Assets held at the reporting date.

No definition available.

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- Definition

Defined benefit plan actual return on plan assets unrealized during period.

+ References

No definition available.

+ Details

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- Definition

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from actual return (loss) on assets still held.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(5)(iv)(02)(A)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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- Definition

Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

+ Details

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- Definition

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from purchases, sales and settlements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(5)(iv)(02)(B)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

+ Details

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- Details

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Pension and Savings Plans Changes in the Fair Value of Master Trust's Level 3 Investments (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Apr. 01, 2017	Dec. 31, 2017	Dec. 31, 2016
Predecessor \| Real Estate Investment [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period	$ 14.1
Assets Held At Reporting Date:
Fair value of plan assets at end of period			$ 14.1
Predecessor \| Level 3 [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period	14.1	$ 13.8	23.0
Assets Held At Reporting Date:
Realized gains	0.6		1.8
Unrealized gains relatng to investments still held at the reporting date	(0.6)		0.2
Purchases, sales and settlements, net	(0.3)		(10.9)
Fair value of plan assets at end of period	13.8		14.1
Predecessor \| Level 3 [Member] \| Real Estate Investment [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period	14.1
Assets Held At Reporting Date:
Fair value of plan assets at end of period			14.1
Predecessor \| Pension Plans, Defined Benefit [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period	773.0		757.3
Assets Held At Reporting Date:
Fair value of plan assets at end of period			$ 773.0
Successor
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period		0.0
Assets Held At Reporting Date:
Fair value of plan assets at end of period	0.0	0.0
Successor \| Real Estate Investment [Member]
Assets Held At Reporting Date:
Fair value of plan assets at end of period		11.8
Successor \| Level 3 [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period		13.8
Assets Held At Reporting Date:
Realized gains		0.0
Unrealized gains relatng to investments still held at the reporting date		2.2
Purchases, sales and settlements, net		(4.2)
Fair value of plan assets at end of period	13.8	11.8
Successor \| Level 3 [Member] \| Real Estate Investment [Member]
Assets Held At Reporting Date:
Fair value of plan assets at end of period		11.8
Successor \| Pension Plans, Defined Benefit [Member]
Summary of changes in the fair value of the Master Trust's investments
Fair value of plan assets at beginning of period		783.1
Assets Held At Reporting Date:
Fair value of plan assets at end of period	$ 783.1	$ 776.6