Postretirement Benefit Plans - Target Allocation (Details) - Postretirement Benefit Plans [Member]	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Actual Asset Allocation	100.00%	100.00%
Equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual Asset Allocation	42.00%	51.00%
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual Asset Allocation	58.00%	49.00%
Minimum [Member] \| Equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Current Target Allocation	34.00%
Minimum [Member] \| Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Current Target Allocation	54.00%
Maximum [Member] \| Equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Current Target Allocation	46.00%
Maximum [Member] \| Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Current Target Allocation	66.00%

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- Definition

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

+ 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)(i)
-URI http://asc.fasb.org/extlink&oid=58740216&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)(i)
-URI http://asc.fasb.org/extlink&oid=58740216&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=58740216&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=58740216&loc=d3e1928-114920

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