CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Net Income	$ 88.6	$ 184.6	$ 214.2
Cash flow hedging derivative instruments:
Net hedging (loss) gain arising during the period	(8.9)	(46.4)	3.9
Amounts reclassified into net income	(3.2)	(1.3)	(1.5)
Net (loss) gain on cash flow hedging derivative instruments	(12.1)	(47.7)	2.4
Defined benefit pension and other postretirement benefit plans:
Amortization of actuarial (gain) loss included in net periodic pension and postretirement benefit cost	(0.5)	(0.9)	0.4
Net defined benefit pension and other postretirement benefit plans	(0.5)	(0.9)	0.4
Net unrealized gain on available-for-sale debt securities		0.1	0.3
Other Comprehensive (Loss) Income, Before Tax	(12.6)	(48.5)	3.1
Income Tax (Benefit) Expense Related to Items of Other Comprehensive (Loss) Income	(2.7)	(10.8)	0.6
Other Comprehensive (Loss) Income, Net of Tax	(9.9)	(37.7)	2.5
Comprehensive Income	78.7	146.9	216.7
Operating Revenues	1,855.4	1,952.4	1,965.0
Operating Expenses:
Natural gas	696.1	840.3	871.7
Operation and maintenance	458.6	474.1	477.3
Depreciation and amortization	197.3	181.7	168.4
Taxes, other than income taxes	148.4	154.0	153.5
Total Operating Expenses	1,649.0	1,650.1	1,670.9
Operating Income	206.4	302.3	294.1
Interest Expense, Net	105.5	104.4	98.4
Other (Expense) Income, Net	0.1	21.2	(8.0)
Income Before Income Taxes	101.0	219.1	187.7
Income Tax Expense (Benefit)	12.4	34.5	(26.5)
Net Income	88.6	184.6	214.2
Spire Missouri
Net Income	130.2	115.0	129.3
Defined benefit pension and other postretirement benefit plans:
Other Comprehensive (Loss) Income, Net of Tax	(0.5)	(0.8)	0.4
Comprehensive Income	129.7	114.2	129.7
Operating Revenues	1,193.6	1,291.8	1,285.6
Operating Expenses:
Natural gas	515.8	629.8	636.8
Operation and maintenance	251.0	268.1	279.1
Depreciation and amortization	118.0	111.5	102.8
Taxes, other than income taxes	103.2	107.6	108.4
Total Operating Expenses	988.0	1,117.0	1,127.1
Operating Income	205.6	174.8	158.5
Interest Expense, Net	49.4	49.2	46.4
Other (Expense) Income, Net	(8.7)	2.7	(15.4)
Income Before Income Taxes	147.5	128.3	96.7
Income Tax Expense (Benefit)	17.3	13.3	(32.6)
Net Income	$ 130.2	$ 115.0	$ 129.3