Derivative Instruments (Tables)

9 Months Ended

Sep. 30, 2015

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

As of September 30, 2015, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts, FTRs and coal contracts that were accounted for as commodity derivative instruments were as follows (units in thousands):

	Electricity		FTRs		Natural Gas		Coal
	MWhs	Years	MWhs	Years	Dths	Years	Tons	Years
Alliant Energy	7,024	2015-2018	15,793	2015-2016	103,867	2015-2020	4,918	2015-2018
IPL	1,302	2015-2016	8,880	2015-2016	67,910	2015-2020	1,585	2015-2018
WPL	5,722	2015-2018	6,913	2015-2016	35,957	2015-2017	3,333	2015-2018

Fair Value Of Financial Instruments

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
Commodity contracts	September 30, 2015		December 31, 2014		September 30, 2015		December 31, 2014		September 30, 2015		December 31, 2014
Current derivative assets		$19.5		$30.5		$17.8		$27.4		$1.7		$3.1
Non-current derivative assets	0.8		8.1		0.7		0.6		0.1		7.5
Current derivative liabilities	35.4		28.1		15.2		16.4		20.2		11.7
Non-current derivative liabilities	23.7		9.5		6.8		3.1		16.9		6.4

Gains And Losses From Derivative Instruments

Changes in gains (losses) from commodity derivative instruments were recorded with offsets to regulatory assets or regulatory liabilities on the balance sheets as follows (in millions):

	Alliant Energy						IPL						WPL
	2015			2014			2015			2014			2015			2014
Three Months Ended September 30
Regulatory assets		($27.4	)		$8.3			($9.5	)		$7.3			($17.9	)		$1.0
Regulatory liabilities	(2.5		)	(6.2		)	(1.2		)	(2.0		)	(1.3		)	(4.2		)
Nine Months Ended September 30
Regulatory assets	(69.5		)	13.8			(33.3		)	8.7			(36.2		)	5.1
Regulatory liabilities	(4.9		)	63.2			1.0			13.9			(5.9		)	49.3

Credit Risk-related Contingent Features

The aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position, as well as 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, were as follows (in millions):

	Alliant Energy				IPL				WPL
	September 30, 2015		December 31, 2014		September 30, 2015		December 31, 2014		September 30, 2015		December 31, 2014
Aggregate fair value		$59.1		$37.6		$22.0		$19.5		$37.1		$18.1
Credit support to be posted if triggered	59.0		37.4		22.0		19.5		37.0		17.9

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, derivative assets and derivative liabilities related to commodity contracts would have been presented on the balance sheets as follows (in millions):

	Alliant Energy				IPL				WPL
	Gross				Gross				Gross
	(as reported)		Net		(as reported)		Net		(as reported)		Net
September 30, 2015
Derivative assets		$20.3		$18.0		$18.5		$17.3		$1.8		$0.7
Derivative liabilities	59.1		56.8		22.0		20.8		37.1		36.0
December 31, 2014
Derivative assets	38.6		33.0		28.0		24.7		10.6		8.3
Derivative liabilities	37.6		32.0		19.5		16.2		18.1		15.8

IPL [Member]

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

As of September 30, 2015, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts, FTRs and coal contracts that were accounted for as commodity derivative instruments were as follows (units in thousands):

	Electricity		FTRs		Natural Gas		Coal
	MWhs	Years	MWhs	Years	Dths	Years	Tons	Years
Alliant Energy	7,024	2015-2018	15,793	2015-2016	103,867	2015-2020	4,918	2015-2018
IPL	1,302	2015-2016	8,880	2015-2016	67,910	2015-2020	1,585	2015-2018
WPL	5,722	2015-2018	6,913	2015-2016	35,957	2015-2017	3,333	2015-2018

Fair Value Of Financial Instruments

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
Commodity contracts	September 30, 2015		December 31, 2014		September 30, 2015		December 31, 2014		September 30, 2015		December 31, 2014
Current derivative assets		$19.5		$30.5		$17.8		$27.4		$1.7		$3.1
Non-current derivative assets	0.8		8.1		0.7		0.6		0.1		7.5
Current derivative liabilities	35.4		28.1		15.2		16.4		20.2		11.7
Non-current derivative liabilities	23.7		9.5		6.8		3.1		16.9		6.4

Gains And Losses From Derivative Instruments

Changes in gains (losses) from commodity derivative instruments were recorded with offsets to regulatory assets or regulatory liabilities on the balance sheets as follows (in millions):

