Spire Alabama 10-Q 2 May 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Mar. 31, 2018	Apr. 30, 2018
Entity Information [Line Items]
Entity Registrant Name	SPIRE INC
Entity Central Index Key	1,126,956
Current Fiscal Year End Date	--09-30
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		48,359,068
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Spire Missouri
Entity Information [Line Items]
Entity Registrant Name	SPIRE MISSOURI INC
Entity Central Index Key	57,183
Current Fiscal Year End Date	--09-30
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		24,577
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Spire Alabama
Entity Information [Line Items]
Entity Registrant Name	SPIRE ALABAMA INC
Entity Central Index Key	3,146
Current Fiscal Year End Date	--09-30
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		1,972,052
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Operating Revenues:
Gas Utility	$ 790.6	$ 641.1	$ 1,332.5	$ 1,113.4
Gas Marketing and other	22.8	22.3	42.7	45.1
Total Operating Revenues	813.4	663.4	1,375.2	1,158.5
Gas Utility
Natural and propane gas	383.7	254.3	624.5	448.1
Operation and maintenance	143.6	98.4	241.5	197.8
Depreciation and amortization	41.1	37.9	81.4	75.6
Taxes, other than income taxes	58	48.3	94.7	81.7
Total Gas Utility Operating Expenses	626.4	438.9	1,042.1	803.2
Gas Marketing and other	45.2	44.1	86.2	85.8
Total Operating Expenses	671.6	483	1,128.3	889
Operating Income	141.8	180.4	246.9	269.5
Other Income - Net	0.7	3.6	2.9	4.1
Interest Charges:
Interest on long-term debt	21	19.2	41.7	38.3
Other interest charges	4.4	3.5	8.1	6.5
Total Interest Charges	25.4	22.7	49.8	44.8
Income Before Income Taxes	117.1	161.3	200	228.8
Income Tax Expense (Benefit)	18.9	53.3	(14.2)	75.6
Net Income	$ 98.2	$ 108	$ 214.2	$ 153.2
Weighted Average Number of Shares Outstanding:
Basic (in shares)	48.2	45.6	48.2	45.6
Diluted (in shares)	48.4	45.7	48.4	45.7
Basic Earnings Per Share (in dollars per share)	$ 2.03	$ 2.36	$ 4.43	$ 3.35
Diluted Earnings Per Share (in dollars per share)	2.03	2.36	4.42	3.34
Dividends Declared Per Share (in dollars per share)	$ 0.5625	$ 0.525	$ 1.125	$ 1.05
Spire Missouri
Operating Revenues:
Gas Utility	$ 533.2	$ 447.2	$ 925.5	$ 810.8
Total Operating Revenues	533.2	447.2	925.5	810.8
Gas Utility
Natural and propane gas	311.2	241.2	517.4	432.5
Operation and maintenance	103.5	57.5	163.8	118
Depreciation and amortization	25.2	23	50	45.7
Taxes, other than income taxes	41.2	35.3	67.4	59.9
Total Operating Expenses	481.1	357	798.6	656.1
Operating Income	52.1	90.2	126.9	154.7
Other Income - Net	(0.4)	1.9	0.8	2
Interest Charges:
Interest on long-term debt	9.8	8.2	19.7	16.5
Other interest charges	2.1	1.5	3.8	2.9
Total Interest Charges	11.9	9.7	23.5	19.4
Income Before Income Taxes	39.8	82.4	104.2	137.3
Income Tax Expense (Benefit)	1.4	25.4	(23.6)	42.3
Net Income	38.4	57	127.8	95
Spire Alabama
Operating Revenues:
Gas Utility	218.3	158.8	339.1	245.5
Total Operating Revenues	218.3	158.8	339.1	245.5
Gas Utility
Natural and propane gas	78.5	25.8	127.5	42.6
Operation and maintenance	34.1	31.5	65.9	62.7
Depreciation and amortization	13.1	12.3	25.9	24.6
Taxes, other than income taxes	14.4	10.3	22.6	16.9
Total Operating Expenses	140.1	79.9	241.9	146.8
Operating Income	78.2	78.9	97.2	98.7
Other Income - Net	0.5	1.1	0.9	1.5
Interest Charges:
Interest on long-term debt	3.5	2.8	6.4	5.6
Other interest charges	0.9	0.7	2	1.5
Total Interest Charges	4.4	3.5	8.4	7.1
Income Before Income Taxes	74.3	76.5	89.7	93.1
Income Tax Expense (Benefit)	18.7	28.9	83.7	35.2
Net Income	$ 55.6	$ 47.6	$ 6	$ 57.9

CONDENSED CONSOLIDATED STATEME3

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Net Income	$ 98.2	$ 108	$ 214.2	$ 153.2
Cash flow hedging derivative instruments:
Net hedging gains arising during the period	1.8	1	1.9	12.5
Reclassification adjustment for (gains) losses included in net income	(0.4)	(0.1)	(0.8)	0.1
Net unrealized gains on cash flow hedging derivative instruments	1.4	0.9	1.1	12.6
Net gains on defined benefit pension and other postretirement plans	0	0	0.1	0.1
Net unrealized losses on available for sale securities	0	0	(0.1)	(0.1)
Other Comprehensive Income, Before Tax	1.4	0.9	1.1	12.6
Income Tax Expense Related to Items of Other Comprehensive Income	0.3	0.4	0.2	4.7
Other Comprehensive Income, Net of Tax	1.1	0.5	0.9	7.9
Comprehensive Income	99.3	108.5	215.1	161.1
Spire Missouri
Net Income	38.4	57	127.8	95
Cash flow hedging derivative instruments:
Other Comprehensive Income, Net of Tax	(0.1)	(0.2)	(0.1)	0
Comprehensive Income	$ 38.3	$ 56.8	$ 127.7	$ 95

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Millions	Mar. 31, 2018	Sep. 30, 2017	Mar. 31, 2017
ASSETS
Utility Plant	$ 5,403.4	$ 5,278.4	$ 4,978.8
Less: Accumulated depreciation and amortization	1,645	1,613.2	1,585.9
Net Utility Plant	3,758.4	3,665.2	3,392.9
Non-utility Property (net of accumulated depreciation and amortization of $9.1, $8.6 and $7.8 at March 31, 2018, September 30, 2017, and March 31, 2017, respectively)	116.9	52	26.6
Goodwill	1,171.6	1,171.6	1,163.9
Other Investments	66.4	64.2	63.2
Total Other Property and Investments	1,354.9	1,287.8	1,253.7
Current Assets:
Cash and cash equivalents	17.8	7.4	19.6
Accounts receivable:
Utility	302.4	140.5	238.5
Other	111.3	149.2	127.9
Allowance for doubtful accounts	(25.7)	(18.3)	(20.8)
Delayed customer billings	45.6	3.4	11.6
Inventories:
Natural gas	94.3	194.9	117.6
Propane gas	12	12	12
Materials and supplies	22.2	18.9	16.8
Natural gas receivable	3	1.9	7.8
Derivative instrument assets	7.3	5.9	8.2
Unamortized purchased gas adjustments	32.6	102.6	61
Other regulatory assets	65.1	72.9	64.8
Prepayments and other	30.4	34.2	19.3
Total Current Assets	718.3	725.5	684.3
Deferred Charges:
Regulatory assets	673.6	791.1	827.7
Other	81.6	77.1	98.1
Total Deferred Charges	755.2	868.2	925.8
Total Assets	6,586.8	6,546.7	6,256.7
Capitalization:
Common stock (par value $1.00 per share; 70.0 million shares authorized; 48.4 million, 48.3 million and 45.7 million shares issued and outstanding at March 31, 2018, September 30, 2017 and March 31, 2017, respectively)	48.4	48.3	45.7
Paid-in capital	1,327.3	1,325.6	1,177.7
Retained earnings	773.7	614.2	655.9
Accumulated other comprehensive income	4.1	3.2	3.7
Total Equity	2,153.5	1,991.3	1,883
Redeemable noncontrolling interest	6.5	0	0
Long-term debt (less current portion)	2,073.9	1,995	1,925.3
Total Capitalization	4,233.9	3,986.3	3,808.3
Current Liabilities:
Current portion of long-term debt	105.5	100	0
Notes payable	391.7	477.3	567.4
Accounts payable	194.8	257.1	218.6
Advance customer billings	8.1	32	14.5
Wages and compensation accrued	30	38.7	29
Dividends payable	28.3	26.6	24.9
Customer deposits	36.1	34.9	35.7
Interest accrued	15.8	14.6	15.3
Taxes accrued	49.1	61	46.7
Unamortized purchased gas adjustments	1.5	1	1.6
Other regulatory liabilities	20.7	21.6	29.7
Other	46.4	33.1	31.9
Total Current Liabilities	928	1,097.9	1,015.3
Deferred Credits and Other Liabilities:
Deferred income taxes	465.6	707.5	690.6
Pension and postretirement benefit costs	233.4	237.4	308.1
Asset retirement obligations	302.8	296.6	212.4
Regulatory liabilities	353.1	157.2	144.1
Other	70	63.8	77.9
Total Deferred Credits and Other Liabilities	1,424.9	1,462.5	1,433.1
Commitments and Contingencies (Note 10)
Total Capitalization and Liabilities	6,586.8	6,546.7	6,256.7
Spire Missouri
ASSETS
Utility Plant	3,163.8	3,091.8	2,855
Less: Accumulated depreciation and amortization	687.2	681.6	659.6
Net Utility Plant	2,476.6	2,410.2	2,195.4
Goodwill	210.2	210.2	210.2
Other Investments	59	59.4	58.3
Total Other Property and Investments	269.2	269.6	268.5
Current Assets:
Cash and cash equivalents	10.2	2.5	3.7
Accounts receivable:
Utility	222.4	101.7	166.4
Associated companies	1.3	3.3	22.7
Other	26	15	12
Allowance for doubtful accounts	(20.7)	(14.1)	(16.5)
Delayed customer billings	45.6	3.4	11.6
Inventories:
Natural gas	60	138.2	75.8
Propane gas	12	12	12
Materials and supplies	13.1	11.3	9.9
Derivative instrument assets	0	0.1	2.9
Unamortized purchased gas adjustments	13.5	57.4	17.1
Other regulatory assets	38.2	38.2	38.2
Prepayments and other	10.7	19.6	10.5
Total Current Assets	432.3	388.6	366.3
Deferred Charges:
Regulatory assets	446.6	557.8	569.4
Other	9	5.3	2.6
Total Deferred Charges	455.6	563.1	572
Total Assets	3,633.7	3,631.5	3,402.2
Capitalization:
Paid-in capital and common stock	758.4	756.2	753.9
Retained earnings	517.3	416.5	398.6
Accumulated other comprehensive income	(1.8)	(1.7)	(1.8)
Total Equity	1,273.9	1,171	1,150.7
Long-term debt (less current portion)	874	873.9	804.3
Total Capitalization	2,147.9	2,044.9	1,955
Current Liabilities:
Current portion of long-term debt	100	100	0
Notes payable – associated companies	175.8	203	282.2
Accounts payable	69.2	89.9	57.8
Accounts payable – associated companies	3.6	5.4	5.1
Advance customer billings	0	13.3	0.2
Wages and compensation accrued	23.4	29.6	21.8
Dividends payable	13.5	0	0
Customer deposits	13.2	13.3	13.1
Interest accrued	8.2	8	7.9
Taxes accrued	25.2	34.1	23.8
Other regulatory liabilities	2.7	2.7	2.7
Other	19.4	8.5	8.7
Total Current Liabilities	454.2	507.8	423.3
Deferred Credits and Other Liabilities:
Deferred income taxes	388.6	623.8	607.7
Pension and postretirement benefit costs	161.9	173	213.5
Asset retirement obligations	161.9	158.6	77
Regulatory liabilities	272.5	81.2	84.5
Other	46.7	42.2	41.2
Total Deferred Credits and Other Liabilities	1,031.6	1,078.8	1,023.9
Commitments and Contingencies (Note 10)
Total Capitalization and Liabilities	3,633.7	3,631.5	3,402.2
Spire Alabama
ASSETS
Utility Plant	1,885.4	1,838	1,776.1
Less: Accumulated depreciation and amortization	803.9	782	779.1
Net Utility Plant	1,081.5	1,056	997
Current Assets:
Cash and cash equivalents	0	0.1	0
Accounts receivable:
Utility	64.1	32	62
Associated companies	0.1	0	0.4
Other	6.4	6.2	5.7
Allowance for doubtful accounts	(2.7)	(2.6)	(2.3)
Inventories:
Natural gas	26.2	33.9	26.5
Materials and supplies	7.8	6.5	5.8
Unamortized purchased gas adjustments	19	45.2	43.9
Other regulatory assets	13.1	19.4	11.2
Prepayments and other	5.6	6.7	4.1
Total Current Assets	139.6	147.4	157.3
Deferred Charges:
Regulatory assets	198.9	197	229.3
Deferred income taxes	100.3	185.6	186.2
Other	57.9	57	62
Total Deferred Charges	357.1	439.6	477.5
Total Assets	1,578.2	1,643	1,631.8
Capitalization:
Paid-in capital and common stock	390.9	420.9	420.9
Retained earnings	437.5	446.5	462.8
Total Equity	828.4	867.4	883.7
Long-term debt (less current portion)	322.5	247.8	247.7
Total Capitalization	1,150.9	1,115.2	1,131.4
Current Liabilities:
Notes payable – associated companies	82.3	169.9	109.3
Accounts payable	42.9	44.4	42.8
Accounts payable – associated companies	1.5	1.6	1.5
Advance customer billings	7.9	18.6	14.3
Wages and compensation accrued	5.3	7.4	5.2
Customer deposits	19	17.9	18.9
Interest accrued	4.1	3.3	3.4
Taxes accrued	21.9	23.4	16.9
Other regulatory liabilities	10.8	12	25.1
Other	2.4	2.9	4.8
Total Current Liabilities	198.1	301.4	242.2
Deferred Credits and Other Liabilities:
Pension and postretirement benefit costs	55.3	50.2	76.6
Asset retirement obligations	131.1	128.4	124.1
Regulatory liabilities	35	39.6	35.9
Other	7.8	8.2	21.6
Total Deferred Credits and Other Liabilities	229.2	226.4	258.2
Total Capitalization and Liabilities	$ 1,578.2	$ 1,643	$ 1,631.8

CONDENSED CONSOLIDATED BALANCE5

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2018	Sep. 30, 2017	Mar. 31, 2017
Assets
Non-utility property, accumulated depreciation and amortization	$ 9.1	$ 8.6	$ 7.8
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)	48,400,000	48,300,000	45,700,000
Common stock, outstanding (in shares)	48,400,000	48,300,000	45,700,000
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

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF COMMON SHAREHOLDER'S EQUITY (UNAUDITED) - USD ($) $ in Millions	Total	Common Stock Outstanding	Paid-in Capital	Retained Earnings	AOCI	Spire Missouri	Spire MissouriCommon Stock Outstanding	Spire MissouriPaid-in Capital	Spire MissouriRetained Earnings	Spire MissouriAOCI	Spire Alabama	Spire AlabamaCommon Stock Outstanding	Spire AlabamaPaid-in Capital	Spire AlabamaRetained Earnings
Beginning Balance, (in shares) at Sep. 30, 2016		45,650,642					24,577					1,972,052
Beginning Balance at Sep. 30, 2016	$ 1,768.2	$ 45.6	$ 1,175.9	$ 550.9	$ (4.2)	$ 1,068.5	$ 0.1	$ 751.9	$ 318.3	$ (1.8)	$ 867.3	$ 0	$ 451.9	$ 415.4
Stockholders' Equity Rollforward
Net income	153.2			153.2		95			95		57.9			57.9
Dividend reinvestment plan (in shares)		11,820
Dividend reinvestment plan	0.8		0.8
Stock-based compensation costs	3.3		3.3			1.9		1.9
Stock issued under stock-based compensation plans (in shares)		122,094
Stock issued under stock-based compensation plans	0	$ 0.1	(0.1)
Employee's tax withholding for stock-based compensation (in shares)		(34,589)
Employee’s tax withholding for stock-based compensation	(2.2)		(2.2)
Return of capital to Spire											(31)		(31)
Dividends declared	(48.2)			(48.2)		(14.7)			(14.7)		(10.5)			(10.5)
Other comprehensive income (loss), net of tax	7.9				7.9	0
Ending Balance, (in shares) at Mar. 31, 2017		45,749,967					24,577					1,972,052
Ending Balance at Mar. 31, 2017	1,883	$ 45.7	1,177.7	655.9	3.7	1,150.7	$ 0.1	753.8	398.6	(1.8)	883.7	$ 0	420.9	462.8
Beginning Balance, (in shares) at Sep. 30, 2017		48,263,243					24,577					1,972,052
Beginning Balance at Sep. 30, 2017	1,991.3	$ 48.3	1,325.6	614.2	3.2	1,171	$ 0.1	756.1	416.5	(1.7)	867.4	$ 0	420.9	446.5
Stockholders' Equity Rollforward
Net income	214.2			214.2		127.8			127.8		6			6
Dividend reinvestment plan (in shares)		11,003
Dividend reinvestment plan	0.8		0.8
Stock-based compensation costs	3.8		3.8			2.2		2.2
Stock issued under stock-based compensation plans (in shares)		114,114
Stock issued under stock-based compensation plans	0	$ 0.1	(0.1)
Employee's tax withholding for stock-based compensation (in shares)		(33,581)
Employee’s tax withholding for stock-based compensation	(2.8)		(2.8)
Return of capital to Spire											(30)		(30)
Dividends declared	(54.7)			(54.7)		(27)			(27)		(15)			(15)
Other comprehensive income (loss), net of tax	0.9				0.9	(0.1)				(0.1)
Ending Balance, (in shares) at Mar. 31, 2018		48,354,779					24,577					1,972,052
Ending Balance at Mar. 31, 2018	$ 2,153.5	$ 48.4	$ 1,327.3	$ 773.7	$ 4.1	$ 1,273.9	$ 0.1	$ 758.3	$ 517.3	$ (1.8)	$ 828.4	$ 0	$ 390.9	$ 437.5

