Summary of Significant Accounting Policies - Shares Used in Computing Basic and Diluted Earnings Per Share (Details) - shares shares in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Accounting Policies [Abstract]
Weighted-average common shares outstanding for basic computation (in shares)	209,806	209,940	209,063
Incremental shares issuable for stock options, common stock awards and Equity Units (in shares)	0	5,881	3,063
Weighted-average common shares outstanding for diluted computation (in shares)	209,806	215,821	212,126
Antidilutive securities excluded from computation of earnings per share (in shares)	6,132	8,138	5,267