Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Millions	Sep. 30, 2023	Sep. 30, 2022
Property, Plant and Equipment
Utility	$ 6,082	$ 5,550
Non-utility	7,046	6,656
Total property, plant and equipment	13,128	12,206
Distribution
Property, Plant and Equipment
Utility	5,204	4,746
Transmission
Property, Plant and Equipment
Utility	123	123
General and other
Property, Plant and Equipment
Utility	660	557
Work in process
Property, Plant and Equipment
Utility	95	124
Non-utility	156	53
Land
Property, Plant and Equipment
Non-utility	174	179
Buildings and improvements
Property, Plant and Equipment
Non-utility	$ 418	426
Buildings and improvements \| Minimum
Property, Plant and Equipment
Estimated Useful Life	10 years
Buildings and improvements \| Maximum
Property, Plant and Equipment
Estimated Useful Life	40 years
Transportation equipment
Property, Plant and Equipment
Non-utility	$ 238	234
Transportation equipment \| Minimum
Property, Plant and Equipment
Estimated Useful Life	3 years
Transportation equipment \| Maximum
Property, Plant and Equipment
Estimated Useful Life	10 years
Equipment, primarily cylinders and tanks
Property, Plant and Equipment
Non-utility	$ 3,903	3,645
Equipment, primarily cylinders and tanks \| Minimum
Property, Plant and Equipment
Estimated Useful Life	5 years
Equipment, primarily cylinders and tanks \| Maximum
Property, Plant and Equipment
Estimated Useful Life	30 years
Electric generation
Property, Plant and Equipment
Non-utility	$ 190	216
Electric generation \| Minimum
Property, Plant and Equipment
Estimated Useful Life	25 years
Electric generation \| Maximum
Property, Plant and Equipment
Estimated Useful Life	40 years
Pipeline and related assets
Property, Plant and Equipment
Non-utility	$ 1,577	1,523
Pipeline and related assets \| Minimum
Property, Plant and Equipment
Estimated Useful Life	25 years
Pipeline and related assets \| Maximum
Property, Plant and Equipment
Estimated Useful Life	40 years
Other
Property, Plant and Equipment
Non-utility	$ 390	$ 380
Other \| Minimum
Property, Plant and Equipment
Estimated Useful Life	1 year
Other \| Maximum
Property, Plant and Equipment
Estimated Useful Life	12 years

Amount, before accumulated depreciation and amortization, of property, plant, and equipment and finance lease right-of-use asset.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
-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

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(18))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (a)
-SubTopic 20
-Topic 842
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479041/842-20-45-1

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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