Deferred Costs (Details) - USD ($)	3 Months Ended	6 Months Ended
Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2021	Jul. 31, 2020	Jan. 31, 2021
Revenue from Contract with Customer [Abstract]
Deferred sales commission	$ 408,000,000		$ 408,000,000		$ 395,000,000
Amortization of deferred costs	33,000,000	$ 27,000,000	65,000,000	$ 53,000,000
Capitalized contract cost, impairment loss	$ 0	$ 0	$ 0	$ 0

Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123353750&loc=SL49131252-203054

Name:	us-gaap_CapitalizedContractCostNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant