Table of Contents

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
     
FORM 10-Q
     
☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the quarterly period ended March 31, 20182019
 
or
 
☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the transition period from                    to                    

alliantenergylogo.jpg
Commission
File Number
 
Name of Registrant, State of Incorporation,
Address of Principal Executive Offices and Telephone Number
 
IRS Employer
Identification Number
1-9894 ALLIANT ENERGY CORPORATION 39-1380265
  (a Wisconsin corporation)  
  4902 N. Biltmore Lane  
  Madison, Wisconsin 53718  
  Telephone (608) 458-3311  
   
1-4117 INTERSTATE POWER AND LIGHT COMPANY 42-0331370
  (an Iowa corporation)  
  Alliant Energy Tower  
  Cedar Rapids, Iowa 52401  
  Telephone (319) 786-4411  
   
0-337 WISCONSIN POWER AND LIGHT COMPANY 39-0714890
  (a Wisconsin corporation)  
  4902 N. Biltmore Lane  
  Madison, Wisconsin 53718  
  Telephone (608) 458-3311  
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.

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.    Yes ☒  No ☐
Indicate by check mark whether the registrants have submitted electronically and posted on their corporate Web site, if any, every Interactive Data File required to be submitted and posted 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 and post such files).    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.
 Large Accelerated Filer  Accelerated Filer  Non-accelerated Filer  Smaller Reporting Company Emerging Growth Company
Alliant Energy Corporation☒           
Interstate Power and Light Company      ☒     
Wisconsin Power and Light 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. ☐
Indicate by check mark whether the registrants are shell companies (as defined in Rule 12b-2 of the Exchange Act).    Yes ☐  No ☒
Securities registered pursuant to Section 12(b) of the Act:
Title of Each ClassTrading SymbolName of Each Exchange on Which Registered
Alliant Energy CorporationCommon Stock, $0.01 Par ValueLNTNasdaq Global Select Market
Interstate Power and Light Company5.100% Series D Cumulative Perpetual Preferred Stock, $0.01 Par ValueIPLDPNasdaq Global Select Market
Number of shares outstanding of each class of common stock as of March 31, 2018:2019:
Alliant Energy CorporationCommon stock, $0.01 par value, 231,481,828237,394,409 shares outstanding
  
Interstate Power and Light CompanyCommon stock, $2.50 par value, 13,370,788 shares outstanding (all of which are owned beneficially and of record by Alliant Energy Corporation)
  
Wisconsin Power and Light CompanyCommon stock, $5 par value, 13,236,601 shares outstanding (all of which are owned beneficially and of record by Alliant Energy Corporation)


Table of Contents

TABLE OF CONTENTS
 Page
Definitions
1
Forward-looking Statements
1
Part I. Financial Information
3
Item 1. Condensed Consolidated Financial Statements (Unaudited)
3
Alliant Energy Corporation
3
Interstate Power and Light Company
6
Wisconsin Power and Light Company
9
Combined Notes to Condensed Consolidated Financial Statements
12
1. Summary of Significant Accounting Policies
12
2. Regulatory Matters
1413
3. Property, Plant and EquipmentReceivables
1514
4. ReceivablesInvestments and Acquisitions
1514
5. InvestmentsCommon Equity
1614
6. Common EquityDebt
16
7. DebtLeases
16
8. Revenues
1718
9. Income Taxes
18
10. Benefit Plans
1918
11. Asset Retirement Obligations
20
12. Derivative Instruments
20
13. Fair Value Measurements
21
12. Derivative Instruments14. Commitments and Contingencies
22
13. Commitments and Contingencies
23
14.15. Segments of Business
2524
15.16. Related Parties
2625
Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations
2725
Item 3. Quantitative and Qualitative Disclosures About Market Risk
3430
Item 4. Controls and Procedures
3431
Part II. Other Information
3531
Item 1A. Risk Factors
3531
Item 2. Unregistered Sales of Equity Securities and Use of Proceeds
3531
Item 6. Exhibits
3532
Signatures
3632

Table of Contents

DEFINITIONS
The following abbreviations or acronyms used in this Form 10-Qreport are defined below:
Abbreviation or AcronymDefinitionAbbreviation or AcronymDefinition
20172018 Form 10-KCombined Annual Report on Form 10-K filed by Alliant Energy, IPL and WPL for the year ended Dec. 31, 20172018Fuel-relatedElectric production fuel and purchased power
AEFAlliant Energy Finance, LLCGAAPU.S. generally accepted accounting principles
Alliant EnergyAlliant Energy CorporationIPLInterstate Power and Light Company
ATCAmerican Transmission Company LLCIUBIowa Utilities Board
AEFATC HoldingsAlliant Energy Finance,Interest in American Transmission Company LLC and ATC Holdco LLCMDAManagement’s Discussion and Analysis of Financial Condition and Results of Operations
AFUDCCorporate ServicesAllowance for funds used during constructionAlliant Energy Corporate Services, Inc.MISOMidcontinent Independent System Operator, Inc.
AlliantDAECDuane Arnold EnergyAlliant Energy CorporationMWMegawatt
ATCAmerican Transmission Company LLC CenterMWhMegawatt-hour
ATC HoldingsDthInterest in American Transmission Company LLC and ATC Holdco LLCDekathermN/ANot applicable
Corporate ServicesEGUAlliant Energy Corporate Services, Inc.Electric generating unitNote(s)Combined Notes to Condensed Consolidated Financial Statements
DthEPADekathermNOxNitrogen oxide
EGUElectric generating unitU.S. Environmental Protection AgencyOPEBOther postretirement benefits
EPAEPSU.S. Environmental Protection AgencyEarnings per weighted average common sharePSCWPPAPublic Service Commission of WisconsinPurchased power agreement
FERCFederal Tax ReformFederal Energy Regulatory CommissionTax Cuts and Jobs ActRiversideU.S.Riverside Energy CenterUnited States of America
Financial StatementsCondensed Consolidated Financial StatementsSCRSelective catalytic reduction
FTRFinancial transmission rightTax ReformTax Cuts and Jobs Act
Fuel-relatedElectric production fuel and purchased powerU.S.United States of America
GAAPU.S. generally accepted accounting principlesWhiting PetroleumWhiting Petroleum Corporation
IPLFTRInterstate Power and Light CompanyFinancial transmission rightWPLWisconsin 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, earning a return on rate base additions and the recovery of and/or the return on costs, including fuel costs, operating costs, transmission costs, environmental compliance and remediation costs, deferred expenditures, deferred tax assets, tax expense, capital expenditures, and remaining costs related to EGUs that may be permanently closed, 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 energy, tax, financial and health care legislation, and regulatory agency orders;
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;
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;

 1 
Table of Contents

issues associated with environmental remediation and environmental compliance, including compliance with the Consent Decree between WPL, the EPAall environmental and the Sierra Club, the Consent Decree between IPL, the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa,emissions permits, the Coal Combustion Residuals Rule, the Clean Power Plan, future changes in environmental laws and regulations, including the EPA’s regulations for carbon dioxide emissions reductions from new and existing fossil-fueled EGUs, and litigation associated with environmental requirements;
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 impact of the economy in IPL’s and WPL’s service territories and the resulting impacts on sales volumes, margins and the ability to collect unpaid bills;
the ability to complete construction of wind projects within the cost caps set by regulators and to meet all requirements to qualify for the full level of production 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;
changes in the price of transmission services and the ability to recover the cost of transmission services in a timely manner;
developments that adversely impact the ability to implement the strategic plan;
ability to obtain regulatory approval for wind projects with acceptable conditions, to acquire sufficient transmission-ready wind sites, to complete construction within the cost caps set by regulators and to meet all requirements to qualify for the full level of production tax credits;
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;
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 storms or natural disasters inmay have on Alliant Energy’s, IPL’s and WPL’s service territories may have on their operations and recovery of costs associated with restoration activities;activities, or on the operations of Alliant Energy’s investments;
any material post-closing adjustments related to any past asset divestitures, including the sales of IPL’s Minnesota electric and natural gas assets, and Whiting Petroleum, which could result from, among other things, indemnification agreements, warranties, parental guarantees or litigation;
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, 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 due to further 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 adjustments made to deferred tax assets and liabilities from changes in the tax laws;
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
•
factors listed in MDA and Risk Factors in Item 1A in the 20172018 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 
Table of Contents

PART I. FINANCIAL INFORMATION
ITEM 1. CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED)
ALLIANT ENERGY CORPORATION
CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)
For the Three MonthsFor the Three Months
Ended March 31,Ended March 31,
2018 20172019 2018
(in millions, except per share amounts)(in millions, except per share amounts)
Revenues:      
Electric utility
$708.7
 
$677.6

$743.4
 
$708.7
Gas utility185.6
 154.3
215.8
 185.6
Other utility13.2
 11.7
11.1
 13.2
Non-utility8.8
 10.3
16.9
 8.8
Total revenues916.3
 853.9
987.2
 916.3
Operating expenses:      
Electric production fuel and purchased power203.2
 207.8
218.4
 203.2
Electric transmission service126.4
 124.7
123.0
 126.4
Cost of gas sold111.2
 92.2
121.6
 111.2
Other operation and maintenance162.4
 148.6
181.2
 162.4
Depreciation and amortization120.4
 107.0
136.9
 120.4
Taxes other than income taxes27.0
 26.4
29.3
 27.0
Total operating expenses750.6
 706.7
810.4
 750.6
Operating income165.7
 147.2
176.8
 165.7
Other (income) and deductions:      
Interest expense59.2
 52.3
66.3
 59.2
Equity income from unconsolidated investments, net(21.3) (11.5)(10.9) (21.3)
Allowance for funds used during construction(14.9) (17.0)(25.4) (14.9)
Other2.4
 4.2
4.0
 2.4
Total other (income) and deductions25.4
 28.0
34.0
 25.4
Income from continuing operations before income taxes140.3
 119.2
Income before income taxes142.8
 140.3
Income taxes16.8
 17.6
15.1
 16.8
Income from continuing operations, net of tax123.5
 101.6
Income from discontinued operations, net of tax—
 1.4
Net income123.5
 103.0
127.7
 123.5
Preferred dividend requirements of Interstate Power and Light Company2.6
 2.6
2.6
 2.6
Net income attributable to Alliant Energy common shareowners
$120.9
 
$100.4

$125.1
 
$120.9
Weighted average number of common shares outstanding (basic and diluted)231.4
 227.6
Earnings per weighted average common share attributable to Alliant Energy common shareowners (basic and diluted):
   
Income from continuing operations, net of tax
$0.52
 
$0.43
Income from discontinued operations, net of tax—
 0.01
Net income
$0.52
 
$0.44
Amounts attributable to Alliant Energy common shareowners:   
Income from continuing operations, net of tax
$120.9
 
$99.0
Income from discontinued operations, net of tax—
 1.4
Net income
$120.9
 
$100.4
Dividends declared per common share
$0.335
 
$0.315
Weighted average number of common shares outstanding (basic)236.5
 231.4
Weighted average number of common shares outstanding (diluted)236.6
 231.4
Earnings per weighted average common share attributable to Alliant Energy common shareowners (basic and diluted)

$0.53
 
$0.52

TheRefer to accompanying Combined Notes to Condensed Consolidated Financial Statements are an integral part of these statements.Statements.

 3 
Table of Contents

ALLIANT ENERGY CORPORATION
CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)
March 31,
2018		 December 31,
2017		March 31,
2019		 December 31,
2018
(in millions, except per
share and share amounts)
(in millions, except per
share and share amounts)
ASSETS      
Current assets:      
Cash and cash equivalents
$19.1
 
$27.9

$10.1
 
$20.9
Accounts receivable, less allowance for doubtful accounts343.2
 482.8
417.9
 350.4
Production fuel, at weighted average cost76.7
 72.3
47.0
 61.4
Gas stored underground, at weighted average cost16.3
 44.5
15.9
 49.0
Materials and supplies, at weighted average cost109.8
 105.6
105.1
 101.4
Regulatory assets74.9
 84.3
65.8
 79.8
Other85.9
 87.7
153.4
 122.2
Total current assets725.9
 905.1
815.2
 785.1
Property, plant and equipment, net11,439.6
 11,234.5
12,665.2
 12,462.4
Investments:      
ATC Holdings275.5
 274.2
295.0
 293.6
Other139.2
 121.9
138.6
 137.7
Total investments414.7
 396.1
433.6
 431.3
Other assets:      
Regulatory assets1,589.2
 1,582.4
1,726.6
 1,657.5
Deferred charges and other72.4
 69.7
72.8
 89.7
Total other assets1,661.6
 1,652.1
1,799.4
 1,747.2
Total assets
$14,241.8
 
$14,187.8

$15,713.4
 
$15,426.0
LIABILITIES AND EQUITY      
Current liabilities:      
Current maturities of long-term debt
$855.7
 
$855.7

$256.5
 
$256.5
Commercial paper336.4
 320.2
514.7
 441.2
Other short-term borrowings95.0
 95.0
Accounts payable363.1
 477.3
387.7
 543.3
Regulatory liabilities172.2
 140.0
179.8
 142.7
Other251.1
 260.8
249.0
 260.4
Total current liabilities2,073.5
 2,149.0
1,587.7
 1,644.1
Long-term debt, net (excluding current portion)4,056.8
 4,010.6
5,362.2
 5,246.3
Other liabilities:      
Deferred tax liabilities1,511.6
 1,478.4
1,642.0
 1,603.1
Regulatory liabilities1,365.7
 1,357.2
1,302.6
 1,350.5
Pension and other benefit obligations488.9
 504.0
493.6
 509.1
Other313.8
 306.4
442.9
 287.2
Total other liabilities3,680.0
 3,646.0
3,881.1
 3,749.9
Commitments and contingencies (Note 13)


 

Commitments and contingencies (Note 14)


 

Equity:      
Alliant Energy Corporation common equity:      
Common stock - $0.01 par value - 480,000,000 shares authorized; 231,481,828 and 231,348,646 shares outstanding2.3
 2.3
Common stock - $0.01 par value - 480,000,000 shares authorized; 237,394,409 and 236,063,279 shares outstanding2.4
 2.4
Additional paid-in capital1,851.4
 1,845.5
2,100.0
 2,045.5
Retained earnings2,389.4
 2,346.0
2,587.3
 2,545.9
Accumulated other comprehensive loss(0.5) (0.5)
Shares in deferred compensation trust - 458,639 and 463,365 shares at a weighted average cost of $24.17 and $23.91 per share(11.1) (11.1)
Accumulated other comprehensive income2.4
 1.7
Shares in deferred compensation trust - 375,542 and 384,580 shares at a weighted average cost of $25.93 and $25.60 per share(9.7) (9.8)
Total Alliant Energy Corporation common equity4,231.5
 4,182.2
4,682.4
 4,585.7
Cumulative preferred stock of Interstate Power and Light Company200.0
 200.0
200.0
 200.0
Total equity4,431.5
 4,382.2
4,882.4
 4,785.7
Total liabilities and equity
$14,241.8
 
$14,187.8

$15,713.4
 
$15,426.0

TheRefer to accompanying Combined Notes to Condensed Consolidated Financial Statements are an integral part of these statements.Statements.

 4 
Table of Contents

ALLIANT ENERGY CORPORATION
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)
For the Three MonthsFor the Three Months
Ended March 31,Ended March 31,
2018 20172019 2018
(in millions)(in millions)
Cash flows from operating activities:      
Net income
$123.5
 
$103.0

$127.7
 
$123.5
Adjustments to reconcile net income to net cash flows from operating activities:      
Depreciation and amortization120.4
 107.0
136.9
 120.4
Deferred tax expense and tax credits17.6
 22.7
21.7
 17.6
Other(14.8) (7.6)(10.1) (14.8)
Other changes in assets and liabilities:      
Accounts receivable(147.6) (143.2)(121.6) (80.6)
Gas stored underground28.2
 25.4
33.1
 28.2
Regulatory assets(3.4) (40.6)
Derivative assets11.0
 28.1
Accounts payable(59.6) (41.3)(42.7) (59.6)
Regulatory liabilities34.2
 14.2
14.1
 34.2
Deferred income taxes14.9
 32.8
Other(35.1) 18.5
22.0
 (12.6)
Net cash flows from operating activities89.3
 119.0
181.1
 156.3
Cash flows used for investing activities:      
Construction and acquisition expenditures:      
Utility business(335.2) (268.9)(374.0) (335.2)
Other(20.3) (22.6)(32.1) (20.3)
Cash receipts on sold receivables284.3
 214.7
53.4
 217.3
Other(14.0) (10.4)(12.1) (14.0)
Net cash flows used for investing activities(85.2) (87.2)(364.8) (152.2)
Cash flows used for financing activities:   
Cash flows from (used for) financing activities:   
Common stock dividends(77.5) (71.5)(83.7) (77.5)
Proceeds from issuance of common stock, net54.6
 6.3
Net change in commercial paper62.1
 58.7
188.5
 62.1
Other5.6
 (17.1)16.6
 (0.7)
Net cash flows used for financing activities(9.8) (29.9)
Net increase (decrease) in cash, cash equivalents and restricted cash(5.7) 1.9
Net cash flows from (used for) financing activities176.0
 (9.8)
Net decrease in cash, cash equivalents and restricted cash(7.7) (5.7)
Cash, cash equivalents and restricted cash at beginning of period33.9
 13.1
25.5
 33.9
Cash, cash equivalents and restricted cash at end of period
$28.2
 
$15.0

$17.8
 
$28.2
Supplemental cash flows information:      
Cash paid during the period for:   
Cash (paid) refunded during the period for:   
Interest, net of capitalized interest
($54.2) 
($51.8)
($62.9) 
($54.2)
Income taxes, net
$—
 
($2.3)
$6.8
 
$—
Significant non-cash investing and financing activities:      
Accrued capital expenditures
$144.9
 
$139.3

$167.5
 
$144.9
Beneficial interest obtained in exchange for securitized accounts receivable
$120.9
 
$149.0

$178.3
 
$120.9

TheRefer to accompanying Combined Notes to Condensed Consolidated Financial Statements are an integral part of these statements.Statements.

