v3.26.1
Litigation, Claims and Contingencies - Summary of Components of Environmental Remediation Expense Included within Selling, General and Administrative Expense (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Loss Contingencies [Line Items]        
Environmental expense $ 21 $ 46 $ 32 $ 49
Accretion 1 1 1 1
Legal expense 1 0 2 1
Total expense $ 23 $ 47 $ 35 $ 51
Environmental Remediation Expense, before Recovery, Statement of Income or Comprehensive Income [Extensible Enumeration] Selling, General and Administrative Expense Selling, General and Administrative Expense Selling, General and Administrative Expense Selling, General and Administrative Expense
Insurance receivable $ (2) $ (3) $ (3) $ (4)
Total expense, net of receivable activity $ 21 $ 44 $ 32 $ 47