Derivative Instruments

3 Months Ended

Mar. 31, 2013

Derivative [Line Items]

Derivative Instruments

DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Purpose - Alliant Energy, IPL and WPL periodically use derivative instruments for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. Refer to Note 10 for detailed discussion of Alliant Energy’s, IPL’s and WPL’s derivative instruments as of March 31, 2013 and December 31, 2012.

Notional Amounts - As of March 31, 2013, 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):

	2013	2014	2015	2016	Total
Alliant Energy
Electricity (megawatt-hours (MWhs))	3,431	3,164	876	—	7,471
FTRs (MWs)	11	—	—	—	11
Natural gas (dekatherms (Dths))	66,884	10,130	1,880	455	79,349
Coal (tons)	672	981	562	—	2,215
IPL
Electricity (MWhs)	1,987	1,024	—	—	3,011
FTRs (MWs)	6	—	—	—	6
Natural gas (Dths)	52,116	5,765	1,430	455	59,766
WPL
Electricity (MWhs)	1,444	2,140	876	—	4,460
FTRs (MWs)	5	—	—	—	5
Natural gas (Dths)	14,768	4,365	450	—	19,583
Coal (tons)	672	981	562	—	2,215

The notional amounts in the above table were computed by aggregating the absolute value of purchase and sale positions within commodities for each delivery year.

Financial Statement Presentation - Alliant Energy, IPL and WPL record derivative instruments at fair value each reporting date on the balance sheet as assets or liabilities. The fair values of current derivative assets were included in “Other current assets,” non-current derivative assets were included in “Deferred charges and other,” current derivative liabilities were included in “Other current liabilities” and non-current derivative liabilities were included in “Other long-term liabilities and deferred credits” on the Condensed Consolidated Balance Sheets as follows (in millions):

	Alliant Energy				IPL				WPL
Commodity contracts	March 31, 2013		December 31, 2012		March 31, 2013		December 31, 2012		March 31, 2013		December 31, 2012
Current derivative assets		$17.5		$23.5		$10.9		$17.0		$6.6		$6.5
Non-current derivative assets	6.1		2.7		1.6		0.5		4.5		2.2
Current derivative liabilities	13.5		31.1		5.7		14.1		7.8		17.0
Non-current derivative liabilities	3.6		9.3		0.4		2.0		3.2		7.3

Changes in unrealized gains (losses) from commodity derivative instruments not designated as hedging instruments were recorded with offsets to regulatory assets or regulatory liabilities on the Condensed Consolidated Balance Sheets as follows (in millions):

	Alliant Energy					IPL					WPL
	2013		2012			2013		2012			2013		2012
Three Months Ended March 31
Regulatory assets		$9.5		($39.7	)		$2.7		($22.2	)		$6.8		($17.5	)
Regulatory liabilities	16.4		1.4			8.8		—			7.6		1.4

Net unrealized gains and losses from commodity contracts during the three months ended March 31, 2013 and 2012 were primarily due to impacts of increases and decreases in forward electricity and natural gas prices during such periods, respectively.

Credit Risk-related Contingent Features - Alliant Energy, IPL and WPL have entered into various agreements that contain credit risk-related contingent features including requirements for them to maintain certain credit ratings from each of the major credit rating agencies and/or limitations on their liability positions under the various agreements based upon their credit ratings. In the event of a downgrade in their credit ratings or if their liability positions exceed certain contractual limits, Alliant Energy, IPL or WPL may need to provide credit support in the form of letters of credit or cash collateral up to the amount of their exposure under the contracts, or may need to unwind the contracts and pay the underlying liability positions.

Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. The aggregate fair value of all derivatives with credit risk-related contingent features that were in a net liability position on March 31, 2013 was $17.1 million, $6.1 million and $11.0 million for Alliant Energy, IPL and WPL, respectively. At March 31, 2013, Alliant Energy, IPL and WPL all had investment-grade credit ratings. If the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered on March 31, 2013, Alliant Energy, IPL and WPL would be required to post $17.1 million, $6.1 million and $11.0 million, respectively, of credit support to their counterparties.

