Quarterly report pursuant to Section 13 or 15(d)

Investment Income, Net (Details)

v2.4.1.9
Investment Income, Net (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Dec. 28, 2014
Dec. 29, 2013
Investment Income, Net [Abstract]    
Interest and dividend income $ 134us-gaap_InvestmentIncomeInterestAndDividend $ 156us-gaap_InvestmentIncomeInterestAndDividend
Interest expense (1)us-gaap_InterestExpense (3)us-gaap_InterestExpense
Net realized gains on marketable securities 156us-gaap_MarketableSecuritiesRealizedGainLossExcludingOtherThanTemporaryImpairments 128us-gaap_MarketableSecuritiesRealizedGainLossExcludingOtherThanTemporaryImpairments
Net realized gains on other investments 10us-gaap_GainLossOnSaleOfOtherInvestments 17us-gaap_GainLossOnSaleOfOtherInvestments
Impairment losses on marketable securities (62)us-gaap_MarketableSecuritiesRealizedGainLossOtherThanTemporaryImpairmentsAmount (30)us-gaap_MarketableSecuritiesRealizedGainLossOtherThanTemporaryImpairmentsAmount
Impairment losses on other investments (3)qcom_ImpairmentLossesOnOtherInvestments (7)qcom_ImpairmentLossesOnOtherInvestments
Net gains on derivative instruments 4us-gaap_DerivativeGainLossOnDerivativeNet 4us-gaap_DerivativeGainLossOnDerivativeNet
Equity in net losses of investees (4)us-gaap_IncomeLossFromEquityMethodInvestments (1)us-gaap_IncomeLossFromEquityMethodInvestments
Investment income, net $ 234us-gaap_InvestmentIncomeNonoperating $ 264us-gaap_InvestmentIncomeNonoperating