Pension and Other Postretirement Benefit Plans (PBO and Fair Value of Plan Assets) (Details) - Pension Benefits - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
United States Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plan [Line Items]
Projected benefit obligation	$ 2,718	$ 2,622
Fair value of plan assets	2,547	2,409
Foreign Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plan [Line Items]
Projected benefit obligation	951	844
Fair value of plan assets	$ 546	$ 491

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2417-114920

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- Definition

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

+ References

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- Definition

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+ References

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