v3.26.1
Derivative Instruments and Hedging Activities - Schedule of Effective Portion of Pretax Gains (Losses) (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Derivative Instruments, Gain (Loss) [Line Items]        
Total $ (4) $ 5 $ (6) $ (9)
Foreign currency exchange derivatives | Income Statement Location [Axis]: us-gaap:CostOfRevenue        
Derivative Instruments, Gain (Loss) [Line Items]        
Foreign currency exchange derivatives 1 2 (1) 2
Foreign currency exchange derivatives | Income Statement Location [Axis]: us-gaap:InterestIncomeExpenseNet        
Derivative Instruments, Gain (Loss) [Line Items]        
Foreign currency exchange derivatives (5) 3 (5) (11)
Foreign currency exchange derivatives | Cash Flow Hedging        
Derivative Instruments, Gain (Loss) [Line Items]        
Foreign currency exchange derivatives 28 31 43 30
Foreign currency exchange derivatives | Cash Flow Hedging | Income Statement Location [Axis]: us-gaap:CostOfRevenue        
Derivative Instruments, Gain (Loss) [Line Items]        
Foreign currency exchange derivatives $ 16 $ 1 $ 46 $ (16)