Property, Plant, and Equipment - Long-lived Assets by Geographic Areas (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	$ 13,900	$ 12,969
US [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	7,821	7,194
Developed Europe [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	4,775	4,238
Developed Rest Of World [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	413	453
Emerging Markets [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	$ 890	$ 1,083