Changes in Accumulated Other Comprehensive Loss, Net of Tax (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 27, 2014	Dec. 28, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance	$ (1,968)	$ (1,187)
Unrealized gains (losses) arising during the period	85	65
Reclassifications of net (gains) losses to net income	3	(22)
AOCI, Ending Balance	(1,880)	(1,144)
Estimated tax rate	37.00%	37.00%
Investments, net
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance	100	95
Unrealized gains (losses) arising during the period	(16)	18
Reclassifications of net (gains) losses to net income	0	(37)
AOCI, Ending Balance	84	76
Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance	204	83
Unrealized gains (losses) arising during the period	176	41
Reclassifications of net (gains) losses to net income	(41)	(10)
AOCI, Ending Balance	339	114
Unrecognized Pension and Postretirement Medical Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance	(2,196)	(1,271)
Unrealized gains (losses) arising during the period	0	0
Reclassifications of net (gains) losses to net income	44	25
AOCI, Ending Balance	(2,152)	(1,246)
Foreign Currency Translation and Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI, Beginning Balance	(76)	(94)
Unrealized gains (losses) arising during the period	(75)	6
Reclassifications of net (gains) losses to net income	0	0
AOCI, Ending Balance	$ (151)	$ (88)