Consolidated Financial Statement Details - Other Income/(Expense), Net (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Sep. 24, 2016	Sep. 26, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interest and dividend income	$ 5,201	$ 3,999	$ 2,921
Interest expense	(2,323)	(1,456)	(733)
Other expense, net	(133)	(1,195)	(903)
Total other income/(expense), net	$ 2,745	$ 1,348	$ 1,285