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Pension Plans - Percentage of Total Plan Assets (Details) - Pension Plan | Sep. 30, 2020 | Sep. 30, 2019
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Defined Benefit Plan Disclosure [Line Items] |  |
Asset Category | 100.00% | 100.00%
Equity Securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset Category | 33.00% | 32.00%
Fixed Income Securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset Category | 34.00% | 46.00%
Commodity Option |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset Category | 11.00% | 2.00%
Insurance Company |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset Category | 13.00% | 12.00%
Options |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset Category | 1.00% | 0.00%
Cash |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Asset Category | 8.00% | 8.00%

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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 actual 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/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
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