Fair Value Measurements - Narrative (Details) - USD ($) $ in Billions	Sep. 30, 2022	Sep. 30, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	$ 7.3	$ 8.5
Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	7.1	8.3
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, fair value disclosure	$ 0.2	$ 0.2