Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 29, 2018	Sep. 30, 2017
Deferred tax assets:
Accrued liabilities and other reserves	$ 3,151	$ 4,019
Basis of capital assets	137	1,230
Deferred revenue	1,141	1,521
Deferred cost sharing	0	667
Share-based compensation	513	703
Unrealized losses	871	0
Other	797	834
Total deferred tax assets	6,610	8,974
Deferred tax liabilities:
Earnings of foreign subsidiaries	275	36,355
Other	501	207
Total deferred tax liabilities	776	36,562
Net deferred tax assets	$ 5,834
Net deferred tax liabilities		$ (27,588)