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		6 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Numerator:
Net income	$ 11,249	$ 11,561	$ 33,485	$ 31,526
Denominator:
Weighted-average basic shares outstanding (in shares)	4,360,101	4,674,071	4,387,570	4,704,945
Effect of dilutive securities (in shares)	44,590	26,575	42,078	32,004
Weighted-average diluted shares (in shares)	4,404,691	4,700,646	4,429,648	4,736,949
Basic earnings per share (in dollars per share)	$ 2.58	$ 2.47	$ 7.63	$ 6.70
Diluted earnings per share (in dollars per share)	$ 2.55	$ 2.46	$ 7.56	$ 6.66