NET INCOME (LOSS) ATTRIBUTABLE TO COTY INC. PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2023
Amounts attributable to Coty Inc.:
Net (loss) income	$ (367.9)	$ 89.4	$ 508.2
Convertible Series B Preferred Stock dividends	(13.2)	(13.2)	(13.2)
Net (loss) income attributable to common stockholders	$ (381.1)	$ 76.2	$ 495.0
Weighted-average common shares outstanding:
Weighted-average common shares outstanding—Basic (in shares)	870.9	874.4	849.0
Effect of dilutive stock options and Series A Preferred Stock (in shares)	0.0	0.1	0.0
Effect of restricted stock, PRSUs and RSUs (in shares)	0.0	8.9	13.8
Effect of Convertible Series B Preferred Stock (in shares)	0.0	0.0	23.7
Effect of Forward Repurchase Contracts	0.0	0.0	0.0
Weighted-average common shares and common share equivalents outstanding—Diluted (in shares)	870.9	883.4	886.5
Earnings (losses) per common share
(Losses) earnings per common share - basic (in dollars per share)	$ (0.44)	$ 0.09	$ 0.58
(Losses) earnings per common share - diluted (in dollars per share)	$ (0.44)	$ 0.09	$ 0.57
Convertible Series B Preferred Stock dividends	$ 13.2	$ 13.2	$ 13.2
Antidilutive​ fair market value adjustments	$ 248.1	$ 73.4	$ (101.8)
Share-Based Payment Arrangement, Option and Series A Preferred Stock
Earnings (losses) per common share
Anti-dilutive shares (in shares)	3.5	2.8	4.8
Restricted Stock Units
Earnings (losses) per common share
Anti-dilutive shares (in shares)	11.6	1.0	3.2
Convertible Series B Preferred Stock
Earnings (losses) per common share
Anti-dilutive shares (in shares)	0.0	0.0	23.7