Net Periodic Benefit Cost (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 29, 2012	Oct. 01, 2011	Oct. 02, 2010
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service costs	$ 278	$ 293	$ 263
Interest costs	440	411	396
Expected return on plan assets	(514)	(440)	(415)
Amortization of prior year service costs	12	14	14
Recognized net actuarial (gain)/loss	309	230	154
Net periodic benefit cost	525	508	412
Postretirement Medical Plans
Defined Benefit Plan Disclosure [Line Items]
Service costs	21	18	21
Interest costs	74	66	70
Expected return on plan assets	(23)	(24)	(26)
Amortization of prior year service costs	(2)	(1)	(2)
Recognized net actuarial (gain)/loss	31	9	7
Net periodic benefit cost	$ 101	$ 68	$ 70