SEGMENT INFORMATION - Schedule of Segment Reporting Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Interest income	$ 17	$ 15	$ 53	$ 49
Total revenues	1,232	1,252	3,762	3,776
Depreciation and amortization of intangible assets	16	19	50	56
Stock based compensation	17	15	48	53
Interest expense, bank fees and other	13	15	42	47
Income Taxes	16	13	60	67
Net income	34	45	156	196
Reportable Segment
Segment Reporting Information [Line Items]
Interest income			53	49
Total revenues			3,762	3,776
Workers' compensation costs			57	39
Health insurance costs			2,775	2,733
Sales & marketing			178	192
Client support costs			127	139
Corporate administration			115	114
System support & development			149	140
Depreciation and amortization of intangible assets			50	56
Stock based compensation			48	53
Other			5	0
Interest expense, bank fees and other			42	47
Income Taxes			60	67
Net income			156	196
Professional service revenues
Segment Reporting Information [Line Items]
Service revenues	169	184	550	584
Professional service revenues | Reportable Segment
Segment Reporting Information [Line Items]
Service revenues			550	584
Insurance service revenues
Segment Reporting Information [Line Items]
Service revenues	$ 1,046	$ 1,053	3,159	3,143
Insurance service revenues | Reportable Segment
Segment Reporting Information [Line Items]
Service revenues			$ 3,159	$ 3,143