Business Acquisitions and Divestitures (Narrative) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Business Acquisition [Line Items]
Net sales	$ 2,668,941,000	$ 2,508,767,000	$ 2,447,827,000	$ 2,360,268,000	$ 2,472,556,000	$ 2,355,565,000	$ 2,316,032,000	$ 2,273,450,000	$ 9,985,803,000	$ 9,417,603,000	$ 8,883,438,000
Business acquisition allocated, goodwill	2,462,495,000				2,081,029,000				2,462,495,000	2,081,029,000	1,553,582,000
Net gain (loss) on sale of equity investments	(186,769,000)	$ 0	$ 0	$ 0					(186,769,000)	0	17,636,000
Income Tax Expense (Benefit)									159,515,000	107,432,000	308,975,000
Equity in earnings of affiliates									(17,900,000)	(21,037,000)	(15,293,000)
Business Acquisition, Transaction Costs	4,500,000				7,300,000				4,500,000	7,300,000	5,300,000
Proceeds from sale of equity investment									307,251,000	1,000,000	34,048,000
Hu-Friedy Mfg. Co., LLC [Member]
Business Acquisition [Line Items]
Net gain (loss) on sale of equity investments	(250,200,000)
Income Tax Expense (Benefit)	63,400,000
Equity in earnings of affiliates									(6,000,000.0)	(10,400,000)	(6,400,000)
E4D Technologies [Member]
Business Acquisition [Line Items]
Net gain (loss) on sale of equity investments											17,600,000
Income Tax Expense (Benefit)											0
Animal Health [Member]
Business Acquisition [Line Items]
Business Acquisition, Transaction Costs	23,600,000				38,900,000				23,600,000	38,900,000
Technology and Value-Added Services [Member]
Business Acquisition [Line Items]
Net sales									515,085,000	408,439,000	337,633,000
Business acquisition allocated, goodwill	$ 985,776,000				$ 647,617,000				985,776,000	647,617,000	121,902,000
Income Tax Expense (Benefit)									30,134,000	$ 53,772,000	$ 37,055,000
Internet Brands Inc [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Increase from Business Combination									$ 550,900,000
Internet Brands Inc [Member] | Henry Schein One, LLC. [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	26.00%								26.00%
Noncontrolling interest, ownership percentage increase, second through fifth anniversary									7.60%
Noncontrolling interest, ownership percentage maximum additional increase, contingency									1.60%
Henry Schein One, LLC. [Member] | Technology and Value-Added Services [Member]
Business Acquisition [Line Items]
Business acquisition allocated, goodwill	$ 533,900,000								$ 533,900,000
Henry Schein Inc, and certain minority holders, if applicable [Member] | Henry Schein One, LLC. [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	74.00%								74.00%
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Increase from Business Combination									$ 72,500,000
Net assets	$ 19,700,000								19,700,000
Business acquisition allocated, goodwill	395,300,000								395,300,000
Intangible Assets	$ 310,400,000								310,400,000
Payments to Acquire Businesses									$ 652,900,000