Accumulated Other Comprehensive Income (Loss) - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Equity [Abstract]
Net (loss) income	$ (909)	$ 16	$ (932)	$ 75
Foreign currency translation loss			(18)	(31)
Unrealized loss on derivative instruments	(2)	0	(2)	0
Pension adjustment gain			1	0
Comprehensive (loss) income			(951)	44
Comprehensive (loss) income attributable to Covetrus	(930)	11	(949)	38
Comprehensive (loss) income attributable to redeemable non-controlling interests	(3)	0	(2)	6
Comprehensive (loss) income	$ (933)	$ 11	$ (951)	$ 44