Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 25, 2016	Mar. 27, 2015
Pension Plans [Member]
Components of net periodic benefit cost:
Service cost	$ 27	$ 32
Interest cost	35	37
Expected return on plan assets	$ (51)	(52)
Amortization of prior service costs (credits)		1
Amortization of net loss	$ 13	17
Net periodic benefit cost	24	35
Postretirement Benefit Plans [Member]
Components of net periodic benefit cost:
Service cost	1	1
Interest cost	1	2
Expected return on plan assets	(1)	(1)
Amortization of prior service costs (credits)	$ (1)	$ (1)
Amortization of net loss
Net periodic benefit cost		$ 1