v3.25.2
Litigation, Claims and Contingencies - Additional Information (Details)
$ in Millions
 9 Months Ended 12 Months Ended
Jun. 30, 2025
USD ($)
ServiceStationProperty
Facility
Site
Jun. 30, 2024
USD ($)
Sep. 30, 2024
USD ($)
Sep. 30, 2023
USD ($)
Sep. 30, 2022
USD ($)
Sep. 30, 2021
USD ($)
Asbestos litigation cost projection [Abstract]            
Number of Years Included in Asbestos Assumption 40 years          
Environmental Remediation Costs Recognized [Abstract]            
Number of sites were company is identified as a potentially responsible party under the superfund or similar state law | Site 53          
Number of current and former operating facilities subject to various environmental laws | Facility 107          
Total number of service station properties subject to various environmental laws | ServiceStationProperty 1,225          
Number of service stations being actively remediated | ServiceStationProperty 14          
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration] Other liabilities          
Accrual for environmental loss contingencies $ 242 $ 231 $ 221 $ 214    
Accrued environmental loss contingencies, noncurrent 185   164      
Recorded third-party environmental recoveries receivables 14   13      
Recorded third-party environmental recoveries, noncurrent 13   11      
Environmental exit costs, reasonably possible additional loss $ 510          
Maximum reserve for remediation reserve related to any one site (in hundredths) 20.00%          
Ashland [Member]            
Asbestos reserve [Roll Forward]            
Increase (decrease) in asbestos related reserve $ 16 24 24 9 $ 16  
Movement in Loss Contingency Receivable, Increase (Decrease) [Roll Forward]            
Insurance receivable 96 [1],[2] 100 [1],[2] 97 [1],[2] 95 [1],[2] 101 [1],[2] $ 100
Receivable adjustment 5          
Asbestos litigation cost projection [Abstract]            
Possible total future litigation defense and claim settlement costs 382          
Total reserves for asbestos claims 265 [3] 282 [3] 274 [3] 281 [3] 305 [3] 320
Hercules [Member]            
Asbestos reserve [Roll Forward]            
Increase (decrease) in asbestos related reserve 10 14 14 (2) 15  
Movement in Loss Contingency Receivable, Increase (Decrease) [Roll Forward]            
Insurance receivable 49 [4],[5] 51 [4],[5] 50 [4],[5] 47 [4],[5] 52 [4],[5] 47
Receivable adjustment 4          
Asbestos litigation cost projection [Abstract]            
Possible total future litigation defense and claim settlement costs 262          
Total reserves for asbestos claims $ 185 [6] $ 190 [6] $ 185 [6] $ 191 [6] $ 213 [6] $ 217
[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 $29 million and $28 million classified in accrued expenses and other liabilities on the Condensed Consolidated Balance Sheets as of June 30, 2025 and September 30, 2024, respectively.
[4] Includes $6 million classified in accounts receivable, net on the Condensed Consolidated Balance Sheets at both June 30, 2025 and September 30, 2024.
[5] The total allowance for credit losses was $1 million at June 30, 2025 and September 30, 2024.
[6] Includes $17 million classified in accrued expenses and other liabilities on the Condensed Consolidated Balance Sheets at both June 30, 2025 and September 30, 2024.