ACCUMULATED OTHER COMPREHENSIVE LOSS - Schedule of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	$ 1,136	$ 2,815	$ 5,944	$ 3,258
Foreign currency translation adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(2,046)	(2,111)
Pension adjustment, net of tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(40)	(26)
Ending Balance
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	$ (2,086)	$ (2,137)	$ (1,896)	$ (2,108)