Cover - shares	6 Months Ended
	Jun. 30, 2022	Aug. 05, 2022
Cover [Abstract]
Document type	10-Q
Document quarterly report	true
Document period end date	Jun. 30, 2022
Document transition report	false
Entity file number	001-38971
Entity registrant name	XL Fleet Corp.
Entity incorporation, state or country code	DE
Entity tax identification number	83-4109918
Entity address, address line one	145 Newton Street
Entity address, city or town	Boston
Entity address, state or province	MA
Entity address, postal zip code	02135
City area code	(617)
Local phone number	718-0329
Title of 12(b) security	Shares of common stock, $0.0001 par value
Trading symbol	XL
Security exchange name	NYSE
Entity current reporting status	Yes
Entity interactive data current	Yes
Entity filer category	Large Accelerated Filer
Entity small business	false
Entity emerging growth company	false
Entity shell company	false
Entity common stock, shares outstanding		142,496,231
Entity central index key	0001772720
Current fiscal year end date	--12-31
Document fiscal period focus	Q2
Document fiscal year focus	2022
Amendment flag	false