Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2018	Jun. 30, 2018
Statement of Financial Position [Abstract]
Allowance for doubtful accounts - trade receivables - Current	$ 52.2	$ 51.3
Allowance for doubtful accounts - trade receivables - Long-term	$ 0.6	$ 0.5
Preferred stock, par value (in US$ per share)	$ 1.0	$ 1.00
Preferred stock, shares authorized (in shares)	300,000.0	300,000.0
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	1,000,000,000.0
Common stock, shares issued (in shares)	638,700,000	638,700,000
Common stock, shares outstanding (in shares)	438,200,000	438,800,000
Treasury stock, (in shares)	200,500,000	199,900,000
Short-term Marketable Securities Under Reverse Repurchase Agreements	$ 123.8	$ 0.0
Long-term Marketable Securities Under Reverse Repurchase Agreements	328.6	0.0
Cash And Cash Equivalents Under Reverse Repurchase Agreements	$ 0.6	$ 0.0