Consolidated Financial Statement Details - Property, Plant and Equipment, Net (Details) - USD ($) $ in Millions	Sep. 29, 2018	Sep. 30, 2017
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 90,403	$ 75,076
Accumulated depreciation and amortization	(49,099)	(41,293)
Total property, plant and equipment, net	41,304	33,783
Land and buildings
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	16,216	13,587
Machinery, equipment and internal-use software
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	65,982	54,210
Leasehold improvements
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 8,205	$ 7,279