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DERIVATIVE INSTRUMENTS - INCOME STATEMENT RELATED DISCLOSURES (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Mar. 31, 2021 | Mar. 31, 2020 | Mar. 31, 2021 | Mar. 31, 2020
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Amount of (losses) gains recognized in income on derivatives | $ 11,781 | $ 33,048 | $ 59,934 | $ 87,682
Energy Services | Physical commodity contracts | Operating revenues |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Amount of (losses) gains recognized in income on derivatives | 36,419 | 12,096 | 41,671 | 21,932
Energy Services | Physical commodity contracts | Natural gas purchases |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Amount of (losses) gains recognized in income on derivatives | 2,650 | (1,892) | (2,404) | (3,302)
Energy Services | Financial commodity contracts | Natural gas purchases |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Amount of (losses) gains recognized in income on derivatives | (27,315) | 23,319 | 20,440 | 69,412
Energy Services | Foreign currency contracts | Natural gas purchases |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Amount of (losses) gains recognized in income on derivatives | 27 | (475) | 227 | (360)
Natural Gas Distribution |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Amount of (losses) gains recognized in income on derivatives | 1,736 | (17,917) | (2,194) | (18,165)
Natural Gas Distribution | Physical commodity contracts |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Amount of (losses) gains recognized in income on derivatives | 1,091 | 209 | 1,433 | 1,049
Natural Gas Distribution | Financial commodity contracts |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Amount of (losses) gains recognized in income on derivatives | 645 | (11,434) | (3,627) | (12,522)
Natural Gas Distribution | Interest rate contracts |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Amount of (losses) gains recognized in income on derivatives | $ 0 | $ (6,692) | $ 0 | $ (6,692)

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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5618551-113959 + Details
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