Spire Alabama 10-Q 4 Feb 21 2021 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Dec. 31, 2020	Jan. 31, 2021
Entity Information [Line Items]
Entity Registrant Name	Spire Inc
Entity Central Index Key	0001126956
Current Fiscal Year End Date	--09-30
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 Common Stock, Shares Outstanding (in shares)		51,664,553
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Document Type	10-Q
Amendment Flag	false
Entity Shell Company	false
Entity File Number	1-16681
Entity Tax Identification Number	74-2976504
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
Document Quarterly Report	true
Document Transition Report	false
Spire Missouri Inc
Entity Information [Line Items]
Entity Registrant Name	Spire Missouri Inc
Entity Central Index Key	0000057183
Current Fiscal Year End Date	--09-30
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 Common Stock, Shares Outstanding (in shares)		24,577
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Document Type	10-Q
Amendment Flag	false
Entity Shell Company	false
Entity File Number	1-1822
Entity Tax Identification Number	43-0368139
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
Spire Alabama Inc
Entity Information [Line Items]
Entity Registrant Name	Spire Alabama Inc
Entity Central Index Key	0000003146
Current Fiscal Year End Date	--09-30
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 Common Stock, Shares Outstanding (in shares)		1,972,052
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Document Type	10-Q
Amendment Flag	false
Entity Shell Company	false
Entity File Number	2-38960
Entity Tax Identification Number	63-0022000
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
Common Stock $1.00 par value
Entity Information [Line Items]
Trading Symbol	SR
Title of each class	Common Stock $1.00 par value
Name of each exchange on which registered	NYSE
Depositary Shares, each representing a 1/1,000th interest in a share of 5.90% Series A Cumulative Redeemable Perpetual Preferred Stock, par value $25.00 per share
Entity Information [Line Items]
Trading Symbol	SR.PRA
Title of each class	Depositary Shares
Name of each exchange on which registered	NYSE

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating Revenues	$ 512.6	$ 566.9
Operating Expenses:
Natural gas	181.2	261.9
Operation and maintenance	111.6	116.6
Depreciation and amortization	50.8	47.5
Taxes, other than income taxes	36.1	38.6
Total Operating Expenses	379.7	464.6
Operating Income	132.9	102.3
Interest Expense, Net	25.7	26.7
Other Income, Net	4.3	5.7
Income Before Income Taxes	111.5	81.3
Income Tax Expense	22.6	14.3
Net Income	88.9	67
Provision for preferred dividends	3.7	3.7
Income allocated to participating securities	0.1	0.1
Net Income Available to Common Shareholders	$ 85.1	$ 63.2
Weighted Average Number of Common Shares Outstanding:
Basic	51.5	50.9
Diluted	51.6	51.1
Basic Earnings Per Common Share	$ 1.65	$ 1.24
Diluted Earnings Per Common Share	$ 1.65	$ 1.24
Spire Alabama
Operating Revenues	$ 113.6	$ 126.2
Operating Expenses:
Natural gas	35.1	47
Operation and maintenance	32.8	35.2
Depreciation and amortization	15	14.3
Taxes, other than income taxes	8.2	8.8
Total Operating Expenses	91.1	105.3
Operating Income	22.5	20.9
Interest Expense, Net	4.7	5.4
Other Income, Net	0.7	2.2
Income Before Income Taxes	18.5	17.7
Income Tax Expense	4.8	4.5
Net Income	$ 13.7	$ 13.2

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Net Income	$ 88.9	$ 67
Cash flow hedging derivative instruments:
Net hedging gain arising during the period	17.2	18.9
Amounts reclassified into net income	(0.3)	(0.3)
Net gain on cash flow hedging derivative instruments	16.9	18.6
Other Comprehensive Income, Before Tax	16.9	18.6
Income Tax Expense Related to Items of Other Comprehensive Income	3.8	4.2
Other Comprehensive Income, Net of Tax	13.1	14.4
Comprehensive Income	102	81.4
Operating Revenues	512.6	566.9
Operating Expenses:
Natural gas	181.2	261.9
Operation and maintenance	111.6	116.6
Depreciation and amortization	50.8	47.5
Taxes, other than income taxes	36.1	38.6
Total Operating Expenses	379.7	464.6
Operating Income	132.9	102.3
Interest Expense, Net	25.7	26.7
Other Income, Net	4.3	5.7
Income Before Income Taxes	111.5	81.3
Income Tax Expense	22.6	14.3
Spire Missouri
Net Income	56.6	48
Cash flow hedging derivative instruments:
Other Comprehensive Income, Net of Tax	0.1	0.1
Comprehensive Income	56.7	48.1
Operating Revenues	355.5	374
Operating Expenses:
Natural gas	161.6	185.8
Operation and maintenance	62.9	65.5
Depreciation and amortization	30.4	29
Taxes, other than income taxes	25.1	26.7
Total Operating Expenses	280	307
Operating Income	75.5	67
Interest Expense, Net	11.7	13.2
Other Income, Net	2.7	1
Income Before Income Taxes	66.5	54.8
Income Tax Expense	$ 9.9	$ 6.8

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Millions	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
ASSETS
Utility Plant	$ 6,860.2	$ 6,766.3	$ 6,256.1
Less: Accumulated depreciation and amortization	2,113.3	2,086.2	1,823.8
Net Utility Plant	4,746.9	4,680.1	4,432.3
Non-utility Property (net of accumulated depreciation and amortization of $22.2, $19.0 and $13.9 at December 31, 2020, September 30, 2020, and December 31, 2019, respectively)	448.7	432.3	518.7
Other Investments	74.8	71.7	74.7
Total Other Property and Investments	523.5	504	593.4
Current Assets:
Cash and cash equivalents	3.5	4.1	21.5
Accounts receivable:
Utility	281.5	131.8	282
Other	170.4	146.4	195.6
Allowance for credit losses	(28.9)	(24.9)	(26.3)
Delayed customer billings	13.6	10	6.6
Inventories:
Natural gas	145.9	154.3	149.1
Propane gas	10.7	10.7	10.7
Materials and supplies	27.9	26.5	25.8
Regulatory assets	70.5	69.5	67.9
Prepayments	30.8	29.2	30.8
Other	44.1	33	12.7
Total Current Assets	770	590.6	776.4
Deferred Charges and Other Assets:
Goodwill	1,171.6	1,171.6	1,171.6
Regulatory assets	1,079.2	1,069.4	750.5
Other	224.4	225.5	236.8
Total Deferred Charges and Other Assets	2,475.2	2,466.5	2,158.9
Total Assets	8,515.6	8,241.2	7,961
Capitalization:
Preferred stock ($25.00 par value per share; 10.0 million depositary shares authorized, issued and outstanding at December 31, 2020, September 30, 2020, and December 31, 2019)	242	242	242
Common stock (par value $1.00 per share; 70.0 million shares authorized; 51.7 million, 51.6 million, and 51.1 million shares issued and outstanding at December 31, 2020, September 30, 2020, and December 31, 2019, respectively)	51.7	51.6	51.1
Paid-in capital and common stock	1,550	1,549.2	1,506.7
Retained earnings	771.2	720.7	803.1
Accumulated other comprehensive loss	(28.1)	(41.2)	(16.9)
Total Shareholders' Equity	2,586.8	2,522.3	2,586
Temporary equity	5.3	3.4	4.1
Long-term debt (less current portion)	2,517.6	2,423.7	2,484.4
Total Capitalization	5,109.7	4,949.4	5,074.5
Current Liabilities:
Current portion of long-term debt	110.8	60.4	45.3
Notes payable	696.1	648	518.9
Accounts payable	260.8	243.3	307.9
Advance customer billings	43.2	45.3	31.4
Wages and compensation accrued	26.7	46.3	35.4
Customer deposits	30.9	30.6	36.5
Taxes accrued	41.2	71.4	43.8
Regulatory liabilities	95.5	113	50
Other	241.5	190.9	183.3
Total Current Liabilities	1,546.7	1,449.2	1,252.5
Deferred Credits and Other Liabilities:
Deferred income taxes	541.9	511.4	475.3
Pension and postretirement benefit costs	289.2	309	260.7
Asset retirement obligations	545.6	540.1	340.9
Regulatory liabilities	357.3	343.7	417.8
Other	125.2	138.4	139.3
Total Deferred Credits and Other Liabilities	1,859.2	1,842.6	1,634
Commitments and Contingencies (Note 10)
Total Capitalization and Liabilities	8,515.6	8,241.2	7,961
Spire Missouri
ASSETS
Utility Plant	4,012.8	3,931.2	3,718.9
Less: Accumulated depreciation and amortization	851.5	825.7	780.1
Net Utility Plant	3,161.3	3,105.5	2,938.8
Other Investments	59	56.7	56.8
Current Assets:
Cash and cash equivalents	0	0	9.3
Accounts receivable:
Utility	195.4	92.5	193.8
Associated companies	2.3	2.7	4.8
Other	23.6	34.1	23.7
Allowance for credit losses	(21.4)	(18.1)	(17.9)
Delayed customer billings	5.1	2.4	6.6
Inventories:
Natural gas	88.3	95.1	92.7
Propane gas	10.7	10.7	10.7
Materials and supplies	16.1	15.6	15.2
Regulatory assets	32.1	32.1	29.4
Prepayments	20.9	20.7	17.8
Total Current Assets	373.1	287.8	386.1
Deferred Charges and Other Assets:
Goodwill	210.2	210.2	210.2
Regulatory assets	550.4	548.7	491.1
Other	96.1	96	88.1
Total Deferred Charges and Other Assets	856.7	854.9	789.4
Total Assets	4,450.1	4,304.9	4,171.1
Capitalization:
Paid-in capital and common stock	765.1	765.1	765.1
Retained earnings	729.5	672.9	613.3
Accumulated other comprehensive loss	(2.8)	(2.9)	(2.3)
Total Shareholders' Equity	1,491.8	1,435.1	1,376.1
Long-term debt (less current portion)	1,092.2	1,092	1,098.6
Total Capitalization	2,584	2,527.1	2,474.7
Current Liabilities:
Notes payable – associated companies	393.7	301.2	288.1
Accounts payable	82.6	66.7	76.3
Accounts payable – associated companies	7.1	9.3	11.2
Advance customer billings	29.8	32.7	20.7
Wages and compensation accrued	19.5	33.3	25
Customer deposits	9	9.3	13.6
Taxes accrued	13.4	39.1	14.6
Regulatory liabilities	83.4	103.2	42.4
Other	82.6	39.9	65.7
Total Current Liabilities	721.1	634.7	557.6
Deferred Credits and Other Liabilities:
Deferred income taxes	449.4	434.7	376.2
Pension and postretirement benefit costs	198.7	217.2	189.3
Asset retirement obligations	155	153.4	175.3
Regulatory liabilities	288.2	274.8	345.5
Other	53.7	63	52.5
Total Deferred Credits and Other Liabilities	1,145	1,143.1	1,138.8
Commitments and Contingencies (Note 10)
Total Capitalization and Liabilities	4,450.1	4,304.9	4,171.1
Spire Alabama
ASSETS
Utility Plant	2,487.4	2,469.9	2,174.1
Less: Accumulated depreciation and amortization	1,122.8	1,117	894.2
Net Utility Plant	1,364.6	1,352.9	1,279.9
Accounts receivable:
Utility	69.6	31.4	71.6
Associated companies	0.7	0.6	0.2
Other	6.1	5.8	8.7
Allowance for credit losses	(6.2)	(5.5)	(7.4)
Delayed customer billings	8.5	7.5	0
Inventories:
Natural gas	23.8	22.5	30.6
Materials and supplies	9.2	8.4	8.1
Regulatory assets	22.7	20.4	24.4
Prepayments	5.5	4.3	6.6
Other	0.1	0.2	0.4
Total Current Assets	140	95.6	143.2
Deferred Charges and Other Assets:
Regulatory assets	498.2	489.9	230.2
Deferred income taxes	54.5	59.3	76.8
Other	53.5	53.7	62.5
Total Deferred Charges and Other Assets	606.2	602.9	369.5
Total Assets	2,110.8	2,051.4	1,792.6
Capitalization:
Paid-in capital and common stock	339.9	350.9	370.9
Retained earnings	509	500.8	466.3
Total Shareholders' Equity	848.9	851.7	837.2
Long-term debt (less current portion)	571	471.8	471.7
Total Capitalization	1,419.9	1,323.5	1,308.9
Current Liabilities:
Current portion of long-term debt	50	0	40
Notes payable – associated companies	27	121.3	67.1
Accounts payable	40	43.7	51.9
Accounts payable – associated companies	5.3	4.2	3.2
Advance customer billings	12.5	11.5	10
Wages and compensation accrued	4.2	8	6.5
Customer deposits	19.2	18.7	20.2
Taxes accrued	24.7	28	26.1
Regulatory liabilities	6.9	3.9	2.4
Other	22.5	11.8	13.2
Total Current Liabilities	212.3	251.1	240.6
Deferred Credits and Other Liabilities:
Pension and postretirement benefit costs	73.8	74.9	58.7
Asset retirement obligations	378	374.3	150.2
Regulatory liabilities	18.4	18.5	22.3
Other	8.4	9.1	11.9
Total Deferred Credits and Other Liabilities	478.6	476.8	243.1
Commitments and Contingencies (Note 10)
Total Capitalization and Liabilities	$ 2,110.8	$ 2,051.4	$ 1,792.6

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
ASSETS
Non-utility property, accumulated depreciation and amortization	$ 22.2	$ 19	$ 13.9
Capitalization:
Common stock, par value (in dollars per share)	$ 1	$ 1	$ 1
Common stock, authorized (in shares)	70,000,000	70,000,000	70,000,000
Common stock, issued (in shares)	51,700,000	51,600,000	51,100,000
Common stock, outstanding (in shares)	51,700,000	51,600,000	51,100,000
Spire Missouri
Capitalization:
Common stock, par value (in dollars per share)	$ 1	$ 1	$ 1
Common stock, authorized (in shares)	50,000,000	50,000,000	50,000,000
Common stock, issued (in shares)	24,577	24,577	24,577
Common stock, outstanding (in shares)	24,577	24,577	24,577
Spire Alabama
Capitalization:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, authorized (in shares)	3,000,000	3,000,000	3,000,000
Common stock, issued (in shares)	2,000,000	2,000,000	2,000,000
Common stock, outstanding (in shares)	2,000,000	2,000,000	2,000,000
Depositary Shares, each representing a 1/1,000th interest in a share of 5.90% Series A Cumulative Redeemable Perpetual Preferred Stock, par value $25.00 per share
Capitalization:
Preferred stock, par value (in dollars per share)	$ 25	$ 25	$ 25
Preferred stock, depositary shares authorized (in shares)	10,000,000	10,000,000	10,000,000
Preferred stock, depositary shares outstanding (in shares)	10,000,000	10,000,000	10,000,000
Preferred stock, depositary shares issued (in shares)	10,000,000	10,000,000	10,000,000

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Millions	Total	Spire Missouri	Spire Alabama	Common Stock	Common StockSpire Missouri	Common StockSpire Alabama	Preferred Stock	Paid-in Capital	Paid-in CapitalSpire Missouri	Paid-in CapitalSpire Alabama	Retained Earnings	Retained EarningsSpire Missouri	Retained EarningsSpire Alabama	AOCI	[1]	AOCISpire Missouri	[1]
BALANCE at Sep. 30, 2019	$ 2,543	$ 1,339.3	$ 830	$ 51	$ 0.1		$ 242	$ 1,505.8	$ 765	$ 370.9	$ 775.5	$ 576.6	$ 459.1	$ (31.3)		$ (2.4)
BALANCE (in shares) at Sep. 30, 2019				50,973,515	24,577	1,972,052
Stockholders' Equity Rollforward
Net income	67	48	13.2								67	48	13.2
Dividend reinvestment plan	2.3							2.3
Dividend reinvestment plan (in shares)				28,764
Stock-based compensation costs	1.6							1.6
Stock issued under stock-based compensation plans				$ 0.1				(0.1)
Stock issued under stock-based compensation (in shares)				99,126
Employees’ tax withholding for stock-based compensation	(2.9)							(2.9)
Employee's tax withholding for stock-based compensation (in shares)				(37,945)
Temporary equity adjustment to redemption value	(0.1)										(0.1)
Dividends declared on common stock	(31.9)	(11.3)	(6)								(31.9)	(11.3)	(6)
Dividends declared on preferred stock	(7.4)										(7.4)
Other comprehensive income (loss), net of tax	14.4	0.1												14.4		0.1
BALANCE at Dec. 31, 2019	2,586	1,376.1	837.2	$ 51.1	$ 0.1		242	1,506.7	765	370.9	803.1	613.3	466.3	(16.9)		(2.3)
BALANCE (in shares) at Dec. 31, 2019				51,063,460	24,577	1,972,052
BALANCE at Sep. 30, 2020	2,522.3	1,435.1	851.7	$ 51.6	$ 0.1		242	1,549.2	765	350.9	720.7	672.9	500.8	(41.2)		(2.9)
BALANCE (in shares) at Sep. 30, 2020				51,611,789	24,577	1,972,052
Stockholders' Equity Rollforward
Net income	88.9	56.6	13.7								88.9	56.6	13.7
Dividend reinvestment plan	0.4							0.4
Dividend reinvestment plan (in shares)				6,698
Stock-based compensation costs	1.4							1.4
Stock issued under stock-based compensation plans				$ 0.1				(0.1)
Stock issued under stock-based compensation (in shares)				55,161
Employees’ tax withholding for stock-based compensation	(0.9)							(0.9)
Employee's tax withholding for stock-based compensation (in shares)				(14,175)
Temporary equity adjustment to redemption value	(0.9)										(0.9)
Return of capital to Spire			(11)							(11)
Dividends declared on common stock	(33.8)		(5.5)								(33.8)		(5.5)
Dividends declared on preferred stock	(3.7)										(3.7)
Other comprehensive income (loss), net of tax	13.1	0.1												13.1		0.1
BALANCE at Dec. 31, 2020	$ 2,586.8	$ 1,491.8	$ 848.9	$ 51.7	$ 0.1		$ 242	$ 1,550	$ 765	$ 339.9	$ 771.2	$ 729.5	$ 509	$ (28.1)		$ (2.8)
BALANCE (in shares) at Dec. 31, 2020				51,659,473	24,577	1,972,052
[1]	Accumulated other comprehensive income (loss)

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Statement Of Stockholders Equity [Abstract]
Dividends declared on common stock (in dollars per share)	$ 0.65	$ 0.6225
Dividends declared on preferred stock (in dollars per depositary share)	$ 0.36875	$ 0.7375

