930	3,444	3,930	3,444
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	2,523	2,323	2,348	2,223
Capital contributions from parent	170		345	100
Ending balance	2,693	2,323	2,693	2,323
IPL [Member] | Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	915	789	891	775
Net income attributable to common shareowners	148	141	290	239
Common stock dividends	(59)	(42)	(177)	(126)
Ending balance	1,004	888	1,004	888
IPL [Member] | Cumulative Preferred Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	200	200	200	200
Ending balance	200	200	200	200
WPL [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance			2,364
Beginning balance	2,452	2,185	2,364	2,150
Net income	73	76	220	183
Common stock dividends	(43)	(36)	(127)	(108)
Capital contributions from parent		100	25	100
Ending balance	2,482		2,482
Ending balance	2,482	2,325	2,482	2,325
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	1,459	1,309	1,434	1,309
Capital contributions from parent		100	25	100
Ending balance	1,459	1,409	1,459	1,409
WPL [Member] | Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	927	810	864	775
Net income	73	76	220	183
Common stock dividends	(43)	(36)	(127)	(108)
Ending balance	$ 957	$ 850	957	$ 850
Credit Losses ASU [Member] | Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Adoption of new accounting standard, net of tax			$ (9)

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Debt (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended			9 Months Ended
	Jun. 30, 2020	Apr. 30, 2020	Mar. 31, 2020	Sep. 30, 2020	Sep. 30, 2019
Debt [Line Items]
Payments to retire long-term debt				$ 654	$ 253
IPL [Member]
Debt [Line Items]
Payments to retire long-term debt				200	0
WPL [Member]
Debt [Line Items]
Payments to retire long-term debt				$ 150	$ 250
Term Loan Credit Agreement [Member] | Term Loan Credit Agreement Through March 2022 [Member] | Alliant Energy Finance, LLC [Member]
Debt [Line Items]
Proceeds from issuance of long-term debt			$ 300
Interest rate, percent				1.00%
Term Loan Credit Agreement [Member] | Term Loan Credit Agreement Through April 2020 [Member] | Alliant Energy Finance, LLC [Member]
Debt [Line Items]
Payments to retire long-term debt			$ 300
Debentures [Member] | 3.65% debenture, due 2050 [Member] | WPL [Member]
Debt [Line Items]
Proceeds from issuance of long-term debt		$ 350
Interest rate, percent				3.65%
Debentures [Member] | 4.6% debenture, due 2020 [Member] | WPL [Member]
Debt [Line Items]
Interest rate, percent	4.60%
Payments to retire long-term debt	$ 150
Senior Debentures [Member] | 2.3% senior debenture, due 2030 [Member] | IPL [Member]
Debt [Line Items]
Proceeds from issuance of long-term debt	$ 400
Interest rate, percent				2.30%
Senior Debentures [Member] | 3.65% senior debenture, due 2020 [Member] | IPL [Member]
Debt [Line Items]
Interest rate, percent	3.65%
Payments to retire long-term debt	$ 200

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Debt (Credit Facilities) (Details) $ in Millions	Sep. 30, 2020 USD ($)
Debt [Line Items]
Amount outstanding	$ 422
Weighted average interest rates	0.20%
Available credit facility capacity	$ 578
IPL [Member]
Debt [Line Items]
Amount outstanding	0
Available credit facility capacity	250
WPL [Member]
Debt [Line Items]
Amount outstanding	$ 139
Weighted average interest rates	0.10%
Available credit facility capacity	$ 161

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Debt (Other Short-Term Borrowings) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Debt [Line Items]
Maximum amount outstanding (based on daily outstanding balances)	$ 422	$ 472	$ 463	$ 601
Average amount outstanding (based on daily outstanding balances)	$ 252	$ 400	$ 252	$ 476
Weighted average interest rates	0.20%	2.50%	1.10%	2.60%
IPL [Member]
Debt [Line Items]
Maximum amount outstanding (based on daily outstanding balances)	$ 0	$ 0	$ 8	$ 50
Average amount outstanding (based on daily outstanding balances)	0	0	$ 0	$ 0
Weighted average interest rates			0.50%	2.80%
WPL [Member]
Debt [Line Items]
Maximum amount outstanding (based on daily outstanding balances)	139	90	$ 212	$ 195
Average amount outstanding (based on daily outstanding balances)	$ 83	$ 27	$ 86	$ 102
Weighted average interest rates	0.20%	2.30%	1.20%	2.50%

