CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 11.3	$ 58.7	$ 132.8
Other comprehensive (loss) income, net of tax
Pension and postretirement benefits (loss) gain, net of tax of $52.8, $12.0 and $(22.1), respectively	(87.5)	(20.1)	36.9
Net gain (loss) on derivative instruments, net of tax of $(4.0), $21.7 and $(29.5), respectively	6.7	(36.1)	49.1
Unrealized gain on marketable securities, net of tax of $0.0, $0.0 and $0.0, respectively	0.0	0.1	0.0
Foreign currency translation	(0.9)	(26.9)	4.5
Other comprehensive (loss) income, net of tax	(81.7)	(83.0)	90.5
Comprehensive (loss) income, net of tax	$ (70.4)	$ (24.3)	$ 223.3