Investments (Available-For-Sale Investments With Gross Unrealized Losses) (Details) (USD $) In Millions, unless otherwise specified	Apr. 25, 2015	Jul. 26, 2014
Schedule of Investments [Line Items]
Fair value of investment securities with unrealized losses less than 12 months	$ 8,427	$ 10,044
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(17)	(26)
Fair value of investment securities with unrealized losses12 months or greater	158	558
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1)	(4)
Fair value of investment securities with unrealized losses	8,585	10,602
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(18)	(30)
Publicly traded equity securities
Schedule of Investments [Line Items]
Fair value of investment securities with unrealized losses less than 12 months	42	132
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(3)	(10)
Fair value of investment securities with unrealized losses12 months or greater	1	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Fair value of investment securities with unrealized losses	43	132
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(3)	(10)
Total fixed income securities
Schedule of Investments [Line Items]
Fair value of investment securities with unrealized losses less than 12 months	8,385	9,912
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(14)	(16)
Fair value of investment securities with unrealized losses12 months or greater	157	558
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1)	(4)
Fair value of investment securities with unrealized losses	8,542	10,470
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(15)	(20)
Total fixed income securities \| U.S. government securities
Schedule of Investments [Line Items]
Fair value of investment securities with unrealized losses less than 12 months	4,096	7,676
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1)	(12)
Fair value of investment securities with unrealized losses12 months or greater	0	45
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Fair value of investment securities with unrealized losses	4,096	7,721
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(1)	(12)
Total fixed income securities \| U.S. government agency securities
Schedule of Investments [Line Items]
Fair value of investment securities with unrealized losses less than 12 months	702
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1)
Fair value of investment securities with unrealized losses12 months or greater	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0
Fair value of investment securities with unrealized losses	702
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(1)
Total fixed income securities \| Non-U.S. government and agency securities
Schedule of Investments [Line Items]
Fair value of investment securities with unrealized losses less than 12 months		361
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(1)
Fair value of investment securities with unrealized losses12 months or greater		22
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Fair value of investment securities with unrealized losses		383
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		(1)
Total fixed income securities \| Corporate debt securities
Schedule of Investments [Line Items]
Fair value of investment securities with unrealized losses less than 12 months	3,587	1,875
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(12)	(3)
Fair value of investment securities with unrealized losses12 months or greater	157	491
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1)	(4)
Fair value of investment securities with unrealized losses	3,744	2,366
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (13)	$ (7)

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

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This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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