Derivative Instruments

3 Months Ended

Mar. 31, 2015

Derivative Instruments [Line Items]

Derivative Instruments

DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Purpose - Derivative instruments are periodically used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. Refer to Note 11 for detailed discussion of derivative instruments.

Notional Amounts - As of March 31, 2015, 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)	3,530	2,870	1,314	1,314	9,028
FTRs (MWhs)	3,478	—	—	—	3,478
Natural gas (Dths)	42,989	27,423	7,126	—	77,538
Coal (tons)	1,118	2,044	1,073	1,113	5,348
IPL
Electricity (MWhs)	1,612	439	—	—	2,051
FTRs (MWhs)	2,041	—	—	—	2,041
Natural gas (Dths)	26,967	13,176	2,758	—	42,901
Coal (tons)	56	830	274	387	1,547
WPL
Electricity (MWhs)	1,918	2,431	1,314	1,314	6,977
FTRs (MWhs)	1,437	—	—	—	1,437
Natural gas (Dths)	16,022	14,247	4,368	—	34,637
Coal (tons)	1,062	1,214	799	726	3,801

Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities. 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	March 31, 2015		December 31, 2014		March 31, 2015		December 31, 2014		March 31, 2015		December 31, 2014
Current derivative assets		$9.1		$30.5		$5.6		$27.4		$3.5		$3.1
Non-current derivative assets	7.8		8.1		0.9		0.6		6.9		7.5
Current derivative liabilities	24.4		28.1		13.8		16.4		10.6		11.7
Non-current derivative liabilities	18.3		9.5		6.2		3.1		12.1		6.4

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
Three Months Ended March 31	2015			2014		2015			2014		2015			2014
Regulatory assets		($20.9	)		$10.1		($11.7	)		$5.5		($9.2	)		$4.6
Regulatory liabilities	2.2			48.1		(1.4		)	12.1		3.6			36.0

Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. 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
	March 31, 2015		December 31, 2014		March 31, 2015		December 31, 2014		March 31, 2015		December 31, 2014
Aggregate fair value		$42.7		$37.6		$20.0		$19.5		$22.7		$18.1
Credit support to be posted if triggered	42.2		37.4		20.0		19.5		22.2		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
March 31, 2015
Derivative assets		$16.9		$10.3		$6.5		$5.1		$10.4		$5.2
Derivative liabilities	42.7		36.1		20.0		18.6		22.7		17.5
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

Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement.

IPL [Member]

Derivative Instruments [Line Items]

Derivative Instruments

DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Purpose - Derivative instruments are periodically used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. Refer to Note 11 for detailed discussion of derivative instruments.

Notional Amounts - As of March 31, 2015, 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)	3,530	2,870	1,314	1,314	9,028
FTRs (MWhs)	3,478	—	—	—	3,478
Natural gas (Dths)	42,989	27,423	7,126	—	77,538
Coal (tons)	1,118	2,044	1,073	1,113	5,348
IPL
Electricity (MWhs)	1,612	439	—	—	2,051
FTRs (MWhs)	2,041	—	—	—	2,041
Natural gas (Dths)	26,967	13,176	2,758	—	42,901
Coal (tons)	56	830	274	387	1,547
WPL
Electricity (MWhs)	1,918	2,431	1,314	1,314	6,977
FTRs (MWhs)	1,437	—	—	—	1,437
Natural gas (Dths)	16,022	14,247	4,368	—	34,637
Coal (tons)	1,062	1,214	799	726	3,801

Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities. 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	March 31, 2015		December 31, 2014		March 31, 2015		December 31, 2014		March 31, 2015		December 31, 2014
Current derivative assets		$9.1		$30.5		$5.6		$27.4		$3.5		$3.1
Non-current derivative assets	7.8		8.1		0.9		0.6		6.9		7.5
Current derivative liabilities	24.4		28.1		13.8		16.4		10.6		11.7
Non-current derivative liabilities	18.3		9.5		6.2		3.1		12.1		6.4

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
Three Months Ended March 31	2015			2014		2015			2014		2015			2014
Regulatory assets		($20.9	)		$10.1		($11.7	)		$5.5		($9.2	)		$4.6
Regulatory liabilities	2.2			48.1		(1.4		)	12.1		3.6			36.0

Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. 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
	March 31, 2015		December 31, 2014		March 31, 2015		December 31, 2014		March 31, 2015		December 31, 2014
Aggregate fair value		$42.7		$37.6		$20.0		$19.5		$22.7		$18.1
Credit support to be posted if triggered	42.2		37.4		20.0		19.5		22.2		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
March 31, 2015
Derivative assets		$16.9		$10.3		$6.5		$5.1		$10.4		$5.2
Derivative liabilities	42.7		36.1		20.0		18.6		22.7		17.5
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

Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement.

WPL [Member]

Derivative Instruments [Line Items]

Derivative Instruments

DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Purpose - Derivative instruments are periodically used for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. Refer to Note 11 for detailed discussion of derivative instruments.

Notional Amounts - As of March 31, 2015, 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)	3,530	2,870	1,314	1,314	9,028
FTRs (MWhs)	3,478	—	—	—	3,478
Natural gas (Dths)	42,989	27,423	7,126	—	77,538
Coal (tons)	1,118	2,044	1,073	1,113	5,348
IPL
Electricity (MWhs)	1,612	439	—	—	2,051
FTRs (MWhs)	2,041	—	—	—	2,041
Natural gas (Dths)	26,967	13,176	2,758	—	42,901
Coal (tons)	56	830	274	387	1,547
WPL
Electricity (MWhs)	1,918	2,431	1,314	1,314	6,977
FTRs (MWhs)	1,437	—	—	—	1,437
Natural gas (Dths)	16,022	14,247	4,368	—	34,637
Coal (tons)	1,062	1,214	799	726	3,801

Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities. 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	March 31, 2015		December 31, 2014		March 31, 2015		December 31, 2014		March 31, 2015		December 31, 2014
Current derivative assets		$9.1		$30.5		$5.6		$27.4		$3.5		$3.1
Non-current derivative assets	7.8		8.1		0.9		0.6		6.9		7.5
Current derivative liabilities	24.4		28.1		13.8		16.4		10.6		11.7
Non-current derivative liabilities	18.3		9.5		6.2		3.1		12.1		6.4

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
Three Months Ended March 31	2015			2014		2015			2014		2015			2014
Regulatory assets		($20.9	)		$10.1		($11.7	)		$5.5		($9.2	)		$4.6
Regulatory liabilities	2.2			48.1		(1.4		)	12.1		3.6			36.0

Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. 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
	March 31, 2015		December 31, 2014		March 31, 2015		December 31, 2014		March 31, 2015		December 31, 2014
Aggregate fair value		$42.7		$37.6		$20.0		$19.5		$22.7		$18.1
Credit support to be posted if triggered	42.2		37.4		20.0		19.5		22.2		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
March 31, 2015
Derivative assets		$16.9		$10.3		$6.5		$5.1		$10.4		$5.2
Derivative liabilities	42.7		36.1		20.0		18.6		22.7		17.5
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

Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement.