Additional Equity Method Ownership Interest Acquired

No definition available.

Name:	psx_AdditionalEquityMethodOwnershipInterestAcquired
Namespace Prefix:	psx_
Data Type:	num:percentItemType
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Period Type:	instant

- Definition

Amount representing the elimination of the previously held equity method investment balance after a step acquisition as well as the elimination of working capital balances with the business after consolidation.

+ References

No definition available.

+ Details

Name:	psx_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedEliminationOfEquityMethodInvestment
Namespace Prefix:	psx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of cash and cash equivalents restricted as to withdrawal or usage acquired at the acquisition date.

+ References

No definition available.

+ Details

Name:	psx_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedRestrictedCash
Namespace Prefix:	psx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

In a business combination achieved in stages, this element represents the amount of gain recognized by the entity as a result of remeasuring to fair value the equity interest in the acquiree it held before the business combination. Amount also includes the amount in a business combination in which the amount of net identifiable assets acquired and liabilities assumed exceeds the aggregate consideration transferred or to be transferred (as defined), this element represents the amount of gain recognized by the entity.

+ References

No definition available.

+ Details

Name:	psx_BusinessCombinationStepAcquisitionEquityInterestInAcquireeRemeasurementGainAndBargainPurchase
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage of ownership in subsidiary

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

The amount of financial liabilities assumed (as defined) which have been recognized as of the acquisition date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 55
-Paragraph 37
-URI http://asc.fasb.org/extlink&oid=116868840&loc=d3e2207-128464

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=116869197&loc=d3e4845-128472

+ Details

Name:	us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancialLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of property, plant, and equipment recognized as of the acquisition date.

+ References

+ Details

Name:	us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value at acquisition-date of the equity interest in the acquiree held by the acquirer, immediately before the acquisition date for businesses combined in stages.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (g)(1)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

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Balance Type:	credit
Period Type:	duration

- Details

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- Details

Name:	srt_CounterpartyNameAxis=psx_Phillips66PartnersLPMember
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- Details

Name:	us-gaap_RelatedPartyTransactionAxis=psx_CommonControlTransactionMember
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Business Combinations (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
Business Combinations (Details) - USD ($) $ in Millions	Feb. 28, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Oct. 31, 2017
Business Acquisition [Line Items]
Gain on consolidation of business			$ 0	$ 0	$ 423
Merey Sweeny L.P.
Business Acquisition [Line Items]
Additional equity method ownership interest acquired in MSLP, percent	50.00%
Gain on consolidation of business		$ 423
Step acquisition, equity interest in acquiree, fair value	$ 145
Restricted cash		318
PP&E provisionally recorded		250
Financial liabilities		238
Settlement adjustment		$ 93
Merey Sweeny L.P. \| Phillips 66 Partners LP \| Common Control Transaction
Business Acquisition [Line Items]
Percentage of ownership In subsidiary						100.00%