Retirement Plans (Tables)

3 Months Ended

Mar. 31, 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 March 31 were as follows:

	Pension Benefits
(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
Other	2		—
Net periodic benefit cost	$	4	$	3