Regulatory Matters

6 Months Ended

Jun. 30, 2014

Regulatory Matters [Line Items]

Regulatory Matters

REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

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

	Alliant Energy				IPL				WPL
	June 30, 2014		December 31, 2013		June 30, 2014		December 31, 2013		June 30, 2014		December 31, 2013
Tax-related		$870.7		$829.7		$844.1		$798.6		$26.6		$31.1
Pension and OPEB costs	348.4		355.3		171.2		174.2		177.2		181.1
AROs	71.6		65.7		40.9		36.7		30.7		29.0
Emission allowances	28.7		30.0		28.7		30.0		—		—
Environmental-related costs	27.2		25.0		22.5		21.0		4.7		4.0
Derivatives	12.5		21.1		6.1		5.9		6.4		15.2
Other	94.1		86.4		39.1		47.1		55.0		39.3
		$1,453.2		$1,413.2		$1,152.6		$1,113.5		$300.6		$299.7

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

	Alliant Energy				IPL				WPL
	June 30, 2014		December 31, 2013		June 30, 2014		December 31, 2013		June 30, 2014		December 31, 2013
Cost of removal obligations		$422.3		$418.9		$280.9		$277.7		$141.4		$141.2
IPL’s tax benefit riders	243.3		265.4		243.3		265.4		—		—
Energy efficiency cost recovery	67.1		52.7		13.5		9.3		53.6		43.4
Derivatives	48.2		7.2		9.7		3.6		38.5		3.6
IPL’s electric transmission cost recovery	20.8		14.6		20.8		14.6		—		—
IPL’s electric transmission assets sale	16.1		21.6		16.1		21.6		—		—
Other	45.7		41.1		24.3		22.7		21.4		18.4
		$863.5		$821.5		$608.6		$614.9		$254.9		$206.6

Tax-related- 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 six months ended June 30, 2014, Alliant Energy’s and IPL’s tax-related regulatory assets increased primarily due to property-related differences for qualifying repair expenditures and a tax accounting method change in the second quarter of 2014 for cost of removal expenditures at IPL. The increase related to the tax accounting method change was offset by increased regulatory liabilities as discussed below in “IPL’s tax benefit riders.”

Derivatives - Refer to Note 13 for discussion of derivative assets and derivative liabilities.

IPL’s tax benefit riders - IPL’s tax benefit riders utilize regulatory liabilities to credit bills of IPL’s Iowa retail electric and gas customers to help offset the impact of rate increases on such customers. These regulatory liabilities are related to tax benefits from tax accounting method changes for repairs expenditures, allocation of mixed service costs and allocation of insurance proceeds from floods in 2008. For the six months ended June 30, 2014, Alliant Energy and IPL utilized “IPL’s tax benefit riders” regulatory liabilities to credit IPL’s Iowa retail electric and gas customers’ bills as follows (in millions):

Electric tax benefit rider		$42
Gas tax benefit rider	6
		$48

In 2013, the U.S. Department of the Treasury issued tangible property regulations clarifying the tax treatment of costs incurred to acquire, maintain or improve tangible property and to retire and remove depreciable property. The regulations clarified the ability to deduct cost of removal expenditures on partial dispositions of assets. In 2014, the Internal Revenue Service issued implementation guidance related to these tangible property regulations, which allowed companies to file a tax method of accounting change to deduct cost of removal expenditures on partial dispositions that were previously capitalized. During the second quarter of 2014, Alliant Energy, IPL and WPL implemented this tax accounting method change, which will result in the inclusion of additional tax deductions on Alliant Energy’s U.S. federal income tax return for the calendar year 2014. IPL currently anticipates refunding these tax benefits to its Iowa retail electric and gas customers in the future, and as a result, Alliant Energy and IPL recorded an increase of $26 million to IPL’s tax benefit riders regulatory liabilities in the second quarter of 2014.

Refer to Note 9 for additional details regarding the tax benefit riders.

Utility Rate Cases -

WPL’s Wisconsin Retail Electric and Gas Rate Case (2015/2016 Test Period) - In July 2014, WPL received an order from the PSCW authorizing WPL to implement its retail base rate filing as requested. The retail base rate filing request was based on a forward-looking test period that included 2015 and 2016. The filing requested authority to maintain customer base rates for WPL’s retail electric customers at their current levels through the end of 2016. The filing also requested approval for WPL to implement a $5 million decrease in annual base rates for WPL’s retail gas customers effective January 1, 2015 followed by a freeze of such gas base rates through the end of 2016.

