Spire (SR) 10-Q 1 Feb 24 2024 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Dec. 31, 2023	Jan. 29, 2024
Document Information [Line Items]
Entity Central Index Key	0001126956
Entity Registrant Name	Spire Inc.
Amendment Flag	false
Current Fiscal Year End Date	--09-30
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2024
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Dec. 31, 2023
Document Transition Report	false
Entity File Number	1-16681
Entity Address, Address Line One	700 Market Street
Entity Address, City or Town	St. Louis
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	63101
City Area Code	314
Local Phone Number	342-0500
Entity Incorporation, State or Country Code	MO
Entity Tax Identification Number	74-2976504
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		54,983,397
Spire Missouri [Member]
Document Information [Line Items]
Entity Central Index Key	0000057183
Entity Registrant Name	Spire Missouri Inc.
Amendment Flag	false
Current Fiscal Year End Date	--09-30
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2024
Entity File Number	1-1822
Entity Address, Address Line One	700 Market Street
Entity Address, City or Town	St. Louis
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	63101
City Area Code	314
Local Phone Number	342-0500
Entity Incorporation, State or Country Code	MO
Entity Tax Identification Number	43-0368139
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		25,855
Spire Alabama Inc [Member]
Document Information [Line Items]
Entity Central Index Key	0000003146
Entity Registrant Name	Spire Alabama Inc.
Amendment Flag	false
Current Fiscal Year End Date	--09-30
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2024
Entity File Number	2-38960
Entity Address, Address Line One	605 Richard Arrington Blvd N
Entity Address, City or Town	Birmingham
Entity Address, State or Province	AL
Entity Address, Postal Zip Code	35203
City Area Code	205
Local Phone Number	326-8100
Entity Incorporation, State or Country Code	AL
Entity Tax Identification Number	63-0022000
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		1,972,052
Depositary Shares [Member]
Document Information [Line Items]
Title of 12(b) Security	Depositary Shares, each representing a 1/1,000th interest in a share of 5.90% Series A
Trading Symbol	SR.PRA
Security Exchange Name	NYSE
Common Stock [Member]
Document Information [Line Items]
Title of 12(b) Security	Common Stock $1.00 par value
Trading Symbol	SR
Security Exchange Name	NYSE

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating Revenues	$ 756.6	$ 814
Operating Expenses:
Natural gas	367	419.2
Operation and maintenance	130.7	132.1
Depreciation and amortization	67	62.1
Taxes, other than income taxes	52.7	50.4
Total Operating Expenses	617.4	663.8
Operating Income	139.2	150.2
Interest Expense, Net	50.6	43.6
Other Income, Net	17.5	6
Income Before Income Taxes	106.1	112.6
Income Tax Expense	21	21.6
Net Income	85.1	91
Provision for preferred dividends	3.7	3.7
Income allocated to participating securities	0.1	0.1
Net Income Available to Common Shareholders	$ 81.3	$ 87.2
Weighted Average Number of Common Shares Outstanding:
Basic (in shares)	53.5	52.4
Diluted (in shares)	53.6	52.6
Basic Earnings Per Common Share (in dollars per share)	$ 1.52	$ 1.66
Diluted Earnings Per Common Share (in dollars per share)	$ 1.52	$ 1.66
Operating Revenues	$ 756.6	$ 814
Spire Alabama Inc [Member]
Operating Revenues	142.1	152.4
Operating Expenses:
Natural gas	55.8	69.4
Operation and maintenance	34.2	35.1
Depreciation and amortization	17.9	17
Taxes, other than income taxes	10.2	10.6
Total Operating Expenses	118.1	132.1
Operating Income	24	20.3
Interest Expense, Net	9.3	8.3
Other Income, Net	0.3	0.4
Income Before Income Taxes	15	12.4
Income Tax Expense	3.9	3.2
Net Income	11.1	9.2
Weighted Average Number of Common Shares Outstanding:
Operating Revenues	$ 142.1	$ 152.4

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions		3 Months Ended
		Dec. 31, 2023		Dec. 31, 2022
Net Income		$ 85.1		$ 91
Other Comprehensive Loss, Before Tax:
Net hedging loss arising during the period		(15.4)		(3)
Amounts reclassified into net income		(9)		(0.3)
Net loss on cash flow hedging derivative instruments		(24.4)		(3.3)
Net gain on defined benefit pension and other postretirement plans		0.1		0.1
Net unrealized gain on available for sale securities		0.1		0
Other Comprehensive Loss, Before Tax		(24.2)		(3.2)
Income Tax Benefit Related to Items of Other Comprehensive Loss		(5.7)		(0.8)
Other Comprehensive Loss, Net of Tax		(18.5)		(2.4)
Comprehensive Income		66.6		88.6
Operating Revenues		756.6		814
Operating Expenses:
Natural gas		367		419.2
Operation and maintenance		130.7		132.1
Depreciation and amortization		67		62.1
Taxes, other than income taxes		52.7		50.4
Total Operating Expenses		617.4		663.8
Operating Income		139.2		150.2
Interest Expense, Net		50.6		43.6
Other Income, Net		17.5		6
Income Before Income Taxes		106.1		112.6
Income Tax Expense		21		21.6
Net Income		85.1		91
Other Comprehensive Income, Net of Tax		(18.5)		(2.4)
Comprehensive Income		66.6		88.6
Spire Missouri [Member]
Net Income		57	[1]	47.3
Other Comprehensive Loss, Before Tax:
Other Comprehensive Loss, Net of Tax	[1]	0.1		0.1
Comprehensive Income		57.1		47.4
Operating Revenues		535.4		541.2
Operating Expenses:
Natural gas		292.6		316.7
Operation and maintenance		74.9		77.1
Depreciation and amortization		42.1		38.6
Taxes, other than income taxes		38.5		36.4
Total Operating Expenses		448.1		468.8
Operating Income		87.3		72.4
Interest Expense, Net		27.9		22
Other Income, Net		7.2		5
Income Before Income Taxes		66.6		55.4
Income Tax Expense		9.6		8.1
Net Income		57	[1]	47.3
Other Comprehensive Income, Net of Tax	[1]	0.1		0.1
Comprehensive Income		$ 57.1		$ 47.4
[1]Accumulated other comprehensive income (loss)

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Millions		Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
ASSETS
Utility Plant		$ 8,345	$ 8,210.1	$ 7,769.4
Less: Accumulated depreciation and amortization		2,467.3	2,431.2	2,326.5
Net Utility Plant		5,877.7	5,778.9	5,442.9
Non-utility Property (net of accumulated depreciation and amortization of $76.5, $71.1 and $55.6 at December 31, 2023, September 30, 2023, and December 31, 2022, respectively)		687.1	628.5	508.9
Other Investments		105.5	102.6	93.5
Total Other Property and Investments		792.6	731.1	602.4
Other Property and Investments		792.6	731.1	602.4
Current Assets:
Cash and cash equivalents		4.8	5.6	4.8
Utility		428.8	192.4	479.4
Other		150.6	128.6	334.7
Allowance for credit losses		(35.4)	(32.5)	(34.5)
Delayed customer billings		22	22	26.7
Accounts receivable:
Utility		428.8	192.4	479.4
Other		150.6	128.6	334.7
Allowance for credit losses		(35.4)	(32.5)	(34.5)
Delayed customer billings		22	22	26.7
Inventories:
Natural gas		220.6	223.7	320
Propane gas		8.6	8.6	8.6
Materials and supplies		47.4	47.2	44.1
Regulatory assets		256.4	348.3	269.1
Prepayments		43.3	48.2	31.6
Other current assets		72.8	84.8	145.2
Total Current Assets		1,219.9	1,076.9	1,629.7
Deferred Charges and Other Assets:
Goodwill		1,171.6	1,171.6	1,171.6
Regulatory assets		1,266.9	1,249.2	1,220.7
Other		303	305.9	260.4
Total Deferred Charges and Other Assets		2,741.5	2,726.7	2,652.7
Total Assets		10,631.7	10,313.6	10,327.7
Capitalization:
Preferred stock ($25.00 par value per share; 10.0 million depositary shares authorized, issued and outstanding at December 31, 2023, September 30, 2023, and December 31, 2022)		242	242	242
Common stock (par value $1.00 per share; 70.0 million shares authorized; 55.0 million, 53.2 million, and 52.5 million shares issued and outstanding at December 31, 2023, September 30, 2023, and December 31, 2022, respectively)		55	53.2	52.5
Paid-in capital		1,727.4	1,616.5	1,571.8
Retained earnings		997.3	958	953
Accumulated other comprehensive income		29.1	47.6	44.8
Total Shareholders' Equity		3,050.8	2,917.3	2,864.1
Temporary equity		14.8	16.5	16.2
Long-term debt (less current portion)		3,247.8	3,554	3,156.3
Total Capitalization		6,313.4	6,487.8	6,036.6
Current Liabilities:
Current portion of long-term debt		457	156.6	256.6
Notes payable		1,047.5	955.5	1,227
Accounts payable		293.8	253.1	506.8
Advance customer billings		25	20.9	16.9
Wages and compensation accrued		26.1	47	30.6
Customer deposits		28.8	27.7	28.8
Taxes accrued		64.9	104.1	57.6
Regulatory liabilities		7.1	7.3	3.7
Other current liabilities		260.3	183.2	276.7
Total Current Liabilities		2,210.5	1,755.4	2,404.7
Deferred Credits and Other Liabilities:
Deferred income taxes		760.6	743.7	699.4
Pension and postretirement benefit costs		135.5	137.3	159.3
Asset retirement obligations		583.6	577.4	526.2
Regulatory liabilities		487.2	472.4	344.9
Other noncurrent liabilities		140.9	139.6	156.6
Total Deferred Credits and Other Liabilities		2,107.8	2,070.4	1,886.4
Total Capitalization and Liabilities		10,631.7	10,313.6	10,327.7
Spire Missouri [Member]
ASSETS
Utility Plant		5,080.2	4,964.9	4,632.6
Less: Accumulated depreciation and amortization		1,063.7	1,043.2	1,003.4
Net Utility Plant		4,016.5	3,921.7	3,629.2
Total Other Property and Investments		67.9	65.7	66.5
Other Property and Investments		67.9	65.7	66.5
Current Assets:
Cash and cash equivalents		0	0.8	0
Other		22.2	21.1	28.6
Allowance for credit losses		(28.9)	(26.2)	(28.2)
Delayed customer billings		16.8	17.9	21.5
Accounts receivable:
Other		22.2	21.1	28.6
Allowance for credit losses		(28.9)	(26.2)	(28.2)
Delayed customer billings		16.8	17.9	21.5
Inventories:
Natural gas		141.8	132.8	189.9
Propane gas		8.6	8.6	8.6
Materials and supplies		24.6	24.2	23
Regulatory assets		212.9	293.1	191.2
Prepayments		22.8	26.7	15.8
Total Current Assets		757.4	642.9	813.4
Deferred Charges and Other Assets:
Goodwill		210.2	210.2	210.2
Regulatory assets		630.8	617.6	634.7
Other		146	147.4	106
Total Deferred Charges and Other Assets		987	975.2	950.9
Total Assets		5,828.8	5,605.5	5,460
Capitalization:
Retained earnings		1,049.4	992.4	979.2
Accumulated other comprehensive income		(2.4)	(2.5)	(2.6)
Total Shareholders' Equity	[1]	1,901.9	1,844.8	1,792.8
Long-term debt (less current portion)		1,485.8	1,785.4	1,388.1
Total Capitalization		3,387.7	3,630.2	3,180.9
Paid-in capital and common stock		854.9	854.9	816.2
Current Liabilities:
Current portion of long-term debt		300	0	250
Advance customer billings		14.3	11	5.3
Wages and compensation accrued		14.4	23.6	21.5
Customer deposits		5.9	5.8	6.3
Taxes accrued		26.4	60.3	24.3
Other current liabilities		111.1	48.7	92.9
Total Current Liabilities		1,218.4	786.3	1,238.2
Deferred Credits and Other Liabilities:
Deferred income taxes		545.8	531.8	512.4
Pension and postretirement benefit costs		102	103.3	101.9
Asset retirement obligations		112.2	111.1	111.7
Regulatory liabilities		404.5	389.4	259
Other noncurrent liabilities		58.2	53.4	55.9
Total Deferred Credits and Other Liabilities		1,222.7	1,189	1,040.9
Commitments and Contingencies (Note 11)
Total Capitalization and Liabilities		5,828.8	5,605.5	5,460
Spire Missouri [Member] | Nonrelated Party [Member]
Current Assets:
Utility		335.5	142.6	357.2
Accounts receivable:
Utility		335.5	142.6	357.2
Current Liabilities:
Accounts payable		106.6	85.8	166.6
Spire Missouri [Member] | Related Party [Member]
Current Assets:
Utility		1.1	1.3	5.8
Accounts receivable:
Utility		1.1	1.3	5.8
Current Liabilities:
Notes payable		633.3	540.6	651.2
Accounts payable		6.4	10.5	20.1
Spire Alabama Inc [Member]
ASSETS
Utility Plant		2,879.8	2,862.6	2,755.8
Less: Accumulated depreciation and amortization		1,289.1	1,273	1,196.5
Net Utility Plant		1,590.7	1,589.6	1,559.3
Current Assets:
Cash and cash equivalents		0	1.2	0
Other		5.7	6.6	5.4
Allowance for credit losses		(5.7)	(5.7)	(5.5)
Delayed customer billings		4.6	3.6	4.8
Accounts receivable:
Other		5.7	6.6	5.4
Allowance for credit losses		(5.7)	(5.7)	(5.5)
Delayed customer billings		4.6	3.6	4.8
Inventories:
Natural gas		40.7	52.4	66.1
Materials and supplies		18.9	19.1	17.2
Regulatory assets		31	41.6	67.3
Prepayments		6.8	6.4	4.1
Total Current Assets		175.8	168.6	260.4
Deferred Charges and Other Assets:
Regulatory assets		612.6	606.9	560.4
Other		84.2	84.2	81.7
Total Deferred Charges and Other Assets		696.8	691.1	649.9
Total Assets		2,463.3	2,449.3	2,469.6
Deferred income taxes		0	0	7.8
Capitalization:
Retained earnings		639.2	642.1	595.3
Total Shareholders' Equity		924.1	928	900.7
Long-term debt (less current portion)		746	745.9	745.6
Total Capitalization		1,670.1	1,673.9	1,646.3
Paid-in capital and common stock		284.9	285.9	305.4
Current Liabilities:
Advance customer billings		8.8	8.1	9.7
Wages and compensation accrued		3.6	6.6	3.2
Customer deposits		20	19.3	19.7
Taxes accrued		32.6	34.5	28.8
Other current liabilities		18.2	14.7	20.7
Total Current Liabilities		249.9	240.3	319
Deferred Credits and Other Liabilities:
Deferred income taxes		13	9.1	0
Pension and postretirement benefit costs		26.5	27.2	51.4
Asset retirement obligations		455.8	451	402.8
Regulatory liabilities		20.7	21.2	22.2
Other noncurrent liabilities		27.3	26.6	27.9
Total Deferred Credits and Other Liabilities		543.3	535.1	504.3
Commitments and Contingencies (Note 11)
Total Capitalization and Liabilities		2,463.3	2,449.3	2,469.6
Spire Alabama Inc [Member] | Nonrelated Party [Member]
Current Assets:
Utility		73.7	42.2	100.2
Accounts receivable:
Utility		73.7	42.2	100.2
Current Liabilities:
Accounts payable		33.7	28.4	87.1
Spire Alabama Inc [Member] | Related Party [Member]
Current Assets:
Utility		0.1	1.2	0.8
Accounts receivable:
Utility		0.1	1.2	0.8
Current Liabilities:
Notes payable		128.5	124.1	145.8
Accounts payable		$ 4.5	$ 4.6	$ 4
[1]Accumulated other comprehensive income (loss)

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Non-utility property, accumulated depreciation and amortization	$ 76.5	$ 71.1	$ 55.6
Preferred stock, par value (in dollars per share)	$ 25	$ 25	$ 25
Common stock, par value (in dollars per share)	$ 1	$ 1	$ 1
Common stock, shares authorized (in shares)	70,000,000	70,000,000	70,000,000
Common stock, shares issued (in shares)	55,000,000	53,200,000	52,500,000
Common Stock, shares outstanding (in shares)	55,000,000	53,200,000	52,500,000
Depositary Shares [Member]
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	10,000,000	10,000,000	10,000,000
Preferred stock, shares outstanding (in shares)	10,000,000	10,000,000	10,000,000
Spire Missouri [Member]
Common stock, par value (in dollars per share)	$ 1	$ 1	$ 1
Common stock, shares authorized (in shares)	50,000,000	50,000,000	50,000,000
Common stock, shares issued (in shares)	25,855	25,855	25,325
Common Stock, shares outstanding (in shares)	25,855	25,855	25,325
Spire Alabama Inc [Member]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	3,000,000	3,000,000	3,000,000
Common stock, shares issued (in shares)	2,000,000	2,000,000	2,000,000
Common Stock, shares outstanding (in shares)	2,000,000	2,000,000	2,000,000

