Accumulated Other Comprehensive Income (Loss) - Schedule of Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 29, 2018	Dec. 30, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Common stock, shares beginning balance	$ 1,494	$ 1,257	$ 1,120
Other comprehensive income (loss) attributable to Covetrus before reclassifications	(5)	(40)	60
Gain reclassified from Accumulated other comprehensive loss to earnings	1
Common stock, shares ending balance	1,256	1,494	1,257
Derivative (Loss) Gain
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Common stock, shares beginning balance	0
Other comprehensive income (loss) attributable to Covetrus before reclassifications	(1)
Gain reclassified from Accumulated other comprehensive loss to earnings	1
Common stock, shares ending balance	0	0
(Loss) Gain on Pension Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Common stock, shares beginning balance	0	(2)	(2)
Other comprehensive income (loss) attributable to Covetrus before reclassifications	0	2	0
Gain reclassified from Accumulated other comprehensive loss to earnings	0
Common stock, shares ending balance	0	0	(2)
Foreign Currency Translation (Loss) Gain
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Common stock, shares beginning balance	(82)	(41)	(100)
Other comprehensive income (loss) attributable to Covetrus before reclassifications	(4)	(41)	59
Gain reclassified from Accumulated other comprehensive loss to earnings	0
Common stock, shares ending balance	(86)	(82)	(41)
Unrealized Gain (Loss) from Foreign Currency Hedging
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Common stock, shares beginning balance	0	1	0
Other comprehensive income (loss) attributable to Covetrus before reclassifications		(1)	1
Common stock, shares ending balance		0	1
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Common stock, shares beginning balance	(82)	(42)	(102)
Common stock, shares ending balance	$ (86)	$ (82)	$ (42)