Balance Sheet Offsetting - Alliant Energy, IPL and WPL do not net derivative instruments subject to a master netting arrangement by counterparty on the Condensed Consolidated Balance Sheets. Alliant Energy, IPL and WPL also do not offset fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement. However, if Alliant Energy, IPL and WPL did net derivative instruments and related cash collateral by counterparty, derivative assets and derivative liabilities related to commodity contracts would have been presented on their Condensed Consolidated Balance Sheets as follows (in millions):

	Alliant Energy				IPL				WPL
	Gross				Gross				Gross
	(as reported)		Net		(as reported)		Net		(as reported)		Net
March 31, 2013
Derivative assets		$23.6		$16.3		$12.5		$9.0		$11.1		$7.3
Derivative liabilities	17.1		9.8		6.1		2.6		11.0		7.2
December 31, 2012
Derivative assets	26.2		19.3		17.5		14.5		8.7		4.8
Derivative liabilities	40.4		33.0		16.1		12.6		24.3		20.4

As of March 31, 2013 and December 31, 2012, both Alliant Energy’s and IPL’s net derivative liabilities in the above table include $0 and $0.5 million, respectively, of cash collateral posted by IPL. Trade receivables and payables associated with derivative assets and derivative liabilities are also subject to a master netting arrangement. As of March 31, 2013 and December 31, 2012, these trade receivables and payables were insignificant and were not included in the above table.

IPL [Member]

Derivative [Line Items]

Derivative Instruments

DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Purpose - Alliant Energy, IPL and WPL periodically use derivative instruments for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. Refer to Note 10 for detailed discussion of Alliant Energy’s, IPL’s and WPL’s derivative instruments as of March 31, 2013 and December 31, 2012.

Notional Amounts - As of March 31, 2013, 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):

	2013	2014	2015	2016	Total
Alliant Energy
Electricity (megawatt-hours (MWhs))	3,431	3,164	876	—	7,471
FTRs (MWs)	11	—	—	—	11
Natural gas (dekatherms (Dths))	66,884	10,130	1,880	455	79,349
Coal (tons)	672	981	562	—	2,215
IPL
Electricity (MWhs)	1,987	1,024	—	—	3,011
FTRs (MWs)	6	—	—	—	6
Natural gas (Dths)	52,116	5,765	1,430	455	59,766
WPL
Electricity (MWhs)	1,444	2,140	876	—	4,460
FTRs (MWs)	5	—	—	—	5
Natural gas (Dths)	14,768	4,365	450	—	19,583
Coal (tons)	672	981	562	—	2,215

The notional amounts in the above table were computed by aggregating the absolute value of purchase and sale positions within commodities for each delivery year.

Financial Statement Presentation - Alliant Energy, IPL and WPL record derivative instruments at fair value each reporting date on the balance sheet as assets or liabilities. The fair values of current derivative assets were included in “Other current assets,” non-current derivative assets were included in “Deferred charges and other,” current derivative liabilities were included in “Other current liabilities” and non-current derivative liabilities were included in “Other long-term liabilities and deferred credits” on the Condensed Consolidated Balance Sheets as follows (in millions):

	Alliant Energy				IPL				WPL
Commodity contracts	March 31, 2013		December 31, 2012		March 31, 2013		December 31, 2012		March 31, 2013		December 31, 2012
Current derivative assets		$17.5		$23.5		$10.9		$17.0		$6.6		$6.5
Non-current derivative assets	6.1		2.7		1.6		0.5		4.5		2.2
Current derivative liabilities	13.5		31.1		5.7		14.1		7.8		17.0
Non-current derivative liabilities	3.6		9.3		0.4		2.0		3.2		7.3

Changes in unrealized gains (losses) from commodity derivative instruments not designated as hedging instruments were recorded with offsets to regulatory assets or regulatory liabilities on the Condensed Consolidated Balance Sheets as follows (in millions):

	Alliant Energy					IPL					WPL
	2013		2012			2013		2012			2013		2012
Three Months Ended March 31
Regulatory assets		$9.5		($39.7	)		$2.7		($22.2	)		$6.8		($17.5	)
Regulatory liabilities	16.4		1.4			8.8		—			7.6		1.4

Net unrealized gains and losses from commodity contracts during the three months ended March 31, 2013 and 2012 were primarily due to impacts of increases and decreases in forward electricity and natural gas prices during such periods, respectively.