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Millions	Common Stock [Member] Spire Missouri [Member]	Common Stock [Member] Spire Alabama Inc [Member]	Common Stock [Member]	Preferred Stock [Member]	Additional Paid-in Capital [Member] Spire Missouri [Member]	Additional Paid-in Capital [Member] Spire Alabama Inc [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member] Spire Missouri [Member]	Retained Earnings [Member] Spire Alabama Inc [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member] Spire Missouri [Member]	AOCI Attributable to Parent [Member]		Spire Missouri [Member]		Spire Alabama Inc [Member]	Total
Balance (in shares) at Sep. 30, 2022	25,325	1,972,052	52,494,543
Balance at Sep. 30, 2022	$ 0.1	$ 0	$ 52.5	$ 242	$ 816.1	$ 316.9	$ 1,571.3	$ 931.9	$ 589.1	$ 905.5	$ (2.7)	$ 47.2	[1]	$ 1,745.4	[1]	$ 906	$ 2,818.5
Net Income	0	0	$ 0		0	0	0	47.3	9.2	91	0	0	[1]	47.3		9.2	91
Dividend reinvestment plan (in shares)			5,700
Dividend reinvestment plan			$ 0	0			0.4			0		0	[1]				0.4
Stock-based compensation costs			$ 0				1.4			0		0	[1]				1.4
Stock activity under stock-based compensation plans (in shares)			58,678
Stock activity under stock-based compensation plans			$ 0	0			0			0		0					0
Employees’ tax withholding for stock-based compensation (in shares)			(17,225)
Employees’ tax withholding for stock-based compensation			$ 0	0			(1.3)			0		0	[1]				(1.3)
Temporary equity adjustment to redemption value			0				0			(1.7)		0	[1]				(1.7)
Common stock, dividends		0	0			0	0		(3)	(38.1)		0	[1]			(3)	(38.1)
Preferred stock dividends			0				0			(3.7)		0	[1]				(3.7)
Other Comprehensive Income, Net of Tax	$ 0		$ 0	0	0		0	0		0	0.1	(2.4)		0.1	[1]		(2.4)
Return of capital to Spire		$ 0				(11.5)			0							(11.5)
Balance (in shares) at Dec. 31, 2022	25,325	1,972,052	52,541,696
Balance at Dec. 31, 2022	$ 0.1	$ 0	$ 52.5	242	816.1	305.4	1,571.8	979.2	595.3	953	(2.6)	44.8	[1]	1,792.8	[1]	900.7	2,864.1
Balance (in shares) at Sep. 30, 2023	25,855	1,972,052	53,170,224
Balance at Sep. 30, 2023	$ 0.1	$ 0	$ 53.2	242	854.8	285.9	1,616.5	992.4	642.1	958	(2.5)	47.6	[1]	1,844.8	[1]	928	2,917.3
Net Income	0	0	$ 0		0	0	0	57	11.1	85.1	0	0	[1]	57	[1]	11.1	85.1
Common stock issued (in shares)			1,744,549
Common stock issued			$ 1.7	0			111.1			0		0					112.8
Dividend reinvestment plan (in shares)			6,774
Dividend reinvestment plan			$ 0	0			0.4			0		0	[1]				0.4
Stock-based compensation costs			$ 0				0.9			0		0	[1]				0.9
Stock activity under stock-based compensation plans (in shares)			75,706
Stock activity under stock-based compensation plans			$ 0.1	0			(0.1)			0		0					0
Employees’ tax withholding for stock-based compensation (in shares)			(23,559)
Employees’ tax withholding for stock-based compensation			$ 0	0			(1.4)			0		0	[1]				(1.4)
Temporary equity adjustment to redemption value			0				0			(1.9)		0	[1]				(1.9)
Common stock, dividends		0	0			0	0		(14)	(40.2)		0	[1]			(14)	(40.2)
Preferred stock dividends			0				0			(3.7)		0	[1]				(3.7)
Other Comprehensive Income, Net of Tax	$ 0		$ 0	0	0		0	0		0	0.1	(18.5)		0.1	[1]		(18.5)
Return of capital to Spire		$ 0				(1)			0							(1)
Balance (in shares) at Dec. 31, 2023	25,855	1,972,052	54,973,694
Balance at Dec. 31, 2023	$ 0.1	$ 0	$ 55	$ 242	$ 854.8	$ 284.9	$ 1,727.4	$ 1,049.4	$ 639.2	$ 997.3	$ (2.4)	$ 29.1	[1]	$ 1,901.9	[1]	$ 924.1	$ 3,050.8
[1]Accumulated other comprehensive income (loss)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Shareholders' Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Common stock, dividends per share declared (in dollars per share)	$ 0.755	$ 0.72
Preferred stock dividends per share declared (in dollars per share)	$ 0.36875	$ 0.36875

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023		Dec. 31, 2022
Operating Activities:
Net Income	$ 85.1		$ 91
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	67		62.1
Deferred income taxes and investment tax credits	21		21.6
Changes in assets and liabilities:
Accounts receivable	(255.5)		(156.9)
Inventories	2.9		49.7
Regulatory assets and liabilities	91.7		(90.1)
Accounts payable	54		(96.7)
Delayed/advance customer billings, net	4		(7.2)
Taxes accrued	(42.3)		(32.1)
Other assets and liabilities	40.9		(15.6)
Other	1.2		3.4
Net cash provided by (used in) operating activities	70		(170.8)
Delayed/advance customer billings	4		(7.2)
Investing Activities:
Capital expenditures	(226.5)		(154.8)
Other	1.3		3.1
Net cash used in investing activities	(225.2)		(151.7)
Financing Activities:
Issuance of long-term debt	0		205
Repayment of long-term debt	(6.6)		(31.2)
Issuance of short-term debt, net	92		189.5
Issuance of common stock	113.2		0.4
Dividends paid on common stock	(38.8)		(36.3)
Dividends paid on preferred stock	(3.7)		(3.7)
Other financing activities	(1.4)		(2.7)
Net cash provided by financing activities	154.7		321
Net Decrease in Cash, Cash Equivalents, and Restricted Cash	(0.5)		(1.5)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	25.8		20.5
Cash, Cash Equivalents, and Restricted Cash at End of Period	25.3		19
Supplemental disclosure of cash paid for:
Interest, net of amounts capitalized	(44.3)		(36.9)
Income taxes	(0.3)		(0.3)
Spire Missouri [Member]
Operating Activities:
Net Income	57	[1]	47.3
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	42.1		38.6
Deferred income taxes and investment tax credits	9.6		8.1
Changes in assets and liabilities:
Accounts receivable	(190.9)		(208.5)
Inventories	(9.4)		24.4
Regulatory assets and liabilities	81.6		(61.5)
Accounts payable	34.6		66.4
Delayed/advance customer billings, net	4.4		(7.1)
Taxes accrued	(33.9)		(26.2)
Other assets and liabilities	54.1		13.2
Other	0.5		0.4
Net cash provided by (used in) operating activities	49.7		(104.9)
Delayed/advance customer billings	4.4		(7.1)
Investing Activities:
Capital expenditures	(144.7)		(102)
Other	1.5		1
Net cash used in investing activities	(143.2)		(101)
Financing Activities:
Net cash provided by financing activities	92.7		205.9
Net Decrease in Cash, Cash Equivalents, and Restricted Cash	(0.8)		0
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	0.8		0
Cash, Cash Equivalents, and Restricted Cash at End of Period	0		0
Borrowings from Spire, net	92.7		205.9
Borrowings from (Repayments to) Spire, net	92.7		205.9
Supplemental disclosure of cash paid for:
Interest, net of amounts capitalized	(25.7)		(21)
Income taxes	0		0
Spire Alabama Inc [Member]
Operating Activities:
Net Income	11.1		9.2
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	17.9		17
Deferred income taxes and investment tax credits	3.9		3.2
Changes in assets and liabilities:
Accounts receivable	(29.4)		(29.5)
Inventories	12		5.6
Regulatory assets and liabilities	8.5		(29.7)
Accounts payable	7.4		10.9
Delayed/advance customer billings, net	(0.3)		(0.1)
Taxes accrued	(2)		(2.5)
Other assets and liabilities	2.1		15.1
Other	0.1		0.1
Net cash provided by (used in) operating activities	31.3		(0.7)
Delayed/advance customer billings	(0.3)		(0.1)
Investing Activities:
Capital expenditures	(22.3)		(38.2)
Other	0.3		0.1
Net cash used in investing activities	(22)		(38.1)
Financing Activities:
Issuance of long-term debt	0		175
Dividends paid on common stock	(14)		(11)
Other financing activities	0		(1)
Net cash provided by financing activities	(10.5)		36.4
Net Decrease in Cash, Cash Equivalents, and Restricted Cash	(1.2)		(2.4)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	1.2		2.4
Cash, Cash Equivalents, and Restricted Cash at End of Period	0		0
Borrowings from Spire, net	4.5		(115.1)
Borrowings from (Repayments to) Spire, net	4.5		(115.1)
Return of capital to Spire	(1)		(11.5)
Supplemental disclosure of cash paid for:
Interest, net of amounts capitalized	(10.9)		(5.8)
Income taxes	$ 0		$ 0
[1]Accumulated other comprehensive income (loss)

Note 1 - Summary of Significant

Note 1 - Summary of Significant Accounting Policies	3 Months Ended
	Dec. 31, 2023
Notes to Financial Statements
Significant Accounting Policies [Text Block]	1. BASIS OF PRESENTATION The accompanying unaudited financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) for interim financial information with the instructions to Form 10 10 01 not 10 10 September 30, 2023 The consolidated financial position, results of operations, and cash flows of Spire include the accounts of the Company and all its subsidiaries. Transactions and balances between consolidated entities have been eliminated from the consolidated financial statements of Spire. In compliance with GAAP, transactions between Spire Missouri and Spire Alabama and their affiliates, as well as intercompany balances on their balance sheets, have not NATURE OF OPERATIONS Note 10 The Company’s earnings are derived primarily from its Gas Utility segment. Due to the seasonal nature of the Utilities’ business and the volumetric Spire Missouri rate design, earnings are typically concentrated during the heating season of November April not REGULATED OPERATIONS 980, Regulated Operations third may As authorized by the Missouri Public Service Commission (MoPSC), the Mississippi Public Service Commission (MSPSC) and the Alabama Public Service Commission (APSC), the Purchased Gas Adjustment (PGA) clauses and Gas Supply Adjustment (GSA) riders allow the Utilities to pass through to customers the cost of purchased gas supplies. Regulatory assets and liabilities related to the PGA clauses and the GSA riders are both labeled Unamortized Purchased Gas Adjustments herein. See additional information about regulatory assets and liabilities in Note 5 DERIVATIVES 815, Derivatives and Hedging not first 2024, not December 31, 2023. TRANSACTIONS WITH AFFILIATES Three Months Ended December 31, 2023 2022 Spire Missouri Purchases of natural gas from Spire Marketing $ 5.0 $ 28.5 Transportation services received from Spire STL Pipeline 8.2 8.1 Natural gas storage services from Spire Storage Salt Plains LLC 0.3 — Spire Alabama Purchases of natural gas from Spire Marketing $ 3.4 $ 1.1 RESTRICTED CASH AND OTHER INVESTMENTS December 31, 2023 December 31, 2023 September 30, 2023 December 31, 2022 BUSINESS COMBINATIONS January 20, 2024. ACCRUED CAPITAL EXPENDITURES December 31, September 30, December 31, 2023 2023 2022 Spire $ 90.5 $ 104.3 $ 63.1 Spire Missouri 38.1 56.5 32.8 Spire Alabama 2.4 4.6 9.4 ACCOUNTS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES not Spire Spire Missouri Spire Alabama Three Months Ended December 31, 2023 2022 2023 2022 2023 2022 Allowance at beginning of period $ 32.5 $ 31.9 $ 26.2 $ 24.9 $ 5.7 $ 6.3 Provision for expected credit losses 4.1 4.1 3.6 3.8 0.3 0.2 Write-offs, net of recoveries (1.2 ) (1.5 ) (0.9 ) (0.5 ) (0.3 ) (1.0 ) Allowance at end of period $ 35.4 $ 34.5 $ 28.9 $ 28.2 $ 5.7 $ 5.5

Note 2 - Revenue

Note 2 - Revenue	3 Months Ended
	Dec. 31, 2023
Notes to Financial Statements
Revenue from Contract with Customer [Text Block]	2. The following tables show revenue disaggregated by source and customer type. Three Months Ended December 31, 2023 2022 Spire Gas Utility: Residential $ 492.8 $ 518.0 Commercial and industrial 157.9 170.6 Transportation 32.6 30.9 Off-system and other incentive 6.4 7.6 Other customer revenue 5.5 4.4 Total revenue from contracts with customers 695.2 731.5 Changes in accrued revenue under alternative revenue programs 20.0 1.5 Total Gas Utility operating revenues 715.2 733.0 Gas Marketing 36.3 74.1 Midstream 14.9 15.2 Other 4.1 4.0 Total before eliminations 770.5 826.3 Intersegment eliminations (see Note 10, Information by Operating Segment) (13.9 ) (12.3 ) Total Operating Revenues $ 756.6 $ 814.0 Spire Missouri Residential $ 388.8 $ 400.6 Commercial and industrial 110.2 122.9 Transportation 9.0 9.1 Off-system and other incentive 4.1 5.1 Other customer revenue 2.5 2.0 Total revenue from contracts with customers 514.6 539.7 Changes in accrued revenue under alternative revenue programs 20.8 1.5 Total Operating Revenues $ 535.4 $ 541.2 Spire Alabama Residential $ 84.4 $ 96.3 Commercial and industrial 34.7 33.6 Transportation 20.8 19.3 Off-system and other incentive 2.3 2.4 Other customer revenue 0.9 1.2 Total revenue from contracts with customers 143.1 152.8 Changes in accrued revenue under alternative revenue programs (1.0 ) (0.4 ) Total Operating Revenues $ 142.1 $ 152.4 Gross receipts taxes associated with the Company’s natural gas utility services are imposed on the Company, Spire Missouri, and Spire Alabama and billed to its customers. The expense amounts (shown in the table below) are reported gross in the “Taxes, other than income taxes” line in the statements of income, and corresponding revenues are reported in “Operating Revenues.” Three Months Ended December 31, 2023 2022 Spire $ 31.1 $ 30.4 Spire Missouri 22.5 22.1 Spire Alabama 6.9 6.8

Note 3 - Earnings Per Common Sh

Note 3 - Earnings Per Common Share	3 Months Ended
	Dec. 31, 2023
Notes to Financial Statements
Earnings Per Share [Text Block]	3. Three Months Ended December 31, 2023 2022 Basic Earnings Per Common Share: Net Income $ 85.1 $ 91.0 Less: Provision for preferred dividends 3.7 3.7 Income allocated to participating securities 0.1 0.1 Income Available to Common Shareholders $ 81.3 $ 87.2 Weighted Average Common Shares Outstanding (in millions) 53.5 52.4 Basic Earnings Per Common Share $ 1.52 $ 1.66 Diluted Earnings Per Common Share: Net Income $ 85.1 $ 91.0 Less: Provision for preferred dividends 3.7 3.7 Income allocated to participating securities 0.1 0.1 Income Available to Common Shareholders $ 81.3 $ 87.2 Weighted Average Common Shares Outstanding (in millions) 53.5 52.4 Dilutive Effect of forward sales of common stock, restricted stock and restricted stock units (in millions)* 0.1 0.2 Weighted Average Diluted Common Shares (in millions) 53.6 52.6 Diluted Earnings Per Common Share $ 1.52 $ 1.66 * Calculation excludes certain outstanding or potential common shares (shown in millions by period at the right) attributable to (1) stock units subject to performance or market conditions and (2) restricted stock, which could have a dilutive effect in the future 0.2 0.2

Note 4 - Shareholders' Equity

Note 4 - Shareholders' Equity	3 Months Ended
	Dec. 31, 2023
Notes to Financial Statements
Equity [Text Block]	4. EQUITY ATM Program Under Spire’s “at-the-market” (ATM) equity distribution agreement and as authorized by its board of directors, the Company may may first 2024, December 11, 2023, January 25, 2024, January 2027.

