Supplemental Financial Statement Information (Property and Equipment) (Details) - USD ($) $ in Millions |
Jun. 30, 2021 |
Dec. 31, 2020 |
|---|---|---|
| Property, Plant and Equipment, Net [Abstract] | ||
| Property and equipment, gross | $ 137,075 | $ 126,462 |
| Less: accumulated depreciation | (45,378) | (41,713) |
| Property and equipment, net | 91,697 | 84,749 |
| Land and buildings | ||
| Property, Plant and Equipment, Net [Abstract] | ||
| Property and equipment, gross | 55,910 | 49,732 |
| Information technology assets | ||
| Property, Plant and Equipment, Net [Abstract] | ||
| Property and equipment, gross | 51,188 | 45,906 |
| Construction in progress | ||
| Property, Plant and Equipment, Net [Abstract] | ||
| Property and equipment, gross | 21,825 | 23,111 |
| Leasehold improvements | ||
| Property, Plant and Equipment, Net [Abstract] | ||
| Property and equipment, gross | 7,951 | 7,516 |
| Furniture and fixtures | ||
| Property, Plant and Equipment, Net [Abstract] | ||
| Property and equipment, gross | $ 201 | $ 197 |