Income Taxes - Restatement Adjustment (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 29, 2018
Income Tax Contingency [Line Items]
Total assets		$ 3,510	$ 3,309	$ 3,510	$ 3,309		$ 3,361
Deferred taxes		39		39			47
Liabilities		1,991		1,991			2,095
Accumulated deficit		(1,061)		(1,061)			(1,040)
Stockholders' Equity Attributable to Parent		1,416	1,276	1,416	1,276	$ 1,276	1,256	$ 2,248	$ 1,494
Liabilities and Equity		3,510		3,510			$ 3,361
Income tax benefit (expense)		(3)	7	(6)	7
Net income (loss)		(35)	(962)	(14)	(985)
Net income (loss) attributable to Covetrus	[1]	$ (35)	$ (959)	$ (15)	$ (982)
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)
Reclassification, Other
Income Tax Contingency [Line Items]
Non-current deferred income tax assets, net			$ 19		$ 19
Total assets			3,309		3,309
Deferred taxes			45		45
Liabilities			2,023		2,023
Accumulated deficit			(992)		(992)
Stockholders' Equity Attributable to Parent			1,276		1,276
Liabilities and Equity			3,309		3,309
Income tax benefit (expense)			7		7
Net income (loss)			(962)		(985)
Net income (loss) attributable to Covetrus			$ (959)		$ (982)
Basic (in usd per share)			$ (8.56)		$ (9.26)
Diluted (in usd per share)			$ (8.56)		$ (9.26)
Previously Reported | Reclassification, Other
Income Tax Contingency [Line Items]
Non-current deferred income tax assets, net			$ 38		$ 38
Total assets			3,328		3,328
Deferred taxes			11		11
Liabilities			1,989		1,989
Accumulated deficit			(939)		(939)
Stockholders' Equity Attributable to Parent			1,329		1,329
Liabilities and Equity			3,328		3,328
Income tax benefit (expense)			60		60
Net income (loss)			(909)		(932)
Net income (loss) attributable to Covetrus			$ (906)		$ (929)
Basic (in usd per share)			$ (8.09)		$ (8.76)
Diluted (in usd per share)			$ (8.09)		$ (8.76)
Revision | Reclassification, Other
Income Tax Contingency [Line Items]
Non-current deferred income tax assets, net			$ (19)		$ (19)
Total assets			(19)		(19)
Deferred taxes			34		34
Liabilities			34		34
Accumulated deficit			(53)		(53)
Stockholders' Equity Attributable to Parent			(53)		(53)
Liabilities and Equity			(19)		(19)
Income tax benefit (expense)			(53)		(53)
Net income (loss)			(53)		(53)
Net income (loss) attributable to Covetrus			$ (53)		$ (53)
Basic (in usd per share)			$ (0.47)		$ (0.50)
Diluted (in usd per share)			$ (0.47)		$ (0.50)

[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.