Leases, Codification Topic 842 (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Lessee, Lease, Description [Line Items]
Operating Lease, Weighted Average Remaining Lease Term	6 years 10 months 24 days
Operating Lease, Weighted Average Discount Rate, Percent	2.20%
Operating Lease, Cost	$ 132	$ 131
Rental expense for operating leases			$ 169
Gross Proceeds from Sale Leaseback Transaction	225
Other Operating Income (Expense)
Lessee, Lease, Description [Line Items]
Sale and Leaseback Transaction, Gain (Loss), Net	$ 158
Minimum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	1 year
Lessee, Operating Lease, Renewal Term	6 months
Minimum | Sale Leaseback Transaction, Term of Contract
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	2 years
Maximum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	25 years
Lessee, Operating Lease, Renewal Term	12 months
Maximum | Sale Leaseback Transaction, Term of Contract
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	3 years