10. Employee Retirement Plans

The following table summarizes the components of net periodic benefit cost for Corning’s defined benefit pension and postretirement health care and life insurance plans (in millions):



	Pension benefits								Postretirement benefits
	Three months ended				Nine months ended				Three months ended				Nine months ended
	September 30,				September 30,				September 30,				September 30,
	2018		2017		2018		2017		2018		2017		2018		2017

Service cost	$	26	$	22	$	77	$	69	$	3	$	2	$	9	$	7
Interest cost		32		32		97		94		6		7		18		20
Expected return on plan assets		(47)		(43)		(142)		(130)
Amortization of prior service cost (credit)		2		1		6		4		(2)		(1)		(5)		(2)
Recognition of actuarial loss						1		15
Total pension and postretirement benefit expense	$	13	$	12	$	39	$	52	$	7	$	8	$	22	$	25

The components of net period benefit cost other than the service cost component are included in the line item “Other expense, net” in the consolidated statements of income.

On January 1, 2018, we adopted Compensation—Retirement Benefits: Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The service cost component of net periodic pension and postretirement benefit cost is presented with other current compensation costs in operating income. The remaining components are included in the line item Other income (expense), net, in the consolidated statements of income.

Corning has applied the practical expedient which permits it to use the amounts disclosed in its pension and other postretirement benefit plan note for the prior comparative periods as the estimation basis for applying the retrospective presentation requirements. See Note 1 (Significant Accounting Policies) for additional information.