Pension Plans And Other Postretirement Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2018

Components of Net Periodic Benefit Cost

	Pension Benefits						Other Postretirement Benefits
	2018			2017			2018			2017
Three months ended March 31:
Service cost (a)	$	5,450		$	5,042		$	804		$	824
Interest cost	6,466			6,951			1,197			1,399
Expected return on plan assets	(8,250		)	(7,900		)	(500		)	(475		)
Amortization of prior service cost	75			—			(815		)	(312		)
Net loss recognition	2,088			2,546			1,655			1,273
Net periodic benefit cost	$	5,829		$	6,639		$	2,341		$	2,709

(a) Total service costs in the table above are recorded to the same accounts as labor expense. Labor and benefits expense is recorded to various projects based on whether the work is a capital project or an operating expense. Approximately 40 percent of all labor and benefits is capitalized to utility property and 60 percent is expensed to utility other operating expenses.