CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
NET LOSS	$ (144.1)	$ (20.9)	$ (333.1)	$ (39.3)
OTHER COMPREHENSIVE INCOME (LOSS):
Net changes in pension and other postretirement plan assets and benefit obligations recognized in other comprehensive income, net of income tax expense of $0 for both the three months ended September 30, 2018 and 2017, and $4.2 and $0 for the nine months ended September 30, 2018 and 2017, respectively (see Note 5).	0.0	0.0	15.9	0.0
Net reclassification adjustment for amounts recognized in net loss as a component of net periodic benefit cost, net of income tax (benefit) expense of ($0.1) and $0.5 for the three months ended September 30, 2018 and 2017, respectively, and $1.1 and $1.5 for the nine months ended September 30, 2018, and 2017, respectively (see Note 5 and 9).	(0.7)	1.0	4.0	2.7
Total Other Comprehensive Income	(0.7)	1.0	19.9	2.7
COMPREHENSIVE LOSS	$ (144.8)	$ (19.9)	$ (313.2)	$ (36.6)