Note 5 - Regulatory Matters

Note 5 - Regulatory Matters	3 Months Ended
	Dec. 31, 2023
Notes to Financial Statements
Public Utilities Disclosure [Text Block]	5. As explained in Note 1 980, Regulated Operations December 31, 2023 September 30, 2023 December 31, 2022 December 31, September 30, December 31, Spire 2023 2023 2022 Regulatory Assets: Current: Unamortized purchased gas adjustments $ 207.0 $ 293.2 $ 238.9 Other 49.4 55.1 30.2 Total Current Regulatory Assets 256.4 348.3 269.1 Noncurrent: Pension and postretirement benefit costs 255.3 261.0 277.3 Cost of removal 640.8 633.2 506.1 Future income taxes due from customers 145.6 144.5 138.6 Energy efficiency 57.5 56.3 59.1 Unamortized purchased gas adjustments 20.3 23.0 107.9 Other 147.4 131.2 131.7 Total Noncurrent Regulatory Assets 1,266.9 1,249.2 1,220.7 Total Regulatory Assets $ 1,523.3 $ 1,597.5 $ 1,489.8 Regulatory Liabilities: Current: Other $ 7.1 $ 7.3 $ 3.7 Total Current Regulatory Liabilities 7.1 7.3 3.7 Noncurrent: Deferred taxes due to customers 124.5 128.0 140.9 Pension and postretirement benefit costs 188.2 185.2 156.6 Accrued cost of removal 130.3 126.6 33.7 Unamortized purchased gas adjustments 23.7 11.2 — Other 20.5 21.4 13.7 Total Noncurrent Regulatory Liabilities 487.2 472.4 344.9 Total Regulatory Liabilities $ 494.3 $ 479.7 $ 348.6 December 31, September 30, December 31, Spire Missouri 2023 2023 2022 Regulatory Assets: Current: Unamortized purchased gas adjustments $ 194.1 $ 269.4 $ 181.2 Other 18.8 23.7 10.0 Total Current Regulatory Assets 212.9 293.1 191.2 Noncurrent: Future income taxes due from customers 137.3 136.2 130.1 Pension and postretirement benefit costs 185.5 189.1 197.4 Energy efficiency 57.5 56.3 59.1 Unamortized purchased gas adjustments 20.3 23.0 107.9 Cost of removal 97.0 97.0 23.9 Other 133.2 116.0 116.3 Total Noncurrent Regulatory Assets 630.8 617.6 634.7 Total Regulatory Assets $ 843.7 $ 910.7 $ 825.9 Regulatory Liabilities: Noncurrent: Deferred taxes due to customers $ 111.6 $ 114.8 $ 124.6 Pension and postretirement benefit costs 160.2 156.5 127.4 Accrued cost of removal 93.4 90.4 — Unamortized purchased gas adjustments 23.7 11.2 — Other 15.6 16.5 7.0 Total Noncurrent Regulatory Liabilities 404.5 389.4 259.0 Total Regulatory Liabilities $ 404.5 $ 389.4 $ 259.0 December 31, September 30, December 31, Spire Alabama 2023 2023 2022 Regulatory Assets: Current: Unamortized purchased gas adjustments $ 12.2 $ 21.7 $ 54.5 Other 18.8 19.9 12.8 Total Current Regulatory Assets 31.0 41.6 67.3 Noncurrent: Future income taxes due from customers 1.9 2.0 2.1 Pension and postretirement benefit costs 66.0 67.8 75.1 Cost of removal 543.7 536.2 482.2 Other 1.0 0.9 1.0 Total Noncurrent Regulatory Assets 612.6 606.9 560.4 Total Regulatory Assets $ 643.6 $ 648.5 $ 627.7 Regulatory Liabilities: Noncurrent: Pension and postretirement benefit costs $ 17.3 $ 17.9 $ 18.7 Other 3.4 3.3 3.5 Total Noncurrent Regulatory Liabilities 20.7 21.2 22.2 Total Regulatory Liabilities $ 20.7 $ 21.2 $ 22.2 A portion of the Company’s and Spire Missouri’s regulatory assets are not December 31, September 30, December 31, 2023 2023 2022 Spire Pension and postretirement benefit costs $ 134.0 $ 133.4 $ 127.0 Future income taxes due from customers 143.6 142.5 136.4 Unamortized purchased gas adjustments 214.4 292.4 289.1 Other 117.0 104.2 122.9 Total Regulatory Assets Not Earning a Return $ 609.0 $ 672.5 $ 675.4 Spire Missouri Pension and postretirement benefit costs $ 134.0 $ 133.4 $ 127.0 Future income taxes due from customers 137.3 136.2 130.1 Unamortized purchased gas adjustments 214.4 292.4 289.1 Other 117.0 104.2 122.9 Total Regulatory Assets Not Earning a Return $ 602.7 $ 666.2 $ 669.1 Like all the Company’s regulatory assets, these regulatory assets as of December 31, 2023 two not not 35 not not Spire Missouri In 2022, 2022 0135 2022 0136 2020 2021 February 2021 ( December 15, 2022, January 19, 2023, no July 12, 2023, May 2024. November 2, 2023, The Infrastructure System Replacement Surcharge (ISRS) allows Spire Missouri expedited recovery for its investment to replace qualifying components of its infrastructure without the necessity of a formal rate case. All prior ISRS revenues were reset to zero December 26, 2022 April 20, 2023, May 6, 2023, October 2022 February 2023. October 4, 2023, October 23, 2023, March 2023 August 2023. January 17, 2024, September 2023 February 2024. July 2024. In fiscal 2023, November 2022 January 2023. 2024, November 2023. 2024. Spire Alabama In the first 2023, September 30, 2023, January 1, 2023. October 26, 2023, September 30, 2024. December 27, 2023, January 1, 2024. Spire Alabama’s rate schedules for natural gas distribution charges contain a GSA rider which permits the pass-through to customers of changes in the cost of gas supply. In fiscal 2023, December 1, 2022 January 1, 2023, 2024, October 1, 2023 January 1, 2024, Spire In addition to those discussed above for Spire Missouri and Spire Alabama, Spire is affected by the following regulatory matters. On October 26, 2022, 2023 December 21, 2022 January 1, 2023. April 30, 2023 July 1, 2023. September 30, 2023 December 13, 2023. October 26, 2023, 2024 December 12, 2023 December 13, 2023. On September 14, 2022, June 30, 2022, December 6, 2022, January 1, 2023. September 1, 2023, June 30, 2023, December 14, 2023, January 1, 2024.

Note 6 - Financing

Note 6 - Financing	3 Months Ended
	Dec. 31, 2023
Notes to Financial Statements
Debt Disclosure [Text Block]	6. Short-term Spire, Spire Missouri and Spire Alabama have a syndicated revolving credit facility pursuant to a loan agreement with 12 July 22, 2027. may three may no December 31, 2023 December 31, 2023 Spire has a commercial paper program (“CP Program”) pursuant to which it may may not may 365 After quarter end, on January 3, 2024, October 3, 2024. one Information about short-term borrowings, including Spire Missouri’s and Spire Alabama’s borrowings from Spire, is presented in the following table. As of December 31, 2023 Spire (Parent Only) Spire Missouri Spire Alabama Spire CP Term Spire Spire Consol- Program Loan Note Note idated Three Months Ended December 31, 2023 Highest borrowings outstanding $ 1,135.0 $ — $ 643.6 $ 132.5 $ 1,135.0 Lowest borrowings outstanding 955.5 — 526.5 107.9 955.5 Weighted average borrowings 1,043.5 — 583.3 119.8 1,043.5 Weighted average interest rate 5.7 % n/a 5.7 % 5.7 % 5.7 % As of December 31, 2023 Borrowings outstanding $ 1,047.5 $ — $ 633.3 $ 128.5 $ 1,047.5 Weighted average interest rate 5.7 % n/a 5.7 % 5.7 % 5.7 % As of September 30, 2023 Borrowings outstanding $ 955.5 $ — $ 540.6 $ 124.1 $ 955.5 Weighted average interest rate 5.6 % n/a 5.6 % 5.6 % 5.6 % As of December 31, 2022 Borrowings outstanding $ 1,227.0 $ — $ 651.2 $ 145.8 $ 1,227.0 Weighted average interest rate 4.9 % n/a 4.9 % 4.9 % 4.9 % Long-term The long-term debt agreements of Spire, Spire Missouri and Spire Alabama contain customary financial covenants and default provisions. As of December 31, 2023 no Interest expense shown on the statements of income is net of the capitalized interest amounts shown in the following table. Three Months Ended December 31, 2023 2022 Spire $ 3.8 $ 1.6 Spire Missouri 1.2 0.5 Spire Alabama 0.4 0.7

Note 7 - Fair Value of Financia

Note 7 - Fair Value of Financial Instruments	3 Months Ended
	Dec. 31, 2023
Notes to Financial Statements
Fair Value Disclosures [Text Block]	7. The carrying amounts of cash and cash equivalents, notes receivable, and short-term debt approximate fair value due to the short maturity of these instruments. The fair values of long-term debt are estimated based on market prices for similar issues. Refer to Note 8 The carrying amounts and estimated fair values of financial instruments not no 3 December 31, 2023 September 30, 2023 December 31, 2022 Classification of Estimated Fair Value Carrying Amount Fair Value Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Spire As of December 31, 2023 Cash and cash equivalents $ 4.8 $ 4.8 $ 4.8 $ — Notes payable 1,047.5 1,047.5 — 1,047.5 Long-term debt, including current portion 3,704.8 3,481.5 — 3,481.5 As of September 30, 2023 Cash and cash equivalents $ 5.6 $ 5.6 $ 5.6 $ — Notes payable 955.5 955.5 — 955.5 Long-term debt, including current portion 3,710.6 3,270.2 — 3,270.2 As of December 31, 2022 Cash and cash equivalents $ 4.8 $ 4.8 $ 4.8 $ — Notes payable 1,227.0 1,227.0 — 1,227.0 Long-term debt, including current portion 3,412.9 3,083.7 — 3,083.7 Spire Missouri As of December 31, 2023 Notes payable – associated companies $ 633.3 $ 633.3 $ — $ 633.3 Long-term debt, including current portion 1,785.8 1,689.5 — 1,689.5 As of September 30, 2023 Cash and cash equivalents $ 0.8 $ 0.8 $ 0.8 $ — Notes payable – associated companies 540.6 540.6 — 540.6 Long-term debt 1,785.4 1,592.4 — 1,592.4 As of December 31, 2022 Notes payable – associated companies $ 651.2 $ 651.2 $ — $ 651.2 Long-term debt, including current portion 1,638.1 1,497.7 — 1,497.7 Spire Alabama As of December 31, 2023 Notes payable – associated companies $ 128.5 $ 128.5 $ — $ 128.5 Long-term debt 746.0 701.7 — 701.7 As of September 30, 2023 Cash and cash equivalents $ 1.2 $ 1.2 $ 1.2 $ — Notes payable – associated companies 124.1 124.1 — 124.1 Long-term debt 745.9 648.0 — 648.0 As of December 31, 2022 Notes payable – associated companies $ 145.8 $ 145.8 $ — $ 145.8 Long-term debt 745.6 674.5 — 674.5

Note 8 - Fair Value Measurement

Note 8 - Fair Value Measurements	3 Months Ended
	Dec. 31, 2023
Notes to Financial Statements
Fair Value Measurement and Measurement Inputs, Recurring and Nonrecurring [Text Block]	8. The information presented in the following tables categorizes the assets and liabilities in the balance sheets that are accounted for at fair value on a recurring basis in periods subsequent to initial recognition. The mutual funds included in Level 1 Derivative instruments included in Level 1 2 2 3 no 3 December 31, 2023 September 30, 2023 December 31, 2022 The mutual funds are included in “Other Investments” on the Company’s balance sheets and in “Other Property and Investments” on Spire Missouri’s balance sheets. Changes in their recurring valuations are recorded as unrealized gains or losses in the corresponding income statement. Derivative assets and liabilities, including receivables and payables associated with cash margin requirements, are presented net in the balance sheets when a legally enforceable netting agreement exists between the Company, Spire Missouri, or Spire Alabama and the counterparty to a derivative contract. Spire Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Effects of Netting and Cash Margin Receivables /Payables Total As of December 31, 2023 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 22.0 $ — $ — $ 22.0 NYMEX/ICE natural gas contracts 4.7 — (4.7 ) — Gas Marketing: NYMEX/ICE natural gas contracts 13.2 — (13.2 ) — Natural gas commodity contracts — 45.5 (1.4 ) 44.1 Other: U.S. stock/bond mutual funds 14.6 — — 14.6 U.S. bonds 21.6 — — 21.6 Global bonds 1.4 — — 1.4 Interest rate swaps — 22.7 — 22.7 Total $ 77.5 $ 68.2 $ (19.3 ) $ 126.4 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 60.7 $ — $ (60.7 ) $ — Gasoline and heating oil contracts — 0.4 (0.4 ) — Gas Marketing: NYMEX/ICE natural gas contracts 32.7 — (32.7 ) — Natural gas commodity contracts — 24.5 (1.4 ) 23.1 Other: Interest rate swaps — 2.0 — 2.0 Total $ 93.4 $ 26.9 $ (95.2 ) $ 25.1 Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Effects of Netting and Cash Margin Receivables /Payables Total As of September 30, 2023 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 20.4 $ — $ — $ 20.4 NYMEX/ICE natural gas contracts 6.3 — (6.3 ) — Gasoline and heating oil contracts — 0.1 (0.1 ) — Gas Marketing: NYMEX/ICE natural gas contracts 10.1 — (10.1 ) — Natural gas commodity contracts — 36.7 (3.6 ) 33.1 Other: U.S. stock/bond mutual funds 37.6 — — 37.6 Interest rate swaps — 44.2 — 44.2 Total $ 74.4 $ 81.0 $ (20.1 ) $ 135.3 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 50.8 $ — $ (44.0 ) $ 6.8 Gas Marketing: NYMEX/ICE natural gas contracts 21.8 — (21.8 ) — Natural gas commodity contracts — 27.6 (3.6 ) 24.0 Total $ 72.6 $ 27.6 $ (69.4 ) $ 30.8 As of December 31, 2022 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 19.5 $ — $ — $ 19.5 NYMEX/ICE natural gas contracts 0.4 — (0.4 ) — Gasoline and heating oil contracts 0.2 — (0.2 ) — Gas Marketing: NYMEX/ICE natural gas contracts 52.0 — (52.0 ) — Natural gas commodity contracts * — 92.9 (13.2 ) 79.7 Other: U.S. stock/bond mutual funds 28.3 — — 28.3 Interest rate swaps * — 61.4 — 61.4 Total $ 100.4 $ 154.3 $ (65.8 ) $ 188.9 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 35.7 $ — $ (35.7 ) $ — Gasoline and heating oil contracts 0.2 — (0.2 ) — Gas Marketing: NYMEX/ICE natural gas contracts 58.4 — (58.4 ) — Natural gas commodity contracts * — 71.1 (13.2 ) 57.9 Other: Interest rate swaps * — 0.8 — 0.8 Total $ 94.3 $ 71.9 $ (107.5 ) $ 58.7 * Subsequent to the issuance of its consolidated financial statements for the quarter ended December 31, 2022, fourth 2023, 2 1 December 31, 2022. not Spire Missouri Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Effects of Netting and Cash Margin Receivables /Payables Total As of December 31, 2023 ASSETS U.S. stock/bond mutual funds $ 22.0 $ — $ — $ 22.0 NYMEX/ICE natural gas contracts 4.7 — (4.7 ) — Total $ 26.7 $ — $ (4.7 ) $ 22.0 LIABILITIES NYMEX/ICE natural gas contracts $ 60.7 $ — $ (60.7 ) $ — Gasoline and heating oil contracts — 0.4 (0.4 ) — Total $ 60.7 $ 0.4 $ (61.1 ) $ — As of September 30, 2023 ASSETS U.S. stock/bond mutual funds $ 20.4 $ — $ — $ 20.4 NYMEX/ICE natural gas contracts 6.3 — (6.3 ) — Gasoline and heating oil contracts — 0.1 (0.1 ) — Total $ 26.7 $ 0.1 $ (6.4 ) $ 20.4 LIABILITIES NYMEX/ICE natural gas contracts $ 50.8 $ — $ (44.0 ) $ 6.8 As of December 31, 2022 ASSETS U.S. stock/bond mutual funds $ 19.5 $ — $ — $ 19.5 NYMEX/ICE natural gas contracts 0.4 — (0.4 ) — Gasoline and heating oil contracts 0.2 — (0.2 ) — Total $ 20.1 $ — $ (0.6 ) $ 19.5 LIABILITIES NYMEX/ICE natural gas contracts $ 35.7 $ — $ (35.7 ) $ — Gasoline and heating oil contracts 0.2 — (0.2 ) — Total $ 35.9 $ — $ (35.9 ) $ —

