| Business Combinations  - Fiscal 2019 Acquisitions Additional Information (Details) - Orbotech - USD ($) | 3 Months Ended | ||||||
|---|---|---|---|---|---|---|---|
| Feb. 20, 2019 | Sep. 30, 2019 | ||||||
| Business Acquisition | |||||||
| Total purchase consideration | $ 3,255,558,000 | ||||||
| Cash for outstanding Orbotech shares | [1] | 1,901,948,000 | |||||
| Fair value of KLA-Tencor common stock issued for outstanding Orbotech shares | [2] | 1,324,657,000 | |||||
| Adjustment related to valuation of net tangible assets | $ 2,100,000 | ||||||
| Goodwill deductible for income tax purposes | $ 0 | ||||||
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- Definition Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Tangible Assets, Net No definition available. 
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- Definition 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. 
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- Definition The amount of goodwill arising from a business combination that is expected to be deductible for tax purposes. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Details 
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