Property, Plant and Equipment (Details) - USD ($) $ in Millions	Sep. 30, 2017	Sep. 30, 2016
Property, Plant and Equipment
Utility	$ 3,285.3	$ 2,998.9
Non-utility	5,564.6	5,346.4
Total property, plant and equipment	8,849.9	8,345.3
Distribution
Property, Plant and Equipment
Utility	2,835.3	2,634.2
Transmission
Property, Plant and Equipment
Utility	96.4	93.5
General and other
Property, Plant and Equipment
Utility	241.0	167.3
Land
Property, Plant and Equipment
Non-utility	180.1	169.9
Buildings and improvements
Property, Plant and Equipment
Non-utility	351.2	382.2
Transportation equipment
Property, Plant and Equipment
Non-utility	289.3	301.7
Equipment, primarily cylinders and tanks
Property, Plant and Equipment
Non-utility	3,529.4	3,421.5
Electric generation
Property, Plant and Equipment
Non-utility	310.0	309.4
Pipeline and related assets
Property, Plant and Equipment
Non-utility	454.5	235.8
Work in process
Property, Plant and Equipment
Utility	112.6	103.9
Non-utility	95.3	201.6
Other
Property, Plant and Equipment
Non-utility	$ 354.8	$ 324.3

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.13)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
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-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

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