 5 
Table of Contents

INTERSTATE POWER AND LIGHT COMPANY
CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)
For the Three MonthsFor the Three Months
Ended March 31,Ended March 31,
2018 20172019 2018
(in millions)(in millions)
Revenues:      
Electric utility
$405.7
 
$356.2

$419.8
 
$405.7
Gas utility108.1
 83.1
124.6
 108.1
Steam and other12.0
 11.2
10.7
 12.0
Total revenues525.8
 450.5
555.1
 525.8
Operating expenses:      
Electric production fuel and purchased power114.6
 109.5
128.9
 114.6
Electric transmission service90.8
 81.7
87.7
 90.8
Cost of gas sold60.6
 47.8
63.3
 60.6
Other operation and maintenance105.5
 93.2
108.0
 105.5
Depreciation and amortization64.8
 53.6
77.1
 64.8
Taxes other than income taxes13.9
 13.4
16.6
 13.9
Total operating expenses450.2
 399.2
481.6
 450.2
Operating income75.6
 51.3
73.5
 75.6
Other (income) and deductions:      
Interest expense29.8
 27.7
29.4
 29.8
Allowance for funds used during construction(7.4) (14.3)(15.8) (7.4)
Other0.8
 1.8
1.9
 0.8
Total other (income) and deductions23.2
 15.2
15.5
 23.2
Income before income taxes52.4
 36.1
58.0
 52.4
Income tax expense (benefit)3.1
 (3.7)
Income taxes2.1
 3.1
Net income49.3
 39.8
55.9
 49.3
Preferred dividend requirements2.6
 2.6
2.6
 2.6
Earnings available for common stock
$46.7
 
$37.2

$53.3
 
$46.7
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.
TheRefer to accompanying Combined Notes to Condensed Consolidated Financial Statements are an integral part of these statements.Statements.

 6 
Table of Contents

INTERSTATE POWER AND LIGHT COMPANY
CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)
March 31,
2018		 December 31,
2017		March 31,
2019		 December 31,
2018
(in millions, except per
share and share amounts)
(in millions, except per
share and share amounts)
ASSETS  
Current assets:      
Cash and cash equivalents
$2.9
 
$3.6

$3.9
 
$9.7
Accounts receivable, less allowance for doubtful accounts145.9
 264.9
209.5
 153.5
Production fuel, at weighted average cost55.0
 52.4
31.2
 44.8
Gas stored underground, at weighted average cost3.6
 20.3
5.4
 26.1
Materials and supplies, at weighted average cost61.6
 60.6
56.9
 55.4
Regulatory assets38.1
 41.9
27.0
 39.2
Other23.2
 32.3
21.3
 43.1
Total current assets330.3
 476.0
355.2
 371.8
Property, plant and equipment, net6,088.5
 5,926.2
6,947.9
 6,781.5
Other assets:      
Regulatory assets1,192.8
 1,189.7
1,324.4
 1,239.8
Deferred charges and other16.2
 14.1
19.5
 18.3
Total other assets1,209.0
 1,203.8
1,343.9
 1,258.1
Total assets
$7,627.8
 
$7,606.0

$8,647.0
 
$8,411.4
LIABILITIES AND EQUITY  
Current liabilities:      
Current maturities of long-term debt
$350.0
 
$350.0
Commercial paper
$—
 
$50.4
Accounts payable183.2
 220.3
227.3
 304.9
Accounts payable to associated companies35.9
 50.1
Regulatory liabilities102.4
 69.7
107.3
 90.0
Other127.4
 137.6
150.3
 161.8
Total current liabilities798.9
 827.7
484.9
 607.1
Long-term debt, net (excluding current portion)2,102.2
 2,056.0
Long-term debt, net2,667.8
 2,552.3
Other liabilities:      
Deferred tax liabilities926.5
 910.7
970.9
 957.3
Regulatory liabilities674.9
 685.7
641.5
 664.9
Pension and other benefit obligations171.6
 173.8
174.6
 178.4
Other239.2
 242.4
365.3
 220.7
Total other liabilities2,012.2
 2,012.6
2,152.3
 2,021.3
Commitments and contingencies (Note 13)


 

Commitments and contingencies (Note 14)


 

Equity:      
Interstate Power and Light Company common equity:      
Common stock - $2.50 par value - 24,000,000 shares authorized; 13,370,788 shares outstanding33.4
 33.4
33.4
 33.4
Additional paid-in capital1,797.8
 1,797.8
2,322.8
 2,222.8
Retained earnings683.3
 678.5
785.8
 774.5
Total Interstate Power and Light Company common equity2,514.5
 2,509.7
3,142.0
 3,030.7
Cumulative preferred stock200.0
 200.0
200.0
 200.0
Total equity2,714.5
 2,709.7
3,342.0
 3,230.7
Total liabilities and equity
$7,627.8
 
$7,606.0

$8,647.0
 
$8,411.4

TheRefer to accompanying Combined Notes to Condensed Consolidated Financial Statements are anintegral part of these statements.Statements.

 7 
Table of Contents

INTERSTATE POWER AND LIGHT COMPANY
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)
For the Three MonthsFor the Three Months
Ended March 31,Ended March 31,
2018 20172019 2018
(in millions)(in millions)
Cash flows used for operating activities:   
Cash flows from operating activities:   
Net income
$49.3
 
$39.8

$55.9
 
$49.3
Adjustments to reconcile net income to net cash flows used for operating activities:   
Adjustments to reconcile net income to net cash flows from operating activities:   
Depreciation and amortization64.8
 53.6
77.1
 64.8
Other—
 3.1
(10.1) —
Other changes in assets and liabilities:      
Accounts receivable(166.7) (147.0)(112.6) (99.7)
Regulatory assets(3.3) (29.3)
Gas stored underground20.7
 16.7
Accounts payable(34.3) (24.7)(15.0) (34.3)
Regulatory liabilities21.7
 15.7
17.4
 21.7
Deferred income taxes11.2
 29.1
Other(7.9) 21.3
43.3
 (16.7)
Net cash flows used for operating activities(65.2) (38.4)
Cash flows from investing activities:   
Net cash flows from operating activities76.7
 1.8
Cash flows used for investing activities:   
Construction and acquisition expenditures(218.2) (127.6)(261.3) (218.2)
Cash receipts on sold receivables284.3
 214.7
53.4
 217.3
Other(10.5) (8.7)(13.9) (10.5)
Net cash flows from investing activities55.6
 78.4
Cash flows from (used for) financing activities:   
Net cash flows used for investing activities(221.8) (11.4)
Cash flows from financing activities:   
Common stock dividends(41.9) (39.1)(42.0) (41.9)
Capital contributions from parent100.0
 —
Net change in commercial paper45.9
 9.2
64.6
 45.9
Other4.9
 (9.3)17.0
 4.9
Net cash flows from (used for) financing activities8.9
 (39.2)
Net increase (decrease) in cash, cash equivalents and restricted cash(0.7) 0.8
Net cash flows from financing activities139.6
 8.9
Net decrease in cash, cash equivalents and restricted cash(5.5) (0.7)
Cash, cash equivalents and restricted cash at beginning of period7.2
 4.2
12.4
 7.2
Cash, cash equivalents and restricted cash at end of period
$6.5
 
$5.0

$6.9
 
$6.5
Supplemental cash flows information:      
Cash paid during the period for:   
Cash (paid) refunded during the period for:   
Interest
($28.2) 
($28.4)
($36.0) 
($28.2)
Income taxes, net
$—
 
($2.6)
$6.8
 
$—
Significant non-cash investing and financing activities:      
Accrued capital expenditures
$68.3
 
$44.2

$106.6
 
$68.3
Beneficial interest obtained in exchange for securitized accounts receivable
$120.9
 
$149.0

$178.3
 
$120.9

TheRefer to accompanying Combined Notes to Condensed Consolidated Financial Statements are an integral part of these statements.


Statements.

 8 
Table of Contents

WISCONSIN POWER AND LIGHT COMPANY
CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)
For the Three MonthsFor the Three Months
Ended March 31,Ended March 31,
2018 20172019 2018
(in millions)(in millions)
Revenues:      
Electric utility
$303.0
 
$321.4

$323.6
 
$303.0
Gas utility77.5
 71.2
91.2
 77.5
Other1.2
 0.5
0.4
 1.2
Total revenues381.7
 393.1
415.2
 381.7
Operating expenses:      
Electric production fuel and purchased power88.6
 98.3
89.5
 88.6
Electric transmission service35.6
 43.0
35.3
 35.6
Cost of gas sold50.6
 44.4
58.3
 50.6
Other operation and maintenance56.3
 54.4
63.5
 56.3
Depreciation and amortization54.6
 52.4
58.6
 54.6
Taxes other than income taxes12.0
 12.0
11.9
 12.0
Total operating expenses297.7
 304.5
317.1
 297.7
Operating income84.0
 88.6
98.1
 84.0
Other (income) and deductions:      
Interest expense24.7
 22.9
25.8
 24.7
Allowance for funds used during construction(7.5) (2.7)(9.6) (7.5)
Other1.1
 2.5
1.6
 1.1
Total other (income) and deductions18.3
 22.7
17.8
 18.3
Income before income taxes65.7
 65.9
80.3
 65.7
Income taxes11.7
 20.4
14.6
 11.7
Earnings available for common stock
$54.0
 
$45.5

$65.7
 
$54.0
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.
TheRefer to accompanying Combined Notes to Condensed Consolidated Financial Statements are an integral part of these statements.Statements.

 9 
Table of Contents

WISCONSIN POWER AND LIGHT COMPANY
CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)
March 31,
2018		 December 31,
2017		March 31,
2019		 December 31,
2018
(in millions, except per
share and share amounts)
(in millions, except per
share and share amounts)
ASSETS  
Current assets:      
Cash and cash equivalents
$3.7
 
$23.1

$3.4
 
$8.7
Accounts receivable, less allowance for doubtful accounts192.0
 212.2
198.7
 190.1
Production fuel, at weighted average cost21.7
 19.9
15.8
 16.6
Gas stored underground, at weighted average cost12.7
 24.2
10.5
 22.9
Materials and supplies, at weighted average cost44.9
 42.1
45.3
 42.9
Regulatory assets36.8
 42.4
38.8
 40.6
Other57.7
 54.7
103.5
 62.8
Total current assets369.5
 418.6
416.0
 384.6
Property, plant and equipment, net4,962.6
 4,917.9
5,322.8
 5,287.3
Other assets:      
Regulatory assets396.4
 392.7
402.2
 417.7
Deferred charges and other29.4
 27.3
24.0
 62.9
Total other assets425.8
 420.0
426.2
 480.6
Total assets
$5,757.9
 
$5,756.5

$6,165.0
 
$6,152.5
LIABILITIES AND EQUITY  
Current liabilities:      
Current maturities of long-term debt
$250.0
 
$250.0
Commercial paper
$30.6
 
$25.0
138.4
 105.5
Accounts payable134.6
 201.7
104.5
 180.9
Accounts payable to associated companies28.1
 22.2
Regulatory liabilities69.8
 70.3
72.5
 52.7
Other89.8
 77.0
112.5
 105.5
Total current liabilities352.9
 396.2
677.9
 694.6
Long-term debt, net1,833.7
 1,833.4
Long-term debt, net (excluding current portion)1,585.4
 1,584.9
Other liabilities:      
Deferred tax liabilities530.9
 522.4
601.0
 582.0
Regulatory liabilities690.8
 671.5
661.1
 685.6
Capital lease obligations - Sheboygan Falls Energy Facility65.8
 70.2
Finance lease obligations - Sheboygan Falls Energy Facility57.9
 60.0
Pension and other benefit obligations210.8
 213.7
214.2
 217.7
Other172.5
 167.6
188.3
 178.2
Total other liabilities1,670.8
 1,645.4
1,722.5
 1,723.5
Commitments and contingencies (Note 13)

 
Commitments and contingencies (Note 14)

 
Equity:      
Wisconsin Power and Light Company common equity:      
Common stock - $5 par value - 18,000,000 shares authorized; 13,236,601 shares outstanding66.2
 66.2
66.2
 66.2
Additional paid-in capital1,109.0
 1,109.0
1,309.0
 1,309.0
Retained earnings725.3
 706.3
804.0
 774.3
Total Wisconsin Power and Light Company common equity1,900.5
 1,881.5
2,179.2
 2,149.5
Total liabilities and equity
$5,757.9
 
$5,756.5

$6,165.0
 
$6,152.5

TheRefer to accompanying Combined Notes to Condensed Consolidated Financial Statements are an integral part of these statements.Statements.

 10 
Table of Contents

WISCONSIN POWER AND LIGHT COMPANY
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)
For the Three MonthsFor the Three Months
Ended March 31,Ended March 31,
2018 20172019 2018
(in millions)(in millions)
Cash flows from operating activities:      
Net income
$54.0
 
$45.5

$65.7
 
$54.0
Adjustments to reconcile net income to net cash flows from operating activities:      
Depreciation and amortization54.6
 52.4
58.6
 54.6
Deferred tax expense and tax credits6.7
 11.8
14.8
 6.7
Other(4.7) 2.6
(2.0) (4.7)
Other changes in assets and liabilities:      
Accounts receivable18.7
 13.3
(10.3) 18.7
Accounts payable(23.0) (25.5)(28.7) (23.0)
Other35.4
 45.5
24.1
 35.4
Net cash flows from operating activities141.7
 145.6
122.2
 141.7
Cash flows used for investing activities:      
Construction and acquisition expenditures(117.0) (141.3)(112.7) (117.0)
Other(11.7) (8.0)(7.6) (11.7)
Net cash flows used for investing activities(128.7) (149.3)(120.3) (128.7)
Cash flows from (used for) financing activities:   
Cash flows used for financing activities:   
Common stock dividends(35.0) (31.5)(36.0) (35.0)
Net change in commercial paper5.6
 38.9
32.9
 5.6
Other(1.9) (5.8)(3.3) (1.9)
Net cash flows from (used for) financing activities(31.3) 1.6
Net cash flows used for financing activities(6.4) (31.3)
Net decrease in cash, cash equivalents and restricted cash(18.3) (2.1)(4.5) (18.3)
Cash, cash equivalents and restricted cash at beginning of period24.2
 6.9
9.2
 24.2
Cash, cash equivalents and restricted cash at end of period
$5.9
 
$4.8

$4.7
 
$5.9
Supplemental cash flows information:      
Cash paid during the period for:      
Interest
($21.5) 
($21.9)
($22.5) 
($21.5)
Significant non-cash investing and financing activities:      
Accrued capital expenditures
$73.9
 
$90.5

$57.3
 
$73.9

TheRefer to accompanying Combined Notes to Condensed Consolidated Financial Statements are an integral part of these statements.Statements.

 11 
Table of Contents

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 three months ended March 31, 20182019 are not necessarily indicative of results that may be expected for the year ending December 31, 2018.2019. 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, including modifications to the presentation of the components of net periodic benefit costs for defined benefit pension and other postretirement plans in the income statements as discussed in Note 1(d), restricted cash and cash receipts on sold receivables in the cash flows statements as discussed in Note 1(d), and segment reporting as discussed in Note 141(c).

Discontinued operations reported in Alliant Energy’s income statements is related to various warranty claims associated with the sale of RMT, Inc. in 2013, which have resulted in operating expenses and income subsequent to the sale.

NOTE 1(b) Cash, Cash Equivalents and Restricted CashLeases - At March 31, 2018The determination of whether an arrangement qualifies as a lease occurs at the inception of the arrangement. Arrangements that qualify as leases are classified as either operating or finance. Operating and December 31, 2017, restricted cash primarily relatedfinance lease liabilities represent obligations to depositsmake payments arising from the lease. Operating and finance lease assets represent the right to use an underlying asset for the lease term and are recognized at the lease commencement date based on the present value of the lease payments over the lease term. Leases with trusteesinitial terms less than 12 months are not recognized as leases. For operating leases, an incremental borrowing rate, as determined at the lease commencement date, is used to determine the present value of the lease payments. For finance leases, the rate implicit in the lease is used to determine the present value of the lease payments. Lease terms include options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Operating lease expense is recognized on a straight-line basis over the expected lease term. Finance lease expense is comprised of depreciation and borrowing requirements in Sheboygan Power, LLC’s debt agreement. Refer to Note 1(d) for discussioninterest expenses. Finance lease assets are depreciated on a straight-line basis over the shorter of revisions to the cash flows statements to include immaterial restricted cash amounts.useful life of the underlying asset or the lease term.

NOTE 1(c) Revenue Recognition -
Utility - Revenues from Alliant Energy’s utility business are primarily from retail and wholesale electric and gas sales to customers. Utility revenues are recognized over time as services are rendered or commodities are delivered to customers, and include billed and unbilled components. The billed component is based on the reading of customers’ meters, which occurs on a systematic basis throughout each reporting period and represents the fair value of the services provided or commodities delivered. The unbilled component is estimated and recorded at the end of each reporting period based on estimated amounts of energy delivered to customers since the date of each customer’s last meter reading. The unbilled revenue is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates.

IPL and WPL accrue revenues from their wholesale customers to the extent that the actual net revenue requirements calculated in accordance with FERC-approved formula rates for the reporting period are higher or lower than the amounts billed to wholesale customers during such period. Regulatory assets or regulatory liabilities are recorded as the offset for these accrued revenues under formulaic rate-making programs. As of March 31, 2018, the related amounts accrued for IPL and WPL were not material.

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

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

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


12
Table of Contents

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

NOTE 1(d) New Accounting Standards -
Revenue Recognition - In May 2014, the Financial Accounting Standards Board issued an accounting standard providing principles for recognizing revenue for the transfer of promised goods or services to customers with the consideration to which the entity expects to be entitled in exchange for those goods or services. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018 using the modified retrospective method of adoption, which was applied to contracts with customers that were completed subsequent to January 1, 2018. Alliant Energy, IPL and WPL utilized a portfolio approach upon adoption, which involved evaluating portfolios of contracts with similar characteristics, where the effects of applying the standard were not expected to be materially different than evaluating on an individual contract basis. Upon adoption, there were no cumulative effect adjustments made to the January 1, 2018 retained earnings balances. In addition, prior period amounts have not been restated to reflect the adoption of this standard and continue to be reported under the accounting standards in effect for those periods. Alliant Energy, IPL and WPL did not have a material change in revenue recognition, including the timing and pattern of revenue recognition, as a result of the adoption of this standard. Refer to Notes 1(c) and 8 for further discussion of revenue recognition.

Leases - In February 2016, the Financial Accounting Standards Board issued an accounting standard requiring lease assets and lease liabilities, including operating leases, to be recognized on the balance sheetsheet. The accounting for allcapital leases, now referred to as finance leases, remains unchanged with terms longer than 12 months. The standard also requires disclosure of key information about leasing arrangements. Alliant Energy, IPL and WPL currently expect to adopt this standard on January 1, 2019 and are evaluating the impactadoption of this standard on their financial condition and results of operations and expect an increase in assets and liabilities from recognizing operating leases on their balance sheets.

