Employee Stock and Savings Plans Summary of Weighted Average Grant Date Fair Values (Details) - $ / shares	12 Months Ended
Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Weighted average grant date fair value	$ 23.82	$ 24.10	$ 21.52
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award
Weighted average grant date fair value	$ 5.22	$ 5.08	$ 4.81

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration