Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2021	Jun. 30, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts - trade receivables - Current	$ 83.1	$ 92.5
Allowance for doubtful accounts - trade receivables - Long-term	$ 0.5	$ 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)	426,000,000.0	429,900,000
Treasury stock, (in shares)	212,700,000	208,900,000
Long-term marketable securities under reverse repurchase agreements		$ 13.6