| Cover | Nov. 09, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Nov. 09, 2022 |
| Entity File Number | 001-38971 |
| Entity Registrant Name | XL FLEET CORP. |
| Entity Central Index Key | 0001772720 |
| Entity Tax Identification Number | 83-4109918 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 47000 Liberty Drive |
| Entity Address, City or Town | Wixom |
| Entity Address, State or Province | MI |
| Entity Address, Postal Zip Code | 48393 |
| City Area Code | 617 |
| Local Phone Number | 718-0329 |
| 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 $0.0001 per share |
| Trading Symbol | XL |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
