SHARE-BASED COMPENSATION PLANS - Share-based Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 15.2	$ 33.4	$ 29.0
Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	16.9	31.6	20.0
Liability Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	(2.1)	(1.0)	4.6
Fringe
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 0.4	$ 2.8	$ 4.4