Pension, Retiree Medical and Savings Plans (Selected Financial Information for Pension and Retiree Medical Plans) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
Components of the increase/(decrease) in net loss/(gain) included in accumulated other comprehensive loss
Amortization and settlement of (losses)/gains	[1]	$ (209)	$ (281)	$ (226)
Pension Plans, Defined Benefit
Change in fair value of plan assets
Employer contributions/funding		659	162	591
United States Pension Plan of US Entity, Defined Benefit
Change in projected benefit liability
Liability at beginning of year		13,033	13,409
Service cost		393	435	393
Interest cost		484	546	580
Plan amendments		18	16
Experience loss/(gain)		614	(583)
Benefit payments		(347)	(808)
Settlement/curtailment		(1,014)
Special termination benefits		11	18
Liability at end of year		13,192	13,033	13,409
Change in fair value of plan assets
Fair value at beginning of year		11,397	12,224
Actual return on plan assets		880	(85)
Employer contributions/funding		541	66
Benefit payments		(347)	(808)
Defined Benefit Plan, Settlements, Plan Assets		(1,013)
Fair value at end of year		11,458	11,397	12,224
Funded status		(1,734)	(1,636)
Amounts recognized
Other current liabilities		(42)	(47)
Other liabilities		(1,692)	(1,589)
Net amount recognized		(1,734)	(1,636)
Amounts included in accumulated other comprehensive loss (pre-tax)
Net loss/(gain)		3,220	3,065
Prior service cost/(credit)		20	1
Total		3,240	3,066
Components of the increase/(decrease) in net loss/(gain) included in accumulated other comprehensive loss
Change in discount rate		296	(593)
Employee-related assumption changes		5	(35)
Liability-related experience different from assumptions		318	51
Actual asset return different from expected return		(46)	935
Amortization and settlement of (losses)/gains		(413)	(205)
Other, including foreign currency adjustments		(5)	(6)
Total		155	147
Accumulated benefit obligation at end of year		12,211	12,077
International
Change in projected benefit liability
Liability at beginning of year		2,872	3,247
Service cost		80	99	98
Interest cost		94	115	131
Plan amendments			1
Participant contributions		2	2
Experience loss/(gain)		560	(221)
Benefit payments		(83)	(89)
Settlement/curtailment		(19)	(19)
Special termination benefits		1	1
Foreign currency adjustment		(383)	(264)
Liability at end of year		3,124	2,872	3,247
Change in fair value of plan assets
Fair value at beginning of year		2,823	3,002
Actual return on plan assets		409	77
Employer contributions/funding		118	96
Participant contributions		2	2
Benefit payments		(83)	(89)
Defined Benefit Plan, Settlements, Plan Assets		(22)	(16)
Foreign currency adjustment		(353)	(249)
Fair value at end of year		2,894	2,823	3,002
Funded status		(230)	(49)
Amounts recognized
Other assets		51	56
Other current liabilities		(1)	(1)
Other liabilities		(280)	(104)
Net amount recognized		(230)	(49)
Amounts included in accumulated other comprehensive loss (pre-tax)
Net loss/(gain)		884	733
Prior service cost/(credit)		(5)	(7)
Total		879	726
Components of the increase/(decrease) in net loss/(gain) included in accumulated other comprehensive loss
Change in discount rate		554	(150)
Employee-related assumption changes		8	6
Liability-related experience different from assumptions		(2)	(77)
Actual asset return different from expected return		(246)	97
Amortization and settlement of (losses)/gains		(46)	(77)
Other, including foreign currency adjustments		(117)	(69)
Total		151	(270)
Accumulated benefit obligation at end of year		2,642	2,453
Retiree Medical Plan
Change in projected benefit liability
Liability at beginning of year		1,300	1,439
Service cost		31	35	36
Interest cost		41	52	58
Plan amendments		(15)
Experience loss/(gain)		(51)	(115)
Benefit payments		(100)	(102)
Special termination benefits		1	1
Foreign currency adjustment		1	(10)
Liability at end of year		1,208	1,300	1,439
Change in fair value of plan assets
Fair value at beginning of year		354	415
Actual return on plan assets		30	(2)
Employer contributions/funding		36	43	64
Benefit payments		(100)	(102)
Fair value at end of year		320	354	$ 415
Funded status		(888)	(946)
Amounts recognized
Other current liabilities		(54)	(63)
Other liabilities		(834)	(883)
Net amount recognized		(888)	(946)
Amounts included in accumulated other comprehensive loss (pre-tax)
Net loss/(gain)		(193)	(138)
Prior service cost/(credit)		(91)	(127)
Total		(284)	(265)
Components of the increase/(decrease) in net loss/(gain) included in accumulated other comprehensive loss
Change in discount rate		21	(42)
Employee-related assumption changes		(50)	(37)
Liability-related experience different from assumptions		(22)	(36)
Actual asset return different from expected return		(6)	29
Amortization and settlement of (losses)/gains		1	(2)
Other, including foreign currency adjustments		1	(1)
Total		$ (55)	$ (89)

[1] (a)These items are included in the components of net periodic benefit cost for pension and retiree medical plans (see Note 7 for additional details).