Segments of Business and Geographic Areas - Schedule of Segment Reporting By Geographic Area (Details) $ in Millions	12 Months Ended
	Dec. 29, 2024 USD ($) segment	Dec. 31, 2023 USD ($)	Jan. 01, 2023 USD ($) Segment
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales to Customers	$ 88,821	$ 85,159	$ 79,990
Assets	$ 180,104	167,558
Number of segments	2		3
Equity securities, FV-NI, gain (loss)	$ (400)	(400)
Restructuring	234	489	$ 275
Gain (loss) related to litigation settlement		100
Research and development in process	$ 211	313	783
Impairment, Intangible Asset, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other (income) expense, net
Property, Plant and Equipment
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	$ 20,518	19,898
Other Intangible Assets
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	81,818	70,733
bermekimab | In Process Research and Development
Revenues from External Customers and Long-Lived Assets [Line Items]
Impairment of intangible assets, excluding goodwill			$ 800
Baby Powder | Talc
Revenues from External Customers and Long-Lived Assets [Line Items]
Loss contingency, loss in period	$ 5,100	$ 7,000
Wholesaler 1 | Sales Revenue, Net | Wholesaler Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)	20.50%	18.20%	18.90%
Wholesaler 2 | Sales Revenue, Net | Wholesaler Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)	15.60%	15.10%	15.00%
Wholesaler 3 | Sales Revenue, Net | Wholesaler Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)	12.30%	14.20%	13.80%
Innovative Medicine
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales to Customers	$ 56,964	$ 54,759	$ 52,563
Restructuring	102		100
Realized gain (loss)	100	(400)	(700)
Gain (loss) related to litigation settlement		100
Gain (loss) on divestiture		(200)
Litigation expense			100
Innovative Medicine | Momenta
Revenues from External Customers and Long-Lived Assets [Line Items]
Impairment of intangible assets, excluding goodwill	200	200
MedTech
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales to Customers	31,857	30,400	27,427
Restructuring			300
Gain (loss) on divestiture	200
Acquisition costs, period cost	300	200	300
Regulation charge	200	300	300
Litigation expense	300		600
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales to Customers	50,302	46,444	41,981
United States | Innovative Medicine
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales to Customers	33,970	31,169	28,604
United States | MedTech
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales to Customers	16,332	15,275	13,377
Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales to Customers	88,821	85,159	79,990
Long-Lived Assets	101,119	89,439
Restructuring	269	798
Operating Segments | Innovative Medicine
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales to Customers	56,964	54,759	52,563
Assets	57,070	58,324
Supplies expense	100	700	1,500
Restructuring	102	479
Operating Segments | MedTech
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales to Customers	31,857	30,400	27,427
Assets	84,322	74,710
Restructuring	167	319
Operating Segments | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales to Customers	50,302	46,444	41,981
Long-Lived Assets	70,670	54,832
Operating Segments | Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales to Customers	20,212	20,410	20,664
Long-Lived Assets	27,267	31,616
Operating Segments | Western Hemisphere excluding U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales to Customers	4,714	4,549	4,108
Long-Lived Assets	1,728	1,491
Operating Segments | Asia-Pacific, Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales to Customers	13,593	13,756	$ 13,237
Long-Lived Assets	1,454	1,500
Segment Reporting, Reconciling Item, Corporate Nonsegment
Revenues from External Customers and Long-Lived Assets [Line Items]
Other non long-lived assets	77,768	76,927
Segment Reporting, Reconciling Item, Corporate Nonsegment | General Corporate
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	1,217	1,192
Assets	$ 38,712	$ 34,524