Earnings per Share (EPS) and Common Stock - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022	Sep. 30, 2022
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	$ 1,000.0		$ 1,000.0
Repurchases of common stock	0	43,000	0	1,046,000
Stock Repurchased During Period, Value		$ 5.3		$ 125.0

Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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