Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2021

Retirement Benefits [Abstract]

Schedule of Changes in Benefit Obligation and Plan Assets

Table 14.1: Changes in Benefit Obligation and Plan Assets

	Defined Pension  Benefits				Other Postretirement Benefits
(Dollars in millions)	2021		2020		2021		2020
Change in benefit obligation:
Accumulated benefit obligation as of January 1,	$	178	$	165	$	21	$	27
Service cost	1		1		0		0
Interest cost	4		5		0		1
Benefits paid	(12)		(11)		(2)		(2)
Actuarial loss (gain)	(8)		18		(3)		(5)
Accumulated benefit obligation as of December 31,	$	163	$	178	$	16	$	21
Change in plan assets:
Fair value of plan assets as of January 1,	$	274	$	254	$	6	$	6
Actual return on plan assets	10		30		1		1
Employer contributions	1		1		1		1
Benefits paid	(12)		(11)		(2)		(2)
Fair value of plan assets as of December 31,	$	273	$	274	$	6	$	6
Over (under) funded status as of December 31,	$	110	$	96	$	(10)	$	(15)

	Defined Pension  Benefits				Other Postretirement Benefits
(Dollars in millions)	2021		2020		2021		2020
Balance sheet presentation as of December 31,
Other assets	$	121	$	108	$	0	$	0
Other liabilities	(11)		(12)		(10)		(15)
Net amount recognized as of December 31,	$	110	$	96	$	(10)	$	(15)