| Document and Entity Information | Sep. 23, 2019 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001703056 |
| Document Type | 8-K |
| Document Period End Date | Sep. 23, 2019 |
| Entity Registrant Name | ADT Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-38352 |
| Entity Tax Identification Number | 47-4116383 |
| Entity Address, Address Line One | 1501 Yamato Road |
| Entity Address, City or Town | Boca Raton |
| Entity Address, State or Province | FL |
| Entity Address, Postal Zip Code | 33431 |
| City Area Code | (561) |
| Local Phone Number | 988-3600 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $0.01 per share |
| Trading Symbol | ADT |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
