Retirement Plans - Pre-Tax in AOCI for Defined Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 25, 2015
U.S. Plans
Change in net loss:
Unrecognized net loss at beginning of fiscal year	$ 436	$ 325
Current year change recorded in accumulated other comprehensive income (loss)	32	136
Amortization reclassified to earnings	(40)	(25)
Unrecognized net loss at end of fiscal year	428	436
Estimated amortization of actuarial losses from accumulated other comprehensive income into net periodic pension benefit cost in next fiscal year
Amortization of net actuarial loss	40
Non-U.S. Plans
Change in net loss:
Unrecognized net loss at beginning of fiscal year	711	748
Current year change recorded in accumulated other comprehensive income (loss)	164	18
Amortization reclassified to earnings	(36)	(55)
Unrecognized net loss at end of fiscal year	839	711
Change in prior service credit:
Unrecognized prior service credit at beginning of fiscal year	(66)	(67)
Current year change recorded in accumulated other comprehensive income (loss)	(10)	(4)
Amortization reclassified to earnings	6	5
Unrecognized prior service credit at end of fiscal year	(70)	$ (66)
Estimated amortization of actuarial losses from accumulated other comprehensive income into net periodic pension benefit cost in next fiscal year
Amortization of net actuarial loss	43
Amortization of prior service credit	$ 7