Available-for-Sale Debt Investments and Equity Investments (Maturities of Fixed Income Securities) (Details) - USD ($) $ in Millions	Apr. 27, 2019	Jul. 28, 2018
Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract]
Within 1 year	$ 7,363
After 1 year through 5 years	13,892
After 5 years through 10 years	1,760
After 10 years	11
Mortgage-backed securities with no single maturity	1,465
Amortized Cost	24,491	$ 37,512
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Within 1 year	7,353
After 1 year through 5 years	13,826
After 5 years through 10 years	1,756
After 10 years	12
Mortgage-backed securities with no single maturity	1,440
Total	$ 24,387	$ 37,009

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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