Related Party Transactions (Narrative) (Details) $ in Millions	6 Months Ended
Jun. 30, 2020 USD ($)
Gray Oak Pipeline, LLC
Related Party Transaction [Line Items]
Effective ownership interest (as a percent)	42.25%
Phillips 66 \| Phillips 66 \| Amended Omnibus Agreement
Related Party Transaction [Line Items]
Monthly operational and administrative support fee	$ 8

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.

No definition available.

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