Business Overview and Significant Accounting Policies (Details) - USD ($) $ in Millions		12 Months Ended
	Feb. 07, 2019	Dec. 31, 2019	Dec. 29, 2018	Dec. 30, 2017	Jan. 01, 2019
Business Acquisition [Line Items]
Valuation allowance for deferred tax assets		$ 49	$ 1
Advertising expense		17	16	$ 15
Cost of sales		3,227	3,094	2,928
Operating lease right-of-use assets, net		84
Operating lease liabilities		86
ASU 2016-02
Business Acquisition [Line Items]
Operating lease right-of-use assets, net					$ 65
Operating lease liabilities					$ 67
Distribution network costs
Business Acquisition [Line Items]
Cost of sales		18	$ 18	$ 16
Share Sale
Business Acquisition [Line Items]
Issuance of common shares in connection with the merger	$ 361
Henry Schein
Business Acquisition [Line Items]
Cash dividend paid to sole shareholder	$ 1,200
Percentage ownership, parent	63.00%
Vets First Choice
Business Acquisition [Line Items]
Percentage ownership, noncontrolling interest	37.00%
Revision | Deferred tax calculation error
Business Acquisition [Line Items]
Valuation allowance for deferred tax assets		$ 53