Note 9 - Pension Plans and Othe

Note 9 - Pension Plans and Other Postretirement Benefits	3 Months Ended
	Dec. 31, 2023
Notes to Financial Statements
Retirement Benefits [Text Block]	9. Pension Plans Spire and the Utilities maintain pension plans for their employees. Spire Missouri and Spire Alabama have non-contributory, defined benefit, trusteed forms of pension plans covering the majority of their employees. Qualified plan assets are comprised of mutual and commingled funds consisting of U.S. equities with varying strategies, global equities, alternative investments, and fixed income investments. The net periodic pension cost includes components shown in the following tables. The components other than the service costs and regulatory adjustment are presented in “Other Income, Net” in the income statement, except for Spire Alabama’s losses on lump-sum settlements. Such losses are capitalized in regulatory balances and amortized over the remaining actuarial life of individuals in the plan, and that amortization is presented in “Other Income, Net.” Three Months Ended December 31, 2023 2022 Spire Service cost – benefits earned during the period $ 4.0 $ 4.1 Interest cost on projected benefit obligation 6.8 6.4 Expected return on plan assets (6.3 ) (6.4 ) Amortization of prior service credit (1.1 ) (1.1 ) Amortization of actuarial loss 1.6 1.6 Loss on lump-sum settlements — 8.6 Subtotal 5.0 13.2 Regulatory adjustment 8.7 1.8 Net pension cost $ 13.7 $ 15.0 Spire Missouri Service cost – benefits earned during the period $ 2.6 $ 2.8 Interest cost on projected benefit obligation 4.8 4.5 Expected return on plan assets (4.3 ) (4.5 ) Amortization of prior service credit (0.5 ) (0.5 ) Amortization of actuarial loss 1.5 1.5 Subtotal 4.1 3.8 Regulatory adjustment 6.3 8.1 Net pension cost $ 10.4 $ 11.9 Spire Alabama Service cost – benefits earned during the period $ 1.2 $ 1.1 Interest cost on projected benefit obligation 1.3 1.3 Expected return on plan assets (1.2 ) (1.1 ) Amortization of prior service credit (0.6 ) (0.6 ) Amortization of actuarial loss 0.2 0.1 Loss on lump-sum settlements — 8.6 Subtotal 0.9 9.4 Regulatory adjustment 2.2 (6.5 ) Net pension cost $ 3.1 $ 2.9 Pursuant to the provisions of Spire Missouri’s and Spire Alabama’s pension plans, pension obligations may three December 31, 2023 For the three December 31, 2022, two one September 30, 2022. one three December 31, 2022. Effective December 23, 2021, December 26, 2022, Also effective December 23, 2021, eight eight eight eight December 26, 2022, The funding policy of the Utilities is to contribute an amount not 2024 December 31, 2023 $5.0 none 2024 December 31, 2023 $2.0. C 2024. C 2024 $14.4. Other Postretirement Benefits Spire and the Utilities provide certain life insurance benefits at retirement. Spire Missouri plans provide for medical insurance after early retirement until age 65. January 1, 2015, The net periodic postretirement benefit cost includes components shown in the following tables. The components other than the service costs and regulatory adjustment are presented in “Other Income, Net” in the income statement, except in the event Spire Alabama incurs losses on lump-sum settlements. Any such losses are capitalized in regulatory balances and amortized over the remaining actuarial life of individuals in the plan, and that amortization is presented in “Other Income, Net.” Three Months Ended December 31, 2023 2022 Spire Service cost – benefits earned during the period $ 1.1 $ 1.2 Interest cost on accumulated postretirement benefit obligation 2.1 2.1 Expected return on plan assets (4.0 ) (3.9 ) Amortization of prior service cost 0.1 0.1 Amortization of actuarial gain (1.0 ) (1.0 ) Subtotal (1.7 ) (1.5 ) Regulatory adjustment 0.2 0.1 Net postretirement benefit income $ (1.5 ) $ (1.4 ) Spire Missouri Service cost – benefits earned during the period $ 0.9 $ 1.0 Interest cost on accumulated postretirement benefit obligation 1.6 1.6 Expected return on plan assets (2.7 ) (2.6 ) Amortization of prior service cost 0.2 0.2 Amortization of actuarial gain (0.9 ) (0.8 ) Subtotal (0.9 ) (0.6 ) Regulatory adjustment 0.6 0.6 Net postretirement benefit income $ (0.3 ) $ — Spire Alabama Service cost – benefits earned during the period $ 0.2 $ 0.2 Interest cost on accumulated postretirement benefit obligation 0.5 0.4 Expected return on plan assets (1.3 ) (1.2 ) Amortization of prior service credit (0.1 ) (0.1 ) Amortization of actuarial gain — (0.1 ) Subtotal (0.7 ) (0.8 ) Regulatory adjustment (0.4 ) (0.5 ) Net postretirement benefit income $ (1.1 ) $ (1.3 ) Missouri and Alabama state laws provide for the recovery in rates of costs accrued pursuant to GAAP provided that such costs are funded through an independent, external funding mechanism. The Utilities have established Voluntary Employees’ Beneficiary Association (VEBA) and Rabbi Trusts as external funding mechanisms. The assets of the VEBA and Rabbi Trusts consist primarily of money market securities and mutual funds invested in stocks and bonds. Effective December 23, 2021, no 2022 December 2022, The Utilities’ funding policy is to contribute amounts to the trusts equal to the periodic benefit cost calculated pursuant to GAAP as recovered in rates. There have been no December 31, 2023

Note 10 - Information by Operat

Note 10 - Information by Operating Segment	3 Months Ended
	Dec. 31, 2023
Notes to Financial Statements
Segment Reporting Disclosure [Text Block]	10. The Company has three Accounting policies are described in Note 1 Management evaluates the performance of the operating segments based on the computation of net economic earnings. Net economic earnings exclude from reported net income the after-tax impacts of fair value accounting and timing adjustments associated with energy-related transactions, the impacts of acquisition, divestiture and restructuring activities, and the largely non-cash impacts of impairments and other non-recurring or unusual items such as certain regulatory, legislative, or GAAP standard-setting actions. Gas Utility Gas Marketing Midstream Other Eliminations Consolidated Three Months Ended December 31, 2023 Revenues from external customers $ 715.2 $ 36.3 $ 5.0 $ 0.1 $ — $ 756.6 Intersegment revenues — — 9.9 4.0 (13.9 ) — Total Operating Revenues 715.2 36.3 14.9 4.1 (13.9 ) 756.6 Depreciation and amortization expense 64.2 0.4 2.3 0.1 — 67.0 Interest expense 39.0 — 1.8 24.0 (14.2 ) 50.6 Income tax expense 15.7 3.8 0.6 0.9 — 21.0 Net economic earnings (loss) 75.8 7.2 2.4 (2.7 ) — 82.7 Capital expenditures 174.9 — 52.0 — (0.4 ) 226.5 Gas Utility Gas Marketing Midstream Other Eliminations Consolidated Three Months Ended December 31, 2022 Revenues from external customers $ 733.0 $ 74.1 $ 6.8 $ 0.1 $ — $ 814.0 Intersegment revenues — — 8.4 3.9 (12.3 ) — Total Operating Revenues 733.0 74.1 15.2 4.0 (12.3 ) 814.0 Depreciation and amortization expense 59.7 0.3 1.9 0.2 — 62.1 Interest expense 32.1 — 1.9 19.5 (9.9 ) 43.6 Income tax expense (benefit) 12.4 10.5 1.4 (2.7 ) — 21.6 Net economic earnings (loss) 62.9 25.7 3.8 (7.3 ) — 85.1 Capital expenditures 146.3 0.2 7.7 0.6 — 154.8 The following table reconciles the Company’s net economic earnings (loss) to net income (loss). Three Months Ended December 31, 2023 2022 Net Income $ 85.1 $ 91.0 Adjustments, pre-tax: Fair value and timing adjustments (5.2 ) (7.8 ) Acquisition activities 1.9 — Income tax adjustments 0.9 1.9 Net Economic Earnings $ 82.7 $ 85.1 The Company’s total assets by segment were as follows: December 31, September 30, December 31, 2023 2023 2022 Total Assets: Gas Utility $ 8,736.7 $ 8,486.7 $ 8,355.1 Gas Marketing 207.0 332.0 492.4 Midstream 633.9 574.3 466.6 Other 2,755.1 2,533.3 2,882.8 Eliminations (1,701.0 ) (1,612.7 ) (1,869.2 ) Total Assets $ 10,631.7 $ 10,313.6 $ 10,327.7

Note 11 - Commitments and Conti

Note 11 - Commitments and Contingencies	3 Months Ended
	Dec. 31, 2023
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	11. Commitments The Company and the Utilities have entered into contracts with various counterparties, expiring on dates through calendar 2039, December 31, 2023 November April. A consolidated subsidiary of Spire is a limited partner in Inter-Atlantic Energy Capital Ventures, L.P., an unconsolidated partnership focusing on sustainability initiatives largely tied to the natural gas utility sector. Spire committed to contribute a total of $10.0 of capital to the partnership as and when requested by the general partner. As of December 31, 2023 Contingencies The Company and the Utilities account for contingencies, including environmental liabilities, in accordance with accounting standards under the loss contingency guidance of ASC Topic 450, Contingencies In addition to matters noted below, the Company and the Utilities are involved in other litigation, claims, and investigations arising in the normal course of business. Management, after discussion with counsel, believes the final outcome will not The Company and the Utilities own and operate natural gas distribution, transmission, and storage facilities, the operations of which are subject to various environmental laws, regulations, and interpretations. While environmental issues resulting from such operations arise in the ordinary course of business, such issues have not may may may In the natural gas industry, many gas distribution companies have incurred environmental liabilities associated with sites they or their predecessor companies formerly owned or operated where manufactured gas operations took place. The Utilities each have former manufactured gas plant (MGP) operations in their respective service territories, some of which are discussed under the Spire Missouri and Spire Alabama headings below. To the extent costs are incurred associated with environmental remediation activities, the Utilities would request authority from their respective regulators to defer such costs (less any amounts received from insurance proceeds or as contributions from other potentially responsible parties (PRPs)) and collect them through future rates. To date, costs incurred for all Spire MGP sites for investigation, remediation and monitoring have not may may In 2020, March 2021, not may Spire Missouri Spire Missouri has identified three two third In conjunction with redevelopment of the Carondelet Coke site, Spire Missouri and another former owner of the site entered into an agreement (the “Remediation Agreement”) with the City development agencies, the developer, and an environmental consultant that obligates one No December 20, 2010, seven six In a letter dated June 29, 2011, second January 10, 2012, no Additionally, in correspondence dated November 30, 2016, 7 107 1980 third not March 2017 Spire Missouri has notified its insurers that it seeks reimbursement for costs incurred in the past and future potential liabilities associated with these MGP sites. While some of the insurers have denied coverage and reserved their rights, Spire Missouri retains the right to seek potential reimbursements from them. On March 10, 2015, 104 7 April 3, 2015, July 15, 2015, August 15, 2015. no In its western service area, Spire Missouri has six #1, #1, #2. 2003 September 15, 2016, six May 11, 2015, Spire Alabama Spire Alabama is in the chain of title of nine four five one In 2011, In 2012, 104 35th not 35th Assessments were performed by the EPA of the former MGP sites in Gadsden and Anniston, and NFA letters were received after each assessment. Spire In addition to those discussed above for Spire Missouri and Spire Alabama, Spire is aware of the following contingent matters. Spire Marketing, along with many natural gas industry participants, faced the unprecedented effects of Winter Storm Uri in February 2021.

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2023
Insider Trading Arr Line Items
Material Terms of Trading Arrangement [Text Block]	5. During the quarterly period ended December 31, 2023, no 10b5 1 10b5 1
Rule 10b5-1 Arrangement Adopted [Flag]	false
Non-Rule 10b5-1 Arrangement Adopted [Flag]	false
Rule 10b5-1 Arrangement Terminated [Flag]	false
Non-Rule 10b5-1 Arrangement Terminated [Flag]	false

Significant Accounting Policies

Significant Accounting Policies (Policies)	3 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	BASIS OF PRESENTATION The accompanying unaudited financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) for interim financial information with the instructions to Form 10 10 01 not 10 10 September 30, 2023 The consolidated financial position, results of operations, and cash flows of Spire include the accounts of the Company and all its subsidiaries. Transactions and balances between consolidated entities have been eliminated from the consolidated financial statements of Spire. In compliance with GAAP, transactions between Spire Missouri and Spire Alabama and their affiliates, as well as intercompany balances on their balance sheets, have not NATURE OF OPERATIONS Note 10 The Company’s earnings are derived primarily from its Gas Utility segment. Due to the seasonal nature of the Utilities’ business and the volumetric Spire Missouri rate design, earnings are typically concentrated during the heating season of November April not
Public Utilities, Policy [Policy Text Block]	REGULATED OPERATIONS 980, Regulated Operations third may As authorized by the Missouri Public Service Commission (MoPSC), the Mississippi Public Service Commission (MSPSC) and the Alabama Public Service Commission (APSC), the Purchased Gas Adjustment (PGA) clauses and Gas Supply Adjustment (GSA) riders allow the Utilities to pass through to customers the cost of purchased gas supplies. Regulatory assets and liabilities related to the PGA clauses and the GSA riders are both labeled Unamortized Purchased Gas Adjustments herein. See additional information about regulatory assets and liabilities in Note 5
Derivatives, Policy [Policy Text Block]	DERIVATIVES 815, Derivatives and Hedging not first 2024, not December 31, 2023.
Transactions With Affiliates [Policy Text Block]	TRANSACTIONS WITH AFFILIATES Three Months Ended December 31, 2023 2022 Spire Missouri Purchases of natural gas from Spire Marketing $ 5.0 $ 28.5 Transportation services received from Spire STL Pipeline 8.2 8.1 Natural gas storage services from Spire Storage Salt Plains LLC 0.3 — Spire Alabama Purchases of natural gas from Spire Marketing $ 3.4 $ 1.1
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]	RESTRICTED CASH AND OTHER INVESTMENTS December 31, 2023 December 31, 2023 September 30, 2023 December 31, 2022
Business Combinations Policy [Policy Text Block]	BUSINESS COMBINATIONS January 20, 2024.
Accrued Capital Expenditures [Policy Text Block]	ACCRUED CAPITAL EXPENDITURES December 31, September 30, December 31, 2023 2023 2022 Spire $ 90.5 $ 104.3 $ 63.1 Spire Missouri 38.1 56.5 32.8 Spire Alabama 2.4 4.6 9.4
Receivable [Policy Text Block]	ACCOUNTS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES not Spire Spire Missouri Spire Alabama Three Months Ended December 31, 2023 2022 2023 2022 2023 2022 Allowance at beginning of period $ 32.5 $ 31.9 $ 26.2 $ 24.9 $ 5.7 $ 6.3 Provision for expected credit losses 4.1 4.1 3.6 3.8 0.3 0.2 Write-offs, net of recoveries (1.2 ) (1.5 ) (0.9 ) (0.5 ) (0.3 ) (1.0 ) Allowance at end of period $ 35.4 $ 34.5 $ 28.9 $ 28.2 $ 5.7 $ 5.5

Note 1 - Summary of Significa_2

Note 1 - Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Dec. 31, 2023
Notes Tables
Schedule of Related Party Transactions [Table Text Block]	Three Months Ended December 31, 2023 2022 Spire Missouri Purchases of natural gas from Spire Marketing $ 5.0 $ 28.5 Transportation services received from Spire STL Pipeline 8.2 8.1 Natural gas storage services from Spire Storage Salt Plains LLC 0.3 — Spire Alabama Purchases of natural gas from Spire Marketing $ 3.4 $ 1.1
Schedule Of Capital Expenditure Excluded From Statement Of Cash Flow [Table Text Block]	December 31, September 30, December 31, 2023 2023 2022 Spire $ 90.5 $ 104.3 $ 63.1 Spire Missouri 38.1 56.5 32.8 Spire Alabama 2.4 4.6 9.4
Accounts Receivable, Allowance for Credit Loss [Table Text Block]	Spire Spire Missouri Spire Alabama Three Months Ended December 31, 2023 2022 2023 2022 2023 2022 Allowance at beginning of period $ 32.5 $ 31.9 $ 26.2 $ 24.9 $ 5.7 $ 6.3 Provision for expected credit losses 4.1 4.1 3.6 3.8 0.3 0.2 Write-offs, net of recoveries (1.2 ) (1.5 ) (0.9 ) (0.5 ) (0.3 ) (1.0 ) Allowance at end of period $ 35.4 $ 34.5 $ 28.9 $ 28.2 $ 5.7 $ 5.5

