Fixed Assets - Summary of Fixed Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Fixed assets gross	$ 29,744	$ 35,009
Less: Accumulated depreciation	22,918	25,739
Fixed assets less accumulated depreciation	6,826	9,270
Land
Property Plant And Equipment [Line Items]
Fixed assets gross	362	483
Buildings & improvements
Property Plant And Equipment [Line Items]
Fixed assets gross	3,757	5,156
Machinery & equipment
Property Plant And Equipment [Line Items]
Fixed assets gross	$ 25,625	$ 29,370

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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