CONDENSED CONSOLIDATED STATEME7

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating Activities:
Net Income	$ 214.2	$ 153.2
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	81.9	75.8
Deferred income taxes and investment tax credits	(15.2)	75.4
Changes in assets and liabilities:
Accounts receivable	(122.8)	(123)
Unamortized purchased gas adjustments	128.8	0.2
Accounts payable	(50)	28.3
Delayed/advance customer billings – net	(66)	(65.7)
Taxes accrued	(11.9)	(13.8)
Inventories	97.3	55.9
Other assets and liabilities	11.5	36.7
Other	41.8	3.1
Net cash provided by operating activities	309.6	226.1
Investing Activities:
Capital expenditures	(215.8)	(187.3)
Business acquisitions	(17.1)	3.8
Other	(0.4)	0.6
Net cash used in investing activities	(233.3)	(182.9)
Financing Activities:
Issuance of long-term debt	75	250
Repayment of long-term debt	0	(393.8)
(Repayment) issuance of short-term debt – net	(85.6)	168.7
Issuance of common stock	0.8	0.1
Dividends paid	(53)	(46.8)
Other	(3.1)	(7)
Net cash (used in) provided by financing activities	(65.9)	(28.8)
Net Increase in Cash and Cash Equivalents	10.4	14.4
Cash and Cash Equivalents at Beginning of Period	7.4	5.2
Cash and Cash Equivalents at End of Period	17.8	19.6
Supplemental disclosure of cash paid for:
Interest, net of amounts capitalized	(47.2)	(41.8)
Income taxes	(0.6)	(0.9)
Spire Missouri
Operating Activities:
Net Income	127.8	95
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	50	45.7
Deferred income taxes and investment tax credits	(23.6)	42.3
Changes in assets and liabilities:
Accounts receivable	(123.2)	(99.2)
Unamortized purchased gas adjustments	102.2	37.5
Accounts payable	(10.8)	(4.5)
Delayed/advance customer billings – net	(55.5)	(58.9)
Taxes accrued	(8.9)	(5.3)
Inventories	76.4	50.8
Other assets and liabilities	2.8	10.3
Other	40.9	0.8
Net cash provided by operating activities	178.1	114.5
Investing Activities:
Capital expenditures	(129.6)	(122.2)
Other	(0.1)	0.5
Net cash used in investing activities	(129.7)	(121.7)
Financing Activities:
(Repayment) issuance of short-term debt – net	0	(243.7)
(Repayments to) borrowings from Spire – net	(27.2)	282.2
Dividends paid	(13.5)	(28.7)
Other	0	(1)
Net cash (used in) provided by financing activities	(40.7)	8.8
Net Increase in Cash and Cash Equivalents	7.7	1.6
Cash and Cash Equivalents at Beginning of Period	2.5	2.1
Cash and Cash Equivalents at End of Period	10.2	3.7
Supplemental disclosure of cash paid for:
Interest, net of amounts capitalized	(22.8)	(19)
Income taxes	0	0
Spire Alabama
Operating Activities:
Net Income	6	57.9
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	25.9	24.6
Deferred income taxes and investment tax credits	83.7	35.2
Changes in assets and liabilities:
Accounts receivable	(38.6)	(25.8)
Unamortized purchased gas adjustments	26.2	(38.3)
Accounts payable	0.3	10.3
Delayed/advance customer billings – net	(10.6)	(6.8)
Taxes accrued	(1.5)	(4.7)
Inventories	6.4	8.2
Other assets and liabilities	12.4	2
Other	(0.2)	0.3
Net cash provided by operating activities	110	62.9
Investing Activities:
Capital expenditures	(51.8)	(48.3)
Other	(0.4)	0
Net cash used in investing activities	(52.2)	(48.3)
Financing Activities:
Issuance of long-term debt	75	0
(Repayment) issuance of short-term debt – net	0	(82)
(Repayments to) borrowings from Spire – net	(87.6)	109.3
Return of capital to Spire	(30)	(31)
Dividends paid	(15)	(10.5)
Other	(0.3)	(0.4)
Net cash (used in) provided by financing activities	(57.9)	(14.6)
Net Increase in Cash and Cash Equivalents	(0.1)	0
Cash and Cash Equivalents at Beginning of Period	0.1	0
Cash and Cash Equivalents at End of Period	0	0
Supplemental disclosure of cash paid for:
Interest, net of amounts capitalized	(7)	(6.3)
Income taxes	$ 0	$ 0

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	6 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	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), as well as Spire Missouri Inc. (Spire Missouri or the Missouri Utilities) and Spire Alabama Inc. (Spire Alabama). Spire Missouri and Spire Alabama are wholly owned subsidiaries of the Company. 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 of the disclosures required for complete financial statements. In the opinion of management, the accompanying unaudited financial statements include all adjustments (consisting of only normal recurring 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, 2017 . 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. At the end of December 2017, a subsidiary of the Company acquired an 80% voting interest in Ryckman Creek Resources, LLC, which owns and operates a natural gas storage facility in Wyoming. The transaction was valued at $24.8 , subject to customary post-closing adjustments, and was completed with $16.0 of cash and a $10.0 non-interest-bearing promissory note valued at $8.8 . A tentative purchase price allocation to the assets acquired and liabilities assumed is reflected in the Company’s consolidated balance sheet as of March 31, 2018. Management is evaluating certain fair value accounting impacts, and any related adjustments will be recorded later this year. Results of operations are included in the Company’s consolidated financial statements since the acquisition date. The redeemable noncontrolling interest, which was shown in permanent equity at the end of the first quarter, is shown as temporary equity on the balance sheet. NATURE OF OPERATIONS – Spire Inc. (NYSE: SR), headquartered in St. Louis, Missouri, is a public utility holding company. The Company 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 generation. The Gas Utility segment is comprised of the operations of: the Missouri Utilities, serving St. Louis and eastern Missouri (Spire Missouri East) and Kansas City and western Missouri (Spire Missouri West); 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 non-utility business, Spire Marketing Inc. (Spire Marketing), which provides non-regulated natural gas services. 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 of the Company’s earnings are derived from its Gas Utility segment. Due to the seasonal nature of the Utilities’ business, 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. REVENUE RECOGNITION – The Utilities read meters and bill customers on monthly cycles. The Missouri Utilities, Spire Gulf and Spire Mississippi record their gas utility revenues from gas sales and transportation services on an accrual basis that includes estimated amounts for gas delivered but not yet billed. The accruals for unbilled revenues are reversed in the subsequent accounting period when meters are actually read and customers are billed. The amounts of accrued unbilled revenues for Spire Missouri at March 31, 2018 , September 30, 2017 , and March 31, 2017 , were $85.2 , $30.1 , and $66.7 , respectively. Spire Alabama records natural gas distribution revenues in accordance with the tariff established by the Alabama Public Service Commission (APSC). Unbilled revenue is accrued in an amount equal to the related gas cost, as profit margin is not considered earned until billed. The amounts of accrued unbilled revenues for Spire Alabama at March 31, 2018 , September 30, 2017 , and March 31, 2017 were $5.3 , $1.9 , and $13.5 , respectively. Spire’s other subsidiaries, including Spire Marketing, record revenues when earned, either when the product is delivered or when services are performed. In the course of its business, Spire Marketing enters 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 using a gross presentation. 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. GROSS RECEIPTS AND SALES TAXES – Gross receipts taxes associated with the Company’s natural gas utility services are imposed on the Utilities and billed to their customers. The revenue and expense amounts are recorded gross in the “Operating Revenues” and “Taxes, other than income taxes” lines, respectively, in the statements of income. The following table presents gross receipts and sales taxes recorded as revenues: Three Months Ended March 31, Six Months Ended March 31, 2018 2017 2018 2017 Spire $ 43.6 $ 34.3 $ 66.7 $ 53.7 Spire Missouri 30.6 25.5 46.8 39.6 Spire Alabama 11.6 7.7 17.2 11.9 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 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 3 , Regulatory Matters. TRANSACTIONS WITH AFFILIATES – Transactions between affiliates of the Company have been eliminated from the consolidated 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 included: Three Months Ended March 31, Six Months Ended March 31, 2018 2017 2018 2017 Purchases of natural gas from Spire Marketing $ 19.3 $ 21.0 $ 41.6 $ 41.5 Sales of natural gas to Spire Marketing 0.2 2.7 0.3 6.3 Transportation services received from Spire NGL Inc. 0.2 0.2 0.5 0.5 ACCRUED CAPITAL EXPENDITURES – Accrued capital expenditures, shown in the following table, are excluded from capital expenditures in the statements of cash flows until paid. March 31, September 30, March 31, 2018 2017 2017 Spire $ 29.1 $ 41.0 $ 9.2 Spire Missouri 17.9 28.9 3.3 Spire Alabama 7.0 9.4 5.3 NEW ACCOUNTING PRONOUNCEMENTS – In May 2014, the FASB issued Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers . Under the new standard, an entity will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In doing so, companies may need to use more judgment and make more estimates than under current guidance. ASU No. 2014-09 also requires disclosures that will enable users of financial statements to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. Existing alternative revenue program guidance, though excluded by the FASB in updating specific guidance associated with revenue from contracts with customers, was relocated without substantial modification to accounting guidance for rate-regulated entities. It will require separate presentation of such revenues in the statement of income. Entities have the option of using either a full retrospective or modified retrospective approach to adopting this guidance. In August 2015, the FASB issued ASU No. 2015-14, which made the guidance in ASU No. 2014-09 effective for fiscal years beginning after December 15, 2017, and interim periods within those years. In 2016 and 2017, the FASB issued related ASU Nos. 2016-08, 2016-10, 2016-11, 2016-12, 2016-20, and 2017-14, which further modified the standards for accounting for revenue. The Company, Spire Missouri and Spire Alabama have nearly completed their evaluation of their sources of revenue and related contracts, plan to adopt the new guidance in the first quarter of fiscal 2019 using the modified retrospective approach, and expect no material effect on their financial position, results of operations, or cash flows. In February 2016, the FASB issued ASU No. 2016-02, Leases . The new standard requires lessees to recognize a right-of-use asset and lease liability for almost all lease contracts based on the present value of lease payments. There is an exemption for short-term leases. The ASU provides new guidelines for identifying and classifying a lease, and classification affects the pattern and income statement line item for the related expense. This update will be applied using a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. ASU No. 2018-01, issued in January 2018, clarifies the related transition and accounting for existing and new or modified land easements. The ASUs are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company, Spire Missouri and Spire Alabama are currently assessing the timing and impacts of adopting these standards, which must be adopted by the first quarter of fiscal 2020. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments . The standard introduces new guidance for the accounting for credit losses on instruments within its scope, including trade receivables. It is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, and may be adopted a year earlier. The new guidance will be initially applied through a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. The Company, Spire Missouri and Spire Alabama are currently assessing the timing and impacts of adopting this standard, which must be adopted by the first quarter of fiscal 2021. In March 2017, the FASB issued ASU No. 2017-07, Compensation – Retirement Benefits: Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost . The amended guidance requires that the service cost component of pension and postretirement benefit costs be presented within the same line item in the income statement as other compensation costs (except for the amount being capitalized), while other components are to be presented outside the subtotal of operating income and are no longer eligible for capitalization. The ASU is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. The amended guidance will be applied retrospectively for income statement presentation and prospectively for capitalization. The Company, Spire Missouri and Spire Alabama are currently assessing the regulatory and other impacts of adopting this standard, which must be adopted by the first quarter of fiscal 2019. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities . The amendments in this ASU more closely align the results of hedge accounting with risk management activities through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results in the financial statements. They are effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, and early application is permitted. The Company, Spire Missouri and Spire Alabama are currently assessing the effects of this new guidance, as well as the timing of adoption.

EARNINGS PER COMMON SHARE

EARNINGS PER COMMON SHARE	6 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
EARNINGS PER COMMON SHARE	EARNINGS PER COMMON SHARE Spire Three Months Ended March 31, Six Months Ended March 31, 2018 2017 2018 2017 Basic Earnings Per Share: Net Income $ 98.2 $ 108.0 $ 214.2 $ 153.2 Less: Income allocated to participating securities 0.2 0.2 0.5 0.4 Net Income Available to Common Shareholders $ 98.0 $ 107.8 $ 213.7 $ 152.8 Weighted Average Shares Outstanding (in millions) 48.2 45.6 48.2 45.6 Basic Earnings Per Share of Common Stock $ 2.03 $ 2.36 $ 4.43 $ 3.35 Diluted Earnings Per Share: Net Income $ 98.2 $ 108.0 $ 214.2 $ 153.2 Less: Income allocated to participating securities 0.2 0.2 0.5 0.4 Net Income Available to Common Shareholders $ 98.0 $ 107.8 $ 213.7 $ 152.8 Weighted Average Shares Outstanding (in millions) 48.2 45.6 48.2 45.6 Dilutive Effect of Restricted Stock and Restricted Stock Units (in millions)* 0.2 0.1 0.2 0.1 Weighted Average Diluted Shares (in millions) 48.4 45.7 48.4 45.7 Diluted Earnings Per Share of Common Stock $ 2.03 $ 2.36 $ 4.42 $ 3.34 * Calculation excludes certain outstanding 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 0.4 0.5 0.4 0.5

REGULATORY MATTERS

REGULATORY MATTERS	6 Months Ended
	Mar. 31, 2018
Regulated Operations [Abstract]
REGULATORY MATTERS	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 . The following regulatory assets and regulatory liabilities, including purchased gas adjustments, were reflected in the balance sheets of the Company, Spire Missouri and Spire Alabama as of March 31, 2018 , September 30, 2017 , and March 31, 2017 . March 31, September 30, March 31, Spire 2018 2017 2017 Regulatory Assets: Current: Pension and postretirement benefit costs $ 43.0 $ 42.2 $ 41.7 Unamortized purchased gas adjustments 32.6 102.6 61.0 Other 22.1 30.7 23.1 Total Current Regulatory Assets 97.7 175.5 125.8 Noncurrent: Future income taxes due from customers 113.0 170.5 159.7 Pension and postretirement benefit costs 358.2 404.7 461.8 Cost of removal 125.0 123.3 133.9 Unamortized purchased gas adjustments — 9.9 1.1 Energy efficiency 31.3 29.0 27.0 Other 46.1 53.7 44.2 Total Noncurrent Regulatory Assets 673.6 791.1 827.7 Total Regulatory Assets $ 771.3 $ 966.6 $ 953.5 Regulatory Liabilities: Current: Rate Stabilization and Equalization (RSE) adjustment $ — $ 1.4 $ 1.1 Unbilled service margin — — 13.5 Refundable negative salvage 5.3 8.2 8.1 Unamortized purchased gas adjustments 1.5 1.0 1.6 Other 15.4 12.0 7.0 Total Current Regulatory Liabilities 22.2 22.6 31.3 Noncurrent: Deferred taxes due to customers 170.7 — — Pension and postretirement benefit costs 30.8 32.2 27.6 Refundable negative salvage 0.6 4.1 4.9 Accrued cost of removal 71.0 83.8 75.3 Unamortized purchased gas adjustments 50.3 1.9 2.0 Other 29.7 35.2 34.3 Total Noncurrent Regulatory Liabilities 353.1 157.2 144.1 Total Regulatory Liabilities $ 375.3 $ 179.8 $ 175.4 March 31, September 30, March 31, Spire Missouri 2018 2017 2017 Regulatory Assets: Current: Pension and postretirement benefit costs $ 34.9 $ 34.9 $ 34.8 Unamortized purchased gas adjustments 13.5 57.4 17.1 Other 3.3 3.3 3.4 Total Current Regulatory Assets 51.7 95.6 55.3 Noncurrent: Future income taxes due from customers 111.4 170.5 159.7 Pension and postretirement benefit costs 279.0 322.7 358.3 Unamortized purchased gas adjustments — 9.9 1.1 Energy efficiency 31.3 29.0 27.0 Other 24.9 25.7 23.3 Total Noncurrent Regulatory Assets 446.6 557.8 569.4 Total Regulatory Assets $ 498.3 $ 653.4 $ 624.7 Regulatory Liabilities: Current: Other $ 2.7 $ 2.7 $ 2.7 Total Current Regulatory Liabilities 2.7 2.7 2.7 Noncurrent: Deferred taxes due to customers 152.6 — — Accrued cost of removal 48.7 54.5 55.6 Unamortized purchased gas adjustments 50.3 1.9 2.0 Other 20.9 24.8 26.9 Total Noncurrent Regulatory Liabilities 272.5 81.2 84.5 Total Regulatory Liabilities $ 275.2 $ 83.9 $ 87.2 March 31, September 30, March 31, Spire Alabama 2018 2017 2017 Regulatory Assets: Current: Pension and postretirement benefit costs $ 7.1 $ 7.2 $ 6.8 Unamortized purchased gas adjustments 19.0 45.2 43.9 Other 6.0 12.2 4.4 Total Current Regulatory Assets 32.1 64.6 55.1 Noncurrent: Pension and postretirement benefit costs 71.2 72.6 94.4 Cost of removal 125.0 123.3 133.9 Other 2.7 1.1 1.0 Total Noncurrent Regulatory Assets 198.9 197.0 229.3 Total Regulatory Assets $ 231.0 $ 261.6 $ 284.4 Regulatory Liabilities: Current: RSE adjustment $ — $ 1.4 $ 1.1 Unbilled service margin — — 13.5 Refundable negative salvage 5.3 8.2 8.1 Other 5.5 2.4 2.4 Total Current Regulatory Liabilities 10.8 12.0 25.1 Noncurrent: Pension and postretirement benefit costs 30.8 32.2 27.6 Refundable negative salvage 0.6 4.1 4.9 Other 3.6 3.3 3.4 Total Noncurrent Regulatory Liabilities 35.0 39.6 35.9 Total Regulatory Liabilities $ 45.8 $ 51.6 $ 61.0 A portion of the Company’s and Spire Missouri’s regulatory assets are not earning a return, as shown in the table below: Spire Spire Missouri March 31, September 30, March 31, March 31, September 30, March 31, 2018 2017 2017 2018 2017 2017 Future income taxes due from customers $ 113.0 $ 170.5 $ 159.7 $ 111.4 $ 170.5 $ 159.7 Pension and postretirement benefit costs 185.8 198.5 241.0 185.8 198.5 241.0 Other 11.0 11.3 11.8 11.0 11.3 11.8 Total Regulatory Assets Not Earning a Return $ 309.8 $ 380.3 $ 412.5 $ 308.2 $ 380.3 $ 412.5 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 (IRS) 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 April 11, 2017, Spire Missouri East filed a general rate case docketed as GR-2017-0215, and concurrently, Spire Missouri West filed general rate case GR-2017-0216. On March 7, 2018, the MoPSC issued an Amended Report and Order, approving a base rate revenue requirement increase of $18.0 for Spire Missouri East and $15.2 for Spire Missouri West. The annualized Infrastructure System Replacement Surcharge (ISRS) amounts of $32.6 for Spire Missouri East and $16.4 for Spire Missouri West were reset to zero , resulting in a net decrease in revenues of $14.6 and $1.2 , respectively. These net amounts reflect decreases totaling approximately $33.0 resulting from the federal income tax rate reduction from the Tax Cuts and Jobs Act (see Note 11 , Income Taxes) and a related allowance to return excess accumulated deferred income taxes to customers in accordance with IRS normalization requirements. Tariffs reflecting the MoPSC’s Amended Report and Order went into effect on April 19, 2018. Included in the rate order were updates to the treatment of pension and other postretirement benefits. Effective April 19, 2018, the pension cost for Spire Missouri West included in customer rates was reduced from $9.9 to $5.5 per year, the pension cost included in the Spire Missouri East customer rates was increased from $15.5 to $29.0 per year, and the annual allowance for health care postretirement plans for Spire Missouri East was reduced from $9.5 to $8.6 . Over an amortization period of eight years , Spire Missouri East rates will also include the amortization of $173.0 of assets for pension and other postretirement benefits, and Spire Missouri West rates will be reduced by the amortization of a $26.2 net liability for pension and other postretirement benefits. Certain provisions of the MoPSC’s Amended Report and Order allow less future recovery of particular costs than previously estimated. Regulatory assets related to pension costs were reduced by $28.8 because the MoPSC has indicated that certain amounts established before 1997 are not recoverable. They also ordered that certain incentive compensation costs totaling $6.9 and $1.8 of assets related to buildings sold in 2014 be excluded from rate base. Rate case expenses totaling $0.9 were also disallowed. Though appeals are pending, management determined that the related assets should be written down or off in connection with the preparation of the financial statements for the second quarter of 2018. For both Spire Missouri and Spire, the charges totaled $38.4 for the three and six months ended March 31, 2018, and are included primarily in operation and maintenance expense on the statements of income and in other cash flows from operating activities on the statements of cash flows. The after-tax reduction to net income and earnings per share was $23.6 and $0.49 , respectively. The charges related to the long-standing pension and building assets, totaling $30.6 , are excluded in the determination of net economic earnings, as shown in Note 9 , Information by Operating Segment.

