Common and Preferred Stock (Details) - $ / shares shares in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Class of Stock Disclosures [Abstract]
Shares of common stock reserved for issuance under stock-based compensation plans	13.7
Common shares repurchased	5.3	16.4
Treasury shares re-issued	3.1	3.4
Shares of preferred stock authorized	5.4	5.4
Par value of preferred stocked authorized	$ 2.50	$ 2.50
Shares of preferred stock issued	0.0	0.0