Summary of Significant Accounting Policies and Other Matters - Narrative (Details) - USD ($) $ in Millions |
1 Months Ended | 3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|---|
Apr. 30, 2026 |
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
Mar. 31, 2026 |
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| Schedule of Equity Method Investments [Line Items] | ||||||
| Anti-dilutive effect (shares) | 0 | 0 | 0 | 0 | ||
| Con Edison Gas Pipeline and Storage, LLC | ||||||
| Schedule of Equity Method Investments [Line Items] | ||||||
| Equity method investments | $ 5.0 | |||||
| Sale of other investments | $ 1.5 | |||||
| Mountain Valley Pipeline LLC | Con Edison Gas Pipeline and Storage, LLC | ||||||
| Schedule of Equity Method Investments [Line Items] | ||||||
| Equity method investment, ownership percent (in percent) | 6.60% | |||||
| Equity method investments | $ 357.5 | |||||
| Earnings from its equity investment | $ 7.0 | $ 15.0 | ||||
| Earnings from its equity investment, after tax | $ 5.0 | $ 11.0 | ||||
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- Definition Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of income (loss) for proportionate share of equity method investee's income (loss). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount, after tax, of other comprehensive income (loss) (OCI) for proportionate share of equity method investee's OCI. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The cash inflow associated with the sale of equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of cash inflow from the sale of investments classified as other. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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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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