v3.25.2
Shareholder Report
6 Months Ended
Apr. 30, 2025
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name International Income Portfolio
Entity Central Index Key 0001394396
Entity Investment Company Type N-1A
Document Period End Date Apr. 30, 2025
C000049878  
Shareholder Report [Line Items]  
Fund Name International Income Portfolio
No Trading Symbol [Flag] true
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the International Income Portfolio (the "Fund") for the period of November 1, 2024 to April 30, 2025.
Shareholder Report Annual or Semi-Annual Semi-Annual Shareholder Report
Additional Information [Text Block] You can find additional information about the Fund at www.eatonvance.com/open-end-mutual-fund-documents.php and selecting Eaton Vance Global Sovereign Opportunities Fund. You can also request this information by contacting us at 1-800-262-1122.
Additional Information Phone Number 1-800-262-1122
Additional Information Website <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left; white-space-collapse: preserve-breaks;">www.eatonvance.com/open-end-mutual-fund-documents.php</span>
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Fund Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
International Income Portfolio
$48
0.94%Footnote Reference1
Footnote Description
Footnote1
Annualized
Expenses Paid, Amount $ 48
Expense Ratio, Percent 0.94% [1]
AssetsNet $ 32,883,777
Holdings Count | Holding 503
InvestmentCompanyPortfolioTurnover 102.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets
$32,883,777
# of Portfolio Holdings (including derivatives)
503
Portfolio Turnover Rate
102%
Holdings [Text Block]

Asset Allocation (% of total investments)

Group By Asset Type Chart
Value
Value
OtherFootnote Reference
0.7%
Collateralized Mortgage Obligations
7.4%
U.S. Government Agency Mortgage-Backed Securities
9.2%
Short-Term Investments
30.3%
Sovereign Government Bonds
52.4%
Footnote Description
Footnote
Investment types less than 1% each

Foreign Currency Exposure (% of net assets)Footnote Reference*

Euro
13.7%
Japan
12.5%
India
7.4%
Iceland
6.1%
Australia
5.9%
Serbia
5.7%
Taiwan
5.6%
Dominican Republic
5.3%
Singapore
4.5%
Other
22.1%
Total Long Exposure
88.8%
Malaysia
(4.5)%
Other
(10.0)%
Total Short Exposure
(14.5)%
Footnote Description
Footnote*
Currency exposures include all foreign exchange denominated assets and currency derivatives.
Material Fund Change [Text Block]
Updated Prospectus Phone Number 1-800-262-1122
[1] Annualized