Changes in Balance of Accumulated Other Comprehensive Loss (Parenthetical) (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 25, 2016	Sep. 27, 2015	Sep. 25, 2016		Sep. 27, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total reclassified from AOCL, net of tax				$ 499		$ 637
Recognition of net actuarial losses	[1]			703		831
Amortization of net prior service cost (credits)	[1]			(182)		(194)
Postretirement Benefit Plan Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total reclassified from AOCL, net of tax		$ 175	$ 212	387		637
Recognition of net actuarial losses		234	277	703	[1]	831	[1]
Amortization of net prior service cost (credits)		$ (59)	$ (65)	$ (182)	[1]	$ (194)	[1]

[1] Reclassifications from AOCL, net of tax, related to our postretirement benefit plans were recorded as a component of net periodic benefit cost for each period presented (Note 7). These amounts include $175 million and $212 million for the quarters ended September 25, 2016 and September 27, 2015, which are composed of the recognition of net actuarial losses of $234 million and $277 million for the quarters ended September 25, 2016 and September 27, 2015 and the amortization of net prior service (credits) costs of $(59) million and $(65) million for the quarters ended September 25, 2016 and September 27, 2015.