Disposition (Details) - USD ($) $ in Millions	3 Months Ended								6 Months Ended	12 Months Ended
	Dec. 31, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 31, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 28, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal										$ 482	$ 0	$ 0
Revenues	$ 6,829	$ 6,272	$ 6,316	$ 6,125	$ 6,507	$ 5,920	$ 6,078	$ 5,853		25,542	24,358	$ 20,918
Current Assets	11,893				10,625					11,893	10,625
Current Liabilities	$ 6,197				6,147					6,197	6,147
Anatomical Pathology business [Member] | Disposal Group, Held-for-sale, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Consideration									$ 1,130
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal										$ 478
Revenues									$ 115		238
Current Assets					81						81
Long-term Assets					528						528
Current Liabilities					34						34
Long-term Liabilities					$ 24						$ 24