SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Recently Adopted Accounting Pronouncements (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017	Jul. 01, 2018	Jun. 30, 2016
ASSETS
Property and equipment, net	$ 1,600.6	$ 1,680.8		$ 1,674.6
Deferred income taxes	146.3	107.4		108.0
Other noncurrent assets	149.7	299.5		306.4
Current liabilities:
Accrued expenses and other current liabilities	1,483.7	1,844.4		1,865.1
Deferred income taxes	652.5	842.5		841.3
Accumulated deficit	(4,541.2)	(626.2)		(644.4)
Net revenues	8,648.5	9,398.0	$ 7,650.3
Selling, general and administrative expenses	4,563.9	5,018.1	4,040.7
Net loss	(3,769.6)	(127.8)	(398.5)
Net loss attributable to Coty Inc.	$ (3,784.2)	$ (168.8)	$ (422.2)
Net loss attributable to Coty Inc. per common share:
Basic (dollars per shares)	$ (5.04)	$ (0.23)	$ (0.66)
Diluted (dollars per shares)	$ (5.04)	$ (0.23)	$ (0.66)
Decrease in prepaid expenses and other current assets	$ (577.8)	$ (603.9)
Unrecognized tax benefits	336.1	303.6	$ 257.9		$ 228.9
Cost of sales	3,306.5	3,607.8	3,028.3
Restructuring costs	44.2	173.2	374.8
Operating income	(3,471.5)	153.3	(420.9)
Other expense, net	30.9	30.1	18.5
Calculated under Revenue Guidance in Effect before Topic 606
ASSETS
Property and equipment, net		1,680.8
Deferred income taxes		107.4
Other noncurrent assets		299.5
Current liabilities:
Accrued expenses and other current liabilities		1,844.4
Deferred income taxes		842.5
Accumulated deficit		(626.2)
Net revenues	8,650.3
Selling, general and administrative expenses	4,567.3
Net loss	(3,770.9)
Net loss attributable to Coty Inc.	$ (3,785.1)
Net loss attributable to Coty Inc. per common share:
Basic (dollars per shares)	$ (5.04)
Diluted (dollars per shares)	$ (5.04)
Previously Reported
Current liabilities:
Selling, general and administrative expenses		5,009.6	4,060.0
Net loss		(127.8)	(398.5)
Net loss attributable to Coty Inc. per common share:
Cost of sales		3,608.4	3,028.5
Restructuring costs		173.2	372.2
Operating income		161.2	(437.8)
Other expense, net		38.0	1.6
Restatement Adjustment
Current liabilities:
Selling, general and administrative expenses		5,018.1	4,040.7
Net loss		(127.8)	(398.5)
Net loss attributable to Coty Inc. per common share:
Cost of sales		3,607.8	3,028.3
Restructuring costs		173.2	374.8
Operating income		153.3	(420.9)
Other expense, net		30.1	18.5
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
ASSETS
Property and equipment, net				(6.2)
Deferred income taxes				0.6
Other noncurrent assets				6.9
Current liabilities:
Accrued expenses and other current liabilities				20.7
Deferred income taxes				(1.2)
Accumulated deficit				(18.2)
Net revenues	$ 1.8
Selling, general and administrative expenses	3.4
Net loss	(1.3)
Net loss attributable to Coty Inc.	$ (0.9)
Net loss attributable to Coty Inc. per common share:
Basic (dollars per shares)	$ 0
Diluted (dollars per shares)	$ 0
Accounting Standards Update 2016-06
ASSETS
Other noncurrent assets				(120.8)
Current liabilities:
Accumulated deficit				(112.6)
Net loss attributable to Coty Inc. per common share:
Decrease in prepaid expenses and other current assets				7.6
Unrecognized tax benefits				$ 15.8
Accounting Standards Update 2017-07 | Restatement Adjustment
Current liabilities:
Selling, general and administrative expenses		8.5	(19.3)
Net loss		0.0	0.0
Net loss attributable to Coty Inc. per common share:
Cost of sales		(0.6)	(0.2)
Restructuring costs		0.0	2.6
Operating income		(7.9)	16.9
Other expense, net		$ (7.9)	$ 16.9