LEASES - Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Operating lease ROU assets, included in Other assets	$ 45	$ 46
Current operating lease liabilities, included in Accrued expenses and other current liabilities	6	6
Noncurrent operating lease liabilities, included in Other liabilities	44	46
Total operating lease liabilities	50	52
Property and equipment, at cost	170	168
Accumulated amortization	(31)	(25)
Property and equipment, net	139	143
Total finance lease liabilities	86	90
Project Debt, Current
Lessee, Lease, Description [Line Items]
Current obligations of finance leases, included in Current portion of long-term debt	6	6
Project Debt, Noncurrent
Lessee, Lease, Description [Line Items]
Finance leases, net of current obligations, included in Long-term debt	73	78
Long Term Debt, Excluding Current Maturities
Lessee, Lease, Description [Line Items]
Finance leases, net of current obligations, included in Long-term debt	6	6
Long Term Debt, Current Maturities
Lessee, Lease, Description [Line Items]
Current obligations of finance leases, included in Current portion of long-term debt	$ 1	$ 0