Spire Alabama 10-Q 31 Jul 24 2024 Q2 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Jun. 30, 2024	Jul. 28, 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	Q3
Document Fiscal Year Focus	2024
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2024
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		57,750,474
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	Q2
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	Q2
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
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		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Operating Revenues	$ 414.1	$ 418.5	$ 2,299.2	$ 2,355.9
Operating Expenses:
Natural gas	140.9	169.8	1,048.7	1,175.5
Operation and maintenance	126.7	125.5	395.2	389.7
Depreciation and amortization	71.4	64.3	207.3	189
Taxes, other than income taxes	44.4	46.9	179.5	179.2
Total Operating Expenses	383.4	406.5	1,830.7	1,933.4
Operating Income	30.7	12	468.5	422.5
Interest Expense, Net	48.8	46.7	151.6	137.5
Other Income, Net	2.4	6.3	27.2	19.3
(Loss) Income Before Income Taxes	(15.7)	(28.4)	344.1	304.3
Income Tax (Benefit) Expense	(3.1)	(6.8)	67.3	55.7
Net (Loss) Income	(12.6)	(21.6)	276.8	248.6
Provision for preferred dividends	3.7	3.7	11.1	11.1
(Loss) income allocated to participating securities	0	(0.1)	0.4	0.4
Net (Loss) Income Available to Common Shareholders	$ (16.3)	$ (25.2)	$ 265.3	$ 237.1
Weighted Average Number of Common Shares Outstanding:
Basic (in shares)	57.7	52.5	55.6	52.5
Diluted (in shares)	57.7	52.5	55.7	52.6
Basic (Loss) Earnings Per Common Share (in dollars per share)	$ (0.28)	$ (0.48)	$ 4.77	$ 4.52
Diluted (Loss) Earnings Per Common Share (in dollars per share)	$ (0.28)	$ (0.48)	$ 4.76	$ 4.51
Operating Revenues	$ 414.1	$ 418.5	$ 2,299.2	$ 2,355.9
Spire Alabama Inc [Member]
Operating Revenues	103.5	113.1	505.1	483.8
Operating Expenses:
Natural gas	31.8	42.7	173.2	173.9
Operation and maintenance	33.7	33.4	103.3	103
Depreciation and amortization	18.4	17.5	54.5	51.5
Taxes, other than income taxes	8.3	9.3	36.4	36
Total Operating Expenses	92.2	102.9	367.4	364.4
Operating Income	11.3	10.2	137.7	119.4
Interest Expense, Net	7.9	8.7	25.5	26
Other Income, Net	0.6	0.4	1.3	1.1
(Loss) Income Before Income Taxes	4	1.9	113.5	94.5
Income Tax (Benefit) Expense	1.1	0.6	28.8	24
Net (Loss) Income	2.9	1.3	84.7	70.5
Weighted Average Number of Common Shares Outstanding:
Operating Revenues	$ 103.5	$ 113.1	$ 505.1	$ 483.8

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Jun. 30, 2024		Jun. 30, 2023	Jun. 30, 2024		Jun. 30, 2023
Net income	$ (12.6)		$ (21.6)	$ 276.8		$ 248.6
Other Comprehensive Income (Loss), Before Tax:
Net hedging gain (loss) arising during the period	4.3		7.6	(2)		(2.2)
Amounts reclassified into regulatory liabilities	0		0	0		(17.5)
Amounts reclassified into net income	(1.7)		(0.8)	(11.3)		(1.6)
Net gain (loss) on cash flow hedging derivative instruments	2.6		6.8	(13.3)		(21.3)
Net gain on defined benefit pension and other postretirement plans	1		0	1.1		0.2
Net unrealized gain on available for sale securities	0		0.1	0.1		0.1
Other Comprehensive Income (Loss), Before Tax	3.6		6.9	(12.1)		(21)
Income Tax Expense (Benefit) Related to Items of Other Comprehensive Income (Loss)	0.6		1.6	(3.1)		(5)
Other Comprehensive Income (Loss), Net of Tax	3		5.3	(9)		(16)
Comprehensive (Loss) Income	(9.6)		(16.3)	267.8		232.6
Operating Revenues	414.1		418.5	2,299.2		2,355.9
Operating Expenses:
Natural gas	140.9		169.8	1,048.7		1,175.5
Operation and maintenance	126.7		125.5	395.2		389.7
Depreciation and amortization	71.4		64.3	207.3		189
Taxes, other than income taxes	44.4		46.9	179.5		179.2
Total Operating Expenses	383.4		406.5	1,830.7		1,933.4
Operating Income	30.7		12	468.5		422.5
Interest Expense, Net	48.8		46.7	151.6		137.5
Other Income, Net	2.4		6.3	27.2		19.3
(Loss) Income Before Income Taxes	(15.7)		(28.4)	344.1		304.3
Income Tax (Benefit) Expense	(3.1)		(6.8)	67.3		55.7
Net (Loss) Income	(12.6)		(21.6)	276.8		248.6
Other Comprehensive Income, Net of Tax	3		5.3	(9)		(16)
Comprehensive (Loss) Income	(9.6)		(16.3)	267.8		232.6
Spire Missouri [Member]
Net income	(16.8)		(13.8)	145.4	[1]	145.6
Other Comprehensive Income (Loss), Before Tax:
Other Comprehensive Income (Loss), Net of Tax	0.9	[1]	0	1	[1]	0.2
Comprehensive (Loss) Income	(15.9)		(13.8)	146.4		145.8
Operating Revenues	248.8		253.8	1,550.7		1,586
Operating Expenses:
Natural gas	94.5		105.5	830.8		887.9
Operation and maintenance	72.8		71.1	226.3		225.6
Depreciation and amortization	44		40	129.2		117.8
Taxes, other than income taxes	32.7		34.4	131		132
Total Operating Expenses	244		251	1,317.3		1,363.3
Operating Income	4.8		2.8	233.4		222.7
Interest Expense, Net	25.3		24.9	80.9		71.5
Other Income, Net	1.8		4.7	14.7		15.6
(Loss) Income Before Income Taxes	(18.7)		(17.4)	167.2		166.8
Income Tax (Benefit) Expense	(1.9)		(3.6)	21.8		21.2
Net (Loss) Income	(16.8)		(13.8)	145.4	[1]	145.6
Other Comprehensive Income, Net of Tax	0.9	[1]	0	1	[1]	0.2
Comprehensive (Loss) Income	$ (15.9)		$ (13.8)	$ 146.4		$ 145.8
[1]Accumulated other comprehensive income (loss)

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Millions	Jun. 30, 2024		Sep. 30, 2023		Jun. 30, 2023
ASSETS
Utility Plant	$ 8,612.9		$ 8,210.1		$ 8,016.7
Less: Accumulated depreciation and amortization	2,510.4		2,431.2		2,382.9
Net Utility Plant	6,102.5		5,778.9		5,633.8
Non-utility Property (net of accumulated depreciation and amortization of $90.1, $71.1 and $65.7 at June 30, 2024, September 30, 2023, and June 30, 2023, respectively)	917.9		628.5		582.7
Other Investments	112.1		102.6		102.5
Total Other Property and Investments	1,030		731.1		685.2
Other Property and Investments	1,030		731.1		685.2
Current Assets:
Cash and cash equivalents	7.4		5.6		5.3
Utility	238.4		192.4		245.9
Other	113.4		128.6		127.4
Allowance for credit losses	(33.2)		(32.5)		(34.7)
Delayed customer billings	26.8		22		58.6
Accounts receivable:
Utility	238.4		192.4		245.9
Other	113.4		128.6		127.4
Allowance for credit losses	(33.2)		(32.5)		(34.7)
Delayed customer billings	26.8		22		58.6
Inventories:
Natural gas	175		223.7		184.9
Propane gas	8.6		8.6		8.6
Materials and supplies	46.5		47.2		49.6
Regulatory assets	89.8		348.3		93.3
Prepayments	59.3		48.2		55.1
Other current assets	93.8		84.8		67.2
Total Current Assets	825.8		1,076.9		861.2
Deferred Charges and Other Assets:
Goodwill	1,171.6		1,171.6		1,171.6
Regulatory assets	1,282.8		1,249.2		1,421.2
Other	298.2		305.9		264.5
Total Deferred Charges and Other Assets	2,752.6		2,726.7		2,857.3
Total Assets	10,710.9		10,313.6		10,037.5
Capitalization:
Preferred stock ($25.00 par value per share; 10.0 million depositary shares authorized, issued and outstanding at June 30, 2024, September 30, 2023, and June 30, 2023)	242		242		242
Common stock (par value $1.00 per share; 70.0 million shares authorized; 57.7 million, 53.2 million, and 52.6 million shares issued and outstanding at June 30, 2024, September 30, 2023, and June 30, 2023, respectively)	57.7		53.2		52.6
Paid-in capital	1,901.5		1,616.5		1,578.3
Retained earnings	1,093.4		958		1,028.4
Accumulated other comprehensive income	38.6		47.6		31.2
Total Shareholders' Equity	3,333.2		2,917.3		2,932.5
Temporary equity	8.6		16.5		17.7
Long-term debt (less current portion)	3,422.3		3,554		3,553.3
Total Capitalization	6,764.1		6,487.8		6,503.5
Current Liabilities:
Current portion of long-term debt	307		156.6		406.6
Notes payable	771		955.5		557.6
Accounts payable	205.2		253.1		196.3
Advance customer billings	17.1		20.9		7.6
Wages and compensation accrued	41.5		47		35.9
Customer deposits	29.5		27.7		27.7
Taxes accrued	90.8		104.1		88.5
Regulatory liabilities	37.9		7.3		5.5
Other current liabilities	209.8		183.2		204.7
Total Current Liabilities	1,709.8		1,755.4		1,530.4
Deferred Credits and Other Liabilities:
Deferred income taxes	819.6		743.7		735.9
Pension and postretirement benefit costs	128.5		137.3		154.7
Asset retirement obligations	596		577.4		538.1
Regulatory liabilities	547.5		472.4		428.1
Other noncurrent liabilities	145.4		139.6		146.8
Total Deferred Credits and Other Liabilities	2,237		2,070.4		2,003.6
Commitments and Contingencies (Note 11)
Total Capitalization and Liabilities	10,710.9		10,313.6		10,037.5
Spire Missouri [Member]
ASSETS
Utility Plant	5,296.6		4,964.9		4,831.2
Less: Accumulated depreciation and amortization	1,073.5		1,043.2		1,037.6
Net Utility Plant	4,223.1		3,921.7		3,793.6
Total Other Property and Investments	69.4		65.7		67.7
Other Property and Investments	69.4		65.7		67.7
Current Assets:
Cash and cash equivalents	1.3		0.8		0
Other	18.4		21.1		23
Allowance for credit losses	(26.6)		(26.2)		(28.7)
Delayed customer billings	24.5		17.9		57
Accounts receivable:
Other	18.4		21.1		23
Allowance for credit losses	(26.6)		(26.2)		(28.7)
Delayed customer billings	24.5		17.9		57
Inventories:
Natural gas	103.7		132.8		98.5
Propane gas	8.6		8.6		8.6
Materials and supplies	24.1		24.2		25.1
Regulatory assets	63		293.1		35
Prepayments	36.6		26.7		34.5
Total Current Assets	431.5		642.9		446.9
Deferred Charges and Other Assets:
Goodwill	210.2		210.2		210.2
Regulatory assets	634.1		617.6		819.1
Other	144.8		147.4		108.4
Total Deferred Charges and Other Assets	989.1		975.2		1,137.7
Total Assets	5,713.1		5,605.5		5,445.9
Capitalization:
Retained earnings	1,137.8		992.4		1,034
Accumulated other comprehensive income	(1.5)		(2.5)		(2.5)
Total Shareholders' Equity	1,991.2	[1]	1,844.8	[1]	1,847.7
Long-term debt (less current portion)	1,486.6		1,785.4		1,785.1
Total Capitalization	3,477.8		3,630.2		3,632.8
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	8.8		11		0
Wages and compensation accrued	18		23.6		18.3
Customer deposits	5.9		5.8		5.8
Taxes accrued	49.5		60.3		49.3
Other current liabilities	46.6		48.7		43.6
Total Current Liabilities	925.7		786.3		671.7
Deferred Credits and Other Liabilities:
Deferred income taxes	567.7		531.8		533.7
Pension and postretirement benefit costs	100.1		103.3		96.4
Asset retirement obligations	114.5		111.1		113.9
Regulatory liabilities	465.7		389.4		346.1
Other noncurrent liabilities	61.6		53.4		51.3
Total Deferred Credits and Other Liabilities	1,309.6		1,189		1,141.4
Total Capitalization and Liabilities	5,713.1		5,605.5		5,445.9
Spire Missouri [Member] | Nonrelated Party [Member]
Current Assets:
Utility	176.3		142.6		186.8
Accounts receivable:
Utility	176.3		142.6		186.8
Current Liabilities:
Accounts payable	68.2		85.8		63.3
Spire Missouri [Member] | Related Party [Member]
Current Assets:
Utility	1.6		1.3		7.1
Accounts receivable:
Utility	1.6		1.3		7.1
Current Liabilities:
Notes payable	418.3		540.6		228.1
Accounts payable	10.4		10.5		13.3
Spire Alabama Inc [Member]
ASSETS
Utility Plant	2,929.1		2,862.6		2,803.8
Less: Accumulated depreciation and amortization	1,324.9		1,273		1,224.5
Net Utility Plant	1,604.2		1,589.6		1,579.3
Current Assets:
Cash and cash equivalents	2.3		1.2		0.5
Other	5.3		6.6		6.4
Allowance for credit losses	(5.7)		(5.7)		(5.3)
Delayed customer billings	2		3.6		1.4
Accounts receivable:
Other	5.3		6.6		6.4
Allowance for credit losses	(5.7)		(5.7)		(5.3)
Delayed customer billings	2		3.6		1.4
Inventories:
Natural gas	34.4		52.4		51.9
Materials and supplies	18.5		19.1		20.6
Regulatory assets	14.7		41.6		43.9
Prepayments	9.1		6.4		8.8
Total Current Assets	133.3		168.6		181.9
Deferred Charges and Other Assets:
Regulatory assets	626		606.9		576.7
Other	84.8		84.2		82
Total Deferred Charges and Other Assets	710.8		691.1		658.7
Total Assets	2,448.3		2,449.3		2,419.9
Capitalization:
Retained earnings	683.9		642.1		646.6
Total Shareholders' Equity	963.3		928		933.5
Long-term debt (less current portion)	746.2		745.9		745.8
Total Capitalization	1,709.5		1,673.9		1,679.3
Paid-in capital and common stock	279.4		285.9		286.9
Current Liabilities:
Advance customer billings	6.5		8.1		5.9
Wages and compensation accrued	5.2		6.6		4.9
Customer deposits	20.5		19.3		19.3
Taxes accrued	32.7		34.5		31.6
Regulatory liabilities	32.2		0		0
Other current liabilities	12.2		14.7		12.2
Total Current Liabilities	167.3		240.3		217.4
Deferred Credits and Other Liabilities:
Deferred income taxes	37.8		9.1		12.8
Pension and postretirement benefit costs	21.2		27.2		52.3
Asset retirement obligations	465.6		451		411
Regulatory liabilities	19.6		21.2		20.8
Other noncurrent liabilities	27.3		26.6		26.3
Total Deferred Credits and Other Liabilities	571.5		535.1		523.2
Total Capitalization and Liabilities	2,448.3		2,449.3		2,419.9
Spire Alabama Inc [Member] | Nonrelated Party [Member]
Current Assets:
Utility	52.2		42.2		50.1
Accounts receivable:
Utility	52.2		42.2		50.1
Current Liabilities:
Accounts payable	30.2		28.4		28.2
Spire Alabama Inc [Member] | Related Party [Member]
Current Assets:
Utility	0.5		1.2		3.6
Accounts receivable:
Utility	0.5		1.2		3.6
Current Liabilities:
Notes payable	23		124.1		108.1
Accounts payable	$ 4.8		$ 4.6		$ 7.2
[1]Accumulated other comprehensive income (loss)

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Millions	Jun. 30, 2024	Sep. 30, 2023	Jun. 30, 2023
Non-utility property, accumulated depreciation and amortization	$ 90.1	$ 71.1	$ 65.7
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)	57,700,000	53,200,000	52,600,000
Common Stock, shares outstanding (in shares)	57,700,000	53,200,000	52,600,000
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	Spire Missouri [Member] Common Stock [Member]	Spire Missouri [Member] Additional Paid-in Capital [Member]	Spire Missouri [Member] Retained Earnings [Member]	Spire Missouri [Member] AOCI Attributable to Parent [Member]	Spire Missouri [Member]		Spire Alabama Inc [Member] Common Stock [Member]	Spire Alabama Inc [Member] Additional Paid-in Capital [Member]	Spire Alabama Inc [Member] Retained Earnings [Member]	Spire Alabama Inc [Member]	Common Stock [Member]	Preferred Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]		Total
Balance (in shares) at Sep. 30, 2022	25,325						1,972,052				52,494,543
Balance at Sep. 30, 2022	$ 0.1	$ 816.1	$ 931.9	$ (2.7)	$ 1,745.4		$ 0	$ 316.9	$ 589.1	$ 906	$ 52.5	$ 242	$ 1,571.3	$ 905.5	$ 47.2		$ 2,818.5
Net income	0	0	145.6	0	145.6		0	0	70.5	70.5	$ 0		0	248.6	0	[1]	248.6
Dividend reinvestment plan (in shares)											16,488
Dividend reinvestment plan											$ 0	0	1.1	0	0		1.1
Stock-based compensation costs											$ 0	0	4.3	0	0		4.3
Stock activity under stock-based compensation plans (in shares)											64,077
Stock activity under stock-based compensation plans											$ 0	0	0		0		0
Employees’ tax withholding for stock-based compensation (in shares)											(17,679)
Employees’ tax withholding for stock-based compensation											$ 0	0	(1.3)	0	0		(1.3)
Temporary equity adjustment to redemption value											0	0	0	(0.2)	0		(0.2)
Common stock	0	0	(43.5)	0	(43.5)		$ 0	0	(13)	(13)	0	0	0	(114.4)	0		(114.4)
Preferred stock											0	0	0	(11.1)	0		(11.1)
Other Comprehensive Income, Net of Tax	$ 0	0	0	0.2	0.2						$ 0	0	0	0	(16)		(16)
Common stock issued (in shares)											40,500
Common stock issued											$ 0.1	0	2.9	0	0		3
Balance (in shares) at Jun. 30, 2023	25,325						1,972,052				52,597,929
Balance at Jun. 30, 2023	$ 0.1	816.1	1,034	(2.5)	1,847.7		$ 0	286.9	646.6	933.5	$ 52.6	242	1,578.3	1,028.4	31.2	[1]	2,932.5
Return of capital to Spire							$ 0	(30)	0	(30)
Balance (in shares) at Mar. 31, 2023	25,325						1,972,052				52,593,433
Balance at Mar. 31, 2023	$ 0.1	816.1	1,061.3	(2.5)	1,875		$ 0	289.9	645.3	935.2	$ 52.6	242	1,576.5	1,089.5	25.9	[1]	2,986.5
Net income	0	0	(13.8)	0	(13.8)		$ 0	0	1.3	1.3	$ 0	0	0	(21.6)	0		(21.6)
Dividend reinvestment plan (in shares)											5,367
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)											(609)
Stock activity under stock-based compensation plans											$ 0	0	0		0		0
Employees’ tax withholding for stock-based compensation (in shares)											(262)
Employees’ tax withholding for stock-based compensation											$ 0	0	0	0	0	[1]	0
Temporary equity adjustment to redemption value											0		0	2.8	0	[1]	2.8
Common stock	$ 0	0	(13.5)	0	(13.5)						0		0	(38.6)	0	[1]	(38.6)
Preferred stock											0		0	(3.7)	0	[1]	(3.7)
Other Comprehensive Income, Net of Tax					0						$ 0	0	0	0	5.3		5.3
Balance (in shares) at Jun. 30, 2023	25,325						1,972,052				52,597,929
Balance at Jun. 30, 2023	$ 0.1	816.1	1,034	(2.5)	1,847.7		$ 0	286.9	646.6	933.5	$ 52.6	242	1,578.3	1,028.4	31.2	[1]	2,932.5
Return of capital to Spire							$ 0	(3)	0	(3)
Balance (in shares) at Sep. 30, 2023	25,855						1,972,052				53,170,224
Balance at Sep. 30, 2023	$ 0.1	854.8	992.4	(2.5)	1,844.8	[1]	$ 0	285.9	642.1	928	$ 53.2	242	1,616.5	958	47.6		2,917.3
Net income	0	0	145.4	0	145.4	[1]	0	0	84.7	84.7	$ 0	0	0	276.8	0		276.8
Dividend reinvestment plan (in shares)											19,811
Dividend reinvestment plan											$ 0	0	1.2	0	0		1.2
Stock-based compensation costs											$ 0	0	3.8	0	0		3.8
Stock activity under stock-based compensation plans (in shares)											89,834
Stock activity under stock-based compensation plans											$ 0.1		(0.1)				0
Employees’ tax withholding for stock-based compensation (in shares)											(24,662)
Employees’ tax withholding for stock-based compensation											$ 0	0	(1.5)	0	0		(1.5)
Temporary equity adjustment to redemption value											0	0	0	(1.1)	0		(1.1)
Common stock							$ 0	0	(42.9)	(42.9)	0	0	0	(129.2)	0		(129.2)
Preferred stock											0	0	0	(11.1)	0		(11.1)
Other Comprehensive Income, Net of Tax	$ 0	0	0	1	1	[1]					$ 0	0	0	0	(9)		(9)
Common stock issued (in shares)											4,490,282
Common stock issued											$ 4.4	0	281.6	0	0		286
Balance (in shares) at Jun. 30, 2024	25,855						1,972,052				57,745,489
Balance at Jun. 30, 2024	$ 0.1	854.8	1,137.8	(1.5)	1,991.2	[1]	$ 0	279.4	683.9	963.3	$ 57.7	242	1,901.5	1,093.4	38.6		3,333.2
Return of capital to Spire							$ 0	(6.5)	0	(6.5)
Balance (in shares) at Mar. 31, 2024	25,855						1,972,052				57,741,692
Balance at Mar. 31, 2024	$ 0.1	854.8	1,154.6	(2.4)	2,007.1	[1]	$ 0	279.4	687.5	966.9	$ 57.7	242	1,899.7	1,155.3	35.6		3,390.3
Net income	0	0	(16.8)	0	(16.8)		0	0	2.9	2.9	$ 0	0	0	(12.6)	0		(12.6)
Dividend reinvestment plan (in shares)											6,600
Dividend reinvestment plan											$ 0	0	0.4	0	0		0.4
Stock-based compensation costs											$ 0	0	1.4	0	0		1.4
Stock activity under stock-based compensation plans (in shares)											(2,682)
Stock activity under stock-based compensation plans																	0
Employees’ tax withholding for stock-based compensation (in shares)											(121)
Employees’ tax withholding for stock-based compensation											$ 0	0	0	0	0		0
Temporary equity adjustment to redemption value											0	0	0	0.3	0		0.3
Common stock							$ 0	0	(6.5)	(6.5)	0	0	0	(45.9)	0		(45.9)
Preferred stock											0	0	0	(3.7)	0		(3.7)
Other Comprehensive Income, Net of Tax	$ 0	0	0	0.9	0.9	[1]					$ 0	0	0	0	3		3
Balance (in shares) at Jun. 30, 2024	25,855						1,972,052				57,745,489
Balance at Jun. 30, 2024	$ 0.1	$ 854.8	$ 1,137.8	$ (1.5)	$ 1,991.2	[1]	$ 0	$ 279.4	$ 683.9	$ 963.3	$ 57.7	$ 242	$ 1,901.5	$ 1,093.4	$ 38.6		$ 3,333.2
[1]Accumulated other comprehensive income (loss)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Shareholders' Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Common stock, dividends per share declared (in dollars per share)	$ 0.755	$ 0.72	$ 2.265	$ 2.16
Preferred stock dividends per share declared (in dollars per share)	$ 0.36875	$ 0.36875	$ 1.10625	$ 1.10625

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Jun. 30, 2024		Jun. 30, 2023
Operating Activities:
Net income	$ 276.8		$ 248.6
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	207.3		189
Deferred income taxes and investment tax credits	66.4		55.7
Changes in assets and liabilities:
Accounts receivable	(28.5)		284.1
Inventories	49.5		179.3
Regulatory assets and liabilities	343.2		(18)
Accounts payable	(24.5)		(405.6)
Delayed/advance customer billings, net	(8.6)		(48.5)
Taxes accrued	(15.5)		(2.3)
Other assets and liabilities	(42.6)		(88.4)
Other	6		10.2
Net cash provided by operating activities	829.5		404.1
Delayed/advance customer billings	(8.6)		(48.5)
Investing Activities:
Capital expenditures	(631.5)		(483.3)
Business acquisitions, net of cash acquired	(175.9)		(37)
Other	5.4		3.9
Net cash used in investing activities	(802)		(516.4)
Financing Activities:
Issuance of long-term debt	175		755
Repayment of long-term debt	(156.6)		(31.2)
Repayment of short-term debt, net	(184.5)		(479.9)
Issuance of common stock	287.2		4
Dividends paid on common stock	(124.3)		(112.5)
Dividends paid on preferred stock	(11.1)		(11.1)
Other financing activities	(5.3)		(7.5)
Net cash (used in) provided by financing activities	(19.6)		116.8
Net Increase in Cash, Cash Equivalents, and Restricted Cash	7.9		4.5
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	25.8		20.5
Cash, Cash Equivalents, and Restricted Cash at End of Period	33.7		25
Supplemental disclosure of cash paid for:
Interest, net of amounts capitalized	(142.9)		(118.2)
Income taxes	(0.9)		(1.8)
Spire Missouri [Member]
Operating Activities:
Net income	145.4	[1]	145.6
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	129.2		117.8
Deferred income taxes and investment tax credits	21.5		21.2
Changes in assets and liabilities:
Accounts receivable	(30.7)		(33.3)
Inventories	29.2		113.7
Regulatory assets and liabilities	291.8		1.2
Accounts payable	(3.9)		(43.6)
Delayed/advance customer billings, net	(8.8)		(47.9)
Taxes accrued	(10.7)		(1.1)
Other assets and liabilities	(35.8)		(88.4)
Other	1.1		1.3
Net cash provided by operating activities	528.3		186.5
Delayed/advance customer billings	(8.8)		(47.9)
Investing Activities:
Capital expenditures	(409.9)		(324.8)
Other	4.4		2.9
Net cash used in investing activities	(405.5)		(321.9)
Financing Activities:
Issuance of long-term debt	0		400
Dividends paid on common stock	0		(43.5)
Other financing activities	0		(3.9)
Net cash (used in) provided by financing activities	(122.3)		135.4
Net Increase in Cash, Cash Equivalents, and Restricted Cash	0.5		0
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	0.8		0
Cash, Cash Equivalents, and Restricted Cash at End of Period	1.3		0
Repayments of borrowings from Spire, net	(122.3)		(217.2)
Repayments of borrowings from Spire, net	(122.3)		(217.2)
Supplemental disclosure of cash paid for:
Interest, net of amounts capitalized	(84.1)		(64.7)
Income taxes	(0.4)		0
Spire Alabama Inc [Member]
Operating Activities:
Net income	84.7		70.5
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	54.5		51.5
Deferred income taxes and investment tax credits	28.8		24
Changes in assets and liabilities:
Accounts receivable	(7.9)		16.6
Inventories	18.6		16.4
Regulatory assets and liabilities	50.8		(16.8)
Accounts payable	1.2		(39.9)
Delayed/advance customer billings, net	0.1		(0.6)
Taxes accrued	(1.8)		0.3
Other assets and liabilities	(6.6)		3.3
Other	0.3		0.3
Net cash provided by operating activities	222.7		125.6
Delayed/advance customer billings	0.1		(0.6)
Investing Activities:
Capital expenditures	(71.7)		(98.4)
Other	0.5		0.7
Net cash used in investing activities	(71.2)		(97.7)
Financing Activities:
Issuance of long-term debt	0		175
Dividends paid on common stock	(42.9)		(21)
Other financing activities	0		(1)
Net cash (used in) provided by financing activities	(150.4)		(29.8)
Net Increase in Cash, Cash Equivalents, and Restricted Cash	1.1		(1.9)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	1.2		2.4
Cash, Cash Equivalents, and Restricted Cash at End of Period	2.3		0.5
Repayments of borrowings from Spire, net	(101)		(152.8)
Repayments of borrowings from Spire, net	(101)		(152.8)
Return of capital to Spire	(6.5)		(30)
Supplemental disclosure of cash paid for:
Interest, net of amounts capitalized	(27.4)		(23.3)
Income taxes	$ 0		$ 0
[1]Accumulated other comprehensive income (loss)

Note 1 - Summary of Significant

Note 1 - Summary of Significant Accounting Policies	9 Months Ended
	Jun. 30, 2024
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 June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Spire Missouri Purchases of natural gas from Spire Marketing $ — $ 6.5 $ 10.6 $ 48.8 Transportation services received from Spire STL Pipeline 7.9 8.0 24.4 23.9 Transportation services received from Spire MoGas Pipeline 1.7 — 3.1 — Sales of natural gas to Spire Marketing 1.4 0.3 1.7 0.4 Natural gas storage services from Spire Storage Salt Plains LLC — — 0.7 — Spire Alabama Purchases of natural gas from Spire Marketing $ — $ 1.7 $ 3.4 $ 2.8 RESTRICTED CASH AND OTHER INVESTMENTS June 30, 2024 June 30, 2024 September 30, 2023 June 30, 2023 BUSINESS COMBINATIONS January 19, 2024, 75 805, Business Combinations not three nine June 30, 2024. ACCRUED CAPITAL EXPENDITURES June 30, September 30, June 30, 2024 2023 2023 Spire $ 81.6 $ 104.3 $ 62.2 Spire Missouri 43.5 56.5 33.4 Spire Alabama 5.5 4.6 4.5 ACCOUNTS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES not Spire Spire Missouri Spire Alabama Three Months Ended June 30, 2024 2023 2024 2023 2024 2023 Allowance at beginning of period $ 39.1 $ 40.6 $ 32.0 $ 34.5 $ 6.2 $ 5.3 Provision for expected credit losses 5.6 1.2 4.7 0.3 0.7 0.8 Write-offs, net of recoveries (11.5 ) (7.1 ) (10.1 ) (6.1 ) (1.2 ) (0.8 ) Allowance at end of period $ 33.2 $ 34.7 $ 26.6 $ 28.7 $ 5.7 $ 5.3 Nine Months Ended June 30, 2024 2023 2024 2023 2024 2023 Allowance at beginning of period $ 32.5 $ 31.9 $ 26.2 $ 24.9 $ 5.7 $ 6.3 Provision for expected credit losses 17.6 13.5 14.5 11.4 2.4 1.5 Write-offs, net of recoveries (16.9 ) (10.7 ) (14.1 ) (7.6 ) (2.4 ) (2.5 ) Allowance at end of period $ 33.2 $ 34.7 $ 26.6 $ 28.7 $ 5.7 $ 5.3

