CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating Activities:
Net Income	$ 55.7	$ 88.9
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Depreciation and amortization	56.9	50.8
Deferred income taxes and investment tax credits	18.4	21.8
Changes in assets and liabilities:
Accounts receivable	(152.8)	(169.6)
Inventories	(20.5)	9.5
Regulatory assets and liabilities	(187.3)	11.2
Accounts payable	42.9	43.9
Delayed/advance customer billings, net	(2.9)	(5.8)
Taxes accrued	(31.4)	(30.2)
Other assets and liabilities	(9.6)	(15.4)
Other	0.7	2.5
Net cash (used in) provided by operating activities	(229.9)	7.6
Investing Activities:
Capital expenditures	(145.7)	(163.6)
Other	2.6	0.0
Net cash used in investing activities	(143.1)	(163.6)
Financing Activities:
Issuance of long-term debt	300.0	150.0
Repayment of long-term debt	(55.8)	(5.4)
Issuance of short-term debt, net	174.0	48.1
Issuance of common stock	0.4	0.4
Dividends paid on common stock	(34.6)	(32.2)
Dividends paid on preferred stock	(3.7)	(3.7)
Other	(3.4)	(1.8)
Net cash provided by financing activities	376.9	155.4
Net Increase (Decrease) in Cash, Cash Equivalents, and Restricted Cash	3.9	(0.6)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	11.3	4.1
Cash, Cash Equivalents, and Restricted Cash at End of Period	15.2	3.5
Supplemental disclosure of cash (paid) received for:
Interest, net of amounts capitalized	(23.3)	(15.5)
Income taxes	(0.2)	0.1
Spire Missouri
Operating Activities:
Net Income	45.3	56.6
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Depreciation and amortization	34.2	30.4
Deferred income taxes and investment tax credits	11.5	9.9
Changes in assets and liabilities:
Accounts receivable	(74.9)	(88.7)
Inventories	(11.1)	6.3
Regulatory assets and liabilities	(161.3)	7.2
Accounts payable	38.3	24.3
Delayed/advance customer billings, net	(2.0)	(5.6)
Taxes accrued	(25.8)	(25.7)
Other assets and liabilities	3.8	(8.6)
Other	0.2	0.2
Net cash (used in) provided by operating activities	(141.8)	6.3
Investing Activities:
Capital expenditures	(96.3)	(99.1)
Other	0.4	0.3
Net cash used in investing activities	(95.9)	(98.8)
Financing Activities:
Issuance of long-term debt	300.0	0.0
Repayments to Spire, net	(60.6)	92.5
Other	(1.7)	0.0
Net cash provided by financing activities	237.7	92.5
Net Increase (Decrease) 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
Supplemental disclosure of cash (paid) received for:
Interest, net of amounts capitalized	(15.3)	(9.6)
Income taxes	0.0	0.0
Spire Alabama
Operating Activities:
Net Income	12.2	13.7
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Depreciation and amortization	16.5	15.0
Deferred income taxes and investment tax credits	4.2	4.8
Changes in assets and liabilities:
Accounts receivable	(36.5)	(37.8)
Inventories	(11.1)	(2.1)
Regulatory assets and liabilities	(21.4)	2.9
Accounts payable	15.8	10.4
Delayed/advance customer billings, net	(0.9)	(0.1)
Taxes accrued	(3.2)	(3.3)
Other assets and liabilities	(2.0)	(0.9)
Other	(0.2)	0.1
Net cash (used in) provided by operating activities	(26.6)	2.7
Investing Activities:
Capital expenditures	(34.7)	(40.9)
Other	0.6	0.0
Net cash used in investing activities	(34.1)	(40.9)
Financing Activities:
Issuance of long-term debt	0.0	150.0
Repayment of long-term debt	(50.0)	0.0
Return of capital to Spire	(6.0)	(11.0)
Repayments to Spire, net	124.7	(94.4)
Dividends paid on common stock	(8.0)	(5.5)
Other	0.0	(0.9)
Net cash provided by financing activities	60.7	38.2
Net Increase (Decrease) 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
Supplemental disclosure of cash (paid) received for:
Interest, net of amounts capitalized	(5.2)	(3.6)
Income taxes	$ 0.0	$ 0.0