Employee Benefits (Tables)

6 Months Ended

Jun. 30, 2020

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,
	2020		2019	2020	2019
	(Dollars in millions)
Service cost	$	13	14	29	28
Interest cost	80		107	162	217
Expected return on plan assets	(149)		(153)	(298)	(309)
Recognition of prior service credit	(1)		(2)	(4)	(4)
Recognition of actuarial loss	52		56	102	113
Net periodic pension benefit (income) expense	$	(5)	22	(9)	45

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,
	2020		2019	2020	2019
	(Dollars in millions)
Service cost	$	3	4	7	8
Interest cost	20		28	40	55
Recognition of prior service cost	4		4	8	8
Net periodic post-retirement benefit expense	$	27	36	55	71