Regulatory Assets and Liabilities

12 Months Ended

Dec. 31, 2023

Regulatory Assets and Liabilities Disclosure [Abstract]

Regulatory Assets and Liabilities

Regulatory assets and liabilities are created for amounts that regulators may allow to be collected or may require to be paid back to customers in future electric and natural gas rates. NSP-Wisconsin would be required to recognize the write-off of regulatory assets and liabilities in net income or other comprehensive income if changes in the utility industry no longer allow for the application of regulatory accounting guidance under GAAP.

Components of regulatory assets:

(Millions of Dollars)	See Note(s)	Remaining Amortization Period	Dec. 31, 2023				Dec. 31, 2022
Regulatory Assets			Current		Noncurrent		Current		Noncurrent
Pension and retiree medical obligations	9	Various	2		62		2		61
Environmental remediation costs	1, 10	Various	$	13	$	48	$	13	$	63
Recoverable deferred taxes on AFUDC		Plant lives	—		26		—		20
State commission adjustments		Plant lives	1		22		1		22
Net AROs (a)	1, 10	Various	—		21		—		18
Deferred natural gas and electric energy/fuel costs	7	Less than one year	1		—		23		—
Other		Various	7		6		5		9
Total regulatory assets			$	24	$	185	$	44	$	193

(a)Includes amounts recorded for future recovery of AROs, less amounts recovered through NSP-Wisconsin’s share of nuclear decommissioning accruals and gains from decommissioning investments.

Components of regulatory liabilities:

(Millions of Dollars)	See Note(s)	Remaining Amortization Period	Dec. 31, 2023				Dec. 31, 2022
Regulatory Liabilities			Current		Noncurrent		Current		Noncurrent
Plant removal costs	1, 10	Various	$	—	$	251	$	—	$	223
Deferred income tax adjustments and TCJA refunds (a)	7	Various	—		140		—		144
DOE Settlement		One to two years	4		6		12		3
Deferred natural gas and electric energy/fuel costs		Less than one year	28		—		5		—
Other		Various	10		10		4		13
Total regulatory liabilities			$	42	$	407	$	21	$	383

(a)Includes the revaluation of recoverable/regulated plant accumulated deferred income taxes and revaluation impact of non-plant accumulated deferred income taxes due to the TCJA.

NSP-Wisconsin’s regulatory assets not earning a return include the unfunded portion of pension and retiree medical obligations and net AROs (i.e. deferrals for where cash has not been disbursed). At Dec. 31, 2023 and 2022,