ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Notes)

12 Months Ended

Dec. 31, 2023

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

Comprehensive Income (Loss) Note

ACCUMULATED OTHER COMPREHENSIVE LOSS

The following table sets forth the balance in accumulated other comprehensive loss for the periods indicated:

	Accumulated Other Comprehensive Income (Loss)
	(Thousands of dollars)
January 1, 2022	$	(6,527)
Pension and other postemployment benefit plans obligations
Other comprehensive income before reclassification, net of tax of $(1,669)	5,701
Amounts reclassified from accumulated other comprehensive income (loss), net of tax of $(36)	122
Other comprehensive income	5,823
December 31, 2022	(704)
Pension and other postemployment benefit plans obligations
Other comprehensive loss before reclassification, net of tax of $140	(479)
Amounts reclassified from accumulated other comprehensive income, net of tax of $—	1
Other comprehensive loss	(478)
December 31, 2023	$	(1,182)

The following table sets forth the effect of reclassifications from accumulated other comprehensive loss in our consolidated statements of income for the periods indicated:

	Years Ended						Affected Line Item in the
Details About Accumulated Other	December 31,						Consolidated Statements
Comprehensive Loss Components	2023		2022		2021		of Income
	(Thousands of dollars)
Pension and other postemployment benefit plan obligations (a)
Amortization of net loss	$	1,960	$	17,010	$	45,896
Amortization of unrecognized prior service cost	525		289		(279)
	2,485		17,299		45,617
Regulatory adjustments (b)	(2,484)		(17,141)		(44,055)
	1		158		1,562		Income before income taxes
	—		(36)		(390)		Income tax expense
Total reclassifications for the period	$	1	$	122	$	1,172	Net income

(a) These components of accumulated other comprehensive loss are included in the computation of net periodic benefit cost. See Note 11 for additional detail of our net periodic benefit cost.

(b) Regulatory adjustments represent pension and other postemployment benefit costs expected to be recovered through rates and are deferred as part of our regulatory assets. See Note 3 for additional disclosures of regulatory assets and liabilities.