Pension, Retiree Medical and Savings Plans (Selected Information About Plans with Liability for Service to Date and Total Benefit Liability in Excess of Plan Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
United States Pension Plan of US Entity, Defined Benefit
Selected information for plans with accumulated benefit obligation in excess of plan assets (a)
Liability for service to date	$ (12,211)	$ (6,536)
Fair value of plan assets	11,458	5,698
Selected information for plans with projected benefit liability in excess of plan assets
Benefit liability	(13,192)	(13,033)
Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets	11,458	11,397
Defined Benefit Plan, Fair Value of Plan Assets	11,458	11,397	$ 12,224
International
Selected information for plans with accumulated benefit obligation in excess of plan assets (a)
Liability for service to date	(134)	(155)
Fair value of plan assets	110	112
Selected information for plans with projected benefit liability in excess of plan assets
Benefit liability	(2,773)	(511)
Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets	2,492	406
Defined Benefit Plan, Fair Value of Plan Assets	2,894	2,823	3,002
Retiree Medical Plan
Selected information for plans with projected benefit liability in excess of plan assets
Benefit liability	(1,208)	(1,300)
Defined Benefit Plan, Fair Value of Plan Assets	$ 320	$ 354	$ 415

Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 30
-Section 35
-Paragraph 50
-URI http://asc.fasb.org/extlink&oid=64937038&loc=d3e12355-114930

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Plan Assets
-URI http://asc.fasb.org/extlink&oid=6749337

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Plan Assets
-URI http://asc.fasb.org/extlink&oid=6520858

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- Definition

If aggregate disclosures are presented, the aggregate pension accumulated benefit obligation for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=73719040&loc=d3e4179-114921

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
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-Paragraph 3
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If aggregate disclosures are presented, the aggregate fair value of plan assets for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

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If aggregate disclosures are presented, the aggregate benefit obligation for plans with benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2417-114920

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If aggregate disclosures are presented, the aggregate fair value of plan assets for plans with benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

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