FINANCING ARRANGEMENTS AND LONG

FINANCING ARRANGEMENTS AND LONG-TERM DEBT	6 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
FINANCING ARRANGEMENTS AND LONG-TERM DEBT	FINANCING ARRANGEMENTS AND LONG-TERM DEBT On December 14, 2016, Spire, Spire Missouri and Spire Alabama entered into a syndicated revolving credit facility pursuant to a loan agreement with 11 banks, expiring December 14, 2021. 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. The agreement 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 March 31, 2018 , total debt was 54% of total capitalization for the consolidated Company, 48% for Spire Missouri, and 33% for Spire Alabama. There were no borrowings against this credit facility as of March 31, 2018, September 30, 2017, or March 31, 2017. On December 21, 2016, Spire established a commercial paper program (Program) pursuant to which Spire may issue short-term, unsecured commercial paper notes (Notes). Amounts available under the 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 Program at any time not to exceed $975.0 . The Notes may have maturities of up to 365 days from date of issue. As of March 31, 2018 , Notes outstanding under the Program totaled $391.7 . Of that amount, $175.8 and $82.3 were loaned to Spire Missouri and Spire Alabama, respectively, at Spire’s cost. Notes outstanding under the Program totaled $ 477.3 and $567.4 as of September 30, 2017, and March 31, 2017, respectively. On December 1, 2017, Spire Alabama entered into the First Supplement to Master Note Purchase Agreement with certain institutional investors. Pursuant to the terms of that supplement, on December 1, 2017, Spire Alabama issued and sold $30.0 in aggregate principal amount of its 4.02% Series 2017A Senior Notes due January 15, 2058, and on January 12, 2018, issued and sold $45.0 aggregate principal amount of its 3.92% Series 2017B Senior Notes due January 15, 2048, to those institutional investors. The notes bear interest from the date of issuance, payable semi-annually on the 15th day of July and January of each year, commencing on July 15, 2018. The notes are senior unsecured obligations of Spire Alabama, rank equal in right to payment with all its other senior unsecured indebtedness, and have make-whole and par call options. Spire Alabama used the proceeds from the sale of the notes to repay short-term debt and for general corporate purposes.

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	6 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
FAIR VALUE OF FINANCIAL INSTRUMENTS	FAIR VALUE OF FINANCIAL INSTRUMENTS 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 March 31, 2018 , September 30, 2017 , or March 31, 2017 . 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 6 , Fair Value Measurements, for information on financial instruments measured at fair value on a recurring basis. Classification of Estimated Fair Value Carrying Amount Fair Value Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Spire As of March 31, 2018 Cash and cash equivalents $ 17.8 $ 17.8 $ 17.8 $ — Short-term debt 391.7 391.7 — 391.7 Long-term debt, including current portion 2,179.4 2,241.3 — 2,241.3 As of September 30, 2017 Cash and cash equivalents $ 7.4 $ 7.4 $ 7.4 $ — Short-term debt 477.3 477.3 — 477.3 Long-term debt, including current portion 2,095.0 2,210.3 — 2,210.3 As of March 31, 2017 Cash and cash equivalents $ 19.6 $ 19.6 $ 19.6 $ — Short-term debt 567.4 567.4 — 567.4 Long-term debt 1,925.3 1,993.9 — 1,993.9 Spire Missouri As of March 31, 2018 Cash and cash equivalents $ 10.2 $ 10.2 $ 10.2 $ — Short-term debt 175.8 175.8 — 175.8 Long-term debt, including current portion 974.0 1,033.6 — 1,033.6 As of September 30, 2017 Cash and cash equivalents $ 2.5 $ 2.5 $ 2.5 $ — Short-term debt 203.0 203.0 — 203.0 Long-term debt, including current portion 973.9 1,056.9 — 1,056.9 As of March 31, 2017 Cash and cash equivalents $ 3.7 $ 3.7 $ 3.7 $ — Short-term debt 282.2 282.2 — 282.2 Long-term debt 804.3 870.1 — 870.1 Spire Alabama As of March 31, 2018 Short-term debt $ 82.3 $ 82.3 $ — $ 82.3 Long-term debt 322.5 332.7 — 332.7 As of September 30, 2017 Cash and cash equivalents $ 0.1 $ 0.1 $ 0.1 $ — Short-term debt 169.9 169.9 — 169.9 Long-term debt 247.8 269.4 — 269.4 As of March 31, 2017 Short-term debt $ 109.3 $ 109.3 $ — $ 109.3 Long-term debt 247.7 261.6 — 261.6

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	6 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	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. The mutual funds included in Level 2 are valued based on the closing net asset value per unit. 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 and derivative instruments with settlement dates more than one year into the future. 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. The Level 3 balances as of March 31, 2018 , September 30, 2017 , and March 31, 2017 , 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 March 31, 2018 ASSETS Gas Utility: US stock/bond mutual funds $ 19.1 $ 4.1 $ — $ — $ 23.2 NYMEX/ICE natural gas contracts 0.1 — — (0.1 ) — Gas Marketing: NYMEX/ICE natural gas contracts 0.2 3.3 — (3.5 ) — Natural gas commodity contracts — 7.4 0.1 (2.1 ) 5.4 Other: Interest rate swaps — 1.0 — — 1.0 Total $ 19.4 $ 15.8 $ 0.1 $ (5.7 ) $ 29.6 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 0.2 $ — $ — $ (0.2 ) $ — Gas Marketing: NYMEX/ICE natural gas contracts 0.6 9.8 — (10.4 ) — Natural gas commodity contracts — 14.3 — (2.1 ) 12.2 Total $ 0.8 $ 24.1 $ — $ (12.7 ) $ 12.2 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, 2017 ASSETS Gas Utility: US stock/bond mutual funds $ 18.3 $ 4.1 $ — $ — $ 22.4 NYMEX/ICE natural gas contracts 3.4 — — (3.4 ) — NYMEX gasoline and heating oil contracts 0.1 — — — 0.1 Gas Marketing: NYMEX/ICE natural gas contracts 1.3 1.3 — (2.1 ) 0.5 Natural gas commodity contracts — 6.8 0.1 (1.2 ) 5.7 Total $ 23.1 $ 12.2 $ 0.1 $ (6.7 ) $ 28.7 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 1.9 $ — $ — $ (1.9 ) $ — Gas Marketing: NYMEX/ICE natural gas contracts 1.8 0.3 — (2.1 ) — Natural gas commodity contracts — 8.4 — (1.2 ) 7.2 Other: Interest rate swaps — 0.9 — — 0.9 Total $ 3.7 $ 9.6 $ — $ (5.2 ) $ 8.1 As of March 31, 2017 ASSETS Gas Utility: US stock/bond mutual funds $ 17.7 $ 4.1 $ — $ — $ 21.8 NYMEX/ICE natural gas contracts 4.5 — — (1.8 ) 2.7 NYMEX gasoline and heating oil contracts 0.2 — — — 0.2 Gas Marketing: NYMEX/ICE natural gas contracts 1.0 3.6 — (4.4 ) 0.2 Natural gas commodity contracts — 6.2 0.2 (0.5 ) 5.9 Other: Interest rate swaps — 0.2 — — 0.2 Total $ 23.4 $ 14.1 $ 0.2 $ (6.7 ) $ 31.0 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 0.5 $ — $ — $ (0.5 ) $ — Gas Marketing: NYMEX/ICE natural gas contracts 2.1 3.9 — (6.0 ) — Natural gas commodity contracts — 6.5 — (0.5 ) 6.0 Total $ 2.6 $ 10.4 $ — $ (7.0 ) $ 6.0 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 March 31, 2018 ASSETS US stock/bond mutual funds $ 19.1 $ 4.1 $ — $ — $ 23.2 NYMEX/ICE natural gas contracts 0.1 — — (0.1 ) — Total $ 19.2 $ 4.1 $ — $ (0.1 ) $ 23.2 LIABILITIES NYMEX/ICE natural gas contracts $ 0.2 $ — $ — $ (0.2 ) $ — Total $ 0.2 $ — $ — $ (0.2 ) $ — As of September 30, 2017 ASSETS US stock/bond mutual funds $ 18.3 $ 4.1 $ — $ — $ 22.4 NYMEX/ICE natural gas contracts 3.4 — — (3.4 ) — NYMEX gasoline and heating oil contracts 0.1 — — — 0.1 Total $ 21.8 $ 4.1 $ — $ (3.4 ) $ 22.5 LIABILITIES NYMEX/ICE natural gas contracts $ 1.9 $ — $ — $ (1.9 ) $ — Total $ 1.9 $ — $ — $ (1.9 ) $ — As of March 31, 2017 ASSETS US stock/bond mutual funds $ 17.7 $ 4.1 $ — $ — $ 21.8 NYMEX/ICE natural gas contracts 4.5 — — (1.8 ) 2.7 NYMEX gasoline and heating oil contracts 0.2 — — — 0.2 Total $ 22.4 $ 4.1 $ — $ (1.8 ) $ 24.7 LIABILITIES NYMEX/ICE natural gas contracts $ 0.5 $ — $ — $ (0.5 ) $ — Total $ 0.5 $ — $ — $ (0.5 ) $ — Spire Alabama Spire Alabama occasionally utilizes a gasoline derivative program to stabilize the cost of fuel used in operations. As of March 31, 2018 , Spire Alabama had no outstanding derivative contracts. As of September 30, 2017 , and March 31, 2017 , the fair value of related gasoline contracts was not significant.

CONCENTRATIONS OF CREDIT RISK

CONCENTRATIONS OF CREDIT RISK	6 Months Ended
	Mar. 31, 2018
Risks and Uncertainties [Abstract]
CONCENTRATION OF CREDIT RISK	CONCENTRATIONS OF CREDIT RISK Other than in Spire Marketing, Spire has no significant concentrations of credit risk. A significant portion of Spire Marketing’s transactions are with (or are associated with) energy producers, utility companies, and pipelines. The concentration of transactions with these counterparties has the potential to affect the Company’s overall exposure to credit risk, either positively or negatively, in that each of these three groups may be affected similarly by changes in economic, industry, or other conditions. To manage this risk, as well as credit risk from significant counterparties in these and other industries, Spire Marketing has established procedures to determine the creditworthiness of its counterparties. These procedures include obtaining credit ratings and credit reports, analyzing counterparty financial statements to assess financial condition, and considering the industry environment in which the counterparty operates. This information is monitored on an ongoing basis. In some instances, Spire Marketing may require credit assurances such as prepayments, letters of credit, or parental guarantees. In addition, Spire Marketing may enter into netting arrangements to mitigate credit risk with counterparties in the energy industry with whom it conducts both sales and purchases of natural gas. Sales are typically made on an unsecured credit basis with payment due the month following delivery. Accounts receivable amounts are closely monitored and provisions for uncollectible amounts are accrued when losses are probable. Spire Marketing records accounts receivable, accounts payable, and prepayments for physical sales and purchases of natural gas on a gross basis. The amount included in its accounts receivable attributable to energy producers and their marketing affiliates totaled $15.6 at March 31, 2018 ( $9.6 reflecting netting arrangements). Spire Marketing’s accounts receivable attributable to utility companies and their marketing affiliates totaled $30.7 at March 31, 2018 ( $29.4 reflecting netting arrangements). Spire Marketing also has concentrations of credit risk with certain individually significant counterparties and with pipeline companies associated with its natural gas receivable amounts. At March 31, 2018 , the amounts included in accounts receivable from its five largest counterparties (in terms of net accounts receivable exposure) totaled $16.1 ( $14.9 reflecting netting arrangements). None of these five counterparties are rated, but three are subsidiaries of investment-grade rated companies.

PENSION PLANS AND OTHER POSTRET

PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS	6 Months Ended
	Mar. 31, 2018
Defined Contribution Plan [Abstract]
PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS	PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS Pension Plans Spire and the Utilities maintain pension plans for their employees. The Missouri Utilities have non-contributory, defined benefit, trusteed forms of pension plans covering the majority of their employees. Plan assets consist primarily of corporate and United States (US) 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 US equities with varying strategies, global equities, alternative investments, and fixed income investments. The net periodic pension cost included the following components: Three Months Ended March 31, Six Months Ended March 31, 2018 2017 2018 2017 Spire Service cost – benefits earned during the period $ 5.2 $ 5.2 $ 10.4 $ 10.5 Interest cost on projected benefit obligation 6.9 6.9 13.8 13.8 Expected return on plan assets (9.5 ) (9.7 ) (19.2 ) (19.6 ) Amortization of prior service (credit) cost (0.2 ) 0.3 (0.5 ) 0.5 Amortization of actuarial loss 2.9 3.2 6.0 6.6 Loss on lump-sum settlements 9.4 11.9 9.4 11.9 Subtotal 14.7 17.8 19.9 23.7 Regulatory adjustment 24.0 (7.4 ) 28.3 (2.8 ) Net pension cost $ 38.7 $ 10.4 $ 48.2 $ 20.9 Spire Missouri Service cost – benefits earned during the period $ 3.2 $ 3.3 $ 6.5 $ 6.6 Interest cost on projected benefit obligation 4.9 4.9 9.8 9.7 Expected return on plan assets (7.0 ) (7.1 ) (14.2 ) (14.4 ) Amortization of prior service cost 0.2 0.3 0.4 0.5 Amortization of actuarial loss 2.5 2.8 5.1 5.7 Loss on lump-sum settlements 9.4 11.5 9.4 11.5 Subtotal 13.2 15.7 17.0 19.6 Regulatory adjustment 21.9 (8.6 ) 24.3 (5.8 ) Net pension cost $ 35.1 $ 7.1 $ 41.3 $ 13.8 Spire Alabama Service cost – benefits earned during the period $ 1.7 $ 1.5 $ 3.3 $ 3.1 Interest cost on projected benefit obligation 1.4 1.5 2.8 3.0 Expected return on plan assets (1.7 ) (1.8 ) (3.4 ) (3.6 ) Amortization of prior service credit (0.4 ) — (0.9 ) — Amortization of actuarial loss 0.4 0.4 0.9 0.9 Loss on lump-sum settlements — 0.4 — 0.4 Subtotal 1.4 2.0 2.7 3.8 Regulatory adjustment 1.9 1.1 3.6 2.7 Net pension cost $ 3.3 $ 3.1 $ 6.3 $ 6.5 Pursuant to the provisions of the Missouri Utilities’ 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 gains or losses. In the quarter ended March 31, 2018, the two Spire Missouri plans met the criteria for settlement recognition, resulting in the remeasurement of the obligation of the plans using updated census data and assumptions for discount and mortality. For these plans the total lump-sum payments recognized as settlements for plan remeasurement was $39.5 and the lump-sum settlements resulted in losses of $9.4 . As part of the remeasurement, the discount rate on the one Missouri plan was updated to 4.0% from 3.75% , while the other Missouri plan had its discount rate updated to 4.0% from 3.70% . In the quarter ended March 31, 2017, a Spire Missouri plan and one of the Spire Alabama plans met the criteria for settlement recognition. The total lump-sum payments recognized as settlements for plan remeasurement were $36.3 and $1.9 for the Spire Missouri plan and Spire Alabama plan, respectively. The lump-sum settlements resulted in losses of $11.5 and $0.4 for the Spire Missouri plan and Spire Alabama plan, respectively. In the second quarter of fiscal 2018, the MoPSC disallowed recovery of $28.8 in pension assets. This amount was expensed during the quarter, and is reflected in the regulatory adjustment for both Spire Missouri and Spire. This adjustment is discussed further in Note 3 , Regulatory Matters. 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 2018 contributions to Spire Missouri’s pension plans through March 31, 2018 , were $13.5 to the qualified trusts and none to non-qualified plans. There were no fiscal 2018 contributions to the Spire Alabama pension plans through March 31, 2018 . Contributions to the Missouri Utilities’ pension plans for the remainder of fiscal 2018 are anticipated to be $22.4 to the qualified trusts and $0.5 to the non-qualified plans. No contributions to Spire Alabama’s pension plans are expected to be required for the remainder of fiscal 2018. 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, the Spire Missouri West 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 March 31, Six Months Ended March 31, 2018 2017 2018 2017 Spire Service cost – benefits earned during the period $ 2.4 $ 2.7 $ 4.7 $ 5.5 Interest cost on accumulated postretirement benefit obligation 2.2 2.2 4.4 4.3 Expected return on plan assets (3.5 ) (3.4 ) (7.0 ) (6.8 ) Amortization of prior service credit (0.1 ) — (0.1 ) — Amortization of actuarial loss 0.2 0.6 0.4 1.2 Subtotal 1.2 2.1 2.4 4.2 Regulatory adjustment — (0.8 ) 0.1 (1.6 ) Net postretirement benefit cost $ 1.2 $ 1.3 $ 2.5 $ 2.6 Spire Missouri Service cost – benefits earned during the period $ 2.3 $ 2.6 $ 4.5 $ 5.2 Interest cost on accumulated postretirement benefit obligation 1.8 1.7 3.6 3.4 Expected return on plan assets (2.5 ) (2.2 ) (4.9 ) (4.5 ) Amortization of prior service cost — — 0.1 0.1 Amortization of actuarial loss 0.2 0.7 0.4 1.3 Subtotal 1.8 2.8 3.7 5.5 Regulatory adjustment 0.5 (0.3 ) 1.0 (0.7 ) Net postretirement benefit cost $ 2.3 $ 2.5 $ 4.7 $ 4.8 Spire Alabama Service cost – benefits earned during the period $ 0.1 $ 0.1 $ 0.1 $ 0.2 Interest cost on accumulated postretirement benefit obligation 0.3 0.4 0.7 0.8 Expected return on plan assets (1.0 ) (1.1 ) (2.0 ) (2.2 ) Amortization of prior service credit (0.1 ) — (0.2 ) (0.1 ) Amortization of actuarial gain — (0.1 ) — (0.1 ) Subtotal (0.7 ) (0.7 ) (1.4 ) (1.4 ) Regulatory adjustment (0.5 ) (0.5 ) (0.9 ) (0.9 ) Net postretirement benefit income $ (1.2 ) $ (1.2 ) $ (2.3 ) $ (2.3 ) Missouri and Alabama state law 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 $1.7 in contributions to the postretirement plans through March 31, 2018 , for the Missouri Utilities. Contributions to the postretirement plans for the remainder of fiscal 2018 are anticipated to be $5.2 to the qualified trusts and $0.8 paid directly to participants from the Missouri Utilities’ funds. For Spire Alabama, there were no contributions to the postretirement plans during the first six months of fiscal 2018, and none are expected to be required for the remainder of the fiscal year.

