NET (LOSS) INCOME ATTRIBUTABLE TO COTY INC. PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net (loss) income attributable to Coty Inc.	$ (21.1)	$ (960.6)	$ 31.2	$ (972.7)
Weighted-average common shares outstanding:
Weighted-average common shares outstanding—Basic (in shares)	758.1	751.1	756.1	751.0
Effect of dilutive stock options and Series A/A-1 Preferred Stock (in shares)	0.0	0.0	1.5	0.0
Effect of restricted stock and RSUs (in shares)	0.0	0.0	3.6	0.0
Weighted-average common shares outstanding—Diluted (in shares)	758.1	751.1	761.2	751.0
Net (loss) income attributable to Coty Inc. per common share:
Basic (in dollars per share)	$ (0.03)	$ (1.28)	$ 0.04	$ (1.30)
Diluted (in dollars per share)	$ (0.03)	$ (1.28)	$ 0.04	$ (1.30)
Outstanding Stock Options, Series A and A-1 Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)			24.8
Restricted Share Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)			2.9