Presentation of Net Periodic Pension and Postretirement Benefit Costs - In March 2017, the Financial Accounting Standards Board issued an accounting standard amending the income statement presentation of the components of net periodic benefit costs for defined benefit pension and other postretirement plans. The standard requires entities to (1) disaggregate the current service cost component from the other components of net periodic benefit costs and present it with other employee compensation costs in the income statement; and (2) include the other components in the income statement outside of operating income. Only the service cost component of net periodic benefit costs is eligible for capitalization into property, plant and equipment; however, IPL and WPL, as rate-regulated entities, capitalize the other components of net periodic benefit costs into regulatory assets or regulatory liabilities.standard. Alliant Energy, IPL and WPL adopted this standard on January 1, 20182019 using an optional transition approach and usedthere was no cumulative effect adjustment to the retrospective methodbalance sheets as of January 1, 2019. Prior period amounts have not been restated to reflect the adoption of this standard and continue to be reported under the accounting standards in effect for those periods. Upon transition to the presentation requirements and prospective method of adoption for the capitalization requirements.new standard, Alliant Energy, IPL and WPL usedelected the actual net periodic benefit costs adjustedland easement transition practical expedient, for approximately 40%which existing land easements that were not previously accounted for as leases under the original accounting standards did not need to be evaluated under the new accounting standard. In addition, Alliant Energy, IPL and WPL evaluated land easements that were previously accounted for as leases and determined that the majority of net periodic benefit costs allocatedthese land easements relate to capital projectsjoint-use land sites, and do not meet the criteria for leases under the retrospective methodnew accounting standard. Therefore, these land easement arrangements are no longer reflected as operating leases effective January 1, 2019. Refer to Note 7 for further discussion of adoption for the presentation requirements. The change in presentation resulted in a decrease in “Other operation and maintenance” expenses and an increase in “Other (income) and deductions” in the income statements of $4.3 million, $1.7 million and $2.6 million, respectively, for the three months ended March 31, 2017.leases.

Cash Flows Statements - In August 2016, the Financial Accounting Standards Board issuedOn January 1, 2018, Alliant Energy and IPL adopted an accounting standard providing specific guidance on several cash flow classification matters. The accounting standardthat requires classification of the consideration received for the beneficial interest obtained for transferring accounts receivable from IPL’s sales of accounts receivable program as an investing activity, instead of an operating activity. Alliant Energy and IPL currently use a method of presentation that allocates cash flows between operating and WPL adopted this standardinvesting activities based on January 1, 2018, which was applied retrospectively.daily transactional activity. For the three months ended March 31, 2017,2018, Alliant Energy and IPL reclassified $214.7 millioninitially utilized a method of the relatedpresentation that allocated cash received from IPL’s salesflows between operating and investing activities based on monthly transactional activity. The change in method of accounts receivable program from operating activitiespresentation to investing activities. The related impact ondaily transactional activity increases Alliant Energy’s and IPL’soperating cash flows statementsby $67.0 million to $156.3 million and increases IPL’s operating cash flows by $67.0 million to $1.8 million for the yearthree months ended DecemberMarch 31, 2017 was $681.9 million.2018.

In November 2016, the Financial Accounting Standards Board issued an accounting standard requiring restricted cash to be included within beginning-of-period and end-of-period cash and cash equivalents in the cash flows statements. Alliant Energy, IPL and WPL adopted this standard on January 1, 2018, which was applied retrospectively. Refer to Note 1(b) for further discussion of restricted cash.


 1312 
Table of Contents


NOTE 2. REGULATORY MATTERS
Regulatory Assets and Regulatory Liabilities -
Regulatory assets were comprised of the following items (in millions):
Alliant Energy IPL WPLAlliant Energy IPL WPL
March 31,
2018		 December 31,
2017		 March 31,
2018		 December 31,
2017		 March 31,
2018		 December 31,
2017		March 31,
2019		 December 31,
2018		 March 31,
2019		 December 31,
2018		 March 31,
2019		 December 31,
2018
Tax-related
$795.1
 
$778.2
 
$762.8
 
$750.5
 
$32.3
 
$27.7

$802.9
 
$820.6
 
$770.2
 
$783.1
 
$32.7
 
$37.5
Pension and OPEB costs538.6
 548.0
 270.0
 274.4
 268.6
 273.6
532.6
 542.3
 269.3
 274.0
 263.3
 268.3
Asset retirement obligations104.3
 109.3
 67.9
 72.5
 36.4
 36.8
112.1
 110.8
 77.5
 76.3
 34.6
 34.5
EGUs retired early60.1
 63.8
 30.4
 31.6
 29.7
 32.2
107.3
 111.6
 53.6
 55.4
 53.7
 56.2
IPL’s DAEC PPA amendment106.5
 —
 106.5
 —
 —
 —
Emission allowances23.0
 23.6
 23.0
 23.6
 —
 —
Derivatives47.6
 45.3
 25.5
 21.8
 22.1
 23.5
16.9
 28.0
 8.0
 15.1
 8.9
 12.9
Emission allowances25.4
 25.5
 25.4
 25.5
 —
 —
Other93.0
 96.6
 48.9
 55.3
 44.1
 41.3
91.1
 100.4
 43.3
 51.5
 47.8
 48.9

$1,664.1
 
$1,666.7
 
$1,230.9
 
$1,231.6
 
$433.2
 
$435.1

$1,792.4
 
$1,737.3
 
$1,351.4
 
$1,279.0
 
$441.0
 
$458.3

Regulatory liabilities were comprised of the following items (in millions):
Alliant Energy IPL WPLAlliant Energy IPL WPL
March 31,
2018		 December 31,
2017		 March 31,
2018		 December 31,
2017		 March 31,
2018		 December 31,
2017		March 31,
2019		 December 31,
2018		 March 31,
2019		 December 31,
2018		 March 31,
2019		 December 31,
2018
Tax-related
$901.3
 
$899.4
 
$399.5
 
$399.5
 
$501.8
 
$499.9

$858.1
 
$890.6
 
$366.2
 
$390.1
 
$491.9
 
$500.5
Cost of removal obligations415.6
 410.0
 274.7
 274.5
 140.9
 135.5
402.7
 401.2
 273.4
 273.3
 129.3
 127.9
Electric transmission cost recovery95.3
 90.4
 33.5
 26.4
 61.8
 64.0
104.8
 104.0
 53.0
 47.7
 51.8
 56.3
Commodity cost recovery31.2
 21.0
 24.2
 14.6
 7.0
 6.4
43.2
 16.8
 32.2
 11.9
 11.0
 4.9
IPL’s tax benefit riders25.0
 25.0
 25.0
 25.0
 —
 —
WPL’s earnings sharing mechanism25.0
 25.4
 —
 —
 25.0
 25.4
Other69.5
 51.4
 20.4
 15.4
 49.1
 36.0
48.6
 55.2
 24.0
 31.9
 24.6
 23.3

$1,537.9
 
$1,497.2
 
$777.3
 
$755.4
 
$760.6
 
$741.8

$1,482.4
 
$1,493.2
 
$748.8
 
$754.9
 
$733.6
 
$738.3

Tax-related- IPL’s DAEC PPA Amendment - In January 2019, IPL incurred an obligation to make a September 2020 buyout payment of $110 million in exchange for shortening the term of IPL’s DAEC nuclear generation PPA by five years. The IUB approved recovery of the buyout payment from IPL’s retail customers over a five-year period following the payment. The offsetting obligation has been discounted and is recorded in “Other liabilities” on Alliant Energy’s and IPL’s tax-related regulatory assets are generally impacted by certain property-related differences at IPL for which deferred tax is not recorded in the income statement pursuant to Iowa rate-making principles. Deferred tax amounts for such property-related differences at IPL are recorded to regulatory assets, along with the necessary revenue requirement tax gross-ups. During the three months ended March 31, 2018, Alliant Energy’s and IPL’s tax-related regulatory assets increased primarily due to property-related differences for qualifying repair expenditures.balance sheets.

Utility Rate Reviews
OtherIPL’s Retail Electric Rate Review (2020 Forward Test Period) - In January 2018,March 2019, IPL filed a request with the IUB issued an order requiringto increase annual electric base rates for its Iowa retail electric customers by $204 million, based on a 2020 forward-looking Test Period. IPL currently expects the proposed retail electric base rate increase to be largely offset by cost reductions in non-base rate factors, including lower electric transmission, fuel-related and other investor-owned utilities in Iowa to track all calculated differences since January 1,energy efficiency costs. IPL concurrently filed for interim retail electric rates based on 2018 resulting from Tax Reform, such that any over-collections can be refunded to its customers at a future date, if appropriate. In January 2018, the PSCW issued an order directing WPLhistorical data as adjusted for certain known and other investor-owned utilities in Wisconsin to defer the revenue requirement impacts resulting from Tax Reform since its inception. As a result of these orders, as of March 31, 2018, Alliant Energy, IPL and WPL deferred $19 million, $8 million and $11 million, respectively, related to Tax Reform, which is included in “Other”measurable changes occurring in the first quarter of 2019. An interim retail electric rate base increase of $90 million, on an annual basis, was implemented effective April 1, 2019. Implementing interim rates does not require regulatory liabilities table above.approval; however, interim rates are subject to refund pending the IUB’s final rate review decision. Interveners have challenged, among other issues, the return on common equity percentage used in interim rates, and IPL expects that the IUB will address this issue in its final decision. The IUB generally must decide on requests for retail rate changes within 10 months of the date of the application for which changes are filed. IPL currently expects a final decision from the IUB in the fourth quarter of 2019 on the interim rate increase, as well as the remaining $114 million of final rates, which would be effective in the first quarter of 2020. The key drivers for IPL’s request included recovery of capital projects, including new wind generation.

Utility Rate Reviews -
IPL’s Retail Gas Rate Review (2017(2020 Forward Test Year)Period) - In May 2018,March 2019, IPL filed a request with the IUB to increase annual gas base rates for its Iowa retail gas customers by $20$21 million, or approximately 8%. The request was based on a 2017 historical2020 forward-looking Test Year as adjusted for certain knownPeriod. IPL currently expects the proposed retail gas base rate increase will be more than offset by cost reductions in non-base rate factors, including lower cost of gas sold and measurable changes occurring up to 12 months after the commencement of the proceeding.energy efficiency costs. The key drivers for the filingIPL’s request included recovery of capital projects, partially offset by the benefits of Tax Reform. An interim retail gas rate increase of $11 million, or approximately 5%, on an annual basis, will be implemented effective May 14, 2018. The interim rate increase does not require regulatory approval; however, it will be subject to refund pending determination of final rates.projects. IPL currently expects a decision from the IUB in the fourth quarter of 2019 with final rates effective byin the secondfirst quarter of 2019. The IUB must issue a decision on requests for retail rate changes within 10 months of the date of the application for which changes are filed.2020.

IPL’s Retail Electric Rate Review (2016 Test Year) - In April 2017, IPL filed a request with the IUB to increase annual electric base rates for its Iowa retail electric customers. An interim retail electric base rate increase of $102 million, or approximately 7%, on an annual basis, was implemented effective April 13, 2017. In September 2017, IPL reached a partial, non-unanimous settlement agreement with the Iowa Office of Consumer Advocate, the Iowa Business Energy Coalition and the Large Energy Group for an annual electric base rate increase of $130 million, or approximately 9%. In February 2018, the IUB issued an order approving the settlement. Final rates were effective May 1, 2018. For the three months ended

 1413 
Table of Contents

March 31, 2018, Alliant Energy and IPL recorded increases in electric base rates of $23 million in conjunction with the interim retail electric base rate increase.

NOTE 3. PROPERTY, PLANT AND EQUIPMENT
Utility -
Natural Gas-Fired Generation Project -
WPL’s West Riverside Energy Center - WPL is currently constructing West Riverside, an approximate 730 MW natural gas-fired combined-cycle EGU. Construction began in 2016 and is currently expected to be completed by early 2020. As of March 31, 2018, Alliant Energy and WPL recorded capitalized expenditures for construction work in progress of $347 million and AFUDC of $20 million for West Riverside in “Property, plant and equipment, net” on their balance sheets. These capital expenditures reflect WPL’s portion of West Riverside. Certain WPL electric cooperatives acquired approximately 60 MW of West Riverside in January 2018, and will fund their share of capital expenditures during construction. As part of the electric cooperatives’ acquisitions, the current wholesale power supply agreements with the various electric cooperatives were extended by at least four years until 2026 with automatic continuation of such agreements unless terminated by either party, with a five-year notice requirement.

Wind Generation -
IPL’s Expansion of Wind Generation - IPL currently plans to add up to 1,000 MW of new wind generation to its existing generation portfolio. These wind projects are expected to be placed into service in 2019 and 2020. As of March 31, 2018, Alliant Energy and IPL recorded capitalized expenditures for construction work in progress of $385 million and AFUDC of $16 million for this expansion of wind generation in “Property, plant and equipment, net” on their balance sheets.

WPL’s Acquisition of Forward Wind Energy Center (FWEC) - In January 2018 and March 2018, WPL received approval from FERC and the PSCW, respectively, to acquire the assets of FWEC, which is a 129 MW wind farm located in Wisconsin. In April 2018, WPL acquired 55 MW of FWEC for approximately $74 million.

NOTE 4. RECEIVABLES
Sales of Accounts Receivable - IPL maintains a Receivables Purchase and Sale Agreement (Receivables Agreement) whereby it may sell its customer accounts receivables, unbilled revenues and certain other accounts receivables to a third party through wholly-owned and consolidated special purpose entities. In March 2018, IPL amended and extended through March 2021 the purchase commitment from the third party to which it sells its receivables. Effective April 2018, the limit on cash proceeds will fluctuate between $90 million and $110 million. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. As of March 31, 20182019, IPL had no$21.0 million of available capacity under its sales of accounts receivable program. For the three months ended March 31, 2018 and 2017, IPL’s costs incurred related to the sales of accounts receivable program were not material.

IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three months ended March 31 were as follows (in millions):
2018 20172019 2018
Maximum outstanding aggregate cash proceeds
$116.0
 
$79.0

$108.0
 
$116.0
Average outstanding aggregate cash proceeds61.1
 38.4
81.0
 61.1

The attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):
 March 31, 2018 December 31, 2017
Customer accounts receivable
$156.1
 
$133.8
Unbilled utility revenues93.2
 112.7
Other receivables0.3
 0.3
Receivables sold to third party249.6
 246.8
Less: cash proceeds116.0
 12.0
Deferred proceeds133.6
 234.8
Less: allowance for doubtful accounts12.7
 12.7
Fair value of deferred proceeds
$120.9
 
$222.1


15
Table of Contents
 March 31, 2019 December 31, 2018
Customer accounts receivable
$169.9
 
$140.1
Unbilled utility revenues86.8
 97.1
Other receivables0.1
 0.1
Receivables sold to third party256.8
 237.3
Less: cash proceeds69.0
 108.0
Deferred proceeds187.8
 129.3
Less: allowance for doubtful accounts9.5
 9.9
Fair value of deferred proceeds
$178.3
 
$119.4

As of March 31, 2018,2019, outstanding receivables past due under the Receivables Agreement were $50.7$38.8 million. Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three months ended March 31 were as follows (in millions):
2018 20172019 2018
Collections
$517.0
 
$501.2

$555.8
 
$517.0
Write-offs, net of recoveries6.1
 4.6
5.5
 6.1

NOTE 5.4. INVESTMENTS AND ACQUISITIONS
Unconsolidated Equity Investments - Alliant Energy’s equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three months ended March 31 was as follows (in millions):
2018 20172019 2018
ATC Holdings
($8.7) 
($11.5)
($9.5) 
($8.7)
Non-utility wind farm in Oklahoma(12.1) —
(1.1) (12.1)
Other(0.5) —
(0.3) (0.5)

($21.3) 
($11.5)
($10.9) 
($21.3)

Non-utility Wind Farm in OklahomaTransportation Acquisitions - Alliant Energy’s interest in a non-utility wind farm in Oklahoma commenced in July 2017. As a result, there was no corresponding equity income recognized inIn the first quarter of 2017. The equity income recognized2019, Alliant Energy, through its wholly-owned non-utility subsidiaries, completed acquisitions of freight management companies located in the first quarterCedar Rapids, Iowa and Stoughton, Wisconsin. These acquisitions were purchased for $21 million, including contingent consideration of 2018 was primarily related to the impacts of Tax Reform. The liquidation method utilized to recognize Alliant Energy’s share of the wind farm’s earnings includes utilizing the federal income tax rate in effect as of the end of the measurement period. The lower federal income tax rate effective as of January 1, 2018 resulted in an acceleration of earnings attributable to Alliant Energy’s interest in the Oklahoma wind farm. This increase in earnings$8 million, which is expected to reverse over time.be paid within two years. The purchase price was largely allocated to intangibles and the remainder was allocated to working capital and property.

NOTE 6.5. COMMON EQUITY
Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows:
Shares outstanding, January 1, 20182019231,348,646236,063,279
Equity forward agreements1,090,300
Shareowner Direct Plan issuances166,527142,090
Equity-based compensation plans (Note 10(b))
5,078101,478
Other(38,4232,738)
Shares outstanding, March 31, 20182019231,481,828237,394,409


14
Table of Contents

Dividend RestrictionsEquity Forward Agreements - In December 2018, Alliant Energy entered into forward sale agreements with various counterparties in connection with a public offering of 8,358,973 shares of Alliant Energy common stock. The initial forward sale price of $44.33 per share is subject to daily adjustment based on a floating interest rate factor, and will decrease by other fixed amounts specified in the forward sale agreements. In the first quarter of 2019, Alliant Energy settled $48 million under the forward sale agreements by delivering 1,090,300 shares of newly issued Alliant Energy common stock at a forward sale price of $44.13 per share. Alliant Energy used the net proceeds from the settlement for general corporate purposes. As of March 31, 2019, 96,261 shares were included in the calculation of diluted EPS related to the remaining securities under the forward sale agreements.

