Financial Instruments (Carrying Amount and Cumulative Hedging Adjustment) (Details) - USD ($) $ in Millions |
Dec. 31, 2024 |
Sep. 30, 2024 |
|---|---|---|
| Current portion of long-term debt | ||
| Derivative Instruments and Hedging Activities Disclosures [Line Items] | ||
| Carrying amounts of hedged item | $ 544.4 | $ 0.0 |
| Cumulative hedging adjustment, included in carrying amount | (5.2) | 0.0 |
| Long-term debt | ||
| Derivative Instruments and Hedging Activities Disclosures [Line Items] | ||
| Carrying amounts of hedged item | 1,502.3 | 2,057.1 |
| Cumulative hedging adjustment, included in carrying amount | $ (42.3) | $ (36.6) |