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Postretirement benefits Schedule of Assumptions Used to determine net periodic benefit costs(Details) | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Pension Plan [Member] | UNITED STATES |  |  |
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] |  |  |
Rate of Compensation Increase | 4.00% | 4.00% |
Expected Long-term Return on Assets | 7.00% | 7.00% |
Pension Plan [Member] | UNITED STATES | Service Cost [Member] |  |  |
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] |  |  |
Discount Rate | 4.20% | 4.38% |
Pension Plan [Member] | UNITED STATES | Interest Cost [Member] |  |  |
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] |  |  |
Discount Rate | 3.53% | 3.59% |
Pension Plan [Member] | Non-US [Member] |  |  |
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] |  |  |
Discount Rate |  |  | 3.51%
Rate of Compensation Increase | 3.57% | 3.33% | 3.09%
Expected Long-term Return on Assets | 4.23% | 4.79% | 4.81%
Pension Plan [Member] | Non-US [Member] | Service Cost [Member] |  |  |
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] |  |  |
Discount Rate | 3.55% | 3.85% |
Pension Plan [Member] | Non-US [Member] | Interest Cost [Member] |  |  |
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] |  |  |
Discount Rate | 2.61% | 3.44% |
Other Postretirement Benefits Plan [Member] |  |  |
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] |  |  |
Expected Long-term Return on Assets | 3.00% | 6.34% |
Other Postretirement Benefits Plan [Member] | Service Cost [Member] |  |  |
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] |  |  |
Discount Rate | 2.84% | 4.32% |
Other Postretirement Benefits Plan [Member] | Interest Cost [Member] |  |  |
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] |  |  |
Discount Rate | 2.44% | 4.02% |

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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 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 + Details
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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 + Details
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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 + Details
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