v3.26.1
Fair Value Measurements - Assets and Liabilities Measured at Fair Value (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Sep. 30, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total assets $ 454 $ 368
Total liabilities 150 43
Quoted Prices in Active Markets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total assets 339 353
Total liabilities 0 0
Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total assets 115 15
Total liabilities 136 24
Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total assets 0 0
Total liabilities 14 19
Other current assets    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets 115 15
Other current assets | Quoted Prices in Active Markets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets 0 0
Other current assets | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets 115 15
Other current assets | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets 0 0
Other noncurrent assets    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Deferred compensation plan assets 63 63
Other noncurrent assets | Quoted Prices in Active Markets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Deferred compensation plan assets 63 63
Other noncurrent assets | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Deferred compensation plan assets 0 0
Other noncurrent assets | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Deferred compensation plan assets 0 0
Other noncurrent assets | Fixed Income Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in marketable common stock 71 73
Other noncurrent assets | Fixed Income Securities | Quoted Prices in Active Markets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in marketable common stock 71 73
Other noncurrent assets | Fixed Income Securities | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in marketable common stock 0 0
Other noncurrent assets | Fixed Income Securities | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in marketable common stock 0 0
Other noncurrent assets | Equity Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in marketable common stock 205 217
Other noncurrent assets | Equity Securities | Quoted Prices in Active Markets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in marketable common stock 205 217
Other noncurrent assets | Equity Securities | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in marketable common stock 0 0
Other noncurrent assets | Equity Securities | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments in marketable common stock 0 0
Other current liabilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 136 24
Contingent earn-out liabilities 14 19
Other current liabilities | Quoted Prices in Active Markets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 0 0
Contingent earn-out liabilities 0 0
Other current liabilities | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 136 24
Contingent earn-out liabilities 0 0
Other current liabilities | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 0 0
Contingent earn-out liabilities $ 14 $ 19