INFORMATION BY OPERATING SEGMEN

INFORMATION BY OPERATING SEGMENT	6 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
INFORMATION BY OPERATING SEGMENT	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 includes: • unallocated corporate costs, including certain debt and associated interest costs; • Spire STL Pipeline LLC, a subsidiary of Spire planning construction and operation of a proposed 65-mile Federal Energy Regulatory Commission (FERC)-regulated pipeline to deliver natural gas into eastern Missouri; • physical natural gas storage operations, include the acquisition of an 80% voting interest in Ryckman Creek Resources, LLC, in December 2017; and • Spire’s subsidiaries engaged in the operation of a propane pipeline, 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, sales of natural gas from Spire Missouri 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 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 other non-recurring or unusual items such as certain regulatory, legislative, or GAAP standard-setting actions. In fiscal 2018, these items include the revaluation of deferred tax assets and liabilities due to the federal Tax Cuts and Jobs Act (see Note 11 , Income Taxes) and the write-off of certain long-standing assets as a result of our Missouri rate proceedings (see Note 3 , Regulatory Matters). Gas Utility Gas Marketing Other Eliminations Consolidated Three Months Ended March 31, 2018 Operating Revenues: Revenues from external customers $ 790.6 $ 21.3 $ 1.5 $ — $ 813.4 Intersegment revenues 0.2 — 2.9 (3.1 ) — Total Operating Revenues 790.8 21.3 4.4 (3.1 ) 813.4 Operating Expenses: Gas Utility Natural and propane gas 403.2 — — (19.5 ) 383.7 Operation and maintenance 145.8 — — (2.2 ) 143.6 Depreciation and amortization 41.1 — — — 41.1 Taxes, other than income taxes 58.0 — — — 58.0 Total Gas Utility Operating Expenses 648.1 — — (21.7 ) 626.4 Gas Marketing and Other — 20.2 6.4 18.6 45.2 Total Operating Expenses 648.1 20.2 6.4 (3.1 ) 671.6 Operating Income (Loss) $ 142.7 $ 1.1 $ (2.0 ) $ — $ 141.8 Net Economic Earnings (Loss) $ 131.7 $ 10.2 $ (4.7 ) $ — $ 137.2 Gas Utility Gas Marketing Other Eliminations Consolidated Three Months Ended March 31, 2017 Operating Revenues: Revenues from external customers $ 641.1 $ 22.2 $ 0.1 $ — $ 663.4 Intersegment revenues 2.6 — 1.7 (4.3 ) — Total Operating Revenues 643.7 22.2 1.8 (4.3 ) 663.4 Operating Expenses: Gas Utility Natural and propane gas 275.6 — — (21.3 ) 254.3 Operation and maintenance 99.3 — — (0.9 ) 98.4 Depreciation and amortization 37.9 — — — 37.9 Taxes, other than income taxes 48.3 — — — 48.3 Total Gas Utility Operating Expenses 461.1 — — (22.2 ) 438.9 Gas Marketing and Other — 23.9 2.3 17.9 44.1 Total Operating Expenses 461.1 23.9 2.3 (4.3 ) 483.0 Operating Income (Loss) $ 182.6 $ (1.7 ) $ (0.5 ) $ — $ 180.4 Net Economic Earnings (Loss) $ 112.2 $ — $ (3.2 ) $ — $ 109.0 Gas Utility Gas Marketing Other Eliminations Consolidated Six Months Ended March 31, 2018 Operating Revenues: Revenues from external customers $ 1,332.5 $ 40.9 $ 1.8 $ — $ 1,375.2 Intersegment revenues 0.3 — 5.4 (5.7 ) — Total Operating Revenues 1,332.8 40.9 7.2 (5.7 ) 1,375.2 Operating Expenses: Gas Utility Natural and propane gas 666.6 — — (42.1 ) 624.5 Operation and maintenance 245.6 — — (4.1 ) 241.5 Depreciation and amortization 81.4 — — — 81.4 Taxes, other than income taxes 94.7 — — — 94.7 Total Gas Utility Operating Expenses 1,088.3 — — (46.2 ) 1,042.1 Gas Marketing and Other — 34.8 10.9 40.5 86.2 Total Operating Expenses 1,088.3 34.8 10.9 (5.7 ) 1,128.3 Operating Income (Loss) $ 244.5 $ 6.1 $ (3.7 ) $ — $ 246.9 Net Economic Earnings (Loss) $ 191.2 $ 13.8 $ (9.9 ) $ — $ 195.1 Six Months Ended March 31, 2017 Operating Revenues: Revenues from external customers $ 1,113.4 $ 43.9 $ 1.2 $ — $ 1,158.5 Intersegment revenues 7.0 — 2.4 (9.4 ) — Total Operating Revenues 1,120.4 43.9 3.6 (9.4 ) 1,158.5 Operating Expenses: Gas Utility Natural and propane gas 490.1 — — (42.0 ) 448.1 Operation and maintenance 199.8 — — (2.0 ) 197.8 Depreciation and amortization 75.6 — — — 75.6 Taxes, other than income taxes 81.7 — — — 81.7 Total Gas Utility Operating Expenses 847.2 — — (44.0 ) 803.2 Gas Marketing and Other — 46.9 4.3 34.6 85.8 Total Operating Expenses 847.2 46.9 4.3 (9.4 ) 889.0 Operating Income (Loss) $ 273.2 $ (3.0 ) $ (0.7 ) $ — $ 269.5 Net Economic Earnings (Loss) $ 164.0 $ 1.4 $ (8.9 ) $ — $ 156.5 The Company’s total assets by segment were as follows: March 31, September 30, March 31, 2018 2017 2017 Total Assets: Gas Utility $ 5,484.3 $ 5,551.2 $ 5,290.8 Gas Marketing 208.6 246.2 218.2 Other 2,211.9 2,239.5 2,199.1 Eliminations (1,318.0 ) (1,490.2 ) (1,451.4 ) Total Assets $ 6,586.8 $ 6,546.7 $ 6,256.7 The following table reconciles the Company’s net economic earnings to net income. Three Months Ended March 31, Six Months Ended March 31, 2018 2017 2018 2017 Net Income $ 98.2 $ 108.0 $ 214.2 $ 153.2 Adjustments, pre-tax: Missouri regulatory adjustments 30.6 — 30.6 — Unrealized loss on energy-related derivative contracts 11.8 1.6 12.6 5.4 Lower of cost or market inventory adjustments — 0.1 — — Realized gain on economic hedges prior to sale of the physical commodity (0.2 ) (0.1 ) (0.3 ) (0.2 ) Acquisition, divestiture and restructuring activities 2.0 0.1 3.7 0.2 Income tax effect of adjustments (11.1 ) (0.7 ) (11.7 ) (2.1 ) Effects of the Tax Cuts and Jobs Act 5.9 — (54.0 ) — Net Economic Earnings $ 137.2 $ 109.0 $ 195.1 $ 156.5

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Commitments The Company and the Utilities have entered into contracts with various counterparties, expiring on dates through 2031 , for the storage, transportation, and supply of natural gas. Minimum payments required under the contracts in place at March 31, 2018 , are estimated at $1,117.9 , $465.1 , and $288.5 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. On April 27, 2018, Spire STL Pipeline entered into a construction contract. Construction is subject to project approvals by the FERC and state and local authorities. Though unit pricing generally applies, Spire STL Pipeline currently estimates the total value to be approximately $95.0 , with the primary construction period currently scheduled for the second half of calendar 2018. Spire STL Pipeline has the right to terminate at any time with payment for the value of work performed plus costs incurred. 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 , when it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. 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 consolidated 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 On June 14, 2017, Spire filed a lawsuit against Cellular South, Inc. d/b/a C-Spire in federal district court for the Southern District of Alabama, Civil Action 17-00266-KD-N, seeking a declaratory order that Spire’s SPIRE trademarks do not infringe upon Cellular South’s C-SPIRE trademarks, and that Spire is entitled to federal registration of its trademarks. In prior proceedings before the United States Patent and Trademark Office, Cellular South filed oppositions to Spire’s attempts to register the SPIRE name, the SPIRE logo and the SPIRE LOGO + HANDSHAKE trademarks. In answer to Spire’s lawsuit, Cellular South filed counterclaims alleging infringement and unfair business practices, and seeking a declaration of infringement and that SPIRE marks are not registrable by Spire. On April 23, 2018, the parties mutually agreed to dismiss all litigation concerning the matter and enter into a coexistence agreement for the use of their respective trademarks. Since April 2012, a total of 14 lawsuits encompassing more than 1,600 plaintiffs have been filed against Spire Gulf in Mobile County Circuit Court alleging that in the first half of 2008, Spire Gulf spilled tert-butyl mercaptan, an odorant added to natural gas for safety reasons, in Eight Mile, Alabama. All of the lawsuits have been substantially settled, with the exception of 31 individuals who rejected their settlement offers and whose claims remain pending. Those remaining claims allege nuisance, fraud and negligence causes of actions, and seek unspecified compensatory and punitive damages. A claim has been made against the insurance carriers requesting reimbursement for costs accrued in respect to this spill, and a related receivable has been recorded. The Company does not expect potential liabilities that may arise from these lawsuits to have a material impact on its future financial condition or results of operations. Spire Missouri Spire Missouri has identified three former MGP sites in the city of St. Louis, Missouri (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) and such claim is currently being investigated. In conjunction with redevelopment of one of the sites, Spire Missouri and another former owner of the site entered into an agreement (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. The amount paid by Spire Missouri did not materially impact the financial condition, results of operations, or cash flows of the Company. 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. Pending MDNR approval, which has not occurred to date, the remedial investigation of the site will begin. 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 is requesting more information from the EPA, some of which will 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 the MGP sites. While some of the insurers have denied coverage and reserved their rights, Spire Missouri continues to discuss potential reimbursements with 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, MGE 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 Missouri Utilities’ 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 actions 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 On December 17, 2013, an incident occurred at a Housing Authority apartment complex in Birmingham, Alabama that resulted in one fatality, personal injuries and property damage. Spire Alabama cooperated with the National Transportation Safety Board (NTSB) which investigated the incident. The NTSB report of findings was issued on March 30, 2016 and no safety recommendations, fines, or penalties were contained therein. Spire Alabama has been named as a defendant in several lawsuits arising from the incident, some of which remain pending. 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.

INCOME TAXES

INCOME TAXES	6 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Tax Cuts and Jobs Act (the TCJA) was signed into law on December 22, 2017, with an effective date of January 1, 2018, for substantially all of the provisions. This comprehensive act includes significant reform of the current income tax code including changes in the calculation for business entities and a reduction in the corporate federal income tax rate from 35% to 21% . The specific provisions related to regulated public utilities in the TCJA generally allow for the continued deductibility of interest expense, the elimination of full expensing for tax purposes of certain property acquired after September 27, 2017, and the continuation of certain rate normalization requirements for accelerated depreciation benefits. ASC Topic 740, Income Taxes, requires that the effects of changes in tax laws be recognized in the period in which the new law is enacted, or the quarter ended December 31, 2017. It also requires deferred tax assets and liabilities to be measured at the enacted tax rate expected to apply when temporary differences are to be realized or settled. For the Company’s regulated entities, the changes in deferred taxes related to the regulated operations are recorded as either an offset to or creation of a regulatory asset or liability and may be subject to refund to customers in future periods. The changes in deferred taxes that are not associated with rate making (including all changes for the Company’s unregulated operations) are recorded as adjustments to deferred tax expense. The Company has recorded TCJA impacts and reflected those amounts in the March 31, 2018, financial statements. The amounts recorded are based on information known and reasonable estimates used as of that date, but are subject to change based on a number of factors, including further actions of regulators, the Company filing its tax returns for the year ended September 30, 2017, and completion of the Company’s interim and annual financial statements for the year ending September 30, 2018. The items recorded include the impact of the federal income tax rate reduction and the revaluation of the deferred tax assets and liabilities. In the second quarter of fiscal 2018, the estimated amounts were adjusted to account for effects of the March MoPSC order, including the lower federal tax rate impact for the quarter and reductions in net deferred tax liabilities related to regulatory assets determined not to be recoverable and removed from rate base. The updated total amounts recorded, which had no impact on cash flows for the six months ended March 31, 2018, are presented in the table below. Spire Spire Missouri Spire Alabama Adjustment to deferred tax assets $ — $ — $ (60.8 ) Adjustment to deferred tax liabilities (299.5 ) (268.2 ) — Adjustment to deferred income tax expense (69.4 ) (54.6 ) 59.2 Adjustment to regulatory assets (59.4 ) (61.0 ) 1.6 Adjustment to regulatory liabilities 170.7 152.6 — As indicated in Note 1 , Summary of Significant Accounting Policies, the Company’s regulated operations accounting for income taxes is impacted by ASC 980, Regulated Operations . Reductions in deferred income tax balances due to the reduction in the corporate income tax rate will result in amounts previously collected from utility customers for these deferred taxes to be refundable to such customers, generally through reductions in future rates. The TCJA includes provisions that stipulate how these excess deferred taxes are to be passed back to customers for certain accelerated tax depreciation benefits. Potential refunds of other deferred taxes will be determined by state regulators.

SUMMARY OF SIGNIFICANT ACCOUN19

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	6 Months Ended
	Mar. 31, 2018
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), as well as Spire Missouri Inc. (Spire Missouri or the Missouri Utilities) and Spire Alabama Inc. (Spire Alabama). Spire Missouri and Spire Alabama are wholly owned subsidiaries of the Company. 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 of the disclosures required for complete financial statements. In the opinion of management, the accompanying unaudited financial statements include all adjustments (consisting of only normal recurring 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, 2017 . 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. At the end of December 2017, a subsidiary of the Company acquired an 80% voting interest in Ryckman Creek Resources, LLC, which owns and operates a natural gas storage facility in Wyoming. The transaction was valued at $24.8 , subject to customary post-closing adjustments, and was completed with $16.0 of cash and a $10.0 non-interest-bearing promissory note valued at $8.8 . A tentative purchase price allocation to the assets acquired and liabilities assumed is reflected in the Company’s consolidated balance sheet as of March 31, 2018. Management is evaluating certain fair value accounting impacts, and any related adjustments will be recorded later this year. Results of operations are included in the Company’s consolidated financial statements since the acquisition date. The redeemable noncontrolling interest, which was shown in permanent equity at the end of the first quarter, is shown as temporary equity on the balance sheet.
REVENUE RECOGNITION	REVENUE RECOGNITION – The Utilities read meters and bill customers on monthly cycles. The Missouri Utilities, Spire Gulf and Spire Mississippi record their gas utility revenues from gas sales and transportation services on an accrual basis that includes estimated amounts for gas delivered but not yet billed. The accruals for unbilled revenues are reversed in the subsequent accounting period when meters are actually read and customers are billed. The amounts of accrued unbilled revenues for Spire Missouri at March 31, 2018 , September 30, 2017 , and March 31, 2017 , were $85.2 , $30.1 , and $66.7 , respectively. Spire Alabama records natural gas distribution revenues in accordance with the tariff established by the Alabama Public Service Commission (APSC). Unbilled revenue is accrued in an amount equal to the related gas cost, as profit margin is not considered earned until billed. The amounts of accrued unbilled revenues for Spire Alabama at March 31, 2018 , September 30, 2017 , and March 31, 2017 were $5.3 , $1.9 , and $13.5 , respectively. Spire’s other subsidiaries, including Spire Marketing, record revenues when earned, either when the product is delivered or when services are performed. In the course of its business, Spire Marketing enters 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 using a gross presentation. 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.
GROSS RECEIPTS AND SALES TAXES	GROSS RECEIPTS AND SALES TAXES – Gross receipts taxes associated with the Company’s natural gas utility services are imposed on the Utilities and billed to their customers. The revenue and expense amounts are recorded gross in the “Operating Revenues” and “Taxes, other than income taxes” lines, respectively, in the statements of 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 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.
TRANSACTIONS WITH AFFILIATES	TRANSACTIONS WITH AFFILIATES – Transactions between affiliates of the Company have been eliminated from the consolidated statements of Spire.
NEW ACCOUNTING PRONOUNCEMENTS	NEW ACCOUNTING PRONOUNCEMENTS – In May 2014, the FASB issued Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers . Under the new standard, an entity will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In doing so, companies may need to use more judgment and make more estimates than under current guidance. ASU No. 2014-09 also requires disclosures that will enable users of financial statements to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. Existing alternative revenue program guidance, though excluded by the FASB in updating specific guidance associated with revenue from contracts with customers, was relocated without substantial modification to accounting guidance for rate-regulated entities. It will require separate presentation of such revenues in the statement of income. Entities have the option of using either a full retrospective or modified retrospective approach to adopting this guidance. In August 2015, the FASB issued ASU No. 2015-14, which made the guidance in ASU No. 2014-09 effective for fiscal years beginning after December 15, 2017, and interim periods within those years. In 2016 and 2017, the FASB issued related ASU Nos. 2016-08, 2016-10, 2016-11, 2016-12, 2016-20, and 2017-14, which further modified the standards for accounting for revenue. The Company, Spire Missouri and Spire Alabama have nearly completed their evaluation of their sources of revenue and related contracts, plan to adopt the new guidance in the first quarter of fiscal 2019 using the modified retrospective approach, and expect no material effect on their financial position, results of operations, or cash flows. In February 2016, the FASB issued ASU No. 2016-02, Leases . The new standard requires lessees to recognize a right-of-use asset and lease liability for almost all lease contracts based on the present value of lease payments. There is an exemption for short-term leases. The ASU provides new guidelines for identifying and classifying a lease, and classification affects the pattern and income statement line item for the related expense. This update will be applied using a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. ASU No. 2018-01, issued in January 2018, clarifies the related transition and accounting for existing and new or modified land easements. The ASUs are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company, Spire Missouri and Spire Alabama are currently assessing the timing and impacts of adopting these standards, which must be adopted by the first quarter of fiscal 2020. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments . The standard introduces new guidance for the accounting for credit losses on instruments within its scope, including trade receivables. It is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, and may be adopted a year earlier. The new guidance will be initially applied through a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. The Company, Spire Missouri and Spire Alabama are currently assessing the timing and impacts of adopting this standard, which must be adopted by the first quarter of fiscal 2021. In March 2017, the FASB issued ASU No. 2017-07, Compensation – Retirement Benefits: Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost . The amended guidance requires that the service cost component of pension and postretirement benefit costs be presented within the same line item in the income statement as other compensation costs (except for the amount being capitalized), while other components are to be presented outside the subtotal of operating income and are no longer eligible for capitalization. The ASU is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. The amended guidance will be applied retrospectively for income statement presentation and prospectively for capitalization. The Company, Spire Missouri and Spire Alabama are currently assessing the regulatory and other impacts of adopting this standard, which must be adopted by the first quarter of fiscal 2019. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities . The amendments in this ASU more closely align the results of hedge accounting with risk management activities through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results in the financial statements. They are effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, and early application is permitted. The Company, Spire Missouri and Spire Alabama are currently assessing the effects of this new guidance, as well as the timing of adoption.