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating Activities:
Net Income	$ 88.9	$ 67
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	50.8	47.5
Deferred income taxes and investment tax credits	21.8	14.3
Changes in assets and liabilities:
Accounts receivable	(169.6)	(162.5)
Inventories	9.5	11.1
Regulatory assets and liabilities	11.2	45.6
Accounts payable	43.9	42.6
Delayed/advance customer billings, net	(5.8)	(3.5)
Taxes accrued	(30.2)	(24.9)
Other assets and liabilities	(15.4)	30.3
Other	2.5	(3)
Net cash provided by operating activities	7.6	64.5
Investing Activities:
Capital expenditures	(163.6)	(192.3)
Other	0	(0.3)
Net cash used in investing activities	(163.6)	(192.6)
Financing Activities:
Issuance of long-term debt	150	510
Repayment of long-term debt	(5.4)	(100)
Issuance (repayment) of short-term debt, net	48.1	(224.2)
Issuance of common stock	0.4	2.3
Dividends paid on common stock	(32.2)	(34.7)
Dividends paid on preferred stock	(3.7)	(3.7)
Other	(1.8)	(5.9)
Net cash provided by financing activities	155.4	143.8
Net (Decrease) Increase in Cash, Cash Equivalents, and Restricted Cash	(0.6)	15.7
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	4.1	5.8
Cash and Cash Equivalents at End of Period	3.5	21.5
Supplemental disclosure of cash (paid) received for:
Interest, net of amounts capitalized	(15.5)	(11.6)
Income taxes	0.1	0
Spire Missouri
Operating Activities:
Net Income	56.6	48
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	30.4	29
Deferred income taxes and investment tax credits	9.9	6.8
Changes in assets and liabilities:
Accounts receivable	(88.7)	(96.9)
Inventories	6.3	5.5
Regulatory assets and liabilities	7.2	32.8
Accounts payable	24.3	26.9
Delayed/advance customer billings, net	(5.6)	(2.4)
Taxes accrued	(25.7)	(21.7)
Other assets and liabilities	(8.6)	16.9
Other	0.2	0.2
Net cash provided by operating activities	6.3	45.1
Investing Activities:
Capital expenditures	(99.1)	(102.2)
Other	0.3	0
Net cash used in investing activities	(98.8)	(102.2)
Financing Activities:
Issuance of long-term debt	0	275
Repayment of long-term debt	0	(100)
Repayments to Spire, net	92.5	(98.3)
Dividends paid on common stock	0	(11.3)
Other	0	(1.6)
Net cash provided by financing activities	92.5	63.8
Net (Decrease) Increase in Cash, Cash Equivalents, and Restricted Cash	0	6.7
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	0	2.6
Cash and Cash Equivalents at End of Period	0	9.3
Supplemental disclosure of cash (paid) received for:
Interest, net of amounts capitalized	(9.6)	(7.5)
Income taxes	0	0
Spire Alabama
Operating Activities:
Net Income	13.7	13.2
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	15	14.3
Deferred income taxes and investment tax credits	4.8	4.5
Changes in assets and liabilities:
Accounts receivable	(37.8)	(34.3)
Inventories	(2.1)	4.2
Regulatory assets and liabilities	2.9	11.1
Accounts payable	10.4	(0.8)
Delayed/advance customer billings, net	(0.1)	(0.6)
Taxes accrued	(3.3)	(1.3)
Other assets and liabilities	(0.9)	0.6
Other	0.1	(2.7)
Net cash provided by operating activities	2.7	8.2
Investing Activities:
Capital expenditures	(40.9)	(38.7)
Other	0	(1.4)
Net cash used in investing activities	(40.9)	(40.1)
Financing Activities:
Issuance of long-term debt	150	100
Return of capital to Spire	(11)	0
Repayments to Spire, net	(94.4)	(61.6)
Dividends paid on common stock	(5.5)	(6)
Other	(0.9)	(0.5)
Net cash provided by financing activities	38.2	31.9
Net (Decrease) Increase in Cash, Cash Equivalents, and Restricted Cash	0	0
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	0	0
Cash and Cash Equivalents at End of Period	0	0
Supplemental disclosure of cash (paid) received for:
Interest, net of amounts capitalized	(3.6)	(2.9)
Income taxes	$ 0	$ 0

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES BASIS OF PRESENTATION – These notes are an integral part of the accompanying unaudited financial statements of Spire Inc. (“Spire” or the “Company”) presented on a consolidated basis, Spire Missouri Inc. (“Spire Missouri”) and Spire Alabama Inc. (“Spire Alabama”). Spire Missouri and Spire Alabama are wholly owned subsidiaries of Spire. Spire Missouri, Spire Alabama and the subsidiaries of Spire EnergySouth Inc. (“Spire EnergySouth”) are collectively referred to as the “Utilities.” The subsidiaries of Spire EnergySouth are Spire Gulf Inc. and Spire Mississippi Inc. 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-Q and Rule 10-01 of Regulation S‑X. Accordingly, they do not include all the disclosures required for complete financial statements. In the opinion of management, the accompanying unaudited financial statements include all adjustments necessary for the fair presentation of the results of operations for the periods presented. This Form 10-Q should be read in conjunction with the Notes to Financial Statements contained in Spire’s, Spire Missouri’s and Spire Alabama’s combined Annual Report on Form 10-K for the fiscal year ended September 30, 2020. 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 been eliminated from their separate financial statements. NATURE OF OPERATIONS – Spire has two reportable segments: Gas Utility and Gas Marketing. The Gas Utility segment consists of the regulated natural gas distribution operations of the Company and is the core business segment of Spire in terms of revenue and earnings. The Gas Utility segment is comprised of the operations of: Spire Missouri, serving St. Louis, Kansas City, and other areas in Missouri; Spire Alabama, serving central and northern Alabama; and the subsidiaries of Spire EnergySouth, serving southern Alabama and south-central Mississippi. The Gas Marketing segment includes Spire’s primary gas-related business, Spire Marketing Inc. (“Spire Marketing”), which provides non-regulated natural gas services, primarily in the central and southern United States (U.S.). The activities of other subsidiaries are reported as Other and are described in Note 9 , Information by Operating Segment. Spire Missouri and Spire Alabama each have a single reportable segment. Nearly all the Company’s earnings are derived from its Gas Utility segment. Due to the seasonal nature of the Utilities’ business and the Spire Missouri rate design, earnings are typically concentrated during the heating season of November through April each fiscal year. As a result, the interim statements of income for Spire, Spire Missouri and Spire Alabama are not necessarily indicative of annual results or representative of succeeding quarters of the fiscal year. DERIVATIVES – In the course of their business, certain subsidiaries of Spire enter into commitments associated with the purchase or sale of natural gas. Certain of their derivative natural gas contracts are designated as normal purchases or normal sales and, as such, are excluded from the scope of Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 815, Derivatives and Hedging . Those contracts are accounted for as executory contracts and recorded on an accrual basis. Revenues and expenses from such contracts are recorded gross. Contracts not designated as normal purchases or normal sales are recorded as derivatives with changes in fair value recognized in earnings in the periods prior to physical delivery. Certain of Spire Marketing’s wholesale purchase and sale transactions are classified as trading activities for financial reporting purposes. Under GAAP, revenues and expenses associated with trading activities are presented on a net basis in Gas Marketing operating revenues (or expenses, if negative) in the Condensed Consolidated Statements of Income. This net presentation has no effect on operating income or net income. REGULATED OPERATIONS – The Utilities account for their regulated operations in accordance with FASB ASC Topic 980, Regulated Operations . This topic sets forth the application of GAAP for those companies whose rates are established by or are subject to approval by an independent third-party regulator. The provisions of this accounting guidance require, among other things, that financial statements of a regulated enterprise reflect the actions of regulators, where appropriate. These actions may result in the recognition of revenues and expenses in time periods that are different than non-regulated enterprises. When this occurs, costs are deferred as assets in the balance sheet (regulatory assets) and recorded as expenses when those amounts are reflected in rates. In addition, regulators can impose liabilities upon a regulated company for amounts previously collected from customers and for recovery of costs that are expected to be incurred in the future (regulatory liabilities). Management believes that the current regulatory environment supports the continued use of these regulatory accounting principles and that all regulatory assets and regulatory liabilities are recoverable or refundable through the regulatory process. 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 4 , Regulatory Matters. TRANSACTIONS WITH AFFILIATES – Transactions between affiliates of the Company have been eliminated from the consolidated financial statements of Spire. Spire Missouri and Spire Alabama borrowed funds from the Company and incurred related interest, as reflected in their separate financial statements, and they participated in normal intercompany shared services transactions. In addition, Spire Missouri’s other transactions with affiliates are presented in the table below: Three Months Ended December 31, 2020 2019 Purchases of natural gas from Spire Marketing Inc. $ 10.7 $ 19.5 Transportation services received from Spire STL Pipeline LLC 8.1 3.9 Sales of natural gas to Spire Marketing Inc. 1.1 — Transportation services received from Spire NGL Inc. 0.3 0.3 In the three months ended December 31, 2020 and 2019, Spire Alabama had purchases of natural gas from Spire Marketing totaling $4.8 and $3.3, respectively. ACCRUED CAPITAL EXPENDITURES – Accrued capital expenditures, shown in the following table, are excluded from capital expenditures in the statements of cash flows until paid. December 31, September 30, December 31, 2020 2020 2019 Spire $ 40.9 $ 67.6 $ 45.8 Spire Missouri 23.1 34.3 20.2 Spire Alabama 4.2 17.0 9.8 ACCOUNTS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES – Trade accounts receivable are recorded at the amounts due from customers, including unbilled amounts. Accounts receivable are written off when they are deemed to be uncollectible. An allowance for expected credit losses is estimated and updated based on relevant data and trends such as accounts receivable aging, historical write-off experience, current write-off trends, economic conditions, and the impact of weather and availability of customer payment assistance on collection trends. For the Utilities, net write-offs as a percentage of revenue has historically been the best predictor of base net write-off experience over time. Management judgment is applied in the development of the allowance due to the complexity of variables and subjective nature of certain relevant factors. For December 31, 2020, and September 30, 2020, the estimates for expected credit losses were increased as a result of considerations related to the outbreak of the novel coronavirus (COVID-19), including trends from previous economic downturns, the effects of moratoriums on cutoffs, and the effects of slower-than-normal disconnection activity in general, offset by the amount subject to specific recovery under Missouri’s deferral order (see Note 4 , Regulatory Matters). The accounts receivable of Spire’s non-utility businesses are evaluated separately from those of the Utilities. The allowance for credit losses for those other businesses is based on a continuous evaluation of the individual counterparty risk and is not significant for the periods presented. Activity in the allowance for credit losses for the three months ended December 31, 2020, is shown in the following table. Spire Spire Spire Missouri Alabama Allowance at beginning of period $ 24.9 $ 18.1 $ 5.5 Provision for expected credit losses 4.1 3.3 0.7 Write-offs, net of recoveries (0.1 ) — — Allowance at end of period $ 28.9 $ 21.4 $ 6.2 NEW ACCOUNTING PRONOUNCEMENTS – In June 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments , which was later supplemented by ASU Nos. 2018-19, 2019-04, 2019-05 and 2019-11. The new standard replaces the current “incurred loss” model with an “expected loss” model for certain instruments, including trade receivables, requiring measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. It also required entities to record credit loss allowances for available-for-sale securities rather than impair the carrying amount of the securities. Spire, Spire Missouri and Spire Alabama adopted the new standard for the quarter ended December 31, 2020. Based on the credit quality of the existing available-for-sale securities portfolio, no allowance for credit losses was recognized for those investments. Application of the new guidance did not result in any significant modifications to the Company’s policies related to recognizing an allowance on trade receivables, and the adoption of the new standard did not have a material impact on Spire’s, Spire Missouri’s and Spire Alabama’s financial statements. RECLASSIFICATIONS – Spire’s consolidated statements of income historically showed Gas Utility operating revenues and expense line items separately from Gas Marketing and other operations. The current presentation shows operating revenues and expense line items on a consolidated basis. Disaggregated data is presented in Note 9 , Information by Operating Segment. Prior period amounts have been reclassified to conform with the current period presentation.

Revenue

Revenue	3 Months Ended
	Dec. 31, 2020
Revenue From Contract With Customer [Abstract]
Revenue	2. REVENUE The following tables show revenue disaggregated by source and customer type. Three Months Ended December 31, 2020 2019 Spire Gas Utility: Residential $ 349.9 $ 368.4 Commercial & industrial 103.0 122.5 Transportation 32.2 31.0 Off-system & other incentive 9.3 9.4 Other customer revenue 2.2 2.4 Total revenue from contracts with customers 496.6 533.7 Changes in accrued revenue under alternative revenue programs 1.6 (3.0 ) Total Gas Utility operating revenues 498.2 530.7 Gas Marketing: Revenue from contracts with retail customers 19.4 32.3 Revenue from wholesale derivative contracts 5.4 — Total Gas Marketing operating revenues 24.8 32.3 Other 16.7 11.1 Total before eliminations 539.7 574.1 Intersegment eliminations (see Note 9, Information by Operating Segment) (27.1 ) (7.2 ) Total Operating Revenues $ 512.6 $ 566.9 Spire Missouri Residential $ 263.0 $ 275.9 Commercial & industrial 69.9 80.8 Transportation 9.0 9.0 Off-system & other incentive 7.4 9.4 Other customer revenue 2.9 0.5 Total revenue from contracts with customers 352.2 375.6 Changes in accrued revenue under alternative revenue programs 3.3 (1.6 ) Total Operating Revenues $ 355.5 $ 374.0 Spire Alabama Residential $ 69.2 $ 74.3 Commercial & industrial 24.3 31.3 Transportation 20.5 19.6 Off-system & other incentive 2.0 — Other customer revenue (1.9 ) 1.6 Total revenue from contracts with customers 114.1 126.8 Changes in accrued revenue under alternative revenue programs (0.5 ) (0.6 ) Total Operating Revenues $ 113.6 $ 126.2 For the three months ended December 31, 2020, Spire Alabama recorded a negative adjustment of $3.4 (included in “other customer revenue”) under its Rate Stabilization and Equalization (RSE) rate-setting process based on the quarter-end estimate of its average common equity at the end of the rate year relative to its allowed range of return. Gross receipts taxes associated with the Company’s natural gas utility services are imposed on the Company, Spire Missouri, and Spire Alabama and billed to its customers. The expense amounts (shown in the table below) are reported gross in the “Taxes, other than income taxes” line in the statements of income, and corresponding revenues are reported in “Operating Revenues.” Three Months Ended December 31, 2020 2019 Spire $ 21.7 $ 24.6 Spire Missouri 15.2 17.2 Spire Alabama 5.3 6.2

Earnings Per Common Share

Earnings Per Common Share	3 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings Per Common Share	3. EARNINGS PER COMMON SHARE Three Months Ended December 31, 2020 2019 Basic Earnings Per Common Share: Net Income $ 88.9 $ 67.0 Less: Provision for preferred dividends 3.7 3.7 Income allocated to participating securities 0.1 0.1 Income Available to Common Shareholders $ 85.1 $ 63.2 Weighted Average Common Shares Outstanding (in millions) 51.5 50.9 Basic Earnings Per Common Share $ 1.65 $ 1.24 Diluted Earnings Per Common Share: Net Income $ 88.9 $ 67.0 Less: Provision for preferred dividends 3.7 3.7 Income allocated to participating securities 0.1 0.1 Income Available to Common Shareholders $ 85.1 $ 63.2 Weighted Average Common Shares Outstanding (in millions) 51.5 50.9 Dilutive Effect of Restricted Stock and Restricted Stock Units (in millions)* 0.1 0.2 Weighted Average Diluted Common Shares (in millions) 51.6 51.1 Diluted Earnings Per Common Share $ 1.65 $ 1.24 * Calculation excludes certain outstanding common shares (shown in millions by period at the right) attributable to stock units subject to performance or market conditions and restricted stock, which could have a dilutive effect in the future 0.2 0.1