Note 2 - Revenue

Note 2 - Revenue	9 Months Ended
	Jun. 30, 2024
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 June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Spire Gas Utility: Residential $ 232.2 $ 238.1 $ 1,454.5 $ 1,486.3 Commercial and industrial 87.3 102.2 513.1 533.1 Transportation 30.3 29.0 99.7 93.2 Off-system and other incentive 9.6 8.2 29.0 21.9 Other customer revenue 6.5 5.1 20.2 13.8 Total revenue from contracts with customers 365.9 382.6 2,116.5 2,148.3 Changes in accrued revenue under alternative revenue programs 6.8 5.2 44.1 27.0 Total Gas Utility operating revenues 372.7 387.8 2,160.6 2,175.3 Gas Marketing 21.2 23.1 103.5 157.8 Midstream 32.5 17.4 68.9 49.1 Other 4.8 4.3 13.0 12.4 Total before eliminations 431.2 432.6 2,346.0 2,394.6 Intersegment eliminations (see Note 10, Information by Operating Segment) (17.1 ) (14.1 ) (46.8 ) (38.7 ) Total Operating Revenues $ 414.1 $ 418.5 $ 2,299.2 $ 2,355.9 Spire Missouri Residential $ 169.5 $ 171.7 $ 1,091.2 $ 1,142.3 Commercial and industrial 52.6 61.1 348.5 369.2 Transportation 7.5 7.1 26.6 26.1 Off-system and other incentive 7.0 6.0 23.4 15.6 Other customer revenue 4.2 3.8 11.7 10.1 Total revenue from contracts with customers 240.8 249.7 1,501.4 1,563.3 Changes in accrued revenue under alternative revenue programs 8.0 4.1 49.3 22.7 Total Operating Revenues $ 248.8 $ 253.8 $ 1,550.7 $ 1,586.0 Spire Alabama Residential $ 53.0 $ 56.7 $ 306.7 $ 288.1 Commercial and industrial 26.9 32.7 130.4 127.8 Transportation 20.3 18.9 65.1 59.0 Off-system and other incentive 2.6 2.2 5.6 6.3 Other customer revenue 0.9 0.8 2.5 2.7 Total revenue from contracts with customers 103.7 111.3 510.3 483.9 Changes in accrued revenue under alternative revenue programs (0.2 ) 1.8 (5.2 ) (0.1 ) Total Operating Revenues $ 103.5 $ 113.1 $ 505.1 $ 483.8 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 June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Spire $ 22.4 $ 26.0 $ 113.5 $ 116.6 Spire Missouri 16.3 18.9 82.8 86.6 Spire Alabama 5.3 6.1 26.3 25.5

Note 3 - Earnings Per Common Sh

Note 3 - Earnings Per Common Share	9 Months Ended
	Jun. 30, 2024
Notes to Financial Statements
Earnings Per Share [Text Block]	3. Three Months Ended June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Basic Earnings Per Common Share: Net (Loss) Income $ (12.6 ) $ (21.6 ) $ 276.8 $ 248.6 Less: Provision for preferred dividends 3.7 3.7 11.1 11.1 (Loss) Income allocated to participating securities — (0.1 ) 0.4 0.4 (Loss) Income Available to Common Shareholders $ (16.3 ) $ (25.2 ) $ 265.3 $ 237.1 Weighted Average Common Shares Outstanding (in millions) 57.7 52.5 55.6 52.5 Basic (Loss) Earnings Per Common Share $ (0.28 ) $ (0.48 ) $ 4.77 $ 4.52 Diluted Earnings Per Common Share: Net (Loss) Income $ (12.6 ) $ (21.6 ) $ 276.8 $ 248.6 Less: Provision for preferred dividends 3.7 3.7 11.1 11.1 (Loss) Income allocated to participating securities — (0.1 ) 0.4 0.4 (Loss) Income Available to Common Shareholders $ (16.3 ) $ (25.2 ) $ 265.3 $ 237.1 Weighted Average Common Shares Outstanding (in millions) 57.7 52.5 55.6 52.5 Dilutive Effect of forward sales of common stock, restricted stock and restricted stock units (in millions)* — — 0.1 0.1 Weighted Average Diluted Common Shares (in millions) 57.7 52.5 55.7 52.6 Diluted (Loss) Earnings Per Common Share $ (0.28 ) $ (0.48 ) $ 4.76 $ 4.51 * 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 0.4 2.7 0.4 2.5

Note 4 - Shareholders' Equity

Note 4 - Shareholders' Equity	9 Months Ended
	Jun. 30, 2024
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. In the second 2024, which must be settled on or before September 27, 2024. third 2024, which must be settled on or before March 10, 2025. June 30, 2024, $32.6. As of June 30, 2024 under the ATM Program, Spire may Equity Units In February 2021, February 9, 2021, 1.1 8 February 16, 2021). March 1, 2024, 1/20th, one thousand 2021 2026 Note 6 March 1, 2024, March 5, 2024.

Note 5 - Regulatory Matters

Note 5 - Regulatory Matters	9 Months Ended
	Jun. 30, 2024
Notes to Financial Statements
Public Utilities Disclosure [Text Block]	5. As explained in Note 1 980, Regulated Operations June 30, 2024 September 30, 2023 June 30, 2023 June 30, September 30, June 30, Spire 2024 2023 2023 Regulatory Assets: Current: Unamortized purchased gas adjustments $ 58.0 $ 293.2 $ 66.2 Other 31.8 55.1 27.1 Total Current Regulatory Assets 89.8 348.3 93.3 Noncurrent: Pension and postretirement benefit costs 243.2 261.0 268.8 Cost of removal 658.0 633.2 597.9 Future income taxes due from customers 149.0 144.5 140.1 Energy efficiency 59.1 56.3 55.8 Unamortized purchased gas adjustments — 23.0 206.3 Other 173.5 131.2 152.3 Total Noncurrent Regulatory Assets 1,282.8 1,249.2 1,421.2 Total Regulatory Assets $ 1,372.6 $ 1,597.5 $ 1,514.5 Regulatory Liabilities: Current: Unamortized purchased gas adjustments $ 33.3 $ — $ — Other 4.6 7.3 5.5 Total Current Regulatory Liabilities 37.9 7.3 5.5 Noncurrent: Deferred taxes due to customers 117.5 128.0 131.8 Pension and postretirement benefit costs 192.3 185.2 165.3 Accrued cost of removal 135.4 126.6 107.7 Unamortized purchased gas adjustments 83.6 11.2 — Other 18.7 21.4 23.3 Total Noncurrent Regulatory Liabilities 547.5 472.4 428.1 Total Regulatory Liabilities $ 585.4 $ 479.7 $ 433.6 June 30, September 30, June 30, Spire Missouri 2024 2023 2023 Regulatory Assets: Current: Unamortized purchased gas adjustments $ 57.6 $ 269.4 $ 32.9 Other 5.4 23.7 2.1 Total Current Regulatory Assets 63.0 293.1 35.0 Noncurrent: Future income taxes due from customers 140.8 136.2 131.8 Pension and postretirement benefit costs 177.5 189.1 193.4 Energy efficiency 59.1 56.3 55.8 Unamortized purchased gas adjustments — 23.0 206.3 Cost of removal 97.0 97.0 95.3 Other 159.7 116.0 136.5 Total Noncurrent Regulatory Assets 634.1 617.6 819.1 Total Regulatory Assets $ 697.1 $ 910.7 $ 854.1 Regulatory Liabilities: Noncurrent: Deferred taxes due to customers $ 105.1 $ 114.8 $ 118.1 Pension and postretirement benefit costs 165.7 156.5 137.9 Accrued cost of removal 97.1 90.4 72.3 Unamortized purchased gas adjustments 83.6 11.2 — Other 14.2 16.5 17.8 Total Noncurrent Regulatory Liabilities 465.7 389.4 346.1 Total Regulatory Liabilities $ 465.7 $ 389.4 $ 346.1 June 30, September 30, June 30, Spire Alabama 2024 2023 2023 Regulatory Assets: Current: Unamortized purchased gas adjustments $ — $ 21.7 $ 30.9 Other 14.7 19.9 13.0 Total Current Regulatory Assets 14.7 41.6 43.9 Noncurrent: Future income taxes due from customers 1.8 2.0 2.0 Pension and postretirement benefit costs 62.3 67.8 71.1 Cost of removal 561.0 536.2 502.6 Other 0.9 0.9 1.0 Total Noncurrent Regulatory Assets 626.0 606.9 576.7 Total Regulatory Assets $ 640.7 $ 648.5 $ 620.6 Regulatory Liabilities: Current: Unamortized purchased gas adjustments $ 32.2 $ — $ — Total Current Regulatory Liabilities 32.2 — — Noncurrent: Pension and postretirement benefit costs 16.4 17.9 17.3 Other 3.2 3.3 3.5 Total Noncurrent Regulatory Liabilities 19.6 21.2 20.8 Total Regulatory Liabilities $ 51.8 $ 21.2 $ 20.8 A portion of the Company’s and Spire Missouri’s regulatory assets are not June 30, September 30, June 30, 2024 2023 2023 Spire Pension and postretirement benefit costs $ 135.9 $ 133.4 $ 127.5 Future income taxes due from customers 147.1 142.5 138.0 Unamortized purchased gas adjustments 57.6 292.4 239.2 Other 132.3 104.2 102.2 Total Regulatory Assets Not Earning a Return $ 472.9 $ 672.5 $ 606.9 Spire Missouri Pension and postretirement benefit costs $ 135.9 $ 133.4 $ 127.5 Future income taxes due from customers 140.8 136.2 131.8 Unamortized purchased gas adjustments 57.6 292.4 239.2 Other 132.3 104.2 102.2 Total Regulatory Assets Not Earning a Return $ 466.6 $ 666.2 $ 600.7 Like all the Company’s regulatory assets, these regulatory assets as of June 30, 2024 two not not 35 not not Spire Missouri In 2022, 2022 0135 2022 0136 2020 2021 February 2021 ( December 2022, 2024, no 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 2023, May 6, 2023, October 2022 February 2023. October 2023, October 23, 2023, March 2023 August 2023. January 17, 2024, September 2023 February 2024. March 2024, April 2024, May 2024. July 19, 2024, March 2024 August 2024 ( July August). In fiscal 2023, November 2022 January 2023. 2024, November 2023 June 2024 no June 30, 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, April 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	9 Months Ended
	Jun. 30, 2024
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 June 30, 2024 June 30, 2024 Spire has a commercial paper program (“CP Program”) pursuant to which it may may not may 365 On January 3, 2024, one April 5, 2024 May 6, 2024. Information about short-term borrowings, including Spire Missouri’s and Spire Alabama’s borrowings from Spire, is presented in the following table. As of June 30, 2024 Spire (Parent Only) Spire Missouri Spire Alabama Spire CP Term Spire Spire Consol- Program Loan Note Note idated Nine Months Ended June 30, 2024 Highest borrowings outstanding $ 1,135.0 $ 200.0 $ 643.6 $ 132.5 $ 1,275.0 Lowest borrowings outstanding 554.6 — 228.5 5.5 741.0 Weighted average borrowings 860.0 84.9 431.9 68.8 944.9 Weighted average interest rate 5.7 % 6.4 % 5.6 % 5.7 % 5.7 % As of June 30, 2024 Borrowings outstanding $ 771.0 $ — $ 418.3 $ 23.0 $ 771.0 Weighted average interest rate 5.6 % 0.0 % 5.6 % 5.6 % 5.6 % As of September 30, 2023 Borrowings outstanding $ 955.5 $ — $ 540.6 $ 124.1 $ 955.5 Weighted average interest rate 5.6 % 0.0 % 5.6 % 5.6 % 5.6 % As of June 30, 2023 Borrowings outstanding $ 557.6 $ — $ 228.1 $ 108.1 $ 557.6 Weighted average interest rate 5.5 % 0.0 % 5.5 % 5.5 % 5.5 % Long-term In February 2024, 2021 2026, February 2021 Note 4 February 2024, March 1, 2026, The long-term debt agreements of Spire, Spire Missouri and Spire Alabama contain customary financial covenants and default provisions. As of June 30, 2024 no On July 12, 2024, December 2, 2024 ( August 14, 2024. Interest expense shown on the statements of income is net of the capitalized interest amounts shown in the following table. Three Months Ended June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Spire $ 4.3 $ 2.3 $ 12.1 $ 5.8 Spire Missouri 1.2 1.0 3.5 2.1 Spire Alabama 0.3 0.5 1.1 1.8

Note 7 - Fair Value of Financia

Note 7 - Fair Value of Financial Instruments	9 Months Ended
	Jun. 30, 2024
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 June 30, 2024 September 30, 2023 June 30, 2023 Classification of Estimated Fair Value Carrying Amount Fair Value Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Spire As of June 30, 2024 Cash and cash equivalents $ 7.4 $ 7.4 $ 7.4 $ — Notes payable 771.0 771.0 — 771.0 Long-term debt, including current portion 3,729.3 3,407.1 — 3,407.1 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 June 30, 2023 Cash and cash equivalents $ 5.3 $ 5.3 $ 5.3 $ — Notes payable 557.6 557.6 — 557.6 Long-term debt, including current portion 3,959.9 3,650.7 — 3,650.7 Spire Missouri As of June 30, 2024 Cash and cash equivalents $ 1.3 $ 1.3 $ 1.3 $ — Notes payable – associated companies 418.3 418.3 — 418.3 Long-term debt, including current portion 1,786.6 1,626.3 — 1,626.3 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 June 30, 2023 Notes payable – associated companies $ 228.1 $ 228.1 $ — $ 228.1 Long-term debt, including current portion 2,035.1 1,890.2 — 1,890.2 Spire Alabama As of June 30, 2024 Cash and cash equivalents $ 2.3 $ 2.3 $ 2.3 $ — Notes payable – associated companies 23.0 23.0 — 23.0 Long-term debt 746.2 674.4 — 674.4 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 June 30, 2023 Cash and cash equivalents $ 0.5 $ 0.5 $ 0.5 $ — Notes payable – associated companies 108.1 108.1 — 108.1 Long-term debt 745.8 681.5 — 681.5

Note 8 - Fair Value Measurement

Note 8 - Fair Value Measurements	9 Months Ended
	Jun. 30, 2024
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 and bonds included in Level 1 Derivative instruments included in Level 1 2 2 3 no 3 June 30, 2024 September 30, 2023 June 30, 2023 The mutual funds and bonds are included in “Other Investments” on the Company’s balance sheets. The mutual funds are included 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. Derivative instruments are included in the balance sheets in “Other” current or noncurrent assets or liabilities as applicable. Spire Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Effects of Netting and Cash Margin Receivables /Payables Total As of June 30, 2024 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 24.5 $ — $ — $ 24.5 NYMEX/ICE natural gas contracts 4.8 — (4.8 ) — Gas Marketing: NYMEX/ICE natural gas contracts 6.1 — (6.1 ) — Natural gas commodity contracts — 53.9 (2.8 ) 51.1 Other: U.S. stock/bond mutual funds 30.7 — — 30.7 U.S. bonds 14.4 — — 14.4 Global bonds 1.4 — — 1.4 Interest rate swaps — 32.2 — 32.2 Total $ 81.9 $ 86.1 $ (13.7 ) $ 154.3 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 21.0 $ — $ (21.0 ) $ — Gas Marketing: NYMEX/ICE natural gas contracts 22.6 — (22.6 ) — Natural gas commodity contracts — 29.8 (2.8 ) 27.0 Total $ 43.6 $ 29.8 $ (46.4 ) $ 27.0 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 June 30, 2023 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 21.4 $ — $ — $ 21.4 Gas Marketing: NYMEX/ICE natural gas contracts 10.5 — (10.5 ) — Natural gas commodity contracts * — 35.8 (1.0 ) 34.8 Other: U.S. stock/bond mutual funds 31.4 — — 31.4 Interest rate swaps * — 22.8 — 22.8 Total $ 63.3 $ 58.6 $ (11.5 ) $ 110.4 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 44.8 $ — $ (44.8 ) $ — Gasoline and heating oil contracts 0.7 — (0.7 ) — Gas Marketing: NYMEX/ICE natural gas contracts 24.3 — (24.3 ) — Natural gas commodity contracts * — 34.9 (1.0 ) 33.9 Other: Interest rate swaps * — 0.8 — 0.8 Total $ 69.8 $ 35.7 $ (70.8 ) $ 34.7 * Subsequent to the issuance of its consolidated financial statements for the quarter ended June 30, 2023, fourth 2023, 2 1 June 30, 2023. 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 June 30, 2024 ASSETS U.S. stock/bond mutual funds $ 24.5 $ — $ — $ 24.5 NYMEX/ICE natural gas contracts 4.8 — (4.8 ) — Total $ 29.3 $ — $ (4.8 ) $ 24.5 LIABILITIES NYMEX/ICE natural gas contracts $ 21.0 $ — $ (21.0 ) $ — 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 June 30, 2023 ASSETS U.S. stock/bond mutual funds $ 21.4 $ — $ — $ 21.4 LIABILITIES NYMEX/ICE natural gas contracts $ 44.8 $ — $ (44.8 ) $ — Gasoline and heating oil contracts 0.7 — (0.7 ) — Total $ 45.5 $ — $ (45.5 ) $ —

Note 9 - Pension Plans and Othe

Note 9 - Pension Plans and Other Postretirement Benefits	9 Months Ended
	Jun. 30, 2024
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 June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Spire Service cost – benefits earned during the period $ 3.9 $ 4.2 $ 11.8 $ 12.2 Interest cost on projected benefit obligation 6.6 6.6 20.0 18.9 Expected return on plan assets (6.3 ) (6.4 ) (18.7 ) (18.5 ) Amortization of prior service credit (1.1 ) (1.1 ) (3.4 ) (3.4 ) Amortization of actuarial loss 1.6 1.5 4.8 4.7 Loss on lump-sum settlements 1.0 — 1.0 8.6 Subtotal 5.7 4.8 15.5 22.5 Regulatory adjustment 8.8 6.1 26.3 18.3 Net pension cost $ 14.5 $ 10.9 $ 41.8 $ 40.8 Spire Missouri Service cost – benefits earned during the period $ 2.6 $ 2.8 $ 7.8 $ 8.5 Interest cost on projected benefit obligation 4.7 4.5 14.2 13.4 Expected return on plan assets (4.3 ) (4.5 ) (12.8 ) (13.5 ) Amortization of prior service credit (0.5 ) (0.5 ) (1.5 ) (1.5 ) Amortization of actuarial loss 1.5 1.5 4.4 4.6 Loss on lump-sum settlements 1.0 — 1.0 — Subtotal 5.0 3.8 13.1 11.5 Regulatory adjustment 6.2 3.4 18.8 19.6 Net pension cost $ 11.2 $ 7.2 $ 31.9 $ 31.1 Spire Alabama Service cost – benefits earned during the period $ 1.2 $ 1.3 $ 3.5 $ 3.2 Interest cost on projected benefit obligation 1.3 1.5 3.8 3.6 Expected return on plan assets (1.2 ) (1.1 ) (3.6 ) (2.7 ) Amortization of prior service credit (0.6 ) (0.6 ) (1.8 ) (1.8 ) Amortization of actuarial loss 0.2 0.1 0.7 0.4 Subtotal 0.9 1.2 2.6 11.3 Regulatory adjustment 2.3 2.4 6.8 (2.0 ) Net pension cost $ 3.2 $ 3.6 $ 9.4 $ 9.3 Pursuant to the provisions of Spire Missouri’s and Spire Alabama’s pension plans, pension obligations may . For the three nine June 30, 2024 , one September 30, 2023. For the three nine June 30, 2023, two one September 30, 2022. one three nine June 30, 2023. 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 June 30, 2024 $10.0 none 2024 June 30, 2024 $8.0 . C 2024. C 2024 $8.4 . 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 June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Spire Service cost – benefits earned during the period $ 1.2 $ 1.2 $ 3.3 $ 3.6 Interest cost on accumulated postretirement benefit obligation 2.1 2.0 6.6 6.3 Expected return on plan assets (3.7 ) (4.0 ) (11.9 ) (11.8 ) Amortization of prior service cost — 0.1 0.2 0.2 Amortization of actuarial gain (1.2 ) (0.9 ) (3.3 ) (3.0 ) Subtotal (1.6 ) (1.6 ) (5.1 ) (4.7 ) Regulatory adjustment 0.1 (0.5 ) 0.6 (0.2 ) Net postretirement benefit income $ (1.5 ) $ (2.1 ) $ (4.5 ) $ (4.9 ) Spire Missouri Service cost – benefits earned during the period $ 0.9 $ 1.0 $ 2.7 $ 3.0 Interest cost on accumulated postretirement benefit obligation 1.6 1.6 4.9 4.9 Expected return on plan assets (2.5 ) (2.6 ) (7.9 ) (7.9 ) Amortization of prior service cost 0.1 0.1 0.4 0.4 Amortization of actuarial gain (1.0 ) (0.8 ) (2.8 ) (2.4 ) Subtotal (0.9 ) (0.7 ) (2.7 ) (2.0 ) Regulatory adjustment 0.6 (0.2 ) 1.9 1.1 Net postretirement benefit income $ (0.3 ) $ (0.9 ) $ (0.8 ) $ (0.9 ) Spire Alabama Service cost – benefits earned during the period $ 0.2 $ 0.2 $ 0.5 $ 0.5 Interest cost on accumulated postretirement benefit obligation 0.5 0.4 1.6 1.3 Expected return on plan assets (1.2 ) (1.3 ) (3.8 ) (3.8 ) Amortization of prior service credit (0.1 ) — (0.2 ) (0.2 ) Amortization of actuarial gain — (0.1 ) (0.1 ) (0.4 ) Subtotal (0.6 ) (0.8 ) (2.0 ) (2.6 ) Regulatory adjustment (0.5 ) (0.5 ) (1.4 ) (1.4 ) Net postretirement benefit income $ (1.1 ) $ (1.3 ) $ (3.4 ) $ (4.0 ) 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 June 30, 2024

Note 10 - Information by Operat

Note 10 - Information by Operating Segment	9 Months Ended
	Jun. 30, 2024
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 June 30, 2024 Revenues from external customers $ 371.3 $ 21.2 $ 21.3 $ 0.3 $ — $ 414.1 Intersegment revenues 1.4 — 11.2 4.5 (17.1 ) — Total Operating Revenues 372.7 21.2 32.5 4.8 (17.1 ) 414.1 Depreciation and amortization expense 66.7 0.3 4.2 0.2 — 71.4 Interest expense 34.9 — 1.7 22.3 (10.1 ) 48.8 Income tax (benefit) expense (0.9 ) (1.1 ) 3.6 (4.7 ) — (3.1 ) Net economic (loss) earnings (11.0 ) 1.0 13.9 (8.2 ) — (4.3 ) Capital expenditures 189.2 — 33.1 — (0.1 ) 222.2 Gas Utility Gas Marketing Midstream Other Eliminations Consolidated Three Months Ended June 30, 2023 Revenues from external customers $ 387.5 $ 23.1 $ 7.7 $ 0.2 $ — $ 418.5 Intersegment revenues 0.3 — 9.7 4.1 (14.1 ) — Total Operating Revenues 387.8 23.1 17.4 4.3 (14.1 ) 418.5 Depreciation and amortization expense 61.7 0.3 2.1 0.2 — 64.3 Interest expense 35.6 — 2.3 15.7 (6.9 ) 46.7 Income tax (benefit) expense (3.6 ) (1.7 ) 1.2 (2.7 ) — (6.8 ) Net economic (loss) earnings (12.3 ) (2.5 ) 3.6 (7.4 ) — (18.6 ) Capital expenditures 149.1 — 26.6 (0.2 ) — 175.5 Gas Utility Gas Marketing Midstream Other Eliminations Consolidated Nine Months Ended June 30, 2024 Revenues from external customers $ 2,158.9 $ 103.5 $ 36.3 $ 0.5 $ — $ 2,299.2 Intersegment revenues 1.7 — 32.6 12.5 (46.8 ) — Total Operating Revenues 2,160.6 103.5 68.9 13.0 (46.8 ) 2,299.2 Depreciation and amortization expense 196.3 1.1 9.5 0.4 — 207.3 Interest expense 112.2 — 5.5 68.6 (34.7 ) 151.6 Income tax expense (benefit) 56.5 10.3 5.7 (5.2 ) — 67.3 Net economic earnings (loss) 252.8 23.7 20.1 (21.6 ) — 275.0 Capital expenditures 501.4 — 131.1 — (1.0 ) 631.5 Gas Utility Gas Marketing Midstream Other Eliminations Consolidated Nine Months Ended June 30, 2023 Revenues from external customers $ 2,174.9 $ 157.8 $ 22.7 $ 0.5 $ — $ 2,355.9 Intersegment revenues 0.4 — 26.4 11.9 (38.7 ) — Total Operating Revenues 2,175.3 157.8 49.1 12.4 (38.7 ) 2,355.9 Depreciation and amortization expense 181.6 1.0 6.0 0.4 - 189.0 Interest expense 103.2 — 6.1 52.2 (24.0 ) 137.5 Income tax expense (benefit) 47.7 9.6 4.1 (5.7 ) — 55.7 Net economic earnings (loss) 234.5 45.0 11.6 (25.4 ) — 265.7 Capital expenditures 439.1 0.2 43.6 0.4 — 483.3 The following table reconciles the Company’s net economic earnings (loss) to net income (loss). Three Months Ended June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Net (Loss) Income $ (12.6 ) $ (21.6 ) $ 276.8 $ 248.6 Adjustments, pre-tax: Fair value and timing adjustments 6.2 3.4 (9.2 ) 22.2 Acquisition and restructuring activities 4.8 0.5 6.7 0.5 Income tax adjustments (2.7 ) (0.9 ) 0.7 (5.6 ) Net Economic (Loss) Earnings $ (4.3 ) $ (18.6 ) $ 275.0 $ 265.7 The Company’s total assets by segment were as follows: June 30, September 30, June 30, 2024 2023 2023 Total Assets: Gas Utility $ 8,601.9 $ 8,486.7 $ 8,283.2 Gas Marketing 212.3 332.0 316.6 Midstream 871.9 574.3 533.3 Other 2,627.4 2,533.3 2,134.1 Eliminations (1,602.6 ) (1,612.7 ) (1,229.7 ) Total Assets $ 10,710.9 $ 10,313.6 $ 10,037.5

Note 11 - Commitments and Conti

Note 11 - Commitments and Contingencies	9 Months Ended
	Jun. 30, 2024
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, June 30, 2024 November April. Spire is a limited partner in several unconsolidated partnerships, predominantly focusing on sustainability and development initiatives tied to the natural gas utility sector. Spire committed to contribute a total of $25.3 of capital to the partnerships as and when requested by the respective general partners. As of June 30, 2024, 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 May 2023, 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	6 Months Ended	9 Months Ended
	Jun. 30, 2024	Jun. 30, 2024
Insider Trading Arr Line Items
Material Terms of Trading Arrangement [Text Block]		5. During the quarterly period ended June 30, 2024 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)	9 Months Ended
	Jun. 30, 2024
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 June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Spire Missouri Purchases of natural gas from Spire Marketing $ — $ 6.5 $ 10.6 $ 48.8 Transportation services received from Spire STL Pipeline 7.9 8.0 24.4 23.9 Transportation services received from Spire MoGas Pipeline 1.7 — 3.1 — Sales of natural gas to Spire Marketing 1.4 0.3 1.7 0.4 Natural gas storage services from Spire Storage Salt Plains LLC — — 0.7 — Spire Alabama Purchases of natural gas from Spire Marketing $ — $ 1.7 $ 3.4 $ 2.8
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]	RESTRICTED CASH AND OTHER INVESTMENTS June 30, 2024 June 30, 2024 September 30, 2023 June 30, 2023
Business Combinations Policy [Policy Text Block]	BUSINESS COMBINATIONS January 19, 2024, 75 805, Business Combinations not three nine June 30, 2024.
Accrued Capital Expenditures [Policy Text Block]	ACCRUED CAPITAL EXPENDITURES June 30, September 30, June 30, 2024 2023 2023 Spire $ 81.6 $ 104.3 $ 62.2 Spire Missouri 43.5 56.5 33.4 Spire Alabama 5.5 4.6 4.5
Receivable [Policy Text Block]	ACCOUNTS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES not Spire Spire Missouri Spire Alabama Three Months Ended June 30, 2024 2023 2024 2023 2024 2023 Allowance at beginning of period $ 39.1 $ 40.6 $ 32.0 $ 34.5 $ 6.2 $ 5.3 Provision for expected credit losses 5.6 1.2 4.7 0.3 0.7 0.8 Write-offs, net of recoveries (11.5 ) (7.1 ) (10.1 ) (6.1 ) (1.2 ) (0.8 ) Allowance at end of period $ 33.2 $ 34.7 $ 26.6 $ 28.7 $ 5.7 $ 5.3 Nine Months Ended June 30, 2024 2023 2024 2023 2024 2023 Allowance at beginning of period $ 32.5 $ 31.9 $ 26.2 $ 24.9 $ 5.7 $ 6.3 Provision for expected credit losses 17.6 13.5 14.5 11.4 2.4 1.5 Write-offs, net of recoveries (16.9 ) (10.7 ) (14.1 ) (7.6 ) (2.4 ) (2.5 ) Allowance at end of period $ 33.2 $ 34.7 $ 26.6 $ 28.7 $ 5.7 $ 5.3

Note 1 - Summary of Significa_2

Note 1 - Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Jun. 30, 2024
Notes Tables
Schedule of Related Party Transactions [Table Text Block]	Three Months Ended June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Spire Missouri Purchases of natural gas from Spire Marketing $ — $ 6.5 $ 10.6 $ 48.8 Transportation services received from Spire STL Pipeline 7.9 8.0 24.4 23.9 Transportation services received from Spire MoGas Pipeline 1.7 — 3.1 — Sales of natural gas to Spire Marketing 1.4 0.3 1.7 0.4 Natural gas storage services from Spire Storage Salt Plains LLC — — 0.7 — Spire Alabama Purchases of natural gas from Spire Marketing $ — $ 1.7 $ 3.4 $ 2.8
Schedule Of Capital Expenditure Excluded From Statement Of Cash Flow [Table Text Block]	June 30, September 30, June 30, 2024 2023 2023 Spire $ 81.6 $ 104.3 $ 62.2 Spire Missouri 43.5 56.5 33.4 Spire Alabama 5.5 4.6 4.5
Accounts Receivable, Allowance for Credit Loss [Table Text Block]	Spire Spire Missouri Spire Alabama Three Months Ended June 30, 2024 2023 2024 2023 2024 2023 Allowance at beginning of period $ 39.1 $ 40.6 $ 32.0 $ 34.5 $ 6.2 $ 5.3 Provision for expected credit losses 5.6 1.2 4.7 0.3 0.7 0.8 Write-offs, net of recoveries (11.5 ) (7.1 ) (10.1 ) (6.1 ) (1.2 ) (0.8 ) Allowance at end of period $ 33.2 $ 34.7 $ 26.6 $ 28.7 $ 5.7 $ 5.3 Nine Months Ended June 30, 2024 2023 2024 2023 2024 2023 Allowance at beginning of period $ 32.5 $ 31.9 $ 26.2 $ 24.9 $ 5.7 $ 6.3 Provision for expected credit losses 17.6 13.5 14.5 11.4 2.4 1.5 Write-offs, net of recoveries (16.9 ) (10.7 ) (14.1 ) (7.6 ) (2.4 ) (2.5 ) Allowance at end of period $ 33.2 $ 34.7 $ 26.6 $ 28.7 $ 5.7 $ 5.3

Note 2 - Revenue (Tables)

