Summary of Significant Accounting Policies - Narrative (Details) $ in Millions	12 Months Ended
	Jan. 03, 2021 USD ($) Employee Segment	Dec. 29, 2019 USD ($)	Dec. 30, 2018 USD ($)	Dec. 31, 2017
Concentration of Credit Risk [Line Items]
Number of employees | Employee	134,500
Number of business segments | Segment	3
Accrued Rebates Returns And Promotions	$ 11,513	$ 10,883
Minimum reverse repurchase agreement collateral (as a percent)	102.00%
Sales return reserve (as a percent)	1.00%	1.00%	1.00%
Percentage of profit share payments (less than)	3.00%	3.00%	3.00%
Cost of products sold	$ 28,427	$ 27,556	$ 27,091
Shipping and handling costs as a percent of sales	0.50%	0.50%	0.50%
Advertising expense	$ 2,100	$ 2,200	$ 2,600
Operating Lease, Right-of-Use Asset	1,000	1,000
Present Value of lease liabilities	1,100	1,000
Operating lease costs	300	300	$ 300
Cash paid for operating leases	$ 300	$ 300
U.S. statutory rate	21.00%	21.00%	21.00%	35.00%
TCJA, undistributed foreign earnings percent related to cash and cash equivalents				15.50%
TCJA, undistributed foreign earnings percent related to earnings other than cash and cash equivalents				8.00%
TCJA, provisional liability	$ 7,700
TJCA , provisional liability, non-current	6,900
Repatriation of foreign earnings amount	$ 700
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent	us-gaap:OtherLiabilitiesNoncurrent
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssets	us-gaap:OtherAssets
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent
Minimum | Software Development
Concentration of Credit Risk [Line Items]
Estimated useful lives of the assets	3 years
Maximum | Software Development
Concentration of Credit Risk [Line Items]
Estimated useful lives of the assets	8 years
R&D Expense
Concentration of Credit Risk [Line Items]
Concentration risk (as a percent)	5.00%
Shipping and Handling
Concentration of Credit Risk [Line Items]
Cost of products sold	$ 1,000	$ 1,000	$ 1,100
Pharmaceutical
Concentration of Credit Risk [Line Items]
Accrued Rebates Returns And Promotions	$ 7,200	$ 7,000