Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Mar. 31, 2023		Mar. 31, 2022	Mar. 31, 2023		Mar. 31, 2022
Net Income	$ 179.2		$ 173.6	$ 270.2		$ 229.3
Other Comprehensive (Loss) Income, Before Tax:
Net hedging (loss) gain arising during the period	(6.8)		18.7	(9.8)		13.9
Amounts reclassified into regulatory liabilities	(17.5)		0.0	(17.5)		0.0
Amounts reclassified into net income	(0.5)		(0.4)	(0.8)		(0.7)
Net (loss) gain on cash flow hedging derivative instruments	(24.8)		18.3	(28.1)		13.2
Net gain on defined benefit pension and other postretirement plans	0.1		0.1	0.2		0.2
Net unrealized loss on available for sale securities	0.0		(0.1)	0.0		(0.2)
Other Comprehensive (Loss) Income, Before Tax	(24.7)		18.3	(27.9)		13.2
Income Tax (Benefit) Expense Related to Items of Other Comprehensive Income or Loss	(5.8)		4.3	(6.6)		3.1
Other Comprehensive (Loss) Income, Net of Tax	(18.9)		14.0	(21.3)		10.1
Comprehensive Income	160.3		187.6	248.9		239.4
Operating Revenues	1,123.4		880.9	1,937.4		1,436.3
Operating Expenses:
Natural gas	586.5		392.0	1,005.7		641.2
Operation and maintenance	132.1		113.2	264.2		229.6
Depreciation and amortization	62.6		58.9	124.7		115.8
Taxes, other than income taxes	81.9		71.6	132.3		109.2
Total Operating Expenses	863.1		635.7	1,526.9		1,095.8
Operating Income	260.3		245.2	410.5		340.5
Interest Expense, Net	47.2		27.5	90.8		56.1
Other Income (Expense), Net	7.0		(3.4)	13.0		4.0
Income Before Income Taxes	220.1		214.3	332.7		288.4
Income Tax Expense	40.9		40.7	62.5		59.1
Net Income	179.2		173.6	270.2		229.3
Other Comprehensive Income, Net of Tax	(18.9)		14.0	(21.3)		10.1
Comprehensive Income	160.3		187.6	248.9		239.4
Spire Missouri [Member]
Net Income	112.1	[1]	98.2	159.4	[1]	143.5
Other Comprehensive (Loss) Income, Before Tax:
Other Comprehensive (Loss) Income, Net of Tax	0.1	[1]	0.1	0.2	[1]	0.2
Comprehensive Income	112.2		98.3	159.6		143.7
Operating Revenues	791.0		571.2	1,332.2		919.1
Operating Expenses:
Natural gas	465.7		287.8	782.4		444.1
Operation and maintenance	77.4		64.3	154.5		130.6
Depreciation and amortization	39.2		35.9	77.8		70.1
Taxes, other than income taxes	61.2		53.0	97.6		78.7
Total Operating Expenses	643.5		441.0	1,112.3		723.5
Operating Income	147.5		130.2	219.9		195.6
Interest Expense, Net	24.6		14.2	46.6		28.7
Other Income (Expense), Net	5.9		(2.4)	10.9		3.5
Income Before Income Taxes	128.8		113.6	184.2		170.4
Income Tax Expense	16.7		15.4	24.8		26.9
Net Income	112.1	[1]	98.2	159.4	[1]	143.5
Other Comprehensive Income, Net of Tax	0.1	[1]	0.1	0.2	[1]	0.2
Comprehensive Income	$ 112.2		$ 98.3	$ 159.6		$ 143.7

[1] Accumulated other comprehensive income (loss)