1001 - Document - Cover Page link:presentationLink link:definitionLink link:calculationLink 1002 - Statement - Statements of Cash Receipts and Disbursements link:presentationLink link:definitionLink link:calculationLink 1003 - Statement - Statements of Cash Receipts and Disbursements (Parenthetical) link:presentationLink link:definitionLink link:calculationLink 999001 - Disclosure - Accounting Policies and General Information link:presentationLink link:definitionLink link:calculationLink 999002 - Disclosure - Federal Income Taxes link:presentationLink link:definitionLink link:calculationLink 999003 - Disclosure - Related Party Transactions link:presentationLink link:definitionLink link:calculationLink 999004 - Disclosure - The Copyright Catalogue link:presentationLink link:definitionLink link:calculationLink 999005 - Disclosure - Segment Information link:presentationLink link:definitionLink link:calculationLink 999006 - Disclosure - Other Matters link:presentationLink link:definitionLink link:calculationLink 999007 - Disclosure - Accounting Policies and General Information (Policies) link:presentationLink link:definitionLink link:calculationLink 999008 - Disclosure - Accounting Policies and General Information (Tables) link:presentationLink link:definitionLink link:calculationLink 999009 - Disclosure - Related Party Transactions (Tables) link:presentationLink link:definitionLink link:calculationLink 999010 - Disclosure - Accounting Policies and General Information - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999011 - Disclosure - Accounting Policies and General Information - Schedule of Contingent Portion Payments (Detail) link:presentationLink link:definitionLink link:calculationLink 999012 - Disclosure - Federal Income Taxes - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999013 - Disclosure - Related Party Transactions - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999014 - Disclosure - Related Party Transactions - Disbursements to Trustees (Detail) link:presentationLink link:definitionLink link:calculationLink 999015 - Disclosure - The Copyright Catalogue - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 999016 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure link:presentationLink link:definitionLink link:calculationLink Cover [Abstract] Amendment Flag Amendment Flag Auditor Firm ID Auditor Location Auditor Name City Area Code Current Fiscal Year End Date Current Fiscal Year End Date Document Annual Report Document Financial Statement Error Correction [Flag] Document Fiscal Period Focus Document Fiscal Period Focus Document Fiscal Year Focus Document Fiscal Year Focus Document Period End Date Document Period End Date Document Transition Report Document Type Document Type Entity Address, Address Line One Entity Address, Address Line Two Entity Address, City or Town Entity Address, Postal Zip Code Entity Address, State or Province Entity Central Index Key Entity Central Index Key Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Current Reporting Status Entity Current Reporting Status Entity Emerging Growth Company Entity Emerging Growth Company Entity File Number Entity Filer Category Entity Filer Category Entity Incorporation, State or Country Code Entity Interactive Data Current Entity Interactive Data Current Entity Public Float Entity Public Float Entity Registrant Name Entity Registrant Name Entity Shell Company Entity Shell Company Entity Small Business Entity Small Business Entity Tax Identification Number Entity Voluntary Filers Entity Voluntary Filers Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Local Phone Number Operating Cash Flows, Direct Method [Abstract] Cash Undistributed Cash at Beginning of Year Undistributed Cash at End of Year Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Balance Available for Distribution Cash Distribution Per Unit Cash Distributions Per Unit (based on 277,712 Trust Units Outstanding) Distributions per Unit Cash distribution per Trust Unit based on number Trust Units outstanding. Cash Distributions To Unit Holders Cash Distributions to Unit Holders Cash distributions to Unit Holders. General And Administrative Cash Outflow Disbursements – Administrative Expenses General and administrative cash outflow. Proceeds From Contingent Portion Payments Receipts from EMI Proceeds from Contingent Portion payments attributable to royalty income generated by the Catalogue. Statement [Table] Asset Class [Axis] Asset Class [Domain] Asset, Held-in-Trust [Member] Statement [Line Items] Number Of Common Units Outstanding Number of Trust Units Outstanding Number of Trust Units Outstanding. Proceeds from Legal Settlements Proceeds from Legal Settlements Accounting Policies [Abstract] Accounting Policies and General information Accounting Policies and General Information Income Tax Disclosure [Abstract] Income Tax Disclosure [Text Block] Federal Income Taxes Related Party Transactions [Abstract] Related Party Transactions Disclosure [Text Block] Related Party Transactions Text Block [Abstract] Revenue Recognition From Royalty Disclosure [Text Block] The Copyright Catalogue Copyright Catalogue Matters. Segment Reporting [Abstract] Segment Reporting Disclosure [Text Block] Segment Information Other Matters [Text Block] Other Matters Other Matters [Text Block] Basis of Accounting, Policy [Policy Text Block] Accounting Policies Cash Distributions