v3.10.0.1

Available-for-Sale Debt Investments and Equity Investments (Available-for-Sale Investments With Gross Unrealized Losses) (Details) - USD ($) $ in Millions | Oct. 27, 2018 | Jul. 28, 2018
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Schedule of Investments [Line Items] |  |
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value | $ 14,459 | $ 21,093
UNREALIZED LOSSES LESS THAN 12 MONTHS, Gross Unrealized Losses | (272) | (391)
UNREALIZED LOSSES 12 MONTHS OR GREATER, Fair Value | 13,496 | 9,019
UNREALIZED LOSSES 12 MONTHS OR GREATER, Gross Unrealized Losses | (267) | (156)
TOTAL, Fair Value | 27,955 | 30,112
TOTAL, Gross Unrealized Losses | (539) | (547)
U.S. government securities |  |
Schedule of Investments [Line Items] |  |
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value | 516 | 2,966
UNREALIZED LOSSES LESS THAN 12 MONTHS, Gross Unrealized Losses | (3) | (20)
UNREALIZED LOSSES 12 MONTHS OR GREATER, Fair Value | 5,231 | 4,303
UNREALIZED LOSSES 12 MONTHS OR GREATER, Gross Unrealized Losses | (26) | (23)
TOTAL, Fair Value | 5,747 | 7,269
TOTAL, Gross Unrealized Losses | (29) | (43)
U.S. government agency securities |  |
Schedule of Investments [Line Items] |  |
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value | 4 | 206
UNREALIZED LOSSES LESS THAN 12 MONTHS, Gross Unrealized Losses | 0 | (2)
UNREALIZED LOSSES 12 MONTHS OR GREATER, Fair Value | 427 | 521
UNREALIZED LOSSES 12 MONTHS OR GREATER, Gross Unrealized Losses | (4) | (3)
TOTAL, Fair Value | 431 | 727
TOTAL, Gross Unrealized Losses | (4) | (5)
Non-U.S. government and agency securities |  |
Schedule of Investments [Line Items] |  |
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value | 0 | 105
UNREALIZED LOSSES LESS THAN 12 MONTHS, Gross Unrealized Losses | 0 | (1)
UNREALIZED LOSSES 12 MONTHS OR GREATER, Fair Value | 153 | 103
UNREALIZED LOSSES 12 MONTHS OR GREATER, Gross Unrealized Losses | 0 | 0
TOTAL, Fair Value | 153 | 208
TOTAL, Gross Unrealized Losses | 0 | (1)
Corporate debt securities |  |
Schedule of Investments [Line Items] |  |
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value | 13,483 | 16,990
UNREALIZED LOSSES LESS THAN 12 MONTHS, Gross Unrealized Losses | (257) | (344)
UNREALIZED LOSSES 12 MONTHS OR GREATER, Fair Value | 6,738 | 3,511
UNREALIZED LOSSES 12 MONTHS OR GREATER, Gross Unrealized Losses | (189) | (101)
TOTAL, Fair Value | 20,221 | 20,501
TOTAL, Gross Unrealized Losses | (446) | (445)
U.S. agency mortgage-backed securities |  |
Schedule of Investments [Line Items] |  |
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value | 456 | 826
UNREALIZED LOSSES LESS THAN 12 MONTHS, Gross Unrealized Losses | (12) | (24)
UNREALIZED LOSSES 12 MONTHS OR GREATER, Fair Value | 947 | 581
UNREALIZED LOSSES 12 MONTHS OR GREATER, Gross Unrealized Losses | (48) | (29)
TOTAL, Fair Value | 1,403 | 1,407
TOTAL, Gross Unrealized Losses | $ (60) | $ (53)

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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 + Details
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- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 + Details
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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 + Details
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