CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 41.2	$ 31.5
Other comprehensive income (loss), net of tax
Cumulative adjustment upon adoption of ASU 2017-12 reclassified to reinvested earnings	0.0	(1.0)
Pension and postretirement benefits, net of tax of $(1.0) and $(0.5), respectively	3.0	1.7
Net gain (loss) on derivative instruments, net of tax of $(8.5) and $8.7, respectively	26.7	(23.0)
Marketable securities gain, net of tax of $0.0 and $0.0, respectively	0.0	0.3
Foreign currency translation	(5.5)	0.7
Other comprehensive income (loss), net of tax	24.2	(21.3)
Comprehensive income	$ 65.4	$ 10.2