To Unit Holders Policy [Policy Text Block] Cash Distributions to Unit Holders Cash distributions to Unit Holders. Contingent Portion Payments Policy Text Block. Contingent Portion Payments Contingent portion payments. New Accounting Pronouncements, Policy [Policy Text Block] Recent Accounting Pronouncements Organization And Background [Policy Text Block] Organization and Background Organization and background. Proceeds From Contingent Portion Payments Policy [Policy Text Block] Proceeds from Contingent Portion Payments Proceeds from Contingent Portion Payments. Recent Audit Settlement Payment Recent Audit Settlement Payment Recent Audit Settlement Payment Trust Expenses and Unit Holder Distributions [Policy Text Block] Unit Holder Distributions and Trust Expenses Trust Expenses and Unit Holder Distributions. Schedule of Deficiency for Contingent Consideration [Table Text Block] Schedule of Contingent Portion Payments Schedule of Deficiency for Contingent Consideration Table [Text Block] Schedule of Related Party Transactions [Table Text Block] Disbursements to Trustees Organization And Summary Of Significant Accounting Policies [Table] Organization And Summary Of Significant Accounting Policies [Table] Organization And Summary Of Significant Accounting Policies [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Litigation Status [Axis] Litigation Status [Domain] Organization And Summary Of Significant Accounting Policies [Line Items] Organization And Summary Of Significant Accounting Policies [Line Items] Organization And Summary Of Significant Accounting Policies [Line Items] Amount Of Payment To The Trust Amount Of Payment To The Trust Amount Of Payment To The Trust. Contingent Portion Payable Equal To Gross Royalty Income Percent Percentage of Contingent Portion of gross royalty income Calculation percentage for Contingent Portion formula. Entity Incorporation, Date of Incorporation Date of formation of Mills Music Trust Minimum Payment Of Quarterly Contingent Portion Minimum payment of quarterly Contingent Portion Minimum payment of quarterly contingent portion. Percentage Of EMI On Foreign Affiliate Maximum Percentage Deduction By EMI on Foreign Affiliate Sub-Publishing Fees Percentage Of EMI On Foreign Affiliate. Unpaid Expenses For Services Unpaid administrative expenses for services Unpaid expenses for services. Range [Axis] Range [Axis] Range [Domain] Range [Domain] Maximum [Member] Maximum [Member] Minimum [Member] Minimum [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Amount Of Deficiency For Contingent Consideration Deficiency in Contingent Portion payments Amount of deficiency for contingent consideration portion payments. Income Tax Expense (Benefit) Provision for income taxes Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Trustee Fees Trustee Annual Compensation Trustee annual compensation Amount of annual compensation for each Trustee's services, provided that such aggregate compensation to the Trustees as a group may not exceed a certain percentage of the Contingent Portion Payments received by the Trust in any year. Aggregate Compensation Percentage To Trustee Aggregate compensation percentage to Trustees Percentage of Contingent Portion Payments received by the Trust in any year which may not be exceeded as an amount of aggregate compensation to the Trustees as a group. Trustee Fees Trustee Fees and Expenses Legal Entity of Counterparty, Type [Axis] Legal Entity of Counterparty, Type [Axis] Legal Entity Type of Counterparty [Domain] Legal Entity Type of Counterparty [Domain] Individual Counterparty [Member] Individual Trustee Fees [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Corporate Trustee [Member] Corporate Trustee [Member] Corporate Trustee. Corporate Trustee Transfer Agent Registrar Fees [Member] Corporate Trustee Transfer Agent Registrar Fees [Member] Corporate Trustee Transfer Agent Registrar Fees [Member] Goodwill and Intangible Assets Disclosure [Abstract] Royalties Receivable [Table] Royalties Receivable [Table] Royalties Receivable [Table] Two Thousand Twenty Two Listing E M I Top Fifty Catalogue [Member] 2022 Listing Top 50 [Member] 2022 listing EMI top 50 catalogue. Royalties Receivable [Line Items] Royalties Receivable [Line Items] Royalties Receivable [Line Items] Copyright Protection Expiration Period Copyright protection expiration period The Copyright expiration dates for the catalogue. Estimated Number Of Songs In Catalogue Estimated number of songs in the Catalogue Estimated number of songs in the Catalogue. Estimated Number of Songs Producing Royalty Income Estimated number of songs producing royalty income Estimated number of songs producing royalty income. Number Of Songs Obtained Copyright Registration Number of Copyrighted Songs in the Top 50 list Number of top earning songs in the catalogue that obtained copyright registration, together with certain copyright information. Period Of Copyright Protection Period of copyright protection Songs that obtained copyright registration under the United States Copyright Act of 1909 (the "1909 Act") between 1922 and 1958. For copyrighted works subject to the 1909 Act, copyright law generally provides the number of years of copyright protection, subject to certain factors, including the initial registration date of each copyright and compliance with certain statutory provisions including notice and renewal.