Regulatory Matters

Regulatory Matters	3 Months Ended
	Dec. 31, 2020
Regulated Operations [Abstract]
Regulatory Matters	4. REGULATORY MATTERS As explained in Note 1 , Summary of Significant Accounting Policies, the Utilities account for regulated operations in accordance with FASB ASC Topic 980, Regulated Operations December 31, September 30, December 31, Spire 2020 2020 2019 Regulatory Assets: Current: Pension and postretirement benefit costs $ 30.6 $ 30.6 $ 30.1 Unamortized purchased gas adjustments 8.4 5.5 9.1 Other 31.5 33.4 28.7 Total Current Regulatory Assets 70.5 69.5 67.9 Noncurrent: Pension and postretirement benefit costs 428.6 439.3 405.5 Cost of removal 417.4 395.6 152.1 Future income taxes due from customers 125.4 123.5 111.6 Energy efficiency 41.4 39.6 37.2 Unamortized purchased gas adjustments 3.8 12.1 — Other 62.6 59.3 44.1 Total Noncurrent Regulatory Assets 1,079.2 1,069.4 750.5 Total Regulatory Assets $ 1,149.7 $ 1,138.9 $ 818.4 Regulatory Liabilities: Current: Pension and postretirement benefit costs $ 5.8 $ 5.8 $ 5.8 Unamortized purchased gas adjustments 54.8 73.1 19.9 Other 34.9 34.1 24.3 Total Current Regulatory Liabilities 95.5 113.0 50.0 Noncurrent: Deferred taxes due to customers 136.0 138.8 177.0 Pension and postretirement benefit costs 163.7 157.6 147.5 Accrued cost of removal 28.6 28.6 38.7 Unamortized purchased gas adjustments 14.8 4.4 24.3 Other 14.2 14.3 30.3 Total Noncurrent Regulatory Liabilities 357.3 343.7 417.8 Total Regulatory Liabilities $ 452.8 $ 456.7 $ 467.8 December 31, September 30, December 31, Spire Missouri 2020 2020 2019 Regulatory Assets: Current: Pension and postretirement benefit costs $ 21.9 $ 21.9 $ 21.9 Other 10.2 10.2 7.5 Total Current Regulatory Assets 32.1 32.1 29.4 Noncurrent: Future income taxes due from customers 116.6 114.6 104.9 Pension and postretirement benefit costs 324.6 332.6 324.7 Energy efficiency 41.4 39.6 37.2 Unamortized purchased gas adjustments 3.8 12.1 — Cost of removal 18.3 7.1 — Other 45.7 42.7 24.3 Total Noncurrent Regulatory Assets 550.4 548.7 491.1 Total Regulatory Assets $ 582.5 $ 580.8 $ 520.5 Regulatory Liabilities: Current: Pension and postretirement benefit costs $ 3.6 $ 3.6 $ 3.6 Unamortized purchased gas adjustments 54.3 72.3 19.0 Other 25.5 27.3 19.8 Total Current Regulatory Liabilities 83.4 103.2 42.4 Noncurrent: Deferred taxes due to customers 118.6 121.4 159.7 Pension and postretirement benefit costs 146.1 140.4 124.9 Accrued cost of removal — — 12.1 Unamortized purchased gas adjustments 14.8 4.4 24.3 Other 8.7 8.6 24.5 Total Noncurrent Regulatory Liabilities 288.2 274.8 345.5 Total Regulatory Liabilities $ 371.6 $ 378.0 $ 387.9 December 31, September 30, December 31, Spire Alabama 2020 2020 2019 Regulatory Assets: Current: Pension and postretirement benefit costs $ 7.7 $ 7.7 $ 7.2 Unamortized purchased gas adjustments 8.3 5.5 8.8 Other 6.7 7.2 8.4 Total Current Regulatory Assets 22.7 20.4 24.4 Noncurrent: Pension and postretirement benefit costs 95.7 98.2 74.9 Cost of removal 399.1 388.6 152.1 Future income taxes due from customers 2.2 2.2 — Other 1.2 0.9 3.2 Total Noncurrent Regulatory Assets 498.2 489.9 230.2 Total Regulatory Assets $ 520.9 $ 510.3 $ 254.6 Regulatory Liabilities: Current: Pension and postretirement benefit costs $ 2.2 $ 2.2 $ 2.2 Other 4.7 1.7 0.2 Total Current Regulatory Liabilities 6.9 3.9 2.4 Noncurrent: Pension and postretirement benefit costs 14.7 14.8 18.4 Other 3.7 3.7 3.9 Total Noncurrent Regulatory Liabilities 18.4 18.5 22.3 Total Regulatory Liabilities $ 25.3 $ 22.4 $ 24.7 A portion of the Company’s and Spire Missouri’s regulatory assets are not earning a return, as shown in the table below: December 31, September 30, December 31, 2020 2020 2019 Spire Pension and postretirement benefit costs $ 229.7 $ 232.3 $ 208.0 Future income taxes due from customers 123.2 121.3 111.6 Other 12.4 12.9 14.1 Total Regulatory Assets Not Earning a Return $ 365.3 $ 366.5 $ 333.7 Spire Missouri Pension and postretirement benefit costs $ 229.7 $ 232.3 $ 208.0 Future income taxes due from customers 116.6 114.6 104.9 Other 12.4 12.9 14.1 Total Regulatory Assets Not Earning a Return $ 358.7 $ 359.8 $ 327.0 Like all the Company’s regulatory assets, these regulatory assets are expected to be recovered from customers in future rates. The recovery period for the future income taxes due from customers and pension and other postretirement benefit costs could be 20 years or longer, based on current Internal Revenue Service guidelines and average remaining service life of active participants, respectively. The other items not earning a return are expected to be recovered over a period not to exceed 15 years, consistent with precedent set by the MoPSC. Spire Alabama does not have any regulatory assets that are not earning a return. On March 7, 2018, the MoPSC issued its order in two general rate cases (docketed as GR-2017-0215 and GR-2017-0216), approving new tariffs that became effective on April 19, 2018. Certain provisions of the order allow less future recovery of certain deferred or capitalized costs than estimated based upon previous rate proceedings, and management determined that the related regulatory assets should be written down or off in connection with the preparation of the financial statements for the second quarter of 2018. Spire Missouri filed an appeal of the MoPSC’s order related to the disallowance of certain pension costs incurred prior to 1997 ($28.8), real estate sold in 2014 ($1.8), and rate case expenses ($0.9) to Missouri’s Southern District Court of Appeals. On March 15, 2019, the appeal was denied by that court, and Spire Missouri requested review by the Missouri Supreme Court. Oral arguments were made before the Missouri Supreme Court on January 29, 2020. The case is awaiting a decision. In the first quarter of fiscal 2020, a provision of $2.1 was recorded to Spire Missouri’s regulatory liability for Infrastructure System Replacement Surcharge (ISRS) revenues related to customer billings recorded during the quarter under a disputed ISRS filing, along with a $0.5 provision for interest due on all ISRS revenues in dispute. The after-tax impact of the first quarter provisions reduced net income by $2.0, which is excluded for the net economic earnings financial measure. As previously disclosed, these matters were settled by the end of fiscal 2020. In September 2020, Spire Missouri, the MoPSC staff and the OPC reached a Unanimous Stipulation and Agreement regarding Spire Missouri’s request for an Accounting Authority Order (AAO) pertaining to certain costs and lost customer fee revenue related to the COVID-19 pandemic. In October 2020, the MoPSC issued an order approving that agreement and granting an AAO. Accordingly, Spire Missouri recorded a regulatory asset of $3.9 and $3.8 as of December 31 and September 30, 2020, respectively, related to the deferral of applicable costs and is tracking lost customer fee revenue. All ratemaking treatment of the deferrals and any revenue recoveries is reserved for consideration in Spire Missouri’s next general rate case. On December 11, 2020, Spire Missouri filed a general rate case with the MoPSC that includes new proposed rates for its service areas. The case proposes an increase in base rates, reflecting recovery of system investments and operating costs necessary to maintain the safety and reliability of its natural gas distribution systems as well as to support enhancements to customer service. The request, if approved, represents a net base rate increase of $64.2. Spire Missouri is already recovering $47.3 from customers through the ISRS, resulting in a total base rate increase request of $111.5. The ISRS cap would then be reset in order to continue the timely recovery of the investment in pipeline upgrades. The proposed rates are calculated on a filed rate base of $2,780 based on the end of fiscal year 2020, reflecting the significant investment made in infrastructure upgrades and other systems. Among other things, the filing changes rate design, proposes new customer programs, and aligns the tariffs of the company’s service areas. The filing assumes a common equity ratio of 54.25% and a 9.95% return on equity. Management anticipates that certain measures, such as rate base, capital structure and operating costs will be updated over the course of the rate proceeding. In accordance with Missouri law, the MoPSC has up to 11 months to consider this filing. In August 2018, the Federal Energy Regulatory Commission (FERC) approved an order issuing a Certificate of Public Convenience and Necessity for the Spire STL Pipeline (“August 2018 Order”), and in November 2018, the FERC issued a Notice to Proceed, allowing construction to begin. In November 2019, Spire STL Pipeline received FERC authorization to place the STL Pipeline into service. Also, in November 2019, the FERC issued an Order on Rehearing of the August 2018 Order dismissing or denying the outstanding requests for rehearing filed by several parties, dismissing the request for stay filed by one party, and noting the withdrawal of the request for rehearing by another party. On January 21, 2020, two of the rehearing parties filed petitions for review of the FERC’s orders with the U.S. Court of Appeals for the District of Columbia Circuit. Spire STL Pipeline and Spire Missouri have intervened and filed responsive briefs in this proceeding, which remains pending. On October 9, 2020, Spire Storage filed with the FERC an Abbreviated Application for an Amendment of Certificate of Public Convenience and Necessity, Reaffirmation of Market-Based Rate Authority, and Related Authorizations pursuant to Section 7(c) of the Natural Gas Act. The application requests authorization to expand capacity and increase pipeline connectivity at certain of Spire Storage’s natural gas storage facilities in Wyoming.

Financing Arrangements and Long

Financing Arrangements and Long-term Debt	3 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Financing Arrangements and Long-term Debt	5. FINANCING ARRANGEMENTS AND LONG-TERM DEBT Spire, Spire Missouri and Spire Alabama have a syndicated revolving credit facility pursuant to a loan agreement with 11 banks, expiring October 31, 2023. The loan agreement has an aggregate credit commitment of $975.0, including sublimits of $300.0 for Spire, $475.0 for Spire Missouri, and $200.0 for Spire Alabama. These sublimits may be reallocated from time to time among the three borrowers within the $975.0 aggregate commitment, with commitments fees applied for each borrower relative to its credit rating. Spire may use its line to provide for the funding needs of various subsidiaries. The agreement also contains financial covenants limiting each borrower’s consolidated total debt, including short-term debt, to no more than 70% of its total capitalization. As defined in the line of credit, on December 31, 2020, total debt was less than 60% of total capitalization for each borrower. Spire has a commercial paper program (“CP Program”) pursuant to which Spire may issue short-term, unsecured commercial paper notes. Amounts available under the CP Program may be borrowed, repaid and re-borrowed from time to time, with the aggregate face or principal amount of the notes outstanding under the CP Program at any time not to exceed $975.0. The notes may have maturities of up to 365 days from date of issue. On March 26, 2020, Spire entered into a new loan agreement with two banks providing for a term loan of $150.0, which was immediately fully funded. It was repaid on December 16, 2020. The term loan bore interest at the LIBOR Rate (as defined in the loan agreement) plus 0.85% per annum. Proceeds were used for working capital and general corporate purposes. Information about Spire’s consolidated short-term borrowings and about Spire Missouri’s and Spire Alabama’s borrowings from Spire is presented in the following table. As of December 31, 2020, $455.5 of Spire’s short-term borrowings were used to support lending to the Utilities. Spire (Parent Only) Spire Missouri Spire Alabama Spire Credit Term CP Credit Spire Credit Spire Consol- Facility Loan Program Facility Note Facility Note idated Three Months Ended December 31, 2020 Weighted average borrowings $ — $ 125.5 $ 609.2 $ — $ 341.3 $ — $ 111.6 $ 734.7 Lowest borrowings outstanding — — 497.0 — 292.8 — 1.5 631.1 Highest borrowings outstanding — 150.0 701.1 — 396.7 — 152.2 850.5 Weighted average interest rate n/a 1.1 % 0.2 % n/a 0.2 % n/a 0.2 % 0.4 % As of December 31, 2020 Borrowings outstanding $ — $ — $ 696.1 $ — $ 393.7 $ — $ 27.0 $ 696.1 Weighted average interest rate n/a n/a 0.3 % n/a 0.3 % n/a 0.3 % 0.3 % As of September 30, 2020 Borrowings outstanding $ — $ 150.0 $ 498.0 $ — $ 301.2 $ — $ 121.3 $ 648.0 Weighted average interest rate n/a 1.1 % 0.2 % n/a 0.2 % n/a 0.2 % 0.6 % As of December 31, 2019 Borrowings outstanding $ — $ — $ 518.9 $ — $ 288.1 $ — $ 67.1 $ 518.9 Weighted average interest rate n/a n/a 2.1 % n/a 2.1 % n/a 2.1 % 2.1 % The long-term debt agreements of Spire, Spire Missouri and Spire Alabama contain customary covenants and default provisions. As of December 31, 2020, there were no events of default under these covenants. Interest expense shown on Spire’s consolidated statements of income and Spire Missouri’s statements of comprehensive income is net of the capitalized interest amounts shown in the following table. Three Months Ended December 31, 2020 2019 Spire $ 0.9 $ 2.2 Spire Missouri — 0.3 Spire Alabama 0.6 0.6 On December 15, 2020, Spire Alabama issued and sold to certain institutional investors in a private placement $150.0 of 2.04% Series 2020 Senior Notes due December 15, 2030. Interest is payable semi-annually. The notes are senior unsecured obligations of Spire Alabama and rank equal in right to payment with all its other senior unsecured indebtedness. Spire Alabama used the proceeds to repay short-term debt.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	6. FAIR VALUE OF FINANCIAL INSTRUMENTS The carrying amounts of cash and cash equivalents 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 7 , Fair Value Measurements, for information on financial instruments measured at fair value on a recurring basis. The carrying amounts and estimated fair values of financial instruments not measured at fair value on a recurring basis are shown in the following tables, classified according to the fair value hierarchy. There were no such instruments classified as Level 3 (significant unobservable inputs) as of December 31, 2020, September 30, 2020, and December 31, 2019. Classification of Estimated Fair Value Carrying Amount Fair Value Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Spire As of December 31, 2020 Cash and cash equivalents $ 3.5 $ 3.5 $ 3.5 $ — Notes payable 696.1 696.1 — 696.1 Long-term debt, including current portion 2,628.4 3,119.5 — 3,119.5 As of September 30, 2020 Cash and cash equivalents $ 4.1 $ 4.1 $ 4.1 $ — Notes payable 648.0 648.0 — 648.0 Long-term debt, including current portion 2,484.1 2,908.6 — 2,908.6 As of December 31, 2019 Cash and cash equivalents $ 21.5 $ 21.5 $ 21.5 $ — Notes payable 518.9 518.9 — 518.9 Long-term debt, including current portion 2,529.7 2,765.9 — 2,765.9 Spire Missouri As of December 31, 2020 Notes payable – associated companies $ 393.7 $ 393.7 $ — $ 393.7 Long-term debt 1,092.2 1,329.0 — 1,329.0 As of September 30, 2020 Notes payable – $ 301.2 $ 301.2 $ — $ 301.2 Long-term debt 1,092.0 1,313.5 — 1,313.5 As of December 31, 2019 Cash and cash equivalents $ 9.3 $ 9.3 $ 9.3 $ — Notes payable – 288.1 288.1 — 288.1 Long-term debt 1,098.6 1,234.9 — 1,234.9 Spire Alabama As of December 31, 2020 Notes payable – $ 27.0 $ 27.0 $ — $ 27.0 Long-term debt, including current portion 621.0 742.9 — 742.9 As of September 30, 2020 Notes payable – $ 121.3 $ 121.3 $ — $ 121.3 Long-term debt 471.8 576.9 — 576.9 As of December 31, 2019 Notes payable – $ 67.1 $ 67.1 $ — $ 67.1 Long-term debt, including current portion 511.7 572.8 — 572.8

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	7. FAIR VALUE MEASUREMENTS The information presented below categorizes the assets and liabilities in the balance sheets that are accounted for at fair value on a recurring basis in periods subsequent to initial recognition. The mutual funds included in Level 1 are valued based on exchange-quoted market prices of individual securities. Derivative instruments included in Level 1 are valued using quoted market prices on the New York Mercantile Exchange (NYMEX) or the Intercontinental Exchange (ICE). Derivative instruments classified in Level 2 include physical commodity derivatives that are valued using broker or dealer quotation services whose prices are derived principally from, or are corroborated by, observable market inputs. Also included in Level 2 are certain derivative instruments that have values that are similar to, and correlate with, quoted prices for exchange-traded instruments in active markets. Derivative instruments included in Level 3 are valued using generally unobservable inputs that are based upon the best information available and reflect management’s assumptions about how market participants would price the asset or liability. There were no material Level 3 balances as of December 31, 2020, and those Level 3 balances at September 30, 2020, and December 31, 2019, consisted of gas commodity contracts. The Company’s and the Utilities’ policy is to recognize transfers between the levels of the fair value hierarchy, if any, as of the beginning of the interim reporting period in which circumstances change or events occur to cause the transfer. The mutual funds are included in “Other Investments” on the Company’s balance sheets and in “Other Property and Investments” on Spire Missouri’s balance sheets. Derivative assets and liabilities, including receivables and payables associated with cash margin requirements, are presented net in the balance sheets when a legally enforceable netting agreement exists between the Company, Spire Missouri, or Spire Alabama and the counterparty to a derivative contract. Spire Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Effects of Netting and Cash Margin Receivables /Payables Total As of December 31, 2020 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 23.4 $ — $ — $ — $ 23.4 Gasoline and heating oil contracts 0.4 — — (0.4 ) — Gas Marketing: NYMEX/ICE natural gas contracts 0.3 21.5 — (12.4 ) 9.4 Natural gas commodity contracts — 14.9 — — 14.9 Other: U.S. stock/bond mutual funds 14.2 — — — 14.2 Interest rate swaps — 7.0 — — 7.0 Total $ 38.3 $ 43.4 $ — $ (12.8 ) $ 68.9 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 4.9 $ — $ — $ (4.9 ) $ — Gas Marketing: NYMEX/ICE natural gas contracts — 9.2 — (9.2 ) — Natural gas commodity contracts — 12.2 — — 12.2 Other: Interest rate swaps — 44.0 — — 44.0 Total $ 4.9 $ 65.4 $ — $ (14.1 ) $ 56.2 Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Effects of Netting and Cash Margin Receivables /Payables Total As of September 30, 2020 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 21.9 $ — $ — $ — $ 21.9 NYMEX/ICE natural gas contracts 6.3 — — (6.3 ) — Gasoline and heating oil contracts 0.3 — — (0.3 ) — Gas Marketing: NYMEX/ICE natural gas contracts — 27.7 — (25.4 ) 2.3 Natural gas commodity contracts — 14.5 0.4 — 14.9 Other: U.S. stock/bond mutual funds 18.6 — — — 18.6 Total $ 47.1 $ 42.2 $ 0.4 $ (32.0 ) $ 57.7 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 0.9 $ — $ — $ (0.9 ) $ — Gas Marketing: NYMEX/ICE natural gas contracts 0.7 21.4 — (22.1 ) — Natural gas commodity contracts — 22.3 — — 22.3 Other: Interest rate swaps — 54.2 — — 54.2 Total $ 1.6 $ 97.9 $ — $ (23.0 ) $ 76.5 As of December 31, 2019 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 21.2 $ — $ — $ — $ 21.2 Gas Marketing: NYMEX/ICE natural gas contracts 0.6 4.9 — (5.3 ) 0.2 Natural gas commodity contracts — 20.6 — (4.4 ) 16.2 Other: U.S. stock/bond mutual funds 16.6 — — — 16.6 Total $ 38.4 $ 25.5 $ — $ (9.7 ) $ 54.2 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 16.0 $ — $ — $ (16.0 ) $ — Gas Marketing: NYMEX/ICE natural gas contracts 0.4 8.0 — (8.4 ) — Natural gas commodity contracts — 19.5 1.5 (4.4 ) 16.6 Other: Interest rate swaps — 24.5 — — 24.5 Total $ 16.4 $ 52.0 $ 1.5 $ (28.8 ) $ 41.1 Spire Missouri Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Effects of Netting and Cash Margin Receivables /Payables Total As of December 31, 2020 ASSETS U.S. stock/bond mutual funds $ 23.4 $ — $ — $ — $ 23.4 Gasoline and heating oil contracts 0.4 — — (0.4 ) — Total $ 23.8 $ — $ — $ (0.4 ) $ 23.4 LIABILITIES NYMEX/ICE natural gas contracts $ 4.9 $ — $ — $ (4.9 ) $ — As of September 30, 2020 ASSETS U.S. stock/bond mutual funds $ 21.9 $ — $ — $ — $ 21.9 NYMEX/ICE natural gas contracts 6.3 — — (6.3 ) — Gasoline and heating oil contracts 0.3 — — (0.3 ) — Total $ 28.5 $ — $ — $ (6.6 ) $ 21.9 LIABILITIES NYMEX/ICE natural gas contracts $ 0.9 $ — $ — $ (0.9 ) $ — As of December 31, 2019 ASSETS U.S. stock/bond mutual funds $ 21.2 $ — $ — $ — $ 21.2 LIABILITIES NYMEX/ICE natural gas contracts $ 16.0 $ — $ — $ (16.0 ) $ —

