Investments (Tables)

9 Months Ended

Apr. 28, 2012

Investments [Abstract]

Summary Of Available-For-Sale Investments

April 28, 2012	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Fixed income securities:
U.S. government securities	$	25,118	$	41	$	(2	)	$	25,157
U.S. government agency securities		6,884		24		—			6,908
Non-U.S. government and agency securities		2,219		8		—			2,227
Corporate debt securities		6,080		57		(6	)		6,131
Asset-backed securities		16		—		(2	)		14
Total fixed income securities		40,317		130		(10	)		40,437
Publicly traded equity securities		826		692		(4	)		1,514
Total	$	41,143	$	822	$	(14	)	$	41,951
July 30, 2011	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Fixed income securities:
U.S. government securities	$	19,087	$	52	$	—		$	19,139
U.S. government agency securities		8,742		35		(1	)		8,776
Non-U.S. government and agency securities		3,119		14		(1	)		3,132
Corporate debt securities		4,333		65		(4	)		4,394
Asset-backed securities		120		5		(4	)		121
Total fixed income securities		35,401		171		(10	)		35,562
Publicly traded equity securities		734		639		(12	)		1,361
Total	$	36,135	$	810	$	(22	)	$	36,923

Gross Realized Gains And Gross Realized Losses Related To Available-For-Sale Investments

	Three Months Ended						Nine Months Ended
	April 28, 2012			April 30, 2011			April 28, 2012			April 30, 2011
Gross realized gains	$	118		$	107		$	542		$	272
Gross realized losses		(88	)		(58	)		(466	)		(116	)
Total	$	30		$	49		$	76		$	156

Gross Realized Gains Net Of Gross Realized Losses Related To Available-For-Sale Investments

	Three Months Ended				Nine Months Ended
	April 28, 2012		April 30, 2011		April 28, 2012		April 30, 2011
Net gains on investments in publicly traded equity securities	$	15	$	42	$	30	$	72
Net gains on investments in fixed income securities		15		7		46		84
Total	$	30	$	49	$	76	$	156

Credit Losses For Fixed Income Securities

Nine Months Ended	April 28, 2012			April 30, 2011
Balance at beginning of period	$	(23	)	$	(95	)
Sales of other-than-temporarily impaired fixed income securities		22			52
Balance at end of period	$	(1	)	$	(43	)

Available-For-Sale Investments With Gross Unrealized Losses

	UNREALIZED LOSSES LESS THAN 12 MONTHS					UNREALIZED LOSSES 12 MONTHS OR GREATER					TOTAL
April 28, 2012	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Fixed income securities:
U.S. government securities	$	6,756	$	(2	)	$	—	$	—		$	6,756	$	(2	)
Corporate debt securities		1,718		(6	)		21		—			1,739		(6	)
Asset-backed securities		—		—			14		(2	)		14		(2	)
Total fixed income securities		8,474		(8	)		35		(2	)		8,509		(10	)
Publicly traded equity securities		42		(4	)		1		—			43		(4	)
Total	$	8,516	$	(12	)	$	36	$	(2	)	$	8,552	$	(14	)
	UNREALIZED LOSSES LESS THAN 12 MONTHS					UNREALIZED LOSSES 12 MONTHS OR GREATER					TOTAL
July 30, 2011	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Fixed income securities:
U.S. government agency securities	$	2,310	$	(1	)	$	—	$	—		$	2,310	$	(1	)
Non-U.S. government and agency securities		875		(1	)		—		—			875		(1	)
Corporate debt securities		548		(2	)		56		(2	)		604		(4	)
Asset-backed securities		—		—			105		(4	)		105		(4	)
Total fixed income securities		3,733		(4	)		161		(6	)		3,894		(10	)
Publicly traded equity securities		112		(12	)		—		—			112		(12	)
Total	$	3,845	$	(16	)	$	161	$	(6	)	$	4,006	$	(22	)

Maturities Of Fixed Income Securities

	Amortized Cost		Fair Value
Less than 1 year	$	18,983	$	19,005
Due in 1 to 2 years		13,046		13,091
Due in 2 to 5 years		8,175		8,226
Due after 5 years		113		115
Total	$	40,317	$	40,437