Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2020	Jun. 30, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 7.5	$ 9.8
Preferred stock, shares authorized (in shares)	25,000,000.0	25,000,000.0
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	650,000,000.0	650,000,000.0
Common stock, shares issued (in shares)	154,500,000	154,500,000
Common stock, shares outstanding (in shares)	115,600,000	115,100,000
Treasury stock, shares (in shares)	38,800,000	39,300,000