Changes in Shareowners’ Equity - AsA summary of March 31, 2018, IPL’s amount of retained earnings that were free of dividend restrictionschanges in shareowners’ equity was as follows (in millions):$683 million. As of March 31, 2018, WPL’s amount of retained earnings that were free of dividend restrictions was $105 million for the remainder of 2018.
Alliant EnergyTotal 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 March 31, 2019             
Beginning balance, January 1
$2.4
 
$2,045.5
 
$2,545.9
 
$1.7
 
($9.8) 
$200.0
 
$4,785.7
Net income attributable to Alliant Energy common shareowners    125.1
       125.1
Common stock dividends ($0.355 per share)    (83.7)       (83.7)
Equity forward settlements and Shareowner Direct Plan issuances

 54.6
         54.6
Equity-based compensation plans and other  (0.1)     0.1
   —
Other comprehensive income, net of tax      0.7
     0.7
Ending balance, March 31
$2.4
 
$2,100.0
 
$2,587.3
 
$2.4
 
($9.7) 
$200.0
 
$4,882.4
Three Months Ended March 31, 2018             
Beginning balance, January 1
$2.3
 
$1,845.5
 
$2,346.0
 
($0.5) 
($11.1) 
$200.0
 
$4,382.2
Net income attributable to Alliant Energy common shareowners    120.9
       120.9
Common stock dividends ($0.335 per share)    (77.5)       (77.5)
Shareowner Direct Plan issuances  6.3
         6.3
Equity-based compensation plans  (0.4)         (0.4)
Ending balance, March 31
$2.3
 
$1,851.4
 
$2,389.4
 
($0.5) 
($11.1) 
$200.0
 
$4,431.5
IPLTotal IPL Common Equity    
   Additional   Cumulative  
 Common Paid-In Retained Preferred Total
 Stock Capital Earnings Stock Equity
Three Months Ended March 31, 2019         
Beginning balance, January 1
$33.4
 
$2,222.8
 
$774.5
 
$200.0
 
$3,230.7
Earnings available for common stock    53.3
   53.3
Common stock dividends    (42.0)   (42.0)
Capital contribution from parent  100.0
     100.0
Ending balance, March 31
$33.4
 
$2,322.8
 
$785.8
 
$200.0
 
$3,342.0
Three Months Ended March 31, 2018         
Beginning balance, January 1
$33.4
 
$1,797.8
 
$678.5
 
$200.0
 
$2,709.7
Earnings available for common stock    46.7
   46.7
Common stock dividends    (41.9)   (41.9)
Ending balance, March 31
$33.4
 
$1,797.8
 
$683.3
 
$200.0
 
$2,714.5

Restricted Net Assets
15
Table of Subsidiaries - As of March 31, 2018, the amount of IPL’s and WPL’s net assets that were not available to be transferred to their parent company, Alliant Energy, in the form of loans, advances or cash dividends without the consent of IPL’s and WPL’s regulatory authorities was $1.8 billion and $1.8 billion, respectively.Contents

WPL  Additional   Total
 Common Paid-In Retained Common
 Stock Capital Earnings Equity
Three Months Ended March 31, 2019       
Beginning balance, January 1
$66.2
 
$1,309.0
 
$774.3
 
$2,149.5
Earnings available for common stock    65.7
 65.7
Common stock dividends    (36.0) (36.0)
Ending balance, March 31
$66.2
 
$1,309.0
 
$804.0
 
$2,179.2
Three Months Ended March 31, 2018       
Beginning balance, January 1
$66.2
 
$1,109.0
 
$706.3
 
$1,881.5
Earnings available for common stock    54.0
 54.0
Common stock dividends    (35.0) (35.0)
Ending balance, March 31
$66.2
 
$1,109.0
 
$725.3
 
$1,900.5

Comprehensive Income - For the three months ended March 31, 20182019 and 20172018, Alliant Energy had noEnergy’s other comprehensive income;income was not material; therefore, its comprehensive income was substantially equal to its net income and its comprehensive income attributable to Alliant Energy common shareowners was substantially equal to its net income attributable to Alliant Energy common shareowners for such periods. For the three months ended March 31, 20182019 and 2017,2018, IPL and WPL had no other comprehensive income; therefore, their comprehensive income was equal to their net income and their comprehensive income available for common stock was equal to their earnings available for common stock for such periods.

NOTE 7.6. DEBT
Note 7(a)NOTE 6(a) Short-term Debt - In March 2019, Alliant Energy, IPL and WPL extended their single credit facility agreement by one year, which currently expires in August 2023. As of March 31, 2019, the short-term borrowing capacity under the agreement totaled $1 billion ($450 million for Alliant Energy at the parent company, $250 million for IPL and $300 million for WPL). Information regarding commercial paper classified as short-term debt was as follows (dollars in millions):
March 31, 2018Alliant Energy IPL WPL
Commercial paper outstanding$336.4 $— $30.6
Commercial paper weighted average interest rates2.3% N/A 1.8%
Available credit facility capacity (a)$617.7 $204.1 $319.4

16
Table of Contents

March 31, 2019Alliant Energy IPL WPL
Commercial paper outstanding$514.7 $— $138.4
Commercial paper weighted average interest rates2.6% N/A 2.5%
Available credit facility capacity (a)$370.3 $135.0 $161.6
Alliant Energy IPL WPLAlliant Energy IPL WPL
Three Months Ended March 312018 2017 2018 2017 2018 20172019 2018 2019 2018 2019 2018
Maximum amount outstanding (based on daily outstanding balances)$336.4 $325.5 $3.0 $9.2 $36.7 $113.6$600.6 $336.4 $50.4 $3.0 $195.1 $36.7
Average amount outstanding (based on daily outstanding balances)$310.1 $276.5 $— $0.1 $11.5 $79.1$498.8 $310.1 $0.6 $— $138.1 $11.5
Weighted average interest rates1.9% 0.9% 1.8% 1.1% 1.6% 0.7%2.7% 1.9% 2.8% 1.8% 2.5% 1.6%

(a)Alliant Energy’s and IPL’s available credit facility capacities reflect outstanding commercial paper classified as both short- and long-term debt at March 31, 2018.2019.

NOTE 7(b)6(b) Long-term Debt - As of March 31, 2018, $45.92019, $115.0 million of commercial paper was recorded in “Long-term debt, net” on Alliant Energy’s and IPL’s balance sheets due to the existence of a long-term credit facility that back-stops this commercial paper balance, along with Alliant Energy’s and IPL’s intent and ability to refinance these balances on a long-term basis. As of March 31, 2018,2019, this commercial paper balance had a 2.3%2.7% interest rate.

In April 2018, AEF entered into a2019, IPL issued $300 million variable-rate (2.3% at April 30, 2018) term loan credit agreement (with Alliant Energyof 3.6% senior debentures due 2029. The senior debentures were issued as guarantor)green bonds, and usedall of the net proceeds from borrowings under this agreementwere allocated for general corporate purposes. AEF’s term loan credit agreement expires in April 2020the construction and includes substantially the same financial covenants that are included in Alliant Energy’s credit facility agreement.development of IPL’s wind projects.

NOTE 8. REVENUES7. LEASES
Revenues from Operating Leases - Alliant Energy’s, IPL’s and WPL’s utility businessesoperating leases primarily include leases of space on telecommunication towers and leases of property. Operating lease details are primarilyas follows (dollars in millions):

16
Table of Contents

 Alliant Energy IPL WPL
March 31, 2019     
Property, plant and equipment, net
$18
 
$10
 
$7
Other current liabilities
$3
 
$1
 
$1
Other liabilities15
 9
 6
Total operating lease liabilities
$18
 
$10
 
$7
Three Months Ended March 31, 2019     
Operating lease cost
$1
 
$—
 
$—
Weighted average remaining lease term12 years
 13 years
 10 years
Weighted average discount rate4% 4% 4%

Finance Lease - WPL’s finance lease is an agreement for WPL to lease the Sheboygan Falls Energy Facility from retail and wholesale electric and gas sales provided to customers based on approved tariffs or specific contracts with customers. IPL’s and WPL’s primary performance obligations under such arrangements are to deliver electricity and gas, and their customers simultaneously receive and consumeAEF’s Non-utility Generation business through 2025, the electricity and gas. For such arrangements, revenues are recognized equivalent toinitial lease term. WPL is responsible for the valueoperation of the electricity or gas supplied during each period, including amounts billed during each periodEGU and changeshas exclusive rights to its output. This finance lease contains two lease renewal periods, which are not included in amounts estimatedthe finance lease obligation, as well as an option to be billedpurchase the facility at the end of each period. IPL and WPL apply the right to invoice method to measure progress towards completing performance obligations to transfer electricity and gas to their customers.

IPL provides retail electric and gas service to customers in Iowa, and WPL providesinitial lease term. WPL’s retail and wholesale electric and retail gas service to customersrates include recovery of the Sheboygan Falls Energy Facility lease payments. WPL’s finance lease details are as follows (dollars in Wisconsin. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa, as well as steam from its Prairie Creek Generating Station to high-pressure steam customers in Iowa.millions):
March 31, 2019
Property, plant and equipment, net
$37
Other current liabilities
$8
Finance lease obligations - Sheboygan Falls Energy Facility58
Total finance lease liabilities
$66
Three Months Ended March 31, 2019
Depreciation expense
$1
Interest expense2
Total finance lease expense
$3
Remaining lease term6 years
Discount rate11%

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

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

Revenues from Alliant Energy’s non-utility business customers are primarily from its Transportation business, which includes a short-line railway that provides freight service between Cedar Rapids, Iowa and Iowa City, Iowa; a barge terminal and hauling services on the Mississippi River; and other transfer and storage services.

Expected Maturities - As of March 31, 2018, revenue2019, expected maturities of lease liabilities were as follows (in millions):
 Remainder of 2019 2020 2021 2022 2023 Thereafter Total Less: amount representing interest Present value of minimum lease payments
Operating Leases:                 
Alliant Energy
$2
 
$2
 
$2
 
$2
 
$2
 
$13
 
$23
 
$5
 
$18
IPL1
 1
 1
 1
 1
 9
 14
 4
 10
WPL1
 1
 1
 1
 1
 3
 8
 1
 7
WPL’s Finance Lease:                 
Sheboygan Falls Energy Facility11
 15
 15
 15
 15
 20
 91
 25
 66

Prior period amounts have not been restated to reflect the adoption of the new lease accounting standard and continue to be recognizedreported under the accounting standards in anyeffect for those periods. As of December 31, 2018, future year related to remaining performance obligations is not material,minimum operating (excluding contingent rentals) and capital lease payments were as the majority of revenues are recognized as services are rendered or commodities are delivered, and are from contracts with durations of less than one year. Alliant Energy, IPL and WPL do not have any material contract assets or contract liabilities, or contract acquisition fulfillment costs.follows (in millions):
 2019 2020 2021 2022 2023 Thereafter Total Less: amount representing interest Present value of minimum capital lease payments
Operating Leases:                 
Alliant Energy
$5
 
$5
 
$3
 
$3
 
$2
 
$12
 
$30
    
IPL3
 2
 2
 2
 2
 12
 23
    
WPL2
 3
 1
 —
 —
 —
 6
    
WPL’s Capital Lease:                 
Sheboygan Falls Energy Facility
$15
 
$15
 
$15
 
$15
 
$15
 
$19
 
$94
 
$26
 
$68


 17 
Table of Contents

NOTE 8. REVENUES
Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):
Alliant Energy IPL WPLAlliant Energy IPL WPL
Three Months Ended March 312018 2017 2018 2017 2018 20172019 2018 2019 2018 2019 2018
Electric Utility:                      
Retail - residential
$259.4
 
$241.2
 
$142.2
 
$123.3
 
$117.2
 
$117.9

$274.7
 
$259.4
 
$147.5
 
$142.2
 
$127.2
 
$117.2
Retail - commercial174.0
 165.7
 111.6
 99.5
 62.4
 66.2
181.1
 174.0
 116.6
 111.6
 64.5
 62.4
Retail - industrial201.9
 195.0
 114.8
 103.9
 87.1
 91.1
208.7
 201.9
 116.1
 114.8
 92.6
 87.1
Wholesale53.8
 63.4
 24.3
 21.3
 29.5
 42.1
46.5
 53.8
 16.9
 24.3
 29.6
 29.5
Bulk power and other19.6
 12.3
 12.8
 8.2
 6.8
 4.1
32.4
 19.6
 22.7
 12.8
 9.7
 6.8
Total Electric Utility708.7
 677.6
 405.7
 356.2
 303.0
 321.4
743.4
 708.7
 419.8
 405.7
 323.6
 303.0
Gas Utility:                      
Retail - residential110.6
 89.9
 65.5
 47.9
 45.1
 42.0
131.8
 110.6
 77.9
 65.5
 53.9
 45.1
Retail - commercial57.0
 49.8
 31.6
 25.8
 25.4
 24.0
63.6
 57.0
 34.8
 31.6
 28.8
 25.4
Retail - industrial5.8
 4.8
 2.7
 2.8
 3.1
 2.0
5.4
 5.8
 3.2
 2.7
 2.2
 3.1
Transportation/other12.2
 9.8
 8.3
 6.6
 3.9
 3.2
15.0
 12.2
 8.7
 8.3
 6.3
 3.9
Total Gas Utility185.6
 154.3
 108.1
 83.1
 77.5
 71.2
215.8
 185.6
 124.6
 108.1
 91.2
 77.5
Other Utility:                      
Steam9.4
 8.6
 9.4
 8.6
 —
 —
8.4
 9.4
 8.4
 9.4
 —
 —
Other utility3.8
 3.1
 2.6
 2.6
 1.2
 0.5
2.7
 3.8
 2.3
 2.6
 0.4
 1.2
Total Other Utility13.2
 11.7
 12.0
 11.2
 1.2
 0.5
11.1
 13.2
 10.7
 12.0
 0.4
 1.2
Non-Utility and Other:                      
Transportation and other8.8
 10.3
 —
 —
 —
 —
16.9
 8.8
 —
 —
 —
 —
Total Non-Utility and Other8.8
 10.3
 —
 —
 —
 —
16.9
 8.8
 —
 —
 —
 —
Total revenues
$916.3
 
$853.9
 
$525.8
 
$450.5
 
$381.7
 
$393.1

$987.2
 
$916.3
 
$555.1
 
$525.8
 
$415.2
 
$381.7

NOTE 9. INCOME TAXES
Income Tax Rates - The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit)taxes by income from continuing operations before income taxes.
Alliant Energy IPL WPLAlliant Energy IPL WPL
Three Months Ended March 312018 2017 2018 2017 2018 20172019 2018 2019 2018 2019 2018
Statutory federal income tax rate21.0 % 35.0 % 21.0% 35.0% 21.0 % 35.0 %21.0 % 21.0 % 21.0% 21.0% 21.0 % 21.0 %
State income taxes, net of federal benefits7.5
 5.4
 8.5
 6.3
 6.2
 5.1
6.7
 7.5
 7.2
 8.5
 6.2
 6.2
Production tax credits(9.2) (5.5) (14.0) (5.4) (4.9) (6.7)
Effect of rate-making on property-related differences(7.4) (7.5) (13.5) (17.9) (2.4) (1.7)(5.6) (7.4) (9.2) (13.5) (2.3) (2.4)
Production tax credits(5.5) (5.9) (5.4) (6.6) (6.7) (7.0)
Amortization of excess deferred taxes(0.9) (0.4) (0.2) —
 (1.4) (0.1)
IPL’s tax benefit riders(2.2) (7.8) (4.7) (19.4) —
 —
(0.7) (2.2) (1.5) (4.7) —
 —
Other items, net(1.4) (4.4) —
 (7.6) (0.3) (0.4)(0.7) (1.0) 0.3
 —
 (0.4) (0.2)
Overall income tax rate12.0% 14.8% 5.9% (10.2%) 17.8% 31.0%10.6% 12.0% 3.6% 5.9% 18.2% 17.8%

Deferred Tax Assets and Liabilities -For the three months ended March 31, 2018, Alliant Energy’s, IPL’s and WPL’s deferred tax liabilities increased $33.2 million, $15.8 million and $8.5 million, respectively. These increases were primarily due to property-related differences and the utilization of federal net operating losses during the three months ended March 31, 2018. These increases were partially offset by an increase in federal credit carryforwards recorded during the three months ended March 31, 2018.

Carryforwards - At March 31, 2018,2019, carryforwards and expiration dates were estimated as follows (in millions):
Range of Expiration Dates Alliant Energy IPL WPLRange of Expiration Dates Alliant Energy IPL WPL
Federal net operating losses2030-2037 
$774
 
$497
 
$176
2031-2039 
$776
 
$551
 
$129
State net operating losses2018-2038 707
 13
 2
2019-2039 785
 13
 2
Federal tax credits2022-2038 277
 123
 136
2022-2039 307
 138
 151


18
Table of Contents

NOTE 10. BENEFIT PLANS
NOTE 10(a) Pension and Other Postretirement BenefitsOPEB Plans -
Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three months ended March 31 are included in the tables below (in millions). The service cost component of net periodic benefit costs is included in “Other operationFor IPL and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements. In IPL’s and WPL’s tables below, the defined benefit pension planWPL, amounts represent those respective amounts for their bargaining unitcurrent and former employees covered under the qualified plans that they sponsor, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans. In IPL’s and WPL’s tables below, the OPEB plan amounts represent respective amounts for their employees, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Corporate Services sponsored OPEB plan.

