SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - PROPERTY PLANT AND EQUIPMENT (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Sep. 30, 2024
Property Classifications
Total property, plant and equipment	$ 6,954,378	$ 6,496,515
Accumulated depreciation and amortization	(1,144,279)	(1,093,292)
Property, plant and equipment, net	5,810,099	5,403,223
Distribution facilities
Property Classifications
Total property, plant and equipment	$ 3,642,492	3,436,308
Distribution facilities \| Minimum
Property Classifications
Estimated Useful Lives	10 years
Distribution facilities \| Maximum
Property Classifications
Estimated Useful Lives	54 years
Transmission facilities
Property Classifications
Total property, plant and equipment	$ 662,801	656,098
Transmission facilities \| Minimum
Property Classifications
Estimated Useful Lives	28 years
Transmission facilities \| Maximum
Property Classifications
Estimated Useful Lives	40 years
Storage facilities
Property Classifications
Total property, plant and equipment	$ 86,448	86,329
Storage facilities \| Minimum
Property Classifications
Estimated Useful Lives	26 years
Storage facilities \| Maximum
Property Classifications
Estimated Useful Lives	87 years
Solar property
Property Classifications
Total property, plant and equipment	$ 988,445	885,518
Solar property \| Minimum
Property Classifications
Estimated Useful Lives	15 years
Solar property \| Maximum
Property Classifications
Estimated Useful Lives	35 years
Storage and transportation property
Property Classifications
Total property, plant and equipment	$ 960,547	929,850
Storage and transportation property \| Minimum
Property Classifications
Estimated Useful Lives	5 years
Storage and transportation property \| Maximum
Property Classifications
Estimated Useful Lives	55 years
All other property
Property Classifications
Total property, plant and equipment	$ 66,298	62,248
All other property \| Minimum
Property Classifications
Estimated Useful Lives	5 years
All other property \| Maximum
Property Classifications
Estimated Useful Lives	40 years
Construction work in progress
Property Classifications
Total property, plant and equipment	$ 547,347	$ 440,164

Public Utilities And Other Property, Plant and Equipment, Gross

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Public Utilities And Other Property, Plant and Equipment, Net

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Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(8)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(14))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482099/360-10-50-1

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(8))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
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-Subparagraph (SX 210.5-02(13))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482099/360-10-50-1

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