Leases - Additional Information (Details) $ in Millions	12 Months Ended
	Sep. 30, 2022 USD ($) renewalOption	Sep. 30, 2021 USD ($) renewalOption
Lessee, Lease, Description [Line Items]
Number of renewal options (or more) | renewalOption	1	1
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
ROU assets	$ 480	$ 515
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued liabilities	Accrued liabilities
Current portion of lease liabilities	$ 98	$ 103
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other liabilities	Other liabilities
Noncurrent portion of lease liabilities	$ 422	$ 471
Operating lease cost	$ 117	$ 111
Weighted average remaining lease term (in years)	6 years	6 years
Weighted average discount rate	2.15%	2.23%
Right-of-use asset obtained in exchange for operating lease liability	$ 74	$ 96
Operating leases, not yet commenced, lease obligations	$ 531
Minimum
Lessee, Lease, Description [Line Items]
Operating leases, non-cancellable lease terms	1 year
Maximum
Lessee, Lease, Description [Line Items]
Operating leases, non-cancellable lease terms	15 years