Summary Of Significant Accounting Policies

6 Months Ended

Jun. 30, 2012

Summary Of Significant Accounting Policies

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

(a) General - The interim condensed consolidated financial statements included herein have been prepared by Alliant Energy, IPL and WPL, without audit, 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 accounting principles generally accepted in the U.S. (GAAP) have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. Alliant Energy’s condensed consolidated financial statements include the accounts of Alliant Energy and its consolidated subsidiaries (including IPL, WPL, Resources and Alliant Energy Corporate Services, Inc. (Corporate Services)). IPL’s condensed consolidated financial statements include the accounts of IPL and its consolidated subsidiary. WPL’s condensed consolidated financial statements include the accounts of WPL and its consolidated subsidiaries. These financial statements should be read in conjunction with the financial statements and the notes thereto included in Alliant Energy’s, IPL’s and WPL’s 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 condensed consolidated results of operations for the three and six months ended June 30, 2012 and 2011, the condensed consolidated financial position at June 30, 2012 and December 31, 2011, and the condensed consolidated statements of cash flows for the six months ended June 30, 2012 and 2011 have been made. Results for the six months ended June 30, 2012 are not necessarily indicative of results that may be expected for the year ending December 31, 2012. A change in management’s estimates or assumptions could have a material impact on Alliant Energy’s, IPL’s and WPL’s respective financial condition and results of operations during the period in which such change occurred. Certain prior period amounts in the Condensed Consolidated Financial Statements and Notes to Condensed Consolidated Financial Statements have been reclassified to conform to the current period presentation for comparative purposes. Unless otherwise noted, the notes herein have been revised to exclude discontinued operations and assets and liabilities held for sale for all periods presented.

(b) Regulatory Assets and Regulatory Liabilities -

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



	Alliant Energy				IPL				WPL
	June 30, 2012		December 31, 2011		June 30, 2012		December 31, 2011		June 30, 2012		December 31, 2011
Tax-related		$652.8		$634.7		$630.8		$614.6		$22.0		$20.1
Pension and other postretirement benefits costs	502.8		514.1		260.0		264.9		242.8		249.2
Derivatives	64.2		77.7		28.8		33.5		35.4		44.2
Asset retirement obligations	58.0		65.9		39.6		48.7		18.4		17.2
Environmental-related costs	37.1		38.9		32.2		32.2		4.9		6.7
Emission allowances	30.0		30.0		30.0		30.0		—		—
IPL’s electric transmission service costs	20.8		24.9		20.8		24.9		—		—
Debt redemption costs	20.8		21.8		14.3		15.1		6.5		6.7
Proposed base-load projects costs	17.8		21.5		12.7		15.3		5.1		6.2
Other	75.2		65.5		41.2		38.1		34.0		27.4
		$1,479.5		$1,495.0		$1,110.4		$1,117.3		$369.1		$377.7

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



	Alliant Energy				IPL				WPL
	June 30, 2012		December 31, 2011		June 30, 2012		December 31, 2011		June 30, 2012		December 31, 2011
Cost of removal obligations		$406.8		$404.9		$265.0		$261.9		$141.8		$143.0
IPL’s tax benefit rider	309.1		349.6		309.1		349.6		—		—
Energy conservation cost recovery	43.5		29.6		7.8		4.7		35.7		24.9
IPL’s electric transmission assets sale	38.0		45.1		38.0		45.1		—		—
Commodity cost recovery	5.4		23.8		0.5		23.2		4.9		0.6
Other	58.8		57.1		35.5		36.8		23.3		20.3
		$861.6		$910.1		$655.9		$721.3		$205.7		$188.8

Proposed base-load projects costs - The Minnesota Public Utilities Commission’s (MPUC’s) June 2011 oral decision related to IPL’s 2009 test year Minnesota retail electric rate case authorized IPL to recover $2 million of previously incurred plant cancellation costs for its proposed base-load project referred to as Sutherland #4. As a result, Alliant Energy and IPL recorded a $2 million increase to regulatory assets, and a $2 million credit to “Utility - Other operation and maintenance” in their Condensed Consolidated Statements of Income in the second quarter of 2011.

IPL’s tax benefit rider - Alliant Energy’s and IPL’s “IPL’s tax benefit rider” regulatory liabilities in the above table decreased primarily due to $40 million of regulatory liabilities used to credit IPL’s Iowa retail electric customers’ bills during the six months ended June 30, 2012. Refer to Note 2 for discussion of a proposed tax benefit rider for IPL’s Iowa retail gas customers and Note 4 for additional details regarding the tax benefit rider for IPL’s Iowa retail electric customers.

IPL’s electric transmission assets sale - Based on the MPUC’s June 2011 oral decision related to IPL’s 2009 test year Minnesota retail electric rate case, IPL was ordered to refund a higher amount of the gain realized from the sale of its electric transmission assets in 2007 to its Minnesota retail electric customers than originally estimated. As a result, Alliant Energy and IPL recorded a $5 million increase to regulatory liabilities, and a $5 million charge to “Utility - Other operation and maintenance” in their Condensed Consolidated Statements of Income in the second quarter of 2011 based on an estimate of the additional amount that is probable of being refunded.

Other - Based on an assessment completed in the second quarter of 2011, Alliant Energy, IPL and WPL recognized impairment charges of $6 million, $1 million and $5 million, respectively, for regulatory assets that were no longer probable of future recovery. The regulatory asset impairment charges were recorded by Alliant Energy, IPL and WPL as reductions in regulatory assets, and charges to “Utility - Other operation and maintenance” in their Condensed Consolidated Statements of Income in the second quarter of 2011.

Based on the Public Service Commission of Wisconsin’s (PSCW’s) July 2012 order related to WPL’s 2013/2014 test period Wisconsin retail electric and gas rate case, WPL was authorized to recover previously incurred costs associated with the acquisition of a 25% ownership interest in Edgewater Unit 5 and proposed clean air compliance plan projects. As a result, Alliant Energy and WPL recorded a $5 million increase to “Regulatory assets” on their Condensed Consolidated Balance Sheets and a $5 million credit to “Utility - Other operation and maintenance” in their Condensed Consolidated Statements of Income in the second quarter of 2012.

WPL’s Edgewater Unit 5 Emission Controls Project - WPL is currently installing a selective catalytic reduction (SCR) system at Edgewater Unit 5 to reduce nitrogen oxide (NOx) emissions at the generating facility. Construction began in the third quarter of 2010 and is expected to be completed by the end of 2012. The SCR is expected to help meet requirements under the Wisconsin Reasonably Available Control Technology (RACT) Rule, which require additional NOx emission reductions at Edgewater by May 2013. As of June 30, 2012, WPL recorded capitalized expenditures of $98 million and allowance for funds used during construction (AFUDC) of $6 million for the SCR system in “Construction work in progress - Edgewater Generating Station Unit 5 emission controls” on Alliant Energy’s and WPL’s Condensed Consolidated Balance Sheets.

WPL’s Columbia Units 1 and 2 Emission Controls Project - WPL is currently installing scrubbers and baghouses at Columbia Units 1 and 2 to reduce sulfur dioxide (SO2) and mercury emissions at the generating facility. Construction began in the first quarter of 2012 and is expected to be completed in 2014. The scrubbers and baghouses are expected to help meet requirements under the Clean Air Interstate Rule (CAIR), the Cross-State Air Pollution Rule (CSAPR) or some alternative to these rules that may be implemented, the Utility Maximum Achievable Control Technology (MACT) Rule and the Wisconsin State Mercury Rule. As of June 30, 2012, WPL recorded capitalized expenditures of $53 million and AFUDC of $1 million for the scrubbers and baghouses in “Construction work in progress - Columbia Energy Center Units 1 and 2 emission controls” on Alliant Energy’s and WPL’s Condensed Consolidated Balance Sheets.

