Derivative and Financial Instruments (Notional Amounts of Outstanding Derivative Contracts) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018
Interest Rate Contract [Member]
Derivative [Line Items]
Notional amounts of outstanding derivative contracts	$ 1,250	$ 750
Cross-Currency Swap [Member]
Derivative [Line Items]
Notional amounts of outstanding derivative contracts	373	434
Foreign Currency Contract - Other [Member]
Derivative [Line Items]
Notional amounts of outstanding derivative contracts	1,157	914
Dairy Contracts [Member]
Derivative [Line Items]
Notional amounts of outstanding derivative contracts	7	16
Diesel and Other Contracts [Member]
Derivative [Line Items]
Notional amounts of outstanding derivative contracts	$ 35	$ 21