| Cover | Nov. 12, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Nov. 12, 2020 |
| Entity File Number | 001-35498 |
| Entity Registrant Name | Splunk Inc. |
| Entity Central Index Key | 0001353283 |
| Entity Tax Identification Number | 86-1106510 |
| Entity Incorporation, State or Country Code | DE |
| 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 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.001 per share |
| Trading Symbol | SPLK |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
