Earnings per Share (Schedule of Weighted-Average Shares Outstanding) (Details) - shares shares in Millions |
3 Months Ended | |
|---|---|---|
Dec. 31, 2022 |
Dec. 31, 2021 |
|
| Schedule Of Weighted Average Number Of Shares [Line Items] | ||
| Basic weighted-average shares outstanding (in shares) | 51.6 | 54.4 |
| Effect of dilutive securities (in shares) | 0.3 | 0.6 |
| Diluted weighted-average shares outstanding (in shares) | 51.9 | 55.0 |
| RSE and PRSE awards | ||
| Schedule Of Weighted Average Number Of Shares [Line Items] | ||
| Effect of dilutive securities (in shares) | 0.3 | 0.6 |
| Share options | ||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
| Anti-dilutive awards excluded from the calculation of diluted weighted-average shares outstanding (in shares) | 1.0 | 1.2 |
| RSE and PRSE awards | ||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
| Anti-dilutive awards excluded from the calculation of diluted weighted-average shares outstanding (in shares) | 0.6 | 0.5 |