Property and Equipment - Components (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Gross property and equipment	$ 119,680	$ 95,770
Total accumulated depreciation	46,975	33,973
Total property and equipment, net	72,705	61,797	$ 48,866
Land and buildings
Property, Plant and Equipment [Line Items]
Gross property and equipment	39,223	31,741
Equipment
Property, Plant and Equipment [Line Items]
Gross property and equipment	71,310	54,591
Other assets
Property, Plant and Equipment [Line Items]
Gross property and equipment	3,111	2,577
Construction in progress
Property, Plant and Equipment [Line Items]
Gross property and equipment	$ 6,036	$ 6,861