Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 27, 2015	Jun. 28, 2014	Jun. 27, 2015	Jun. 28, 2014
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service costs	$ 82	$ 71	$ 248	$ 213
Interest costs	129	121	391	365
Expected return on plan assets	(178)	(161)	(534)	(484)
Amortization of prior- year service costs	4	4	12	11
Recognized net actuarial loss/(gain)	62	37	185	110
Net periodic benefit cost	99	72	302	215
Postretirement Medical Plans
Defined Benefit Plan Disclosure [Line Items]
Service costs	4	3	11	8
Interest costs	17	16	51	49
Expected return on plan assets	(10)	(9)	(29)	(27)
Amortization of prior- year service costs	0	0	(1)	(1)
Recognized net actuarial loss/(gain)	3	(2)	8	(6)
Net periodic benefit cost	$ 14	$ 8	$ 40	$ 23