v3.26.1
Fair Value Measurements - Assets and Liabilities Measured at Fair Value (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Sep. 30, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets $ 120 $ 15
Deferred compensation plan assets 70 63
Total assets 492 368
Derivative liabilities 74 24
Contingent earn-out liabilities   19
Total liabilities 74 43
Quoted Prices in Active Markets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets 0 0
Deferred compensation plan assets 70 63
Total assets 372 353
Derivative liabilities 0 0
Contingent earn-out liabilities   0
Total liabilities 0 0
Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets 120 15
Deferred compensation plan assets 0 0
Total assets 120 15
Derivative liabilities 74 24
Contingent earn-out liabilities   0
Total liabilities 74 24
Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets 0 0
Deferred compensation plan assets 0 0
Total assets 0 0
Derivative liabilities 0 0
Contingent earn-out liabilities   19
Total liabilities 0 19
Fixed Income Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Exchange traded funds 71 73
Fixed Income Securities | Quoted Prices in Active Markets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Exchange traded funds 71 73
Fixed Income Securities | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Exchange traded funds 0 0
Fixed Income Securities | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Exchange traded funds 0 0
Equity Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Exchange traded funds 231 217
Equity Securities | Quoted Prices in Active Markets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Exchange traded funds 231 217
Equity Securities | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Exchange traded funds 0 0
Equity Securities | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Exchange traded funds $ 0 $ 0