Supplemental Balance Sheet Information - PP&E (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Property, plant and equipment - at cost
Property and equipment, at cost	$ 26,650	$ 26,124
Less: Accumulated depreciation	(17,229)	(16,791)
Property, Plant and Equipment - net	9,421	9,333
Land
Property, plant and equipment - at cost
Property and equipment, at cost	338	351
Buildings and leasehold improvements
Property, plant and equipment - at cost
Property and equipment, at cost	8,021	7,877
Machinery and equipment
Property, plant and equipment - at cost
Property and equipment, at cost	16,866	16,586
Construction in progress
Property, plant and equipment - at cost
Property and equipment, at cost	$ 1,425	$ 1,310