NET INCOME (LOSS) 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, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net (loss) income attributable to Coty Inc.	$ (960.6)	$ 109.2	$ (972.7)	$ 89.5
Weighted-average common shares outstanding:
Weighted-average common shares outstanding—basic (in shares)	751.1	749.6	751.0	749.1
Effect of dilutive stock options and Series A Preferred Stock (in shares)	0.0	1.2	0.0	1.4
Effect of restricted stock and RSUs (in shares)	0.0	1.9	0.0	2.0
Weighted-average common shares outstanding—Diluted (in shares)	751.1	752.7	751.0	752.5
Net (loss) income attributable to Coty Inc. per common share:
Basic (in usd per share)	$ (1.28)	$ 0.15	$ (1.30)	$ 0.12
Diluted (in usd per share)	$ (1.28)	$ 0.15	$ (1.30)	$ 0.12
Outstanding Stock Options and Series A 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)		15.3		13.6
Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)		2.6		4.1