Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Millions |
Total |
Common Stock [Member] |
Preferred Stock [Member] |
Additional Paid-in Capital [Member] |
Retained Earnings [Member] |
AOCI Attributable to Parent [Member] |
[1] | Spire Missouri [Member] |
Spire Missouri [Member]
Common Stock [Member]
|
Spire Missouri [Member]
Additional Paid-in Capital [Member]
|
Spire Missouri [Member]
Retained Earnings [Member]
|
Spire Missouri [Member]
AOCI Attributable to Parent [Member]
|
[2] | Spire Alabama Inc [Member] |
Spire Alabama Inc [Member]
Common Stock [Member]
|
Spire Alabama Inc [Member]
Additional Paid-in Capital [Member]
|
Spire Alabama Inc [Member]
Retained Earnings [Member]
|
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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Balance (in shares) at Sep. 30, 2023 | 53,170,224 | 25,855 | 1,972,052 | ||||||||||||||||||
| Balance at Sep. 30, 2023 | $ 2,917.3 | $ 53.2 | $ 242.0 | $ 1,616.5 | $ 958.0 | $ 47.6 | $ 1,844.8 | $ 0.1 | $ 854.8 | $ 992.4 | $ (2.5) | $ 928.0 | $ 285.9 | $ 642.1 | |||||||
| Net Income (Loss) | 276.8 | 276.8 | 145.4 | 145.4 | 84.7 | 84.7 | |||||||||||||||
| Common stock issued (in shares) | 4,490,282 | ||||||||||||||||||||
| Common stock issued | 286.0 | $ 4.4 | 281.6 | ||||||||||||||||||
| Dividend reinvestment plan (in shares) | 19,811 | ||||||||||||||||||||
| Dividend reinvestment plan | 1.2 | 1.2 | |||||||||||||||||||
| Stock-based compensation costs | 3.8 | 3.8 | |||||||||||||||||||
| Stock activity under stock-based compensation plans (in shares) | 89,834 | ||||||||||||||||||||
| Stock activity under stock-based compensation plans | $ 0.1 | (0.1) | |||||||||||||||||||
| Employees’ tax withholding for stock-based compensation (in shares) | (24,662) | ||||||||||||||||||||
| Employees’ tax withholding for stock-based compensation | (1.5) | (1.5) | |||||||||||||||||||
| Temporary equity adjustment to redemption value | (1.1) | (1.1) | |||||||||||||||||||
| Return of capital to Spire | (6.5) | (6.5) | |||||||||||||||||||
| Common stock | (129.2) | (129.2) | (42.9) | (42.9) | |||||||||||||||||
| Preferred stock | (11.1) | (11.1) | |||||||||||||||||||
| Other comprehensive income (loss), net of tax | (9.0) | (9.0) | 1.0 | 1.0 | |||||||||||||||||
| Balance (in shares) at Jun. 30, 2024 | 57,745,489 | 25,855 | 1,972,052 | ||||||||||||||||||
| Balance at Jun. 30, 2024 | 3,333.2 | $ 57.7 | 242.0 | 1,901.5 | 1,093.4 | 38.6 | 1,991.2 | $ 0.1 | 854.8 | 1,137.8 | (1.5) | 963.3 | 279.4 | 683.9 | |||||||
| Balance (in shares) at Mar. 31, 2024 | 57,741,692 | 25,855 | 1,972,052 | ||||||||||||||||||
| Balance at Mar. 31, 2024 | 3,390.3 | $ 57.7 | 242.0 | 1,899.7 | 1,155.3 | 35.6 | 2,007.1 | $ 0.1 | 854.8 | 1,154.6 | (2.4) | 966.9 | 279.4 | 687.5 | |||||||
| Net Income (Loss) | (12.6) | (12.6) | (16.8) | (16.8) | 2.9 | 2.9 | |||||||||||||||
| Dividend reinvestment plan (in shares) | 6,600 | ||||||||||||||||||||
| Dividend reinvestment plan | 0.4 | 0.4 | |||||||||||||||||||
| Stock-based compensation costs | 1.4 | 1.4 | |||||||||||||||||||
| Stock activity under stock-based compensation plans (in shares) | (2,682) | ||||||||||||||||||||
| Employees’ tax withholding for stock-based compensation (in shares) | (121) | ||||||||||||||||||||
| Temporary equity adjustment to redemption value | 0.3 | 0.3 | |||||||||||||||||||
| Common stock | (45.9) | (45.9) | (6.5) | (6.5) | |||||||||||||||||
| Preferred stock | (3.7) | (3.7) | |||||||||||||||||||
