Pension and Savings Plans (Tables) - Pension Plans, Defined Benefit

12 Months Ended

Dec. 31, 2018

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Net periodic pension (benefit) cost included the following components:



	Successor						Predecessor
	Year Ended December 31, 2018			April 2 through December 31, 2017			January 1 through April 1, 2017			Year Ended December 31, 2016
	(Dollars in millions)
Service cost for benefits earned	$	2.3		$	1.6		$	0.6		$	2.5
Interest cost on projected benefit obligation	31.4			28.0			9.7			41.5
Expected return on plan assets	(42.8		)	(33.5		)	(11.0		)	(45.3		)
Amortization of prior service cost	—			—			0.1			0.3
Amortization of net actuarial losses	—			—			6.3			24.7
Settlement charge	—			2.1			—			—
Net actuarial loss (gain)	4.2			(23.5		)	—			—
Net periodic pension (benefit) cost	$	(4.9	)	$	(25.3	)	$	5.7		$	23.7

Amounts recognized in accumulated other comprehensive loss

The following includes pre-tax amounts recorded in “Accumulated other comprehensive income”:



	Predecessor
	January 1 through April 1, 2017			Year Ended December 31, 2016
	(Dollars in millions)
Net actuarial loss arising during period	$	—		$	6.6
Amortization:
Net actuarial loss	(6.3		)	(24.7		)
Prior service cost	(0.1		)	(0.3		)
Total recorded in “Accumulated other comprehensive income”	$	(6.4	)	$	(18.4	)

Summary of change in benefit obligation, change in plan assets and funded status

The following summarizes the change in benefit obligation, change in plan assets and funded status of the Pension Plans:



	Successor						Predecessor
	Year Ended December 31, 2018			April 2 through December 31, 2017			January 1 through April 1, 2017
	(Dollars in millions)
Change in benefit obligation:
Projected benefit obligation at beginning of period	$	874.6		$	936.4		$	959.3
Service cost	2.3			1.6			0.6
Interest cost	31.4			28.0			9.7
Benefits paid	(55.1		)	(45.3		)	(15.0		)
Actuarial (gain) loss	(57.3		)	25.3			—
Settlement	—			(71.4		)	—
Fresh start reporting adjustments	—			—			(18.2		)
Projected benefit obligation at end of period	795.9			874.6			936.4
Change in plan assets:
Fair value of plan assets at beginning of period	776.6			783.1			773.0
Actual return on plan assets	(18.7		)	80.1			25.1
Employer contributions	62.0			30.1			—
Benefits paid	(55.1		)	(45.3		)	(15.0		)
Settlement	—			(71.4		)	—
Fair value of plan assets at end of period	764.8			776.6			783.1
Funded status at end of period	$	(31.1	)	$	(98.0	)	$	(153.3	)
Amounts recognized in the consolidated balance sheets:
Noncurrent obligation (included in “Other noncurrent liabilities”)	$	(31.1	)	$	(98.0	)	$	(153.3	)
Net amount recognized	$	(31.1	)	$	(98.0	)	$	(153.3	)

Weighted-average assumptions used to determine benefit obligations

The weighted-average assumptions used to determine the benefit obligations as of the end of each year were as follows:



	December 31,
	2018		2017
Discount rate	4.35	%	3.70	%
Measurement date	December 31, 2018		December 31, 2017

Weighted-average assumptions used to determine net periodic benefit cost

The weighted-average assumptions used to determine net periodic pension (benefit) cost during each period were as follows:



	Successor				Predecessor
	Year Ended December 31, 2018		April 2 through December 31, 2017		January 1 through April 1, 2017		Year Ended December 31, 2016
Discount rate	3.70	%	4.10	%	4.15	%	4.55	%
Expected long-term return on plan assets	5.65	%	5.90	%	5.90	%	6.00	%
Measurement date	December 31, 2017		April 1, 2017		December 31, 2016		December 31, 2015

Fair value of assets in the Master Trust by category and by fair value valuation hierarchy

The following tables present the fair value of assets in the Master Trust by asset category and by fair value hierarchy:



	December 31, 2018
	Level 1		Level 2		Level 3		Total
	(Dollars in millions)
Corporate bonds	$	—	$	466.1	$	—	$	466.1
U.S. government securities	181.5		17.4		—		198.9
International government securities	—		12.4		—		12.4
Commercial paper	—		2.1		—		2.1
Cash funds	38.4		—		—		38.4
Real estate interests	—		—		6.2		6.2
Total assets at fair value	$	219.9	$	498.0	$	6.2	724.1

Assets measured at net asset value practical expedient ⁽¹⁾
Private mutual funds							40.7
Total plan assets							$	764.8



	December 31, 2017
	Level 1		Level 2		Level 3		Total
	(Dollars in millions)
Mutual funds	$	108.0	$	—	$	—	$	108.0
Corporate bonds	—		291.1		—		291.1
U.S. government securities	7.5		21.8		—		29.3
International government securities	—		17.7		—		17.7
Cash funds	30.8		—		—		30.8
Real estate interests	—		—		11.8		11.8
Total assets at fair value	$	146.3	$	330.6	$	11.8	488.7

Assets measured at net asset value practical expedient ⁽¹⁾
Private mutual funds							180.4
Common collective trusts							107.5
							287.9
Total plan assets							$	776.6


⁽¹⁾	In accordance with Accounting Standards Update 2015-07, investments that are measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the total value of assets of the plans.

Summary of changes in the fair value of the Master Trust's Level 3 investments

The table below sets forth a summary of changes in the fair value of the Master Trust’s Level 3 investments:



	Successor						Predecessor
	Year Ended December 31, 2018			April 2 through December 31, 2017			January 1 through April 1, 2017
	(Dollars in millions)
Balance, beginning of period	$	11.8		$	13.8		$	14.1
Realized gains	2.6			—			0.6
Unrealized (losses) gains relating to investments still held at the reporting date	(2.6		)	2.2			(0.6		)
Purchases, sales and settlements, net	(5.6		)	(4.2		)	(0.3		)
Balance, end of period	$	6.2		$	11.8		$	13.8

Summary of estimated future benefit payments

The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid in connection with the Company’s benefit obligation:



	Pension Benefits
	(Dollars in millions)
2019	$	56.8
2020	58.4
2021	59.4
2022	58.9
2023	58.2
Years 2024-2028	274.5