Income Taxes - Schedule of Corrections (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019		Dec. 29, 2018	Dec. 30, 2017
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total shareholders’ equity	$ 1,537				$ 1,253				$ 1,537	$ 1,253		$ 1,452	$ 1,215
Total assets	3,496				3,359				3,496	3,359		2,192
Deferred income taxes	28				48				28	48
Total liabilities	1,923				2,096				1,923	2,096
Additional paid-in capital	2,629				2,339				2,629	2,339
Accumulated deficit	(1,027)				(1,001)				(1,027)	(1,001)
Total liabilities, redeemable non-controlling interests, and shareholders’ equity	3,496				3,359				3,496	3,359
Income tax benefit (expense)									7	46		(37)
Net income (loss)									(17)	(983)		107
Net income (loss) attributable to Covetrus	$ (4)	$ (35)	$ 54	$ (33)	$ (37)	$ (920)	$ (10)	$ (13)	$ (19)	$ (980)	[1]	$ 101
Basic (in usd per share)	$ (0.04)	$ (0.33)	$ 0.40	$ (0.30)	$ (0.33)	$ (8.22)	$ (0.09)	$ (0.14)	$ (0.22)	$ (9.14)		$ 1.41
Diluted (in usd per share)	$ (0.04)	$ (0.33)	$ 0.40	$ (0.30)	$ (0.33)	$ (8.22)	$ (0.09)	$ (0.14)	$ (0.22)	$ (9.14)		$ 1.40
Investments and Other
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Non-current deferred income tax assets, net					$ 18					$ 18
Net Former Parent Investment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total shareholders’ equity	$ 0				0				$ 0	0		$ 1,534	1,257
Net income (loss) attributable to Covetrus									$ 0	21	[1]	101
Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total shareholders’ equity					1,256					1,256		1,494
Total assets					3,361					3,361
Deferred income taxes					47					47
Total liabilities					2,095					2,095
Additional paid-in capital					2,381					2,381
Accumulated deficit					(1,040)					(1,040)
Total liabilities, redeemable non-controlling interests, and shareholders’ equity					3,361					3,361
Income tax benefit (expense)										7
Net income (loss)										(1,022)
Net income (loss) attributable to Covetrus										$ (1,019)
Basic (in usd per share)										$ (9.50)
Diluted (in usd per share)										$ (9.50)
Previously Reported | Investments and Other
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Non-current deferred income tax assets, net					20					$ 20
Previously Reported | Net Former Parent Investment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total shareholders’ equity												1,576
Revision
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total shareholders’ equity					(3)					(3)		(42)
Total assets					(2)					(2)
Deferred income taxes					1					1
Total liabilities					1					1
Additional paid-in capital					(42)					(42)
Accumulated deficit					39					39
Total liabilities, redeemable non-controlling interests, and shareholders’ equity					(2)					(2)
Income tax benefit (expense)										39
Net income (loss)										39
Net income (loss) attributable to Covetrus										$ 39
Basic (in usd per share)										$ 0.36
Diluted (in usd per share)										$ 0.36
Revision | Investments and Other
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Non-current deferred income tax assets, net					$ (2)					$ (2)
Revision | Net Former Parent Investment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total shareholders’ equity												$ (42)	$ 42

[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