v3.26.1
CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - USD ($)
$ in Millions
Mar. 31, 2026
Sep. 30, 2025
Mar. 31, 2025
Non-utility property, accumulated depreciation and amortization $ 118.6 $ 106.6 $ 94.6
Common stock, par value (in dollars per share) $ 1 $ 1 $ 1
Common stock, shares authorized (in shares) 70,000,000 70,000,000 70,000,000
Common stock, shares issued (in shares) 59,100,000 59,000,000 59,000,000
Common stock, shares outstanding (in shares) 59,100,000 59,000,000 59,000,000
Depositary Shares [Member]      
Preferred stock, par value (in dollars per share) $ 25 $ 25 $ 25
Preferred stock, shares authorized (in shares) 10,000,000 10,000,000 10,000,000
Preferred stock, shares issued (in shares) 10,000,000 10,000,000 10,000,000
Preferred stock, shares outstanding (in shares) 10,000,000 10,000,000 10,000,000
Spire Missouri [Member]      
Common stock, par value (in dollars per share) $ 1 $ 1 $ 1
Common stock, shares authorized (in shares) 50,000,000 50,000,000 50,000,000
Common stock, shares issued (in shares) 26,822 26,822 26,822
Common stock, shares outstanding (in shares) 26,822 26,822 26,822
Spire Alabama Inc [Member]      
Common stock, par value (in dollars per share) $ 0.01 $ 0.01 $ 0.01
Common stock, shares authorized (in shares) 3,000,000 3,000,000 3,000,000
Common stock, shares issued (in shares) 2,000,000 2,000,000 2,000,000
Common stock, shares outstanding (in shares) 2,000,000 2,000,000 2,000,000