Earnings Per Share - Reconciliation of Basic Shares to Diluted Shares (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended	3 Months Ended			9 Months Ended
	Feb. 06, 2019	Sep. 30, 2019		Sep. 30, 2018	Sep. 30, 2019		Sep. 30, 2018
Earnings Per Share [Abstract]
Net (loss) income attributable to Covetrus		$ (906)	[1]	$ 16	$ (929)	[1]	$ 67
Basic shares (in shares)		112		71	106		71
Effect of dilutive shares (in shares)	1	0		1	0		1
Diluted shares (in shares)		112		72	106		72
Basic (in usd per share)		$ (8.09)		$ 0.22	$ (8.76)		$ 0.94
Diluted (in usd per share)		$ (8.09)		$ 0.22	$ (8.76)		$ 0.94

[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 (b) See discussion in Note 3 - Business Acquisitions