Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 23, 2016	Sep. 25, 2015	Sep. 23, 2016	Sep. 25, 2015
Pension Plans [Member]
Components of net periodic benefit cost:
Service cost	$ 25	$ 29	$ 80	$ 93
Interest cost	32	38	101	112
Expected return on plan assets	(47)	(51)	(149)	(155)
Amortization of prior service costs (credits)				1
Amortization of net loss (gains)	13	17	39	51
Curtailment loss		3		3
Net periodic benefit cost	23	36	71	105
Postretirement Benefit Plans [Member]
Components of net periodic benefit cost:
Service cost			1	2
Interest cost	1	1	4	5
Expected return on plan assets	(1)	(1)	(3)	(3)
Amortization of prior service costs (credits)			(1)	(2)
Amortization of net loss (gains)	(1)		(1)
Curtailment loss
Net periodic benefit cost	$ (1)			$ 2