STOCK BASED COMPENSATION - Schedule of Stock-Based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock based compensation expense	$ 15	$ 16	$ 43	$ 46
Total stock based compensation capitalized	1	0	2	1
Cost of providing services
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock based compensation expense	3	3	10	10
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock based compensation expense	2	2	6	5
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock based compensation expense	9	9	24	28
Systems development and programming costs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock based compensation expense	$ 1	$ 2	$ 3	$ 3