IPL’s Iowa Retail Electric Rate Case (2013 Test Year) - In March 2014, after reaching a unanimous agreement with parties to the DAEC PPA proceeding, IPL filed with the IUB a settlement agreement and joint motion for approval of the settlement agreement to extend IPL’s Iowa retail electric base rate freeze through 2016 and provide retail electric customer billing credits of $70 million in 2014 (beginning May 2014), decreasing to $25 million in 2015 and further decreasing to $10 million in 2016. During the three and six months ended June 30, 2014, IPL recorded $20 million of such billing credits to reduce retail electric customers’ bills. IPL currently expects a decision from the IUB regarding the settlement agreement in the third quarter of 2014.

IPL’s Iowa Retail Electric Rate Case (2009 Test Year) -

Electric Tax Benefit Rider - In 2013, the IUB authorized IPL to reduce the electric tax benefit rider billing credits on customers’ bills by $24 million in 2013 and $15 million in 2014 to recognize the revenue requirement impact of the changes in tax accounting methods. For the three and six months ended June 30, the revenue requirement adjustment recognized by both Alliant Energy and IPL is included in the table below (in millions). The revenue requirement adjustment resulted in increases to electric revenues in their income statements and was recognized through the energy adjustment clause as a reduction of the credits on IPL’s Iowa retail electric customers’ bills from the electric tax benefit rider.

	Three Months				Six Months
	2014		2013		2014		2013
Revenue requirement adjustment		$3		$5		$7		$11

WPL’s Retail Fuel-related Rate Filing (2015 Test Year) - In June 2014, WPL filed a request with the PSCW to increase annual rates for WPL’s retail electric customers by $55 million, or approximately 5%, in 2015. The increase includes $41 million of anticipated increases in retail electric fuel-related costs in 2015 and $14 million to recover a portion of the under-collection of fuel-related costs projected for 2014. Any rate changes granted from this request are expected to be effective on January 1, 2015. WPL currently expects a decision from the PSCW regarding this rate filing by the end of 2014.

WPL’s Retail Fuel-related Rate Filing (2014 Test Year) - In December 2013, WPL received an order from the PSCW authorizing an annual retail electric rate increase of $19 million, or approximately 2%, effective January 1, 2014 to reflect anticipated increases in retail fuel-related costs in 2014 compared to the fuel-related cost estimates used to determine rates for 2013. WPL’s 2014 fuel-related costs will be subject to deferral if they fall outside an annual bandwidth of plus or minus 2% of the approved annual forecasted fuel-related costs. Retail fuel-related costs incurred by WPL through June 30, 2014 were higher than fuel-related costs used to determine rates for such period resulting in an under-collection of fuel-related costs during the six months ended June 30, 2014. As of June 30, 2014, Alliant Energy and WPL recorded $17 million in “Regulatory assets” on their balance sheets for fuel-related costs incurred during the six months ended June 30, 2014 that are expected to fall outside the approved bandwidth of plus or minus 2% for 2014. The $17 million of deferred fuel-related costs is included in “Other” in Alliant Energy’s and WPL’s regulatory assets tables above.

IPL [Member]

Regulatory Matters [Line Items]

Regulatory Matters

REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

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

	Alliant Energy				IPL				WPL
	June 30, 2014		December 31, 2013		June 30, 2014		December 31, 2013		June 30, 2014		December 31, 2013
Tax-related		$870.7		$829.7		$844.1		$798.6		$26.6		$31.1
Pension and OPEB costs	348.4		355.3		171.2		174.2		177.2		181.1
AROs	71.6		65.7		40.9		36.7		30.7		29.0
Emission allowances	28.7		30.0		28.7		30.0		—		—
Environmental-related costs	27.2		25.0		22.5		21.0		4.7		4.0
Derivatives	12.5		21.1		6.1		5.9		6.4		15.2
Other	94.1		86.4		39.1		47.1		55.0		39.3
		$1,453.2		$1,413.2		$1,152.6		$1,113.5		$300.6		$299.7

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

	Alliant Energy				IPL				WPL
	June 30, 2014		December 31, 2013		June 30, 2014		December 31, 2013		June 30, 2014		December 31, 2013
Cost of removal obligations		$422.3		$418.9		$280.9		$277.7		$141.4		$141.2
IPL’s tax benefit riders	243.3		265.4		243.3		265.4		—		—
Energy efficiency cost recovery	67.1		52.7		13.5		9.3		53.6		43.4
Derivatives	48.2		7.2		9.7		3.6		38.5		3.6
IPL’s electric transmission cost recovery	20.8		14.6		20.8		14.6		—		—
IPL’s electric transmission assets sale	16.1		21.6		16.1		21.6		—		—
Other	45.7		41.1		24.3		22.7		21.4		18.4
		$863.5		$821.5		$608.6		$614.9		$254.9		$206.6

Tax-related- 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 six months ended June 30, 2014, Alliant Energy’s and IPL’s tax-related regulatory assets increased primarily due to property-related differences for qualifying repair expenditures and a tax accounting method change in the second quarter of 2014 for cost of removal expenditures at IPL. The increase related to the tax accounting method change was offset by increased regulatory liabilities as discussed below in “IPL’s tax benefit riders.”

