LEASES - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Leases [Abstract]
Property and equipment, at cost	$ 170		$ 170
Finance Lease, Right-Of-Use Asset, Accumulated Depreciation	35		$ 33
Operating cash flows related to operating leases	3	$ 2
Financing cash flows related to finance leases	$ 2	$ 2
Weighted average remaining lease term (in years): operating	11 years 2 months 12 days		11 years 7 months 6 days
Weighted average remaining lease term (in years): finance	30 years 9 months 18 days		31 years 9 months 18 days
Weighted average discount rate: operating	4.54%		4.63%
Weighted average discount rate: finance	5.06%		5.06%
Operating Lease, Liability, Noncurrent	$ 42		$ 43
Operating Lease, Liability	$ 49		$ 49