Schedule of Sales and Operating Income from Continuing Operations by Operating Segment (Details) $ in Thousands		3 Months Ended									12 Months Ended
		Jan. 03, 2021 USD ($)	[1]	Oct. 04, 2020 USD ($)	Jul. 05, 2020 USD ($)	Apr. 05, 2020 USD ($)	Dec. 29, 2019 USD ($)	Sep. 29, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Jan. 03, 2021 USD ($) segments	Dec. 29, 2019 USD ($)	Dec. 30, 2018 USD ($)
Schedule of Segment Reporting Information, by Segment [Line Items]
Operating income from continuing operations		$ 510,254		$ 248,006	$ 175,639	$ 44,682	$ 138,248	$ 78,660	$ 91,735	$ 53,330	$ 978,581	$ 361,973	$ 323,884
Number of Operating Segments | segments											2
Revenue from Contract with Customer, Excluding Assessed Tax											$ 3,782,745	2,883,673	2,777,996
Interest and other expense (income), net											72,217	124,831	66,201
Income from continuing operations before income taxes		$ 473,091		$ 233,757	$ 164,827	$ 34,689	$ 65,296	$ 63,254	$ 71,827	$ 36,765	906,364	237,142	257,683
Defined Benefit Plan, Recognized Net Gain (Loss) on Mark-to-Market											25,400	31,200
Acceleration of executive compensation												7,700
Asset Impairment Charges											7,937	0	0
Significant environmental matters											5,200
Diagnostics [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Operating income from continuing operations											874,206	189,330	153,196
Revenue from Contract with Customer, Excluding Assessed Tax											2,066,942	1,137,512	1,084,785
Asset Impairment Charges											7,900
Discovery & Analytical Solutions [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Operating income from continuing operations	[2]										183,471	238,331	230,481
Revenue from Contract with Customer, Excluding Assessed Tax											1,715,803	1,746,161	1,693,211
Corporate [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Operating income from continuing operations	[3]										(79,096)	(65,688)	(59,793)
Particular Diagnostics Case [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Legal Fees											1,200	100	200
Particular Discovery & Analytical Solutions Case [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Legal Fees											5,900	2,200	5,300
Product [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax											2,778,725	2,017,042	1,935,493
Product [Member] | Diagnostics [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax											1,783,509	962,180	924,594
Product [Member] | Discovery & Analytical Solutions [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax											995,216	1,054,862	1,010,899
Service [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax											1,004,020	866,631	842,503
Service [Member] | Diagnostics [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax											283,433	175,332	160,191
Service [Member] | Discovery & Analytical Solutions [Member]
Schedule of Segment Reporting Information, by Segment [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax											$ 720,587	$ 691,299	$ 682,312

[1] The fourth quarter of fiscal year 2020 includes a pre-tax loss of $25.4 million as a result of the mark-to-market adjustment on postretirement benefit plans. The fourth quarter of fiscal year 2019 includes a pre-tax loss of $31.2 million as a result of the mark-to-market adjustment on postretirement benefit plans. See Note 1 for a discussion of this accounting policy

[2] Legal costs for significant litigation matters and settlements in the Company's Discovery & Analytical Solutions segment were $5.9 million, $2.2 million and $5.3 million for fiscal years 2020, 2019 and 2018, respectively. Legal costs for significant litigation matters and settlements in the Company's Diagnostics segment were $1.2 million, $0.1 million and $0.2 million for fiscal years 2020, 2019 and 2018, respectively.(2)Asset impairment in the Company's Diagnostics segment was $7.9 million for fiscal year 2020.

[3] Costs for significant environmental matters was $5.2 million for fiscal year 2020. Stock compensation expense from acceleration of executive compensation was $7.7 million for fiscal year 2019.