RESTRUCTURING COSTS - Restructuring Costs by Type (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 134.9	$ 21.5	$ 140.9	$ 37.0
Turnaround Plan
Restructuring Cost and Reserve [Line Items]
Restructuring costs	137.9	0.0	146.6	0.0
Cumulative through December 31, 2019	146.6		146.6
Global Integration Activities
Restructuring Cost and Reserve [Line Items]
Restructuring costs	(2.7)	$ 22.2	(4.4)	$ 28.7	$ 28.5	$ 106.5	$ 365.0
Cumulative through December 31, 2019	495.6		495.6
2018 Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring costs			(1.0)		16.8	68.4
Cumulative through December 31, 2019	84.2		84.2
Severance and Employee Benefits | Turnaround Plan
Restructuring Cost and Reserve [Line Items]
Cumulative through December 31, 2019	144.4		144.4
Severance and Employee Benefits | Global Integration Activities
Restructuring Cost and Reserve [Line Items]
Restructuring costs			(4.3)		(6.0)	67.5	333.9
Cumulative through December 31, 2019	391.1		391.1
Severance and Employee Benefits | 2018 Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring costs			(1.0)		15.4	63.5
Cumulative through December 31, 2019	77.9		77.9
Third-Party Contract Terminations | Turnaround Plan
Restructuring Cost and Reserve [Line Items]
Cumulative through December 31, 2019	0.1		0.1
Third-Party Contract Terminations | Global Integration Activities
Restructuring Cost and Reserve [Line Items]
Restructuring costs			0.0		4.5	19.3	22.4
Cumulative through December 31, 2019	46.2		46.2
Third-Party Contract Terminations | 2018 Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring costs			0.0		(0.1)	0.2
Cumulative through December 31, 2019	0.1		0.1
Fixed Asset Write-offs | Global Integration Activities
Restructuring Cost and Reserve [Line Items]
Restructuring costs			0.0		27.8	14.3	4.6
Cumulative through December 31, 2019	46.7		46.7
Fixed Asset Write-offs | 2018 Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring costs			0.0		0.0	1.3
Cumulative through December 31, 2019	1.3		1.3
Other Exit Costs | Turnaround Plan
Restructuring Cost and Reserve [Line Items]
Cumulative through December 31, 2019	2.1		2.1
Other Exit Costs | Global Integration Activities
Restructuring Cost and Reserve [Line Items]
Restructuring costs			(0.1)		2.2	5.4	$ 4.1
Cumulative through December 31, 2019	11.6		11.6
Other Exit Costs | 2018 Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring costs			0.0		$ 1.5	$ 3.4
Cumulative through December 31, 2019	$ 4.9		$ 4.9