Net Periodic Benefit Cost (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 29, 2014	Mar. 30, 2013	Mar. 29, 2014	Mar. 30, 2013
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service costs	$ 71	$ 86	$ 142	$ 172
Interest costs	122	108	244	217
Expected return on plan assets	(162)	(150)	(323)	(301)
Amortization of prior-year service costs	3	3	7	5
Recognized net actuarial loss/(gain)	37	104	73	208
Net periodic benefit cost	71	151	143	301
Postretirement Medical Plans
Defined Benefit Plan Disclosure [Line Items]
Service costs	2	5	5	9
Interest costs	17	16	33	33
Expected return on plan assets	(9)	(7)	(18)	(15)
Amortization of prior-year service costs	(1)	0	(1)	(1)
Recognized net actuarial loss/(gain)	(2)	10	(4)	20
Net periodic benefit cost	$ 7	$ 24	$ 15	$ 46