Pension Plans and Other Postret

Pension Plans and Other Postretirement Benefits	3 Months Ended
	Dec. 31, 2020
Compensation And Retirement Disclosure [Abstract]
Pension Plans and Other Postretirement Benefits	8. PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS Pension Plans Spire and the Utilities maintain pension plans for their employees. Spire Missouri has non-contributory, defined benefit, trusteed forms of pension plans covering the majority of its employees. Plan assets consist primarily of corporate and U.S. government obligations and a growth segment consisting of exposure to equity markets, commodities, real estate and inflation-indexed securities, achieved through derivative instruments. Spire Alabama has non-contributory, defined benefit, trusteed forms of pension plans covering the majority of its 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 included the following components: Three Months Ended December 31, 2020 2019 Spire Service cost – benefits earned during the period $ 5.6 $ 5.5 Interest cost on projected benefit obligation* 5.2 5.9 Expected return on plan assets* (8.0 ) (9.2 ) Amortization of prior service credit* (0.8 ) (0.6 ) Amortization of actuarial loss* 4.0 3.7 Subtotal 6.0 5.3 Regulatory adjustment 9.6 9.6 Net pension cost $ 15.6 $ 14.9 Spire Missouri Service cost – benefits earned during the period $ 3.9 $ 3.8 Interest cost on projected benefit obligation* 3.5 4.2 Expected return on plan assets* (5.6 ) (6.6 ) Amortization of prior service credit* (0.2 ) — Amortization of actuarial loss* 2.9 2.9 Subtotal 4.5 4.3 Regulatory adjustment 7.6 7.7 Net pension cost $ 12.1 $ 12.0 Spire Alabama Service cost – benefits earned during the period $ 1.5 $ 1.5 Interest cost on projected benefit obligation* 1.2 1.2 Expected return on plan assets* (1.6 ) (1.7 ) Amortization of prior service credit* (0.6 ) (0.6 ) Amortization of actuarial loss* 1.1 0.8 Subtotal 1.6 1.2 Regulatory adjustment 1.8 1.7 Net pension cost $ 3.4 $ 2.9 * Denotes pension expense line items that are recorded below the operating income line in the income statements, in the line item “Other Income, Net.” Pursuant to the provisions of Spire Missouri’s and Spire Alabama’s pension plans, pension obligations may be satisfied by monthly annuities, lump-sum cash payments, or special termination benefits. Lump-sum payments are recognized as settlements (which can result in gains or losses) only if the total of such payments exceeds the sum of service and interest costs in a specific year. Special termination benefits, when offered, are also recognized as settlements which can result in plans met the criteria for settlement recognition. The funding policy of the Utilities is to contribute an amount not less than the minimum required by government funding standards, nor more than the maximum deductible amount for federal income tax purposes. Fiscal 2021 contributions to Spire Missouri’s pension plans through December 31, 2020 were $20.2 to the qualified trusts and none to non-qualified plans. There were $2.2 of fiscal 2021 contributions to the Spire Alabama pension plans through December 31, 2020. Contributions to the qualified trusts of Spire Missouri’s pension plans for the remainder of fiscal 2021 are anticipated to be $21.8. Contributions to Spire Alabama’s pension plans for the remainder of fiscal 2021 are anticipated to be $8.9. 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. For retirements prior to January 1, 2015, certain Spire Missouri plans provided medical insurance after retirement until death. The Spire Alabama plans provide medical insurance upon retirement until death for certain retirees depending on the type of employee and the date the employee was originally hired. Net periodic postretirement benefit costs consisted of the following components: Three Months Ended December 31, 2020 2019 Spire Service cost – benefits earned during the period $ 1.8 $ 1.4 Interest cost on accumulated postretirement benefit obligation* 1.4 1.6 Expected return on plan assets* (4.0 ) (4.1 ) Amortization of prior service cost (credit)* 0.3 (0.2 ) Amortization of actuarial gain* (0.4 ) (0.5 ) Subtotal (0.9 ) (1.8 ) Regulatory adjustment 3.4 4.0 Net postretirement benefit cost $ 2.5 $ 2.2 Spire Missouri Service cost – benefits earned during the period $ 1.6 $ 1.3 Interest cost on accumulated postretirement benefit obligation* 1.1 1.2 Expected return on plan assets* (2.7 ) (2.8 ) Amortization of prior service cost (credit) * 0.2 (0.1 ) Amortization of actuarial gain* (0.4 ) (0.5 ) Subtotal (0.2 ) (0.9 ) Regulatory adjustment 3.8 4.4 Net postretirement benefit cost $ 3.6 $ 3.5 Spire Alabama Service cost – benefits earned during the period $ 0.2 $ 0.1 Interest cost on accumulated postretirement benefit obligation* 0.3 0.3 Expected return on plan assets* (1.2 ) (1.2 ) Amortization of prior service cost (credit)* 0.1 (0.1 ) Subtotal (0.6 ) (0.9 ) Regulatory adjustment (0.4 ) (0.4 ) Net postretirement benefit income $ (1.0 ) $ (1.3 ) * Denotes other postretirement expense line items that are recorded below the operating income line in the income statements, in the line item “Other Income, Net.” 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. 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

Information by Operating Segmen

Information by Operating Segment	3 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Information by Operating Segment	9. INFORMATION BY OPERATING SEGMENT The Company has two reportable segments: Gas Utility and Gas Marketing. The Gas Utility segment is the aggregation of the operations of the Utilities. The Gas Marketing segment includes the results of Spire Marketing, a subsidiary engaged in the non-regulated marketing of natural gas and related activities, including utilizing natural gas storage contracts for providing natural gas sales. Other components of the Company’s consolidated information include: • unallocated corporate items, including certain debt and associated interest costs; • Spire STL Pipeline, a subsidiary of Spire which has constructed and, as of November 2019, operates a 65-mile FERC-regulated pipeline to deliver natural gas into eastern Missouri; • Spire Storage, a subsidiary of Spire providing physical natural gas storage services; and • Spire’s subsidiaries engaged in the operation of a propane pipeline, the compression of natural gas, and risk management, among other activities. Accounting policies are described in Note 1 , Summary of Significant Accounting Policies. Intersegment transactions include sales of natural gas from Spire Marketing to Spire Missouri, Spire Alabama and Spire Storage, sales of natural gas from Spire Missouri and Spire Alabama to Spire Marketing, propane transportation services provided by Spire NGL Inc. to Spire Missouri, and propane storage services provided by Spire Missouri to Spire NGL Inc. 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 (discussed in Note 1 ) and other non-recurring or unusual items such as certain regulatory, legislative, or GAAP standard-setting actions. For the fiscal 2020 periods presented, adjustments for Spire Missouri ISRS revenues reflect the regulatory settlement reached in the third quarter of fiscal 2020, as discussed in Note 4 , Regulatory Matters, such that the related GAAP provision for customer credit for fiscal 2020 to date is reflected in net economic earnings. Gas Utility Gas Marketing Other Eliminations Consolidated Three Months Ended December 31, 2020 Operating Revenues: Revenues from external customers $ 497.2 $ 10.7 $ 4.7 $ — $ 512.6 Intersegment revenues 1.0 14.1 12.0 (27.1 ) — Total Operating Revenues 498.2 24.8 16.7 (27.1 ) 512.6 Operating Expenses: Natural gas 204.3 0.7 — (23.8 ) 181.2 Operation and maintenance 103.0 3.3 8.6 (3.3 ) 111.6 Depreciation and amortization 48.6 0.3 1.9 — 50.8 Taxes, other than income taxes 35.5 0.2 0.4 — 36.1 Total Operating Expenses 391.4 4.5 10.9 (27.1 ) 379.7 Operating Income $ 106.8 $ 20.3 $ 5.8 $ — $ 132.9 Net Economic Earnings (Loss) $ 76.4 $ 3.3 $ (2.8 ) $ — $ 76.9 Gas Utility Gas Marketing Other Eliminations Consolidated Three Months Ended December 31, 2019 Operating Revenues: Revenues from external customers $ 530.6 $ 32.3 $ 4.0 $ — $ 566.9 Intersegment revenues 0.1 — 7.1 (7.2 ) — Total Operating Revenues 530.7 32.3 11.1 (7.2 ) 566.9 Operating Expenses: Natural gas 241.5 24.5 0.1 (4.2 ) 261.9 Operation and maintenance 108.6 3.1 7.9 (3.0 ) 116.6 Depreciation and amortization 46.4 — 1.1 — 47.5 Taxes, other than income taxes 37.9 0.3 0.4 — 38.6 Total Operating Expenses 434.4 27.9 9.5 (7.2 ) 464.6 Operating Income $ 96.3 $ 4.4 $ 1.6 $ — $ 102.3 Net Economic Earnings (Loss) $ 69.1 $ 6.1 $ (3.4 ) $ — $ 71.8 The following table reconciles the Company’s net economic earnings to net income. Three Months Ended December 31, 2020 2019 Net Income $ 88.9 $ 67.0 Adjustments, pre-tax: Provision for ISRS rulings — 2.6 Fair value and timing adjustments (16.0 ) 3.7 Income tax effect of adjustments 4.0 (1.5 ) Net Economic Earnings $ 76.9 $ 71.8 The Company’s total assets by segment were as follows: December 31, September 30, December 31, 2020 2020 2019 Total Assets: Gas Utility $ 6,932.3 $ 6,716.2 $ 6,306.0 Gas Marketing 204.8 182.7 242.7 Other 2,462.3 2,443.5 2,450.5 Eliminations (1,083.8 ) (1,101.2 ) (1,038.2 ) Total Assets $ 8,515.6 $ 8,241.2 $ 7,961.0

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. COMMITMENTS AND CONTINGENCIES Commitments The Company and the Utilities have entered into contracts with various counterparties, expiring on dates through 2039, for the storage, transportation, and supply of natural gas. Minimum payments required under the contracts in place at December 31, 2020, are estimated at $1,739.4, $1,319.4, and $310.3 for the Company, Spire Missouri, and Spire Alabama, respectively. Additional contracts are generally entered into prior to or during the heating season of November through April. The Utilities recover their costs from customers in accordance with their PGA clauses or GSA riders. 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 have a material effect on the statements of income, balance sheets, and statements of cash flows of the Company, Spire Missouri, or Spire Alabama. However, there is uncertainty in the valuation of pending claims and prediction of litigation results. 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 materially affected the Company’s or Utilities’ financial position and results of operations. As environmental laws, regulations, and their interpretations change, the Company or the Utilities may incur additional environmental liabilities that may result in additional costs, which may be material. 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. 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. Spire Missouri Spire Missouri has identified three former MGP sites in the city of St. Louis, Missouri (the “City”) where costs have been incurred and claims have been asserted. Spire Missouri has enrolled two of the sites in the Missouri Department of Natural Resources (MDNR) Brownfields/Voluntary Cleanup Program (BVCP). The third site is the result of a relatively new claim assertion by the United States Environmental Protection Agency (EPA). In conjunction with redevelopment of one of the sites, 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 of the City agencies and the environmental consultant to remediate the site and obtain a No Further Action letter from the MDNR. The Remediation Agreement also provides for a release of Spire Missouri and the other former site owner from certain liabilities related to the past and current environmental condition of the site and requires the developer and the environmental consultant to maintain certain insurance coverage, including remediation cost containment, premises pollution liability, and professional liability. The operative provisions of the Remediation Agreement were triggered on December 20, 2010, on which date Spire Missouri and the other former site owner, as full consideration under the Remediation Agreement, paid a small percentage of the cost of remediation of the site. Spire Missouri has not owned the second site for many years. In a letter dated June 29, 2011, the Attorney General for the State of Missouri informed Spire Missouri that the MDNR had completed an investigation of the site. The Attorney General requested that Spire Missouri participate in the follow up investigations of the site. In a letter dated January 10, 2012, Spire Missouri stated that it would participate in future environmental response activities at the site in conjunction with other PRPs that are willing to contribute to such efforts in a meaningful and equitable fashion. Accordingly, Spire Missouri entered into a cost sharing agreement for remedial investigation with other PRPs. To date, MDNR has not approved the agreement, so remedial investigation has not yet occurred. Additionally, in correspondence dated November 30, 2016, Region 7 of the EPA has asserted that Spire Missouri is liable under Section 107(a) of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) for alleged coal gas waste contamination at a third site in the northern portion of the City on which Spire Missouri operated a MGP. Spire Missouri has not owned or operated the site (also known as Station “B”) for over 70 years. Spire Missouri and the site owner have met with the EPA and reviewed its assertions. Both Spire Missouri and the site owner have notified the EPA that information and data provided by the EPA to date does not rise to the level of documenting a threat to the public health or environment. As such, Spire Missouri requested more information from the EPA, some of which would also be utilized to identify other former owners and operators of the site that could be added as PRPs. To date, Spire Missouri has not received a response from the EPA. 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, Spire Missouri received a Section 104(e) information request under CERCLA from EPA Region 7 regarding the former Thompson Chemical/Superior Solvents site in the City. In turn, Spire Missouri issued a Freedom of Information Act (FOIA) request to the EPA on April 3, 2015, in an effort to identify the basis of the inquiry. The FOIA response from the EPA was received on July 15, 2015, and a response was provided to the EPA on August 15, 2015. Spire Missouri has received no further inquiry from the EPA regarding this matter. In its western service area, Spire Missouri has seven owned MGP sites enrolled in the BVCP, including Joplin MGP #1, St. Joseph MGP #1, Kansas City Coal Gas Station B, Kansas City Station A Railroad area, Kansas City Coal Gas Station A North, Kansas City Coal Gas Station A South, and Independence MGP #2. Source removal has been conducted at all of the owned sites since 2003 with the exception of Joplin. On September 15, 2016, a request was made with the MDNR for a restrictive covenant use limitation with respect to Joplin. Remediation efforts at the seven sites are at various stages of completion, ranging from groundwater monitoring and sampling following source removal activities to the aforementioned request in respect to Joplin. As part of its participation in the BVCP, Spire Missouri communicates regularly with the MDNR with respect to its remediation efforts and monitoring activities at these sites. On May 11, 2015, MDNR approved the next phase of investigation at the Kansas City Station A North and Railroad areas. To date, costs incurred for all Spire Missouri’s MGP sites for investigation, remediation and monitoring these sites have not been material. However, the amount of costs relative to future remedial actions at these and other sites is unknown and may be material. The actual future costs that Spire Missouri may incur could be materially higher or lower depending upon several factors, including whether remediation will be required, final selection and regulatory approval of any remedial actions, changing technologies and government regulations, the ultimate ability of other PRPs to pay, and any insurance recoveries. In 2013, Spire Missouri retained an outside consultant to conduct probabilistic cost modeling of 19 former MGP sites owned or operated by Spire Missouri. The purpose of this analysis was to develop an estimated range of probabilistic future liability for each site. That analysis, completed in August 2014, provided a range of demonstrated possible future expenditures to investigate, monitor and remediate all 19 MGP sites. Spire Missouri has recorded its best estimate of the probable expenditures that relate to these matters. The amount is not material. Spire Missouri and the Company do not expect potential liabilities that may arise from remediating these sites to have a material impact on their future financial condition or results of operations. Spire Alabama Spire Alabama is in the chain of title of nine former MGP sites, four of which it still owns, and five former manufactured gas distribution sites, one of which it still owns. Spire Alabama does not foresee a probable or reasonably estimable loss associated with these sites. Spire Alabama and the Company do not expect potential liabilities that may arise from remediating these sites to have a material impact on their future financial condition or results of operations. In 2012, Spire Alabama responded to an EPA Request for Information Pursuant to Section 104 of CERCLA relating to the 35th Avenue Superfund Site located in North Birmingham, Jefferson County, Alabama. Spire Alabama was identified as a PRP under CERCLA for the cleanup of the site or costs the EPA incurs in cleaning up the site. At this point, Spire Alabama has not been provided information that would allow it to determine the extent, if any, of its potential liability with respect to the 35th Avenue Superfund Site and vigorously denies its inclusion as a PRP. Spire In addition to those discussed above for Spire Missouri and Spire Alabama, Spire is aware of the following contingent matter. In February 2018, the Company was made aware of a complaint filed with the U.S. Department of Housing and Urban Development (HUD) by the South Alabama Center for Fair Housing and the National Community Reinvestment Coalition. The complaint alleged that Spire Gulf discriminated against unspecified residents of Eight Mile, Alabama, on the basis of race in violation of the Fair Housing Act by failing to adequately address the odorant release that occurred in 2008. On December 2, 2020, HUD issued a determination that found no reasonable cause exists that Spire Gulf discriminated against residents in Eight Mile, Alabama.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	BASIS OF PRESENTATION – These notes are an integral part of the accompanying unaudited financial statements of Spire Inc. (“Spire” or the “Company”) presented on a consolidated basis, Spire Missouri Inc. (“Spire Missouri”) and Spire Alabama Inc. (“Spire Alabama”). Spire Missouri and Spire Alabama are wholly owned subsidiaries of Spire. Spire Missouri, Spire Alabama and the subsidiaries of Spire EnergySouth Inc. (“Spire EnergySouth”) are collectively referred to as the “Utilities.” The subsidiaries of Spire EnergySouth are Spire Gulf Inc. and Spire Mississippi Inc. 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-Q and Rule 10-01 of Regulation S‑X. Accordingly, they do not include all the disclosures required for complete financial statements. In the opinion of management, the accompanying unaudited financial statements include all adjustments necessary for the fair presentation of the results of operations for the periods presented. This Form 10-Q should be read in conjunction with the Notes to Financial Statements contained in Spire’s, Spire Missouri’s and Spire Alabama’s combined Annual Report on Form 10-K for the fiscal year ended September 30, 2020. 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 been eliminated from their separate financial statements.
Derivatives	DERIVATIVES – In the course of their business, certain subsidiaries of Spire enter into commitments associated with the purchase or sale of natural gas. Certain of their derivative natural gas contracts are designated as normal purchases or normal sales and, as such, are excluded from the scope of Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 815, Derivatives and Hedging . Those contracts are accounted for as executory contracts and recorded on an accrual basis. Revenues and expenses from such contracts are recorded gross. Contracts not designated as normal purchases or normal sales are recorded as derivatives with changes in fair value recognized in earnings in the periods prior to physical delivery. Certain of Spire Marketing’s wholesale purchase and sale transactions are classified as trading activities for financial reporting purposes. Under GAAP, revenues and expenses associated with trading activities are presented on a net basis in Gas Marketing operating revenues (or expenses, if negative) in the Condensed Consolidated Statements of Income. This net presentation has no effect on operating income or net income.
Regulated Operations	REGULATED OPERATIONS – The Utilities account for their regulated operations in accordance with FASB ASC Topic 980, Regulated Operations . This topic sets forth the application of GAAP for those companies whose rates are established by or are subject to approval by an independent third-party regulator. The provisions of this accounting guidance require, among other things, that financial statements of a regulated enterprise reflect the actions of regulators, where appropriate. These actions may result in the recognition of revenues and expenses in time periods that are different than non-regulated enterprises. When this occurs, costs are deferred as assets in the balance sheet (regulatory assets) and recorded as expenses when those amounts are reflected in rates. In addition, regulators can impose liabilities upon a regulated company for amounts previously collected from customers and for recovery of costs that are expected to be incurred in the future (regulatory liabilities). Management believes that the current regulatory environment supports the continued use of these regulatory accounting principles and that all regulatory assets and regulatory liabilities are recoverable or refundable through the regulatory process. 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 4 , Regulatory Matters.
Transactions with Affiliates	TRANSACTIONS WITH AFFILIATES – Transactions between affiliates of the Company have been eliminated from the consolidated financial statements of Spire. Spire Missouri and Spire Alabama borrowed funds from the Company and incurred related interest, as reflected in their separate financial statements, and they participated in normal intercompany shared services transactions. In addition, Spire Missouri’s other transactions with affiliates are presented in the table below: Three Months Ended December 31, 2020 2019 Purchases of natural gas from Spire Marketing Inc. $ 10.7 $ 19.5 Transportation services received from Spire STL Pipeline LLC 8.1 3.9 Sales of natural gas to Spire Marketing Inc. 1.1 — Transportation services received from Spire NGL Inc. 0.3 0.3 In the three months ended December 31, 2020 and 2019, Spire Alabama had purchases of natural gas from Spire Marketing totaling $4.8 and $3.3, respectively.
Accrued Capital Expenditures	ACCRUED CAPITAL EXPENDITURES – Accrued capital expenditures, shown in the following table, are excluded from capital expenditures in the statements of cash flows until paid. December 31, September 30, December 31, 2020 2020 2019 Spire $ 40.9 $ 67.6 $ 45.8 Spire Missouri 23.1 34.3 20.2 Spire Alabama 4.2 17.0 9.8
Accounts Receivable and Allowance For Credit Losses	ACCOUNTS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES – Trade accounts receivable are recorded at the amounts due from customers, including unbilled amounts. Accounts receivable are written off when they are deemed to be uncollectible. An allowance for expected credit losses is estimated and updated based on relevant data and trends such as accounts receivable aging, historical write-off experience, current write-off trends, economic conditions, and the impact of weather and availability of customer payment assistance on collection trends. For the Utilities, net write-offs as a percentage of revenue has historically been the best predictor of base net write-off experience over time. Management judgment is applied in the development of the allowance due to the complexity of variables and subjective nature of certain relevant factors. For December 31, 2020, and September 30, 2020, the estimates for expected credit losses were increased as a result of considerations related to the outbreak of the novel coronavirus (COVID-19), including trends from previous economic downturns, the effects of moratoriums on cutoffs, and the effects of slower-than-normal disconnection activity in general, offset by the amount subject to specific recovery under Missouri’s deferral order (see Note 4 , Regulatory Matters). The accounts receivable of Spire’s non-utility businesses are evaluated separately from those of the Utilities. The allowance for credit losses for those other businesses is based on a continuous evaluation of the individual counterparty risk and is not significant for the periods presented. Activity in the allowance for credit losses for the three months ended December 31, 2020, is shown in the following table. Spire Spire Spire Missouri Alabama Allowance at beginning of period $ 24.9 $ 18.1 $ 5.5 Provision for expected credit losses 4.1 3.3 0.7 Write-offs, net of recoveries (0.1 ) — — Allowance at end of period $ 28.9 $ 21.4 $ 6.2
New Accounting Pronouncements	NEW ACCOUNTING PRONOUNCEMENTS – In June 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments , which was later supplemented by ASU Nos. 2018-19, 2019-04, 2019-05 and 2019-11. The new standard replaces the current “incurred loss” model with an “expected loss” model for certain instruments, including trade receivables, requiring measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. It also required entities to record credit loss allowances for available-for-sale securities rather than impair the carrying amount of the securities. Spire, Spire Missouri and Spire Alabama adopted the new standard for the quarter ended December 31, 2020. Based on the credit quality of the existing available-for-sale securities portfolio, no allowance for credit losses was recognized for those investments. Application of the new guidance did not result in any significant modifications to the Company’s policies related to recognizing an allowance on trade receivables, and the adoption of the new standard did not have a material impact on Spire’s, Spire Missouri’s and Spire Alabama’s financial statements.
Reclassifications	RECLASSIFICATIONS – Spire’s consolidated statements of income historically showed Gas Utility operating revenues and expense line items separately from Gas Marketing and other operations. The current presentation shows operating revenues and expense line items on a consolidated basis. Disaggregated data is presented in Note 9 , Information by Operating Segment. Prior period amounts have been reclassified to conform with the current period presentation.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Schedule of Inter-Company Transactions	In addition, Spire Missouri’s other transactions with affiliates are presented in the table below Three Months Ended December 31, 2020 2019 Purchases of natural gas from Spire Marketing Inc. $ 10.7 $ 19.5 Transportation services received from Spire STL Pipeline LLC 8.1 3.9 Sales of natural gas to Spire Marketing Inc. 1.1 — Transportation services received from Spire NGL Inc. 0.3 0.3
Schedule of Capital Expenditures Excluded from Statement of Cash Flow	Accrued capital expenditures, shown in the following table, are excluded from capital expenditures in the statements of cash flows until paid. December 31, September 30, December 31, 2020 2020 2019 Spire $ 40.9 $ 67.6 $ 45.8 Spire Missouri 23.1 34.3 20.2 Spire Alabama 4.2 17.0 9.8
Schedule of Allowance for Credit Losses	Spire Spire Spire Missouri Alabama Allowance at beginning of period $ 24.9 $ 18.1 $ 5.5 Provision for expected credit losses 4.1 3.3 0.7 Write-offs, net of recoveries (0.1 ) — — Allowance at end of period $ 28.9 $ 21.4 $ 6.2

