Fair Value Measurements

6 Months Ended

Jun. 30, 2020

Fair Value Measurements

FAIR VALUE MEASUREMENTS

Fair Value of Financial Instruments - The carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions):

Alliant Energy	June 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Money market fund investments		$198.3		$198.3		$—		$—		$198.3		$5.4		$5.4		$—		$—		$5.4
Derivatives	42.4		—		4.6		37.8		42.4		26.8		—		4.8		22.0		26.8
Deferred proceeds	194.1		—		—		194.1		194.1		187.7		—		—		187.7		187.7
Liabilities:
Derivatives	46.2		—		44.8		1.4		46.2		37.6		—		36.8		0.8		37.6
Long-term debt (incl. current maturities)	6,579.8		—		7,768.1		1.7		7,769.8		6,190.2		—		6,917.9		2.0		6,919.9

IPL	June 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Money market fund investments		$198.3		$198.3		$—		$—		$198.3		$5.4		$5.4		$—		$—		$5.4
Derivatives	37.0		—		3.3		33.7		37.0		22.3		—		2.8		19.5		22.3
Deferred proceeds	194.1		—		—		194.1		194.1		187.7		—		—		187.7		187.7
Liabilities:
Derivatives	20.3		—		19.0		1.3		20.3		17.4		—		16.6		0.8		17.4
Long-term debt (incl. current maturities)	3,343.5		—		3,924.7		—		3,924.7		3,147.3		—		3,489.1		—		3,489.1

WPL	June 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Derivatives		$5.4		$—		$1.3		$4.1		$5.4		$4.5		$—		$2.0		$2.5		$4.5
Liabilities:
Derivatives	25.9		—		25.8		0.1		25.9		20.2		—		20.2		—		20.2
Long-term debt (incl. current maturities)	2,129.4		—		2,657.2		—		2,657.2		1,932.7		—		2,268.2		—		2,268.2

Information for Alliant Energy’s and IPL’s fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions). Such amounts for WPL were not material.

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended June 30	2020			2019			2020		2019
Beginning balance, April 1		$14.2			$0.4			$188.0		$178.3
Total net gains (losses) included in changes in net assets (realized/unrealized)	12.0			(0.1		)	—		—
Transfers out of Level 3	—			3.9			—		—
Purchases	14.0			13.8			—		—
Sales	(0.1		)	—			—		—
Settlements (a)	(3.7		)	(4.8		)	6.1		36.3
Ending balance, June 30		$36.4			$13.2			$194.1		$214.6
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at June 30		$11.9			$—			$—		$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Six Months Ended June 30	2020			2019			2020		2019
Beginning balance, January 1		$21.2			$12.2			$187.7		$119.4
Total net gains (losses) included in changes in net assets (realized/unrealized)	9.0			(5.7		)	—		—
Transfers out of Level 3	—			3.9			—		—
Purchases	14.0			13.8			—		—
Sales	(0.2		)	(0.2		)	—		—
Settlements (a)	(7.6		)	(10.8		)	6.4		95.2
Ending balance, June 30		$36.4			$13.2			$194.1		$214.6
The amount of total net 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 June 30		$9.0			($2.6	)		$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended June 30	2020			2019			2020		2019
Beginning balance, April 1		$13.5			$0.6			$188.0		$178.3
Total net gains included in changes in net assets (realized/unrealized)	11.0			0.4			—		—
Transfers out of Level 3	—			2.5			—		—
Purchases	10.7			9.5			—		—
Sales	(0.1		)	—			—		—
Settlements (a)	(2.7		)	(3.7		)	6.1		36.3
Ending balance, June 30		$32.4			$9.3			$194.1		$214.6
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at June 30		$11.0			$0.5			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Six Months Ended June 30	2020			2019			2020		2019
Beginning balance, January 1		$18.7			$9.0			$187.7		$119.4
Total net gains (losses) included in changes in net assets (realized/unrealized)	8.8			(2.8		)	—		—
Transfers out of Level 3	—			2.5			—		—
Purchases	10.7			9.5			—		—
Sales	(0.2		)	(0.1		)	—		—
Settlements (a)	(5.6		)	(8.8		)	6.4		95.2
Ending balance, June 30		$32.4			$9.3			$194.1		$214.6
The amount of total net 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 June 30		$8.8			($0.9	)		$—		$—

(a) 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 amounts received from the receivables sold.

