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Pension and Savings Plans Pre-tax Amounts Recorded to Accumulated Other Comprehensive Loss (Details) - Pension Plan [Member] - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Apr. 01, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Predecessor
Amounts recognized in accumulated other comprehensive loss
Net actuarial loss arising during period	$ 0.0		$ 6.6	$ 30.6
Amortization:
Net actuarial loss	6.3		24.7	39.6
Prior service cost	(0.1)		(0.3)	(1.0)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax	0.0		0.0	0.0
Total recorded in other comprehensive (income) loss	$ (6.4)		$ (18.4)	$ (10.0)
Successor
Amortization:
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax		$ 23.5

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Amount, before tax, of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) of defined benefit plan.

+ References

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-Publisher FASB
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Amount, before tax, after reclassification adjustment, of (increase) decrease in accumulated other comprehensive income for defined benefit plan.

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Amount, before tax, of gain (loss) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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