Organization And Summary Of Significant Accounting Policies [Line Items]

Minimum payment of quarterly Contingent Portion

$ 167,500

EMI has provided the Trust with a listing of the top 50 earning songs in the Catalogue during the 2025 calendar year (the “Top 50 Songs”), together with certain copyright information with respect to each of the Top 50 Songs (the “Listing”). A copy of the Listing, as provided by EMI, is included in the Trust’s annual report on Form 10-K for the fiscal year ended December 31, 2025. The Listing does not include any information regarding Copyrighted Songs for the 2026 calendar year.

Distribution to Unit Holders per trust unit | $ / shares

$ 1.527

Distribution to Unit Holders per trust unit | $ / shares

$ 0.8133

$ 0.8701

Distribution to Unit Holders per trust unit | $ / shares

$ 0.3333

Distribution to Unit Holders per trust unit | $ / shares

$ 0.3239

Distributions to Unit Holders

$ 93,323

$ 345,295

Percentage of Contingent Portion of gross royalty income

65.00%

Organization And Summary Of Significant Accounting Policies [Line Items]

Top 50 Songs in the Catalogue

50

Estimated number of songs producing royalty income

1,430

Organization and Summary of Significant Accounting Policies - Additional Information (Detail)			3 Months Ended				6 Months Ended
	Jun. 24, 2026 USD ($) $ / shares	Mar. 26, 2026 USD ($) $ / shares	Jun. 30, 2026 USD ($) $ / shares	Mar. 31, 2026 USD ($) $ / shares	Jun. 30, 2025 USD ($)	Mar. 31, 2010 USD ($)	Jun. 30, 2026 USD ($) $ / shares	Jun. 30, 2025 USD ($)
Organization And Summary Of Significant Accounting Policies [Line Items]
Date of formation of Mills Music Trust			Dec. 03, 1964
Minimum payment of quarterly Contingent Portion						$ 167,500
Distributions to Unit Holders			$ 93,323		$ 0		$ 438,618	$ 0
Top 50 Songs in the Catalogue			EMI has provided the Trust with a listing of the top 50 earning songs in the Catalogue during the 2025 calendar year (the “Top 50 Songs”), together with certain copyright information with respect to each of the Top 50 Songs (the “Listing”). A copy of the Listing, as provided by EMI, is included in the Trust’s annual report on Form 10-K for the fiscal year ended December 31, 2025. The Listing does not include any information regarding Copyrighted Songs for the 2026 calendar year.
Disbursements - Administrative Expenses				$ 78,865			$ 132,540
Distribution to Unit Holders per trust unit \| $ / shares				$ 1.527
Receipts from EMI				$ 424,160
Q4 Contingent Portion Payment [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Distribution to Unit Holders per trust unit \| $ / shares			$ 0.8133	$ 0.8701
Receipts from EMI			$ 225,863	$ 241,647
Q3 Tru Up Payment [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Distribution to Unit Holders per trust unit \| $ / shares				$ 0.3333
Receipts from EMI				$ 92,550
Additional Q4 Amount [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Distribution to Unit Holders per trust unit \| $ / shares				$ 0.3239			$ 0.3239
Receipts from EMI				$ 89,963
Unit Holders [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Distributions to Unit Holders	$ 93,323	$ 345,295
Distribution to Unit Holders per trust unit \| $ / shares	$ 0.336	$ 1.2434
Minimum [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Percentage of Contingent Portion of gross royalty income						65.00%
Maximum [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Percentage of Contingent Portion of gross royalty income						75.00%
Top 50 Song Listing [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Top 50 Songs in the Catalogue			50
Estimated number of songs in the Catalogue			12,000
Estimated number of songs producing royalty income			1,430