Regulatory Matters (Tables)

3 Months Ended

Mar. 31, 2023

Regulatory Assets [Line Items]

Regulatory Assets

Regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	March 31, 2023	December 31, 2022	March 31, 2023	December 31, 2022	March 31, 2023	December 31, 2022
Tax-related	$942	$929	$857	$848	$85	$81
Pension and OPEB costs	385	392	193	197	192	195
Asset retirement obligations	156	151	115	110	41	41
Commodity cost recovery	152	160	4	1	148	159
Derivatives	101	84	37	48	64	36
Assets retired early	67	70	51	53	16	17
IPL’s Duane Arnold Energy Center PPA amendment	60	66	60	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	48	48	—	—	48	48
Other	169	146	66	63	103	83
	$2,080	$2,046	$1,383	$1,386	$697	$660

Regulatory Liabilities

Regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	March 31, 2023	December 31, 2022	March 31, 2023	December 31, 2022	March 31, 2023	December 31, 2022
Tax-related	$575	$579	$302	$303	$273	$276
Cost of removal obligations	403	398	261	259	142	139
Derivatives	117	210	64	115	53	95
Electric transmission cost recovery	26	20	19	10	7	10
WPL’s West Riverside liquidated damages	24	32	—	—	24	32
Commodity cost recovery	22	40	8	38	14	2
Other	64	45	43	29	21	16
	$1,231	$1,324	$697	$754	$534	$570

IPL [Member]

Regulatory Assets [Line Items]

Regulatory Assets

Regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	March 31, 2023	December 31, 2022	March 31, 2023	December 31, 2022	March 31, 2023	December 31, 2022
Tax-related	$942	$929	$857	$848	$85	$81
Pension and OPEB costs	385	392	193	197	192	195
Asset retirement obligations	156	151	115	110	41	41
Commodity cost recovery	152	160	4	1	148	159
Derivatives	101	84	37	48	64	36
Assets retired early	67	70	51	53	16	17
IPL’s Duane Arnold Energy Center PPA amendment	60	66	60	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	48	48	—	—	48	48
Other	169	146	66	63	103	83
	$2,080	$2,046	$1,383	$1,386	$697	$660

Regulatory Liabilities

Regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	March 31, 2023	December 31, 2022	March 31, 2023	December 31, 2022	March 31, 2023	December 31, 2022
Tax-related	$575	$579	$302	$303	$273	$276
Cost of removal obligations	403	398	261	259	142	139
Derivatives	117	210	64	115	53	95
Electric transmission cost recovery	26	20	19	10	7	10
WPL’s West Riverside liquidated damages	24	32	—	—	24	32
Commodity cost recovery	22	40	8	38	14	2
Other	64	45	43	29	21	16
	$1,231	$1,324	$697	$754	$534	$570

WPL [Member]

Regulatory Assets [Line Items]

Regulatory Assets

Regulatory assets were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	March 31, 2023	December 31, 2022	March 31, 2023	December 31, 2022	March 31, 2023	December 31, 2022
Tax-related	$942	$929	$857	$848	$85	$81
Pension and OPEB costs	385	392	193	197	192	195
Asset retirement obligations	156	151	115	110	41	41
Commodity cost recovery	152	160	4	1	148	159
Derivatives	101	84	37	48	64	36
Assets retired early	67	70	51	53	16	17
IPL’s Duane Arnold Energy Center PPA amendment	60	66	60	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	48	48	—	—	48	48
Other	169	146	66	63	103	83
	$2,080	$2,046	$1,383	$1,386	$697	$660

Regulatory Liabilities

Regulatory liabilities were comprised of the following items (in millions):

	Alliant Energy		IPL		WPL
	March 31, 2023	December 31, 2022	March 31, 2023	December 31, 2022	March 31, 2023	December 31, 2022
Tax-related	$575	$579	$302	$303	$273	$276
Cost of removal obligations	403	398	261	259	142	139
Derivatives	117	210	64	115	53	95
Electric transmission cost recovery	26	20	19	10	7	10
WPL’s West Riverside liquidated damages	24	32	—	—	24	32
Commodity cost recovery	22	40	8	38	14	2
Other	64	45	43	29	21	16
	$1,231	$1,324	$697	$754	$534	$570