Goodwill And Intangible Assets (Narrative) (Details) (USD $) In Millions	6 Months Ended	12 Months Ended
Jul. 31, 2011	Jul. 31, 2010	Jan. 31, 2011	Jan. 31, 2009
Goodwill And Intangible Assets
Recast of goodwill to show effect of discontinued operations in reportable segments			$ 14
Amortization expense related to amortizable intangible assets	22	17
Goodwill or intangible asset impairment losses	0	0
Fully amortized intangible assets, gross carrying value			17
Carrying value of goodwill related to discontinued operations				$ 13

For the disposal group, including a component of the entity (discontinued operation), carrying amount of goodwill (adjusted for any amortization recognized prior to adoption of FAS 142 and impairment charges).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 144
-Paragraph 47
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760

Name:	us-gaap_DisposalGroupIncludingDiscontinuedOperationGoodwill
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant