BASIS OF PRESENTATION (Policies)	3 Months Ended
BASIS OF PRESENTATION (Policies)	Sep. 28, 2025
Accounting Policies [Abstract]
Consolidation	The condensed consolidated financial statements include the accounts of Lam Research and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Fiscal Period	The Company’s reporting period is a 52/53-week fiscal year. The Company’s current fiscal year will end June 28, 2026 and includes 52 weeks.
Recently Adopted or Effective and Updates Not Yet Effective	Recently Adopted or Effective The Company has not adopted any new accounting standards during the three months ended September 28, 2025 that have a material impact on the Company’s Condensed Consolidated Financial Statements. Updates Not Yet Effective In December 2023, the FASB issued ASU 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures,” which requires public entities to disclose consistent categories and greater disaggregation of information in the rate reconciliation and for income taxes paid. It also includes certain other amendments to improve the effectiveness of income tax disclosures. The guidance is effective for financial statements issued for annual periods beginning after December 15, 2024, with early adoption permitted. The Company is required to adopt this standard prospectively in fiscal year 2026 for the annual reporting period ending June 28, 2026. The Company does not expect the adoption of ASU 2023-09 to have an impact on its Consolidated Financial Statements other than additional footnote disclosures. In November 2024, the FASB issued ASU 2024-03, “Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses,” which requires disaggregation of certain expenses in the notes to the financial statements to provide enhanced transparency into the expense captions presented on the face of the income statement. In January 2025, the FASB issued ASU 2025-01 which clarified the effective date for entities that do not have an annual reporting period that ends on December 31st. The guidance is effective for annual periods beginning after December 15, 2026, and interim reporting periods within annual reporting periods beginning after December 15, 2027, with early adoption permitted. The Company is required to adopt this standard in fiscal year 2028 for the annual reporting period ending June 25, 2028 either (1) prospectively to financial statements issued for reporting periods after the effective date or (2) retrospectively to any or all prior periods presented in the financial statements. The Company will apply the guidance prospectively and is currently in the process of evaluating the impact of adoption on its Consolidated Financial Statements.
Inventories	Inventories are stated at the lower of cost or net realizable value using standard costs that approximate actual costs on a first-in, first-out basis.
Warranties	The Company provides standard warranties on its systems. The liability amount is based on actual historical warranty spending activity by type of system, customer, and geographic region, modified for any known differences such as the impact of system reliability improvements.

Disclosure of inventory accounting policy for inventory classes, including, but not limited to, basis for determining inventory amounts, methods by which amounts are added and removed from inventory classes, loss recognition on impairment of inventories, and situations in which inventories are stated above cost.