Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2011

Fair Value Measurements

Fair Value Of Financial Instruments

	Alliant Energy				IPL				WPL
	Carrying Amount		Fair Value		Carrying Amount		Fair Value		Carrying Amount		Fair Value
Sep. 30, 2011
Assets:
Money market fund investments	$	18.2	$	18.2	$	—	$	—	$	18.2	$	18.2
Derivative assets (Note 10)		25.1		25.1		16.7		16.7		8.0		8.0
Deferred proceeds (sales of receivables) (Note 3)		87.4		87.4		87.4		87.4		—		—
Available-for-sale securities		1.8		1.8		1.8		1.8		—		—
Capitalization and liabilities:
Long-term debt (including current maturities)		2,705.0		3,315.1		1,308.9		1,563.7		1,082.1		1,421.3
Cumulative preferred stock of subsidiaries (Note 6(b))		205.1		222.8		145.1		166.5		60.0		56.3
Derivative liabilities (Note 10)		52.4		52.4		20.7		20.7		31.7		31.7
Dec. 31, 2010
Assets:
Money market fund investments		128.3		128.3		5.6		5.6		—		—
Derivative assets (Note 10)		20.9		20.9		12.9		12.9		8.0		8.0
Deferred proceeds (sales of receivables) (Note 3)		152.9		152.9		152.9		152.9		—		—
Available-for-sale securities		2.1		2.1		2.1		2.1		—		—
Capitalization and liabilities:
Long-term debt (including current maturities)		2,704.7		2,958.6		1,308.6		1,417.0		1,081.7		1,219.6
Cumulative preferred stock of subsidiaries (Note 6(b))		243.8		266.7		183.8		210.7		60.0		56.0
Derivative liabilities (Note 10)		67.3		67.3		24.0		24.0		43.3		43.3

Recurring Fair Value Measurements

Alliant Energy	Sep. 30, 2011								Dec. 31, 2010
	Fair Value		Level 1		Level 2		Level 3		Fair Value		Level 1		Level 2		Level 3
Assets:
Money market fund investments	$	18.2	$	18.2	$	—	$	—	$	128.3	$	128.3	$	—	$	—
Derivative assets:
Commodity contracts		24.7		—		7.7		17.0		16.1		—		10.0		6.1
Foreign exchange contracts		0.4		—		—		0.4		4.8		—		—		4.8
Total derivative assets		25.1		—		7.7		17.4		20.9		—		10.0		10.9
Deferred proceeds		87.4		—		—		87.4		152.9		—		—		152.9
Available-for-sale securities		1.8		0.8		0.9		0.1		2.1		0.6		1.4		0.1
Liabilities:
Derivative liabilities:
Commodity contracts		52.4		—		47.3		5.1		67.2		—		63.9		3.3
Foreign exchange contracts		—		—		—		—		0.1		—		—		0.1
Total derivative liabilities		52.4		—		47.3		5.1		67.3		—		63.9		3.4

IPL	Sep. 30, 2011								Dec. 31, 2010
	Fair Value		Level 1		Level 2		Level 3		Fair Value		Level 1		Level 2		Level 3
Assets:
Money market fund investments	$	—	$	—	$	—	$	—	$	5.6	$	5.6	$	—	$	—
Derivative assets:
Commodity contracts		16.7		—		2.9		13.8		8.1		—		3.6		4.5
Foreign exchange contracts		—		—		—		—		4.8		—		—		4.8
Total derivative assets		16.7		—		2.9		13.8		12.9		—		3.6		9.3
Deferred proceeds		87.4		—		—		87.4		152.9		—		—		152.9
Available-for-sale securities		1.8		0.8		0.9		0.1		2.1		0.6		1.4		0.1
Liabilities:
Derivative liabilities:
Commodity contracts		20.7		—		19.3		1.4		24.0		—		23.8		0.2

WPL	Sep. 30, 2011								Dec. 31, 2010
	Fair Value		Level 1		Level 2		Level 3		Fair Value		Level 1		Level 2		Level 3
Assets:
Money market fund investments	$	18.2	$	18.2	$	—	$	—	$	—	$	—	$	—	$	—
Derivative assets:
Commodity contracts		8.0		—		4.8		3.2		8.0		—		6.4		1.6
Liabilities:
Derivative liabilities:
Commodity contracts		31.7		—		28.0		3.7		43.2		—		40.1		3.1
Foreign exchange contracts		—		—		—		—		0.1		—		—		0.1
Total derivative liabilities		31.7		—		28.0		3.7		43.3		—		40.1		3.2

Fair Value Measurements Using Significant Unobservable Inputs

Alliant Energy	Derivative Assets and (Liabilities), net
	Commodity Contracts						Foreign Contracts						Deferred Proceeds				Available-for-sale Securities
Three months ended Sep. 30	2011			2010			2011			2010			2011		2010		2011		2010
Beginning balance, July 1	$	18.1		$	10.3		$	2.1		$	7.9		$	66.4	$	68.1	$	0.1	$	0.1
Total losses (realized/unrealized) included in changes in net assets (a)		(0.1	)		(0.4	)		—			—			—		—		—		—
Transfers in and/or out of Level 3 (b)		—			(0.2	)		—			—			—		—		—		—
Settlements (c)		(6.1	)		(3.8	)		(1.7	)		(0.6	)		21.0		46.5		—		—
Ending balance, Sep. 30	$	11.9		$	5.9		$	0.4		$	7.3		$	87.4	$	114.6	$	0.1	$	0.1
The amount of total losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at Sep. 30 (a)	($	0.1	)	($	0.4	)	$	—		$	—		$	—	$	—	$	—	$	—