SUMMARY OF SIGNIFICANT ACCOUN20

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	6 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Schedule of gross receipts taxes	The following table presents gross receipts and sales taxes recorded as revenues: Three Months Ended March 31, Six Months Ended March 31, 2018 2017 2018 2017 Spire $ 43.6 $ 34.3 $ 66.7 $ 53.7 Spire Missouri 30.6 25.5 46.8 39.6 Spire Alabama 11.6 7.7 17.2 11.9
Schedule of inter-company transactions	In addition, Spire Missouri’s other transactions with affiliates included: Three Months Ended March 31, Six Months Ended March 31, 2018 2017 2018 2017 Purchases of natural gas from Spire Marketing $ 19.3 $ 21.0 $ 41.6 $ 41.5 Sales of natural gas to Spire Marketing 0.2 2.7 0.3 6.3 Transportation services received from Spire NGL Inc. 0.2 0.2 0.5 0.5
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. March 31, September 30, March 31, 2018 2017 2017 Spire $ 29.1 $ 41.0 $ 9.2 Spire Missouri 17.9 28.9 3.3 Spire Alabama 7.0 9.4 5.3

EARNINGS PER COMMON SHARE (Tabl

EARNINGS PER COMMON SHARE (Tables)	6 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Common Share	Spire Three Months Ended March 31, Six Months Ended March 31, 2018 2017 2018 2017 Basic Earnings Per Share: Net Income $ 98.2 $ 108.0 $ 214.2 $ 153.2 Less: Income allocated to participating securities 0.2 0.2 0.5 0.4 Net Income Available to Common Shareholders $ 98.0 $ 107.8 $ 213.7 $ 152.8 Weighted Average Shares Outstanding (in millions) 48.2 45.6 48.2 45.6 Basic Earnings Per Share of Common Stock $ 2.03 $ 2.36 $ 4.43 $ 3.35 Diluted Earnings Per Share: Net Income $ 98.2 $ 108.0 $ 214.2 $ 153.2 Less: Income allocated to participating securities 0.2 0.2 0.5 0.4 Net Income Available to Common Shareholders $ 98.0 $ 107.8 $ 213.7 $ 152.8 Weighted Average Shares Outstanding (in millions) 48.2 45.6 48.2 45.6 Dilutive Effect of Restricted Stock and Restricted Stock Units (in millions)* 0.2 0.1 0.2 0.1 Weighted Average Diluted Shares (in millions) 48.4 45.7 48.4 45.7 Diluted Earnings Per Share of Common Stock $ 2.03 $ 2.36 $ 4.42 $ 3.34 * Calculation excludes certain outstanding 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 0.4 0.5 0.4 0.5

REGULATORY MATTERS (Tables)

REGULATORY MATTERS (Tables)	6 Months Ended
	Mar. 31, 2018
Regulated Operations [Abstract]
Schedule of regulatory assets	The following regulatory assets and regulatory liabilities, including purchased gas adjustments, were reflected in the balance sheets of the Company, Spire Missouri and Spire Alabama as of March 31, 2018 , September 30, 2017 , and March 31, 2017 . March 31, September 30, March 31, Spire 2018 2017 2017 Regulatory Assets: Current: Pension and postretirement benefit costs $ 43.0 $ 42.2 $ 41.7 Unamortized purchased gas adjustments 32.6 102.6 61.0 Other 22.1 30.7 23.1 Total Current Regulatory Assets 97.7 175.5 125.8 Noncurrent: Future income taxes due from customers 113.0 170.5 159.7 Pension and postretirement benefit costs 358.2 404.7 461.8 Cost of removal 125.0 123.3 133.9 Unamortized purchased gas adjustments — 9.9 1.1 Energy efficiency 31.3 29.0 27.0 Other 46.1 53.7 44.2 Total Noncurrent Regulatory Assets 673.6 791.1 827.7 Total Regulatory Assets $ 771.3 $ 966.6 $ 953.5 Regulatory Liabilities: Current: Rate Stabilization and Equalization (RSE) adjustment $ — $ 1.4 $ 1.1 Unbilled service margin — — 13.5 Refundable negative salvage 5.3 8.2 8.1 Unamortized purchased gas adjustments 1.5 1.0 1.6 Other 15.4 12.0 7.0 Total Current Regulatory Liabilities 22.2 22.6 31.3 Noncurrent: Deferred taxes due to customers 170.7 — — Pension and postretirement benefit costs 30.8 32.2 27.6 Refundable negative salvage 0.6 4.1 4.9 Accrued cost of removal 71.0 83.8 75.3 Unamortized purchased gas adjustments 50.3 1.9 2.0 Other 29.7 35.2 34.3 Total Noncurrent Regulatory Liabilities 353.1 157.2 144.1 Total Regulatory Liabilities $ 375.3 $ 179.8 $ 175.4 March 31, September 30, March 31, Spire Missouri 2018 2017 2017 Regulatory Assets: Current: Pension and postretirement benefit costs $ 34.9 $ 34.9 $ 34.8 Unamortized purchased gas adjustments 13.5 57.4 17.1 Other 3.3 3.3 3.4 Total Current Regulatory Assets 51.7 95.6 55.3 Noncurrent: Future income taxes due from customers 111.4 170.5 159.7 Pension and postretirement benefit costs 279.0 322.7 358.3 Unamortized purchased gas adjustments — 9.9 1.1 Energy efficiency 31.3 29.0 27.0 Other 24.9 25.7 23.3 Total Noncurrent Regulatory Assets 446.6 557.8 569.4 Total Regulatory Assets $ 498.3 $ 653.4 $ 624.7 Regulatory Liabilities: Current: Other $ 2.7 $ 2.7 $ 2.7 Total Current Regulatory Liabilities 2.7 2.7 2.7 Noncurrent: Deferred taxes due to customers 152.6 — — Accrued cost of removal 48.7 54.5 55.6 Unamortized purchased gas adjustments 50.3 1.9 2.0 Other 20.9 24.8 26.9 Total Noncurrent Regulatory Liabilities 272.5 81.2 84.5 Total Regulatory Liabilities $ 275.2 $ 83.9 $ 87.2 March 31, September 30, March 31, Spire Alabama 2018 2017 2017 Regulatory Assets: Current: Pension and postretirement benefit costs $ 7.1 $ 7.2 $ 6.8 Unamortized purchased gas adjustments 19.0 45.2 43.9 Other 6.0 12.2 4.4 Total Current Regulatory Assets 32.1 64.6 55.1 Noncurrent: Pension and postretirement benefit costs 71.2 72.6 94.4 Cost of removal 125.0 123.3 133.9 Other 2.7 1.1 1.0 Total Noncurrent Regulatory Assets 198.9 197.0 229.3 Total Regulatory Assets $ 231.0 $ 261.6 $ 284.4 Regulatory Liabilities: Current: RSE adjustment $ — $ 1.4 $ 1.1 Unbilled service margin — — 13.5 Refundable negative salvage 5.3 8.2 8.1 Other 5.5 2.4 2.4 Total Current Regulatory Liabilities 10.8 12.0 25.1 Noncurrent: Pension and postretirement benefit costs 30.8 32.2 27.6 Refundable negative salvage 0.6 4.1 4.9 Other 3.6 3.3 3.4 Total Noncurrent Regulatory Liabilities 35.0 39.6 35.9 Total Regulatory Liabilities $ 45.8 $ 51.6 $ 61.0 A portion of the Company’s and Spire Missouri’s regulatory assets are not earning a return, as shown in the table below: Spire Spire Missouri March 31, September 30, March 31, March 31, September 30, March 31, 2018 2017 2017 2018 2017 2017 Future income taxes due from customers $ 113.0 $ 170.5 $ 159.7 $ 111.4 $ 170.5 $ 159.7 Pension and postretirement benefit costs 185.8 198.5 241.0 185.8 198.5 241.0 Other 11.0 11.3 11.8 11.0 11.3 11.8 Total Regulatory Assets Not Earning a Return $ 309.8 $ 380.3 $ 412.5 $ 308.2 $ 380.3 $ 412.5
Schedule of regulatory liabilities	The following regulatory assets and regulatory liabilities, including purchased gas adjustments, were reflected in the balance sheets of the Company, Spire Missouri and Spire Alabama as of March 31, 2018 , September 30, 2017 , and March 31, 2017 . March 31, September 30, March 31, Spire 2018 2017 2017 Regulatory Assets: Current: Pension and postretirement benefit costs $ 43.0 $ 42.2 $ 41.7 Unamortized purchased gas adjustments 32.6 102.6 61.0 Other 22.1 30.7 23.1 Total Current Regulatory Assets 97.7 175.5 125.8 Noncurrent: Future income taxes due from customers 113.0 170.5 159.7 Pension and postretirement benefit costs 358.2 404.7 461.8 Cost of removal 125.0 123.3 133.9 Unamortized purchased gas adjustments — 9.9 1.1 Energy efficiency 31.3 29.0 27.0 Other 46.1 53.7 44.2 Total Noncurrent Regulatory Assets 673.6 791.1 827.7 Total Regulatory Assets $ 771.3 $ 966.6 $ 953.5 Regulatory Liabilities: Current: Rate Stabilization and Equalization (RSE) adjustment $ — $ 1.4 $ 1.1 Unbilled service margin — — 13.5 Refundable negative salvage 5.3 8.2 8.1 Unamortized purchased gas adjustments 1.5 1.0 1.6 Other 15.4 12.0 7.0 Total Current Regulatory Liabilities 22.2 22.6 31.3 Noncurrent: Deferred taxes due to customers 170.7 — — Pension and postretirement benefit costs 30.8 32.2 27.6 Refundable negative salvage 0.6 4.1 4.9 Accrued cost of removal 71.0 83.8 75.3 Unamortized purchased gas adjustments 50.3 1.9 2.0 Other 29.7 35.2 34.3 Total Noncurrent Regulatory Liabilities 353.1 157.2 144.1 Total Regulatory Liabilities $ 375.3 $ 179.8 $ 175.4 March 31, September 30, March 31, Spire Missouri 2018 2017 2017 Regulatory Assets: Current: Pension and postretirement benefit costs $ 34.9 $ 34.9 $ 34.8 Unamortized purchased gas adjustments 13.5 57.4 17.1 Other 3.3 3.3 3.4 Total Current Regulatory Assets 51.7 95.6 55.3 Noncurrent: Future income taxes due from customers 111.4 170.5 159.7 Pension and postretirement benefit costs 279.0 322.7 358.3 Unamortized purchased gas adjustments — 9.9 1.1 Energy efficiency 31.3 29.0 27.0 Other 24.9 25.7 23.3 Total Noncurrent Regulatory Assets 446.6 557.8 569.4 Total Regulatory Assets $ 498.3 $ 653.4 $ 624.7 Regulatory Liabilities: Current: Other $ 2.7 $ 2.7 $ 2.7 Total Current Regulatory Liabilities 2.7 2.7 2.7 Noncurrent: Deferred taxes due to customers 152.6 — — Accrued cost of removal 48.7 54.5 55.6 Unamortized purchased gas adjustments 50.3 1.9 2.0 Other 20.9 24.8 26.9 Total Noncurrent Regulatory Liabilities 272.5 81.2 84.5 Total Regulatory Liabilities $ 275.2 $ 83.9 $ 87.2 March 31, September 30, March 31, Spire Alabama 2018 2017 2017 Regulatory Assets: Current: Pension and postretirement benefit costs $ 7.1 $ 7.2 $ 6.8 Unamortized purchased gas adjustments 19.0 45.2 43.9 Other 6.0 12.2 4.4 Total Current Regulatory Assets 32.1 64.6 55.1 Noncurrent: Pension and postretirement benefit costs 71.2 72.6 94.4 Cost of removal 125.0 123.3 133.9 Other 2.7 1.1 1.0 Total Noncurrent Regulatory Assets 198.9 197.0 229.3 Total Regulatory Assets $ 231.0 $ 261.6 $ 284.4 Regulatory Liabilities: Current: RSE adjustment $ — $ 1.4 $ 1.1 Unbilled service margin — — 13.5 Refundable negative salvage 5.3 8.2 8.1 Other 5.5 2.4 2.4 Total Current Regulatory Liabilities 10.8 12.0 25.1 Noncurrent: Pension and postretirement benefit costs 30.8 32.2 27.6 Refundable negative salvage 0.6 4.1 4.9 Other 3.6 3.3 3.4 Total Noncurrent Regulatory Liabilities 35.0 39.6 35.9 Total Regulatory Liabilities $ 45.8 $ 51.6 $ 61.0

FAIR VALUE OF FINANCIAL INSTR23

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	6 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair value of financial instruments	Classification of Estimated Fair Value Carrying Amount Fair Value Quoted Prices in Active Markets (Level 1) Significant Observable Inputs (Level 2) Spire As of March 31, 2018 Cash and cash equivalents $ 17.8 $ 17.8 $ 17.8 $ — Short-term debt 391.7 391.7 — 391.7 Long-term debt, including current portion 2,179.4 2,241.3 — 2,241.3 As of September 30, 2017 Cash and cash equivalents $ 7.4 $ 7.4 $ 7.4 $ — Short-term debt 477.3 477.3 — 477.3 Long-term debt, including current portion 2,095.0 2,210.3 — 2,210.3 As of March 31, 2017 Cash and cash equivalents $ 19.6 $ 19.6 $ 19.6 $ — Short-term debt 567.4 567.4 — 567.4 Long-term debt 1,925.3 1,993.9 — 1,993.9 Spire Missouri As of March 31, 2018 Cash and cash equivalents $ 10.2 $ 10.2 $ 10.2 $ — Short-term debt 175.8 175.8 — 175.8 Long-term debt, including current portion 974.0 1,033.6 — 1,033.6 As of September 30, 2017 Cash and cash equivalents $ 2.5 $ 2.5 $ 2.5 $ — Short-term debt 203.0 203.0 — 203.0 Long-term debt, including current portion 973.9 1,056.9 — 1,056.9 As of March 31, 2017 Cash and cash equivalents $ 3.7 $ 3.7 $ 3.7 $ — Short-term debt 282.2 282.2 — 282.2 Long-term debt 804.3 870.1 — 870.1 Spire Alabama As of March 31, 2018 Short-term debt $ 82.3 $ 82.3 $ — $ 82.3 Long-term debt 322.5 332.7 — 332.7 As of September 30, 2017 Cash and cash equivalents $ 0.1 $ 0.1 $ 0.1 $ — Short-term debt 169.9 169.9 — 169.9 Long-term debt 247.8 269.4 — 269.4 As of March 31, 2017 Short-term debt $ 109.3 $ 109.3 $ — $ 109.3 Long-term debt 247.7 261.6 — 261.6

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	6 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value Measurements, Measured on Recurring Basis	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 March 31, 2018 ASSETS US stock/bond mutual funds $ 19.1 $ 4.1 $ — $ — $ 23.2 NYMEX/ICE natural gas contracts 0.1 — — (0.1 ) — Total $ 19.2 $ 4.1 $ — $ (0.1 ) $ 23.2 LIABILITIES NYMEX/ICE natural gas contracts $ 0.2 $ — $ — $ (0.2 ) $ — Total $ 0.2 $ — $ — $ (0.2 ) $ — As of September 30, 2017 ASSETS US stock/bond mutual funds $ 18.3 $ 4.1 $ — $ — $ 22.4 NYMEX/ICE natural gas contracts 3.4 — — (3.4 ) — NYMEX gasoline and heating oil contracts 0.1 — — — 0.1 Total $ 21.8 $ 4.1 $ — $ (3.4 ) $ 22.5 LIABILITIES NYMEX/ICE natural gas contracts $ 1.9 $ — $ — $ (1.9 ) $ — Total $ 1.9 $ — $ — $ (1.9 ) $ — As of March 31, 2017 ASSETS US stock/bond mutual funds $ 17.7 $ 4.1 $ — $ — $ 21.8 NYMEX/ICE natural gas contracts 4.5 — — (1.8 ) 2.7 NYMEX gasoline and heating oil contracts 0.2 — — — 0.2 Total $ 22.4 $ 4.1 $ — $ (1.8 ) $ 24.7 LIABILITIES NYMEX/ICE natural gas contracts $ 0.5 $ — $ — $ (0.5 ) $ — Total $ 0.5 $ — $ — $ (0.5 ) $ — 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 March 31, 2018 ASSETS Gas Utility: US stock/bond mutual funds $ 19.1 $ 4.1 $ — $ — $ 23.2 NYMEX/ICE natural gas contracts 0.1 — — (0.1 ) — Gas Marketing: NYMEX/ICE natural gas contracts 0.2 3.3 — (3.5 ) — Natural gas commodity contracts — 7.4 0.1 (2.1 ) 5.4 Other: Interest rate swaps — 1.0 — — 1.0 Total $ 19.4 $ 15.8 $ 0.1 $ (5.7 ) $ 29.6 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 0.2 $ — $ — $ (0.2 ) $ — Gas Marketing: NYMEX/ICE natural gas contracts 0.6 9.8 — (10.4 ) — Natural gas commodity contracts — 14.3 — (2.1 ) 12.2 Total $ 0.8 $ 24.1 $ — $ (12.7 ) $ 12.2 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, 2017 ASSETS Gas Utility: US stock/bond mutual funds $ 18.3 $ 4.1 $ — $ — $ 22.4 NYMEX/ICE natural gas contracts 3.4 — — (3.4 ) — NYMEX gasoline and heating oil contracts 0.1 — — — 0.1 Gas Marketing: NYMEX/ICE natural gas contracts 1.3 1.3 — (2.1 ) 0.5 Natural gas commodity contracts — 6.8 0.1 (1.2 ) 5.7 Total $ 23.1 $ 12.2 $ 0.1 $ (6.7 ) $ 28.7 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 1.9 $ — $ — $ (1.9 ) $ — Gas Marketing: NYMEX/ICE natural gas contracts 1.8 0.3 — (2.1 ) — Natural gas commodity contracts — 8.4 — (1.2 ) 7.2 Other: Interest rate swaps — 0.9 — — 0.9 Total $ 3.7 $ 9.6 $ — $ (5.2 ) $ 8.1 As of March 31, 2017 ASSETS Gas Utility: US stock/bond mutual funds $ 17.7 $ 4.1 $ — $ — $ 21.8 NYMEX/ICE natural gas contracts 4.5 — — (1.8 ) 2.7 NYMEX gasoline and heating oil contracts 0.2 — — — 0.2 Gas Marketing: NYMEX/ICE natural gas contracts 1.0 3.6 — (4.4 ) 0.2 Natural gas commodity contracts — 6.2 0.2 (0.5 ) 5.9 Other: Interest rate swaps — 0.2 — — 0.2 Total $ 23.4 $ 14.1 $ 0.2 $ (6.7 ) $ 31.0 LIABILITIES Gas Utility: NYMEX/ICE natural gas contracts $ 0.5 $ — $ — $ (0.5 ) $ — Gas Marketing: NYMEX/ICE natural gas contracts 2.1 3.9 — (6.0 ) — Natural gas commodity contracts — 6.5 — (0.5 ) 6.0 Total $ 2.6 $ 10.4 $ — $ (7.0 ) $ 6.0

