Shareowners' Deficit - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Beginning balance		$ (173.7)
Reclassifications, net		3.5
Foreign currency loss		(1.8)	$ 0.0
Ending balance		(172.0)
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]	3.5
Foreign currency loss		0.0
Ending balance		(169.6)
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
Foreign currency loss		(1.8)
Ending balance		$ (2.4)

[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 in accordance with ASU 2017-07, which the Company retrospectively adopted effective January 1, 2018.