Income Taxes - Schedule of Corrections (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 29, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019		Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Non-current deferred income tax assets, net		$ 19
Total assets	$ 3,361	3,309			$ 2,233				$ 3,361		$ 2,233	$ 2,217
Deferred income taxes	47	45			16				47		16
Total liabilities	2,095	2,023			647				2,095		647
Accumulated deficit	(1,040)	(992)			0				(1,040)		0
Total shareholders’ equity	1,256	1,276			1,494				1,256		1,494	1,257	$ 1,120
Total liabilities, redeemable non-controlling interests, and shareholders’ equity	3,361	3,309			2,233				3,361		2,233
Income tax benefit (expense)		7							7		(37)	(48)
Net (loss) income		(962)							(1,022)		107	92
Net (loss) income attributable to Covetrus	$ (37)	$ (959)	$ (10)	$ (13)	$ 33	$ 16	$ 29	$ 23	$ (1,019)	[1]	$ 101	$ 64
Basic (in usd per share)	$ (0.33)	$ (8.56)	$ (0.09)	$ (0.14)	$ 0.47	$ 0.22	$ 0.40	$ 0.32	$ (9.50)		$ 1.41	$ 0.90
Diluted (in usd per share)	$ (0.33)	$ (8.56)	$ (0.09)	$ (0.14)	$ 0.46	$ 0.22	$ 0.40	$ 0.31	$ (9.50)		$ 1.40	$ 0.89
Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Non-current deferred income tax assets, net		$ 38
Total assets		3,328
Deferred income taxes		11
Total liabilities		1,989
Accumulated deficit		(939)
Total shareholders’ equity		1,329
Total liabilities, redeemable non-controlling interests, and shareholders’ equity		3,328
Income tax benefit (expense)		60
Net (loss) income		(909)
Net (loss) income attributable to Covetrus		$ (906)
Basic (in usd per share)		$ (8.09)
Diluted (in usd per share)		$ (8.09)
Revision
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Non-current deferred income tax assets, net		$ (19)
Total assets		(19)
Deferred income taxes		34
Total liabilities		34
Accumulated deficit		(53)
Total shareholders’ equity		(53)
Total liabilities, redeemable non-controlling interests, and shareholders’ equity		(19)
Income tax benefit (expense)		(53)
Net (loss) income		(53)
Net (loss) income attributable to Covetrus		$ (53)
Basic (in usd per share)		$ (0.47)
Diluted (in usd per share)		$ (0.47)

[1] 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