Supplemental Financial Statement Information (Property and Equipment) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment, Net [Abstract]
Property and equipment, gross	$ 109,684	$ 104,207
Less: accumulated depreciation	(32,937)	(30,561)
Property and equipment, net	76,747	73,646
Land and buildings
Property, Plant and Equipment, Net [Abstract]
Property and equipment, gross	41,372	39,865
Information technology assets
Property, Plant and Equipment, Net [Abstract]
Property and equipment, gross	38,534	36,840
Construction in progress
Property, Plant and Equipment, Net [Abstract]
Property and equipment, gross	22,834	21,036
Leasehold improvements
Property, Plant and Equipment, Net [Abstract]
Property and equipment, gross	6,761	6,310
Furniture and fixtures
Property, Plant and Equipment, Net [Abstract]
Property and equipment, gross	$ 183	$ 156