XML 66 R55.htm IDEA: XBRL DOCUMENT
v3.21.1

Derivatives and Risk Management Activities - Currency Exchange Rate Risk Hedging (Details) $ in Millions, $ in Millions | 3 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2021 USD ($) $ / $ | Mar. 31, 2020 USD ($) | Mar. 31, 2021 CAD ($) $ / $ | Dec. 31, 2020 USD ($)
Foreign Currency Derivatives | Derivatives Not Designated as a Hedge | Supply and Logistics segment revenues |  |  |  |
Currency Exchange Rate Risk Hedging: |  |  |  |
Gain/(loss) recognized in earnings | $ | $ 1 | $ (6) |  |
Forward exchange contracts that exchange CAD For USD maturing in 2021 |  |  |  |
Currency Exchange Rate Risk Hedging: |  |  |  |
Notional amount of derivatives | $ 167 |  | $ 210 |
Forward exchange contracts that exchange CAD For USD maturing in 2021 | Minimum |  |  |  |
Currency Exchange Rate Risk Hedging: |  |  |  |
Average exchange rate (cad per usd) | 1.00 |  | 1.00 |
Forward exchange contracts that exchange CAD For USD maturing in 2021 | Maximum |  |  |  |
Currency Exchange Rate Risk Hedging: |  |  |  |
Average exchange rate (cad per usd) | 1.25 |  | 1.25 |
Forward exchange contracts that exchange USD for CAD maturing in 2021 |  |  |  |
Currency Exchange Rate Risk Hedging: |  |  |  |
Notional amount of derivatives | $ 227 |  | $ 285 |
Forward exchange contracts that exchange USD for CAD maturing in 2021 | Minimum |  |  |  |
Currency Exchange Rate Risk Hedging: |  |  |  |
Average exchange rate (cad per usd) | 1.00 |  | 1.00 |
Forward exchange contracts that exchange USD for CAD maturing in 2021 | Maximum |  |  |  |
Currency Exchange Rate Risk Hedging: |  |  |  |
Average exchange rate (cad per usd) | 1.26 |  | 1.26 |
Interest Rate Derivatives | Derivatives in Hedging Relationships | Other current assets |  |  |  |
Currency Exchange Rate Risk Hedging: |  |  |  |
Derivative asset | $ | $ 1 |  |  | $ 2

X
- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 + Details
Name: | us-gaap_DerivativeAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Average contractual rate at which a foreign currency can be purchased or sold. + References No definition available. + Details
Name: | us-gaap_DerivativeAverageForwardExchangeRate1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959 + Details
Name: | us-gaap_DerivativeNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_ForeignCurrencyDerivativesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of foreign currency derivatives not designated as hedging instruments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5618551-113959 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624171-113959 + Details
Name: | us-gaap_GainLossOnForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=pagp_SalesAndRelatedRevenuesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=pagp_ForeignExchangeForwardContractsThatExchangeCanadianDollarsForUSDollarsAtAverageRateDisclosedMaturingIn2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=pagp_ForeignExchangeForwardContractsThatExchangeUSDollarsForCanadianDollarsAtAverageRateDisclosedMaturingIn2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_OtherCurrentAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |