Summary of Significant Accounting Policies (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment
Property, plant and equipment, at cost	$ 9,291	$ 8,419
Accumulated depreciation	(5,066)	(4,831)
Property, plant, and equipment, net	4,225	3,588
Land and land improvements
Property, Plant and Equipment
Property, plant and equipment, at cost	420	415
Buildings and improvements
Property, Plant and Equipment
Property, plant and equipment, at cost	1,834	1,798
Machinery and other equipment
Property, Plant and Equipment
Property, plant and equipment, at cost	5,105	4,711
Capitalized software costs
Property, Plant and Equipment
Property, plant and equipment, at cost	537	439
Leasehold improvements
Property, Plant and Equipment
Property, plant and equipment, at cost	$ 1,395	$ 1,056
Minimum | Capitalized software costs
Property, Plant and Equipment
Property, plant and equipment, estimated useful life	3 years
Maximum | Land and land improvements
Property, Plant and Equipment
Property, plant and equipment, estimated useful life	40 years
Maximum | Buildings and improvements
Property, Plant and Equipment
Property, plant and equipment, estimated useful life	45 years
Maximum | Machinery and other equipment
Property, Plant and Equipment
Property, plant and equipment, estimated useful life	20 years
Maximum | Capitalized software costs
Property, Plant and Equipment
Property, plant and equipment, estimated useful life	5 years