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Revenue (Disaggregation of Revenues) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 920	$ 990	$ 2,599	$ 2,768
Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	852	916	2,257	2,350
Electric [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	328	332	845	840
Electric [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	210	231	556	583
Electric [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	241	264	648	686
Electric [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	47	50	127	137
Electric [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	26	39	81	104
Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	42	42	253	323
Gas [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	22	20	146	187
Gas [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10	10	70	90
Gas [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2	3	8	10
Gas [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8	9	29	36
Other Utility [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10	11	32	33
Other Utility [Member] | Steam [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8	9	27	27
Other Utility [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2	2	5	6
Non-utility and Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16	21	57	62
Non-utility and Other [Member] | Transportation and other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16	21	57	62
IPL [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	553	597	1,504	1,593
IPL [Member] | Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	519	561	1,332	1,373
IPL [Member] | Electric [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	189	196	472	470
IPL [Member] | Electric [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	142	158	371	386
IPL [Member] | Electric [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	149	158	384	392
IPL [Member] | Electric [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	17	18	44	49
IPL [Member] | Electric [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	22	31	61	76
IPL [Member] | Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	24	25	141	188
IPL [Member] | Gas [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	12	12	79	109
IPL [Member] | Gas [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6	6	38	50
IPL [Member] | Gas [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	2	5	7
IPL [Member] | Gas [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5	5	19	22
IPL [Member] | Other Utility [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10	11	31	32
IPL [Member] | Other Utility [Member] | Steam [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8	9	27	27
IPL [Member] | Other Utility [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2	2	4	5
WPL [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	351	372	1,038	1,113
WPL [Member] | Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	333	355	925	977
WPL [Member] | Electric [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	139	136	373	370
WPL [Member] | Electric [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	68	73	185	197
WPL [Member] | Electric [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	92	106	264	294
WPL [Member] | Electric [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	30	32	83	88
WPL [Member] | Electric [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4	8	20	28
WPL [Member] | Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	18	17	112	135
WPL [Member] | Gas [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10	8	67	78
WPL [Member] | Gas [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4	4	32	40
WPL [Member] | Gas [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	1	3	3
WPL [Member] | Gas [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3	4	10	14
WPL [Member] | Other Utility [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	1	1
WPL [Member] | Other Utility [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 0	$ 0	$ 1	$ 1

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Income Taxes (Schedule Of Effective Income Tax Rates) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Effective Tax Rate [Line Items]
Overall income tax rate	(9.00%)	9.00%	(9.00%)	10.00%
IPL [Member]
Effective Tax Rate [Line Items]
Overall income tax rate	(14.00%)	5.00%	(14.00%)	4.00%
WPL [Member]
Effective Tax Rate [Line Items]
Overall income tax rate	(7.00%)	18.00%	(8.00%)	18.00%

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Income Taxes (Summary Of Tax Credit Carryforwards) (Details) $ in Millions	Sep. 30, 2020 USD ($)
Federal [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	$ 371
Tax credits, carryforward amount	446
Federal [Member] | IPL [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	343
Tax credits, carryforward amount	252
Federal [Member] | WPL [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	3
Tax credits, carryforward amount	173
State [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	623
State [Member] | IPL [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	10
State [Member] | WPL [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	$ 2

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Benefit Plans (Narrative) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($) shares
Defined Benefit Plan Disclosure [Line Items]
Unrecognized compensation cost	$ 7
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	$ 4
WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized compensation cost	$ 3
Omnibus Incentive Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Shares included in diluted earnings per share (in shares) | shares	276,070

