Pension, Other Postretirement Benefits and Savings Plans - Selected Pension Plan Information (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
United States
All plans:
Accumulated benefit obligation	$ 5,320	$ 5,275
Plans not fully-funded:
Projected benefit obligation	5,329	5,282
Accumulated benefit obligation	5,318	5,273
Fair value of plan assets	4,976	4,970
Non-U.S.
All plans:
Accumulated benefit obligation	3,017	2,792
Plans not fully-funded:
Projected benefit obligation	945	911
Accumulated benefit obligation	887	862
Fair value of plan assets	$ 302	$ 327

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Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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Amount of accumulated benefit obligation for defined benefit pension plan with accumulated benefit obligation in excess of plan assets.

+ 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 (b)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e2417-114920

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- Definition

Fair value of plan assets for defined benefit pension plan with accumulated benefit obligation in excess of plan assets.

+ References

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- Definition

Amount of projected benefit obligation for defined benefit pension plan with accumulated benefit obligation in excess of plan assets.

+ 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=77993564&loc=d3e4179-114921

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