Derivatives - Refer to Note 13 for discussion of derivative assets and derivative liabilities.

IPL’s tax benefit riders - IPL’s tax benefit riders utilize regulatory liabilities to credit bills of IPL’s Iowa retail electric and gas customers to help offset the impact of rate increases on such customers. These regulatory liabilities are related to tax benefits from tax accounting method changes for repairs expenditures, allocation of mixed service costs and allocation of insurance proceeds from floods in 2008. For the six months ended June 30, 2014, Alliant Energy and IPL utilized “IPL’s tax benefit riders” regulatory liabilities to credit IPL’s Iowa retail electric and gas customers’ bills as follows (in millions):

Electric tax benefit rider		$42
Gas tax benefit rider	6
		$48

In 2013, the U.S. Department of the Treasury issued tangible property regulations clarifying the tax treatment of costs incurred to acquire, maintain or improve tangible property and to retire and remove depreciable property. The regulations clarified the ability to deduct cost of removal expenditures on partial dispositions of assets. In 2014, the Internal Revenue Service issued implementation guidance related to these tangible property regulations, which allowed companies to file a tax method of accounting change to deduct cost of removal expenditures on partial dispositions that were previously capitalized. During the second quarter of 2014, Alliant Energy, IPL and WPL implemented this tax accounting method change, which will result in the inclusion of additional tax deductions on Alliant Energy’s U.S. federal income tax return for the calendar year 2014. IPL currently anticipates refunding these tax benefits to its Iowa retail electric and gas customers in the future, and as a result, Alliant Energy and IPL recorded an increase of $26 million to IPL’s tax benefit riders regulatory liabilities in the second quarter of 2014.

Refer to Note 9 for additional details regarding the tax benefit riders.

Utility Rate Cases -

WPL’s Wisconsin Retail Electric and Gas Rate Case (2015/2016 Test Period) - In July 2014, WPL received an order from the PSCW authorizing WPL to implement its retail base rate filing as requested. The retail base rate filing request was based on a forward-looking test period that included 2015 and 2016. The filing requested authority to maintain customer base rates for WPL’s retail electric customers at their current levels through the end of 2016. The filing also requested approval for WPL to implement a $5 million decrease in annual base rates for WPL’s retail gas customers effective January 1, 2015 followed by a freeze of such gas base rates through the end of 2016.

IPL’s Iowa Retail Electric Rate Case (2013 Test Year) - In March 2014, after reaching a unanimous agreement with parties to the DAEC PPA proceeding, IPL filed with the IUB a settlement agreement and joint motion for approval of the settlement agreement to extend IPL’s Iowa retail electric base rate freeze through 2016 and provide retail electric customer billing credits of $70 million in 2014 (beginning May 2014), decreasing to $25 million in 2015 and further decreasing to $10 million in 2016. During the three and six months ended June 30, 2014, IPL recorded $20 million of such billing credits to reduce retail electric customers’ bills. IPL currently expects a decision from the IUB regarding the settlement agreement in the third quarter of 2014.

IPL’s Iowa Retail Electric Rate Case (2009 Test Year) -

Electric Tax Benefit Rider - In 2013, the IUB authorized IPL to reduce the electric tax benefit rider billing credits on customers’ bills by $24 million in 2013 and $15 million in 2014 to recognize the revenue requirement impact of the changes in tax accounting methods. For the three and six months ended June 30, the revenue requirement adjustment recognized by both Alliant Energy and IPL is included in the table below (in millions). The revenue requirement adjustment resulted in increases to electric revenues in their income statements and was recognized through the energy adjustment clause as a reduction of the credits on IPL’s Iowa retail electric customers’ bills from the electric tax benefit rider.

