Changes in Balance of Accumulated Other Comprehensive Loss (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 25, 2012
Schedule of Postretirement Benefit Plans and Other Adjustments Recognized in Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (13,493)		$ (11,257)
Other comprehensive income before reclassifications	(40)		23
Net actuarial losses	244	[1]	193	[1]
Prior service cost	10	[1]	10	[1]
Other	(3)		1
Total reclassified from AOCL	251		204
Other comprehensive income, net of tax	211		227
Ending balance	(13,282)		(11,030)
Postretirement Benefit Plan Adjustments
Schedule of Postretirement Benefit Plans and Other Adjustments Recognized in Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(13,532)		(11,186)
Net actuarial losses	244	[1]	193	[1]
Prior service cost	10	[1]	10	[1]
Total reclassified from AOCL	254		203
Other comprehensive income, net of tax	254		203
Ending balance	(13,278)		(10,983)
Other, net
Schedule of Postretirement Benefit Plans and Other Adjustments Recognized in Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	39		(71)
Other comprehensive income before reclassifications	(40)		23
Other	(3)		1
Total reclassified from AOCL	(3)		1
Other comprehensive income, net of tax	(43)		24
Ending balance	$ (4)		$ (47)

[1] Amounts related to our postretirement benefit plans that were reclassified from AOCL were recorded as a component of net periodic benefit cost for each period presented (Note 5).