Accumulated Other Comprehensive Loss, Before Tax, not yet Recognized in Net Periodic Benefit Cost (Detail) (USD $) In Millions, unless otherwise specified	Sep. 29, 2012	Oct. 01, 2011
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service (cost) / credit	$ (23)
Unrecognized net actuarial loss	(5,089)
Total amounts included in accumulated other comprehensive loss	(5,112)
Prepaid / (accrued) pension cost	271
Net balance sheet liability	(4,841)
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service (cost) / credit	(28)
Unrecognized net actuarial loss	(4,631)
Total amounts included in accumulated other comprehensive loss	(4,659)
Prepaid / (accrued) pension cost	1,178
Net balance sheet liability	(3,481)	(2,930)
Postretirement Medical Plans
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service (cost) / credit	5
Unrecognized net actuarial loss	(458)
Total amounts included in accumulated other comprehensive loss	(453)
Prepaid / (accrued) pension cost	(907)
Net balance sheet liability	$ (1,360)	$ (1,276)