Commitments and Contingencies - Narrative (Details) $ in Millions |
12 Months Ended | |
|---|---|---|
|
Sep. 30, 2026
USD ($)
site
|
Sep. 30, 2025
USD ($)
|
|
| Commitments and Contingencies Disclosure [Abstract] | ||
| Number of Superfund sites designated potentially responsible party at | site | 14 | |
| Accrual for environmental loss contingencies, net of related receivables | $ 45 | $ 49 |
| Asset retirement obligation, net of recoveries | $ 48 | $ 51 |