Regulatory Matters (Tables)

6 Months Ended

Jun. 30, 2024

Regulatory Assets [Line Items]

Regulatory Assets

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

	Alliant Energy		IPL		WPL
	June 30, 2024	December 31, 2023	June 30, 2024	December 31, 2023	June 30, 2024	December 31, 2023
Tax-related	$958	$934	$848	$831	$110	$103
AROs	408	194	218	160	190	34
Pension and OPEB costs	334	347	165	171	169	176
Assets retired early	197	273	184	259	13	14
Derivatives	95	102	33	34	62	68
Commodity cost recovery	89	120	2	12	87	108
WPL’s Western Wisconsin gas distribution expansion investments	43	44	—	—	43	44
IPL’s Duane Arnold Energy Center PPA amendment	30	42	30	42	—	—
Other	191	205	68	68	123	137
	$2,345	$2,261	$1,548	$1,577	$797	$684

Regulatory Liabilities

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

	Alliant Energy		IPL		WPL
	June 30, 2024	December 31, 2023	June 30, 2024	December 31, 2023	June 30, 2024	December 31, 2023
Tax-related	$601	$566	$296	$299	$305	$267
Cost of removal obligations	374	366	232	242	142	124
Derivatives	50	65	30	34	20	31
Commodity cost recovery	51	48	16	13	35	35
Other	60	85	44	56	16	29
	$1,136	$1,130	$618	$644	$518	$486

IPL [Member]

Regulatory Assets [Line Items]

Regulatory Assets

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

	Alliant Energy		IPL		WPL
	June 30, 2024	December 31, 2023	June 30, 2024	December 31, 2023	June 30, 2024	December 31, 2023
Tax-related	$958	$934	$848	$831	$110	$103
AROs	408	194	218	160	190	34
Pension and OPEB costs	334	347	165	171	169	176
Assets retired early	197	273	184	259	13	14
Derivatives	95	102	33	34	62	68
Commodity cost recovery	89	120	2	12	87	108
WPL’s Western Wisconsin gas distribution expansion investments	43	44	—	—	43	44
IPL’s Duane Arnold Energy Center PPA amendment	30	42	30	42	—	—
Other	191	205	68	68	123	137
	$2,345	$2,261	$1,548	$1,577	$797	$684

Regulatory Liabilities

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

	Alliant Energy		IPL		WPL
	June 30, 2024	December 31, 2023	June 30, 2024	December 31, 2023	June 30, 2024	December 31, 2023
Tax-related	$601	$566	$296	$299	$305	$267
Cost of removal obligations	374	366	232	242	142	124
Derivatives	50	65	30	34	20	31
Commodity cost recovery	51	48	16	13	35	35
Other	60	85	44	56	16	29
	$1,136	$1,130	$618	$644	$518	$486

WPL [Member]

Regulatory Assets [Line Items]

Regulatory Assets

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

	Alliant Energy		IPL		WPL
	June 30, 2024	December 31, 2023	June 30, 2024	December 31, 2023	June 30, 2024	December 31, 2023
Tax-related	$958	$934	$848	$831	$110	$103
AROs	408	194	218	160	190	34
Pension and OPEB costs	334	347	165	171	169	176
Assets retired early	197	273	184	259	13	14
Derivatives	95	102	33	34	62	68
Commodity cost recovery	89	120	2	12	87	108
WPL’s Western Wisconsin gas distribution expansion investments	43	44	—	—	43	44
IPL’s Duane Arnold Energy Center PPA amendment	30	42	30	42	—	—
Other	191	205	68	68	123	137
	$2,345	$2,261	$1,548	$1,577	$797	$684

Regulatory Liabilities

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

	Alliant Energy		IPL		WPL
	June 30, 2024	December 31, 2023	June 30, 2024	December 31, 2023	June 30, 2024	December 31, 2023
Tax-related	$601	$566	$296	$299	$305	$267
Cost of removal obligations	374	366	232	242	142	124
Derivatives	50	65	30	34	20	31
Commodity cost recovery	51	48	16	13	35	35
Other	60	85	44	56	16	29
	$1,136	$1,130	$618	$644	$518	$486