Regulatory Matters

6 Months Ended

Jun. 30, 2021

Public Utilities, General Disclosures [Line Items]

Regulatory Matters

REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

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

	Alliant Energy		IPL		WPL
	June 30, 2021	December 31, 2020	June 30, 2021	December 31, 2020	June 30, 2021	December 31, 2020
Tax-related	$914	$890	$865	$843	$49	$47
Pension and OPEB costs	559	580	281	291	278	289
Asset retirement obligations	123	119	85	81	38	38
Assets retired early	103	113	72	77	31	36
IPL’s DAEC PPA amendment	102	110	102	110	—	—
WPL’s Western Wisconsin gas distribution expansion investments	54	55	—	—	54	55
Derivatives	3	26	2	13	1	13
Other	137	117	81	68	56	49
	$1,995	$2,010	$1,488	$1,483	$507	$527

Other - In February 2021, portions of the central and southern U.S., including Alliant Energy’s service territories, experienced a prolonged period of very cold temperatures and a series of winter storms. These events created significant volatility and increases in commodity prices caused by higher demand for electricity and natural gas and disruptions in commodity supply, resulting in IPL under-recovering its natural gas costs. In March 2021, IPL received approval from the IUB to spread recovery of these higher natural gas costs from its retail customers through December 2021. As of June 30, 2021, IPL’s cumulative under-collection of these natural gas costs was $14 million, which is included in “Other” regulatory assets in the above table. The extreme temperatures in February 2021 did not impact WPL’s natural gas costs and IPL’s and WPL’s fuel-related costs to the extent of IPL’s natural gas costs.

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

	Alliant Energy		IPL		WPL
	June 30, 2021	December 31, 2020	June 30, 2021	December 31, 2020	June 30, 2021	December 31, 2020
Tax-related	$661	$732	$322	$331	$339	$401
Cost of removal obligations	373	367	245	238	128	129
Derivatives	81	28	40	25	41	3
Electric transmission cost recovery	48	68	23	39	25	29
WPL’s West Riverside liquidated damages	40	38	—	—	40	38
Other	51	73	17	43	34	30
	$1,254	$1,306	$647	$676	$607	$630

Tax-related - Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities are primarily related to excess deferred tax benefits resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform. During the six months ended June 30, 2021, Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities decreased primarily due to returning a portion of these excess deferred tax benefits back to customers.

IPL [Member]

Public Utilities, General Disclosures [Line Items]

Regulatory Matters

REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

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

	Alliant Energy		IPL		WPL
	June 30, 2021	December 31, 2020	June 30, 2021	December 31, 2020	June 30, 2021	December 31, 2020
Tax-related	$914	$890	$865	$843	$49	$47
Pension and OPEB costs	559	580	281	291	278	289
Asset retirement obligations	123	119	85	81	38	38
Assets retired early	103	113	72	77	31	36
IPL’s DAEC PPA amendment	102	110	102	110	—	—
WPL’s Western Wisconsin gas distribution expansion investments	54	55	—	—	54	55
Derivatives	3	26	2	13	1	13
Other	137	117	81	68	56	49
	$1,995	$2,010	$1,488	$1,483	$507	$527

Other - In February 2021, portions of the central and southern U.S., including Alliant Energy’s service territories, experienced a prolonged period of very cold temperatures and a series of winter storms. These events created significant volatility and increases in commodity prices caused by higher demand for electricity and natural gas and disruptions in commodity supply, resulting in IPL under-recovering its natural gas costs. In March 2021, IPL received approval from the IUB to spread recovery of these higher natural gas costs from its retail customers through December 2021. As of June 30, 2021, IPL’s cumulative under-collection of these natural gas costs was $14 million, which is included in “Other” regulatory assets in the above table. The extreme temperatures in February 2021 did not impact WPL’s natural gas costs and IPL’s and WPL’s fuel-related costs to the extent of IPL’s natural gas costs.

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

	Alliant Energy		IPL		WPL
	June 30, 2021	December 31, 2020	June 30, 2021	December 31, 2020	June 30, 2021	December 31, 2020
Tax-related	$661	$732	$322	$331	$339	$401
Cost of removal obligations	373	367	245	238	128	129
Derivatives	81	28	40	25	41	3
Electric transmission cost recovery	48	68	23	39	25	29
WPL’s West Riverside liquidated damages	40	38	—	—	40	38
Other	51	73	17	43	34	30
	$1,254	$1,306	$647	$676	$607	$630

Tax-related - Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities are primarily related to excess deferred tax benefits resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform. During the six months ended June 30, 2021, Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities decreased primarily due to returning a portion of these excess deferred tax benefits back to customers.

WPL [Member]

Public Utilities, General Disclosures [Line Items]

Regulatory Matters

REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

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

	Alliant Energy		IPL		WPL
	June 30, 2021	December 31, 2020	June 30, 2021	December 31, 2020	June 30, 2021	December 31, 2020
Tax-related	$914	$890	$865	$843	$49	$47
Pension and OPEB costs	559	580	281	291	278	289
Asset retirement obligations	123	119	85	81	38	38
Assets retired early	103	113	72	77	31	36
IPL’s DAEC PPA amendment	102	110	102	110	—	—
WPL’s Western Wisconsin gas distribution expansion investments	54	55	—	—	54	55
Derivatives	3	26	2	13	1	13
Other	137	117	81	68	56	49
	$1,995	$2,010	$1,488	$1,483	$507	$527

Other - In February 2021, portions of the central and southern U.S., including Alliant Energy’s service territories, experienced a prolonged period of very cold temperatures and a series of winter storms. These events created significant volatility and increases in commodity prices caused by higher demand for electricity and natural gas and disruptions in commodity supply, resulting in IPL under-recovering its natural gas costs. In March 2021, IPL received approval from the IUB to spread recovery of these higher natural gas costs from its retail customers through December 2021. As of June 30, 2021, IPL’s cumulative under-collection of these natural gas costs was $14 million, which is included in “Other” regulatory assets in the above table. The extreme temperatures in February 2021 did not impact WPL’s natural gas costs and IPL’s and WPL’s fuel-related costs to the extent of IPL’s natural gas costs.

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

	Alliant Energy		IPL		WPL
	June 30, 2021	December 31, 2020	June 30, 2021	December 31, 2020	June 30, 2021	December 31, 2020
Tax-related	$661	$732	$322	$331	$339	$401
Cost of removal obligations	373	367	245	238	128	129
Derivatives	81	28	40	25	41	3
Electric transmission cost recovery	48	68	23	39	25	29
WPL’s West Riverside liquidated damages	40	38	—	—	40	38
Other	51	73	17	43	34	30
	$1,254	$1,306	$647	$676	$607	$630

Tax-related - Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities are primarily related to excess deferred tax benefits resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform. During the six months ended June 30, 2021, Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities decreased primarily due to returning a portion of these excess deferred tax benefits back to customers.