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Employee Benefit Plans (Asset Class) (Details) | Dec. 31, 2017
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Pension Plan [Member] | Short-term securities | Maximum [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Target Plan Asset Allocations | 5.00%
Pension Plan [Member] | Short-term securities | Minimum [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Target Plan Asset Allocations | 0.00%
Pension Plan [Member] | Fixed Income Funds [Member] | Maximum [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Target Plan Asset Allocations | 50.00%
Pension Plan [Member] | Fixed Income Funds [Member] | Minimum [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Target Plan Asset Allocations | 35.00%
Pension Plan [Member] | Equity Securities, Canadian [Member] | Maximum [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Target Plan Asset Allocations | 22.00%
Pension Plan [Member] | Equity Securities, Canadian [Member] | Minimum [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Target Plan Asset Allocations | 12.00%
Pension Plan [Member] | Equity Securities, Non Canadian [Member] | Maximum [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Target Plan Asset Allocations | 55.00%
Pension Plan [Member] | Equity Securities, Non Canadian [Member] | Minimum [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Target Plan Asset Allocations | 30.00%
Non-pension Benefit Plans [Member | Short-term securities | Maximum [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Target Plan Asset Allocations | 52.00%
Non-pension Benefit Plans [Member | Short-term securities | Minimum [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Target Plan Asset Allocations | 47.00%
Non-pension Benefit Plans [Member | Equity Securities [Member] | Maximum [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Target Plan Asset Allocations | 53.00%
Non-pension Benefit Plans [Member | Equity Securities [Member] | Minimum [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Target Plan Asset Allocations | 48.00%

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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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 + Details
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