INCOME TAXES - Reconciliation of Federal statutory tax rate to effective tax rate (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Income (loss) before income taxes	$ (152.5)	$ (658.0)	$ 138.8
(Benefit) provision for income taxes at statutory rate	(42.8)	(230.3)	48.5
State and local taxes—net of federal benefit	9.9	(15.0)	(8.3)
Foreign tax differentials	(21.9)	53.3	(50.8)
Change in valuation allowances	8.6	(108.2)	(7.6)
Change in unrecognized tax benefit	(24.8)	25.6	45.8
U.S. audit settlement, net	0.0	0.0	(83.2)
Tax Act	41.0	0.0	0.0
Permanent differences—net	(8.5)	1.2	4.7
Amortization on intercompany sale	5.4	5.7	5.7
Other	8.4	8.2	4.8
Benefit for income taxes	$ (24.7)	$ (259.5)	$ (40.4)
Effective income tax rate	16.20%	39.40%	(29.10%)