Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 27, 2014	Jun. 28, 2013	Jun. 27, 2014	Jun. 28, 2013
Pension Plans [Member]
Components of net periodic benefit cost:
Service cost	$ 27	$ 33	$ 54	$ 65
Interest cost	37	33	73	66
Expected return on plan assets	(49)	(41)	(97)	(83)
Amortization of prior service costs (credits)			1
Amortization of net loss (gain)	5	21	9	43
Curtailment loss			1
Net periodic benefit cost	20	46	41	91
Postretirement Benefit Plans [Member]
Components of net periodic benefit cost:
Service cost	1	1	2	2
Interest cost	2	1	4	3
Expected return on plan assets	(1)	(1)	(2)	(2)
Amortization of prior service costs (credits)			(1)	1
Amortization of net loss (gain)	(1)		(1)	(1)
Curtailment loss
Net periodic benefit cost	$ 1	$ 1	$ 2	$ 3