Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2022

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Recurring Fair Value Measurements

Carrying amounts and the related estimated fair values of other financial instruments at December 31 were as follows (in millions):

Alliant Energy	2022					2021
		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	$10	$10	$—	$—	$10	$32	$32	$—	$—	$32
Derivatives	237	—	206	31	237	176	—	146	30	176
Deferred proceeds	185	—	—	185	185	214	—	—	214	214
Liabilities and equity:
Derivatives	79	—	67	12	79	9	—	8	1	9
Long-term debt (incl. current maturities)	8,076	—	7,338	1	7,339	7,368	—	8,329	1	8,330

IPL	2022					2021
		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	$10	$10	$—	$—	$10	$32	$32	$—	$—	$32
Derivatives	138	—	111	27	138	84	—	65	19	84
Deferred proceeds	185	—	—	185	185	214	—	—	214	214
Liabilities and equity:
Derivatives	46	—	35	11	46	4	—	3	1	4
Long-term debt	3,646	—	3,228	—	3,228	3,643	—	4,124	—	4,124

WPL	2022					2021
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Derivatives	$99	$—	$95	$4	$99	$92	$—	$81	$11	$92
Liabilities and equity:
Derivatives	33	—	32	1	33	5	—	5	—	5
Long-term debt (incl. current maturities)	2,770	—	2,542	—	2,542	2,429	—	2,862	—	2,862

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
	2022	2021	2022	2021
Beginning balance, January 1	$29	$29	$214	$188
Total net gains (losses) included in changes in net assets (realized/unrealized)	(18)	6	—	—
Purchases	79	21	—	—
Sales	(2)	(1)	—	—
Settlements (a)	(69)	(26)	(29)	26
Ending balance, December 31	$19	$29	$185	$214
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 December 31	($18)	$6	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
	2022	2021	2022	2021
Beginning balance, January 1	$18	$26	$214	$188
Total net losses included in changes in net assets (realized/unrealized)	(12)	(3)	—	—
Purchases	58	16	—	—
Sales	(1)	(1)	—	—
Settlements (a)	(47)	(20)	(29)	26
Ending balance, December 31	$16	$18	$185	$214
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 December 31	($13)	($3)	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
	2022	2021
Beginning balance, January 1	$11	$3
Total net gains (losses) included in changes in net assets (realized/unrealized)	(6)	9
Purchases	21	5
Sales	(1)	—
Settlements (a)	(22)	(6)
Ending balance, December 31	$3	$11
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 December 31	($5)	$9

(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) at December 31 as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
2022	($10)	$29	($9)	$25	($1)	$4
2021	9	20	8	10	1	10

IPL [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Recurring Fair Value Measurements

Carrying amounts and the related estimated fair values of other financial instruments at December 31 were as follows (in millions):

Alliant Energy	2022					2021
		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	$10	$10	$—	$—	$10	$32	$32	$—	$—	$32
Derivatives	237	—	206	31	237	176	—	146	30	176
Deferred proceeds	185	—	—	185	185	214	—	—	214	214
Liabilities and equity:
Derivatives	79	—	67	12	79	9	—	8	1	9
Long-term debt (incl. current maturities)	8,076	—	7,338	1	7,339	7,368	—	8,329	1	8,330

IPL	2022					2021
		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	$10	$10	$—	$—	$10	$32	$32	$—	$—	$32
Derivatives	138	—	111	27	138	84	—	65	19	84
Deferred proceeds	185	—	—	185	185	214	—	—	214	214
Liabilities and equity:
Derivatives	46	—	35	11	46	4	—	3	1	4
Long-term debt	3,646	—	3,228	—	3,228	3,643	—	4,124	—	4,124

WPL	2022					2021
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Derivatives	$99	$—	$95	$4	$99	$92	$—	$81	$11	$92
Liabilities and equity:
Derivatives	33	—	32	1	33	5	—	5	—	5
Long-term debt (incl. current maturities)	2,770	—	2,542	—	2,542	2,429	—	2,862	—	2,862

