Borrowings Commercial Paper Activity (Details) - USD ($) $ in Millions		12 Months Ended
		Sep. 28, 2019	Sep. 29, 2018
Commercial Paper Rollforward [Line Items]
Beginning Balance		$ 1,005	$ 2,772
Additions		8,770	8,079
Payments		(4,452)	(9,847)
Other Activity		19	1
Ending Balance		5,342	1,005
Commercial Paper with original maturities less that three months
Commercial Paper Rollforward [Line Items]
Beginning Balance	[1]	50	1,151
Additions	[1]	1,881	0
Payments	[1]	0	(1,099)
Other Activity	[1]	3	(2)
Ending Balance	[1]	1,934	50
Commercial paper with original maturities greater than three months
Commercial Paper Rollforward [Line Items]
Beginning Balance		955	1,621
Additions		6,889	8,079
Payments		(4,452)	(8,748)
Other Activity		16	3
Ending Balance		$ 3,408	$ 955

[1] Borrowings and reductions of borrowings are reported net.