CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 167.0	$ 188.5	$ 47.0
Other comprehensive (loss) income, net of tax
Cumulative adjustment upon adoption of ASU 2017-12 reclassified to reinvested earnings	(1.0)	0.0	0.0
Pension and postretirement (losses) benefits, net of tax of $23.2, $(26.3) and $(27.3), respectively	(72.9)	78.6	45.3
Net (loss) gain on derivative instruments, net of tax of $13.3, $(13.7) and $(11.8), respectively	(37.6)	26.1	19.5
Marketable securities gain, net of tax of $0.0, $0.0 and $0.0, respectively	0.3	0.0	0.0
Foreign currency translation	(0.8)	(1.4)	2.0
Other comprehensive (loss) income, net of tax	(112.0)	103.3	66.8
Comprehensive income, net of tax	$ 55.0	$ 291.8	$ 113.8