18
Table of Contents

Defined Benefit Pension Plans OPEB PlansDefined Benefit Pension PlansOPEB Plans
Alliant Energy2018 2017 2018 20172019 2018 2019 2018
Service cost
$3.0
 
$3.1
 
$1.1
 
$1.2

$2.4
 
$3.0
 
$0.8
 
$1.1
Interest cost11.7
 12.8
 1.9
 2.2
12.5
 11.7
 2.1
 1.9
Expected return on plan assets(17.4) (16.4) (1.5) (1.5)(15.0) (17.4) (1.2) (1.5)
Amortization of prior service credit(0.2) (0.1) —
 (0.1)(0.2) (0.2) —
 —
Amortization of actuarial loss8.8
 9.4
 0.8
 1.0
9.1
 8.8
 0.8
 0.8

$5.9
 
$8.8
 
$2.3
 
$2.8

$8.8
 
$5.9
 
$2.5
 
$2.3
Defined Benefit Pension Plans OPEB PlansDefined Benefit Pension Plans OPEB Plans
IPL2018 2017 2018 20172019 2018 2019 2018
Service cost
$1.8
 
$1.8
 
$0.4
 
$0.5

$1.5
 
$1.8
 
$0.3
 
$0.4
Interest cost5.3
 5.9
 0.8
 0.9
5.7
 5.3
 0.8
 0.8
Expected return on plan assets(8.1) (7.7) (1.1) (1.1)(7.0) (8.1) (0.9) (1.1)
Amortization of prior service credit(0.1) —
 —
 —
Amortization of actuarial loss3.7
 4.0
 0.3
 0.5
3.9
 3.7
 0.4
 0.3

$2.7
 
$4.0
 
$0.4
 
$0.8

$4.0
 
$2.7
 
$0.6
 
$0.4
Defined Benefit Pension Plans OPEB PlansDefined Benefit Pension Plans OPEB Plans
WPL2018 2017 2018 20172019 2018 2019 2018
Service cost
$1.1
 
$1.2
 
$0.4
 
$0.5

$0.9
 
$1.1
 
$0.3
 
$0.4
Interest cost5.0
 5.5
 0.8
 0.9
5.4
 5.0
 0.8
 0.8
Expected return on plan assets(7.6) (7.1) (0.2) (0.2)(6.5) (7.6) (0.1) (0.2)
Amortization of prior service credit—
 —
 —
 (0.1)(0.1) —
 —
 —
Amortization of actuarial loss4.3
 4.6
 0.5
 0.4
4.4
 4.3
 0.4
 0.5

$2.8
 
$4.2
 
$1.5
 
$1.5

$4.1
 
$2.8
 
$1.4
 
$1.5

NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three months ended March 31 was as follows (in millions):
Alliant Energy IPL WPLAlliant Energy IPL WPL
2018 2017 2018 2017 2018 20172019 2018 2019 2018 2019 2018
Compensation expense
$3.3
 
$3.2
 
$1.8
 
$1.7
 
$1.3
 
$1.4

$4.7
 
$3.3
 
$2.6
 
$1.8
 
$1.8
 
$1.3
Income tax benefits0.9
 1.3
 0.5
 0.7
 0.4
 0.5
1.3
 0.9
 0.8
 0.5
 0.5
 0.4

As of March 31, 2018,2019, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $14.6$13.7 million, $8.1$7.6 million and $5.9$5.6 million, respectively, which is expected to be recognized over a weighted average period of between one and two years.

In the first quarter of 2019, performance shares, performance restricted stock units and restricted stock units were granted to key employees and will be paid out in shares, and are therefore accounted for as equity awards. The 2019 performance shares contain a market condition based on total shareowner return relative to an investor-owned utility peer group. The fair value of each performance share is based on the fair value of the underlying common stock on the grant date and the probability of satisfying the market condition contained in the agreement during a three-year performance period. In the first quarter of 2019, 80,837 performance shares were granted with a grant date fair value of $46.35. The 2019 performance restricted stock units will vest based on the achievement of certain targets (specified growth of consolidated net income from continuing operations) during a three-year performance period. The actual number of performance shares and performance restricted units that will be paid out upon vesting is dependent upon actual performance and may range from zero to 200% of the target number of shares or units, as applicable. The 2019 restricted stock units will vest based on the expiration of a three-year time-vesting period. In the first quarter of 2019, 80,837 performance restricted stock units and 95,938 restricted stock units were granted with a grant date fair value of $45.63, which is based on the closing market price of one share of Alliant Energy’s common stock on the grant date of the award. As of March 31, 2019, an immaterial amount of shares was included in the calculation of diluted EPS related to the nonvested equity awards.


 19 
Table of Contents

Performance Shares and Performance Units - A summary of the performance shares and performance units activity for the three months ended March 31, 2018, with amounts representing the target number of awards, was as follows:
 Performance Shares Performance Units
Nonvested awards, January 1223,511
 71,737
Granted74,163
 19,840
Vested(90,806) (31,910)
Nonvested awards, March 31206,868
 59,667

Vested Awards - During the three months ended March 31, 2018, certain performance shares and performance units that were granted in 2015 vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows:
 Performance Shares Performance Units
Performance awards vested90,806
 31,910
Percentage of target number of performance awards137.5% 137.5%
Aggregate payout value (in millions)
$5.3
 
$1.4
Payout - cash (in millions)
$4.9
 
$1.4
Payout - common stock shares issued5,078
 N/A

Fair Value of Awards - At March 29, 2018, Alliant Energy’s common stock closing price was $40.86. Additional information related to fair values of nonvested performance shares and performance units at March 31, 2018, by year of grant, was as follows:
 Performance Shares Performance Units
 2018 Grant 2017 Grant 2016 Grant 2018 Grant 2017 Grant 2016 Grant
Nonvested awards at target74,163
 65,350
 67,355
 19,840
 18,600
 21,227
Estimated payout percentage based on performance criteria100% 115% 160% 100% 115% 160%
Fair values of each nonvested award
$40.86
 
$46.99
 
$65.38
 
$40.86
 
$46.99
 
$65.38

Performance Restricted Stock Units - A summary of the performance restricted stock units activity for the three months ended March 31, 2018, with amounts representing the target number of units, was as follows:
 Units 
Weighted Average
Grant Date Fair Value
Nonvested units, January 1132,705
 
$36.50
Granted74,163
 38.60
Nonvested units, March 31206,868
 37.25

Restricted Stock Units - A summary of the restricted stock units activity for the three months ended March 31, 2018, was as follows:
Nonvested units, January 1113,749
Granted63,568
Nonvested units, March 31177,317


20
Table of Contents

NOTE 11. ASSET RETIREMENT OBLIGATIONS
A reconciliation of the changes in asset retirement obligations associated with long-lived assets for the three months ended March 31, 2019 is as follows (in millions):
 Alliant Energy IPL
Balance, January 1
$177.5
 
$118.3
Liabilities settled(0.7) (0.6)
Liabilities incurred (a)25.9
 25.9
Accretion expense1.6
 1.0
Balance, March 31
$204.3
 
$144.6

(a)During the three months ended March 31, 2019, Alliant Energy and IPL recognized additional asset retirement obligations related to IPL’s newly constructed Upland Prairie and English Farms 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. 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 EnergyMarch 31, 2018 December 31, 2017
   Fair Value   Fair Value
 Carrying Level Level Level   Carrying Level Level Level  
 Amount 1 2 3 Total Amount 1 2 3 Total
Assets:                   
Derivatives
$14.1
 
$—
 
$4.1
 
$10.0
 
$14.1
 
$25.1
 
$—
 
$4.1
 
$21.0
 
$25.1
Deferred proceeds120.9
 —
 —
 120.9
 120.9
 222.1
 —
 —
 222.1
 222.1
Liabilities and equity:                   
Derivatives46.7
 —
 7.3
 39.4
 46.7
 41.7
 —
 8.5
 33.2
 41.7
Long-term debt (incl. current maturities)4,912.5
 —
 5,366.6
 2.5
 5,369.1
 4,866.3
 —
 5,444.6
 2.9
 5,447.5
Cumulative preferred stock of IPL200.0
 198.4
 —
 —
 198.4
 200.0
 203.8
 —
 —
 203.8
IPLMarch 31, 2018 December 31, 2017
   Fair Value   Fair Value
 Carrying Level Level Level   Carrying Level Level Level  
 Amount 1 2 3 Total Amount 1 2 3 Total
Assets:                   
Derivatives
$7.9
 
$—
 
$1.7
 
$6.2
 
$7.9
 
$17.1
 
$—
 
$2.0
 
$15.1
 
$17.1
Deferred proceeds120.9
 —
 —
 120.9
 120.9
 222.1
 —
 —
 222.1
 222.1
Liabilities and equity:                   
Derivatives24.7
 —
 3.1
 21.6
 24.7
 19.4
 —
 2.9
 16.5
 19.4
Long-term debt (incl. current maturities)2,452.2
 —
 2,635.7
 —
 2,635.7
 2,406.0
 —
 2,665.7
 —
 2,665.7
Cumulative preferred stock200.0
 198.4
 —
 —
 198.4
 200.0
 203.8
 —
 —
 203.8
WPLMarch 31, 2018 December 31, 2017
   Fair Value   Fair Value
 Carrying Level Level Level   Carrying Level Level Level  
 Amount 1 2 3 Total Amount 1 2 3 Total
Assets:                   
Derivatives
$6.2
 
$—
 
$2.4
 
$3.8
 
$6.2
 
$8.0
 
$—
 
$2.1
 
$5.9
 
$8.0
Liabilities:                   
Derivatives22.0
 —
 4.2
 17.8
 22.0
 22.3
 —
 5.6
 16.7
 22.3
Long-term debt1,833.7
 —
 2,102.7
 —
 2,102.7
 1,833.4
 —
 2,147.9
 —
 2,147.9

Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions):
Alliant EnergyCommodity Contract Derivative  
 Assets and (Liabilities), net Deferred Proceeds
Three Months Ended March 312018 2017 2018 2017
Beginning balance, January 1
($12.2) 
$8.7
 
$222.1
 
$211.1
Total net losses included in changes in net assets (realized/unrealized)(9.8) (35.2) —
 —
Sales—
 (0.1) —
 —
Settlements (a)(7.4) (6.3) (101.2) (62.1)
Ending balance, March 31
($29.4) 
($32.9) 
$120.9
 
$149.0
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at March 31
($9.4) 
($33.7) 
$—
 
$—

21
Table of Contents

IPLCommodity Contract Derivative  
 Assets and (Liabilities), net Deferred Proceeds
Three Months Ended March 312018 2017 2018 2017
Beginning balance, January 1
($1.4) 
$10.1
 
$222.1
 
$211.1
Total net losses included in changes in net assets (realized/unrealized)(7.6) (12.7) —
 —
Sales—
 (0.1) —
 —
Settlements (a)(6.4) (5.6) (101.2) (62.1)
Ending balance, March 31
($15.4) 
($8.3) 
$120.9
 
$149.0
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at March 31
($7.3) 
($11.4) 
$—
 
$—
WPLCommodity Contract Derivative
 Assets and (Liabilities), net
Three Months Ended March 312018 2017
Beginning balance, January 1
($10.8) 
($1.4)
Total net losses included in changes in net assets (realized/unrealized)(2.2) (22.5)
Settlements(1.0) (0.7)
Ending balance, March 31
($14.0) 
($24.6)
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at March 31
($2.1) 
($22.3)

(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 electric, natural gas, coal and diesel fuel commodity contracts categorized as Level 3 was recognized as net derivative assets (liabilities) as follows (in millions):
 Alliant Energy IPL WPL
 Excluding FTRs FTRs Excluding FTRs FTRs Excluding FTRs FTRs
March 31, 2018
($34.6) 
$5.2
 
($20.0) 
$4.6
 
($14.6) 
$0.6
December 31, 2017(23.5) 11.3
 (11.5) 10.1
 (12.0) 1.2

NOTE 12. DERIVATIVE INSTRUMENTS
Commodity Derivatives -
Notional Amounts - As of March 31, 2018,2019, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):
Electricity FTRs Natural Gas Coal Diesel FuelFTRs Natural Gas Coal Diesel Fuel
MWhs Years MWhs Years Dths Years Tons Years Gallons YearsMWhs Years Dths Years Tons Years Gallons Years
Alliant Energy990
 2018 3,370
 2018 156,074
 2018-2026 7,144
 2018-2020 5,670
 2018-20193,903
 2019 158,337
 2019-2026 10,042
 2019-2021 2,268
 2019
IPL—
 — 2,252
 2018 65,541
 2018-2026 2,975
 2018-2020 —
 —2,378
 2019 68,345
 2019-2026 4,429
 2019-2021 —
 —
WPL990
 2018 1,118
 2018 90,533
 2018-2026 4,169
 2018-2020 5,670
 2018-20191,525
 2019 89,992
 2019-2026 5,613
 2019-2021 2,268
 2019

Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities. The fair values of current derivative assets are included in “Other current assets,” non-current derivative assets are included in “Deferred charges and other,” current derivative liabilities are included in “Other current liabilities” and non-current derivative liabilities are included in “Other liabilities” on the balance sheets as follows (in millions):
 Alliant Energy IPL WPL
 March 31,
2018		 December 31,
2017		 March 31,
2018		 December 31,
2017		 March 31,
2018		 December 31,
2017
Current derivative assets
$10.8
 
$21.1
 
$7.0
 
$15.8
 
$3.8
 
$5.3
Non-current derivative assets3.3
 4.0
 0.9
 1.3
 2.4
 2.7
Current derivative liabilities15.9
 18.7
 4.8
 5.0
 11.1
 13.7
Non-current derivative liabilities30.8
 23.0
 19.9
 14.4
 10.9
 8.6


22
Table of Contents
 Alliant Energy IPL WPL
 March 31,
2019		 December 31,
2018		 March 31,
2019		 December 31,
2018		 March 31,
2019		 December 31,
2018
Current derivative assets
$15.8
 
$24.6
 
$9.0
 
$16.1
 
$6.8
 
$8.5
Non-current derivative assets5.9
 3.7
 2.9
 1.6
 3.0
 2.1
Current derivative liabilities3.6
 5.6
 2.1
 3.1
 1.5
 2.5
Non-current derivative liabilities12.1
 17.7
 5.0
 8.1
 7.1
 9.6

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 March 31, 20182019 and December 31, 2017,2018, 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 March 31, 20182019 and December 31, 2017.2018. 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.


20
Table of Contents

NOTE 13. COMMITMENTS AND CONTINGENCIESFAIR VALUE MEASUREMENTS
NOTE 13(a) Capital Purchase ObligationsFair Value of Financial Instruments - Various contractual obligations contain minimum future commitmentsThe carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. Carrying amounts and related to capital expenditures for certain construction projects. IPL’s projects include the expansionestimated fair values of wind generation and installation of an SCR system at Ottumwa Unit 1 to reduce NOx emissions at the EGU. WPL’s projects include West Riverside. At March 31, 2018, Alliant Energy’s, IPL’s and WPL’s minimum future commitments related to certain contractual obligations for these projects were $95 million, $12 million and $83 million, respectively.

NOTE 13(b) Other Purchase Obligations - 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 obligations associated with other goods and services. At March 31, 2018, minimum future commitments related to these purchase obligationsfinancial instruments were as follows (in millions):
 Alliant Energy IPL WPL
Purchased power (a)
$1,175
 
$1,127
 
$48
Natural gas892
 362
 530
Coal (b)165
 88
 77
Other (c)46
 26
 6
 
$2,278
 
$1,603
 
$661
Alliant EnergyMarch 31, 2019 December 31, 2018
   Fair Value   Fair Value
 Carrying Level Level Level   Carrying Level Level Level  
 Amount 1 2 3 Total Amount 1 2 3 Total
Assets:                   
Derivatives
$21.7
 
$—
 
$15.9
 
$5.8
 
$21.7
 
$28.3
 
$—
 
$8.9
 
$19.4
 
$28.3
Deferred proceeds178.3
 —
 —
 178.3
 178.3
 119.4
 —
 —
 119.4
 119.4
Liabilities:                   
Derivatives15.7
 —
 10.3
 5.4
 15.7
 23.3
 —
 16.1
 7.2
 23.3
Long-term debt (incl. current maturities)5,618.7
 —
 6,071.6
 2.1
 6,073.7
 5,502.8
 —
 5,858.4
 2.4
 5,860.8
IPLMarch 31, 2019 December 31, 2018
   Fair Value   Fair Value
 Carrying Level Level Level   Carrying Level Level Level  
 Amount 1 2 3 Total Amount 1 2 3 Total
Assets:                   
Derivatives
$11.9
 
$—
 
$7.7
 
$4.2
 
$11.9
 
$17.7
 
$—
 
$4.0
 
$13.7
 
$17.7
Deferred proceeds178.3
 —
 —
 178.3
 178.3
 119.4
 —
 —
 119.4
 119.4
Liabilities:                   
Derivatives7.1
 —
 3.5
 3.6
 7.1
 11.2
 —
 6.5
 4.7
 11.2
Long-term debt2,667.8
 —
 2,852.4
 —
 2,852.4
 2,552.3
 —
 2,691.2
 —
 2,691.2
WPLMarch 31, 2019 December 31, 2018
   Fair Value   Fair Value
 Carrying Level Level Level   Carrying Level Level Level  
 Amount 1 2 3 Total Amount 1 2 3 Total
Assets:                   
Derivatives
$9.8
 
$—
 
$8.2
 
$1.6
 
$9.8
 
$10.6
 
$—
 
$4.9
 
$5.7
 
$10.6
Liabilities:                   
Derivatives8.6
 —
 6.8
 1.8
 8.6
 12.1
 —
 9.6
 2.5
 12.1
Long-term debt (incl. current maturities)1,835.4
 —
 2,080.0
 —
 2,080.0
 1,834.9
 —
 2,043.7
 —
 2,043.7

(a)Includes payments required by purchased power agreements for capacity rights and minimum quantities of MWhs required to be purchased.
(b)
Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of March 31, 2018 regarding expected future usage, which is subject to change.
(c)
Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2018.

Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions):
NOTE 13(c) Legal Proceedings -
Flood Damage Claims - In 2013, several plaintiffs purporting to represent a class of residential and commercial property owners filed a complaint against Cedar Rapids and Iowa City Railway Company (CRANDIC), Alliant Energy and various other defendants in the Iowa District Court for Linn County. Plaintiffs assert claims of negligence and strict liability based on their allegations that CRANDIC (along with other defendants) caused or exacerbated flooding of the Cedar River in June 2008. In February 2016, the Iowa District Court for Linn County ruled in favor of Alliant Energy and CRANDIC and dismissed all claims against them, resulting in no loss. In August 2016, the Iowa District Court for Linn County dismissed all claims against the remaining defendants. In September 2016, plaintiffs filed a notice of appeal with the Supreme Court of Iowa. Alliant Energy does not currently believe any material losses for this complaint are both probable and reasonably estimated, and therefore has not recognized any material loss contingency amounts as of March 31, 2018.

