Acquisition Narrative (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
Apr. 30, 2026 |
Sep. 30, 2026 |
Sep. 30, 2026 |
Sep. 30, 2025 |
Dec. 31, 2025 |
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| Business Acquisition [Line Items] | |||||
| Payments to acquire businesses, net of cash acquired | $ 205.7 | $ 0.0 | |||
| Assets held for sale | $ 17.0 | 17.0 | $ 0.0 | ||
| Spire Marketing, Inc. | Boardwalk Pipelines, LP | |||||
| Business Acquisition [Line Items] | |||||
| Percentage of voting interests acquired | 100.00% | ||||
| Payments to acquire businesses, net of cash acquired | $ 205.7 | 205.7 | |||
| Acquisition, operating revenue contribution | 26.4 | 44.1 | |||
| Acquisition, net loss contribution | 18.3 | 19.9 | |||
| Acquisition-related costs | $ 0.1 | $ 3.9 | |||
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount classified as assets attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Percentage of voting equity interest acquired in business combination. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of expense for acquisition-related cost incurred to effect business combination. Includes, but is not limited to, finder's fee; advisory, legal, accounting, valuation, and other professional and consulting fees; and general administrative cost, including cost of maintaining internal acquisition department. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of acquiree's earnings (loss) since acquisition date of business combination included in consolidated statement of income. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of acquiree's revenue since acquisition date of business combination included in consolidated statement of income. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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