Pension, Retiree Medical and Savings Plans (Selected Financial Information for Pension and Retiree Medical Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015
Pension Plans, Defined Benefit
Change in fair value of plan assets
Employer contributions/funding	$ 164	$ 659	$ 162
Retiree Medical Plan
Change in projected benefit liability
Liability at beginning of year	1,208	1,300
Service cost	28	31	35
Interest cost	36	41	52
Plan amendments	(5)	(15)
Experience loss/(gain)	21	(51)
Special termination benefits	2	1
Other, including foreign currency adjustment	4	1
Liability at end of year	1,187	1,208	1,300
Defined Benefit Plan, Plan Assets, Benefits Paid	107	100
Defined Benefit Plan, Benefit Obligation, Benefits Paid	107	100
Change in fair value of plan assets
Fair value at beginning of year	320	354
Actual return on plan assets	52	30
Employer contributions/funding	56	36	43
Fair value at end of year	321	320	354
Funded status	(866)	(888)
Amounts recognized
Other current liabilities	(75)	(54)
Other liabilities	(791)	(834)
Net amount recognized	(866)	(888)
Amounts included in accumulated other comprehensive loss (pre-tax)
Net loss/(gain)	(189)	(193)
Prior service cost/(credit)	(71)	(91)
Total	(260)	(284)
Changes recognized in net loss/(gain) included in other comprehensive loss
Net loss/(gain) arising in current year	(9)	(57)
Amortization and settlement recognition	12	1
Foreign currency translation loss/(gain)	1	1
Total	4	(55)
Domestic Plan [Member]
Change in projected benefit liability
Liability at beginning of year	13,192	13,033
Service cost	401	393	435
Interest cost	468	484	546
Plan amendments	10	18
Experience loss/(gain)	1,529	614
Settlement/curtailment	(58)	(1,014)
Special termination benefits	60	11
Liability at end of year	14,777	13,192	13,033
Defined Benefit Plan, Plan Assets, Benefits Paid	825	347
Defined Benefit Plan, Benefit Obligation, Benefits Paid	825	347
Change in fair value of plan assets
Fair value at beginning of year	11,458	11,397
Actual return on plan assets	1,935	880
Employer contributions/funding	60	541
Defined Benefit Plan, Plan Assets, Payment for Settlement	(46)	(1,013)
Fair value at end of year	12,582	11,458	11,397
Funded status	(2,195)	(1,734)
Amounts recognized
Other assets	286
Other current liabilities	(74)	(42)
Other liabilities	(2,407)	(1,692)
Net amount recognized	(2,195)	(1,734)
Amounts included in accumulated other comprehensive loss (pre-tax)
Net loss/(gain)	3,520	3,220
Prior service cost/(credit)	29	20
Total	3,549	3,240
Changes recognized in net loss/(gain) included in other comprehensive loss
Net loss/(gain) arising in current year	431	568
Amortization and settlement recognition	(131)	(413)
Total	300	155
Accumulated benefit obligation at end of year	13,732	12,211
Foreign Plan [Member]
Change in projected benefit liability
Liability at beginning of year	3,124	2,872
Service cost	91	80	99
Interest cost	89	94	115
Plan amendments	2
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant	2	2
Experience loss/(gain)	5	560
Settlement/curtailment	(22)	(19)
Special termination benefits		1
Other, including foreign currency adjustment	303	(383)
Liability at end of year	3,490	3,124	2,872
Defined Benefit Plan, Plan Assets, Benefits Paid	104	83
Defined Benefit Plan, Benefit Obligation, Benefits Paid	104	83
Change in fair value of plan assets
Fair value at beginning of year	2,894	2,823
Participant contributions	2	2
Actual return on plan assets	288	409
Employer contributions/funding	104	118
Defined Benefit Plan, Plan Assets, Payment for Settlement	(18)	(22)
Other, including foreign currency adjustment	294	(353)
Fair value at end of year	3,460	2,894	$ 2,823
Funded status	(30)	(230)
Amounts recognized
Other assets	85	51
Other current liabilities	(1)	(1)
Other liabilities	(114)	(280)
Net amount recognized	(30)	(230)
Amounts included in accumulated other comprehensive loss (pre-tax)
Net loss/(gain)	782	884
Prior service cost/(credit)	(3)	(5)
Total	779	879
Changes recognized in net loss/(gain) included in other comprehensive loss
Net loss/(gain) arising in current year	(115)	314
Amortization and settlement recognition	(60)	(46)
Foreign currency translation loss/(gain)	73	(117)
Total	(102)	151
Accumulated benefit obligation at end of year	$ 2,985	$ 2,642