v3.26.1
Financial Information by Segment - Revenues From External Customers That are Categorized as Unallocated and Other (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting Information [Line Items]        
Revenues from external customers $ 982 $ 923 $ 2,735 $ 2,814
Unallocated and Other [Member]        
Segment Reporting Information [Line Items]        
Revenues from external customers 32 30 93 94
Unallocated and Other [Member] | Shipping and Handling Fees [Member]        
Segment Reporting Information [Line Items]        
Revenues from external customers 34 28 91 85
Unallocated and Other [Member] | Other [Member]        
Segment Reporting Information [Line Items]        
Revenues from external customers $ (2) $ 2 $ 2 $ 9