	Alliant Energy						IPL						WPL
	2015			2014			2015			2014			2015			2014
Three Months Ended September 30
Regulatory assets		($27.4	)		$8.3			($9.5	)		$7.3			($17.9	)		$1.0
Regulatory liabilities	(2.5		)	(6.2		)	(1.2		)	(2.0		)	(1.3		)	(4.2		)
Nine Months Ended September 30
Regulatory assets	(69.5		)	13.8			(33.3		)	8.7			(36.2		)	5.1
Regulatory liabilities	(4.9		)	63.2			1.0			13.9			(5.9		)	49.3

Credit Risk-related Contingent Features

The aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position, as well as 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, were as follows (in millions):

	Alliant Energy				IPL				WPL
	September 30, 2015		December 31, 2014		September 30, 2015		December 31, 2014		September 30, 2015		December 31, 2014
Aggregate fair value		$59.1		$37.6		$22.0		$19.5		$37.1		$18.1
Credit support to be posted if triggered	59.0		37.4		22.0		19.5		37.0		17.9

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, derivative assets and derivative liabilities related to commodity contracts would have been presented on the balance sheets as follows (in millions):

	Alliant Energy				IPL				WPL
	Gross				Gross				Gross
	(as reported)		Net		(as reported)		Net		(as reported)		Net
September 30, 2015
Derivative assets		$20.3		$18.0		$18.5		$17.3		$1.8		$0.7
Derivative liabilities	59.1		56.8		22.0		20.8		37.1		36.0
December 31, 2014
Derivative assets	38.6		33.0		28.0		24.7		10.6		8.3
Derivative liabilities	37.6		32.0		19.5		16.2		18.1		15.8

WPL [Member]

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

As of September 30, 2015, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts, FTRs and coal contracts that were accounted for as commodity derivative instruments were as follows (units in thousands):

	Electricity		FTRs		Natural Gas		Coal
	MWhs	Years	MWhs	Years	Dths	Years	Tons	Years
Alliant Energy	7,024	2015-2018	15,793	2015-2016	103,867	2015-2020	4,918	2015-2018
IPL	1,302	2015-2016	8,880	2015-2016	67,910	2015-2020	1,585	2015-2018
WPL	5,722	2015-2018	6,913	2015-2016	35,957	2015-2017	3,333	2015-2018

Fair Value Of Financial Instruments

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
Commodity contracts	September 30, 2015		December 31, 2014		September 30, 2015		December 31, 2014		September 30, 2015		December 31, 2014
Current derivative assets		$19.5		$30.5		$17.8		$27.4		$1.7		$3.1
Non-current derivative assets	0.8		8.1		0.7		0.6		0.1		7.5
Current derivative liabilities	35.4		28.1		15.2		16.4		20.2		11.7
Non-current derivative liabilities	23.7		9.5		6.8		3.1		16.9		6.4

Gains And Losses From Derivative Instruments

Changes in gains (losses) from commodity derivative instruments were recorded with offsets to regulatory assets or regulatory liabilities on the balance sheets as follows (in millions):

	Alliant Energy						IPL						WPL
	2015			2014			2015			2014			2015			2014
Three Months Ended September 30
Regulatory assets		($27.4	)		$8.3			($9.5	)		$7.3			($17.9	)		$1.0
Regulatory liabilities	(2.5		)	(6.2		)	(1.2		)	(2.0		)	(1.3		)	(4.2		)
Nine Months Ended September 30
Regulatory assets	(69.5		)	13.8			(33.3		)	8.7			(36.2		)	5.1
Regulatory liabilities	(4.9		)	63.2			1.0			13.9			(5.9		)	49.3

Credit Risk-related Contingent Features

The aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position, as well as 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, were as follows (in millions):

	Alliant Energy				IPL				WPL
	September 30, 2015		December 31, 2014		September 30, 2015		December 31, 2014		September 30, 2015		December 31, 2014
Aggregate fair value		$59.1		$37.6		$22.0		$19.5		$37.1		$18.1
Credit support to be posted if triggered	59.0		37.4		22.0		19.5		37.0		17.9

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, derivative assets and derivative liabilities related to commodity contracts would have been presented on the balance sheets as follows (in millions):

	Alliant Energy				IPL				WPL
	Gross				Gross				Gross
	(as reported)		Net		(as reported)		Net		(as reported)		Net
September 30, 2015
Derivative assets		$20.3		$18.0		$18.5		$17.3		$1.8		$0.7
Derivative liabilities	59.1		56.8		22.0		20.8		37.1		36.0
December 31, 2014
Derivative assets	38.6		33.0		28.0		24.7		10.6		8.3
Derivative liabilities	37.6		32.0		19.5		16.2		18.1		15.8