Defined Benefit Postretirement Plans and Defined Contribution Plan - Plan Assumptions (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Assumptions Used In Calculations [Line Items]
Increase (Decrease) in Obligation, Other Postretirement Benefits	$ 99
UNITED STATES
Weighted average assumptions used to determine benefit obligation:
Discount rate	4.26%	3.55%	4.02%
Rate of compensation increase	4.00%	4.00%	4.00%
Weighted average assumptions used to determine net periodic benefit cost:
Discount rate	3.88%	3.86%	3.66%
Expected long-term return on plan assets	6.50%	6.50%	6.75%
Rate of compensation increase	4.00%	4.00%	4.00%
Foreign Plan [Member]
Weighted average assumptions used to determine benefit obligation:
Discount rate	2.90%	2.50%	2.70%
Rate of compensation increase	0.00%	0.00%	0.00%
Weighted average assumptions used to determine net periodic benefit cost:
Discount rate	2.50%	2.70%	3.90%
Expected long-term return on plan assets	3.70%	4.50%	5.50%
Rate of compensation increase	0.00%	0.00%	0.00%
Other Postretirement Benefit Plans, Defined Benefit [Member]
Weighted average assumptions used to determine benefit obligation:
Discount rate	4.09%	3.54%	3.98%
Rate of compensation increase	4.00%	4.00%	4.00%
Weighted average assumptions used to determine net periodic benefit cost:
Discount rate	3.54%	3.98%	4.36%
Expected long-term return on plan assets	0.00%	0.00%	0.00%
Rate of compensation increase	4.00%	4.00%	4.00%

Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

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

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- Definition

Weighted average rate increase of compensation, used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.

+ 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 (k)(2)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan.

+ References

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- Definition

Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.

+ 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 (k)(3)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

Weighted average rate of compensation increase used to determine net periodic benefit cost of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.

+ 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 (k)(2)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount of increase (decrease) in obligation for other postretirement benefits. Includes, but is not limited to, defined benefit and defined contribution plans. Excludes pension benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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