Fair Value (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Jan. 28, 2012		Jul. 30, 2011
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets, fair value measurements	$ 239		$ 222
Level 1 [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Assets Measured at Fair Value on a Recurring Basis	7,972		7,213
Level 2 [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Assets Measured at Fair Value on a Recurring Basis	37,059		35,662
Liabilities, Fair Value Disclosure	48		24
Level 2 [Member] | Derivative Assets [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets, fair value measurements	238		220
Level 2 [Member] | Derivative Liabilities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities, Fair Value Disclosure	48		24
Level 3 [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Assets Measured at Fair Value on a Recurring Basis	1		123
Level 3 [Member] | Derivative Assets [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets, fair value measurements	1		2
Total [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Assets Measured at Fair Value on a Recurring Basis	45,032		42,998
Liabilities, Fair Value Disclosure	48		24
Total [Member] | Derivative Assets [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets, fair value measurements	239		222
Total [Member] | Derivative Liabilities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities, Fair Value Disclosure	48		24
Available-For-Sale Investments [Member] | Level 1 [Member] | Publicly Traded Equity Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements	1,360		1,361
Available-For-Sale Investments [Member] | Level 2 [Member] | Non-U.S. Government And Agency Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements	2,890	[1]	3,132	[1]
Available-For-Sale Investments [Member] | Level 2 [Member] | U.S. Government Agency Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements	8,546	[2]	8,776	[2]
Available-For-Sale Investments [Member] | Level 2 [Member] | U.S. Government Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements	21,044		19,139
Available-For-Sale Investments [Member] | Level 2 [Member] | Corporate Debt Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements	4,234		4,394
Available-For-Sale Investments [Member] | Level 2 [Member] | Asset-Backed Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements	107
Available-For-Sale Investments [Member] | Level 3 [Member] | Asset-Backed Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements			121
Available-For-Sale Investments [Member] | Total [Member] | Non-U.S. Government And Agency Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements	2,890	[1]	3,132	[1]
Available-For-Sale Investments [Member] | Total [Member] | U.S. Government Agency Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements	8,546	[2]	8,776	[2]
Available-For-Sale Investments [Member] | Total [Member] | U.S. Government Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements	21,044		19,139
Available-For-Sale Investments [Member] | Total [Member] | Corporate Debt Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements	4,234		4,394
Available-For-Sale Investments [Member] | Total [Member] | Asset-Backed Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements	107		121
Available-For-Sale Investments [Member] | Total [Member] | Publicly Traded Equity Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements	1,360		1,361
Cash Equivalents [Member] | Level 1 [Member] | Money Market Funds [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements	6,612		5,852
Cash Equivalents [Member] | Level 2 [Member] | U.S. Government Agency Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements			1	[2]
Cash Equivalents [Member] | Total [Member] | U.S. Government Agency Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements			1	[2]
Cash Equivalents [Member] | Total [Member] | Money Market Funds [Member]
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value measurements	$ 6,612		$ 5,852

[1] Includes agency and corporate debt securities that are guaranteed by non-U.S. governments.

[2] Includes corporate debt securities that are guaranteed by the FDIC.