Summary of Significant Accounting Policies - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Numerator:
Net income	$ 10,044	$ 11,519	$ 41,570	$ 45,406
Denominator:
Weighted-average basic shares outstanding (in shares)	4,570,633	4,882,167	4,660,175	5,006,640
Effect of dilutive securities (in shares)	30,747	44,442	31,584	44,323
Weighted-average diluted shares (in shares)	4,601,380	4,926,609	4,691,759	5,050,963
Basic earnings per share (in dollars per share)	$ 2.20	$ 2.36	$ 8.92	$ 9.07
Diluted earnings per share (in dollars per share)	$ 2.18	$ 2.34	$ 8.86	$ 8.99