Changes in Balance of Accumulated Other Comprehensive Loss, Net of Income Taxes (Parenthetical) (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 25, 2017	Jun. 26, 2016	Jun. 25, 2017		Jun. 26, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total reclassified from AOCL				$ 409		$ 347
Recognition of net actuarial losses	[1]			516		469
Amortization of net prior service credits	[1]			(114)		(123)
Postretirement Benefit Plan Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total reclassified from AOCL		$ 200	$ 173	402		346
Recognition of net actuarial losses		258	235	516	[1]	469	[1]
Amortization of net prior service credits		$ (58)	$ (62)	$ (114)	[1]	$ (123)	[1]

[1] Reclassifications from AOCL related to our postretirement benefit plans were recorded as a component of net periodic benefit cost for each period presented (see "Note 6 - Postretirement Plans"). These amounts include $200 million and $173 million, net of tax, for the quarters ended June 25, 2017 and June 26, 2016, which are comprised of the recognition of net actuarial losses of $258 million and $235 million for the quarters ended June 25, 2017 and June 26, 2016 and the amortization of net prior service credits of $(58) million and $(62) million for the quarters ended June 25, 2017 and June 26, 2016.