Shareholder Report, Holdings (Details) - C000049878	Apr. 30, 2025
CurrencyExposure_Long_Other
Holdings [Line Items]
Percent of Net Long Exposure	22.10%
Short_Currency_TotalTotal Short Exposure
Holdings [Line Items]
Percent of Total Short Exposure	(14.50%)
CurrencyExposure_Long_Euro
Holdings [Line Items]
Percent of Net Long Exposure	13.70%
CurrencyExposure_Long_Japan
Holdings [Line Items]
Percent of Net Long Exposure	12.50%
CurrencyExposure_Long_India
Holdings [Line Items]
Percent of Net Long Exposure	7.40%
CurrencyExposure_Long_Iceland
Holdings [Line Items]
Percent of Net Long Exposure	6.10%
CurrencyExposure_Long_Australia
Holdings [Line Items]
Percent of Net Long Exposure	5.90%
CurrencyExposure_Long_Serbia
Holdings [Line Items]
Percent of Net Long Exposure	5.70%
CurrencyExposure_Long_Taiwan
Holdings [Line Items]
Percent of Net Long Exposure	5.60%
CurrencyExposure_Long_Dominican Republic
Holdings [Line Items]
Percent of Net Long Exposure	5.30%
CurrencyExposure_Long_Singapore
Holdings [Line Items]
Percent of Net Long Exposure	4.50%
Long_Currency_TotalTotal Long Exposure
Holdings [Line Items]
Percent of Total Long Exposure	88.80%
CurrencyExposure_Short_Malaysia
Holdings [Line Items]
Percent of Net Short Exposure	(4.50%)
CurrencyExposure_Short_Other
Holdings [Line Items]
Percent of Net Short Exposure	(10.00%)
AssetCollateralized Mortgage Obligations
Holdings [Line Items]
Percent of Total Investments	7.40%
AssetU.S. Government Agency Mortgage-Backed Securities
Holdings [Line Items]
Percent of Total Investments	9.20%
AssetShort-Term Investments
Holdings [Line Items]
Percent of Total Investments	30.30%
AssetSovereign Government Bonds
Holdings [Line Items]
Percent of Total Investments	52.40%

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form N-1A
-Section 27A
-Subsection f

Name:	oef_HoldingsLineItems
Namespace Prefix:	oef_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form N-1A
-Section 27A
-Subsection f

+ Details

Name:	oef_PctOfNetLongExposure
Namespace Prefix:	oef_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form N-1A
-Section 27A
-Subsection f

+ Details

Name:	oef_PctOfNetShortExposure
Namespace Prefix:	oef_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form N-1A
-Section 27A
-Subsection f

+ Details

Name:	oef_PctOfTotalInv
Namespace Prefix:	oef_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form N-1A
-Section 27A
-Subsection f

+ Details

Name:	oef_PctOfTotalLongExposure
Namespace Prefix:	oef_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form N-1A
-Section 27A
-Subsection f

+ Details

Name:	oef_PctOfTotalShortExposure
Namespace Prefix:	oef_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	oef_ClassAxis=eatonvance_C000049878Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	oef_OtherCategory2Axis=eatonvance_CurrencyExposureLongOtherCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	oef_OtherCategory2Axis=eatonvance_ShortCurrencyTotalTotalShortExposureCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	oef_OtherCategory1Axis=eatonvance_CurrencyExposureLongEuroCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	oef_OtherCategory1Axis=eatonvance_CurrencyExposureLongJapanCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	oef_OtherCategory1Axis=eatonvance_CurrencyExposureLongIndiaCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	oef_OtherCategory1Axis=eatonvance_CurrencyExposureLongIcelandCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	oef_OtherCategory1Axis=eatonvance_CurrencyExposureLongAustraliaCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	oef_OtherCategory1Axis=eatonvance_CurrencyExposureLongSerbiaCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	oef_OtherCategory1Axis=eatonvance_CurrencyExposureLongTaiwanCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	oef_OtherCategory1Axis=eatonvance_CurrencyExposureLongDominicanRepublicCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	oef_OtherCategory1Axis=eatonvance_CurrencyExposureLongSingaporeCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	oef_OtherCategory1Axis=eatonvance_LongCurrencyTotalTotalLongExposureCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	oef_OtherCategory1Axis=eatonvance_CurrencyExposureShortMalaysiaCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	oef_OtherCategory1Axis=eatonvance_CurrencyExposureShortOtherCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=eatonvance_AssetCollateralizedMortgageObligationsCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=eatonvance_AssetUSGovernmentAgencyMortgageMinusBackedSecuritiesCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=eatonvance_AssetShortMinusTermInvestmentsCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=eatonvance_AssetSovereignGovernmentBondsCTIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: