Fair Value Measurements Activity Between Levels of the Fair Value Hierarchy, Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 24, 2017	Sep. 25, 2016
Marketable Securities [Member]
Activity for Marketable Securities Classified Within Level 3 of the Valuation Hierarchy [Roll Forward]
Beginning balance of Level 3	$ 43	$ 224
Total realized and unrealized gains or losses included in other comprehensive income (loss)	0	(1)
Issuances	0	0
Purchases	0	2
Sales	0	(106)
Settlements	(3)	(45)
Transfers into of Level 3	0	0
Transfers out of Level 3	0	(27)
Ending balance of Level 3	40	43
Other Investments [Member]
Activity for Marketable Securities Classified Within Level 3 of the Valuation Hierarchy [Roll Forward]
Beginning balance of Level 3	37	13
Total realized and unrealized gains or losses included in other comprehensive income (loss)	8	15
Issuances	0	0
Purchases	111	40
Sales	0	0
Settlements	(34)	(8)
Transfers into of Level 3	0	0
Transfers out of Level 3	0	0
Ending balance of Level 3	125	37
Other Liabilities [Member]
Activity for Marketable Securities Classified Within Level 3 of the Valuation Hierarchy [Roll Forward]
Beginning balance of Level 3	0
Total realized and unrealized gains or losses included in other comprehensive income (loss)	0
Issuances	203
Purchases	0
Sales	0
Settlements	0
Transfers into of Level 3	0
Transfers out of Level 3	0
Ending balance of Level 3	196	0
Selling, general and administrative [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 [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 [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	(7)
Investment Income [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	(4)
Investment Income [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	3	$ (23)
Investment Income [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