INCOME TAXES - Reconciliation of Federal Statutory Tax Rate to Effective Tax Rate (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income (loss) before income taxes	$ (3,778.1)	$ (152.5)	$ (658.0)
Benefit for income taxes at statutory rate	(793.4)	(42.8)	(230.3)
State and local taxes—net of federal benefit	(30.7)	9.9	(15.0)
Foreign tax differentials	58.8	(21.9)	53.3
Change in valuation allowances	(6.7)	8.6	(108.2)
Change in unrecognized tax benefit	43.4	(24.8)	25.6
Tax Act	0.0	41.0	0.0
Permanent differences—net	1.8	(8.5)	1.2
Amortization on intercompany sale	0.0	5.4	5.7
Goodwill impairment	693.0	0.0	0.0
Other	25.3	8.4	8.2
Benefit for income taxes	$ (8.5)	$ (24.7)	$ (259.5)
Effective income tax rate	0.20%	16.20%	39.40%