INCOME TAXES - Expirations of Tax Loss Carry Forwards (Details) $ in Millions	Jun. 30, 2020 USD ($)
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	$ 2,075.5
Tax Year 2020
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	11.1
Tax Year 2021
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	3.5
Tax Year 2022
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	5.6
Tax Year 2023
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	7.1
Tax Year 2024 and Thereafter
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	2,048.2
United States
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	645.5
United States | Tax Year 2020
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	0.0
United States | Tax Year 2021
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	0.0
United States | Tax Year 2022
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	0.0
United States | Tax Year 2023
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	0.0
United States | Tax Year 2024 and Thereafter
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	645.5
Western Europe
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	1,246.9
Western Europe | Tax Year 2020
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	0.0
Western Europe | Tax Year 2021
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	0.0
Western Europe | Tax Year 2022
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	0.0
Western Europe | Tax Year 2023
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	0.1
Western Europe | Tax Year 2024 and Thereafter
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	1,246.8
Rest of World
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	183.1
Rest of World | Tax Year 2020
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	11.1
Rest of World | Tax Year 2021
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	3.5
Rest of World | Tax Year 2022
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	5.6
Rest of World | Tax Year 2023
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	7.0
Rest of World | Tax Year 2024 and Thereafter
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	$ 155.9