Investments, Investments Portfolio and AFS Continuous Unrealized Loss Position (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended																					3 Months Ended				9 Months Ended				3 Months Ended				9 Months Ended
	Jan. 27, 2012	Jan. 27, 2012	Jan. 25, 2013	Apr. 27, 2012	Jan. 25, 2013 Corporate Debt Securities	Apr. 27, 2012 Corporate Debt Securities	Jan. 25, 2013 Auction Rate Securities	Apr. 27, 2012 Auction Rate Securities	Jan. 25, 2013 Mortgage Backed Securities	Apr. 27, 2012 Mortgage Backed Securities	Jan. 25, 2013 US Government and Agency Securities	Apr. 27, 2012 US Government and Agency Securities	Jan. 25, 2013 Foreign Government and Agency Securities	Apr. 27, 2012 Foreign Government and Agency Securities	Jan. 25, 2013 Certificates of Deposit	Apr. 27, 2012 Certificates of Deposit	Jan. 25, 2013 Other Asset-backed Securities	Apr. 27, 2012 Other Asset-backed Securities	Jan. 25, 2013 Marketable Equity Securities	Apr. 27, 2012 Marketable Equity Securities	Jan. 25, 2013 Exchange Traded Funds	Apr. 27, 2012 Exchange Traded Funds	Jan. 25, 2013 Debt Securities		Jan. 27, 2012 Debt Securities		Jan. 25, 2013 Debt Securities		Jan. 27, 2012 Debt Securities		Jan. 25, 2013 Equity Securities		Jan. 27, 2012 Equity Securities		Jan. 25, 2013 Equity Securities		Jan. 27, 2012 Equity Securities		Jan. 25, 2013 Maximum	Jan. 27, 2012 Salient and PEAK
Available-for-sale securities:
Available-for-sale securities, cost					$ 4,171	$ 3,501	$ 153	$ 153	$ 1,050	$ 840	$ 3,755	$ 3,046	$ 34	$ 67	$ 6	$ 47	$ 504	$ 535	$ 117	$ 100
Available-for-sale securities, unrealized gains					60	47	0	0	8	9	11	38	0	0	0	0	4	3	123	158
Available-for-sale securities, unrealized losses					(7)	(7)	(19)	(26)	(8)	(10)	(3)	0	0	0	0	0	0	(1)	(7)	(5)
Available-for-sale securities, fair value					4,224	3,541	134	127	1,050	839	3,763	3,084	34	67	6	47	508	537	233	253
Trading securities:
Trading securities, cost																					45	45
Trading securities, unrealized gains																					4	2
Trading securities, unrealized losses																					0	(1)
Trading securities, fair value																					49	46
Aggregate carrying amount of investments in equity and other securities that are accounted for using the cost or equity method			486	508
Cost method, equity method, and other investments:
Cost method, equity method, and other investments, fair value			486	508
Short-term and long-term investments, cost			10,321	8,842
Short-term and long-term investments, unrealized gains			210	257
Short-term and long-term investments, unrealized losses			(44)	(50)
Short-term and long-term investments, fair value			10,487	9,049
AFS Continuous Unrealized Loss Position
Less than 12 months, fair value			3,006	961	1,038	664	0	0	459	218	1,459						37	55	13	24
Less than 12 months, unrealized losses			(17)	(11)	(4)	(4)	0	0	(3)	(2)	(3)						0	0	(7)	(5)
More than 12 months, fair value			213	209	23	16	134	127	54	57	0						2	9	0	0
More than 12 months, unrealized losses			(27)	(38)	(3)	(3)	(19)	(26)	(5)	(8)	0						0	(1)	0	0
AFS Gross Realized Gain (Loss)
Proceeds from sales																							1,506	[1]	1,486	[1]	6,306	[1]	4,453	[1]	25	[2]	28	[2]	90	[2]	81	[2],[3]
Gross realized gains																							9	[1]	21	[1]	51	[1]	45	[1]	16	[2]	17	[2]	52	[2]	72	[2],[3]
Gross realized losses																							(5)	[1]	(6)	[1]	(12)	[1]	(13)	[1]	0	[2]	0	[2]	0	[2]	0	[2],[3]
Impairment losses recognized																							0	[1]	(1)	[1]	0	[1]	(2)	[1]	0	[2]	0	[2]	(10)	[2]	(4)	[2],[3]
Gain on previously held investments																																								38
AFS OTTI Losses
Total OTTI losses recognized	2	5
OTTI losses recognized in OCI	1	3
OTTI losses recognized in earnings	$ 1	$ 2

[1] Includes available-for-sale debt securities.

[2] Includes marketable equity securities, cost method, equity method, exchange-traded funds, and other investments.

[3] As a result of the Salient and PEAK acquisitions, the Company recognized a non-cash gain of $38 million during the nine months ended January 27, 2012 on its previously held minority investments.