v3.21.2

Description of the Business (Details)		9 Months Ended
Description of the Business (Details)	Oct. 26, 2021 shares	Sep. 30, 2021 segment refinery
Property, Plant and Equipment [Line Items]
Number of reportable segments \| segment		1
Subsequent Event \| Merger With Phillips 66 Partners
Property, Plant and Equipment [Line Items]
Number of shares issued per acquiree share (in shares) \| shares	0.50
Conversion price of preferred units to common units, percent	147.50%
Phillips 66
Property, Plant and Equipment [Line Items]
Number of refineries \| refinery		9

Business Combination, Consideration Transferred, Equity Interests Issued And Issuable, Entity Shares Issued Per Acquiree Share

+ References

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- Definition

Number of refineries of parent supported by assets of the public traded master limited partnership

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- Definition

Partners' Capital, Preferred Units, Convertible, Conversion Premium, Percent

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8672-108599

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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.

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PHILLIPS 66 PARTNERS LP 10-Q