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								12 Months Ended
	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Dec. 31, 2016	Sep. 24, 2016	Jun. 25, 2016	Mar. 26, 2016	Dec. 26, 2015	Sep. 30, 2017	Sep. 24, 2016	Sep. 26, 2015
Numerator:
Net income	$ 10,714	$ 8,717	$ 11,029	$ 17,891	$ 9,014	$ 7,796	$ 10,516	$ 18,361	$ 48,351	$ 45,687	$ 53,394
Denominator:
Weighted-average shares outstanding (in shares)									5,217,242	5,470,820	5,753,421
Effect of dilutive securities (in shares)									34,450	29,461	39,648
Weighted-average diluted shares (in shares)									5,251,692	5,500,281	5,793,069
Basic earnings per share (in dollars per share)	$ 2.08	$ 1.68	$ 2.11	$ 3.38	$ 1.68	$ 1.43	$ 1.91	$ 3.30	$ 9.27	$ 8.35	$ 9.28
Diluted earnings per share (in dollars per share)	$ 2.07	$ 1.67	$ 2.10	$ 3.36	$ 1.67	$ 1.42	$ 1.90	$ 3.28	$ 9.21	$ 8.31	$ 9.22