Summary of significant accounting policies - Narrative (Details) $ / shares in Units, $ in Millions			12 Months Ended
	Aug. 23, 2023	May 08, 2023 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) Segment Employee $ / shares	Jan. 01, 2023 USD ($) $ / shares	Jan. 02, 2022 USD ($)	Dec. 29, 2019	Dec. 30, 2018	Jul. 02, 2023 USD ($)
Concentration of Credit Risk [Line Items]
Number of employees | Employee			131,900
Common Stock, Par or Stated Value Per Share | $ / shares			$ 1.00	$ 1.00
Proceeds from Kenvue initial public offering			$ 4,241	$ 0	$ 0
Realized gain (loss) on investment		$ 2,500
Number of business segments | Segment			2
Supplier finance program, obligation, current			$ 700	$ 700
Supplier Finance Program, Obligation, Current, Statement of Financial Position [Extensible Enumeration]			Accounts Payable, Current	Accounts Payable, Current
Minimum reverse repurchase agreement collateral (as a percent)			102.00%
Accrued rebates, returns and promotions			$ 16,001	$ 13,579
Sales return reserve (as a percent)			1.00%	1.00%	1.00%
Percentage of profit share payments (less than)			2.00%	3.00%	3.00%
Cost of products sold			$ 26,553	$ 24,596	$ 23,402
Shipping and handling costs as a percent of sales			1.00%	1.00%	1.00%
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]			Other assets, noncurrent	Other assets, noncurrent
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]			Accrued Liabilities, Current	Accrued Liabilities, Current
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]			Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Operating lease, right-of-use asset			$ 1,000
Operating lease liabilities			1,100
Operating lease costs			200	$ 200	$ 200
Cash paid for operating leases			200	200	200
Advertising expense			$ 500	$ 700	$ 1,200
U.S. statutory rate			21.00%	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			$ 4,500
TJCA , provisional liability, non-current			2,500
Repatriation of foreign earnings amount			500
Selling, marketing and administrative expenses			$ 21,512	$ 20,246	$ 20,118
Kenvue Inc.
Concentration of Credit Risk [Line Items]
Split-off percentage	80.10%
Kenvue Inc.
Concentration of Credit Risk [Line Items]
Common Stock, Par or Stated Value Per Share | $ / shares		$ 0.01
Sale of stock (in USD per share) | $ / shares		$ 22.00
Johnson & Johnson | Kenvue Inc.
Concentration of Credit Risk [Line Items]
Percentage ownership after transaction		89.60%
Common stock, value								$ 1,300
Percentage ownership after transaction	9.50%
IPO | Kenvue Inc.
Concentration of Credit Risk [Line Items]
Sale of stock, number of shares issued in transaction (in shares) | shares		198,734,444
Proceeds from Kenvue initial public offering		$ 4,200
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 | Project Concentration Risk
Concentration of Credit Risk [Line Items]
Concentration risk, threshold percentage (as a percent)			0.05	0.05	0.05
Shipping and Handling
Concentration of Credit Risk [Line Items]
Cost of products sold				$ 800	$ 800
Selling, marketing and administrative expenses			$ 900
Pharmaceutical
Concentration of Credit Risk [Line Items]
Accrued rebates, returns and promotions			$ 11,500	$ 9,600