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Benefit Plans (Defined Benefit Pension And Other Postretirement Benefits Plans) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3	$ 2	$ 8	$ 7
Interest cost	10	13	32	37
Expected return on plan assets	(17)	(15)	(52)	(45)
Amortization of actuarial loss	9	9	26	27
Settlement losses	0	0	4	0
Total	5	9	18	26
OPEB Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	3	3
Interest cost	2	2	5	6
Expected return on plan assets	(1)	(1)	(4)	(4)
Amortization of actuarial loss	0	1	2	2
Settlement losses	0	0	0	0
Total	2	3	6	7
IPL [Member] | Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	1	5	4
Interest cost	5	6	15	17
Expected return on plan assets	(8)	(7)	(24)	(21)
Amortization of actuarial loss	4	4	11	12
Total	3	4	7	12
IPL [Member] | OPEB Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	1	1
Interest cost	1	1	2	3
Expected return on plan assets	(1)	(1)	(3)	(3)
Amortization of actuarial loss	0	1	1	1
Total	0	1	1	2
WPL [Member] | Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	3	3
Interest cost	5	5	14	16
Expected return on plan assets	(8)	(6)	(23)	(20)
Amortization of actuarial loss	4	4	12	13
Total	2	4	6	12
WPL [Member] | OPEB Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	1	1
Interest cost	1	1	2	3
Expected return on plan assets	(1)	0	(1)	(1)
Amortization of actuarial loss	1	0	2	1
Total	$ 1	$ 1	$ 4	$ 4

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Benefit Plans (Recognized Compensation Expense And Income Tax Benefits) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Compensation expense	$ 5	$ 8	$ 10	$ 16
Income tax benefits	1	2	3	4
IPL [Member]
Compensation expense	3	4	6	9
Income tax benefits	1	1	2	2
WPL [Member]
Compensation expense	2	3	4	6
Income tax benefits	$ 0	$ 1	$ 1	$ 2

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Benefit Plans (Summary Of Equity-based Compensation Plans Grants) (Details)	9 Months Ended
	Sep. 30, 2020 $ / shares shares
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants (in shares/units) | shares	55,303
Weighted average grant date fair value (in dollars per share/unit) | $ / shares	$ 64.04
Performance Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants (in shares/units) | shares	55,303
Weighted average grant date fair value (in dollars per share/unit) | $ / shares	$ 59.47
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants (in shares/units) | shares	60,284
Weighted average grant date fair value (in dollars per share/unit) | $ / shares	$ 59.49

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Asset Retirement Obligations (Reconciliation Of Changes In Asset Retirement Obligations) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($)
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance, January 1	$ 196
Revisions in estimated cash flows	1
Liabilities settled	(7)
Liabilities incurred	38
Accretion expense	5
Balance, September 30	233
IPL [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance, January 1	134
Revisions in estimated cash flows	0
Liabilities settled	(5)
Liabilities incurred	38
Accretion expense	4
Balance, September 30	$ 171

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Derivative Instruments (Notional Amounts Of Derivative Instruments) (Details) - Commodity [Member] gal in Thousands, T in Thousands, MWh in Thousands, Dekatherms in Thousands	9 Months Ended
	Sep. 30, 2020 Dekatherms MWh T gal
FTRs (MWhs) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs) | MWh	14,365
FTRs (MWhs) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs) | MWh	5,401
FTRs (MWhs) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs) | MWh	8,964
Natural Gas (Dths) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Dths) | Dekatherms	218,581
Natural Gas (Dths) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Dths) | Dekatherms	114,747
Natural Gas (Dths) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Dths) | Dekatherms	103,834
Coal (Tons) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Tons) | T	8,151
Coal (Tons) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Tons) | T	3,373
Coal (Tons) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Tons) | T	4,778
Diesel Fuel (Gallons) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Gallons) | gal	6,174
Diesel Fuel (Gallons) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Gallons) | gal	0
Diesel Fuel (Gallons) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Gallons) | gal	6,174

