Shareowners' Deficit - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Beginning balance				$ (173.7)
Reclassifications, net				7.0
Unrealized loss on cash flow hedge arising during the period, net		$ (1.5)	$ 0.0	(1.5)	$ 0.0
Foreign currency loss		(2.5)	$ 0.0	(4.3)	$ 0.0
Ending balance		(172.5)		(172.5)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Beginning balance				(173.1)
Reclassifications, net	[1]			7.0
Unrealized loss on cash flow hedge arising during the period, net				0.0
Foreign currency loss				0.0
Ending balance		(166.1)		(166.1)
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest [Member]
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Beginning balance				0.0
Reclassifications, net				0.0
Unrealized loss on cash flow hedge arising during the period, net	[2]			(1.5)
Foreign currency loss				0.0
Ending balance		(1.5)		(1.5)
Accumulated Foreign Currency Adjustment Attributable to Parent
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Beginning balance				(0.6)
Reclassifications, net				0.0
Unrealized loss on cash flow hedge arising during the period, net				0.0
Foreign currency loss				(4.3)
Ending balance		$ (4.9)		$ (4.9)

[1] These reclassifications are included in the other components of net periodic pension and postretirement benefit plans expense and represent amortization of prior service benefit and actuarial loss, net of tax (see Note 9 for additional details). The other components of net periodic pension and postretirement benefit plans expense are recorded in "Other components of pension and postretirement benefit plans expense" on the Condensed Consolidated Statements of Operations. See Note 9 for further disclosures.

[2] In June 2018, the Company entered into an interest rate swap agreement to minimize its exposure to interest rate fluctuations on variable rate debt. The interest rate swap is considered a derivative instrument and qualifies for cash flow hedge accounting in accordance with ASC 815. The unrealized loss on cash flow hedge represents the change in the fair value of the derivative instrument that occurred during the period, net of tax. This unrealized loss is recorded in "Other noncurrent liabilities" on the Condensed Consolidated Balance Sheets.