Note 2 - Revenue (Tables)	9 Months Ended
	Jun. 30, 2024
Notes Tables
Disaggregation of Revenue [Table Text Block]	Three Months Ended June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Spire Gas Utility: Residential $ 232.2 $ 238.1 $ 1,454.5 $ 1,486.3 Commercial and industrial 87.3 102.2 513.1 533.1 Transportation 30.3 29.0 99.7 93.2 Off-system and other incentive 9.6 8.2 29.0 21.9 Other customer revenue 6.5 5.1 20.2 13.8 Total revenue from contracts with customers 365.9 382.6 2,116.5 2,148.3 Changes in accrued revenue under alternative revenue programs 6.8 5.2 44.1 27.0 Total Gas Utility operating revenues 372.7 387.8 2,160.6 2,175.3 Gas Marketing 21.2 23.1 103.5 157.8 Midstream 32.5 17.4 68.9 49.1 Other 4.8 4.3 13.0 12.4 Total before eliminations 431.2 432.6 2,346.0 2,394.6 Intersegment eliminations (see Note 10, Information by Operating Segment) (17.1 ) (14.1 ) (46.8 ) (38.7 ) Total Operating Revenues $ 414.1 $ 418.5 $ 2,299.2 $ 2,355.9 Spire Missouri Residential $ 169.5 $ 171.7 $ 1,091.2 $ 1,142.3 Commercial and industrial 52.6 61.1 348.5 369.2 Transportation 7.5 7.1 26.6 26.1 Off-system and other incentive 7.0 6.0 23.4 15.6 Other customer revenue 4.2 3.8 11.7 10.1 Total revenue from contracts with customers 240.8 249.7 1,501.4 1,563.3 Changes in accrued revenue under alternative revenue programs 8.0 4.1 49.3 22.7 Total Operating Revenues $ 248.8 $ 253.8 $ 1,550.7 $ 1,586.0 Spire Alabama Residential $ 53.0 $ 56.7 $ 306.7 $ 288.1 Commercial and industrial 26.9 32.7 130.4 127.8 Transportation 20.3 18.9 65.1 59.0 Off-system and other incentive 2.6 2.2 5.6 6.3 Other customer revenue 0.9 0.8 2.5 2.7 Total revenue from contracts with customers 103.7 111.3 510.3 483.9 Changes in accrued revenue under alternative revenue programs (0.2 ) 1.8 (5.2 ) (0.1 ) Total Operating Revenues $ 103.5 $ 113.1 $ 505.1 $ 483.8
Schedule Of Taxes On Revenues [Table Text Block]	Three Months Ended June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Spire $ 22.4 $ 26.0 $ 113.5 $ 116.6 Spire Missouri 16.3 18.9 82.8 86.6 Spire Alabama 5.3 6.1 26.3 25.5

Note 3 - Earnings Per Common _2

Note 3 - Earnings Per Common Share (Tables)	9 Months Ended
	Jun. 30, 2024
Notes Tables
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Three Months Ended June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Basic Earnings Per Common Share: Net (Loss) Income $ (12.6 ) $ (21.6 ) $ 276.8 $ 248.6 Less: Provision for preferred dividends 3.7 3.7 11.1 11.1 (Loss) Income allocated to participating securities — (0.1 ) 0.4 0.4 (Loss) Income Available to Common Shareholders $ (16.3 ) $ (25.2 ) $ 265.3 $ 237.1 Weighted Average Common Shares Outstanding (in millions) 57.7 52.5 55.6 52.5 Basic (Loss) Earnings Per Common Share $ (0.28 ) $ (0.48 ) $ 4.77 $ 4.52 Diluted Earnings Per Common Share: Net (Loss) Income $ (12.6 ) $ (21.6 ) $ 276.8 $ 248.6 Less: Provision for preferred dividends 3.7 3.7 11.1 11.1 (Loss) Income allocated to participating securities — (0.1 ) 0.4 0.4 (Loss) Income Available to Common Shareholders $ (16.3 ) $ (25.2 ) $ 265.3 $ 237.1 Weighted Average Common Shares Outstanding (in millions) 57.7 52.5 55.6 52.5 Dilutive Effect of forward sales of common stock, restricted stock and restricted stock units (in millions)* — — 0.1 0.1 Weighted Average Diluted Common Shares (in millions) 57.7 52.5 55.7 52.6 Diluted (Loss) Earnings Per Common Share $ (0.28 ) $ (0.48 ) $ 4.76 $ 4.51 * 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 0.4 2.7 0.4 2.5

Note 5 - Regulatory Matters (Ta

Note 5 - Regulatory Matters (Tables)	9 Months Ended
	Jun. 30, 2024
Notes Tables
Schedule of Regulatory Assets and Liabilities [Table Text Block]	June 30, September 30, June 30, Spire 2024 2023 2023 Regulatory Assets: Current: Unamortized purchased gas adjustments $ 58.0 $ 293.2 $ 66.2 Other 31.8 55.1 27.1 Total Current Regulatory Assets 89.8 348.3 93.3 Noncurrent: Pension and postretirement benefit costs 243.2 261.0 268.8 Cost of removal 658.0 633.2 597.9 Future income taxes due from customers 149.0 144.5 140.1 Energy efficiency 59.1 56.3 55.8 Unamortized purchased gas adjustments — 23.0 206.3 Other 173.5 131.2 152.3 Total Noncurrent Regulatory Assets 1,282.8 1,249.2 1,421.2 Total Regulatory Assets $ 1,372.6 $ 1,597.5 $ 1,514.5 Regulatory Liabilities: Current: Unamortized purchased gas adjustments $ 33.3 $ — $ — Other 4.6 7.3 5.5 Total Current Regulatory Liabilities 37.9 7.3 5.5 Noncurrent: Deferred taxes due to customers 117.5 128.0 131.8 Pension and postretirement benefit costs 192.3 185.2 165.3 Accrued cost of removal 135.4 126.6 107.7 Unamortized purchased gas adjustments 83.6 11.2 — Other 18.7 21.4 23.3 Total Noncurrent Regulatory Liabilities 547.5 472.4 428.1 Total Regulatory Liabilities $ 585.4 $ 479.7 $ 433.6 June 30, September 30, June 30, Spire Missouri 2024 2023 2023 Regulatory Assets: Current: Unamortized purchased gas adjustments $ 57.6 $ 269.4 $ 32.9 Other 5.4 23.7 2.1 Total Current Regulatory Assets 63.0 293.1 35.0 Noncurrent: Future income taxes due from customers 140.8 136.2 131.8 Pension and postretirement benefit costs 177.5 189.1 193.4 Energy efficiency 59.1 56.3 55.8 Unamortized purchased gas adjustments — 23.0 206.3 Cost of removal 97.0 97.0 95.3 Other 159.7 116.0 136.5 Total Noncurrent Regulatory Assets 634.1 617.6 819.1 Total Regulatory Assets $ 697.1 $ 910.7 $ 854.1 Regulatory Liabilities: Noncurrent: Deferred taxes due to customers $ 105.1 $ 114.8 $ 118.1 Pension and postretirement benefit costs 165.7 156.5 137.9 Accrued cost of removal 97.1 90.4 72.3 Unamortized purchased gas adjustments 83.6 11.2 — Other 14.2 16.5 17.8 Total Noncurrent Regulatory Liabilities 465.7 389.4 346.1 Total Regulatory Liabilities $ 465.7 $ 389.4 $ 346.1 June 30, September 30, June 30, Spire Alabama 2024 2023 2023 Regulatory Assets: Current: Unamortized purchased gas adjustments $ — $ 21.7 $ 30.9 Other 14.7 19.9 13.0 Total Current Regulatory Assets 14.7 41.6 43.9 Noncurrent: Future income taxes due from customers 1.8 2.0 2.0 Pension and postretirement benefit costs 62.3 67.8 71.1 Cost of removal 561.0 536.2 502.6 Other 0.9 0.9 1.0 Total Noncurrent Regulatory Assets 626.0 606.9 576.7 Total Regulatory Assets $ 640.7 $ 648.5 $ 620.6 Regulatory Liabilities: Current: Unamortized purchased gas adjustments $ 32.2 $ — $ — Total Current Regulatory Liabilities 32.2 — — Noncurrent: Pension and postretirement benefit costs 16.4 17.9 17.3 Other 3.2 3.3 3.5 Total Noncurrent Regulatory Liabilities 19.6 21.2 20.8 Total Regulatory Liabilities $ 51.8 $ 21.2 $ 20.8
Schedule of Regulatory Assets Not Earning Return [Table Text Block]	June 30, September 30, June 30, 2024 2023 2023 Spire Pension and postretirement benefit costs $ 135.9 $ 133.4 $ 127.5 Future income taxes due from customers 147.1 142.5 138.0 Unamortized purchased gas adjustments 57.6 292.4 239.2 Other 132.3 104.2 102.2 Total Regulatory Assets Not Earning a Return $ 472.9 $ 672.5 $ 606.9 Spire Missouri Pension and postretirement benefit costs $ 135.9 $ 133.4 $ 127.5 Future income taxes due from customers 140.8 136.2 131.8 Unamortized purchased gas adjustments 57.6 292.4 239.2 Other 132.3 104.2 102.2 Total Regulatory Assets Not Earning a Return $ 466.6 $ 666.2 $ 600.7

Note 6 - Financing (Tables)

Note 6 - Financing (Tables)	9 Months Ended
	Jun. 30, 2024
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 Nine Months Ended June 30, 2024 Highest borrowings outstanding $ 1,135.0 $ 200.0 $ 643.6 $ 132.5 $ 1,275.0 Lowest borrowings outstanding 554.6 — 228.5 5.5 741.0 Weighted average borrowings 860.0 84.9 431.9 68.8 944.9 Weighted average interest rate 5.7 % 6.4 % 5.6 % 5.7 % 5.7 % As of June 30, 2024 Borrowings outstanding $ 771.0 $ — $ 418.3 $ 23.0 $ 771.0 Weighted average interest rate 5.6 % 0.0 % 5.6 % 5.6 % 5.6 % As of September 30, 2023 Borrowings outstanding $ 955.5 $ — $ 540.6 $ 124.1 $ 955.5 Weighted average interest rate 5.6 % 0.0 % 5.6 % 5.6 % 5.6 % As of June 30, 2023 Borrowings outstanding $ 557.6 $ — $ 228.1 $ 108.1 $ 557.6 Weighted average interest rate 5.5 % 0.0 % 5.5 % 5.5 % 5.5 %
Summary Of Capitalized Interest [Table Text Block]	Three Months Ended June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Spire $ 4.3 $ 2.3 $ 12.1 $ 5.8 Spire Missouri 1.2 1.0 3.5 2.1 Spire Alabama 0.3 0.5 1.1 1.8

Note 7 - Fair Value of Financ_2

Note 7 - Fair Value of Financial Instruments (Tables)	9 Months Ended
	Jun. 30, 2024
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 June 30, 2024 Cash and cash equivalents $ 7.4 $ 7.4 $ 7.4 $ — Notes payable 771.0 771.0 — 771.0 Long-term debt, including current portion 3,729.3 3,407.1 — 3,407.1 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 June 30, 2023 Cash and cash equivalents $ 5.3 $ 5.3 $ 5.3 $ — Notes payable 557.6 557.6 — 557.6 Long-term debt, including current portion 3,959.9 3,650.7 — 3,650.7 Spire Missouri As of June 30, 2024 Cash and cash equivalents $ 1.3 $ 1.3 $ 1.3 $ — Notes payable – associated companies 418.3 418.3 — 418.3 Long-term debt, including current portion 1,786.6 1,626.3 — 1,626.3 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 June 30, 2023 Notes payable – associated companies $ 228.1 $ 228.1 $ — $ 228.1 Long-term debt, including current portion 2,035.1 1,890.2 — 1,890.2 Spire Alabama As of June 30, 2024 Cash and cash equivalents $ 2.3 $ 2.3 $ 2.3 $ — Notes payable – associated companies 23.0 23.0 — 23.0 Long-term debt 746.2 674.4 — 674.4 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 June 30, 2023 Cash and cash equivalents $ 0.5 $ 0.5 $ 0.5 $ — Notes payable – associated companies 108.1 108.1 — 108.1 Long-term debt 745.8 681.5 — 681.5

Note 8 - Fair Value Measureme_2

Note 8 - Fair Value Measurements (Tables)	9 Months Ended
	Jun. 30, 2024
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 June 30, 2024 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 24.5 $ — $ — $ 24.5 NYMEX/ICE natural gas contracts 4.8 — (4.8 ) — Gas Marketing: NYMEX/ICE natural gas contracts 6.1 — (6.1 ) — Natural gas commodity contracts — 53.9 (2.8 ) 51.1 Other: U.S. stock/bond mutual funds 30.7 — — 30.7 U.S. bonds 14.4 — — 14.4 Global bonds 1.4 — — 1.4 Interest rate swaps — 32.2 — 32.2 Total $ 81.9 $ 86.1 $ (13.7 ) $ 154.3 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 21.0 $ — $ (21.0 ) $ — Gas Marketing: NYMEX/ICE natural gas contracts 22.6 — (22.6 ) — Natural gas commodity contracts — 29.8 (2.8 ) 27.0 Total $ 43.6 $ 29.8 $ (46.4 ) $ 27.0 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 June 30, 2023 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 21.4 $ — $ — $ 21.4 Gas Marketing: NYMEX/ICE natural gas contracts 10.5 — (10.5 ) — Natural gas commodity contracts * — 35.8 (1.0 ) 34.8 Other: U.S. stock/bond mutual funds 31.4 — — 31.4 Interest rate swaps * — 22.8 — 22.8 Total $ 63.3 $ 58.6 $ (11.5 ) $ 110.4 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 44.8 $ — $ (44.8 ) $ — Gasoline and heating oil contracts 0.7 — (0.7 ) — Gas Marketing: NYMEX/ICE natural gas contracts 24.3 — (24.3 ) — Natural gas commodity contracts * — 34.9 (1.0 ) 33.9 Other: Interest rate swaps * — 0.8 — 0.8 Total $ 69.8 $ 35.7 $ (70.8 ) $ 34.7 Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Effects of Netting and Cash Margin Receivables /Payables Total As of June 30, 2024 ASSETS U.S. stock/bond mutual funds $ 24.5 $ — $ — $ 24.5 NYMEX/ICE natural gas contracts 4.8 — (4.8 ) — Total $ 29.3 $ — $ (4.8 ) $ 24.5 LIABILITIES NYMEX/ICE natural gas contracts $ 21.0 $ — $ (21.0 ) $ — 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 June 30, 2023 ASSETS U.S. stock/bond mutual funds $ 21.4 $ — $ — $ 21.4 LIABILITIES NYMEX/ICE natural gas contracts $ 44.8 $ — $ (44.8 ) $ — Gasoline and heating oil contracts 0.7 — (0.7 ) — Total $ 45.5 $ — $ (45.5 ) $ —

Note 9 - Pension Plans and Ot_2

Note 9 - Pension Plans and Other Postretirement Benefits (Tables)	9 Months Ended
	Jun. 30, 2024
Notes Tables
Schedule of Net Benefit Costs [Table Text Block]	Three Months Ended June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Spire Service cost – benefits earned during the period $ 3.9 $ 4.2 $ 11.8 $ 12.2 Interest cost on projected benefit obligation 6.6 6.6 20.0 18.9 Expected return on plan assets (6.3 ) (6.4 ) (18.7 ) (18.5 ) Amortization of prior service credit (1.1 ) (1.1 ) (3.4 ) (3.4 ) Amortization of actuarial loss 1.6 1.5 4.8 4.7 Loss on lump-sum settlements 1.0 — 1.0 8.6 Subtotal 5.7 4.8 15.5 22.5 Regulatory adjustment 8.8 6.1 26.3 18.3 Net pension cost $ 14.5 $ 10.9 $ 41.8 $ 40.8 Spire Missouri Service cost – benefits earned during the period $ 2.6 $ 2.8 $ 7.8 $ 8.5 Interest cost on projected benefit obligation 4.7 4.5 14.2 13.4 Expected return on plan assets (4.3 ) (4.5 ) (12.8 ) (13.5 ) Amortization of prior service credit (0.5 ) (0.5 ) (1.5 ) (1.5 ) Amortization of actuarial loss 1.5 1.5 4.4 4.6 Loss on lump-sum settlements 1.0 — 1.0 — Subtotal 5.0 3.8 13.1 11.5 Regulatory adjustment 6.2 3.4 18.8 19.6 Net pension cost $ 11.2 $ 7.2 $ 31.9 $ 31.1 Spire Alabama Service cost – benefits earned during the period $ 1.2 $ 1.3 $ 3.5 $ 3.2 Interest cost on projected benefit obligation 1.3 1.5 3.8 3.6 Expected return on plan assets (1.2 ) (1.1 ) (3.6 ) (2.7 ) Amortization of prior service credit (0.6 ) (0.6 ) (1.8 ) (1.8 ) Amortization of actuarial loss 0.2 0.1 0.7 0.4 Subtotal 0.9 1.2 2.6 11.3 Regulatory adjustment 2.3 2.4 6.8 (2.0 ) Net pension cost $ 3.2 $ 3.6 $ 9.4 $ 9.3 Three Months Ended June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Spire Service cost – benefits earned during the period $ 1.2 $ 1.2 $ 3.3 $ 3.6 Interest cost on accumulated postretirement benefit obligation 2.1 2.0 6.6 6.3 Expected return on plan assets (3.7 ) (4.0 ) (11.9 ) (11.8 ) Amortization of prior service cost — 0.1 0.2 0.2 Amortization of actuarial gain (1.2 ) (0.9 ) (3.3 ) (3.0 ) Subtotal (1.6 ) (1.6 ) (5.1 ) (4.7 ) Regulatory adjustment 0.1 (0.5 ) 0.6 (0.2 ) Net postretirement benefit income $ (1.5 ) $ (2.1 ) $ (4.5 ) $ (4.9 ) Spire Missouri Service cost – benefits earned during the period $ 0.9 $ 1.0 $ 2.7 $ 3.0 Interest cost on accumulated postretirement benefit obligation 1.6 1.6 4.9 4.9 Expected return on plan assets (2.5 ) (2.6 ) (7.9 ) (7.9 ) Amortization of prior service cost 0.1 0.1 0.4 0.4 Amortization of actuarial gain (1.0 ) (0.8 ) (2.8 ) (2.4 ) Subtotal (0.9 ) (0.7 ) (2.7 ) (2.0 ) Regulatory adjustment 0.6 (0.2 ) 1.9 1.1 Net postretirement benefit income $ (0.3 ) $ (0.9 ) $ (0.8 ) $ (0.9 ) Spire Alabama Service cost – benefits earned during the period $ 0.2 $ 0.2 $ 0.5 $ 0.5 Interest cost on accumulated postretirement benefit obligation 0.5 0.4 1.6 1.3 Expected return on plan assets (1.2 ) (1.3 ) (3.8 ) (3.8 ) Amortization of prior service credit (0.1 ) — (0.2 ) (0.2 ) Amortization of actuarial gain — (0.1 ) (0.1 ) (0.4 ) Subtotal (0.6 ) (0.8 ) (2.0 ) (2.6 ) Regulatory adjustment (0.5 ) (0.5 ) (1.4 ) (1.4 ) Net postretirement benefit income $ (1.1 ) $ (1.3 ) $ (3.4 ) $ (4.0 )

Note 10 - Information by Oper_2

Note 10 - Information by Operating Segment (Tables)	9 Months Ended
	Jun. 30, 2024
Notes Tables
Schedule of Segment Reporting Information, by Segment [Table Text Block]	Gas Utility Gas Marketing Midstream Other Eliminations Consolidated Three Months Ended June 30, 2024 Revenues from external customers $ 371.3 $ 21.2 $ 21.3 $ 0.3 $ — $ 414.1 Intersegment revenues 1.4 — 11.2 4.5 (17.1 ) — Total Operating Revenues 372.7 21.2 32.5 4.8 (17.1 ) 414.1 Depreciation and amortization expense 66.7 0.3 4.2 0.2 — 71.4 Interest expense 34.9 — 1.7 22.3 (10.1 ) 48.8 Income tax (benefit) expense (0.9 ) (1.1 ) 3.6 (4.7 ) — (3.1 ) Net economic (loss) earnings (11.0 ) 1.0 13.9 (8.2 ) — (4.3 ) Capital expenditures 189.2 — 33.1 — (0.1 ) 222.2 Gas Utility Gas Marketing Midstream Other Eliminations Consolidated Three Months Ended June 30, 2023 Revenues from external customers $ 387.5 $ 23.1 $ 7.7 $ 0.2 $ — $ 418.5 Intersegment revenues 0.3 — 9.7 4.1 (14.1 ) — Total Operating Revenues 387.8 23.1 17.4 4.3 (14.1 ) 418.5 Depreciation and amortization expense 61.7 0.3 2.1 0.2 — 64.3 Interest expense 35.6 — 2.3 15.7 (6.9 ) 46.7 Income tax (benefit) expense (3.6 ) (1.7 ) 1.2 (2.7 ) — (6.8 ) Net economic (loss) earnings (12.3 ) (2.5 ) 3.6 (7.4 ) — (18.6 ) Capital expenditures 149.1 — 26.6 (0.2 ) — 175.5 Gas Utility Gas Marketing Midstream Other Eliminations Consolidated Nine Months Ended June 30, 2024 Revenues from external customers $ 2,158.9 $ 103.5 $ 36.3 $ 0.5 $ — $ 2,299.2 Intersegment revenues 1.7 — 32.6 12.5 (46.8 ) — Total Operating Revenues 2,160.6 103.5 68.9 13.0 (46.8 ) 2,299.2 Depreciation and amortization expense 196.3 1.1 9.5 0.4 — 207.3 Interest expense 112.2 — 5.5 68.6 (34.7 ) 151.6 Income tax expense (benefit) 56.5 10.3 5.7 (5.2 ) — 67.3 Net economic earnings (loss) 252.8 23.7 20.1 (21.6 ) — 275.0 Capital expenditures 501.4 — 131.1 — (1.0 ) 631.5 Gas Utility Gas Marketing Midstream Other Eliminations Consolidated Nine Months Ended June 30, 2023 Revenues from external customers $ 2,174.9 $ 157.8 $ 22.7 $ 0.5 $ — $ 2,355.9 Intersegment revenues 0.4 — 26.4 11.9 (38.7 ) — Total Operating Revenues 2,175.3 157.8 49.1 12.4 (38.7 ) 2,355.9 Depreciation and amortization expense 181.6 1.0 6.0 0.4 - 189.0 Interest expense 103.2 — 6.1 52.2 (24.0 ) 137.5 Income tax expense (benefit) 47.7 9.6 4.1 (5.7 ) — 55.7 Net economic earnings (loss) 234.5 45.0 11.6 (25.4 ) — 265.7 Capital expenditures 439.1 0.2 43.6 0.4 — 483.3
Reconciliation Of Consolidated Net Economic Earnings To Consolidated Net Income [Table Text Block]	Three Months Ended June 30, Nine Months Ended June 30, 2024 2023 2024 2023 Net (Loss) Income $ (12.6 ) $ (21.6 ) $ 276.8 $ 248.6 Adjustments, pre-tax: Fair value and timing adjustments 6.2 3.4 (9.2 ) 22.2 Acquisition and restructuring activities 4.8 0.5 6.7 0.5 Income tax adjustments (2.7 ) (0.9 ) 0.7 (5.6 ) Net Economic (Loss) Earnings $ (4.3 ) $ (18.6 ) $ 275.0 $ 265.7
Reconciliation of Assets from Segment to Consolidated [Table Text Block]	June 30, September 30, June 30, 2024 2023 2023 Total Assets: Gas Utility $ 8,601.9 $ 8,486.7 $ 8,283.2 Gas Marketing 212.3 332.0 316.6 Midstream 871.9 574.3 533.3 Other 2,627.4 2,533.3 2,134.1 Eliminations (1,602.6 ) (1,612.7 ) (1,229.7 ) Total Assets $ 10,710.9 $ 10,313.6 $ 10,037.5

Note 1 - Summary of Significa_3

Note 1 - Summary of Significant Accounting Policies (Details Textual) $ in Millions		3 Months Ended	9 Months Ended
	Jan. 19, 2024 USD ($)	Dec. 31, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Sep. 30, 2023 USD ($)
Number of Reportable Segments			3
Restricted Cash			$ 26.3	$ 19.7	$ 20.2
Payments to Acquire Businesses, Gross			$ 175.9	$ 37
MoGas Pipeline [Member]
Payments to Acquire Businesses, Gross	$ 176.1
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		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Regulated Operation [Member] | Spire Marketing [Member] | Spire Missouri [Member]
Purchases of natural gas from Spire Marketing	$ 0	$ 6.5	$ 10.6	$ 48.8
Transaction amount	1.4	0.3	1.7	0.4
Regulated Operation [Member] | Spire Marketing [Member] | Spire Alabama Inc [Member]
Purchases of natural gas from Spire Marketing	0	1.7	3.4	2.8
Unregulated Operation [Member] | Spire S T L Pipeline L L C [Member] | Spire Missouri [Member]
Transaction amount	7.9	8	24.4	23.9
Unregulated Operation [Member] | Spire MoGas Pipeline [Member] | Spire Missouri [Member]
Transaction amount	1.7	0	3.1	0
Unregulated Operation [Member] | Spire Storage Salt Plains LLC [Member] | Spire Missouri [Member]
Transaction amount	$ 0	$ 0	$ 0.7	$ 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	9 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Sep. 30, 2023
Accrued capital expenditures	$ 81.6	$ 62.2	$ 104.3
Spire Missouri [Member]
Accrued capital expenditures	43.5	33.4	56.5
Spire Alabama Inc [Member]
Accrued capital expenditures	$ 5.5	$ 4.5	$ 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		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Allowance at beginning of period	$ 39.1	$ 40.6	$ 32.5	$ 31.9
Provision for expected credit losses	5.6	1.2	17.6	13.5
Write-offs, net of recoveries	(11.5)	(7.1)	(16.9)	(10.7)
Allowance at end of period	33.2	34.7	33.2	34.7
Spire Missouri [Member]
Allowance at beginning of period	32	34.5	26.2	24.9
Provision for expected credit losses	4.7	0.3	14.5	11.4
Write-offs, net of recoveries	(10.1)	(6.1)	(14.1)	(7.6)
Allowance at end of period	26.6	28.7	26.6	28.7
Spire Alabama Inc [Member]
Allowance at beginning of period	6.2	5.3	5.7	6.3
Provision for expected credit losses	0.7	0.8	2.4	1.5
Write-offs, net of recoveries	(1.2)	(0.8)	(2.4)	(2.5)
Allowance at end of period	$ 5.7	$ 5.3	$ 5.7	$ 5.3

Note 2 - Revenue - Disaggregate

Note 2 - Revenue - Disaggregated of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Operating Revenues	$ 414.1	$ 418.5	$ 2,299.2	$ 2,355.9
Consolidation, Eliminations [Member]
Operating Revenues	(17.1)	(14.1)	(46.8)	(38.7)
Gas Utility [Member] | Operating Segments [Member]
Operating Revenues	372.7	387.8	2,160.6	2,175.3
Gas Marketing [Member] | Operating Segments [Member]
Operating Revenues	21.2	23.1	103.5	157.8
Midstream [Member] | Operating Segments [Member]
Operating Revenues	32.5	17.4	68.9	49.1
Other Operating Segment [Member] | Consolidation, Eliminations [Member]
Operating Revenues	4.8	4.3	13	12.4
Spire Missouri [Member]
Operating Revenues	248.8	253.8	1,550.7	1,586
Spire Missouri [Member] | Gas Utility [Member] | Operating Segments [Member]
Revenue	240.8	249.7	1,501.4	1,563.3
Changes in accrued revenue under alternative revenue programs	8	4.1	49.3	22.7
Spire Missouri [Member] | Gas Utility [Member] | Operating Segments [Member] | Residential [Member]
Revenue	169.5	171.7	1,091.2	1,142.3
Spire Missouri [Member] | Gas Utility [Member] | Operating Segments [Member] | Commercial and Industrial [Member]
Revenue	52.6	61.1	348.5	369.2
Spire Missouri [Member] | Gas Utility [Member] | Operating Segments [Member] | Transportation [Member]
Revenue	7.5	7.1	26.6	26.1
Spire Missouri [Member] | Gas Utility [Member] | Operating Segments [Member] | Off-system and Other Incentive [Member]
Revenue	7	6	23.4	15.6
Spire Missouri [Member] | Gas Utility [Member] | Operating Segments [Member] | Other Customer Revenue [Member]
Revenue	4.2	3.8	11.7	10.1
Spire Alabama Inc [Member]
Operating Revenues	103.5	113.1	505.1	483.8
Spire Alabama Inc [Member] | Gas Utility [Member] | Operating Segments [Member]
Revenue	103.7	111.3	510.3	483.9
Changes in accrued revenue under alternative revenue programs	(0.2)	1.8	(5.2)	(0.1)
Spire Alabama Inc [Member] | Gas Utility [Member] | Operating Segments [Member] | Residential [Member]
Revenue	53	56.7	306.7	288.1
Spire Alabama Inc [Member] | Gas Utility [Member] | Operating Segments [Member] | Commercial and Industrial [Member]
Revenue	26.9	32.7	130.4	127.8
Spire Alabama Inc [Member] | Gas Utility [Member] | Operating Segments [Member] | Transportation [Member]
Revenue	20.3	18.9	65.1	59
Spire Alabama Inc [Member] | Gas Utility [Member] | Operating Segments [Member] | Off-system and Other Incentive [Member]
Revenue	2.6	2.2	5.6	6.3
Spire Alabama Inc [Member] | Gas Utility [Member] | Operating Segments [Member] | Other Customer Revenue [Member]
Revenue	0.9	0.8	2.5	2.7
Spire [Member]
Operating Revenues	414.1	418.5	2,299.2	2,355.9
Spire [Member] | Operating Segments [Member]
Operating Revenues	431.2	432.6	2,346	2,394.6
Spire [Member] | Consolidation, Eliminations [Member]
Operating Revenues	(17.1)
Spire [Member] | Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment [Member]
Operating Revenues		(14.1)	(46.8)	(38.7)
Spire [Member] | Gas Utility [Member] | Operating Segments [Member]
Revenue	365.9	382.6	2,116.5	2,148.3
Changes in accrued revenue under alternative revenue programs	6.8	5.2	44.1	27
Total Gas Utility operating revenues	372.7	387.8	2,160.6	2,175.3
Spire [Member] | Gas Utility [Member] | Operating Segments [Member] | Residential [Member]
Revenue	232.2	238.1	1,454.5	1,486.3
Spire [Member] | Gas Utility [Member] | Operating Segments [Member] | Commercial and Industrial [Member]
Revenue	87.3	102.2	513.1	533.1
Spire [Member] | Gas Utility [Member] | Operating Segments [Member] | Transportation [Member]
Revenue	30.3	29	99.7	93.2
Spire [Member] | Gas Utility [Member] | Operating Segments [Member] | Off-system and Other Incentive [Member]
Revenue	9.6	8.2	29	21.9
Spire [Member] | Gas Utility [Member] | Operating Segments [Member] | Other Customer Revenue [Member]
Revenue	6.5	5.1	20.2	13.8
Spire [Member] | Gas Marketing [Member] | Operating Segments [Member]
Unregulated Operating Revenue	21.2	23.1	103.5	157.8
Spire [Member] | Midstream [Member] | Operating Segments [Member]
Unregulated Operating Revenue	32.5	17.4	68.9	49.1
Spire [Member] | Other Operating Segment [Member] | Operating Segments [Member]
Unregulated Operating Revenue	$ 4.8	$ 4.3	$ 13	$ 12.4

Note 2 - Revenue - Taxes Associ

Note 2 - Revenue - Taxes Associated with Natural Gas Utility Services (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Gross Receipts Tax Amounts	$ 22.4	$ 26	$ 113.5	$ 116.6
Spire Missouri [Member]
Gross Receipts Tax Amounts	16.3	18.9	82.8	86.6
Spire Alabama Inc [Member]
Gross Receipts Tax Amounts	$ 5.3	$ 6.1	$ 26.3	$ 25.5

