Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2022	Sep. 30, 2021
Property, Plant and Equipment
Utility	$ 5,550	$ 5,022
Non-utility	6,656	6,486
Total property, plant and equipment	12,206	11,508
Distribution
Property, Plant and Equipment
Utility	4,746	4,306
Transmission
Property, Plant and Equipment
Utility	123	111
General and other
Property, Plant and Equipment
Utility	557	507
Work in process
Property, Plant and Equipment
Utility	124	98
Non-utility	53	76
Land
Property, Plant and Equipment
Non-utility	179	186
Buildings and improvements
Property, Plant and Equipment
Non-utility	$ 426	436
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	$ 234	232
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	$ 3,645	3,785
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	$ 216	211
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	$ 1,523	1,218
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	$ 380	$ 342
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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(18))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=123391704&loc=SL77918627-209977

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