Employee Benefits (Tables)

6 Months Ended

Jun. 30, 2019

Retirement Benefits [Abstract]

Schedule of components of net periodic pension benefit (income) expense and post-retirement benefit expense

Net periodic benefit (income) expense for our combined pension plan includes the following components:

	Combined Pension Plan
	Three Months Ended June 30,					Six Months Ended June 30,
	2019			2018		2019		2018
	(Dollars in millions)
Service cost	$	14		17		28		33
Interest cost	107			96		217		196
Expected return on plan assets	(153		)	(169	)	(309	)	(342	)
Recognition of prior service credit	(2		)	(2	)	(4	)	(4	)
Recognition of actuarial loss	56			45		113		89
Net periodic pension benefit expense (income)	$	22		(13	)	45		(28	)

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

	Post-Retirement Benefit Plans
	Three Months Ended June 30,			Six Months Ended June 30,
	2019		2018	2019	2018
	(Dollars in millions)
Service cost	$	4	5	8	9
Interest cost	28		25	55	49
Recognition of prior service cost	4		5	8	10
Net periodic post-retirement benefit expense	$	36	35	71	68