Derivatives and Hedging Activities - Schedule of Changes in AOCI Associated with Derivative Hedging Activities (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, beginning of period	$ 1,485.9	$ 1,198.6	$ 1,104.9
Cumulative adjustment upon adoption of ASU 2017-12 reclassified to reinvested earnings	(1.0)	0.0	0.0
Balances, end of period	1,520.1	1,485.9	1,198.6
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances, beginning of period	23.8	(2.3)	(21.8)
Cumulative adjustment upon adoption of ASU 2017-12 reclassified to reinvested earnings	(1.0)
Current period changes in fair value, net of tax	(32.7)	26.9	5.8
Reclassification to earnings, net of tax	(4.9)	(0.8)	13.7
Balances, end of period	$ (14.8)	$ 23.8	$ (2.3)