SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - PROPERTY PLANT AND EQUIPMENT (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2022	Sep. 30, 2021
Property Classifications
Total property, plant and equipment	$ 5,515,716	$ 4,997,049
Accumulated depreciation and amortization	(865,790)	(783,536)
Property, plant and equipment, net	4,649,926	4,213,513
Regulated \| Distribution facilities
Property Classifications
Total property, plant and equipment	$ 2,797,936	2,558,651
Regulated \| Distribution facilities \| Minimum
Property Classifications
Estimated Useful Lives	10 years
Regulated \| Distribution facilities \| Maximum
Property Classifications
Estimated Useful Lives	54 years
Regulated \| Transmission facilities
Property Classifications
Total property, plant and equipment	$ 649,241	643,942
Regulated \| Transmission facilities \| Minimum
Property Classifications
Estimated Useful Lives	28 years
Regulated \| Transmission facilities \| Maximum
Property Classifications
Estimated Useful Lives	42 years
Regulated \| Storage facilities
Property Classifications
Total property, plant and equipment	$ 85,449	79,892
Regulated \| Storage facilities \| Minimum
Property Classifications
Estimated Useful Lives	35 years
Regulated \| Storage facilities \| Maximum
Property Classifications
Estimated Useful Lives	86 years
Unregulated \| Solar property
Property Classifications
Total property, plant and equipment	$ 710,224	675,376
Unregulated \| Solar property \| Minimum
Property Classifications
Estimated Useful Lives	20 years
Unregulated \| Solar property \| Maximum
Property Classifications
Estimated Useful Lives	35 years
Unregulated \| Storage and transportation property
Property Classifications
Total property, plant and equipment	$ 850,186	433,678
Unregulated \| Storage and transportation property \| Minimum
Property Classifications
Estimated Useful Lives	5 years
Unregulated \| Storage and transportation property \| Maximum
Property Classifications
Estimated Useful Lives	50 years
Unregulated \| All other property
Property Classifications
Total property, plant and equipment	$ 60,914	57,968
Unregulated \| All other property \| Minimum
Property Classifications
Estimated Useful Lives	5 years
Unregulated \| All other property \| Maximum
Property Classifications
Estimated Useful Lives	40 years
Unregulated \| Construction work in progress
Property Classifications
Total property, plant and equipment	$ 361,766	$ 547,542

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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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(14))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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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.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(13))
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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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