EMPLOYEE BENEFIT PLANS (Tables)

9 Months Ended

Sep. 30, 2020

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				Nine Months Ended
	September 30,				September 30,
	2020		2019		2020		2019
	(Thousands of dollars)
Components of net periodic benefit cost
Service cost	$	3,217	$	3,008	$	9,651	$	9,024
Interest cost	8,545		10,168		25,635		30,504
Expected return on assets	(15,280)		(15,485)		(45,840)		(46,455)
Amortization of net loss	10,580		8,260		31,740		24,780
Net periodic benefit cost	$	7,062	$	5,951	$	21,186	$	17,853

	Other Postemployment Benefits
	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2020		2019		2020		2019
	(Thousands of dollars)
Components of net periodic benefit cost (credit)
Service cost	$	423	$	434	$	1,269	$	1,302
Interest cost	1,889		2,329		5,667		6,987
Expected return on assets	(3,867)		(3,147)		(11,601)		(9,441)
Amortization of unrecognized prior service credit	(29)		(168)		(87)		(504)
Amortization of net loss	43		561		129		1,683
Net periodic benefit cost (credit)	$	(1,541)	$	9	$	(4,623)	$	27