Property, Plant, and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 20,770	$ 19,730
Accumulated depreciation	12,249	11,198
Net property, plant and equipment	8,521	8,532
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 3,460	$ 3,399
Building and Building Improvements [Member] | 1 - 10 years
Property Plant Equipment Useful Lives Total Depreciated Percentages [Abstract]
Ratio of depreciation by useful asset life over total depreciation of asset (in hundredths)	11.00%	11.00%
Building and Building Improvements [Member] | 11 - 20 years
Property Plant Equipment Useful Lives Total Depreciated Percentages [Abstract]
Ratio of depreciation by useful asset life over total depreciation of asset (in hundredths)	42.00%	42.00%
Building and Building Improvements [Member] | 21 - 30 years
Property Plant Equipment Useful Lives Total Depreciated Percentages [Abstract]
Ratio of depreciation by useful asset life over total depreciation of asset (in hundredths)	22.00%	22.00%
Building and Building Improvements [Member] | 31 - 40 years
Property Plant Equipment Useful Lives Total Depreciated Percentages [Abstract]
Ratio of depreciation by useful asset life over total depreciation of asset (in hundredths)	25.00%	25.00%
Land
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 248	$ 228
Machinery, equipment and other
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 17,062	$ 16,103
Machinery, equipment and other | 1 - 5 years
Property Plant Equipment Useful Lives Total Depreciated Percentages [Abstract]
Ratio of depreciation by useful asset life over total depreciation of asset (in hundredths)	35.00%	34.00%
Machinery, equipment and other | 6 - 10 years
Property Plant Equipment Useful Lives Total Depreciated Percentages [Abstract]
Ratio of depreciation by useful asset life over total depreciation of asset (in hundredths)	56.00%	57.00%
Machinery, equipment and other | 11 - 20 years
Property Plant Equipment Useful Lives Total Depreciated Percentages [Abstract]
Ratio of depreciation by useful asset life over total depreciation of asset (in hundredths)	9.00%	9.00%
Minimum | Building and Building Improvements [Member] | 1 - 10 years
Property, Plant and Equipment [Line Items]
Property, plant, and equipment useful lives	1 year
Minimum | Building and Building Improvements [Member] | 11 - 20 years
Property, Plant and Equipment [Line Items]
Property, plant, and equipment useful lives	11 years
Minimum | Building and Building Improvements [Member] | 21 - 30 years
Property, Plant and Equipment [Line Items]
Property, plant, and equipment useful lives	21 years
Minimum | Building and Building Improvements [Member] | 31 - 40 years
Property, Plant and Equipment [Line Items]
Property, plant, and equipment useful lives	31 years
Minimum | Machinery, equipment and other | 1 - 5 years
Property, Plant and Equipment [Line Items]
Property, plant, and equipment useful lives	1 year
Minimum | Machinery, equipment and other | 6 - 10 years
Property, Plant and Equipment [Line Items]
Property, plant, and equipment useful lives	6 years
Minimum | Machinery, equipment and other | 11 - 20 years
Property, Plant and Equipment [Line Items]
Property, plant, and equipment useful lives	11 years
Maximum | Building and Building Improvements [Member] | 1 - 10 years
Property, Plant and Equipment [Line Items]
Property, plant, and equipment useful lives	10 years
Maximum | Building and Building Improvements [Member] | 11 - 20 years
Property, Plant and Equipment [Line Items]
Property, plant, and equipment useful lives	20 years
Maximum | Building and Building Improvements [Member] | 21 - 30 years
Property, Plant and Equipment [Line Items]
Property, plant, and equipment useful lives	30 years
Maximum | Building and Building Improvements [Member] | 31 - 40 years
Property, Plant and Equipment [Line Items]
Property, plant, and equipment useful lives	40 years
Maximum | Machinery, equipment and other | 1 - 5 years
Property, Plant and Equipment [Line Items]
Property, plant, and equipment useful lives	5 years
Maximum | Machinery, equipment and other | 6 - 10 years
Property, Plant and Equipment [Line Items]
Property, plant, and equipment useful lives	10 years
Maximum | Machinery, equipment and other | 11 - 20 years
Property, Plant and Equipment [Line Items]
Property, plant, and equipment useful lives	20 years