Changes in Balance of Accumulated Other Comprehensive Loss (Parenthetical) (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 26, 2016	Jun. 28, 2015	Jun. 26, 2016		Jun. 28, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total reclassified from AOCL, net of tax				$ 340		$ 425
Recognition of net actuarial losses	[1]			469		554
Amortization of net prior service cost (credits)	[1]			(123)		(129)
Postretirement Benefit Plan Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total reclassified from AOCL, net of tax		$ 173	$ 213	346		425
Recognition of net actuarial losses		235	277	469	[1]	554	[1]
Amortization of net prior service cost (credits)		$ (62)	$ (64)	$ (123)	[1]	$ (129)	[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 $173 million and $213 million for the quarters ended June 26, 2016 and June 28, 2015, which are comprised of the recognition of net actuarial losses of $235 million and $277 million for the quarters ended June 26, 2016 and June 28, 2015 and the amortization of net prior service (credits) costs of $(62) million and $(64) million for the quarters ended June 26, 2016 and June 28, 2015.