Leases - Right of Use Assets and Operating Lease Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2023	Sep. 30, 2022
Leases [Abstract]
Right-of-use assets (Other assets)	$ 550	$ 439
Right-of-Use Asset (other assets) [Extensible Enumeration]	Assets, Noncurrent, Other than Noncurrent Investments and Property, Plant and Equipment	Assets, Noncurrent, Other than Noncurrent Investments and Property, Plant and Equipment
Current lease liabilities (Accrued expenses)	$ 144	$ 128
Current lease liabilities (accrued expenses)[Extensible Enumeration]	Accrued expenses	Accrued expenses
Noncurrent lease liabilities (Other liabilities)	$ 404	$ 312
Noncurrent lease liabilities (other liabilities) [Extensible Enumeration]	Other	Other