Discontinued Operations (Schedule of Operating Results) (Details) - USD ($) $ in Millions			3 Months Ended
		Jan. 03, 2017	Dec. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (Loss) from Discontinued Operations, net of tax			$ (1.0)	$ 48.2
Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales				254.8
Cost of sales				185.6
Selling and administrative				20.6
Research and development				5.1
Other income (expense), net				(0.1)
Operating Income (Loss)				43.4
Equity affiliates’ income				0.3
Income (Loss) Before Taxes				43.7
Income tax provision	[1]			(51.6)
Income (Loss) From Operations of Discontinued Operations, net of tax				95.3
Loss on Disposal, net of tax				(47.1)
Income (Loss) from Discontinued Operations, net of tax			$ (1.0)	48.2
Performance Materials Division (PMD) | Discontinued Operations, Held-for-sale or Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales				254.8
Cost of sales				179.0
Selling and administrative				20.4
Research and development				5.1
Other income (expense), net				(0.4)
Operating Income (Loss)				49.9
Equity affiliates’ income				0.3
Income (Loss) Before Taxes				50.2
Income tax provision	[1]			(50.5)
Income (Loss) From Operations of Discontinued Operations, net of tax				100.7
Loss on Disposal, net of tax		$ 1,828.0		0.0
Income (Loss) from Discontinued Operations, net of tax				100.7
Valuation allowance adjustment effect on income tax provision				69.0
Energy-from-Waste (EfW) | Discontinued Operations, Held-for-sale or Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales	[2]			0.0
Cost of sales	[2]			6.6
Selling and administrative	[2]			0.2
Research and development	[2]			0.0
Other income (expense), net	[2]			0.3
Operating Income (Loss)	[2]			(6.5)
Equity affiliates’ income	[2]			0.0
Income (Loss) Before Taxes	[2]			(6.5)
Income tax provision	[1],[2]			(1.1)
Income (Loss) From Operations of Discontinued Operations, net of tax	[2]			(5.4)
Loss on Disposal, net of tax	[2]			(47.1)
Income (Loss) from Discontinued Operations, net of tax	[2]			$ (52.5)

[1] As a result of the expected gain on sale of PMD, we released valuation allowances related to capital loss and net operating loss carryforwards primarily during the first quarter of 2017 that favorably impacted our income tax provision within discontinued operations by approximately $69.

[2] The loss from operations of discontinued operations for EfW primarily relates to land lease obligations, administrative costs, and costs incurred for ongoing project exit activities.