v3.10.0.1

Available-for-Sale Debt Investments and Equity Investments (Summary of Available-for-Sale Investments) (Details) - USD ($) $ in Millions | Oct. 27, 2018 | Jul. 28, 2018
--- | --- | ---
Schedule of Investments [Line Items] |  |
Amortized Cost | $ 34,689 | $ 37,512
Gross Unrealized Gains | 33 | 44
Gross Unrealized Losses | (539) | (547)
Fair Value | 34,183 | 37,009
Net unsettled, available-for-sale investments purchases (sales), net | 1 | (1,500)
U.S. government securities |  |
Schedule of Investments [Line Items] |  |
Amortized Cost | 5,783 | 7,318
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (29) | (43)
Fair Value | 5,754 | 7,275
U.S. government agency securities |  |
Schedule of Investments [Line Items] |  |
Amortized Cost | 434 | 732
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (4) | (5)
Fair Value | 430 | 727
Non-U.S. government and agency securities |  |
Schedule of Investments [Line Items] |  |
Amortized Cost | 153 | 209
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | 0 | (1)
Fair Value | 153 | 208
Corporate debt securities |  |
Schedule of Investments [Line Items] |  |
Amortized Cost | 26,444 | 27,765
Gross Unrealized Gains | 33 | 44
Gross Unrealized Losses | (446) | (445)
Fair Value | 26,031 | 27,364
U.S. agency mortgage-backed securities |  |
Schedule of Investments [Line Items] |  |
Amortized Cost | 1,481 | 1,488
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (60) | (53)
Fair Value | 1,421 | $ 1,435
Commercial paper |  |
Schedule of Investments [Line Items] |  |
Amortized Cost | 309 |
Gross Unrealized Gains | 0 |
Gross Unrealized Losses | 0 |
Fair Value | 309 |
Certificates of deposit |  |
Schedule of Investments [Line Items] |  |
Amortized Cost | 85 |
Gross Unrealized Gains | 0 |
Gross Unrealized Losses | 0 |
Fair Value | $ 85 |

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- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
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