Retirement Plans (Tables)

6 Months Ended

Jun. 30, 2021

Retirement Benefits, Description [Abstract]

Schedule of Components of Net Periodic Benefit Cost

The components of net periodic benefit cost for the three months ended June 30 were as follows:

(Dollars in millions)	2021		2020
Components of net periodic benefit cost
Interest cost	$	4	$	6
Expected return on plan assets	(4)		(6)
Amortization of unrecognized:
Actuarial (gain) loss	2		3
Net periodic benefit cost	$	2	$	3

The components of net periodic benefit cost for the six months ended June 30 were as follows:

(Dollars in millions)	2021		2020
Components of net periodic benefit cost
Interest cost	$	8	$	12
Expected return on plan assets	(8)		(12)
Amortization of unrecognized:
Actuarial (gain) loss	4		6
Other	2		—
Net periodic benefit cost	$	6	$	6