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Derivative Instruments (Fair Value Of Financial Instruments) (Details) - Commodity Contracts [Member] - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Current derivative assets	$ 33	$ 16
Non-current derivative assets	15	11
Current derivative liabilities	6	19
Non-current derivative liabilities	13	19
IPL [Member]
Derivatives, Fair Value [Line Items]
Current derivative assets	23	12
Non-current derivative assets	11	10
Current derivative liabilities	2	9
Non-current derivative liabilities	6	9
WPL [Member]
Derivatives, Fair Value [Line Items]
Current derivative assets	10	4
Non-current derivative assets	4	1
Current derivative liabilities	4	10
Non-current derivative liabilities	$ 7	$ 10

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Fair Value Measurements (Fair Value Measurements) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Assets:
Money market fund investments	$ 183	$ 5
Deferred proceeds	201	188
Liabilities:
Long-term debt (incl. current maturities)	7,851	6,920
IPL [Member]
Assets:
Money market fund investments	183	5
Deferred proceeds	201	188
Liabilities:
Long-term debt (incl. current maturities)	3,987	3,489
WPL [Member]
Liabilities:
Long-term debt (incl. current maturities)	2,667	2,268
Commodity Contracts [Member]
Assets:
Derivatives	48	27
Liabilities:
Derivatives	19	38
Commodity Contracts [Member] | IPL [Member]
Assets:
Derivatives	34	22
Liabilities:
Derivatives	8	18
Commodity Contracts [Member] | WPL [Member]
Assets:
Derivatives	14	5
Liabilities:
Derivatives	11	20
Level 1 [Member]
Assets:
Money market fund investments	183	5
Deferred proceeds	0	0
Liabilities:
Long-term debt (incl. current maturities)	0	0
Level 1 [Member] | IPL [Member]
Assets:
Money market fund investments	183	5
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 2 [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	0	0
Liabilities:
Long-term debt (incl. current maturities)	7,849	6,918
Level 2 [Member] | IPL [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	0	0
Liabilities:
Long-term debt (incl. current maturities)	3,987	3,489
Level 2 [Member] | WPL [Member]
Liabilities:
Long-term debt (incl. current maturities)	2,667	2,268
Level 2 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	17	5
Liabilities:
Derivatives	18	37
Level 2 [Member] | Commodity Contracts [Member] | IPL [Member]
Assets:
Derivatives	7	3
Liabilities:
Derivatives	7	17
Level 2 [Member] | Commodity Contracts [Member] | WPL [Member]
Assets:
Derivatives	10	2
Liabilities:
Derivatives	11	20
Level 3 [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	201	188
Liabilities:
Long-term debt (incl. current maturities)	2	2
Level 3 [Member] | IPL [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	201	188
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	31	22
Liabilities:
Derivatives	1	1
Level 3 [Member] | Commodity Contracts [Member] | IPL [Member]
Assets:
Derivatives	27	19
Liabilities:
Derivatives	1	1
Level 3 [Member] | Commodity Contracts [Member] | WPL [Member]
Assets:
Derivatives	4	3
Liabilities:
Derivatives	0	0
Carrying Amount [Member]
Assets:
Money market fund investments	183	5
Deferred proceeds	201	188
Liabilities:
Long-term debt (incl. current maturities)	6,581	6,190
Carrying Amount [Member] | IPL [Member]
Assets:
Money market fund investments	183	5
Deferred proceeds	201	188
Liabilities:
Long-term debt (incl. current maturities)	3,344	3,147
Carrying Amount [Member] | WPL [Member]
Liabilities:
Long-term debt (incl. current maturities)	2,130	1,933
Carrying Amount [Member] | Commodity Contracts [Member]
Assets:
Derivatives	48	27
Liabilities:
Derivatives	19	38
Carrying Amount [Member] | Commodity Contracts [Member] | IPL [Member]
Assets:
Derivatives	34	22
Liabilities:
Derivatives	8	18
Carrying Amount [Member] | Commodity Contracts [Member] | WPL [Member]
Assets:
Derivatives	14	5
Liabilities:
Derivatives	$ 11	$ 20

