Acquisition - Pro Forma Financial Information (Details) - Spire Marketing, Inc. - Boardwalk Pipelines, LP - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
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Sep. 30, 2026 |
Sep. 30, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
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| Business Combination, Pro Forma Information [Line Items] | ||||
| Operating revenue | $ 613.6 | $ 568.4 | $ 1,885.7 | $ 1,817.6 |
| Net income | $ 115.4 | $ 125.9 | 525.8 | $ 490.0 |
| Acquisition-related costs as of the beginning of the earliest period presented | $ 4.0 | |||
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- Definition Amount of acquisition-related costs that were recognized in earnings prior to the earliest period presented and therefore are reflected in the pro forma financial information adjustment disclosures. No definition available.
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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/exampleRef
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- Definition Amount, after tax, of pro forma income (loss) of combined entity as if acquisition date of business combination occurred as of beginning of period. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of pro forma revenue of combined entity as if acquisition date of business combination occurred as of beginning of period. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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