PENSION PLANS AND OTHER POSTR25

PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS (Tables)	6 Months Ended
	Mar. 31, 2018
Defined Contribution Plan [Abstract]
Schedule of Net Periodic Cost	Net periodic postretirement benefit costs consisted of the following components: Three Months Ended March 31, Six Months Ended March 31, 2018 2017 2018 2017 Spire Service cost – benefits earned during the period $ 2.4 $ 2.7 $ 4.7 $ 5.5 Interest cost on accumulated postretirement benefit obligation 2.2 2.2 4.4 4.3 Expected return on plan assets (3.5 ) (3.4 ) (7.0 ) (6.8 ) Amortization of prior service credit (0.1 ) — (0.1 ) — Amortization of actuarial loss 0.2 0.6 0.4 1.2 Subtotal 1.2 2.1 2.4 4.2 Regulatory adjustment — (0.8 ) 0.1 (1.6 ) Net postretirement benefit cost $ 1.2 $ 1.3 $ 2.5 $ 2.6 Spire Missouri Service cost – benefits earned during the period $ 2.3 $ 2.6 $ 4.5 $ 5.2 Interest cost on accumulated postretirement benefit obligation 1.8 1.7 3.6 3.4 Expected return on plan assets (2.5 ) (2.2 ) (4.9 ) (4.5 ) Amortization of prior service cost — — 0.1 0.1 Amortization of actuarial loss 0.2 0.7 0.4 1.3 Subtotal 1.8 2.8 3.7 5.5 Regulatory adjustment 0.5 (0.3 ) 1.0 (0.7 ) Net postretirement benefit cost $ 2.3 $ 2.5 $ 4.7 $ 4.8 Spire Alabama Service cost – benefits earned during the period $ 0.1 $ 0.1 $ 0.1 $ 0.2 Interest cost on accumulated postretirement benefit obligation 0.3 0.4 0.7 0.8 Expected return on plan assets (1.0 ) (1.1 ) (2.0 ) (2.2 ) Amortization of prior service credit (0.1 ) — (0.2 ) (0.1 ) Amortization of actuarial gain — (0.1 ) — (0.1 ) Subtotal (0.7 ) (0.7 ) (1.4 ) (1.4 ) Regulatory adjustment (0.5 ) (0.5 ) (0.9 ) (0.9 ) Net postretirement benefit income $ (1.2 ) $ (1.2 ) $ (2.3 ) $ (2.3 ) The net periodic pension cost included the following components: Three Months Ended March 31, Six Months Ended March 31, 2018 2017 2018 2017 Spire Service cost – benefits earned during the period $ 5.2 $ 5.2 $ 10.4 $ 10.5 Interest cost on projected benefit obligation 6.9 6.9 13.8 13.8 Expected return on plan assets (9.5 ) (9.7 ) (19.2 ) (19.6 ) Amortization of prior service (credit) cost (0.2 ) 0.3 (0.5 ) 0.5 Amortization of actuarial loss 2.9 3.2 6.0 6.6 Loss on lump-sum settlements 9.4 11.9 9.4 11.9 Subtotal 14.7 17.8 19.9 23.7 Regulatory adjustment 24.0 (7.4 ) 28.3 (2.8 ) Net pension cost $ 38.7 $ 10.4 $ 48.2 $ 20.9 Spire Missouri Service cost – benefits earned during the period $ 3.2 $ 3.3 $ 6.5 $ 6.6 Interest cost on projected benefit obligation 4.9 4.9 9.8 9.7 Expected return on plan assets (7.0 ) (7.1 ) (14.2 ) (14.4 ) Amortization of prior service cost 0.2 0.3 0.4 0.5 Amortization of actuarial loss 2.5 2.8 5.1 5.7 Loss on lump-sum settlements 9.4 11.5 9.4 11.5 Subtotal 13.2 15.7 17.0 19.6 Regulatory adjustment 21.9 (8.6 ) 24.3 (5.8 ) Net pension cost $ 35.1 $ 7.1 $ 41.3 $ 13.8 Spire Alabama Service cost – benefits earned during the period $ 1.7 $ 1.5 $ 3.3 $ 3.1 Interest cost on projected benefit obligation 1.4 1.5 2.8 3.0 Expected return on plan assets (1.7 ) (1.8 ) (3.4 ) (3.6 ) Amortization of prior service credit (0.4 ) — (0.9 ) — Amortization of actuarial loss 0.4 0.4 0.9 0.9 Loss on lump-sum settlements — 0.4 — 0.4 Subtotal 1.4 2.0 2.7 3.8 Regulatory adjustment 1.9 1.1 3.6 2.7 Net pension cost $ 3.3 $ 3.1 $ 6.3 $ 6.5

INFORMATION BY OPERATING SEGM26

INFORMATION BY OPERATING SEGMENT (Tables)	6 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Schedule of operating segment information	Gas Utility Gas Marketing Other Eliminations Consolidated Three Months Ended March 31, 2018 Operating Revenues: Revenues from external customers $ 790.6 $ 21.3 $ 1.5 $ — $ 813.4 Intersegment revenues 0.2 — 2.9 (3.1 ) — Total Operating Revenues 790.8 21.3 4.4 (3.1 ) 813.4 Operating Expenses: Gas Utility Natural and propane gas 403.2 — — (19.5 ) 383.7 Operation and maintenance 145.8 — — (2.2 ) 143.6 Depreciation and amortization 41.1 — — — 41.1 Taxes, other than income taxes 58.0 — — — 58.0 Total Gas Utility Operating Expenses 648.1 — — (21.7 ) 626.4 Gas Marketing and Other — 20.2 6.4 18.6 45.2 Total Operating Expenses 648.1 20.2 6.4 (3.1 ) 671.6 Operating Income (Loss) $ 142.7 $ 1.1 $ (2.0 ) $ — $ 141.8 Net Economic Earnings (Loss) $ 131.7 $ 10.2 $ (4.7 ) $ — $ 137.2 Gas Utility Gas Marketing Other Eliminations Consolidated Three Months Ended March 31, 2017 Operating Revenues: Revenues from external customers $ 641.1 $ 22.2 $ 0.1 $ — $ 663.4 Intersegment revenues 2.6 — 1.7 (4.3 ) — Total Operating Revenues 643.7 22.2 1.8 (4.3 ) 663.4 Operating Expenses: Gas Utility Natural and propane gas 275.6 — — (21.3 ) 254.3 Operation and maintenance 99.3 — — (0.9 ) 98.4 Depreciation and amortization 37.9 — — — 37.9 Taxes, other than income taxes 48.3 — — — 48.3 Total Gas Utility Operating Expenses 461.1 — — (22.2 ) 438.9 Gas Marketing and Other — 23.9 2.3 17.9 44.1 Total Operating Expenses 461.1 23.9 2.3 (4.3 ) 483.0 Operating Income (Loss) $ 182.6 $ (1.7 ) $ (0.5 ) $ — $ 180.4 Net Economic Earnings (Loss) $ 112.2 $ — $ (3.2 ) $ — $ 109.0 Gas Utility Gas Marketing Other Eliminations Consolidated Six Months Ended March 31, 2018 Operating Revenues: Revenues from external customers $ 1,332.5 $ 40.9 $ 1.8 $ — $ 1,375.2 Intersegment revenues 0.3 — 5.4 (5.7 ) — Total Operating Revenues 1,332.8 40.9 7.2 (5.7 ) 1,375.2 Operating Expenses: Gas Utility Natural and propane gas 666.6 — — (42.1 ) 624.5 Operation and maintenance 245.6 — — (4.1 ) 241.5 Depreciation and amortization 81.4 — — — 81.4 Taxes, other than income taxes 94.7 — — — 94.7 Total Gas Utility Operating Expenses 1,088.3 — — (46.2 ) 1,042.1 Gas Marketing and Other — 34.8 10.9 40.5 86.2 Total Operating Expenses 1,088.3 34.8 10.9 (5.7 ) 1,128.3 Operating Income (Loss) $ 244.5 $ 6.1 $ (3.7 ) $ — $ 246.9 Net Economic Earnings (Loss) $ 191.2 $ 13.8 $ (9.9 ) $ — $ 195.1 Six Months Ended March 31, 2017 Operating Revenues: Revenues from external customers $ 1,113.4 $ 43.9 $ 1.2 $ — $ 1,158.5 Intersegment revenues 7.0 — 2.4 (9.4 ) — Total Operating Revenues 1,120.4 43.9 3.6 (9.4 ) 1,158.5 Operating Expenses: Gas Utility Natural and propane gas 490.1 — — (42.0 ) 448.1 Operation and maintenance 199.8 — — (2.0 ) 197.8 Depreciation and amortization 75.6 — — — 75.6 Taxes, other than income taxes 81.7 — — — 81.7 Total Gas Utility Operating Expenses 847.2 — — (44.0 ) 803.2 Gas Marketing and Other — 46.9 4.3 34.6 85.8 Total Operating Expenses 847.2 46.9 4.3 (9.4 ) 889.0 Operating Income (Loss) $ 273.2 $ (3.0 ) $ (0.7 ) $ — $ 269.5 Net Economic Earnings (Loss) $ 164.0 $ 1.4 $ (8.9 ) $ — $ 156.5 The Company’s total assets by segment were as follows: March 31, September 30, March 31, 2018 2017 2017 Total Assets: Gas Utility $ 5,484.3 $ 5,551.2 $ 5,290.8 Gas Marketing 208.6 246.2 218.2 Other 2,211.9 2,239.5 2,199.1 Eliminations (1,318.0 ) (1,490.2 ) (1,451.4 ) Total Assets $ 6,586.8 $ 6,546.7 $ 6,256.7
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 March 31, Six Months Ended March 31, 2018 2017 2018 2017 Net Income $ 98.2 $ 108.0 $ 214.2 $ 153.2 Adjustments, pre-tax: Missouri regulatory adjustments 30.6 — 30.6 — Unrealized loss on energy-related derivative contracts 11.8 1.6 12.6 5.4 Lower of cost or market inventory adjustments — 0.1 — — Realized gain on economic hedges prior to sale of the physical commodity (0.2 ) (0.1 ) (0.3 ) (0.2 ) Acquisition, divestiture and restructuring activities 2.0 0.1 3.7 0.2 Income tax effect of adjustments (11.1 ) (0.7 ) (11.7 ) (2.1 ) Effects of the Tax Cuts and Jobs Act 5.9 — (54.0 ) — Net Economic Earnings $ 137.2 $ 109.0 $ 195.1 $ 156.5

INCOME TAXES (Tables)

INCOME TAXES (Tables)	6 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Summary of Impact of Tax Cuts and Jobs Act	The updated total amounts recorded, which had no impact on cash flows for the six months ended March 31, 2018, are presented in the table below. Spire Spire Missouri Spire Alabama Adjustment to deferred tax assets $ — $ — $ (60.8 ) Adjustment to deferred tax liabilities (299.5 ) (268.2 ) — Adjustment to deferred income tax expense (69.4 ) (54.6 ) 59.2 Adjustment to regulatory assets (59.4 ) (61.0 ) 1.6 Adjustment to regulatory liabilities 170.7 152.6 —

SUMMARY OF SIGNIFICANT ACCOUN28

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Millions	Dec. 31, 2017USD ($)	Mar. 31, 2018USD ($)reporting_unit	Sep. 30, 2017USD ($)	Mar. 31, 2017USD ($)
Related Party Transaction [Line Items]
Number of operating segments | reporting_unit		2
Spire Missouri
Related Party Transaction [Line Items]
Accrued unbilled revenues		$ 85.2	$ 30.1	$ 66.7
Spire Alabama
Related Party Transaction [Line Items]
Accrued unbilled revenues		$ 5.3	$ 1.9	$ 13.5
Ryckman Creek Resources, LLC
Related Party Transaction [Line Items]
Voting interest acquired	80.00%
Purchase price of acquisition	$ 24.8
Cash paid for acquisition	16
Promissory note for acquisition	10
Promissory note, value	$ 8.8

SUMMARY OF SIGNIFICANT ACCOUN29

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Gross Receipts Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Schedule of Gross Receipts Taxes [Line Items]
Gross Receipts taxes recorded in regulated gas distribution operating revenues	$ 43.6	$ 34.3	$ 66.7	$ 53.7
Spire Missouri
Schedule of Gross Receipts Taxes [Line Items]
Gross Receipts taxes recorded in regulated gas distribution operating revenues	30.6	25.5	46.8	39.6
Spire Alabama
Schedule of Gross Receipts Taxes [Line Items]
Gross Receipts taxes recorded in regulated gas distribution operating revenues	$ 11.6	$ 7.7	$ 17.2	$ 11.9

SUMMARY OF SIGNIFICANT ACCOUN30

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Inter-company Transactions (Details) - Affiliated Entity - Spire Missouri - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Spire Marketing | Regulated Operation
Related Party Transaction [Line Items]
Purchases of natural gas from Spire Marketing	$ 19.3	$ 21	$ 41.6	$ 41.5
Sales of natural gas to Spire Marketing	0.2	2.7	0.3	6.3
Spire NGL Inc. | Unregulated Operation
Related Party Transaction [Line Items]
Transportation services received from Spire NGL Inc.	$ 0.2	$ 0.2	$ 0.5	$ 0.5

SUMMARY OF SIGNIFICANT ACCOUN31

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Capital Expenditure Excluded from Statement of Cash Flow (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Sep. 30, 2016
Schedule of Accrued Capital Expenditures Excluded from Statement of Cash Flow [Line Items]
Accrued capital expenditures	$ 29.1	$ 9.2	$ 41
Spire Missouri
Schedule of Accrued Capital Expenditures Excluded from Statement of Cash Flow [Line Items]
Accrued capital expenditures	17.9	3.3	28.9
Spire Alabama
Schedule of Accrued Capital Expenditures Excluded from Statement of Cash Flow [Line Items]
Accrued capital expenditures	$ 7	$ 5.3	$ 9.4

EARNINGS PER COMMON SHARE (Deta

EARNINGS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Basic Earnings Per Share:
Net Income	$ 98.2	$ 108	$ 214.2	$ 153.2
Less: Income allocated to participating securities	0.2	0.2	0.5	0.4
Net Income Available to Common Shareholders	$ 98	$ 107.8	$ 213.7	$ 152.8
Weighted Average Shares Outstanding (in Shares)	48.2	45.6	48.2	45.6
Basic Earnings Per Share of Common Stock (in dollars per share)	$ 2.03	$ 2.36	$ 4.43	$ 3.35
Diluted Earnings Per Share:
Net Income	$ 98.2	$ 108	$ 214.2	$ 153.2
Less: Income allocated to participating securities	0.2	0.2	0.5	0.4
Net Income Available to Common Shareholders	$ 98	$ 107.8	$ 213.7	$ 152.8
Weighted Average Shares Outstanding (in Shares)	48.2	45.6	48.2	45.6
Dilutive Effect of Restricted Stock and Restricted Stock Units (in shares)	0.2	0.1	0.2	0.1
Weighted Average Diluted Shares (in shares)	48.4	45.7	48.4	45.7
Diluted Earnings Per Share of Common Stock (in dollars per share)	$ 2.03	$ 2.36	$ 4.42	$ 3.34
Restricted stock and stock units subject to performance and/or market conditions
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding shares excluded from calculation of diluted EPS (in shares)	0.4	0.5	0.4	0.5

REGULATORY MATTERS - Schedule o

REGULATORY MATTERS - Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2018	Sep. 30, 2017	Mar. 31, 2017
Regulatory Assets [Line Items]
Regulatory Assets: Non-current	$ 673.6	$ 791.1	$ 827.7
Total Regulatory Assets	771.3	966.6	953.5
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Non-current	353.1	157.2	144.1
Total Regulatory Liabilities	375.3	179.8	175.4
Rate Stabilization and Equalization (RSE) adjustment
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Current	0	1.4	1.1
Unbilled service margin
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Current	0	0	13.5
Deferred taxes due to customers
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Non-current	170.7	0	0
Pension and postretirement benefit costs
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Non-current	30.8	32.2	27.6
Refundable negative salvage
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Current	5.3	8.2	8.1
Regulatory Liabilities: Non-current	0.6	4.1	4.9
Accrued cost of removal
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Non-current	71	83.8	75.3
Unamortized purchased gas adjustments
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Current	1.5	1	1.6
Regulatory Liabilities: Non-current	50.3	1.9	2
Other
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Current	15.4	12	7
Regulatory Liabilities: Non-current	29.7	35.2	34.3
Total Regulatory Liabilities (current)
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Current	22.2	22.6	31.3
Total Regulatory Liabilities (non-current)
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Non-current	353.1	157.2	144.1
Future income taxes due from customers
Regulatory Assets [Line Items]
Regulatory Assets: Non-current	113	170.5	159.7
Pension and postretirement benefit costs
Regulatory Assets [Line Items]
Regulatory Assets: Current	43	42.2	41.7
Regulatory Assets: Non-current	358.2	404.7	461.8
Accrued cost of removal
Regulatory Assets [Line Items]
Regulatory Assets: Non-current	125	123.3	133.9
Unamortized purchased gas adjustments
Regulatory Assets [Line Items]
Regulatory Assets: Current	32.6	102.6	61
Regulatory Assets: Non-current	0	9.9	1.1
Energy efficiency
Regulatory Assets [Line Items]
Regulatory Assets: Non-current	31.3	29	27
Other
Regulatory Assets [Line Items]
Regulatory Assets: Current	22.1	30.7	23.1
Regulatory Assets: Non-current	46.1	53.7	44.2
Total Current Regulatory Assets
Regulatory Assets [Line Items]
Regulatory Assets: Current	97.7	175.5	125.8
Total Noncurrent Regulatory Assets
Regulatory Assets [Line Items]
Regulatory Assets: Non-current	673.6	791.1	827.7
Spire Missouri
Regulatory Assets [Line Items]
Regulatory Assets: Non-current	446.6	557.8	569.4
Total Regulatory Assets	498.3	653.4	624.7
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Non-current	272.5	81.2	84.5
Total Regulatory Liabilities	275.2	83.9	87.2
Spire Missouri | Deferred taxes due to customers
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Non-current	152.6	0	0
Spire Missouri | Accrued cost of removal
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Non-current	48.7	54.5	55.6
Spire Missouri | Unamortized purchased gas adjustments
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Non-current	50.3	1.9	2
Spire Missouri | Other
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Current	2.7	2.7	2.7
Regulatory Liabilities: Non-current	20.9	24.8	26.9
Spire Missouri | Total Regulatory Liabilities (current)
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Current	2.7	2.7	2.7
Spire Missouri | Total Regulatory Liabilities (non-current)
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Non-current	272.5	81.2	84.5
Spire Missouri | Future income taxes due from customers
Regulatory Assets [Line Items]
Regulatory Assets: Non-current	111.4	170.5	159.7
Spire Missouri | Pension and postretirement benefit costs
Regulatory Assets [Line Items]
Regulatory Assets: Current	34.9	34.9	34.8
Regulatory Assets: Non-current	279	322.7	358.3
Spire Missouri | Unamortized purchased gas adjustments
Regulatory Assets [Line Items]
Regulatory Assets: Current	13.5	57.4	17.1
Regulatory Assets: Non-current	0	9.9	1.1
Spire Missouri | Energy efficiency
Regulatory Assets [Line Items]
Regulatory Assets: Non-current	31.3	29	27
Spire Missouri | Other
Regulatory Assets [Line Items]
Regulatory Assets: Current	3.3	3.3	3.4
Regulatory Assets: Non-current	24.9	25.7	23.3
Spire Missouri | Total Current Regulatory Assets
Regulatory Assets [Line Items]
Regulatory Assets: Current	51.7	95.6	55.3
Spire Missouri | Total Noncurrent Regulatory Assets
Regulatory Assets [Line Items]
Regulatory Assets: Non-current	446.6	557.8	569.4
Spire Alabama
Regulatory Assets [Line Items]
Regulatory Assets: Non-current	198.9	197	229.3
Total Regulatory Assets	231	261.6	284.4
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Non-current	35	39.6	35.9
Total Regulatory Liabilities	45.8	51.6	61
Spire Alabama | Rate Stabilization and Equalization (RSE) adjustment
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Current	0	1.4	1.1
Spire Alabama | Unbilled service margin
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Current	0	0	13.5
Spire Alabama | Pension and postretirement benefit costs
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Non-current	30.8	32.2	27.6
Spire Alabama | Refundable negative salvage
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Current	5.3	8.2	8.1
Regulatory Liabilities: Non-current	0.6	4.1	4.9
Spire Alabama | Other
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Current	5.5	2.4	2.4
Regulatory Liabilities: Non-current	3.6	3.3	3.4
Spire Alabama | Total Regulatory Liabilities (current)
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Current	10.8	12	25.1
Spire Alabama | Total Regulatory Liabilities (non-current)
Regulatory Liabilities [Line Items]
Regulatory Liabilities: Non-current	35	39.6	35.9
Spire Alabama | Pension and postretirement benefit costs
Regulatory Assets [Line Items]
Regulatory Assets: Current	7.1	7.2	6.8
Regulatory Assets: Non-current	71.2	72.6	94.4
Spire Alabama | Accrued cost of removal
Regulatory Assets [Line Items]
Regulatory Assets: Non-current	125	123.3	133.9
Spire Alabama | Unamortized purchased gas adjustments
Regulatory Assets [Line Items]
Regulatory Assets: Current	19	45.2	43.9
Spire Alabama | Other
Regulatory Assets [Line Items]
Regulatory Assets: Current	6	12.2	4.4
Regulatory Assets: Non-current	2.7	1.1	1
Spire Alabama | Total Current Regulatory Assets
Regulatory Assets [Line Items]
Regulatory Assets: Current	32.1	64.6	55.1
Spire Alabama | Total Noncurrent Regulatory Assets
Regulatory Assets [Line Items]
Regulatory Assets: Non-current	$ 198.9	$ 197	$ 229.3

