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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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- Definition Amount, before tax, of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) of defined benefit plan. + 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 (i) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e689-108580 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e637-108580 + Details
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