ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)

9 Months Ended

Sep. 30, 2024

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

Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]

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

	Three Months Ended				Nine Months Ended				Affected Line Item in the
Details About Accumulated Other	September 30,				September 30,				Consolidated Statements
Comprehensive Loss Components	2024		2023		2024		2023		of Income
	(Thousands of dollars)
Pension and other postemployment benefit plan obligations (a)
Amortization of net loss	$	1,442	$	490	$	4,326	$	1,470
Amortization of unrecognized prior service cost	93		131		279		393
	1,535		621		4,605		1,863
Regulatory adjustments (b)	(1,536)		(620)		(4,607)		(1,862)
Total pension and other postemployment benefit obligations	(1)		1		(2)		1
Available-for-sale securities
Unrealized holding gains (losses) on available-for-sale securities	324		—		322		—
Realized gains (losses)	(1)		—		(11)		—
Amounts reclassified from accumulated other comprehensive income	1		—		11		—
Total available-for-sale securities	324		—		322		—
	323		1		320		1		Income before income taxes
	(68)		—		(67)		—		Income tax expense
Total reclassifications for the period	$	255	$	1	$	253	$	1	Net income

(a) These components of accumulated other comprehensive loss are included in the computation of net periodic benefit cost. See Note 9 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.