Regulatory Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2023

Regulatory Assets and Liabilities Disclosure [Abstract]

Components of regulatory assets:


(Millions of Dollars)	See Note(s)	Remaining Amortization Period	Dec. 31, 2023				Dec. 31, 2022 (a)
Regulatory Assets			Current		Noncurrent		Current		Noncurrent
Pension and retiree medical obligations	9	Various	$	2	$	147	$	2	$	146
Net AROs (b)	1, 10	Various	—		59		—		48
Excess deferred taxes — TCJA	7	Various	1		47		1		48
Recoverable deferred taxes on AFUDC		Plant lives	—		44		—		40
Losses on reacquired debt		Term of related debt	1		18		1		19
Deferred electric energy/fuel costs		N/A	—		—		136		34


Other		Various	26		34		77		24
Total regulatory assets			$	30	$	349	$	217	$	359

(a)Prior period amounts have been restated to conform with current year presentation.

(b)Includes amounts recorded for future recovery of AROs.

Regulatory Liabilities

Components of regulatory liabilities:


(Millions of Dollars)	See Note(s)	Remaining Amortization Period	Dec. 31, 2023				Dec. 31, 2022 (a)
Regulatory Liabilities			Current		Noncurrent		Current		Noncurrent
Deferred income tax adjustments and TCJA refunds (b)	7	Various	$	—	$	458	$	—	$	469
Plant removal costs	1, 10	Various	—		223		—		198
LP&L departure payment		Up to 10 years	33		33		—		—
Effects of regulation on employee benefit costs		Various	—		19		—		20
Formula rates		One to two years	13		10		10		8
Renewable resources and environmental initiatives		Various	—		8		—		14
Contract valuation adjustments (c)	1, 8	Less than one year	41		—		119		1
Deferred electric energy costs		Less than one year	15		—		—		—
Other		Various	14		10		19		5
Total regulatory liabilities			$	116	$	761	$	148	$	715

(a)Prior period amounts have been reclassified to conform with current year presentation.

(b)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.

(c)Includes the fair value of FTR instruments utilized/intended to offset the impacts of transmission system congestion.