Cover Page - shares	6 Months Ended
	Jul. 31, 2020	Aug. 28, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jul. 31, 2020
Document Transition Report	false
Entity File Number	001-35498
Entity Registrant Name	Splunk Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	86-1106510
Entity Address, Address Line One	270 Brannan Street
Entity Address, City or Town	San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94107
City Area Code	415
Local Phone Number	848-8400
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	SPLK
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		160,393,964
Entity Central Index Key	0001353283
Amendment Flag	false
Current Fiscal Year End Date	--01-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2