	Three Months				Six Months
	2014		2013		2014		2013
Revenue requirement adjustment		$3		$5		$7		$11

WPL’s Retail Fuel-related Rate Filing (2015 Test Year) - In June 2014, WPL filed a request with the PSCW to increase annual rates for WPL’s retail electric customers by $55 million, or approximately 5%, in 2015. The increase includes $41 million of anticipated increases in retail electric fuel-related costs in 2015 and $14 million to recover a portion of the under-collection of fuel-related costs projected for 2014. Any rate changes granted from this request are expected to be effective on January 1, 2015. WPL currently expects a decision from the PSCW regarding this rate filing by the end of 2014.

WPL’s Retail Fuel-related Rate Filing (2014 Test Year) - In December 2013, WPL received an order from the PSCW authorizing an annual retail electric rate increase of $19 million, or approximately 2%, effective January 1, 2014 to reflect anticipated increases in retail fuel-related costs in 2014 compared to the fuel-related cost estimates used to determine rates for 2013. WPL’s 2014 fuel-related costs will be subject to deferral if they fall outside an annual bandwidth of plus or minus 2% of the approved annual forecasted fuel-related costs. Retail fuel-related costs incurred by WPL through June 30, 2014 were higher than fuel-related costs used to determine rates for such period resulting in an under-collection of fuel-related costs during the six months ended June 30, 2014. As of June 30, 2014, Alliant Energy and WPL recorded $17 million in “Regulatory assets” on their balance sheets for fuel-related costs incurred during the six months ended June 30, 2014 that are expected to fall outside the approved bandwidth of plus or minus 2% for 2014. The $17 million of deferred fuel-related costs is included in “Other” in Alliant Energy’s and WPL’s regulatory assets tables above.

WPL [Member]

Regulatory Matters [Line Items]

Regulatory Matters

REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

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

	Alliant Energy				IPL				WPL
	June 30, 2014		December 31, 2013		June 30, 2014		December 31, 2013		June 30, 2014		December 31, 2013
Tax-related		$870.7		$829.7		$844.1		$798.6		$26.6		$31.1
Pension and OPEB costs	348.4		355.3		171.2		174.2		177.2		181.1
AROs	71.6		65.7		40.9		36.7		30.7		29.0
Emission allowances	28.7		30.0		28.7		30.0		—		—
Environmental-related costs	27.2		25.0		22.5		21.0		4.7		4.0
Derivatives	12.5		21.1		6.1		5.9		6.4		15.2
Other	94.1		86.4		39.1		47.1		55.0		39.3
		$1,453.2		$1,413.2		$1,152.6		$1,113.5		$300.6		$299.7

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

	Alliant Energy				IPL				WPL
	June 30, 2014		December 31, 2013		June 30, 2014		December 31, 2013		June 30, 2014		December 31, 2013
Cost of removal obligations		$422.3		$418.9		$280.9		$277.7		$141.4		$141.2
IPL’s tax benefit riders	243.3		265.4		243.3		265.4		—		—
Energy efficiency cost recovery	67.1		52.7		13.5		9.3		53.6		43.4
Derivatives	48.2		7.2		9.7		3.6		38.5		3.6
IPL’s electric transmission cost recovery	20.8		14.6		20.8		14.6		—		—
IPL’s electric transmission assets sale	16.1		21.6		16.1		21.6		—		—
Other	45.7		41.1		24.3		22.7		21.4		18.4
		$863.5		$821.5		$608.6		$614.9		$254.9		$206.6

Tax-related- 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 six months ended June 30, 2014, Alliant Energy’s and IPL’s tax-related regulatory assets increased primarily due to property-related differences for qualifying repair expenditures and a tax accounting method change in the second quarter of 2014 for cost of removal expenditures at IPL. The increase related to the tax accounting method change was offset by increased regulatory liabilities as discussed below in “IPL’s tax benefit riders.”

Derivatives - Refer to Note 13 for discussion of derivative assets and derivative liabilities.

IPL’s tax benefit riders - IPL’s tax benefit riders utilize regulatory liabilities to credit bills of IPL’s Iowa retail electric and gas customers to help offset the impact of rate increases on such customers. These regulatory liabilities are related to tax benefits from tax accounting method changes for repairs expenditures, allocation of mixed service costs and allocation of insurance proceeds from floods in 2008. For the six months ended June 30, 2014, Alliant Energy and IPL utilized “IPL’s tax benefit riders” regulatory liabilities to credit IPL’s Iowa retail electric and gas customers’ bills as follows (in millions):

