COMMON STOCK - Common stock outstanding (Details) - shares	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Common Class A
Increase (Decrease) in Stockholders' Equity
Balance at the beginning of the period (in shares)	221,564,500	224,093,800	224,341,200
Acquisition of treasury stock (in shares)	(4,665,000.0)	(10,986,700)	(6,045,400)
Conversion of Class B to Class A (in shares)	4,302,400	3,513,900	710,600
Stock-based compensation (in shares)	4,088,300	4,943,500	5,087,400
Balance at the end of the period (in shares)	225,290,200	221,564,500	224,093,800
Common Class B
Increase (Decrease) in Stockholders' Equity
Balance at the beginning of the period (in shares)	139,537,814	143,051,700	143,762,300
Conversion of Class B to Class A (in shares)	(4,302,400)	(3,513,900)	(710,600)
Balance at the end of the period (in shares)	135,235,429	139,537,814	143,051,700