Name:	pagp_InitialMargin
Namespace Prefix:	pagp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Cash posted by (returned to) the reporting entity to (from) a broker or counterparty to comply with initial margin requirements.

No definition available.

Name:	pagp_VariationMarginPostedReturned
Namespace Prefix:	pagp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of obligation to return cash collateral under master netting arrangements offset against derivative assets.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=126966630&loc=d3e41228-113958

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

Amount of right to receive cash collateral under master netting arrangements offset against derivative liabilities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=126966630&loc=d3e41228-113958

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

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

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.

Name:	us-gaap_DerivativesFairValueLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

No definition available.