INCOME TAXES - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2020	Dec. 31, 2019
Income Tax Contingency [Line Items]
Effective income tax rate, percent	19.80%	404.40%	28.70%	43.20%
Unrecognized tax benefits that would impact effective tax rate	$ 7		$ 7			$ 21
Penalties and interest accrued	18		$ 18			$ 41
Effective income tax rate reconciliation, CARES act, percent			4.40%
Forecast
Income Tax Contingency [Line Items]
Effective income tax rate reconciliation, CARES act, percent					3.90%
Indemnified tax liability
Income Tax Contingency [Line Items]
Penalties and interest accrued	$ 4		$ 4