Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions		Sep. 30, 2021	Jun. 30, 2021
Statement of Financial Position [Abstract]
Allowance for doubtful accounts - trade receivables - Current		$ 76.7	$ 79.6
Allowance for doubtful accounts - trade receivables - Long-term		$ 0.3	$ 0.3
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	1,000,000,000
Common stock, shares issued (in shares)		638,700,000	638,700,000
Common stock, shares outstanding (in shares)		422,000,000.0	423,700,000
Treasury stock, (in shares)		216,700,000	215,000,000.0
Obligations under reverse repurchase agreements	[1]	$ 45.8	$ 23.5
Long-term marketable securities under reverse repurchase agreements			$ 23.5

[1] As of September 30, 2021, $45.8 million of short-term marketable securities have been pledged as collateral under the Company's reverse repurchase agreements. As of June 30, 2021, $23.5 million of long-term marketable securities have been pledged as collateral under the Company's reverse repurchase agreements (see Note 9).