CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - 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 (loss) income	$ (9.3)	$ 7.2	$ 120.2	$ 159.6
Cash flow hedges
Reclassification of net losses (gains) to net income, net of tax of $0.1 million, $ – million, $0.2 million, and $0.9 million, respectively	0.2	0.2	0.3	(0.4)
Defined benefit plans
Pension and other postretirement benefit adjustments arising during period, net of tax of $0.4 million, $ – million, $0.4 million, and $(0.1) million, respectively	0.7	0.0	0.7	(0.1)
Amortization of pension and other postretirement benefit costs included in net periodic benefit cost, net of tax of $0.6 million, $0.2 million, $1.1 million, and $0.5 million, respectively	0.9	0.5	1.6	0.8
Defined benefit plans, net	1.6	0.5	2.3	0.7
Other comprehensive income, net of tax	1.8	0.7	2.6	0.3
Comprehensive (loss) income	$ (7.5)	$ 7.9	$ 122.8	$ 159.9