Note 2 - Revenue (Tables)

Note 2 - Revenue (Tables)	3 Months Ended
	Dec. 31, 2023
Notes Tables
Disaggregation of Revenue [Table Text Block]	Three Months Ended December 31, 2023 2022 Spire Gas Utility: Residential $ 492.8 $ 518.0 Commercial and industrial 157.9 170.6 Transportation 32.6 30.9 Off-system and other incentive 6.4 7.6 Other customer revenue 5.5 4.4 Total revenue from contracts with customers 695.2 731.5 Changes in accrued revenue under alternative revenue programs 20.0 1.5 Total Gas Utility operating revenues 715.2 733.0 Gas Marketing 36.3 74.1 Midstream 14.9 15.2 Other 4.1 4.0 Total before eliminations 770.5 826.3 Intersegment eliminations (see Note 10, Information by Operating Segment) (13.9 ) (12.3 ) Total Operating Revenues $ 756.6 $ 814.0 Spire Missouri Residential $ 388.8 $ 400.6 Commercial and industrial 110.2 122.9 Transportation 9.0 9.1 Off-system and other incentive 4.1 5.1 Other customer revenue 2.5 2.0 Total revenue from contracts with customers 514.6 539.7 Changes in accrued revenue under alternative revenue programs 20.8 1.5 Total Operating Revenues $ 535.4 $ 541.2 Spire Alabama Residential $ 84.4 $ 96.3 Commercial and industrial 34.7 33.6 Transportation 20.8 19.3 Off-system and other incentive 2.3 2.4 Other customer revenue 0.9 1.2 Total revenue from contracts with customers 143.1 152.8 Changes in accrued revenue under alternative revenue programs (1.0 ) (0.4 ) Total Operating Revenues $ 142.1 $ 152.4
Schedule Of Taxes On Revenues [Table Text Block]	Three Months Ended December 31, 2023 2022 Spire $ 31.1 $ 30.4 Spire Missouri 22.5 22.1 Spire Alabama 6.9 6.8

Note 3 - Earnings Per Common _2

Note 3 - Earnings Per Common Share (Tables)	3 Months Ended
	Dec. 31, 2023
Notes Tables
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Three Months Ended December 31, 2023 2022 Basic Earnings Per Common Share: Net Income $ 85.1 $ 91.0 Less: Provision for preferred dividends 3.7 3.7 Income allocated to participating securities 0.1 0.1 Income Available to Common Shareholders $ 81.3 $ 87.2 Weighted Average Common Shares Outstanding (in millions) 53.5 52.4 Basic Earnings Per Common Share $ 1.52 $ 1.66 Diluted Earnings Per Common Share: Net Income $ 85.1 $ 91.0 Less: Provision for preferred dividends 3.7 3.7 Income allocated to participating securities 0.1 0.1 Income Available to Common Shareholders $ 81.3 $ 87.2 Weighted Average Common Shares Outstanding (in millions) 53.5 52.4 Dilutive Effect of forward sales of common stock, restricted stock and restricted stock units (in millions)* 0.1 0.2 Weighted Average Diluted Common Shares (in millions) 53.6 52.6 Diluted Earnings Per Common Share $ 1.52 $ 1.66 * Calculation excludes certain outstanding or potential common shares (shown in millions by period at the right) attributable to (1) stock units subject to performance or market conditions and (2) restricted stock, which could have a dilutive effect in the future 0.2 0.2

Note 5 - Regulatory Matters (Ta

Note 5 - Regulatory Matters (Tables)	3 Months Ended
	Dec. 31, 2023
Notes Tables
Schedule of Regulatory Assets and Liabilities [Table Text Block]	December 31, September 30, December 31, Spire 2023 2023 2022 Regulatory Assets: Current: Unamortized purchased gas adjustments $ 207.0 $ 293.2 $ 238.9 Other 49.4 55.1 30.2 Total Current Regulatory Assets 256.4 348.3 269.1 Noncurrent: Pension and postretirement benefit costs 255.3 261.0 277.3 Cost of removal 640.8 633.2 506.1 Future income taxes due from customers 145.6 144.5 138.6 Energy efficiency 57.5 56.3 59.1 Unamortized purchased gas adjustments 20.3 23.0 107.9 Other 147.4 131.2 131.7 Total Noncurrent Regulatory Assets 1,266.9 1,249.2 1,220.7 Total Regulatory Assets $ 1,523.3 $ 1,597.5 $ 1,489.8 Regulatory Liabilities: Current: Other $ 7.1 $ 7.3 $ 3.7 Total Current Regulatory Liabilities 7.1 7.3 3.7 Noncurrent: Deferred taxes due to customers 124.5 128.0 140.9 Pension and postretirement benefit costs 188.2 185.2 156.6 Accrued cost of removal 130.3 126.6 33.7 Unamortized purchased gas adjustments 23.7 11.2 — Other 20.5 21.4 13.7 Total Noncurrent Regulatory Liabilities 487.2 472.4 344.9 Total Regulatory Liabilities $ 494.3 $ 479.7 $ 348.6 December 31, September 30, December 31, Spire Missouri 2023 2023 2022 Regulatory Assets: Current: Unamortized purchased gas adjustments $ 194.1 $ 269.4 $ 181.2 Other 18.8 23.7 10.0 Total Current Regulatory Assets 212.9 293.1 191.2 Noncurrent: Future income taxes due from customers 137.3 136.2 130.1 Pension and postretirement benefit costs 185.5 189.1 197.4 Energy efficiency 57.5 56.3 59.1 Unamortized purchased gas adjustments 20.3 23.0 107.9 Cost of removal 97.0 97.0 23.9 Other 133.2 116.0 116.3 Total Noncurrent Regulatory Assets 630.8 617.6 634.7 Total Regulatory Assets $ 843.7 $ 910.7 $ 825.9 Regulatory Liabilities: Noncurrent: Deferred taxes due to customers $ 111.6 $ 114.8 $ 124.6 Pension and postretirement benefit costs 160.2 156.5 127.4 Accrued cost of removal 93.4 90.4 — Unamortized purchased gas adjustments 23.7 11.2 — Other 15.6 16.5 7.0 Total Noncurrent Regulatory Liabilities 404.5 389.4 259.0 Total Regulatory Liabilities $ 404.5 $ 389.4 $ 259.0 December 31, September 30, December 31, Spire Alabama 2023 2023 2022 Regulatory Assets: Current: Unamortized purchased gas adjustments $ 12.2 $ 21.7 $ 54.5 Other 18.8 19.9 12.8 Total Current Regulatory Assets 31.0 41.6 67.3 Noncurrent: Future income taxes due from customers 1.9 2.0 2.1 Pension and postretirement benefit costs 66.0 67.8 75.1 Cost of removal 543.7 536.2 482.2 Other 1.0 0.9 1.0 Total Noncurrent Regulatory Assets 612.6 606.9 560.4 Total Regulatory Assets $ 643.6 $ 648.5 $ 627.7 Regulatory Liabilities: Noncurrent: Pension and postretirement benefit costs $ 17.3 $ 17.9 $ 18.7 Other 3.4 3.3 3.5 Total Noncurrent Regulatory Liabilities 20.7 21.2 22.2 Total Regulatory Liabilities $ 20.7 $ 21.2 $ 22.2
Schedule of Regulatory Assets Not Earning Return [Table Text Block]	December 31, September 30, December 31, 2023 2023 2022 Spire Pension and postretirement benefit costs $ 134.0 $ 133.4 $ 127.0 Future income taxes due from customers 143.6 142.5 136.4 Unamortized purchased gas adjustments 214.4 292.4 289.1 Other 117.0 104.2 122.9 Total Regulatory Assets Not Earning a Return $ 609.0 $ 672.5 $ 675.4 Spire Missouri Pension and postretirement benefit costs $ 134.0 $ 133.4 $ 127.0 Future income taxes due from customers 137.3 136.2 130.1 Unamortized purchased gas adjustments 214.4 292.4 289.1 Other 117.0 104.2 122.9 Total Regulatory Assets Not Earning a Return $ 602.7 $ 666.2 $ 669.1

Note 6 - Financing (Tables)

Note 6 - Financing (Tables)	3 Months Ended
	Dec. 31, 2023
Notes Tables
Schedule of Short-Term Debt [Table Text Block]	Spire (Parent Only) Spire Missouri Spire Alabama Spire CP Term Spire Spire Consol- Program Loan Note Note idated Three Months Ended December 31, 2023 Highest borrowings outstanding $ 1,135.0 $ — $ 643.6 $ 132.5 $ 1,135.0 Lowest borrowings outstanding 955.5 — 526.5 107.9 955.5 Weighted average borrowings 1,043.5 — 583.3 119.8 1,043.5 Weighted average interest rate 5.7 % n/a 5.7 % 5.7 % 5.7 % As of December 31, 2023 Borrowings outstanding $ 1,047.5 $ — $ 633.3 $ 128.5 $ 1,047.5 Weighted average interest rate 5.7 % n/a 5.7 % 5.7 % 5.7 % As of September 30, 2023 Borrowings outstanding $ 955.5 $ — $ 540.6 $ 124.1 $ 955.5 Weighted average interest rate 5.6 % n/a 5.6 % 5.6 % 5.6 % As of December 31, 2022 Borrowings outstanding $ 1,227.0 $ — $ 651.2 $ 145.8 $ 1,227.0 Weighted average interest rate 4.9 % n/a 4.9 % 4.9 % 4.9 %
Summary Of Capitalized Interest [Table Text Block]	Three Months Ended December 31, 2023 2022 Spire $ 3.8 $ 1.6 Spire Missouri 1.2 0.5 Spire Alabama 0.4 0.7

Note 7 - Fair Value of Financ_2

Note 7 - Fair Value of Financial Instruments (Tables)	3 Months Ended
	Dec. 31, 2023
Notes Tables
Fair Value, by Balance Sheet Grouping [Table Text Block]	Classification of Estimated Fair Value Carrying Amount Fair Value Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Spire As of December 31, 2023 Cash and cash equivalents $ 4.8 $ 4.8 $ 4.8 $ — Notes payable 1,047.5 1,047.5 — 1,047.5 Long-term debt, including current portion 3,704.8 3,481.5 — 3,481.5 As of September 30, 2023 Cash and cash equivalents $ 5.6 $ 5.6 $ 5.6 $ — Notes payable 955.5 955.5 — 955.5 Long-term debt, including current portion 3,710.6 3,270.2 — 3,270.2 As of December 31, 2022 Cash and cash equivalents $ 4.8 $ 4.8 $ 4.8 $ — Notes payable 1,227.0 1,227.0 — 1,227.0 Long-term debt, including current portion 3,412.9 3,083.7 — 3,083.7 Spire Missouri As of December 31, 2023 Notes payable – associated companies $ 633.3 $ 633.3 $ — $ 633.3 Long-term debt, including current portion 1,785.8 1,689.5 — 1,689.5 As of September 30, 2023 Cash and cash equivalents $ 0.8 $ 0.8 $ 0.8 $ — Notes payable – associated companies 540.6 540.6 — 540.6 Long-term debt 1,785.4 1,592.4 — 1,592.4 As of December 31, 2022 Notes payable – associated companies $ 651.2 $ 651.2 $ — $ 651.2 Long-term debt, including current portion 1,638.1 1,497.7 — 1,497.7 Spire Alabama As of December 31, 2023 Notes payable – associated companies $ 128.5 $ 128.5 $ — $ 128.5 Long-term debt 746.0 701.7 — 701.7 As of September 30, 2023 Cash and cash equivalents $ 1.2 $ 1.2 $ 1.2 $ — Notes payable – associated companies 124.1 124.1 — 124.1 Long-term debt 745.9 648.0 — 648.0 As of December 31, 2022 Notes payable – associated companies $ 145.8 $ 145.8 $ — $ 145.8 Long-term debt 745.6 674.5 — 674.5

Note 8 - Fair Value Measureme_2

Note 8 - Fair Value Measurements (Tables)	3 Months Ended
	Dec. 31, 2023
Notes Tables
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Effects of Netting and Cash Margin Receivables /Payables Total As of December 31, 2023 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 22.0 $ — $ — $ 22.0 NYMEX/ICE natural gas contracts 4.7 — (4.7 ) — Gas Marketing: NYMEX/ICE natural gas contracts 13.2 — (13.2 ) — Natural gas commodity contracts — 45.5 (1.4 ) 44.1 Other: U.S. stock/bond mutual funds 14.6 — — 14.6 U.S. bonds 21.6 — — 21.6 Global bonds 1.4 — — 1.4 Interest rate swaps — 22.7 — 22.7 Total $ 77.5 $ 68.2 $ (19.3 ) $ 126.4 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 60.7 $ — $ (60.7 ) $ — Gasoline and heating oil contracts — 0.4 (0.4 ) — Gas Marketing: NYMEX/ICE natural gas contracts 32.7 — (32.7 ) — Natural gas commodity contracts — 24.5 (1.4 ) 23.1 Other: Interest rate swaps — 2.0 — 2.0 Total $ 93.4 $ 26.9 $ (95.2 ) $ 25.1 Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Effects of Netting and Cash Margin Receivables /Payables Total As of September 30, 2023 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 20.4 $ — $ — $ 20.4 NYMEX/ICE natural gas contracts 6.3 — (6.3 ) — Gasoline and heating oil contracts — 0.1 (0.1 ) — Gas Marketing: NYMEX/ICE natural gas contracts 10.1 — (10.1 ) — Natural gas commodity contracts — 36.7 (3.6 ) 33.1 Other: U.S. stock/bond mutual funds 37.6 — — 37.6 Interest rate swaps — 44.2 — 44.2 Total $ 74.4 $ 81.0 $ (20.1 ) $ 135.3 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 50.8 $ — $ (44.0 ) $ 6.8 Gas Marketing: NYMEX/ICE natural gas contracts 21.8 — (21.8 ) — Natural gas commodity contracts — 27.6 (3.6 ) 24.0 Total $ 72.6 $ 27.6 $ (69.4 ) $ 30.8 As of December 31, 2022 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 19.5 $ — $ — $ 19.5 NYMEX/ICE natural gas contracts 0.4 — (0.4 ) — Gasoline and heating oil contracts 0.2 — (0.2 ) — Gas Marketing: NYMEX/ICE natural gas contracts 52.0 — (52.0 ) — Natural gas commodity contracts * — 92.9 (13.2 ) 79.7 Other: U.S. stock/bond mutual funds 28.3 — — 28.3 Interest rate swaps * — 61.4 — 61.4 Total $ 100.4 $ 154.3 $ (65.8 ) $ 188.9 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 35.7 $ — $ (35.7 ) $ — Gasoline and heating oil contracts 0.2 — (0.2 ) — Gas Marketing: NYMEX/ICE natural gas contracts 58.4 — (58.4 ) — Natural gas commodity contracts * — 71.1 (13.2 ) 57.9 Other: Interest rate swaps * — 0.8 — 0.8 Total $ 94.3 $ 71.9 $ (107.5 ) $ 58.7 Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Effects of Netting and Cash Margin Receivables /Payables Total As of December 31, 2023 ASSETS U.S. stock/bond mutual funds $ 22.0 $ — $ — $ 22.0 NYMEX/ICE natural gas contracts 4.7 — (4.7 ) — Total $ 26.7 $ — $ (4.7 ) $ 22.0 LIABILITIES NYMEX/ICE natural gas contracts $ 60.7 $ — $ (60.7 ) $ — Gasoline and heating oil contracts — 0.4 (0.4 ) — Total $ 60.7 $ 0.4 $ (61.1 ) $ — As of September 30, 2023 ASSETS U.S. stock/bond mutual funds $ 20.4 $ — $ — $ 20.4 NYMEX/ICE natural gas contracts 6.3 — (6.3 ) — Gasoline and heating oil contracts — 0.1 (0.1 ) — Total $ 26.7 $ 0.1 $ (6.4 ) $ 20.4 LIABILITIES NYMEX/ICE natural gas contracts $ 50.8 $ — $ (44.0 ) $ 6.8 As of December 31, 2022 ASSETS U.S. stock/bond mutual funds $ 19.5 $ — $ — $ 19.5 NYMEX/ICE natural gas contracts 0.4 — (0.4 ) — Gasoline and heating oil contracts 0.2 — (0.2 ) — Total $ 20.1 $ — $ (0.6 ) $ 19.5 LIABILITIES NYMEX/ICE natural gas contracts $ 35.7 $ — $ (35.7 ) $ — Gasoline and heating oil contracts 0.2 — (0.2 ) — Total $ 35.9 $ — $ (35.9 ) $ —

Note 9 - Pension Plans and Ot_2

Note 9 - Pension Plans and Other Postretirement Benefits (Tables)	3 Months Ended
	Dec. 31, 2023
Notes Tables
Schedule of Net Benefit Costs [Table Text Block]	Three Months Ended December 31, 2023 2022 Spire Service cost – benefits earned during the period $ 4.0 $ 4.1 Interest cost on projected benefit obligation 6.8 6.4 Expected return on plan assets (6.3 ) (6.4 ) Amortization of prior service credit (1.1 ) (1.1 ) Amortization of actuarial loss 1.6 1.6 Loss on lump-sum settlements — 8.6 Subtotal 5.0 13.2 Regulatory adjustment 8.7 1.8 Net pension cost $ 13.7 $ 15.0 Spire Missouri Service cost – benefits earned during the period $ 2.6 $ 2.8 Interest cost on projected benefit obligation 4.8 4.5 Expected return on plan assets (4.3 ) (4.5 ) Amortization of prior service credit (0.5 ) (0.5 ) Amortization of actuarial loss 1.5 1.5 Subtotal 4.1 3.8 Regulatory adjustment 6.3 8.1 Net pension cost $ 10.4 $ 11.9 Spire Alabama Service cost – benefits earned during the period $ 1.2 $ 1.1 Interest cost on projected benefit obligation 1.3 1.3 Expected return on plan assets (1.2 ) (1.1 ) Amortization of prior service credit (0.6 ) (0.6 ) Amortization of actuarial loss 0.2 0.1 Loss on lump-sum settlements — 8.6 Subtotal 0.9 9.4 Regulatory adjustment 2.2 (6.5 ) Net pension cost $ 3.1 $ 2.9 Three Months Ended December 31, 2023 2022 Spire Service cost – benefits earned during the period $ 1.1 $ 1.2 Interest cost on accumulated postretirement benefit obligation 2.1 2.1 Expected return on plan assets (4.0 ) (3.9 ) Amortization of prior service cost 0.1 0.1 Amortization of actuarial gain (1.0 ) (1.0 ) Subtotal (1.7 ) (1.5 ) Regulatory adjustment 0.2 0.1 Net postretirement benefit income $ (1.5 ) $ (1.4 ) Spire Missouri Service cost – benefits earned during the period $ 0.9 $ 1.0 Interest cost on accumulated postretirement benefit obligation 1.6 1.6 Expected return on plan assets (2.7 ) (2.6 ) Amortization of prior service cost 0.2 0.2 Amortization of actuarial gain (0.9 ) (0.8 ) Subtotal (0.9 ) (0.6 ) Regulatory adjustment 0.6 0.6 Net postretirement benefit income $ (0.3 ) $ — Spire Alabama Service cost – benefits earned during the period $ 0.2 $ 0.2 Interest cost on accumulated postretirement benefit obligation 0.5 0.4 Expected return on plan assets (1.3 ) (1.2 ) Amortization of prior service credit (0.1 ) (0.1 ) Amortization of actuarial gain — (0.1 ) Subtotal (0.7 ) (0.8 ) Regulatory adjustment (0.4 ) (0.5 ) Net postretirement benefit income $ (1.1 ) $ (1.3 )

Note 10 - Information by Oper_2

Note 10 - Information by Operating Segment (Tables)	3 Months Ended
	Dec. 31, 2023
Notes Tables
Schedule of Segment Reporting Information, by Segment [Table Text Block]	Gas Utility Gas Marketing Midstream Other Eliminations Consolidated Three Months Ended December 31, 2023 Revenues from external customers $ 715.2 $ 36.3 $ 5.0 $ 0.1 $ — $ 756.6 Intersegment revenues — — 9.9 4.0 (13.9 ) — Total Operating Revenues 715.2 36.3 14.9 4.1 (13.9 ) 756.6 Depreciation and amortization expense 64.2 0.4 2.3 0.1 — 67.0 Interest expense 39.0 — 1.8 24.0 (14.2 ) 50.6 Income tax expense 15.7 3.8 0.6 0.9 — 21.0 Net economic earnings (loss) 75.8 7.2 2.4 (2.7 ) — 82.7 Capital expenditures 174.9 — 52.0 — (0.4 ) 226.5 Gas Utility Gas Marketing Midstream Other Eliminations Consolidated Three Months Ended December 31, 2022 Revenues from external customers $ 733.0 $ 74.1 $ 6.8 $ 0.1 $ — $ 814.0 Intersegment revenues — — 8.4 3.9 (12.3 ) — Total Operating Revenues 733.0 74.1 15.2 4.0 (12.3 ) 814.0 Depreciation and amortization expense 59.7 0.3 1.9 0.2 — 62.1 Interest expense 32.1 — 1.9 19.5 (9.9 ) 43.6 Income tax expense (benefit) 12.4 10.5 1.4 (2.7 ) — 21.6 Net economic earnings (loss) 62.9 25.7 3.8 (7.3 ) — 85.1 Capital expenditures 146.3 0.2 7.7 0.6 — 154.8
Reconciliation Of Consolidated Net Economic Earnings To Consolidated Net Income [Table Text Block]	Three Months Ended December 31, 2023 2022 Net Income $ 85.1 $ 91.0 Adjustments, pre-tax: Fair value and timing adjustments (5.2 ) (7.8 ) Acquisition activities 1.9 — Income tax adjustments 0.9 1.9 Net Economic Earnings $ 82.7 $ 85.1
Reconciliation of Assets from Segment to Consolidated [Table Text Block]	December 31, September 30, December 31, 2023 2023 2022 Total Assets: Gas Utility $ 8,736.7 $ 8,486.7 $ 8,355.1 Gas Marketing 207.0 332.0 492.4 Midstream 633.9 574.3 466.6 Other 2,755.1 2,533.3 2,882.8 Eliminations (1,701.0 ) (1,612.7 ) (1,869.2 ) Total Assets $ 10,631.7 $ 10,313.6 $ 10,327.7

Note 1 - Summary of Significa_3

Note 1 - Summary of Significant Accounting Policies (Details Textual) $ in Millions		3 Months Ended	12 Months Ended
	Jan. 20, 2024 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Number of Reportable Segments		3	3
Restricted Cash		$ 20.5	$ 20.2	$ 14.2
MoGas Pipeline [Member] | Subsequent Event [Member]
Payments to Acquire Businesses, Gross	$ 177.6
Other Income [Member]
Gain on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring		$ 8.2

Note 1 - Summary of Significa_4

Note 1 - Summary of Significant Accounting Policies - Transactions with Affiliates (Details) - Affiliated Entity [Member] - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Regulated Operation [Member] | Spire Marketing [Member] | Spire Missouri [Member]
Purchases of natural gas from Spire Marketing	$ 5	$ 28.5
Regulated Operation [Member] | Spire Marketing [Member] | Spire Alabama Inc [Member]
Purchases of natural gas from Spire Marketing	3.4	1.1
Unregulated Operation [Member] | Spire S T L Pipeline L L C [Member] | Spire Missouri [Member]
Transportation services received from Spire STL Pipeline	8.2	8.1
Unregulated Operation [Member] | Spire Storage Salt Plains LLC [Member] | Spire Missouri [Member]
Transportation services received from Spire STL Pipeline	$ 0.3	$ 0

Note 1 - Summary of Significa_5

Note 1 - Summary of Significant Accounting Policies - Accrued Capital Expenditures Excluded from Capital Expenditures in the Statements of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2023
Accrued capital expenditures	$ 90.5	$ 63.1	$ 104.3
Spire Missouri [Member]
Accrued capital expenditures	38.1	32.8	56.5
Spire Alabama Inc [Member]
Accrued capital expenditures	$ 2.4	$ 9.4	$ 4.6

Note 1 - Summary of Significa_6

Note 1 - Summary of Significant Accounting Policies - Activity in the Allowance for Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Allowance at beginning of period	$ 32.5	$ 31.9
Provision for expected credit losses	4.1	4.1
Write-offs, net of recoveries	(1.2)	(1.5)
Allowance at end of period	35.4	34.5
Spire Missouri [Member]
Allowance at beginning of period	26.2	24.9
Provision for expected credit losses	3.6	3.8
Write-offs, net of recoveries	(0.9)	(0.5)
Allowance at end of period	28.9	28.2
Spire Alabama Inc [Member]
Allowance at beginning of period	5.7	6.3
Provision for expected credit losses	0.3	0.2
Write-offs, net of recoveries	(0.3)	(1)
Allowance at end of period	$ 5.7	$ 5.5

Note 2 - Revenue - Disaggregate

Note 2 - Revenue - Disaggregated of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating Revenues	$ 756.6	$ 814
Consolidation, Eliminations [Member]
Operating Revenues	(13.9)	(12.3)
Gas Utility [Member] | Operating Segments [Member]
Operating Revenues	715.2	733
Gas Marketing [Member] | Operating Segments [Member]
Operating Revenues	36.3	74.1
Midstream [Member] | Operating Segments [Member]
Operating Revenues	14.9	15.2
Other Segments [Member] | Consolidation, Eliminations [Member]
Operating Revenues	4.1	4
Spire Missouri [Member]
Operating Revenues	535.4	541.2
Spire Missouri [Member] | Gas Utility [Member] | Operating Segments [Member]
Revenue	514.6	539.7
Changes in accrued revenue under alternative revenue programs	20.8	1.5
Spire Missouri [Member] | Gas Utility [Member] | Operating Segments [Member] | Residential [Member]
Revenue	388.8	400.6
Spire Missouri [Member] | Gas Utility [Member] | Operating Segments [Member] | Commercial and Industrial [Member]
Revenue	110.2	122.9
Spire Missouri [Member] | Gas Utility [Member] | Operating Segments [Member] | Transportation [Member]
Revenue	9	9.1
Spire Missouri [Member] | Gas Utility [Member] | Operating Segments [Member] | Off-system and Other Incentive [Member]
Revenue	4.1	5.1
Spire Missouri [Member] | Gas Utility [Member] | Operating Segments [Member] | Other Customer Revenue [Member]
Revenue	2.5	2
Spire Alabama Inc [Member]
Operating Revenues	142.1	152.4
Spire Alabama Inc [Member] | Gas Utility [Member] | Operating Segments [Member]
Revenue	143.1	152.8
Changes in accrued revenue under alternative revenue programs	(1)	(0.4)
Spire Alabama Inc [Member] | Gas Utility [Member] | Operating Segments [Member] | Residential [Member]
Revenue	84.4	96.3
Spire Alabama Inc [Member] | Gas Utility [Member] | Operating Segments [Member] | Commercial and Industrial [Member]
Revenue	34.7	33.6
Spire Alabama Inc [Member] | Gas Utility [Member] | Operating Segments [Member] | Transportation [Member]
Revenue	20.8	19.3
Spire Alabama Inc [Member] | Gas Utility [Member] | Operating Segments [Member] | Off-system and Other Incentive [Member]
Revenue	2.3	2.4
Spire Alabama Inc [Member] | Gas Utility [Member] | Operating Segments [Member] | Other Customer Revenue [Member]
Revenue	0.9	1.2
Spire [Member]
Operating Revenues	756.6	814
Spire [Member] | Operating Segments [Member]
Operating Revenues	770.5	826.3
Spire [Member] | Consolidation, Eliminations [Member]
Operating Revenues	(13.9)
Spire [Member] | Segment Reconciling Items [Member]
Operating Revenues		(12.3)
Spire [Member] | Gas Utility [Member] | Operating Segments [Member]
Revenue	695.2	731.5
Changes in accrued revenue under alternative revenue programs	20	1.5
Total Gas Utility operating revenues	715.2	733
Spire [Member] | Gas Utility [Member] | Operating Segments [Member] | Residential [Member]
Revenue	492.8	518
Spire [Member] | Gas Utility [Member] | Operating Segments [Member] | Commercial and Industrial [Member]
Revenue	157.9	170.6
Spire [Member] | Gas Utility [Member] | Operating Segments [Member] | Transportation [Member]
Revenue	32.6	30.9
Spire [Member] | Gas Utility [Member] | Operating Segments [Member] | Off-system and Other Incentive [Member]
Revenue	6.4	7.6
Spire [Member] | Gas Utility [Member] | Operating Segments [Member] | Other Customer Revenue [Member]
Revenue	5.5	4.4
Spire [Member] | Gas Marketing [Member] | Operating Segments [Member]
Unregulated Operating Revenue	36.3	74.1
Spire [Member] | Midstream [Member] | Operating Segments [Member]
Unregulated Operating Revenue	14.9	15.2
Spire [Member] | Other Segments [Member] | Operating Segments [Member]
Unregulated Operating Revenue	$ 4.1	$ 4

Note 2 - Revenue - Taxes Associ

Note 2 - Revenue - Taxes Associated with Natural Gas Utility Services (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Gross Receipts Tax Amounts	$ 31.1	$ 30.4
Spire Missouri [Member]
Gross Receipts Tax Amounts	22.5	22.1
Spire Alabama Inc [Member]
Gross Receipts Tax Amounts	$ 6.9	$ 6.8

Note 3 - Earnings Per Common _3

Note 3 - Earnings Per Common Share - Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended
		Dec. 31, 2023	Dec. 31, 2022
Net Income		$ 85.1	$ 91
Provision for preferred dividends		3.7	3.7
Income allocated to participating securities		0.1	0.1
Income Available to Common Shareholders		$ 81.3	$ 87.2
Basic (in shares)		53.5	52.4
Basic Earnings Per Common Share (in dollars per share)		$ 1.52	$ 1.66
Dilutive Effect of forward sales of common stock, restricted stock and restricted stock units (in millions)* (in shares)	[1]	0.1	0.2
Weighted Average Diluted Common Shares (in millions) (in shares)		53.6	52.6
Diluted Earnings Per Common Share (in dollars per share)		$ 1.52	$ 1.66
* Calculation excludes certain outstanding or potential common shares (shown in millions by period at the right) attributable to (1) stock units subject to performance or market conditions and (2) restricted stock, which could have a dilutive effect in the future (in shares)		0.2	0.2
[1]Calculation excludes certain outstanding or potential common shares (shown in millions by period at the right) attributable to (1) forward sales of common stock, (2) stock units subject to performance or market conditions, and (3) restricted stock, which could have a dilutive effect in the future

Note 4 - Shareholders' Equity (

Note 4 - Shareholders' Equity (Details Textual) - At The Market Program [Member] - USD ($) $ in Millions	Dec. 11, 2023	Jan. 25, 2024	Dec. 31, 2023
Forward Sales Agreements, Block Sales, Shares (in shares)	1,744,549
Forward Sales Agreements, Proceeds If Settled			$ 112.2
Subsequent Event [Member]
Sale of Stock, Maximum Aggregate Offering Price		$ 200

Note 5 - Regulatory Matters (De

Note 5 - Regulatory Matters (Details Textual) - USD ($) $ in Millions	Jan. 17, 2024	Jan. 01, 2024	Dec. 14, 2023	Dec. 13, 2023	Dec. 01, 2023	Oct. 04, 2023	Apr. 30, 2023	Apr. 20, 2023	Jan. 01, 2023	Dec. 31, 2023
Spire Missouri [Member] | Missouri Public Service Commission [Member] | Infrastructure System Replacement Surcharge [Member]
Public Utilities, Approved Rate Increase (Decrease), Amount						$ 12.4		$ 7.7
Spire Missouri [Member] | Missouri Public Service Commission [Member] | Infrastructure System Replacement Surcharge [Member] | Subsequent Event [Member]
Public Utilities, Requested Rate Increase (Decrease), Amount	$ 17.3
Spire Alabama Inc [Member] | Alabama Public Service Commission [Member]
Annual Revenue Increase From Rates, Amount									$ 15
Spire Alabama Inc [Member] | Alabama Public Service Commission [Member] | Subsequent Event [Member]
Annual Revenue Increase From Rates, Amount		$ 14.3
Spire Gulf [Member]
Annual Revenue Increase From Rates, Amount				$ 2.7
Public Utilities, Approved Rate, Increase Decrease Annualized Revenue					$ 2		$ 1.8		2.5
Spire Mississippi [Member]
Public Utilities, Approved Rate, Increase Decrease Annualized Revenue			$ 0.8						$ 0.8
Future Income Taxes Due From Customers and Pension and Other Postretirement Benefit Costs [Member]
Remaining Recovery Period of Regulatory Assets for which No Return on Investment During Recovery Period is Provided (Year)										20 years
PGA Assets [Member]
Remaining Recovery Period of Regulatory Assets for which No Return on Investment During Recovery Period is Provided (Year)										2 years
PGA Assets Not Earning A Return [Member]
Remaining Recovery Period of Regulatory Assets for which No Return on Investment During Recovery Period is Provided (Year)										15 years

Note 5 - Regulatory Matters - R

Note 5 - Regulatory Matters - Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Regulatory assets	$ 256.4	$ 348.3	$ 269.1
Regulatory Assets Noncurrent	1,266.9	1,249.2	1,220.7
Total Regulatory Assets	1,523.3	1,597.5	1,489.8
Regulatory Liability Current	7.1	7.3	3.7
Regulatory Liability Noncurrent	487.2	472.4	344.9
Total Regulatory Liabilities	494.3	479.7	348.6
Spire Missouri [Member]
Regulatory assets	212.9	293.1	191.2
Regulatory Assets Noncurrent	630.8	617.6	634.7
Total Regulatory Assets	843.7	910.7	825.9
Regulatory Liability Noncurrent	404.5	389.4	259
Total Regulatory Liabilities	404.5	389.4	259
Spire Alabama Inc [Member]
Regulatory assets	31	41.6	67.3
Regulatory Assets Noncurrent	612.6	606.9	560.4
Total Regulatory Assets	643.6	648.5	627.7
Regulatory Liability Noncurrent	20.7	21.2	22.2
Total Regulatory Liabilities	20.7	21.2	22.2
Unamortized Purchased Gas Adjustments Asset [Member]
Regulatory assets	207	293.2	238.9
Regulatory Assets Noncurrent	20.3	23	107.9
Regulatory Liability Noncurrent	23.7	11.2	0
Unamortized Purchased Gas Adjustments Asset [Member] | Spire Missouri [Member]
Regulatory assets	194.1	269.4	181.2
Regulatory Assets Noncurrent	20.3	23	107.9
Regulatory Liability Noncurrent	23.7	11.2	0
Unamortized Purchased Gas Adjustments Asset [Member] | Spire Alabama Inc [Member]
Regulatory assets	12.2	21.7	54.5
Other Regulatory Assets (Liabilities) [Member]
Regulatory assets	49.4	55.1	30.2
Regulatory Assets Noncurrent	147.4	131.2	131.7
Regulatory Liability Current	7.1	7.3	3.7
Regulatory Liability Noncurrent	20.5	21.4	13.7
Other Regulatory Assets (Liabilities) [Member] | Spire Missouri [Member]
Regulatory assets	18.8	23.7	10
Regulatory Assets Noncurrent	133.2	116	116.3
Regulatory Liability Noncurrent	15.6	16.5	7
Other Regulatory Assets (Liabilities) [Member] | Spire Alabama Inc [Member]
Regulatory assets	18.8	19.9	12.8
Regulatory Assets Noncurrent	1	0.9	1
Regulatory Liability Noncurrent	3.4	3.3	3.5
Pension and Other Postretirement Plans Costs [Member]
Regulatory Assets Noncurrent	255.3	261	277.3
Regulatory Liability Noncurrent	188.2	185.2	156.6
Pension and Other Postretirement Plans Costs [Member] | Spire Missouri [Member]
Regulatory Assets Noncurrent	185.5	189.1	197.4
Regulatory Liability Noncurrent	160.2	156.5	127.4
Pension and Other Postretirement Plans Costs [Member] | Spire Alabama Inc [Member]
Regulatory Assets Noncurrent	66	67.8	75.1
Regulatory Liability Noncurrent	17.3	17.9	18.7
Deferred Income Tax Charge [Member]
Regulatory Assets Noncurrent	145.6	144.5	138.6
Deferred Income Tax Charge [Member] | Spire Missouri [Member]
Regulatory Assets Noncurrent	137.3	136.2	130.1
Deferred Income Tax Charge [Member] | Spire Alabama Inc [Member]
Regulatory Assets Noncurrent	1.9	2	2.1
Removal Costs [Member]
Regulatory Assets Noncurrent	640.8	633.2	506.1
Regulatory Liability Noncurrent	130.3	126.6	33.7
Removal Costs [Member] | Spire Missouri [Member]
Regulatory Assets Noncurrent	97	97	23.9
Regulatory Liability Noncurrent	93.4	90.4	0
Removal Costs [Member] | Spire Alabama Inc [Member]
Regulatory Assets Noncurrent	543.7	536.2	482.2
Renewable Energy Program [Member]
Regulatory Assets Noncurrent	57.5	56.3	59.1
Renewable Energy Program [Member] | Spire Missouri [Member]
Regulatory Assets Noncurrent	57.5	56.3	59.1
Estimated Deferred Taxes Due to Customers [Member]
Regulatory Liability Noncurrent	124.5	128	140.9
Estimated Deferred Taxes Due to Customers [Member] | Spire Missouri [Member]
Regulatory Liability Noncurrent	$ 111.6	$ 114.8	$ 124.6

Note 5 - Regulatory Matters -_2

Note 5 - Regulatory Matters - Regulatory Assets Not Earning a Return (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Regulatory assets not earning a return	$ 609	$ 672.5	$ 675.4
Spire Missouri [Member]
Regulatory assets not earning a return	602.7	666.2	669.1
Pension and Other Postretirement Plans Costs [Member]
Regulatory assets not earning a return	134	133.4	127
Pension and Other Postretirement Plans Costs [Member] | Spire Missouri [Member]
Regulatory assets not earning a return	134	133.4	127
Deferred Income Tax Charge [Member]
Regulatory assets not earning a return	143.6	142.5	136.4
Deferred Income Tax Charge [Member] | Spire Missouri [Member]
Regulatory assets not earning a return	137.3	136.2	130.1
Unamortized Purchased Gas Adjustments Asset [Member]
Regulatory assets not earning a return	214.4	292.4	289.1
Unamortized Purchased Gas Adjustments Asset [Member] | Spire Missouri [Member]
Regulatory assets not earning a return	214.4	292.4	289.1
Other Regulatory Assets (Liabilities) [Member]
Regulatory assets not earning a return	117	104.2	122.9
Other Regulatory Assets (Liabilities) [Member] | Spire Missouri [Member]
Regulatory assets not earning a return	$ 117	$ 104.2	$ 122.9

Note 6 - Financing (Details Tex

Note 6 - Financing (Details Textual) - USD ($) $ in Thousands	Jan. 03, 2024	Dec. 31, 2023
Commercial Paper [Member] | Parent Company [Member]
Short Term Borrowings Used to Support Lending to Utilities		$ 810,800
Spire Missouri [Member] | Unsecured Term Loan [Member] | London Interbank Offered Rate LIBOR 1 [Member]
Line of Credit Facility, Covenant, Percentage of Total Capitalization		65%
Spire Missouri [Member] | Loans Payable [Member] | Subsequent Event [Member]
Debt Instrument, Face Amount	$ 200,000
Debt Instrument, Interest Rate, Basis for Effective Rate	0.10%
Spire Missouri [Member] | Loans Payable [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] | Subsequent Event [Member]
Debt Instrument, Basis Spread on Variable Rate	0.90%
Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity		$ 1,300,000
Long-Term Line of Credit		$ 0
Revolving Credit Facility [Member] | Maximum [Member]
Line of Credit Facility, Covenant, Percentage of Total Capitalization		70%
Revolving Credit Facility [Member] | Spire [Member]
Line of Credit Facility, Maximum Borrowing Capacity		$ 450,000
Revolving Credit Facility [Member] | Spire Missouri [Member]
Line of Credit Facility, Maximum Borrowing Capacity		575,000
Revolving Credit Facility [Member] | Spire Alabama Inc [Member]
Line of Credit Facility, Maximum Borrowing Capacity		$ 275,000

Note 6 - Financing - Short-term

Note 6 - Financing - Short-term Borrowings (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Highest borrowings outstanding	$ 1,135
Lowest borrowings outstanding	955.5
Weighted average borrowings	$ 1,043.5
Weighted average interest rate	5.70%
Borrowings outstanding	$ 1,047.5	$ 955.5	$ 1,227
Weighted average interest rate	5.70%	5.60%	4.90%
Spire Alabama Inc [Member] | Spire Note [Member]
Highest borrowings outstanding	$ 132.5
Lowest borrowings outstanding	107.9
Weighted average borrowings	$ 119.8
Weighted average interest rate	5.70%
Borrowings outstanding	$ 128.5	$ 124.1	$ 145.8
Weighted average interest rate	5.70%	5.60%	4.90%
Spire Note [Member] | Spire Missouri [Member]
Highest borrowings outstanding	$ 643.6
Lowest borrowings outstanding	526.5
Weighted average borrowings	$ 583.3
Weighted average interest rate	5.70%
Borrowings outstanding	$ 633.3	$ 540.6	$ 651.2
Weighted average interest rate	5.70%	5.60%	4.90%
Parent Company [Member] | Commercial Paper [Member]
Highest borrowings outstanding	$ 1,135
Lowest borrowings outstanding	955.5
Weighted average borrowings	$ 1,043.5
Weighted average interest rate	5.70%
Borrowings outstanding	$ 1,047.5	$ 955.5	$ 1,227
Weighted average interest rate	5.70%	5.60%	4.90%

Note 6 - Financing - Capitalize

Note 6 - Financing - Capitalized Interest Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Interest Paid Capitalized	$ 3.8	$ 1.6
Spire Missouri [Member]
Interest Paid Capitalized	1.2	0.5
Spire Alabama Inc [Member]
Interest Paid Capitalized	$ 0.4	$ 0.7

Note 7 - Fair Value of Financ_3

Note 7 - Fair Value of Financial Instruments - Estimated Fair Value of Financial Instruments Not Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Reported Value Measurement [Member]
Cash and cash equivalents	$ 4.8	$ 5.6	$ 4.8
Notes payable	1,047.5	955.5	1,227
Long-term debt, including current portion	3,704.8	3,710.6	3,412.9
Reported Value Measurement [Member] | Spire Missouri [Member]
Cash and cash equivalents		0.8
Long-term debt, including current portion	1,785.8	1,785.4	1,638.1
Notes payable – associated companies	633.3	540.6	651.2
Reported Value Measurement [Member] | Spire Alabama Inc [Member]
Cash and cash equivalents		1.2
Long-term debt, including current portion	746	745.9	745.6
Notes payable – associated companies	128.5	124.1	145.8
Estimate of Fair Value Measurement [Member]
Cash and cash equivalents	4.8	5.6	4.8
Notes payable	1,047.5	955.5	1,227
Long-term debt, including current portion	3,481.5	3,270.2	3,083.7
Estimate of Fair Value Measurement [Member] | Spire Missouri [Member]
Cash and cash equivalents		0.8
Long-term debt, including current portion	1,689.5	1,592.4	1,497.7
Notes payable – associated companies	633.3	540.6	651.2
Estimate of Fair Value Measurement [Member] | Spire Alabama Inc [Member]
Cash and cash equivalents		1.2
Long-term debt, including current portion	701.7	648	674.5
Notes payable – associated companies	128.5	124.1	145.8
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	4.8	5.6	4.8
Notes payable	0	0	0
Long-term debt, including current portion	0	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Spire Missouri [Member]
Cash and cash equivalents		0.8
Long-term debt, including current portion	0	0	0
Notes payable – associated companies	0	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Spire Alabama Inc [Member]
Cash and cash equivalents		1.2
Long-term debt, including current portion	0	0	0
Notes payable – associated companies	0	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents	0	0	0
Notes payable	1,047.5	955.5	1,227
Long-term debt, including current portion	3,481.5	3,270.2	3,083.7
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Spire Missouri [Member]
Cash and cash equivalents		0
Long-term debt, including current portion	1,689.5	1,592.4	1,497.7
Notes payable – associated companies	633.3	540.6	651.2
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Spire Alabama Inc [Member]
Cash and cash equivalents		0
Long-term debt, including current portion	701.7	648	674.5
Notes payable – associated companies	$ 128.5	$ 124.1	$ 145.8

Note 8 - Fair Value Measureme_3

Note 8 - Fair Value Measurements - Schedule of Derivative Assets and Liabilities, Including Receivables and Payables (Details) - Fair Value, Recurring [Member] - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Derivative Asset Fair Value Gross Asset	$ 126.4
Effects of netting, asset	(19.3)
Derivative Liability Fair Value Gross Liability	25.1
Effects of netting, liability	(95.2)
Fair Value, Inputs, Level 1 [Member]
Derivative Asset Fair Value Gross Asset	77.5
Derivative Liability Fair Value Gross Liability	93.4
Fair Value, Inputs, Level 2 [Member]
Derivative Asset Fair Value Gross Asset	68.2
Derivative Liability Fair Value Gross Liability	26.9
U S Stock And Bond Mutual Funds [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	22
Effects of netting, asset	0
U S Stock And Bond Mutual Funds [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	14.6
Effects of netting, asset	0
U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	22
U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	14.6
U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	0
U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 2 [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	0
N Y M E X And I C E Natural Gas Contracts [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	0
Effects of netting, asset	(4.7)
Derivative Liability Fair Value Gross Liability	0
Effects of netting, liability	(60.7)
N Y M E X And I C E Natural Gas Contracts [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	0
Effects of netting, asset	(13.2)
Derivative Liability Fair Value Gross Liability	0
Effects of netting, liability	(32.7)
N Y M E X And I C E Natural Gas Contracts [Member] | Fair Value, Inputs, Level 1 [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	4.7
Derivative Liability Fair Value Gross Liability	60.7
N Y M E X And I C E Natural Gas Contracts [Member] | Fair Value, Inputs, Level 1 [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	13.2
Derivative Liability Fair Value Gross Liability	32.7
N Y M E X And I C E Natural Gas Contracts [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	0
Derivative Liability Fair Value Gross Liability	0
N Y M E X And I C E Natural Gas Contracts [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	0
Derivative Liability Fair Value Gross Liability	0
Gasoline And Heating Oil Contracts [Member] | Gas Utility [Member]
Derivative Liability Fair Value Gross Liability	0
Effects of netting, liability	(0.4)
Gasoline And Heating Oil Contracts [Member] | Fair Value, Inputs, Level 1 [Member] | Gas Utility [Member]
Derivative Liability Fair Value Gross Liability	0
Gasoline And Heating Oil Contracts [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Utility [Member]
Derivative Liability Fair Value Gross Liability	0.4
Natural Gas Commodity Contracts [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	44.1
Effects of netting, asset	(1.4)
Derivative Liability Fair Value Gross Liability	23.1
Effects of netting, liability	(1.4)
Natural Gas Commodity Contracts [Member] | Fair Value, Inputs, Level 1 [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	0
Derivative Liability Fair Value Gross Liability	0
Natural Gas Commodity Contracts [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	45.5
Derivative Liability Fair Value Gross Liability	24.5
U.S. Bonds [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	21.6
Effects of netting, asset	0
U.S. Bonds [Member] | Fair Value, Inputs, Level 1 [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	21.6
U.S. Bonds [Member] | Fair Value, Inputs, Level 2 [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	0
Global Bonds [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	1.4
Effects of netting, asset	0
Global Bonds [Member] | Fair Value, Inputs, Level 1 [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	1.4
Global Bonds [Member] | Fair Value, Inputs, Level 2 [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	0
Interest Rate Swap [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	22.7
Effects of netting, asset	0
Derivative Liability Fair Value Gross Liability	2
Effects of netting, liability	0
Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	0
Derivative Liability Fair Value Gross Liability	0
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	22.7
Derivative Liability Fair Value Gross Liability	2
Spire Missouri [Member]
Derivative Asset Fair Value Gross Asset	22	$ 20.4	$ 19.5
Effects of netting, asset	(4.7)	(6.4)	(0.6)
Derivative Liability Fair Value Gross Liability	0		0
Effects of netting, liability	(61.1)		(35.9)
Spire Missouri [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative Asset Fair Value Gross Asset	26.7	26.7	20.1
Derivative Liability Fair Value Gross Liability	60.7		35.9
Spire Missouri [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative Asset Fair Value Gross Asset	0	0.1	0
Derivative Liability Fair Value Gross Liability	0.4		0
Spire Missouri [Member] | U S Stock And Bond Mutual Funds [Member]
Derivative Asset Fair Value Gross Asset	22	20.4	19.5
Effects of netting, asset	0	0	0
Derivative Liability Fair Value Gross Liability			0
Effects of netting, liability			(35.7)
Spire Missouri [Member] | U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative Asset Fair Value Gross Asset	22	20.4	19.5
Derivative Liability Fair Value Gross Liability			35.7
Spire Missouri [Member] | U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative Asset Fair Value Gross Asset	0	0	0
Derivative Liability Fair Value Gross Liability			0
Spire Missouri [Member] | N Y M E X I C E Natural Gas Contracts [Member]
Derivative Asset Fair Value Gross Asset	0	0	0
Effects of netting, asset	(4.7)	(6.3)	(0.4)
Derivative Liability Fair Value Gross Liability	0	6.8
Effects of netting, liability	(60.7)	(44)
Spire Missouri [Member] | N Y M E X I C E Natural Gas Contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative Asset Fair Value Gross Asset	4.7	6.3	0.4
Derivative Liability Fair Value Gross Liability	60.7	50.8
Spire Missouri [Member] | N Y M E X I C E Natural Gas Contracts [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative Asset Fair Value Gross Asset	0	0	0
Derivative Liability Fair Value Gross Liability	0	0
Spire Missouri [Member] | Gasoline And Heating Oil Contracts [Member]
Derivative Asset Fair Value Gross Asset		0	0
Effects of netting, asset		(0.1)	(0.2)
Derivative Liability Fair Value Gross Liability	0		0
Effects of netting, liability	(0.4)		(0.2)
Spire Missouri [Member] | Gasoline And Heating Oil Contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative Asset Fair Value Gross Asset		0	0.2
Derivative Liability Fair Value Gross Liability	0		0.2
Spire Missouri [Member] | Gasoline And Heating Oil Contracts [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative Asset Fair Value Gross Asset		$ 0.1	0
Derivative Liability Fair Value Gross Liability	0.4		0
Spire Alabama Inc [Member]
Derivative Asset Fair Value Gross Asset	135.3		188.9
Effects of netting, asset	(20.1)		(65.8)
Derivative Liability Fair Value Gross Liability	30.8		58.7
Effects of netting, liability	(69.4)		(107.5)
Spire Alabama Inc [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative Asset Fair Value Gross Asset	74.4		100.4
Derivative Liability Fair Value Gross Liability	72.6		94.3
Spire Alabama Inc [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative Asset Fair Value Gross Asset	81		154.3
Derivative Liability Fair Value Gross Liability	27.6		71.9
Spire Alabama Inc [Member] | U S Stock And Bond Mutual Funds [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	20.4		19.5
Effects of netting, asset	0		0
Spire Alabama Inc [Member] | U S Stock And Bond Mutual Funds [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset			0
Effects of netting, asset			(52)
Spire Alabama Inc [Member] | U S Stock And Bond Mutual Funds [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	37.6		28.3
Effects of netting, asset	0		0
Spire Alabama Inc [Member] | U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	20.4		19.5
Spire Alabama Inc [Member] | U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset			52
Spire Alabama Inc [Member] | U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	37.6		28.3
Spire Alabama Inc [Member] | U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	0		0
Spire Alabama Inc [Member] | U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset			0
Spire Alabama Inc [Member] | U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 2 [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	0		0
Spire Alabama Inc [Member] | N Y M E X I C E Natural Gas Contracts [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	0		0
Effects of netting, asset	(6.3)		(0.4)
Derivative Liability Fair Value Gross Liability	6.8		0
Effects of netting, liability	(44)		(35.7)
Spire Alabama Inc [Member] | N Y M E X I C E Natural Gas Contracts [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	0
Effects of netting, asset	(10.1)
Derivative Liability Fair Value Gross Liability	0		0
Effects of netting, liability	(21.8)		(58.4)
Spire Alabama Inc [Member] | N Y M E X I C E Natural Gas Contracts [Member] | Fair Value, Inputs, Level 1 [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	6.3		0.4
Derivative Liability Fair Value Gross Liability	50.8		35.7
Spire Alabama Inc [Member] | N Y M E X I C E Natural Gas Contracts [Member] | Fair Value, Inputs, Level 1 [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	10.1
Derivative Liability Fair Value Gross Liability	21.8		58.4
Spire Alabama Inc [Member] | N Y M E X I C E Natural Gas Contracts [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	0		0
Derivative Liability Fair Value Gross Liability	0		0
Spire Alabama Inc [Member] | N Y M E X I C E Natural Gas Contracts [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	0
Derivative Liability Fair Value Gross Liability	0		0
Spire Alabama Inc [Member] | Gasoline And Heating Oil Contracts [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	0		0
Effects of netting, asset	(0.1)		(0.2)
Derivative Liability Fair Value Gross Liability			0
Effects of netting, liability			(0.2)
Spire Alabama Inc [Member] | Gasoline And Heating Oil Contracts [Member] | Fair Value, Inputs, Level 1 [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	0		0.2
Derivative Liability Fair Value Gross Liability			0.2
Spire Alabama Inc [Member] | Gasoline And Heating Oil Contracts [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	0.1		0
Derivative Liability Fair Value Gross Liability			0
Spire Alabama Inc [Member] | Natural Gas Commodity Contracts [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	33.1		79.7
Effects of netting, asset	(3.6)		(13.2)
Derivative Liability Fair Value Gross Liability	24		57.9
Effects of netting, liability	(3.6)		(13.2)
Spire Alabama Inc [Member] | Natural Gas Commodity Contracts [Member] | Fair Value, Inputs, Level 1 [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	0		0
Derivative Liability Fair Value Gross Liability	0		0
Spire Alabama Inc [Member] | Natural Gas Commodity Contracts [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	36.7		92.9
Derivative Liability Fair Value Gross Liability	27.6		71.1
Spire Alabama Inc [Member] | Interest Rate Swap [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	44.2		61.4	[1]
Effects of netting, asset	0		0
Derivative Liability Fair Value Gross Liability			0.8
Effects of netting, liability			0
Spire Alabama Inc [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	0		0	[1]
Derivative Liability Fair Value Gross Liability			0
Spire Alabama Inc [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member] | Other Segments [Member]
Derivative Asset Fair Value Gross Asset	$ 44.2		61.4	[1]
Derivative Liability Fair Value Gross Liability			$ 0.8
[1]Subsequent to the issuance of its consolidated financial statements for the quarter ended December 31, 2022, during the fourth quarter of fiscal 2023, the Company iden??fied an error in the fair value level presenta??on for certain line items in the Fair Value Measurements table. The presenta??on has been corrected to reflect the impacted line items in Level 2 rather than Level 1 as of December 31, 2022. This immaterial correc??on did not impact the reported fair values or the consolidated financial statements.

Note 9 - Pension Plans and Ot_3

Note 9 - Pension Plans and Other Postretirement Benefits (Details Textual) - USD ($) $ in Thousands				3 Months Ended
	Dec. 26, 2022	Dec. 23, 2021	Dec. 22, 2021	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Settlement				$ 0
Regulatory Asset, Total				1,523,300	$ 1,489,800	$ 1,597,500
Regulatory Liability				494,300	348,600	479,700
Pension Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement				0	(8,600)
Spire Alabama Inc [Member]
Regulatory Asset, Total				643,600	627,700	648,500
Regulatory Liability				20,700	22,200	21,200
Spire Alabama Inc [Member] | Pension Plan [Member]
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Settlement				27,500
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement				0	(8,600)
Defined Benefit Plan, Plan Assets, Contributions by Employer				2,000
Anticipated Contributions to Pension Plans Qualified Trusts				14,400
Spire Alabama Inc [Member] | Two Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement				$ (8,600)
Spire Alabama Inc [Member] | Pension Plan One [Member]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate				5.60%			5.70%
Defined Benefit Plan, Benefit Obligation, Settlement Losses Amortized Over Remaining Actuarial Life (Year)				13 years 4 months 24 days
Spire Alabama Inc [Member] | Pension Plan Two [Member]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate							5.65%
Defined Benefit Plan, Benefit Obligation, Settlement Losses Amortized Over Remaining Actuarial Life (Year)				12 years 4 months 24 days
Spire Alabama Inc [Member] | Other Postretirement Benefits Plan [Member]
Anticipated Contributions to Pension Plans Qualified Trusts				$ 0
Spire Missouri [Member]
Regulatory Asset, Total				843,700	825,900	910,700
Regulatory Liability				404,500	$ 259,000	$ 389,400
Spire Missouri [Member] | Pension Costs [Member] | Missouri West [Member]
Regulatory Asset, Total		$ 4,400	$ 5,500
Spire Missouri [Member] | Pension Costs [Member] | Missouri East [Member]
Regulatory Asset, Total	$ 29,900	32,400	29,000
Spire Missouri [Member] | Pension and Other Postretirement Plans Costs [Member] | Missouri West [Member]
Regulatory Liabilities For Which No Return On Investment During Recovery Period Is Provided	800	$ 1,100	$ 3,300
Remaining Recovery Period of Regulatory Liabilities for which No Return on Investment During Recovery Period is Provided (Year)		8 years	8 years
Spire Missouri [Member] | Pension and Other Postretirement Plans Costs [Member] | Missouri East [Member]
Regulatory Assets for Which No Return on Investment During Recovery Period Is Provided	6,900	$ 11,000	$ 21,600
Remaining Recovery Period of Regulatory Assets for which No Return on Investment During Recovery Period is Provided (Year)			8 years
Additional Remaining Recovery Period of Regulatory Assets for Which No Return on Investment During Recovery Period Is Provided (Year)		8 years
Spire Missouri [Member] | Pension Plan [Member]
Anticipated Contributions to Pension Plans Qualified Trusts				16,600
Spire Missouri [Member] | Pension Plan [Member] | Qualified Plan [Member]
Defined Benefit Plan, Plan Assets, Contributions by Employer				5,000
Spire Missouri [Member] | Pension Plan [Member] | Nonqualified Plan [Member]
Defined Benefit Plan, Plan Assets, Contributions by Employer				0
Spire Missouri [Member] | Other Postretirement Benefits Plan [Member]
Anticipated Contributions to Pension Plans Qualified Trusts				$ 0
Postretirement Benefit Plans, Recovery in Rates Base Allowance		$ 8,600
Spire Missouri [Member] | Other Postretirement Benefits Plan [Member] | Missouri West [Member]
Regulatory Liability	100
Spire Missouri [Member] | Other Postretirement Benefits Plan [Member] | Missouri East [Member]
Regulatory Liability	$ 900

Note 9 - Pension Plans and Ot_4

Note 9 - Pension Plans and Other Postretirement Benefits - Net Pension Costs (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Pension Plan [Member]
Service cost – benefits earned during the period	$ 4	$ 4.1
Interest cost on projected benefit obligation	6.8	6.4
Expected return on plan assets	(6.3)	(6.4)
Amortization of prior service credit	(1.1)	(1.1)
Amortization of actuarial loss	1.6	1.6
Loss on lump-sum settlements	0	8.6
Subtotal	5	13.2
Regulatory adjustment	8.7	1.8
Net pension cost	13.7	15
Pension Plan [Member] | Spire Missouri [Member]
Service cost – benefits earned during the period	2.6	2.8
Interest cost on projected benefit obligation	4.8	4.5
Expected return on plan assets	(4.3)	(4.5)
Amortization of prior service credit	(0.5)	(0.5)
Amortization of actuarial loss	1.5	1.5
Subtotal	4.1	3.8
Regulatory adjustment	6.3	8.1
Net pension cost	10.4	11.9
Pension Plan [Member] | Spire Alabama Inc [Member]
Service cost – benefits earned during the period	1.2	1.1
Interest cost on projected benefit obligation	1.3	1.3
Expected return on plan assets	(1.2)	(1.1)
Amortization of prior service credit	(0.6)	(0.6)
Amortization of actuarial loss	0.2	0.1
Loss on lump-sum settlements	0	8.6
Subtotal	0.9	9.4
Regulatory adjustment	2.2	(6.5)
Net pension cost	3.1	2.9
Other Postretirement Benefits Plan [Member]
Service cost – benefits earned during the period	1.1	1.2
Interest cost on projected benefit obligation	2.1	2.1
Expected return on plan assets	(4)	(3.9)
Amortization of prior service credit	0.1	0.1
Amortization of actuarial loss	(1)	(1)
Subtotal	(1.7)	(1.5)
Regulatory adjustment	0.2	0.1
Net pension cost	(1.5)	(1.4)
Other Postretirement Benefits Plan [Member] | Spire Missouri [Member]
Service cost – benefits earned during the period	0.9	1
Interest cost on projected benefit obligation	1.6	1.6
Expected return on plan assets	(2.7)	(2.6)
Amortization of prior service credit	0.2	0.2
Amortization of actuarial loss	(0.9)	(0.8)
Subtotal	(0.9)	(0.6)
Regulatory adjustment	0.6	0.6
Net pension cost	(0.3)	0
Other Postretirement Benefits Plan [Member] | Spire Alabama Inc [Member]
Service cost – benefits earned during the period	0.2	0.2
Interest cost on projected benefit obligation	0.5	0.4
Expected return on plan assets	(1.3)	(1.2)
Amortization of prior service credit	(0.1)	(0.1)
Amortization of actuarial loss	0	(0.1)
Subtotal	(0.7)	(0.8)
Regulatory adjustment	(0.4)	(0.5)
Net pension cost	$ (1.1)	$ (1.3)

Note 10 - Information by Oper_3

Note 10 - Information by Operating Segment (Details Textual)	3 Months Ended	12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023
Number of Reportable Segments	3	3

Note 10 - Information by Oper_4

Note 10 - Information by Operating Segment - Segment Information by Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Revenues from external customers	$ 756.6	$ 814
Intersegment revenues	0	0
Operating Revenues	756.6	814
Depreciation and amortization	67	62.1
Interest Expense, Net	50.6	43.6
Income Tax Expense	21	21.6
Net economic earnings (loss)	82.7	85.1
Capital expenditures	226.5	154.8
Consolidation, Eliminations [Member]
Revenues from external customers	0	0
Intersegment revenues	(13.9)	(12.3)
Operating Revenues	(13.9)	(12.3)
Depreciation and amortization	0	0
Interest Expense, Net	(14.2)	(9.9)
Income Tax Expense	0	0
Net economic earnings (loss)	0	0
Capital expenditures	(0.4)	0
Gas Utility [Member] | Operating Segments [Member]
Revenues from external customers	715.2	733
Intersegment revenues	0	0
Operating Revenues	715.2	733
Depreciation and amortization	64.2	59.7
Interest Expense, Net	39	32.1
Income Tax Expense	15.7	12.4
Net economic earnings (loss)	75.8	62.9
Capital expenditures	174.9	146.3
Gas Marketing [Member] | Operating Segments [Member]
Revenues from external customers	36.3	74.1
Intersegment revenues	0	0
Operating Revenues	36.3	74.1
Depreciation and amortization	0.4	0.3
Interest Expense, Net	0	0
Income Tax Expense	3.8	10.5
Net economic earnings (loss)	7.2	25.7
Capital expenditures	0	0.2
Midstream [Member] | Operating Segments [Member]
Revenues from external customers	5	6.8
Intersegment revenues	9.9	8.4
Operating Revenues	14.9	15.2
Depreciation and amortization	2.3	1.9
Interest Expense, Net	1.8	1.9
Income Tax Expense	0.6	1.4
Net economic earnings (loss)	2.4	3.8
Capital expenditures	52	7.7
Other Segments [Member]
Depreciation and amortization	0.1	0.2
Interest Expense, Net	24	19.5
Income Tax Expense	0.9	(2.7)
Other Segments [Member] | Consolidation, Eliminations [Member]
Revenues from external customers	0.1	0.1
Intersegment revenues	4	3.9
Operating Revenues	4.1	4
Net economic earnings (loss)	(2.7)	(7.3)
Capital expenditures	$ 0	$ 0.6

Note 10 - Information by Oper_5

Note 10 - Information by Operating Segment - Net Economic Earnings to Net Income (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Net Income	$ 85.1	$ 91
Fair value and timing adjustments	(5.2)	(7.8)
Acquisition activities	1.9	0
Income tax adjustments	0.9	1.9
Net Economic Earnings	$ 82.7	$ 85.1

Note 10 - Information by Oper_6

Note 10 - Information by Operating Segment - Total Assets by Segment (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Total Assets	$ 10,631.7	$ 10,313.6	$ 10,327.7
Operating Segments [Member] | Gas Utility [Member]
Total Assets	8,736.7	8,486.7	8,355.1
Operating Segments [Member] | Gas Marketing [Member]
Total Assets	207	332	492.4
Operating Segments [Member] | Midstream [Member]
Total Assets	633.9	574.3	466.6
Operating Segments [Member] | Other Segments [Member]
Total Assets	2,755.1	2,533.3	2,882.8
Consolidation, Eliminations [Member]
Total Assets	$ (1,701)	$ (1,612.7)	$ (1,869.2)

Note 11 - Commitments and Con_2

Note 11 - Commitments and Contingencies (Details Textual) $ in Millions	3 Months Ended
	Dec. 31, 2023 USD ($)
Long-Term Purchase Commitment, Amount	$ 1,900.3
Capital Committed to Contribute to Partnership	10
Remaining Unfunded Capital Commitment	4.9
Spire Missouri [Member]
Long-Term Purchase Commitment, Amount	1,331.4
Spire Alabama Inc [Member]
Long-Term Purchase Commitment, Amount	$ 403.5