Pension Plan and Other Postretirement Benefits

The Company provides a qualified, defined-benefit, non-contributory pension plan for substantially all employees. The Company makes annual contributions to fund the amounts accrued for in the qualified pension plan. The Company also maintains an unfunded, non-qualified, supplemental executive retirement plan. The costs of the plans are charged to expense or are capitalized in utility plant as appropriate.

The Company offers medical, dental, vision, and life insurance benefits for retirees and their spouses and dependents. Participants are required to pay a premium, which offsets a portion of the cost.

Cash contributions by the Company related to pension plans were $16.0 million and $14.8 million for the six months ended June 30, 2018 and 2017, respectively. Cash contributions by the Company related to other postretirement benefit plans were $2.7 million for the six months ended June 30, 2018 and no cash contributions were made for the six months ended June 30, 2017. The total 2018 estimated cash contribution to the pension plans is $33.4 million and to the other postretirement benefit plans is $10.1 million.

The following table lists components of net periodic benefit costs for the pension plans and other postretirement benefits. The data listed under “pension plan” includes the qualified pension plan and the non-qualified supplemental executive retirement plan. The data listed under “other benefits” is for all other postretirement benefits.



	Three Months Ended June 30
	Pension Plan						Other Benefits
	2018			2017			2018			2017
Service cost	$	7,402		$	5,865		$	2,550		$	2,019
Interest cost	5,995			5,791			1,484			1,491
Expected return on plan assets	(6,862		)	(6,029		)	(1,416		)	(1,218		)
Amortization of prior service cost	1,263			1,445			11			11
Recognized net actuarial loss	2,797			1,752			773			649
Net periodic benefit cost	$	10,595		$	8,824		$	3,402		$	2,952



	Six Months Ended June 30
	Pension Plan						Other Benefits
	2018			2017			2018			2017
Service cost	$	14,804		$	11,730		$	5,100		$	4,038
Interest cost	11,989			11,581			2,969			2,982
Expected return on plan assets	(13,725		)	(12,058		)	(2,832		)	(2,436		)
Amortization of prior service cost	2,526			2,890			21			22
Recognized net actuarial loss	5,595			3,504			1,547			1,298
Net periodic benefit cost	$	21,189		$	17,647		$	6,805		$	5,904

Service cost portion of the pension plan and other postretirement benefits is recognized in administrative and general within the Condensed Consolidated Statements of Income. Other components of net periodic benefit costs include interest costs, expected return on plan assets, amortization of prior service costs, and recognized net actuarial loss and are reported together as other components of net periodic benefit costs within the Condensed Consolidated Statements of Income (see note 2).