Employee Benefits

Net periodic benefit expense (income) for our qualified and non-qualified pension plans included the following components:



	Pension Plans
	Three Months Ended September 30,					Nine Months Ended September 30,
	2017			2016		2017		2016
	(Dollars in millions)
Service cost	$	16		16		47		48
Interest cost	102			107		308		321
Expected return on plan assets	(166		)	(183	)	(499	)	(550	)
Recognition of prior service credit	(2		)	(2	)	(6	)	(6	)
Recognition of actuarial loss	51			44		154		131
Net periodic pension benefit expense (income)	$	1		(18	)	4		(56	)

Net periodic benefit expense for our post-retirement benefit plans included the following components:



	Post-Retirement Benefit Plans
	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
	(Dollars in millions)
Service cost	$	4	4		13		14
Interest cost	25		29		75		84
Expected return on plan assets	—		(2	)	(1	)	(6	)
Recognition of prior service cost	5		5		15		15
Net periodic post-retirement benefit expense	$	34	36		102		107

We report service cost for our qualified pension and post-retirement benefit plans in cost of services and products and selling, general and administrative expenses in our consolidated statements of operations. Additionally, a portion of the service cost is also allocated to certain assets under construction, which are capitalized and reflected as part of property, plant and equipment in our consolidated balance sheets. The remaining components of net periodic benefit expense (income) are reported in other income (expense), net in our consolidated statements of operations. The expected rate of return on plan assets is the long-term rate of return we expect to earn on the plans' assets, net of administrative expenses paid from plan assets.

Benefits paid by our qualified pension plan are paid through a trust that holds all plan assets. Based on current laws and circumstances, we do not expect any contributions to be required for our qualified pension plan during the remainder of 2017. However, we made a voluntary contribution of $100 million to the trust for our qualified pension plan in the third quarter of 2017.