Revenue recognition changes in accrued revenue under alternative revenue programs.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The total amount of operating revenues recognized during the period.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of regulated gas operating revenues recognized during the period.

+ References

No definition available.

+ Details

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- Definition

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9038-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130545-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8906-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130543-203045

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9054-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9031-108599

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI https://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of unregulated operating revenues recognized during the period.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

Note 2 - Revenue - Disaggregated of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Operating Revenues	$ 814.0	$ 814.0	$ 555.4	$ 555.4
Consolidation, Eliminations [Member]
Operating Revenues	(12.3)		(12.6)
Gas Utility [Member] \| Operating Segments [Member]
Operating Revenues	733.0		503.5
Gas Marketing [Member] \| Operating Segments [Member]
Operating Revenues	74.1		47.9
Midstream [Member] \| Operating Segments [Member]
Operating Revenues	15.2		12.9
Other Segments [Member]
Operating Revenues	4.0		3.7
Spire Missouri [Member]
Operating Revenues	541.2		347.9
Spire Missouri [Member] \| Gas Utility [Member] \| Operating Segments [Member]
Revenue	539.7		331.3
Changes in accrued revenue under alternative revenue programs	1.5		16.6
Spire Missouri [Member] \| Gas Utility [Member] \| Operating Segments [Member] \| Residential [Member]
Revenue	400.6		247.1
Spire Missouri [Member] \| Gas Utility [Member] \| Operating Segments [Member] \| Commercial and Industrial [Member]
Revenue	122.9		68.2
Spire Missouri [Member] \| Gas Utility [Member] \| Operating Segments [Member] \| Transportation [Member]
Revenue	9.1		9.2
Spire Missouri [Member] \| Gas Utility [Member] \| Operating Segments [Member] \| Off-system and Other Incentive [Member]
Revenue	5.1		4.5
Spire Missouri [Member] \| Gas Utility [Member] \| Operating Segments [Member] \| Other Customer Revenue [Member]
Revenue	2.0		2.3
Spire Alabama Inc [Member]
Operating Revenues	152.4		126.6
Spire Alabama Inc [Member] \| Gas Utility [Member] \| Operating Segments [Member]
Revenue	152.8		126.7
Changes in accrued revenue under alternative revenue programs	(0.4)		(0.1)
Spire Alabama Inc [Member] \| Gas Utility [Member] \| Operating Segments [Member] \| Residential [Member]
Revenue	96.3		80.1
Spire Alabama Inc [Member] \| Gas Utility [Member] \| Operating Segments [Member] \| Commercial and Industrial [Member]
Revenue	33.6		26.0
Spire Alabama Inc [Member] \| Gas Utility [Member] \| Operating Segments [Member] \| Transportation [Member]
Revenue	19.3		19.4
Spire Alabama Inc [Member] \| Gas Utility [Member] \| Operating Segments [Member] \| Off-system and Other Incentive [Member]
Revenue	2.4		0.4
Spire Alabama Inc [Member] \| Gas Utility [Member] \| Operating Segments [Member] \| Other Customer Revenue [Member]
Revenue	1.2		0.8
Spire [Member]
Operating Revenues	814.0		555.4
Spire [Member] \| Operating Segments [Member]
Operating Revenues	826.3		568.0
Spire [Member] \| Consolidation, Eliminations [Member]
Operating Revenues	(12.3)
Spire [Member] \| Segment Reconciling Items [Member]
Operating Revenues			(12.6)
Spire [Member] \| Gas Utility [Member] \| Operating Segments [Member]
Revenue	731.5		485.4
Changes in accrued revenue under alternative revenue programs	1.5		18.1
Total Gas Utility operating revenues	733.0		503.5
Spire [Member] \| Gas Utility [Member] \| Operating Segments [Member] \| Residential [Member]
Revenue	518.0		342.0
Spire [Member] \| Gas Utility [Member] \| Operating Segments [Member] \| Commercial and Industrial [Member]
Revenue	170.6		103.8
Spire [Member] \| Gas Utility [Member] \| Operating Segments [Member] \| Transportation [Member]
Revenue	30.9		31.2
Spire [Member] \| Gas Utility [Member] \| Operating Segments [Member] \| Off-system and Other Incentive [Member]
Revenue	7.6		4.8
Spire [Member] \| Gas Utility [Member] \| Operating Segments [Member] \| Other Customer Revenue [Member]
Revenue	4.4		3.6
Spire [Member] \| Gas Marketing [Member] \| Operating Segments [Member]
Unregulated Operating Revenue	74.1		47.9
Spire [Member] \| Midstream [Member] \| Operating Segments [Member]
Unregulated Operating Revenue	15.2		12.9
Spire [Member] \| Other Segments [Member] \| Operating Segments [Member]
Unregulated Operating Revenue	$ 4.0		$ 3.7