Components of Net Periodic Benefit Cost (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 29, 2012	Dec. 31, 2011
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 86	$ 70
Interest cost	109	110
Expected return on plan assets	(151)	(128)
Amortization of prior year service costs	2	3
Recognized net actuarial loss	104	77
Net periodic benefit cost	150	132
Postretirement Medical Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	5
Interest cost	17	19
Expected return on plan assets	(8)	(6)
Amortization of prior year service costs	(1)	(1)
Recognized net actuarial loss	10	8
Net periodic benefit cost	$ 22	$ 25