EMPLOYEE BENEFIT PLANS (Notes)

6 Months Ended

Jun. 30, 2019

Employee Benefit Plans [Line Items]

EMPLOYEE BENEFIT PLANS

EMPLOYEE BENEFIT PLANS

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						Six Months Ended
	June 30,						June 30,
	2019			2018			2019			2018
	(Thousands of dollars)
Components of net periodic benefit cost
Service cost	$	3,008		$	3,230		$	6,016		$	6,460
Interest cost (a)	10,168			9,200			20,336			18,400
Expected return on assets (a)	(15,485		)	(15,145		)	(30,970		)	(30,290		)
Amortization of net loss (a)	8,260			9,978			16,520			19,956
Net periodic benefit cost	$	5,951		$	7,263		$	11,902		$	14,526

(a) These amounts, net of any amounts capitalized as a regulatory asset since adoption of ASU 2017-07 on January 1, 2018, have been recognized as other income (expense), net in the consolidated statements of income. See Note 12 for additional detail of our other income (expense), net.

	Other Postemployment Benefits
	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2019			2018			2019			2018
	(Thousands of dollars)
Components of net periodic benefit cost (credit)
Service cost	$	434		$	589		$	868		$	1,178
Interest cost (a)	2,329			2,279			4,658			4,558
Expected return on assets (a)	(3,147		)	(3,571		)	(6,294		)	(7,142		)
Amortization of unrecognized prior service credit (a)	(168		)	(1,142		)	(336		)	(2,284		)
Amortization of net loss (a)	561			972			1,122			1,944
Net periodic benefit cost (credit)	$	9		$	(873	)	$	18		$	(1,746	)

(a) These amounts, net of any amounts capitalized as a regulatory asset since adoption of ASU 2017-07 on January 1, 2018, have been recognized as other income (expense), net in the consolidated statements of income. See Note 12 for additional detail of our other income (expense), net.

We recover qualified pension benefit plan and other postemployment benefit plan costs through rates charged to our customers. Certain regulatory authorities require that the recovery of these costs be based on specific guidelines. The difference between these regulatory-based amounts and the periodic benefit cost calculated pursuant to GAAP is deferred as a regulatory asset or liability and amortized to expense over periods in which this difference will be recovered in rates, as authorized by the applicable regulatory authorities. Regulatory deferrals related to net periodic benefit cost were not material for the three and six months ended June 30, 2019 and 2018.

Since adoption of ASU 2017-07 on January 1, 2018, we continue to capitalize all eligible service cost and non-service cost components under the accounting requirements of ASC Topic 980 (Regulated Operations) for rate-regulated entities. Our consolidated balance sheets reflect the capitalized non-service cost components as a regulatory asset. We have recognized a regulatory asset of $2.9 million and $1.5 million as of June 30, 2019 and December 31, 2018, respectively. See Note 3 of the Notes to Consolidated Financial Statements in this Quarterly Report for additional information.