GOODWILL AND INTANGIBLE ASSETS - Intangible Assets (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets, Net [Abstract]
Gross	$ 34	$ 2
Accumulated Amortization	1	0
Net	$ 33	2
Acquired technology
Finite-Lived Intangible Assets [Line Items]
Amortizable Lives	7 years
Finite-Lived Intangible Assets, Net [Abstract]
Gross	$ 20	0
Accumulated Amortization	0	0
Net	20	0
Acquired relationships
Finite-Lived Intangible Assets, Net [Abstract]
Gross	11	2
Accumulated Amortization	1	0
Net	10	2
Other
Finite-Lived Intangible Assets, Net [Abstract]
Gross	3	0
Accumulated Amortization	0	0
Net	$ 3	$ 0
Minimum | Acquired relationships
Finite-Lived Intangible Assets [Line Items]
Amortizable Lives	5 years
Minimum | Other
Finite-Lived Intangible Assets [Line Items]
Amortizable Lives	2 years
Maximum | Acquired relationships
Finite-Lived Intangible Assets [Line Items]
Amortizable Lives	15 years
Maximum | Other
Finite-Lived Intangible Assets [Line Items]
Amortizable Lives	3 years