CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2019	Sep. 30, 2018
ASSETS
Non-utility property, accumulated depreciation and amortization	$ 12.7	$ 10.4
Capitalization:
Preferred stock, par value (in dollars per share)	$ 25.00
Preferred stock, depositary shares authorized (in shares)	10,000,000.0	5,000,000
Preferred stock, depositary shares outstanding (in shares)	10,000,000.0
Preferred stock, depositary shares issued (in shares)	10,000,000.0
Common stock, par value (in dollars per share)	$ 1.00	$ 1.00
Common stock, authorized (in shares)	70,000,000.0	70,000,000.0
Common stock, issued (in shares)	51,000,000.0	50,700,000
Common stock, outstanding (in shares)	51,000,000.0	50,700,000
Spire Missouri
Capitalization:
Preferred stock, depositary shares authorized (in shares)	1,480,000	1,480,000
Preferred stock, depositary shares outstanding (in shares)	0	0
Preferred stock, depositary shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 1.00	$ 1.00
Common stock, authorized (in shares)	50,000,000.0	50,000,000.0
Common stock, issued (in shares)	24,577	24,577
Common stock, outstanding (in shares)	24,577	24,577
Spire Alabama
Capitalization:
Preferred stock, depositary shares authorized (in shares)	120,000	120,000
Preferred stock, depositary shares outstanding (in shares)	0	0
Preferred stock, depositary shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	3,000,000	3,000,000
Common stock, issued (in shares)	1,972,052	1,972,052
Common stock, outstanding (in shares)	1,972,052	1,972,052