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Dec. 31, 2020
Revenue From Contract With Customer [Abstract]
Schedule of Revenue Disaggregated by Source and Customer Type	The following tables show revenue disaggregated by source and customer type. Three Months Ended December 31, 2020 2019 Spire Gas Utility: Residential $ 349.9 $ 368.4 Commercial & industrial 103.0 122.5 Transportation 32.2 31.0 Off-system & other incentive 9.3 9.4 Other customer revenue 2.2 2.4 Total revenue from contracts with customers 496.6 533.7 Changes in accrued revenue under alternative revenue programs 1.6 (3.0 ) Total Gas Utility operating revenues 498.2 530.7 Gas Marketing: Revenue from contracts with retail customers 19.4 32.3 Revenue from wholesale derivative contracts 5.4 — Total Gas Marketing operating revenues 24.8 32.3 Other 16.7 11.1 Total before eliminations 539.7 574.1 Intersegment eliminations (see Note 9, Information by Operating Segment) (27.1 ) (7.2 ) Total Operating Revenues $ 512.6 $ 566.9 Spire Missouri Residential $ 263.0 $ 275.9 Commercial & industrial 69.9 80.8 Transportation 9.0 9.0 Off-system & other incentive 7.4 9.4 Other customer revenue 2.9 0.5 Total revenue from contracts with customers 352.2 375.6 Changes in accrued revenue under alternative revenue programs 3.3 (1.6 ) Total Operating Revenues $ 355.5 $ 374.0 Spire Alabama Residential $ 69.2 $ 74.3 Commercial & industrial 24.3 31.3 Transportation 20.5 19.6 Off-system & other incentive 2.0 — Other customer revenue (1.9 ) 1.6 Total revenue from contracts with customers 114.1 126.8 Changes in accrued revenue under alternative revenue programs (0.5 ) (0.6 ) Total Operating Revenues $ 113.6 $ 126.2
Schedule of Gross Receipts Taxes	The expense amounts (shown in the table below) are reported gross in the “Taxes, other than income taxes” line in the statements of income, and corresponding revenues are reported in “Operating Revenues.” Three Months Ended December 31, 2020 2019 Spire $ 21.7 $ 24.6 Spire Missouri 15.2 17.2 Spire Alabama 5.3 6.2

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	3 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Earnings Per Share	Three Months Ended December 31, 2020 2019 Basic Earnings Per Common Share: Net Income $ 88.9 $ 67.0 Less: Provision for preferred dividends 3.7 3.7 Income allocated to participating securities 0.1 0.1 Income Available to Common Shareholders $ 85.1 $ 63.2 Weighted Average Common Shares Outstanding (in millions) 51.5 50.9 Basic Earnings Per Common Share $ 1.65 $ 1.24 Diluted Earnings Per Common Share: Net Income $ 88.9 $ 67.0 Less: Provision for preferred dividends 3.7 3.7 Income allocated to participating securities 0.1 0.1 Income Available to Common Shareholders $ 85.1 $ 63.2 Weighted Average Common Shares Outstanding (in millions) 51.5 50.9 Dilutive Effect of Restricted Stock and Restricted Stock Units (in millions)* 0.1 0.2 Weighted Average Diluted Common Shares (in millions) 51.6 51.1 Diluted Earnings Per Common Share $ 1.65 $ 1.24 * Calculation excludes certain outstanding common shares (shown in millions by period at the right) attributable to stock units subject to performance or market conditions and restricted stock, which could have a dilutive effect in the future 0.2 0.1

Regulatory Matters (Tables)

Regulatory Matters (Tables)	3 Months Ended
	Dec. 31, 2020
Regulated Operations [Abstract]
Schedule of Regulatory Assets and Liabilities	The following regulatory assets and regulatory liabilities were reflected in the balance sheets of the Company, Spire Missouri and Spire Alabama as of December 31, 2020, September 30, 2020, and December 31, 2019. December 31, September 30, December 31, Spire 2020 2020 2019 Regulatory Assets: Current: Pension and postretirement benefit costs $ 30.6 $ 30.6 $ 30.1 Unamortized purchased gas adjustments 8.4 5.5 9.1 Other 31.5 33.4 28.7 Total Current Regulatory Assets 70.5 69.5 67.9 Noncurrent: Pension and postretirement benefit costs 428.6 439.3 405.5 Cost of removal 417.4 395.6 152.1 Future income taxes due from customers 125.4 123.5 111.6 Energy efficiency 41.4 39.6 37.2 Unamortized purchased gas adjustments 3.8 12.1 — Other 62.6 59.3 44.1 Total Noncurrent Regulatory Assets 1,079.2 1,069.4 750.5 Total Regulatory Assets $ 1,149.7 $ 1,138.9 $ 818.4 Regulatory Liabilities: Current: Pension and postretirement benefit costs $ 5.8 $ 5.8 $ 5.8 Unamortized purchased gas adjustments 54.8 73.1 19.9 Other 34.9 34.1 24.3 Total Current Regulatory Liabilities 95.5 113.0 50.0 Noncurrent: Deferred taxes due to customers 136.0 138.8 177.0 Pension and postretirement benefit costs 163.7 157.6 147.5 Accrued cost of removal 28.6 28.6 38.7 Unamortized purchased gas adjustments 14.8 4.4 24.3 Other 14.2 14.3 30.3 Total Noncurrent Regulatory Liabilities 357.3 343.7 417.8 Total Regulatory Liabilities $ 452.8 $ 456.7 $ 467.8 December 31, September 30, December 31, Spire Missouri 2020 2020 2019 Regulatory Assets: Current: Pension and postretirement benefit costs $ 21.9 $ 21.9 $ 21.9 Other 10.2 10.2 7.5 Total Current Regulatory Assets 32.1 32.1 29.4 Noncurrent: Future income taxes due from customers 116.6 114.6 104.9 Pension and postretirement benefit costs 324.6 332.6 324.7 Energy efficiency 41.4 39.6 37.2 Unamortized purchased gas adjustments 3.8 12.1 — Cost of removal 18.3 7.1 — Other 45.7 42.7 24.3 Total Noncurrent Regulatory Assets 550.4 548.7 491.1 Total Regulatory Assets $ 582.5 $ 580.8 $ 520.5 Regulatory Liabilities: Current: Pension and postretirement benefit costs $ 3.6 $ 3.6 $ 3.6 Unamortized purchased gas adjustments 54.3 72.3 19.0 Other 25.5 27.3 19.8 Total Current Regulatory Liabilities 83.4 103.2 42.4 Noncurrent: Deferred taxes due to customers 118.6 121.4 159.7 Pension and postretirement benefit costs 146.1 140.4 124.9 Accrued cost of removal — — 12.1 Unamortized purchased gas adjustments 14.8 4.4 24.3 Other 8.7 8.6 24.5 Total Noncurrent Regulatory Liabilities 288.2 274.8 345.5 Total Regulatory Liabilities $ 371.6 $ 378.0 $ 387.9 December 31, September 30, December 31, Spire Alabama 2020 2020 2019 Regulatory Assets: Current: Pension and postretirement benefit costs $ 7.7 $ 7.7 $ 7.2 Unamortized purchased gas adjustments 8.3 5.5 8.8 Other 6.7 7.2 8.4 Total Current Regulatory Assets 22.7 20.4 24.4 Noncurrent: Pension and postretirement benefit costs 95.7 98.2 74.9 Cost of removal 399.1 388.6 152.1 Future income taxes due from customers 2.2 2.2 — Other 1.2 0.9 3.2 Total Noncurrent Regulatory Assets 498.2 489.9 230.2 Total Regulatory Assets $ 520.9 $ 510.3 $ 254.6 Regulatory Liabilities: Current: Pension and postretirement benefit costs $ 2.2 $ 2.2 $ 2.2 Other 4.7 1.7 0.2 Total Current Regulatory Liabilities 6.9 3.9 2.4 Noncurrent: Pension and postretirement benefit costs 14.7 14.8 18.4 Other 3.7 3.7 3.9 Total Noncurrent Regulatory Liabilities 18.4 18.5 22.3 Total Regulatory Liabilities $ 25.3 $ 22.4 $ 24.7
Schedule of Regulatory Assets Not Earning a Return	A portion of the Company’s and Spire Missouri’s regulatory assets are not earning a return, as shown in the table below: December 31, September 30, December 31, 2020 2020 2019 Spire Pension and postretirement benefit costs $ 229.7 $ 232.3 $ 208.0 Future income taxes due from customers 123.2 121.3 111.6 Other 12.4 12.9 14.1 Total Regulatory Assets Not Earning a Return $ 365.3 $ 366.5 $ 333.7 Spire Missouri Pension and postretirement benefit costs $ 229.7 $ 232.3 $ 208.0 Future income taxes due from customers 116.6 114.6 104.9 Other 12.4 12.9 14.1 Total Regulatory Assets Not Earning a Return $ 358.7 $ 359.8 $ 327.0

Financing Arrangements and Lo_2

Financing Arrangements and Long-term Debt (Tables)	3 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Spire Missouri and Alabama Short-term Borrowings	Information about Spire’s consolidated short-term borrowings and about Spire Missouri’s and Spire Alabama’s borrowings from Spire is presented in the following table. As of December 31, 2020, $455.5 of Spire’s short-term borrowings were used to support lending to the Utilities. Spire (Parent Only) Spire Missouri Spire Alabama Spire Credit Term CP Credit Spire Credit Spire Consol- Facility Loan Program Facility Note Facility Note idated Three Months Ended December 31, 2020 Weighted average borrowings $ — $ 125.5 $ 609.2 $ — $ 341.3 $ — $ 111.6 $ 734.7 Lowest borrowings outstanding — — 497.0 — 292.8 — 1.5 631.1 Highest borrowings outstanding — 150.0 701.1 — 396.7 — 152.2 850.5 Weighted average interest rate n/a 1.1 % 0.2 % n/a 0.2 % n/a 0.2 % 0.4 % As of December 31, 2020 Borrowings outstanding $ — $ — $ 696.1 $ — $ 393.7 $ — $ 27.0 $ 696.1 Weighted average interest rate n/a n/a 0.3 % n/a 0.3 % n/a 0.3 % 0.3 % As of September 30, 2020 Borrowings outstanding $ — $ 150.0 $ 498.0 $ — $ 301.2 $ — $ 121.3 $ 648.0 Weighted average interest rate n/a 1.1 % 0.2 % n/a 0.2 % n/a 0.2 % 0.6 % As of December 31, 2019 Borrowings outstanding $ — $ — $ 518.9 $ — $ 288.1 $ — $ 67.1 $ 518.9 Weighted average interest rate n/a n/a 2.1 % n/a 2.1 % n/a 2.1 % 2.1 %
Summary Capitalized Interest	Interest expense shown on Spire’s consolidated statements of income and Spire Missouri’s statements of comprehensive income is net of the capitalized interest amounts shown in the following table. Three Months Ended December 31, 2020 2019 Spire $ 0.9 $ 2.2 Spire Missouri — 0.3 Spire Alabama 0.6 0.6

