Property and Equipment - Components (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Gross property and equipment	$ 173,548	$ 119,680
Total accumulated depreciation and amortization	60,434	46,975
Total property and equipment, net	113,114	72,705	$ 61,797
Land and buildings
Property, Plant and Equipment [Line Items]
Gross property and equipment	57,324	39,223
Equipment
Property, Plant and Equipment [Line Items]
Gross property and equipment	97,224	71,310
Other assets
Property, Plant and Equipment [Line Items]
Gross property and equipment	3,772	3,111
Construction in progress
Property, Plant and Equipment [Line Items]
Gross property and equipment	$ 15,228	$ 6,036