Commodity Contracts - The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets as follows (in millions):

	Alliant Energy				IPL				WPL
	Excluding FTRs		FTRs		Excluding FTRs		FTRs		Excluding FTRs		FTRs
June 30, 2020		$19.3		$17.1		$18.6		$13.8		$0.7		$3.3
December 31, 2019	14.6		6.6		13.6		5.1		1.0		1.5

IPL [Member]

Fair Value Measurements

FAIR VALUE MEASUREMENTS

Fair Value of Financial Instruments - The carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions):

Alliant Energy	June 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Money market fund investments		$198.3		$198.3		$—		$—		$198.3		$5.4		$5.4		$—		$—		$5.4
Derivatives	42.4		—		4.6		37.8		42.4		26.8		—		4.8		22.0		26.8
Deferred proceeds	194.1		—		—		194.1		194.1		187.7		—		—		187.7		187.7
Liabilities:
Derivatives	46.2		—		44.8		1.4		46.2		37.6		—		36.8		0.8		37.6
Long-term debt (incl. current maturities)	6,579.8		—		7,768.1		1.7		7,769.8		6,190.2		—		6,917.9		2.0		6,919.9

IPL	June 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Money market fund investments		$198.3		$198.3		$—		$—		$198.3		$5.4		$5.4		$—		$—		$5.4
Derivatives	37.0		—		3.3		33.7		37.0		22.3		—		2.8		19.5		22.3
Deferred proceeds	194.1		—		—		194.1		194.1		187.7		—		—		187.7		187.7
Liabilities:
Derivatives	20.3		—		19.0		1.3		20.3		17.4		—		16.6		0.8		17.4
Long-term debt (incl. current maturities)	3,343.5		—		3,924.7		—		3,924.7		3,147.3		—		3,489.1		—		3,489.1

WPL	June 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Derivatives		$5.4		$—		$1.3		$4.1		$5.4		$4.5		$—		$2.0		$2.5		$4.5
Liabilities:
Derivatives	25.9		—		25.8		0.1		25.9		20.2		—		20.2		—		20.2
Long-term debt (incl. current maturities)	2,129.4		—		2,657.2		—		2,657.2		1,932.7		—		2,268.2		—		2,268.2

Information for Alliant Energy’s and IPL’s fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions). Such amounts for WPL were not material.

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended June 30	2020			2019			2020		2019
Beginning balance, April 1		$14.2			$0.4			$188.0		$178.3
Total net gains (losses) included in changes in net assets (realized/unrealized)	12.0			(0.1		)	—		—
Transfers out of Level 3	—			3.9			—		—
Purchases	14.0			13.8			—		—
Sales	(0.1		)	—			—		—
Settlements (a)	(3.7		)	(4.8		)	6.1		36.3
Ending balance, June 30		$36.4			$13.2			$194.1		$214.6
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at June 30		$11.9			$—			$—		$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Six Months Ended June 30	2020			2019			2020		2019
Beginning balance, January 1		$21.2			$12.2			$187.7		$119.4
Total net gains (losses) included in changes in net assets (realized/unrealized)	9.0			(5.7		)	—		—
Transfers out of Level 3	—			3.9			—		—
Purchases	14.0			13.8			—		—
Sales	(0.2		)	(0.2		)	—		—
Settlements (a)	(7.6		)	(10.8		)	6.4		95.2
Ending balance, June 30		$36.4			$13.2			$194.1		$214.6
The amount of total net 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 June 30		$9.0			($2.6	)		$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended June 30	2020			2019			2020		2019
Beginning balance, April 1		$13.5			$0.6			$188.0		$178.3
Total net gains included in changes in net assets (realized/unrealized)	11.0			0.4			—		—
Transfers out of Level 3	—			2.5			—		—
Purchases	10.7			9.5			—		—
Sales	(0.1		)	—			—		—
Settlements (a)	(2.7		)	(3.7		)	6.1		36.3
Ending balance, June 30		$32.4			$9.3			$194.1		$214.6
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at June 30		$11.0			$0.5			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Six Months Ended June 30	2020			2019			2020		2019
Beginning balance, January 1		$18.7			$9.0			$187.7		$119.4
Total net gains (losses) included in changes in net assets (realized/unrealized)	8.8			(2.8		)	—		—
Transfers out of Level 3	—			2.5			—		—
Purchases	10.7			9.5			—		—
Sales	(0.2		)	(0.1		)	—		—
Settlements (a)	(5.6		)	(8.8		)	6.4		95.2
Ending balance, June 30		$32.4			$9.3			$194.1		$214.6
The amount of total net 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 June 30		$8.8			($0.9	)		$—		$—

(a) 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 amounts received from the receivables sold.

