Pension and Postretirement Plans (Tables)

9 Months Ended

Sep. 30, 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			Successor			Predecessor			Successor		Successor		Predecessor
(dollars in millions)	Three Months Ended September 30, 2022			September 8, 2021 to September 30, 2021			July 1, 2021 to September 7, 2021			Three Months Ended September 30, 2022		September 8, 2021 to September 30, 2021		July 1, 2021 to September 7, 2021
Service cost	$	—		$	—		$	—		$	0.4	$	—	$	0.1
Other components of pension and postretirement benefit plans expense:
Interest cost on projected benefit obligation		4.2			0.9			2.7			1.7		0.1		0.5
Expected return on plan assets		(6.6	)		(2.1	)		(5.2	)		—		—		—
Amortization of:
Prior service benefit		—			—			—			—		—		(0.4	)
Actuarial loss		—			—			4.5			—		—		—
Pension / postretirement (benefit) cost	$	(2.4	)	$	(1.2	)	$	2.0		$	2.1	$	0.1	$	0.2

	Pension Benefits									Postretirement and Other Benefits
	Successor			Successor			Predecessor			Successor		Successor		Predecessor
(dollars in millions)	Nine Months Ended September 30, 2022			September 8, 2021 to September 30, 2021			January 1, 2021 to September 7, 2021			Nine Months Ended September 30, 2022		September 8, 2021 to September 30, 2021		January 1, 2021 to September 7, 2021
Service cost	$	—		$	—		$	—		$	0.6	$	—	$	0.3
Other components of pension and postretirement benefit plans expense:
Interest cost on projected benefit obligation		11.9			0.9			10.2			3.1		0.1		1.8
Expected return on plan assets		(20.9	)		(2.1	)		(19.9	)		—		—		—
Amortization of:
Prior service benefit		—			—			—			—		—		(1.7	)
Actuarial loss		—			—			16.0			—		—		—
Pension / postretirement (benefit) cost	$	(9.0	)	$	(1.2	)	$	6.3		$	3.7	$	0.1	$	0.4