Segment Data - Operating Results by Segment (Details) - USD ($) $ 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
Segment Reporting Information [Line Items]
Net sales	$ 1,008	$ 1,018	$ 1,009	$ 941	$ 903	$ 923	$ 1,005	$ 947	$ 3,976		$ 3,778	$ 3,580
Adjusted EBITDA									202		220	177
Depreciation and amortization									155		64	59
Income tax benefit (expense)		7							7		(37)	(48)
Total assets	3,361	3,309			2,233				3,361		2,233	2,217
Expenditures for long-lived assets									39		22	21
Net (loss) income attributable to Covetrus	(37)	(959)	(10)	(13)	33	$ 16	$ 29	$ 23	(1,019)	[1]	101	64
Plus: Depreciation and amortization									155		64	59
Plus: Interest expense, net									53		2	2
Earnings before interest, taxes, depreciation, and amortization									(818)		204	173
Plus: Share-based compensation									46		7	7
Plus: Share-based compensation									40		6	4
Plus: Transaction costs									2
Plus: Separation programs and executive severance									11		9
Plus: Formation of Covetrus									34
Plus: Carve-out operating expenses									5
Plus: IT infrastructure									6
Plus: Goodwill impairment	(1)	$ 939	$ 0	$ 0					938		0	0
Less: Minority interest in goodwill impairment									(3)
Less: Other (income) expense items, net									(19)
Adjusted EBITDA									202		220	177
North America
Segment Reporting Information [Line Items]
Net sales									2,111		1,939	1,876
Plus: Goodwill impairment									653
Europe
Segment Reporting Information [Line Items]
Net sales									1,509		1,463	1,373
Plus: Goodwill impairment									221
APAC & Emerging Markets
Segment Reporting Information [Line Items]
Net sales									368		387	349
Plus: Goodwill impairment									64
Operating Segments | North America
Segment Reporting Information [Line Items]
Net sales									2,111		1,939	1,876
Adjusted EBITDA									154		157	136
Depreciation and amortization									131		41	38
Income tax benefit (expense)									8		(18)	(34)
Total assets	2,941				1,343				2,941		1,343	1,301
Expenditures for long-lived assets									23		14	13
Adjusted EBITDA									154		157	136
Operating Segments | Europe
Segment Reporting Information [Line Items]
Net sales									1,509		1,463	1,373
Adjusted EBITDA									68		75	62
Depreciation and amortization									18		17	16
Income tax benefit (expense)									(3)		(15)	(11)
Total assets	726				702				726		702	735
Expenditures for long-lived assets									10		7	7
Adjusted EBITDA									68		75	62
Operating Segments | APAC & Emerging Markets
Segment Reporting Information [Line Items]
Net sales									368		387	349
Adjusted EBITDA									19		20	16
Depreciation and amortization									6		6	5
Income tax benefit (expense)									(4)		(3)	(2)
Total assets	137				182				137		182	174
Expenditures for long-lived assets									1		1	1
Adjusted EBITDA									19		20	16
Corporate
Segment Reporting Information [Line Items]
Net sales									0		0	0
Adjusted EBITDA									(39)		(32)	(37)
Depreciation and amortization									0		0	0
Income tax benefit (expense)									6		(1)	(1)
Total assets	783				10				783		10	11
Expenditures for long-lived assets									5		0	0
Adjusted EBITDA									(39)		(32)	(37)
Eliminations
Segment Reporting Information [Line Items]
Net sales									(12)		(11)	(18)
Adjusted EBITDA									0		0	0
Depreciation and amortization									0		0	0
Income tax benefit (expense)									0		0	0
Total assets	$ (1,226)				$ (4)				(1,226)		(4)	(4)
Expenditures for long-lived assets									0		0	0
Adjusted EBITDA									$ 0		$ 0	$ 0

[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