Credit Risk-related Contingent Features - Alliant Energy, IPL and WPL have entered into various agreements that contain credit risk-related contingent features including requirements for them to maintain certain credit ratings from each of the major credit rating agencies and/or limitations on their liability positions under the various agreements based upon their credit ratings. In the event of a downgrade in their credit ratings or if their liability positions exceed certain contractual limits, Alliant Energy, IPL or WPL may need to provide credit support in the form of letters of credit or cash collateral up to the amount of their exposure under the contracts, or may need to unwind the contracts and pay the underlying liability positions.

Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. The aggregate fair value of all derivatives with credit risk-related contingent features that were in a net liability position on March 31, 2013 was $17.1 million, $6.1 million and $11.0 million for Alliant Energy, IPL and WPL, respectively. At March 31, 2013, Alliant Energy, IPL and WPL all had investment-grade credit ratings. If the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered on March 31, 2013, Alliant Energy, IPL and WPL would be required to post $17.1 million, $6.1 million and $11.0 million, respectively, of credit support to their counterparties.

Balance Sheet Offsetting - Alliant Energy, IPL and WPL do not net derivative instruments subject to a master netting arrangement by counterparty on the Condensed Consolidated Balance Sheets. Alliant Energy, IPL and WPL also do not offset fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement. However, if Alliant Energy, IPL and WPL did net derivative instruments and related cash collateral by counterparty, derivative assets and derivative liabilities related to commodity contracts would have been presented on their Condensed Consolidated Balance Sheets as follows (in millions):

	Alliant Energy				IPL				WPL
	Gross				Gross				Gross
	(as reported)		Net		(as reported)		Net		(as reported)		Net
March 31, 2013
Derivative assets		$23.6		$16.3		$12.5		$9.0		$11.1		$7.3
Derivative liabilities	17.1		9.8		6.1		2.6		11.0		7.2
December 31, 2012
Derivative assets	26.2		19.3		17.5		14.5		8.7		4.8
Derivative liabilities	40.4		33.0		16.1		12.6		24.3		20.4

As of March 31, 2013 and December 31, 2012, both Alliant Energy’s and IPL’s net derivative liabilities in the above table include $0 and $0.5 million, respectively, of cash collateral posted by IPL. Trade receivables and payables associated with derivative assets and derivative liabilities are also subject to a master netting arrangement. As of March 31, 2013 and December 31, 2012, these trade receivables and payables were insignificant and were not included in the above table.

WPL [Member]

Derivative [Line Items]

Derivative Instruments

DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Purpose - Alliant Energy, IPL and WPL periodically use derivative instruments for risk management purposes to mitigate exposures to fluctuations in certain commodity prices and transmission congestion costs. Refer to Note 10 for detailed discussion of Alliant Energy’s, IPL’s and WPL’s derivative instruments as of March 31, 2013 and December 31, 2012.

Notional Amounts - As of March 31, 2013, 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):

	2013	2014	2015	2016	Total
Alliant Energy
Electricity (megawatt-hours (MWhs))	3,431	3,164	876	—	7,471
FTRs (MWs)	11	—	—	—	11
Natural gas (dekatherms (Dths))	66,884	10,130	1,880	455	79,349
Coal (tons)	672	981	562	—	2,215
IPL
Electricity (MWhs)	1,987	1,024	—	—	3,011
FTRs (MWs)	6	—	—	—	6
Natural gas (Dths)	52,116	5,765	1,430	455	59,766
WPL
Electricity (MWhs)	1,444	2,140	876	—	4,460
FTRs (MWs)	5	—	—	—	5
Natural gas (Dths)	14,768	4,365	450	—	19,583
Coal (tons)	672	981	562	—	2,215

The notional amounts in the above table were computed by aggregating the absolute value of purchase and sale positions within commodities for each delivery year.

