Entity Central Index Key Document and entity information. Document And Entity Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Subscriptions receivable. Statement Of Financial Position [Abstract] Assets Assets [Abstract] Current Assets: Assets Current [Abstract] Japanese Yen deposits, interest bearing Interest Bearing Deposits In Banks Japanese Yen deposits, non-interest bearing Due From Banks Subscriptions Receivable Subscriptions Receivable Total Current Assets Assets Current Liabilities, Redeemable Capital Shares and Shareholders’ Equity Liabilities And Stockholders Equity [Abstract] Current Liabilities: Liabilities Current [Abstract] Accrued Sponsor’s fee Due To Related Parties Current Accrued interest expense on currency deposits Interest Payable Current Total Current Liabilities Liabilities Current Commitments and Contingent Liabilities (note 8) Commitments And Contingencies Redeemable Capital Shares, at redemption value, no par value, 76,000,000 and 69,000,000 authorized, respectively – 2,050,000 and 2,000,000 issued and outstanding, respectively Redeemable Noncontrolling Interest Equity Carrying Amount Shareholders’ Equity: Stockholders Equity [Abstract] Retained Earnings Retained Earnings Accumulated Deficit Total Liabilities, Redeemable Capital Shares and Shareholders’ Equity Liabilities And Stockholders Equity Redeemable Capital Shares, no par value Temporary Equity Par Or Stated Value Per Share Redeemable Capital Shares, shares authorized Temporary Equity Shares Authorized Redeemable Capital Shares, shares issued Temporary Equity Shares Issued Redeemable Capital Shares, shares outstanding Temporary Equity Shares Outstanding Statement Of Income And Comprehensive Income [Abstract] Income Revenues [Abstract] Interest Income Investment Income Interest Total Income Revenues Expenses Costs And Expenses [Abstract] Sponsor’s fee Sponsor Fees Interest Expense on currency deposits Interest Expense Total Expenses Operating Expenses Net Comprehensive Income (Loss) Net Income Loss Basic and Diluted Earnings per Share Earnings Per Share Basic And Diluted Weighted-average Shares Outstanding Weighted Average Number Of Share Outstanding Basic And Diluted Temporary Equity Stock Redeemed During Period Value New Issues Temporary equity period increase decrease due to share transactions. Temporary equity issue period increase or decrease related to retained earnings. Statement Of Stockholders Equity [Abstract] Statement [Table] Statement [Table] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Retained Earnings [Member] Retained Earnings [Member] Redeemable capital shares. Redeemable Capital Shares [Member] Redeemable Capital Shares [Member] Statement [Line Items] Statement [Line Items] Balance Stockholders Equity Including Portion Attributable To Noncontrolling Interest Purchases of Shares Stock Issued During Period Value New Issues Purchases of Shares Temporary Equity Stock Issued During Period Value New Issues Redemption of Shares Stock Redeemed Or Called During Period Value Redemption of Shares Temporary Equity Stock Redeemed During Period Value New Issues Net Increase (Decrease) due to Share Transactions Temporary Equity Period Increase Decrease Due To Share Transactions Distributions Dividends Common Stock Cash Net Comprehensive Income (Loss) Adjustment of Redeemable Capital Shares to Redemption Value related to Retained Earnings Temporary Equity Issue Period Increase Or Decrease Related To Retained Earnings Adjustment of Redeemable Capital Shares to Redemption Value Temporary Equity Issue Period Increase Or Decrease Balance Statement Of Cash Flows [Abstract] Cash flows from operating activities Net Cash Provided By Used In Operating Activities [Abstract] Adjustments to reconcile net comprehensive income (loss) to net cash provided by operating activities: Adjustments Noncash Items To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Accrued interest expense Increase Decrease In Interest Payable Net Accrued Sponsor’s fee Increase Decrease In Due To Related Parties Current Net cash used in operating activities Net Cash Provided By Used In Operating Activities Cash flows from financing activities Net Cash Provided By Used In Financing Activities [Abstract] Distributions paid to shareholders Distribution Made To Limited Partner Cash Distributions Paid Proceeds from purchases of redeemable Shares Proceeds From Issuance Of Redeemable Preferred Stock Redemptions of redeemable Shares Payments For Repurchase Of Redeemable Preferred