Shareholders' Equity (Details) - USD ($) $ / shares in Units, shares in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2024 |
Jun. 30, 2023 |
Jun. 30, 2024 |
Jun. 30, 2023 |
|
| Equity, Class of Treasury Stock [Line Items] | ||||
| Purchased call option strike price for share repurchase contracts | 0 | 0 | ||
| Written Call Option Strike Price for share repurchase contracts | 99.45 | 99.45 | ||
| Payment for share repurchase contracts | $ (50,000,000.0) | $ 0 | ||
| Share repurchase contracts - number of shares received | 0.5 | 0.5 | ||
| Proceeds from share repurchase contracts | $ 50,900,000 | $ 0 | ||
| Common Stock | ||||
| Equity, Class of Treasury Stock [Line Items] | ||||
| Shares repurchased | 2.0 | 1.9 | 2.5 | 2.9 |
| Average price per share (a) | $ 104.18 | $ 86.64 | $ 100.71 | $ 86.91 |
| Total Share Repurchase Cost | $ 209,700,000 | $ 166,800,000 | $ 254,500,000 | $ 250,500,000 |
| Sales and Excise Tax Payable, Current | $ 1,800,000 | 1,800,000 | ||
| Accrued repurchases of common stock | $ 4,000,000.0 | $ 8,100,000 | ||