Pension and Other Postretirement Benefits

The components of net periodic benefit cost were as follows:



	First quarter ended
	March 31,
	2018			2017
Pension benefits
Service cost	$	20		$	23
Interest cost	55			58
Expected return on plan assets	(77		)	(83		)
Recognized net actuarial loss	42			55
Amortization of prior service cost (benefit)	1			1
Curtailments	5			—
Net periodic benefit cost⁽¹⁾	$	46		$	54

Other postretirement benefits
Service cost	$	2		$	2
Interest cost	7			8
Recognized net actuarial loss	2			1
Amortization of prior service cost (benefit)	(2		)	(2		)
Net periodic benefit cost⁽¹⁾	$	9		$	9


⁽¹⁾	Service cost was included within Cost of goods sold, Selling, general administrative, and other expenses, and Research and development expenses; curtailments were included in Restructuring and other charges; and all other cost components were recorded in Other expense (income), net in the Statement of Consolidated Operations.

On April 1, 2018, benefit accruals for future service and compensation under all of the Company's qualified and non-qualified defined benefit pension plans for U.S. salaried and non-bargaining hourly employees ceased. As a result of this change, in the first quarter of 2018, the Company recorded a decrease to the accrued pension benefit liability of $136 related to the reduction of future benefits ($141 offset in Accumulated other comprehensive loss) and curtailment charges of $5 in Restructuring and other charges.

In conjunction with the separation of Alcoa Inc. on November 1, 2016, the Pension Benefit Guaranty Corporation approved management’s plan to separate the Alcoa Inc. pension plans between Arconic Inc. and Alcoa Corporation. The plan stipulates that Arconic will make cash contributions over a period of 30 months (from November 1, 2016) to its two largest pension plans. Payments are expected to be made in three increments of no less than $50 each ($150 total) over this 30-month period. The Company made payments of $50 in March 2018 and $50 in April 2017. Upon finalization of 2018 pension plan valuations, additional cash contributions that were made in the first quarter of 2018 may be used to satisfy the $150 requirement.