An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Expected Long-Term Rate of Return on Plan Assets
-URI http://asc.fasb.org/extlink&oid=6512046

Reference 2: 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=65897934&loc=d3e1928-114920

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Target allocation of investments of this type to total plan assets presented on a weighted average basis.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)(i)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2446-114920

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-Name Accounting Standards Codification
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-SubTopic 20
-Section 50
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Retirement-Related Benefits - Investment Strategy (Details) - U.S. Pension Plans	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2017	Dec. 31, 2015
Retirement-related benefits disclosures
Expected long-term returns on plan assets (as a percent)			7.00%
Expected
Retirement-related benefits disclosures
Expected long-term returns on plan assets (as a percent)		6.25%
Equity securities
Retirement-related benefits disclosures
Target allocation (as a percent)	21.00%		34.00%
Other investments
Retirement-related benefits disclosures
Target allocation (as a percent)	9.00%		10.00%
Debt securities
Retirement-related benefits disclosures
Target allocation (as a percent)	70.00%		56.00%