Weighted-Average Common Shares - Schedule Of Basic And Diluted Earnings Per Common Share Reconciliation (Details) - shares shares in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Basic shares outstanding (in shares)	574.2	592.9	598.1
Dilutive shares (in shares)	3.1	3.4	3.7
Diluted shares outstanding (in shares)	577.3	596.3	601.8