Alliant EnergyCommodity Contract Derivative  
 Assets and (Liabilities), net Deferred Proceeds
Three Months Ended March 312019 2018 2019 2018
Beginning balance, January 1
$12.2
 
($12.2) 
$119.4
 
$222.1
Total net losses included in changes in net assets (realized/unrealized)(5.6) (9.8) —
 —
Sales(0.2) —
 —
 —
Settlements (a)(6.0) (7.4) 58.9
 (101.2)
Ending balance, March 31
$0.4
 
($29.4) 
$178.3
 
$120.9
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at March 31
($2.6) 
($9.4) 
$—
 
$—

 2321 
Table of Contents

NOTE 13(d) Guarantees and Indemnifications -
IPLCommodity Contract Derivative  
 Assets and (Liabilities), net Deferred Proceeds
Three Months Ended March 312019 2018 2019 2018
Beginning balance, January 1
$9.0
 
($1.4) 
$119.4
 
$222.1
Total net losses included in changes in net assets (realized/unrealized)(3.2) (7.6) —
 —
Sales(0.1) —
 —
 —
Settlements (a)(5.1) (6.4) 58.9
 (101.2)
Ending balance, March 31
$0.6
 
($15.4) 
$178.3
 
$120.9
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at March 31
($1.4) 
($7.3) 
$—
 
$—
WPLCommodity Contract Derivative
 Assets and (Liabilities), net
Three Months Ended March 312019 2018
Beginning balance, January 1
$3.2
 
($10.8)
Total net losses included in changes in net assets (realized/unrealized)(2.4) (2.2)
Sales(0.1) —
Settlements(0.9) (1.0)
Ending balance, March 31
($0.2) 
($14.0)
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at March 31
($1.2) 
($2.1)

(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.

Whiting PetroleumCommodity Contracts - In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Whiting Petroleum is an independent oil and gas company. 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 general partnership agreements in the oil and gas industry, including with respect to the future abandonment of certain platforms off the coast of California and related onshore plant and equipment owned by the partnerships. The guarantees do not include a maximum limit. As of March 31, 2018, the presentfair value of the abandonment obligations is estimated at $34 million. Alliant Energy is not aware of any material liabilities related to these guarantees of which it is probable that Alliant Energy Resources, LLC will be obligated to payFTR and therefore has notnatural gas commodity contracts categorized as Level 3 was recognized any material liabilities related to this guarantee as of March 31, 2018.

Non-utility Wind Farm in Oklahoma - In July 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 purchased power agreement. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and purchased power agreement. Alliant Energy’s obligations under the operating agreement were $98 million as of March 31, 2018 and will reduce annually until expiring in July 2047. Alliant Energy’s obligations under the purchased power agreement 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 March 31, 2018.

IPL’s Minnesota Electric Distribution Assets - IPL provided indemnifications associated with the July 2015 sale of its Minnesota electric distributionnet derivative assets for losses resulting from potential breach of IPL’s representations, warranties and obligations under the sale agreement. Alliant Energy and IPL believe the likelihood of having to make any material cash payments under these indemnifications is remote. IPL has not recorded any material liabilities related to these indemnifications as of March 31, 2018. The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expire in October 2020.

NOTE 13(e) 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 March 31, 2018, 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(liabilities) as follows (in millions). At March 31, 2018, such amounts for WPL were not material.:
 Alliant Energy IPL
Range of estimated future costs
$11
-$30 
$9
-$25
Current and non-current environmental liabilities16 13

WPL Consent Decree - In 2013, the U.S. District Court for the Western District of Wisconsin approved a Consent Decree that WPL, along with the other owners of Edgewater and Columbia, entered into with the EPA and the Sierra Club, thereby resolving claims against WPL. Such claims included allegations that the owners of Edgewater, Nelson Dewey and Columbia violated the Prevention of Significant Deterioration program requirements, Title V Operating Permit requirements of the Clean Air Act (CAA) and the Wisconsin State Implementation Plan designed to implement the CAA.

WPL has completed various requirements under the Consent Decree. WPL’s remaining requirements include installing an SCR system at Columbia Unit 2 and fuel switching or retiring Edgewater Unit 4 by December 31, 2018. The Consent Decree also establishes sulfur dioxide (SO2), NOx and particulate matter emission rate limits for Columbia Units 1 and 2, and Edgewater Units 4 and 5. In addition, the Consent Decree includes annual plant-wide SO2 and NOx emission caps for Columbia and Edgewater. Alliant Energy and WPL currently expect to recover material costs incurred by WPL related to compliance with the terms of the Consent Decree from WPL’s electric customers.


24
Table of Contents

IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential CAA issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include installing an SCR system or equivalent NOx reduction system at Ottumwa by December 31, 2019, and fuel switching or retiring Burlington by December 31, 2021 and Prairie Creek Units 1 and 3 by December 31, 2025.

The Consent Decree also establishes SO2, NOx and particulate matter emission rate limits with varying averaging times for Burlington, Lansing, M.L. Kapp, Ottumwa and Prairie Creek. In addition, the Consent Decree includes calendar-year SO2 and NOx emission caps for Prairie Creek, and calendar-year SO2 and NOx emission caps in aggregate for Burlington, Lansing, M.L. Kapp, Ottumwa and Prairie Creek. 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: Cross-State Air Pollution Rule, Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including carbon emissions from new (CAA Section 111(b)) and existing (CAA Section 111(d)) fossil-fueled EGUs.
 Alliant Energy IPL WPL
 Excluding FTRs FTRs Excluding FTRs FTRs Excluding FTRs FTRs
March 31, 2019
($3.3) 
$3.7
 
($2.4) 
$3.0
 
($0.9) 
$0.7
December 31, 20183.2
 9.0
 1.8
 7.2
 1.4
 1.8

NOTE 14. SEGMENTS OF BUSINESSCOMMITMENTS AND CONTINGENCIES
In the fourth quarter of 2017, Alliant Energy and WPL modified the segment reportingNOTE 14(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to ATC Holdings, consistent with information used by their chief operating decision maker to evaluate performance and allocate resources. Ascapital expenditures for certain construction projects. IPL’s projects include the expansion of Decemberwind generation. WPL’s projects include the West Riverside Energy Center. At March 31, 2017, ATC Holdings are no longer included in2019, Alliant Energy’s, utility electric operations reportable segment orIPL’s and WPL’s electric operations reportable segment. As a result, all prior period amounts impacted by this changeminimum future commitments for these projects were reclassified to conform to the new presentation. Alliant Energy’s related amounts were reclassified from “Electric Utility” to “ATC Holdings, Non-Utility, Parent$65 million, $33 million and Other” in the table below. There was no resulting change to WPL’s segment reporting for the three months ended March 31, 2017.$32 million, respectively.

Alliant EnergyNOTE 14(b) Other Purchase Commitments - Certain financial information relatingVarious commodity supply, transportation and storage contracts help meet obligations to Alliant Energy’s business segments isprovide electricity and natural gas to utility customers. In addition, there are various purchase commitments associated with other goods and services. At March 31, 2019, the related minimum future commitments were as follows. Intersegment revenues were not material to Alliant Energy’s operations.follows (in millions):
         ATC Holdings,  
 Utility Non-Utility, Alliant Energy
 Electric Gas Other Total Parent and Other Consolidated
 (in millions)
Three Months Ended March 31, 2018           
Revenues
$708.7
 
$185.6
 
$13.2
 
$907.5
 
$8.8
 
$916.3
Operating income126.7
 31.5
 1.4
 159.6
 6.1
 165.7
Net income attributable to Alliant Energy common shareowners      100.7
 20.2
 120.9
Three Months Ended March 31, 2017           
Revenues
$677.6
 
$154.3
 
$11.7
 
$843.6
 
$10.3
 
$853.9
Operating income110.9
 28.6
 0.4
 139.9
 7.3
 147.2
Amounts attributable to Alliant Energy common shareowners:           
Income from continuing operations, net of tax      82.7
 16.3
 99.0
Income from discontinued operations, net of tax      —
 1.4
 1.4
Net income      82.7
 17.7
 100.4
 Alliant Energy IPL WPL
Purchased power (a)
$221
 
$219
 
$2
Natural gas879
 388
 491
Coal (b)163
 96
 67
Other (c)88
 49
 26
 
$1,351
 
$752
 
$586


 2522 
Table of Contents

(a)Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. As a result of amendments to shorten the term of the DAEC PPA, which were approved by the IUB and effective in January 2019, Alliant Energy’s and IPL’s amounts include minimum future commitments related to IPL’s purchase of capacity and the resulting energy from DAEC through September 2020, and do not include the September 2020 buyout payment of $110 million.
(b)Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of March 31, 2019 regarding expected future usage, which is subject to change.
(c)
Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2019.

NOTE 14(c) Guarantees and Indemnifications -
IPLWhiting Petroleum - Certain financial information relatingIn 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Whiting Petroleum is an independent oil and gas company. Alliant Energy Resources, LLC, as the successor to IPL’s business segmentsa 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 general partnership agreements in the oil and gas industry, including with respect to the future abandonment of certain platforms off the coast of California and related onshore plant and equipment owned by the partnerships. The guarantees do not include a maximum limit. As of March 31, 2019, the present value of the abandonment obligations is estimated at $37 million. Alliant Energy is not aware of any material liabilities related to these guarantees of which it is probable that Alliant Energy Resources, LLC will be obligated to pay and therefore has not recognized any material liabilities related to these guarantees as follows. Intersegment revenues were not material to IPL’s operations.of March 31, 2019 and December 31, 2018.
 Electric Gas Other Total
 (in millions)
Three Months Ended March 31, 2018       
Revenues
$405.7
 
$108.1
 
$12.0
 
$525.8
Operating income57.5
 16.9
 1.2
 75.6
Earnings available for common stock      46.7
Three Months Ended March 31, 2017       
Revenues
$356.2
 
$83.1
 
$11.2
 
$450.5
Operating income35.3
 14.6
 1.4
 51.3
Earnings available for common stock      37.2

WPLNon-utility Wind Farm in Oklahoma - Certain financial information relatingIn July 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 WPL’s business segmentsa 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 $90 million as of March 31, 2019 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 follows. Intersegment revenues were not material to WPL’s operations.of March 31, 2019 and December 31, 2018.
 Electric Gas Other Total
 (in millions)
Three Months Ended March 31, 2018       
Revenues
$303.0
 
$77.5
 
$1.2
 
$381.7
Operating income69.2
 14.6
 0.2
 84.0
Earnings available for common stock      54.0
Three Months Ended March 31, 2017       
Revenues
$321.4
 
$71.2
 
$0.5
 
$393.1
Operating income (loss)75.6
 14.0
 (1.0) 88.6
Earnings available for common stock      45.5

NOTE 15. RELATED PARTIES
Service AgreementsIPL’s Minnesota Electric Distribution Assets - PursuantIPL 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. Alliant Energy and IPL believe the likelihood of having to service agreements, make any material cash payments under these indemnifications is remote. IPL has not recorded any material liabilities related to these indemnifications as of March 31, 2019 and December 31, 2018. The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expire in October 2020.

NOTE 14(d) Environmental Matters -
Manufactured Gas Plant (MGP) Sites - IPL and WPL receivehave current or previous ownership interests in various administrative and general services from an affiliate, Corporate Services. These servicessites that are billed topreviously associated with the production of gas for which IPL and WPL at cost based on expenses incurred by Corporate Serviceshave, or may have in the future, liability for the benefit ofinvestigation, remediation and monitoring costs. 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 WPLare working pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services,requirements of various federal and transmission salestate agencies to investigate, mitigate, prevent and purchase transactions within MISO. Corporate Services assigns such salesremediate, where necessary, the environmental impacts to property, including natural resources, at and purchases among IPLaround these former MGP sites in order to protect public health and WPL based on statements received from MISO. The amounts billed for services provided, sales credited and purchasesthe environment. At March 31, 2019, estimated future costs expected to be incurred for the three months ended March 31investigation, 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 March 31, 2019, such amounts for WPL were not material.
 IPL WPL
 2018 2017 2018 2017
Corporate Services billings
$41
 
$39
 
$33
 
$31
Sales credited5
 2
 1
 —
Purchases billed93
 66
 17
 34

Net intercompany payables to Corporate Services were as follows (in millions):
 IPL WPL
 March 31, 2018 December 31, 2017 March 31, 2018 December 31, 2017
Net payables to Corporate Services$96 $114 $64 $61
 Alliant Energy IPL
Range of estimated future costs
$15
-$31 
$12
-$26
Current and non-current environmental liabilities19 16

ATCIPL Consent Decree - 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 betweenIn 2015, the partiesU.S. District Court for the three months ended March 31 were as follows (in millions):
 2018 2017
ATC billings to WPL
$27
 
$26
WPL billings to ATC2
 3

WPL owed ATC net amountsNorthern District of $7 million asIowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of March 31, 2018Iowa and $9 million as of 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, 20172021 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..


 2623 
Table of Contents


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 14(e) Collective Bargaining Agreements - At March 31, 2019, employees covered by collective bargaining agreements represented 55%, 62% and 82% of total employees of Alliant Energy, IPL and WPL, respectively. On May 31, 2019, WPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 965 expires, representing 26% and 82% of total employees of Alliant Energy and WPL, respectively. While negotiations to renew the agreement are underway, Alliant Energy and WPL are currently unable to predict the outcome.

NOTE 15. SEGMENTS OF BUSINESS
Alliant Energy - Certain financial information relating to Alliant Energy’s business segments is as follows. Intersegment revenues were not material to Alliant Energy’s operations.
         ATC Holdings, Alliant
 Utility Non-Utility, Energy
 Electric Gas Other Total Parent and Other Consolidated
 (in millions)
Three Months Ended March 31, 2019           
Revenues
$743.4
 
$215.8
 
$11.1
 
$970.3
 
$16.9
 
$987.2
Operating income126.4
 45.2
 —
 171.6
 5.2
 176.8
Net income attributable to Alliant Energy common shareowners      119.0
 6.1
 125.1
Three Months Ended March 31, 2018           
Revenues
$708.7
 
$185.6
 
$13.2
 
$907.5
 
$8.8
 
$916.3
Operating income126.7
 31.5
 1.4
 159.6
 6.1
 165.7
Net income attributable to Alliant Energy common shareowners      100.7
 20.2
 120.9

IPL - Certain financial information relating to IPL’s business segments is as follows. Intersegment revenues were not material to IPL’s operations.
 Electric Gas Other Total
 (in millions)
Three Months Ended March 31, 2019       
Revenues
$419.8
 
$124.6
 
$10.7
 
$555.1
Operating income46.8
 26.3
 0.4
 73.5
Earnings available for common stock      53.3
Three Months Ended March 31, 2018       
Revenues
$405.7
 
$108.1
 
$12.0
 
$525.8
Operating income57.5
 16.9
 1.2
 75.6
Earnings available for common stock      46.7


24
Table of Contents

WPL - Certain financial information relating to WPL’s business segments is as follows. Intersegment revenues were not material to WPL’s operations.
 Electric Gas Other Total
 (in millions)
Three Months Ended March 31, 2019       
Revenues
$323.6
 
$91.2
 
$0.4
 
$415.2
Operating income (loss)79.6
 18.9
 (0.4) 98.1
Earnings available for common stock      65.7
Three Months Ended March 31, 2018       
Revenues
$303.0
 
$77.5
 
$1.2
 
$381.7
Operating income69.2
 14.6
 0.2
 84.0
Earnings available for common stock      54.0

NOTE 16. 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 months ended March 31 were as follows (in millions):
 IPL WPL
 2019 2018 2019 2018
Corporate Services billings
$43
 
$41
 
$33
 
$33
Sales credited15
 5
 1
 1
Purchases billed84
 93
 30
 17

Net intercompany payables to Corporate Services were as follows (in millions):
 IPL WPL
 March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018
Net payables to Corporate Services$98 $95 $73 $71

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 months ended March 31 were as follows (in millions):
 Three Months
 2019 2018
ATC billings to WPL
$27
 
$27
WPL billings to ATC4
 2

WPL owed ATC net amounts of $7 million as of March 31, 2019 and $8 million as of December 31, 2018.

WPL’s Sheboygan Falls Energy Facility Lease - Refer to Note 7 for discussion of WPL’s Sheboygan Falls Energy Facility lease.

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 20172018 Form 10-K. Unless otherwise noted, all “per share” references in MDA refer to earnings per diluted share.

EXECUTIVE OVERVIEW

Description of Business
General - Alliant Energy is a Midwest U.S. energy holding company whose primary subsidiaries are IPL, WPL, AEF and Corporate Services. IPL and WPL are public utilities, and AEF is the parent company for Alliant Energy’s non-utility businesses, including Alliant Energy’s Transportation business and certain non-utility generation holdings, and holds all of Alliant Energy’s ATC Holdings. Corporate Services provides administrative services to Alliant Energy and its subsidiaries. An illustration of Alliant Energy’s primary businesses is shown below.
Alliant Energy
Utilities and Corporate ServicesATC Holdings, Non-utility and Parent
 - Retail electric and gas services in IA (IPL) - ATC Holdings (AEF)
 - Retail electric and gas services in WI (WPL) - Transportation (AEF)
 - Wholesale electric service in MN, IL & IA (IPL) - Non-utility wind farm (AEF)
 - Wholesale electric service in WI (WPL) - Sheboygan Falls Energy Facility (AEF)
 - Corporate Services - Parent Company

Financial Results - Alliant Energy’s net income and earnings per weighted average common share (EPS) attributable to Alliant Energy common shareowners for the first quarter were as follows (dollars in millions, except per share amounts):
 2018 2017
 Income EPS Income EPS
Continuing operations:       
Utilities and Corporate Services
$104.4
 
$0.45
 
$85.9
 
$0.38
ATC Holdings6.3
 0.03
 6.9
 0.03
Non-utility and Parent10.2
 0.04
 6.2
 0.02
Income from continuing operations120.9
 0.52
 99.0
 0.43
Income from discontinued operations—
 —
 1.4
 0.01
Net income
$120.9
 
$0.52
 
$100.4
 
$0.44

The table above includes EPS from continuing operations 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.

Alliant Energy’s, IPL’s and WPL’s income from continuing operations increased by $22 million, $10 million and $9 million, respectively, for the three-month period. Alliant Energy’s increase was primarily due to higher margins resulting from IPL’s interim retail electric base rate increase implemented in April 2017, and higher retail electric and gas sales due to colder temperatures in the first quarter of 2018 compared to the same period in 2017. These items were partially offset by higher depreciation expense.

Refer to “Results of Operations” for additional details regarding the various factors impacting earnings during the first quarters of 2018 and 2017.


