CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 38.8	$ 35.5	$ 80.0	$ 67.0
Other comprehensive (loss) income, net of tax
Cumulative adjustment upon adoption of ASU 2017-12 reclassified to reinvested earnings	0.0	0.0	0.0	(1.0)
Pension and postretirement benefits, net of tax of $(1.0), $(0.5), $(2.0) and $(1.0), respectively	3.0	1.7	6.0	3.4
Net (loss) gain on derivative instruments, net of tax of $6.1, $4.9, $(2.4) and $13.6, respectively	(19.1)	(15.4)	7.6	(38.4)
Marketable securities gain, net of tax of $0.0, $0.0, $0.0 and $0.0, respectively	0.0	0.0	0.0	0.3
Foreign currency translation	7.4	(2.7)	1.9	(2.0)
Other comprehensive (loss) income, net of tax	(8.7)	(16.4)	15.5	(37.7)
Comprehensive income	$ 30.1	$ 19.1	$ 95.5	$ 29.3