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This item represents the unrealized gain on debt or equity securities.

No definition available.

Name:	lrcx_InvestmentsUnrealizedGain
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Data Type:	xbrli:monetaryItemType
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This item represents the unrealized loss on debt or equity securities.

No definition available.

Name:	lrcx_InvestmentsUnrealizedLoss
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Data Type:	xbrli:monetaryItemType
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The fair value of cash and investments that is restricted as to withdrawal or usage, valued by the entity on a recurring basis. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits classified as long-term; that is not expected to be released from such existing restrictions within one year of the balance sheet date or operating cycle, whichever is longer. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet.

No definition available.

Name:	lrcx_RestrictedCashFairValueDisclosure
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This element represents investments classified as available for sale reported on the balance sheet at period end measured at fair value on a recurring basis by the entity.

No definition available.

Name:	lrcx_ShortTermInvestmentsFairValueDisclosure
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Data Type:	xbrli:monetaryItemType
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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash Equivalents
-URI http://asc.fasb.org/extlink&oid=6507016

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Data Type:	xbrli:monetaryItemType
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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.

No definition available.

Name:	us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems
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Data Type:	xbrli:stringItemType
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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Trading Securities
-URI http://asc.fasb.org/extlink&oid=6526789

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 35
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=27723805&loc=d3e24584-111560

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=51813488&loc=d3e22054-111558

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Available-for-Sale Securities
-URI http://asc.fasb.org/extlink&oid=6505594

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 1
-Subparagraph a, f, g
-Article 7

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Fair value portion of other assets.

No definition available.

Name:	us-gaap_OtherAssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Name:	us-gaap_InvestmentTypeAxis=us-gaap_CashMember
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Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
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Name:	us-gaap_InvestmentTypeAxis=us-gaap_BankTimeDepositsMember
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Data Type:	na
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Name:	us-gaap_InvestmentTypeAxis=us-gaap_MoneyMarketFundsMember
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Name:	us-gaap_InvestmentTypeAxis=us-gaap_USTreasuryAndGovernmentMember
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Name:	us-gaap_InvestmentTypeAxis=lrcx_MutualFundsMember
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Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
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Name:	us-gaap_InvestmentTypeAxis=us-gaap_MunicipalNotesMember
Namespace Prefix:
Data Type:	na
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Name:	us-gaap_InvestmentTypeAxis=us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
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Name:	us-gaap_InvestmentTypeAxis=us-gaap_ForeignGovernmentDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
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Name:	us-gaap_InvestmentTypeAxis=us-gaap_CorporateBondSecuritiesMember
Namespace Prefix:
Data Type:	na
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Name:	us-gaap_InvestmentTypeAxis=us-gaap_ResidentialMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
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