Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2023

Statement [Line Items]

Fair Value Measurements

Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions):

Alliant Energy	March 31, 2023					December 31, 2022
		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	$148	$148	$—	$—	$148	$10	$10	$—	$—	$10
Commodity derivatives	122	—	116	6	122	237	—	206	31	237
Deferred proceeds	153	—	—	153	153	185	—	—	185	185
Liabilities:
Commodity derivatives	95	—	84	11	95	79	—	67	12	79
Interest rate derivatives	1	—	1	—	1	—	—	—	—	—
Long-term debt (incl. current maturities)	8,940	—	8,461	1	8,462	8,076	—	7,338	1	7,339

IPL	March 31, 2023					December 31, 2022
		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	$30	$30	$—	$—	$30	$10	$10	$—	$—	$10
Commodity derivatives	69	—	63	6	69	138	—	111	27	138
Deferred proceeds	153	—	—	153	153	185	—	—	185	185
Liabilities:
Commodity derivatives	34	—	28	6	34	46	—	35	11	46
Long-term debt	3,647	—	3,335	—	3,335	3,646	—	3,228	—	3,228

WPL	March 31, 2023					December 31, 2022
		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	$83	$83	$—	$—	$83	$—	$—	$—	$—	$—
Commodity derivatives	53	—	53	—	53	99	—	95	4	99
Liabilities:
Commodity derivatives	61	—	56	5	61	33	—	32	1	33
Long-term debt	3,067	—	2,939	—	2,939	2,770	—	2,542	—	2,542

Fair Value Measurements Using Significant Unobservable Inputs

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 March 31	2023	2022	2023	2022
Beginning balance, January 1	$19	$29	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(4)	(6)	—	—
Settlements (a)	(20)	(13)	(32)	13
Ending balance, March 31	($5)	$10	$153	$227
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at March 31	($4)	($5)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Three Months Ended March 31	2023	2022	2023	2022
Beginning balance, January 1	$16	$18	$185	$214
Total net gains (losses) included in changes in net assets (realized/unrealized)	1	(4)	—	—
Settlements (a)	(17)	(7)	(32)	13
Ending balance, March 31	$—	$7	$153	$227
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 March 31	$1	($4)	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Three Months Ended March 31	2023	2022
Beginning balance, January 1	$3	$11
Total net losses included in changes in net assets (realized/unrealized)	(5)	(2)
Settlements	(3)	(6)
Ending balance, March 31	($5)	$3
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at March 31	($5)	($1)

(a)Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold.

Fair Value Of Net Derivative Assets (Liabilities)

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

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
March 31, 2023	($10)	$5	($4)	$4	($6)	$1
December 31, 2022	(10)	29	(9)	25	(1)	4

IPL [Member]

Statement [Line Items]

Fair Value Measurements

Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions):

Alliant Energy	March 31, 2023					December 31, 2022
		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	$148	$148	$—	$—	$148	$10	$10	$—	$—	$10
Commodity derivatives	122	—	116	6	122	237	—	206	31	237
Deferred proceeds	153	—	—	153	153	185	—	—	185	185
Liabilities:
Commodity derivatives	95	—	84	11	95	79	—	67	12	79
Interest rate derivatives	1	—	1	—	1	—	—	—	—	—
Long-term debt (incl. current maturities)	8,940	—	8,461	1	8,462	8,076	—	7,338	1	7,339

IPL	March 31, 2023					December 31, 2022
		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	$30	$30	$—	$—	$30	$10	$10	$—	$—	$10
Commodity derivatives	69	—	63	6	69	138	—	111	27	138
Deferred proceeds	153	—	—	153	153	185	—	—	185	185
Liabilities:
Commodity derivatives	34	—	28	6	34	46	—	35	11	46
Long-term debt	3,647	—	3,335	—	3,335	3,646	—	3,228	—	3,228

WPL	March 31, 2023					December 31, 2022
		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	$83	$83	$—	$—	$83	$—	$—	$—	$—	$—
Commodity derivatives	53	—	53	—	53	99	—	95	4	99
Liabilities:
Commodity derivatives	61	—	56	5	61	33	—	32	1	33
Long-term debt	3,067	—	2,939	—	2,939	2,770	—	2,542	—	2,542

