v3.26.1
Divestitures - Schedule of Income (Loss) from Discontinued Operations, Net of Tax (Details) - USD ($)
$ in Millions
1 Months Ended 3 Months Ended 9 Months Ended
Jun. 30, 2026
Apr. 30, 2026
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Disposal Group, Including Discontinued Operations [Line Items]            
Gain on Sale of Discontinued Operations, Net of Tax         $ 329.4 $ 0.0
Discontinued Operations, Held-for-Sale [Member]            
Disposal Group, Including Discontinued Operations [Line Items]            
Operating Revenues     $ 35.0 $ 69.4 194.2 195.4
Natural gas     11.5 7.7 41.9 64.6
Operation and maintenance     21.3 11.0 43.0 34.0
Depreciation and amortization     0.0 2.9 6.9 5.6
Taxes, other than income taxes     0.6 0.7 2.0 1.7
Total Operating Expenses     33.4 22.3 93.8 105.9
Operating (Loss) Income     1.6 47.1 100.4 89.5
Interest Expense, Net     2.6 2.0 6.6 5.9
(Loss) Income Before Income Taxes     (1.0) 45.1 93.8 83.6
Income Tax (Benefit) Expense     (0.2) 10.9 22.8 20.2
Net (Loss) Income     (0.8)   71.0  
Gain on Sale of Discontinued Operations, Net of Tax     254.6   254.6  
Net Income from discontinued operations attributable to Spire Inc.     253.8 34.2 325.6 63.4
Discontinued Operations, Held-for-Sale [Member] | Spire Marketing [Member]            
Disposal Group, Including Discontinued Operations [Line Items]            
Operating Revenues     8.9 43.1 118.0 129.7
Natural gas     11.5 7.7 41.9 64.6
Operation and maintenance     2.4 3.2 11.5 11.8
Depreciation and amortization     0.0 0.2 0.2 0.9
Taxes, other than income taxes     0.1 0.3 0.6 0.8
Total Operating Expenses     14.0 11.4 54.2 78.1
Operating (Loss) Income     5.1 31.7 63.8 51.6
Interest Expense, Net     0.0 0.0 0.0 0.0
(Loss) Income Before Income Taxes   $ 118.6 (5.1) 31.7 63.8 51.6
Income Tax (Benefit) Expense   $ 26.9 (1.3) 7.9 15.9 12.9
Net (Loss) Income     (3.8)   47.9  
Gain on Sale of Discontinued Operations, Net of Tax     91.7   91.7  
Net Income from discontinued operations attributable to Spire Inc.     87.9 23.8 139.6 38.7
Discontinued Operations, Held-for-Sale [Member] | Spire Storage [Member]            
Disposal Group, Including Discontinued Operations [Line Items]            
Operating Revenues     26.1 26.3 76.2 65.7
Natural gas     0.0 0.0 0.0 0.0
Operation and maintenance     18.9 7.8 31.5 22.2
Depreciation and amortization     0.0 2.7 6.7 4.7
Taxes, other than income taxes     0.5 0.4 1.4 0.9
Total Operating Expenses     19.4 10.9 39.6 27.8
Operating (Loss) Income     6.7 15.4 36.6 37.9
Interest Expense, Net     2.6 2.0 6.6 5.9
(Loss) Income Before Income Taxes $ 210.8   4.1 13.4 30.0 32.0
Income Tax (Benefit) Expense $ 47.9   1.1 3.0 6.9 7.3
Net (Loss) Income     3.0   23.1  
Gain on Sale of Discontinued Operations, Net of Tax     162.9   162.9  
Net Income from discontinued operations attributable to Spire Inc.     $ 165.9 $ 10.4 $ 186.0 $ 24.7