v3.25.2
Litigation, Claims and Contingencies - Summary of Progression of Insurance Receivable (Details) - USD ($)
$ in Millions
 9 Months Ended 12 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2022
Ashland [Member]          
Movement in Loss Contingency Receivable, Increase (Decrease) [Roll Forward]          
Insurance receivable - beginning of year $ 97 [1],[2] $ 95 [1],[2] $ 95 [1],[2] $ 101 [1],[2] $ 100
Receivable adjustment 5 11 11 3 7
Amounts collected (6) (6) (9) (9) (6)
Insurance receivable - end of period [1],[2] 96 100 97 95 101
Hercules [Member]          
Movement in Loss Contingency Receivable, Increase (Decrease) [Roll Forward]          
Insurance receivable - beginning of year 50 [3],[4] 47 [3],[4] 47 [3],[4] 52 [3],[4] 47
Receivable adjustment 4 6 6 (3) 7
Amounts collected (5) (2) (3) (2) (2)
Insurance receivable - end of period [3],[4] $ 49 $ 51 $ 50 $ 47 $ 52
[1] Includes $10 million and $9 million classified in accounts receivable, net on the Condensed Consolidated Balance Sheets at June 30, 2025 and September 30, 2024, respectively.
[2] The total allowance for credit losses was $1 million at June 30, 2025 and September 30, 2024.
[3] Includes $6 million classified in accounts receivable, net on the Condensed Consolidated Balance Sheets at both June 30, 2025 and September 30, 2024.
[4] The total allowance for credit losses was $1 million at June 30, 2025 and September 30, 2024.