v3.25.2
Fair Value Measurements - Fair Value of Long-Term Debt (Details) - USD ($)
$ in Billions
Jun. 30, 2025
Sep. 30, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair value of long term debt $ 8.6 $ 8.3
Public debt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair value of long term debt 8.3 8.1
Other long-term debt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair value of long term debt $ 0.3 $ 0.2