Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2020	Jun. 30, 2020
Statement of Financial Position [Abstract]
Long-term marketable securities under reverse repurchase agreements		$ 13.6
Allowance for doubtful accounts - trade receivables - Current	$ 89.1	92.5
Allowance for doubtful accounts - trade receivables - Long-term	$ 0.6	$ 0.5
Preferred stock, par value (in US$ per share)	$ 1.00	$ 1.00
Preferred stock, shares authorized (in shares)	300,000	300,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in US$ per share)	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	1,000,000,000.0	1,000,000,000.0
Common stock, shares issued (in shares)	638,700,000	638,700,000
Common stock, shares outstanding (in shares)	429,300,000	429,900,000
Treasury stock, (in shares)	209,400,000	208,900,000