XML

Fair Value Measurements (Fair Value Measurements Using Significant Unobservable Inputs) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Commodity Contracts [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 36	$ 13	$ 21	$ 12
Total net gains (losses) included in changes in net assets (realized/unrealized)	0	13	8	7
Transfers out of Level 3	0	(1)	0	3
Purchases			14	14
Sales	(1)	0	(1)	0
Settlements	(5)	(3)	(12)	(14)
Ending balance	30	22	30	22
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 September 30	(1)	13	8	10
Commodity Contracts [Member] | IPL [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	32	9	18	9
Total net gains (losses) included in changes in net assets (realized/unrealized)	(1)	12	7	9
Transfers out of Level 3	0	(1)	0	2
Purchases			11	9
Sales	(1)	0	(1)	0
Settlements	(4)	(2)	(9)	(11)
Ending balance	26	18	26	18
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 September 30	(1)	12	7	10
Deferred Proceeds [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	194	215	188	119
Total net gains (losses) included in changes in net assets (realized/unrealized)	0	0	0	0
Transfers out of Level 3	0	0	0	0
Purchases			0	0
Sales	0	0	0	0
Settlements	7	22	13	118
Ending balance	201	237	201	237
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 September 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	194	215	188	119
Total net gains (losses) included in changes in net assets (realized/unrealized)	0	0	0	0
Transfers out of Level 3	0	0	0	0
Purchases			0	0
Sales	0	0	0	0
Settlements	7	22	13	118
Ending balance	201	237	201	237
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 September 30	$ 0	$ 0	$ 0	$ 0

XML

Fair Value Measurements (Fair Value Of Net Derivative Assets (Liabilities)) (Details) - Commodity Contracts [Member] - USD ($) $ in Millions	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	$ 30	$ 36	$ 21	$ 22	$ 13	$ 12
Excluding Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	18		15
Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	12		7
IPL [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	26	$ 32	18	$ 18	$ 9	$ 9
IPL [Member] | Excluding Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	17		14
IPL [Member] | Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	9		5
WPL [Member] | Excluding Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	1		1
WPL [Member] | Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	$ 3		$ 2

XML

Commitments And Contingencies (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	May 31, 2020	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019	Mar. 31, 2020
Commitments and Contingencies [Line Items]
Minimum future commitments			$ 1,219
IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments			627
WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments			561
Capital Purchase Commitment [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments			21
Capital Purchase Commitment [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments			18
Indemnification Agreement [Member]
Commitments and Contingencies [Line Items]
Obligations, maximum		$ 74	74
Indemnification Agreement [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Obligations, maximum		17	17
Indemnification Agreement [Member] | Purchased Power [Member]
Commitments and Contingencies [Line Items]
Obligations, maximum		17	$ 17
Credit Losses ASU [Member]
Commitments and Contingencies [Line Items]
New accounting standard, cumulative effect adjustment to retained earnings, pre-tax				$ 12
Whiting Petroleum Affiliate [Member]
Commitments and Contingencies [Line Items]
Partnership share, percent			6.00%
Obligations, maximum		68	$ 68
Credit loss liability		5	5		$ 20
Credit loss expense		$ 15	7
Whiting Petroleum Affiliate [Member] | Credit Losses ASU [Member]
Commitments and Contingencies [Line Items]
New accounting standard, cumulative effect adjustment to retained earnings, pre-tax				$ 12
FederalEnergyRegulatoryCommission [Member]
Commitments and Contingencies [Line Items]
MISO base return on equity, percentage	10.02%			9.88%
FederalEnergyRegulatoryCommission [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Refunds related to MISO base return on equity complaints			15
FederalEnergyRegulatoryCommission [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Refunds related to MISO base return on equity complaints			$ 5

XML

Commitments And Contingencies (Other Purchase Commitments) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($)
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 1,219
Individual commitments incurred	1
IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	627
Individual commitments incurred	1
WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	561
Individual commitments incurred	1
Natural gas [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	983
Natural gas [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	508
Natural gas [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	475
Coal [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	125
Coal [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	70
Coal [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	55
Other [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	111
Other [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	49
Other [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 31

