Derivative Instruments (Tables)

12 Months Ended

Dec. 31, 2014

Derivative [Line Items]

Notional Amounts of Derivative Instruments

As of December 31, 2014, gross notional amounts by delivery year 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):

	2015	2016	2017	2018	Total
Alliant Energy
Electricity (MWhs)	4,067	1,553	1,314	1,314	8,248
FTRs (MWhs)	9,505	—	—	—	9,505
Natural gas (Dths)	56,250	20,225	1,829	—	78,304
Coal (tons)	1,490	1,899	1,073	1,113	5,575
IPL
Electricity (MWhs)	1,765	—	—	—	1,765
FTRs (MWhs)	5,503	—	—	—	5,503
Natural gas (Dths)	39,727	10,178	1,014	—	50,919
Coal (tons)	75	830	274	387	1,566
WPL
Electricity (MWhs)	2,302	1,553	1,314	1,314	6,483
FTRs (MWhs)	4,002	—	—	—	4,002
Natural gas (Dths)	16,523	10,047	815	—	27,385
Coal (tons)	1,415	1,069	799	726	4,009

Fair Value of Financial Instruments

At December 31, 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	2014		2013		2014		2013		2014		2013
Current derivative assets		$30.5		$25.6		$27.4		$20.2		$3.1		$5.4
Non-current derivative assets	8.1		1.1		0.6		0.9		7.5		0.2
Current derivative liabilities	28.1		6.7		16.4		3.0		11.7		3.7
Non-current derivative liabilities	9.5		14.1		3.1		2.2		6.4		11.9

Gains and Losses from Derivative Instruments Not Designated as Hedging Instruments

Changes in unrealized 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
	2014			2013			2012			2014			2013			2012			2014			2013			2012
Regulatory assets		($13.8	)		($14.7	)		($37.9	)		($5.8	)		($6.6	)		($16.8	)		($8.0	)		($8.1	)		($21.1	)
Regulatory liabilities	37.4			22.2			20.3			10.2			11.8			13.5			27.2			10.4			6.8

Credit Risk Related Contingent Features

At December 31, 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):

	2014						2013
	Alliant Energy		IPL		WPL		Alliant Energy		IPL		WPL
Aggregate fair value		$37.6		$19.5		$18.1		$20.8		$5.2		$15.6
Credit support to be posted if triggered	37.4		19.5		17.9		20.8		5.2		15.6

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 at December 31 as follows (in millions):

	Alliant Energy				IPL				WPL
	Gross				Gross				Gross
	(as reported)		Net		(as reported)		Net		(as reported)		Net
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
2013
Derivative assets	26.7		23.5		21.1		19.5		5.6		4.0
Derivative liabilities	20.8		17.6		5.2		3.6		15.6		14.0

IPL [Member]

Derivative [Line Items]

Notional Amounts of Derivative Instruments

As of December 31, 2014, gross notional amounts by delivery year 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):

	2015	2016	2017	2018	Total
Alliant Energy
Electricity (MWhs)	4,067	1,553	1,314	1,314	8,248
FTRs (MWhs)	9,505	—	—	—	9,505
Natural gas (Dths)	56,250	20,225	1,829	—	78,304
Coal (tons)	1,490	1,899	1,073	1,113	5,575
IPL
Electricity (MWhs)	1,765	—	—	—	1,765
FTRs (MWhs)	5,503	—	—	—	5,503
Natural gas (Dths)	39,727	10,178	1,014	—	50,919
Coal (tons)	75	830	274	387	1,566
WPL
Electricity (MWhs)	2,302	1,553	1,314	1,314	6,483
FTRs (MWhs)	4,002	—	—	—	4,002
Natural gas (Dths)	16,523	10,047	815	—	27,385
Coal (tons)	1,415	1,069	799	726	4,009

Fair Value of Financial Instruments

At December 31, 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	2014		2013		2014		2013		2014		2013
Current derivative assets		$30.5		$25.6		$27.4		$20.2		$3.1		$5.4
Non-current derivative assets	8.1		1.1		0.6		0.9		7.5		0.2
Current derivative liabilities	28.1		6.7		16.4		3.0		11.7		3.7
Non-current derivative liabilities	9.5		14.1		3.1		2.2		6.4		11.9

