Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) (USD $) In Millions	12 Months Ended
Jan. 29, 2011	Jan. 30, 2010	Jan. 31, 2009
Consolidated Statements of Changes in Shareholders' Equity
Unrealized loss on investments, tax	$ 1	$ 6	$ 29

Tax effect on gross appreciation or the gross loss in value of the total of unsold securities during the period being reported on.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph c(3)

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
-Paragraph 25

Name:	us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration