Pension and Other Benefit Programs - Key Assumptions (Detail)	12 Months Ended
	Oct. 03, 2015	Sep. 27, 2014	Sep. 28, 2013
Pension Plans
Schedule of Net Periodic Benefit Costs Weighted Average Assumptions [Line Items]
Discount rate	4.47%	4.40%	5.00%
Rate of return on plan assets	7.50%	7.50%	7.50%
Rate of salary increase	4.00%	4.00%	4.00%
Postretirement Medical Plans
Schedule of Net Periodic Benefit Costs Weighted Average Assumptions [Line Items]
Discount rate	4.47%	4.40%	5.00%
Rate of return on plan assets	7.50%	7.50%	7.50%
Year 1 increase in cost of benefits	7.00%	7.00%	7.25%
Rate of increase to which the cost of benefits is assumed to decline (the ultimate trend rate)	4.25%	4.25%	4.25%
Year that the rate reaches the ultimate trend rate	2029	2028	2027