REGULATORY MATTERS - Schedule34

REGULATORY MATTERS - Schedule of Regulatory Assets Not Earnings a Return (Details) - USD ($) $ in Millions	Mar. 31, 2018	Sep. 30, 2017	Mar. 31, 2017
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	$ 309.8	$ 380.3	$ 412.5
Future income taxes due from customers
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	113	170.5	159.7
Pension and postretirement benefit costs
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	185.8	198.5	241
Other
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	11	11.3	11.8
Spire Missouri
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	308.2	380.3	412.5
Spire Missouri | Future income taxes due from customers
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	111.4	170.5	159.7
Spire Missouri | Pension and postretirement benefit costs
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	185.8	198.5	241
Spire Missouri | Other
Regulatory Assets [Line Items]
Total Regulatory Assets Not Earning a Return	$ 11	$ 11.3	$ 11.8

REGULATORY MATTERS - Narrative

REGULATORY MATTERS - Narrative (Details) - USD ($)	Mar. 07, 2018	Apr. 11, 2017	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Sep. 30, 2017
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
Effects of the Tax Cuts and Jobs Act	$ 33,000,000		$ 5,900,000	$ 0	$ (54,000,000)	$ 0
Regulatory asset			771,300,000	$ 953,500,000	$ 771,300,000	$ 953,500,000	$ 966,600,000
Pension and postretirement benefit costs | Spire Missouri East
Public Utilities, General Disclosures [Line Items]
Remaining recovery period for regulatory assets for which no return on investment during recovery period is provided (in years)					8 years
Amortization of regulatory assets not earning a return					$ 173,000,000
Pension and postretirement benefit costs | Spire Missouri West
Public Utilities, General Disclosures [Line Items]
Amortization of regulatory assets not earning a return					26,200,000
ISRS surcharge | MoPSC
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount	0
Approved rate increase (decrease), incentive compensation costs excluded from rate base	6,900,000
Approved rate increase (decrease), incentive compensation costs from buildings sold in 2014 excluded from rate base	1,800,000
Approved rate increase (decrease), rate case expenses excluded from rate base	900,000
Approved rate increase (decrease), regulatory charges			$ 38,400,000		$ 38,400,000
Approved rate increase (decrease), impact to net income (loss)	$ 23,600,000
Approved rate increase (decrease), impact to earnings per share (in usd per share)	$ 0.49
ISRS surcharge | MoPSC | Spire Missouri East
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount	$ 18,000,000	$ 32,600,000
Approved rate increase (decrease), annualized revenue	(14,600,000)
ISRS surcharge | MoPSC | Spire Missouri West
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount	15,200,000	16,400,000
Approved rate increase (decrease), annualized revenue	(1,200,000)
ISRS surcharge | MoPSC | Pension costs
Public Utilities, General Disclosures [Line Items]
Increase (decrease) in regulatory assets	(28,800,000)
Approved rate increase (decrease), regulatory charges	30,600,000
ISRS surcharge | MoPSC | Pension costs | Spire Missouri East
Public Utilities, General Disclosures [Line Items]
Regulatory asset	29,000,000	15,500,000
ISRS surcharge | MoPSC | Pension costs | Spire Missouri West
Public Utilities, General Disclosures [Line Items]
Regulatory asset	5,500,000	9,900,000
ISRS surcharge | MoPSC | Postretirement health care costs | Spire Missouri East
Public Utilities, General Disclosures [Line Items]
Regulatory asset	$ 8,600,000	$ 9,500,000

FINANCING ARRANGEMENTS AND LO36

FINANCING ARRANGEMENTS AND LONG-TERM DEBT (Details)	Dec. 21, 2016USD ($)	Dec. 14, 2016USD ($)bank	Mar. 31, 2018USD ($)	Jan. 12, 2018USD ($)	Dec. 01, 2017USD ($)	Sep. 30, 2017USD ($)	Mar. 31, 2017USD ($)
Line of Credit Facility [Line Items]
Debt covenant, short-term debt to capital requirement, maximum		70.00%
Notes outstanding			$ 391,700,000			$ 477,300,000	$ 567,400,000
Commercial Paper Notes
Line of Credit Facility [Line Items]
Face amount	$ 975,000,000
Debt term	365 days
Spire Missouri
Line of Credit Facility [Line Items]
Notes outstanding			175,800,000
Spire Alabama
Line of Credit Facility [Line Items]
Notes outstanding			$ 82,300,000
Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Number of banks in loan agreement | bank		11
Maximum borrowing capacity		$ 975,000,000
Line of Credit | Revolving Credit Facility | Spire Missouri
Line of Credit Facility [Line Items]
Maximum borrowing capacity		475,000,000
Ratio of short-term debt to total capital			0.48
Line of Credit | Revolving Credit Facility | Spire Alabama
Line of Credit Facility [Line Items]
Maximum borrowing capacity		200,000,000
Ratio of short-term debt to total capital			0.33
Line of Credit | Revolving Credit Facility | Spire
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 300,000,000
Ratio of short-term debt to total capital			0.54
Credit facility borrowings			$ 0			$ 0	$ 0
Senior Notes | Spire Alabama | Series 2017A senior notes due 2058
Line of Credit Facility [Line Items]
Face amount					$ 30,000,000
Stated interest rate					4.02%
Senior Notes | Spire Alabama | Series 2017B senior notes due 2048
Line of Credit Facility [Line Items]
Face amount				$ 45,000,000
Stated interest rate				3.92%

FAIR VALUE OF FINANCIAL INSTR37

FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Millions	Mar. 31, 2018	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 17.8	$ 7.4	$ 19.6	$ 5.2
Spire Missouri
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	10.2	2.5	3.7	2.1
Spire Alabama
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0.1	0	$ 0
Quoted Prices in Active Markets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	17.8	7.4	19.6
Short-term debt	0	0	0
Long-term debt, including current portion	0	0	0
Quoted Prices in Active Markets (Level 1) | Spire Missouri
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	10.2	2.5	3.7
Short-term debt	0	0	0
Long-term debt, including current portion	0	0	0
Quoted Prices in Active Markets (Level 1) | Spire Alabama
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents		0.1
Short-term debt	0	0	0
Long-term debt, including current portion	0	0	0
Significant Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0	0
Short-term debt	391.7	477.3	567.4
Long-term debt, including current portion	2,241.3	2,210.3	1,993.9
Significant Observable Inputs (Level 2) | Spire Missouri
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0	0
Short-term debt	175.8	203	282.2
Long-term debt, including current portion	1,033.6	1,056.9	870.1
Significant Observable Inputs (Level 2) | Spire Alabama
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents		0
Short-term debt	82.3	169.9	109.3
Long-term debt, including current portion	332.7	269.4	261.6
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	17.8	7.4	19.6
Short-term debt	391.7	477.3	567.4
Long-term debt, including current portion	2,179.4	2,095	1,925.3
Carrying Amount | Spire Missouri
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	10.2	2.5	3.7
Short-term debt	175.8	203	282.2
Long-term debt, including current portion	974	973.9	804.3
Carrying Amount | Spire Alabama
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents		0.1
Short-term debt	82.3	169.9	109.3
Long-term debt, including current portion	322.5	247.8	247.7
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	17.8	7.4	19.6
Short-term debt	391.7	477.3	567.4
Long-term debt, including current portion	2,241.3	2,210.3	1,993.9
Fair Value | Spire Missouri
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	10.2	2.5	3.7
Short-term debt	175.8	203	282.2
Long-term debt, including current portion	1,033.6	1,056.9	870.1
Fair Value | Spire Alabama
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents		0.1
Short-term debt	82.3	169.9	109.3
Long-term debt, including current portion	$ 332.7	$ 269.4	$ 261.6

FAIR VALUE MEASUREMENTS (Detail

FAIR VALUE MEASUREMENTS (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions	Mar. 31, 2018	Sep. 30, 2017	Mar. 31, 2017
ASSETS
Effects of Netting and Cash Margin Receivables /Payables	$ (5.7)		$ (6.7)
Derivative asset	29.6		31
LIABILITIES
Effects of Netting and Cash Margin Receivables /Payables	(12.7)	$ (5.2)	(7)
Derivative liability	12.2	8.1	6
Spire Missouri
ASSETS
Effects of Netting and Cash Margin Receivables /Payables	(0.1)	(3.4)	(1.8)
Derivative asset	23.2	22.5	24.7
LIABILITIES
Effects of Netting and Cash Margin Receivables /Payables	(0.2)	(1.9)	(0.5)
Derivative liability	0	0	0
Quoted Prices in Active Markets (Level 1)
ASSETS
Derivative asset before netting adjustment	19.4		23.4
LIABILITIES
Derivative liability before netting adjustment	0.8	3.7	2.6
Quoted Prices in Active Markets (Level 1) | Spire Missouri
ASSETS
Derivative asset before netting adjustment	19.2	21.8	22.4
LIABILITIES
Derivative liability before netting adjustment	0.2	1.9	0.5
Significant Observable Inputs (Level 2)
ASSETS
Derivative asset before netting adjustment	15.8		14.1
LIABILITIES
Derivative liability before netting adjustment	24.1	9.6	10.4
Significant Observable Inputs (Level 2) | Spire Missouri
ASSETS
Derivative asset before netting adjustment	4.1	4.1	4.1
LIABILITIES
Derivative liability before netting adjustment	0	0	0
Significant Unobservable Inputs (Level 3)
ASSETS
Derivative asset before netting adjustment	0.1		0.2
LIABILITIES
Derivative liability before netting adjustment	0	0	0
Significant Unobservable Inputs (Level 3) | Spire Missouri
ASSETS
Derivative asset before netting adjustment	0	0	0
LIABILITIES
Derivative liability before netting adjustment	0	0	0
US stock/bond mutual funds | Spire Missouri
ASSETS
Effects of Netting and Cash Margin Receivables /Payables	0	0	0
Derivative asset	23.2	22.4	21.8
US stock/bond mutual funds | Quoted Prices in Active Markets (Level 1) | Spire Missouri
ASSETS
Derivative asset before netting adjustment	19.1	18.3	17.7
US stock/bond mutual funds | Significant Observable Inputs (Level 2) | Spire Missouri
ASSETS
Derivative asset before netting adjustment	4.1	4.1	4.1
US stock/bond mutual funds | Significant Unobservable Inputs (Level 3) | Spire Missouri
ASSETS
Derivative asset before netting adjustment	0	0	0
NYMEX/ICE natural gas contracts | Spire Missouri
ASSETS
Effects of Netting and Cash Margin Receivables /Payables	(0.1)	(3.4)	(1.8)
Derivative asset	0	0	2.7
LIABILITIES
Effects of Netting and Cash Margin Receivables /Payables	(0.2)	(1.9)	(0.5)
Derivative liability	0	0	0
NYMEX/ICE natural gas contracts | Quoted Prices in Active Markets (Level 1) | Spire Missouri
ASSETS
Derivative asset before netting adjustment	0.1	3.4	4.5
LIABILITIES
Derivative liability before netting adjustment	0.2	1.9	0.5
NYMEX/ICE natural gas contracts | Significant Observable Inputs (Level 2) | Spire Missouri
ASSETS
Derivative asset before netting adjustment	0	0	0
LIABILITIES
Derivative liability before netting adjustment	0	0	0
NYMEX/ICE natural gas contracts | Significant Unobservable Inputs (Level 3) | Spire Missouri
ASSETS
Derivative asset before netting adjustment	0	0	0
LIABILITIES
Derivative liability before netting adjustment	0	0	0
Gasoline and heating oil contracts | Spire Missouri
ASSETS
Effects of Netting and Cash Margin Receivables /Payables		0	0
Derivative asset		0.1	0.2
Gasoline and heating oil contracts | Quoted Prices in Active Markets (Level 1) | Spire Missouri
ASSETS
Derivative asset before netting adjustment		0.1	0.2
Gasoline and heating oil contracts | Significant Observable Inputs (Level 2) | Spire Missouri
ASSETS
Derivative asset before netting adjustment		0	0
Gasoline and heating oil contracts | Significant Unobservable Inputs (Level 3) | Spire Missouri
ASSETS
Derivative asset before netting adjustment		0	0
Other
ASSETS
Effects of Netting and Cash Margin Receivables /Payables			0
Derivative asset			0.2
Other | Quoted Prices in Active Markets (Level 1)
ASSETS
Derivative asset before netting adjustment			0
Other | Significant Observable Inputs (Level 2)
ASSETS
Derivative asset before netting adjustment			0.2
Other | Significant Unobservable Inputs (Level 3)
ASSETS
Derivative asset before netting adjustment			0
Other | Interest rate swaps
ASSETS
Effects of Netting and Cash Margin Receivables /Payables	0
Derivative asset	1
LIABILITIES
Effects of Netting and Cash Margin Receivables /Payables		0
Derivative liability		0.9
Other | Interest rate swaps | Quoted Prices in Active Markets (Level 1)
ASSETS
Derivative asset before netting adjustment	0
LIABILITIES
Derivative liability before netting adjustment		0
Other | Interest rate swaps | Significant Observable Inputs (Level 2)
ASSETS
Derivative asset before netting adjustment	1
LIABILITIES
Derivative liability before netting adjustment		0.9
Other | Interest rate swaps | Significant Unobservable Inputs (Level 3)
ASSETS
Derivative asset before netting adjustment	0
LIABILITIES
Derivative liability before netting adjustment		0
Gas Utility | Operating Segments | US stock/bond mutual funds
ASSETS
Effects of Netting and Cash Margin Receivables /Payables	0	0	0
Derivative asset	23.2	22.4	21.8
Gas Utility | Operating Segments | US stock/bond mutual funds | Quoted Prices in Active Markets (Level 1)
ASSETS
Derivative asset before netting adjustment	19.1	18.3	17.7
Gas Utility | Operating Segments | US stock/bond mutual funds | Significant Observable Inputs (Level 2)
ASSETS
Derivative asset before netting adjustment	4.1	4.1	4.1
Gas Utility | Operating Segments | US stock/bond mutual funds | Significant Unobservable Inputs (Level 3)
ASSETS
Derivative asset before netting adjustment	0	0	0
Gas Utility | Operating Segments | NYMEX/ICE natural gas contracts
ASSETS
Effects of Netting and Cash Margin Receivables /Payables	(0.1)	(3.4)	(1.8)
Derivative asset	0	0	2.7
LIABILITIES
Effects of Netting and Cash Margin Receivables /Payables	(0.2)	(1.9)	(0.5)
Derivative liability	0	0	0
Gas Utility | Operating Segments | NYMEX/ICE natural gas contracts | Quoted Prices in Active Markets (Level 1)
ASSETS
Derivative asset before netting adjustment	0.1	3.4	4.5
LIABILITIES
Derivative liability before netting adjustment	0.2	1.9	0.5
Gas Utility | Operating Segments | NYMEX/ICE natural gas contracts | Significant Observable Inputs (Level 2)
ASSETS
Derivative asset before netting adjustment	0	0	0
LIABILITIES
Derivative liability before netting adjustment	0	0	0
Gas Utility | Operating Segments | NYMEX/ICE natural gas contracts | Significant Unobservable Inputs (Level 3)
ASSETS
Derivative asset before netting adjustment	0	0	0
LIABILITIES
Derivative liability before netting adjustment	0	0	0
Gas Utility | Operating Segments | Gasoline and heating oil contracts
ASSETS
Effects of Netting and Cash Margin Receivables /Payables		0	0
Derivative asset		0.1	0.2
Gas Utility | Operating Segments | Gasoline and heating oil contracts | Quoted Prices in Active Markets (Level 1)
ASSETS
Derivative asset before netting adjustment		0.1	0.2
Gas Utility | Operating Segments | Gasoline and heating oil contracts | Significant Observable Inputs (Level 2)
ASSETS
Derivative asset before netting adjustment		0	0
Gas Utility | Operating Segments | Gasoline and heating oil contracts | Significant Unobservable Inputs (Level 3)
ASSETS
Derivative asset before netting adjustment		0	0
Gas Marketing | Operating Segments
ASSETS
Effects of Netting and Cash Margin Receivables /Payables		(6.7)
Derivative asset		28.7
Gas Marketing | Operating Segments | Quoted Prices in Active Markets (Level 1)
ASSETS
Derivative asset before netting adjustment		23.1
Gas Marketing | Operating Segments | Significant Observable Inputs (Level 2)
ASSETS
Derivative asset before netting adjustment		12.2
Gas Marketing | Operating Segments | Significant Unobservable Inputs (Level 3)
ASSETS
Derivative asset before netting adjustment		0.1
Gas Marketing | Operating Segments | NYMEX/ICE natural gas contracts
ASSETS
Effects of Netting and Cash Margin Receivables /Payables	(3.5)	(2.1)	(4.4)
Derivative asset	0	0.5	0.2
LIABILITIES
Effects of Netting and Cash Margin Receivables /Payables	(10.4)	(2.1)	(6)
Derivative liability	0	0	0
Gas Marketing | Operating Segments | NYMEX/ICE natural gas contracts | Quoted Prices in Active Markets (Level 1)
ASSETS
Derivative asset before netting adjustment	0.2	1.3	1
LIABILITIES
Derivative liability before netting adjustment	0.6	1.8	2.1
Gas Marketing | Operating Segments | NYMEX/ICE natural gas contracts | Significant Observable Inputs (Level 2)
ASSETS
Derivative asset before netting adjustment	3.3	1.3	3.6
LIABILITIES
Derivative liability before netting adjustment	9.8	0.3	3.9
Gas Marketing | Operating Segments | NYMEX/ICE natural gas contracts | Significant Unobservable Inputs (Level 3)
ASSETS
Derivative asset before netting adjustment	0	0	0
LIABILITIES
Derivative liability before netting adjustment	0	0	0
Gas Marketing | Operating Segments | Natural gas commodity contracts
ASSETS
Effects of Netting and Cash Margin Receivables /Payables	(2.1)	(1.2)	(0.5)
Derivative asset	5.4	5.7	5.9
LIABILITIES
Effects of Netting and Cash Margin Receivables /Payables	(2.1)	(1.2)	(0.5)
Derivative liability	12.2	7.2	6
Gas Marketing | Operating Segments | Natural gas commodity contracts | Quoted Prices in Active Markets (Level 1)
ASSETS
Derivative asset before netting adjustment	0	0	0
LIABILITIES
Derivative liability before netting adjustment	0	0	0
Gas Marketing | Operating Segments | Natural gas commodity contracts | Significant Observable Inputs (Level 2)
ASSETS
Derivative asset before netting adjustment	7.4	6.8	6.2
LIABILITIES
Derivative liability before netting adjustment	14.3	8.4	6.5
Gas Marketing | Operating Segments | Natural gas commodity contracts | Significant Unobservable Inputs (Level 3)
ASSETS
Derivative asset before netting adjustment	0.1	0.1	0.2
LIABILITIES
Derivative liability before netting adjustment	$ 0	$ 0	$ 0

