Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Jun. 30, 2023		Jun. 30, 2022
Operating Activities:
Net Income	$ 248.6		$ 227.9
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	189.0		176.2
Deferred income taxes and investment tax credits	55.7		57.0
Changes in assets and liabilities:
Accounts receivable	284.1		9.1
Inventories	179.3		4.9
Regulatory assets and liabilities	(18.0)		(323.8)
Accounts payable	(405.6)		180.3
Delayed/advance customer billings, net	(48.5)		(60.8)
Taxes accrued	(2.3)		(2.2)
Other assets and liabilities	(88.4)		(70.1)
Other	10.2		6.1
Net cash provided by operating activities	404.1		204.6
Investing Activities:
Capital expenditures	(483.3)		(402.5)
Business acquisition	(37.0)		0.0
Other	3.9		4.2
Net cash used in investing activities	(516.4)		(398.3)
Financing Activities:
Issuance of long-term debt	755.0		300.0
Repayment of long-term debt	(31.2)		(55.8)
(Repayment) issuance of short-term debt, net	(479.9)		37.2
Issuance of common stock	4.0		51.9
Dividends paid on common stock	(112.5)		(105.9)
Dividends paid on preferred stock	(11.1)		(11.1)
Other financing activities	(7.5)		(3.8)
Net cash provided by financing activities	116.8		212.5
Net Increase in Cash, Cash Equivalents, and Restricted Cash	4.5		18.8
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	20.5		11.3
Cash, Cash Equivalents, and Restricted Cash at End of Period	25.0		30.1
Supplemental disclosure of cash paid for:
Interest, net of amounts capitalized	(118.2)		(80.2)
Income taxes	(1.8)		(0.7)
Spire Missouri [Member]
Operating Activities:
Net Income	145.6	[1]	135.1
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	117.8		107.4
Deferred income taxes and investment tax credits	21.2		23.8
Changes in assets and liabilities:
Accounts receivable	(33.3)		167.6
Inventories	113.7		29.4
Regulatory assets and liabilities	1.2		(260.8)
Accounts payable	(43.6)		25.8
Delayed/advance customer billings, net	(47.9)		(61.0)
Taxes accrued	(1.1)		(0.2)
Other assets and liabilities	(88.4)		(48.5)
Other	1.3		1.0
Net cash provided by operating activities	186.5		119.6
Investing Activities:
Capital expenditures	(324.8)		(258.7)
Other	2.9		2.6
Net cash used in investing activities	(321.9)		(256.1)
Financing Activities:
Issuance of long-term debt	400.0		300.0
Issuance of common stock	0.0		51.1
Dividends paid on common stock	(43.5)		0.0
Other financing activities	(3.9)		(2.1)
Net cash provided by financing activities	135.4		143.5
Net Increase in Cash, Cash Equivalents, and Restricted Cash	0.0		7.0
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	0.0		0.0
Cash, Cash Equivalents, and Restricted Cash at End of Period	0.0		7.0
Repayment of short-term debt, net	0.0		(250.0)
(Repayments to) Borrowings from Spire, net	(217.2)		44.5
Supplemental disclosure of cash paid for:
Interest, net of amounts capitalized	(64.7)		(43.9)
Income taxes	0.0		0.0
Spire Alabama Inc [Member]
Operating Activities:
Net Income	70.5		85.1
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	51.5		50.1
Deferred income taxes and investment tax credits	24.0		28.7
Changes in assets and liabilities:
Accounts receivable	16.6		(42.7)
Inventories	16.4		(38.1)
Regulatory assets and liabilities	(16.8)		(67.4)
Accounts payable	(39.9)		41.6
Delayed/advance customer billings, net	(0.6)		(0.1)
Taxes accrued	0.3		(1.2)
Other assets and liabilities	3.3		(17.4)
Other	0.3		0.0
Net cash provided by operating activities	125.6		38.6
Investing Activities:
Capital expenditures	(98.4)		(105.0)
Other	0.7		0.7
Net cash used in investing activities	(97.7)		(104.3)
Financing Activities:
Issuance of long-term debt	175.0		0.0
Repayment of long-term debt	0.0		(50.0)
Dividends paid on common stock	(21.0)		(16.0)
Other financing activities	(1.0)		0.0
Net cash provided by financing activities	(29.8)		69.4
Net Increase in Cash, Cash Equivalents, and Restricted Cash	(1.9)		3.7
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	2.4		0.0
Cash, Cash Equivalents, and Restricted Cash at End of Period	0.5		3.7
(Repayments to) Borrowings from Spire, net	(152.8)		147.4
Return of capital to Spire	(30.0)		(12.0)
Supplemental disclosure of cash paid for:
Interest, net of amounts capitalized	(23.3)		(14.7)
Income taxes	$ 0.0		$ 0.0

[1] Accumulated other comprehensive income (loss)