VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Restructuring charges (benefits) and other costs (benefits)	$ 126.1	$ 19.8	$ 23.7	$ 10.9	$ 23.7	$ 6.2	$ 20.3	$ 10.0	$ 180.5	$ 60.2	$ 77.4
Allowance for doubtful accounts receivable
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period				129.3				122.9	129.3	122.9	77.6
Charged to Costs and Expenses									162.4	221.9	190.5
Charged to Revenue									0.0	0.0	0.0
Deductions									(198.7)	(215.5)	(145.2)
Balance at End of Period	93.0				129.3				93.0	129.3	122.9
Refund liability
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period				9.3					9.3
Charged to Costs and Expenses									0.0
Charged to Revenue									172.3
Deductions									(169.3)
Balance at End of Period	12.3				9.3				12.3	9.3
Allowance for sales returns
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period				9.3				8.2	9.3	8.2	9.1
Charged to Costs and Expenses										0.0	0.0
Charged to Revenue										197.9	186.9
Deductions										(196.8)	(187.8)
Balance at End of Period					9.3					9.3	8.2
Allowance for inventory obsolescence
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period				61.3				58.4	61.3	58.4	71.3
Charged to Costs and Expenses									113.5	36.7	36.5
Charged to Revenue									0.0	0.0	0.0
Deductions									55.2	(33.8)	(49.4)
Balance at End of Period	230.0				61.3				230.0	61.3	58.4
Deferred tax asset valuation allowance
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period				$ 3,217.6				$ 3,296.0	3,217.6	3,296.0	2,090.1
Charged to Costs and Expenses									39.9	(78.4)	1,205.9
Charged to Revenue									0.0	0.0	0.0
Deductions									0.0	0.0	0.0
Balance at End of Period	$ 3,257.5				$ 3,217.6				3,257.5	$ 3,217.6	$ 3,296.0
Inventory Write-offs
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Restructuring charges (benefits) and other costs (benefits)									$ 89.8