Property, plant and equipment - Property, Plant and Equipment at Cost and Accumulated Depreciation (Details) - USD ($) $ in Millions	Dec. 31, 2023	Jan. 01, 2023
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 47,776	$ 43,534
Less accumulated depreciation	27,878	25,552
Total property, plant and equipment, net	19,898	17,982
Land and leasehold improvements
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	795	784
Building and building equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	12,375	11,470
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	28,979	26,603
Construction in progress
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 5,627	$ 4,677