Derivative Instruments (Tables)

9 Months Ended

Sep. 30, 2016

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

As of September 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	3,427	2016-2018	14,437	2016-2017	82,277	2016-2020	4,640	2016-2019	3,780	2016-2017
IPL	187	2016	8,865	2016-2017	47,141	2016-2020	2,202	2016-2019	—	—
WPL	3,240	2016-2018	5,572	2016-2017	35,136	2016-2020	2,438	2016-2018	3,780	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	September 30, 2016		December 31, 2015		September 30, 2016		December 31, 2015		September 30, 2016		December 31, 2015
Current derivative assets		$25.1		$15.1		$20.5		$13.8		$4.6		$1.3
Non-current derivative assets	2.7		3.3		1.7		1.7		1.0		1.6
Current derivative liabilities	21.2		47.3		5.4		18.5		15.8		28.8
Non-current derivative liabilities	15.7		17.3		3.6		4.9		12.1		12.4

IPL [Member]

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

As of September 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	3,427	2016-2018	14,437	2016-2017	82,277	2016-2020	4,640	2016-2019	3,780	2016-2017
IPL	187	2016	8,865	2016-2017	47,141	2016-2020	2,202	2016-2019	—	—
WPL	3,240	2016-2018	5,572	2016-2017	35,136	2016-2020	2,438	2016-2018	3,780	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	September 30, 2016		December 31, 2015		September 30, 2016		December 31, 2015		September 30, 2016		December 31, 2015
Current derivative assets		$25.1		$15.1		$20.5		$13.8		$4.6		$1.3
Non-current derivative assets	2.7		3.3		1.7		1.7		1.0		1.6
Current derivative liabilities	21.2		47.3		5.4		18.5		15.8		28.8
Non-current derivative liabilities	15.7		17.3		3.6		4.9		12.1		12.4

WPL [Member]

Derivative Instruments [Line Items]

Notional Amounts Of Derivative Instruments

As of September 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	3,427	2016-2018	14,437	2016-2017	82,277	2016-2020	4,640	2016-2019	3,780	2016-2017
IPL	187	2016	8,865	2016-2017	47,141	2016-2020	2,202	2016-2019	—	—
WPL	3,240	2016-2018	5,572	2016-2017	35,136	2016-2020	2,438	2016-2018	3,780	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	September 30, 2016		December 31, 2015		September 30, 2016		December 31, 2015		September 30, 2016		December 31, 2015
Current derivative assets		$25.1		$15.1		$20.5		$13.8		$4.6		$1.3
Non-current derivative assets	2.7		3.3		1.7		1.7		1.0		1.6
Current derivative liabilities	21.2		47.3		5.4		18.5		15.8		28.8
Non-current derivative liabilities	15.7		17.3		3.6		4.9		12.1		12.4