Fair Value of Cash Equivalents and Marketable Securities (Details) (USD $)	Oct. 30, 2011		Jan. 30, 2011
Financial assets and liabilities measured at fair value:
Available-for-sale Securities, Fair Value Disclosure	$ 2,330,585,000		$ 2,175,989,000
Cash equivalents of debt securities issued by US Governement agencies	23,500,000
Marketable securities of debt securities issued by US Government agencies	585,100,000
Cash equivalents of debt securities issued by United States Treasury	23,700,000
Marketable securities of debt securities issued by United States Treasury	408,100,000
Cash equivalents of corporate debt securities	65,600,000
Marketable securities of corporate debt securities	1,042,200,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Financial assets and liabilities measured at fair value:
Available-for-sale Securities, Fair Value Disclosure	146,163,000	[1]	145,422,000
Money Market Funds [Member]
Financial assets and liabilities measured at fair value:
Available-for-sale Securities, Fair Value Disclosure	36,296,000	[2]	132,586,000
US Government Agencies Debt Securities [Member]
Financial assets and liabilities measured at fair value:
Available-for-sale Securities, Fair Value Disclosure	608,632,000	[3]	532,597,000
US Treasury Securities [Member]
Financial assets and liabilities measured at fair value:
Available-for-sale Securities, Fair Value Disclosure	431,747,000	[4]	437,012,000
Corporate Debt Securities [Member]
Financial assets and liabilities measured at fair value:
Available-for-sale Securities, Fair Value Disclosure	1,107,747,000	[5]	928,372,000
Estimate of Fair Value
Financial assets and liabilities measured at fair value:
Total cash equivalents and marketable securities	2,330,585,000
Quoted Price in Active Markets for Identical Assets (Level 1)
Financial assets and liabilities measured at fair value:
Debt securities issued by US Government agencies	0	[3]
Debt securities issued by United States Treasury	0	[4]
Corporate debt securities	0	[5]
Mortgage-backed securitieis issued by Government-sponsored entities	0	[1]
Money market funds	36,296,000	[2]
Total cash equivalents and marketable securities	36,296,000
Significant Other Observable Inputs (Level 2)
Financial assets and liabilities measured at fair value:
Debt securities issued by US Government agencies	608,632,000	[3]
Debt securities issued by United States Treasury	431,747,000	[4]
Corporate debt securities	1,107,747,000	[5]
Mortgage-backed securitieis issued by Government-sponsored entities	146,163,000	[1]
Money market funds	0	[2]
Total cash equivalents and marketable securities	$ 2,294,289,000

[1] Included in Marketable Securities on the Condensed Consolidated Balance Sheet

[2] Included in Cash Equivalents on the Condensed Consolidated Balance Sheet.

[3] Includes $23.5 million in Cash Equivalents and $585.1 million in Marketable Securities on the Condensed Consolidated Balance Sheet.

[4] Includes $23.7 million in Cash Equivalents and $408.1 million in Marketable Securities on the Condensed Consolidated Balance Sheet.

[5] Includes $65.6 million in Cash Equivalents and $1,042.2 million in Marketable Securities on the Condensed Consolidated Balance Sheet.