Pension, Retiree Medical and Savings Plans (Components of Benefit Expense) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
United States Pension Plan of US Entity, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Pre-tax non-cash settlement charge		$ 242		$ 141
Service cost		393	$ 435	393
Interest cost		484	546	580
Expected return on plan assets		(834)	(850)	(784)
Amortization of prior service (credit)/cost		(1)	(3)	21
Amortization of net loss/(gain)		168	205	175
Gross total		210	333	385
Settlement/curtailment loss/(gain) (a)	[1]	245		141
Special termination benefits		11	18	24
Total		466	351	550
Pension-related settlement, after-tax		162
International
Defined Benefit Plan Disclosure [Line Items]
Service cost		80	99	98
Interest cost		94	115	131
Expected return on plan assets		(163)	(174)	(176)
Amortization of net loss/(gain)		40	71	53
Gross total		51	111	106
Settlement/curtailment loss/(gain) (a)	[1]	9	3	7
Special termination benefits		1	1
Total		61	115	113
Retiree Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost		31	35	36
Interest cost		41	52	58
Expected return on plan assets		(24)	(27)	(27)
Amortization of prior service (credit)/cost		(38)	(39)	(28)
Amortization of net loss/(gain)		(1)	2	(4)
Gross total		9	23	35
Settlement/curtailment loss/(gain) (a)	[1]	(14)
Special termination benefits		1	1	3
Total		$ (4)	$ 24	$ 38

[1] U.S. includes a settlement charge of $242 million related to the group annuity contract purchase in 2016 and a pension lump sum settlement charge of $141 million in 2014. See additional unaudited information in “Items Affecting Comparability” in Management’s Discussion and Analysis of Financial Condition and Results of Operations.