Fair Value Measurements

9 Months Ended

Sep. 30, 2019

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	September 30, 2019										December 31, 2018
			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		$174.4		$174.4		$—		$—		$174.4		$—		$—		$—		$—		$—
Derivatives	30.3		—		8.1		22.2		30.3		28.3		—		8.9		19.4		28.3
Deferred proceeds	237.0		—		—		237.0		237.0		119.4		—		—		119.4		119.4
Liabilities:
Derivatives	31.8		—		31.3		0.5		31.8		23.3		—		16.1		7.2		23.3
Long-term debt (incl. current maturities)	6,191.9		—		7,016.4		2.0		7,018.4		5,502.8		—		5,858.4		2.4		5,860.8

IPL	September 30, 2019										December 31, 2018
			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		$173.7		$173.7		$—		$—		$173.7		$—		$—		$—		$—		$—
Derivatives	23.3		—		4.8		18.5		23.3		17.7		—		4.0		13.7		17.7
Deferred proceeds	237.0		—		—		237.0		237.0		119.4		—		—		119.4		119.4
Liabilities:
Derivatives	13.4		—		12.9		0.5		13.4		11.2		—		6.5		4.7		11.2
Long-term debt (incl. current maturities)	3,146.8		—		3,537.0		—		3,537.0		2,552.3		—		2,691.2		—		2,691.2

WPL	September 30, 2019										December 31, 2018
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Derivatives		$7.0		$—		$3.3		$3.7		$7.0		$10.6		$—		$4.9		$5.7		$10.6
Liabilities:
Derivatives	18.4		—		18.4		—		18.4		12.1		—		9.6		2.5		12.1
Long-term debt (incl. current maturities)	1,932.3		—		2,314.1		—		2,314.1		1,834.9		—		2,043.7		—		2,043.7

Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions):

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2019			2018			2019		2018
Beginning balance, July 1		$13.2			($10.7	)		$214.6		$208.3
Total net gains included in changes in net assets (realized/unrealized)	12.7			25.7			—		—
Transfers out of Level 3	(1.2		)	15.6			—		—
Sales	—			(0.2		)	—		—
Settlements (a)	(3.0		)	(6.2		)	22.4		35.4
Ending balance, September 30		$21.7			$24.2			$237.0		$243.7
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 September 30		$12.7			$26.1			$—		$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2019			2018			2019		2018
Beginning balance, January 1		$12.2			($12.2	)		$119.4		$222.1
Total net gains included in changes in net assets (realized/unrealized)	6.9			15.7			—		—
Transfers out of Level 3	2.8			15.6			—		—
Purchases	13.8			26.7			—		—
Sales	(0.2		)	(0.2		)	—		—
Settlements (a)	(13.8		)	(21.4		)	117.6		21.6
Ending balance, September 30		$21.7			$24.2			$237.0		$243.7
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 September 30		$10.1			$16.5			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2019			2018			2019		2018
Beginning balance, July 1		$9.3			($4.1	)		$214.6		$208.3
Total net gains included in changes in net assets (realized/unrealized)	11.5			16.8			—		—
Transfers out of Level 3	(0.6		)	10.5			—		—
Sales	—			(0.1		)	—		—
Settlements (a)	(2.2		)	(4.9		)	22.4		35.4
Ending balance, September 30		$18.0			$18.2			$237.0		$243.7
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 September 30		$11.5			$16.8			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2019			2018			2019		2018
Beginning balance, January 1		$9.0			($1.4	)		$119.4		$222.1
Total net gains included in changes in net assets (realized/unrealized)	8.6			7.6			—		—
Transfers out of Level 3	2.0			10.5			—		—
Purchases	9.5			19.3			—		—
Sales	(0.1		)	(0.1		)	—		—
Settlements (a)	(11.0		)	(17.7		)	117.6		21.6
Ending balance, September 30		$18.0			$18.2			$237.0		$243.7
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 September 30		$10.5			$7.9			$—		$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Three Months Ended September 30	2019			2018
Beginning balance, July 1		$3.9			($6.6	)
Total net gains included in changes in net assets (realized/unrealized)	1.2			8.9
Transfers out of Level 3	(0.6		)	5.1
Sales	—			(0.1		)
Settlements	(0.8		)	(1.3		)
Ending balance, September 30		$3.7			$6.0
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 September 30		$1.2			$9.3

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Nine Months Ended September 30	2019			2018
Beginning balance, January 1		$3.2			($10.8	)
Total net gains (losses) included in changes in net assets (realized/unrealized)	(1.7		)	8.1
Transfers out of Level 3	0.8			5.1
Purchases	4.3			7.4
Sales	(0.1		)	(0.1		)
Settlements	(2.8		)	(3.7		)
Ending balance, September 30		$3.7			$6.0
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 September 30		($0.4	)		$8.6

(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
September 30, 2019		$13.1		$8.6		$12.5		$5.5		$0.6		$3.1
December 31, 2018	3.2		9.0		1.8		7.2		1.4		1.8

