Short-Term Borrowings And Lines Of Credit (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015	Apr. 30, 2014
Short Term Borrowings And Lines Of Credit [Line Items]
Current maturities of long-term debt	$ 267	$ 291
Commercial paper	2,317	2,261
Total	$ 2,584	$ 2,552
Interest rate for weighted-average short-term borrowings at year end	0.50%	0.20%
Five-year revolving credit facility [Member]
Short Term Borrowings And Lines Of Credit [Line Items]
Line of credit facility, maximum borrowing capacity	$ 3,500
Line of credit facility, amount outstanding	$ 0	$ 0
Four-year revolving credit facility [Member]
Short Term Borrowings And Lines Of Credit [Line Items]
Line of credit facility, maximum borrowing capacity			$ 2,750