Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 25, 2015	Sep. 26, 2014	Sep. 25, 2015	Sep. 26, 2014
Pension Plans [Member]
Components of net periodic benefit cost:
Service cost	$ 29	$ 26	$ 93	$ 80
Interest cost	38	37	112	110
Expected return on plan assets	$ (51)	$ (48)	(155)	(145)
Amortization of prior service costs (credits)			1	1
Amortization of net loss (gain)	$ 17	$ 4	51	13
Curtailment loss	3		3	1
Net periodic benefit cost	$ 36	$ 19	105	$ 60
Postretirement Benefit Plans [Member]
Components of net periodic benefit cost:
Service cost		(2)	2
Interest cost	$ 1	4	5	$ 8
Expected return on plan assets	$ (1)	$ (1)	(3)	(3)
Amortization of prior service costs (credits)			$ (2)	(1)
Amortization of net loss (gain)		$ (1)		(2)
Curtailment loss		(1)		(1)
Net periodic benefit cost		$ (1)	$ 2	$ 1