Electric tax benefit rider		$42
Gas tax benefit rider	6
		$48

In 2013, the U.S. Department of the Treasury issued tangible property regulations clarifying the tax treatment of costs incurred to acquire, maintain or improve tangible property and to retire and remove depreciable property. The regulations clarified the ability to deduct cost of removal expenditures on partial dispositions of assets. In 2014, the Internal Revenue Service issued implementation guidance related to these tangible property regulations, which allowed companies to file a tax method of accounting change to deduct cost of removal expenditures on partial dispositions that were previously capitalized. During the second quarter of 2014, Alliant Energy, IPL and WPL implemented this tax accounting method change, which will result in the inclusion of additional tax deductions on Alliant Energy’s U.S. federal income tax return for the calendar year 2014. IPL currently anticipates refunding these tax benefits to its Iowa retail electric and gas customers in the future, and as a result, Alliant Energy and IPL recorded an increase of $26 million to IPL’s tax benefit riders regulatory liabilities in the second quarter of 2014.

Refer to Note 9 for additional details regarding the tax benefit riders.

Utility Rate Cases -

WPL’s Wisconsin Retail Electric and Gas Rate Case (2015/2016 Test Period) - In July 2014, WPL received an order from the PSCW authorizing WPL to implement its retail base rate filing as requested. The retail base rate filing request was based on a forward-looking test period that included 2015 and 2016. The filing requested authority to maintain customer base rates for WPL’s retail electric customers at their current levels through the end of 2016. The filing also requested approval for WPL to implement a $5 million decrease in annual base rates for WPL’s retail gas customers effective January 1, 2015 followed by a freeze of such gas base rates through the end of 2016.

IPL’s Iowa Retail Electric Rate Case (2013 Test Year) - In March 2014, after reaching a unanimous agreement with parties to the DAEC PPA proceeding, IPL filed with the IUB a settlement agreement and joint motion for approval of the settlement agreement to extend IPL’s Iowa retail electric base rate freeze through 2016 and provide retail electric customer billing credits of $70 million in 2014 (beginning May 2014), decreasing to $25 million in 2015 and further decreasing to $10 million in 2016. During the three and six months ended June 30, 2014, IPL recorded $20 million of such billing credits to reduce retail electric customers’ bills. IPL currently expects a decision from the IUB regarding the settlement agreement in the third quarter of 2014.

IPL’s Iowa Retail Electric Rate Case (2009 Test Year) -

Electric Tax Benefit Rider - In 2013, the IUB authorized IPL to reduce the electric tax benefit rider billing credits on customers’ bills by $24 million in 2013 and $15 million in 2014 to recognize the revenue requirement impact of the changes in tax accounting methods. For the three and six months ended June 30, the revenue requirement adjustment recognized by both Alliant Energy and IPL is included in the table below (in millions). The revenue requirement adjustment resulted in increases to electric revenues in their income statements and was recognized through the energy adjustment clause as a reduction of the credits on IPL’s Iowa retail electric customers’ bills from the electric tax benefit rider.

	Three Months				Six Months
	2014		2013		2014		2013
Revenue requirement adjustment		$3		$5		$7		$11

WPL’s Retail Fuel-related Rate Filing (2015 Test Year) - In June 2014, WPL filed a request with the PSCW to increase annual rates for WPL’s retail electric customers by $55 million, or approximately 5%, in 2015. The increase includes $41 million of anticipated increases in retail electric fuel-related costs in 2015 and $14 million to recover a portion of the under-collection of fuel-related costs projected for 2014. Any rate changes granted from this request are expected to be effective on January 1, 2015. WPL currently expects a decision from the PSCW regarding this rate filing by the end of 2014.

WPL’s Retail Fuel-related Rate Filing (2014 Test Year) - In December 2013, WPL received an order from the PSCW authorizing an annual retail electric rate increase of $19 million, or approximately 2%, effective January 1, 2014 to reflect anticipated increases in retail fuel-related costs in 2014 compared to the fuel-related cost estimates used to determine rates for 2013. WPL’s 2014 fuel-related costs will be subject to deferral if they fall outside an annual bandwidth of plus or minus 2% of the approved annual forecasted fuel-related costs. Retail fuel-related costs incurred by WPL through June 30, 2014 were higher than fuel-related costs used to determine rates for such period resulting in an under-collection of fuel-related costs during the six months ended June 30, 2014. As of June 30, 2014, Alliant Energy and WPL recorded $17 million in “Regulatory assets” on their balance sheets for fuel-related costs incurred during the six months ended June 30, 2014 that are expected to fall outside the approved bandwidth of plus or minus 2% for 2014. The $17 million of deferred fuel-related costs is included in “Other” in Alliant Energy’s and WPL’s regulatory assets tables above.