| Other comprehensive income (loss), net of tax | 3.0 | 3.0 | 0.9 | 0.9 | |||||||||||||||||
| Balance (in shares) at Jun. 30, 2024 | 57,745,489 | 25,855 | 1,972,052 | ||||||||||||||||||
| Balance at Jun. 30, 2024 | 3,333.2 | $ 57.7 | 242.0 | 1,901.5 | 1,093.4 | 38.6 | 1,991.2 | $ 0.1 | 854.8 | 1,137.8 | (1.5) | 963.3 | 279.4 | 683.9 | |||||||
| Balance (in shares) at Sep. 30, 2024 | 57,749,667 | 25,855 | 1,972,052 | ||||||||||||||||||
| Balance at Sep. 30, 2024 | 3,232.7 | $ 57.7 | 242.0 | 1,902.2 | 1,018.7 | 12.1 | 1,963.7 | $ 0.1 | 854.8 | 1,110.8 | (2.0) | 948.3 | 279.4 | 668.9 | |||||||
| Net Income (Loss) | 311.5 | 311.5 | 153.3 | 153.3 | 90.2 | 90.2 | |||||||||||||||
| Common stock issued (in shares) | 1,206,134 | 967 | |||||||||||||||||||
| Common stock issued | 74.8 | $ 1.2 | 73.6 | 74.4 | 74.4 | ||||||||||||||||
| Dividend reinvestment plan (in shares) | 17,039 | ||||||||||||||||||||
| Dividend reinvestment plan | 1.2 | 1.2 | |||||||||||||||||||
| Stock-based compensation costs | 4.2 | 4.2 | |||||||||||||||||||
| Stock activity under stock-based compensation plans (in shares) | 72,801 | ||||||||||||||||||||
| Stock activity under stock-based compensation plans | $ 0.1 | (0.1) | |||||||||||||||||||
| Employees’ tax withholding for stock-based compensation (in shares) | (25,317) | ||||||||||||||||||||
| Employees’ tax withholding for stock-based compensation | (1.9) | (1.9) | |||||||||||||||||||
| Temporary equity adjustment to redemption value | (1.1) | (1.1) | |||||||||||||||||||
| Return of capital to Spire | (36.5) | (36.5) | |||||||||||||||||||
| Common stock | (138.5) | (138.5) | (14.0) | (14.0) | |||||||||||||||||
| Preferred stock | (11.1) | (11.1) | |||||||||||||||||||
| Other comprehensive income (loss), net of tax | 8.4 | 8.4 | 0.7 | 0.7 | |||||||||||||||||
| Balance (in shares) at Jun. 30, 2025 | 59,020,324 | 26,822 | 1,972,052 | ||||||||||||||||||
| Balance at Jun. 30, 2025 | 3,480.2 | $ 59.0 | 242.0 | 1,979.2 | 1,179.5 | 20.5 | 2,192.1 | $ 0.1 | 929.2 | 1,264.1 | (1.3) | 988.0 | 242.9 | 745.1 | |||||||
| Balance (in shares) at Mar. 31, 2025 | 59,014,597 | 26,822 | 1,972,052 | ||||||||||||||||||
| Balance at Mar. 31, 2025 | 3,508.7 | $ 59.0 | 242.0 | 1,977.4 | 1,207.6 | 22.7 | 2,205.0 | $ 0.1 | 929.2 | 1,277.1 | (1.4) | 990.0 | 249.4 | 740.6 | |||||||
| Net Income (Loss) | 20.9 | 20.9 | (13.0) | (13.0) | 4.5 | 4.5 | |||||||||||||||
| Dividend reinvestment plan (in shares) | 5,073 | ||||||||||||||||||||
| Dividend reinvestment plan | 0.4 | 0.4 | |||||||||||||||||||
| Stock-based compensation costs | 1.4 | 1.4 | |||||||||||||||||||
| Stock activity under stock-based compensation plans (in shares) | 708 | ||||||||||||||||||||
| Employees’ tax withholding for stock-based compensation (in shares) | (54) | ||||||||||||||||||||
| Temporary equity adjustment to redemption value | 1.2 | 1.2 | |||||||||||||||||||
| Return of capital to Spire | (6.5) | (6.5) | |||||||||||||||||||
| Common stock | (46.5) | (46.5) | |||||||||||||||||||
| Preferred stock | (3.7) | (3.7) | |||||||||||||||||||
| Other comprehensive income (loss), net of tax | (2.2) | (2.2) | 0.1 | 0.1 | |||||||||||||||||
| Balance (in shares) at Jun. 30, 2025 | 59,020,324 | 26,822 | 1,972,052 | ||||||||||||||||||
| Balance at Jun. 30, 2025 | $ 3,480.2 | $ 59.0 | $ 242.0 | $ 1,979.2 | $ 1,179.5 | $ 20.5 | $ 2,192.1 | $ 0.1 | $ 929.2 | $ 1,264.1 | $ (1.3) | $ 988.0 | $ 242.9 | $ 745.1 | |||||||
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