Derivative Instruments

3 Months Ended

Mar. 31, 2016

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, 2016, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts, FTRs, coal contracts and diesel fuel contracts that were accounted for as commodity derivative instruments were as follows (units in thousands):

	Electricity		FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	5,115	2016-2018	3,768	2016	94,635	2016-2020	4,240	2016-2018	5,292	2016-2017
IPL	660	2016	2,232	2016	49,747	2016-2020	1,661	2016-2018	—	—
WPL	4,455	2016-2018	1,536	2016	44,888	2016-2020	2,579	2016-2018	5,292	2016-2017

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, 2016		December 31, 2015		March 31, 2016		December 31, 2015		March 31, 2016		December 31, 2015
Current derivative assets		$6.1		$15.1		$4.8		$13.8		$1.3		$1.3
Non-current derivative assets	1.6		3.3		1.0		1.7		0.6		1.6
Current derivative liabilities	56.3		47.3		18.7		18.5		37.6		28.8
Non-current derivative liabilities	27.7		17.3		4.6		4.9		23.1		12.4

Unrealized gains and losses from commodity derivative instruments were recorded with offsets to regulatory assets or regulatory liabilities on the balance sheets. Refer to Notes 2 and 11 for further discussion.

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. At March 31, 2016 and December 31, 2015, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than 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.

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, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at March 31, 2016 and December 31, 2015. 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, 2016, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts, FTRs, coal contracts and diesel fuel contracts that were accounted for as commodity derivative instruments were as follows (units in thousands):

	Electricity		FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	5,115	2016-2018	3,768	2016	94,635	2016-2020	4,240	2016-2018	5,292	2016-2017
IPL	660	2016	2,232	2016	49,747	2016-2020	1,661	2016-2018	—	—
WPL	4,455	2016-2018	1,536	2016	44,888	2016-2020	2,579	2016-2018	5,292	2016-2017

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, 2016		December 31, 2015		March 31, 2016		December 31, 2015		March 31, 2016		December 31, 2015
Current derivative assets		$6.1		$15.1		$4.8		$13.8		$1.3		$1.3
Non-current derivative assets	1.6		3.3		1.0		1.7		0.6		1.6
Current derivative liabilities	56.3		47.3		18.7		18.5		37.6		28.8
Non-current derivative liabilities	27.7		17.3		4.6		4.9		23.1		12.4

Unrealized gains and losses from commodity derivative instruments were recorded with offsets to regulatory assets or regulatory liabilities on the balance sheets. Refer to Notes 2 and 11 for further discussion.

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. At March 31, 2016 and December 31, 2015, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than 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.

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, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at March 31, 2016 and December 31, 2015. 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, 2016, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts, FTRs, coal contracts and diesel fuel contracts that were accounted for as commodity derivative instruments were as follows (units in thousands):

	Electricity		FTRs		Natural Gas		Coal		Diesel Fuel
	MWhs	Years	MWhs	Years	Dths	Years	Tons	Years	Gallons	Years
Alliant Energy	5,115	2016-2018	3,768	2016	94,635	2016-2020	4,240	2016-2018	5,292	2016-2017
IPL	660	2016	2,232	2016	49,747	2016-2020	1,661	2016-2018	—	—
WPL	4,455	2016-2018	1,536	2016	44,888	2016-2020	2,579	2016-2018	5,292	2016-2017

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, 2016		December 31, 2015		March 31, 2016		December 31, 2015		March 31, 2016		December 31, 2015
Current derivative assets		$6.1		$15.1		$4.8		$13.8		$1.3		$1.3
Non-current derivative assets	1.6		3.3		1.0		1.7		0.6		1.6
Current derivative liabilities	56.3		47.3		18.7		18.5		37.6		28.8
Non-current derivative liabilities	27.7		17.3		4.6		4.9		23.1		12.4

Unrealized gains and losses from commodity derivative instruments were recorded with offsets to regulatory assets or regulatory liabilities on the balance sheets. Refer to Notes 2 and 11 for further discussion.

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. At March 31, 2016 and December 31, 2015, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than 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.

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, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at March 31, 2016 and December 31, 2015. 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.