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		9 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Net income		$ (12.6)	$ (21.6)	$ 276.8	$ 248.6
Provision for preferred dividends		3.7	3.7	11.1	11.1
(Loss) income allocated to participating securities		0	(0.1)	0.4	0.4
(Loss) Income Available to Common Shareholders		$ (16.3)	$ (25.2)	$ 265.3	$ 237.1
Basic (in shares)		57.7	52.5	55.6	52.5
Basic (Loss) Earnings Per Common Share (in dollars per share)		$ (0.28)	$ (0.48)	$ 4.77	$ 4.52
Dilutive Effect of forward sales of common stock, restricted stock and restricted stock units (in millions)* (in shares)	[1]	0	0	0.1	0.1
Weighted Average Diluted Common Shares (in millions) (in shares)		57.7	52.5	55.7	52.6
Diluted (Loss) Earnings Per Common Share (in dollars per share)		$ (0.28)	$ (0.48)	$ 4.76	$ 4.51
* 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 (in shares)		0.4	2.7	0.4	2.5
[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) - USD ($)			1 Months Ended	3 Months Ended		6 Months Ended
	Mar. 05, 2024	Dec. 11, 2023	Feb. 28, 2021	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2024	Mar. 01, 2024	Jan. 25, 2024
Parent Company [Member] | Two Thousand Twenty One Series A Zero Point Seven Five Percentage Remarketable Senior Notes [Member]
Debt Instrument, Face Amount			$ 1,000
Debt Instrument, Interest Rate, Stated Percentage			0.75%
Corporate Unit [Member] | Parent Company [Member]
Stock Issued During Period, Shares, New Issues (in shares)	2,745,733		3,500,000
Equity Units, Stated Value (in dollars per share)			$ 50
Percentage of Undivided Beneficial Ownership Interest			5%
Equity Units, Applicable Market Value (in dollars per share)							$ 58.6809
Equity Units, Number of Common Stock Obligated to be Purchased After Adjustment (in shares)							0.7845
Equity Stock Units Issued	$ 175,000,000
At The Market Program [Member]
Forward Sales Agreements, Shares Settled (in shares)		1,744,549				0
Proceeds from Shares Settled		$ 112,200,000
Sale of Stock, Maximum Aggregate Offering Price				$ 166,900,000		$ 166,900,000		$ 200,000,000
Forward Sales Agreements, Shares (in shares)				338,110	204,405
Forward Sales Agreements, Proceeds If Settled				$ 32,600,000		$ 32,600,000

Note 5 - Regulatory Matters (De

Note 5 - Regulatory Matters (Details Textual) - USD ($) $ in Millions									6 Months Ended	15 Months Ended
	Apr. 16, 2024	Jan. 01, 2024	Dec. 14, 2023	Dec. 13, 2023	Oct. 04, 2023	Apr. 30, 2023	Apr. 20, 2023	Jan. 01, 2023	Aug. 31, 2024	Apr. 16, 2024	Jun. 30, 2024
Spire Missouri [Member] | Missouri Public Service Commission [Member] | Infrastructure System Replacement Surcharge [Member]
Public Utilities, Approved Rate Increase (Decrease), Amount	$ 16.8				$ 12.4		$ 7.7			$ 36.9
Public Utilities, Requested Rate Increase (Decrease), Amount									$ 17.7
Spire Alabama Inc [Member] | Alabama Public Service Commission [Member]
Annual Revenue Increase From Rates, Amount		$ 14.3						$ 15
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	Jun. 30, 2024	Sep. 30, 2023	Jun. 30, 2023
Regulatory assets	$ 89.8	$ 348.3	$ 93.3
Regulatory Assets Noncurrent	1,282.8	1,249.2	1,421.2
Total Regulatory Assets	1,372.6	1,597.5	1,514.5
Regulatory Liability Current	37.9	7.3	5.5
Regulatory Liability Noncurrent	547.5	472.4	428.1
Total Regulatory Liabilities	585.4	479.7	433.6
Spire Missouri [Member]
Regulatory assets	63	293.1	35
Regulatory Assets Noncurrent	634.1	617.6	819.1
Total Regulatory Assets	697.1	910.7	854.1
Regulatory Liability Noncurrent	465.7	389.4	346.1
Total Regulatory Liabilities	465.7	389.4	346.1
Spire Alabama Inc [Member]
Regulatory assets	14.7	41.6	43.9
Regulatory Assets Noncurrent	626	606.9	576.7
Total Regulatory Assets	640.7	648.5	620.6
Regulatory Liability Current	32.2	0	0
Regulatory Liability Noncurrent	19.6	21.2	20.8
Total Regulatory Liabilities	51.8	21.2	20.8
Unamortized Purchased Gas Adjustments Asset [Member]
Regulatory assets	58	293.2	66.2
Regulatory Assets Noncurrent	0	23	206.3
Regulatory Liability Current	33.3	0	0
Regulatory Liability Noncurrent	83.6	11.2	0
Unamortized Purchased Gas Adjustments Asset [Member] | Spire Missouri [Member]
Regulatory assets	57.6	269.4	32.9
Regulatory Assets Noncurrent	0	23	206.3
Regulatory Liability Noncurrent	83.6	11.2	0
Unamortized Purchased Gas Adjustments Asset [Member] | Spire Alabama Inc [Member]
Regulatory assets	0	21.7	30.9
Regulatory Liability Current	32.2	0	0
Other Regulatory Assets (Liabilities) [Member]
Regulatory assets	31.8	55.1	27.1
Regulatory Assets Noncurrent	173.5	131.2	152.3
Regulatory Liability Current	4.6	7.3	5.5
Regulatory Liability Noncurrent	18.7	21.4	23.3
Other Regulatory Assets (Liabilities) [Member] | Spire Missouri [Member]
Regulatory assets	5.4	23.7	2.1
Regulatory Assets Noncurrent	159.7	116	136.5
Regulatory Liability Noncurrent	14.2	16.5	17.8
Other Regulatory Assets (Liabilities) [Member] | Spire Alabama Inc [Member]
Regulatory assets	14.7	19.9	13
Regulatory Assets Noncurrent	0.9	0.9	1
Regulatory Liability Noncurrent	3.2	3.3	3.5
Pension and Other Postretirement Plans Costs [Member]
Regulatory Assets Noncurrent	243.2	261	268.8
Regulatory Liability Noncurrent	192.3	185.2	165.3
Pension and Other Postretirement Plans Costs [Member] | Spire Missouri [Member]
Regulatory Assets Noncurrent	177.5	189.1	193.4
Regulatory Liability Noncurrent	165.7	156.5	137.9
Pension and Other Postretirement Plans Costs [Member] | Spire Alabama Inc [Member]
Regulatory Assets Noncurrent	62.3	67.8	71.1
Regulatory Liability Noncurrent	16.4	17.9	17.3
Deferred Income Tax Charge [Member]
Regulatory Assets Noncurrent	149	144.5	140.1
Deferred Income Tax Charge [Member] | Spire Missouri [Member]
Regulatory Assets Noncurrent	140.8	136.2	131.8
Deferred Income Tax Charge [Member] | Spire Alabama Inc [Member]
Regulatory Assets Noncurrent	1.8	2	2
Removal Costs [Member]
Regulatory Assets Noncurrent	658	633.2	597.9
Regulatory Liability Noncurrent	135.4	126.6	107.7
Removal Costs [Member] | Spire Missouri [Member]
Regulatory Assets Noncurrent	97	97	95.3
Regulatory Liability Noncurrent	97.1	90.4	72.3
Removal Costs [Member] | Spire Alabama Inc [Member]
Regulatory Assets Noncurrent	561	536.2	502.6
Renewable Energy Program [Member]
Regulatory Assets Noncurrent	59.1	56.3	55.8
Renewable Energy Program [Member] | Spire Missouri [Member]
Regulatory Assets Noncurrent	59.1	56.3	55.8
Estimated Deferred Taxes Due to Customers [Member]
Regulatory Liability Noncurrent	117.5	128	131.8
Estimated Deferred Taxes Due to Customers [Member] | Spire Missouri [Member]
Regulatory Liability Noncurrent	$ 105.1	$ 114.8	$ 118.1

Note 5 - Regulatory Matters -_2

Note 5 - Regulatory Matters - Regulatory Assets Not Earning a Return (Details) - USD ($) $ in Millions	Jun. 30, 2024	Sep. 30, 2023	Jun. 30, 2023
Regulatory assets not earning a return	$ 472.9	$ 672.5	$ 606.9
Spire Missouri [Member]
Regulatory assets not earning a return	466.6	666.2	600.7
Pension and Other Postretirement Plans Costs [Member]
Regulatory assets not earning a return	135.9	133.4	127.5
Pension and Other Postretirement Plans Costs [Member] | Spire Missouri [Member]
Regulatory assets not earning a return	135.9	133.4	127.5
Deferred Income Tax Charge [Member]
Regulatory assets not earning a return	147.1	142.5	138
Deferred Income Tax Charge [Member] | Spire Missouri [Member]
Regulatory assets not earning a return	140.8	136.2	131.8
Unamortized Purchased Gas Adjustments Asset [Member]
Regulatory assets not earning a return	57.6	292.4	239.2
Unamortized Purchased Gas Adjustments Asset [Member] | Spire Missouri [Member]
Regulatory assets not earning a return	57.6	292.4	239.2
Other Regulatory Assets (Liabilities) [Member]
Regulatory assets not earning a return	132.3	104.2	102.2
Other Regulatory Assets (Liabilities) [Member] | Spire Missouri [Member]
Regulatory assets not earning a return	$ 132.3	$ 104.2	$ 102.2

Note 6 - Financing (Details Tex

Note 6 - Financing (Details Textual) - USD ($) $ in Thousands					1 Months Ended
	Aug. 14, 2024	May 06, 2024	Apr. 05, 2024	Jan. 03, 2024	Feb. 29, 2024	Jul. 12, 2024	Jun. 30, 2024	Feb. 28, 2021
Remarketable Notes [Member]
Debt Instrument, Face Amount								$ 175,000
Debt Instrument, Interest Rate, Stated Percentage								0.75%
Senior Note [Member]
Debt Instrument, Face Amount					$ 175,000
Debt Instrument, Interest Rate, Stated Percentage					5.30%
Proceeds from Issuance of Debt					$ 173,500
Commercial Paper [Member] | Parent Company [Member]
Short Term Borrowings Used to Support Lending to Utilities							$ 476,700
Spire Missouri [Member] | First Mortgage Bond [Member] | Subsequent Event [Member]
Debt Instrument, Face Amount						$ 300,000
Debt Instrument, Redemption Price, Percentage	100%
Spire Missouri [Member] | Loans Payable [Member]
Debt Instrument, Face Amount				$ 200,000
Repayments of Debt		$ 150,000	$ 50,000
Spire Missouri [Member] | Loans Payable [Member] | Secured Overnight Financing Rate (SOFR) [Member]
Debt Instrument, Basis Spread on Variable Rate				0.10%
Spire Missouri [Member] | Loans Payable [Member] | Adjusted SOFR [Member[
Debt Instrument, Basis Spread on Variable Rate				0.90%
Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity							$ 1,300,000
Line of Credit Facility, Covenant, Percentage of Total Capitalization							60%
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	9 Months Ended
	Jun. 30, 2024	Sep. 30, 2023	Jun. 30, 2023
Highest borrowings outstanding	$ 1,275
Lowest borrowings outstanding	741
Weighted average borrowings	$ 944.9
Weighted average interest rate	5.70%
Borrowings outstanding	$ 771	$ 955.5	$ 557.6
Weighted average interest rate	5.60%	5.60%	5.50%
Term Loan [Member] | Spire Missouri [Member]
Highest borrowings outstanding	$ 200
Lowest borrowings outstanding	0
Weighted average borrowings	$ 84.9
Weighted average interest rate	6.40%
Borrowings outstanding	$ 0	$ 0	$ 0
Weighted average interest rate	0%	0%	0%
Spire Note [Member] | Spire Alabama Inc [Member]
Highest borrowings outstanding	$ 132.5
Lowest borrowings outstanding	5.5
Weighted average borrowings	$ 68.8
Weighted average interest rate	5.70%
Borrowings outstanding	$ 23	$ 124.1	$ 108.1
Weighted average interest rate	5.60%	5.60%	5.50%
Spire Note [Member] | Spire Missouri [Member]
Highest borrowings outstanding	$ 643.6
Lowest borrowings outstanding	228.5
Weighted average borrowings	$ 431.9
Weighted average interest rate	5.60%
Borrowings outstanding	$ 418.3	$ 540.6	$ 228.1
Weighted average interest rate	5.60%	5.60%	5.50%
Parent Company [Member] | Commercial Paper [Member]
Highest borrowings outstanding	$ 1,135
Lowest borrowings outstanding	554.6
Weighted average borrowings	$ 860
Weighted average interest rate	5.70%
Borrowings outstanding	$ 771	$ 955.5	$ 557.6
Weighted average interest rate	5.60%	5.60%	5.50%

Note 6 - Financing - Capitalize

Note 6 - Financing - Capitalized Interest Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Interest Paid Capitalized	$ 4.3	$ 2.3	$ 12.1	$ 5.8
Spire Missouri [Member]
Interest Paid Capitalized	1.2	1	3.5	2.1
Spire Alabama Inc [Member]
Interest Paid Capitalized	$ 0.3	$ 0.5	$ 1.1	$ 1.8

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	Jun. 30, 2024	Sep. 30, 2023	Jun. 30, 2023
Reported Value Measurement [Member]
Cash and cash equivalents	$ 7.4	$ 5.6	$ 5.3
Notes payable	771	955.5	557.6
Long-term debt, including current portion	3,729.3	3,710.6	3,959.9
Reported Value Measurement [Member] | Spire Missouri [Member]
Cash and cash equivalents	1.3	0.8
Long-term debt, including current portion	1,786.6	1,785.4	2,035.1
Notes payable – associated companies	418.3	540.6	228.1
Reported Value Measurement [Member] | Spire Alabama Inc [Member]
Cash and cash equivalents	2.3	1.2	0.5
Long-term debt, including current portion	746.2	745.9	745.8
Notes payable – associated companies	23	124.1	108.1
Estimate of Fair Value Measurement [Member]
Cash and cash equivalents	7.4	5.6	5.3
Notes payable	771	955.5	557.6
Long-term debt, including current portion	3,407.1	3,270.2	3,650.7
Estimate of Fair Value Measurement [Member] | Spire Missouri [Member]
Cash and cash equivalents	1.3	0.8
Long-term debt, including current portion	1,626.3	1,592.4	1,890.2
Notes payable – associated companies	418.3	540.6	228.1
Estimate of Fair Value Measurement [Member] | Spire Alabama Inc [Member]
Cash and cash equivalents	2.3	1.2	0.5
Long-term debt, including current portion	674.4	648	681.5
Notes payable – associated companies	23	124.1	108.1
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	7.4	5.6	5.3
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	1.3	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	2.3	1.2	0.5
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	771	955.5	557.6
Long-term debt, including current portion	3,407.1	3,270.2	3,650.7
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Spire Missouri [Member]
Cash and cash equivalents	0	0
Long-term debt, including current portion	1,626.3	1,592.4	1,890.2
Notes payable – associated companies	418.3	540.6	228.1
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Spire Alabama Inc [Member]
Cash and cash equivalents	0	0	0
Long-term debt, including current portion	674.4	648	681.5
Notes payable – associated companies	$ 23	$ 124.1	$ 108.1

