Earnings per Share (EPS) and Common Stock - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Earnings Per Share And Common Stock [Abstract]
Common stock, shares authorized	500,000,000		500,000,000		500,000,000
Stock repurchase program, authorized amount	$ 1,000,000,000		$ 1,000,000,000
Repurchases of common stock (in shares)	43,000		1,046,000
Stock repurchased during period, value	$ 5,300,000	$ 0	$ 125,000,000.0	$ 0