Components of Net Periodic Benefit Cost (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 30, 2013	Mar. 31, 2012	Mar. 30, 2013	Mar. 31, 2012
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 86	$ 69	$ 172	$ 139
Interest cost	108	109	217	219
Expected return on plan assets	(150)	(129)	(301)	(257)
Amortization of prior year service costs	3	4	5	7
Recognized net actuarial loss	104	78	208	155
Net periodic benefit cost	151	131	301	263
Postretirement Medical Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	6	9	11
Interest cost	16	18	33	37
Expected return on plan assets	(7)	(6)	(15)	(12)
Amortization of prior year service costs	0	0	(1)	(1)
Recognized net actuarial loss	10	8	20	16
Net periodic benefit cost	$ 24	$ 26	$ 46	$ 51