FAIR VALUE MEASUREMENTS AND THE FAIR VALUE OPTION - Schedule of Fair Value Measurements (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unconsolidated investments	$ 1,107.4	$ 662.6
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unconsolidated investments	1,107.4	662.2
Assets (liabilities), fair value disclosure	1,072.7	646.4
Recurring [Member] | Currency Derivative Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net currency derivative contracts	(34.7)	(15.8)
Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unconsolidated investments	0.0	0.0
Assets (liabilities), fair value disclosure	0.0
Recurring [Member] | Level 1 [Member] | Currency Derivative Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net currency derivative contracts	0.0	0.0
Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unconsolidated investments	0.0	0.0
Assets (liabilities), fair value disclosure	(34.7)	(15.8)
Recurring [Member] | Level 2 [Member] | Currency Derivative Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net currency derivative contracts	(34.7)	(15.8)
Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unconsolidated investments	1,107.4	662.2
Assets (liabilities), fair value disclosure	1,107.4	662.2
Recurring [Member] | Level 3 [Member] | Currency Derivative Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net currency derivative contracts	$ 0.0	$ 0.0