Document and Entity Information - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Mar. 03, 2026 |
Jun. 30, 2025 |
|
| Cover [Abstract] | |||
| Document Type | 10-K | ||
| Amendment Flag | false | ||
| Document Period End Date | Dec. 31, 2025 | ||
| Document Fiscal Year Focus | 2025 | ||
| Document Fiscal Period Focus | FY | ||
| Entity Registrant Name | Phillip Street Middle Market Lending Fund LLC | ||
| Entity Central Index Key | 0001948368 | ||
| Entity Current Reporting Status | Yes | ||
| Entity Interactive Data Current | Yes | ||
| Current Fiscal Year End Date | --12-31 | ||
| Entity Filer Category | Non-accelerated Filer | ||
| Entity Shell Company | false | ||
| Entity Small Business | false | ||
| Entity Emerging Growth Company | true | ||
| Entity File Number | 814-01579 | ||
| Entity Well-known Seasoned Issuer | No | ||
| Entity Voluntary Filers | No | ||
| Entity Incorporation, State or Country Code | DE | ||
| Entity Tax Identification Number | 92-0758632 | ||
| Entity Address, Address Line One | 200 West Street | ||
| Entity Address, City or Town | New York | ||
| Entity Address, State or Province | NY | ||
| Entity Address, Postal Zip Code | 10282 | ||
| City Area Code | 312 | ||
| Local Phone Number | 655-4419 | ||
| Title of 12(g) Security | Limited Liability Company Common Units | ||
| Document Annual Report | true | ||
| Document Transition Report | false | ||
| ICFR Auditor Attestation Flag | false | ||
| Entity Common Stock, Shares Outstanding | 27,234,468 | ||
| Entity Public Float | $ 0 | ||
| Entity Ex Transition Period | true | ||
| Auditor Name | PricewaterhouseCoopers LLP | ||
| Auditor Location | Boston, Massachusetts | ||
| Auditor Firm ID | 238 | ||
| Auditor Opinion [Text Block] | Opinion on the Financial Statements
We have audited the accompanying consolidated statements of financial condition, including the consolidated schedules of investments, of Phillip Street Middle Market Lending Fund LLC and its subsidiaries (the “Company”) as of December 31, 2025 and 2024, and the related consolidated statements of operations, changes in members’ capital and cash flows for each of the three years in the period ended December 31, 2025 including the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2025 and 2024, and the results of its operations, changes in its members’ capital and its cash flows for each of the three years in the period ended December 31, 2025 in conformity with accounting principles generally accepted in the United States of America. |
||
| Document Financial Statement Error Correction [Flag] | false |