EMPLOYEE BENEFIT PLANS (Tables)

3 Months Ended

Mar. 31, 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
	March 31,
	2020			2019
	(Thousands of dollars)
Components of net periodic benefit cost
Service cost	$	3,217		$	3,008
Interest cost	8,545			10,168
Expected return on assets	(15,280		)	(15,485		)
Amortization of net loss	10,580			8,260
Net periodic benefit cost	$	7,062		$	5,951

	Other Postemployment Benefits
	Three Months Ended
	March 31,
	2020			2019
	(Thousands of dollars)
Components of net periodic benefit cost (credit)
Service cost	$	423		$	434
Interest cost	1,889			2,329
Expected return on assets	(3,867		)	(3,147		)
Amortization of unrecognized prior service credit	(29		)	(168		)
Amortization of net loss	43			561
Net periodic benefit cost (credit)	$	(1,541	)	$	9