Earnings (Loss) Per Share - Reconciliation of Basic Shares to Diluted Shares (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Net loss attributable to Covetrus	[1]	$ (33)	$ (13)
Basic shares (in shares)		112	95
Effect of dilutive shares (in shares)		0	0
Diluted shares (in shares)		112	95
Basic (in usd per share)		$ (0.30)	$ (0.14)
Diluted (in usd per share)		$ (0.30)	$ (0.14)

[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