Pension and Postretirement Plans (Tables)

3 Months Ended

Mar. 31, 2022

Compensation And Retirement Disclosure [Abstract]

Schedule of Pension and Postretirement Costs (Benefits)

Pension and postretirement (benefits) costs are as follows:

	Pension Benefits						Postretirement and Other Benefits
	Successor			Predecessor			Successor		Predecessor
(dollars in millions)	Three Months Ended March 31, 2022			Three Months Ended March 31, 2021			Three Months Ended March 31, 2022		Three Months Ended March 31, 2021
Service cost	$	—		$	—		$	0.1	$	0.1
Other components of pension and postretirement benefit plans expense:
Interest cost on projected benefit obligation		3.9			3.8			0.7		0.6
Expected return on plan assets		(7.2	)		(7.5	)		—		—
Amortization of:
Prior service benefit		—			—			—		(0.6	)
Actuarial loss		—			6.3			—		—
Pension / postretirement (benefit) cost	$	(3.3	)	$	2.6		$	0.8	$	0.1