Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Property, Plant and Equipment
Utility	$ 6,520	$ 6,082
Non-utility	7,153	7,046
Total property, plant and equipment	13,673	13,128
Distribution
Property, Plant and Equipment
Utility	5,595	5,204
Transmission
Property, Plant and Equipment
Utility	125	123
General and other
Property, Plant and Equipment
Utility	706	660
Work in process
Property, Plant and Equipment
Utility	94	95
Non-utility	258	156
Land
Property, Plant and Equipment
Non-utility	172	174
Buildings and improvements
Property, Plant and Equipment
Non-utility	$ 429	418
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	$ 233	238
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	$ 3,985	3,903
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	$ 48	190
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	$ 1,598	1,577
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	$ 430	$ 390
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
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-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://www.xbrl.org/2003/role/disclosureRef
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