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	September 30, 2019										December 31, 2018
			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		$174.4		$174.4		$—		$—		$174.4		$—		$—		$—		$—		$—
Derivatives	30.3		—		8.1		22.2		30.3		28.3		—		8.9		19.4		28.3
Deferred proceeds	237.0		—		—		237.0		237.0		119.4		—		—		119.4		119.4
Liabilities:
Derivatives	31.8		—		31.3		0.5		31.8		23.3		—		16.1		7.2		23.3
Long-term debt (incl. current maturities)	6,191.9		—		7,016.4		2.0		7,018.4		5,502.8		—		5,858.4		2.4		5,860.8

IPL	September 30, 2019										December 31, 2018
			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		$173.7		$173.7		$—		$—		$173.7		$—		$—		$—		$—		$—
Derivatives	23.3		—		4.8		18.5		23.3		17.7		—		4.0		13.7		17.7
Deferred proceeds	237.0		—		—		237.0		237.0		119.4		—		—		119.4		119.4
Liabilities:
Derivatives	13.4		—		12.9		0.5		13.4		11.2		—		6.5		4.7		11.2
Long-term debt (incl. current maturities)	3,146.8		—		3,537.0		—		3,537.0		2,552.3		—		2,691.2		—		2,691.2

WPL	September 30, 2019										December 31, 2018
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Derivatives		$7.0		$—		$3.3		$3.7		$7.0		$10.6		$—		$4.9		$5.7		$10.6
Liabilities:
Derivatives	18.4		—		18.4		—		18.4		12.1		—		9.6		2.5		12.1
Long-term debt (incl. current maturities)	1,932.3		—		2,314.1		—		2,314.1		1,834.9		—		2,043.7		—		2,043.7

Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions):

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2019			2018			2019		2018
Beginning balance, July 1		$13.2			($10.7	)		$214.6		$208.3
Total net gains included in changes in net assets (realized/unrealized)	12.7			25.7			—		—
Transfers out of Level 3	(1.2		)	15.6			—		—
Sales	—			(0.2		)	—		—
Settlements (a)	(3.0		)	(6.2		)	22.4		35.4
Ending balance, September 30		$21.7			$24.2			$237.0		$243.7
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 September 30		$12.7			$26.1			$—		$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2019			2018			2019		2018
Beginning balance, January 1		$12.2			($12.2	)		$119.4		$222.1
Total net gains included in changes in net assets (realized/unrealized)	6.9			15.7			—		—
Transfers out of Level 3	2.8			15.6			—		—
Purchases	13.8			26.7			—		—
Sales	(0.2		)	(0.2		)	—		—
Settlements (a)	(13.8		)	(21.4		)	117.6		21.6
Ending balance, September 30		$21.7			$24.2			$237.0		$243.7
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 September 30		$10.1			$16.5			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2019			2018			2019		2018
Beginning balance, July 1		$9.3			($4.1	)		$214.6		$208.3
Total net gains included in changes in net assets (realized/unrealized)	11.5			16.8			—		—
Transfers out of Level 3	(0.6		)	10.5			—		—
Sales	—			(0.1		)	—		—
Settlements (a)	(2.2		)	(4.9		)	22.4		35.4
Ending balance, September 30		$18.0			$18.2			$237.0		$243.7
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 September 30		$11.5			$16.8			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2019			2018			2019		2018
Beginning balance, January 1		$9.0			($1.4	)		$119.4		$222.1
Total net gains included in changes in net assets (realized/unrealized)	8.6			7.6			—		—
Transfers out of Level 3	2.0			10.5			—		—
Purchases	9.5			19.3			—		—
Sales	(0.1		)	(0.1		)	—		—
Settlements (a)	(11.0		)	(17.7		)	117.6		21.6
Ending balance, September 30		$18.0			$18.2			$237.0		$243.7
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 September 30		$10.5			$7.9			$—		$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Three Months Ended September 30	2019			2018
Beginning balance, July 1		$3.9			($6.6	)
Total net gains included in changes in net assets (realized/unrealized)	1.2			8.9
Transfers out of Level 3	(0.6		)	5.1
Sales	—			(0.1		)
Settlements	(0.8		)	(1.3		)
Ending balance, September 30		$3.7			$6.0
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 September 30		$1.2			$9.3

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Nine Months Ended September 30	2019			2018
Beginning balance, January 1		$3.2			($10.8	)
Total net gains (losses) included in changes in net assets (realized/unrealized)	(1.7		)	8.1
Transfers out of Level 3	0.8			5.1
Purchases	4.3			7.4
Sales	(0.1		)	(0.1		)
Settlements	(2.8		)	(3.7		)
Ending balance, September 30		$3.7			$6.0
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 September 30		($0.4	)		$8.6

(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
September 30, 2019		$13.1		$8.6		$12.5		$5.5		$0.6		$3.1
December 31, 2018	3.2		9.0		1.8		7.2		1.4		1.8

