CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Net Income	$ 184.6	$ 214.2	$ 161.6
Cash flow hedging derivative instruments:
Net hedging (loss) gain arising during the period	(46.4)	3.9	11.5
Amounts reclassified into net income	(1.3)	(1.5)
Net (loss) gain on cash flow hedging derivative instruments	(47.7)	2.4	11.5
Defined benefit pension and other postretirement benefit plans:
Amortization of actuarial (gain) loss included in net periodic pension and postretirement benefit cost	(0.9)	0.4	0.4
Net defined benefit pension and other postretirement benefit plans	(0.9)	0.4	0.4
Net unrealized gain (loss) on available-for-sale debt securities	0.1	0.3	(0.1)
Other Comprehensive (Loss) Income, Before Tax	(48.5)	3.1	11.8
Income Tax (Benefit) Expense Related to Items of Other Comprehensive (Loss) Income	(10.8)	0.6	4.4
Other Comprehensive (Loss) Income, Net of Tax	(37.7)	2.5	7.4
Comprehensive Income	146.9	216.7	169.0
Operating Revenues:
Gas Utility	1,859.2	1,888.0	1,660.0
Total Operating Revenues	1,952.4	1,965.0	1,740.7
Gas Utility
Natural and propane gas	698.2	770.1	570.5
Other operation and maintenance expenses	432.3	441.2	385.8
Depreciation and amortization	179.4	167.0	153.5
Taxes, other than income taxes	151.7	152.5	137.8
Total Operating Expenses	1,650.1	1,670.9	1,399.8
Operating Income	302.3	294.1	340.9
Interest Expense, Net	104.4	98.4	89.1
Other Income (Expense), Net	21.2	(8.0)	(12.6)
Income Before Income Taxes	219.1	187.7	239.2
Income Tax Expense (Benefit)	34.5	(26.5)	77.6
Net Income	184.6	214.2	161.6
Spire Missouri
Net Income	115.0	129.3	113.0
Defined benefit pension and other postretirement benefit plans:
Other Comprehensive (Loss) Income, Net of Tax	(0.8)	0.4	0.1
Comprehensive Income	114.2	129.7	113.1
Operating Revenues:
Gas Utility	1,291.8	1,285.6	1,171.9
Total Operating Revenues	1,291.8	1,285.6	1,171.9
Gas Utility
Natural and propane gas	629.8	636.8	538.3
Other operation and maintenance expenses	268.1	279.1	226.6
Depreciation and amortization	111.5	102.8	93.1
Taxes, other than income taxes	107.6	108.4	99.8
Total Operating Expenses	1,117.0	1,127.1	957.8
Operating Income	174.8	158.5	214.1
Interest Expense, Net	49.2	46.4	39.1
Other Income (Expense), Net	2.7	(15.4)	(14.5)
Income Before Income Taxes	128.3	96.7	160.5
Income Tax Expense (Benefit)	13.3	(32.6)	47.5
Net Income	$ 115.0	$ 129.3	$ 113.0