Gains and Losses from Derivative Instruments Not Designated as Hedging Instruments

Changes in unrealized 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
	2014			2013			2012			2014			2013			2012			2014			2013			2012
Regulatory assets		($13.8	)		($14.7	)		($37.9	)		($5.8	)		($6.6	)		($16.8	)		($8.0	)		($8.1	)		($21.1	)
Regulatory liabilities	37.4			22.2			20.3			10.2			11.8			13.5			27.2			10.4			6.8

Credit Risk Related Contingent Features

At December 31, 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):

	2014						2013
	Alliant Energy		IPL		WPL		Alliant Energy		IPL		WPL
Aggregate fair value		$37.6		$19.5		$18.1		$20.8		$5.2		$15.6
Credit support to be posted if triggered	37.4		19.5		17.9		20.8		5.2		15.6

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 at December 31 as follows (in millions):

	Alliant Energy				IPL				WPL
	Gross				Gross				Gross
	(as reported)		Net		(as reported)		Net		(as reported)		Net
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
2013
Derivative assets	26.7		23.5		21.1		19.5		5.6		4.0
Derivative liabilities	20.8		17.6		5.2		3.6		15.6		14.0

WPL [Member]

Derivative [Line Items]

Notional Amounts of Derivative Instruments

As of December 31, 2014, gross notional amounts by delivery year 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):

	2015	2016	2017	2018	Total
Alliant Energy
Electricity (MWhs)	4,067	1,553	1,314	1,314	8,248
FTRs (MWhs)	9,505	—	—	—	9,505
Natural gas (Dths)	56,250	20,225	1,829	—	78,304
Coal (tons)	1,490	1,899	1,073	1,113	5,575
IPL
Electricity (MWhs)	1,765	—	—	—	1,765
FTRs (MWhs)	5,503	—	—	—	5,503
Natural gas (Dths)	39,727	10,178	1,014	—	50,919
Coal (tons)	75	830	274	387	1,566
WPL
Electricity (MWhs)	2,302	1,553	1,314	1,314	6,483
FTRs (MWhs)	4,002	—	—	—	4,002
Natural gas (Dths)	16,523	10,047	815	—	27,385
Coal (tons)	1,415	1,069	799	726	4,009

Fair Value of Financial Instruments

At December 31, 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	2014		2013		2014		2013		2014		2013
Current derivative assets		$30.5		$25.6		$27.4		$20.2		$3.1		$5.4
Non-current derivative assets	8.1		1.1		0.6		0.9		7.5		0.2
Current derivative liabilities	28.1		6.7		16.4		3.0		11.7		3.7
Non-current derivative liabilities	9.5		14.1		3.1		2.2		6.4		11.9

Gains and Losses from Derivative Instruments Not Designated as Hedging Instruments

Changes in unrealized 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
	2014			2013			2012			2014			2013			2012			2014			2013			2012
Regulatory assets		($13.8	)		($14.7	)		($37.9	)		($5.8	)		($6.6	)		($16.8	)		($8.0	)		($8.1	)		($21.1	)
Regulatory liabilities	37.4			22.2			20.3			10.2			11.8			13.5			27.2			10.4			6.8

Credit Risk Related Contingent Features

At December 31, 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):

	2014						2013
	Alliant Energy		IPL		WPL		Alliant Energy		IPL		WPL
Aggregate fair value		$37.6		$19.5		$18.1		$20.8		$5.2		$15.6
Credit support to be posted if triggered	37.4		19.5		17.9		20.8		5.2		15.6

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 at December 31 as follows (in millions):

	Alliant Energy				IPL				WPL
	Gross				Gross				Gross
	(as reported)		Net		(as reported)		Net		(as reported)		Net
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
2013
Derivative assets	26.7		23.5		21.1		19.5		5.6		4.0
Derivative liabilities	20.8		17.6		5.2		3.6		15.6		14.0