Regulatory Matters

9 Months Ended

Sep. 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
	September 30, 2021	December 31, 2020	September 30, 2021	December 31, 2020	September 30, 2021	December 31, 2020
Tax-related	$931	$890	$881	$843	$50	$47
Pension and OPEB costs	549	580	276	291	273	289
Asset retirement obligations	124	119	85	81	39	38
Assets retired early	98	113	69	77	29	36
IPL’s DAEC PPA amendment	96	110	96	110	—	—
WPL’s Western Wisconsin gas distribution expansion investments	53	55	—	—	53	55
Commodity cost recovery	32	4	17	1	15	3
Derivatives	4	26	4	13	—	13
Other	131	113	79	67	52	46
	$2,018	$2,010	$1,507	$1,483	$511	$527

Commodity cost recovery - 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 September 30, 2021, IPL’s cumulative under-collection of natural gas costs was $15 million. 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.

The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. In 2021, WPL’s actual fuel-related costs fell outside these fuel monitoring ranges, resulting in a $12 million deferral as of September 30, 2021.

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

	Alliant Energy		IPL		WPL
	September 30, 2021	December 31, 2020	September 30, 2021	December 31, 2020	September 30, 2021	December 31, 2020
Tax-related	$611	$732	$313	$331	$298	$401
Cost of removal obligations	383	367	252	238	131	129
Derivatives	221	28	104	25	117	3
Electric transmission cost recovery	53	68	29	39	24	29
WPL’s West Riverside liquidated damages	40	38	—	—	40	38
Other	53	73	22	43	31	30
	$1,361	$1,306	$720	$676	$641	$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 nine months ended September 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
	September 30, 2021	December 31, 2020	September 30, 2021	December 31, 2020	September 30, 2021	December 31, 2020
Tax-related	$931	$890	$881	$843	$50	$47
Pension and OPEB costs	549	580	276	291	273	289
Asset retirement obligations	124	119	85	81	39	38
Assets retired early	98	113	69	77	29	36
IPL’s DAEC PPA amendment	96	110	96	110	—	—
WPL’s Western Wisconsin gas distribution expansion investments	53	55	—	—	53	55
Commodity cost recovery	32	4	17	1	15	3
Derivatives	4	26	4	13	—	13
Other	131	113	79	67	52	46
	$2,018	$2,010	$1,507	$1,483	$511	$527

Commodity cost recovery - 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 September 30, 2021, IPL’s cumulative under-collection of natural gas costs was $15 million. 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.

The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. In 2021, WPL’s actual fuel-related costs fell outside these fuel monitoring ranges, resulting in a $12 million deferral as of September 30, 2021.

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

	Alliant Energy		IPL		WPL
	September 30, 2021	December 31, 2020	September 30, 2021	December 31, 2020	September 30, 2021	December 31, 2020
Tax-related	$611	$732	$313	$331	$298	$401
Cost of removal obligations	383	367	252	238	131	129
Derivatives	221	28	104	25	117	3
Electric transmission cost recovery	53	68	29	39	24	29
WPL’s West Riverside liquidated damages	40	38	—	—	40	38
Other	53	73	22	43	31	30
	$1,361	$1,306	$720	$676	$641	$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 nine months ended September 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
	September 30, 2021	December 31, 2020	September 30, 2021	December 31, 2020	September 30, 2021	December 31, 2020
Tax-related	$931	$890	$881	$843	$50	$47
Pension and OPEB costs	549	580	276	291	273	289
Asset retirement obligations	124	119	85	81	39	38
Assets retired early	98	113	69	77	29	36
IPL’s DAEC PPA amendment	96	110	96	110	—	—
WPL’s Western Wisconsin gas distribution expansion investments	53	55	—	—	53	55
Commodity cost recovery	32	4	17	1	15	3
Derivatives	4	26	4	13	—	13
Other	131	113	79	67	52	46
	$2,018	$2,010	$1,507	$1,483	$511	$527

Commodity cost recovery - 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 September 30, 2021, IPL’s cumulative under-collection of natural gas costs was $15 million. 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.

The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. In 2021, WPL’s actual fuel-related costs fell outside these fuel monitoring ranges, resulting in a $12 million deferral as of September 30, 2021.

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

	Alliant Energy		IPL		WPL
	September 30, 2021	December 31, 2020	September 30, 2021	December 31, 2020	September 30, 2021	December 31, 2020
Tax-related	$611	$732	$313	$331	$298	$401
Cost of removal obligations	383	367	252	238	131	129
Derivatives	221	28	104	25	117	3
Electric transmission cost recovery	53	68	29	39	24	29
WPL’s West Riverside liquidated damages	40	38	—	—	40	38
Other	53	73	22	43	31	30
	$1,361	$1,306	$720	$676	$641	$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 nine months ended September 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.