Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2016	Jun. 30, 2015
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 2.3	$ 3.8
Preferred stock, shares authorized	25,000,000.0	25,000,000.0
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	650,000,000	650,000,000
Common stock, shares issued	154,500,000	154,500,000
Common stock, shares outstanding	118,300,000	118,200,000
Treasury stock, shares	36,200,000	36,300,000