v3.25.2
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)
 6 Months Ended
Jun. 30, 2025
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 income (loss) in our consolidated statements of income for the periods indicated:

Three Months EndedSix Months EndedAffected Line Item in the
Details About Accumulated Other June 30,June 30,Consolidated Statements
Comprehensive Income (Loss) Components2025202420252024of Income
(Thousands of dollars)
Pension and other postemployment benefit plan obligations (a)
Amortization of net gain (loss)$(1,834)$(1,442)$(3,668)$(2,884)
Amortization of unrecognized prior service credit (cost)(93)(93)(186)(186)
(1,927)(1,535)(3,854)(3,070)
Regulatory adjustments (b)1,928 1,536 3,855 3,071 
Amounts reclassified from accumulated other comprehensive income (loss)1 1 1 1 Other income (expense), net
Available-for-sale securities
Amounts reclassified from accumulated other comprehensive income (loss)4 (11)7 (10)Other income (expense), net
Total available-for-sale securities4 (11)7 (10)
Total reclassifications before tax5 (10)8 (9)Income before income taxes
Tax effect of reclassifications(1)2 (2)2 Income tax expense
Net reclassifications for the period$4 $(8)$6 $(7)Net income
(a) These components of accumulated other comprehensive income (loss) are included in the computation of net periodic benefit cost (credit). See Note 9 for additional detail of our net periodic benefit cost (credit).
(b) Regulatory adjustments represent pension and other postemployment benefit credits or 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.