Shareowners' Deficit - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Beginning balance				$ (173.7)
Reclassifications, net				10.5
Unrealized gain on cash flow hedge arising during the period, net		$ 1.6	$ 0.0	0.1	$ 0.0
Foreign currency loss		1.7	$ 0.1	(2.6)	$ 0.1
Ending balance		(165.7)		(165.7)
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]			10.5
Unrealized gain on cash flow hedge arising during the period, net				0.0
Foreign currency loss				0.0
Ending balance		(162.6)		(162.6)
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 gain on cash flow hedge arising during the period, net	[2]			0.1
Foreign currency loss				0.0
Ending balance		0.1		0.1
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 gain on cash flow hedge arising during the period, net				0.0
Foreign currency loss				(2.6)
Ending balance		$ (3.2)		$ (3.2)

[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. 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 10 for further disclosures.

[2] The unrealized gain 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 gain is recorded in "Other noncurrent assets" and "Other current liabilities" on the Condensed Consolidated Balance Sheets. See Note 7 for further disclosures.