Deferred Revenue and Performance Obligations - Additional Information (Detail) - Subscription services - USD ($) $ in Millions	3 Months Ended
Apr. 30, 2020	Apr. 30, 2019
Revenue From Contracts With Customers [Line Items]
Recognition of deferred revenue	$ 192	$ 146
Revenue expected to be recognized from remaining performance obligations	$ 913

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130549-203045

Name:	us-gaap_ContractWithCustomerLiabilityRevenueRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration