Regulatory Matters (Tables)

6 Months Ended

Jun. 30, 2023

Regulatory Assets [Line Items]

Regulatory Assets

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

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$957	$929	$868	$848	$89	$81
Pension and OPEB costs	378	392	190	197	188	195
Assets retired early	290	70	274	53	16	17
Asset retirement obligations	197	151	156	110	41	41
Commodity cost recovery	145	160	6	1	139	159
Derivatives	102	84	41	48	61	36
IPL’s Duane Arnold Energy Center PPA amendment	54	66	54	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	47	48	—	—	47	48
Other	174	146	59	63	115	83
	$2,344	$2,046	$1,648	$1,386	$696	$660

Regulatory Liabilities

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

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$572	$579	$301	$303	$271	$276
Cost of removal obligations	405	398	260	259	145	139
Derivatives	90	210	48	115	42	95
Commodity cost recovery	39	40	15	38	24	2
Electric transmission cost recovery	19	20	14	10	5	10
WPL’s West Riverside liquidated damages	17	32	—	—	17	32
Other	66	45	38	29	28	16
	$1,208	$1,324	$676	$754	$532	$570

IPL [Member]

Regulatory Assets [Line Items]

Regulatory Assets

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

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$957	$929	$868	$848	$89	$81
Pension and OPEB costs	378	392	190	197	188	195
Assets retired early	290	70	274	53	16	17
Asset retirement obligations	197	151	156	110	41	41
Commodity cost recovery	145	160	6	1	139	159
Derivatives	102	84	41	48	61	36
IPL’s Duane Arnold Energy Center PPA amendment	54	66	54	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	47	48	—	—	47	48
Other	174	146	59	63	115	83
	$2,344	$2,046	$1,648	$1,386	$696	$660

Regulatory Liabilities

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

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$572	$579	$301	$303	$271	$276
Cost of removal obligations	405	398	260	259	145	139
Derivatives	90	210	48	115	42	95
Commodity cost recovery	39	40	15	38	24	2
Electric transmission cost recovery	19	20	14	10	5	10
WPL’s West Riverside liquidated damages	17	32	—	—	17	32
Other	66	45	38	29	28	16
	$1,208	$1,324	$676	$754	$532	$570

WPL [Member]

Regulatory Assets [Line Items]

Regulatory Assets

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

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$957	$929	$868	$848	$89	$81
Pension and OPEB costs	378	392	190	197	188	195
Assets retired early	290	70	274	53	16	17
Asset retirement obligations	197	151	156	110	41	41
Commodity cost recovery	145	160	6	1	139	159
Derivatives	102	84	41	48	61	36
IPL’s Duane Arnold Energy Center PPA amendment	54	66	54	66	—	—
WPL’s Western Wisconsin gas distribution expansion investments	47	48	—	—	47	48
Other	174	146	59	63	115	83
	$2,344	$2,046	$1,648	$1,386	$696	$660

Regulatory Liabilities

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

	Alliant Energy		IPL		WPL
	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022	June 30, 2023	December 31, 2022
Tax-related	$572	$579	$301	$303	$271	$276
Cost of removal obligations	405	398	260	259	145	139
Derivatives	90	210	48	115	42	95
Commodity cost recovery	39	40	15	38	24	2
Electric transmission cost recovery	19	20	14	10	5	10
WPL’s West Riverside liquidated damages	17	32	—	—	17	32
Other	66	45	38	29	28	16
	$1,208	$1,324	$676	$754	$532	$570