Derivative Instruments (Tables)

3 Months Ended

Mar. 31, 2016

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

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

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	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

IPL [Member]

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

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

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	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

WPL [Member]

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

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

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	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