Franklin County Wind Project - In 2008, Alliant Energy entered into a master supply agreement with Vestas-American Wind Technology, Inc. (Vestas) to purchase 500 MW of wind turbine generator sets and related equipment. Alliant Energy utilized 400 MW of these wind turbine generator sets and related equipment to construct IPL’s Whispering Willow - East and WPL’s Bent Tree - Phase I wind projects. In the second quarter of 2011, Alliant Energy decided to utilize the remaining 100 MW of wind turbine generator sets and related equipment at Resources to build the Franklin County wind project. In the second quarter of 2011, IPL sold the assets for this wind project to Resources for $115.3 million, which represented IPL’s book value for progress payments to date for the 100 MW of wind turbine generator sets and related equipment and land rights in Franklin County, Iowa. In addition, Resources assumed the remaining progress payments to Vestas for the 100 MW of wind turbine generator sets and related equipment. The proceeds received by IPL were recorded in investing activities in IPL’s Condensed Consolidated Statement of Cash Flows in the second quarter of 2011. Refer to Note 1(d) for further discussion of the Franklin County wind project.

IPL’s Whispering Willow - East Wind Project - In 2011, IPL received an order from the MPUC approving a temporary recovery rate for the Minnesota retail portion of its Whispering Willow - East wind project construction costs. In its order, the MPUC did not conclude on the prudence of these project costs. The prudence of these project costs and the final recovery rate for these costs will be addressed in a separate proceeding that is expected to be completed in 2013. The initial recovery rate approved by the MPUC is below the amount required by IPL to recover the Minnesota retail portion of its total project costs. Based on its interpretation of the order, IPL currently believes that it is probable it will not be allowed to recover the entire Minnesota retail portion of its project costs. IPL currently believes the most likely outcome of the final rate proceeding will result in the MPUC effectively disallowing recovery of approximately $8 million of project costs out of a total of approximately $30 million of project costs allocated to the Minnesota retail jurisdiction. As a result, IPL recognized an $8 million impairment related to this probable disallowance, which was recorded as a reduction to electric plant in service and a charge to “Utility - Other operation and maintenance” in Alliant Energy’s and IPL’s Condensed Consolidated Statements of Income in the second quarter of 2011. This amount is subject to change until the MPUC determines the final recovery rate for these project costs.

Wind Site in Green Lake and Fond du Lac Counties in Wisconsin - In 2009, WPL purchased development rights to an approximate 100 MW wind site in Green Lake and Fond du Lac Counties in Wisconsin. Due to events in the first quarter of 2011 resulting in uncertainty regarding wind siting requirements in Wisconsin and increased risks with permitting this wind site, WPL determined it would be difficult to sell or effectively use the site for wind development. As a result, WPL recognized a $5 million impairment in the first quarter of 2011 for the amount of capitalized costs incurred for this site. The impairment was recorded as a reduction in other utility property, plant and equipment, and a charge to “Utility - Other operation and maintenance” in Alliant Energy’s and WPL’s Condensed Consolidated Statements of Income in the first half of 2011.

Depreciation - In May 2012, the PSCW issued an order approving the implementation of updated depreciation rates for WPL as a result of a recently completed depreciation study. The updated depreciation rates will be effective January 1, 2013 for all assets other than Riverside. WPL’s depreciation rates for Riverside will be effective on the purchase date of Riverside. WPL estimates the new average rates of depreciation for its electric generation, electric distribution and gas properties will be approximately 3.6%, 2.7% and 2.5%, respectively, during 2013.

(d) Non-regulated and Other Property, Plant and Equipment - As of June 30, 2012, Alliant Energy recorded capitalized expenditures of $183 million and capitalized interest of $6 million in “Non-regulated Generation property, plant and equipment” on Alliant Energy’s Condensed Consolidated Balance Sheet related to Resources’ Franklin County wind project. Refer to Note 1(c) for further discussion of the Franklin County wind project.

In April 2012, Alliant Energy exercised its option under the corporate headquarters lease and purchased the building at the expiration of the lease term for $48 million.

(e) Comprehensive Income (Loss) - For the three and six months ended June 30, 2012 and 2011, Alliant Energy’s other comprehensive income was not material; therefore, its comprehensive income was substantially equal to its net income for such periods. For the three and six months ended June 30, 2012 and 2011, IPL and WPL had no other comprehensive income; therefore their comprehensive income (loss) was equal to their earnings available (loss) for common stock for such periods.

(f) Cash Flows Presentation - Alliant Energy reports cash flows from continuing operations together with cash flows from discontinued operations in its Condensed Consolidated Statements of Cash Flows. Refer to Note 13 for details of cash flows from discontinued operations.

IPL [Member]

Summary Of Significant Accounting Policies

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

(b) Regulatory Assets and Regulatory Liabilities -

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



	Alliant Energy				IPL				WPL
	June 30, 2012		December 31, 2011		June 30, 2012		December 31, 2011		June 30, 2012		December 31, 2011
Tax-related		$652.8		$634.7		$630.8		$614.6		$22.0		$20.1
Pension and other postretirement benefits costs	502.8		514.1		260.0		264.9		242.8		249.2
Derivatives	64.2		77.7		28.8		33.5		35.4		44.2
Asset retirement obligations	58.0		65.9		39.6		48.7		18.4		17.2
Environmental-related costs	37.1		38.9		32.2		32.2		4.9		6.7
Emission allowances	30.0		30.0		30.0		30.0		—		—
IPL’s electric transmission service costs	20.8		24.9		20.8		24.9		—		—
Debt redemption costs	20.8		21.8		14.3		15.1		6.5		6.7
Proposed base-load projects costs	17.8		21.5		12.7		15.3		5.1		6.2
Other	75.2		65.5		41.2		38.1		34.0		27.4
		$1,479.5		$1,495.0		$1,110.4		$1,117.3		$369.1		$377.7

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



	Alliant Energy				IPL				WPL
	June 30, 2012		December 31, 2011		June 30, 2012		December 31, 2011		June 30, 2012		December 31, 2011
Cost of removal obligations		$406.8		$404.9		$265.0		$261.9		$141.8		$143.0
IPL’s tax benefit rider	309.1		349.6		309.1		349.6		—		—
Energy conservation cost recovery	43.5		29.6		7.8		4.7		35.7		24.9
IPL’s electric transmission assets sale	38.0		45.1		38.0		45.1		—		—
Commodity cost recovery	5.4		23.8		0.5		23.2		4.9		0.6
Other	58.8		57.1		35.5		36.8		23.3		20.3
		$861.6		$910.1		$655.9		$721.3		$205.7		$188.8

In April 2012, Alliant Energy exercised its option under the corporate headquarters lease and purchased the building at the expiration of the lease term for $48 million.

WPL [Member]

Summary Of Significant Accounting Policies

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

(b) Regulatory Assets and Regulatory Liabilities -

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



	Alliant Energy				IPL				WPL
	June 30, 2012		December 31, 2011		June 30, 2012		December 31, 2011		June 30, 2012		December 31, 2011
Tax-related		$652.8		$634.7		$630.8		$614.6		$22.0		$20.1
Pension and other postretirement benefits costs	502.8		514.1		260.0		264.9		242.8		249.2
Derivatives	64.2		77.7		28.8		33.5		35.4		44.2
Asset retirement obligations	58.0		65.9		39.6		48.7		18.4		17.2
Environmental-related costs	37.1		38.9		32.2		32.2		4.9		6.7
Emission allowances	30.0		30.0		30.0		30.0		—		—
IPL’s electric transmission service costs	20.8		24.9		20.8		24.9		—		—
Debt redemption costs	20.8		21.8		14.3		15.1		6.5		6.7
Proposed base-load projects costs	17.8		21.5		12.7		15.3		5.1		6.2
Other	75.2		65.5		41.2		38.1		34.0		27.4
		$1,479.5		$1,495.0		$1,110.4		$1,117.3		$369.1		$377.7

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



	Alliant Energy				IPL				WPL
	June 30, 2012		December 31, 2011		June 30, 2012		December 31, 2011		June 30, 2012		December 31, 2011
Cost of removal obligations		$406.8		$404.9		$265.0		$261.9		$141.8		$143.0
IPL’s tax benefit rider	309.1		349.6		309.1		349.6		—		—
Energy conservation cost recovery	43.5		29.6		7.8		4.7		35.7		24.9
IPL’s electric transmission assets sale	38.0		45.1		38.0		45.1		—		—
Commodity cost recovery	5.4		23.8		0.5		23.2		4.9		0.6
Other	58.8		57.1		35.5		36.8		23.3		20.3
		$861.6		$910.1		$655.9		$721.3		$205.7		$188.8

In April 2012, Alliant Energy exercised its option under the corporate headquarters lease and purchased the building at the expiration of the lease term for $48 million.

- Definition

The entire disclosure for all significant accounting policies of the reporting entity.

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