Commodity Contracts - The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets as follows (in millions):

	Alliant Energy				IPL				WPL
	Excluding FTRs		FTRs		Excluding FTRs		FTRs		Excluding FTRs		FTRs
June 30, 2020		$19.3		$17.1		$18.6		$13.8		$0.7		$3.3
December 31, 2019	14.6		6.6		13.6		5.1		1.0		1.5

WPL [Member]

Fair Value Measurements

FAIR VALUE MEASUREMENTS

Fair Value of Financial Instruments - The carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions):

Alliant Energy	June 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Money market fund investments		$198.3		$198.3		$—		$—		$198.3		$5.4		$5.4		$—		$—		$5.4
Derivatives	42.4		—		4.6		37.8		42.4		26.8		—		4.8		22.0		26.8
Deferred proceeds	194.1		—		—		194.1		194.1		187.7		—		—		187.7		187.7
Liabilities:
Derivatives	46.2		—		44.8		1.4		46.2		37.6		—		36.8		0.8		37.6
Long-term debt (incl. current maturities)	6,579.8		—		7,768.1		1.7		7,769.8		6,190.2		—		6,917.9		2.0		6,919.9

IPL	June 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Money market fund investments		$198.3		$198.3		$—		$—		$198.3		$5.4		$5.4		$—		$—		$5.4
Derivatives	37.0		—		3.3		33.7		37.0		22.3		—		2.8		19.5		22.3
Deferred proceeds	194.1		—		—		194.1		194.1		187.7		—		—		187.7		187.7
Liabilities:
Derivatives	20.3		—		19.0		1.3		20.3		17.4		—		16.6		0.8		17.4
Long-term debt (incl. current maturities)	3,343.5		—		3,924.7		—		3,924.7		3,147.3		—		3,489.1		—		3,489.1

WPL	June 30, 2020										December 31, 2019
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Derivatives		$5.4		$—		$1.3		$4.1		$5.4		$4.5		$—		$2.0		$2.5		$4.5
Liabilities:
Derivatives	25.9		—		25.8		0.1		25.9		20.2		—		20.2		—		20.2
Long-term debt (incl. current maturities)	2,129.4		—		2,657.2		—		2,657.2		1,932.7		—		2,268.2		—		2,268.2

Information for Alliant Energy’s and IPL’s fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions). Such amounts for WPL were not material.

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended June 30	2020			2019			2020		2019
Beginning balance, April 1		$14.2			$0.4			$188.0		$178.3
Total net gains (losses) included in changes in net assets (realized/unrealized)	12.0			(0.1		)	—		—
Transfers out of Level 3	—			3.9			—		—
Purchases	14.0			13.8			—		—
Sales	(0.1		)	—			—		—
Settlements (a)	(3.7		)	(4.8		)	6.1		36.3
Ending balance, June 30		$36.4			$13.2			$194.1		$214.6
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at June 30		$11.9			$—			$—		$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Six Months Ended June 30	2020			2019			2020		2019
Beginning balance, January 1		$21.2			$12.2			$187.7		$119.4
Total net gains (losses) included in changes in net assets (realized/unrealized)	9.0			(5.7		)	—		—
Transfers out of Level 3	—			3.9			—		—
Purchases	14.0			13.8			—		—
Sales	(0.2		)	(0.2		)	—		—
Settlements (a)	(7.6		)	(10.8		)	6.4		95.2
Ending balance, June 30		$36.4			$13.2			$194.1		$214.6
The amount of total net 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 June 30		$9.0			($2.6	)		$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended June 30	2020			2019			2020		2019
Beginning balance, April 1		$13.5			$0.6			$188.0		$178.3
Total net gains included in changes in net assets (realized/unrealized)	11.0			0.4			—		—
Transfers out of Level 3	—			2.5			—		—
Purchases	10.7			9.5			—		—
Sales	(0.1		)	—			—		—
Settlements (a)	(2.7		)	(3.7		)	6.1		36.3
Ending balance, June 30		$32.4			$9.3			$194.1		$214.6
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at June 30		$11.0			$0.5			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Six Months Ended June 30	2020			2019			2020		2019
Beginning balance, January 1		$18.7			$9.0			$187.7		$119.4
Total net gains (losses) included in changes in net assets (realized/unrealized)	8.8			(2.8		)	—		—
Transfers out of Level 3	—			2.5			—		—
Purchases	10.7			9.5			—		—
Sales	(0.2		)	(0.1		)	—		—
Settlements (a)	(5.6		)	(8.8		)	6.4		95.2
Ending balance, June 30		$32.4			$9.3			$194.1		$214.6
The amount of total net 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 June 30		$8.8			($0.9	)		$—		$—

(a) 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 amounts received from the receivables sold.

Commodity Contracts - The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets as follows (in millions):

	Alliant Energy				IPL				WPL
	Excluding FTRs		FTRs		Excluding FTRs		FTRs		Excluding FTRs		FTRs
June 30, 2020		$19.3		$17.1		$18.6		$13.8		$0.7		$3.3
December 31, 2019	14.6		6.6		13.6		5.1		1.0		1.5