| Document and Entity Information | Apr. 28, 2020 | Feb. 18, 2020 |
| Cover page. | ||
| Document Type | 8-K | |
| Document Period End Date | Apr. 28, 2020 | |
| Entity Registrant Name | TransUnion | |
| Entity Incorporation, State or Country Code | DE | |
| Entity File Number | 001-37470 | |
| Entity Tax Identification Number | 61-1678417 | |
| Entity Address, Address Line One | 555 West Adams Street, | |
| Entity Address, City or Town | Chicago, | |
| Entity Address, State or Province | IL | |
| Entity Address, Postal Zip Code | 60661 | |
| City Area Code | 312 | |
| Local Phone Number | 985-2000 | |
| Written Communications | false | |
| Soliciting Material | false | |
| Pre-commencement Tender Offer | false | |
| Pre-commencement Issuer Tender Offer | false | |
| Title of 12(b) Security | Common Stock, $0.01 par value | |
| Trading Symbol | TRU | |
| Security Exchange Name | NYSE | |
| Entity Emerging Growth Company | false | |
| Entity Central Index Key | 0001552033 | |
| Amendment Flag | false |
