Benefit Plans - Weighted Average Assumptions for Net Periodic Cost (Details)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost
Immediate trend rate	6.84%	7.28%
Ultimate trend rate	4.50%	4.50%
Year that the rate reaches ultimate trend rate	2035	2035
Defined Benefit Pension Plans \| U.S.
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost
Discount rate	4.24%	4.02%	4.09%
Rate of compensation increase	3.00%	3.10%
Expected return on assets	6.37%	6.34%
Defined Benefit Pension Plans \| U.S. \| Eco Services Hourly Pension Plan
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost
Rate of compensation increase			3.00%
Defined Benefit Pension Plans \| Foreign
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost
Discount rate	2.99%	5.16%	0.00%
Rate of compensation increase	2.97%	3.95%	0.00%
Expected return on assets	3.58%	5.62%	0.00%
Supplemental Retirement Plans
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost
Discount rate	3.90%	3.40%
Other Postretirement Benefits Plans
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost
Discount rate	3.74%	3.92%	4.36%

Defined Benefit Plan, Benefit Costs, Health Care Cost Trend Rate Assumed, Next Fiscal Year

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- Definition

Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate, Benefit Cost

+ References

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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

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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

Ultimate trend rate for health care cost for defined benefit postretirement 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 (l)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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