Retirement and Employee Benefit Plans (Schedule of Allocation of Plan Assets) (Details) - Pension Benefits [Member]	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Target asset allocations	100.00%
Actual asset allocations	100.00%
Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocations	28.00%
Actual asset allocations	27.00%
Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocations	2.00%
Actual asset allocations	2.00%
U.S. Equity [Member] \| Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocations	35.00%
Actual asset allocations	36.00%
Non-U.S. Developed Equity [Member] \| Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocations	30.00%
Actual asset allocations	30.00%
Emerging Markets Equity [Member] \| Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocations	5.00%
Actual asset allocations	5.00%
Opportunistic [Member] \| Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocations
Actual asset allocations

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- Definition

Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one 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 (d)(5)(i)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

+ References

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)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e2446-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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