Quarterly report pursuant to Section 13 or 15(d)

Debt - Debt Issuances - Senior Notes (Details)

v2.4.1.9
Debt - Debt Issuances - Senior Notes (Details) (USD $)
3 Months Ended 9 Months Ended 0 Months Ended 1 Months Ended 3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2015
Mar. 31, 2014
Nov. 19, 2014
Nov. 30, 2014
Dec. 31, 2014
Jun. 30, 2014
Oct. 31, 2014
Debt Instrument [Line Items]                  
Cash dividends declared per share (including a special cash dividend of $16.50 per share declared during the three months ended December 31, 2014) $ 0.5us-gaap_CommonStockDividendsPerShareDeclared $ 0.45us-gaap_CommonStockDividendsPerShareDeclared $ 18us-gaap_CommonStockDividendsPerShareDeclared $ 1.35us-gaap_CommonStockDividendsPerShareDeclared          
Discount on debt $ 3,826,000us-gaap_DebtInstrumentUnamortizedDiscount   $ 3,826,000us-gaap_DebtInstrumentUnamortizedDiscount         $ 2,081,000us-gaap_DebtInstrumentUnamortizedDiscount  
Portion of senior notes | Treasury Lock | Forward Contracts | Derivatives Designated as Hedging Instruments | Senior Notes | Cash Flow Hedging                  
Debt Instrument [Line Items]                  
Notional amount of derivative                 1,000,000,000invest_DerivativeNotionalAmount
/ us-gaap_DebtInstrumentAxis
= klac_PortionofSeniorNotesMember
/ us-gaap_DerivativeByNatureAxis
= us-gaap_ForwardContractsMember
/ us-gaap_DerivativeInstrumentRiskAxis
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/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_CashFlowHedgingMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_DesignatedAsHedgingInstrumentMember
/ us-gaap_UnderlyingAssetClassAxis
= us-gaap_SeniorNotesMember
Special Cash Dividend                  
Debt Instrument [Line Items]                  
Cash dividends declared per share (including a special cash dividend of $16.50 per share declared during the three months ended December 31, 2014)         $ 16.50us-gaap_CommonStockDividendsPerShareDeclared
/ us-gaap_DividendsAxis
= klac_SpecialCashDividendMember
$ 16.50us-gaap_CommonStockDividendsPerShareDeclared
/ us-gaap_DividendsAxis
= klac_SpecialCashDividendMember
$ 16.50us-gaap_CommonStockDividendsPerShareDeclared
/ us-gaap_DividendsAxis
= klac_SpecialCashDividendMember
   
Cash dividends             2,760,000,000us-gaap_DividendsCommonStockCash
/ us-gaap_DividendsAxis
= klac_SpecialCashDividendMember
   
Senior Notes                  
Debt Instrument [Line Items]                  
Principal amount           2,500,000,000.0us-gaap_DebtInstrumentFaceAmount
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
     
Discount on debt           4,000,000us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
     
Debt frequency of payment     semi-annually            
Offer to repurchase senior notes, percent of principal amount     101.00%us-gaap_DebtInstrumentRedemptionPricePercentage
/ us-gaap_LongtermDebtTypeAxis
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Fair value 2,600,000,000us-gaap_DebtInstrumentFairValue
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
  2,600,000,000us-gaap_DebtInstrumentFairValue
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
        893,700,000us-gaap_DebtInstrumentFairValue
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
 
Senior Notes | Standard & Poor's, BBplus Rating                  
Debt Instrument [Line Items]                  
Decrease in credit rating, interest rate increase     0.25%klac_DebtInstrumentDecreaseinCreditRatingInterestRateAdjustment
/ us-gaap_CreditRatingStandardPoorsAxis
= us-gaap_StandardPoorsBBPlusRatingMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
           
Senior Notes | Standard & Poor's, BB Rating                  
Debt Instrument [Line Items]                  
Decrease in credit rating, interest rate increase     0.50%klac_DebtInstrumentDecreaseinCreditRatingInterestRateAdjustment
/ us-gaap_CreditRatingStandardPoorsAxis
= us-gaap_StandardPoorsBBRatingMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
           
Senior Notes | Standard & Poor's, BB- Rating                  
Debt Instrument [Line Items]                  
Decrease in credit rating, interest rate increase     0.75%klac_DebtInstrumentDecreaseinCreditRatingInterestRateAdjustment
/ us-gaap_CreditRatingStandardPoorsAxis
= us-gaap_StandardPoorsBBMinusRatingMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
           
Senior Notes | Standard & Poor's, B Plus or Below                  
Debt Instrument [Line Items]                  
Decrease in credit rating, interest rate increase     1.00%klac_DebtInstrumentDecreaseinCreditRatingInterestRateAdjustment
/ us-gaap_CreditRatingStandardPoorsAxis
= us-gaap_StandardPoorsBPlusRatingMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
           
Senior Notes | Moody's, Ba1 Rating                  
Debt Instrument [Line Items]                  
Decrease in credit rating, interest rate increase     0.25%klac_DebtInstrumentDecreaseinCreditRatingInterestRateAdjustment
/ us-gaap_CreditRatingMoodysAxis
= us-gaap_MoodysBa1RatingMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
           
Senior Notes | Moody's, Ba2 Rating                  
Debt Instrument [Line Items]                  
Decrease in credit rating, interest rate increase     0.50%klac_DebtInstrumentDecreaseinCreditRatingInterestRateAdjustment
/ us-gaap_CreditRatingMoodysAxis
= us-gaap_MoodysBa2RatingMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
           
Senior Notes | Moody's, Ba3 Rating                  
Debt Instrument [Line Items]                  
Decrease in credit rating, interest rate increase     0.75%klac_DebtInstrumentDecreaseinCreditRatingInterestRateAdjustment
/ us-gaap_CreditRatingMoodysAxis
= us-gaap_MoodysBa3RatingMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
           
Senior Notes | Moody's, B1 Rating                  
Debt Instrument [Line Items]                  
Decrease in credit rating, interest rate increase     1.00%klac_DebtInstrumentDecreaseinCreditRatingInterestRateAdjustment
/ us-gaap_CreditRatingMoodysAxis
= us-gaap_MoodysB1RatingMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
           
Senior Notes | 2018 Senior Notes                  
Debt Instrument [Line Items]                  
Principal amount           $ 750,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
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/ us-gaap_LongtermDebtTypeAxis
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