CONCENTRATIONS OF CREDIT RISK (

CONCENTRATIONS OF CREDIT RISK (Details) $ in Millions	6 Months Ended
	Mar. 31, 2018USD ($)subsegmentcounterparty
Concentration Risk [Line Items]
Number of groups with potential to affect overall exposure | subsegment	3
Number of large counterparties for which credit risk is disclosed | counterparty	5
Number of counterparties with investment-grade rating | counterparty	0
Number of counterparties with non-investment grade rating | counterparty	3
Energy Producers And Their Affiliates
Concentration Risk [Line Items]
Accounts receivable	$ 15.6
Net receivable amount	9.6
Utility Companies And Their Affiliates
Concentration Risk [Line Items]
Accounts receivable	30.7
Net receivable amount	29.4
Largest Counterparties
Concentration Risk [Line Items]
Accounts receivable	16.1
Net receivable amount	$ 14.9

PENSION PLANS AND OTHER POSTR40

PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS - Narrative (Details)	3 Months Ended		6 Months Ended
	Mar. 31, 2018USD ($)plan	Mar. 31, 2017USD ($)	Mar. 31, 2018USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2017
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
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Loss on lump-sum settlements	$ 9,400,000	$ 11,900,000	$ 9,400,000	$ 11,900,000
Regulatory adjustment	$ 24,000,000	(7,400,000)	28,300,000	(2,800,000)
Pension Plans | Spire Missouri
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of plans | plan	2
Lump-sum payments recognized as settlement	$ 39,500,000	36,300,000
Loss on lump-sum settlements	$ 9,400,000	11,500,000	$ 9,400,000	11,500,000
Discount rate on defined benefit plan	4.00%		4.00%		3.75%
Regulatory adjustment	$ 21,900,000	(8,600,000)	$ 24,300,000	(5,800,000)
Contributions made by employer			13,500,000
Anticipated contributions to pension plans for qualified trust	22,400,000		22,400,000
Pension Plans | Spire Alabama
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Lump-sum payments recognized as settlement		1,900,000
Loss on lump-sum settlements	0	400,000	0	400,000
Regulatory adjustment	$ 1,900,000	1,100,000	3,600,000	2,700,000
Contributions made by employer			$ 0
Other Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate on defined benefit plan	4.00%		4.00%		3.70%
Other Pension Plans | Spire Missouri
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions made by employer			$ 0
Anticipated contributions to pension plans for qualified trust	$ 500,000		500,000
Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Regulatory adjustment	0	(800,000)	100,000	(1,600,000)
Contributions made by employer			1,700,000
Postretirement Plans | Spire Missouri
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Regulatory adjustment	500,000	(300,000)	1,000,000	(700,000)
Anticipated contributions to pension plans for qualified trust	5,200,000		5,200,000
Anticipated payment directly to participants in postretirement plan			800,000
Postretirement Plans | Spire Alabama
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Regulatory adjustment	(500,000)	$ (500,000)	(900,000)	$ (900,000)
Contributions made by employer			0
Anticipated contributions to pension plans for qualified trust	0		$ 0
MoPSC | ISRS surcharge | Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Regulatory adjustment	$ 28,800,000

PENSION PLANS AND OTHER POSTR41

PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS - Net Periodic Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost – benefits earned during the period	$ 5.2	$ 5.2	$ 10.4	$ 10.5
Interest cost on projected benefit obligation	6.9	6.9	13.8	13.8
Expected return on plan assets	(9.5)	(9.7)	(19.2)	(19.6)
Amortization of prior service credit	(0.2)	0.3	(0.5)	0.5
Amortization of actuarial gain (loss)	2.9	3.2	6	6.6
Loss on lump-sum settlements	9.4	11.9	9.4	11.9
Subtotal	14.7	17.8	19.9	23.7
Regulatory adjustment	24	(7.4)	28.3	(2.8)
Net pension cost (income)	38.7	10.4	48.2	20.9
Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost – benefits earned during the period	2.4	2.7	4.7	5.5
Interest cost on projected benefit obligation	2.2	2.2	4.4	4.3
Expected return on plan assets	(3.5)	(3.4)	(7)	(6.8)
Amortization of prior service credit	(0.1)	0	(0.1)	0
Amortization of actuarial gain (loss)	0.2	0.6	0.4	1.2
Subtotal	1.2	2.1	2.4	4.2
Regulatory adjustment	0	(0.8)	0.1	(1.6)
Net pension cost (income)	1.2	1.3	2.5	2.6
Spire Missouri | Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost – benefits earned during the period	3.2	3.3	6.5	6.6
Interest cost on projected benefit obligation	4.9	4.9	9.8	9.7
Expected return on plan assets	(7)	(7.1)	(14.2)	(14.4)
Amortization of prior service credit	0.2	0.3	0.4	0.5
Amortization of actuarial gain (loss)	2.5	2.8	5.1	5.7
Loss on lump-sum settlements	9.4	11.5	9.4	11.5
Subtotal	13.2	15.7	17	19.6
Regulatory adjustment	21.9	(8.6)	24.3	(5.8)
Net pension cost (income)	35.1	7.1	41.3	13.8
Spire Missouri | Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost – benefits earned during the period	2.3	2.6	4.5	5.2
Interest cost on projected benefit obligation	1.8	1.7	3.6	3.4
Expected return on plan assets	(2.5)	(2.2)	(4.9)	(4.5)
Amortization of prior service credit	0	0	0.1	0.1
Amortization of actuarial gain (loss)	0.2	0.7	0.4	1.3
Subtotal	1.8	2.8	3.7	5.5
Regulatory adjustment	0.5	(0.3)	1	(0.7)
Net pension cost (income)	2.3	2.5	4.7	4.8
Spire Alabama | Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost – benefits earned during the period	1.7	1.5	3.3	3.1
Interest cost on projected benefit obligation	1.4	1.5	2.8	3
Expected return on plan assets	(1.7)	(1.8)	(3.4)	(3.6)
Amortization of prior service credit	(0.4)	0	(0.9)	0
Amortization of actuarial gain (loss)	0.4	0.4	0.9	0.9
Loss on lump-sum settlements	0	0.4	0	0.4
Subtotal	1.4	2	2.7	3.8
Regulatory adjustment	1.9	1.1	3.6	2.7
Net pension cost (income)	3.3	3.1	6.3	6.5
Spire Alabama | Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost – benefits earned during the period	0.1	0.1	0.1	0.2
Interest cost on projected benefit obligation	0.3	0.4	0.7	0.8
Expected return on plan assets	(1)	(1.1)	(2)	(2.2)
Amortization of prior service credit	(0.1)	0	(0.2)	(0.1)
Amortization of actuarial gain (loss)	0	(0.1)	0	(0.1)
Subtotal	(0.7)	(0.7)	(1.4)	(1.4)
Regulatory adjustment	(0.5)	(0.5)	(0.9)	(0.9)
Net pension cost (income)	$ (1.2)	$ (1.2)	$ (2.3)	$ (2.3)

INFORMATION BY OPERATING SEGM42

INFORMATION BY OPERATING SEGMENT - Narrative (Details) - reporting_unit	6 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Number of reportable segments	2
Ryckman Creek Resources, LLC
Segment Reporting Information [Line Items]
Voting interest acquired		80.00%

INFORMATION BY OPERATING SEGM43

INFORMATION BY OPERATING SEGMENT - Schedule of Operating Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Sep. 30, 2017
Operating Segment Information [Abstract]
Total revenues including intersegment revenues	$ 813.4	$ 663.4	$ 1,375.2	$ 1,158.5
Total Operating Revenues	813.4	663.4	1,375.2	1,158.5
Gas Utility
Natural and propane gas	383.7	254.3	624.5	448.1
Operation and maintenance	143.6	98.4	241.5	197.8
Depreciation and amortization	41.1	37.9	81.4	75.6
Taxes, other than income taxes	58	48.3	94.7	81.7
Total Gas Utility Operating Expenses	626.4	438.9	1,042.1	803.2
Gas Marketing and other	45.2	44.1	86.2	85.8
Total Operating Expenses	671.6	483	1,128.3	889
Operating Income	141.8	180.4	246.9	269.5
Net Economic Earnings (Loss)	137.2	109	195.1	156.5
Total Assets	6,586.8	6,256.7	6,586.8	6,256.7	$ 6,546.7
Intersegment revenues
Operating Segment Information [Abstract]
Total revenues including intersegment revenues	0	0	0	0
Other
Operating Segment Information [Abstract]
Total revenues including intersegment revenues	1.5	0.1	1.8	1.2
Total Operating Revenues	4.4	1.8	7.2	3.6
Gas Utility
Natural and propane gas	0	0	0	0
Operation and maintenance	0	0	0	0
Depreciation and amortization	0	0	0	0
Taxes, other than income taxes	0	0	0	0
Total Gas Utility Operating Expenses	0	0	0	0
Gas Marketing and other	6.4	2.3	10.9	4.3
Total Operating Expenses	6.4	2.3	10.9	4.3
Operating Income	(2)	(0.5)	(3.7)	(0.7)
Net Economic Earnings (Loss)	(4.7)	(3.2)	(9.9)	(8.9)
Total Assets	2,211.9	2,199.1	2,211.9	2,199.1	2,239.5
Other | Intersegment revenues
Operating Segment Information [Abstract]
Total revenues including intersegment revenues	2.9	1.7	5.4	2.4
Eliminations
Operating Segment Information [Abstract]
Total revenues including intersegment revenues	0	0	0	0
Total Operating Revenues	(3.1)	(4.3)	(5.7)	(9.4)
Gas Utility
Natural and propane gas	(19.5)	(21.3)	(42.1)	(42)
Operation and maintenance	(2.2)	(0.9)	(4.1)	(2)
Depreciation and amortization	0	0	0	0
Taxes, other than income taxes	0	0	0	0
Total Gas Utility Operating Expenses	(21.7)	(22.2)	(46.2)	(44)
Gas Marketing and other	18.6	17.9	40.5	34.6
Total Operating Expenses	(3.1)	(4.3)	(5.7)	(9.4)
Operating Income	0	0	0	0
Net Economic Earnings (Loss)	0	0	0	0
Total Assets	(1,318)	(1,451.4)	(1,318)	(1,451.4)	(1,490.2)
Eliminations | Intersegment revenues
Operating Segment Information [Abstract]
Total revenues including intersegment revenues	(3.1)	(4.3)	(5.7)	(9.4)
Gas Utility | Operating Segments
Operating Segment Information [Abstract]
Total revenues including intersegment revenues	790.6	641.1	1,332.5	1,113.4
Total Operating Revenues	790.8	643.7	1,332.8	1,120.4
Gas Utility
Natural and propane gas	403.2	275.6	666.6	490.1
Operation and maintenance	145.8	99.3	245.6	199.8
Depreciation and amortization	41.1	37.9	81.4	75.6
Taxes, other than income taxes	58	48.3	94.7	81.7
Total Gas Utility Operating Expenses	648.1	461.1	1,088.3	847.2
Gas Marketing and other	0	0	0	0
Total Operating Expenses	648.1	461.1	1,088.3	847.2
Operating Income	142.7	182.6	244.5	273.2
Net Economic Earnings (Loss)	131.7	112.2	191.2	164
Total Assets	5,484.3	5,290.8	5,484.3	5,290.8	5,551.2
Gas Utility | Operating Segments | Intersegment revenues
Operating Segment Information [Abstract]
Total revenues including intersegment revenues	0.2	2.6	0.3	7
Gas Marketing | Operating Segments
Operating Segment Information [Abstract]
Total revenues including intersegment revenues	21.3	22.2	40.9	43.9
Total Operating Revenues	21.3	22.2	40.9	43.9
Gas Utility
Natural and propane gas	0	0	0	0
Operation and maintenance	0	0	0	0
Depreciation and amortization	0	0	0	0
Taxes, other than income taxes	0	0	0	0
Total Gas Utility Operating Expenses	0	0	0	0
Gas Marketing and other	20.2	23.9	34.8	46.9
Total Operating Expenses	20.2	23.9	34.8	46.9
Operating Income	1.1	(1.7)	6.1	(3)
Net Economic Earnings (Loss)	10.2	0	13.8	1.4
Total Assets	208.6	218.2	208.6	218.2	$ 246.2
Gas Marketing | Operating Segments | Intersegment revenues
Operating Segment Information [Abstract]
Total revenues including intersegment revenues	$ 0	$ 0	$ 0	$ 0

INFORMATION BY OPERATING SEGM44

INFORMATION BY OPERATING SEGMENT - Reconciliation of Consolidated Net Economic Earnings to Consolidated Net Income (Details) - USD ($) $ in Millions	Mar. 07, 2018	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting [Abstract]
Net Income		$ 98.2	$ 108	$ 214.2	$ 153.2
Missouri regulatory adjustments		30.6	0	30.6	0
Unrealized loss on energy-related derivative contracts		11.8	1.6	12.6	5.4
Lower of cost or market inventory adjustments		0	0.1	0	0
Realized gain on economic hedges prior to sale of the physical commodity		(0.2)	(0.1)	(0.3)	(0.2)
Acquisition, divestiture and restructuring activities		2	0.1	3.7	0.2
Income tax effect of adjustments		(11.1)	(0.7)	(11.7)	(2.1)
Effects of the Tax Cuts and Jobs Act	$ 33	5.9	0	(54)	0
Net Economic Earnings		$ 137.2	$ 109	$ 195.1	$ 156.5

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Commitments (Details) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2018	Apr. 27, 2018
Long-term Purchase Commitment [Line Items]
Minimum total payments required for natural gas contracts	$ 1,117.9
Spire Missouri
Long-term Purchase Commitment [Line Items]
Minimum total payments required for natural gas contracts	465.1
Spire Alabama
Long-term Purchase Commitment [Line Items]
Minimum total payments required for natural gas contracts	$ 288.5
Spire STL Pipeline LLC | Subsequent Event
Long-term Purchase Commitment [Line Items]
Contractual commitment		$ 95

COMMITMENTS AND CONTINGENCIES46

COMMITMENTS AND CONTINGENCIES - Contingencies (Details)	Dec. 17, 2013fatality	Mar. 31, 2018lawsuitsiteplaintiff	Sep. 30, 2013site
Spire Gulf
Loss Contingencies [Line Items]
Number of lawsuits filed | lawsuit		14
Number of plaintiffs | plaintiff		1,600
Spire Missouri
Loss Contingencies [Line Items]
Number of former manufactured gas plant (MGP) sites in Missouri		3
Number of former manufactured gas plant (MGP) sites enrolled in BVCP		2
Spire Alabama
Loss Contingencies [Line Items]
Number of former manufactured gas plant (MGP)		9
Number of incident fatalities | fatality	1
Number of former manufactured gas distribution		5
Previous Ownership | Spire Missouri
Loss Contingencies [Line Items]
Number of former manufactured gas plant (MGP)			19
Previous Ownership | Missouri Gas Energy (MGE)
Loss Contingencies [Line Items]
Number of former manufactured gas plant (MGP)		7
Current Ownership | Spire Alabama
Loss Contingencies [Line Items]
Number of former manufactured gas plant (MGP)		4
Number of former manufactured gas distribution		1
Pending Litigation | Spire Gulf
Loss Contingencies [Line Items]
Number of plaintiffs | plaintiff		31

INCOME TAXES - Impact of Tax Cu

INCOME TAXES - Impact of Tax Cuts and Jobs Act (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)
Deferred Income Tax Assets And Liabilities [Line Items]
Adjustment to deferred tax assets	$ 0
Adjustment to deferred tax liabilities	(299.5)
Adjustment to deferred income tax expense	(69.4)
Adjustment to regulatory assets	(59.4)
Adjustment to regulatory liabilities	170.7
Spire Missouri
Deferred Income Tax Assets And Liabilities [Line Items]
Adjustment to deferred tax assets	0
Adjustment to deferred tax liabilities	(268.2)
Adjustment to deferred income tax expense	(54.6)
Adjustment to regulatory assets	(61)
Adjustment to regulatory liabilities	152.6
Spire Alabama
Deferred Income Tax Assets And Liabilities [Line Items]
Adjustment to deferred tax assets	(60.8)
Adjustment to deferred tax liabilities	0
Adjustment to deferred income tax expense	59.2
Adjustment to regulatory assets	1.6
Adjustment to regulatory liabilities	$ 0