BASIS OF PRESENTATION (Policies)	9 Months Ended
BASIS OF PRESENTATION (Policies)	Mar. 28, 2021
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 27, 2021 and includes 52 weeks.
Recent Accounting Pronouncements	Recently Adopted In June 2016, the Financial Accounting Standards Board (“FASB”) released Accounting Standards Update (“ASU”) 2016-13, “Financial Instruments – Credit Losses (Topic 326).” The amendment revises the impairment model to utilize an expected loss methodology in place of the previously used incurred loss methodology, which will result in more timely recognition of losses on financial instruments, including but not limited to, available for sale debt securities and accounts receivable. The FASB issued a subsequent amendment to the initial guidance in April 2019 and November 2019 within ASU 2019-04 and ASU 2019-11, respectively. The adoption of these standards in the first quarter of fiscal year 2021 did not have a material impact on the Company’s Condensed Consolidated Financial Statements. In November 2018, the FASB issued ASU 2018-18, “Collaborative Arrangements (Topic 808).” The amendment clarifies that certain transactions between participants in a collaborative arrangement should be accounted for under Topic 606 when the counterparty is a customer for a good or service that is a distinct unit of account. The amendment also precludes entities from presenting consideration from transactions with a collaborator that is not a customer together with revenue recognized from contracts with customers. The adoption of this standard in the first quarter of fiscal year 2021 did not have a material impact on the Company’s Condensed Consolidated Financial Statements. In March 2020, the FASB issued ASU 2020-04, “Reference Rate Reform (Topic 848) - Facilitation of the Effects of Reference Rate Reform on Financial Reporting.” The ASU provides temporary optional expedients and exceptions for applying generally accepted accounting principles to contract modifications and hedging relationships, subject to meeting certain criteria, that reference the London Interbank Offered Rate (“LIBOR”) or another reference rate expected to be discontinued. In January 2021, the FASB issued ASU 2021-01, “ Reference Rate Reform (Topic 848),” which permits entities to apply optional expedients in Topic 848 to derivative instruments modified because of discounting transition resulting from reference rate reform. ASU 2020-04 became effective upon issuance and may be applied prospectively to contract modifications made on or before December 31, 2022. ASU 2021-01 became effective upon issuance and may be applied on a full retrospective basis as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020 or prospectively for contract modifications made on or before December 31, 2022. The Company has not yet applied the relief afforded by these standard amendments and is currently assessing contracts that will require modification due to reference rate reform to which these standard amendments may be applied. Updates Not Yet Adopted or EffectiveIn August 2020, the FASB issued ASU No. 2020-06, “Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity”, which simplifies the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts in an entity’s own equity. Among other changes, ASU 2020-06 removes from U.S. GAAP the liability and equity separation model for convertible instruments with a cash conversion feature, and as a result, after adoption, entities will no longer separately present in equity an embedded conversion feature for such debt. ASU 2020-06 also eliminates the treasury stock method to calculate diluted earnings per share and requires the if-converted method. The provisions of ASU 2020-06 are applicable for fiscal years beginning after December 15, 2021, with early adoption permitted no earlier than fiscal years beginning after December 15, 2020. The Company is required to adopt this standard in the first quarter of fiscal year 2023. The update permits the use of either the modified retrospective or fully retrospective method of transition. The Company does not expect adoption of this standard to have a material impact on its Consolidated Financial Statements related to the Company’s existing 2041 Notes (as defined in Note 12 - Long-Term Debt and Other Borrowings ).
Inventories	Inventories are stated at the lower of cost (first-in, first-out method) or net realizable value. System shipments to customers in Japan, for which title does not transfer until customer acceptance, are classified as finished goods inventory and carried at cost until title transfers.
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.