XML 74 R24.htm IDEA: XBRL DOCUMENT v2.4.0.8

Regulatory Matters (Tables)

6 Months Ended

Jun. 30, 2014

Regulatory Assets [Line Items]

Regulatory Assets

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

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 Benefit Riders

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

Revenue Requirement Adjustment

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

IPL [Member]

Regulatory Assets [Line Items]

Regulatory Assets

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

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 Benefit Riders

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

Revenue Requirement Adjustment

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 [Member]

Regulatory Assets [Line Items]

Regulatory Assets

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

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

X

- Definition

[Table Text Block] for Revenue Requirement Adjustment [Table]

+ References

No definition available.

+ Details

Name:	lnt_RevenueRequirementAdjustmentTableTextBlock
Namespace Prefix:	lnt_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tax Benefit Rider [Table Text Block]

+ References

No definition available.

+ Details

Name:	lnt_TaxBenefitRiderTableTextBlock
Namespace Prefix:	lnt_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_RegulatoryAssetLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of assets that are created when regulatory agencies permit public utilities to defer certain costs included in rate-setting to the balance sheet.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 980

-SubTopic 340

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 980

-SubTopic 715

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6501251&loc=d3e52485-110419



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 980

-SubTopic 340

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44264-110382

+ Details

Name:	us-gaap_ScheduleOfRegulatoryAssetsTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of regulatory liabilities. Detailed information about liabilities that result from rate actions of a regulator. Rate actions of a regulator can impose a liability on a regulated enterprise resulting in a regulatory liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 980

-SubTopic 405

-Section 25

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6500807&loc=d3e48068-110394

+ Details

Name:	us-gaap_ScheduleOfRegulatoryLiabilitiesTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration