CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Net Income	$ 187.4	$ 133.6	$ 276.3	$ 200.6
Cash flow hedging derivative instruments:
Net hedging gain (loss) arising during the period	43.5	(41.1)	60.7	(22.2)
Amounts reclassified into net income	(0.4)	(2.2)	(0.7)	(2.5)
Net gain (loss) on cash flow hedging derivative instruments	43.1	(43.3)	60.0	(24.7)
Net gain (loss) on defined benefit pension and other postretirement plans	0.2	(0.1)	0.2	(0.1)
Net unrealized loss on available for sale securities	(0.1)		(0.1)
Other Comprehensive Income (Loss), Before Tax	43.2	(43.4)	60.1	(24.8)
Income Tax Expense (Benefit) Related to Items of Other Comprehensive Income	9.8	(9.7)	13.6	(5.5)
Other Comprehensive Income (Loss), Net of Tax	33.4	(33.7)	46.5	(19.3)
Comprehensive Income	220.8	99.9	322.8	181.3
Operating Revenues	1,104.9	715.5	1,617.5	1,282.4
Operating Expenses:
Natural gas	619.1	297.1	800.3	559.0
Operation and maintenance	119.0	105.7	230.6	222.3
Depreciation and amortization	51.5	49.2	102.3	96.7
Taxes, other than income taxes	57.9	53.0	94.0	91.6
Total Operating Expenses	847.5	505.0	1,227.2	969.6
Operating Income	257.4	210.5	390.3	312.8
Interest Expense, Net	25.8	27.2	51.5	53.9
Other Income (Expense), Net	1.8	(19.5)	6.1	(13.8)
Income Before Income Taxes	233.4	163.8	344.9	245.1
Income Tax Expense	46.0	30.2	68.6	44.5
Spire Missouri
Net Income	93.1	74.5	149.7	122.5
Cash flow hedging derivative instruments:
Other Comprehensive Income (Loss), Net of Tax	0.1	(0.2)	0.2	(0.1)
Comprehensive Income	93.2	74.3	149.9	122.4
Operating Revenues	790.9	457.5	1,146.4	831.5
Operating Expenses:
Natural gas	537.4	223.6	699.0	409.4
Operation and maintenance	62.8	50.8	125.7	116.3
Depreciation and amortization	31.0	29.3	61.4	58.3
Taxes, other than income taxes	38.9	36.1	64.0	62.8
Total Operating Expenses	670.1	339.8	950.1	646.8
Operating Income	120.8	117.7	196.3	184.7
Interest Expense, Net	11.7	12.7	23.4	25.9
Other Income (Expense), Net	0.8	(20.9)	3.5	(19.9)
Income Before Income Taxes	109.9	84.1	176.4	138.9
Income Tax Expense	$ 16.8	$ 9.6	$ 26.7	$ 16.4