Cash, Cash Equivalents, Short-Term Investments, Restricted Cash and Investments and Other Assets Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 28, 2014	Jun. 29, 2014
Financial Instruments [Line Items]
Cost	$ 3,065,157lrcx_InvestmentsAmortizedCost	$ 3,228,743lrcx_InvestmentsAmortizedCost
Unrealized Gain	5,898lrcx_InvestmentsUnrealizedGain	6,551lrcx_InvestmentsUnrealizedGain
Unrealized (Loss)	(4,709)lrcx_InvestmentsUnrealizedLoss	(1,400)lrcx_InvestmentsUnrealizedLoss
Fair Value	3,066,346us-gaap_InvestmentsFairValueDisclosure	3,233,894us-gaap_InvestmentsFairValueDisclosure
Cash and Cash Equivalents	981,275	1,452,677
Short-Term Investments	1,902,402	1,612,967
Restricted Cash & Investments	155,455lrcx_RestrictedCashFairValueDisclosure	146,492lrcx_RestrictedCashFairValueDisclosure
Other Assets	27,214us-gaap_OtherAssetsFairValueDisclosure	21,758us-gaap_OtherAssetsFairValueDisclosure
Fair Value Level 1
Financial Instruments [Line Items]
Cost	1,122,400	1,532,030
Unrealized Gain	4,640	3,152
Unrealized (Loss)	(361)	(27)
Fair Value	1,126,679	1,535,155
Cash and Cash Equivalents	673,623	1,168,261
Short-Term Investments	276,142	204,549
Restricted Cash & Investments	149,700	140,587
Other Assets	27,214	21,758
Fair Value Level 2
Financial Instruments [Line Items]
Cost	1,629,350	1,411,682
Unrealized Gain	1,258	3,399
Unrealized (Loss)	(4,348)	(1,373)
Fair Value	1,626,260	1,413,708
Cash and Cash Equivalents		5,290
Short-Term Investments	1,626,260	1,408,418
Fair Value Level 2 \| Municipal Notes And Bonds
Financial Instruments [Line Items]
Cost	250,218	334,329
Unrealized Gain	520	1,108
Unrealized (Loss)	(54)	(4)
Fair Value	250,684	335,433
Cash and Cash Equivalents		5,290
Short-Term Investments	250,684	330,143
Fair Value Level 2 \| Corporate Notes And Bonds
Financial Instruments [Line Items]
Cost	1,127,008	874,540
Unrealized Gain	611	2,034
Unrealized (Loss)	(3,236)	(335)
Fair Value	1,124,383	876,239
Short-Term Investments	1,124,383	876,239
Cash
Financial Instruments [Line Items]
Cost	313,407	285,031
Fair Value	313,407	285,031
Cash and Cash Equivalents	307,652	279,126
Restricted Cash & Investments	5,755	5,905
Time Deposits \| Fair Value Level 1
Financial Instruments [Line Items]
Cost	132,549	132,549
Fair Value	132,549	132,549
Restricted Cash & Investments	132,549	132,549
Money Market Funds \| Fair Value Level 1
Financial Instruments [Line Items]
Cost	673,623	1,168,261
Fair Value	673,623	1,168,261
Cash and Cash Equivalents	673,623	1,168,261
US Treasury and Agencies \| Fair Value Level 1
Financial Instruments [Line Items]
Cost	293,606	212,436
Unrealized Gain	48	178
Unrealized (Loss)	(361)	(27)
Fair Value	293,293	212,587
Short-Term Investments	276,142	204,549
Restricted Cash & Investments	17,151	8,038
Mutual Funds \| Fair Value Level 1
Financial Instruments [Line Items]
Cost	22,622	18,784
Unrealized Gain	4,592	2,974
Fair Value	27,214	21,758
Other Assets	27,214	21,758
Government-Sponsored Enterprises \| Fair Value Level 2
Financial Instruments [Line Items]
Cost	58,450	27,666
Unrealized Gain	11	41
Unrealized (Loss)	(84)	(15)
Fair Value	58,377	27,692
Short-Term Investments	58,377	27,692
Foreign Government Bonds \| Fair Value Level 2
Financial Instruments [Line Items]
Cost	45,022	35,438
Unrealized Gain	6	57
Unrealized (Loss)	(154)	(28)
Fair Value	44,874	35,467
Short-Term Investments	44,874	35,467
Mortgage Backed Securities - Residential \| Fair Value Level 2
Financial Instruments [Line Items]
Cost	17,365	27,067
Unrealized Gain	65	59
Unrealized (Loss)	(103)	(182)
Fair Value	17,327	26,944
Short-Term Investments	17,327	26,944
Mortgage Backed Securities - Commercial \| Fair Value Level 2
Financial Instruments [Line Items]
Cost	131,287	112,642
Unrealized Gain	45	100
Unrealized (Loss)	(717)	(809)
Fair Value	130,615	111,933
Short-Term Investments	$ 130,615	$ 111,933

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This item represents the cost of debt and equity securities, net of adjustments made for accretion, amortization, other-than-temporary impairments, and hedging, if any.

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

+ References

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

+ References

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- Definition

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.

+ References

No definition available.

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- Definition

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.

+ References

No definition available.

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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.

+ References

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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- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: 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 2: 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 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=28360136&loc=d3e22054-111558

Reference 4: 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

Reference 5: 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

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Fair value portion of other assets.

+ References

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