EMPLOYEE BENEFIT PLANS (Tables)

3 Months Ended

Mar. 31, 2024

Employee Benefit Plans [Line Items]

Schedule of Net Benefit Costs [Table Text Block]

The following tables set forth the components of net periodic benefit cost for our pension and other postemployment benefit plans for the periods indicated:

		Pension Benefits
		Three Months Ended March 31,
		2024		2023
	(Thousands of dollars)
Components of net periodic benefit cost (credit)
Service cost		$	1,551	$	1,811
Interest cost (a)		10,281		10,607
Expected return on assets (a)		(14,757)		(14,879)
Amortization of unrecognized prior service cost (a)		93		93
Amortization of net loss (a)		1,446		502
Net periodic benefit cost (credit)		$	(1,386)	$	(1,866)
(a) These amounts, net of any amounts capitalized as a regulatory asset, have been recognized as other income (expense), net in the consolidated statement of income. See Note 11 for additional detail for our other income (expense), net.

	Other Postemployment Benefits
	Three Months Ended March 31,
	2024		2023
	(Thousands of dollars)
Components of net periodic benefit cost (credit)
Service cost	$	152	$	183
Interest cost (a)	2,045		2,288
Expected return on assets (a)	(2,284)		(2,432)
Amortization of unrecognized prior service cost (credit) (a)	—		38
Amortization of net (gain) loss (a)	(4)		(12)
Net periodic benefit cost (credit)	$	(91)	$	65
(a) These amounts, net of any amounts capitalized as a regulatory asset, have been recognized as other income (expense), net in the consolidated statement of income. See Note 11 for additional detail for our other income (expense), net.