Stock Net cash provided by financing activities Net Cash Provided By Used In Financing Activities Effect of exchange rate on cash Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Net change in cash Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect Cash at beginning of period Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Cash at end of period Accounting Policies [Abstract] Background Business Description And Basis Of Presentation [Text Block] Organization Consolidation And Presentation Of Financial Statements [Abstract] Organization and Description of the Trust Organization Consolidation And Presentation Of Financial Statements Disclosure [Text Block] Significant Accounting Policies Significant Accounting Policies [Text Block] Cash And Cash Equivalents [Abstract] Japanese Yen Deposits Cash And Cash Equivalents Disclosure [Text Block] Federal Home Loan Banks [Abstract] Redeemable Capital Shares Stockholders Equity Note Disclosure [Text Block] Related Party Transactions [Abstract] Related Parties Related Party Transactions Disclosure [Text Block] Risks And Uncertainties [Abstract] Concentration Risk Concentration Risk Disclosure [Text Block] Commitments And Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments And Contingencies Disclosure [Text Block] Use of Estimates Use Of Estimates Foreign Currency Translation Foreign Currency Transactions And Translations Policy [Text Block] Federal Income Taxes Income Tax Policy [Text Block] Revenue Recognition Revenue Recognition Policy [Text Block] Entire disclosure for dividends. Dividends Dividends Policy [Text Block] Schedule for Redeemable Capital Shares Activity Temporary Equity Table [Text Block] Initial incorporation deposit with bank sponsor. Date of Incorporation Entity Incorporation Date Of Incorporation Initial deposits by sponsor, primary deposit account Initial Incorporation Deposit With Bank Sponsor Number of deposits accounts in which trust assets primarily consist demand deposit. Stock redeemable number share each block shares. Number of deposits accounts in which trust's assets primarily consist of Japanese Yen Number Of Deposits Accounts In Which Trust Assets Primarily Consist Demand Deposit Redemptions capital shares, number of shares in each block Stock Redeemable In Baskets Number Of Shares Provision for federal income taxes Income Tax Expense Benefit Minimum Period Required To Stay For Tax Liability Number of days in United States for tax purposes Minimum Period Required To Stay For Tax Liability Principal deposits Principal redemptions Withdrawals (to pay expenses) Payments For Operating Activities Deposits, interest bearing Cash Annual nominal rate Investment Interest Rate Redeemable capital shares settlement period creation and redemption. Temporary Equity Disclosure [Abstract] Redeemable capital shares, settlement of each creation or redemption period Redeemable Capital Shares Settlement Period Creation And Redemption Temporary Equity Shares Issued During Period Temporary Equity Shares Redeemed During Period Opening Balance, Shares Shares Issued, Shares Temporary Equity Shares Issued During Period Shares Redeemed, Shares Temporary Equity Shares Redeemed During Period Ending Balance, Shares Opening Balance, Amount Shares Issued, Amount Adjustment of Redeemable Capital Shares to Redemption Value Temporary Equity Foreign Currency Translation Adjustments Ending Balance, Amount Schedule Of Related Party Transactions By Related Party [Table] Schedule Of Related Party Transactions By Related Party [Table] Related Party Related Party Transactions By Related Party [Axis] Related Party Related Party [Domain] Sponsor [Member] Sponsor [Member] Sponsor [Member] Related Party Transaction Related Party Transaction [Axis] Related Party Transaction Related Party Transaction [Domain] Accrued Professional Fees [Member] Accrued Professional Fees [Member] Accrued Professional Fees [Member] Professional Fees Liability [Member] Professional Fees Liability [Member] Professional Fees Liability [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Sponsor's fee accrues daily and paid monthly, annual nominal Rate Related Party Transaction Rate Legal fees and expenses assumed sponsor. Legal fees and expenses assumed Maximum Threshold Annual Amount Of Payments Legal Fees And Expenses Represents the minimum threshold for legal fees and expenses. Excess amount of assumed audit fees and legal expenses Minimum Threshold Excess Annual Amount Of Payments Legal Fees And Expenses