Income Taxes - Reconciliation of the Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 24, 2016
Income Tax Disclosure [Abstract]
Computed expected tax	$ 17,890	$ 22,431	$ 21,480
State taxes, net of federal effect	271	185	553
Impacts of the Act	1,515	0	0
Earnings of foreign subsidiaries	(5,606)	(6,135)	(5,582)
Domestic production activities deduction	(195)	(209)	(382)
Research and development credit, net	(560)	(678)	(371)
Other	57	144	(13)
Provision for income taxes	$ 13,372	$ 15,738	$ 15,685
Effective tax rate	18.30%	24.60%	25.60%