Employee Benefits (Tables)

6 Months Ended

Jun. 30, 2017

Retirement Benefits [Abstract]

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

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

	Pension Plans
	Three Months Ended June 30,					Six Months Ended June 30,
	2017			2016		2017		2016
	(Dollars in millions)
Service cost	$	14		15		31		32
Interest cost	105			107		206		214
Expected return on plan assets	(167		)	(183	)	(333	)	(367	)
Recognition of prior service credit	(2		)	(2	)	(4	)	(4	)
Recognition of actuarial loss	52			45		103		87
Net periodic pension benefit expense (income)	$	2		(18	)	3		(38	)

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

	Post-Retirement Benefit Plans
	Three Months Ended June 30,					Six Months Ended June 30,
	2017			2016		2017		2016
	(Dollars in millions)
Service cost	$	5		5		9		10
Interest cost	25			27		50		55
Expected return on plan assets	(1		)	(2	)	(1	)	(4	)
Recognition of prior service cost	5			5		10		10
Net periodic post-retirement benefit expense	$	34		35		68		71