Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2023		Mar. 31, 2022
Operating Activities:
Net Income	$ 270.2		$ 229.3
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	124.7		115.8
Deferred income taxes and investment tax credits	62.5		59.1
Changes in assets and liabilities:
Accounts receivable	43.7		(3.4)
Inventories	218.2		136.9
Regulatory assets and liabilities	(35.5)		(230.5)
Accounts payable	(372.9)		(21.1)
Delayed/advance customer billings, net	(76.3)		(71.4)
Taxes accrued	(10.8)		(11.2)
Other assets and liabilities	(50.6)		(51.4)
Other	6.7		3.0
Net cash provided by operating activities	179.9		155.1
Delayed/advance customer billings, net	(76.3)		(71.4)
Investing Activities:
Capital expenditures	(307.8)		(275.9)
Advance payment for business acquisition	(37.1)		0.0
Other	4.2		2.7
Net cash used in investing activities	(340.7)		(273.2)
Financing Activities:
Issuance of long-term debt	755.0		300.0
Repayment of long-term debt	(31.2)		(55.8)
Repayment of short-term debt, net	(476.5)		(64.9)
Issuance of common stock	3.6		24.0
Dividends paid on common stock	(74.5)		(70.1)
Dividends paid on preferred stock	(7.4)		(7.4)
Other financing activities	(7.5)		(3.8)
Net cash provided by financing activities	161.5		122.0
Net Increase in Cash, Cash Equivalents, and Restricted Cash	0.7		3.9
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	20.5		11.3
Cash, Cash Equivalents, and Restricted Cash at End of Period	21.2		15.2
Supplemental disclosure of cash paid for:
Interest, net of amounts capitalized	(80.5)		(56.5)
Income taxes	(1.4)		(0.2)
Spire Missouri [Member]
Operating Activities:
Net Income	159.4	[1]	143.5
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	77.8		70.1
Deferred income taxes and investment tax credits	24.8		26.9
Changes in assets and liabilities:
Accounts receivable	(208.9)		18.2
Inventories	126.2		92.4
Regulatory assets and liabilities	0.6		(181.3)
Accounts payable	(31.5)		12.9
Delayed/advance customer billings, net	(75.4)		(70.8)
Taxes accrued	(3.2)		(3.8)
Other assets and liabilities	(47.4)		(41.7)
Other	0.8		0.7
Net cash provided by operating activities	23.2		67.1
Delayed/advance customer billings, net	(75.4)		(70.8)
Investing Activities:
Capital expenditures	(206.6)		(176.0)
Other	1.8		1.4
Net cash used in investing activities	(204.8)		(174.6)
Financing Activities:
Issuance of long-term debt	400.0		300.0
Issuance of common stock	0.0		23.3
Dividends paid on common stock	(30.0)		0.0
Other financing activities	(3.9)		(2.0)
Net cash provided by financing activities	181.6		107.5
Net Increase in Cash, Cash Equivalents, and Restricted Cash	0.0		0.0
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		0.0
Issuance (repayment) of short-term debt, net	200.0		(250.0)
Borrowings from (repayments to) Spire, net	(384.5)		36.2
Supplemental disclosure of cash paid for:
Interest, net of amounts capitalized	(44.1)		(28.3)
Income taxes	0.0		0.0
Spire Alabama Inc [Member]
Operating Activities:
Net Income	69.2		74.6
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	34.0		33.2
Deferred income taxes and investment tax credits	23.4		25.1
Changes in assets and liabilities:
Accounts receivable	(4.8)		(34.9)
Inventories	26.9		1.3
Regulatory assets and liabilities	(32.3)		(50.7)
Accounts payable	(39.2)		7.4
Delayed/advance customer billings, net	(0.7)		(0.6)
Taxes accrued	(4.9)		(6.1)
Other assets and liabilities	12.6		(14.2)
Other	0.2		(0.1)
Net cash provided by operating activities	84.4		35.0
Delayed/advance customer billings, net	(0.7)		(0.6)
Investing Activities:
Capital expenditures	(72.9)		(71.0)
Other	0.7		0.6
Net cash used in investing activities	(72.2)		(70.4)
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	(13.6)		35.6
Net Increase in Cash, Cash Equivalents, and Restricted Cash	(1.4)		0.2
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	2.4		0.0
Cash, Cash Equivalents, and Restricted Cash at End of Period	1.0		0.2
Borrowings from (repayments to) Spire, net	(139.6)		107.6
Return of capital to Spire	(27.0)		(6.0)
Supplemental disclosure of cash paid for:
Interest, net of amounts capitalized	(12.6)		(10.1)
Income taxes	$ 0.0		$ 0.0

[1] Accumulated other comprehensive income (loss)