Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Net Income (Loss)	$ 81.3	$ 85.1
Other Comprehensive Income (Loss), Before Tax:
Net hedging gain (loss) arising during the period	17.6	(15.4)
Amounts reclassified into net income	(1.7)	(9.0)
Net gain (loss) on cash flow hedging derivative instruments	15.9	(24.4)
Net gain on defined benefit pension and other postretirement plans	0.1	0.1
Net unrealized gain on available for sale securities	0.0	0.1
Other Comprehensive Income (Loss), Before Tax	16.0	(24.2)
Income Tax Expense (Benefit) Related to Items of Other Comprehensive Income (Loss)	3.7	(5.7)
Other Comprehensive Income (Loss), Net of Tax	12.3	(18.5)
Comprehensive Income	93.6	66.6
Operating Revenues	669.1	756.6
Operating Expenses:
Natural gas	270.0	367.0
Operation and maintenance	129.3	130.7
Depreciation and amortization	72.3	67.0
Taxes, other than income taxes	48.7	52.7
Total Operating Expenses	520.3	617.4
Operating Income	148.8	139.2
Interest Expense, Net	48.0	50.6
Other Income, Net	0.6	17.5
Income Before Income Taxes	101.4	106.1
Income Tax expense	20.1	21.0
Net Income (Loss)	81.3	85.1
Other Comprehensive Income, Net of Tax	12.3	(18.5)
Comprehensive Income	93.6	66.6
Spire Missouri [Member]
Net Income (Loss)	53.4	57.0
Other Comprehensive Income (Loss), Before Tax:
Other Comprehensive Income (Loss), Net of Tax	0.1	0.1
Comprehensive Income	53.5	57.1
Operating Revenues	457.5	535.4
Operating Expenses:
Natural gas	213.6	292.6
Operation and maintenance	76.2	74.9
Depreciation and amortization	45.7	42.1
Taxes, other than income taxes	36.6	38.5
Total Operating Expenses	372.1	448.1
Operating Income	85.4	87.3
Interest Expense, Net	25.3	27.9
Other Income, Net	1.5	7.2
Income Before Income Taxes	61.6	66.6
Income Tax expense	8.2	9.6
Net Income (Loss)	53.4	57.0
Other Comprehensive Income, Net of Tax	0.1	0.1
Comprehensive Income	$ 53.5	$ 57.1