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	Jun. 30, 2024	Sep. 30, 2023	Jun. 30, 2023
Derivative Asset Fair Value Gross Asset	$ 154.3	$ 135.3	$ 110.4
Effects of netting, asset	(13.7)	(20.1)	(11.5)
Derivative Liability Fair Value Gross Liability	27	30.8	34.7
Effects of netting, liability	(46.4)	(69.4)	(70.8)
Fair Value, Inputs, Level 1 [Member]
Derivative Asset Fair Value Gross Asset	81.9	74.4	63.3
Derivative Liability Fair Value Gross Liability	43.6	72.6	69.8
Fair Value, Inputs, Level 2 [Member]
Derivative Asset Fair Value Gross Asset	86.1	81	58.6
Derivative Liability Fair Value Gross Liability	29.8	27.6	35.7
U S Stock And Bond Mutual Funds [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	24.5	20.4	21.4
Effects of netting, asset	0	0	0
U S Stock And Bond Mutual Funds [Member] | Other Operating Segment [Member]
Derivative Asset Fair Value Gross Asset	30.7	37.6	31.4
Effects of netting, asset	0	0	0
U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	24.5	20.4	21.4
U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member] | Other Operating Segment [Member]
Derivative Asset Fair Value Gross Asset	30.7	37.6	31.4
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	0
U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 2 [Member] | Other Operating Segment [Member]
Derivative Asset Fair Value Gross Asset	0	0	0
N Y M E X I C E Natural Gas Contracts [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset			0
Effects of netting, asset			(44.8)
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			(10.5)
Derivative Liability Fair Value Gross Liability			0
Effects of netting, liability			(24.3)
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			44.8
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			10.5
Derivative Liability Fair Value Gross Liability			24.3
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
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
N Y M E X And I C E Natural Gas Contracts [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset	0	0
Effects of netting, asset	(4.8)	(6.3)
Derivative Liability Fair Value Gross Liability	0	6.8
Effects of netting, liability	(21)	(44)
N Y M E X And I C E Natural Gas Contracts [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	0	0
Effects of netting, asset	(6.1)	(10.1)
Derivative Liability Fair Value Gross Liability	0	0
Effects of netting, liability	(22.6)	(21.8)
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	4.8	6.3
Derivative Liability Fair Value Gross Liability	21	50.8
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	6.1	10.1
Derivative Liability Fair Value Gross Liability	22.6	21.8
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	0
Derivative Liability Fair Value Gross Liability	0	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	0
Derivative Liability Fair Value Gross Liability	0	0
Gasoline And Heating Oil Contracts [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset			0
Effects of netting, asset			(0.7)
Derivative Liability Fair Value Gross Liability		0
Effects of netting, liability		(0.1)
Gasoline And Heating Oil Contracts [Member] | Fair Value, Inputs, Level 1 [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset			0.7
Derivative Liability Fair Value Gross Liability		0
Gasoline And Heating Oil Contracts [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Utility [Member]
Derivative Asset Fair Value Gross Asset			0
Derivative Liability Fair Value Gross Liability		0.1
Natural Gas Commodity Contracts [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	51.1	33.1	34.8
Effects of netting, asset	(2.8)	(3.6)	(1)
Derivative Liability Fair Value Gross Liability	27	24	33.9
Effects of netting, liability	(2.8)	(3.6)	(1)
Natural Gas Commodity Contracts [Member] | Fair Value, Inputs, Level 1 [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	0	0	0
Derivative Liability Fair Value Gross Liability	0	0	0
Natural Gas Commodity Contracts [Member] | Fair Value, Inputs, Level 2 [Member] | Gas Marketing [Member]
Derivative Asset Fair Value Gross Asset	53.9	36.7	35.8
Derivative Liability Fair Value Gross Liability	29.8	27.6	34.9
U.S. Bonds [Member] | Other Operating Segment [Member]
Derivative Asset Fair Value Gross Asset	14.4
Effects of netting, asset	0
U.S. Bonds [Member] | Fair Value, Inputs, Level 1 [Member] | Other Operating Segment [Member]
Derivative Asset Fair Value Gross Asset	14.4
U.S. Bonds [Member] | Fair Value, Inputs, Level 2 [Member] | Other Operating Segment [Member]
Derivative Asset Fair Value Gross Asset	0
Global Bonds [Member] | Other Operating Segment [Member]
Derivative Asset Fair Value Gross Asset	1.4
Effects of netting, asset	0
Global Bonds [Member] | Fair Value, Inputs, Level 1 [Member] | Other Operating Segment [Member]
Derivative Asset Fair Value Gross Asset	1.4
Global Bonds [Member] | Fair Value, Inputs, Level 2 [Member] | Other Operating Segment [Member]
Derivative Asset Fair Value Gross Asset	0
Interest Rate Swap [Member] | Other Operating Segment [Member]
Derivative Asset Fair Value Gross Asset	32.2	44.2	22.8	[1]
Effects of netting, asset	0	0	0
Derivative Liability Fair Value Gross Liability			0.8
Effects of netting, liability			0
Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member] | Other Operating Segment [Member]
Derivative Asset Fair Value Gross Asset	0	0	0	[1]
Derivative Liability Fair Value Gross Liability			0
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member] | Other Operating Segment [Member]
Derivative Asset Fair Value Gross Asset	32.2	44.2	22.8	[1]
Derivative Liability Fair Value Gross Liability			0.8
Spire Missouri [Member]
Derivative Asset Fair Value Gross Asset	24.5	20.4	0
Effects of netting, asset	(4.8)	(6.4)	(45.5)
Spire Missouri [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative Asset Fair Value Gross Asset	29.3	26.7	45.5
Spire Missouri [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative Asset Fair Value Gross Asset	0	0.1	0
Spire Missouri [Member] | U S Stock And Bond Mutual Funds [Member]
Derivative Asset Fair Value Gross Asset	24.5	20.4	21.4
Effects of netting, asset	0	0	0
Spire Missouri [Member] | U S Stock And Bond Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative Asset Fair Value Gross Asset	24.5	20.4	21.4
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
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	(4.8)	(6.3)	(44.8)
Derivative Liability Fair Value Gross Liability	0	6.8
Effects of netting, liability	(21)	(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	4.8	6.3	44.8
Derivative Liability Fair Value Gross Liability	21	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
Effects of netting, asset		(0.1)	(0.7)
Derivative Liability Fair Value Gross Liability		0
Spire Missouri [Member] | Gasoline And Heating Oil Contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative Asset Fair Value Gross Asset			0.7
Derivative Liability Fair Value Gross Liability		0
Spire Missouri [Member] | Gasoline And Heating Oil Contracts [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative Asset Fair Value Gross Asset			$ 0
Derivative Liability Fair Value Gross Liability		$ 0.1
[1]Subsequent to the issuance of its consolidated financial statements for the quarter ended March 31, 2023, during the fourth quarter of fiscal 2023, the Company identified an error in the fair value level presentation for certain line items in the Fair Value Measurements table. The presentaion has been corrected to reflect the impacted line items in Level 2 rather than Level 1 as of March 31, 2023. This immaterial correction 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		9 Months Ended
	Dec. 26, 2022	Dec. 23, 2021	Dec. 22, 2021	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Sep. 30, 2023
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Settlement							$ 0
Regulatory Asset, Total				$ 1,372,600	$ 1,514,500	$ 1,372,600	1,514,500	$ 1,597,500
Regulatory Liability				585,400	433,600	585,400	433,600	$ 479,700
Pension Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement				$ (1,000)	0	$ (1,000)	(8,600)
Spire Missouri [Member]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate				5.70%		5.70%		6.25%
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Settlement				$ 2,600
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement				(1,000)
Regulatory Asset, Total				697,100	854,100	$ 697,100	854,100	$ 910,700
Regulatory Liability				465,700	346,100	465,700	346,100	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]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement				(1,000)	0	(1,000)	0
Spire Missouri [Member] | Pension Plan [Member] | Qualified Plan [Member]
Defined Benefit Plan, Plan Assets, Contributions by Employer						10,000
Anticipated Contributions to Pension Plans Qualified Trusts						11,600
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
Spire Alabama Inc [Member]
Regulatory Asset, Total				640,700	620,600	640,700	620,600	648,500
Regulatory Liability				$ 51,800	$ 20,800	51,800	$ 20,800	$ 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, Plan Assets, Contributions by Employer						8,000
Anticipated Contributions to Pension Plans Qualified Trusts						8,400
Spire Alabama Inc [Member] | Two Plans [Member]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate								5.70%
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%		5.60%
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%		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

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		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Spire Missouri [Member]
Loss on lump-sum settlements	$ 1
Pension Plan [Member]
Service cost – benefits earned during the period	3.9	$ 4.2	$ 11.8	$ 12.2
Interest cost on projected benefit obligation	6.6	6.6	20	18.9
Expected return on plan assets	(6.3)	(6.4)	(18.7)	(18.5)
Amortization of prior service credit	(1.1)	(1.1)	(3.4)	(3.4)
Amortization of actuarial loss	1.6	1.5	4.8	4.7
Loss on lump-sum settlements	1	0	1	8.6
Subtotal	5.7	4.8	15.5	22.5
Regulatory adjustment	8.8	6.1	26.3	18.3
Net pension cost	14.5	10.9	41.8	40.8
Pension Plan [Member] | Spire Missouri [Member]
Service cost – benefits earned during the period	2.6	2.8	7.8	8.5
Interest cost on projected benefit obligation	4.7	4.5	14.2	13.4
Expected return on plan assets	(4.3)	(4.5)	(12.8)	(13.5)
Amortization of prior service credit	(0.5)	(0.5)	(1.5)	(1.5)
Amortization of actuarial loss	1.5	1.5	4.4	4.6
Loss on lump-sum settlements	1	0	1	0
Subtotal	5	3.8	13.1	11.5
Regulatory adjustment	6.2	3.4	18.8	19.6
Net pension cost	11.2	7.2	31.9	31.1
Pension Plan [Member] | Spire Alabama Inc [Member]
Service cost – benefits earned during the period	1.2	1.3	3.5	3.2
Interest cost on projected benefit obligation	1.3	1.5	3.8	3.6
Expected return on plan assets	(1.2)	(1.1)	(3.6)	(2.7)
Amortization of prior service credit	(0.6)	(0.6)	(1.8)	(1.8)
Amortization of actuarial loss	0.2	0.1	0.7	0.4
Subtotal	0.9	1.2	2.6	11.3
Regulatory adjustment	2.3	2.4	6.8	(2)
Net pension cost	3.2	3.6	9.4	9.3
Other Postretirement Benefits Plan [Member]
Service cost – benefits earned during the period	1.2	1.2	3.3	3.6
Interest cost on projected benefit obligation	2.1	2	6.6	6.3
Expected return on plan assets	(3.7)	(4)	(11.9)	(11.8)
Amortization of prior service credit	0	0.1	0.2	0.2
Amortization of actuarial loss	(1.2)	(0.9)	(3.3)	(3)
Subtotal	(1.6)	(1.6)	(5.1)	(4.7)
Regulatory adjustment	0.1	(0.5)	0.6	(0.2)
Net pension cost	(1.5)	(2.1)	(4.5)	(4.9)
Other Postretirement Benefits Plan [Member] | Spire Missouri [Member]
Service cost – benefits earned during the period	0.9	1	2.7	3
Interest cost on projected benefit obligation	1.6	1.6	4.9	4.9
Expected return on plan assets	(2.5)	(2.6)	(7.9)	(7.9)
Amortization of prior service credit	0.1	0.1	0.4	0.4
Amortization of actuarial loss	(1)	(0.8)	(2.8)	(2.4)
Subtotal	(0.9)	(0.7)	(2.7)	(2)
Regulatory adjustment	0.6	(0.2)	1.9	1.1
Net pension cost	(0.3)	(0.9)	(0.8)	(0.9)
Other Postretirement Benefits Plan [Member] | Spire Alabama Inc [Member]
Service cost – benefits earned during the period	0.2	0.2	0.5	0.5
Interest cost on projected benefit obligation	0.5	0.4	1.6	1.3
Expected return on plan assets	(1.2)	(1.3)	(3.8)	(3.8)
Amortization of prior service credit	(0.1)	0	(0.2)	(0.2)
Amortization of actuarial loss	0	(0.1)	(0.1)	(0.4)
Subtotal	(0.6)	(0.8)	(2)	(2.6)
Regulatory adjustment	(0.5)	(0.5)	(1.4)	(1.4)
Net pension cost	$ (1.1)	$ (1.3)	$ (3.4)	$ (4)

Note 10 - Information by Oper_3

Note 10 - Information by Operating Segment (Details Textual)	9 Months Ended
	Jun. 30, 2024
Number of Reportable Segments	3

Note 10 - Information by Oper_4

Note 10 - Information by Operating Segment - Segment Information by Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenues from external customers	$ 414.1	$ 418.5	$ 2,299.2	$ 2,355.9
Intersegment revenues	0	0	0	0
Operating Revenues	414.1	418.5	2,299.2	2,355.9
Depreciation and amortization	71.4	64.3	207.3	189
Interest Expense, Net	48.8	46.7	151.6	137.5
Income Tax (Benefit) Expense	(3.1)	(6.8)	67.3	55.7
Net economic (loss) earnings	(4.3)	(18.6)	275	265.7
Capital expenditures	222.2	175.5	631.5	483.3
Consolidation, Eliminations [Member]
Revenues from external customers	0	0	0	0
Intersegment revenues	(17.1)	(14.1)	(46.8)	(38.7)
Operating Revenues	(17.1)	(14.1)	(46.8)	(38.7)
Depreciation and amortization	0	0	0	0
Interest Expense, Net	(10.1)	(6.9)	(34.7)	(24)
Income Tax (Benefit) Expense	0	0	0	0
Net economic (loss) earnings	0	0	0	0
Capital expenditures	(0.1)	0	(1)	0
Gas Utility [Member] | Operating Segments [Member]
Revenues from external customers	371.3	387.5	2,158.9	2,174.9
Intersegment revenues	1.4	0.3	1.7	0.4
Operating Revenues	372.7	387.8	2,160.6	2,175.3
Depreciation and amortization	66.7	61.7	196.3	181.6
Interest Expense, Net	34.9	35.6	112.2	103.2
Income Tax (Benefit) Expense	(0.9)	(3.6)	56.5	47.7
Net economic (loss) earnings	(11)	(12.3)	252.8	234.5
Capital expenditures	189.2	149.1	501.4	439.1
Gas Marketing [Member] | Operating Segments [Member]
Revenues from external customers	21.2	23.1	103.5	157.8
Intersegment revenues	0	0	0	0
Operating Revenues	21.2	23.1	103.5	157.8
Depreciation and amortization	0.3	0.3	1.1	1
Interest Expense, Net	0	0	0	0
Income Tax (Benefit) Expense	(1.1)	(1.7)	10.3	9.6
Net economic (loss) earnings	1	(2.5)	23.7	45
Capital expenditures	0	0	0	0.2
Midstream [Member] | Operating Segments [Member]
Revenues from external customers	21.3	7.7	36.3	22.7
Intersegment revenues	11.2	9.7	32.6	26.4
Operating Revenues	32.5	17.4	68.9	49.1
Depreciation and amortization	4.2	2.1	9.5	6
Interest Expense, Net	1.7	2.3	5.5	6.1
Income Tax (Benefit) Expense	3.6	1.2	5.7	4.1
Net economic (loss) earnings	13.9	3.6	20.1	11.6
Capital expenditures	33.1	26.6	131.1	43.6
Other Operating Segment [Member]
Depreciation and amortization	0.2	0.2	0.4	0.4
Interest Expense, Net	22.3	15.7	68.6	52.2
Income Tax (Benefit) Expense	(4.7)	(2.7)	(5.2)	(5.7)
Other Operating Segment [Member] | Consolidation, Eliminations [Member]
Revenues from external customers	0.3	0.2	0.5	0.5
Intersegment revenues	4.5	4.1	12.5	11.9
Operating Revenues	4.8	4.3	13	12.4
Net economic (loss) earnings	(8.2)	(7.4)	(21.6)	(25.4)
Capital expenditures	$ 0	$ (0.2)	$ 0	$ 0.4

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		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Net income	$ (12.6)	$ (21.6)	$ 276.8	$ 248.6
Fair value and timing adjustments	6.2	3.4	(9.2)	22.2
Acquisition and restructuring activities	4.8	0.5	6.7	0.5
Income tax adjustments	(2.7)	(0.9)	0.7	(5.6)
Net Economic (Loss) Earnings	$ (4.3)	$ (18.6)	$ 275	$ 265.7

Note 10 - Information by Oper_6

Note 10 - Information by Operating Segment - Total Assets by Segment (Details) - USD ($) $ in Millions	Jun. 30, 2024	Sep. 30, 2023	Jun. 30, 2023
Total Assets	$ 10,710.9	$ 10,313.6	$ 10,037.5
Operating Segments [Member] | Gas Utility [Member]
Total Assets	8,601.9	8,486.7	8,283.2
Operating Segments [Member] | Gas Marketing [Member]
Total Assets	212.3	332	316.6
Operating Segments [Member] | Midstream [Member]
Total Assets	871.9	574.3	533.3
Operating Segments [Member] | Other Operating Segment [Member]
Total Assets	2,627.4	2,533.3	2,134.1
Consolidation, Eliminations [Member]
Total Assets	$ (1,602.6)	$ (1,612.7)	$ (1,229.7)

Note 11 - Commitments and Con_2

Note 11 - Commitments and Contingencies (Details Textual) $ in Millions	9 Months Ended
	Jun. 30, 2024 USD ($)
Long-Term Purchase Commitment, Amount	$ 1,654.7
Capital Committed to Contribute to Partnership	25.3
Remaining Unfunded Capital Commitment	19.5
Spire Missouri [Member]
Long-Term Purchase Commitment, Amount	1,573.7
Spire Alabama Inc [Member]
Long-Term Purchase Commitment, Amount	$ 405.7