Name:	gpff_DepositsWithBrokerDealersLineItems
Namespace Prefix:	gpff_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The fair value, as of the balance sheet date, of financial instruments owned by the entity and pledged to counterparties as collateral. Excludes derivative contracts.

No definition available.

Name:	gpff_FinancialInstrumentsExcludingDerivativesOwnedAndPledgedAsCollateralAtFairValue
Namespace Prefix:	gpff_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Securities owned and pledged as collateral to satisfy margin requirements with broker-dealers as a percent of net asset value.

No definition available.

Name:	gpff_FinancialInstrumentsOwnedAndPledgedAsCollateralAtFairValuePercentOfNetAssetValue
Namespace Prefix:	gpff_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the high end of the range of percentage of net asset value that is required to maintain as margin and good faith deposits with broker-dealers.

No definition available.

Name:	gpff_MarginAndGoodFaithDepositsWithBrokerDealersPercentageOfNetAssetValueHighEndOfRange
Namespace Prefix:	gpff_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the low end of the range of percentage of net asset value that is required to maintain as margin and good faith deposits with broker-dealers.

No definition available.

Name:	gpff_MarginAndGoodFaithDepositsWithBrokerDealersPercentageOfNetAssetValueLowEndOfRange
Namespace Prefix:	gpff_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682