Shareowners' Equity (Deficit) - Schedule of Changes in Accumulated Other Comprehensive Income (Loss) by Component (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Beginning balance		$ 1.2	$ (159.7)
Reclassifications, net			6.2
Unrealized gain on cash flow hedges arising during the period, net		0.0	0.6
Foreign currency translation gain		1.8	1.0
Ending balance		3.0	(151.9)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Beginning balance		2.6	(138.8)
Reclassifications, net	[1]		4.4
Unrealized gain on cash flow hedges arising during the period, net			0.0
Foreign currency translation gain		0.0	0.0
Ending balance		2.6	(134.4)
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Beginning balance		0.0	(19.7)
Reclassifications, net	[2]		1.8
Unrealized gain on cash flow hedges arising during the period, net	[3]		0.6
Foreign currency translation gain		0.0	0.0
Ending balance		0.0	(17.3)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Beginning balance		(1.4)	(1.2)
Reclassifications, net			0.0
Unrealized gain on cash flow hedges arising during the period, net			0.0
Foreign currency translation gain		1.8	1.0
Ending balance		$ 0.4	$ (0.2)

[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 (benefit) expense" on the Condensed Consolidated Statements of Operations. See Note 8 for further disclosures.

[2] These reclassifications are reported within "Interest expense" on the Condensed Consolidated Statements of Operations when the hedged transactions impact earnings.

[3] The unrealized gain, net on cash flow hedges represents the change in the fair value of the derivative instruments that occurred during the period, net of tax.