| Document and Entity Information | Sep. 11, 2021 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001552033 |
| Document Type | 8-K |
| Document Period End Date | Sep. 11, 2021 |
| Entity Registrant Name | TRANSUNION |
| Entity Incorporation State 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 |
| Security 12b Title | Common Stock, $0.01 par value |
| Trading Symbol | TRU |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
