PREPAID EXPENSES AND OTHER CURRENT ASSETS (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Schedule Of Prepaid Expenses And Other Current Assets [Line Items]
Prepaid expenses and other current assets	$ 312.6	$ 206.5
Prepaid expenses and other current assets
Schedule Of Prepaid Expenses And Other Current Assets [Line Items]
Prepaid expenses	100.3	69.5
Available-for-sale securities	54.4	0.0
Deposits	37.2	39.4
Fair value of derivatives	3.9	14.1
Other current assets	$ 116.8	$ 83.5