RESTRUCTURING CHARGES - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended	11 Months Ended	34 Months Ended	49 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2019	Dec. 31, 2020	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Payments for restructuring	$ 25.3
Restructuring and related charges	27.4
2018 Optimization Restructuring Program
Restructuring Cost and Reserve [Line Items]
Additional capital expenditures, expected cost	$ 10.0	$ 10.0	$ 10.0
Percent of restructuring charges expected to be paid in cash	85.00%	85.00%	85.00%
Payments for restructuring	$ 15.0	$ 15.8
Restructuring costs recognized to date	33.8	33.8	$ 33.8		$ 5.7
Restructuring and related charges	28.1
2018 Optimization Restructuring Program | Minimum
Restructuring Cost and Reserve [Line Items]
Expected restructuring and related charges	30.0	30.0	30.0
2018 Optimization Restructuring Program | Maximum
Restructuring Cost and Reserve [Line Items]
Expected restructuring and related charges	40.0	40.0	40.0
2018 Optimization Restructuring Program | Employee-related costs
Restructuring Cost and Reserve [Line Items]
Payments for restructuring	6.8
Restructuring costs recognized to date	16.5	16.5	16.5		4.5
Restructuring and related charges	12.0
2018 Optimization Restructuring Program | Other Costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs recognized to date	0.5	0.5	0.5		0.0
Restructuring and related charges	0.5
EA Integration Restructuring Program
Restructuring Cost and Reserve [Line Items]
Payments for restructuring	8.1		72.0
Restructuring costs recognized to date	82.6	82.6	82.6		82.2
Restructuring and related charges	0.4
EA Integration Restructuring Program | Employee-related costs
Restructuring Cost and Reserve [Line Items]
Payments for restructuring	7.7
Restructuring costs recognized to date	72.6	72.6	72.6		72.2
Restructuring and related charges	0.4
EA Integration Restructuring Program | Lease termination costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs recognized to date	5.1	5.1	5.1		$ 5.1
Restructuring and related charges	0.0
EA Integration Restructuring Program | Other Costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs recognized to date	$ 4.9	$ 4.9	$ 4.9
Scenario, Forecast | EA Integration Restructuring Program | Minimum
Restructuring Cost and Reserve [Line Items]
Payments for restructuring				$ 80.0
Scenario, Forecast | EA Integration Restructuring Program | Maximum
Restructuring Cost and Reserve [Line Items]
Payments for restructuring				$ 85.0