ACCRUED LIABILITIES (Schedule of Accrued Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Jun. 30, 2017
Accrued Liabilities, Current [Abstract]
Accrued compensation and benefits	$ 44.9	$ 38.5
Accrued property and equipment purchases	74.5	81.8
Network expense accruals	112.5	93.6
Other accrued taxes	11.8	23.1
Accrued professional fees	4.3	3.9
Other accruals	65.0	84.5
Less liabilities held for sale	(0.7)
Accrued Liabilities, Current, Total	$ 312.3	$ 325.4