Employee Retirement Benefits (Tables)

3 Months Ended

Mar. 31, 2024

Retirement Benefits [Abstract]

Schedule of Defined Benefit Plans Disclosures

The following summarizes the components of net periodic benefit for our qualified and supplemental pension plans:

(Dollars in millions)	Three months ended March 31,
	2024		2023
Service cost	$	1	$	1
Non-service (benefit) costs:
Interest cost	3		3
Expected return on plan assets	(5)		(5)
Amortization of actuarial loss and prior service cost	—		(1)
Other	—		(5)
Total non-service benefit	(2)		(8)
Net periodic benefit	$	(1)	$	(7)