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Retirement Plans (Plan's Allocated Target and Ranges and Actual Weighted Average Asset Allocation by Investment Categories) (Details) | 12 Months Ended
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Dec. 31, 2013 | Dec. 31, 2012
Actual percentage | 100.00% |  | 100.00% |
Maximum percentage of equity security value of total plans portfolio value that is allowed | 8.00% |  |  |
Maximum percentage of any corporation outstanding shares that is allowed for retirement income plan equity portfolio | 5.00% |  |  |
International Securities [Member] |  |  |  |
Target percentage | 10.00% |  |  |
Actual percentage | 8.00% |  | 7.00% |
Range minimum |  |  | 4.00% |
Range maximum |  |  | 18.00% |
Large Capitalization Securities [Member] |  |  |  |
Target percentage | 15.00% |  |  |
Actual percentage | 13.00% |  | 15.00% |
Range minimum |  |  | 8.00% |
Range maximum |  |  | 32.00% |
Small And Mid Capitalization Securities [Member] |  |  |  |
Target percentage | 5.00% |  |  |
Actual percentage | 5.00% |  | 7.00% |
Range minimum |  |  | 3.00% |
Range maximum |  |  | 15.00% |
Global Asset Allocation [Member] |  |  |  |
Target percentage | 10.00% |  |  |
Actual percentage | 12.00% |  | 10.00% |
Range minimum |  |  | 0.00% |
Range maximum |  |  | 15.00% |
Partnership Interest [Member] |  |  |  |
Target percentage | 10.00% |  |  |
Actual percentage | 5.00% |  | 6.00% |
Range minimum |  |  | 0.00% |
Range maximum |  |  | 15.00% |
Extended Duration Fixed Maturity [Member] |  |  |  |
Target percentage | 50.00% |  |  |
Actual percentage | 42.00% |  | 24.00% |
Range minimum |  |  | 20.00% |
Range maximum |  |  | 80.00% |
Domestic Core Debt Securities [Member] |  |  |  |
Actual percentage | 0.00% | [1] | 14.00% | [1]
Global bond high yield emerging markets [Member] |  |  |  |
Actual percentage | 12.00% | [1] | 13.00% | [1]
Cash and short term investments [Member] |  |  |  |
Target percentage | 0.00% |  |  |
Actual percentage | 3.00% |  | 4.00% |
Range minimum |  |  | 0.00% |
Range maximum |  |  | 5.00% |
[1] | The Retirement Income Plan currently has fixed maturity security exposures that do not have target and range percentages since these exposures will be phased out over time as we opportunistically migrate from intermediate to long duration fixed maturity security strategies.

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- Definition The maximum percentage of outstanding shares of any one corporation that is allowed for the Retirement Income Plan. + References No definition available. + Details
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- Definition The maximum percentage of any individual security value of the total Retirement Income Plan's portfolio value that is allowed. + References No definition available. + Details
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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 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 Reference 2: 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=28361610&loc=d3e2446-114920 + Details
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- Definition Target allocation maximum percentage 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 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 Reference 2: 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=28361610&loc=d3e2446-114920 + Details
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- Definition Target allocation minimum percentage 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 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 Reference 2: 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=28361610&loc=d3e2446-114920 + Details
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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=28361610&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=28361610&loc=d3e1928-114920 + Details
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