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Summary of Financial Instruments Measured at Fair Value on Recurring Basis	The carrying amounts and estimated fair values of financial instruments not measured at fair value on a recurring basis are shown in the following tables, classified according to the fair value hierarchy. There were no such instruments classified as Level 3 (significant unobservable inputs) as of December 31, 2020, September 30, 2020, and December 31, 2019. Classification of Estimated Fair Value Carrying Amount Fair Value Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Spire As of December 31, 2020 Cash and cash equivalents $ 3.5 $ 3.5 $ 3.5 $ — Notes payable 696.1 696.1 — 696.1 Long-term debt, including current portion 2,628.4 3,119.5 — 3,119.5 As of September 30, 2020 Cash and cash equivalents $ 4.1 $ 4.1 $ 4.1 $ — Notes payable 648.0 648.0 — 648.0 Long-term debt, including current portion 2,484.1 2,908.6 — 2,908.6 As of December 31, 2019 Cash and cash equivalents $ 21.5 $ 21.5 $ 21.5 $ — Notes payable 518.9 518.9 — 518.9 Long-term debt, including current portion 2,529.7 2,765.9 — 2,765.9 Spire Missouri As of December 31, 2020 Notes payable – associated companies $ 393.7 $ 393.7 $ — $ 393.7 Long-term debt 1,092.2 1,329.0 — 1,329.0 As of September 30, 2020 Notes payable – $ 301.2 $ 301.2 $ — $ 301.2 Long-term debt 1,092.0 1,313.5 — 1,313.5 As of December 31, 2019 Cash and cash equivalents $ 9.3 $ 9.3 $ 9.3 $ — Notes payable – 288.1 288.1 — 288.1 Long-term debt 1,098.6 1,234.9 — 1,234.9 Spire Alabama As of December 31, 2020 Notes payable – $ 27.0 $ 27.0 $ — $ 27.0 Long-term debt, including current portion 621.0 742.9 — 742.9 As of September 30, 2020 Notes payable – $ 121.3 $ 121.3 $ — $ 121.3 Long-term debt 471.8 576.9 — 576.9 As of December 31, 2019 Notes payable – $ 67.1 $ 67.1 $ — $ 67.1 Long-term debt, including current portion 511.7 572.8 — 572.8

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	Spire Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Effects of Netting and Cash Margin Receivables /Payables Total As of December 31, 2020 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 23.4 $ — $ — $ — $ 23.4 Gasoline and heating oil contracts 0.4 — — (0.4 ) — Gas Marketing: NYMEX/ICE natural gas contracts 0.3 21.5 — (12.4 ) 9.4 Natural gas commodity contracts — 14.9 — — 14.9 Other: U.S. stock/bond mutual funds 14.2 — — — 14.2 Interest rate swaps — 7.0 — — 7.0 Total $ 38.3 $ 43.4 $ — $ (12.8 ) $ 68.9 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 4.9 $ — $ — $ (4.9 ) $ — Gas Marketing: NYMEX/ICE natural gas contracts — 9.2 — (9.2 ) — Natural gas commodity contracts — 12.2 — — 12.2 Other: Interest rate swaps — 44.0 — — 44.0 Total $ 4.9 $ 65.4 $ — $ (14.1 ) $ 56.2 Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Effects of Netting and Cash Margin Receivables /Payables Total As of September 30, 2020 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 21.9 $ — $ — $ — $ 21.9 NYMEX/ICE natural gas contracts 6.3 — — (6.3 ) — Gasoline and heating oil contracts 0.3 — — (0.3 ) — Gas Marketing: NYMEX/ICE natural gas contracts — 27.7 — (25.4 ) 2.3 Natural gas commodity contracts — 14.5 0.4 — 14.9 Other: U.S. stock/bond mutual funds 18.6 — — — 18.6 Total $ 47.1 $ 42.2 $ 0.4 $ (32.0 ) $ 57.7 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 0.9 $ — $ — $ (0.9 ) $ — Gas Marketing: NYMEX/ICE natural gas contracts 0.7 21.4 — (22.1 ) — Natural gas commodity contracts — 22.3 — — 22.3 Other: Interest rate swaps — 54.2 — — 54.2 Total $ 1.6 $ 97.9 $ — $ (23.0 ) $ 76.5 As of December 31, 2019 ASSETS Gas Utility: U.S. stock/bond mutual funds $ 21.2 $ — $ — $ — $ 21.2 Gas Marketing: NYMEX/ICE natural gas contracts 0.6 4.9 — (5.3 ) 0.2 Natural gas commodity contracts — 20.6 — (4.4 ) 16.2 Other: U.S. stock/bond mutual funds 16.6 — — — 16.6 Total $ 38.4 $ 25.5 $ — $ (9.7 ) $ 54.2 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 16.0 $ — $ — $ (16.0 ) $ — Gas Marketing: NYMEX/ICE natural gas contracts 0.4 8.0 — (8.4 ) — Natural gas commodity contracts — 19.5 1.5 (4.4 ) 16.6 Other: Interest rate swaps — 24.5 — — 24.5 Total $ 16.4 $ 52.0 $ 1.5 $ (28.8 ) $ 41.1
Spire Missouri
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	Spire Missouri Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Effects of Netting and Cash Margin Receivables /Payables Total As of December 31, 2020 ASSETS U.S. stock/bond mutual funds $ 23.4 $ — $ — $ — $ 23.4 Gasoline and heating oil contracts 0.4 — — (0.4 ) — Total $ 23.8 $ — $ — $ (0.4 ) $ 23.4 LIABILITIES NYMEX/ICE natural gas contracts $ 4.9 $ — $ — $ (4.9 ) $ — As of September 30, 2020 ASSETS U.S. stock/bond mutual funds $ 21.9 $ — $ — $ — $ 21.9 NYMEX/ICE natural gas contracts 6.3 — — (6.3 ) — Gasoline and heating oil contracts 0.3 — — (0.3 ) — Total $ 28.5 $ — $ — $ (6.6 ) $ 21.9 LIABILITIES NYMEX/ICE natural gas contracts $ 0.9 $ — $ — $ (0.9 ) $ — As of December 31, 2019 ASSETS U.S. stock/bond mutual funds $ 21.2 $ — $ — $ — $ 21.2 LIABILITIES NYMEX/ICE natural gas contracts $ 16.0 $ — $ — $ (16.0 ) $ —

Pension Plans and Other Postr_2

Pension Plans and Other Postretirement Benefits (Tables)	3 Months Ended
	Dec. 31, 2020
Pension Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic cost	The net periodic pension cost included the following components: Three Months Ended December 31, 2020 2019 Spire Service cost – benefits earned during the period $ 5.6 $ 5.5 Interest cost on projected benefit obligation* 5.2 5.9 Expected return on plan assets* (8.0 ) (9.2 ) Amortization of prior service credit* (0.8 ) (0.6 ) Amortization of actuarial loss* 4.0 3.7 Subtotal 6.0 5.3 Regulatory adjustment 9.6 9.6 Net pension cost $ 15.6 $ 14.9 Spire Missouri Service cost – benefits earned during the period $ 3.9 $ 3.8 Interest cost on projected benefit obligation* 3.5 4.2 Expected return on plan assets* (5.6 ) (6.6 ) Amortization of prior service credit* (0.2 ) — Amortization of actuarial loss* 2.9 2.9 Subtotal 4.5 4.3 Regulatory adjustment 7.6 7.7 Net pension cost $ 12.1 $ 12.0 Spire Alabama Service cost – benefits earned during the period $ 1.5 $ 1.5 Interest cost on projected benefit obligation* 1.2 1.2 Expected return on plan assets* (1.6 ) (1.7 ) Amortization of prior service credit* (0.6 ) (0.6 ) Amortization of actuarial loss* 1.1 0.8 Subtotal 1.6 1.2 Regulatory adjustment 1.8 1.7 Net pension cost $ 3.4 $ 2.9 * Denotes pension expense line items that are recorded below the operating income line in the income statements, in the line item “Other Income, Net.”
Other Postretirement Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic cost	Net periodic postretirement benefit costs consisted of the following components: Three Months Ended December 31, 2020 2019 Spire Service cost – benefits earned during the period $ 1.8 $ 1.4 Interest cost on accumulated postretirement benefit obligation* 1.4 1.6 Expected return on plan assets* (4.0 ) (4.1 ) Amortization of prior service cost (credit)* 0.3 (0.2 ) Amortization of actuarial gain* (0.4 ) (0.5 ) Subtotal (0.9 ) (1.8 ) Regulatory adjustment 3.4 4.0 Net postretirement benefit cost $ 2.5 $ 2.2 Spire Missouri Service cost – benefits earned during the period $ 1.6 $ 1.3 Interest cost on accumulated postretirement benefit obligation* 1.1 1.2 Expected return on plan assets* (2.7 ) (2.8 ) Amortization of prior service cost (credit) * 0.2 (0.1 ) Amortization of actuarial gain* (0.4 ) (0.5 ) Subtotal (0.2 ) (0.9 ) Regulatory adjustment 3.8 4.4 Net postretirement benefit cost $ 3.6 $ 3.5 Spire Alabama Service cost – benefits earned during the period $ 0.2 $ 0.1 Interest cost on accumulated postretirement benefit obligation* 0.3 0.3 Expected return on plan assets* (1.2 ) (1.2 ) Amortization of prior service cost (credit)* 0.1 (0.1 ) Subtotal (0.6 ) (0.9 ) Regulatory adjustment (0.4 ) (0.4 ) Net postretirement benefit income $ (1.0 ) $ (1.3 ) * Denotes other postretirement expense line items that are recorded below the operating income line in the income statements, in the line item “Other Income, Net.”

Information by Operating Segm_2

Information by Operating Segment (Tables)	3 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Schedule of Operating Segment Information	Gas Utility Gas Marketing Other Eliminations Consolidated Three Months Ended December 31, 2020 Operating Revenues: Revenues from external customers $ 497.2 $ 10.7 $ 4.7 $ — $ 512.6 Intersegment revenues 1.0 14.1 12.0 (27.1 ) — Total Operating Revenues 498.2 24.8 16.7 (27.1 ) 512.6 Operating Expenses: Natural gas 204.3 0.7 — (23.8 ) 181.2 Operation and maintenance 103.0 3.3 8.6 (3.3 ) 111.6 Depreciation and amortization 48.6 0.3 1.9 — 50.8 Taxes, other than income taxes 35.5 0.2 0.4 — 36.1 Total Operating Expenses 391.4 4.5 10.9 (27.1 ) 379.7 Operating Income $ 106.8 $ 20.3 $ 5.8 $ — $ 132.9 Net Economic Earnings (Loss) $ 76.4 $ 3.3 $ (2.8 ) $ — $ 76.9 Gas Utility Gas Marketing Other Eliminations Consolidated Three Months Ended December 31, 2019 Operating Revenues: Revenues from external customers $ 530.6 $ 32.3 $ 4.0 $ — $ 566.9 Intersegment revenues 0.1 — 7.1 (7.2 ) — Total Operating Revenues 530.7 32.3 11.1 (7.2 ) 566.9 Operating Expenses: Natural gas 241.5 24.5 0.1 (4.2 ) 261.9 Operation and maintenance 108.6 3.1 7.9 (3.0 ) 116.6 Depreciation and amortization 46.4 — 1.1 — 47.5 Taxes, other than income taxes 37.9 0.3 0.4 — 38.6 Total Operating Expenses 434.4 27.9 9.5 (7.2 ) 464.6 Operating Income $ 96.3 $ 4.4 $ 1.6 $ — $ 102.3 Net Economic Earnings (Loss) $ 69.1 $ 6.1 $ (3.4 ) $ — $ 71.8 December 31, September 30, December 31, 2020 2020 2019 Total Assets: Gas Utility $ 6,932.3 $ 6,716.2 $ 6,306.0 Gas Marketing 204.8 182.7 242.7 Other 2,462.3 2,443.5 2,450.5 Eliminations (1,083.8 ) (1,101.2 ) (1,038.2 ) Total Assets $ 8,515.6 $ 8,241.2 $ 7,961.0
Schedule of Reconciliation of Consolidated Net Economic Earnings to Consolidated Net Income	The following table reconciles the Company’s net economic earnings to net income. Three Months Ended December 31, 2020 2019 Net Income $ 88.9 $ 67.0 Adjustments, pre-tax: Provision for ISRS rulings — 2.6 Fair value and timing adjustments (16.0 ) 3.7 Income tax effect of adjustments 4.0 (1.5 ) Net Economic Earnings $ 76.9 $ 71.8

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended
	Dec. 31, 2020USD ($)	Dec. 31, 2020USD ($)reporting_unit	Dec. 31, 2020USD ($)operating-segment	Dec. 31, 2019USD ($)
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Number of reportable segments		2	2
Accounting Standards Update 2016-13
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Credit loss allowances for available-for-sale securities recognized at adoption of ASU	$ 0	$ 0	$ 0
Change in accounting principle, accounting standards update, adopted	true	true	true
Change in accounting principle, accounting standards update, adoption date	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2020
Change in accounting principle, accounting standards update, material effect	true	true	true
Spire Alabama | Accounting Standards Update 2016-13
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Credit loss allowances for available-for-sale securities recognized at adoption of ASU	$ 0	$ 0	$ 0
Change in accounting principle, accounting standards update, adopted	true	true	true
Change in accounting principle, accounting standards update, adoption date	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2020
Change in accounting principle, accounting standards update, material effect	true	true	true
Spire Alabama | Affiliated Entity | Spire Marketing | Regulated Operation
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Purchases of natural gas from related party	$ 4,800,000			$ 3,300,000
Spire Missouri | Accounting Standards Update 2016-13
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Credit loss allowances for available-for-sale securities recognized at adoption of ASU	$ 0	$ 0	$ 0
Change in accounting principle, accounting standards update, adopted	true	true	true
Change in accounting principle, accounting standards update, adoption date	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2020
Change in accounting principle, accounting standards update, material effect	true	true	true

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Inter-Company Transactions (Details) - Affiliated Entity - Spire Missouri - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Spire Marketing Inc | Regulated Operation
Related Party Transaction [Line Items]
Purchases of natural gas from related party	$ 10.7	$ 19.5
Sales of natural gas to Spire Marketing Inc.	1.1
Spire STL Pipeline LLC | Unregulated Operation
Related Party Transaction [Line Items]
Transportation services received	8.1	3.9
Spire NGL Inc. | Unregulated Operation
Related Party Transaction [Line Items]
Transportation services received	$ 0.3	$ 0.3

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Accrued Capital Expenditures (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2020
Schedule Of Accrued Capital Expenditures Excluded From Statement Of Cash Flow [Line Items]
Accruals for capital expenditures	$ 40.9	$ 45.8	$ 67.6
Spire Missouri
Schedule Of Accrued Capital Expenditures Excluded From Statement Of Cash Flow [Line Items]
Accruals for capital expenditures	23.1	20.2	34.3
Spire Alabama
Schedule Of Accrued Capital Expenditures Excluded From Statement Of Cash Flow [Line Items]
Accruals for capital expenditures	$ 4.2	$ 9.8	$ 17

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Schedule of Allowance for Credit Losses (Details) $ in Millions	3 Months Ended
	Dec. 31, 2020USD ($)
Accounts Notes And Loans Receivable [Line Items]
Allowance at beginning of period	$ 24.9
Provision for expected credit losses	4.1
Write-offs, net of recoveries	(0.1)
Allowance at end of period	28.9
Spire Missouri
Accounts Notes And Loans Receivable [Line Items]
Allowance at beginning of period	18.1
Provision for expected credit losses	3.3
Allowance at end of period	21.4
Spire Alabama
Accounts Notes And Loans Receivable [Line Items]
Allowance at beginning of period	5.5
Provision for expected credit losses	0.7
Allowance at end of period	$ 6.2

Revenue - Schedule of Revenue D

Revenue - Schedule of Revenue Disaggregated by Source and Customer Type (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disaggregation Of Revenue [Line Items]
Total operating revenues	$ 512.6	$ 566.9
Intersegment Eliminations
Disaggregation Of Revenue [Line Items]
Total operating revenues	(27.1)	(7.2)
Gas Utility
Disaggregation Of Revenue [Line Items]
Total operating revenues	497.2	530.6
Gas Utility | Operating Segments
Disaggregation Of Revenue [Line Items]
Total operating revenues	498.2	530.7
Gas Utility | Intersegment Eliminations
Disaggregation Of Revenue [Line Items]
Total operating revenues	1	0.1
Gas Marketing
Disaggregation Of Revenue [Line Items]
Total operating revenues	10.7	32.3
Gas Marketing | Operating Segments
Disaggregation Of Revenue [Line Items]
Total operating revenues	24.8	32.3
Gas Marketing | Intersegment Eliminations
Disaggregation Of Revenue [Line Items]
Total operating revenues	14.1	0
Spire
Disaggregation Of Revenue [Line Items]
Total operating revenues	512.6	566.9
Spire | Operating Segments
Disaggregation Of Revenue [Line Items]
Total operating revenues	539.7	574.1
Spire | Intersegment Eliminations
Disaggregation Of Revenue [Line Items]
Total operating revenues	(27.1)	(7.2)
Spire | Gas Utility | Operating Segments
Disaggregation Of Revenue [Line Items]
Total operating revenues	496.6	533.7
Changes in accrued revenue under alternative revenue programs	1.6	(3)
Total operating revenues	498.2	530.7
Spire | Gas Utility | Operating Segments | Residential
Disaggregation Of Revenue [Line Items]
Total operating revenues	349.9	368.4
Spire | Gas Utility | Operating Segments | Commercial & Industrial
Disaggregation Of Revenue [Line Items]
Total operating revenues	103	122.5
Spire | Gas Utility | Operating Segments | Transportation
Disaggregation Of Revenue [Line Items]
Total operating revenues	32.2	31
Spire | Gas Utility | Operating Segments | Off-system & Other Incentive
Disaggregation Of Revenue [Line Items]
Total operating revenues	9.3	9.4
Spire | Gas Utility | Operating Segments | Other Customer Revenue
Disaggregation Of Revenue [Line Items]
Total operating revenues	2.2	2.4
Spire | Gas Marketing | Operating Segments
Disaggregation Of Revenue [Line Items]
Total operating revenues	24.8	32.3
Spire | Gas Marketing | Operating Segments | Revenue From Contracts With Retail Customers
Disaggregation Of Revenue [Line Items]
Total operating revenues	19.4	32.3
Spire | Gas Marketing | Operating Segments | Revenue From Wholesale Derivative Contracts
Disaggregation Of Revenue [Line Items]
Total operating revenues	5.4
Spire | Other | Operating Segments
Disaggregation Of Revenue [Line Items]
Total operating revenues	$ 16.7	$ 11.1