 2725 
Table of Contents

2018 Overview - Alliant Energy, IPL and WPL continue to focus on achieving their financial objectives and executing their strategic plan. 2019 HIGHLIGHTS

Key developmentshighlights since the filing of the 20172018 Form 10-K include the following:

•
IPL’s and WPL’s Expansion of Wind Generation - In April 2018,March 2019, IPL received approval fromfiled requests with the IUB to increase annual base rates for advance rate-making principlesits Iowa retail electric and gas customers, which were based on a forward-looking test period that includes 2020. IPL concurrently filed for the second 500 MW of new wind generation. Ininterim retail electric rates based on a 2018 historical Test Year, which were implemented effective April 2018, WPL acquired 55 MW of FWEC, which is a 129 MW wind farm located in Wisconsin.1, 2019. Refer to “Strategic OverviewNote 2” for further discussion.details.
IPL’s Tax Reform Benefits - In April 2018,March 2019, IPL placed approximately 470 megawatts of new wind generation in service at the IUB issued an order approving the return of approximately $35 million of estimated annual tax benefits for 2018 toUpland Prairie and English Farms wind sites. IPL’s retail electric customers utilizingbegan to see the tax benefit riderimpacts of this renewable generation with the interim electric rates effective MayApril 1, 2018, subject to true-up. The IUB order also approved the return of approximately $3 million of estimated annual tax benefits for 2018 to IPL’s retail gas customers utilizing interim rates to be implemented May 14, 2018 for IPL’s 2017 Test Year gas rate review, subject to further review by the IUB. Lastly,2019.
In March 2019, the IUB order determined the excess deferred taxes resulting from the remeasurement of accumulated deferred income taxes caused by Tax Reform (approximately $370 million revenue requirement) will be addressed inapproved IPL’s next retail electricenergy efficiency plan for 2019 through 2023, which provides direct financial savings to customers and gas rate reviews.
WPL’s Tax Reform Benefits - In April 2018, WPL received a decision from the PSCW directing WPLprovides cost-effective options to return annual tax benefits for 2018 to WPL’s retailhelp electric and gas customers reduce their energy usage. The energy efficiency costs, which WPL currently estimates toare lower than previous energy efficiency plans, will be approximately $43 million. reflected on customer bills beginning June 2019.
•
In January and March 2019, AEF, a subsidiary of Alliant Energy, purchased two freight management companies. These non-utility acquisitions enhance Alliant Energy’s Transportation value to customers by adding customized supply chain solution capabilities to their portfolio of service offerings. Refer to Note 4 for details.
The estimated tax benefits related toinstallation of a selective catalytic reduction system at IPL’s Ottumwa Unit 1 was completed in the first halfquarter of 2018 will be provided2019, which supports compliance obligations under the Cross-State Air Pollution Rule and IPL’s Consent Decree.
In April 2019, IPL issued $300 million of 3.6% senior debentures due 2029. The senior debentures were issued as a one-time credit on WPL’s retail electricgreen bonds, and gas customers’ July 2018 bills. Thereafter, WPL currently expects to provide a monthly refund equal to one-twelfthall of the estimated annual tax benefits for 2018 to its retail electric and gas customers through the end of 2018. The PSCW decision also determined the excess deferred taxes resulting from the remeasurement of accumulated deferred income taxes caused by Tax Reform (approximately $460 million revenue requirement) will be addressed in WPL’s next retail electric and gas rate review.
IPL’s Retail Gas Rate Review (2017 Test Year) - In May 2018, IPL filed a request with the IUB to increase annual gas base rates for its Iowa retail gas customers by $20 million, or approximately 8%. The request was based on a 2017 historical Test Year as adjusted for certain known and measurable changes occurring up to 12 months after the commencement of the proceeding. The key driversnet proceeds were allocated for the filing included recoveryconstruction and development of capital projects, partially offset by the benefits of Tax Reform. An interim retail gas rate increase of $11 million, or approximately 5%, on an annual basis, will be implemented effective May 14, 2018. IPL currently expects a decision from the IUB in 2019 with final rates effective by the second quarter of 2019.
IPL’s wind projects.

RESULTS OF OPERATIONS

Overview - “Executive Overview” provides an overview of Alliant Energy’s, IPL’s and WPL’s earnings for the three months ended March 31, 2018 and 2017. Additional earnings details for the three months ended March 31, 2018 and 2017 are discussed below.

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

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

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

Financial Results Overview - Alliant Energy’s net income and EPS attributable to Alliant Energy common shareowners for the first quarter were as follows (dollars in millions, except per share amounts):
 2019 2018
 Income (Loss) EPS Income EPS
Utilities and Corporate Services
$122.0
 
$0.52
 
$104.4
 
$0.45
ATC Holdings7.1
 0.03
 6.3
 0.03
Non-utility and Parent(4.0) (0.02) 10.2
 0.04
Alliant Energy Consolidated
$125.1
 
$0.53
 
$120.9
 
$0.52

Alliant Energy’s Utilities and Corporate Services net income increased by $18 million for the three-month period, primarily due to higher margins resulting from IPL’s and WPL’s increasing rate base and higher retail electric and gas sales due to

 2826 
Table of Contents

colder temperatures in the first quarter of 2019 compared to the same period in 2018. These items were partially offset by higher depreciation expense.

Alliant Energy’s Non-utility and Parent net income decreased by $14 million for the three-month period, primarily due to higher interest expense and lower equity income from the wind farm in Oklahoma due to accelerated earnings in the first quarter of 2018 as a result of Federal Tax Reform, which is expected to reverse over time.

For the three months ended March 31, 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 WPLAlliant Energy IPL WPL
Three Months2018 2017 2018 2017 2018 20172019 2018 2019 2018 2019 2018
Operating income
$165.7
 
$147.2
 
$75.6
 
$51.3
 
$84.0
 
$88.6

$176.8
 
$165.7
 
$73.5
 
$75.6
 
$98.1
 
$84.0
                      
Electric utility revenues
$708.7
 
$677.6
 
$405.7
 
$356.2
 
$303.0
 
$321.4

$743.4
 
$708.7
 
$419.8
 
$405.7
 
$323.6
 
$303.0
Electric production fuel and purchased power expenses(203.2) (207.8) (114.6) (109.5) (88.6) (98.3)(218.4) (203.2) (128.9) (114.6) (89.5) (88.6)
Electric transmission service expense(126.4) (124.7) (90.8) (81.7) (35.6) (43.0)(123.0) (126.4) (87.7) (90.8) (35.3) (35.6)
Utility Electric Margin (non-GAAP)379.1
 345.1
 200.3
 165.0
 178.8
 180.1
402.0
 379.1
 203.2
 200.3
 198.8
 178.8
                      
Gas utility revenues185.6
 154.3
 108.1
 83.1
 77.5
 71.2
215.8
 185.6
 124.6
 108.1
 91.2
 77.5
Cost of gas sold(111.2) (92.2) (60.6) (47.8) (50.6) (44.4)(121.6) (111.2) (63.3) (60.6) (58.3) (50.6)
Utility Gas Margin (non-GAAP)74.4
 62.1
 47.5
 35.3
 26.9
 26.8
94.2
 74.4
 61.3
 47.5
 32.9
 26.9
                      
Other utility revenues13.2
 11.7
 12.0
 11.2
 1.2
 0.5
11.1
 13.2
 10.7
 12.0
 0.4
 1.2
Non-utility revenues8.8
 10.3
 —
 —
 —
 —
16.9
 8.8
 —
 —
 —
 —
Other operation and maintenance expenses(162.4) (148.6) (105.5) (93.2) (56.3) (54.4)(181.2) (162.4) (108.0) (105.5) (63.5) (56.3)
Depreciation and amortization expenses(120.4) (107.0) (64.8) (53.6) (54.6) (52.4)(136.9) (120.4) (77.1) (64.8) (58.6) (54.6)
Taxes other than income tax expense(27.0) (26.4) (13.9) (13.4) (12.0) (12.0)(29.3) (27.0) (16.6) (13.9) (11.9) (12.0)
Operating income
$165.7
 
$147.2
 
$75.6
 
$51.3
 
$84.0
 
$88.6

$176.8
 
$165.7
 
$73.5
 
$75.6
 
$98.1
 
$84.0

Operating Income Variances - Variances between periods in operating income for the three months ended March 31, 20182019 compared to the same period in 20172018 were as follows (in millions):
 Alliant Energy IPL WPL
Total higher (lower) utility electric margin variance (refer to details below)
$34
 
$35
 
($1)
Total higher utility gas margin variance (refer to details below)12
 12
 —
Total higher other operation and maintenance expenses variance (refer to details below)(14) (12) (2)
Total higher depreciation and amortization expense, primarily due to additional plant in service in 2017, including impacts from the Marshalltown Generating Station(13) (11) (2)
 
$19
 
$24
 
($5)
 Alliant Energy IPL WPL
Total higher utility electric margin variance (Refer to details below)
$23
 
$3
 
$20
Total higher utility gas margin variance (Refer to details below)20
 14
 6
Higher non-utility revenues due to AEF’s new acquisitions8
 —
 —
Total higher other operation and maintenance expenses variance (Refer to details below)(19) (3) (7)
Higher depreciation and amortization expense, primarily due to new IPL depreciation rates effective May 2018 and additional plant in service in 2018 and 2019(17) (12) (4)
Other(4) (4) (1)
 
$11
 
($2) 
$14

Electric and Gas Revenues and Sales Summary - Electric and gas revenues (in millions), and MWh and Dth sales (in thousands), for the three months ended March 31 were as follows:
Alliant EnergyElectric GasElectric Gas
Revenues MWhs Sold Revenues Dths SoldRevenues MWhs Sold Revenues Dths Sold
2018 2017 2018 2017 2018 2017 2018 20172019 2018 2019 2018 2019 2018 2019 2018
Retail
$635.3
 
$601.9
 6,336
 6,193
 
$173.4
 
$144.5
 23,848
 20,560

$664.5
 
$635.3
 6,352
 6,336
 
$200.8
 
$173.4
 26,379
 23,848
Sales for resale60.6
 64.4
 1,121
 1,051
 —
 —
 —
 —
63.5
 60.6
 1,424
 1,121
 N/A
 N/A
 N/A
 N/A
Transportation/Other12.8
 11.3
 26
 26
 12.2
 9.8
 24,061
 19,108
15.4
 12.8
 26
 26
 15.0
 12.2
 25,370
 24,061

$708.7
 
$677.6
 7,483
 7,270
 
$185.6
 
$154.3
 47,909
 39,668

$743.4
 
$708.7
 7,802
 7,483
 
$215.8
 
$185.6
 51,749
 47,909
IPLElectric Gas
 Revenues MWhs Sold Revenues Dths Sold
 2018 2017 2018 2017 2018 2017 2018 2017
Retail
$368.6
 
$326.7
 3,669
 3,553
 
$99.8
 
$76.5
 12,692
 10,792
Sales for resale29.7
 22.3
 527
 350
 —
 —
 —
 —
Transportation/Other7.4
 7.2
 9
 10
 8.3
 6.6
 11,223
 10,740
 
$405.7
 
$356.2
 4,205
 3,913
 
$108.1
 
$83.1
 23,915
 21,532
WPLElectric Gas
IPLElectric Gas
Revenues MWhs Sold Revenues Dths SoldRevenues MWhs Sold Revenues Dths Sold
2018 2017 2018 2017 2018 2017 2018 20172019 2018 2019 2018 2019 2018 2019 2018
Retail
$266.7
 
$275.2
 2,667
 2,640
 
$73.6
 
$68.0
 11,156
 9,768

$380.2
 
$368.6
 3,629
 3,669
 
$115.9
 
$99.8
 13,993
 12,692
Sales for resale30.9
 42.1
 594
 701
 —
 —
 —
 —
32.0
 29.7
 927
 527
 N/A
 N/A
 N/A
 N/A
Transportation/Other5.4
 4.1
 17
 16
 3.9
 3.2
 12,838
 8,368
7.6
 7.4
 9
 9
 8.7
 8.3
 11,007
 11,223

$303.0
 
$321.4
 3,278
 3,357
 
$77.5
 
$71.2
 23,994
 18,136

$419.8
 
$405.7
 4,565
 4,205
 
$124.6
 
$108.1
 25,000
 23,915

 2927 
Table of Contents

WPLElectric Gas
 Revenues MWhs Sold Revenues Dths Sold
 2019 2018 2019 2018 2019 2018 2019 2018
Retail
$284.3
 
$266.7
 2,723
 2,667
 
$84.9
 
$73.6
 12,386
 11,156
Sales for resale31.5
 30.9
 497
 594
 N/A
 N/A
 N/A
 N/A
Transportation/Other7.8
 5.4
 17
 17
 6.3
 3.9
 14,363
 12,838
 
$323.6
 
$303.0
 3,237
 3,278
 
$91.2
 
$77.5
 26,749
 23,994

Sales Trends and Temperatures - Heating degree days (HDD) are calculated using a simple average ofAlliant Energy’s retail electric sales volumes remained unchanged for the high and low temperatures each daythree months ended March 31, 2019 compared to a 65 degree base. Normal degree days are calculated using a rolling 20-year average of historical HDD. The following table summarizes the approximate quarterly temperature statistics and resulting impacts on IPL’s and WPL’s electric and gas sales.same period in 2018. Increases related to changes in temperatures in Alliant Energy’s service territories were offset by lower industrial sales at IPL.
 2018 2017 Resulting Impact in 2018 Compared to 2017
First quarter (HDD)2% colder than normal 13% warmer than normal Increase in IPL’s and WPL’s electric and gas sales due to higher demand by customers for heating

Estimated increases (decreases) to electric and gas margins from the impacts of temperatures for the three months ended March 31 were as follows (in millions):
Electric Margins Gas MarginsElectric Margins Gas Margins
2018 2017 Change 2018 2017 Change2019 2018 Change 2019 2018 Change
IPL
$—
 
($5) 
$5
 
$—
 
($3) 
$3

$6
 
$—
 
$6
 
$3
 
$—
 
$3
WPL1
 (4) 5
 1
 (2) 3
4
 1
 3
 2
 1
 1
Total Alliant Energy
$1
 
($9) 
$10
 
$1
 
($5) 
$6

$10
 
$1
 
$9
 
$5
 
$1
 
$4

Utility Electric Margin Variances - The following items contributed to increased (decreased) utility electric margins for the three months ended March 31, 20182019 compared to the same period in 20172018 as follows (in millions):
 Alliant Energy IPL WPL
Higher margins at IPL from the impact of its 2016 Test Year interim retail electric base rate increase (Refer to Note 2 for details)

$23
 
$23
 
$—
Higher revenues at IPL due to electric tax benefit rider credits on customers’ bills in 201717
 17
 —
Estimated changes in sales volumes caused by temperatures (Refer to “Temperatures” above for details)10
 5
 5
Changes in electric fuel-related costs, net of recoveries at WPL (a)6
 —
 6
Lower transmission cost recovery amortization at WPL (b)6
 —
 6
Decrease in revenues due to deferral of higher taxes collected to be returned to customers (deferral is offset by lower tax expense from the effects of Tax Reform) (Refer to Note 2 for details)
(17) (7) (10)
Lower wholesale margins at WPL primarily due to the expiration of a wholesale power supply agreement on May 31, 2017(7) —
 (7)
Other(4) (3) (1)
 
$34
 
$35
 
($1)

(a)
WPL estimates the decrease to electric margins from amounts within the approved bandwidth of plus or minus 2% of forecasted fuel-related expenses determined by the PSCW each year was approximately $6 million for the three months ended March 31, 2017. The impact to electric margins from amounts within the bandwidth was not material for the three months ended March 31, 2018.
(b)The December 2016 PSCW order for WPL’s 2017/2018 Test Period electric and gas base rate review authorized changes in electric transmission cost recovery amortizations for 2018.

Electric Sales Trends - Alliant Energy’s retail electric sales volumes increased 2% for the three months ended March 31, 2018 compared to the same period in 2017. The increase was primarily due to the impact of higher residential and commercial sales due to colder temperatures during the three months ended March 31, 2018 compared to the same period in 2017.
 Alliant Energy IPL WPL
Higher margins at WPL from earning on increasing rate base for rates effective January 2019
$13
 
$—
 
$13
Estimated changes in sales volumes caused by temperatures9
 6
 3
Impact of IPL’s retail electric final base rate increase effective May 20186
 6
 —
Lower revenues at IPL due to changes in electric tax benefit rider credits on customers’ bills (offset by changes in income tax expense)(5) (5) —
Other—
 (4) 4
 
$23
 
$3
 
$20

Utility Gas Margin Variances - The following items contributed to increased (decreased) utility gas margins for the three months ended March 31, 20182019 compared to the same period in 20172018 as follows (in millions):
 Alliant Energy IPL WPL
Higher revenues at IPL related to changes in recovery amounts for energy efficiency costs through the energy efficiency rider (mostly offset by changes in energy efficiency expense included in other operation and maintenance expenses)
$7
 
$7
 
$—
Estimated changes in sales volumes caused by temperatures (Refer to “Temperatures” above for details)6
 3
 3
Other(1) 2
 (3)
 
$12
 
$12
 
$—

30
Table of Contents

 Alliant Energy IPL WPL
Impact of IPL’s retail gas final base rate increase effective January 2019
$7
 
$7
 
$—
Estimated changes in sales volumes caused by temperatures4
 3
 1
Higher revenues at IPL related to changes in recovery amounts for energy efficiency costs through the energy efficiency rider (mostly offset by changes in energy efficiency expense)3
 3
 —
Higher margins at WPL from earning on increasing rate base for rates effective January 20192
 —
 2
Other4
 1
 3
 
$20
 
$14
 
$6

Other Operation and Maintenance Expenses Variances - The following items contributed to (increased) decreased other operation and maintenance expenses for the three months ended March 31, 20182019 compared to the same period in 20172018 as follows (in millions):
 Alliant Energy IPL WPL
Higher energy efficiency expense at IPL (primarily offset by gas revenues)
($6) 
($6) 
$—
Higher generation operation and maintenance expenses, primarily due to the Marshalltown Generating Station and timing of expenditures(5) (3) (2)
Other(3) (3) —
 
($14) 
($12) 
($2)
 Alliant Energy IPL WPL
Higher operation expense at AEF due to new acquisitions (offset by higher non-utility revenues)
($7) 
$—
 
$—
Higher energy efficiency expense at IPL (primarily offset by higher gas revenues)(4) (4) —
Higher energy efficiency cost recovery amortizations at WPL pursuant to authorization from Public Service Commission of Wisconsin rate order effective January 2019(4) —
 (4)
Other(4) 1
 (3)
 
($19) 
($3) 
($7)


28
Table of Contents

Other Income and Deductions Variances - The following items contributed to (increased) decreased other income and deductions for the three months ended March 31, 20182019 compared to the same period in 20172018 as follows (in millions):
Alliant Energy IPL WPLAlliant Energy IPL WPL
Higher interest expense primarily due to higher average outstanding long-term debt balances
($7) 
($2) 
($2)
($7) 
$—
 
($1)
Higher (lower) AFUDC primarily due to increased (decreased) construction work in progress balances(2) (7) 5
Higher equity income primarily related to increased earnings from the non-utility wind farm in Oklahoma (Refer to Note 5 for details)
10
 —
 —
Lower equity income primarily due to decreased earnings from non-utility wind farm resulting from an acceleration of earnings in the first quarter of 2018 due to Federal Tax Reform(10) —
 —
Higher allowance for funds used during construction primarily due to increased construction work in progress balances related to IPL’s new wind generation and WPL’s West Riverside Energy Center11
 8
 2
Other2
 1
 1
(3) —
 —

$3
 
($8) 
$4

($9) 
$8
 
$1

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

STRATEGIC OVERVIEW

The strategic overview summary included in the 2017 Form 10-K has not changed materially, except as described below.

