CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ (76.3)	$ (92.3)	$ (131.9)	$ (52.6)
Pension and other postretirement plans adjustments:
Amortization of net actuarial loss	[1]		0.1	0.2	0.2
Amortization of prior service cost	[2]	0.1	0.8	0.6	1.7
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Tax			(0.1)	(0.1)	(0.2)
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), Tax		(0.1)	(0.5)	(0.4)	(1.0)
Other comprehensive income		0.1	0.9	0.8	1.9
Comprehensive income (loss)		$ (76.2)	$ (91.4)	$ (131.1)	$ (50.7)

[1] Presented net of income tax expense of $0.1 million during the six months ended June 30, 2015, and $0.1 million and $0.2 million during the three and six months ended June 30, 2014, respectively.

[2] Presented net of income tax expense of $0.1 million and $0.4 million during the three and six months ended June 30, 2015, respectively, and $0.5 million and $1.0 million during the three and six months ended June 30, 2014, respectively.