Components of Pretax Net Periodic Benefit Costs (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 25, 2012
Qualified defined benefit pension plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 286	$ 264
Interest cost	450	471
Expected return on plan assets	(622)	(547)
Recognized net actuarial losses	353	279
Amortization of prior service cost (credit)	20	18
Total net periodic benefit cost	487	485
Retiree medical and life insurance plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	7	7
Interest cost	29	33
Expected return on plan assets	(36)	(33)
Recognized net actuarial losses	11	8
Amortization of prior service cost (credit)	(5)	(3)
Total net periodic benefit cost	$ 6	$ 12