Revenue - Schedule of Operating

Revenue - Schedule of Operating Revenue Information (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disaggregation Of Revenue [Line Items]
Total operating revenues	$ 512.6	$ 566.9
Spire Missouri
Disaggregation Of Revenue [Line Items]
Total operating revenues	352.2	375.6
Changes in accrued revenue under alternative revenue programs	3.3	(1.6)
Total operating revenues	355.5	374
Spire Missouri | Residential
Disaggregation Of Revenue [Line Items]
Total operating revenues	263	275.9
Spire Missouri | Commercial & Industrial
Disaggregation Of Revenue [Line Items]
Total operating revenues	69.9	80.8
Spire Missouri | Transportation
Disaggregation Of Revenue [Line Items]
Total operating revenues	9	9
Spire Missouri | Off-system & Other Incentive
Disaggregation Of Revenue [Line Items]
Total operating revenues	7.4	9.4
Spire Missouri | Other Customer Revenue
Disaggregation Of Revenue [Line Items]
Total operating revenues	2.9	0.5
Spire Alabama
Disaggregation Of Revenue [Line Items]
Total operating revenues	114.1	126.8
Changes in accrued revenue under alternative revenue programs	(0.5)	(0.6)
Total operating revenues	113.6	126.2
Spire Alabama | Residential
Disaggregation Of Revenue [Line Items]
Total operating revenues	69.2	74.3
Spire Alabama | Commercial & Industrial
Disaggregation Of Revenue [Line Items]
Total operating revenues	24.3	31.3
Spire Alabama | Transportation
Disaggregation Of Revenue [Line Items]
Total operating revenues	20.5	19.6
Spire Alabama | Off-system & Other Incentive
Disaggregation Of Revenue [Line Items]
Total operating revenues	2
Spire Alabama | Other Customer Revenue
Disaggregation Of Revenue [Line Items]
Total operating revenues	$ (1.9)	$ 1.6

Revenue - Additional Informatio

Revenue - Additional Information (Details) $ in Millions	3 Months Ended
	Dec. 31, 2020USD ($)
Spire Alabama
Disaggregation Of Revenue [Line Items]
Public utilities requested rate increase decrease amount	$ 3.4

Revenue - Schedule of Gross Rec

Revenue - Schedule of Gross Receipts Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Scheduleof Gross Receipts Taxes [Line Items]
Gross receipts taxes recorded in regulated gas distribution operating revenues	$ 21.7	$ 24.6
Spire Missouri
Scheduleof Gross Receipts Taxes [Line Items]
Gross receipts taxes recorded in regulated gas distribution operating revenues	15.2	17.2
Spire Alabama
Scheduleof Gross Receipts Taxes [Line Items]
Gross receipts taxes recorded in regulated gas distribution operating revenues	$ 5.3	$ 6.2

Earnings Per Common Share - Sch

Earnings Per Common Share - Schedule of Basic and Diluted Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Basic Earnings Per Common Share:
Net Income	$ 88.9	$ 67
Less: Provision for preferred dividends	3.7	3.7
Income allocated to participating securities	0.1	0.1
Net Income Available to Common Shareholders	$ 85.1	$ 63.2
Weighted Average Common Shares Outstanding (in millions)	51.5	50.9
Basic Earnings Per Common Share	$ 1.65	$ 1.24
Diluted Earnings Per Common Share:
Net Income	$ 88.9	$ 67
Less: Provision for preferred dividends	3.7	3.7
Income allocated to participating securities	0.1	0.1
Income Available to Common Shareholders	$ 85.1	$ 63.2
Weighted Average Common Shares Outstanding (in millions)	51.5	50.9
Dilutive Effect of Restricted Stock and Restricted Stock Units (in millions)	0.1	0.2
Weighted Average Diluted Common Shares (in millions)	51.6	51.1
Diluted Earnings Per Common Share	$ 1.65	$ 1.24

Earnings Per Common Share - S_2

Earnings Per Common Share - Schedule of Basic and Diluted Earnings Per Common Share (Parenthetical) (Details) - shares shares in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Restricted Stock and Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding common shares excluded from calculation of diluted EPS (in shares)	0.2	0.1

Regulatory Matters - Schedule o

Regulatory Matters - Schedule of Regulatory Assets and Liabilities, Reflected in Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, current	$ 70.5	$ 69.5	$ 67.9
Regulatory assets, non current	1,079.2	1,069.4	750.5
Total Regulatory Assets	1,149.7	1,138.9	818.4
Regulatory liabilities, current	95.5	113	50
Regulatory liabilities, non current	357.3	343.7	417.8
Total Regulatory Liabilities	452.8	456.7	467.8
Spire Missouri
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, current	32.1	32.1	29.4
Regulatory assets, non current	550.4	548.7	491.1
Total Regulatory Assets	582.5	580.8	520.5
Regulatory liabilities, current	83.4	103.2	42.4
Regulatory liabilities, non current	288.2	274.8	345.5
Total Regulatory Liabilities	371.6	378	387.9
Spire Alabama
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, current	22.7	20.4	24.4
Regulatory assets, non current	498.2	489.9	230.2
Total Regulatory Assets	520.9	510.3	254.6
Regulatory liabilities, current	6.9	3.9	2.4
Regulatory liabilities, non current	18.4	18.5	22.3
Total Regulatory Liabilities	25.3	22.4	24.7
Pension and Other Postretirement Benefits
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, current	30.6	30.6	30.1
Regulatory assets, non current	428.6	439.3	405.5
Pension and Other Postretirement Benefits | Spire Missouri
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, current	21.9	21.9	21.9
Regulatory assets, non current	324.6	332.6	324.7
Pension and Other Postretirement Benefits | Spire Alabama
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, current	7.7	7.7	7.2
Regulatory assets, non current	95.7	98.2	74.9
Unamortized Purchased Gas Adjustments
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, current	8.4	5.5	9.1
Regulatory assets, non current	3.8	12.1	0
Unamortized Purchased Gas Adjustments | Spire Missouri
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, non current	3.8	12.1	0
Unamortized Purchased Gas Adjustments | Spire Alabama
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, current	8.3	5.5	8.8
Other
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, current	31.5	33.4	28.7
Regulatory assets, non current	62.6	59.3	44.1
Other | Spire Missouri
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, current	10.2	10.2	7.5
Regulatory assets, non current	45.7	42.7	24.3
Other | Spire Alabama
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, current	6.7	7.2	8.4
Regulatory assets, non current	1.2	0.9	3.2
Future Income Taxes Due from Customers
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, non current	125.4	123.5	111.6
Future Income Taxes Due from Customers | Spire Missouri
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, non current	116.6	114.6	104.9
Future Income Taxes Due from Customers | Spire Alabama
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, non current	2.2	2.2	0
Accrued Cost of Removal
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, non current	417.4	395.6	152.1
Accrued Cost of Removal | Spire Missouri
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, non current	18.3	7.1	0
Accrued Cost of Removal | Spire Alabama
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, non current	399.1	388.6	152.1
Energy Efficiency
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, non current	41.4	39.6	37.2
Energy Efficiency | Spire Missouri
Regulatory Asset And Liabilities [Line Items]
Regulatory assets, non current	41.4	39.6	37.2
Pension and Other Postretirement Benefits
Regulatory Asset And Liabilities [Line Items]
Regulatory liabilities, current	5.8	5.8	5.8
Regulatory liabilities, non current	163.7	157.6	147.5
Pension and Other Postretirement Benefits | Spire Missouri
Regulatory Asset And Liabilities [Line Items]
Regulatory liabilities, current	3.6	3.6	3.6
Regulatory liabilities, non current	146.1	140.4	124.9
Pension and Other Postretirement Benefits | Spire Alabama
Regulatory Asset And Liabilities [Line Items]
Regulatory liabilities, current	2.2	2.2	2.2
Regulatory liabilities, non current	14.7	14.8	18.4
Unamortized Purchased Gas Adjustments
Regulatory Asset And Liabilities [Line Items]
Regulatory liabilities, current	54.8	73.1	19.9
Regulatory liabilities, non current	14.8	4.4	24.3
Unamortized Purchased Gas Adjustments | Spire Missouri
Regulatory Asset And Liabilities [Line Items]
Regulatory liabilities, current	54.3	72.3	19
Regulatory liabilities, non current	14.8	4.4	24.3
Other
Regulatory Asset And Liabilities [Line Items]
Regulatory liabilities, current	34.9	34.1	24.3
Regulatory liabilities, non current	14.2	14.3	30.3
Other | Spire Missouri
Regulatory Asset And Liabilities [Line Items]
Regulatory liabilities, current	25.5	27.3	19.8
Regulatory liabilities, non current	8.7	8.6	24.5
Other | Spire Alabama
Regulatory Asset And Liabilities [Line Items]
Regulatory liabilities, current	4.7	1.7	0.2
Regulatory liabilities, non current	3.7	3.7	3.9
Deferred Taxes Due to Customers
Regulatory Asset And Liabilities [Line Items]
Regulatory liabilities, non current	136	138.8	177
Deferred Taxes Due to Customers | Spire Missouri
Regulatory Asset And Liabilities [Line Items]
Regulatory liabilities, non current	118.6	121.4	159.7
Accrued Cost of Removal
Regulatory Asset And Liabilities [Line Items]
Regulatory liabilities, non current	28.6	28.6	38.7
Accrued Cost of Removal | Spire Missouri
Regulatory Asset And Liabilities [Line Items]
Regulatory liabilities, non current	$ 0	$ 0	$ 12.1

Regulatory Matters - Schedule_2

Regulatory Matters - Schedule of Regulatory Assets Not Earning a Return (Details) - USD ($) $ in Millions	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	$ 365.3	$ 366.5	$ 333.7
Pension and Other Postretirement Benefits
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	229.7	232.3	208
Future Income Taxes Due from Customers
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	123.2	121.3	111.6
Other
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	12.4	12.9	14.1
Spire Missouri
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	358.7	359.8	327
Spire Missouri | Pension and Other Postretirement Benefits
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	229.7	232.3	208
Spire Missouri | Future Income Taxes Due from Customers
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	116.6	114.6	104.9
Spire Missouri | Other
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	$ 12.4	$ 12.9	$ 14.1

Regulatory Matters - Additional

Regulatory Matters - Additional Information (Details) - USD ($) $ in Millions	Dec. 11, 2020	Apr. 25, 2018	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2020
Public Utilities, General Disclosures [Line Items]
Remaining recovery period for certain regulatory assets for which no return on investment during recovery period is provided (in years)			20 years
Remaining recovery period for regulatory assets for which no return on investment during recovery period is provided (in years)			15 years
Regulatory assets, current			$ 70.5	$ 67.9	$ 69.5
Spire Missouri
Public Utilities, General Disclosures [Line Items]
Regulatory assets, current			32.1	29.4	32.1
MoPSC
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount	$ 64.2				2,780
Public utilities requested rate increase decrease amount	$ 111.5
Common equity ratio	54.25%
Requested return rate on equity	9.95%
Infrastructure System Replacement Surcharge | MoPSC
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease), costs from buildings sold in 2014 excluded from rate base		$ (1.8)
Rate case expenses		(0.9)
Public utilities requested rate increase decrease amount	$ 47.3
Infrastructure System Replacement Surcharge | MoPSC | Spire Missouri
Public Utilities, General Disclosures [Line Items]
Provision for regulatory liability				2.1
Provision for interest				0.5
After-tax impact on loss contingency provision reducing net income				$ 2
Accounting Authority Order | MoPSC
Public Utilities, General Disclosures [Line Items]
Regulatory assets, current			$ 3.9		$ 3.8
Pension Cost | Infrastructure System Replacement Surcharge | MoPSC
Public Utilities, General Disclosures [Line Items]
Regulatory assets recovery		$ (28.8)

Financing Arrangements and Lo_3

Financing Arrangements and Long-term Debt - Additional Information (Details)	Dec. 15, 2020USD ($)	Mar. 26, 2020USD ($)bank	Dec. 31, 2020USD ($)	Dec. 14, 2016bank
Line of Credit Facility [Line Items]
Long-term Debt			$ 975,000,000
Liabilities | Lender Concentration Risk
Line of Credit Facility [Line Items]
Line of credit facility, number of banks in agreement | bank				11
Spire
Line of Credit Facility [Line Items]
Term loan bear interest rate per annum			0.40%
Short-term borrowings used to support lending to Utilities			$ 455,500,000
Spire | Term Loan
Line of Credit Facility [Line Items]
Line of credit facility, number of banks in agreement | bank		2
Long-term Debt		$ 150,000,000
Team loan interest rate description			The term loan bore interest at the LIBOR Rate (as defined in the loan agreement) plus 0.85% per annum.
Term loan bear interest rate per annum			1.10%
Spire | Term Loan | LIBOR
Line of Credit Facility [Line Items]
Term loan bear interest rate per annum		0.85%
Spire Alabama | Senior Notes | Private Placement | Series 2020 Senior Notes due 2030
Line of Credit Facility [Line Items]
Long-term debt	$ 150,000,000
Stated interest rate	2.04%
Debt instrument, maturity date	Dec. 15, 2030
Debt instrument, payment terms			Interest is payable semi-annually.
Revolving Credit Facility Borrowings
Line of Credit Facility [Line Items]
Line of credit facility borrowing capacity			$ 975,000,000
Minimum required ratio of earnings before interest, taxes, depreciation, and amortization (EBITDA) times interest expense as required by the line of credit covenant			70.00%
Revolving Credit Facility Borrowings | Maximum
Line of Credit Facility [Line Items]
Debt to total capitalization ratio			0.60
Revolving Credit Facility Borrowings | Spire
Line of Credit Facility [Line Items]
Line of credit facility borrowing capacity			$ 300,000,000
Revolving Credit Facility Borrowings | Spire Missouri
Line of Credit Facility [Line Items]
Line of credit facility borrowing capacity			475,000,000
Revolving Credit Facility Borrowings | Spire Alabama
Line of Credit Facility [Line Items]
Line of credit facility borrowing capacity			200,000,000
Commercial Paper Notes
Line of Credit Facility [Line Items]
Line of credit facility borrowing capacity			$ 975,000,000
Debt term			365 days
Commercial Paper Notes | Spire
Line of Credit Facility [Line Items]
Term loan bear interest rate per annum			0.20%

Financing Arrangements and Lo_4

Financing Arrangements and Long-term Debt - Schedule of Spire Missouri and Alabama Short-term Borrowings (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Spire Alabama | Spire Note
Short-term Debt [Line Items]
Weighted average borrowings	$ 111.6
Lowest borrowings outstanding	1.5
Highest borrowings outstanding	$ 152.2
Weighted average interest rate	0.20%
Borrowings outstanding	$ 27	$ 121.3	$ 67.1
Weighted average interest rate	0.30%	0.20%	2.10%
Spire Missouri | Spire Note
Short-term Debt [Line Items]
Weighted average borrowings	$ 341.3
Lowest borrowings outstanding	292.8
Highest borrowings outstanding	$ 396.7
Weighted average interest rate	0.20%
Borrowings outstanding	$ 393.7	$ 301.2	$ 288.1
Weighted average interest rate	0.30%	0.20%	2.10%
Spire
Short-term Debt [Line Items]
Weighted average borrowings	$ 734.7
Lowest borrowings outstanding	631.1
Highest borrowings outstanding	$ 850.5
Weighted average interest rate	0.40%
Borrowings outstanding	$ 696.1	$ 648	$ 518.9
Weighted average interest rate	0.30%	0.60%	2.10%
Spire | Term Loan
Short-term Debt [Line Items]
Weighted average borrowings	$ 125.5
Highest borrowings outstanding	$ 150
Weighted average interest rate	1.10%
Borrowings outstanding		$ 150
Weighted average interest rate		1.10%
Spire | Commercial Paper Notes
Short-term Debt [Line Items]
Weighted average borrowings	$ 609.2
Lowest borrowings outstanding	497
Highest borrowings outstanding	$ 701.1
Weighted average interest rate	0.20%
Borrowings outstanding	$ 696.1	$ 498	$ 518.9
Weighted average interest rate	0.30%	0.20%	2.10%

Financing Arrangements and Lo_5

Financing Arrangements and Long-term Debt - Summary of Net of Capitalized Interest (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Spire Missouri
Line of Credit Facility [Line Items]
Interest expense, net		$ 0.3
Spire Alabama
Line of Credit Facility [Line Items]
Interest expense, net	$ 0.6	0.6
Spire
Line of Credit Facility [Line Items]
Interest expense, net	$ 0.9	$ 2.2

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Summary of Financial Instruments Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Quoted Prices in Active Markets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 3.5	$ 4.1	$ 21.5
Quoted Prices in Active Markets (Level 1) | Spire Missouri
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents			9.3
Significant Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes payable	696.1	648	518.9
Long-term debt, including current portion	3,119.5	2,908.6	2,765.9
Significant Observable Inputs (Level 2) | Spire Missouri
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes payable	393.7	301.2	288.1
Long-term debt, including current portion	1,329	1,313.5	1,234.9
Significant Observable Inputs (Level 2) | Spire Alabama
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes payable	27	121.3	67.1
Long-term debt, including current portion	742.9	576.9	572.8
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	3.5	4.1	21.5
Notes payable	696.1	648	518.9
Long-term debt, including current portion	2,628.4	2,484.1	2,529.7
Carrying Amount | Spire Missouri
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents			9.3
Notes payable	393.7	301.2	288.1
Long-term debt, including current portion	1,092.2	1,092	1,098.6
Carrying Amount | Spire Alabama
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes payable	27	121.3	67.1
Long-term debt, including current portion	621	471.8	511.7
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	3.5	4.1	21.5
Notes payable	696.1	648	518.9
Long-term debt, including current portion	3,119.5	2,908.6	2,765.9
Fair Value | Spire Missouri
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents			9.3
Notes payable	393.7	301.2	288.1
Long-term debt, including current portion	1,329	1,313.5	1,234.9
Fair Value | Spire Alabama
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes payable	27	121.3	67.1
Long-term debt, including current portion	$ 742.9	$ 576.9	$ 572.8

