SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Prepaid Expenses and Other (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Prepaid insurance	$ 6	$ 4
Prepaid fees and licenses	4	3
Income tax receivable	19	38
Other	14	5
Total prepaid expenses and other	$ 43	$ 50