PROPERTY AND EQUIPMENT, NET - Narrative (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Property, Plant and Equipment [Abstract] | |||
| Depreciation expense | $ 505 | $ 444 | $ 410 |
| Amortization expense for capitalized internally developed and purchased software | $ 343 | $ 298 | $ 287 |