Financial Statement Presentation - Alliant Energy, IPL and WPL record derivative instruments at fair value each reporting date on the balance sheet as assets or liabilities. The fair values of current derivative assets were included in “Other current assets,” non-current derivative assets were included in “Deferred charges and other,” current derivative liabilities were included in “Other current liabilities” and non-current derivative liabilities were included in “Other long-term liabilities and deferred credits” on the Condensed Consolidated Balance Sheets as follows (in millions):

	Alliant Energy				IPL				WPL
Commodity contracts	March 31, 2013		December 31, 2012		March 31, 2013		December 31, 2012		March 31, 2013		December 31, 2012
Current derivative assets		$17.5		$23.5		$10.9		$17.0		$6.6		$6.5
Non-current derivative assets	6.1		2.7		1.6		0.5		4.5		2.2
Current derivative liabilities	13.5		31.1		5.7		14.1		7.8		17.0
Non-current derivative liabilities	3.6		9.3		0.4		2.0		3.2		7.3

Changes in unrealized gains (losses) from commodity derivative instruments not designated as hedging instruments were recorded with offsets to regulatory assets or regulatory liabilities on the Condensed Consolidated Balance Sheets as follows (in millions):

	Alliant Energy					IPL					WPL
	2013		2012			2013		2012			2013		2012
Three Months Ended March 31
Regulatory assets		$9.5		($39.7	)		$2.7		($22.2	)		$6.8		($17.5	)
Regulatory liabilities	16.4		1.4			8.8		—			7.6		1.4

Net unrealized gains and losses from commodity contracts during the three months ended March 31, 2013 and 2012 were primarily due to impacts of increases and decreases in forward electricity and natural gas prices during such periods, respectively.

Credit Risk-related Contingent Features - Alliant Energy, IPL and WPL have entered into various agreements that contain credit risk-related contingent features including requirements for them to maintain certain credit ratings from each of the major credit rating agencies and/or limitations on their liability positions under the various agreements based upon their credit ratings. In the event of a downgrade in their credit ratings or if their liability positions exceed certain contractual limits, Alliant Energy, IPL or WPL may need to provide credit support in the form of letters of credit or cash collateral up to the amount of their exposure under the contracts, or may need to unwind the contracts and pay the underlying liability positions.

Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. The aggregate fair value of all derivatives with credit risk-related contingent features that were in a net liability position on March 31, 2013 was $17.1 million, $6.1 million and $11.0 million for Alliant Energy, IPL and WPL, respectively. At March 31, 2013, Alliant Energy, IPL and WPL all had investment-grade credit ratings. If the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered on March 31, 2013, Alliant Energy, IPL and WPL would be required to post $17.1 million, $6.1 million and $11.0 million, respectively, of credit support to their counterparties.

Balance Sheet Offsetting - Alliant Energy, IPL and WPL do not net derivative instruments subject to a master netting arrangement by counterparty on the Condensed Consolidated Balance Sheets. Alliant Energy, IPL and WPL also do not offset fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement. However, if Alliant Energy, IPL and WPL did net derivative instruments and related cash collateral by counterparty, derivative assets and derivative liabilities related to commodity contracts would have been presented on their Condensed Consolidated Balance Sheets as follows (in millions):

	Alliant Energy				IPL				WPL
	Gross				Gross				Gross
	(as reported)		Net		(as reported)		Net		(as reported)		Net
March 31, 2013
Derivative assets		$23.6		$16.3		$12.5		$9.0		$11.1		$7.3
Derivative liabilities	17.1		9.8		6.1		2.6		11.0		7.2
December 31, 2012
Derivative assets	26.2		19.3		17.5		14.5		8.7		4.8
Derivative liabilities	40.4		33.0		16.1		12.6		24.3		20.4

As of March 31, 2013 and December 31, 2012, both Alliant Energy’s and IPL’s net derivative liabilities in the above table include $0 and $0.5 million, respectively, of cash collateral posted by IPL. Trade receivables and payables associated with derivative assets and derivative liabilities are also subject to a master netting arrangement. As of March 31, 2013 and December 31, 2012, these trade receivables and payables were insignificant and were not included in the above table.