Fixed Assets (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Land	$ 425	$ 412
Buildings and improvements	6,486	5,727
Machinery, tools and equipment	15,119	13,476
Other, including assets under construction	2,054	1,749
Fixed assets	24,084	21,364
Accumulated depreciation	11,787	11,178
Fixed assets, net	12,297	10,186
Property Plant And Equipment [Line Items]
Depreciation	$ 1,240	$ 1,178	$ 1,105
Land Buildings And Improvements [Member] \| Maximum [Member]
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Land Buildings And Improvements [Member] \| Minimum [Member]
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life	12 years
Machinery And Equipment [Member] \| Maximum [Member]
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life	20 years
Machinery And Equipment [Member] \| Minimum [Member]
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years

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 of building structures held for productive use including addition, improvement, or renovation to the structure, including, but not limited to, interior masonry, interior flooring, electrical, and plumbing.

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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Amount before accumulated depletion of real estate held for productive use, excluding land held for sale.

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Amount before accumulated depreciation of tangible personal property used to produce goods and services, including, but is not limited to, tools, dies and molds, computer and office equipment.

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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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services 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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Amount before accumulated depreciation, depletion and amortization of other physical assets used in the normal conduct of business to produce goods and services and not intended for resale.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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