Generation Plans -
Wind Generation -
IPL’s Expansion of Wind Generation - In April 2018, IPL received approval from the IUB for advance rate-making principles for up to 500 MW of new wind generation, which is in addition to the 500 MW of new generation approved by the IUB in October 2016. The April 2018 IUB decision approved IPL’s requested advance rate-making principles, except for the return on common equity for the calculation of AFUDC during the construction period. IPL requested a return that was the greater of 10.0% or whatever percentage the IUB finds reasonable during IPL’s most recent retail electric rate proceeding, and the IUB approved a return of 9.6%.

WPL’s Expansion of Wind Generation - Refer to Note 3 for discussion of WPL’s April 2018 acquisition of 55 MW of the Forward Wind Energy Center.

Coal-Fired Generation -
Plant Retirement - Refer to “Critical Accounting Policies and Estimates” for discussion of the expected retirement of IPL’s M.L. Kapp Unit 2 by June 1, 2018.

RATE MATTERS

The rate matters summary included in the 2017 Form 10-K has not changed materially, except as described below.


31
Table of Contents

Retail Base Rate Filings -
IPL’s Retail Gas Rate Review (2017 Test Year) - In May 2018, IPL filed a request with the IUB to increase annual gas base rates for its Iowa retail gas customers by $20 million, or approximately 8%. The request was based on a 2017 historical Test Year as adjusted for certain known and measurable changes occurring up to 12 months after the commencement of the proceeding. The key drivers for the filing included recovery of capital projects, partially offset by the benefits of Tax Reform. An interim retail gas rate increase of $11 million, or approximately 5%, on an annual basis, will be implemented effective May 14, 2018. The interim rate increase does not require regulatory approval; however, it will be subject to refund pending determination of final rates. IPL currently expects a decision from the IUB in 2019 with final rates effective by the second quarter of 2019. The IUB must issue a decision on requests for retail rate changes within 10 months of the date of the application for which changes are filed. The requested interim and final rate increases were calculated based on the following:
 Interim Rates Final Rates
Regulatory capital structure:   
Common equity (CE)49.6% 53.0%
Long-term debt (LD)46.5% 43.2%
Preferred equity3.9% 3.8%
After-tax weighted-average cost of capital (WACC)7.4% 7.5%
Return on common equity (ROE)9.8% 9.8%
Retail gas rate base (a)$460 million $509 million

(a)The retail gas rate base for interim rates includes post-test year capital additions placed in service prior to the rate filing in May 2018. The proposed retail gas rate base for final rates also includes post-test year capital additions expected to be placed in service by September 30, 2018.

IPL’s Retail Electric Rate Review (2016 Test Year) - Refer to Note 2 for discussion of IPL’s final annual retail electric rate increase for the 2016 Test Year, which was effective May 1, 2018.

Tax Reform - In January 2018, the IUB issued an order requiring IPL and other investor-owned utilities in Iowa to track all calculated differences since January 1, 2018 resulting from Tax Reform. In April 2018, the IUB issued an order on IPL’s electric and gas Tax Reform proposals. The IUB order approved the return of approximately $35 million of estimated annual tax benefits for 2018 to IPL’s retail electric customers utilizing the tax benefit rider effective May 1, 2018. These benefits are subject to true-up. The IUB order also approved the return of approximately $3 million of estimated annual tax benefits for 2018 to IPL’s retail gas customers utilizing interim rates to be implemented May 14, 2018 for IPL’s 2017 Test Year gas rate review. These benefits are subject to further review by the IUB. Lastly, the IUB order determined the excess deferred taxes resulting from the remeasurement of accumulated deferred income taxes caused by Tax Reform (approximately $370 million revenue requirement) will be addressed in IPL’s next retail electric and gas rate reviews.

In January 2018, the PSCW issued an order directing WPL and other investor-owned utilities in Wisconsin to defer the revenue requirement impacts since January 1, 2018 resulting from Tax Reform. In April 2018, WPL received a decision from the PSCW directing WPL to return annual tax benefits for 2018 to WPL’s retail electric and gas customers, which WPL currently estimates to be approximately $43 million. The estimated tax benefits related to the first half of 2018 will be provided as a one-time credit on WPL’s retail electric and gas customers’ July 2018 bills. Thereafter, WPL currently expects to provide a monthly refund equal to one-twelfth of the estimated annual tax benefits for 2018 to its retail electric and gas customers through the end of 2018. These billing credits are subject to true-up. The PSCW decision also determined the excess deferred taxes resulting from the remeasurement of accumulated deferred income taxes caused by Tax Reform (approximately $460 million revenue requirement) will be addressed in WPL’s next retail electric and gas rate review.

In March 2018, FERC issued an order granting a waiver request filed in February 2018 by a group of MISO transmission owners, including ITC Midwest LLC and ATC, allowing transmission rates to be updated to reflect the impacts resulting from Tax Reform. As a result, beginning in March 2018, amounts billed by ITC Midwest LLC and ATC decreased due to the impacts from Tax Reform. IPL and WPL currently expect lower electric transmission service expense of approximately $35 million and $10 million, respectively, in 2018 due to Tax Reform. IPL began providing the benefits of the lower transmission service expenses to its electric customers utilizing the transmission cost recovery mechanism effective May 1, 2018. WPL will defer the benefits of the lower transmission service expenses from Tax Reform until a future electric rate review. Based on IPL’s and WPL’s electric transmission cost recovery mechanisms, they currently do not expect that any changes to electric transmission service costs billed by ITC Midwest LLC and ATC, respectively, will have a material impact on their financial condition and results of operations.


32
Table of Contents

LIQUIDITY AND CAPITAL RESOURCES

The liquidity and capital resources matters summary included in the 20172018 Form 10-K has not changed materially, except as described below.

Liquidity Position - At March 31, 2018,2019, Alliant Energy had $19$10 million of cash and cash equivalents, $618$370 million ($9573 million at the parent company, $204$135 million at IPL and $319$162 million at WPL) of available capacity under the single revolving credit facility and no$21 million of available capacity at IPL under its sales of accounts receivable program.

Capital Structure - Capital structures at March 31, 20182019 were as follows (Long-term Debt (including current maturities) (LD); Short-term Debt (SD); Common Equity (CE); IPL’s Preferred Stock (PS)):
chart-0bc25d3d26745f7d9a5a01.jpgchart-3273d951649154e59f1a01.jpgchart-ebced145bcd256e08d5a01.jpg
Tax Reform - Refer to “Rate Matters” for discussion of expected refunds in 2018 to IPL’s and WPL’s retail electric and gas customers related to tax benefits resulting from Tax Reform.

chart-f1f97190ddbf5e9dbcaa03.jpgchart-2229ac54420d5ee0812a03.jpgchart-068689474efe501585ba03.jpg
Cash Flows - Selected information from the cash flows statements was as follows (in millions):
Alliant Energy IPL WPLAlliant Energy IPL WPL
2018 2017 2018 2017 2018 20172019 2018 2019 2018 2019 2018
Cash, cash equivalents and restricted cash, January 1
$33.9
 
$13.1
 
$7.2
 
$4.2
 
$24.2
 
$6.9

$25.5
 
$33.9
 
$12.4
 
$7.2
 
$9.2
 
$24.2
Cash flows from (used for):                      
Operating activities89.3
 119.0
 (65.2) (38.4) 141.7
 145.6
181.1
 156.3
 76.7
 1.8
 122.2
 141.7
Investing activities(85.2) (87.2) 55.6
 78.4
 (128.7) (149.3)(364.8) (152.2) (221.8) (11.4) (120.3) (128.7)
Financing activities(9.8) (29.9) 8.9
 (39.2) (31.3) 1.6
176.0
 (9.8) 139.6
 8.9
 (6.4) (31.3)
Net increase (decrease)(5.7) 1.9
 (0.7) 0.8
 (18.3) (2.1)(7.7) (5.7) (5.5) (0.7) (4.5) (18.3)
Cash, cash equivalents and restricted cash, March 31
$28.2
 
$15.0
 
$6.5
 
$5.0
 
$5.9
 
$4.8

$17.8
 
$28.2
 
$6.9
 
$6.5
 
$4.7
 
$5.9


29
Table of Contents

Operating Activities - The following items contributed to increased (decreased) operating activity cash flows for the three months ended March 31, 20182019 compared to the same period in 20172018 (in millions):
 Alliant Energy IPL WPL
Refunds received from ITC Midwest LLC and ATC in 2017
($51) 
($40) 
($11)
Higher collections at IPL due to interim retail electric base rate increase effective April 13, 201723
 23
 —
Other (primarily due to other changes in working capital)(2) (10) 7
 
($30) 
($27) 
($4)
 Alliant Energy IPL WPL
Changes in levels of production fuel
$19
 
$16
 
$3
Increased collections from IPL’s and WPL’s retail customers caused by temperature impacts on electric and gas sales13
 9
 4
Higher collections from IPL’s retail electric and gas base rate increases13
 13
 —
Amounts refunded to customers in 2019 related to Federal Tax Reform(11) (9) (2)
Timing of intercompany payments and receipts—
 21
 (2)
Other (primarily due to other changes in working capital)(9) 25
 (23)
 
$25
 
$75
 
($20)

Investing Activities - The following items contributed to increased (decreased) investing activity cash flows for the three months ended March 31, 20182019 compared to the same period in 20172018 (in millions):
Alliant Energy IPL WPLAlliant Energy IPL WPL
Changes in the amount of cash receipts on sold receivables
($164) 
($164) 
$—
Lower (higher) utility construction expenditures (a)
($66) 
($91) 
$24
(39) (43) 4
Changes in the amount of cash receipts on sold receivables70
 70
 —
Other(2) (2) (3)(10) (3) 4

$2
 
($23) 
$21

($213) 
($210) 
$8

(a)Largely due to higher expenditures for IPL’s expansion of wind generation and IPL’s advanced metering infrastructure, partially offset by lower expenditures for IPL’s Marshalltown Generating Station and WPL’s electric and gas distribution systems.generation.


33
Table of Contents

Financing Activities - The following items contributed to increased (decreased) financing activity cash flows for the three months ended March 31, 20182019 compared to the same period in 20172018 (in millions):
 Alliant Energy IPL WPL
Changes in outstanding checks that have not yet cleared the bank
$23
 
$15
 
$4
Net changes in the amount of commercial paper outstanding3
 37
 (33)
Other (includes higher dividend payments in 2018)(6) (4) (4)
 
$20
 
$48
 
($33)
 Alliant Energy IPL WPL
Net changes in the amount of commercial paper outstanding
$126
 
$19
 
$27
Higher net proceeds from common stock issuances48
 —
 —
Higher capital contributions from IPL’s parent company, Alliant Energy—
 100
 —
Other12
 12
 (2)
 
$186
 
$131
 
$25

Common Stock Issuances- Refer to Note 65 for discussion of common stock issuances by Alliant Energy during the three months ended March 31, 2018.2019.

Short- and Long-term Debt - Refer to Note 7(b)6 for discussion of $45.9 millionamendments to the single credit facility agreement in March 2019 and IPL’s issuance of commercial paper outstanding at March 31, 2018 classified as long-term debt at Alliant Energy and IPL, as well as a $300 million variable-rate term loan credit agreement AEF entered into in April 2018 (with Alliant Energy as guarantor).2019.

Off-Balance Sheet Arrangements - A summary of Alliant Energy’s off-balance sheet arrangements is included in the 20172018 Form 10-K and has not changed materially from the items reported in the 20172018 Form 10-K, except asfor the items described below. Refer toin Note 43 for information regarding IPL’s sales of accounts receivable program..

Certain Financial Commitments -
Contractual Obligations - A summary of Alliant Energy’s, IPL’s and WPL’s contractual obligations is included in the 20172018 Form 10-K and has not changed materially from the items reported in the 20172018 Form 10-K, except for the items described in Notes 7(b)6, 13(a)7 and 13(b)14.

OTHER MATTERS

New Accounting Standards - Refer to Note 1(d) for discussion of new accounting standards impacting Alliant Energy, IPL and WPL.

Critical Accounting Policies and Estimates - The summary of critical accounting policies and estimates included in the 2017 Form 10-K has not changed materially, except as described below.

Long-Lived Assets -
Regulated Operations -
Generating Units Subject to Early Retirement - IPL currently expects to retire M.L. Kapp Unit 2 by June 1, 2018, which had a net book value of $30 million as of March 31, 2018. Alliant Energy and IPL concluded that M.L. Kapp Unit 2 met the criteria to be considered probable of abandonment as of March 31, 2018. IPL is currently allowed a full recovery of and a full return on this EGU from both its retail and wholesale customers, and as a result, Alliant Energy and IPL concluded that no impairment was required as of March 31, 2018.

ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

Quantitative and Qualitative Disclosures About Market Risk are reported in the 20172018 Form 10-K and have not changed materially.


30
Table of Contents

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 March 31, 20182019 pursuant to the requirements of the Securities Exchange Act of 1934, as amended. Based on their evaluation, the Chief Executive OfficerOfficers 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 March 31, 2018.2019.

There was no change in Alliant Energy’s, IPL’s and WPL’s internal control over financial reporting that occurred during the quarter ended March 31, 20182019 that has materially affected, or is reasonably likely to materially affect, Alliant Energy’s, IPL’s or WPL’s internal control over financial reporting.


34
Table of Contents

PART II. OTHER INFORMATION

ITEM 1A. RISK FACTORS

The risk factors described in Item 1A in the 20172018 Form 10-K have not changed materially.

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

A summary of Alliant Energy common stock repurchases for the quarter ended March 31, 20182019 was as follows:
 Total Number Average Price Total Number of Shares Maximum Number (or Approximate 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 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) Purchased (a) Share Publicly Announced Plan Yet Be Purchased Under the Plan (a)
January 1 through January 31 3,840
 
$39.84
 — N/A 2,138
 
$42.51
 — N/A
February 1 through February 28 42,509
 38.65
 — N/A 3,122
 45.00
 — N/A
March 1 through March 31 1,175
 38.77
 — N/A 4,263
 46.31
 — N/A
 47,524
 38.74
 —  9,523
 45.03
 — 

(a)Includes 3,840, 4,0862,138, 3,122 and 1,1751,525 shares of Alliant Energy common stock for January 1 through January 31, February 1 through February 28 and March 1 through March 31, respectively, 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. Also includes 38,4232,738 shares of Alliant Energy common stock for FebruaryMarch 1 through February 28March 31 transferred from employees to Alliant Energy to satisfy tax withholding requirements in connection with the vesting of certain restricted stock under equity-based compensation plans.

Refer to
31
Note 6 for discussion
Table of IPL’s and WPL’s dividend restrictions and limitations on distributions to their parent company, Alliant Energy.Contents

ITEM 6. EXHIBITS

The following Exhibits are filed herewith or incorporated herein by reference.
Exhibit Number Description
3.14.1 
Amended and Restated BylawsOfficer’s Certificate, dated as of Alliant Energy Corporation, effective March 13, 2018April 1, 2019, creating IPL’s 3.60% Senior Debentures due April 1, 2029 (incorporated by reference to Exhibit 3.14.1 to Alliant Energy’s Form 8-K, filed March 15, 2018 (File No. 1-9894))
10.1
Term Loan Credit Agreement, dated as of April 26, 2018, among AEF, Alliant Energy, U.S. Bank National Association and the lender parties set forth therein (incorporated by reference to Exhibit 10.1 to Alliant Energy’sIPL’s Form 8-K, filed April 30, 20181, 2019 (File No. 1-9894)1-4117))
12.1
Ratio of Earnings to Fixed Charges for Alliant Energy
12.2
Ratio of Earnings to Fixed Charges and Ratio of Earnings to Combined Fixed Charges and Preferred Dividend Requirements for IPL
12.3
Ratio of Earnings to Fixed Charges for WPL
31.1 
Certification of the Chairman and Chief Executive Officer for Alliant Energy
31.2 
Certification of the Senior Vice President and Chief Financial Officer and Treasurer for Alliant Energy
31.3 
Certification of the Chairman and Chief Executive Officer for IPL
31.4 
Certification of the Senior Vice President and Chief Financial Officer and Treasurer for IPL
31.5 
Certification of the Chairman and Chief Executive Officer for WPL
31.6 
Certification of the Senior Vice President and Chief Financial Officer and Treasurer 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 XBRL Instance Document
101.SCH XBRL Taxonomy Extension Schema Document
101.CAL XBRL Taxonomy Extension Calculation Linkbase Document
101.LAB XBRL Taxonomy Extension Label Linkbase Document
101.PRE XBRL Taxonomy Extension Presentation Linkbase Document
101.DEF XBRL Taxonomy Extension Definition Linkbase Document

35
Table of Contents


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 May 2018.2019.
ALLIANT ENERGY CORPORATION 
Registrant 
  
By: /s/ Benjamin M. BilitzChief Accounting Officer and Controller
Benjamin M. Bilitz(Principal Accounting Officer and Authorized Signatory)
INTERSTATE POWER AND LIGHT COMPANY 
Registrant 
  
By: /s/ Benjamin M. BilitzChief Accounting Officer and Controller
Benjamin M. Bilitz(Principal Accounting Officer and Authorized Signatory)
WISCONSIN POWER AND LIGHT COMPANY 
Registrant 
  
By: /s/ Benjamin M. BilitzChief Accounting Officer and Controller
Benjamin M. Bilitz(Principal Accounting Officer and Authorized Signatory)


 3632