Debt - Fiscal 2025 Transactions (Narrative) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2025	Jun. 29, 2025	Feb. 05, 2025	Sep. 30, 2024	Sep. 30, 2023
Debt Instrument [Line Items]
Weighted-average interest rate of total debt	4.10%			4.30%	4.10%
Beethoven JV Credit Agreement | Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, accordion feature, increase limit		$ 700,000,000
Drawdowns on credit facility	$ 0
Tempo | Tempo Asset-Based Notes due 2050
Debt Instrument [Line Items]
Total debt, including the current portion	311,000,000			$ 0
Weighted-average interest rate of total debt			4.62%
Acquisition Corp.
Debt Instrument [Line Items]
Total debt, including the current portion	4,090,000,000			4,048,000,000
Acquisition Corp. | Revolving Credit Facility
Debt Instrument [Line Items]
Total debt, including the current portion	0			0
Acquisition Corp. | Beethoven JV Credit Agreement | Revolving Credit Facility
Debt Instrument [Line Items]
Total debt, including the current portion	0			$ 0
Line of credit facility, maximum borrowing capacity	$ 500,000,000