Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 24, 2016	Jun. 26, 2015	Jun. 24, 2016	Jun. 26, 2015
Pension Plans [Member]
Components of net periodic benefit cost:
Service cost	$ 28	$ 32	$ 55	$ 64
Interest cost	34	37	69	74
Expected return on plan assets	(51)	(52)	(102)	(104)
Amortization of prior service costs (credits)				1
Amortization of net loss	13	17	26	34
Net periodic benefit cost	24	34	48	69
Postretirement Benefit Plans [Member]
Components of net periodic benefit cost:
Service cost		1	1	2
Interest cost	2	2	3	4
Expected return on plan assets	(1)	(1)	(2)	(2)
Amortization of prior service costs (credits)		(1)	(1)	(2)
Amortization of net loss
Net periodic benefit cost	$ 1	$ 1	$ 1	$ 2