Earnings (Loss) Per Share - Reconciliation of Basic Shares to Diluted Shares (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income (loss) attributable to Covetrus	[1]	$ (35)	$ (959)	$ (15)	$ (982)
Dividends declared on Series A preferred stock		(4)	0	(6)	0
Income (loss) available to common shareholders		$ (39)	$ (959)	$ (21)	$ (982)
Basic shares (in shares)		116	112	113	106
Effect of dilutive shares (in shares)		0	0	0	0
Diluted shares (in shares)		116	112	113	106
Basic (in usd per share)		$ (0.33)	$ (8.56)	$ (0.18)	$ (9.26)
Diluted (in usd per share)		$ (0.33)	$ (8.56)	$ (0.18)	$ (9.26)
Potential dilutive securities		26	6	27	4
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive Securities Excluded from Computation, Dilutive Securities, Percent of Total		73.00%
Series A Preferred Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive Securities Excluded from Computation, Dilutive Securities, Percent of Total				74.00%

[1] (a) Net income earned from January 1, 2019 through February 7, 2019 is attributed to the Former Parent as it was the sole shareholder prior to February 7, 2019.