Investments, Investments Portfolio and AFS Continuous Unrealized Loss Position (Details) (USD $) In Millions, unless otherwise specified																							3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Oct. 24, 2014	Apr. 25, 2014	Oct. 24, 2014 Available for Sale Securities	Apr. 25, 2014 Available for Sale Securities	Oct. 24, 2014 Corporate Debt Securities	Apr. 25, 2014 Corporate Debt Securities	Oct. 24, 2014 Auction Rate Securities	Apr. 25, 2014 Auction Rate Securities	Oct. 24, 2014 Mortgage Backed Securities	Apr. 25, 2014 Mortgage Backed Securities	Oct. 24, 2014 US Government and Agency Securities	Apr. 25, 2014 US Government and Agency Securities	Oct. 24, 2014 Foreign Government and Agency Securities	Apr. 25, 2014 Foreign Government and Agency Securities	Oct. 24, 2014 Certificates of Deposit	Apr. 25, 2014 Certificates of Deposit	Oct. 24, 2014 Other Asset-backed Securities	Apr. 25, 2014 Other Asset-backed Securities	Oct. 24, 2014 Debt Funds [Member]	Apr. 25, 2014 Debt Funds [Member]	Oct. 24, 2014 Exchange Traded Funds	Apr. 25, 2014 Exchange Traded Funds	Oct. 24, 2014 Debt Securities	Oct. 25, 2013 Debt Securities	Oct. 24, 2014 Debt Securities	Oct. 25, 2013 Debt Securities	Oct. 24, 2014 Equity Securities	Oct. 25, 2013 Equity Securities	Oct. 24, 2014 Equity Securities	Oct. 25, 2013 Equity Securities	Oct. 24, 2014 Nonrecurring	Apr. 25, 2014 Nonrecurring
Available-for-sale securities:
Available-for-sale securities, cost			$ 41	$ 47	$ 5,596	$ 5,504	$ 109	$ 109	$ 1,257	$ 1,337	$ 2,868	$ 3,138	$ 80	$ 67	$ 46	$ 54	$ 469	$ 540	$ 2,775	$ 2,143
Available-For-Sale Securities, Accumulated Gross Unrealized Gain, Before Tax			18	15	69	55	0	0	13	7	11	7	0	0	0	0	2	2	22	9
Available-For-Sale Securities, Accumulated Gross Unrealized Loss, Before Tax			(13)	(13)	(12)	(17)	(10)	(12)	(6)	(8)	(19)	(29)	0	0	0	0	0	0	(55)	(29)
Available-for-sale securities, fair value			46	49	5,653	5,542	99	97	1,264	1,336	2,860	3,116	80	67	46	54	471	542	2,742	2,123
Trading securities:
Trading securities, cost																					56	54
Trading securities, unrealized gains																					14	13
Trading securities, unrealized losses																					0	0
Trading securities, fair value																					70	67
Aggregate carrying amount of investments in equity and other securities that are accounted for using the cost or equity method	563	666																													563	666
Cost method, equity method, and other investments:
Short-term and long-term investments, cost	13,860	13,659
Short-term and long-term investments, unrealized gains	149	108
Short-term and long-term investments, unrealized losses	(115)	(108)
Short-term and long-term investments, fair value	13,331	12,993
AFS Continuous Unrealized Loss Position
Less than 12 months, fair value	3,389	5,032	17	25	1,305	1,601	0	0	327	682	368	1,500							1,372	1,224
Available-For-Sale Securities, Continuous Unrealized Loss Position, Less Than 12 Months, Accumulated Loss	(64)	(90)	(13)	(13)	(8)	(14)	0	0	(2)	(7)	(1)	(27)							(40)	(29)
More than 12 months, fair value	1,321	221	0	0	97	50	99	97	311	28	681	46							133	0
Available-For-Sale Securities, Continuous Unrealized Loss Position, 12 Months Or Longer, Accumulated Loss	(51)	(18)	0	0	(4)	(3)	(10)	(12)	(4)	(1)	(18)	(2)							(15)	0
AFS Gross Realized Gain (Loss)
Proceeds from sales																							806	2,072	2,636	4,235	7	24	29	56
Gross realized gains																							4	0	16	6	39	15	58	33
Gross realized losses																							(2)	(1)	(5)	(6)	0	0	0	0
Impairment losses recognized																							$ 0	$ 0	$ 0	$ 0	$ (20)	$ 0	$ (20)	$ 0