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
ASSETS
Effects of netting and cash margin receivables/payables	$ (12.8)	$ (32)	$ (9.7)
Derivative asset after the effects of netting	68.9	57.7	54.2
LIABILITIES
Effects of netting and cash margin receivables/payables	(14.1)	(23)	(28.8)
Derivative liability after the effects of netting	56.2	76.5	41.1
Spire Missouri
ASSETS
Effects of netting and cash margin receivables/payables	(0.4)	(6.6)
Derivative asset after the effects of netting	23.4	21.9
U.S. stock/bond mutual funds | Spire Missouri
ASSETS
Effects of netting and cash margin receivables/payables	0	0	0
Derivative asset after the effects of netting	23.4	21.9	21.2
Gasoline and heating oil contracts | Spire Missouri
ASSETS
Effects of netting and cash margin receivables/payables	(0.4)	(0.3)
Derivative asset after the effects of netting	0	0
NYMEX/ICE natural gas contracts | Spire Missouri
ASSETS
Effects of netting and cash margin receivables/payables		(6.3)
Derivative asset after the effects of netting		0
LIABILITIES
Effects of netting and cash margin receivables/payables	(4.9)	(0.9)	(16)
Derivative liability after the effects of netting	0	0	0
Other | U.S. stock/bond mutual funds
ASSETS
Effects of netting and cash margin receivables/payables	0	0	0
Derivative asset after the effects of netting	14.2	18.6	16.6
Other | Interest Rate Swap
ASSETS
Effects of netting and cash margin receivables/payables	0
Derivative asset after the effects of netting	7
LIABILITIES
Effects of netting and cash margin receivables/payables	0	0	0
Derivative liability after the effects of netting	44	54.2	24.5
Gas Utility | Operating Segments | U.S. stock/bond mutual funds
ASSETS
Effects of netting and cash margin receivables/payables	0	0	0
Derivative asset after the effects of netting	23.4	21.9	21.2
Gas Utility | Operating Segments | Gasoline and heating oil contracts
ASSETS
Effects of netting and cash margin receivables/payables	(0.4)	(0.3)
Derivative asset after the effects of netting	0	0
Gas Utility | Operating Segments | NYMEX/ICE natural gas contracts
ASSETS
Effects of netting and cash margin receivables/payables		(6.3)
Derivative asset after the effects of netting		0
LIABILITIES
Effects of netting and cash margin receivables/payables	(4.9)	(0.9)	(16)
Derivative liability after the effects of netting	0	0	0
Gas Marketing | Operating Segments | NYMEX/ICE natural gas contracts
ASSETS
Effects of netting and cash margin receivables/payables	(12.4)	(25.4)	(5.3)
Derivative asset after the effects of netting	9.4	2.3	0.2
LIABILITIES
Effects of netting and cash margin receivables/payables	(9.2)	(22.1)	(8.4)
Derivative liability after the effects of netting	0	0	0
Gas Marketing | Operating Segments | Natural gas commodity contracts
ASSETS
Effects of netting and cash margin receivables/payables	0	0	(4.4)
Derivative asset after the effects of netting	14.9	14.9	16.2
LIABILITIES
Effects of netting and cash margin receivables/payables	0	0	(4.4)
Derivative liability after the effects of netting	12.2	22.3	16.6
Quoted Prices in Active Markets (Level 1)
ASSETS
Derivative asset before effects of netting	38.3	47.1	38.4
LIABILITIES
Derivative liability before effects of netting	4.9	1.6	16.4
Quoted Prices in Active Markets (Level 1) | Spire Missouri
ASSETS
Derivative asset before effects of netting	23.8	28.5
Quoted Prices in Active Markets (Level 1) | U.S. stock/bond mutual funds | Spire Missouri
ASSETS
Derivative asset before effects of netting	23.4	21.9	21.2
Quoted Prices in Active Markets (Level 1) | Gasoline and heating oil contracts | Spire Missouri
ASSETS
Derivative asset before effects of netting	0.4	0.3
Quoted Prices in Active Markets (Level 1) | NYMEX/ICE natural gas contracts | Spire Missouri
ASSETS
Derivative asset before effects of netting		6.3
LIABILITIES
Derivative liability before effects of netting	4.9	0.9	16
Quoted Prices in Active Markets (Level 1) | Other | U.S. stock/bond mutual funds
ASSETS
Derivative asset before effects of netting	14.2	18.6	16.6
Quoted Prices in Active Markets (Level 1) | Other | Interest Rate Swap
ASSETS
Derivative asset before effects of netting	0
LIABILITIES
Derivative liability before effects of netting	0	0	0
Quoted Prices in Active Markets (Level 1) | Gas Utility | Operating Segments | U.S. stock/bond mutual funds
ASSETS
Derivative asset before effects of netting	23.4	21.9	21.2
Quoted Prices in Active Markets (Level 1) | Gas Utility | Operating Segments | Gasoline and heating oil contracts
ASSETS
Derivative asset before effects of netting	0.4	0.3
Quoted Prices in Active Markets (Level 1) | Gas Utility | Operating Segments | NYMEX/ICE natural gas contracts
ASSETS
Derivative asset before effects of netting		6.3
LIABILITIES
Derivative liability before effects of netting	4.9	0.9	16
Quoted Prices in Active Markets (Level 1) | Gas Marketing | Operating Segments | NYMEX/ICE natural gas contracts
ASSETS
Derivative asset before effects of netting	0.3	0	0.6
LIABILITIES
Derivative liability before effects of netting	0	0.7	0.4
Quoted Prices in Active Markets (Level 1) | Gas Marketing | Operating Segments | Natural gas commodity contracts
ASSETS
Derivative asset before effects of netting	0	0	0
LIABILITIES
Derivative liability before effects of netting	0	0	0
Significant Observable Inputs (Level 2)
ASSETS
Derivative asset before effects of netting	43.4	42.2	25.5
LIABILITIES
Derivative liability before effects of netting	65.4	97.9	52
Significant Observable Inputs (Level 2) | Spire Missouri
ASSETS
Derivative asset before effects of netting	0	0
Significant Observable Inputs (Level 2) | U.S. stock/bond mutual funds | Spire Missouri
ASSETS
Derivative asset before effects of netting	0	0	0
Significant Observable Inputs (Level 2) | Gasoline and heating oil contracts | Spire Missouri
ASSETS
Derivative asset before effects of netting	0	0
Significant Observable Inputs (Level 2) | NYMEX/ICE natural gas contracts | Spire Missouri
ASSETS
Derivative asset before effects of netting		0
LIABILITIES
Derivative liability before effects of netting	0	0	0
Significant Observable Inputs (Level 2) | Other | U.S. stock/bond mutual funds
ASSETS
Derivative asset before effects of netting	0	0	0
Significant Observable Inputs (Level 2) | Other | Interest Rate Swap
ASSETS
Derivative asset before effects of netting	7
LIABILITIES
Derivative liability before effects of netting	44	54.2	24.5
Significant Observable Inputs (Level 2) | Gas Utility | Operating Segments | U.S. stock/bond mutual funds
ASSETS
Derivative asset before effects of netting	0	0	0
Significant Observable Inputs (Level 2) | Gas Utility | Operating Segments | Gasoline and heating oil contracts
ASSETS
Derivative asset before effects of netting	0	0
Significant Observable Inputs (Level 2) | Gas Utility | Operating Segments | NYMEX/ICE natural gas contracts
ASSETS
Derivative asset before effects of netting		0
LIABILITIES
Derivative liability before effects of netting	0	0	0
Significant Observable Inputs (Level 2) | Gas Marketing | Operating Segments | NYMEX/ICE natural gas contracts
ASSETS
Derivative asset before effects of netting	21.5	27.7	4.9
LIABILITIES
Derivative liability before effects of netting	9.2	21.4	8
Significant Observable Inputs (Level 2) | Gas Marketing | Operating Segments | Natural gas commodity contracts
ASSETS
Derivative asset before effects of netting	14.9	14.5	20.6
LIABILITIES
Derivative liability before effects of netting	12.2	22.3	19.5
Significant Unobservable Inputs (Level 3)
ASSETS
Derivative asset before effects of netting	0	0.4	0
LIABILITIES
Derivative liability before effects of netting	0	0	1.5
Significant Unobservable Inputs (Level 3) | Spire Missouri
ASSETS
Derivative asset before effects of netting	0	0
Significant Unobservable Inputs (Level 3) | U.S. stock/bond mutual funds | Spire Missouri
ASSETS
Derivative asset before effects of netting	0	0	0
Significant Unobservable Inputs (Level 3) | Gasoline and heating oil contracts | Spire Missouri
ASSETS
Derivative asset before effects of netting	0	0
Significant Unobservable Inputs (Level 3) | NYMEX/ICE natural gas contracts | Spire Missouri
ASSETS
Derivative asset before effects of netting		0
LIABILITIES
Derivative liability before effects of netting	0	0	0
Significant Unobservable Inputs (Level 3) | Other | U.S. stock/bond mutual funds
ASSETS
Derivative asset before effects of netting	0	0	0
Significant Unobservable Inputs (Level 3) | Other | Interest Rate Swap
ASSETS
Derivative asset before effects of netting	0
LIABILITIES
Derivative liability before effects of netting	0	0	0
Significant Unobservable Inputs (Level 3) | Gas Utility | Operating Segments | U.S. stock/bond mutual funds
ASSETS
Derivative asset before effects of netting	0	0	0
Significant Unobservable Inputs (Level 3) | Gas Utility | Operating Segments | Gasoline and heating oil contracts
ASSETS
Derivative asset before effects of netting	0	0
Significant Unobservable Inputs (Level 3) | Gas Utility | Operating Segments | NYMEX/ICE natural gas contracts
ASSETS
Derivative asset before effects of netting		0
LIABILITIES
Derivative liability before effects of netting	0	0	0
Significant Unobservable Inputs (Level 3) | Gas Marketing | Operating Segments | NYMEX/ICE natural gas contracts
ASSETS
Derivative asset before effects of netting	0	0	0
LIABILITIES
Derivative liability before effects of netting	0	0	0
Significant Unobservable Inputs (Level 3) | Gas Marketing | Operating Segments | Natural gas commodity contracts
ASSETS
Derivative asset before effects of netting	0	0.4	0
LIABILITIES
Derivative liability before effects of netting	$ 0	$ 0	$ 1.5

Pension Plans and Other Postr_3

Pension Plans and Other Postretirement Benefits - Schedule of Net Periodic Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Pension Plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost – benefits earned during the period	$ 5.6	$ 5.5
Interest cost on projected benefit obligation	5.2	5.9
Expected return on plan assets	(8)	(9.2)
Amortization of prior service cost (credit)	(0.8)	(0.6)
Amortization of actuarial (gain) loss	4	3.7
Subtotal	6	5.3
Regulatory adjustment	9.6	9.6
Net pension cost	15.6	14.9
Other Postretirement Plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost – benefits earned during the period	1.8	1.4
Interest cost on projected benefit obligation	1.4	1.6
Expected return on plan assets	(4)	(4.1)
Amortization of prior service cost (credit)	0.3	(0.2)
Amortization of actuarial (gain) loss	(0.4)	(0.5)
Subtotal	(0.9)	(1.8)
Regulatory adjustment	3.4	4
Net pension cost	2.5	2.2
Spire Missouri | Pension Plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost – benefits earned during the period	3.9	3.8
Interest cost on projected benefit obligation	3.5	4.2
Expected return on plan assets	(5.6)	(6.6)
Amortization of prior service cost (credit)	(0.2)
Amortization of actuarial (gain) loss	2.9	2.9
Subtotal	4.5	4.3
Regulatory adjustment	7.6	7.7
Net pension cost	12.1	12
Spire Missouri | Other Postretirement Plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost – benefits earned during the period	1.6	1.3
Interest cost on projected benefit obligation	1.1	1.2
Expected return on plan assets	(2.7)	(2.8)
Amortization of prior service cost (credit)	0.2	(0.1)
Amortization of actuarial (gain) loss	(0.4)	(0.5)
Subtotal	(0.2)	(0.9)
Regulatory adjustment	3.8	4.4
Net pension cost	3.6	3.5
Spire Alabama | Pension Plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost – benefits earned during the period	1.5	1.5
Interest cost on projected benefit obligation	1.2	1.2
Expected return on plan assets	(1.6)	(1.7)
Amortization of prior service cost (credit)	(0.6)	(0.6)
Amortization of actuarial (gain) loss	1.1	0.8
Subtotal	1.6	1.2
Regulatory adjustment	1.8	1.7
Net pension cost	3.4	2.9
Spire Alabama | Other Postretirement Plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost – benefits earned during the period	0.2	0.1
Interest cost on projected benefit obligation	0.3	0.3
Expected return on plan assets	(1.2)	(1.2)
Amortization of prior service cost (credit)	0.1	(0.1)
Subtotal	(0.6)	(0.9)
Regulatory adjustment	(0.4)	(0.4)
Net pension cost	$ (1)	$ (1.3)

Pension Plans and Other Postr_4

Pension Plans and Other Postretirement Benefits - Additional Information (Details)	3 Months Ended
	Dec. 31, 2020USD ($)plan	Dec. 31, 2019plan
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Medical insurance available until age is reached after early retirement	65 years
Other Postretirement Benefits Plan
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	$ 2,200,000
Other Postretirement Benefits Plan | Spire Missouri
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Number Of Plans | plan	0	0
Anticipated contributions to pension plans for qualified trust	$ 21,800,000
Other Postretirement Benefits Plan | Spire Missouri | Qualified Plan
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	20,200,000
Other Postretirement Benefits Plan | Spire Missouri | Nonqualified Plan
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	$ 0
Other Postretirement Benefits Plan | Spire Alabama
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Number Of Plans | plan	0	0
Anticipated contributions to pension plans for qualified trust	$ 8,900,000
Other Postretirement Benefits Plan | Spire Missouri
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	0
Anticipated contributions to pension plans for qualified trust	0
Other Postretirement Benefits Plan | Spire Alabama
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	0
Anticipated contributions to pension plans for qualified trust	$ 0

Information by Operating Segm_3

Information by Operating Segment - Additional Information (Details) - 3 months ended Dec. 31, 2020	reporting_unit	operating-segment
Segment Reporting [Abstract]
Number of reportable segments	2	2

Information by Operating Segm_4

Information by Operating Segment - Schedule of Operating Segment Information (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2020
Operating Segment Information [Abstract]
Operating Revenues	$ 512.6	$ 566.9
Operating Expenses:
Natural gas	181.2	261.9
Operation and maintenance	111.6	116.6
Depreciation and amortization	50.8	47.5
Taxes, other than income taxes	36.1	38.6
Total Operating Expenses	379.7	464.6
Net Economic Earnings (Loss)	76.9	71.8
Operating Income	132.9	102.3
Total Assets	8,515.6	7,961	$ 8,241.2
Eliminations
Operating Segment Information [Abstract]
Operating Revenues	(27.1)	(7.2)
Operating Expenses:
Natural gas	(23.8)	(4.2)
Operation and maintenance	(3.3)	(3)
Depreciation and amortization	0	0
Taxes, other than income taxes	0	0
Total Operating Expenses	(27.1)	(7.2)
Net Economic Earnings (Loss)	0	0
Operating Income	0	0
Total Assets	(1,083.8)	(1,038.2)	(1,101.2)
Gas Utility
Operating Segment Information [Abstract]
Operating Revenues	497.2	530.6
Gas Utility | Eliminations
Operating Segment Information [Abstract]
Operating Revenues	1	0.1
Gas Utility | Operating Segments
Operating Segment Information [Abstract]
Operating Revenues	498.2	530.7
Operating Expenses:
Natural gas	204.3	241.5
Operation and maintenance	103	108.6
Depreciation and amortization	48.6	46.4
Taxes, other than income taxes	35.5	37.9
Total Operating Expenses	391.4	434.4
Net Economic Earnings (Loss)	76.4	69.1
Operating Income	106.8	96.3
Total Assets	6,932.3	6,306	6,716.2
Gas Marketing
Operating Segment Information [Abstract]
Operating Revenues	10.7	32.3
Gas Marketing | Eliminations
Operating Segment Information [Abstract]
Operating Revenues	14.1	0
Gas Marketing | Operating Segments
Operating Segment Information [Abstract]
Operating Revenues	24.8	32.3
Operating Expenses:
Natural gas	0.7	24.5
Operation and maintenance	3.3	3.1
Depreciation and amortization	0.3	0
Taxes, other than income taxes	0.2	0.3
Total Operating Expenses	4.5	27.9
Net Economic Earnings (Loss)	3.3	6.1
Operating Income	20.3	4.4
Total Assets	204.8	242.7	182.7
Corporate, Non-Segment
Operating Segment Information [Abstract]
Operating Revenues	4.7	4
Corporate, Non-Segment | Eliminations
Operating Segment Information [Abstract]
Operating Revenues	12	7.1
Corporate, Non-Segment | Operating Segments
Operating Segment Information [Abstract]
Operating Revenues	16.7	11.1
Operating Expenses:
Natural gas	0	0.1
Operation and maintenance	8.6	7.9
Depreciation and amortization	1.9	1.1
Taxes, other than income taxes	0.4	0.4
Total Operating Expenses	10.9	9.5
Net Economic Earnings (Loss)	(2.8)	(3.4)
Operating Income	5.8	1.6
Total Assets	$ 2,462.3	$ 2,450.5	$ 2,443.5

Information by Operating Segm_5

Information by Operating Segment - Reconciliation of Consolidated Net Economic Earnings to Consolidated Net Income (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting [Abstract]
Net Income	$ 88.9	$ 67
Provision for ISRS rulings	0	2.6
Fair value and timing adjustments	(16)	3.7
Income tax effect of adjustments	4	(1.5)
Net Economic Earnings	$ 76.9	$ 71.8

Commitments and Contingencies -

Commitments and Contingencies - Additional Information - Commitments (Details) $ in Millions	3 Months Ended
	Dec. 31, 2020USD ($)
Long-term Purchase Commitment [Line Items]
Minimum total payments required for natural gas contracts	$ 1,739.4
Spire Missouri
Long-term Purchase Commitment [Line Items]
Minimum total payments required for natural gas contracts	1,319.4
Spire Alabama
Long-term Purchase Commitment [Line Items]
Minimum total payments required for natural gas contracts	$ 310.3

Commitments and Contingencies_2

Commitments and Contingencies - Additional Information - Contingencies (Details) - site	Dec. 31, 2020	Sep. 30, 2013
Spire Missouri East
Site Contingency [Line Items]
Number of former manufactured gas plant (MGP) sites in Missouri	3
Number of sites enrolled in Brownfields/Voluntary clean up program	2
Spire Missouri East | Previous Ownership
Site Contingency [Line Items]
Number of former manufactured gas plant (MGP)		19
Spire Missouri West | Previous Ownership
Site Contingency [Line Items]
Number of former manufactured gas plant (MGP)	7
Spire Alabama
Site Contingency [Line Items]
Number of former manufactured gas plant (MGP)	9
Number of former manufactured gas distribution	5
Spire Alabama | Current Ownership
Site Contingency [Line Items]
Number of former manufactured gas plant (MGP)	4
Number of former manufactured gas distribution	1