Fair Value Measurements Using Significant Unobservable Inputs

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 March 31	2023	2022	2023	2022
Beginning balance, January 1	$19	$29	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(4)	(6)	—	—
Settlements (a)	(20)	(13)	(32)	13
Ending balance, March 31	($5)	$10	$153	$227
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at March 31	($4)	($5)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Three Months Ended March 31	2023	2022	2023	2022
Beginning balance, January 1	$16	$18	$185	$214
Total net gains (losses) included in changes in net assets (realized/unrealized)	1	(4)	—	—
Settlements (a)	(17)	(7)	(32)	13
Ending balance, March 31	$—	$7	$153	$227
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 March 31	$1	($4)	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Three Months Ended March 31	2023	2022
Beginning balance, January 1	$3	$11
Total net losses included in changes in net assets (realized/unrealized)	(5)	(2)
Settlements	(3)	(6)
Ending balance, March 31	($5)	$3
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at March 31	($5)	($1)

(a)Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold.

Fair Value Of Net Derivative Assets (Liabilities)

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

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
March 31, 2023	($10)	$5	($4)	$4	($6)	$1
December 31, 2022	(10)	29	(9)	25	(1)	4

WPL [Member]

Statement [Line Items]

Fair Value Measurements

Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions):

Alliant Energy	March 31, 2023					December 31, 2022
		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	$148	$148	$—	$—	$148	$10	$10	$—	$—	$10
Commodity derivatives	122	—	116	6	122	237	—	206	31	237
Deferred proceeds	153	—	—	153	153	185	—	—	185	185
Liabilities:
Commodity derivatives	95	—	84	11	95	79	—	67	12	79
Interest rate derivatives	1	—	1	—	1	—	—	—	—	—
Long-term debt (incl. current maturities)	8,940	—	8,461	1	8,462	8,076	—	7,338	1	7,339

IPL	March 31, 2023					December 31, 2022
		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	$30	$30	$—	$—	$30	$10	$10	$—	$—	$10
Commodity derivatives	69	—	63	6	69	138	—	111	27	138
Deferred proceeds	153	—	—	153	153	185	—	—	185	185
Liabilities:
Commodity derivatives	34	—	28	6	34	46	—	35	11	46
Long-term debt	3,647	—	3,335	—	3,335	3,646	—	3,228	—	3,228

WPL	March 31, 2023					December 31, 2022
		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	$83	$83	$—	$—	$83	$—	$—	$—	$—	$—
Commodity derivatives	53	—	53	—	53	99	—	95	4	99
Liabilities:
Commodity derivatives	61	—	56	5	61	33	—	32	1	33
Long-term debt	3,067	—	2,939	—	2,939	2,770	—	2,542	—	2,542

Fair Value Measurements Using Significant Unobservable Inputs

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 March 31	2023	2022	2023	2022
Beginning balance, January 1	$19	$29	$185	$214
Total net losses included in changes in net assets (realized/unrealized)	(4)	(6)	—	—
Settlements (a)	(20)	(13)	(32)	13
Ending balance, March 31	($5)	$10	$153	$227
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at March 31	($4)	($5)	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Three Months Ended March 31	2023	2022	2023	2022
Beginning balance, January 1	$16	$18	$185	$214
Total net gains (losses) included in changes in net assets (realized/unrealized)	1	(4)	—	—
Settlements (a)	(17)	(7)	(32)	13
Ending balance, March 31	$—	$7	$153	$227
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 March 31	$1	($4)	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Three Months Ended March 31	2023	2022
Beginning balance, January 1	$3	$11
Total net losses included in changes in net assets (realized/unrealized)	(5)	(2)
Settlements	(3)	(6)
Ending balance, March 31	($5)	$3
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at March 31	($5)	($1)

(a)Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold.

Fair Value Of Net Derivative Assets (Liabilities)

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

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
March 31, 2023	($10)	$5	($4)	$4	($6)	$1
December 31, 2022	(10)	29	(9)	25	(1)	4