Derivative Instruments (Tables)

6 Months Ended

Jun. 30, 2016

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

As of June 30, 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	4,285	2016-2018	19,876	2016-2017	91,402	2016-2020	3,698	2016-2018	4,536	2016-2017
IPL	434	2016	12,197	2016-2017	50,556	2016-2020	1,306	2016-2018	—	—
WPL	3,851	2016-2018	7,679	2016-2017	40,846	2016-2020	2,392	2016-2018	4,536	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	June 30, 2016		December 31, 2015		June 30, 2016		December 31, 2015		June 30, 2016		December 31, 2015
Current derivative assets		$31.9		$15.1		$25.8		$13.8		$6.1		$1.3
Non-current derivative assets	5.0		3.3		2.3		1.7		2.7		1.6
Current derivative liabilities	23.7		47.3		7.2		18.5		16.5		28.8
Non-current derivative liabilities	13.4		17.3		2.6		4.9		10.8		12.4

IPL [Member]

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

As of June 30, 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	4,285	2016-2018	19,876	2016-2017	91,402	2016-2020	3,698	2016-2018	4,536	2016-2017
IPL	434	2016	12,197	2016-2017	50,556	2016-2020	1,306	2016-2018	—	—
WPL	3,851	2016-2018	7,679	2016-2017	40,846	2016-2020	2,392	2016-2018	4,536	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	June 30, 2016		December 31, 2015		June 30, 2016		December 31, 2015		June 30, 2016		December 31, 2015
Current derivative assets		$31.9		$15.1		$25.8		$13.8		$6.1		$1.3
Non-current derivative assets	5.0		3.3		2.3		1.7		2.7		1.6
Current derivative liabilities	23.7		47.3		7.2		18.5		16.5		28.8
Non-current derivative liabilities	13.4		17.3		2.6		4.9		10.8		12.4

WPL [Member]

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

As of June 30, 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	4,285	2016-2018	19,876	2016-2017	91,402	2016-2020	3,698	2016-2018	4,536	2016-2017
IPL	434	2016	12,197	2016-2017	50,556	2016-2020	1,306	2016-2018	—	—
WPL	3,851	2016-2018	7,679	2016-2017	40,846	2016-2020	2,392	2016-2018	4,536	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	June 30, 2016		December 31, 2015		June 30, 2016		December 31, 2015		June 30, 2016		December 31, 2015
Current derivative assets		$31.9		$15.1		$25.8		$13.8		$6.1		$1.3
Non-current derivative assets	5.0		3.3		2.3		1.7		2.7		1.6
Current derivative liabilities	23.7		47.3		7.2		18.5		16.5		28.8
Non-current derivative liabilities	13.4		17.3		2.6		4.9		10.8		12.4