Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 30, 2017
Federal:
Current	$ 6,384	$ 41,425	$ 7,842
Deferred	(2,939)	(33,819)	5,980
Federal income tax expense/(benefit)	3,445	7,606	13,822
State:
Current	475	551	259
Deferred	(67)	48	2
State income tax expense/(benefit)	408	599	261
Foreign:
Current	3,962	3,986	1,671
Deferred	2,666	1,181	(16)
Foreign income tax expense/(benefit)	6,628	5,167	1,655
Provision for income taxes	$ 10,481	$ 13,372	$ 15,738