| Document and Entity Information | Oct. 22, 2021 |
| Cover [Abstract] | |
| Entity Registrant Name | APi Group Corp |
| Amendment Flag | false |
| Entity Central Index Key | 0001796209 |
| Document Type | 8-K |
| Document Period End Date | Oct. 22, 2021 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-39275 |
| Entity Tax Identification Number | 98-1510303 |
| Entity Address, Address Line One | 1100 Old Highway 8 NW |
| Entity Address, City or Town | New Brighton |
| Entity Address, State or Province | MN |
| Entity Address, Postal Zip Code | 55112 |
| City Area Code | (651) |
| Local Phone Number | 636-4320 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $0.0001 per share |
| Trading Symbol | APG |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
