Changes in Balance of Accumulated Other Comprehensive Loss (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]
Beginning balance				$ (11,444)		$ (11,870)
Other comprehensive loss before reclassifications				(7)		(11)
Amounts reclassified from AOCL
Recognition of net actuarial losses	[1]			469		554
Amortization of net prior service credits	[1]			(123)		(129)
Other				1
Total reclassified from AOCL				340		425
Other comprehensive income (loss), net of tax		$ 150	$ 259	340		414
Ending balance		(11,104)	(11,456)	(11,104)		(11,456)
Postretirement Benefit Plan Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance				(11,314)		(11,813)
Amounts reclassified from AOCL
Recognition of net actuarial losses		235	277	469	[1]	554	[1]
Amortization of net prior service credits		(62)	(64)	(123)	[1]	(129)	[1]
Total reclassified from AOCL		173	213	346		425
Other comprehensive income (loss), net of tax				346		425
Ending balance		(10,968)	(11,388)	(10,968)		(11,388)
Other, net
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance				(130)		(57)
Other comprehensive loss before reclassifications				(7)		(11)
Amounts reclassified from AOCL
Other				1
Total reclassified from AOCL				(6)
Other comprehensive income (loss), net of tax				(6)		(11)
Ending balance		$ (136)	$ (68)	$ (136)		$ (68)

[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.