STOCK-BASED COMPENSATION (Summary of Stock-based Compensation Expense Liability and Equity Classified Awards Included in Consolidated Statements of Operations) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 19.2	$ 26.5	$ 70.5	$ 93.0
Operating costs
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	2.1	2.1	7.6	8.7
Selling, general and administrative expenses
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	17.1	24.4	62.9	84.3
Part A restricted stock units
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	16.8	17.5	58.4	57.6
Part B restricted stock units
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	1.9	8.6	10.6	24.3
Part C restricted stock units
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 0.5	$ 0.4	$ 1.5	1.0
CII
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense				$ 10.1