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Related Party Transactions - Summary of Classification of Charges between Operating and Maintenance Expenses and General and Administrative Expenses (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Related Party Transaction [Line Items]
Operating and maintenance expenses	$ 94.1	$ 87.5	$ 179.7	$ 165.6
Hess
Related Party Transaction [Line Items]
Operating and maintenance expenses	$ 25.0	$ 20.5	$ 49.9	$ 39.6
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General and administrative expenses	$ 5.3	$ 3.5	$ 10.3	$ 7.0
Selling, General, and Administrative Expenses, Related Party [Extensible Enumeration]	us-gaap:RelatedPartyMember	us-gaap:RelatedPartyMember	us-gaap:RelatedPartyMember	us-gaap:RelatedPartyMember
Total	$ 30.3	$ 24.0	$ 60.2	$ 46.6

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Indicates status and type of related party for cost and expense classified as operating.

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Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Excludes Selling, General and Administrative Expense.

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Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense.

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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.

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The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

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