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	September 30, 2019										December 31, 2018
			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		$174.4		$174.4		$—		$—		$174.4		$—		$—		$—		$—		$—
Derivatives	30.3		—		8.1		22.2		30.3		28.3		—		8.9		19.4		28.3
Deferred proceeds	237.0		—		—		237.0		237.0		119.4		—		—		119.4		119.4
Liabilities:
Derivatives	31.8		—		31.3		0.5		31.8		23.3		—		16.1		7.2		23.3
Long-term debt (incl. current maturities)	6,191.9		—		7,016.4		2.0		7,018.4		5,502.8		—		5,858.4		2.4		5,860.8

IPL	September 30, 2019										December 31, 2018
			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		$173.7		$173.7		$—		$—		$173.7		$—		$—		$—		$—		$—
Derivatives	23.3		—		4.8		18.5		23.3		17.7		—		4.0		13.7		17.7
Deferred proceeds	237.0		—		—		237.0		237.0		119.4		—		—		119.4		119.4
Liabilities:
Derivatives	13.4		—		12.9		0.5		13.4		11.2		—		6.5		4.7		11.2
Long-term debt (incl. current maturities)	3,146.8		—		3,537.0		—		3,537.0		2,552.3		—		2,691.2		—		2,691.2

WPL	September 30, 2019										December 31, 2018
			Fair Value										Fair Value
	Carrying		Level		Level		Level				Carrying		Level		Level		Level
	Amount		1		2		3		Total		Amount		1		2		3		Total
Assets:
Derivatives		$7.0		$—		$3.3		$3.7		$7.0		$10.6		$—		$4.9		$5.7		$10.6
Liabilities:
Derivatives	18.4		—		18.4		—		18.4		12.1		—		9.6		2.5		12.1
Long-term debt (incl. current maturities)	1,932.3		—		2,314.1		—		2,314.1		1,834.9		—		2,043.7		—		2,043.7

Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions):

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2019			2018			2019		2018
Beginning balance, July 1		$13.2			($10.7	)		$214.6		$208.3
Total net gains included in changes in net assets (realized/unrealized)	12.7			25.7			—		—
Transfers out of Level 3	(1.2		)	15.6			—		—
Sales	—			(0.2		)	—		—
Settlements (a)	(3.0		)	(6.2		)	22.4		35.4
Ending balance, September 30		$21.7			$24.2			$237.0		$243.7
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 September 30		$12.7			$26.1			$—		$—

Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2019			2018			2019		2018
Beginning balance, January 1		$12.2			($12.2	)		$119.4		$222.1
Total net gains included in changes in net assets (realized/unrealized)	6.9			15.7			—		—
Transfers out of Level 3	2.8			15.6			—		—
Purchases	13.8			26.7			—		—
Sales	(0.2		)	(0.2		)	—		—
Settlements (a)	(13.8		)	(21.4		)	117.6		21.6
Ending balance, September 30		$21.7			$24.2			$237.0		$243.7
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 September 30		$10.1			$16.5			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Three Months Ended September 30	2019			2018			2019		2018
Beginning balance, July 1		$9.3			($4.1	)		$214.6		$208.3
Total net gains included in changes in net assets (realized/unrealized)	11.5			16.8			—		—
Transfers out of Level 3	(0.6		)	10.5			—		—
Sales	—			(0.1		)	—		—
Settlements (a)	(2.2		)	(4.9		)	22.4		35.4
Ending balance, September 30		$18.0			$18.2			$237.0		$243.7
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 September 30		$11.5			$16.8			$—		$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net						Deferred Proceeds
Nine Months Ended September 30	2019			2018			2019		2018
Beginning balance, January 1		$9.0			($1.4	)		$119.4		$222.1
Total net gains included in changes in net assets (realized/unrealized)	8.6			7.6			—		—
Transfers out of Level 3	2.0			10.5			—		—
Purchases	9.5			19.3			—		—
Sales	(0.1		)	(0.1		)	—		—
Settlements (a)	(11.0		)	(17.7		)	117.6		21.6
Ending balance, September 30		$18.0			$18.2			$237.0		$243.7
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 September 30		$10.5			$7.9			$—		$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Three Months Ended September 30	2019			2018
Beginning balance, July 1		$3.9			($6.6	)
Total net gains included in changes in net assets (realized/unrealized)	1.2			8.9
Transfers out of Level 3	(0.6		)	5.1
Sales	—			(0.1		)
Settlements	(0.8		)	(1.3		)
Ending balance, September 30		$3.7			$6.0
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 September 30		$1.2			$9.3

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Nine Months Ended September 30	2019			2018
Beginning balance, January 1		$3.2			($10.8	)
Total net gains (losses) included in changes in net assets (realized/unrealized)	(1.7		)	8.1
Transfers out of Level 3	0.8			5.1
Purchases	4.3			7.4
Sales	(0.1		)	(0.1		)
Settlements	(2.8		)	(3.7		)
Ending balance, September 30		$3.7			$6.0
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 September 30		($0.4	)		$8.6

(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
September 30, 2019		$13.1		$8.6		$12.5		$5.5		$0.6		$3.1
December 31, 2018	3.2		9.0		1.8		7.2		1.4		1.8