Fair Value Measurements Activity Between Levels of the Fair Value Hierarchy, Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 24, 2017
Marketable Securities [Member]
Activity for Marketable Securities Classified Within Level 3 of the Valuation Hierarchy [Roll Forward]
Beginning balance of Level 3	$ 40	$ 43
Total realized and unrealized gains or losses included in other comprehensive (loss) income	0	0
Issuances	0	0
Purchases	0	0
Sales	0	0
Settlements	(5)	(3)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance of Level 3	35	40
Other Investments [Member]
Activity for Marketable Securities Classified Within Level 3 of the Valuation Hierarchy [Roll Forward]
Beginning balance of Level 3	125	37
Total realized and unrealized gains or losses included in other comprehensive (loss) income	7	8
Issuances	0	0
Purchases	7	111
Sales	0	0
Settlements	(129)	(34)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance of Level 3	16	125
Other Liabilities [Member]
Activity for Marketable Securities Classified Within Level 3 of the Valuation Hierarchy [Roll Forward]
Beginning balance of Level 3	196	0
Total realized and unrealized gains or losses included in other comprehensive (loss) income	0	0
Issuances	0	203
Purchases	0	0
Sales	0	0
Settlements	(46)	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance of Level 3	86	196
Selling, general and administrative and other expenses [Member] | Marketable Securities [Member]
Activity for Marketable Securities Classified Within Level 3 of the Valuation Hierarchy [Roll Forward]
Total realized and unrealized gains or losses included in earnings	0	0
Selling, general and administrative and other expenses [Member] | Other Investments [Member]
Activity for Marketable Securities Classified Within Level 3 of the Valuation Hierarchy [Roll Forward]
Total realized and unrealized gains or losses included in earnings	0	0
Selling, general and administrative and other expenses [Member] | Other Liabilities [Member]
Activity for Marketable Securities Classified Within Level 3 of the Valuation Hierarchy [Roll Forward]
Total realized and unrealized gains or losses included in earnings	(64)	(7)
Investment and other income, net [Member] | Marketable Securities [Member]
Activity for Marketable Securities Classified Within Level 3 of the Valuation Hierarchy [Roll Forward]
Total realized and unrealized gains or losses included in earnings	0	0
Investment and other income, net [Member] | Other Investments [Member]
Activity for Marketable Securities Classified Within Level 3 of the Valuation Hierarchy [Roll Forward]
Total realized and unrealized gains or losses included in earnings	6	3
Investment and other income, net [Member] | Other Liabilities [Member]
Activity for Marketable Securities Classified Within Level 3 of the Valuation Hierarchy [Roll Forward]
Total realized and unrealized gains or losses included in earnings	$ 0	$ 0