XML

Commitments And Contingencies (MPG Site Estimated Future Costs And Recorded Liabilities) (Details) - Natural Gas Processing Plant [Member] $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($)
Commitments and Contingencies [Line Items]
Current and non-current environmental liabilities	$ 16
IPL [Member]
Commitments and Contingencies [Line Items]
Current and non-current environmental liabilities	13
Minimum [Member]
Commitments and Contingencies [Line Items]
Range of estimated future costs	12
Minimum [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Range of estimated future costs	9
Maximum [Member]
Commitments and Contingencies [Line Items]
Range of estimated future costs	29
Maximum [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Range of estimated future costs	$ 24

XML

Segments Of Business (Schedule Of Segments Of Business) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenues	$ 920	$ 990	$ 2,599	$ 2,768
Operating income (loss)	272	290	628	617
Net income attributable to common shareowners	246	226	550	446
Net income	249	229	558	454
IPL [Member]
Segment Reporting Information [Line Items]
Revenues	553	597	1,504	1,593
Operating income (loss)	162	174	347	322
Net income attributable to common shareowners	148	141	290	239
Net income	151	144	298	247
WPL [Member]
Segment Reporting Information [Line Items]
Revenues	351	372	1,038	1,113
Operating income (loss)	89	108	255	273
Net income	73	76	220	183
Electric [Member]
Segment Reporting Information [Line Items]
Revenues	852	916	2,257	2,350
Operating income (loss)	251	284	549	543
Electric [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	519	561	1,332	1,373
Operating income (loss)	159	175	308	291
Electric [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	333	355	925	977
Operating income (loss)	92	109	241	252
Gas [Member]
Segment Reporting Information [Line Items]
Revenues	42	42	253	323
Operating income (loss)	(1)	(5)	48	47
Gas [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	24	25	141	188
Operating income (loss)	1	(4)	34	26
Gas [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	18	17	112	135
Operating income (loss)	(2)	(1)	14	21
Other Utility [Member]
Segment Reporting Information [Line Items]
Revenues	10	11	32	33
Operating income (loss)	1	3	5	5
Other Utility [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	10	11	31	32
Operating income (loss)	2	3	5	5
Other Utility [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	0	0	1	1
Operating income (loss)	(1)	0	0	0
Utility Business [Member]
Segment Reporting Information [Line Items]
Revenues	904	969	2,542	2,706
Operating income (loss)	251	282	602	595
Net income attributable to common shareowners	221	217	510	422
Non-Utility [Member] | ATC Holdings, Non-Utility, Parent and Other [Member]
Segment Reporting Information [Line Items]
Revenues	16	21	57	62
Operating income (loss)	21	8	26	22
Net income attributable to common shareowners	$ 25	$ 9	$ 40	$ 24

XML

Related Parties (Narrative) (Details) - ATC LLC [Member] - Equity Method Investee [Member] - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
WPL Owed ATC LLC [Member]
Related Party Transactions [Line Items]
Net amounts owed		$ 9	$ 9
WPL [Member]
Related Party Transactions [Line Items]
Receipt of construction deposits	$ 46

XML

Related Parties (Service Agreements) (Details) - Corporate Services [Member] - Subsidiary of Common Parent [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Corporate Services Billings [Member] | IPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	$ 53	$ 47	$ 134	$ 137
Corporate Services Billings [Member] | WPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	41	36	108	104
Sales Credited [Member] | IPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	10	23	35	50
Sales Credited [Member] | WPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	0	2	4	6
Purchases Billed [Member] | IPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	110	93	248	251
Purchases Billed [Member] | WPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	$ 39	$ 32	$ 79	$ 91

XML

Related Parties (Net Intercompany Payables) (Details) - Subsidiary of Common Parent [Member] - Corporate Services [Member] - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
IPL [Member]
Related Party Transactions [Line Items]
Net amounts owed	$ 119	$ 112
WPL [Member]
Related Party Transactions [Line Items]
Net amounts owed	$ 77	$ 85

XML

Related Parties (Amounts Billed Between Parties) (Details) - ATC LLC [Member] - Equity Method Investee [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
ATC Billings To WPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	$ 27	$ 28	$ 80	$ 82
WPL Billings To ATC [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	$ 2	$ 3	$ 8	$ 10