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
	2022	2021	2022	2021
Beginning balance, January 1	$29	$29	$214	$188
Total net gains (losses) included in changes in net assets (realized/unrealized)	(18)	6	—	—
Purchases	79	21	—	—
Sales	(2)	(1)	—	—
Settlements (a)	(69)	(26)	(29)	26
Ending balance, December 31	$19	$29	$185	$214
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 December 31	($18)	$6	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
	2022	2021	2022	2021
Beginning balance, January 1	$18	$26	$214	$188
Total net losses included in changes in net assets (realized/unrealized)	(12)	(3)	—	—
Purchases	58	16	—	—
Sales	(1)	(1)	—	—
Settlements (a)	(47)	(20)	(29)	26
Ending balance, December 31	$16	$18	$185	$214
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 December 31	($13)	($3)	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
	2022	2021
Beginning balance, January 1	$11	$3
Total net gains (losses) included in changes in net assets (realized/unrealized)	(6)	9
Purchases	21	5
Sales	(1)	—
Settlements (a)	(22)	(6)
Ending balance, December 31	$3	$11
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 December 31	($5)	$9

(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) at December 31 as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
2022	($10)	$29	($9)	$25	($1)	$4
2021	9	20	8	10	1	10

WPL [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Recurring Fair Value Measurements

Carrying amounts and the related estimated fair values of other financial instruments at December 31 were as follows (in millions):

Alliant Energy	2022					2021
		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	$10	$10	$—	$—	$10	$32	$32	$—	$—	$32
Derivatives	237	—	206	31	237	176	—	146	30	176
Deferred proceeds	185	—	—	185	185	214	—	—	214	214
Liabilities and equity:
Derivatives	79	—	67	12	79	9	—	8	1	9
Long-term debt (incl. current maturities)	8,076	—	7,338	1	7,339	7,368	—	8,329	1	8,330

IPL	2022					2021
		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	$10	$10	$—	$—	$10	$32	$32	$—	$—	$32
Derivatives	138	—	111	27	138	84	—	65	19	84
Deferred proceeds	185	—	—	185	185	214	—	—	214	214
Liabilities and equity:
Derivatives	46	—	35	11	46	4	—	3	1	4
Long-term debt	3,646	—	3,228	—	3,228	3,643	—	4,124	—	4,124

WPL	2022					2021
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Derivatives	$99	$—	$95	$4	$99	$92	$—	$81	$11	$92
Liabilities and equity:
Derivatives	33	—	32	1	33	5	—	5	—	5
Long-term debt (incl. current maturities)	2,770	—	2,542	—	2,542	2,429	—	2,862	—	2,862

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
	2022	2021	2022	2021
Beginning balance, January 1	$29	$29	$214	$188
Total net gains (losses) included in changes in net assets (realized/unrealized)	(18)	6	—	—
Purchases	79	21	—	—
Sales	(2)	(1)	—	—
Settlements (a)	(69)	(26)	(29)	26
Ending balance, December 31	$19	$29	$185	$214
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 December 31	($18)	$6	$—	$—

IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
	2022	2021	2022	2021
Beginning balance, January 1	$18	$26	$214	$188
Total net losses included in changes in net assets (realized/unrealized)	(12)	(3)	—	—
Purchases	58	16	—	—
Sales	(1)	(1)	—	—
Settlements (a)	(47)	(20)	(29)	26
Ending balance, December 31	$16	$18	$185	$214
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 December 31	($13)	($3)	$—	$—

WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
	2022	2021
Beginning balance, January 1	$11	$3
Total net gains (losses) included in changes in net assets (realized/unrealized)	(6)	9
Purchases	21	5
Sales	(1)	—
Settlements (a)	(22)	(6)
Ending balance, December 31	$3	$11
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 December 31	($5)	$9

(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) at December 31 as follows (in millions):

	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
2022	($10)	$29	($9)	$25	($1)	$4
2021	9	20	8	10	1	10