Pension and Other Postretirement Benefits (Details 8) - Pension Plan [Member]	Dec. 31, 2017
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
The weighted-average target investment allocations in equity securities	65.00%
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
The weighted-average target investment allocations in equity securities	35.00%

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.

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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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant