Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 26, 2014	Sep. 27, 2013	Sep. 26, 2014	Sep. 27, 2013
Pension Plans [Member]
Components of net periodic benefit cost:
Service cost	$ 26	$ 30	$ 80	$ 95
Interest cost	37	33	110	99
Expected return on plan assets	(48)	(41)	(145)	(124)
Amortization of prior service costs (credits)		1	1	1
Amortization of net loss (gain)	4	20	13	63
Curtailment loss		2	1	2
Net periodic benefit cost	19	45	60	136
Postretirement Benefit Plans [Member]
Components of net periodic benefit cost:
Service cost	(2)	1		3
Interest cost	4	2	8	5
Expected return on plan assets	(1)		(3)	(2)
Amortization of prior service costs (credits)		(1)	(1)	(2)
Amortization of net loss (gain)	(1)		(2)	1
Curtailment loss	(1)		(1)
Net periodic benefit cost	$ (1)	$ 2	$ 1	$ 5