RESTRUCTURING CHARGES (Details 2) - USD ($) $ in Millions	3 Months Ended						9 Months Ended		66 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Accrued restructuring costs	$ 14.6			$ 2.5			$ 14.6	$ 2.5	$ 14.6	$ 3.5	$ 3.1
Restructuring charges	3.6	$ 14.0	$ 6.9	1.3	$ 1.7	$ 1.7	24.5	4.7	267.9
Amounts utilized							(13.4)	(5.3)
Employee severance and related benefit costs
Restructuring Cost and Reserve [Line Items]
Accrued restructuring costs	8.6			0.0			8.6	0.0	8.6	1.8	0.0
Restructuring charges	0.2	10.1	0.0	0.0	0.0	0.1			19.1
Amounts utilized							(3.5)	(0.1)
Lease and other contract termination costs
Restructuring Cost and Reserve [Line Items]
Accrued restructuring costs	6.0			2.5			6.0	2.5	6.0	1.7	3.1
Restructuring charges	0.5	0.5	4.6	0.3	0.0	0.1			47.8
Amounts utilized							(1.3)	(1.0)
Facility exit costs
Restructuring Cost and Reserve [Line Items]
Accrued restructuring costs	0.0			0.0			0.0	0.0	0.0	$ 0.0	$ 0.0
Restructuring charges	$ 2.9	$ 3.4	$ 2.3	$ 1.0	$ 1.7	$ 1.5			$ 62.3
Amounts utilized							$ (8.6)	$ (4.2)