	Derivative Assets and (Liabilities), net
Alliant Energy	Commodity Contracts						Foreign Contracts					Deferred Proceeds					Available-for-sale Securities
Nine months ended Sep. 30	2011			2010			2011			2010		2011			2010		2011		2010
Beginning balance, Jan. 1	$	2.8		$	2.6		$	4.7		$	3.1	$	152.9		$	—	$	0.1	$	0.1
Total gains (realized/unrealized) included in changes in net assets (a)		—			11.6			—			3.8		—			—		—		—
Transfers in and/or out of Level 3 (b)		0.2			(0.1	)		—			—		—			—		—		—
Purchases		21.8			—			—			—		—			—		—		—
Settlements (c)		(12.9	)		(8.2	)		(4.3	)		0.4		(65.5	)		114.6		—		—
Ending balance, Sep. 30	$	11.9		$	5.9		$	0.4		$	7.3	$	87.4		$	114.6	$	0.1	$	0.1
The amount of total gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at Sep. 30 (a)	$	—		$	11.6		$	—		$	3.8	$	—		$	—	$	—	$	—

	Derivative Assets and (Liabilities), net
IPL	Commodity Contracts						Foreign Contracts					Deferred Proceeds				Available-for-sale Securities
Three months ended Sep. 30	2011			2010			2011		2010			2011		2010		2011		2010
Beginning balance, July 1	$	17.5		$	9.7		$	—	$	8.4		$	66.4	$	68.1	$	0.1	$	0.1
Total gains (losses) (realized/unrealized) included in changes in net assets (a)		(0.1	)		0.2			—		—			—		—		—		—
Transfers in and/or out of Level 3 (b)		—			0.1			—		—			—		—		—		—
Settlements (c)		(5.0	)		(3.0	)		—		(0.9	)		21.0		46.5		—		—
Ending balance, Sep. 30	$	12.4		$	7.0		$	—	$	7.5		$	87.4	$	114.6	$	0.1	$	0.1
The amount of total gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at Sep. 30 (a)	($	0.1	)	$	0.2		$	—	$	—		$	—	$	—	$	—	$	—

	Derivative Assets and (Liabilities), net
IPL	Commodity Contracts						Foreign Contracts						Deferred Proceeds					Available-for-sale Securities
Nine months ended Sep. 30	2011			2010			2011			2010			2011			2010		2011		2010
Beginning balance, Jan. 1	$	4.3		$	1.4		$	4.8		$	4.6		$	152.9		$	—	$	0.1	$	0.1
Total gains (realized/unrealized) included in changes in net assets (a)		0.4			10.8			—			3.8			—			—		—		—
Transfers in and/or out of Level 3 (b)		—			0.1			—			—			—			—		—		—
Purchases		18.1			—			—			—			—			—		—		—
Sales (d)		—			—			(2.1	)		—			—			—		—		—
Settlements (c)		(10.4	)		(5.3	)		(2.7	)		(0.9	)		(65.5	)		114.6		—		—
Ending balance, Sep. 30	$	12.4		$	7.0		$	—		$	7.5		$	87.4		$	114.6	$	0.1	$	0.1
The amount of total gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at Sep. 30 (a)	$	0.4		$	10.8		$	—		$	3.8		$	—		$	—	$	—	$	—

WPL	Derivative Assets and (Liabilities), net
	Commodity Contracts						Foreign Contracts
Three months ended Sep. 30	2011			2010			2011			2010
Beginning balance, July 1	$	0.6		$	0.6		$	—		($	0.5	)
Total losses (realized/unrealized) included in changes in net assets (a)		—			(0.6	)		—			—
Transfers in and/or out of Level 3 (b)		—			(0.3	)		—			—
Settlements		(1.1	)		(0.8	)		—			0.3
Ending balance, Sep. 30	($	0.5	)	($	1.1	)	$	—		($	0.2	)
The amount of total losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at Sep. 30 (a)	$	—		($	0.6	)	$	—		$	—
WPL	Derivative Assets and (Liabilities), net
	Commodity Contracts						Foreign Contracts
Nine months ended Sep. 30	2011			2010			2011			2010
Beginning balance, Jan. 1	($	1.5	)	$	1.2		($	0.1	)	($	1.5	)
Total gains (losses) (realized/unrealized) included in changes in net assets (a)		(0.4	)		0.8			—			—
Transfers in and/or out of Level 3 (b)		0.2			(0.2	)		—			—
Purchases		3.7			—			—			—
Settlements		(2.5	)		(2.9	)		0.1			1.3
Ending balance, Sep. 30	($	0.5	)	($	1.1	)	$	—		($	0.2	)
The amount of total gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at Sep. 30 (a)	($	0.4	)	$	0.8		$	—		$	—

(a) Gains and losses related to derivative assets and liabilities are recorded in "Regulatory assets" and "Regulatory liabilities" on the Condensed Consolidated Balance Sheets.

(b) Observable market inputs became available for certain commodity contracts previously classified as Level 3. The transfers were valued as of the beginning of the period.

(c) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for doubtful accounts associated with the receivables sold and cash proceeds received from the receivables sold.

(d) The foreign exchange contract was transferred from IPL to Resources in connection with the sale of wind project assets in the second quarter of 2011.