v3.25.3

Cover - shares	9 Months Ended
Cover - shares	Sep. 30, 2025	Nov. 12, 2025
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Amendment Flag	false
Document Period End Date	Sep. 30, 2025
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	Q3
Entity Information [Line Items]
Entity Registrant Name	ISQ Open Infrastructure Company LLC
Entity Central Index Key	0002059924
Entity File Number	000-56735
Entity Tax Identification Number	33-2876284
Entity Incorporation, State or Country Code	DE
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Contact Personnel [Line Items]
Entity Address, Address Line One	600 Brickell Avenue
Entity Address, Address Line Two	PH
Entity Address, City or Town	Miami
Entity Address, State or Province	FL
Entity Address, Postal Zip Code	33131
Entity Phone Fax Numbers [Line Items]
City Area Code	(786)
Local Phone Number	693-5739
Entity Listings [Line Items]
Entity Common Stock, Shares Outstanding		3,218,120

Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.

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- Definition

Area code of city

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End date of current fiscal year in the format --MM-DD.

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Fiscal period values are FY, Q1, Q2, and Q3. 1st, 2nd and 3rd quarter 10-Q or 10-QT statements have value Q1, Q2, and Q3 respectively, with 10-K, 10-KT or other fiscal year statements having FY.

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- Definition

This is focus fiscal year of the document report in YYYY format. For a 2006 annual report, which may also provide financial information from prior periods, fiscal 2006 should be given as the fiscal year focus. Example: 2006.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD.

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Boolean flag that is true only for a form used as an quarterly report.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form 10-Q
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-Section 308
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Boolean flag that is true only for a form used as a transition report.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

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No definition available.

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Address Line 1 such as Attn, Building Name, Street Name

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Address Line 2 such as Street or Suite number

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Name of the City or Town

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Code for the postal or zip code

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Name of the state or province.

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- Definition

A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Number 240
-Section 12
-Subsection b-2

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- Definition

Indicate number of shares or other units outstanding of each of registrant's classes of capital or common stock or other ownership interests, if and as stated on cover of related periodic report. Where multiple classes or units exist define each class/interest by adding class of stock items such as Common Class A [Member], Common Class B [Member] or Partnership Interest [Member] onto the Instrument [Domain] of the Entity Listings, Instrument.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Indicate 'Yes' or 'No' whether registrants (1) have filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that registrants were required to file such reports), and (2) have been subject to such filing requirements for the past 90 days. This information should be based on the registrant's current or most recent filing containing the related disclosure.

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- Definition

Indicate if registrant meets the emerging growth company criteria.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Subsection b-2

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- Definition

Indicate if an emerging growth company has elected not to use the extended transition period for complying with any new or revised financial accounting standards.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

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No definition available.

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Indicate whether the registrant is one of the following: Large Accelerated Filer, Accelerated Filer, Non-accelerated Filer. Definitions of these categories are stated in Rule 12b-2 of the Exchange Act. This information should be based on the registrant's current or most recent filing containing the related disclosure.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Two-character EDGAR code representing the state or country of incorporation.

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No definition available.

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Balance Type:	na
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Data Type:	xbrli:stringItemType
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- Definition

Boolean flag that is true when the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Balance Type:	na
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
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-Subsection b-2

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Boolean flag that is true when the registrant is a shell company as defined in Rule 12b-2 of the Exchange Act.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
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-Subsection b-2

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Namespace Prefix:	dei_
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- Definition

Indicates that the company is a Smaller Reporting Company (SRC).

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
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-Section 12
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- Definition

The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
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- Definition

Local phone number for entity.

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No definition available.

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ISQ Open Infrastructure Co LLC 10-Q