Fair Value Measurements Activity Between Levels of the Fair Value Hierarchy, Assets (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Jun. 29, 2014	Jun. 30, 2013
Auction Rate Securities [Member]
Activity for Marketable Securities Classified Within Level 3 of the Valuation Hierarchy [Roll Forward]
Beginning balance of Level 3	$ 83	$ 118
Total realized and unrealized gains or losses included in investment income, net	0	0
Total realized and unrealized gains or losses included in other comprehensive income	0	1
Purchases	0	0
Sales	0	0
Settlements	0	(36)
Transfers (out of) into Level 3	0	0
Ending balance of Level 3	83	83
Mortgage- and asset-backed securities
Activity for Marketable Securities Classified Within Level 3 of the Valuation Hierarchy [Roll Forward]
Beginning balance of Level 3	239	203
Total realized and unrealized gains or losses included in investment income, net	10	4
Total realized and unrealized gains or losses included in other comprehensive income	(4)	(2)
Purchases	86	157
Sales	(124)	(10)
Settlements	(28)	(66)
Transfers (out of) into Level 3	(2)	18
Ending balance of Level 3	$ 177	$ 304